Management of 4-part fractures of the proximal humerus continues to challenge orthopaedic surgeons, shoulder surgeons, and trauma surgeons. Truly displaced 4-part fractures typically require surgery if the patient is medically able to undergo a surgical procedure. However, outcomes following surgery are not always as predictable as we would like. Results following hemiarthroplasty have led to more predictable pain relief than predictable functional recovery relying exclusively on the fate of tuberosity healing. Tuberosity healing failure leads to nearly universal catastrophic results with pain, dysfunction, and pseudoparalysis. Furthermore, conversion of failed hemiarthroplasty to reverse total shoulder arthroplasty leads to the highest incidence of complications and poorest outcomes of all groups of patients undergoing reverse total shoulder replacement. This is countered by the knowledge that if tuberosity healing occurs the outcome can be reliable with regard to pain relief and functional restoration.

Reverse total shoulder arthroplasty, on the other hand, has emerged as a preferred surgical option for many surgeons due to the issues following hemiarthroplasty. The increased prevalence of RTSA for the management of 4-part fractures has come without overwhelming evidence that outcomes are superior especially in light of the increased cost, life-time weight bearing restrictions, and uncertain long-term durability. Long-term follow-up of patients treated with RTSA for 4-part fracture has shown concerning degradation of function and outcomes and remains a valid concern about the long-term durability. We must remain diligent therefore in continuing to better understand which fractures should be treated non-operatively and those that may be amenable to anatomic hemiarthroplasty and finally those which may be better served by using a reverse total shoulder replacement.

Age is the most accurate surrogate for bone density and poor bone density is the reason for many fracture repairs to fail. Hemiarthroplasty has demonstrated consistently inconsistent results in terms for restoration of function. Most recently, with the evolution of reverse prostheses, prospective studies which are, in many cases, randomised and Level 2, have clearly shown reverse prostheses to be the most consistently reliable treatment in the patient noted above. It is with a high degree of certainty that we can inform such a patient that their function will be restored and their pain minimal with such treatment.

Stemless shoulder arthroplasty implants for the proximal humerus provide cementless metaphyseal prosthetic fixation. A near-perfect anatomic restoration of the proximal humeral articular surface is possible with this canal-sparing design—avoiding the risks associated with humeral stems and preserving bone for later revision.

When compared with proximal humeral resurfacing, stemless arthroplasty avoids the potential technical errors that may lead to oversized implants, abnormal shift of the glenohumeral joint center of rotation, and excessive strain on the native rotator cuff.

While canal-sparing stemless implants represent a new concept in shoulder arthroplasty without mid- and long-term results, the failures associated with resurfacing humeral arthroplasty have been documented in the literature. Unlike a stemless component, use of a resurfacing technique (and hence preservation of the humeral head) makes glenoid prosthetic implantation challenging and often impossible.

The modern humeral head resurfacing was developed by Stephen Copeland, M.D. and introduced in 1986 as an alternative to stemmed humeral implants. At the time, first and second generation monoblock and modular stems with non-offset humeral heads posed many challenges to the surgeon to recreate the pre-morbid humeral head anatomy during anatomic TSA. The consequences of non-anatomic humeral head replacement were poor range of motion, increased native glenoid or glenoid component wear and premature rotator cuff failure. Additionally, the early generation humeral stems were very difficult to extract when revision was needed. The original stemless devices were cup resurfacing implants that were designed based on the early hip experience. The Copeland resurfacing device offered the ability to better match native humeral head anatomy and was considered less invasive and easier to revise. Glenoid exposure required more extensive dissection but TSA could be successfully completed.

Clinical results for motion, function and outcome scores are similar to stemmed implants. The survivorship of the implants is also on par with other available implants and loosening has not been an issue. Stress shielding is not reported. Multiple manufacturers offered similar products all designed to try to predictably recreate the pre-morbid anatomy and to make insertion easier.

Critical review of resurfacing arthroplasty radiographs has raised concern about the challenges of placing the implant with proper sizing and position. Most surgeons have implanted resurfacing implants as hemiarthroplasties. The development of anatomic TSA implants has allowed surgeons to better recreate the normal pre-morbid anatomy of the humerus. Newer stem designs are convertible or easily removable. This counters many of the original design benefits of resurfacing. The primary reason for revision of resurfacing implants is malposition followed by glenoid arthrosis and rotator cuff failure. Revision surgery after resurfacing has had mixed results.

Stemless implants were introduced in Europe 13 years ago. Stemless devices share the benefits of resurfacing as minimally invasive and easier to revise. The added benefit of better glenoid access allows the surgeon to implant a glenoid. Most available implants have minimal follow-up. Mid-term follow-up of one design has demonstrated good fixation and loosening is uncommon. No studies are available that critically evaluate the surgeon's ability to recreate normal pre-morbid anatomy, whether revision arthroplasty is bone preserving and if results of revision will improve.

Reverse TSA initially followed Grammont's dictum that the center of rotation (COR) must be in the bone (“medial” COR). Others have argued for a more lateral COR, which can be a challenge if glenoid bone stock has been medially eroded. When bone loss must be made up, and/or the COR lateralised, the options include use of bone graft or use of metal.

Metal constructs produce a cantilever-loading situation, with substantial bending moments applied to the bone-implant junction. Use of bone graft allows remodeling with living bone, so that ultimately the forces are applied to the bone-implant junction in a more compressive pattern.

The author's preference is to have at least 30% of the circumference of the baseplate contact living bone while the rest may be made up with bone graft which can remodel. It is important to have a deep keel penetrate the cortex medially.

Lateralization of the reverse arthroplasty may be desirable to more effectively tension the remaining rotator cuff, decrease scapular notching, improve the cosmetic appearance of the shoulder, and improve stability as well as the arc of motion prior to impingement. There are two primary options to lateralise a reverse shoulder arthroplasty: bone graft with a long post (BIO-RSA) vs. using metal. The two metal options generally include a thicker glenosphere or a thicker glenoid baseplate.

Potential benefits of a BIO-RSA include lateralization of the glenoid center of rotation but without placing the center of rotation lateral to the prosthetic-bone interface. By maintaining the position of the center of rotation, the shear forces at the prosthesis-bone interface are lessened and are converted to compressive forces which will minimise glenoid failure.

Edwards et al. performed a prospective study on a bony increased offset reverse arthroplasty. Among the 18 shoulders in the BIO-RSA group, the incidence of notching was 78% compared to controls 70%. The graft completely incorporated in 12 (67%), partially incorporated in 4 (22%), and failed to incorporate in 2 (11%).

Frankle et al. reported on the minimum 5-year follow-up of reverse arthroplasty with a central compression screw and a lateralised glenoid component. The survivorship was 94% at 5 years. There were seven (9%) cases of scapular notching and no patient had glenoid baseplate loosening or baseplate failure. The authors noted that the patients maintained their improved function and radiographic results at a minimum of five years.

In summary, lateralisation of the glenosphere is an attractive option to improve the outcome of reverse arthroplasty. Benefits of lateralisation with metal rather than bone graft include elimination of concern over bone graft healing or resorption. In addition, the procedure has the potential to be more precise with the exact offset amount known pre-operatively as well as improved efficiency of the procedure. Preparing the graft takes additional OR time and there is variable quality of the bone graft.

Clinical nerve injury has been reported in 0.6–4.8% of shoulder arthroplasties. Classical teaching is that 70–85% of injuries recover. Despite recovery of motor function, overall shoulder function may be negatively affected and residual pain is common. Complex regional pain syndromes may develop and become permanent. Consequently, methods to limit nerve injury have been investigated.

In the early 2000's I became concerned about the incidence of nerve injuries in my arthroplasty practice. I became intrigued with the idea of peripheral nerve monitoring as a method to alert the surgeon intra-operatively about impending nerve insults so that evasive measures could be taken to prevent any clinically significant nerve injuries. The results of our first 30 consecutive patients were published in JSES in 2007. Seventeen patients (56.7%) had 30 episodes of nerve dysfunction (i.e. nerve alerts) during surgery. Twenty-three of thirty alerts (76.7%) returned to normal after repositioning the arm to a neutral position. Post-operative EMG was positive in 4 of 7 (57.1%) patients who did not have a return to normal motor latency intra-operatively and in 1 of 10 (10%) patients whose intra-operative nerve function did return to normal. None had clinical nerve injuries. This early experience indicated that nerve injury was potentially more common than previously thought but intra-operative nerve monitoring seemed to have a relatively high false positive rate.

Our group subsequently studied 440 shoulder arthroplasty cases. The protocol used to identify a nerve alert was made more restrictive than the first study as an attempt to decrease the false positive rate. In this larger group, nerve alerts occurred in 185 cases (42.0%), and 37 (8.4%) cases did not have signals return to above the alert threshold at closure. There were no permanent post-operative nerve injuries and 5 transient nerve injuries (1.1%). Cases in which MEP amplitudes remained below alert threshold were significantly more likely to have a post-operative nerve injury (p = 0.03). There were no false negatives, (i.e. a post-operative nerve injury occurred while MEPs were normal at closure), making sensitivity 100%. There were 32 false positives, leading to a specificity of 92.6%, a positive predictive value (PPV) of 13.5%, a negative predictive value (NPV) of 100%, and an accuracy (ACC) of 92.3%. In my opinion, the high false positive rate and the low PPV make the technique difficult to justify for routine clinical use.

Experience has demonstrated in the hip and knee, related to total joint replacement arthroplasty, polymethyl methacrylate cement fixation can provide problems in terms of loosening, fragmentation, particulate wear and ultimate failure.

These same problems have been recognised in total shoulder arthroplasty related to cement fixation of the glenoid. While cement fixation of the humeral component has proven much less problematic, there has been a swelling towards avoidance of using cement to secure the humeral component for fear of difficulty if revision is required.

Surprisingly, with the high incidence of lucent lines, bone resorption and frank loosening, representing the most common source of failure in total shoulder arthroplasty, cementless fixation of the glenoid has not been, until now, embraced.

The advent of reverse total shoulder arthroplasty has demonstrated the ability for secure cementless fixation to provide long-lasting secure implant retention in implants which have inherently higher shear and stress forces passing through the implant/bone interface. In anatomic total shoulder arthroplasty a woven tantalum anchor (Trabecular Metal) has proven to demonstrate secure cementless fixation as well.

This presentation will discuss the use of trabecular metal anchored glenoid implants with and without additional screw fixation for anatomic and convertible reverse arthroplasty baseplates. Avoidance of complications with successful long-lasting outcomes requires meticulous surgical attention to detail.

Glenoid bone loss is not an uncommon challenge in both primary shoulder arthroplasty surgery and revision surgery. Walch described the classification of glenoid morphology and this has led to an understanding of the expanded role for bone grafting, patient-specific implants and reverse prostheses. While bone grafting of the glenoid in conventional arthroplasty has been shown to be successful in some patients it is more routinely used in combination with reverse prostheses. More recently, augmented glenoid components have been developed for both conventional and reverse arthroplasty, though follow-up is insufficient to confirm their durability at this time.

Subscapularis tenotomy (SST) has been the preferred approach for shoulder arthroplasty for decades but recent controversy has propelled lesser tuberosity osteotomy (LTO) as a potential alternative. Early work by Gerber suggested improved healing and better outcomes with LTO although subscapularis muscular atrophy occurred in this group as well with unknown long-term implications. However, we previously performed a biomechanical study showing that some of the poor results following tenotomy may have been due to historic non-anatomic repair techniques. Surgical technique is critical to allow anatomic healing – this is true of both SST or LTO techniques. A recent meta-analysis of biomechanical cadaveric studies showed that LTO was stronger to SST at “time-zero” with respect to load to failure but there were no significant differences in cyclic displacement.

A recent study evaluated neurodiagnostic, functional, and radiographic outcomes in 30 patients with shoulder arthroplasty who had SST. The authors found that the EMG findings were normal in 15 patients but abnormal in the other 15 and that these abnormalities occurred in 5 muscle groups (not just the subscapularis). In another study, patient outcomes were inferior in those patients who had documented subscapularis dysfunction following SST compared to patients who had LTO (none of whom had subscap dysfunction). The literature is not clear, however, on ultimate outcomes based on subscapularis dysfunction post-arthroplasty with some studies showing no difference and others showing significant differences.

Modern total shoulder arthroplasty seeks to produce a construct that reproduces the kinematics and stability of the native glenohumeral joint. The latest 4th generation implants are modular, adaptable, and capable of use as either anatomic or reverse shoulder arthroplasty components. During surgery, these implants are “universal”; post-operatively, they are “convertible”.

Recent work has demonstrated that reverse shoulder arthroplasty components may indeed be the emerging standard of care for most (if not all) shoulder arthroplasty indications.

As this new frontier develops, the use of a convertible/universal implant creates the flexibility to individually choose the best surgical option for each patient.

Arthroplasty implant modularity enables the surgeon to adapt the joint replacement construct to the patient's requirements, and often facilitates revision procedures. Total shoulder arthroplasty humeral modularity exists for many implant systems. Glenoid modularity with convertibility between anatomic and reverse shoulder arthroplasty is a recent development. Glenoid modularity is very useful when reconstructing glenoid bone deficiencies, or in providing a method for reverse shoulder arthroplasty joint lateralization.

The live surgery will demonstrate a bio-reverse total shoulder arthroplasty (bRTSA). The humeral component is a modular press fit stem that can accommodate either reverse or anatomic metaphyseal components. The metaphyseal components can be exchanged without removing the stem or changing the humeral height. The glenoid base has three components. The trabecular titanium peg is available in two diameters, and four lengths for each diameter. The peg is fixed to a metal base plate via Morse taper. In revision settings, these components can be easily dissociated in situ, and a coring drill inserted over a well-fixed peg allows removal with minimal bone loss. Either a polyethylene component, or glenosphere can be attached to the baseplate to complete the glenoid construct.

An innovative set of instruments have been developed to reliably prepare the glenoid and humeral bone graft. While the live surgery will demonstrate the grafting technique in a bRTSA, it can also be used to reconstruct glenoid deficiencies (eg, Walch B2). Implants have been developed to solve these issues, but often do so at the expense of very limited glenoid bone stock. Bone grafting actually creates a net increase in glenoid bone stock that may improve implant durability, and decrease revision complexity. The technique is quite simple and adds approximately ten minutes to operative time. I have used this technique for 5 years with no cases of graft failure.

Infection prevention in shoulder arthroplasty is an evolving challenge as further understanding of the pathogens becomes available. Infection rates for reverse TSA is higher than anatomic TSA. Standard decolonization protocols from our hip and knee colleagues has decreased the acute post-operative infection risk to less than 1%. By identifying at risk populations anti-MRSA precautions including intranasal antibiotics and anti-bacterial soaps for pre-surgical skin preparation have reduced the incidence of staphylococcus infections. The emerging understanding of propionibacterium acnes (P. acnes) as a primary pathogen in late shoulder periprosthetic joint infection (PJI) has led to new recommendations including pre-operative skin cleansing with 5% benzoyl peroxide to reduce infection risk. Pre-operative IV antibiotic is recommended and chlorhexidine skin prep for surgery.

In the operating room, the concern is the surgeon's exposure to skin and sebaceous glands where P. acnes is prevalent. After skin incision the surgeon should use a new blade for deep incision. Application of vancomycin powder to the subcutaneous tissue may be beneficial after incision to treat potential contamination from the incision through skin. Glove change prior to handling implants and thorough irrigation before implantation is prudent. The role of antibiotic loaded bone cement for infection prevention remains unproven. Topical vancomycin powder at closure is a low cost option and has shown benefit in spine surgery but efficacy is unproven in the shoulder. Silver impregnated wound dressings may also prevent infection and are a convenient option for patient care with regards to bathing.

Preventing infections in shoulder arthroplasty, particularly P. acnes, remains a challenge. A significant number of revision TSAs are found to have positive cultures for P. acnes creating a significant burden for patients and surgeons.

Periprosthetic joint infection (PPJI) following shoulder arthroplasty is uncommon, with an overall rate of 0.98%. However, the rates following revision arthroplasty and reverse arthroplasty are much higher. Given the rapid increase in the prevalence of shoulder arthroplasty and the increasing revision burden, the cost of PPJI to society will likely increase substantially. The most common organisms found in PPJI following shoulder arthroplasty are Staphylococcus aureus, coagulase-negative Staphylococcus, and Propionibacterium acnes (P. acnes). P. acnes is especially common in males. Traditional testing for PPJI includes aspiration, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and c-reactive protein (CRP). Aspiration often yields a dry tap and when fluid is obtained for culture, a positive result is helpful but a negative result does not rule out PPJI. Although WBC, ESR, and CRP are often positive with PPJI in the lower extremity, they are most often negative in shoulder PPJI. Although bone scans and WBC labeled scans are used, they are expensive and have low sensitivity and specificity.

New testing and techniques have been reported in an attempt to improve sensitivity and specificity for PPJI. These techniques can be divided into tests on serum, synovial fluid, and tissue. Serum Interleukin-6 (IL-6) is highly specific (94%) for shoulder PPJI but has low sensitivity (14%). Synovial fluid can be tested for leukocyte esterase using a simple and cheap technique. In lower extremity PPJI it has shown to be helpful. It is not as helpful in shoulder PPJI with 30% sensitivity and 67% specificity. Alpha defensin has been reported to be more sensitive (63%) and as specific (95%) as traditional techniques but still lacks predictive value. Testing for specific cytokines (IL-2, IL-6, TNF- α) within synovial fluid is not widely used as yet but has shown promise with 80% sensitivity and 90% specificity. Obtaining tissue for culture and other testing is probably the most reliable way of confirming PPJI for the shoulder. Frozen sections taken at the time of revision can be helpful but is very pathologist dependent and institution specific. With a dedicated musculoskeletal pathologist, the finding of 10 or more WBCs per high powered field has been reported to be 72% sensitive and 100% specific for P. acnes and 63% sensitive and 100% specific for other organisms. Cultures from arthroscopic tissue biopsy have also been found to have high sensitivity (100%) and specificity (100%). Genetic testing of tissue biopsy specimens (PCR/NGS) has recently been reported and shows great promise. The significance of positive cultures and other tests, especially for P. acnes is unclear. There is a high rate of positive intra-operative cultures in primary cases of shoulder arthroplasty. In addition, intra-operative cultures taken at the time of revision, even in cases in which infection is not suspected, are frequently positive for P. acnes with weak correlation with rates of post-operative clinical infection.

