A large number of classification systems exist to assist in the evaluation and treatment of periprosthetic fractures following joint replacement. They vary in the language or categorisation they employ, the joints to which they are differently applied, the factors they assess, and the hierarchy or importance assigned to those factors. Not all incorporate the three most important variables which should govern treatment (fracture location, implant fixation, bone quality), nor the factors which have been demonstrated to most prominently influence outcomes. To a greater or lesser extent they attempt to include the principles of the Vancouver Classification System, and yet they differ in ways that lead to awkwardness in their application within the clinical setting. As an example, for fractures of the patella alone, three different systems have been proposed.

As the result of an international effort endorsed by the AO/OTA, the Universal Classification System, or UCS, has been developed. It incorporates the most important factors that should influence evaluation, treatment, and outcomes evaluation. It applies the system to the musculoskeletal system as a whole, regardless of the joint involved or the bone that is broken. And it uses a single common language to describe the injury and prescribe the logical principles of treatment.

It is hoped the UCS will appeal to our colleagues worldwide and will assist all of us in the care of our patients who suffer a periprosthetic fracture after joint replacement; be that the hip, knee, ankle, shoulder, elbow or wrist. The UCS can be applied with equal ease and merit to all.

While short stem designs are not a new concept, interest has surged with increasing popularity of less invasive techniques. If the goal of the tapered stem is to load preferentially proximally, why do we need a stem at all? Perhaps the only reason to use a tapered, long stem is to prevent varus; however, studies have shown that varus malalignment of a tapered stem does not affect results. Short stems are easier to insert, especially when using an anterior approach such as the anterior supine intermuscular in which the proximal femur is elevated anteriorly from the wound during stem insertion. Femoral preparation can be accomplished with straightforward broaching of the canal, without use of reamers. Short stems are bone conserving. They violate less femoral bone stock, providing more favorable conditions should a revision be required. However, ease of insertion and bone conservation matter little if not supported by clinical results. Thus, we reviewed our early experience with 2094 patients undergoing 2457 primary THA using short, tapered titanium, porous plasma spray-coated femoral components since January 2006 at our center. The TaperLoc Microplasty stem (Biomet, Warsaw, IN) has been used in 1881 THA, and the TaperLoc Complete Microplasty stem (Biomet) in 576. Patient age averaged 63.6 years. Increased offset was used in 1990 hips (81%). The surgical approach was less invasive direct lateral (LIDL) in 1194 THA (49%), anterior supine intermuscular (ASI) in 1117 (46%), and standard direct lateral (Std) in 146 (6%). Follow-up averaged 20 months. Thirty-five stems (1.4%) have been revised: 15 for infection (12 LIDL, 3 ASI), 1 same day revision for intraoperative femoral shaft perforation (Std), 1 at 3 days for patellar dislocation (LIDL), 2 for early subsidence (1 LIDL, 1 ASI), 13 for periprosthetic femoral fracture (1 Std, 12 ASI), 2 for aseptic loosening (1 LIDL, 1 ASI), and 1 stem well fixed (ASI) removed for loose cup and unable to disarticulate trunnion.

What lessons have we learned? First, we usually require one or two diameter sizes larger with short porous tapered stem versus the standard length version of the same design. The surgeon should be aggressive with sizing, pushing to the largest size possible. Use the broach like a rasp. Drive the component in valgus during insertion. Upon seating the component, do a trial reduction using the shortest available neck length. The component will generally sit slightly prouder than the broach and may require additional effort to seat completely.

Conservation of existing bone stock, compatibility with soft-tissue sparing surgery, more physiologic loading of the proximal femur, and versatility with varying femoral anatomy make the short taper an attractive implant option. The tapered wedge short stem represents the natural evolution of joint arthroplasty to a smaller, less-invasive, and more efficient implant.

Fixation of the femoral component in total hip arthroplasty is a surgical challenge in the best of circumstances. Achieving immediate fixation without breaking the femur is a challenge, even to highly skilled and experienced arthroplasty surgeons. Surgical procedures are available that offer cosmetic benefit or a slightly quicker recovery, but accepting this compromise for fixation should be avoided.

The mechanical environment of the femoral component is challenging. The implant is exposed to offset loading in two planes, which results in substantial bending stress and rotational loads in the frontal plane as well as bending stress and torsional loads in the sagittal plane. The proximal femur is built to transmit load through the surface fibers, not the central cavity, so efforts to change it to a centrally loaded structure are fraught with difficulty. The entire structure should be used. The least reliable material is the cancellous bone in the intertrochanteric metaphysis and the most effective is the cancellous bone of the femoral neck and cortical bone of the upper diaphysis. For best fixation of the femoral component, the cortical bone of the upper metaphysis should be contacted, and the diaphyseal cortical bone actually should be grooved by the femoral stem during insertion.

Approach to the hip is important in fixation of the femoral component. Approaches that require femoral neck resection and use of a short stem are especially treacherous. The posterior approach is attractive because it encourages preservation of the femoral neck, and it provides straight access to the medullary canal of the femur while protecting the abductor muscles.

Static axial load in the extended position is most readily resisted by the femoral component. Distal cortical contact is very important to prevent toggle. Torsional loads generated from offset loading of the femoral head in flexion and with front-to-back acceleration generated loads during rapid gait are the most challenging in securing fixation of the implant. Ideal conditions include preservation of the femoral neck, engagement of a rectangular stem in a rectangular cavity, and mechanical lock into grooves in the diaphyseal cortical bone. If all these conditions are met, femoral component fixation can be achieved every time without damaging the abductor muscle group, and with minimal danger of femoral fracture.

A posterior approach with femoral neck preservation and a rectangular shaped femoral component with diaphyseal engaging stem is safe surgery and good mechanics. The anterior approach with femoral neck sacrifice and round, short stems is unsafe surgery and bad mechanics.

Having previously been a proponent of the advantages of the modular neck in total hip arthroplasty, I now take the opposite argument because of corrosion that happens with all taper junctions. The advantage of the modular neck is the “uncoupling” of femoral stem position from the final position of the femoral head. Surgical priorities frequently compete, whether positioning the stem for the best press-fit (for cementless fixation) or the best cement mantle (for cemented fixation), and positioning of the stem for preventing dislocation and improving function. My personal use of the modular neck spanned approximately 4 years from 2003–2008 and encompassed a total of 390 primary and revision cases. Excellent functional results were obtained, but some problems occurred that were associated with the modular neck and with large diameter head metal-metal articulations.

The modular neck was designed and studied at the Rizzoli Institute in Bologna, Italy with the conclusion that the strength of construct (titanium alloy neck in the titanium alloy stem) was sufficient and the potential for fretting at the modular junction was small and acceptable. Pre-market testing of the device met and exceeded all FDA suggested benchmarks.

The first modular neck fracture in my personal series occurred more than 3 years after implantation, in a large man with a long, varus modular neck. Within a year another fracture of a long, varus modular neck occurred in a heavy man. I now know of 6 modular neck fractures among the 390 cases. We have found evidence of corrosion, some very severe, in modular necks that we have revised (both fractured and intact modular necks). This corrosion is caused by Mechanically Assisted Crevice Corrosion associated with fretting at the modular junction which leads to removal of the titanium oxide “passivation” layer that generally forms on a titanium implant. This exposes more of the substrate metal to oxidation and can create pits that, in the notch-sensitive titanium alloy, can lead to the initiation of fracture. The hydrogen that is created from the corrosion reaction and diffused into the metal can cause “embrittlement” which predisposes it to fracture. We also have seen “hydrogen pneumarthrosis” associated with corrosion of the titanium modular neck in which the corrosion concentrated the hydrogen gas in the femoral stem below the modular neck and suddenly was released into the joint with significant pain. The hydrogen gas is irritating to the joint capsule and the patient presents with intense pain and gas in the joint, a clinical picture that can be confused with infection in the joint with a gas-forming organism. We now know that the condition is self-limiting, but suggests that revision of the modular neck construct would be a reasonable course of action.

Recently cobalt chromium modular necks have replaced those made of titanium alloy. Since cobalt-chromium is harder and stiffer, the milieu of the taper junction will be different than that of the titanium-titanium junction, and it has been suggested that this will allow safe and long-term use of the modular neck. The first titanium alloy necks were introduced in the early 1990s and it took until the mid-2000s to recognise problems. Last year the Stryker modular neck used with the Rejuvenate stem was recalled because of significant reaction associated with corrosion at the neck-to-stem junction.

Corrosion is inevitable at modular junctions exposed to cyclic loading, especially in the milieu of body fluids. We now know that ALTR occurs in response to taper junction corrosion as well, and the more modular junctions there are in a total hip construct, the more debris and potential reaction likely. Fixed neck stems provide satisfactory long-term fixation and function for patients, so despite a functional advantage to the modular neck, it is “a bridge too far”.

The advantages of modularity in both primary and revision hip surgery are well documented, and have been at the heart of innovation in hip implant design over the last two decades. Modularity allows us to address version, length and offset issues and to restore optimal hip biomechanics. There are, however, increasing clinical concerns associated with the failure of taper junctions. The use of large femoral heads and modular stems are now considered major risk factors for taper corrosion. I will summarise our laboratory and retrieval data on taper design and tribology in order to put in perspective the clinical use of modularity in hip arthroplasty.

Modular junctions rely on a frictional interlock. The engagement obtained and resulting micromotion is strongly influenced by taper size, taper length/engagement, material, surface finish, neck length and offset. In our quest for thinner femoral necks, greater offsets and bigger femoral heads, we have inadvertently created an environment that can generate fretting corrosion at modular junctions and leads to premature implant failure.

An inverted hip replacement setup was used similar to the specified ASTM test (ASTM F1875–98). Twenty-eight millimeter Cobalt Chrome (CoCr) femoral heads were coupled with either full length (standard) or reduced length (mini) 12/14 Titanium (Ti) stem tapers. These Ti stem tapers had either a rough or smooth surface finish whilst all the head tapers had a smooth finish. Wear and corrosion of taper surfaces were compared following a 10 million loading cycle. The surface roughness parameters on the head taper were significantly increased when the head-stem contact area was reduced. Similarly, the surface roughness parameters on the head taper were significantly increased when rough stem tapers were used. With rough male tapers the CoCr head taper became circumferentially ridged with distinct areas of pitting corrosion similar to that seen on some retrievals. In these tests similar surface morphology to that on retrieved femoral heads was seen on the female head taper.

Thirty-six millimeter CoCr femoral heads were also coupled with either a CoCr or Ti stem with 12/14 tapers all with smooth finish. Increasing perpendicular horizontal offsets in the sagittal plane created incremental increases in torque. A proportional relationship between torque and corrosion was observed for both CoCr-CoCr and CoCr-Ti material combinations.

In-vitro studies were used to evaluate the role of: taper size, angle mismatch, surface finish, and manufacturing tolerances on taper engagement. In-vitro loading analysis was performed to determine the bearing friction experienced by the taper connection. The component materials analysed were CoCr and Ti for stem design and CoCr/CoCr, ceramicized metal/CoCr, and CoCr/Ti for head/neck tapers. The high performance combinations included tapers with larger diameters, rougher surface finish, tighter tolerances and a proximal locking location. Loading studies demonstrate a 15 – 31% reduction in frictional torque (for 28, 36 and 40mm head sizes) using the ceramicized metal/XLPE couples compared to CoCr/XLPE couples.

Retrieval studies were conducted to assess taper corrosion using the Goldberg system and SEM analysis. Two hundred-nine taper surfaces, with in-vivo time varying from 1 week and 10 years, were analysed showing that ceramicized metal femoral heads have a lower corrosion score compared to CoCr femoral heads.

Understanding the key design and surgical factors that drive the performance of taper junctions is vital for the surgical community. There is a body of knowledge that supports appropriate taper use / modularity to help surgeons deal with complex situations. We must be careful not throw the baby out with the bathwater.

There has been a renewed interest in surface replacement arthroplasty over the last decade, with the hope and expectation that this procedure would provide an advantage over conventional total hip arthroplasty, especially in the young, active patient. More specifically, the promises of surface replacement arthroplasty have been: 1) preservation of bone stock so that future revisions would be easier, 2) potential to be minimally invasive in their approach, 3) better functional outcomes because of the stability associated with a larger femoral head with potential associated proprioceptive advantages, and 4) improved survivorship. Unfortunately, these promises have not been realised.

Surface replacement arthroplasty does maintain more initial bone stock on the femur, but also tends to remove more bone initially on the acetabular side. Long term, it is the loss of acetabular bone stock that is more problematic from a reconstructive perspective. Further, the “simple” revision afforded in surface replacement arthroplasty has led to reports of inferior clinical outcomes, especially with respect to subjective complaints of pain.

Surface replacement arthroplasty is more invasive than conventional total hip arthroplasty as the femoral head is maintained and the window to the acetabulum is subsequently partially blocked. This is exacerbated by the fact that many of these patients are young active males.

There is no compelling evidence that surface replacement arthroplasty offers improved functional outcomes over conventional total hip arthroplasty, particularly when considering gait and proprioception. Some studies have in fact shown inferior outcomes. The concept of the larger femoral head in surface replacement arthroplasty providing increased range of motion and subsequent better function is flawed as it is the head-to-neck ratio that appears to be a more important determinant of outcome in this sense. Total hip arthroplasty generally has a more favorable ratio.

Surface replacement arthroplasty has inferior survivorship to conventional total hip arthroplasty, even when accounting for the younger age of this patient cohort. This finding is consistent across multiple national joint replacement registries. The outcomes and survivorship are particularly poor in females, with many authors now advocating that the procedure be reserved for males.

Surface replacement arthroplasty has introduced several new problems and mechanisms of failures, most concerning of which is the formation of pseudotumors in some patients. It is unclear as to who is at risk for this significant complication, and the ability to diagnose and treat this disorder is difficult and still in evolution. Likely associated is the significant elevation of metal ions in the serum and urine of some surface replacement arthroplasty patients. Neck fractures and loss of bone stock around the femoral implant have also been noted as problematic for these devices. Some of these problems have led to specific surface replacement arthroplasty systems being recalled.

Finally, surface replacement arthroplasties are premium products with associated increased costs, which, frankly, are not justified.

Metal-on-metal hip arthroplasty has fallen out of favor because of complications arising from the articulation, namely metal sensitivity and accelerated wear. These complications can lead to early/mid-term failures from pain, osteolysis, implant loosening, and pseudotumor formation.

However, it has become clearer that MOM total hip arthroplasty behaves differently from MOM hip resurfacing, due to the additional junctions present in the total hip arthroplasty setting. Garbuz et al have demonstrated in a randomised controlled trial that MOM THA has significantly higher metal ion levels than MOM hip resurfacing. Clinical results of a MOM THA compared with a MOM HR using the same articulation also demonstrate significantly poorer results with the THA.

Newer literature has also shown that corrosion occurs at the taper junction of a THA due to the dissimilar metals. These corrosion products are likely what are causing a higher incidence of adverse local tissue reactions. Because a hip resurfacing implant is a monoblock ball, there is no taper junction of dissimilar metals that has the potential for corrosion.

National registry studies have also demonstrated a difference in the survival curves of MOM THA vs. hip resurfacing. MOM HR, in select patient groups, has a lower revision rate at 10 years than traditional metal-on-poly THA. Thus, to eliminate MOM hip resurfacing as a treatment option is akin to “throwing the baby out with the bathwater”, which the presenter deeply opposes.

Only a little over a decade ago the vast majority of primary total hip replacements performed in North America, and indeed globally, employed a conventional polyethylene insert, either in a modular version or in a cemented application. Beginning in the early 2000's there was an explosion in technology and options available for the bearing choice in total hip arthroplasty.

Highly cross-linked polyethylene was introduced in 1998, and within a few short years the vast majority of polyethylene inserts performed in North America were manufactured from this material. Globally there was a mixed picture with variable market penetration. Surgeons had seen historically poor results with attempts at “improving” polyethylene in the past and many were hesitant to use this new technology. Many randomised clinical trials have been performed and all have shown to a greater or lesser degree, that indeed the highly cross-linked polyethylene insert has undergone less linear and volumetric wear than its more conventional counterpart. This replicates well the hip simulator data. The challenge however is as we approached mid-term results, orthopaedic manufacturers began altering the polyethylene to improve wear and improve mechanical strength. Therefore while ten-year and greater data will ultimately be published, the actual polyethylene in use at that time will be a different material. Additionally while wear rates are undoubtedly lower, we are still waiting for long-term results of actual osteolytic lesion development and the effect that highly cross-linked polyethylene will have on this clinical scenario. That being said, with over a decade of clinical experience, unquestionably highly cross-linked polyethylene has truly been a revolution in design, essentially eliminating polyethylene wear as an early failure mode.

During this same decade metal-on-metal implants had seen a significant resurgence in use. Most major orthopaedic companies produced a metal-on-metal implant whether in the form of a more conventional modular insert, or a monoblock resurfacing-type implant, or both. Metal-on-metal implants had in-vitro advantages with very low wear rates. They allowed the use of large metal heads and articulations, thereby improving range of motion and stability. Concerns always existed regarding the production of metal ions and the potential for metal hypersensitivity, as well as possible systemic effects. Metal hypersensitivity remains a diagnosis of exclusion with no definitive diagnostic tests to either screen for it, or diagnose it, if suspected. Over the past few years metal-on-metal implant use has dropped significantly, to the point now in 2013, where the only remaining application is resurfacing implants in the younger male patient.

Ceramic-on-ceramic bearings enjoy the lowest wear rates of all currently available hip articulations. Historically there has been concern regarding fracturing of both the inserts and the heads, although current generation ceramic-on-ceramic bearings have a much lower reported fracture rate. The phenomenon of a squeaking articulation remains a concern for both patient and surgeon. Conflicting reports exist on whether this is related to implant mal-position or is a function of the bearing itself. As with other bearings, improvements in technology continue to evolve and newer ceramics have recently been introduced and are in clinical practice.

The future will continue to see the evolution of the articulation in total hip arthroplasty. Patients are undergoing total hip replacements at younger ages and clearly have higher demands than seen historically. That being said, two factors have will have a major influence on future developments. The tremendous clinical success of highly cross-linked polyethylene should have us all question the need for significant changes in bearing material and the current environment following the multiple issues with metal-on-metal is one of evolutionary, rather than revolutionary, design and introduction.

The initial success of modern total hip arthroplasty can in large part be attributed to the reliable fixation of the femoral component with the use of acrylic bone cement. Early success with cement led to a common pathway of development in North America and the European countries. Much of the early- to mid-term research concentrated on refinement of variables related to the methodology and technique of cement fixation. Scandinavian registries were subsequently able to report on improved survivorship with better cementing technique. The net effect has been standardisation towards a small number of cemented implants with good long-term outcomes representing the majority of stems implanted in Sweden, for example.

In North America, during the mid-term development of THA in the late 1980's, the term “cement disease” was coined and the cemented THA saw a precipitous decline in use, now to the point where many American orthopaedic residents are completing training never having seen a cemented THA. Modern uncemented femoral components can now claim good long-term survivorship, perhaps now comparable to cemented fixation. However, this has come at a cost with respect to the premium expense applied to the implant itself as well as lineage of failed uncemented constructs. The last several years have seen a proliferation of uncemented implants, usually at a premium cost, with no demonstrated improvement in survivorship. Osteolysis has not been solved with uncemented implants and cement disease has largely been recognised as a misnomer.

Long-term outcomes of cemented femoral fixation have consistently demonstrated excellent survivorship, even in the younger age group. Cemented stems allow for variable positioning of the stem to allow for better soft tissue balancing, without the need for proximal modularity. Cemented stems are more forgiving and fail less often secondary to a reduced incidence of intraoperative complications, such as periprosthetic fracture. Cemented stems tend to be less expensive and also have the advantage of adding antimicrobial agents into the cement. This is important in emerging markets. The next iteration of orthopaedic innovation driven by the emerging markets may indeed be back to the future.

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (Co-Cr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10 year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated Co-Cr stem. One study utilising pain drawings did establish that if a Co-Cr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross-section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications.

The first porous-coated femoral component approved for use without cement was released in 1983. Today, there are many implants with a similar amount of porous coating. The hallmark of these porous-coated implants is a cylindrical shape distally and a triangular metaphyseal shape. Extensively coated components gain initial stability in the femoral diaphysis.

Since 1982, we have used extensively porous-coated femoral components in all our patients. Our oldest series of patients is a consecutive non-selected group of 211 hips that have been followed for a mean of 20 years. Combining the loose and the revised, there is only a 3% femoral failure. In addition, we have studied patients with disease processes not originally thought to work well with cementless techniques, including rheumatoid arthritis, avascular necrosis and patients over 65.

Despite the good results, the main concern is that proximal bone loss secondary to the stress shielding caused by a stiff extensively porous-coated femoral component will lead to difficulty at the time of revision. At a mean 14 years, we have not seen any adverse clinical consequences that can be attributed to proximal stress shielding, though the longer term consequences of adaptive femoral remodeling need to be followed. In our patients, extensive proximal bone loss secondary to stress shielding is a radiographic sign of bone ingrowth that occurs in 25% of cases. In the remaining 70–75% of cases, lesser degrees of proximal bone loss occur which confirm bone ingrowth.

Extensively coated components gain stability in the femoral diaphysis. The femoral diaphysis is prepared with straight reamers until the reamer engages the cortex for 5cm. A slightly larger straight femoral component is inserted with a scratch fit. No matter what the shape of the femur or how osteoporotic the patient, there will always be 4–5cm of cortical bone for fixation of a straight 6 inch stem.

Dislocation remains among the most common complications of, and reasons for, revision of both primary and revision total hip arthroplasties in the United States. Hence, there is great interest in maximising stability to prevent this complication.

Highly cross-linked polyethylene has allowed us to increase femoral head size, without a clinically important increase in wear. Head size has long been recognised to have a strong influence on the risk of dislocation postoperatively. As femoral head size increases, stability is augmented, secondary to a decrease in component-to-component impingement, which is theoretically eliminated at head sizes greater than 36mm in diameter (however osseous impingement can still occur). Larger head sizes also greatly increase the “jump distance” required for the head to dislocate (in an appropriately positioned cup) and eliminate the need for skirts. Level one studies support the use of larger diameter heads as decreasing the risk of dislocation following primary and revision THA.

Larger diameter heads do, however, have negatives with the most recent concern being larger forces imparted upon the trunnion, which may contribute to adverse local tissue reactions (ALTR) which have recently been reported in patients with a metal on polyethylene bearing. However, in the series by Cooper et al, 32mm was the most common head size identified with no head sizes >36mm in this series. This suggests that the cause of ALTR is probably multifactorial and while femoral head size may be a contributor, the trunnion itself may be more important including its diameter, length and modulus of elasticity as well as the specific finish of the taper. Finally, when larger femoral head sizes are used in smaller acetabular components, the result is a thinner polyethylene liner, which may increase the risk of liner breakage. Larger diameter bearings may also increase the risk of squeaking in ceramic on ceramic bearing couples.