In conclusion, shoulder PPJI is a difficult problem to deal with. The definition of shoulder PPJI is currently unclear and further study is needed. There is no ideal test to confirm it. A reasonable approach is to aspirate for culture, and perform serum tests for WBC, ESR, and C-reactive protein. If any of these is positive in the setting of a painful arthroplasty, PPJI should be assumed until proven otherwise. Operative tissue cultures are probably the most reliable test but the clinical significance is not always obvious. Synovial fluid cytokine profiles and tissue PCR/NGS show promise for the future.

There continues to be significant debate on the optimum treatment of the infected shoulder arthroplasty. Infection after shoulder arthroplasty is an infrequent but devastating complication with a reported incidence from 0 to 4%. The most common organism responsible for infection following rotator cuff surgery, instability surgery, ORIF proximal humerus fractures, and shoulder arthroplasty is P. acnes. A thorough history is important because many patients have a history of difficulty with wound healing or drainage. P. acnes typically does not start to grow until day 5, therefore it is critical to keep cultures a minimum of 10 to 14 days.

Diagnosis can be challenging, particularly among patients undergoing revision surgery. The majority of patients with a low grade infection do not have overt signs of infection such as erythema or sinus tracts. Pre-operative lab values as well as intra-operative pathology have been shown to be unreliable in predicting who will have positive cultures at the time of revision surgery.

There are a number of options for treating a patient with a post-operative infection. Essential variables include the timing of infection, status of the host, the specific organism, status of implant fixation, and the status of the rotator cuff and deltoid. One of the most frequently employed options for treating the infected shoulder arthroplasty is two stage re-implantation. However, the rate of complications with this technique as well as residual infection remains high.

Pain management following surgery continues to challenge patients, physician-extenders, and surgeons. A recent survey of 300 patients following surgery found that 86% experienced pain following surgery with 75% describing moderate or severe pain. Pain management in 2017 has to better address patient's needs as Pain has become the “5th Vital Sign” and is used in many patient reported outcomes (for better or worse). Multimodal therapy has been defined as “Synchronous administration of ≥ 2 pharmacological agents or approaches, each with a distinct mechanism of action”.

Mounting evidence supports the use of a multimodal approach to peri-operative pain management in all surgical subspecialties. A recent systematic review of intravenous ketamine showed a reduction total opioid consumption and an increase in the time to first analgesic dose needed across all studies. Gabapentin and pregabalin have both been shown to dramatically reduce the use of opioid consumption by 30%. We have worked with our anesthesia team and developed a multimodal analgesia program that includes ketorolac 10mg 3 tabs po qd × 3 days, then 10mg 2 tabs po × 2 days; gabapentin 300mg (<65 year old) or 100mg (>65 year old) 3 tabs po × 3 days; oxycodone 5mg po q 4–6 hours prn breakthrough pain and Tylenol 500mg 1–2 tabs po q 6 hours prn.

Total shoulder arthroplasty has gone through several generations, as instruments and implant designs have given surgeons both more options in the alignment of the components and more guidance in the best choices to make. However, while the measurement of alignment has become more sophisticated, the importance of particular aspects of alignment to actual patient comfort and function has been less completely characterised.

Overstuffing of the joint and proud humeral heads have been most associated with clinical failure. The efforts to avoid this can be divided into two camps:

The anatomic school, who believe an experienced surgeon can divine the correct anatomy that existed before the distortions of arthritis began, and that the surgeon should make free-hand cuts and alignments to restore the normal anatomy.

The cutting-guide school, who believe that average versions and positions avoid error and that soft-tissue balancing requires occasional deviations from “normal” anatomy.

Challenging shoulder cases will be presented and discussed by a panel of experts in the field. Emphasis will be on restoring glenohumeral anatomy, repairing or reconstructing the rotator cuff, and supervising rehabilitation. Different surgical options and new emerging technologies will be reviewed while highlighting the pros and cons of each.

Glenoid exposure is the name of the game in total shoulder arthroplasty. I can honestly say that it took me more than 5 years but less than 10 to feel confident exposing any glenoid, regardless of the degree of bone deformity and the severity of soft-tissue contracture. This lecture represents the synthesis of my experience exposing some of the most difficult glenoids. The basic principles are performing extensive soft-tissue release, minimizing the anteroposterior dimension of the humerus by osteophyte excision, making an accurate humeral neck cut, having a plethora of glenoid retractors, and knowing where to place them.

The ten tips, in reverse order of importance are: 10.) Tilt the table away from operative side—this helps face the surface of the glenoid, especially in cases of posterior wear, toward the surgeon. 9.) Have multiple glenoid retractors—these include a large Darrach, a reverse double-pronged Bankart, one or two blunt Homans, small and large Fukudas. 8.) Remove all humeral osteophytes before attempting to retract the humerus posteriorly to expose the glenoid—this helps to decrease the overall anteroposterior dimension of the humerus and allows for maximum posterior displacement of the humerus. 7.) Make an accurate humeral neck cut—even 5mm of extra humeral bone will make glenoid exposure difficult. 6.) Optimal humeral position—it has been taught that abduction, external rotation, and extension is the optimal position. It may vary with each case. Therefore, experiment with humeral rotation to find the position that allows maximum visualization. This is often the position that makes the cut surface of the humerus parallel to the surface of the glenoid. 5.) Optimal retractor placement—my typical retractor placement is a Fukuda on the posterior lip of the glenoid, a reverse double-pronged Bankart on the anterior neck of the scapula, and a blunt Homan posterosuperiorly. Occasionally, a second blunt Homan anteroinferiorly is helpful, particularly in muscular males with a large pectoralis major. 4.) Laminar spreader for lateral humeral displacement—this can be helpful for posterior capsulorrhaphy or for posterior glenoid bone grafting. 3.) Maximal humeral capsular release—the release of the anterior capsule from the humerus must go well past the 6 o'clock position and up the posterior surface of the humerus. This aides in humeral exposure but also allows for more posterior displacement of the humerus during glenoid exposure. 2.) Anteroinferior capsular release or excision—extensive anteroinferior release or excision (my preference), allows for maximal posterior humeral displacement and also restores external rotation. 1.) Posterior or posteroinferior capsular release—release of the posteroinferior corner of the capsule from the glenoid results in a noticeable increase in posterior humeral retractability. In cases without substantial posterior subluxation, extensive release of the entire posterior capsule is performed.

Following these steps will help the surgeon to gain adequate glenoid exposure, even in the most difficult cases.

Reverse total shoulder arthroplasty (TSA) has demonstrated success in restoring active elevation for patients with rotator cuff dysfunction (with or without arthritis). However, recovery of active external rotation after reverse TSA has demonstrated variable success. Transfer of the latissimus dorsi has shown promise in restoring active external rotation in those patients with profound external rotation deficits.

The combined latissimus transfer and reverse TSA procedure is intra-operatively challenging and fraught with post-operative complications. Technical details and precise indications are necessary to produce the best chance of success with this operation.

The age spectrum for patients undergoing shoulder arthroplasty is broadening. Many younger patients now demonstrate shoulder pathology precluding non-arthroplasty reconstruction. The senior population is living longer and “younger”. Therefore, the demands of this patient population to participate in an active lifestyle are growing. Patients with osteoarthritis, cuff tear arthropathy, post-traumatic arthropathy, avascular necrosis, and even forms of inflammatory arthropathy present seeking not only return to simple activities of daily living but the ability to participate in aerobic recreational activities and even work activities which can stretch the limits of shoulder arthroplasty in the physiologic environment of the shoulder.

This presentation will provide an overview of patient demands, concerns and activity level following shoulder arthroplasty. We will provide a prospective of allowable, recommended and discouraged activities depending on the underlying source of pathology in the type of arthroplasty implants employed. An overview of our four phases of rehabilitation protocol will be presented focusing on phase four, “work in sports hardening”.

After shoulder arthroplasty many pain generators may continue to play a role and these might otherwise be missed in a patient where the post-operative radiograph looks fine. Such conditions might include pain from an adjacent location such as the AC joint, or stress fracture of the acromion with reverse prostheses. Unrecognised infection or rotator cuff tear are also factors to consider. Moreover, anxiety and depression may be relevant to the outcome of shoulder arthroplasty.

Revision of the humeral component in shoulder arthroplasty is frequently necessary during revision surgery. Newer devices have been developed that allow for easy extraction or conversion at the time of revision preserving bone stock and simplifying the procedure. However, early generation anatomic and reverse humeral stems were frequently cemented into place. Monoblock or fixed collar stems make accessing the canal from above challenging. The cortex of the Humerus is far thinner than the femur and stress shielding has commonly led to osteopenia. Many stem designs have fins that project into the tuberosities putting them at risk for fracture on extraction.

Extraction starts with an extended deltopectoral incision from the clavicle to the deltoid insertion. The proximal humerus needs to be freed from adhesions of the deltoid and conjoined tendon. The deltopectoral interval is fully developed. Complete subscapularis and anterior capsular release to the level of the latissimus tendon permits full exposure of the humeral head. After head removal the stem can be assessed for loosening and signs of periprosthetic joint infection. The proximal bone around the fin of the implant should be removed from the canal. If possible, the manufacturer's extractor should be utilised. If not, then a blunt impactor can be placed from below against the collar of the stem to assist in extraction. With luck the stem can be extracted from the cement mantle. If there is no concern for infection, the cement-in-cement technique can be used for revision. Otherwise, attempts should be made to extract all the cement and cement restrictor, if present. The small cement removal tools from the hip set can be used and specialised shoulder tools are available. An ultrasound cement removal device can be very helpful. The surgeon must be particularly careful to avoid perforation of the humeral cortex. This is especially important when near the radial nerve as injury can occur

When a well-fixed stem is encountered, an osteotomy of the proximal humerus is necessary. The surgeon can utilise a linear cut with an oscillating saw along the bicipital groove for the length of the implant. An osteotome is used to crack the cement mantle allowing stem extraction. Alternatively, a window can be created to offer additional access to the cement mantle.

In the event the surgeon has required an osteotomy or window, cerclage wires, cables or suture will be needed and when the bone is potentially compromised, allograft bone graft struts (tibial shaft) are used for additional support. Care is needed when passing cerclage wires to avoid injury to the radial nerve which is adjacent to the deltoid insertion.

If infection is suspected or confirmed an ALBC spacer is placed. When single stage revision is planned both cemented and uncemented stem options are available. Cement placed around the humeral stem has been suggested to decrease infection incidence.

Revision of cemented humeral stems is a continued challenge in revision shoulder surgery. Newer systems and reverse total shoulder options have improved the surgeon's ability to achieve good outcomes when revising prior shoulder arthroplasty.

Since its inception, knee arthroplasty has struggled to balance the requirements of relieving pain and restoring function in a durable way. Although highly successful in improving symptoms as measured by traditional outcome measures and achieving longevity, numerous studies have shown the problems that exist, even with well-implanted components of modern design. Some patients complain of ongoing functional limitation, discomfort, and pain. There are still many challenges in knee arthroplasty. We have a young population that is increasingly active that requires these procedures and yet they are living to a ripe old age and remaining ambulant into their 80s and 90s. We have focussed for the last decade on improving function and satisfaction in knee arthroplasty but we should not forget the fact that the highest failure rate is seen in our young patients and that we really do need a durable solution that will last several decades. There are several tensions that need to be considered. Should we resurface the knee early, particularly now that we have access to navigation and robotics and can effectively customise the implants to the patient's anatomy and their gait pattern? This would allow good function at a young age. Or should we wait as long as possible and risk losing some function for the sake of preserving the first arthroplasty for the lifetime of the patient?

Should we for example accept alignment paradigms that we know give us longevity or should we go with alternative kinematic or anatomical alignment techniques that may well give us better function but could compromise long-term fixation? Both registries and the long-term studies available suggest that we can expect good survivorship into the second decade for older patients and for some into the third decade, but data beyond that is sparse and is not available with contemporaneous implants. Changing the polyethylene in the knee may prove to be successful but may yet be nowhere near as beneficial as it has been in the hip. There has also been all too little work to consider the changing physiology of the bone. Will the increasing trend for cementless implants lead to longer lasting osseointegration or will it lead to periprosthetic fractures through areas of stress shielding? We have been spared somewhat thus far in the knee the issue of local metal ion effects and systemic issues that we have seen in the hip. If our implants last longer and are treated more brutally by an active patient population, we may yet see more problems. At the same time, we have to continue evolving our technologies and yet be cost effective and affordable. Our focus on operative efficiency, early discharge, rapid recovery and a return to full function must not compromise our goals and plans for implant longevity. The next stage will no doubt involve close co-operation between surgeons, engineers and industry partners to identify individual surgical targets, select an appropriate prosthesis to minimise soft-tissue strain and develop a reproducible method of achieving accurate implantation. However, in seeking to solve the problems seen in a proportion of arthroplasty patients, the achievements of ‘traditional’ total knee arthroplasty should not be overlooked. The results achieved by such methods in all three domains: pain relief, functional restoration and longevity, should act as baseline measures for newer techniques and designs. Improvements in any one domain should not be at the expense of another. An ideal outcome can only be achieved by an appropriately trained surgeon selecting the optimal prosthesis to implant in the correct position in the well-selected patient.

Until recently, research has failed to show a difference between posterior-stabilised (PS) and cruciate-retaining (CR) designs in total knee arthroplasty (TKA). This classic debate has been given pause over the past decade due to futile efforts to prove one design superior over the other. Recently, anterior-lipped and more conforming CR bearings have emerged to substitute for the PCL, if absent, damaged or resected, and obviate the need for the archaic cam-post mechanism of a traditional PS design. Advantages of avoiding a PS TKA include decreasing the risk of femoral condylar fracture that may occur via the box cut, as well as decreasing operative time by removing that step in the procedure. Avoiding a post-cam mechanism also removes the articulation that is a source of wear, post deformation, breakage, or dislocation. Patella clunk is also associated solely with PS designs.

Anterior lipped inserts in PCL-deficient TKAs have demonstrated similar functional outcomes compared to PS knees. A prospective randomised controlled trial of 28 patients undergoing bilateral TKAs had a PS bearing in one knee and a contralateral CS insert with the PCL excised and reported no functional outcome difference at 5-year follow up. Scott and co-authors compared 56 PS TKAs to 55 TKAs with anterior-lipped inserts in a randomised, prospective study and found no functional outcome differences at minimum two-year follow up, with tourniquet times significantly longer in the PS group. In a recent report, 43 anterior-lipped compared to 39 matched PS TKAs had equivalent function scores at minimum 1-year follow-up. Ultra-congruent bearings provide inherent stability in TKA and two studies have reported identical functional outcomes compared to PS TKAs.

Equivalent functional outcomes in multiple studies comparing CR-type bearings and PS TKAs, combined with the potential deleterious outcomes associated with PS designs, preclude the need for PS TKA designs in the modern healthcare environment. Hence, PS TKA designs are truly “vestigial organs” and should be relegated to historical interest.

The debate regarding the superiority of retaining (CR) or substituting (PS) for the PCL in total knee arthroplasty (TKA) has continued for a generation, without a clear consensus as to which is superior. That debate continues today.

Many studies on this subject have been published, including recent meta-analyses, which demonstrate similar outcomes between CR and PS TKA. Pain scores and functional outcomes appear quite similar between the groups. One outcome measure that appears superior in PS knees, although by a small margin, is in final range of motion, with higher final flexion observed in PS knees. Another study demonstrated superior extensor mechanism efficiency in PS designs compared to CR.

The primary explanation for improved motion is the rollback induced by the cam and post mechanism of the PS knee. By insuring rollback of the femur on the tibia, the chance of impingement between the back of the femur and polyethylene is diminished. This cam and post induced rollback has been shown to be more consistent with native knee kinematics compared to the CR knee, which can be subject to “paradoxical motion”, the forward sliding of the femur on the tibia during knee flexion.

The clear downsides of the PS knee include an increased rate of patellar clunk and crepitus, intercondylar femur fracture, post failure, and bone loss due to the box cut. The gaps must be carefully balanced to prevent a loose flexion gap which can allow the cam to “jump the post”. With improved implant design and materials, each of these complications has been reduced, but surgeons need to recognise these possibilities to reduce the incidence and identify them when they occur. Improvements in the trochlear geometry have significantly reduced the patellofemoral complications, a significant historical problem for patients with PS devices.

Indications for using a PS knee include patients with a prior patellectomy, patients with PCL deficiency, or those with a higher risk of late PCL rupture such as patients with poor neuromuscular control or rheumatoid arthritis, although there are reports successful use of CR TKA in rheumatoid arthritis.

Over the past 30 years, cemented, cementless, and hybrid fixation options have been utilised with various total knee arthroplasty (TKA) implant systems. While cemented components are widely used and considered the most reliable method of fixation, historical results may not be applicable to contemporary patients, who are increasingly younger than 65 years of age. Moreover, the literature is not definitive on which method of TKA fixation obtains the best clinical, functional, and radiographic results. A recent Cochrane meta-analysis on roentgen stereophotogrammetric analysis (RSA) included five randomised clinical trials (RCTs) in 297 participants. The authors observed that cemented fixation of tibial components demonstrated smaller displacement in relation to cementless fixation. However, the risk of future aseptic loosening with uncemented fixation was approximately half that of cemented fixation (risk ratio = 0.47, 95% CI 0.24 to 0.92) with a 16% absolute risk difference between groups. Almost all included studies recorded functional measures of Knee Society and Hospital for Special Surgery knee scores, but the authors of each study found no significant difference between the groups. Recently, highly porous metals have become an attractive fixation option in TKA due to their biomechanical properties. In a large RCT of 397 patients, Pulido et al found that uncemented highly porous metal tibias provided comparably durable fixation and reliable pain relief and restoration of function when compared with traditional cemented modular tibias. While longer-term studies are needed, cementless TKAs may be a durable and reliable alternative with highly porous metals, particularly in younger patients.

Total knee arthroplasty (TKA) is reliable, durable, and reproducible in relieving pain and improving function in patients with arthritis of the knee joint. Cemented fixation is the gold standard with low rates of loosening and excellent survivorship in several large clinical series and joint registries. While cementless knee designs have been available for the past 3 decades, changing patient demographics (i.e. younger patients), improved implant designs and materials, and a shift towards TKA procedures being performed in ambulatory surgery centers has rekindled the debate of the role of cementless knee implants in TKA.

The drive towards achieving biologic implant fixation in TKA is also driven by the successful transition from cemented hip implants to uncemented THA. However, new technologies and new techniques must be adopted as a result of an unmet need, significant improvement, and/or clinical advantage. Thus, the questions remain: 1) Why switch; and 2) Is cementless TKA more reliable, durable, or reproducible compared to cemented TKA?

There are several advantages to using cement during TKA. First, the technique can be universally applied to all cases without exception and without concerns for bone health or structure. Second, cement can mask imprecisions in bone cuts and is a remarkably durable grout. Third, cement allows for antibiotic delivery at the time surrounding surgery which has been shown in some instances to reduce the risk of subsequent infection. Finally, cement fixation has provided successful and durable fixation across various types knee designs, surface finishes, and articulations.

On the other hand, cementless knee implants have had an inconsistent track record throughout history. While some have fared very well, others have exhibited early failures and high revision rates. Behery et al. reported on a series of 70 consecutive cases of cementless TKA matched with 70 cemented TKA cases based on implant design and demographics and found that cementless TKA was associated with a greater risk of aseptic loosening and revision surgery at 5 years follow up. Finally, to date, there has not been a randomised controlled clinical trial demonstrating superiority of cementless fixation compared to cemented fixation in TKA.

Improvements in materials and designs have definitely made cementless TKA designs viable. However, concerns with added cost, reproducibility, and durability remain. Cement fixation has withstood the test of time and is not the main cause of TKA failure. Therefore, until there is significant data showing that cementless TKA is more durable, reliable, and reproducible compared to cemented TKA, the widespread use of these implants cannot be recommended.

Restoring the overall mechanical alignment to neutral has been the gold standard since the 1970s and remains the current standard of knee arthroplasty today. Recently, there has been renewed interest in alternative alignment goals that place implants in a more “physiologic” position with the hope of improving clinical outcomes. Anywhere from 10 – 20% of patients are dissatisfied after knee replacement surgery and while the cause is multifactorial, some believe that it is related to changing native alignment and an oblique joint line (the concept of constitutional varus) to a single target of mechanical neutral alignment. In addition, recent studies have challenged the long held belief that total knee placed outside the classic “safe zone” of +/− 3 degrees increases the risk of mechanical failure which theoretically supports investigating alternative, more patient specific, alignment targets.

From a biomechanical, implant retrieval, and clinical outcomes perspective, mechanical alignment should remain the gold standard for TKA. Varus tibias regardless of overall alignment pattern show increased polyethylene wear and varus loading increases the risk of posteromedial collapse. While recently questioned, the evidence states that alignment does matter. When you combine contemporary knee designs placed in varus with an overweight population (which is the majority of TKA patients) the failure rate increases exponentially when compared to neutral alignment. A recent meta-analysis on mechanical alignment and survivorship clearly demonstrated reduced survivorship for varus-aligned total knees.

The only way to justify the biomechanical risks associated with placing components in an alternative alignment target is a significant clinical outcome benefit but the evidence is lacking. A randomised control trial comparing mechanical alignment (MA) and kinematic alignment (KA) found a significant improvement in clinical outcomes and knee function in KA patients at 2 year follow-up. In contrast, Young et al. recently published a randomised control trial comparing PSI KA and computer assisted mechanical TKA and found no difference in any clinical outcome measure. Why were the clinical outcomes scores in the MA patients so different: One potential explanation is that different surgical techniques were used. In the Dosset study, the femur was cut at 5 degrees valgus in all patients and femoral component rotation was always set at 3 degrees externally rotated to the posterior condylar axis. We know from several studies that this method leads to inaccuracies in both coronal plane and axial plane in some patients. Young et al. used computer assisted navigation to align his distal femur cut with the mechanical axis and adjusted femoral component rotation to the transepicondylar axis. The results suggest that a well performed mechanical aligned total knee replacement has excellent clinical performance equal to that of kinematic alignment without any of the long term risks of implant failure. Most contemporary TKA implants are designed to be loaded perpendicular to the polyethylene surface and placing them in shear without extensive biomechanical testing to support this alignment target may put patients at long term risk for an unproven benefit. Have we not learned our lesson?

There has been a renewed interest in the importance of achievement of a neutral, mechanical alignment in total knee arthroplasty (TKA). The purpose of this presentation is to argue the merits behind questioning a neutral, mechanical alignment following TKA, and why the concepts of “constitutional varus” and “kinematic alignment” deserve further investigation.

The impact of alignment on outcomes following TKA has been questioned for a number of reasons. First, recent investigations have highlighted that approximately 20% of patients are not satisfied with their outcome following TKA. Second, recent studies have shown that achievement of a mechanical axis within 3 degrees of neutral does not necessarily improve survivorship or clinical outcomes. Third, as patients requiring TKA have a wide array of morphologies and alignment, targeting the exact same alignment for each patient has been questioned. Lastly, despite the advent of new implant designs with proposed benefits of improved kinematics, few studies have shown a clinical improvement with their use.

The concept of “constitutional varus” has suggested that restoration of a neutral, mechanical alignment may not be desirable and unnatural as 32% of men and 17% of women have a natural mechanical alignment of greater than 3 degrees at skeletal maturity. The “kinematic alignment” technique focuses on restoration of the joint line of the distal femur, posterior femur, and tibia to those of the non-arthritic, native knee. The kinematic alignment technique has shown promising results. However, while these concepts have merit, questions still remain regarding the optimal alignment target for each, individual patient.

Over the past fifteen years, the average length of stay for total hip (THA) and total knee arthroplasty (TKA) has gradually decreased from several days to overnight. The most logical and safest next step is outpatient arthroplasty. Through the era of so-called minimally invasive surgery, perhaps the most intriguing advancements are not related to the surgery itself, but instead the areas of rapid recovery techniques and peri-operative protocols. Rapid recovery techniques and peri-operative protocols have been refined to allow for same-day discharge with improved outcomes. In addition to Rapid Recovery techniques for the clinical care of the outpatient, one critical component to same-day total knee arthroplasty is the efficient performance and simplicity of the procedure itself. Simplified instrumentation and elimination of modularity can provide that efficiency and simplicity.

All polyethylene tibial components have been mostly supplanted by modular metal-backed designs in recent years. However, mounting evidence suggests that survivorship of TKA with an all-poly tibia is superior to TKA with metal-backed, modular designs in all age groups except younger than 55, in which survival is equal to a modular design. Furthermore, this survival advantage was unaffected by obesity. Combining these excellent clinical results with the efficiency of a non-modular component can add to the efficiency and simplicity of the surgical technique. Therefore, in outpatient total knee arthroplasty, the all-poly tibia truly represents the less is more mentality.

Venous thromboembolic (VTE) events including deep vein thrombosis (DVT) and pulmonary embolism (PE) remain a significant concern following total joint arthroplasty. The American Academy of Orthopaedic Surgeons (AAOS) guidelines for VTE prophylaxis have focused on the safety of prophylactic regimens, with the primary endpoint being prevention of symptomatic events while avoiding the risks of hematoma, infection, and re-operation associated with aggressive anticoagulation. In 2007, the AAOS clinical practice guideline recommended “risk stratification” of patients for VTE events and bleeding. Unfortunately, there remains limited evidence as to specific factors that should be used during pre-operative risk stratification.

A prior investigation has demonstrated the effectiveness of using a history of VTE events, active cancer, and hypercoagulable state (i.e. Factor V Leiden) as criteria for high-risk patients undergoing total joint arthroplasty. In addition, large national database systems have been used to identify risk factors for VTE events. Unfortunately, these investigations emphasise different risk factors and their importance in increasing the risk of VTE events. Thus, criteria to be used for risk stratification of patients undergoing total joint arthroplasty remain unclear. What remains clear is that even in healthy patients who are aggressively anticoagulated, a VTE event can still occur.

Bilateral one stage total knee replacement (TKR) has a number of advantages. There is one operative procedure and anesthetic and overall recovery time is significantly reduced. It is a more cost-effective procedure in that acute hospital stay is less and although rehabilitation time is greater in the short term, overall it is less. Additionally, if there is a bilateral flexion contracture present there is an inevitable loss of extension if a single knee is operated upon as this knee will assume the position of the unoperated knee. Patients greatly prefer having both knees corrected at one operative setting rather than having to have the inconvenience and pain associated with a second operative procedure at three to six months after the first one.

There are potential disadvantages to a one stage procedure. One concern has been that there is more peri-operative morbidity associated with one stage bilateral total knee replacement. In a review of 501 patients undergoing bilateral one stage total knee replacement at the Hospital for Special Surgery (HSS) there were no peri-operative deaths, myocardial infarctions or cerebrovascular accidents. There were arrhythmias present in 5% of patients. Fat emboli were present in 3% and 2 patients (0.4%) had pulmonary emboli. The average transfusion requirement was 2.6 units and allogeneic blood was required in 42%. There were 2 deep infections, 3 hematomas and 5 patients with delayed wound healing There was an increased incidence of major complications in patients with ASA classification 3 and with increasing age over 70 years.

New data indicates peri-operative administration of hydrocortisone may mitigate lung injury as demonstrated by reduction in cytokine and desmosine levels in a randomised trial. There was also a trend toward less need for narcotic medication and better range of motion in the steroid treated group

Patient selection is important and all patients are screened pre-operatively by an internist and anesthesiologist. In over 3000 bilateral TKRs at HSS infection rate and mortality were lower than in the unilateral total knee replacement patients. Much of this is due to patient selection criteria. All patients underwent the procedure with epidural anesthesia with post-operative epidural PCA for 48 hours. All patients are discharged on warfarin and spend the operative night in the recovery room. The procedure has acceptable morbidity and great advantage in properly selected patients.

The entirety of the patient experience after contemporary total knee and total hip replacements in 2016 is markedly different from that encountered by patients just a decade ago. Ten years ago most patients were treated in a traditional sick-patient model of care and because they were assumed to require substantial hospital intervention, many cumbersome and costly interventions (e.g. indwelling urinary catheters, patient-controlled-analgesic pumps, autologous blood transfusion, continuous passive motion machines) were a routine part of the early post-operative experience. Today the paradigm has shifted to a well-patient model with a working assumption that once a patient has been medically optimised for surgery then the intervention itself, hip or knee replacement, will not typically create a sick-patient. Instead it is expected that most patients can be treated safely and more effectively with less intensive hospital intervention. While as orthopaedic surgeons we are enamored with the latest surgical techniques or interesting technologies most busy surgeons recognise that advances in peri-operative pain management, blood management, and early-mobilisation therapy protocols account for the greatest share of improvements in patient experience over the past decade.

One can think pragmatically to get ahead and stay ahead of 3 predictable physiologic disturbances that adversely impact rapid recovery after knee and hip replacement: fluid/blood loss; pain; and nausea. The modern orthopaedic surgeon and his/her care team needs a simple strategy to pro-actively, not reflexively, manage each of those 3 predictable impediments to early recovery. Those surgical teams that routinely get ahead and stay ahead in each of those areas will routinely witness faster recovery, lower costs and greater patient satisfaction and that is clearly a win for patient and surgeon alike.

Effective pain management improves patient satisfaction, decreases hospital stay, and facilitates discharge to home. Today's emphasis is on a multi-modal strategy that minimises the use of opioids. Most protocols use pre-operative medications including an NSAID, acetaminophen, an oral opioid and some include gabapentin. Regional anesthesia is typically preferred over general. Both peripheral nerve blocks and periarticular local anesthetic cocktail injections have proved as effective adjuncts in decreasing early post-operative pain. Post-operative oral medications delivered on a schedule, not just as needed, often include acetaminophen, an NSAID and some included gabapentin. Oral and parenteral opioids are reserved for breakthrough pain.

Knee replacement is a proven and reproducible procedure to alleviate pain, re-establish alignment and restore function. However, the quality and completeness to which these goals are achieved is variable. The idea of restoring function by reproducing condylar anatomy and asymmetry has been gaining favor As knee replacements have evolved, surgeons have created a set of principles for reconstruction, such as using the femoral transepicondylar axis (TEA) in order to place the joint line of the symmetric femoral component parallel to the TEA, and this has been shown to improve kinematics. However, this bony landmark is really a single plane surrogate for 3-dimensional medial and lateral femoral condylar geometry, and a difference has been shown to exist between the natural flexion-extension arc and the TEA. The TEA works well as a surrogate, but the idea of potentially replicating normal motion by reproducing the actual condylar geometry and its involved, individual asymmetry has great appeal.

Great variability in knee anatomy can be found among various populations, sizes, and genders. Each implant company creates their specific condylar geometry, or “so called” J curves, based on a set of averages measured in a given population. These condylar geometries have traditionally been symmetric, with the individualised spatial placement of the (symmetric) curves achieved through femoral component sizing, angulation, and rotation performed at the time of surgery. There is an inherent compromise in trying to achieve accurate, individual medial and lateral condylar geometry reproduction, while also replicating size and avoiding component overhang with a set implant geometry and limited implant sizes. Even with patient-specific instrumentation using standard over-the-counter implants, the surgeon must input his/her desired endpoints for bone resection, femoral rotation, and sizing as guidelines for compromise. When all is done, and soft tissue imbalance exists, soft tissue release is the final, common compromise.

The custom, individually made knee design goals include reproducible mechanical alignment, patient-specific fit and positioning, restoration of articular condylar geometry, and thereby, more normal kinematics. A CT scan allows capture of three-dimensional anatomical bony details of the knee. The individual J curves are first noted and corrected for deformity, after which they are anatomically reproduced using a Computer-Aided Design (CAD) file of the bones in order to maximally cover the bony surfaces and concomitantly avoid implant overhang. No options for modifications are offered to the surgeon, as the goal is anatomic restoration.

Given these ideals, to what extent are patients improved? The concept of reproducing bony anatomy is based on the pretext that form will dictate function, such that normal-leaning anatomy will tend towards normal-leaning kinematics. Therefore, we seek to evaluate knee function based on objective assessments of movement or kinematics.

The use of custom knee technology to more closely reproduce an individual patient's anatomy holds great promise in improving the quality and reproducibility of post-operative function. Compromises of fit and rotation are minimised, and implant overhang is potentially eliminated as a source of pain. Early results have shown objective improvements in clinical outcomes. Admittedly, this technology is limited to those patients with mild to moderate deformity at this time, since options like constraint and stems are not available. Yet these are the patients who can most clearly benefit from a higher functional state after reconstruction. Time will reveal if this potential can become a reproducible reality.

Extra-articular deformity may be present in patients requiring TKA. Underlying causes include trauma, metabolic bone disease, congenital deformity, or prior osteotomy. Patients with intra-articular deformity have a combination of intra-articular bone loss and concomitant ligament contraction which can be managed in the standard fashion. In these cases establishing appropriate limb alignment and management of bone loss coincide well with the standard ligament balancing employed to provide a stable knee.

However, if extra-articular deformity is not corrected extra-articularly, it must be corrected by a compensatory distal femoral or proximal tibial resection to reproduce appropriate limb alignment. Complex instabilities may result from this type of wedge resection because it occurs between the proximal and distal attachments of the collateral ligaments and so produces asymmetrical ligament length alterations.

Femoral compensatory wedge resection for extra-articular deformity produces extension instability without affecting the flexion gap and so femoral deformities are POTENTIALLY more difficult to correct than tibial deformities where the compensatory tibial cut influences flexion AND extension equally. Lack of access to the intramedullary canal (as well as increased complexity of producing appropriately placed bone cuts) may be managed with computer guidance or patient specific instruments.

The closer a deformity is to the knee, the greater its importance and the effect on the surgical correction. This is a directly proportional relationship, so that as the apex of the deformity moves from juxta-articular to more distant, the amount of corrective wedge needed to re-align the limb decreases proportionally.

Rotatory deformities most commonly effect extensor mechanism tracking. The effect is similar to any other deformity in that proximity to the knee and increases the likelihood that it will have a significant local effect. In general, these deformities may be clinically, and radiographically more subtle and so must be searched for. They should be managed by restoring normal rotational parameters of the bone or by appropriate compensation of component rotation relative to the bone.

As the need for prosthetic constraint increases due to ligament imbalance or deficiency, intramedullary stems may be required. Their use may be compromised by the presence of the deformity. The younger the patient and the more severe the deformity the more likely I am to treat the deformity by correction at the site of the deformity rather than compensating with abnormal bone resections. The older the patient and the milder the deformity (or the amount of correction required) the more intra-articular correction +/− increased TKA constraint is feasible.

Fifteen-year survivorship studies demonstrate that total knee replacements have excellent survivorship, with reports of 85% to 97%. However, excellent survivorship does not equate to excellent patient reported outcomes. Noble et al. reported that 14% of their patients were dissatisfied with their outcome with more than half expressing problems with routine activities of daily living. There is also a difference in the patient's subjective assessment of outcome and the surgeon's objective assessment. Dickstein et al. reported that a third of total knee patients were dissatisfied, even though the surgeons felt that their results were excellent. Most of the patients who report lower outcome scores due so because their expectations are not being fulfilled by the total knee replacement surgery.

Perhaps this dissatisfaction is a result of subtle soft tissue imbalance that we have difficulty in assessing intra-operatively and post-operatively. 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 and accelerometers, used in the knee with the medial retinaculum closed, can provide dynamic, intra-operative feedback regarding knee quantitative compartment pressures and component tracking. After all bone cuts are made using the surgeon's preferred techniques, trial components with the sensored tibial trial are inserted and the knee is taken through a passive range of motion. After visualizing the resultant compartment pressures and tracking data on a graphical interface, the surgeon can decide whether to perform a soft tissue balance or minor bone recuts. If soft tissue balancing is chosen, pressure data can indicate where to perform the release and allow the surgeon to assess the pressure changes as titrated soft tissue releases are performed.