Hence, the decision on femoral head size probably should include a balance between patient risk factors for instability and the risks of increased head size. Hence for revision procedures, and in primary cases where the risk of dislocation is known to be high, the risk of a larger femoral head is probably outweighed by the benefits of enhanced stability if a larger femoral head is utilised.

Concerns with long-term fixation of cemented all-poly sockets have led to the near-universal acceptance of cementless fixation of the acetabulum.

The sockets most often utilised today are bone-ingrowth porous metal, made of titanium, cobalt-chrome, or hyper-porous materials such as tantalum trabecular metal.

Porous ingrowth sockets are extraordinarily reliable, with reports of 99–100% achieving stable fixation. The problem with sockets is not the fixation, but the bearing. Modular polyethylene liners are most commonly used, but wear on the primary bearing surface as well as backside wear can lead to osteolysis and late failure. Holes in the socket designed for supplemental screws act as a conduit for particles to enter the ace tabular bone where a cascade of inflammatory responses activate osteoclastic activity and bone destruction.

One alternative is a socket without holes, using spikes or fins for additional stability. The concern here is that the socket may not be completely seated and the surgeon is unaware.

Another alternative is the use of a monoblock acetabular component with the polyethylene molded to the metal shell. While excellent results are reported, the downside is an inability to exchange the polyethylene.

Resurfacing sockets are also monoblocks, and some offer peripheral supplemental screws. Here again, incomplete seating may occur, leaving a gap behind the dome. Serial x-rays almost always reveal that this gap gradually fills in.

Improvements in polyethylene, better locking mechanisms and alternative bearing materials such as ceramic and metal are the final steps to ensure acetabular durability.

This session will be practically oriented, focusing on important surgical decisions and on technical tips to avoid complications. The panel will be polled concerning individual preferences as regards the following issues in primary total hip arthroplasty: 1.) Perioperative antibiotics/blood management/preferred anesthetics, 2.) Surgical approach for primary total hip arthroplasty: indications or preferences for direct anterior, anterolateral, posterior, 3.) Acetabular fixation, 4.) Tips for optimising acetabular component orientation, 5.) Femoral fixation: (a) Indications for cemented and uncemented implants. (b) Role of hip resurfacing, 6.) Femoral head size, 7.) Bearing surface, 8.) Tips for optimising intraoperative hip stability, 9.) Tips for optimising leg length, 10.) Postoperative venous thromboembolism prophylaxis, 11.) Heterotopic bone prophylaxis, 12.) Postoperative pain management, 13.) Postoperative rehabilitation protocol: weight bearing, role of physical therapy, 14.) Postoperative activity restrictions, and 15.) Postoperative antibiotic prophylaxis for procedures.

To properly care for femoral neck fractures, the surgeon must decide which fractures are to be fixed and which fractures will require a prosthesis. In addition, the type of prosthesis, hemiarthroplasty versus total hip arthroplasty must be selected. Total hip arthroplasty is an option in the active elderly.

The literature supports internal fixation in non-displaced fractures. Current literature supports the fact that ORIF of displaced femoral neck fractures results in failure and re-operation of 20% to 30%. By considering arthroplasty when the patient has multiple co-morbidities including renal disease, diabetes, rheumatoid arthritis and severe osteoporosis the re-operation rate can be reduced significantly. The single most important factor in preventing failure with fixation is an anatomic reduction. A femoral neck fracture left in varus is doomed to failure and re-operation.

A prosthesis should be used in most displaced femoral neck fractures in patients physiologically older than 65. In active elderly patients total hip replacement should be considered. In elderly patients with multiple co-morbidities who are relatively inactive in a nursing home or lower level community ambulators, a hemi-prosthesis should be considered. The decision-making process is always shared with the patient.

When a prosthetic replacement is performed, the low level nursing home or community ambulator who is not expected to live longer than six to seven years is a candidate for a cemented hemi-arthroplasty. Studies report a 25% – 30% re-operation rate in hemi-arthroplasty if the patient survives greater than six to seven years. In the active elderly with little co-morbidity, a total hip replacement should be used. This is not only cost effective but provides the best pain relief of any of the options for treatment of displaced femoral neck fractures. Treatment of femoral neck fractures remains a challenge but the surgeon must select the proper treatment based on fracture displacement, physiologic age of the patient as well as co-morbidities of the patient.

Although the vast majority of fractures of the proximal femur will heal with well-done internal fixation, occasionally failure of fixation will occur. Having effective salvage options is important to restore function and minimise complications. In general, it is logical to separate salvage options into those for fractures of the femoral neck, and those for fractures of the intertrochanteric region. Additionally, patient age and remaining bone stock should be considered.

Femoral neck fracture fixation failure salvage, young patients: All efforts are focused on preserving the native femoral neck. Valgus producing osteotomy is typically indicated, and can be successful even with small patches of AVN.

Femoral neck fracture fixation failure salvage, older patients: Total hip arthroplasty is generally most predictable. Be prepared for very poor bone quality. Supplement uncemented acetabular component with multiple screws. Be prepared to cement femoral component, if necessary.

Intertrochanteric fracture fixation failure salvage, young patients: Repeat internal fixation attempts with fixed angle devices (such as a 95 degree blade plate) and bone grafting generally preferred. Avoid varus of proximal fragment and target inferior femoral head bone.

Intertrochanteric fracture fixation failure salvage, older patients: Total hip arthroplasty preferred. Long stems to bypass femoral shaft stress risers and “calcar replacement” stems may be necessary due to proximal bone defects. Trochanteric fixation must be stable. Results are generally good but trochanteric complaints are common.

THA after acetabular fracture presents unique technical challenges. These challenges include bone deformity, bone deficiency, sclerotic or dysvascular bone, non-united bony fragments, pelvic discontinuity, retained hardware, heterotopic ossification, previous incisions, and concerns regarding the sciatic nerve. Despite these challenges, with current treatment methods, a high degree of success can be achieved with modern technology.

Preoperative evaluation for infection - In previously operated acetabular fractures, infection is always a concern. Screening C-reactive protein and sedimentation rate may be performed. If a concern regarding infection is present, the hip may be aspirated; Incisions - In most cases, a previous incision may be utilised. If necessary, an incision may be extended or a new limb can be created and attention should be paid to maintaining optimal skin bridges.

In cases with a high degree of concern about infection, a staged procedure may be considered. However, in most cases, hardware removal can be done selectively at the time of THA surgery. Hardware that does not compromise placement of the THA may be left in place. Sometimes hardware can be cut off within the acetabulum to minimise exposure needs.

The reconstructive goal is to place the hip center as close as possible to normal hip center but also to gain good support of the socket on host bone. In most cases, both goals can be met. When necessary, some compromise in hip center of rotation may be considered to optimise implant stability on host bone. The principles of revision surgery are followed using uncemented acetabular components fixed with augmentation screws.

Most bone deficiencies may be managed with methods similar to revision hip surgery. However, in the acetabular fracture patient, usually the host femoral head is available and this can be used as bone graft, either in particulate or bulk form. Most cavitary deficiencies can be dealt with particulate bone graft. Some superolateral bone deficiencies from posterior wall fractures may be considered for bone grafting or augmentation techniques.

Nonunited fractures are not uncommon in these circumstances. Small wall nonunions may be managed as noted above for bone deficiency. If pelvic discontinuity is present, it is usually best treated by following the rules established for treatment of pelvic discontinuity with pelvic plating. Pelvic plating provides a reasonable likelihood of bone healing in these circumstances when combined with bone grafting techniques.

Heterotopic ossification is common in previously operated acetabular fractures. Removal of heterotopic bone at the time of surgery to gain hip motion is routine. Postoperative measures to reduce the likelihood of bone formation (that is either shielded radiation or use of a nonsteroid anti-inflammatory agent) may be strongly considered.

The sciatic nerve is at risk during these procedures. In many cases, avoiding the nerve and the region of the nerve is a reasonable approach. When a lot of work must be done on the posterior column, the surgeon needs to know exactly where the nerve is and in such cases the nerve may be exposed distally beneath the gluteus maximus tendon and followed proximally with careful and judicious dissection.

Results of total hip arthroplasty after acetabular fracture have varied in the past. More recent series have shown a high rate of acetabular fixation associated with uncemented hemispherical implants. Acetabular fracture patients are disproportionately young and active with unilateral hip disease and, therefore, bearing surfaces should be chosen accordingly.

The orthopaedic surgeon may need to act as an important adjunct to the oncologist in management of the cancer patient with metastatic hip disease. Management of the cancer patient with routine hip pathology may be relatively straightforward but the surgeon should note that the cancer patient may be on treatment protocols which affect wound healing, the immune system and the risk of DVT. The principles of managing metastatic disease include recognising the presence of lesions in bone about the hip, the occasional need for biopsy, the use of radiation in sensitive tumors and finally surgical stabilisation or replacement when needed. In some cases percutaneous cementation of metastatic disease or radiofrequency ablation may be appropriate. Factors which may complicate management of patients who have completed treatment of peri-pelvic cancer, may include radiation therapy which can lead to osteonecrosis of the acetabulum. Greater than 500 Cgy of radiation has been associated with high rates of acetabular fixation failure regardless of fixation type in several series. Decision making in these patients can be aided by consultation with previous radiation therapy providers to estimate the dose sustained by the local tissues under consideration. Increased rates of infection and wound healing have also been noted secondary to long term lymphatic obliteration caused by radiation. These concerns also affect the surgeon who must manage patients with acute metastatic disease who may also be undergoing chemotherapy as well as radiation.

Peri-operative fracture during routine THA represents one of the “not so fresh” feelings that occur for both patients and surgeons. With the increase in uncemented implants and MIS techniques this truly is a problem on the rise. We have recently examined and quantified the risk factors associated with proximal femoral fracture during THA. Risk factors (risk ratios) identified were: uncemented stems (8.9), anterolateral approach (7.4) and female gender (2.2). Fortunately, treatment with cerclage wiring for uncemented stems has facilitated excellent stem stability and acceptable survivorship with many different femoral component designs. Reduced proximal geometry stems that match the endosteal osseous anatomy have reduced fracture rates at our institution. In our series, cemented stems, however, had decreased survivorship in the presence of a proximal femoral fracture. MIS techniques may accelerate rehabilitation but they certainly permit limited visibility of the proximal femoral and acetabular anatomy and may result in less accurate component position. Relatively high fracture rates in series of MIS-THA have been reported. A bigger concern, however, is the unrecognised fracture that displaces postoperatively and requires a return to surgery for treatment with or without revision and mandates that we “see it before it sees us!” Cerclage wiring with looped Luque wires has been our treatment of choice for many years. Wires are significantly less expensive than cables and have proven to be durable in our series. They allow intraoperative repositioning and variable tightening in multiple locations. Cable fretting and breakage has been common in our experience with braided cable devices. Acetabular fracture during uncemented THA is most likely an under-reported occurrence and has been associated with elliptical component designs and under-reaming. In the presence of a stable cup, long-term performance has been acceptable.

Periprosthetic fractures in total hip arthroplasty lead to considerable morbidity in terms of loss of component fixation, loss of bone and subsequent functional deficits. We face an epidemic of periprosthetic fractures as the number of cementless implants inserted continues to rise and as the number of revisions continues to increase. The management of periprosthetic fractures requires careful preoperative imaging, planning and templating, the availability of the necessary expertise and equipment, and knowledge of the potential pitfalls so that these can be avoided both intra-operatively and in follow-up. There is a danger that these cases fall between the expertise of the trauma surgeon and that of the revision arthroplasty surgeon.

The past decade has afforded us clear treatment algorithms based on fracture location, component fixation and the available bone stock. We still nevertheless face the enduring challenge of an elderly population with a high level of comorbidity who struggle to rehabilitate after such injuries. Perioperative optimisation is critical as we have seen prolonged hospital stays, high rates of systemic complications and a significant short term mortality in this cohort.

We have also been presented with new difficult fracture patterns around anatomic cementless stems and in relation to tapered cemented and cementless stems. In many cases, fixation techniques are biomechanically and biologically doomed to fail and intramedullary stability, achieved through complex revision is required.

The treatment of unstable peri-prosthetic femur fractures can be technically challenging due to the weak non-supportive bone stock. We have seen an increase in the frequency of Type B3 fractures that require complex reconstruction with modular tapers, interlocking implants and proximal femoral replacements. Our reconstructive practice has evolved; the aims of femoral reconstruction include rotational and axial stability of the stem, near normal hip biomechanics and preserving as much femoral bone as possible. The advent of modular prostheses that gain distal fixation but have proximal options has extended the scope of this type of fixation. We now favor modular tapered stems that afford us the opportunity to reconstruct such femora whilst attempting to preserve the proximal bone. In effect, distal cone or taper fixation provides the initial stability required for the procedure to be successful but the proximal modular implant subsequently load shares to decrease stress shielding, distribute stress more evenly through the femur and minimise the risk of stem fracture. Such systems provide the intraoperative versatility that these cases require. The use of interlocking stems with coated ingrowth surfaces offers a relatively appealing solution for some complex fractures and avoids the complications that would be associated with unstable fixation or resection of the proximal femur.

Periprosthetic acetabular fractures are also increasingly recognised. This is in part due to the popularity of press fit components, which increase fracture risk both at the time of insertion and later due to medial wall stress shielding and pelvic osteolysis, and partly due to the increasing frequency of severe defects encountered at the time of revision surgery. These can present a very difficult reconstructive challenge and may require porous metal, cup-cage or custom reconstruction.

Periprosthetic fractures continue to cause problems worldwide. The sequelae of periprosthetic fractures include the financial cost of fixation or revision surgery, the associated morbidity and mortality in an elderly frail population, the difficulty with mobilisation if the patient cannot fully weight bear and a poor functional outcome in a proportion of cases. The battle over which patients or fractures require fixation and which require revision surgery continues.

Anterior supine intermuscular total hip arthroplasty (ASI-THA) has emerged as a muscle sparing, less-invasive procedure. The anterior interval is both intermuscular and internervous, providing the advantages of little or no muscle dissection, and a true minimally invasive alternative. It is versatile, with reported use expanding beyond the primary realm to revision and resurfacing THA as well as treatment of acute fracture in elderly patients, who due to their diminished regenerative capacity may benefit more from the muscle-sparing nature of the anterior approach. The ASI approach involves the use of a standard radiolucent operative table with the table extender at the foot of the bed and the patient supine. Fluoroscopy is used in every case. A table-mounted femur elevator is utilised to facilitate femoral preparation.

A retrospective review identified 824 patients undergoing 934 consecutive primary ASI-THA performed between January 2007 and December 2010. Age averaged 63.2 years (27–92), BMI averaged 29.9 kg/m2 (16.9–59.2). Gender was 49% males and 51% females. Stem types were short in 82% and standard length in 18%. Follow-up averaged 23.1 months (1–73). Operative time averaged 63.1 minutes (29–143). Blood loss averaged 145.3 minutes (25–1000). Transfusion rate was 3.3% (30 of 914) in single procedures and 80% (8 of 10) in simultaneous bilateral procedures. Length of stay averaged 1.7 days (1–12). Intraoperatively there were 3 calcar cracks and 1 canal perforation treated with cerclage cables. There were 6 wound complications requiring debridement. Four hips had significant lateral femoral cutaneous nerve parathesias not resolved at 12 months. One femoral nerve palsy occurred. At up to 73 months follow-up there have been 21 revisions (2.2%): 2 infection, 1 malpositioned cup corrected same day, 5 metal complications, 2 dislocations, 2 loose cups with one requiring concomitant stem revision secondary to inability to disarticulate trunnion, 1 femoral subsidence and 8 periprosthetic femoral fractures.

Primary THA can be safely performed utilising this muscle-sparing approach. We did not see an alarmingly high rate of complications. Instead, rapid recovery and quick return to function were observed. ASI-THA appears to be safe. The recovery advantage utilising this surgical approach is irrefutable. There are complications, most notably periprosthetic femur fracture. The rate, however, appears to be low and decreases with increased experience. There is no need for a special operative or fracture table to perform the procedure. Whether the complication rate is higher with the use of these expensive devices is unknown, but our results demonstrate a 2.2% reoperation rate with the use of the ASI approach performed on a standard OR table. Continued refinement of the technical aspects of ASI-THA may lessen the complication rate.

Total hip replacement can be performed through multiple surgical approaches including anterior, anterolateral, lateral, transtrochanteric, posterolateral, posterior and the two incision technique. The overwhelming majority of hip replacement surgery today is performed through a posterolateral approach and this approach certainly has many advantages. The posterolateral approach can be extended without difficulty, it is expeditious, has reduced blood loss, there is little muscle damage and recovery is rapid. The major disadvantage of the approach that has been cited is its increased dislocation rate which has become less of a problem with the advent of larger femoral heads and dual mobility acetabular components.

The less invasive posterolateral approach is performed through an incision of 8–10 centimeters and is suitable for patients with BMI index of less than 35. Deep dissection is less radical and the gluteus maximus tendon is not released and only the upper 1/4 of the quadratus femoris insertion is released. Full visualisation of the acetabulum must be accomplished with this approach and soft tissue releases of the labrum and anterior capsule must be performed to accomplish this. Similarly exposure of the entire proximal osteotomised femoral neck must be effected so that reaming and broaching can be performed safely. Special retractors have been developed to facilitate these techniques. Ongoing review of this procedure in almost 1500 patients operated on by me has yielded excellent radiographic and functional results. Complications have included a dislocation rate of 1.2%, femoral fracture 0.3% and sciatic neuropraxia of 0.3% all but one which resolved.

Rapid recovery from total hip replacement is multifactorial with current accelerated rehabilitation programs and improved pain management playing a role as well as surgical approach. The need for external support during ambulation with the mini-posterior approach rarely is greater than 3–4 weeks in the vast majority of patients. Hip precautions are used for a 4 week period. Hospital stay is 2–3 days and could be accelerated further in young, active patients.

There are many excellent approaches to the hip each of which has its advantages and disadvantages. The anterior approach is an excellent approach but requires advanced training, experience, a specialised table, longer surgical time, more difficultly with exposure with no evidence of advantage in outcome.

Ceramic-on-ceramic (COC) bearing surfaces have consistently demonstrated reliable clinical results with when coupled with appropriated designed femoral stems and acetabular shells. Ceramic bearing surfaces are highly wettable and display both boundary and hydrodynamic fluid-film lubrication modes, which lead to extremely low wear rates. Furthermore, COC bearing couples have been shown to exhibit virtually no risk of adverse biologic reaction and have not been associated with corrosion-induced adverse tissue reactions that occur with metal taper junctions, particularly head-neck taper junctions. The relative brittleness of ceramics initially was thought to be a major disadvantage; however, four decades of improvement in the manufacture of ceramics and rigorous proof testing has led an extremely low risk of fracture, perhaps lower than that for cross-linked polyethylene. More recently it has become increasing appreciated that nearly all revisions for squeaking have been restricted to specific designs and materials, including the use of a titanium elevated metal rim on the acetabular side, and more flexible femoral components made of a beta-titanium alloy (TMZF) which had thin necks and relative small tapers. Multiple clinical studies document excellent long-term survival of COC bearing couples in young patients with revision for any reason as the primary endpoint. Our own experience with 341 hips with 2 to 15 and average 9.1 year f/u demonstrates a 95% overall survivorship (revision for any reason) at 13 years in patients under 50 years of age at the time of surgery.

By contrast, cross-linked polyethylene bearings have not been studied so carefully and have not been shown to be superior to ceramic-ceramic bearings in young patients. These bearing surfaces represent a very heterogeneous group of products, with varying degrees of cross-linking, post-irradiation processing methods, and additives. Cross-linked polyethylenes in general have a lower fatigue strength than conventional polyethylene and are prone to fracture, especially when thin material is subjected to high stress. Some types of cross-linked polyethylenes are prone to in vivo oxidation, leading to further mechanical compromise over time. Studies also demonstrate the absence of reduction in femoral head penetration or risk of osteolysis in heads 32mm and larger, which are commonly used today. The most recent cross-linked polyethylene products have the least clinical support for their use. The long-term biologic effects of the smaller HXLPE wear particles and newer additives, including the more recently added vitamin E compounds are unknown. Indeed, in vitro, the debris has been shown to be cytotoxic. There is a paucity of survivorship data for hips utilising HXLPE, especially in younger, more active individuals. For these reasons, we believe that the ceramic-ceramic bearings are the gold standard for THA in the young patient and that cross-linked polyethylene bearing are being continually changed and have little long term clinical outcomes data to support their use.

Due to issues related to osteolysis which became increasingly evident in the 1990's, approaches to combat wear focused upon either improving ultra-high molecular grade polyethylene or to abandon it and employ alternative bearings: metal upon metal or ceramic upon ceramic (COC).

Ceramics have played a role in hip bearings for decades with much of the experience coming from Europe. While there is consistent evidence of low wear rates in this bearing couple due to its surface hardness, wettability and resultant low friction, problems unique to this bearing couple were noted: a small but real incidence of fracture, surface damage due to metal transfer and stripe wear as well as the unique issue of squeaking. What we have learned is that these hard bearings (either COC or Metal on Metal) despite being able to use larger diameter heads, are exquisitely sensitive to component position and orientation.

With the tremendous improvements in 2nd and now 3rd generation crosslinked polyethylenes demonstrating vastly reduced wear rates and having none of the issues of fracture, stripe wear, or squeaking, it remains unclear what role ceramic bearings have in modern use. Until the aforementioned issues are resolved, ceramic on ceramic bearings in the young patient should be used with caution. Ceramic-on-ceramic total hip arthroplasty: incidence of instability and noise.

Implant registries are set up to register implants. They therefore collect information about both primary and revision joint replacements. If a revision is linked to a primary it is then possible to determine the revision rate of the primary. This information is, however, of limited value as detailed information that affects the revision rate such as indications for the primary and the revision, and surgical technique used are not recorded. As a result comparisons of different implant designs and implant types are not reliable. For example implants that are commonly used in young or active patients are likely to have higher revision rates than those used in elderly sedate patients even though they may be better. Similarly, implants that are easy to revise will have higher revision rates than those more difficult to revise even if they provide better functional results. Finally, implants that are commonly used by more experienced surgeons will tend to have lower revision rates than those used by less experienced surgeons. Data from registries are therefore useful for identifying hypotheses that can formally be tested in other ways.

Over the past 40 years information from large institutional total joint registries have aided in patient clinical care and follow-up efforts, have helped drive improvements in clinical practice, and have been a powerful tool for generating research studies on large well documented populations of patients. Still, these efforts are limited in that they are expensive, usually reflect a single institutional experience, and results can be biased by the larger volumes or experience at the typically large academic centers which have such registries in place.

National registry efforts in other countries including Scandinavia, Australia, and the UK have resulted in improved outcomes and a decreased number of revision procedures by a combination of early identification and withdrawal of poorly performing implants, altered surgical techniques, implant choices and behaviors by surgeons, changes in practices by hospitals, and modification in requirements and incentives by payors and regulatory agencies.