A multi-center study using smart trials has demonstrated dramatically better outcomes out to three years.

This session will present a series of challenging and complex primary and revision cases to a panel of internationally respected knee arthroplasty experts.

The primary cases will include challenges such as patient selection and setting expectations, exposure, alignment correction and balancing difficulties. In the revision knee arthroplasty scenarios issues such as bone stock loss, fixation challenges, instability, and infection management 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.

Most total knee prostheses are designed to have limited congruence between the femoral and tibial components to reduce constraint, based on the widely accepted principle that “constraint causes loosening”.

Studies of the normal knee, however, indicate that stability under axial load occurs mostly by the geometric conformity of the surfaces. When moving in the plane of flexion-extension, the ligaments contribute little to stability because the ligaments are in the “toe-region” of their force-displacement curve. When an “out-of-plane” load is applied (i.e., load outside the plane of flexion-extension), ligaments are “recruited” for stability by being stressed into the elastic portion of the curve to resist the load.

For the traditional total knee prosthesis, because of the lack of geometric congruity, the ligaments must provide all stability by being “balanced”, i.e. tensioned into the elastic portion of the force-displacement curve. Further, they must remain in that tensioned state indefinitely, with no stretching or migration of the implant.

The medial pivot knee design has a fully conforming medial “ball-in-socket” articulation that provides stability to the knee through the geometric conformity. Ligaments need not be tensioned into the elastic region of the force-displacement curve but can be left in the toe-region to be recruited for out-of-plane loads.

Clinical follow-up results in patients with a medial pivot prosthesis indicate that, based on Knee Society and WOMAC scores, patients report greater than 90% satisfaction with pain and function. Further, the most satisfied patients are those who, during physical examination, display medial and lateral opening that might be classified as “mid-flexion instability” for prostheses that depend on ligament tensioning for stability.

Cementless fixation in TKA has been inconsistently adopted since its early use but is increasing due to a number of factors, predominantly related to a demand for improved survivorship in younger patients. Modern biomaterials have demonstrated optimal bone ingrowth and have also contributed to a renewed confidence by surgeons to utilise cementless fixation in TKA. With a modern design and appropriate surgical technique, optimal mechanical stability of new designs have been demonstrated and can build upon the excellent long-term outcomes that have rivaled traditional cemented TKA. Paramount to obtaining successful long-term osseointegration and clinical survivorship with cementless fixation is an awareness of the past failure mechanisms to improve implant modern implant design, and should also guide meticulous surgical technique.

A robust implant design with optimal surgical technique is critical to success when employing cementless fixation in TKA. The tried and true principles of sufficient mechanical stability to minimise micromotion of an osteoconductive implant surface with intimate contact against viable bone are essential to allow osseointegration and long-term survivorship. The surgical techniques and tips for “getting it right” include: 1.) Meticulous planar cuts - Prevention of saw blade deviation (particularly anterior femoral cortex and sclerotic medial tibial plateau), Appropriate tolerances in cutting guides (particularly 4-in-1 femoral cutting guide), Appropriate interference fit for tibial keel/stem, patella planar cut, Perfect planar cut on tibial surface confirmed with “4-corner test”. 2.) Implantation of components to maximise mechanical stability - Intimate implant contact with bone (minimizing gaps), Consider bone slurry to minimise gaps, Prevention of femoral component flexion with impaction, Ensure parallel position of tibial baseplate with tibial cut surface during impaction, Peripheral fixation on tibial baseplate, either screws or pegs, to provide supplemental fixation and stability in titanium tray designs.

Robotic arm-assisted total knee replacement is performed as a semi-active system in which haptic guidance is used to precisely position and align components. This is based on pre-operative planning based on CT imaging and can be modified as needed throughout the procedure. This technology, as shown with unicompartmental arthroplasty, is more accurate than conventional and even computer navigated instrumentation and will decrease variability. The knee can be planned to a neutral mechanical alignment. Intra-operatively, the computer will demonstrate compartment gap measurements to assist with soft tissue balancing.

Alternatively, limb and component alignment can be accurately adjusted several degrees off the neutral axis to balance the knee and avoid or minimise soft tissue releases. This allows a more constitutional alignment within the alignment parameters accepted by the surgeon. This technique was utilised commonly in the first 60 robotic total knee replacements performed.

We will now have the ability to collect accurate component positioning, alignment, and soft tissue balance data that can be correlated to outcomes of total knee replacements.

Alignment of total joint replacement in the valgus knee can be done readily with intramedullary alignment and hand-held instruments. Intramedullary alignment instruments usually are used for the femoral resection. The distal femoral surfaces are resected at a valgus angle of 5 degrees. A medialised entry point is advised because the distal femur curves toward valgus in the valgus knee, and the distal surface of the medial femoral condyle is used as reference for distal femoral resection. In the valgus knee, the anteroposterior axis is especially important as a reliable landmark for rotational alignment of the femoral surface cuts because the posterior femoral condyles are in valgus malalignment, and are unreliable for alignment. Rotational alignment of the distal femoral cutting guide is adjusted to resect the anterior and posterior surfaces perpendicular to the anteroposterior axis of the femur. In the valgus knee this almost always results in much greater resection from the medial than from the lateral condyle. Intramedullary alignment instruments are used to resect the proximal tibial surface perpendicular to its long axis. Like the femoral resection, resection of the proximal tibial surface is based on the height of the intact medial bone surface.

After correction of the deformity, ligament adjustment is almost always necessary in the valgus knee. Stability is assessed first in flexion by holding the knee at 90 degrees and maximally internally rotating the extremity to stress the medial side of the knee, then maximally externally rotating the extremity to evaluate the lateral side of the knee. Medial opening greater than 4mm, and lateral opening greater than 5mm, is considered abnormally lax, and a very tight lateral side that does not open at all with varus stress is considered to be abnormally tight. Stability is assessed in full extension by applying varus and valgus stress to the knees. Medial opening greater than 2mm is considered to be abnormally lax, and a very tight lateral side that does not open at all with varus stress is considered to be too tight.

Release of tight structures should be done in a conservative manner. In some cases, direct release from bone attachment is best (popliteus tendon); in others, release with pie-crusting technique is safe and effective. In knees that are too tight laterally in flexion, but not in extension, the LCL is released in continuity with the periosteum and synovial attachments to the bone. When this lateral tightness is associated with internal rotational contracture, the popliteus tendon attachment to the femur is also released. The iliotibial band and lateral posterior capsule should not be released in this situation because they provide lateral stability only in extension.

The only structures that provide passive stability in flexion are the LCL and the popliteus tendon complex, so knees that are tight laterally in flexion and extension have popliteus tendon or LCL release (or both). Stability is tested after adjusting tibial thickness to restore ligament tightness on the lateral side of the knee. Additional releases are done only as necessary to achieve ligament balance. Any remaining lateral ligament tightness usually occurs in the extended position only, and is addressed by releasing the iliotibial band first, then the lateral posterior capsule, if needed. The iliotibial band is approached subcutaneously and released extrasynovially, leaving its proximal and distal ends attached to the synovial membrane. In knees initially too tight laterally in extension, but not in flexion, the LCL and popliteus tendon are left intact, and the iliotibial band is released. If this does not loosen the knee enough laterally, the lateral posterior capsule is released. The LCL and popliteus tendon rarely, if ever, are released in this type of knee.

Finally, the tibial component thickness is adjusted to achieve proper balance between the medial and lateral sides of the knee. Anteroposterior stability and femoral rollback are assessed, and posterior cruciate substitution is done, if necessary, to achieve acceptable posterior stability.

Controversy remains regarding the optimal treatment for iatrogenic injury to the medial collateral ligament (MCL) during primary total knee arthroplasty (TKA). Some authors have recommended converting to a prosthesis that provides varus/valgus constraint while others have recommended primary repair. In this study we report the results of a 45 patients who sustained intra-operative MCL injuries during primary TKA that were treated with primary repair.

Of 3922 consecutive primary TKA there were 48 (1.2%) intra-operative MCL lacerations or avulsions. One patient was lost and one died before 24-month follow-up. All but one patient underwent primary repair with placement of components without varus/valgus constraint. This left 45 knees with a mean follow up of 89 months (range, 24 – 214 months). The mean HSS knee scores increased from 47 to 85 points (p<0.001). No patients had subjective complaints of instability. No patients had excessive varus/valgus laxity when tested in full extension and 30 degrees of flexion. The range of motion at the time of final follow-up averaged 110 degrees (range, 85 – 130 degrees). Five knees required treatment for stiffness with 4 knees undergoing manipulation under anesthesia and 1 knee undergoing open lysis of adhesions with polyethylene articular surface exchange. Two knees underwent revision for aseptic loosening of the tibial component. In the three knees that underwent open revision, the MCL was noted to be in continuity and without laxity.

Primary repair with 6 weeks of post-operative hinged bracing after iatrogenic injury to the MCL during primary TKA was successful at preventing instability although stiffness was seen in approximately 10% of patients. The increased morbidity associated with implantation of a semi-constrained or constrained implant may be unwarranted in this situation.

Wound closure is not often an area that is discussed by orthopaedic surgeons. We commonly attend meetings and talks related to different types of implants and surgical technique but in reality the wound and how we close it maybe one of the most important aspects of a surgical procedure. The avoidance of wound complications such as unplanned clinic visits, readmissions, reoperations and deep infections are very important as we move into a world of bundled payments and public reporting of complications. Not to mention the poor results for the patients when wound complications occur. Often there is little thought about how wound closure and surgical dressings could affect surgical site healing. We all have a common belief that blisters, drainage and surgical site infections are rare. In the literature it has been shown that the method of wound closure can influence skin and soft tissue perfusion. Which closure techniques can achieve physiologic blood flow, which may improve wound healing? This talk will cover topics related to reducing the dead space, avoidance of hematoma formation and what the literature says regarding different types of wound closure materials.

The incidence of major complications following total joint arthroplasty is low, however, surgeons often continue to see patients regularly to monitor outcomes and the performance of the implant. The purpose of this study was to assess the feasibility, effectiveness and cost-effectiveness of a web-based follow-up compared to in-person assessment following primary total hip or total knee arthroplasty. We also determined patient satisfaction and preference for follow-up method.

Patients who were at least 12 months post-operative were randomised to complete either a web-based follow-up or to have their appointment at the clinic, as usual. We excluded patients who had revision surgery, osteolysis, or identified radiographic issues. We report the frequency of web-based patients who had an issue missed by using the web-based follow-up. We recorded travel costs and time associated with each follow-up, and any health care resource use for one year following the assessment. We conducted a cost analysis from the health-care payer (Ontario Ministry of Health and Long-Term Care) and societal perspectives. All costs are presented in 2012 Canadian dollars. We used descriptive statistics to summarise the satisfaction and preference results and compared satisfaction between groups using Pearson's chi-square test.

Two-hundred-twenty-nine patients completed the study (111 usual-care, 118 web-based), with a mean age of 69 years (range, 38 – 86 years). There were no patients who had an issue missed by the web-based follow-up. The cost for the web-based assessment was significantly lower from both the societal perspective (mean difference, −$64; 95% confidence interval, −$79 to −$48; p < 0.01) and the health-care payer perspective (mean difference, −$27; 95% CI, −$29 to −$25; p < 0.01). Ninety-one patients (82.0%) in the usual-care group indicated that they were either extremely or very satisfied with the follow-up process compared with 90 patients (75.6%) in the web-based group (p < 0.01; odds ratio = 3.95; 95% CI = 1.79 to 8.76). Similarly, 92.8% of patients in the usual care group were satisfied with the care they received from their surgeon, compared to 73.9% of patients in the web-based group (p < 0.01, OR = 1.37; 95% CI = 0.73 to 2.57). Forty-four percent of patients preferred the web-based method, 36% preferred the usual method, and 16% had no preference (p = 0.01).

Web-based follow-up is a feasible, clinically effective alternative to in-person clinic assessment, with moderate to high patient satisfaction. A web-based follow-up assessment has lower mean costs per person compared to the usual method of in-person follow-up from both a societal and health-care payer perspective. The web-based assessment may introduce additional efficiency by redirecting limited outpatient resources to those awaiting first consultation, patients who have complications, or those who are further post-operative and may require a revision.

The role of metal sensitivity or allergy in causing persistent symptoms or failure and need for a revision of a total joint replacement has been the topic of debate and controversy for decades. There was renewed interest in this area with the rise of metal-on-metal hip arthroplasty and the advent of adverse local tissue reactions. This led to an increase in metal ion testing as well as metal sensitivity testing. With the decline of the use of metal-on-metal hip components, this is now mostly an issue in knee arthroplasty. It is well known that a substantial percentage of patients have persistent symptoms following knee replacement. What remains in question is whether allergy to metal or other materials such as PMMA may be a contributing factor. It is accepted that the incidence of positive skin patch tests is higher in symptomatic failed joint replacements. Nickel sensitivity is most common as a positive skin test with up to 15% of patients demonstrating this followed by chromium and cobalt. A recent review by Lachiewicz et al. concluded that there was insufficient evidence to recommend routine or widespread cutaneous or in vitro hypersensitivity testing before primary TKA, that there is no evidence-based rationale to recommend a routine metal allergy screening questionnaire, that there is only anecdotal support for Ni-free implants, and that local dermatitis should be treated with topical steroids. In another article, routine screening for metal allergy was not recommended, however, selective screening for history of sensitivity or unexplained pain or early loosening was suggested. Other experts have recommended a role for utilizing a commercially available alternative to components containing nickel or cobalt in patients thought to be hypersensitive. A recent study, however, concluded that there was no difference in complications, revisions, or reoperations among patients who tested positive with patch testing whether they were treated with standard components or nickel free components. Likewise, a consensus panel published results from the United Kingdom in which cobalt chrome implants were recommended regardless of the patients metal allergy status. Patient perception is important, however, and among patients who report multiple allergies of any kind, a higher percentage are likely to be dissatisfied with their knee replacement. Of more importance are those reporting a specific allergy to metal are substantially more likely to express some dissatisfaction with their components.

Metal allergy as a cause of chronic pain and/or early failure of joint replacement is rare if it exists at all. It is always a diagnosis of exclusion. Patients who think they are allergic are probably more likely to be more symptomatic following joint replacement. Whether or not to use a nickel free or hypoallergenic component in such patients remains an area of controversy.

The infected TKA is one of the most challenging complications of knee surgery, but spacers can make them easier to treat. An articulating spacer allows weight bearing and range of motion of the knee during rehabilitation. This spacer is made using antibiotic-impregnated bone cement applied to the tibial and femoral implant. For our purpose, 4.8g powdered tobramycin is mixed with 2g vancomycin and one batch of cement. Cement is applied early to the components, but applied late to the femur, tibia, and patella to allow molding to the defects and bone without solid adherence to bone. Patients have tailored intravenous antibiotic therapy for 6 weeks for treatment of various gram-positive and gram-negative organisms. At 10–12 weeks patients are revised to a cemented revision total knee arthroplasty using standard cementing techniques. From our experience, range of motion before reimplantation was 5 – 90 degrees. Follow-up averaged 73 months for fifty patients with 90% good to excellent results; 10% had a recurrence of infections. Use of an articulating spacer achieves soft tissue compliance, allows for ease of re-operation, reduced post-operative pain, improved function, and eradicates infection equal to standards reported in the literature.

An expert panel of orthopaedic surgeons is going to be evaluating primary and revision total hip and total knee replacements submitted by the audience. Participants will present the x-rays and clinical findings of difficult cases for which they are seeking an expert opinion from the panel. The panel will probably have conflicting opinions which will lead to an entertaining and educational session. The moderator will also provide some extremely challenging cases once again, to stimulate more controversy. This session has been very popular in the past and is fast moving, humorous and educational.

As healthcare spending continues to outpace economic growth, legislators and healthcare economists have explored many processes aimed at improving efficiency and reducing waste within a bundled care environment. Gainsharing or the general concept that organizations and their employees can work together to continually improve outcomes at reduced expenditures in exchange for a portion of the savings has been shown to be effective within the healthcare system. Although gainsharing principles may be applicable to healthcare organizations and their physician partners, specific parameters should be followed when implementing these arrangements. This talk will discuss gainsharing strategies aimed at properly aligning healthcare organizations and physicians, which, if followed, will ensure the successful implementation of gainsharing initiatives.

TKA is one of the most common orthopaedic operations performed worldwide and it is largely successful in pain relief and functional recovery. However, when pain persists post-operatively the thorough evaluation must be instituted. Extra-articular causes of knee pain include; hip pathology, lumbar spine degenerative disease or radicular symptoms, focal neuropathy, vascular disease, and chronic regional pain syndrome. Intra-articular causes of knee pain: infection, crepitation/ clunk, patella osteonecrosis, patella mal-tracking, soft tissue imbalance, malalignment, arthrofibrosis, component loosening, implant wear, ilio-tibial band irritation, and bursitis. Other causes of pain to rule out are component overhang with soft tissue irritation, recurrent hemarthrosis secondary to synovial impingement or entrapment, non-resurfaced patella, and metal sensitivity.

A careful history may reveal previous knee surgeries with delayed healing or prolonged drainage, chronology of sign and symptoms, co-morbid medical conditions, jewel or metal sensitivity.

Physical exam should help with specific signs in the operated knee. Targeted local anesthetic blocks are helpful and response to lumbar sympathetic blocks determines presence of CRPS.

Lab tests are important: ESR, CRP, WBC, aspiration with manual cell count and diff, leukocyte esterase dipstick, RA titers, metal derm patch testing, nuclear scans, CT best for rotational malalignment,, and MARS MRI.

More recently patient satisfaction as an outcome measure has shown TKA results not satisfactory in 11 – 18% of patients. A discordance of patient vs. surgeon satisfaction exists so the following factors may help improve this: correct patient selection, establishing and correlating surgeon-patient expectations, peri-operative optimisation of patient comorbidities to help avoid preventable complications, use of pre- and post-operative pathways. Satisfaction rates can best be improved by addressing the previous points with patients prior to TKA surgery.

Stiffness after total knee arthroplasty (TKA) is a common problem occurring between 5% and 30% of patients. Stiffness is defined as limited range of motion (ROM) that affects activities of daily living. A recent International Consensus on definition of stiffness of the knee graded stiffness as mild, moderate or severe (90–100, 70–89, <70, respectively) or an extension deficit (5–10, 11–20, >20). Stiffness can be secondary to an osseous, soft tissue, or prosthetic block to motion. Heterotopic bone or retained posterior osteophytes, abundant fibrotic tissue, oversized components with tight flexion or extension gaps or component malrotation can all limit knee motion. Infection should always be considered in the knee that gradually loses motion. Alternative causes include complex regional pain syndrome and Kinesiophobia that can limit motion without an underlying mechanical cause.

The evaluation of knee stiffness radiographs of the knee and cross-section imaging should be performed if component malrotation is considered. A metal suppression MRI assists in quantifying the extent of fibrosis and its location in the anterior or posterior compartment of the knee. Inflammatory markers and joint aspiration as indicated to rule out infection. Arthrofibrosis, or post-surgical fibrosis, is related to abnormal scar formation after surgery that leads to loss of motion. The cause of arthrofibrosis is multifactorial and likely related to genetic host factors. Current research is focusing on molecular signatures that may better identify patients at risk. In addition, therapeutic interventions are being studied that best prevent fibrosis and its recurrence and include the use of anti-inflammatories, corticosteroids, Colchicine, biologic medications (IL-1 inhibitors) and low-dose radiation.

Early treatment of the stiff TKA includes physical therapy and manipulation under anesthesia (MUA). MUA performed within 3 months may have the greatest increase in ROM but notable improvement can occur up to 6 months after TKA. After six months, arthroscopic or open surgery is recommended for persistent stiffness. Arthroscopic lysis of adhesions can improve ROM greater than 1 year after index TKA. Average improvement of ROM for both MUA and arthroscopic lysis of adhesions (usually in conjunction with MUA) is approximately 30 degrees. The outcome after open lysis of adhesions are reportedly poor but current adjuvant therapies may improve these clinical outcomes as this addresses the biologic, in addition to the mechanical, basis of fibrosis. Component revision performed for component malposition and stiffness has variable outcomes but a recent study reports a mean increase in ROM of 20 degrees and a modest improvement in overall knee function. The cause of post-operative stiffness after TKA is a complex interplay of the patient, surgeon, and post-operative factors. Correct diagnosis of the underlying cause of the stiff total knee is essential to optimizing treatment outcomes. More research in needed in how to best prevent and treat the biologic risk factors and pathways that contribute to post-surgical fibrosis.

A total knee replacement (TKR) with instability is one in which the supporting soft tissues have failed or are unable to function due to component size and/or position. Instability following TKR can lead to the need for surgery in 10–22% of revision cases. Patients may complain of symptoms of giving way, difficulty climbing stairs, and the sensation that their knee may buckle under stress. Physical findings may include soft-tissue tenderness in the peripatellar and pes anserine regions, recurrent joint effusions, and joint laxity. The cause of instability after TKR should be determined pre-operatively so the problem may be corrected at the time of revision.

Instability after TKR may be due to component loosening, ligament rupture/incompetence, component malposition, mismatched flexion/extension gaps, or failure to correct ligament imbalance at the time of the index procedure. A common scenario after a cruciate-retaining TKR is that of PCL rupture, thus leading to instability in flexion and excessive posterior translation of the tibia. Other scenarios leading to TKR instability are pre-operative valgus alignment with MCL stretching, resulting in the post-operative recurrence of medial instability; or excessive resection of the posterior femoral condyles from undersizing of the femoral component, leading to laxity in flexion.

The treatment of instability after TKR generally requires component revision and balancing of the flexion and extension gaps. Isolated ligament reconstruction is not successful in the setting of a prosthetic joint due to the lack of inherent joint stability. At the time of revision, the surgeon must carefully assess the flexion gap; often posterior femoral augments must be used to upsize the femoral component and tighten the flexion space relative to the extension space; for this reason, isolated polyethylene exchange is not successful for flexion instability. For instability in the varus/valgus plane, rebalancing the knee by performing ligament releases and using a more stabilizing polyethylene insert may by sufficient.

The results of revision TKR for instability has been successful in the majority of cases, decreasing the symptoms of giving way and difficulty stairclimbing. A careful assessment of the varus/valgus stability of the prosthetic knee and the flexion/extension spaces at the time of revision TKR, along with the use of augments and more stabilised articulations, is mandatory in order to achieve good results.

General Principles - All repairs should be repaired in full extension. Repairs should be immobilised in full extension for 6–12 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees. Marlex Mesh has been shown to be an excellent replacement as well as an augment for deficient soft tissue.

Acute Tibial Tuberosity Avulsion - Open repair is best accomplished with a non-absorbable heavy Krackow suture, secured distally around a screw and washer followed by 6 to 8 weeks of immobilisation. Augmentation with a semitendinosus graft or Marlex can provide additional support.

Acute Patella Tendon Rupture - End-to-end repair is standard, but re-rupture is not uncommon, so supplemental semitendinosus reconstruction is recommended. The tendon is harvested proximally, left attached distally and passed through a transverse hole in the inferior patella. The gracilis tendon can be harvested and sutured to semitendinosus for additional length, if needed.

Acute Quadriceps Tendon Rupture - These can be repaired end to end with a non-absorbable heavy Krackow suture. A superficial quadriceps fascial turndown or mesh may be a useful adjunct.

Patella Fracture - Treatment depends on the status of the patellar component and the loss of active extension. If the component remains well fixed and the patient has less than a 20-degree lag. A loose component and/or >20-degree extensor lag requires ORIF +/− component revision.

Chronic Disruptions - While standard repair techniques are possible, tissue retraction usually prevent a “tension-free” repair. If the patella remains viable and has not retracted proximally an Achilles tendon graft is appropriate while in any patellar tendon defect, mesh repair has been shown to be effective. In most chronic disruptions with loss of the patella allograft extensor mechanism reconstruction may be considered.

Drainage from the knee wound after TKA is an obvious concern for the arthroplasty surgeon. One of the inherent problems with a total knee arthroplasty is there is a focus on obtaining maximum range of motion but at the same time the wound needs to heal in a timely fashion. Consistent knee drainage after a TKA is a source of concern. The quantity and quality of drainage needs to be assessed and there are certain questions that need to be answered including: 1) Is there bloody drainage which suggests fascial dehiscence?; 2) Is the patient too active?; 3) Is the drainage in some way related to DVT prophylaxis?; 4) Is the patient obese and could the drainage be secondary to fat necrosis or seroma? and 5) Is the drainage suggestive of an infection? The work-up can include C-reactive protein and sed rate, and possibly a knee aspiration. In general, C-reactive protein >100mg/L within the first six weeks after surgery suggests the presence of an infection. The sed rate is generally not useful in the early post-operative period. In the first six weeks after surgery if the number of white cells in the aspiration is >10,000 this suggests infection especially if there are 80–90% polymorphonuclear cells.

Each day of prolonged wound drainage is noted to increase the risk of infection by 29%. Morbid obesity has been shown to be an independent risk factor for infection. Some anticoagulants (i.e. low molecular weight heparin) have been associated with increased wound drainage. In a retrospective review of 11,785 total joint arthroplasties, 2.9% of joints developed wound drainage, and of these patients, 28% required further surgery. It was noted that patients that were malnourished had a 35% failure rate with respect to controlling the drainage and preventing infection versus 5% in patients that were healthy.

The International Consensus Conference on Infection concluded that a wound that has been persistently draining for greater than 5–7 days requires surgical intervention. The available literature provides little guidance regarding the specifics of this procedure. In general, if the wound is draining or is red, rest the leg for a day or two. In some instances a bulky Jones dressing can be helpful. If the drainage persists one could consider using a negative pressure dressing (wound vac) but there is little data on efficacy after TKA. If there is persistent drainage or cellulitis, then operative intervention is probably necessary. Evaluation of CRP and a knee joint aspiration can be helpful. The decision to return to the OR should be made within the first 7 days after the surgery. At the time of the procedure one will need to decide to perform either a superficial washout versus a washout and polyethylene exchange.

Among the most critical factors to reducing the risk of infection include the use of pre-incisional antibiotics, appropriate skin preparation with clippers (as opposed to a razor for hair removal) and the use of an alcohol-based skin preparation. Host factors are also likewise critically important including obesity, diabetes, inflammatory arthritis, renal insufficiency, skin disorders and patients who are otherwise immune-compromised. If modifiable risk factors are identified, it would seem reasonable to delay elective surgery until these can be optimised.

One other factor to consider is the nutritional status of the patient. In a study of 501 consecutive revisions, we found that serological markers suggestive of malnutrition (albumin, transferrin or total lymphocyte count) were extremely common. Specifically, 53% of patients who presented for treatment of a chronic infection had at least one marker for malnutrition, compared to 33% in the group of patients undergoing revision for an aseptic reason. Malnutrition was found to be an independent risk factor for septic failure (p < 0.001 and OR 2.1). Interestingly, malnutrition was most common among patients of normal weight but was also common among obese patients (so-called “paradoxical” malnutrition). What was more disturbing, however, was that of those patients undergoing an aseptic revision, serum markers of malnutrition were associated with a 6× risk of acute post-operative infection complicating the patient's aseptic revision. We have confirmed this association using the NSQIP database where hypoalbuminemia was associated with a higher risk of infection, pneumonia and readmission.

At our center, we also have studied the use of dilute betadine at the end of the case, prior to wound closure, in an attempt to decrease the load of bacteria in the wound. In a retrospective review the prevalence of acute post-operative infection was reduced from just under 1% (18/1862) to 0.15% (1 of 688; p = 0.04). It is critical that the betadine utilised be STERILE and the dilution we use is 0.35% made by diluting 17.5cc of 10% povidone-iodine paint in 500cc of normal saline.

The infected joint arthroplasty continues to be a very challenging problem. No test has 100% diagnostic accuracy for PPI and the treating surgeon must correlate the clinical and radiographic presentation with a combination of blood tests, synovial fluid analysis, microbiological and histopathological evaluation of periprosthetic tissue and intra-operative inspection to reach a definitive diagnosis. Diagnosis should begin with a high index of suspicion for new onset of pain or symptoms in well-functioning joints. Plain radiographs may identify osteolysis or early signs of implant failure and should be promptly investigated further for PPI.

Peripheral blood ESR and CRP remain the most widely used next step for the diagnosis of PPI. Both these tests are widely available, inexpensive, and have a rapid turnaround time in laboratories. The results should be interpreted with caution due to their relative lack of specificity. The sensitivity and specificity values for CRP are approximately 88 and 74%, respectively; while that of ESR is slightly lower at 75 and 70%, respectively. The combined ESR and CRP tests are 96% sensitive for ruling out PPI but the specificity of this combination is as low as 56%. Advanced imaging modalities may be used as a part of the diagnostic algorithm. However, they require expert interpretation and are limited by availability and high costs. When available they have high sensitivity and specificity but their routine use is not recommended and indications have to be individualised in the light of clinical presentation.

In the presence of high clinical suspicion, the clinician should plan synovial fluid analysis. This provides a synovial fluid white cell count with differential cell count, specimen for culture and possibility of analyzing other synovial fluid markers. It is important to note that failed metal-on-metal hip arthroplasties can give a falsely elevated synovial fluid cell count when using automated cell counters. This can be overcome by manually counting cell numbers. Synovial fluid should be directly into blood culture bottles, and antibiotics should be withheld at least 2 weeks prior to aspiration, whenever possible. Cultures also help establish the organism, virulence and sensitivities that help plan subsequent treatment algorithm.

Periprosthetic tissue biopsy provides valuable information in microbiological diagnosis and workup of PPI. Routine use of gram staining is not recommended due to poor sensitivity. However, frozen section may have some role especially when performed by a skilled pathologist. Tissue culture remains the gold standard for diagnosis despite false-positive and false-negative results. Whenever possible multiple samples should be obtained to aid interpretation. A threshold of 2 to 3 positive specimens yielding indistinguishable microorganisms has been recommended to improve sensitivity. Acute inflammation, evidenced by neutrophilic infiltrate on fixed or frozen tissue, is suggestive of PPI and is defined as the presence of at least 5 neutrophils per high-powered field, in at least 5 separate microscopic fields.

Sonication of removed prosthetic components is used to dislodge the biofilm and the associated bacteria from the surface of the implant. The fluid surrounding the implant can be used for culture or analysis.

PCR testing: Synovial fluid aspirate, periprosthetic tissue or sonicate fluid may be subject to molecular diagnosis to amplify genetic material and improve microbiological diagnosis of PPI. This technique has shown increased sensitivity in patients who had received antibiotics within 14 days before implant removal. Results have to carefully interpreted with due consideration for possibility of false positive results.

The method of choice in the management of chronic infections is the exchange arthroplasty. The exchange arthroplasty can be performed either in a one- or in a two-stage setting, whereas the two-stage exchange arthroplasty is still considered the “gold standard” worldwide. The current literature and guidelines for PJI treatment deliver no clear evidence that a two-stage exchange procedure has a clearly higher success rate than the one-stage procedure. Since the first implantation of mixing antibiotics into bone cement in 1970s, the ENDO-Klinik followed until today in over 85% of all infected cases the one-stage exchange arthroplasty for the management of PJI. The main requirement is the known germ with known susceptibility based on microbiological diagnostics. Proper bone stock for cemented, in some cases, uncemented reconstruction, and the possibility of primary wound closure are also clear assumptions. The one-stage exchange arthroplasty delivers diverse advantages. For instance, the need for only one operation, shorter hospitalization, reduced systemic antibiotics and lower overall cost. A well-defined pre-operative planning regime is absolutely mandatory.

Two stage exchange has been the gold standard in North America for the treatment of infected knee replacements. The choice of static versus articulated spacers has been debated for a number of years.

At our institution our choice of spacer for two-stage exchanges is an articulated spacer. This allows motion between stages which facilitates recovery, and makes the second stage technically easier. In a study from our institution we followed 115 infected TKAs treated with the PROSTALAC articulated spacer for 5–9 years. Success for eradication of infection was 88%. With a repeat two stage overall infection control was 98%. In addition we compared functional outcomes to a group of aseptic knee revisions and found no difference in functional outcomes with standard quality of life outcome scores.

While the articulated spacer was our treatment of choice in two-stage exchange around 2012 the company that manufactured the PROSTALAC knee components ceased to manufacture them. At that time based on the work of 2 previous studies (Hofmann, Lee), our institution continued to use articulated spacers. However, this was now the so-called Hofmann technique with a new standard femoral component with an all-polyethylene tibia. The only difference from a standard knee revision was no stems and the utilisation of high dose antibiotics. We also followed the principles from Europe of one-stage exchange, such as wide debridement and soaking in dilute betadine for 15 minutes.

More recently, as of Sept 2015, we have used an all-polyethylene tibia with a keel. The hope being that this will give a more stable tibia than previous and perhaps make a second stage unnecessary. Our first case was September 2015. The intention was not to do a second stage if the infection was eradicated and the patient had good pain relief and function. To date we have implanted 12 of these and in all cases we have not had to do a second stage revision. Further study will reveal where this inadvertent one stage fits in our practice.

Prevention and treatment of total joint infection is closely related to biofilm formation and concentration of antibiotics achieved in the area around the implants. Most total joint infections are caused by bacteria that enter the wound at the time of the operation. These bacteria can attach to surfaces and rapidly form biofilm that is highly resistant to antibiotics. Prophylactic antibiotics given intravenously achieve concentration of local antibiotics in the knee in response to intravenous antibiotics about 1/3 of that achieved in the serum, and the level is transient. This may be enough to treat the planktonic form of the bacteria, but far from enough to treat the biofilm. The concentration of antibiotics in the joint fluid achieved with antibiotics applied locally during surgery is 1000 times higher, and can be maintained throughout the procedure. High concentration persists in drainage fluid for 24 hours after surgery. Studies done with use of local antibiotics in spinal implant surgery indicate a major reduction in the rate of infection, and cost analysis shows remarkable monetary benefit to this effect.

Infected total joints benefit especially from direct application of antibiotics to the local area. 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 (average of 6.8 and 9,242µg/mL, respectively). 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 thousands of times 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 4.2µg/mL, respectively). The elimination constant (half-life) of IA-administered vancomycin was 3.1 hours.

Directly infusing antibiotics into the infected area maintains a high local concentration level while minimizing 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.

Preventing and treating infection in orthopaedic implant surgery requires achieving concentrations that are above the minimal biofilm eradication concentration. This can be achieved only with direct application.

There is great debate around how to treat patients with periprosthetic joint infections and there are different techniques utilised throughout the world with large regional differences. In the situation where implants are well fixed there is a potential advantage to retain ingrown implants in which removal would result in severe bone damage. However, there are multiple variables on both the patient side and the surgeon side which can influence the likelihood of success with this approach. In some patients, staged revision of large and well-fixed components will result in bone damage and compromised function, but the two-stage techniques may have great success at long term infection free survivorship. The literature suggests that selective implant retention and joint débridement may be an alternative for those patients who have complex well-fixed components, are not immunocompromised, have not developed sinus formation, and who have less virulent organisms on aspiration. Implant retention techniques should be approached with caution when patients have chronic illness such as diabetes or rheumatoid disease, use immunosuppressive medications, have a negative aspirate for microorganisms, or show any signs of loosening on radiographs or during intra-operative assessment. Like many aspects of patient care, proper patient selection and meticulous surgical techniques are important components to increasing success in these difficult clinical scenarios. This talk will focus on the data currently available in the literature to help participants gain a better understanding of how to individualise treatments for patients with periprosthetic infections.

Converting UKA to TKA can be difficult, and specialised techniques are needed. Issues include bone loss, joint line approximation, sizing, and rotation. Determining the complexity of conversion pre-operatively helps predict the need for augmentation, grafting, stems, or constraint.

In a 2009 study from our center, 50 UKA revised to TKA (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. 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.