The American Joint Replacement Registry (AJRR) is a collaborative multi-stakeholder, independent, not-for-profit 501 c3 organisation established in 2009 for data collection and quality improvement initiatives relating to total hip and knee arthroplasty. AJRR is a national registry effort with the goal of enrolling more than 90% of the over 5,000 hospitals performing nearly 1 million hip and knee arthroplasties each year in the US. AJRR is supported by contributions from the American Academy of Orthopedic Surgeons (AAOS), the American Association of Hip and Knee Surgeons (AAHKS), the Hip Society, the Knee Society, Health Insurers, Medical Device Manufacturers, and individual orthopaedic surgeons via designated contributions through the Orthopedic Research and Education Foundation (OREF).

The overarching goal of AJRR is to improve arthroplasty care for patients through the collection and sharing of data on all primary and revision total joint replacement procedures in the U.S. The mission of the registry is to enhance patient safety, and improve the value of arthroplasty care. This will be accomplished by providing national benchmarks for implant, surgeon and hospital performance which serves to modify behaviors thereby decreasing the revision burden, improving outcomes and reducing costs.

From the time of incorporation in 2009 up to October 2013 the AJRR has secured the participation of 218 hospitals in 47 different states in the formal enrollment process, and have level one data submission from more than 100 institutions on over 63,000 hip and knee procedures.

In addition to publicly available annual reports, confidential specific individual reports for hospitals, surgeons and manufacturers will be available by subscription with an option for future confidential online direct data queries by an individual or entity regarding their own individual performance compared to national benchmark values.

In summary, registry studies have provided a rich source of information for improving arthroplasty care over the past four decades, with the emergence and increasing interaction of national registries a major factor in current efforts to increase both the quality and value of the health care of entire populations. The development, support and continued expansion of a national registry in the US must remain a central focus if we wish to improve as much as possible the arthroplasty care provided to all patients in our country.

A national quality improvement initiative identified potentially avoidable complications, including venous thromboembolism (VTE) as “never events.” While the intent of this designation was to improve system-wide performance and to decrease medical costs, its value in total joint arthroplasty has not been defined. We performed this study to assess the relative incidence of VTE related admissions following TKA, the relative costs associated with care directed towards this complication, and compliance with SCIP VTE prophylaxis guidelines. From a total of 2,221 TKA procedures accomplished over a 5 year interval, we identified 121 hospital readmissions (5.4 percent). Primary readmission diagnoses were obtained from hospital coding and physician medical record documentation. Readmissions were categorised into five major complication types: 1) limited motion, 2) noninfectious wound complications, 3) bleeding complications, 4) deep infections, and 5) VTE events. VTE chemoprophylaxis was reviewed to determine the agent utilised, therapeutic level, and duration. Hospital records were assessed to determine whether additional surgeries or other procedures were accomplished and whether patients received allogeneic transfusions during their readmission. Direct costs of readmission care were obtained from hospital reimbursement records. Limited motion (18%), non-infectious wound complication (14%), surgical site infection (10%), and bleeding (10%) were the most common reasons for readmission. VTE events were less frequent (3%) and all occurred despite standard of care prophylaxis. The cost to manage bleeding, wound complications, infection, and limited motion each exceeded the cost of VTE. These results challenge the identification of VTE as a “never event.”

Hip joint preservation remains a preferred treatment option for hips with mechanically correctable pathologies prior to the development of significant secondary arthrosis. The pathologies most amenable to joint preservation are hip dysplasia and femoroacetabular impingement. These pathologies sometimes overlap. Untreated acetabular dysplasia of modest severity, if left uncorrected, always leads to arthrosis. Acetabular dysplasia is best treated by periacetabular osteotomy, usually combined with arthrotomy for management of labral pathology and associated cam-impingement if present. Pre-operative variables associated with the best long-term outcomes include less secondary arthrosis, younger age, and concentric articular surfaces.

Femoroacetabular impingement has become progressively recognised as perhaps the most common cause of secondary arthrosis. The etiology of impingement is multifactorial and includes both genetic factors and stresses experienced by the hip prior to cessation of growth. Cam impingement can be quantified by the alpha angle as measured on plain radiographs and radial MR sequences. Further, significant cam impingement is clearly associated with the development of osteoarthrosis. Treatment can be performed either by arthroscopic or open femoral head-neck osteochondroplasty. As with hip dysplasia, prognosis following treatment is correlated with the severity of preoperative secondary arthrosis but unfortunately impinging hips more commonly have some degree of arthrosis preop whereas dysplastic hips can become symptomatic with instability in the absence of arthrosis. The scientific basis for the treatment of pincer impingement is less strong. Unlike cam impingement and hip dysplasia, pincer impingement pathology in the absence of coxa profunda has not been correlated with arthrosis and so rim trimming with labral refixation is probably performed more often than is clinically indicated. Similarly, caution should be exercised when considering rim-trimming for protrusion since high central contact pressures due to an enlarged acetabular notch are not corrected by rim trimming.

Overall, joint preserving surgery remains the preferred treatment for hips with mechanically correctable problems prior to the development of significant secondary arthrosis.

Developmental dysplasia of the hip (DDH) is relatively a common condition that can lead to early arthritis of the hip. Although total hip arthroplasty is the surgical treatment of choice for these patients with end stage arthritis, some patients afflicted with DDH may present early. Acetabular osteotomy, in particular Bernese or periacetabular osteotomy (PAO as described by Professor Ganz and Jeff Mast back in 1980s) may be an option with patients with symptomatic DDH who have joint space available. PAO has many advantages. First, it is performed through a single incision (modified Smith Peterson approach) without breaching the abductor mechanism. The periacetabular fragment has, hence, excellent blood supply and avascular necrosis of the acetabular portion is not an issue. In addition, the osteotomy is so versatile allowing for great mobility of the fragment to obtain coverage even in the worst of circumstances. The osteotomy does not affect the posterior column and hence allows for earlier weight bearing. Most joint preservation surgeons in North America and Europe prefer PAO to other types of osteotomy.

The indications for PAO are a patient with symptomatic DDH who has good joint space and a congruent joint. The congruency of the joint is usually determined by the abduction views (obtained at 30 degrees abduction and neutral rotation). Although the joint space may be measured on plain radiographs, in recent years some centers have been utilising cross sectional imaging, such as dGEMERIC for evaluation of the articular cartilage, which has been shown to be a good predictor of outcome for PAO.

The majority of patients who develop hip arthritis have a mechanical abnormality of the joint. The structural abnormalities range from instability (DDH) to impingement. Impingement leads to osteoarthritis by chronic damage to the acetabular labrum and adjacent cartilage.

In situations of endstage secondary DJD, hip arthroplasty is the most reliable treatment choice. In young patients with viable articular cartilage, joint salvage is indicated. Treatment should be directed at resolving the structural abnormalities that create the impingement.

Femoral abnormalities corrected by osteotomy or increased head-neck offset by chondro-osteoplasty creating a satisfactory head-neck offset. This can safely be done via anterior surgical dislocation. The acetabular-labral lesions can be debrided and/or repaired. Acetabular abnormalities should be corrected by “reverse” PAO in those with acetabular retroversion or anterior acetabular debridement in those with satisfactory posterior coverage and a damaged anterior rim.

Often combinations of the above are indicated.

This talk will also update issues related to hip impingement and joint salvage surgery that have arisen over the past year.

Cartilage repair strategies have been applied successfully to the knee, but only recently and with limited experience to the hip. The indications for these strategies have been well defined for the knee and are defined by the diameter and depth of the defects that are mainly post traumatic and degenerative.

Viscosupplementation is an intra-articular therapy that theoretically restores the protective effects of hyaluronic acid. This therapy has been widely used for osteoarthritis of the knee with some early preliminary promising results for osteoarthritis of the hip.

Microfracture can be performed arthroscopically or as part of an open procedure. This procedure is indicated for smaller lesions less than 3cm in diameter and 1cm in depth. Widely used in the knee, the results in the hip are limited but promising. The repair tissue is however fibrocartilage.

Autologous chondrocyte transplantation can yield hyaline like repair cartilage with good mid- to long-term results in the knee. The indications are chondral defects greater than 3cm in diameter or osteochondral defects less than 1cm in depth. Its use in the hip has been limited with only a few published papers. The procedure requires two stages. The first stage which involves harvesting the cartilage can be done arthroscopically, and the second stage which involves transplantation of the cultured chondrocytes can be done arthroscopically or open.

Larger lesions greater than 3cm in diameter and 1cm in depth, can be managed by osteochondral allografts. The published mid- to long-term results for the knee have been encouraging. The results for the hip are early. To date we have performed this procedure on 16 patients. Surgical dislocation of the hip is carried out via a trochanteric osteotomy and the defect defined and trephined out. A press-fit fresh osteochondral allograft is inserted using the trephine technique. We have published our early results on a series of 8 patients with 5 good to excellent results, 1 fair results and 2 failures.

What are the data on obesity and THA risk? Which complications are elevated? If you decide on surgery, how can you minimise complications? These are timely questions because the rates of obesity are rising in the US and in many other parts of the world.

Does obesity increase risk of THA complications? Answer: yes: at least for some complications.

Complications which are increased: infection, wound healing, nerve injury; possibly: dislocation, periprosthetic fractures. The data are mixed on whether aseptic loosening and/or bearing surface wear problems are increased in the obese. Higher BMI may be offset by lower activity levels, particularly in a congruent joint such as the hip.

Outcomes of THA in obese: Lower function scores and activity scores compared to nonobese. But good pain relief and the preoperative to postoperative change in functional scores is similar to non-obese.

Is there a critical BMI threshold above which complications become unacceptable? Several studies show BMI ≥40 associated with strong risk of complications. One study from Mayo Clinic on patients with BMI ≥50 showed a 39% surgical complication rate, a 12% medical complication rate, and a high mortality rate in the several years after THA. Individualise operative decisions based on risk/benefit analysis for each patient.

If you decide to operate, how can you minimise risk? Lose weight before surgery by diet: often ineffective, but worth trying. Lose weight before THA with bariatric surgery: effective in producing weight loss, but beware of the “malnourished” obese patient

In surgery: care with patient positioning, sufficient incision length, greater exposure, avoid sciatic nerve injury, fractures, care with acetabular component positioning, extra drains in subcutaneous tissue and wound compression.

Engage patient in discussion of risks/benefits before surgery: shared decision making.

Important issues related to total hip replacement for dysplasia are: placement of the cup and bone stock; the role of femoral osteotomy, and the choice of acetabular and femoral components.

The cup can be placed at the correct or near correct anatomical level with or without a bone graft, in a high position (high hip center) or at the right level in a protruded position. All three techniques can provide adequate coverage of the cup. In the high hip position bone graft is not usually necessary to obtain cup coverage. There is however a higher rate of component loosening, a higher dislocation rate, and lengthening is limited to the femoral side. Placing the cup in a protruded position to obtain coverage does not restore bone stock for future surgery, but it does place the hip at the correct level. Placing the cup in the correct anatomical position (i.e. at the right level and not protruded) may require a structural autograft which adds to the complexity of the case. However, bone stock is restored for future surgery. In a radiographic study of 31 shelf grafts with an average follow-up of 14 years, 22 grafts had mild resorption, and 9 moderate resorption. Ten patients required cup revision, 2 at 9 years, 2 at 10 to 15 years, and 6 at over 15 years. Only 2 hips required another structural graft.

Femoral osteotomy may be used as part of the exposure for diaphyseal shortening or for derotation of excessive anteversion. The osteotomy is carried out in the sub-trochanteric region and may be oblique, step-cut or transverse. Fixation of the osteotomy is achieved via the stem, a plate, or a cortical strut.

Cementless components are usually used because of the relatively young age of this patient population. Small components may be necessary. On the femoral side, the stem should be straight or modular so excessive anteversion can be neutralised.

Protrusio acetabuli can be either primary or secondary. Primary or idiopathic protrusio is a rare condition of unknown etiology. Secondary protrusio may be associated with rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, osteomalacia, trauma and Paget's disease. Challenges in surgery include lack of bone stock, deficient medial support to the cup, difficulty in dislocating the femoral head, and medialisation of the hip joint center. Several surgical techniques have been described: use of cement alone without bone graft; morsellised impacted autograft or allograft with a cemented cup; metal cages, reinforcement rings, and solid grafts.

We describe our technique of impaction grafting using autologous bone and a cementless porous-coated hemispherical cup without the use of acetabular rings or cages in patients with an average age of 46 years. Protrusion was graded depending on distance of medial wall from Kohler's line as mild (1–5mm medial), moderate (6–15mm medial) and severe if it was more than 15mm medial to the Kohler's line. All patients were operated in the lateral position using a modified Hardinge's anterolateral approach. Adductor tenotomy may be required in cases of severely stiff hips. After careful dislocation of the femoral head, it was sectioned in situ into slivers to facilitate obtaining the graft. The periphery was reamed and care was taken to preserve the membrane lining the floor of the defect. Morsellised graft was impacted with hemispherical impactors and the trial cup 1–2mm larger than the last reamer placed in the desired position. The final socket was then inserted. Femoral preparation was performed in routine fashion.

The mean preoperative Harris hip score of 52 improved to 85 points at a mean follow up of 4 years. The average acetabular inclination angle was 42 degrees. Our results have shown incorporation of the graft in all cases. There was no evidence of progression of the protrusio or cup loosening in any of the cases. Thus far, our hips have not shown osteolytic lesions. The technique described is a satisfactory biological solution of restoring bone stock particularly in young and middle-aged patients.

Significant hip osteoarthritis has been reported in 8–28% of patients with Down Syndrome. The prolonged life expectancy of these patients has allowed many of them to become disabled by their hip arthritis with the need for hip replacement.

We have been able to perform a multi-center study evaluating total hip replacement in patients with Down Syndrome. Twenty patients (25 hips) with Down Syndrome underwent primary THA at a mean age of 35 years old with a mean 105 month follow-up. Cementless acetabular fixation with screws were used in all cases and all but one femoral component was cementless. Constrained liners were used in 8 cases to enhance stability. Five hips required revision surgery: two femoral components (one for periprosthetic fracture and one for aseptic loosening), two acetabular components (one for recurrent dislocation and one for wear with metallosis), and one hip required a two-stage revision for infection. Other than the hip revised for loosening, no other hip had radiographic evidence of loosening. The mean Harris Hip score improved from 42 points preoperatively to 83 points at final follow-up.

THA is a reliable surgical intervention in patients with Down Syndrome and symptomatic coxarthrosis. These patients and their families have been tremendously satisfied with this procedure.

Arthritis of the hip is a relatively common problem in patients with neuromuscular disorders due to muscle imbalance around the hip from weakness, paralysis, contractures and spasticity. Neuromuscular disorders such as cerebral palsy, Parkinson's disease, poliomyelitis, previous cerebrovascular accident (CVA) and Charcot arthropathy have been considered by many to be relative contraindications to total hip arthroplasty (THA). The presence of certain anatomic abnormalities (excessive femoral anteversion, acetabular dysplasia, leg length discrepancy (LLD) and coax valga) and significant soft tissue contractures, muscle imbalance, and muscular weakness make THA a challenging surgical procedure in this patient population, and can predispose to dislocation and poor functional outcome following surgery. THA can, however, result in substantial pain relief and functional improvement in patients with significant hip arthritis and neuromuscular disorders, and can be safely performed, provided certain technical considerations are addressed.

The patient's motor strength and functional status (ambulatory vs. “sitter”) should be carefully assessed pre-operatively, since both of these factors may affect the choice of surgical approach and component position. Significant soft tissue contractures should be released at the time of surgery. Although these can be frequently performed “open”, percutaneous adductor tenotomy is occasionally necessary for patients with significant adduction contractures. Patients requiring significant soft tissue releases may benefit from 6 weeks of bracing to allow soft tissues to heal appropriately and minimise risk of dislocation during this period of time.

Use of modular femoral components that allow for correction of excessive femoral anteversion, should be considered in patients with coexistent dysplasia and neuromuscular disease (i.e. CP or polio). Large femoral head components should also be considered in patients with increased risk factors for dislocation. Despite their obvious theoretical advantages, the use of large head metal on metal THAs should be used with extreme caution in view of growing concerns about these devices. Although constrained acetabular liners are associated with an increased risk of mechanical failure, their use should be strongly considered in patients with significant motor weakness or major soft tissue deficiencies. Meticulous soft tissue closure of the capsule of the hip is recommended, especially when performing THA through a posterior approach. Patients with neuromuscular disorders associated with spasticity and involuntary movements need to be optimally treated medically prior to and indefinitely after THA.

There are limited reports of outcomes following THA in patients with neuromuscular disorders, however some generalisations based on underlying diagnosis can be made. Patients with cerebral palsy and polio frequently have acetabular dysplasia, excessive femoral anteversion and LLD, and although durability does not seem to be a major concern, dislocation and instability is relatively common and needs to be addressed. Durability and instability do not appear to be major concerns in patients with Parkinson's disease, however, these patients have frequent medical complications perioperatively and have deterioration in function over time due to the progressive nature of their underlying disorder. Patients with previous CVA also appear to have acceptable durability and dislocation risk, but are at high risk of developing heterotopic ossification postoperatively. Patients with Charcot arthropathy or myelodysplasia are at high risk of instability and appear to have limited functional improvement following THA. As a result, the consensus of opinion is that THA is contraindicated in patients with Charcot arthropathy and myelodysplasia.

Hip fusion used to be a common procedure in children and young adults, but it is now exceedingly rare.

My results of hip fusion takedown more than 20 years ago were quite acceptable. Of 20 cases, 88% achieved more than 90 degrees of flexion and 75% stopped limping by the end of one year. The elderly would revert to limping when tired.

As no simple hips are currently fused, the results of hip fusion takedown in the last 20 years are very much inferior. Of 28 cases, limp is absent in 20%, mild in 12% and severe in 68%. Range of motion is acceptable with 80% eventually achieving more than 90 degrees of flexion.

There are complications, but these are quite manageable. The aseptic loosening rate is small and the longevity is high. Current implants, therefore, can easily handle the hip fusion takedown.

As the incidence of limp is prohibitively high, additional techniques to reinforce the hip abductors either concurrently or more likely as a secondary procedure as suggested by Whiteside should be learned by all those proposing to carry out hip fusion takedown.

This session will present a series of challenging and complex primary and revision cases to a panel of internationally respected hip arthroplasty experts. The primary cases will include challenges such as hip dysplasia, altered bony anatomy and fixation challenges. In the revision hip arthroplasty scenarios issues such as bone stock loss, leg length discrepancy, instability and infection will be discussed. This will be an interactive case based session that at its conclusion should leave the attendee with a more thorough approach to these challenging issues.

The elements of my routine pre-operative planning include skin and scar assessment, the limb length (physical exam and radiographic assessments), the socket type, the stem type, and radiographic templating. Blood management is rarely an issue for primary total hips today and I generally do not recommend pre-operative autologous donation. I currently use a low molecular weight heparin for venous thromboembolic prophylaxis for most all patients. All of my patients have pre-operative medical clearance from a hospital intensivist.

A press-fit modular cementless socket is my “workhorse”, although I occasionally use supplemental fixation with spikes (low bone density) or screws (shallow or otherwise deficient hemisphere). Cemented fixation is reserved for hips with radiation necrosis. I use a dual-offset tapered cementless stem in most cases but will use a modular stem in dysplastic, post-traumatic, or severely osteoporotic femurs.

I template every case. My goals are to determine component sizes - “the part inside the bone” and improve the biomechanics of the hip – “the part outside the bone”. Sizing is relatively straightforward. For the socket, I use the teardrop and the superior bony edge as landmarks for size and position. I use a Johnson's lateral view radiograph to assess socket version and anterior osteophytes. With a tapered stem, proximal fit on the AP radiograph is the goal and the stem does not need to be canal filling. For the neck resection, I reference off the lesser trochanter.

Medialisation of the hip center of rotation (COR) decreases the moment arm for body weight; increasing the femoral off-set lengthens the lever arm for the abductor muscles. These changes in hip biomechanics have a double benefit: a reduction in required abductor forces and lower joint reaction forces. There is accumulating clinical evidence that such favorable alterations in biomechanics can improve clinical outcomes and reduce wear. Higher femoral offset has been associated with greater hip abduction motion and abductor muscle strength. In two independent studies, higher femoral offset has been associated with a significant reduction in polyethylene wear.

The traditional arthroplasty goal has been to re-create the offset of the operated hip. In an analysis of 41 patients with one arthritic hip and one clinically and radiographically normal hip (Rolfe et al., 2006 ORS), we found that the horizontal femoral offset of the arthritic hip was, on average, 6mm less than that of the normal, contralateral hip. Considering this, and with medialisation of the COR, is it reasonable to make the femoral offset a few millimeters greater than that pre-op. With modular trial components, final offset and limb-length adjustments are made intra-operatively by assessing soft tissue tension, joint stability and range of motion.

Applying these principles in a consecutive series of 40 hips, the hip center of rotation was medialised by 5.6mm and the horizontal femoral offset was increased by an average of 9.5mm, being larger than the normal, contralateral hip by an average of 5.2mm. This combination increased the net biomechanical advantage (NBA) of the diseased hip to an average of 12.5% more than the normal, contralateral hip. The increase in femoral offset is compensated for by medialising the center of rotation. The average lateralisation of the proximal femur of 3.9mm did not cause trochanteric bursitis or other pain. When the offset is right, soft tissue tension can be maintained without over-lengthening. In this series, 2.9mm average lengthening resulted in the reconstructed limb being an average of 1.1mm shorter than the normal side.

In the early days of total hip arthroplasty, the discussion of surgical approaches centered on issues related to obtaining optimum exposure for accurate insertion and fixation of implants and appropriate restoration of hip kinematics. More recently, attention has been directed to those aspects of exposure that appear to be associated with rapid recovery, shorter lengths of stay, less pain and minimal gait disturbance. The role of less invasive (“MIS”) exposures in achieving these outcomes has been sharply and extensively debated. Currently, the Direct Anterior Approach is being used by an increasing number of surgeons to address these outcomes. The purpose of this presentation is to discuss the relationship of total hip surgical approaches to peri-operative morbidity, rate of functional recovery, length of hospital stay and ultimate lower extremity function.

Many factors affect the quality and rate of recovery from THA surgery. These include: 1) patient characteristics; 2) implant type; 3) surgical exposure and technique; and 4) peri-operative management. Numerous reports suggest that patient selection and effective peri-operative management have the greatest impact on the rate of recovery. The quality of the arthroplasty outcome is related to the accuracy with which the procedure is performed, regardless of the surgical approach used. Available evidence strongly suggests that the quality of the surgical technique used to perform a THA is a much more important determinant of outcome than the surgical approach used.