In a 2013 multicenter study of 3 institutions including ours, a total of 175 revisions of medial UKA in 168 patients (81 males, 87 females; average age of 66 years) performed from 1995 to 2009 with a minimum of 2-year clinical follow-up were reviewed. The average time from UKA to revision TKA was 71.5 months (range: 2 months to 262 months). The four most common reasons for failure of the UKA were femoral or tibial loosening (55%), progressive arthritis of the lateral or patellofemoral joints (34%), polyethylene failure (4%) and infection (3%). Mean follow-up after revision was 75 months. Nine of 175 knees (4.5%) were subsequently revised at an average of 48 months (range 6 months to 123 months.) The rate of revision was 1.23 revisions per 100 observed component years. The average Knee Society pain and function score increased to 75 and 66, respectively. In the present series, the re-revision rate after revision TKA from UKA was 4.5 % at an average of 75 months or 1.2 revisions per 100 observed component years.

In a current study from our center, 174 patients (180 UKA) underwent revision procedures (1996–2017). Most prevalent indications for revision were aseptic loosening (45%) arthritic progression (17%) and tibial collapse (13%). At 4 years mean follow-up, 5 knees (2.8%) have required re-revision involving any part, which is similar to what we recently reported at 5.5 years in a group of patients who underwent primary TKA (6 of 189; 3.2%), and much lower than what we observed at 6.0 years in a recent report of patients who underwent aseptic revision TKA (35 of 278; 12.6%).

Compared to published individual institution and national registry data, re-revision of a failed UKA is equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA.

Exposure for revision knee requires using the previous incision, employing the “quad snip”, the “Banana Peel”, or the tubercle osteotomy.

The “quad snip” is a 45-degree incision of the proximal extensor mechanism that helps protect the distal insertion on the tubercle.

The “banana peel,” is my exposure of choice and has been used extensively for revision total knee arthroplasty (TKA) for more than 20 years in my community. We retrospectively reviewed use of this technique in a cohort of 100 consecutive patients who underwent tibial-femoral stemmed revision TKA. The technique involves peeling the patella tendon as a sleeve off the tibia, leaving the extensor mechanism intact with a lateral hinge of soft tissue. A quadriceps “snip” must be done proximally to avoid excessive tension. No patient has ever reported disruption of the extensor mechanism or decreased ability to extend the operative knee. With a mean Knee Society score of 176 (range, 95–200). Post-operative motion was 106 degrees. No patient reported pain over the tibial tubercle. The “banana peel” technique for exposing the knee during the revision TKA is a safe method that can be used along with a proximal quadriceps snip and does not violate the extensor mechanism, maintaining continuity of the knee extensors.

As a last resort, tibial tubercle osteotomy as described by Whiteside, is preferred for revising porous coated stemmed tibial components and is repaired with cerclage wire or cables. Keep the osteotomy fragment at least 8–10cm long leaving a lateral soft tissue attachment.

Liner exchange and bone grafting are commonly used in cases of wear and osteolysis around well- fixed acetabular components in revision total hip arthroplasty. However, in total knee revision, liner exchange is a more rare option.

In a multicenter study, we evaluated 22 TKAs that were revised with liner exchange and bone grafting for wear and osteolysis. All knees were well-fixed and well-aligned, and all components were modular tibial components. Osteolytic areas averaged 21.1cm2 and 7.6cm2 on AP projections of the femur and tibia, respectively, and averaged 21.6cm2 and 5.7cm2 on lateral projections of the femur and tibia, respectively, with the largest area being 54cm2 on a single projection. Follow up was minimum 2 years and average 40 months. No knees were revised and radiographically, all osteolytic lesions showed evidence of complete or partial graft incorporation. In addition, there was no radiographic evidence of loosening at final follow up.

The Mayo Clinic evaluated 56 isolated tibial insert exchange revisions at their institution. Cases of loosening, infection, knee stiffness, or extensor mechanism problems were excluded. At minimum 2-year follow up (average 4.6 years), 14 knees (25%) required re-revision.

Baker et al. evaluated 45 total knees undergoing isolated tibial insert exchange. At minimum 2 years, 4 knees (9%) required revision. Significant improvement was seen in clinical outcomes questionnaires, but only 58% had clinical successful global WOMAC scores.

In summary, isolated liner exchange in the revision total knee setting has variable results. It can be successful but it is indeed a rare option and should be limited to cases were the total knee arthroplasty is both well-fixed and well-aligned.

There are many challenges facing the revision knee surgeon. Bony defects, ligamentous imbalance, and difficult gap balancing scenarios are common and require practical management strategies. Typically, an implant with the least amount of constraint necessary to provide a well-aligned, well-balanced arc of motion is preferred. Constraint in implants increases the stresses on both the bearing surfaces and the bony interfaces and may result in earlier mechanical failure of the implant. Despite this fact, there are situations where one cannot rely on a simple larger polyethylene post (such as found in CCK type devices) to balance gaps. The author prefers to choose hinge-type devices in situations that demonstrate massive gap imbalance (typically huge flexion gaps), situations with deficient extensor mechanisms that can result in recurvatum stresses, or in situations of global ligamentous instability. Techniques of supporting the bony interfaces with stems and sleeves may improve the longevity of these constructs. Complications are common, including extensor mechanism problems. Multiple studies have demonstrated reasonable results of hinged implants for these challenging revision scenarios, and the hinge should remain in the armamentarium of the revision surgeon.

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 (TKA). 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 pre-operative 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 as it 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: 1) Fill with cement; 2) Fill with cement supplemented by screws or K-wires; 3) Morselised 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. Maximizing support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis. Pre-operative planning is facilitated by good quality radiographs, supplemented on occasion by additional imaging such as CT. Fluoroscopically controlled x-ray views may assist in diagnosing the loose implant by better revealing the interface between the implant and bone and can facilitate accurate delineation of the extent of bone deficiency present. Part of the pre-operative plan is to ensure adequate range and variety of implant choices and bone graft resources for the planned reconstruction allowing for the potential for unexpected intra-operative findings such as occult fracture through deficient periprosthetic bone.

Reconstruction of bone deficiency following removal of the failed implant is largely dictated by the location and extent of bone loss and the quality of bone that remains. While massive bone loss may compromise ligamentous attachment to bone, in the majority of reconstructions the degree of implant constraint needed for proper balancing and restoration of stability is independent of the bone defect. Thus some knees with minimal bone deficiency may require increased constraint due to the status of the soft tissues while others involving very large bone defects especially of the cavitary sort may be well managed with minimal constraint.

Highly porous metal augments designed to reestablish metaphyseal support and function in the manner of a prosthetic structural graft have been introduced or are under development by several manufacturers. Published reports of short term experiences have been encouraging for both the tibial side and for femoral augmentation. It remains to be seen whether these implants will provide the desired longer term durability.

THA: Approaches and Recovery; THA: Instability and Spinal Deformity; Revision for THA Instability: Dual Mobility Cups; Removal of Infected THA: Risk Factors for Complications; Tribocorrosion: Incidence in the Symptomatic THA; THA: Outcomes and Education Levels; THA: Satisfaction levels and Residual Symptoms; THA: Expectations and LOS; TKA: Kneeling and Recreation Expectations; TKA: Alignment and Long Term Survival; Patello-Femoral Arthroplasty vs TKA; Unicompartmental Knee Arthroplasty and Age; Wound Treatments and Sepsis in TJA; TKA: Managing Sepsis With I & D; Chronic Salvage in TKA: When is Enough Enough?; Revision TKA: Single Component Revision

The anterior approach is now an accepted approach for total hip arthroplasty. First described over a century ago, its popularity has grown significantly in the last decade with the advent of a reproducible technique on an orthopaedic table. Potential advantages include quicker recovery times, less post-operative pain, improved hip biomechanics, and more accurate cup position. While both femoral exposure and learning curve are often cited as potential drawbacks, a large percentage of US surgeons now utilise this teachable approach. The adoption of this approach has facilitated the development of new tools to assist the arthroplasty surgeon in a more efficient and efficacious manner.

The anterior approach is performed with the patient in a supine position on an orthopaedic table. The supine position provides improved visualization of the acetabulum, appreciation of pelvic position as well as the advantage of intra-operative fluoroscopy. While many technologies including navigation and first generation robotics exist to assist the surgeon with virtual information; only fluoroscopy provides the surgeon with real time actual information. The interpretation of fluoroscopic images carries a learning curve and potential for error. New technology now exists to assist the surgeon to better interpret fluoroscopic images including anteversion and abduction of cup, leg length and offset.

Since the first hip surgery was performed by Sir John Charnley, hip surgeons have utilised specialised tools including reamers, drills, saws, and mallets during surgery to assist with cup insertion, femoral preparation, stem insertion, liner insertion and head impaction. Many tools in the operating room including drills, reamers, and saws have moved from hand powered operation to pneumatic and now battery powered operation to assist with efficiency, efficacy, and reduced surgeon fatigue. A new, battery powered impaction device provides a consistent and constant energy that does not rely on the surgeon's mallet speed, throw distance, or impact contact. This may represent the next generation of surgical tools available to the arthroplasty surgeon that has the potential to make the mallet obsolete.

There are three major diagnoses that have been associated with early hip degeneration and subsequent hip replacement in young patients: FAI, hip dysplasia and hip osteonecrosis. I will focus mainly on the first two. Both conditions, if diagnosed early in the symptomatic patient, can be surgically treated in order to try to prevent further hip degeneration. But, what is the natural history of these disorders?

Our recent paper published this year described the natural history of hip dysplasia in a group of patients with a contralateral THA. At an average of 20 years, 70% of hips that were diagnosed at Tönnis Grade 0, had progression in degenerative changes with 23% requiring a THA at 20 years. Once the hip degeneration progressed to Tönnis 1, then 60% of hips progressed and required a THA. This natural history study demonstrates that degeneration of a dysplastic hip will occur in over 2/3 of the hips despite the limitations of activity imposed by a contralateral THA.

In this same study, we were unable to detect a significant difference in progression between FAI hips and those categorised as normal. FAI damage has been commonly considered to be “motion-induced” and as such, the limitations imposed by the THA, might have limited the progression in hip damage. Needless to say, progression was seen in about half of the hips at 10 years, but very few required a THA at final follow-up. We have recently presented data on a group of young asymptomatic teenagers with FAI. At 5 years of follow-up, the group of patients with limited ROM in flexion and internal rotation, cam deformity and increased alpha angles, depicting a more severe form of disease, showed MRI evidence of progression in hip damage and worst clinical scores than a control group. This data supports our initial impressions that FAI may truly lead to irreversible hip damage.

Is surgery always the option? I indicate surgery when the patient is symptomatic and has a correctable structural problem that has failed non-operative management. The data suggests that few patients improve with physical therapy, but activity modification may be an option in patients with FAI as the hip damage is mainly activity related. This may not be the case with hip dysplasia. For hip dysplasia, my current recommendations are in the form of a periacetabular osteotomy (PAO) to correct the structural problem. The procedure leads to improvement in pain as it takes care of the 4 pain generators in the dysplastic hip: the labrum, cartilage, abductors, and resultant instability. The labrum and cartilage are off-loaded with the PAO, the instability is improved by providing containment and the abductor pain is improved by improving the hip mechanics by medializing the acetabulum. I perform a hip arthroscopy prior to the PAO in the majority to treat the labrum and to perform a head neck junction osteochondroplasty, if needed. Correction of the dysplasia to a more normal hip, will improve the outcome of these hips in the long-term.

For FAI, arthroscopy has become the best option for management and today is considered the gold standard. A careful review of the imaging is important prior to surgical decision making as patient selection and surgical correction is key. Poor outcomes have been seen in patients with advanced degenerative changes (joint space narrowing, femoral head damage) or in patients with incomplete correction of the deformity. Open surgical correction is an option in cases where deformity precludes an arthroscopic treatment alone.

Contemporary polyethylene liners for total hip replacements were introduced in the late 1990's to address osteolysis associated with wear of conventional polyethylene. Every major device manufacturer introduced an “enhanced polyethylene”. In the ensuing decade plus, every major arthroplasty meeting had presentations and debates about the wear resistance and mechanical properties of these new polymers. The results have been remarkable and now with 17 to 18 years of use in patients, we have yet to see clinically significant osteolysis in our patients regardless age or activity level.

The results can be summarised as follows: All currently commercially available highly crosslinked polyethylenes produced by major device companies have demonstrated a reduction in wear and osteolysis. At the 2016 Closed Meeting of The Hip Society, none of the surgeons attending had seen a clinically significant case of osteolysis associated with highly crosslinked polyethylene. Registry data demonstrates the superiority of the highly crosslinked materials over conventional polyethylenes.

Historical concerns over a reduction in mechanical properties have not been borne out in clinical studies. Although highly crosslinked polyethylene liner fractures have been reported, they are rare and probably related to specific designs or surgical technique issues. It is important to remember that there were rare cases of fracture of conventional polyethylene as well.

With currently reported wear rates of the enhanced polyethylenes, polyethylene thickness is unlikely to be a factor in long-term durability with well-designed sockets. Bench data has demonstrated that polyethylene thickness is not a risk factor for wear or fracture if well supported by the metal shell. Thin unsupported polyethylene is at risk for fracture.

Although the new anti-oxidant polyethylenes (eg. Vitamin E) have performed well in wear studies, there is no clinically available evidence to support their use based on enhanced fracture toughness.

Ceramic-on-ceramic bearings provide a solution to the osteolysis seen with traditional metal-on-polyethylene bearings. Sporadic reports of ceramic breakage and squeaking concern some surgeons and this bearing combination can show in vivo signs of edge loading wear which was not predicted from in vitro studies. Taper damage or debris in the taper between the ceramic and metal may lead to breakage of either a ceramic head or insert. Fastidious surgical technique may help to minimise the risk of ceramic breakage. Squeaking is usually a benign complication, most frequently occurring when the hip is fully flexed. Rarely, it can occur with each step of walking when it can be sufficiently troublesome to require revision surgery. The etiology of squeaking is multifactorial origin. Taller, heavier and younger patients with higher activity levels are more prone to hips that squeak. Cup version and inclination are also relevant factors.

Fifty-five ceramic bearings revised at our center were collected over 12 years. Median time to revision was 2.7 years. Forty-six (84%) cases had edge loading wear. The median femoral head wear volume overall was 0.2mm³/yr, for anterosuperior edge loading was 2.0mm³/yr, and the median volumetric wear rate for posterior edge loading was 0.15mm³/yr (p=0.005).

Osteolysis following metal-on-polyethylene total hip arthroplasty (THA) is well reported. Earlier generation ceramic-on-ceramic bearings did produce some osteolysis, but in flawed implants. As 3rd and now 4th generation ceramic THAs come into mid- and long-term service, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. The technique used by radiologists for identifying the nature of lesions on Computed Tomography (CT) scan is the Hounsfield score which will identify the density of the tissue within the lucent area. Commonly the radiologist will have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA, which states there is osteolysis? This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term 3rd generation ceramic-on-ceramic uncemented hip arthroplasties in our department.

Total hip arthroplasty is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA.

The current generation metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify.

To generate data on the level of function of younger more active arthroplasty patients, a national multicenter survey was conducted by an independent university medical interviewing center with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centers throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. In another study of over 400 THA and SRA patients at two major academic centers, patients completed pain drawings that revealed an equivalent incidence of groin pain between THA and SRA, but an incidence of thigh pain in THA that was three times higher than in SRA in young active patients.

While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilisation and investigation of this procedure.

The number of cemented femoral stems implanted in the United States continues to slowly decrease over time. Approximately 10% of all femoral components implanted today are cemented, and the majority are in patients undergoing hip arthroplasty for femoral neck fractures. The European experience is quite different, in the UK, cemented femoral stems account for approximately 50% of all implants, while in the Swedish registry, cemented stems still account for the majority of implanted femoral components. Recent data demonstrating some limitations of uncemented fixation in the elderly for primary THA, may suggest that a cemented femoral component may be an attractive alternative in such a group.

Two general philosophies exist with regards to the cemented femoral stem: Taper slip and Composite Beam. There are flagship implants representing both philosophies and select designs have shown excellent results past 30 years. A good femoral component design and cementing technique, however, is crucial for long-term clinical success. The authors' personal preference is that of a “taper slip” design. The cemented Exeter stem has shown excellent results past 30 years with rare cases of loosening. The characteristic behavior of such a stem is to allow slight subsidence of the stem within the cement mantle through the process of cement creep. One or two millimeters of subsidence in the long-term have been observed with no detrimental clinical consequences. There have been ample results in the literature showing the excellent results at mid- and long-term in all patient groups.

The authors' current indications for a cemented stem include the elderly with no clear and definitive cutoff for age, most likely in females, THA for femoral neck fracture, small femoral canals such as those patients with DDH, and occasionally in patients with history of previous hip infection. Modern and impeccable cement technique is paramount for durable cemented fixation. It is important to remember that the goal is interdigitation of the cement with cancellous bone, so preparing the femur should not remove cancellous bone. Modern technique includes distal plugging of the femoral canal, pulsatile lavage, drying of the femoral canal with epinephrine or hydrogen peroxide, retrograde fill of the femoral canal with cement with appropriate suction and pressurization of the femoral cement into the canal prior to implantation of the femoral component.

The dreaded “cement implantation syndrome” leading to sudden death can be avoided by appropriate fluid resuscitation prior to implanting the femoral component. This is a extremely rare occurrence today with reported mortality for the Exeter stem of 1 in 10,000.

A cemented femoral component has been shown to be clinically successful at long term. Unfortunately, the art of cementing a femoral component has been lost and is rarely performed in the US. The number of cemented stems unfortunately may continue to go down as it is uncommonly taught in residency and fellowship, however it might find a resurgence as the limits of uncemented fixation in the elderly are encountered. National joint registers support the use of cemented femoral components, and actually demonstrate higher survivorship at short term when compared to all other uncemented femoral components. A cemented femoral component should be in the hip surgeons' armamentarium when treating patients undergoing primary and revision THA.

Over the past several decades, cementless femoral fixation for primary total hip arthroplasties (THAs) has become more common in North America. It is estimated that nearly 90% of all primary THAs completed in the United States are cementless. In the Australian National Joint Replacement Registry, the use of cementless fixation has increased from 51.3% in 2003 to 63.3% in 2015. During the same time period, cemented fixation declined from 13.9% to 3.7%, but hybrid fixation was relatively stable at about 33%. This is likely related to the fact that multiple institutional and national registries have shown a higher rate of intra-operative periprosthetic femoral fractures with the use of cementless femoral components in certain patient populations. Those risk factors include patients greater than 65 years of age, female patients, and those with significant osteoporosis and Dorr C canals.

However, it is important to note that not all cementless femoral components are similar. In fact, there is great variation in not only the geometry of cementless femoral components, but also in the type and extent of the biologic ingrowth surfaces. Each design has unique advantages and disadvantages. While some cementless femoral components are indicated for the general population, some are more specific and tailored to complex primary THAs (such as developmental dysplasia of the hip or post-traumatic arthritis with intra-operative concern for femoral version and thus hip stability) or revision procedures where distal fixation is needed (such as those with periprosthetic fractures or lack of proximal metaphyseal bony support).

In 2000, Berry first described the evolution of cementless femoral components based upon distinct geometries that govern where fixation is obtained. This was modified in 2011 by Khanuja et al. to include six general types of cementless femoral components based upon shape. These include the following: Type 1: Single wedge; Type 2: Double edge with metaphyseal filling; Type 3: Tapered - A: Tapered round, B: Tapered spline/cone, C: Tapered rectangle; Type 4: Cylindrical fully coated; Type 5: Modular; Type 6: Anatomic.

Type 1, 2, and 6 cementless femoral components obtain fixation in the metaphysis, whereas Type 3 stems obtain fixation in the metaphyseal-diaphyseal junction. Type 4 stems obtain fixation in the diaphysis. Type 5 stems can obtain fixation in either the metaphysis or the diaphysis.

Within each type of stem, specific implant designs have had excellent long-term survivorship, while other specific implant designs have had higher than expected failure rates. Type 1 stems have the most published reports, and most contemporary reports indicate a stem survivorship greater than 95% at 15–20 years. Similar findings have been documented with specific implants from other types of stems when appropriate indications and surgical technique are utilised. Of note, one class of stems that has shown early failures due to adverse local tissue reactions (ALTR) is that of dual-modular necks. On the other hand, modular fluted tapered stems continue to produce excellent long-term data in complex primary THAs, as well as difficult revision THAs.

Uncemented metal-on-polyethylene total hip arthroplasties (THAs) have had a modular cobalt-chrome alloy head since their introduction in the early 1980's. Retrieval analysis studies and case reports in the early 1990's first reported corrosion between the femoral stem trunnion (usually titanium alloy) and cobalt-chrome alloy femoral head. However, then this condition seemed to disappear for about two decades? There are now numerous recent case series of this problem after metal-on-polyethylene THA, with a single taper or dual taper modular femoral component. Metal ion elevation, corrosion debris, and effusion are caused by mechanically assisted crevice corrosion (MACC). These patients present with diffuse hip pain, simulating trochanteric bursitis, iliopsoas tendinitis, or even deep infection. Trunnion corrosion, with adverse local tissue reaction, is a diagnosis of exclusion, after infection, loosening, or fracture. The initial lab tests recommended are: ESR, CRP, and serum cobalt and chromium ions. With a metal-on-polyethylene THA, a cobalt level > 1ppb is abnormal. Plain radiographs are usually negative, but may show calcar osteolysis or acetabular erosion or cyst. MARS MRI may be the best imaging study to confirm the diagnosis. Hip aspiration for culture and cell-count may be necessary. The operative treatment is empiric, with debridement, and head exchange with a ceramic head-titanium sleeve (or oxidised zirconium head) placed on the cleaned trunnion. The femoral component may have to be removed if there is “whole trunnion failure”. This usually relieves the symptoms, but the complication rate of this procedure may be high.

Increasing data is emerging, consistently demonstrating a more rapid recovery for patients undergoing direct anterior approach (DAA) surgery. In one study, objective findings of early recovery including timed up and go tests, Functional Independence Measures are significantly faster in the first 2 weeks, and normalise by 6 weeks. A more recent randomised study shows a quicker achievement of the functional milestones of discontinuing walking aids, discontinuing opioids, stair ascent, and walking 6 blocks, as well as accelerometer measures of activity in the first 2 weeks after surgery. In both of these studies, seasoned surgeons well beyond their learning curves performed the surgeries.

A prospective MRI study of volume before and after surgery has shown full recovery or mild hypertrophy of most muscles at an average of 24 weeks from surgery, but a sustained loss of muscle volume for the obturator internus muscle in the DAA, and sustained loss of muscle volume for obturator internus, obturator externus, piriformis, and quadratus femoris in the posterior approach patients. The muscles that are released in the surgeries recover incompletely.

Prospective assessment of muscle strength demonstrated loss of flexion strength in the DAA group and loss of external rotation strength in the posterior group at 6 weeks. By 3 months, the DAA group had returned to normal in their strength, while the posterior group had persistent external rotation weakness.

Prospective assessment of gait, pre-operatively and at 6 months showed similar improvements in frontal and sagittal plane range of movement in gait, with a similar improvement in transverse plane movement (internal and external rotation) in the DAA group, but no change in the posterior cohort.

The precision of socket placement, after undergoing a learning curve, was greater with the use of fluoroscopy in the DAA.

Cutting and subsequently repairing a muscle can have a clinically insignificant, but nonetheless objectively measurable effect on the function of that muscle.

Observed downsides of DAA include a higher prevalence of wound complications in obese patients, and possibly a higher risk of periprosthetic fractures in elderly, thin women. Recent larger registry data would also suggest that there is no difference in dislocation rate between the 2 referenced approaches, and possibly a higher femoral revision rate for the DAA. These may be honest and real depictions of a large learning curve as we further understand and disseminate the subtleties of proper execution of DAA surgery.

Goals for total hip arthroplasty include acceleration of recovery, optimisation of component placement, minimisation of peri-operative complications, and maximal preservation of surrounding soft tissues. Achieving these goals when combined with appropriate implant design and manufacture can lead to decades of excellent hip function.

With the exception of relatively rapid recovery, which can also be achieved with virtually all modern surgical exposures, the anterior hip approach fails to reliably achieve these goals. Problems with the anterior exposure for total hip arthroplasty are becoming increasingly recognised. Complications with equal or higher incidences than alternative exposures include: 1.) Early wound complications, 2.) Infection, 3.) Intra-operative and post-operative femur fracture, 4.) Greater trochanteric fracture, 5.) Dislocation, 6.) Femoral component loosening, 7.) Poor component placement, 8.) Poor soft tissue balance, 9.) Incisions with poor aesthetics and associated superficial hypaesthesia and dysaesthesia.

These complications may be in part due to: 1.) The anterior and posterior soft tissue releases often necessary to complete the exposure, 2.) Poor ability to anatomically repair the hip joint capsule, 3.) Reduced choices of femoral components with restriction generally to those with less robust fixation, 4.) The poorly extensile nature of the interval, 5.) The need to place the incision in the region of the flexion crease, 6.) The limited ability to assess soft tissue balance and impingement-free range of motion at the time of surgery, 7.) The undue reliance on unvalidated, inaccurate imaging techniques to assess component placement.

While experienced surgeons can achieve excellent results with the anterior (or virtually any other) exposure for total hip arthroplasty, the anterior exposure is by no means close to being a first among equals.

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 or ceramic head is snap-fit into the large polyethylene. In some European centers, these components are routinely used for primary total hip arthroplasty. However, their greatest utility will be to prevent and manage recurrent dislocation in the setting of revision total hip arthroplasty. Several retrospective series have shown satisfactory results for this indication at medium-term follow-up times. The author has used dual mobility components on two occasions to salvage a failed constrained liner. At least one center reports that dual mobility outperforms 40mm femoral heads in revision arthroplasty. Modular dual mobility components, with screw fixation, are the author's first choice for the treatment of recurrent dislocation, revision of failed metal-metal resurfacing, total hips, unipolar arthroplasties, and salvage of failed constrained liners. There are concerns of elevated metal levels with one design, and acute early intra-prosthetic dissociation following attempted closed reduction. Total hip surgeons no longer cement Charnley acetabular components, use conventional polyethylene, autologous blood donation, or a drain; now constrained components join these obsolete techniques! In 2017, a dual mobility component, rather than a constrained liner, is the preferred solution in revision surgery to prevent and manage recurrent dislocation.

In primary total hip replacements there are numerous options available for providing hip stability in difficult situations (i.e. Down's syndrome, Parkinson's disease). We have considered constrained liners in some of these cases.

However, in the revision situation in general and in revision for recurrent dislocation situation specifically it is important to have all options available including tripolar constrained liners in order to optimise the potential for hip stability as well as function of the arthroplasty. Even with the newer options available dislocation rates of higher than 10–15% have been reported following revision surgery at institutions where high volumes of revision surgery are performed. Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups revision cases will always have more potential for dislocation. In these situations in the lower demand patient, constraint has provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate- term follow-up. Hence in these situations tripolar constrained liners remains the option we utilise. We are also confident in using this device in cases with instability or laxity where there is a secure well- positioned acetabular shell. We cement a dual mobility constrained liner in these situations using the technique described below.

Present indication for tripolar constrained liners: low demand patient, large outer diameter cups, instability with well-fixed shells that are adequately positioned, abductor muscle deficiency or soft tissue laxity, multiple operations for instability

Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle

Despite the prophylactic use of antibiotics and hygienic strategies, surgical site infection following total joint arthroplasty (TJA) is still a severe and unsolved complication. Since antibiotic-loaded bone cement (ALBC) was introduced by Buchholz in the 1970s, the use of ALBC has been increasingly used for the prevention and treatment of periprosthetic infection (PPI). However, the routine use of ALBC during primary TJA remains controversial. Recent clinical studies have found that ALBC is effective in reducing the risk of PJI following primary TJA. Although ALBC having the advantage of reducing the risk of PJI, the main disadvantages are the possible development of toxicity, antibiotic resistance, allergic reaction, and possible reduction of the mechanical properties of bone cement. Nevertheless, a recent published article demonstrated, that the use of high dose dual-antibiotic impregnated cement reduce significantly the rate of surgical site infections compared to standard low dose single ALBC in the setting of a hip fracture treating with hemiarthroplasty. Furthermore, Sanz-Ruiz et al. presented that the use of ALBC in TJA has favorable cost-efficiency profile. In this context, reasons why surgeons should use antibiotic-loaded bone cement during primary TJA are demonstrated.

Periprosthetic infection after total joint replacement is a catastrophic complication. Current rates of infection have been decreasing and in most centers now are in the range of 0.1–1%. Peri-operative intravenous antibiotic therapy is used routinely in total hip arthroplasty patients at this time. With rates this low and mixed evidence that antibiotics in bone cement for routine total hip replacement are beneficial at reducing joint infection, routine use of this practice seems unnecessary and has potential disadvantages. Cost of antibiotics being added to cement on a routine basis will increase the cost of the arthroplasty $300–$500. Although small addition of bone cement also has a negative effect on the mechanical properties of the cement. The major disadvantage remains the danger of resistant bacterial strains from excessive use of antibiotics particularly vancomycin resistant organisms when it is used routinely. Although rare with the aminoglycosides, allergic reactions may occur if cephalosporins are used as prophylaxis. Use of antibiotics in bone cement should be considered in high risk patients for infection undergoing total hip replacement but not routinely because of cost, emergence of resistant organism and possible allergic reaction.

Few will disagree that the best femoral head that a young patient can have is his or her own, native femoral head. In the active, healthy patient under age 60 with a displaced femoral neck fracture, well-done, timely ORIF presents the best chance of preserving the patient's native femoral head. Arthroplasty is generally reserved for older patients, over age 60, where attempts at ORIF in this setting have demonstrated failure rates over 40%. “Physiologic age” is a somewhat nebulous term that takes into account the health and ambulatory status of the patient. For example, a 52-year-old with end stage renal failure, severe osteoporosis, and a displaced femoral neck fracture may best be treated with arthroplasty. However, in reality, such situations are quite rare. Recent studies have documented that approximately 80% of young patients with displaced femoral neck fractures treated with ORIF will keep their own femoral head for 10 years after injury. The variables under the surgeon's control include timing of fixation, quality of reduction, accurate implant placement and implant selection, and capsulotomy. All of these variables potentially affect outcomes. Fractures in this young age group are frequently high shear angle (vertical) Pauwels Type 3 fractures, and benefit from fixed angle fixation. The author prefers anatomic reduction and stabilisation with a sliding hip screw and a superiorly placed derotation screw. Careful attention to detail is important to obtain an anatomic reduction, which is the most important variable in the outcome of these challenging injuries.

Blood conservation is an essential aspect of total hip arthroplasty (THA). As recently as 10 years ago, it was standard practice across North America for patients to undergo pre-operative autologous blood donation (PAD) prior to an elective TJA. Though the cost of PAD is about the same as allogenic blood transfusion, it has fallen out of favor due to mixed results.

Instead, most surgeons have implemented a practice of obtaining pre-operative hemoglobin levels. If anemia is diagnosed, the patient should be worked up for the underlying cause. In cases of pre-operative anemia where a specific deficiency cannot be elucidated, consideration can be given to the use of erythropoietin (EPO).

The routine use of tranexamic acid (TXA) has become the standard of care at most institutions since it is safe, inexpensive, easy to administer, and very effective at minimizing peri-operative blood transfusion. Intravenous TXA can be administered effectively in a variety of different ways and a number of different protocols are described. The popularised Mayo Clinic protocol is to administer TXA once prior to incision (1g IV in 50mL of normal saline) and once during wound closure.

Acute normovolemic hemodilution is a technique utilised just before or after the induction of anesthesia in which whole blood is removed while keeping the patient normovolemic with acellular fluids (i.e. crystalloids or colloids). This technique is rarely used.

Hypotensive anesthesia is a technique utilised to keep mean arterial pressures (MAP) at a level around 50mm Hg. It appears to be most effective with the use of epidural anesthesia. Certain patients may not be good candidates for hypotensive anesthesia (high cardiac risk factors), but it can be an effective corollary to other intra-operative measures.

Historically, many surgeons practiced reflexive transfusion protocols rather than treating patients on an individual basis. Current practice has adopted a more pragmatic approach to transfusion. Specifically, patients are assessed for signs of anemia and are often allowed to drift well below 8g/dL as long as they remain asymptomatic and have a suitable cardiac risk.

The US obesity epidemic has transcended into the arthroplasty patient population and surgeons must assess whether obesity is a risk factor for poor outcomes in total joint arthroplasty (TJA) and determine how it should be managed in order to insure good clinical outcomes. In the United States, 34.9% of adults are currently obese (BMI > 30). In a recent study, 54.5% of patients reporting to arthroplasty clinics in the US were obese. We performed a recent literature review to determine how obesity impacts outcomes in total hip and knee arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient.

We know that obesity and its associated comorbid conditions do have worse outcomes and increased complications in TJA patients. We also know that complications proportionately increase with increasing severity of obesity. The super-obese population is at the greatest risk of complication following TJA and pre-operative screening and management is essential in reducing complications. Although weight loss is important, our bariatric data has shown that it does not solve the problem of obesity in itself and the patient's metabolic state is likely a more important issue. Implant selection is important and strong consideration should be given to avoiding direct anterior approach in the THA obese patient. Understanding of obesity specific complications and treatment options is crucial for patient counseling and optimisation to ensure successful treatment in obese TJA patients.

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intra-operative fracture) are careful pre-operative planning and more recently, the option of intra-operative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intra-operative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the pre-operative plan intra-operatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results.

Recurrent dislocation following total hip arthroplasty (THA) is a complex, multifactorial problem that has been shown to be the most common indication for revision THA. At our center, we have tried to approach the unstable hip by identifying the primary cause of instability and correcting that at the time of revision surgery.

Type 1:

Malposition of the acetabular component treated with revision of the acetabular component and upsizing the femoral head.

The most common etiologies of instability in our experience include cup malposition (Type 1) and abductor deficiency (Type 3).

We reviewed 75 hips revised for instability and at a mean 35.3 months 11 re-dislocations occurred (14.6%). Acetabular revisions were protective against re-dislocation (p<0.02). The number of previous operations (p=0.04) and previously failed constrained liners (p<0.02) were risk factors for failure. The highest risk of failure was in patients with abductor insufficiency with revisions for other etiologies having a success rate of 90%.

Although instability can be multifactorial, by identifying the primary cause of instability, a rational approach to treatment can be formulated. In general the poorest results were seen in patients with abductor deficiency. Given the high rate of failure of constrained liners (9 of the 11 failures were constrained), we currently are exploring alternatives such as dual mobility articulations. Our early experience with dual mobility suggests improved results when compared to constrained liners.