The mean age of patients with osteonecrosis reported in series in our literature is 38 to 53. Thus, performing a total hip replacement on a patient who would need a procedure to last 40–45 years is a concern. Patients with osteonecrosis of the hip require some type of surgical treatment. Without treatment, a large majority of femoral heads in patients even with Ficat stage I osteonecrosis will collapse or become symptomatic. A common scenario is a patient who first presents to the orthopaedic surgeon with severe arthritis secondary to osteonecrosis in one hip and a normal appearing radiograph on the asymptomatic contralateral side. Performing a total hip on the severe arthritic hip is usually not debated. A MRI will commonly show Ficat stage I osteonecrosis on the asymptomatic contralateral hip. Some method of core decompression is a reasonable choice if it is non-steroid induced, small more medially positioned lesion, but not for other Ficat stage 1 lesions or those with more advanced stages. The problem is convincing the patient to have anything done when they are asymptomatic. Because results with total hip replacement for patients with osteonecrosis of the hip have significantly improved, most patients with a symptomatic hip prefer arthroplasty as treatment. Arthroplasty has become the predominant surgical treatment for osteonecrosis of the hip in the United States. Eighty-eight percent of procedures performed on 6,400 patients with osteonecrosis in 2008 reported in the Nationwide Inpatient Sample Database of the hip were total hip replacements. From 16 years earlier, the number of procedures performed had almost doubled and the percentage use of arthroplasty as the performed treatment had increased by 13%. I expect both numbers will continue to increase.

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty.

A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism.

Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thromboses, three proximal deep venous thromboses, and five pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%.

Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provides a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature.

Hip resurfacing using metal-on-metal bearings has a number of purported advantages over traditional total hip replacement in the young, active patient. Males in particular can benefit from the bone preservation, stability, and higher activity levels seen with this procedure. As more is learned about the factors affecting long-term outcome of hip resurfacing, component position has emerged as one major predictor of success.

Given a well-selected patient, and a well-designed device, acetabular positioning is perhaps the most important determinant of long-term survivorship in hip resurfacing. One feature of resurfacing socket design which has not been widely disseminated is the sub-hemispheric arc of the bearing surface. While the outer circumference of the socket represents a complete hemisphere, and radiographic evaluation may assume that the apparent socket angle is satisfactory, the actual bearing is less than a hemisphere, so that the true abduction of the bearing is considerably more vertical. This important fact leads to excessive bearing inclination, edge loading, and all that follows, including runaway wear, metallosis, ALVAL, and pseudotumors.

Inadequate socket anteversion can expose the psoas tendon to abrasion and tendonitis. Too much acetabular anteversion, especially when combined with increased femoral neck anteversion, can result in an overall decrease in bearing contact area, and excessive wear.

Femoral component positioning is critical in the prevention of femoral neck fractures, which are a chief cause of early failure. Varus placement increases the tensile stresses on the superior femoral neck. Excessive valgus threatens notching. Both increase femoral neck fractures.

Sufficient malposition will ultimately result in edge loading. Edge wear is incompatible with fluid film lubrication, the key to longevity of these bearings.

Cemented total hip arthroplasty has become an extremely successful operation with excellent long term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed.

Cementing the acetabular side should include preservation of the transverse acetabular ligament and clear identification of the medial wall. Medialisation and deepening of the socket are important at reaming, to ensure a containment of the cup. The contact of the cup to cancellous bone should be maximised. Either smaller reamers or 4–6mm anchoring holes can be drilled to the superior sclerosis. Smaller defects can be curettage, while larger ones might require cancellous bone grafting. Of major importance is the thoroughly pulsatile jet lavage with saline to irrigate the cancellous bone bed, to reduce fat and blood lamination. After final irrigation, before cementation, dry sponges are slightly impacted into the cavity, to dry it out. Cementation usually requires 40g of high viscosity bone cement. Immediate pressurisation of the cement into the bone bed should start after a general application time in our institution between 2.5 to 3 minutes after mixing; with either a sterile glove filled with a sponge or designated company specific pressuriser. Sustained pressurisation should be done for 1 minute. The original cup should be 3–4mm smaller than the last reamer, to ensure circumferential cement mantle. Insertion principle includes medialisation first, followed by gradual angulation of the cup. In appropriate position, a balled pressuriser maintains pressure without further moving of the implant, until cement hardening. Remnant cement can be removed with osteotomes, while remaining osteophytes should be flush with implant.

Femoral Side: First the fossa pyriformis should be clearly identified, including the posterolateral entry point of the prosthesis. The femoral neck cut is usually 1.5–2cm above the minor trochanter, based on the preoperative planning and implant type. Opening of the canal is done with an awl or osteotome, followed by any blunt tipped instrument, to follow the intramedullary direction. A box osteotome opens the lateral portion of the femoral neck, gently to preserve as much cancellous bone as possible. Sequential broaching follows carefully and according to the planning, to ensure preservation of 2–3mm cancellous bone for interdigitation. Some systems might require over-broaching by one size. Trialing is done with the broach. Following, irrigation using a long nozzle pulsatile lavage, reduces the chance for fat embolism. A cement restrictor is then placed 1.5–2cm distal to the tip of the stem, to ensure an adequate cement mantle distally. A second complete pulsatile irrigation of the canal follows, to minimise bleeding, followed by a dry sponge. Cement mixing is vacuum based in the meantime, usually 60–80g. We prefer the use of low dose antibiotic laden cement in our set up. Two to three minutes after mixing, the cement is applied rapidly in a retrograde technique with a cement gun, placing the nozzle tip against the cement restrictor. The gun is “pushed” out during the application, rather than being withdrawn from the canal. Proximal pressurisation is first done by thumb, then with a proximal seal for 1 minute. The stem is inserted slowly using steady manual pressure, in the center of the cement mantle, however, should never be impacted. The stem is aligned with the previously defined lateral entry point and is held in position until the cement hardens. The desired outcome is a cement interdigitation into cancellous bone for 2–3mm and an additional mantle of 2mm pure cement.

Dual mobility components for total hip arthroplasty provide for an additional articular surface, with the goals of improving range of motion, jump distance, and overall stability of the prosthetic hip joint. A large polyethylene head articulates with a polished metal acetabular component, and an additional smaller metal head is snap-fit into the large polyethylene. New components have been released for use in North America over the past three years. In some European centers, these components are routinely used for primary total hip arthroplasty. However, their greatest utility may be to manage recurrent dislocation in the setting of revision total hip arthroplasty. Several small retrospective series have shown satisfactory results for this indication at short- to medium-term follow-up times. However, there are important concerns with polyethylene wear, late intra-prosthetic dislocation, and the lack of long-term follow-up data. These components are an important option in the treatment of recurrent dislocation in younger patients, revision of failed metal-metal resurfacing, and salvage of failed constrained liners. Until further long-term results are available, caution is advised in the routine use of dual mobility components in primary or revision total hip arthroplasty.

Over a four year period of time, 142 consecutive hip revisions were performed with the use of an extended proximal femoral osteotomy. Twenty patients had insufficient follow-up or were followed elsewhere and were excluded from the review. The remaining 122 revisions included 83 women and 39 men. Average age at time of revision was 63.8 (26–84) years. Indications for revision were aseptic loosening (114), component failure (4), recurrent dislocation (2), femoral fracture (1) and second stage re-implantation for infection (1).

The extended proximal femoral osteotomy gave easy access to the distal bone-cement or bone prosthesis interface in all cases. It allowed neutral reaming of the femoral canal and implantation of the revision component in proper alignment. Varus remodeling of the proximal femur secondary to loosening was handled with relative ease implementing the osteotomy. Average time from the beginning of the osteotomy procedure to the complete removal of prosthesis and cement was thirty-five minutes. There were no non-unions of the osteotomised fragments at an average post-op follow-up of 2.6 years with no cases of proximal migration of the greater trochanteric fragment greater than 2mm, there was evidence of radiographic union of the osteotomy site in all cases by 3 months. Stem fixation with bone ingrowth was noted in 112 (92%) of 122 hips, stable fibrous fixation was seen in 9 (7%) and 1 stem was unstable and was subsequently revised. However, there was an incidence of 7% perforation rate of the femoral canal distal to the osteotomy site during cement removal. This was most prevalent where there was greater than 2cm of cement plug present which was well bonded. When OSCAR was used instead of hand tools or power reamers, there were no perforations in 51 cases. There has been no failure of fixation with fully porous coated stems inserted in the canals where OSCAR had removed cement. Also, the use of OSCAR has allowed us to shorten the osteotomy, thus allowing a longer, intact isthmus to remain so that shorter stems can be used. We highly recommend the use of OSCAR in conjunction with the extended osteotomy for removal of well-fixed distal cement beyond the extended osteotomy site.

Removal of a long cement mantle that is well fixed distally during total hip revision can be a technically demanding procedure with many potential complications.

The extended femoral slot offers a technique that allows direct visualisation during cement removal while maintaining an intact femoral tube.

The proximal end of the femur is exposed taking care to remove all soft tissue that might prevent removal of the loose femoral component. The loose femoral component is removed using thin osteotomes and a femoral extraction device as needed. The proximal cement mantle is removed under direct vision to the level of the flare of the greater trochanter. The outside of the femoral shaft below the flare of the greater trochanter is exposed by splitting the vastus lateralis. Pre-operative measurements are imperative to determine the distal level of the cement mantle. An extended rectangular slot approximately 1.5cm wide is made in the anterolateral aspect of the femur starting just below the flare of the greater trochanter and continuing to the level of the distal aspect of the cement mantle. This can be done using a pencil-tipped burr on the Midas Rex or an oscillating saw. The rectangular strip of bone is removed and saved to be replaced and secured with cerclage technique during closure.

The entire cement mantle is removed under direct vision using osteotomes and other cement removing instruments as needed. The opened femoral canal is then reamed to accept a new revision femoral component.

The extended femoral slot is a safe and effective technique for cement removal during revision hip arthroplasty in selected cases. It is not used when there is varus deformity of the proximal femur but in selected cases is an alternative to the extended greater trochanteric osteotomy and preserves the circumference of the femoral tube.

Two-staged revision including removal of all components is a common approach for treatment of infected THA. However, removal of well-fixed femoral stems can result in bone loss and compromised fixation. An alternative in selected cases is partial two-stage exchange, in which the well-fixed femoral stem is left in situ, only the acetabular component is removed, the joint space is debrided thoroughly, a spacer is placed, IV antibiotics are administered during the interval, and delayed reimplantation is performed.

We recently reported our results using the technique of partial two-stage exchange of infected THA. From 2000 through January 2011 in 19 patients with infected THA treated with partial two-stage exchange including complete acetabular component removal, aggressive soft tissue debridement, retention of the well-fixed femoral stem, placement of an antibiotic-laden cement femoral head on the trunnion of the retained stem, postoperative course of antibiotics, and delayed reimplantation. Indications for this treatment included those patients whose femoral component was determined to be well fixed and its removal would result in significant femoral bone loss and compromise of future fixation. During the study period, this represented 7% (19 of 262) of the patients whom we treated for a chronically infected THA. Minimum follow-up was 2 years (mean, 4 years; range, 2–11 years). None of the 19 patients in this series were lost to followup. We defined failure as recurrence of infection in the same hip or use of long-term suppressive antibiotics.

Two patients (11%), both with prior failure of two-staged treatment of infection, failed secondary to recurrence of infection at an average of 3.3 years. There were no patient deaths within 90 days. Postoperative Harris hip score averaged 68 (range, 31–100).

As 89% of patients in this series were clinically free of infection at a minimum of 2 years, we believe partial two-stage exchange may represent an acceptable option for patients with infected THA when femoral component removal would result in significant bone loss and compromise of reconstruction. Further study is required on this approach.

Corrosion at metal/metal modular interfaces in total hip arthroplasty was first described in the early 1990's, and the susceptibility of modular tapers to mechanically assisted crevice corrosion (MACC), a combination of fretting and crevice corrosion, was subsequently introduced. Since that time, there have been numerous reports of corrosion at this taper interface, documented primarily in retrieval studies or in rare cases of catastrophic failure.

We have reported that fretting corrosion at the modular taper may produce soluble and particulate debris that can migrate locally or systemically, and more recently reported that this process can cause an adverse local tissue reaction. Based on the type of tissue reaction and the presence of elevated serum metal ion levels, this process appears quite similar to adverse local tissue reactions secondary to metal on metal bearing surfaces. While modularity in THR has demonstrable clinical benefits, modular junctions increase the risk of corrosion and the types of adverse soft tissue reactions seen in patients with accelerated metal release from metal-on-metal bearing THRs.

The reconstructive hip surgeon is commonly faced with complex cases where severe bone loss makes conventional revision techniques difficult or impossible. This problem is likely to increase in future, as there is a good correlation between the degree of bone loss seen and number of previous total hip operations. In such situations, one alternative is the use impaction allografting with cement. This has captured the attention of the orthopaedic community because of its potential for reconstituting femoral bone stock.

The first clinical reports of impaction allografting on the femoral side were in relation to revision with cementless stems. The use of morsellised bone with cement on the femoral side was first reported by the Exeter group. The great enthusiasm with which this technique has been received is related to its biological potential to increase bone stock. The rapid revascularisation, incorporation and remodelling of morsellised compacted cancellous allograft differs dramatically from structural allografting where bone ingrowth usually is limited to 2–3mm. Histological evidence for bony reconstitution has been presented from postmortem retrievals, and from biopsies at the time of trochanteric wire removal.

The size of the bone chips used as morsellised allograft is important. The graft behaves as a friable aggregate and its resistance to complex forces depends on grading, normal load and compaction. It is recommended that particles of 3–5mm in diameter make up the bulk of the graft. A bone slurry, such as that produced by blunted bone mills, or by the use of acetabular reamers or high speed burrs would not give satisfactory stability. A wide range of particle sizes is recommended in order to achieve the greatest stability. Future considerations will include the potential for either adding biomaterials to the allograft, or ultimately substituting it completely.

A satisfactory cement mantle is required to ensure the longevity of any cemented stem. The primary determinant of cement mantle thickness is the differential between the graft impactors and the final stem. All femoral impaction systems require careful design to achieve a cement mantle that is uninterrupted in its length and adequate in its thickness.

The technique of impaction allografting on the femoral side was first and most successfully reported using a highly polished stem with a double tapered geometry and no collar. It is thought to be ideal for this technique as it can subside within the cement mantle, thus generating hoop stresses on the cement which creeps, potentially maintaining physiological loads on the supporting bone. The extension of this technique to other stems has led to some controversy. Confounding factors such as surgical technique, the impaction system available, the type and size of allograft bone used, and the extent of the pre-operative bone loss, will undoubtedly continue to influence such comparisons. It appears that the exact stem configuration may not be as critical as its surface finish, the amount of graft impaction possible and the cement mantle produced.

Impaction allografting is the only technique currently available that reverses the loss of bone stock seen in a revision hip arthroplasty. Moreover, this technique does not sacrifice host tissue, and could facilitate further surgery. Impaction allografting, performed with great attention to detail using appropriate equipment, represents an exciting reconstructive solution for contained femoral defects. Its role in larger and combined defects remains open to scrutiny. Careful observation and cautious optimism are necessary as further refinements may well improve the predictability of the clinical results and expand the indications for this important addition to the armamentarium of the revision surgeon.

The S-ROM stem is distally circular canal filling with thin sharp flutes which engage the endosteal cortex. The rotational stability produced by this is 37 Nm, which exceeds the service loads on the hip of 22 Nm. The distal canal fill prevents varus and valgus displacement. The porous-coated proximal sleeve provides resistance to vertical sink and also excludes the distal stem from the effective joint space.

The primary stem is straight and the long stem is bowed with a 15 degrees anteversion twist proximally. The neck comes in lengths from 30 to 46mm with varying offset. The sleeves come in variable size and geometry.

The stem choice in revision surgery is based on the Scoot Diamond Classification. Type 1 (this is going to be easy) is a primary stem. Type 2 (this is going to be difficult) implies diaphyseal bone loss and will require a long stem. Type 3 (Oh My God), implies more than 70mm of completely missing proximal femur and will require a structural allograft cemented to the sleeve.

Cementless stem fixation is a widely used method of stem revision in North America and elsewhere in the World. There is abundant literature in its support. Most of the reports from 1985 to 2005 related to proximally or extensively porocoated designs, the former falling into disfavor with time because of unpredictable outcomes. With few exceptions (eg S-ROM) the modularity of these designs was limited to the head/neck junction. But this generation of designs was associated with some issues such as insertional fractures, limited control of anteversion (and risk of dislocation), limited applicability in the setting of severe bone loss (Paprosky Type 4 osteolysis or Vancouver Type B3 periprosthetic fracture), as well as ongoing concern relating to severe proximal stress shielding.

In the past decade we have seen the mounting use of a new design concept: tapered fluted titanium stems (TFTS), which incorporate the advantages of titanium (for less flexural rigidity), conical taper (for vertical taper-lock stability), longitudinal ribs and flutes (for rotational stability), and surface preparation which attracts bone on growth for long term fixation.

Four consecutive reports from our center have documented the superiority of the TFTS in our hands, with encouraging outcomes even when dealing with severe bone loss or periprosthetic fractures. There is an increasing body of other literature which reports a similar experience.

Furthermore, with increasing experience and confidence in this design, we now use a monoblock or non-modular design in greater than 95% of cases in which a TFTS is indicated at our center. This circumvents the potential drawbacks of stem modularity, including taper corrosion and taper junction fracture.

The use of tapered, fluted, modular, distally fixing stems has increased in femoral revision surgery. The goal of this retrospective study was to assess mid-term to long-term outcomes of this implant in femoral revision with bone-loss. Seventy-one hips in 70 patients with a mean age of 68.5 years were followed for an average of 10 years. Preoperative HHS averaged 50 and improved to an average of 87 postoperatively. Seventy-nine percent hips had Paprosky type 3A, 3B or 4 bone-loss and 44% had an associated proximal femoral osteotomy. All stems osseointegrated distally (100%). Two hips subsided >5mm (mean 8mm) but achieved secondary stability. Sixty-eight percent hips had evidence of bony reconstitution and 21% demonstrated diaphyseal stress- shielding. One stem fractured at its modular junction and was revised with a mechanical failure rate of 1.4%. Distal fixation and clinical improvement were reproducibly achieved with this stem design.

Massive proximal femoral bone loss can be a complex problem, despite various modern technical and implant solutions. Due to inadequate bone stock and missing proximal fixation possibilities, including larger segmental osseous defects, the use of a mega prosthesis might become necessary. Coverage of the segmental bone loss in combination with distal fixation, can be achieved in either cemented or non-cemented techniques. Some implant types allow for additional fixation of the gluteal muscles, attached with non-absorbable sutures or synthetic mesh grafts. Although first reports about partial or even complete femoral replacement are available since the 1960's, larger case series or technical reports are rare within the literature and limited to some specialised centers. Most series are reported by oncologic centers, with necessary larger osseous resections of the femur.

The final implantation of any mega prosthesis system requires meticulous planning, especially to calculate the appropriate leg length of the implant and resulting leg length. Combination of a posterior hip with a lateral knee approach allows for the enlargement to a total femur replacement, if necessary. The lateral vastus muscle is detached and the entire soft tissues envelope can be displaced medially. After implant and cement removal, non-structural bone might be resected. Trial insertion is important, due to the variation of overall muscle tension intraoperatively and prevention of early or late dislocation. Currently the use of proximal modular systems, including length, offset and anteversion adaption, became the technique of choice for these implant systems. However, just very few companies offer yet such a complete system, which might also be expanded to a total femur solution.

We were able to evaluate our Endo-Klinik results of total-femur replacements within 100 consecutive patients in non-infected cases, after a mean follow up time of five years. There we “only” 68% patients without complications, main complications included: 13% revealed a deep infection; dislocation was found in 6%, material failure and consequent breakage in 3%, persistent patellar problems in 2% and finally 1% with peroneal nerve palsy.

These results show that a total-femur replacement is associated with a high complication rate, even in non-infected patient cohorts.

Polyethylene and femoral head exchange for wear or osteolysis is a common operation. The difficulty lies in the facts that wear and osteolysis are difficult to measure, wear does not always correlate with osteolysis, catastrophic failure (wear through, loosening, or fracture) is difficult to predict, and these problems are usually asymptomatic.

I currently recommend this procedure when complete wear through of the polyethylene is present or impending, when the patient has obvious wear and symptoms, or if there is a rapidly enlarging osteolytic lesion.

The surgical goals focus on management of debris generation and management of the osteolytic lesion. A third goal becomes avoidance of the know complications of this procedure. Management of debris generation basically involves modernising the head and polyethylene. Management of the osteolytic lesion includes debridement and when possible grafting. By far the most common complication after this procedure is dislocation. Prevention of dislocation should be accomplished by patient education, use of larger heads when possible, and capsular repair.

Prerequisites to perform this procedure are a replacement liner of adequate thickness that can be locked or cemented in place. The acetabular component must be stable. Lastly the component must be properly oriented to minimise both wear and dislocation.

Metal-on-metal liner conversion to metal-on-poly is becoming more common. Since patient satisfaction with THA is high, MoM patients may unknowingly minimise their symptoms because they are minor compared to the symptoms before surgery. The patient history should include specific questions about groin pain, swelling, hip noise, and asking the patient if they notice their hip on a daily basis. Patient symptoms, osteolysis and a pseudotumor are indications for modular conversion. Radiographically stable, well-oriented components that can accept a polyethylene liner are requirements for a successful conversion.

Hemispheric, porous-ingrowth revision acetabular components (generally with multiple screw fixation) have demonstrated versatility and durability over 25 years. Jumbo cups (minimum diameter of 62mm in women, 66mm in men, or 10mm larger than the normal contra-lateral acetabulum) are utilised in the majority of revisions with acetabular bone loss, with or without bone grafting, or other augmentation. The popularity of jumbo cups is due to their relative ease of use and the reliability of the result. With up to 20 year follow-up, and failure defined as cup revision for aseptic loosening or radiographic evidence of loosening, implant survival was 97.3% (95% confidence interval [CI], 89.6% to 99.3%) at ten years and 82.8% (95% CI, 59% to 97.6%) at fifteen years. Instability is decreased in association with larger diameter bearings. Revisions associated with wear of non-crosslinked polyethylene increased in the second decade. Cross-linked polyethylene and ultra-porous materials will likely increase both the durability and the utility of jumbo cups.

Allograft materials have been the mainstay in addressing bone deficiencies in knee and hip replacement and revision surgery for decades because of the associated donor site morbidity of autografts. Bone graft substitutes have been developed to address allograft issues including potential contamination, disease transmission, and availability. Although non-autogenous products have no osteogenic potential, they do have a variable degree of osteoinductive and osteoconductive properties.

Unfortunately, there are limited reports regarding use of bone graft substitutes for use in total hip and knee arthroplasty. Bone graft substitutes have most frequently been used as an “extender”, in combination with morsellised allograft, to fill cavitary defects. Incorporation of this bone graft substitute and morsellised allograft combination appears to occur incompletely. Stable implant fixation appears to be a prerequisite for incorporation of bone graft substitutes, as these cannot be relied upon for structural support. Although bone graft substitutes appear to perform satisfactorily as “fillers” for contained cavitary bone defects, ultraporous metal augments have become the preferred method of providing structural support for some defects. In view of their substantial cost, high quality clinical, radiographic and retrieval data regarding performance of bone graft substitutes is needed.

Highly porous metal surfaces have transformed acetabular revision surgery by providing (1) enhanced friction which potentially provides greater primary fixation, (2) enhanced bone ingrowth potential, (3) enhanced screw fixation options. These characteristics have led many surgeons to use these devices routinely in acetabular revision and have led to an expansion of the indications for porous uncemented hemispherical cups in acetabular revision. Mid-term results suggest that the historical indications for hemispherical cups in revision surgery can be moderately expanded with some implants with these characteristics. In a recent study of 3448 revision total hip arthroplasties, we found porous tantalum cups had a statistically lower revision rate than other materials/designs. Highly porous metals also have provided the options of metal augments to fill selected bone defects—which can both enhance cup fixation and manage bone loss simultaneously. A number of different highly porous metals are now available, and how each will perform is not yet known.

Pelvic discontinuity with associated bone loss is a complex challenge acetabular revision surgery. Reconstruction by the use of ilio-ischial cages combined with trabecular metal acetabular components and morsellised bone (the component-cage technique) is a relatively new method of treatment. The trabecular cup provides a good environment for bone graft remodeling and eventual bone or fibrous ingrowth. The cage protects the trabecular metal cup until stabilisation occurs. The cage not only protects the cup but places the articulating center at the correct level.

We reviewed a consecutive series of 32 cases of acetabular revision reconstructions with pelvic discontinuity who had been treated by the cup-cage technique. The mean follow-up was 38 months (24.0 to 68.0). Failure was defined as a migration of a component of >5mm.

In 29 hips there was no clinical or radiological evidence of loosening at the last follow-up. The Harris hip scores improved significantly from 44.6 (sd 10.4) to 78.7 (sd 10.4) points (p<0.001).

In three hips (11.5%) the construct migrated at one year after surgery. The complications included two cases of dislocations, one of infection and one of partial palsy of the peroneal nerve. Our findings indicated that the treatment of pelvic discontinuity by the component-cage construct is a reliable option.

Stabilisation of a pelvic discontinuity with a posterior column plate with or without an associated acetabular cage sometimes results in persistent micromotion across the discontinuity with late fatigue failure and component loosening. Acetabular distraction offers an alternative technique for reconstruction in cases of severe bone loss with an associated pelvic discontinuity.

We describe the technique of acetabular distraction with porous tantalum components and evaluate its survival, function and complication rate in patients undergoing revision surgery for chronic pelvic discontinuity.

Between 2002 and 2006, we treated 28 patients with a chronic pelvic discontinuity acetabular reconstruction using acetabular distraction. A porous tantalum elliptical acetabular component was used alone or with an associated modular porous tantalum augment in all patients. Three patients died and five patients were lost to follow-up before two years. The remaining twenty patients were followed semiannually for a minimum of two years (average, 4.5 years; range, 2–7 years) with clinical pain and walking scores as well as radiographic evaluation for loosening, migration or failure.

In the remaining twenty patients available for follow-up, one patient did require re-revision for aseptic loosening. Fifteen patients remained radiographically stable at last follow-up. Four patients had early migration of their acetabular component but thereafter remained radiographically stable and clinically asymptomatic. The average improvement using the modified Merle d'Aubigne – Postel pain and ambulation score was 6.6 (range, 3.3–9.6). There were no postoperative dislocations; however, we did encounter one infection, one vascular injury and one bowel injury.

In this series, the use of acetabular distraction with porous tantalum components provides a biologic alternative to cage constructs with more predictable clinical results (average follow-up 4.5 years) for reconstruction of severe acetabular defects with associated pelvic discontinuity.

The presentations to be discussed by the panel are: 1.) No Increased Risk of Knee Arthroplasty Failure in Metal Hypersensitive Patients: A Matched Cohort Study; 2.) Knee Arthrodesis is Most Likely to Control Infection and Preserve Function Following Failed 2 Stage Procedure for Treatment of Infected TKA: A Decision Tree Analysis; 3.) Does Malnutrition Correlate with Septic Failure of Hip and Knee Arthroplasties?; 4.) Diagnosing Periprosthetic Joint Infection: The Era of the Biomarker Has Arrived; 5.) Are Patient Reported Allergies a Risk Factor for Poor Outcomes in Total Hip and Knee Arthroplasty?; 6.) Revising an HTO or UKA to TKA: Is it more like a Primary TKA or a Revision TKA?; 7.) At 5 Years Highly-Porous-Metal Tibial Components Were Durable and Reliable: A Randomised Clinical Trial of 389 Patients; 8.) Current Data Does Not Support Routine Use of Patient-Specific Instrumentation in Total Knee Arthroplasty; 9.) Barbed vs. Standard Sutures for Closure in Total Knee Arthroplasty: A Multicenter Prospective Randomised Trial; 10.) Particles from Vitamin-E-diffused HXL UHMWPE Induce Less Osteolysis Compared to Virgin HXL UHMWPE in a Murine Calvarial Bone Model; 11.) Construct Rigidity: Keystone for Reconstructing Pelvic Discontinuity; 12.) Do You Have to Remove a Corroded Femoral Stem?; 13.) Direct Anterior Versus Mini-Posterior Total Hip Arthroplasty with the Same Advanced Pain Management and Rapid Rehabilitation Protocol: Some Surprises in Early Outcome; 14.) Adverse Clinical Outcomes in a Primary Modular Neck/Stem System.

The following checklist is derived from the “Proceedings of the International Consensus Meeting on Periprosthetic Joint Infection”, under the auspices of the Musculoskeletal Infection Society, August 1, 2013. It is available online at http://www.msis-na.org/wp-content/themes/msis-temp/pdf/ism-periprosthetic-joint-information.pdf.

Pre-Operative: Patient Factors, AODM, Obesity, Smoking, Immunodeficiency, ASA score > 2, Prior open surgery?, MRSA history, EtOH abuse, Malnutrition, Anemia, Recurrent infections

Peri-Operative: Avoid pre-op hospitalisation, Chlorhexidine scrub < 6 h pre-op, Hair removal: depilatory or clipper, Appropriate Antibiotic Prophylaxis, Cephalosporin 30–60 min pre-incision, or Vancomycin 1 hour pre-incision, Alcohol based hand emollient after antiseptic soap hand scrub, Limit OR Traffic and Talking!, Double glove, change gloves q2h, ABC bone cement: revisions, high risk patients (immunocompromised), Dilute Betadine lavage?

Post-Operative: Careful wound closure (Sealed, dry), Sterile, impervious dressing × 24 h, Drain optional, < 48 h, Antibiotic prophylaxis × 24 h, Aggressive drainage hematomas

The infected joint arthroplasty continues to be a very challenging problem. Its management remains expensive, and places an increasing burden on health care systems. It also leads to a long and difficult course for the patient, and frequently a sub optimal functional outcome. The choice of a particular treatment program will be influenced by a number of factors. These include the acuteness or chronicity of the infection; the infecting organism(s), its antibiotic sensitivity profile and its ability to manufacture glycocalyx; the health of the patient; the fixation of the prosthesis; the available bone stock; and the particular philosophy and training of the surgeon.

For most patients, antibiotics alone are not an acceptable method of treatment, and surgery is necessary. The standard of care for established infection is two stage revision with antibiotic loaded cement during the interval period and parental antibiotic therapy for six weeks. Single stage revision may have economic and functional advantages however. We have devised a protocol that dictates the type of revision to be undertaken based on host, organism and local factors.

Our protocol has included single stage revision using antibiotic loaded cement in both THA and TKA. This was only undertaken when sensitive organisms were identified preoperatively by aspiration and appropriate antibiotics were available to use in cement. Patients with immunocompromise, multiple infecting organisms or recurrent infection were excluded. Patients with extensive bone loss that required allograft reconstruction or where a cementless femoral component was necessary were also excluded.

Our algorithm was validated first in the knee and extended to infected TKA in 2004. This protocol has now been applied in over 100 TKA revisions for infection between 2004 and 2009. Our single stage revision rate is now over 25%. We continue to see a lower reinfection rate in these carefully selected patients, with high rates of infection control and satisfaction and better functional and quality of life scores than our two stage revision cases.

Whilst our indications are arbitrary and not based on specific biomarkers, we present excellent results for selective single stage exchange. A minimum three year follow-up suggests that these patients have shorter hospital stays, higher satisfaction rates and better knee scores. An ongoing evaluation is in place. One stage revision arthroplasty for infection offers potential clinical and economic advantages in selected patients.

Infection after TKA remains a common reason for reoperation, and represents a significant burden for the patient and health care system. Having effective treatment strategies, therefore, is important to ensure the highest possible rate of success, and the lowest possible rate of reoperation due to treatment failure. This lecture will focus on the chronically infected TKA, where treatment options include either one stage exchange or two stage exchange. Proponents of one stage exchange cite lower costs, less morbidity, and reasonable success rates when compared to two stage exchange protocols. One must realise that strict selection criteria are generally used by proponents of single stage exchange. Favorable pathogens, healthy hosts, good soft tissues, minimal bone loss, etc. are generally used as indications to consider one stage exchange. Such “ideal” clinical situations, however, are exceedingly rare. The overwhelming majority of infected TKA in my practice involve resistant bacteria, significant bone loss, hosts with medical comorbidity, and often, poor soft tissues. In these situations, two stage exchange remains the gold standard to which all other interventions should be compared. With few exceptions, the published success rates for two stage procedures have been better, albeit slightly, than those published for one stage exchanges. Both static and articulating cement spacers have been used with good results. Further research is needed to better define the most effective treatment protocols, however, until further information is available, two stage exchange, with success rates of 80–90%, remains the most successful intervention for chronically infected TKA.

Infection is one of the most devastating complications following total joint arthroplasty. Treatment is difficult, often requiring multiple surgical procedures, prolonged hospitalisation, and long-term intravenous (IV) antibiotic therapy. Failure rates are high for resistant organisms and mixed-flora infections, and antibiotic-loaded cement spacers deliver antibiotics for only a few days and can harbor resistant bacteria on the surface. We have adopted a direct-exchange method with antibiotics infused directly into the joint using Hickman catheters to achieve extremely high levels of intraarticular (IA) antibiotics for six weeks. Hickman catheters have a fibrous cuff that allows soft-tissue ingrowth and seals the surface of the tube to prevent contamination of the joint by tracking along the catheter. Two catheters are inserted to ensure that at least one will be functional for six weeks.

The safety and efficacy of this protocol was evaluated in patients undergoing primary or revision TKA by measuring joint and serum levels of vancomycin following IV administration (as a prophylactic) and IA administration (as a treatment for infected TKA), and comparing the levels with each method. Therapeutic levels of vancomycin were present in the knee following IV or IA administration, but much higher levels were possible with IA administration (avg. of 6.8 and 9,242 µg/mL). Vancomycin achieved therapeutic levels in the synovial fluid of the knee with IV administration, but clearance from the knee was rapid, suggesting that the synovial fluid concentration may be sub-therapeutic for hours before the next IV dose is given. In contrast, IA delivery of vancomycin resulted in peak levels that were many orders of magnitude higher, and trough levels remained therapeutic for 24 hours in both the joint space and in the serum (minimum trough levels of 8.4 and 4.2 µg/mL, respectively). The elimination constant (half-life) of IA-administered vancomycin was 3.1 hours.

This protocol was used in 18 knees (18 patients) with methicillin-resistant Staphylococcus aureus treated between January 2001 and January 2007 with one-stage revision that included debridement, uncemented revision of total knee components, and IA infusion of 500 mg vancomycin via Hickman catheter once or twice daily for 6 weeks. No IV antibiotics were used after the first 24 hours. Serum vancomycin levels were monitored to maintain levels between 3 and 10 µg/mL. Mean serum vancomycin peak concentration was 6±2 µg/mL and the mean serum vancomycin trough concentration was 3±1 µg/mL at 2 weeks postoperative. Knee synovial fluid peak and trough vancomycin levels were measured in two knees. Synovial fluid peak concentrations were 10,233 µg/mL and 20,167 µg/mL and trough concentrations were 724 µg/mL and 543µg/mL, respectively. Minimum follow-up was 27 months (range, 27–75 months). Mean followup was 62 months, (range, 27–96 months). At 2-year follow-up, mean Knee Society score was 83±9. No radiographic evidence of implant migration has occurred. One knee reinfected with MRSA and was reoperated at 5 months. A necrotic bone segment was found, the knee was debrided and revised, and the antibiotic infusion protocol was readministered. The knee remained free of infection at 42 months postoperatively.

Directly infusing antibiotics into the infected area maintains a high local concentration level while minimising systemic toxicity. This method avoids the use of antibiotic-loaded cement and the potential for growth of antibiotic-resistant strains of bacteria. These findings support single-stage revision in cases treated with cementless revision and IA antibiotics.

Wound complications are much more common following knee arthroplasty compared to hip arthroplasty. This is because of the precarious blood supply which contributes to the infection rate which is about twice as high. Many, if not most, infections are related to wound problems. Avoiding wound problems is a critical issue in joint replacement, more so in the knee than the hip. The volume of these procedures is growing rapidly. Infection continues to be a major complication. The incidence is not decreasing and infections are becoming more difficult to treat, because of resistant organisms. Also, the increasing number of procedures in patients with obesity and other risk factors makes wound management a major issue in knee replacement. Many wound problems are avoidable and can be minimised by care to detail by the surgeon.

Salvaging the problem wound is a major issue in total knee replacement currently in order to minimise infection, which remains a major issue and is frequently related to wound healing problems. The first step is identifying the patient at risk and either deferring surgery or optimising the patient to minimise the risk of wound healing problems and subsequent infection. Secondly, is appropriate soft tissue handling with careful attention to choosing the optimal skin incision. Third is taking steps to facilitate primary wound healing and absolutely minimising the risk of persistent drainage, particularly through the very judicious use of anticoagulants. Finally, the delayed wound healing and persistent drainage must be identified early and treated aggressively in order to minimise the risk of infection.

It is clear in 2013 that there is a substantial opportunity to improve patient outcomes after total knee replacement. Much attention in the last decade has focused on the apparent satisfaction gap between patients who have had total hip arthroplasty and those who have had total knee arthroplasty. Most authors note that a higher proportion of total hip patients claim to have complete satisfaction or note that they have forgotten that they had the joint replaced. The concept of “the forgotten joint replacement” is an interesting one because as surgeons and researchers we all recognise that neither total hip replacement nor total knee replacement will completely restore the native hip or knee joint's dynamic 3-D biomechanics or kinematics. What the concept of the forgotten joint does tell us however is that there is a level of kinematic function above which humans cannot detect a difference with normal function. The inherent simplicity of the ball-and-socket design of the hip joint means we can achieve this level of function more reliably and reproducibly than we do in the knee joint. The knee joint presents a more difficult challenge.

Recent data suggests that there is a definable trade-off in total knee prosthesis design, and likely with component position and limb alignment, between those optimised for the best kinematics and those optimised for the best durability using contemporary biomaterials (namely metal, ceramic and ultra-high molecular weight polyethylene). Given this inherent trade-off then there will be an almost never-ending debate about what constitutes “the best” overall knee implant design because that will inevitably require an individual value-judgement about the relative merit of better kinematics or better durability. Currently, we have some insights into this trade-off when we consider the role of unicompartmental knee replacement in 2013. There is little debate that unicompartmental knee replacement results in closer-to-normal knee kinematics than does total knee replacement and that many patients seem to benefit from a quicker recovery and easier rehabilitation. Data from multiple national joint registries however shows that UKR is not quite as durable as total knee replacement (mean yearly failure rate 1.53% for UKR versus 1.26% for TKR). Different surgeons and different surgeons will look at that data however and come to markedly different conclusions about how to act — some will discount the difference in durability and favor the better function/quicker recovery of UKR while other equally intelligent persons will discount the difference in function and prefer the demonstrated better durability of TKR. Like any value-judgement there is no right answer or wrong answer.

As surgeons and researchers we do have opportunities in regard to surgical technique that remain unexplored. We have been limited over the past several decades by thinking primarily in terms of 2-D static analyses of alignment, rotation and ligament balance. This is primarily because most assessments have been done using plain radiographs. The last decade however has seen a marked improvement in out capabilities for 3-D imaging and dynamic assessment of knee joint function. The promise of computer-navigated and robotic-assisted surgery has largely remained unfulfilled as the limitations of 2-D targets have come into focus. It is my belief that tomorrow's gains in total knee replacement will not involve dramatic changes in prosthesis design but instead on defining and then hitting more precise 3-D targets for alignment, rotation and ligament balance in surgery. For surgeons and researchers this is an exciting time as there is a distinct opportunity to improve outcomes for millions of total knee replacement patients over the coming decades.

The cornerstone to proper ligament balancing in TKR is correct varus and valgus alignment in flexion and extension. For alignment in the extended position, fixed anatomic landmarks such as the intramedullary canal of the femur and long axis of the tibia are accepted. When the joint surface is resected at an angle of 5 degrees to 7 degrees valgus to the medullary canal of the femur and perpendicular to the long axis of the tibia, the joint surfaces are perpendicular to the mechanical axis of the lower extremity, and roughly parallel to the epicondylar axis. In the flexed position, anatomic landmarks are equally important for varus-valgus alignment. Incorrect varus-valgus alignment in flexion not only malaligns the long axes of the femur and tibia, but also incorrectly positions the patellar groove both in flexion and extension.

Finding suitable landmarks for varus-valgus alignment has led to efforts to use the posterior femoral condyles, epicondylar axis, and anteroposterior (AP) axis of the femur. The posterior femoral condyles provide excellent rotational alignment landmarks if the femoral joint surface has not been worn or otherwise distorted by developmental abnormalities or the arthritic process. However, as with the distal surfaces, the posterior femoral condylar surfaces sometimes are damaged or hypoplastic (more commonly in the valgus than in the varus knee) and cannot serve as reliable anatomic guides for alignment. The epicondylar axis is anatomically inconsistent and in all cases other than revision total knee arthroplasty with severe bone loss, is unreliable for varus-valgus alignment in flexion just as it is in extension. The AP axis, defined by the lateral border of the posterior cruciate ligament posteriorly and the deepest part of the patellar groove anteriorly, is highly consistent, and always lies within the median sagittal plane that bisects the lower extremity, passing through the hip, knee, and ankle. When the articular surfaces are resected perpendicular to the AP axis, they are perpendicular to the AP plane, and the extremity can function normally in this plane throughout the arc of flexion.

Patient-specific instruments for total knee arthroplasty shift the bone landmark registration and implant positioning of computer navigation from intraoperative to the pre-operative setting. A preoperative MRI or CT scan is mandatory, with the specifications determined by the instrument manufacturer. Default implant sizing and alignment targets must be templated by the surgeon and mapped onto the virtual knee. The surgeon must also review and modify the preoperative computer plan to incorporate any clinical findings, such as flexion contracture or fixed deformity. The finalised preoperative plan is sent back to the implant vendor for fabrication of patient-specific cutting blocks in 4–6 weeks. The supposed advantages of these instruments include more accurate coronal alignment, fewer outliers, no instrumentation of intramedullary canal, decreased operative time, and decreased hospital costs to clean-sterilise instruments. There are many disadvantages of patient-specific instruments, including: cost, preoperative scheduling of imaging, the learning curve for the surgeon, and the uncalculated preoperative planning time. A set of conventional instruments should be available if the custom instruments do not fit properly. One study of 66 knees using PSI reported that frequent surgeon-directed changes were required, 2.4 per knee, implant sizes were changed in 77% of femurs and 53% of tibias, and tourniquet time was not improved. A Markov model study reported an increased cost of $4600 for 4.6 QALYs for patient-specific instruments and that the rate of revision must be reduced by 50% or more for these instruments to be cost-effective. There is little evidence to support the claims made by the manufacturers of these instruments. We advise against the widespread use of these instruments for total knee arthroplasty.

Component and limb alignment are important considerations during Total Knee Arthroplasty (TKA). Three-dimensional positioning of TKA implants has an effect on implant loosening, polyethylene stresses, and gait. Furthermore, alignment, in conjunction with other implant and patient variables such as body mass index (BMI) influence osseous loading and failure rates. Fortunately, implant survivorship after TKA has been reported to be greater than 95% at 20 years, despite up to 28% of TKAs having component position greater than 3 degrees from neutral. How good are we at positioning TKA implants with standard instrumentation? Ritter, et al examined 6,070 primary TKAs and found that from 2 degrees – 7 degrees of valgus, the failure rate was 0.5% for limb alignment. Importantly 28% of the TKAs were outside the 2 degrees – 7 degrees range in the hands of experienced surgeons. What about cases with retained hardware or deformities that preclude IM or EM guides.

Clearly there is room for improvement in surgical technique, but this improvement must be (1) time efficient and cost effective; (2) have a low complication rate, and (3) be reproducible with a minimal learning curve. One of the technologies that has been developed to help surgeons implant and position TKA components is a patient matched guide. Preoperative computerised planning of the arthroplasty, development of patient specific guides, combined with limited mechanical instruments has been a significant step forward for the surgeon and patient.

“The logistical benefits include possible decreased operating room time, decreased turnover time, less time spent sterilising and preparing trays, less inventory, less strain on surgical technicians and nurses, and no capital cost associated with computer navigation. Patient benefits include potentially less tourniquet time, less surgical exposure, no requirement of intramedullary canal preparation, and improved mechanical alignment, which may translate to increased implant longevity. Surgeon benefits include potentially more accurate landmark registration than computer navigation, more efficient surgery, decreased intraoperative stress due to less required decision making, and the ability to perform more surgeries due to time saved.”

Ng, et al compared 569 TKAs performed with patient-specific positioning guides and 155 with manual instruments. The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6 degrees) was similar to manual instrumentation (181.1 degrees), but there were fewer ± 3 degrees hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%).

Total knee replacement is one of the most successful procedures in orthopaedic surgery. Although originally limited to more elderly and less active individuals, the inclusion criteria for TKA have changed, with ever younger, more active and heavier patients receiving TKA. Initially, tibial components were cemented all polyethylene monoblock constructs. Subsequent long-term follow-up studies of these implants have demonstrated excellent durability in survivorship studies out to twenty years. Aseptic loosening of the tibial component was one of the main causes of failure in these implants. Polyethylene wear with osteolysis around well fixed implants was rarely (if ever) observed. Cemented metal-backed nonmodular tibial components were subsequently introduced to allow for improved tibial load distribution and to protect osteoporotic bone. Long-term studies have established that many one-piece nonmodular tibial components have maintained excellent durability.

Eventually, modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80s mainly to facilitate screw fixation for cementless implants. These designs also provided intraoperative versatility by allowing interchange of various polyethylene thicknesses, and to also aided the addition of stems and wedges. Other advantages included the reduction of inventory, and the potential for isolated tibial polyethylene exchanges as a simpler revision procedure. However several studies have documented the high failure rate of isolated polyethylene exchange procedures, probably because technical problems related to the original components are left uncorrected. Since the late 1980's, the phenomena of polyethylene wear and osteolysis has been observed much more frequently when compared with earlier eras. The reasons for this increased prevalence of synovitis, progressive osteolysis, and severe polyethylene wear remain unclear, but there is no question that it was associated with the widespread use of both cementless and cemented modular tibial designs.

Mayo Data: Modular versus All Polyethylene Tibial Components in Primary TKA. The study population included 10,601 adult (>18 years) patients with 14,524 primary TKA procedures performed at our institution between 1/1/1988 and 12/31/2005. Mean age was 68.7 years and 55% were female. Overall revision rates and revisions for loosening, wear/osteolysis were compared across different designs using Cox proportional hazards regression models adjusting for age, sex, calendar year and body mass index (BMI). Over an average 9 years follow-up, a total of 865 revisions, including 252 tibia revisions were performed, corresponding to overall survival of 89% (Confidence intervals (CI): 88%, 90%) at 15 years. In comparison to metal modular designs, risk of tibial revision was significantly lower with all-poly tibias (HR 0.3, 95% CI: 0.2, 0.5). Overall, posterior cruciate-retaining (CR) designs performed better than the posterior-stabilised (PS) designs (p=0.002). With any revision as the endpoint, there were no significant differences across the 18 designs examined. Similarly, there were no significant differences across the 18 designs when we considered revisions for aseptic loosening, wear, osteolysis. Among patient characteristics, male gender, younger age, higher BMI were all significantly associated with higher risk of revisions (p<0.008).

Available data support the use of nonmodular tibial designs in TKA in order to prevent or reduce the chance of backside wear, third body particles from resulting metallic debris and associated polyethylene induced osteolysis. In most patients, but particularly in older patients use of an all polyethylene tibial component is not only more cost effective, but is associated with the best survivorship and lowest risk of revision.

There is no question that excellent long-term results have been demonstrated with all-polyethylene tibial components. Moreover, improvements in polyethylene to increase wear resistance, maintain mechanical strength, and improve oxidative resistance lend even greater credence to the use of an all-polyethylene tibial component. There are several issues of concern. In revision knee replacement for reasons such as patellofemoral problems where the components are otherwise ideal, the arthrotomy performed during the revision usually creates a slight laxity requiring a thicker polyethylene or even a different tibial conformity. With an all-polyethylene tibia, this would require full component revision. It is also true that, even after careful trial reduction, the surgeon occasionally will find that the final construct is slightly lax requiring a thicker final insert. This again is difficult in the situation of all-polyethylene tibia. One of the advantages of an all-polyethylene tibia is to avoid back-side wear that posed a substantial problem in the past. Most component systems have successfully dealt with the problem of back-side wear making the advantage of a nonmodular all-polyethylene tibia moot. Finally, in a modular system, the surgeon has the advantage of cementing all components with the tibial trial and then having the ability to remove the trial component, clear the back of the knee and insert the final insert.

Traditionally, arthritis is a disease which generally affects the elderly population. However, the incidence in young patients is well described and is increasing with the ever-growing obese population. Currently, the non-surgical treatment of osteoarthritis consists of corticosteroid injections, hyaluronic acid injections, weight loss, physical therapy, bracing, orthotics, narcotics, and non-steroidal anti-inflammatory drugs (NSAIDS).

Oral medications (NSAIDS, tramadol, and opioids) can provide effective pain relief. Improvement with NSAIDs has been reported to be 20% relative to baseline, with better improvements seen with selective cox-2 inhibitors, which also have reduced gastrointestinal and renal toxicity. Additionally, the recent AAOS guidelines strongly recommend using NSAIDs or tramadol for pain relief. Although narcotics are effective analgesics, their use in young arthritic patients can potentially predispose individuals to future opioid dependency, and thus should be used sparingly.

The primary purpose of physical therapy is to improve range of motion, strengthen muscles, and improve proprioception. Currently, the AAOS strongly recommends that patients undergo self-management programs, strengthening, low-impact aerobic exercises, and neuromuscular education. Similarly, they moderately recommended that patients with a BMI ≥ 25 undergo weight loss for symptomatic arthritis. Bracing options consist of the following: off-loader braces and transcutaneous nerve stimulation braces. These work to either off-load pressure in the knee or to scramble small nerve pain sensation, respectively.

Corticosteroid injections are used to minimise pain and reduce inflammation in the joint associated with arthritis. However, their long-term repetitive use in young patients is not recommended, and current AAOS guidelines are inconclusive on their effectiveness. Additionally, the AAOS guidelines strongly recommend against the use of acupuncture, glucosamine/chondroitin, and hyaluronic acid injections.

Arthroscopic intervention for early symptoms of arthrosis of the knee was a well-established procedure until Moseley cited his study showing no difference in outcomes when compared to “sham” surgery. Now there is no opportunity for reimbursement with arthroscopic debridement unless mechanical internal derangement can be documented. There are, however, several specific lesions of arthrosis which respond well to arthroscopic intervention and are reimbursed by third party payers.

Arthroscopic three compartment microfracture with non-weight bearing and passive motion for eight weeks post- op has significantly relieved symptoms. Second look biopsies have confirmed type II hyaline cartilage and increased joint interval. Proper patient selection is paramount and guidelines will be discussed.

Isolated severe patellofemoral arthrosis with patella subluxation responds to arthroscopic patella lateral facetectomy. Jones has reported significant pain relief up to two years with this excellent option for a difficult patient problem. The technique and results will be presented in detail.

Loss of terminal extension in the arthritic knee can accelerate deterioration and force earlier decision for TKA. Parson's third tubercle is an osteophyte that forms just anterior to the ACL insertion on the tibia and is the frequent cause of extension loss. Arthroscopic resection of the tubercle results in increased extension and diminishes the stress concentration assuring better longevity for the native knee. The diagnostic characteristics, resection techniques and results of the Dallas series will be presented.

The biomechanical rationale for osteotomy and the pathogenesis of degenerative arthrosis accompanying malalignment has been delineated well. Malalignment of the limb results in added stress on damaged articular cartilage and causes further loss of articular cartilage that subsequently exacerbates the limb malalignment. A downward spiral of progressive deformity and additional loss of articular cartilage occurs over time. Osteotomy can be used to realign the limb, reduce stress on the articular cartilage at risk and share the load with the opposite compartment of the knee. In appropriately selected patients osteotomy is a reliable operation to improve pain and function. Over the past two decades osteotomy has been viewed largely as a temporising measure to buy time for patients before they ultimately have a total knee arthroplasty. In this role, osteotomy has largely been accepted as successful. Substantial improvements in pain and function have been documented and seem to hold up well over a 7 to 10 year period after the osteotomy. Medial opening wedge osteotomy has recently gained in popularity in the United States after a long period of use in Europe. Potential advantages of the medial opening wedge technique include the ability to easily adjust the degree of correction intraoperatively, the ability to correct deformities in the sagittal plane as well as the coronal plane, the need to make only one bone cut, and avoiding the tibiofibular joint. The downsides of the opening wedge technique include the need for bone graft to fill the created defect, a potentially higher rate of non-union or delayed union, and a longer period of restricted weight bearing after the procedure.

Partial knee arthroplasty is making a resurgence as many patients and surgeons are realising that there are good options for preserving normally functioning knee tissues when facing end-stage knee OA without having to automatically proceed to TKA. What are potential advantages of this type of reasoning and could “less be more”? Limited comparative data exists comparing the functional results of partial and total knee replacement surgery. This study will report on patient satisfaction and residual symptoms following TKR, fixed bearing PKR, and mobile bearing PKR. What do the patients say when we aren't around?

TKA is not a benign treatment for isolated unicompartmental knee disease. A multicenter study examining 2,919 TKA's and UKA's found lower rates of overall complications at 11% for TKA's and 4.3% for UKA's. Significant variables for TKA included longer length of stay, more patients sent to an ECF, higher manipulation rate, higher readmission, ICU admission, and transfusion rates. Bolognesi, et al examining 68,790 TKA and UKA, reproduced these results with lower DVT/PE, deep infection rates and lower death rates. The 1 year and 5 year revision rates were higher for UKA's and have been hypothesised to be lower thresholds for revision of dissatisfied UKA vs a TKA with well-fixed implants.

Functional improvements may be better for UKA vs TKA further substantiating the evidence that “less is more” for the surgical treatment of isolated compartmental disease of the knee.

We conducted a multicenter independent survey of 1,263 patients (age 18–75) undergoing primary TKR and PKR for non-inflammatory knee DJD. We examined 13 specific questions regarding pain, satisfaction, and residual symptoms after knee arthroplasty. An independent third party (University of Wisconsin Survey Center) collected data with expertise in collecting healthcare data for state and federal agencies. Multivariate analysis was conducted, significance was set at p<0.05 and adequate power >0.8 was achieved. We controlled for gender, age, income, minority status, and surgical location in the multivariate analysis.

Univariate analysis revealed PKR patients were more likely to be younger, male, and have an income greater than $25,000 than TKR patients. Multivariate analysis showed that mobile bearing PKR patients were 1.81 times more likely to report that their operative knee felt “normal” (p = 0.0109) and 2.69 more likely to report satisfaction with ability to perform activities of daily living than TKR recipients (p = 0.0058). Mobile bearing PKR patients were 44% less likely to report grinding/popping/clicking in the knee (p = 0.0142), 39% less likely to report knee swelling (p = 0.0351), and 40% less likely to report knee stiffness in the last 30 days (p = 0.0167) compared to TKR's. Fixed bearing PKR patients were 51% less likely to experience problems getting in and out of a car compared to TKR patients (p = 0.0129). Fixed bearing PKR's were 60% less likely to be satisfied with the degree of pain relief than TKR (p = 0.0113). The remaining questions revealed a trend for advantages in all categories for the MB-PKR compared to TKR but did not reach statistical significance.

This study demonstrated that patient satisfaction is higher for MB-PKR than TKR with patients more likely reporting the knee to feel normal and that they were more able to perform activities of daily living. Fixed bearing devices were slightly more likely to report less pain relief than TKR. Mobile bearing partial knee replacement had fewer residual symptoms than fixed bearing PKR.

Cemented unicompartmental knee replacement (UKR) has been used for many years and has excellent results in many follow-up studies. However, concerns about the quality of fixation, cementing errors, and radiolucent lines have encouraged the development of cementless prostheses. Mobile bearing UKR are probably the ideal implants for cementless fixation as the loads at the interface tend to be compressive. Prior to the widespread introduction of cementless mobile bearing UKR three studies have been performed to assess this device. In a randomised radiostereometric (RSA) study the migration of cementless and cemented devices were the same in the second year suggesting the quality of fixation achieved was similar. A clinical randomised study demonstrated a dramatic reduction in radiolucent lines with cementless components compared to cemented and no difference in clinical outcome. A prospective cohort study of 1000 patients demonstrated no overall difference in complications or revision rate and identified no contraindications for cementless fixation. There are however anecdotal reports of occasional tibial plateau fracture and early subsidence of cementless components. Data from the National Registers would suggest that the revision rate with cementless is about half that compared to cemented however this difference may be because only experienced surgeons are using the cementless device.

Cementless mobile bearing UKR does seem to be a good evolutionary step in the development of UKR. It is important however that surgeons are trained in the use of the device and are careful with the technique.

Isolated patellofemoral arthritis is not an uncommon problem, with no clear consensus on treatment. Nonoperative and many forms of operative treatments have failed to demonstrate long-term effectiveness in the setting of advanced arthritis. Total knee arthroplasty (TKA) has produced excellent results, but many surgeons are hesitant to perform TKA in younger patients with isolated patellofemoral arthritis. In properly selected patients, patellofemoral arthroplasty (PFA) is an effective procedure with good long-term results. Contemporary PFA prostheses have eliminated many of the patellar maltracking problems associated with older designs, and short-term results, as described here, are encouraging. Long-term outcome and prospective trials comparing TKA to PFA are needed.

While no one would argue the necessary role for the medical management of patients with early knee arthritis, significant controversy remains regarding the ideal treatment for a patient with bone-on-bone osteoarthritis who could equally be treated with a high tibial osteotomy, a unicompartmental total knee, potentially a patello-femoral replacement if dealing with isolated patello-femoral disease or lastly, a complete total knee replacement. While clearly to date there has not been consensus on this issue, a review of the arguments, both pro and con, should be used as a guide to the surgeon in making this clinical judgment.

Many ardent supporters of unicompartmental knee replacements espouse one of the principle benefits of the uni knee as much greater patient satisfaction. Unfortunately, what is never taken into account is the pre-selection bias that occurs in this patient population. Patients with the most minimal amount of arthritis and those with the greatest range of motion are pre-selected to undergo a unicompartmental knee replacement compared to the more advanced arthritic knee with mal-alignment and more significant pre-operative disability that will undergo a total knee replacement. Additionally the sources of data to draw the conclusions must be carefully analysed. We must avoid using data from small series with unblinded patients performed by surgeons expert in the technique. Instead registry data, with its broad based applicability, is a much more logical source of information. Of significance, when over 27,000 patients were assessed regarding satisfaction following knee surgery; there was no difference in proportions of satisfied patients whether they had a total knee or a unicompartmental knee.

Once again large prospective cohort data in the form of arthroplasty registries strongly favors total knee arthroplasty over unicompartmental knee arthroplasty. The Swedish Knee Arthroplasty Registry demonstrated higher revision rates with uni's as compared with total knee replacements. In the Australian Joint Replacement Registry the cumulative 11 year percent revision rate for primary total knee replacements is 6.1% and for unicompartmental knee replacements is 16.3%. The 10 year cumulative percent revision rate for patella femoral replacements 29.9% and lastly bicompartmental replacements are at 10.3% after only 3 years. Higher failure rates in unicompartmental knee replacements seen in Australia has correlated to a significant decrease in the number of uni's being performed, which peaked at 14.6% in 2003 and in 2012 has reduced to 9.0%. There is a direct correlation to age, with younger patients having a significantly higher percentage of revision following unicompartmental knee replacements (25% failure rate at 11 years if less than 55 years old). There is also tremendous variability in the success rate of the uni in the Australian Registry depending on the implant design (5 year cumulative revision rate range 5.0% to 18.9%), which is simply not seen in the total knee replacement population (5 year cumulative revision rate range 1.6% to 7.7%).

While one can perform the philosophical exercise of debating the merits of a total knee versus unicompartmental knee, the evidence is overwhelming that in the hands of the masses a total knee replacement patient will have equal satisfaction to a unicompartmental patient, and will enjoy a much lower probability of revision in the short term and in the long term.

“Expert opinion” is the lowest totem on the academic pole- and yet, “evidence based” medicine does not always provide us answers for the particular, the unusual clinical problem. Well-controlled studies are precisely that: “well controlled”. Life may be randomised, but falls short of being “well controlled”.

The challenge and honor of moderating a panel of experienced and articulate colleagues is to bring out “how they think” and how they formulate a plan for complex cases. The panel members are not only experienced practitioners, but they are the authors of studies that shape our profession. What are the limits to the studies they have published? What insight can they provide us to help understand “level 1” data more astutely? What biases and assumptions support their methods? Nothing achieves that with greater clarity than presentation of complex cases to an accomplished panel.

Several ordinary clinical problems are presented to establish current practice, followed by the unexpected outcomes to illustrate how experts deal with adversity.

The goals of total knee arthroplasty (TKA) are to relieve pain, restore function, and provide a stable joint. In regard to types of implants, the workhorses are posterior cruciate retaining (CR), posterior stabilised (PS), and posterior stabilised constrained (PSC) designs. However, the continuum of constraint now ranges from standard cruciate retaining (CR-S) to CR lipped (CR-L), to anterior stabilised (CR-AS), to posterior stabilised, to a PS “plus” that fits with a PS femoral component but provides a small degree of varus-valgus constraint, to a PSC or constrained condylar type of device, to a rotating hinge. As the degree of deformity, bone loss, contracture, ligamentous instability and osteopenia increases, so does the demand for prosthetic constraint. When deformity is minimal and the posterior cruciate ligament (PCL) is intact and functional, a CR-S device is appropriate. For moderate deformity with deficiency or compromise of the PCL, a CR-AS or posterior stabilised device is warranted. In severe cases, with attenuation or absence of either of the collateral ligaments, a constrained condylar device, with options of stems, wedges and augments, is advisable. In salvage situations, when both collaterals are compromised, a rotating hinge should be utilised. Prerequisites for use of a CR-S device are an intact PCL, balanced medial and lateral collateral ligaments, and equal flexion and extension gaps. With a CR-L bearing, a slight posterior lip is incorporated into the sagittal profile of the component to provide a small amount of extra stability in the articulation. It is important for the surgeon to be aware of the design features of the implant system he or she is using. For example, in a system where the CR-S bearing has 3 degrees of posterior slope and the CR-L bearing has no slope, the thickness of a CR-L bearing posteriorly is approximately 2mm greater than the CR-S. A CR-L bearing is indicated for to provide stability where the flexion gap is just slightly looser than the extension gap and the PCL is intact. If the patient's knee is somewhat lax in flexion and stable in extension, a CR-L bearing may help to stabilise both the flexion and extension gaps yet still allow the knee to obtain full extension, whereas if a CR-S bearing in the next thicker size is used to stabilise the flexion gap, a flexion contracture may result. CR-AS bearings are required less frequently. They are indicated when the flexion and extension gaps are balanced, but the PCL is deficient, and the surgeon does not want to change to a PS design, which requires additional bony resection of intercondylar notch. The PCL is one of the strongest ligaments in the knee, and affords inherent stability to the TKA. In flexion, the PCL not only affords AP stability, but also imparts flexion gap stability, acting as a lateral stabiliser of the medial compartment and a medial stabiliser of the lateral compartment. The PCL has a crucial role with respect to femoral rollback, which imparts added efficiency to the extensor mechanism. PCL retention is a more biologically preserving operative intervention than PS-TKA.

Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long bone morphology, and extra-articular deformity. Correction of varus, valgus, or flexion deformity requires soft tissue releases in conjunction with bone cuts perpendicular to the long axes of the femur and tibia. Cruciate-retaining or -substituting implants can be used based on surgeon preference if the ligaments are well balanced. However, in presence of severe deformity, additional measures may be warranted to achieve alignment and balance. TKA then becomes a more challenging proposition and may require the surgeon to perform extensive releases, adjunct osteotomies and deploy more constrained implants. Merely enhancing constraint in the implant however without attending to releases and extra-articular correction may not suffice.

Preoperative planning, i.e., whether intra-articular correction alone will suffice or extra-articular correction is required, will be highlighted. Surgical principles and methods of performing large releases, reduction osteotomy, lateral epicondylar sliding osteotomy, sliding medial condylar osteotomy, and closed wedge diaphyseal/metaphyseal osteotomy concomitantly with TKA will be illustrated with examples. Results of a large series of TKA with extra-articular deformity resulting from coronal bowing of femoral or tibial diaphysis, malunited fractures, prior osteotomies, and stress fractures will be presented. The techniques reported can successfully restore alignment, pain free motion, and stability without necessarily using more constrained implants.

Functional restoration of patella kinematics is an essential component of TKA, whether the patella is replaced or not. This goal is accomplished by a multifactorial approach: establish proper component position and alignment, especially rotation, avoid IR of the femoral and ER of the tibial components, maintain correct joint line position, and achieve symmetrical soft tissue balance

Most modern TKA designs have an anatomic trochlear groove shape to enable midline tracking. Patella implants are better designed as well with three equilateral lugs for fixation and either dome or anatomic shape. The apex of the patella component should be aligned with the apex of the patella raphe which is more medial than lateral. This method leaves an island of exposed lateral patella facet which is managed with the “lateral slat technique” to be described. It is essentially an intraosseous lateral release. The early mobilisation of modern TKA patients demands watertight closure to prevent soft tissue attenuation and late tracking issues.

When confronted with a patient with a laterally dislocated patella, implementation of the “lateral slat technique” should be done at the approach to obtain midline tracking. Such patients require a median parapatellar (MPP) approach and may need distal-lateral vastus medialis advancement (Insall Procedure).

Adherence to the principles iterated herein will produce a happy patient with good patello-femoral kinematics and function.

Despite improvements in surgical technique, blood loss continues to be an issue following TJR in 2013. Peri-operative blood loss averages between 1000 and 1500 cc during THR and TKR. Multiple methods have been employed in attempts to minimise this loss. Concepts such as hypotensive anesthesia, tourniquet use, intraoperative blood salvage and autologous pre-donation and postoperative re-infusion drains as well as the use of bipolar sealants, fibrin sprays and thrombin agents have been tried with varying degrees of success.

Recently there has been a surge of interest in the use of antifibrinolytics such as Tranexamic Acid (TXA), Aprotinin and Aminocaproic Acid. These medications have a long history of use in other fields such as cardiac and oral surgery but are just recently being utilised following TJR. Of these medications, TXA has been by far the best studied.

TXA is a synthetic amino acid that inhibits fibrinolysis by competitively and reversibly blocking the Lysine binding sites on plasminogen. This inhibits its activation and slows the conversion from plasminogen to plasmin and this prohibits the binding of plasmin to fibrin and the subsequent dissolving of clot formation.

TXA can be used either topically or intravenously and there are more than 50 clinical papers that have evaluated the effectiveness of TXA in TJR. There is abundant scientific data to support its safety with minimal increased risk of thrombosis and its use should be considered as a safe, effective and economical means of reducing blood loss in TJR in 2013.

Flexion contractures are a common finding in an end-stage arthritic knee, occurring in up to 60% of patients undergoing total knee arthroplasty. Fixed flexion deformities may result from posterior capsular scarring, osteophyte formation, and bony impingement. It is essential to correct this deformity at the time of total knee arthroplasty, as a residual flexion contracture will result in joint overload and abnormal gait mechanics. This may translate to a slower walking velocity, shorter stride length, and pain.

This presentation will discuss a systematic way of dealing with flexion contractures to ensure that the total knee arthroplasty will achieve full extension. The surgical technique for treating fixed flexion deformity about the knee includes release of the posterior cruciate ligament, posterior capsular release, adequate distal femoral bone resection, and removal of osteophytes.

Postoperatively, attention must be divided between obtaining maximal flexion and full extension. Should a flexion contracture be noted upon the postoperative visit, additional measures should be taken to address it.

To consider bilateral simultaneous knee replacement, both knees must have significant structural damage. It is best if the patient can't decide which knee is more bothersome. In borderline cases, ask the patient to pretend that the worse knee is normal and if so, would they be seeing you for consideration of knee replacement on the less involved side. If the answer to this question is “yes,” consider the patient a potential candidate for bilateral knee replacement. If the answer is “no,” recommend operating only on the worse knee, and expect that the operation on the second knee can probably be delayed for a considerable period of time.

Strong indications for bilateral simultaneous TKA are bilateral severe angular deformity, bilateral severe flexion contracture, and anesthesia difficulties, i.e., patients who are anatomically or medically difficult to anesthetise, such as some adult or juvenile rheumatoid arthritis patients or patients with severe ankylosing spondylitis.

Relative indications for bilateral simultaneous TKA include the need for multiple additional surgical procedures to achieve satisfactory function and financial or social considerations for the patient. Contraindications to bilateral TKA include medical infirmity (especially cardiac), a reluctant patient, and a patient with a very low pain threshold.

When performing bilateral simultaneous TKA, both limbs are prepped and draped at the same time. An initial dose of an intravenous antibiotic is given (usually 1 gram of a cephalosporin) before inflation of the tourniquet. Surgery begins on the more symptomatic side or on either side if neither knee is significantly worse than the other. The reason for starting on the more symptomatic side is in case surgery has to be discontinued after only one procedure owing to anesthetic considerations.

After the components have been implanted on the first side, the tourniquet is deflated and a second dose of intravenous antibiotic is administered (usually 500 mg of a cephalosporin). After the joint capsule is closed and flexion against gravity is measured, one team completes the subcutaneous and skin closure on the first side while the other team inflates the second tourniquet and begins the exposure of the second side. When the second tourniquet is deflated, a third dose of antibiotic is given (usually 500 mg of a cephalosporin for a total dose of 2 g for both knees).

Because of concern about the potential for cross-contamination of the knee wounds when instruments used during the final stages of skin closure on the first knee are maintained on the field and used on the second knee, they should probably be handed off the field and outer surgical gloves changed.

Most patients will report after their complete recovery that they are glad they did both knees at the same time. A patient who has any uncertainty about proceeding with bilateral surgery should have only one knee done at a time. In many cases, the second side receives a “reprieve,” becoming more tolerable after the first side has been operated on.

Much is made of the role of good judgment in the reduction of error, although it is undeniable that error has a role in the development of such judgment. Hence retrospectives from those with experience have merit if we can assume they have introspection and insight as well.

In this panel discussion we will explore the experience of a group of renowned surgeons in the field of hip and knee reconstruction, and we will seek their wisdom on new techniques and technology, honed over a few decades of exciting discovery and oft-times unexpected disappointment.

In addition, as the session title suggests, these revered colleagues will be invited to reflect on those they encountered, in person or otherwise, by happenstance or design, who profoundly influenced their careers and how that influence shaped their lives and the lives of those entrusted to their care.

“If I have seen further than others, it is by standing upon the shoulders of giants” Sir Isaac Newton.

Previous studies examined failure mechanisms for revision TKA performed between 1986 and 2000. These studies demonstrated that a majority of failures occurred in the first few years, with a disproportionate amount for infection and implant-associated failure mechanisms. Since these studies were published, efforts have been made to improve implant performance and instruct surgeons towards best practice total knee arthroplasty techniques. Recently our center participated in a multi-center evaluation of revision TKA cases during 2010 and 2011. The purpose was to report a detailed analysis of the failure mechanism and the time to failure to determine whether the failure mechanism of primary TKA has changed over the past 10–15 years. Further, we evaluated the effect of failure mechanism on extent of revision and whether revision surgery was performed at the same location as the index procedure. We identified 844 revisions of failed primary TKA. Aseptic loosening was the predominant mechanism of failure (31.2%), followed by instability (18.7%), infection (16.2%), polyethylene wear (10.0%), arthrofibrosis (6.9%), and malalignment (6.6%). Mean time to failure was 5.9 years (range 10 days to 31 years). 35.3% of all revisions occurred less than 2 years after the index arthroplasty, with 60.2% in the first 5 years. In contrast to previous reports, polyethylene wear is not a leading failure mechanism and rarely presents before 15 years. Implant performance is not a predominant factor of knee failure. Early failure mechanisms are primarily surgeon-dependent.

TKA is among the fastest growing interventions in medicine, with procedure incidence increasing the most in younger patients. Global knee scores have a ceiling effect and do not capture the presence of difficulty or dissatisfaction with specific activities important to patients.

We quantified the degree of residual symptoms and specific functional deficits in young patients who had undergone TKA.

In a national multicenter study, we quantified the degree of residual symptoms and specific functional deficits in 661 young patients (mean age, 54 years; range, 19–60 years; 61% female) at 1 to 4 years after primary TKA.

To eliminate observer bias, satisfaction and function data were collected by an independent, third-party survey center with expertise in administering medical outcomes questionnaires.

Overall, 89% of patients were satisfied with their ability to perform normal daily living activities, and 91% were satisfied with their pain relief. After TKA, 66% of patients indicated their knees felt normal, 33% reported some degree of pain, 41% reported stiffness, 33% reported grinding/other noises, 33% reported swelling/tightness, 38% reported difficulty getting in and out of a car, 31% reported difficulty getting in and out of a chair, and 54% reported difficulty with stairs. After recovery, 47% reported complete absence of a limp and 50% had participated in their most preferred sport or recreational activity in the past 30 days.

When interviewed by an independent third party, about 1/3 of young patients reported residual symptoms and limitations after modern TKA. We recommend informing patients considering surgery about the high likelihood of residual symptoms and limitations after contemporary TKA, even when performed by experienced surgeons in high-volume centers, and taking specific steps to set patients’ expectations to a level that is likely to be met by the procedure as it now is performed.

The causes of pain after TKA can be local (intra or extra-articular) or referred from a remote source. Local intra-articular causes include prosthetic loosening, infection, aseptic synovitis (wear debris, hemarthrosis, instability, allergy), impingement (bone soft tissue or prosthetic), an un-resurfaced patella and stress fracture of bone or the prosthesis. Some surgeons think that isolated component mal-rotation can be a source of pain, but component mal-rotation is rarely present in the absence of other technical abnormalities.

Local extra-articular causes include pes anserine bursitis, saphenous neuroma/dysasthesias, post-tourniquet dysasthesias, complex regional pain syndrome and vascular claudication.

Referred pain is most often from an arthritic hip or radicular pain from a spinal source. Patients with fibromyalgia can have persistent pain following their knee arthroplasty and should be warned of this possibility.

Evaluation of the patient includes a history, physical exam, joint aspiration and plain radiographs. In selected patients, an anesthetic joint injection, bone scan, CT scan or MRI with metal subtraction may be helpful in the diagnosis. The joint aspiration should include a CBC and differential as well as an aerobic and anaerobic culture. Fungal and TB cultures are sometimes indicated.

Re-operation for pain of unknown etiology following TKA is unlikely to yield an excellent result and both surgeons and patients should be aware of this probability.

Stiffness after a TKA might be said to be present when reasonable functions of daily living cannot be performed or can only be performed with difficulty or pain. This will certainly be true if flexion is less than 75 degrees and/or there is a 15-degree lack of full extension. The purpose of this presentation is to discuss the causes of a stiff TKA, consider the aspects of surgical technique that are associated with the occurrence of stiffness, present post-surgical management that impacts on the development of stiffness and summarise the results of the surgical treatment of a stiff TKA.

Pre-operative stiffness is strongly correlated with post-operative limitation of motion. Therefore, pre-surgical measures to optimise motion should be carried out. These include appropriate physical therapy, adequate pain management and a discussion with the patient of the issues likely to affect post-operative range of motion. It is particularly important to discuss with the patient appropriate expectations with regard to the likely range of motion that will be achieved following TKA surgery.

There are a number of steps that can be taken during the performance of a TKA that have an impact on range of motion. Osteophytes must be removed. Correctly sized implants must be used to avoid over-stuffing the tibio-femoral and patello-femoral compartments. Mal-positioning implants and the extremity can adversely affect range of motion. Inadequate bone resection will also lead to a reduced range of motion. Improper soft tissue balancing in both flexion and extension may be associated with post-surgical stiffness.

Post-operative management must include adequate pain management as well as appropriate rehabilitation. Close post-surgical surveillance will help identify those patients likely to achieve unsatisfactory range of motion. Manipulation of appropriate patients within the first 6 weeks following surgery is usually associated with a satisfactory final range of motion.

When persistent stiffness occurs, an attempt must be made to identifying possible causes, including component mal-alignment or mal-rotation, component mis-sizing or mis-positioning and inadequate soft tissue balancing. The surgical treatment of a stiff total knee include: 1) arthroscopic debridement and manipulation; 2) arthrotomy with debridement; and 3) single or complete component revision. Although surgical intervention often results in improved range of motion, the results are variable and somewhat limited.

A key component to the success of total knee replacement is the health and integrity of the extensor mechanism. While there are issues related to the patella, such as fracture, dislocation, subluxation, clunk due to peripatellar fibrosis and anterior knee pain, the overall integrity of the extensor mechanism is of tantamount importance in providing an excellent functional outcome. During total knee replacement it is of utmost importance to preserve the anatomic insertion of the patellar tendon on the tibial tubercle. However, after total knee replacement, a fall or extreme osteoporosis of the patella may cause a rupture of the patellar tendon, distally or proximally, and possibly the quadriceps tendon off of the proximal pole of the patella.

Simple repairs of the patellar tendon avulsion may involve use of the semitendonosis and gracilis tendons along with primary repair of the tendon. Usually, patella infera develops after such a repair affecting overall strength and function. For severe disruptions of the extensor mechanism that are accompanied by a significant extensor lag, autologous tissue repair may not be possible. Thus, there are three techniques for reconstruction of this difficult problem: Extensor mechanism allograft with bone-patellar tendon-patella-quadriceps tendon, extensor mechanism allograft with os calcis-Achilles tendon construct and Marlex-mesh reconstruction for patellar tendon avulsion.

The key to success of extensor mechanism allograft is proper tensioning of the allograft at full extensor and immobilisation for 6 weeks. Rosenberg's early experience showed that the allograft works best placed at maximum tension in extension. Rubash has described the use of the os calcis-Achilles tendon which does not utilise a patellar substitute. Hansen has recently described excellent results with the use of Marlex mesh to act as a structural reinforcement to the patellar tendon when it is avulsed.

Polyethylene damage, including normal wear, may occur for a variety of reasons. The opposing view would have one believe that all of those reasons are malignant and lead to unavoidable, reasonably short term failure.

The logical question is first whether simple spacer change has any clinical advantage, e.g. being a smaller operation, easier to rehab, recoup from, and sparing the unavoidable bone loss associated with the removal of ostensibly firmly fixed components. It is clear that all of these 3 or 4 points are true. That is, spacer change is a small procedure, characterised by all the points mentioned.

The only relevant questions are whether main component removal is necessary all the time because there is a more basic problem that portends rapid failure or because failure to take advantage of one-staging to a more extensive revision early, makes that more extensive revision impractical or more difficult for the patient when delayed any given number of years.

The answers to these last two considerations or questions are clearly no.

A bad batch of poly can lead to osteolysis or wear independent of malalignment or ligament imbalance. It should be treated by poly change and where appropriate bone grafting.

Poly wear in the presence of malalignment of some degree can be more controversial. Factors to consider should be (i) the availability of presumably improved poly from the given manufacturer, (ii) the amount of malalignment, (iii) the age of the patient, and (iv) any prospects for changing the alignment short of main component revision. The latter can be done with asymmetric poly, or for femoral malalignment, correction of that alignment with osteotomy, in selected instances.

The patient age factor relates to both ends of the spectrum. In the younger patient one wants not to waste current main components, i.e. prematurely move to the patient's next prosthesis. And, the very elderly patient may have a clinical situation well suited to the smaller operation and a life expectancy that would exceed the albeit imperfect durability of a residually malaligned spacer change.

So, even if most spacer changes do not last as long as ordinary primary components, that does not mean that none will. Nor does it mean that they will not last long enough in an extremely elderly patient.

Vancouver A: If minimal displacement and prosthesis stable can treat nonoperatively. If displacement is unacceptable and/or osteolysis is present consider surgery.

AL: Rare, avulsions from osteopenia and lysis. If large, displaced and include large portion of calcar-can destabilise stem and prompt femoral revision.

AG: More common. Often secondary to lysis. Does not usually affect implant stability. Minimal displacement. Treat closed × 3 months. Revise later is needed to remove the particle generator, debride defects and bone graft. Displaced with good host bone stock. Consider early ORIF and bone grafting.

Vancouver B:

B1: Rarely non-operative. ORIF with femoral component retention. Need to carefully identify stem fixation. B2's classified as B1's are doomed to fail. B1's correctly identified treated with plate, allograft struts or both. High union rates with component retention.

B2: Femoral revision +/− strut allograft. Best results seen with patients revised with uncemented, extensively porous coated femoral stems. May use modular, fluted taper stems.

B3: Proximal femoral replacement - Tumor prosthesis, Allograft Prosthetic Composite (APC). Uncemented femoral stem - Extensively porous coated, Fluted, tapered stem, Allograft strut.

Vancouver C: Treat with standard fracture techniques. These fractures are away from the femoral prosthesis. Rarely nonoperative. Fixation options – Cerclage, Strut Allograft, Plate fixation, Retrograde IM nail, or a Combination thereof. Avoid stress risers between implants. Bypass (overlap) fixation. Consider allowing 2.5 cortical diameters between devices.

The ultracongruent insert has been used since 1991 beginning with the Natural- Knee, then manufactured by Sulzermedica. It has posterior stabilising with the 12.5mm anterior build up with a significantly more congruent articulation. This translates to higher contact areas and theoretically lower wear. The higher central eminence provides some medial lateral stability. This style insert is now available from at least seven different manufacturers.

The first study was reported in the 2000 Journal of Arthroplasty with Hofmann et al., comparing 100 ultracongruent inserts with 100 PCL sparing inserts with an average five-year follow-up. Knee scores and range of motion were similar or no dislocations or subluxations were noted. We found sparing since there is no box cut and requires less time for surgery. This insert provided excellent stability in all ranges of motion.

Indication for this surgery is deficiency or compromise of the PCL.

Contraindications are attenuation or absence of either one or both collateral ligaments where a more constrained device is suggested.

While a tourniquet is traditionally used to obtain a dry field during primary TKA (and is also thought to reduce perioperative blood loss), adverse effects of tourniquet use have been reported. Avoiding routine use of the tourniquet during TKA can minimise certain complications while improving the quality of the early result.

Most studies of TKA with and without tourniquet show little difference in all forms of blood loss except for intraoperative. Some studies even show less overall blood loss in groups without tourniquet use. Modern techniques to minimise intraoperative loss have included topical treatments, systemic medications, as well as a bipolar tissue sealer. Visualisation of bleeding vessels and their management intra-operatively can substantially reduce early post-op hemarthrosis.

Tourniquet use has also been related to post-operative thigh pain. This is a negative aspect of tourniquet use that can interfere with physical therapy and rehabilitation. Occasionally it can be a significant factor in post-op recovery. Data supports the fact that avoiding a tourniquet or at least reducing pressure to the minimum necessary may help to reduce post-operative thigh pain.

Ischemia and tissue damage can affect neuromuscular function and rehabilitation following TKA. The time necessary to achieve straight leg raising and knee flexion is delayed by tourniquet use during TKA. Compressive nerve injury also may result in secondary effects of denervation on distal tissues. This denervation can delay recovery of blood flow and increase vessel spasm, hemorrhage and edema. The degree of dysfunction is related to the magnitude of tourniquet compression.

Tension in the lateral retinaculum is directly affected by tourniquet use. Observations from these studies would indicate that lateral release should be performed only if found necessary after tourniquet deflation in order to minimise the potential morbidity that accompanies this procedure.

Although thromboembolic events can occur during TKA without, tourniquet use is associated with more frequent events when it is used.

Finally, it is prudent to avoid the use of a tourniquet in patients with vascular calcifications around the knee or abdomen due to advanced arteriosclerosis, previous bypass grafts, or reduced limb or tissue blood supply for any reason. Routine TKA with minimal tourniquet use greatly simplifies its performance in those settings where it is contra-indicated.

There has been ongoing debate for many years on the relative merits of routine tourniquet use while performing a total knee replacement. Interestingly there have been many retrospective reviews and opinion articles on the topic, but little in the way of well powered prospective randomised clinical trials.

Those that dislike the premise of routine tourniquet use usually cite a list of either very rare complications, or theoretical concerns (nerve damage, muscle function, wound healing issues).

Like most debate topics however, the issue is usually a shade of grey, rather than black and white, if the pro/con arguments are evaluated individually.

There can be little debate that intraoperative blood loss is less with the use of a tourniquet. This has been demonstrated in multiple studies and is clearly intuitively obvious. Interestingly the overall blood loss (intraop + postop) may however be the same regardless of tourniquet use. Having a dry operative field however is important in achieving adequate cement fixation, and if tourniquet use is not employed, an alternative should be.

There is an overwhelming body of literature that supports the understanding that increased OR time directly correlates to increased infection rates in total joint arthroplasty. Proponents of not using a tourniquet will often have alternates to achieving a dry operative field that clearly add time to the procedure – meticulous hemostasis, air delivery systems, etc. This increased OR time may come at the cost of increased infection risk.

There is clearly a need for well-designed randomised clinical trials evaluating the practice of routine tourniquet use in TKA. Any trial done however must look critically at factors such as OR time, costs of alternatives, and potential long-term outcome effects.

The use of stems in revision TKA enhances implant stability and thus improves the survival rate. Stemmed components obtain initial mechanical stability when there is deficient metaphyseal bone. However the optimal method of stem fixation remains controversial, which includes selection of stem size, length or the use of cemented vs. cementless stems. Although postulated by many surgeons, there is no sufficient evidence, that cementless or hybrid fixation does perform better in the long term outcome, than cemented stems. In addition a number of studies, even from the U.S., suggested that there might be a benefit for the long term survival for cemented stems in revision TKA.

Obviously cemented stems have some few advantages in revision set up as: topic antibiotic delivery and initial strong fixation. While main disadvantages arise during limited/poor bone quality for initial cancellous bone-cement fixation; revision with removal of a long cement mantle and re-cementing into a previously cemented canal. Furthermore removing a fully cemented implant can be much more time consuming. The Endo Klinik has currently over 30 years of experience utilising cemented stems in combination with a rotating hinge implant in revision TKA, including satisfactory long-term results.

However we are aware of this technique associated limitations, including aseptic loosening and further conversion to a re-revision with necessary impaction bone grafting.

Generally it has to be mentioned, that type of stem and reconstruction type if often driven by surgeons own and institutional preference.

The “keel” is the relatively short part of the undersurface of the tibial component that extends into the medullary canal. Most knee replacement systems have the capacity to attach modular stem extensions for enhanced intra-medullary fixation for revision.

Diaphyseal length, large diameter stems may also guide positioning of trial components and are ideal for accurate surgical technique, even if fully cemented stems are eventually implanted.

Smaller diameter non-modular stem extensions may be used for fully cemented fixation. They do not however guide component position very accurately and do not make sense for uncemented fixation. Revision surgery is different from primary surgery and enhanced fixation with some type of intramedullary fixation is highly appropriate, especially if constrained devices might be required.

Options for enhanced intramedullary fixation are: 1. Fully cemented metaphyseal or shorter stems; 2. Diaphyseal engaging press fit stems; and 3. Very short fully cemented stems with trabecular metal cone fixation.

Metaphyseal length press fit stems do not provide reliable fixation in revision TKA. Revision with primary components or constrained components without any stem extension is not advised.

Revision TKR is a challenging surgical procedure that requires considerable pre-operative evaluation and planning. The diagnostic evaluation for the presence of periprosthetic sepsis has been well described and is of paramount importance. Optimal results of revision TKR mandate that the etiology of failure, and reason for revision, be clearly understood, since the outcome of revision TKR for unexplained pain has been disappointing.

Physical examination should include a careful assessment of range of motion, ligament stability, quality of the soft tissues around the knee and the location of any prior incisions around the knee. The above information provides valuable information about any potential difficulties with surgical exposure, selection of the safest surgical incision, potential problems with soft tissue coverage and selection of an implant with the proper degree of constraint.

Plain radiographs should be carefully evaluated for fixation, alignment, osteolysis and extent of bone deficiency around each component. This information is essential in order to develop a strategy for removal of existing implants and cement, obtaining satisfactory fixation of a new implant and managing bone deficiencies encountered at the time of surgery using a variety of stems, augments and bone grafts.

The goals of revision TKR are simple to state but difficult to obtain: stable implant fixation, a healed surgical wound without infection, restoration of alignment, stability and a functional range of motion. Despite the most conscientious pre-operative planning, one must be prepared for the unexpected and any surgical plan requires a sound “back-up” plan.

Exposure in revision total knee replacement can be quite challenging due to scar formation from one or many previous incisions. Disruption of the patellar or quadriceps tendon during revision must be avoided at all costs and many surgical maneuvers have been described to permit safe exposure in order to remove the implants during the initial stage of reconstruction. Standard maneuvers include recreation of the medial and lateral gutters, patient dissection to allow the soft tissue to stretch over time and proximal medial exposure of the tibia and release of the semimembranosis tendon insertion.

There are three specialised techniques for exposure during revision total knee replacement: the quadriceps snip as described by Insall, the V-Y quadriceps turndown as described by Coonse and Adams, and the tibial tubercle osteotomy as described by Whiteside.

The quadriceps snip is a proximal lateral extension of the medial arthrotomy used during a standard approach. It is easy to perform and can be used for most revision situations. This is should be the standard first choice for gaining exposure in revision surgery. The V-Y quadriceps turndown is quite extensile and is a combination of a lateral retinacular release connected to the proximal portion of the medial arthrotomy. Although it allows excellent exposure in revision situations, it is associated with extensor weakness and extensor lag. The Whiteside tibial tubercle osteotomy is also a versatile approach. Care should be taken to preserve a lateral periosteal sleeve, and subsequent repair with wire presents the best healing possibility. It is quite elegant in providing access to the proximal tibia to facilitate removal of a well fixed, stemmed tibial component.

Converting unicompartmental knee arthroplasty (UKA) to total knee arthroplasty can be difficult, and specialised techniques are needed. Issues include bone loss, joint-line, sizing, and rotation. Determining the complexity of conversion preoperatively helps predict the need for augmentation, grafting, stems, or constraint. We examined insert thickness, augmentation, stem use, and effect of failure mode on complexity of UKA conversion. Fifty cases (1997–2007) were reviewed: 9 implants (18%) were modular fixed-bearing, 4 (8%) were metal-backed nonmodular fixed-bearing, 8 (16%) were resurfacing onlay, 10 (20%) were all-polyethylene step-cut, and 19 (38%) were mobile bearing designs; 5 knees (10%) failed due to infection, 5 (10%) due to wear and/or instability, 10 (20%) for pain or progression of arthritis, 8 (16%) for tibial fracture or severe subsidence, and 22 (44%) due to loosening of either one or both components. Complexity was evaluated using analysis of variance and chi-squared 2-by-k test (80% power; 95% confidence interval). Insert thickness was no different between implants (P=0.23) or failure modes (P=0.27). Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Failure mode was predictive of complexity. Reestablishing the joint-line, ligamentous balance, and durable fixation are critical to assuring a primary outcome.

Instability currently represents the most frequent cause for revision total knee replacement. Instability can be primary from the standpoint of inadequately performed collateral and/or posterior cruciate ligament balancing during primary total knee replacement or it may be secondary to malalignment secondary to loosening which can develop later progressive instability. Revision surgery must take into consideration any component malalignment that may have primarily contributed to instability.

Care should be given to assessing collateral ligament integrity. This can be done during physical examination by radiological stress testing to see if the mediolateral stress of the knee comes to a good endpoint. If there is no sense of a palpable endpoint, then the surgeon must assume structural incompetency of the medial or lateral collateral ligament or both. In posterior cruciate retaining knees, anteroposterior instability must be assessed.

For instability, must revisions will require a posterior cruciate substituting design or a constrained condylar design that are unlinked. However, if the patient displays considerable global instability, a linked, rotating platform constrained total knee replacement design will be required. Recent data has shown that the rotating hinges work quite well in restoring stability to the knee with maintenance of the clinical results over a considerable length of time.

During revision surgery, laminar spreaders may be utilised to assess the flexion and extension spaces after the tibial platform is restored. If a symmetric flexion and extension space are achieved, then the collateral ligaments are intact. Depending on the remaining existing bone stock, a posterior stabilised or constrained condylar unlinked prosthesis may be used for implantation. If there is considerable asymmetry or a large flexion/extension mismatch, then a rotating hinge design should be utilised.

Intramedullary stems should be utilised in most cases when bone integrity is suspect and insufficient. Currently, stems should be placed cementless to permit easier future revision. Cementing the stems is only recommended if there is lack of intramedullary isthmic support. However, revision of fully cemented revision implants may be quite difficult later.

Infection should be ruled out by aspiration off of antibiotics prior to any revision operation, especially if loosening of the components represents the cause of instability. The surgeon should attempt to restore collateral ligament balance whenever possible as this yields the best clinical result.

The amount of bone loss due to implant failure, loosening, or osteolysis can vary greatly and can have a major impact on reconstructive options during revision total knee arthroplasty. Massive bone loss can threaten ligamentous attachments in the vicinity of the knee and may require use of components with additional constraint to compensate for associated ligamentous instability. Classification of bone defects can be helpful in predicting the complexity of the reconstruction required and in facilitating preoperative planning and implant selection. One very helpful classification of bone loss associated with TKA is the Anderson Orthopaedic Research Institute (AORI) Bone Defect Classification System. This system provides the means to compare the location and extent of femoral and tibial bone loss encountered during revision surgery. In general, the higher grade defects (Type IIb or III) on both the femoral and tibial sides are more likely to require stemmed components, and may require the use of either structural graft or large augments to restore support for currently available modular revision components. Custom prostheses were previously utilised for massive defects of this sort, but more recently have been supplanted by revision TKA component systems with or without special metal augments or structural allograft.

Options for bone defect management are as follows: 1) fill with cement, 2) fill with cement supplemented by screws or K-wires, 3) Morsellised bone grafting (for smaller, especially contained cavitary defects), 4) Small segment structural bone graft, 5) Impaction grafting, 6) Large prosthetic augments (cones), 7) Massive structural allograft-prosthetic composites (APC), 8) Custom implants.

It is very helpful for revision surgeons to have a variety of reconstructive options available, even despite a well thought-out preoperative plan. Preoperative planning is important but the plan that results may require alteration during the course of the surgery to accommodate bone defects which are either less or more severe than thought pre-operatively, and to adjust to variable quality and extent of host bone remaining, as this provides the mechanical platform for the reconstruction. Maximising support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis.

Bone defect management during revision total knee arthroplasty can provide a wide range of challenges from relatively trivial problems with small defects manageable with cement or small amounts of cancellous graft to massive deficiencies that may defy reconstruction except with allograft prosthetic components or large segmental replacing tumor-type implants. The more common Type II deficiencies increasingly seen in the context of particulate driven osteolysis demand a wide range of implant and bone graft options so that an individualised reconstruction can be accomplished for that particular patient based on bone defect size, location, quality of bone remaining, ligamentous status, and anticipated patient demands.

Despite our best efforts, occasionally, certain patients will have multiply operated, failed reconstructions after TKA. There are situations where further attempts at arthroplasty are unwise, for example, chronic infections with multiple failed staged reconstructions. A careful preoperative evaluation of the patient is critical to guide decision-making. An assessment of medical comorbidity, functional demands, and expectations is important. Regarding the extremity, the severity of bone loss, soft tissue defects, ligamentous competency, and neurovascular status is important. The next step is to determine whether the knee is infected. The details of such a workup are covered in other lectures, however, the author prefers to aspirate all such knees and obtain C reactive protein and Sedimentation Rates. For equivocal cases, PCR may be helpful. If no infection is present, complex reconstruction is considered. Segmental megaprosthesis and hinged prostheses may be helpful. Often, soft tissue reconstruction with an extensor mechanism allograft or muscle flap is required. Obviously, these are massive undertakings and should be done by experienced surgeons. If a prosthesis is not a good option, other options include definitive resection, knee arthrodesis, or above knee amputation. A careful discussion with the patient about the pros and cons is necessary to allow them to partner with the surgeon in the decision-making. Definitive resections are reserved for minimal to non-ambulators with significant co-morbidity that do not desire an AKA. AKA is often the best option, however, it should be noted that the majority of these patients will never ambulate with a prosthesis due to the energy requirements necessary to do so. High complication rates and reoperation rates have been reported with AKA after TKA. Functional outcome studies have generally shown better function with arthrodesis than with AKA. Arthrodesis can be effective and can be accomplished with several methods. If active infection is present, and external fixator is typically chosen. If no infection is present then plating or long intramedullary nailing is considered. Plating requires healthy anterior soft tissues due the bulk associated with double plating techniques. The highest union rates have been reported with long nails. The author therefore prefers to use long nails after eradicating infection with a staged procedure (interval spacer) rather than to use an external fixator. Union rates are higher with nails, but the risk of re-infection is slightly higher as well. Careful attention to detail is necessary to minimise complications.

The designs available today have greatly improved our ability as surgeons to perform successful total knee revision surgery. However, as more and more knee replacements are in service for longer periods of time, the numbers of revisions have increased and have required us as surgeons to address challenging problems including infection, instability and bone loss from wear, osteolysis and loosening.

Understanding the problems needed to be addressed is paramount. Careful preoperative planning is key. Knowing the cause of failure and the aspects of reconstruction that need to be addressed including skin, soft tissues, extensor mechanisms, bone and ligament loss is critical.

Intraoperatively, understanding and applying principles related to establishing joint lines, balancing flexion extension gaps, addressing bone loss and ligament instability and constructing stable knee replacements with the use of stabilising implant articulations, bone deficiency reconstruction with augments and grafts as well as cones and sleeves, and stems for implant stability is also essential.

Postoperatively, rehabilitation and follow-up must be tailored to the individual patient because of the marked nuances of construct in the various revision scenarios.

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal pain management. This has reduced length of stay and opened the opportunity for cost savings and even outpatient joint replacement surgery for appropriately selected patients. The hallmark of this program is preemptive pain control with oral anti-inflammatory agents, gabapentin, regional anesthetic blocks that preserve quad function for TKA (adductor canal block) and long acting local anesthetics with the addition of injectable ketorolac and acetaminophen. Over the past two years utilising this type of program over 60% of our partial knee replacement patients are now returning home the day of surgery.

We currently utilise a long acting local anesthetic delivery medication consisting of microscopic, spherical, lipid-based particles composed of a honeycomb-like structure of numerous nonconcentric internal aqueous chambers containing encapsulated bupivacaine separated from adjacent chambers by lipid membranes. Bupivacaine is released from the particles with diffusion of the drug over an extended period of time that more closely matches the time course of postsurgical pain following joint replacement surgery. Trials have demonstrated that a single dose administered via deep tissue infiltration is effective at reducing pain up to 72 hours.

There has been a widespread appreciation on the part of both patients and surgeons that pain control following total knee replacement is an important goal. The concepts of both preemptive analgesia and multimodal pain protocols have become increasingly popular. In addition to these ideas, surgeons continue to utilise adjunctive treatments such as peripheral nerve blocks and periarticular injections. Multiple studies demonstrate the efficacy of these therapies. Several authors have published different “cocktails” for their periarticular injections in an attempt to help delineate which components of the cocktail are most important. In addition to deciding on a correct cocktail, how it is delivered is important.

This video will demonstrate a technique that increases the likelihood that the injected solution is placed in the appropriate areas and does not simply bath the tissues. Important components of the technique include the use of a small gauge needle (22) and a control syringe to insure proper placement as well as an aim to target the injections into the periosteum of the femur and tibia and the posterior capsule primarily.

An important goal of total knee replacement is deformity correction. Arthritic narrowing can be accompanied by a fixed shortening of the collateral ligament on the same side of the narrowing. There can also be ligamentous laxity that develops in the opposite compartment. Flexion contracture can develop with tightening of the posterior capsule. Successful total knee replacement requires proper bone resection along with gap balancing and balanced collateral ligament tensioning. Beware of correctable deformities, as the collateral ligament may have kept its resting length and therefore the knee becomes stable after the bone resections are made and the spacer block is inserted to test the stability of the knee in flexion and extension.

In the varus knee, the MCL may be contracted. A medial release of the superficial medial collateral ligament may be necessary. This can be done by stripping the periosteal insertion of the MCL. A stretch may be accomplished by placing a laminar spreader in the narrow medial joint space and opening the space until the MCL stretches from its insertion. This maneuver will require a further increase in polyethylene thickness height of 2 – 4mm. Krackow has also on occasion done a surgical imbrication of the LCL, if it appears attenuated on the lateral side of a severe varus deformity.

For valgus deformities, the LCL, arcuate ligament and popliteus and ITB can be contracted. At this time, most authors recommend preservation of the popliteus tendon as it affects primarily the flexion gap. In extension there has been consensus that the surgeon should release what is tight. This may include the ITB release in a pie-crust fashion, or off the Gerdy's tubercle and then a selective release of the arcuate ligament complex. Krackow has also utilised tightening imbrication of the MCL if it is severely attenuated and lax. This has been used infrequently, however. To avoid overlengthening of the knee by referencing balance off of the lengthened, attenuated MCL in cases of severe valgus deformity, less release is performed and a CCK implant may be used.

For severe flexion contractures, the posterior osteophytes should be first aggressively removed. The posterior joint capsule can be stripped off the distal femur and sometimes the gastrocnemius muscle insertions can be dissected free. After these maneuvers, proximal raising of the joint line by resection of the distal femur can be utilised. In ankylosis with severe flexion contracture, constrained implants will be needed if the proximal resection extends above the insertion of the collateral ligaments.

Recurvatum is a rarely seen deformity that is usually associated with an extraordinarily weak or paretic quadriceps. The joint capsule has become stretched over time. Careful balancing of the knee is necessary. But, if the recurvatum still persists, distally augmenting the femur is an option. And no releases are required.

Computer navigation is an attractive tool for use in total knee arthroplasty (TKA), as it is well known that alignment can affect clinical results. Malalignment of the prosthetic joint can lead to abnormal kinematics, unbalanced soft-tissue, and early loosening. Although there are no long term studies proving the clinical benefits of computer navigation in TKA, studies have shown that varus alignment of the tibial component is a risk factor for early loosening.

A handheld, accerelerometer based navigation unit for use in total knee replacement has recently become available to assist the proximal tibial and distal femoral cuts. Studies have shown the accuracy to be comparable to large, console-based navigation units. Additionally, accuracy of cuts is superior to the use of traditional alignment guides, improving the percentage of cuts within 2 degrees of the desired alignment.

Because the registration is based on the mechanical axis of the knee, anatomic variables such as femoral neck-shaft angle, femoral length, and presence of a tibial bow do not affect the results.

The handheld aspect of this navigation unit allows its use without additional incisions or array attachment. Furthermore, the learning curve and usage time is minimal, supporting its use in primary TKA.

There is a renewed debate regarding the relative importance of (primarily varus-valgus) stability versus alignment in TKA. Some surgeons have posited that stability is of greater importance. Perhaps this is because unstable knees fail immediately whereas mal-aligned knees generally suffer late failure from wear, osteolysis and loosening. Or perhaps some surgeons find soft tissue techniques challenging. Clearly alignment and stability are both necessary for immediate function and long-term durability.

Ligament tensioners are as old as condylar knee arthroplasties. They first appeared when surgeons moved beyond hinged arthroplasties with a goal of melding anatomy and biomechanics- to re-establish stability and correct pathologic deformity. Early techniques stipulated that ligament releases should be performed first, before any bone cuts thus correcting deformity and restoring stability. Crude mechanical instruments were replaced by mechanical devices.

Acknowledging more exacting standards, our ability to hit the target of desired alignment and stability is limited unassisted. As more sophisticated devices have been introduced to help surgeons correct alignment we have not yet discovered the perfect mechanical, electronic, navigated or laser guided “tensioner”. We still struggle to divine the “best” alignment. The principle however endures, that integrating stability and alignment, if with nothing more than a “cognitive tensioner” is essential to optimal short and long term arthroplasty function.

In a study by Dickstein, one-third of total knee patients were not satisfied even though they were all thought to have had successful results by their orthopaedic surgeons. Noble and Conditt's study showed 14% of patients dissatisfied with their outcome with more than half expressing problems with routine activities of daily living. This occurs despite improvements in instrumentation to obtain proper alignment and implants with excellent kinematics and wear characteristics. Perhaps this dissatisfaction is a result of subtle soft tissue imbalance. Soft tissue imbalance can result in almost a third of early TKR revisions. Soft tissue balancing techniques still rely on subjective feel for appropriate ligamentous tension by the surgeon. Surgical experience and case volume play a major role in each surgeon's relative skill in balancing the knee properly.

New technology of “smart trials” with embedded microelectronics, used in the knee with the medial retinaculum closed, can provide dynamic, intraoperative feedback regarding quantitative compartment pressures and component tracking. While visualising a graphical interface, the surgeon can assess the effect of sequential soft tissue releases performed to balance the knee. These smart trials also have imbedded accelerometers used to confirm that one is balancing a properly aligned knee and to provide the option of doing small bony corrections rather than soft tissue releases to obtain balance.

A multi-center study using smart trials is demonstrating dramatically better outcomes at six months.

Lavage and preparation of cancellous bone surface is essential to ensure adequate fixation of components in cemented total knee arthroplasty (TKA). Commonly used techniques for bone preparation such as pulse lavage, apart from adding to the cost, may cause local loss of loose cancellous bone and may even drive contaminants deeper into the tissue when used during TKA. We describe a simple, inexpensive and effective tool of using a sterilised toothbrush for preparing bone surface during cemented TKA.

During the development and early use of the First Generation of Universal Total Knee Replacement Instruments, those instruments supplied with the PCA knee and also available for use with the Kinematic and Total Condylar knees, David Hungerford and I noticed our imperfection in balancing some varus and valgus deformed total knee patients.

We decided to start ligament tightening procedures to address this problem

I became impressed with the potential difficulty simply of grasping the medial capsular ligamentous sleeve and pulling it distally on the proximal tibia so that it could be stapled in place. I thought that use of a suture and then incorporation of that suture with a staple or screw could enhance the fixation.

The tissue we were working with and are now talking about is rather thin, one to two millimeters, flat and broad with longitudinal fibers running in a caudad-cephalad direction.

I wanted some way to grab these longitudinal fibers and exert a distal pull without having the suture material pull through. This suggested the use of a locking loop, analogous to what I had seen in my training when locking stitches were commonly used on different layers of wound closure. I developed in my head the picture of a row of locking loops and then saw the cross-over to the other side which revealed the entire structure with trailing tails.

At this writing, I am uncertain of the year, but I am thinking it was 1982.

Soon after that I illustrated it with OR suture thru paper and then began using it in surgery.

I felt that publication would require studies of relative pull-out strength, and we added an injection study to look at possible influence of the tissue vascularity.

For tensile strength we used #5 Ethibond in bovine Xenograft material, stapled and sewn to wood. In summary, different from individual stitches or stapling without stitching, The K-stitch fails at the suture material and not buy pulling the tissue. This statement is true when the suture reasonably matches the heft or thickness and strength of the soft tissue. Otherwise one is dealing with suture that is overpoweringly stronger than the tissues being fixed or held.

Patellofemoral complaints are the common and nagging problem after Total Knee Arthroplasty. Crepitus occurs in 5% to over 20% of knee arthroplasty procedure depending on the type of implant chosen. It is caused by periarticular scar formation with microscopic and gross findings indicating inflammatory fibrous hyperplasia.

Crepitus if often asymptomatic and not painful, but in some cases can cause pain. Patella “Clunk Syndrome” is less common and represents a when the peripatella scarring is abundant and forms a nodule which impinges and “catches” on the implants intercondylar notch. Patella Clunk was more common with early PS designs due to short trochlear grooves with sharp transition into the intercondylar notch. Clunks are very infrequent with modern PS implants. This Syndrome has been reported in CR implants as well.

Thorough debridement of the synovium and scarring at the time of Arthroplasty is thought to reduce the occurrence of crepitus and clunks. Larger patella with better coverage of the cut bone may also be helpful.

The diagnosis can be made on history and physical exam. X-rays are also helpful to assess patella tracking. MRI or ultrasound can be used to identify and confirm the diagnosis but this is not mandatory.

Painful crepitus and clunk syndrome that fail conservative management of NSAIDS and physical therapy may require surgery. Both crepitus and clunk can be treated with arthroscopic removal of the peripatella scar. Patella maltracking should also be assessed and treated. While recurrence may occur it is uncommon.

In primary TKA, non- or semi-constraint TKA implants might have their limitations in the absence of collateral ligaments, severe deformity, large osseous defects and gross flexion - extension instability. Although most primary TKA indications can be solved with modular, non-hinged implants, an adequate balancing might require a relevant soft tissue release. This consequently adds complexity and operative time with less predictable results in the elderly patient. The current literature reporting on short to mid-term results of rotating hinged implants in primary osteoarthritis shows some quite diverse results and consequently different interpretations of this implant type in primary knee arthroplasty. Although some authors were able to show good and excellent clinical results in 91% of patients and consequent survival rates of a rotating hinge implant after 15 years up to 96% in primary indications, others found high complication rates of up to 25% of all operated patients, which remains unclear for us and is inconsistent with our clinical results in primary and revision TKA in over 30 years of experience with the Endo-Model rotating hinge implant.

Our potential indications in the elderly for a rotating- or pure-hinged implant in primary TKA include: Complete MCL instability, Severe varus or valgus deformity (>20 degrees) with necessary relevant soft tissue release, Relevant bone loss including insertions of collaterals, Gross flexion-extension gap imbalance, Ankylosis, One staged implantation with specific antibiotics after PJI.

Due to general limited soft tissues or hyper laxity, patients with neuropathic joints, or lack of extensor mechanism should be considered to a complete hinged implant. The ENDO-model hinge has only been minimal adapted since its development in the 70's, including fully cemented long stems, in modular and non-modular versions. We strictly reserve a rotational hinge in primary indications for patients >70 years with a combined varus alignment, whereas in severe valgus deformities, a complete hinged implant version should be used for our implant design.

Anterior knee pain is a frequent complaint of dissatisfied total knee arthroplasty patients. We hypothesize that the need to use the extensor mechanism to stabilise the knee during activity is a cause of anterior knee pain. Studies have shown that TKA patients often walk with a “quadriceps avoidance” gait, which may explain the phenomenon of anterior knee pain.

Most TKA prostheses are designed to allow AP motion. This feature in knee implant design is to prevent the “kinematic conflict” that was predicted with the crossed four-bar-link model of knee motion, which holds that progressive posterior contact of the femur on the tibia (rollback) with flexion was obligatory for knee range of motion. It has been stated that preventing this motion overly “constrained” the knee and could lead to loosening and wear.

Paradoxical motion has been seen with video fluoroscopy in knees after TKA. This motion is an anterior translation of the femur on the tibia early in knee flexion and is called paradoxical because it occurs opposite to the expected rollback. In fact, paradoxical motion is a consequence of the “unconstrained” articulation of the femoral component on the tibial component.

During gait, just after heel strike as the foot is assuming a flat position on the floor, there is a significant vector of force from posterior to anterior. This vector has been calculated as 33% of body weight for walking at normal speed and could lead to a significant displacement of the femur forward on the tibia. It is countered by 1) the slope of the proximal tibia; 2) the articulation of the femur in the concavity of the tibial (with the firmly attached meniscus that deepens the concavity) on the medial side; and 3) the body mass vector combined with that of the contracting quadriceps.

If a total knee prosthesis allows the femur to move forward, the posterior-to-anterior force just after heel strike acts to move the femur forward on the tibia (paradoxical motion). The patient, in an attempt to stabilise the knee, uses increased quadriceps contraction to prevent the forward motion of the femur. The forces required are significant and are not only found in the patella-femoral articulation but all through the retinaculum that covers the anterior part of the femur. As the extensor mechanism tires, patients begin using a quadriceps avoidance gait to adapt to the weakening extensor, and after a period of activity, the stress on the retinaculum leads to pain.

AP stability can be improved through implant design by preventing AP motion through conformity of the femoral and tibial components. We have used a medially conforming ball-in-socket prosthesis as a revision component for patients with anterior knee pain, and have achieved resolution of the pain. Patients demonstrate a “posterior sag” at approximately 20 degrees of flexion (the degree of flexion that has the maximum posterior-to-anterior force during gait). When treated with a brace appropriate for stabilisation of the knee after PCL reconstruction, patients experienced a marked decrease in symptoms and this predicts a good result from revision surgery.

Expedient removal of a well fixed total knee replacement relates to obtaining access to the fixation surfaces so as to disrupt the bone implant or bone cement interfaces. The first point is wide exposure, most commonly with a modification of a quads snip procedure. Fixation surface disruption is achieved with a combination of saws, high speed burrs and osteotomes. More extensive metaphyseal fixation may require osteotomy to achieve access. Tubercle osteotomy is one option. We more commonly utilise a medial tibial cortical osteotomy, which preserves the extensor function. Video techniques will be presented.

Metaphyseal bone loss is common with revision total knee arthroplasty (TKA). The causes of bone loss include: osteolysis, loosening, infection, iatrogenic or a combination. Small defects can be treated with screws and cement, bone graft, and non-porous metal wedges or blocks. Large defects can be treated with bulk structural allograft, impaction grafting, or highly porous metal cones or augments. The AORI classification of bone loss in revision TKA is very helpful with preoperative planning. Type 1 defects do not require augments or graft—use revision components with stems. Type 2 defects should be treated with non-porous metal augments—wedges or blocks. Type 3 defects require a bulk structural allograft or large highly porous metal cone. Trabecular metal (TM) metaphyseal cones are a unique solution for large bone defects. There are both femoral (full or partial) and tibial (full or stepped) TM cones available. These cones substitute for bone loss, improve metaphyseal fixation, help correct malalignment, restore joint line, and perhaps, permit use of a shorter stem. The technique for these cones involve sculpturing of the remaining bone with a high speed burr and rasp, followed by press-fit of the cone into the remaining metaphyseal bone. The interface is sealed with bone graft and putty. The fixation and osteoconductive properties of the outer surface allow ingrowth and hopefully long term biologic fixation. The revision knee component is then cemented into the porous cone inner surface, which provides superior fixation compared to deficient metaphyseal bone. The advantages of the TM cone compared to allograft include: technically easier; biologic fixation; no resorption; and (?) lower risk of infection. The disadvantages include: difficult extraction and relatively short-term follow-up. The author has reported the results of 33 TM cones (9 femoral, 24 tibial) implanted in 27 revision cases at 2–5.7 years follow-up. One knee (2 cones) was removed for infection. All but one cone showed osseointegration. TM cones are a promising method for the reconstruction of large bone defects in revision TKA.