Metal-on-metal bearings (MoM) saw an increase in global utilisation in the last decade. This peaked in 2008 in the US, with approximately 35% of bearings being hard-on-hard (metal-on-metal, or ceramic-on-ceramic). Beginning in 2008, reports began to surface regarding local soft tissue reactions and hypersensitivity to MoM bearings. A major implant manufacturer recalled a resurfacing device in 2010 after national joint registries demonstrated higher than expected revision rates. Patients with painful MoM bearings are a difficult diagnostic challenge. The surgeon must go back to basic principles, perform a complete history and physical exam, obtain serial radiographs and basic blood work (ESR, CRP) to rule out common causes of pain and determine if the pain is, or is not, related to the bearing. The Asymptomatic MoM Arthroplasty: Patients will present for either routine follow up, or because of concerns regarding their bearing. It is important to emphasise that at this point the vast majority of patients with a MoM bearing are indeed asymptomatic and their bearings are performing well. The surgeon must take into account: a) which specific implant are they dealing with and what is its track record; b) what is the cup position; c) when to perform metal ion testing; d) when to perform further soft tissue imaging (MARS MRI, Ultrasound); e) when to discuss possible surgery. Painful MoM THA causes not related to the bearing couple: These can be broken down into two broad categories. Causes that are Extrinsic to the hip include spine, vascular, metabolic and malignancy. Causes that are Intrinsic to the hip can either be Extracapsular or Intracapsular. Painful MoM THA causes related to the bearing couple: There are now described a number of possible clinical scenarios and causes of pain that relate to the MoM bearing couple itself: A) Local hypersensitivity reaction without a significant soft tissue reaction; B) Local hypersensitivity reaction with a significant soft tissue reaction; C) Impingement and soft tissue pain secondary to large head effect. Factors related to a hypersensitivity reaction: Some patients, and prostheses, seem to be at a higher risk of developing issues following a MoM bearing, although our understanding of the interplay of these factors is still in evolution: patients at risk include all women and patients with smaller component sizes. Implant factors play a role with some implants having higher wear rates and being more prone to corrosion. Special tests: There is ongoing confusion related to the relative value of the various special tests that patients with a painful MoM undergo. A) Metal Ions - obtaining serum, or whole blood, cobalt and chromium levels is recommended as a baseline test. However, there is no established cutoff level to determine with certainty if a patient is having a hypersensitivity reaction. Metal ions therefore can be used as a clue, but cannot be relied upon in isolation to make a diagnosis. B) MARS MRI - a useful tool for demonstrating soft tissue involvement, but there are many painless, well-functioning MoM implants that have soft tissue reactions, that don't require a revision. In the painful MoM hip an MRI, or ultrasound, is recommended to look for soft tissue destruction or a fluid-filled periprosthetic lesion (pseudotumor). Significant soft tissue involvement is concerning and is commonly an indication for revision in the painful MoM hip. C) CT imaging - can be utilised to help determine cup position and combined anteversion, however, plain radiographs can give a rough estimate of this as well, so routine CT scan evaluations are not currently recommended. The painful MoM bearing, that is demonstrating significant soft tissue involvement is a concerning scenario. Earlier revision, to prevent massive abductor damage, would seem prudent for these patients.

The painful MoM bearing with no significant soft tissue changes can probably be followed and reviewed at regular intervals. If the pain persists and is felt to be secondary to a hypersensitivity reaction, then revision is really the only option, although the patient must be cautioned regarding the unpredictable nature of the pain relief.

The challenges faced by hip surgeons have changed over the last decade. Historically, fixation, polyethylene wear, osteolysis, loosening and failure to osseointegrate dominated the discussions at hip surgery meetings. With the introduction of highly crosslinked polyethylene, wear and osteolysis are currently not significant issues. Improved surgical technique has resulted in a high rate of osseointegration and once fixed, loosening of cementless components is rare.

In this section, we will focus on issues that orthopaedic surgeons performing hip surgery routinely face including bearing couples in the young active patient, implant choices in the dysplastic hip and osteoporotic femur, evaluation and management of the unstable hip and differential diagnosis of the painful THR.

Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair.

The primary workhorses of bone grafting include autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because it is present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs.

The first bone graft substitute use was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly four types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don't end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval.

As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential.

As the number of patients who have undergone total hip arthroplasty rises, the number of patients who require surgery for a failed total hip arthroplasty is also increasing. It is estimated that 183,000 total hip replacements were performed in the United States in the year 2000 and that 31,000 of these (17%) were revision procedures. Reconstruction of the failed femoral component in revision total hip arthroplasty can be challenging from a technical perspective and in pre-operative planning. With multiple reconstructive options available, it is helpful to have a classification system which guides the surgeon in selecting the appropriate method of reconstruction. A classification of femoral deficiency has been developed and an algorithmic approach to femoral reconstruction is presented.

Type I:

Minimal loss of metaphyseal cancellous bone with an intact diaphysis. Often seen when conversion of a cementless femoral component without biological ingrowth surface requires revision. Type II: Extensive loss of metaphyseal cancellous bone with an intact diaphysis. Often encountered after the removal of a cemented femoral component. Type IIIA: The metaphysis is severely damaged and non-supportive with more than 4cm of intact diaphyseal bone for distal fixation. This type of defect is commonly seen after removal of grossly loose femoral components inserted with first generation cementing techniques. Type IIIB: The metaphysis is severely damaged and non-supportive with less than 4cm of diaphyseal bone available for distal fixation. This type of defect is often seen following failure of a cemented femoral component that was inserted with a cement restrictor and cementless femoral components associated with significant distal osteolysis. Type IV: Extensive meta-diaphyseal damage in conjunction with a widened femoral canal. The isthmus is non-supportive.

An extensively coated, diaphyseal filling component reliable achieves successful fixation in the majority of revision femurs. The surgical technique is straightforward and we continue to use this type of device in the majority of our revision total hip arthroplasties. However, in the severely damaged femur (Type IIIB and Type IV), other reconstructive options may provide improved results.

The technique involves impaction of cancellous bone into a cavitary femur. If segmental defects are present, the defects can be closed with stainless steel mesh. The technique requires retrograde fill of the femoral cavity with cancellous chips of appropriate size to create a new endomedullary canal. By using a set of trial impactors that are slightly larger than the real implants the cancellous bone is impacted into the tube. Subsequent proximal impaction of bone is performed with square tip or half moon impactors. A key part of the technique is to impact the bone tightly into the tube especially around the calcar to provide optimal stability. Finally a polished tapered stem is cemented using almost liquid cement in order to achieve interdigitation of the implant to the cancellous bone.

The technique as described is rarely performed today in many centers around the world. In the US, the technique lost its interest because of the lengthy operative times, unacceptable rate of peri-operative and post-operative fractures and most importantly, owing to the success of tapered fluted modular stems. In centers such as Exeter where the technique was popularised, it is rarely performed today as well, as the primary cemented stems used there, rarely require revision.

There is ample experience from around the globe, however, with the technique. Much has been learned about the best size and choice of cancellous graft, force of impaction, surface finish of the cemented stem, importance of stem length, and the limitations and complications of the technique. There are also good histology data that demonstrate successful vascularization and incorporation of the impacted cancellous bone chips and host bone.

Our experience at the clinic was excellent with the technique as reported in CORR in 2003 by M Cabanela. The results at mid-term demonstrated minimal subsidence and good graft incorporation. Six of 54 hips, however, had a post-operative distal femoral fracture requiring ORIF. The use of longer cemented stems may decrease the risk of distal fracture and was subsequently reported by the author after reviewing a case series from Exeter.

Today, I perform this technique once or twice per year. It is an option in the younger patient, where bone restoration is desired. Usually in a Paprosky Type IV femur, where a closed tube can be recreated and the proximal bone is reasonable. If the proximal bone is of poor quality, then I prefer to perform a transfemoral osteotomy, and perform an allograft prosthetic composite instead of impaction grafting, and wrap the proximal bone around the structural allograft. I prefer this technique as I can maintain the soft tissues over the bone and avoid the stripping that would be required to reinforce the bone with struts or mesh. Another indication for its use in the primary setting is in the patient with fibrous dysplasia.

Using an institutional database we have identified over 1000 femoral revisions using extensively porous-coated stems. Using femoral re-revision for any reason as an endpoint, the survivorship is 99 ± 0.8% (95% confidence interval) at 2 years, 97 ± 1.3% at 5 years, 95.6 ± 1.8% at 10 years, and 94.5 ± 2.2% at 15 years. Similar to Moreland and Paprosky, we have identified pre-revision bone stock as a factor affecting femoral fixation. When the cortical damage involved bone more than 10cm below the lesser trochanter, the survivorship, using femoral re-revision for any reason or definite radiographic loosening as an endpoint, was reduced significantly, as compared with femoral revisions with less cortical damage.

In addition to patients with Paprosky Type 3B and 4 femoral defects, there are rare patients with femoral canals smaller than 13.5mm or larger than 26mm that are not well suited to this technique. Eight and 10 inch stems 13.5 or smaller should be used with caution if there is no proximal bone support for fear of breaking. Patients with canals larger than 18mm may be better suited for a titanium tapered stem with flutes. While a monolithic stem is slightly more difficult for a surgeon to insert than a modular femoral stem there is little worry about taper junction failure.

The goals of revision total hip on the femoral side are to achieve long term stable fixation, improve quality of life and minimise complications such as intra-operative fracture or dislocation. Ideally these stems will preserve or restore bone stock. Modular titanium stems were first introduced in North America around 2000. They gained popularity as an option for treating Paprosky 3B and 4 defects.

Several studies at our institution have compared the modular titanium stems with monoblock cobalt chromium stems. The main outcomes of interest were quality of life. We also looked at complications such as intra-operative fracture and post-operative dislocation. We also compared these 2 stems with respect to restoration or preservation of bone stock. In 2 studies we showed that modular titanium stems gave superior functional outcomes as well as decreased complications compared to a match cohort of monoblock cobalt chromium stems.

As mentioned one of the initial reasons for introduction of these stems was to address larger femoral defects where failure rates with monoblock cobalt chromium stems were unacceptably high. We followed a group of 65 patients at 5–10 years post-revision with a modular fluted titanium stem. Excellent fixation was obtained with no cases of aseptic loosening. However, there were 5 cases of fracture of the modular junction.

Due to concerns of fracture of the modular junction more recently at our institution we have switched to almost 100% monoblock fluted titanium stems. We recently reviewed our first 100 cases of femoral revision with monoblock stem. Excellent fixation was achieved with no cases of aseptic loosening. Quality of life outcomes were similar to our previous reported series on modular tapered titanium stems.

Both monoblock and modular fluted titanium stems can give excellent fixation and excellent functional outcomes. This leaves a choice for the surgeon. For the low volume revision surgeon modular tapered stems are probably the right choice.

Higher volume surgeons or surgeons very comfortable with performing femoral revision may want to consider monoblock stems. If one is making the switch it would be easiest to start with a simple case. Such a case would be one that can be done with an endofemoral approach. In this the greater trochanter is available as the key landmark for reaming. After the surgeon is comfortable with this stem more complex cases can easily be handled with the monoblock stem.

In summary, both modular and monoblock titanium stems are excellent options for femoral revision. As one becomes more familiar with the monoblock stem it can easily become your workhorse for femoral revision. At our institution we introduced a monoblock titanium stem in 2011. It started out at 50% of cases and now it is virtually used in almost 100% of revision cases.

Using the Mayo Clinic definition (>62mm in women and >66mm in men), the “jumbo acetabular component” is the most successful method for acetabular revisions now, even in hips with severe bone loss. There are numerous advantages: surface contact is maximised; weight-bearing is distributed over a large area of the pelvis; the need for bone grafting is reduced; and usually, hip center of rotation is restored. The possible disadvantages of jumbo cups include: may not restore bone stock; may ream away posterior column or wall; screw fixation required; the possibility of limited bone ingrowth and late failure; and a high rate of dislocation due to acetabular size:femoral head ratio.

The techniques for a successful jumbo revision acetabular component involve: sizing-“reaming” of the acetabulum, careful impaction to achieve a “press-fit”, and multiple screw fixation. We recommend placement of an ischial screw in addition to dome and posterior column screw fixation. Cancellous allograft is used for any cavitary defects. The contra-indications for a jumbo acetabular cup are: pelvic dissociation; inability to get a rim fit; and inability to get screw fixation. If stability cannot be achieved with the jumbo cup alone, then use of augment(s), bulk allograft, or cup-cage construct should be considered.

Using titanium fiber-metal mesh components, we reported the 15-year survival of 129 revisions. There was 3% revision for deep infection and only 3% revision for aseptic loosening. There were 13 reoperations for other reasons: wear, lysis, dislocation, femoral loosening, and femoral fracture fixation. The survival was 97.3% at 10 years, but it dropped to 82.8% at 15 years. Late loosening of this fiber metal mesh component is likely related to polyethylene wear and loss of fixation. Dislocation is the most common complication of jumbo acetabular revisions, approximately 10%, and these are multifactorial in etiology and often require revision. Based on our experience, we now recommend use of an acetabular component with an enhanced porous coating (tantalum), highly crosslinked polyethylene, and large femoral heads or dual mobility for all jumbo revisions.

Most acetabular defects can be treated with a cementless acetabular cup and screw fixation. However, larger defects with segmental bone loss and discontinuity often require reconstruction with augments, a cup-cage, or triflange component – which is a custom-made implant that has iliac, ischial, and pubic flanges to fit the outer table of the pelvis. The iliac flange fits on the ilium extending above the acetabulum. The ischial and pubic flanges are smaller than the iliac flange and usually permit screw fixation into the ischium and pubis. The custom triflange is designed based on a pre-operative CT scan of the pelvis with metal artifact reduction, which is used to generate a three-dimensional image of the pelvis and triflange component. The design of the triflange involves both the manufacturing engineer and surgeon to determine the most appropriate overall implant shape, screw fixation pattern, and cup location and orientation.

A plastic model of the pelvis, and triflange implant can be made in addition to the triflange component to be implanted, in order to assist the surgeon during planning and placement of the final implant in the operating room. A wide surgical exposure is needed including identification of the sciatic nerve. Proximal dissection of the abductors above the sciatic notch to position the iliac flange can risk denervation of the abductor mechanism. Blood loss during this procedure can be excessive.

Implant survivorship of 88 to 100% at 53-month follow-up has been reported. However, in a series of 19 patients with Paprosky type 3 defects, only 65% were considered successful. The custom triflange also tends to lateralise the hip center which may adversely affect hip mechanics. The use of a triflange component is indicated in cases with massive bone loss or discontinuity in which other reconstructive options are not considered suitable.

Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented porous ingrowth components can be used for reconstruction of the vast majority of revision cases, where smaller segmental or cavitary defects are typically present. But when stable structural support on host bone is lacking, highly porous metal acetabular augments have been described as an alternative to large structural allograft. The fundamental concept behind these acetabular augments is the provision of critical additional fixation, structural support and increased contact area against host bone over the weeks following surgery while the desired ingrowth into porous implant surfaces is occurring.

Three separate patterns of augment placement have been utilised in our practice since the development of these implants a decade ago: Type 1 - augment screwed onto the superolateral acetabular rim in a “flying buttress” configuration for treatment of a segmental rim defect, Type 2 – augment placed superiorly against host and then fixed to the acetabular component adjacent to the cup to fill a mainly elliptical cavitary defect, and Type 3 – augment(s) placed medial to the cup to fill a protrusio type cavitary or combined cavitary segmental defect of the superomedial or medial wall, and allow peripheral cup placement against the still intact acetabular rim. In all cases the acetabular component and augment interface is fixed together with cement, with care to prevent any cement extrusion between any implant and the bone. When possible, we now prefer to place the acetabular component first and fix it provisionally with 2 or more screws, and then place the augments second as this is technically quicker and easier. This order of insertion is only possible in type 1 and a few select type 2 cases. Type 3 cases always require placement of one or more augments first, before cup insertion. Supplemental cancellous bone graft is used routinely, but the need for structural bone is avoided.

From 2000 through 2007, porous tantalum acetabular augments were used very selectively in 85 revision THA procedures out of total of the 1,789 revision hip cases performed at our institution. All cases had associated massive acetabular deficiency precluding stable mechanical support for a cup alone. Fifty-eight hips had complete radiographic and clinical follow at minimum 5 years. The majority of patients had either Paprosky type 3A defects (28/58, 48%) or 3B defects (22/58, 38%). Ten out of 58 had pre-operative pelvic discontinuities. Three separate patterns of augment placement were utilised: Type 1 - augment screwed onto the superolateral acetabular rim (21%), Type 2 – augment fixed to the acetabular component adjacent to the cup to fill a mainly elliptical cavitary defect (34%), and Type 3 – augment(s) placed medial to the cup to fill a protrusio type cavitary or combined cavitary segmental defect of the superomedial medial wall (45%). At 5 years, 2/58 (3%) were revised for aseptic loosening and another 6/58 demonstrated incomplete radiolucencies between the acetabular shell and zone 3. One of the revised cups and 5 of 6 of the cups with radiolucencies had an associated pelvic discontinuity.

Highly porous metal acetabular augments are an infrequently needed, but extremely valuable, versatile and reliable adjunctive fixation method for use with uncemented acetabular components during complex revision THA associated with major bone deficiency. Smaller patients are more likely to require this approach as reaming away defects to allow insertion of a jumbo cup is more difficult with a smaller AP dimension to the acetabular columns and less local bone for implant support. Intermediate term durability and apparent radiographic incorporation has been very good despite the complex reconstructions originally required. This technique can allow the avoidance of structural bone grafting for even the most massive of bone defect problems, but additional followup is needed to see how durable these encouraging results are over the longer term.

The treatment of extensive bone loss and massive acetabular defects is a challenging procedure, especially the concomitant pelvic discontinuity (PD) can be compounded by several challenges and pitfalls. The appropriate treatment strategy is to restore a stable continuity between the ischium and the ilium and to reconstruct the anatomical hip center. Antiprotrusio cages, metal augments, reconstruction cages with screw fixation, structural allograft with plating, jumbo cups, oblong cups and custom-made triflange acetabular components have been reported as possible treatment options. Nevertheless, the survivorship following acetabular revision with extensive bone loss is still unsatisfactory. The innovation of three-dimensional printing (3DP) has become already revolutionary in engineering and product design. Nowadays, the technology is becoming part of surgical practice and suitable for the production of precise and bespoke implants. The technique of a 3D-printed custom acetabular component in the management of extensive acetabular defect is presented.

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique.

At our center we use three types of cage constructs –

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Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture, This reconstruction is used in young patients where restoration of bone stock is important.

In our center the cup-cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity.

Acetabular bone loss and presence of pelvic discontinuity were assessed according to the Gross classification. Sixty-seven cup-cage procedures with an average follow-up of 74 months (range, 24–135 months; SD, 34.3) months were identified; 26 of 67 (39%) were Gross Type IV and 41 of 67 (61%) were Gross Type V (pelvic discontinuity). Failure was defined as revision surgery for any cause, including infection.

The 5-year Kaplan-Meier survival rate with revision for any cause representing failure was 93% (95% confidence interval, 83.1–97.4), and the 10-year survival rate was 85% (95% CI, 67.2–93.8). The Merle d'Aubigné-Postel score improved significantly from a mean of 6 pre-operatively to 13 post-operatively (p < 0.001). Four cup-cage constructs had non-progressive radiological migration of the ischial flange and they remain stable.

The moderator will lead a structured panel discussion that explores how to manage challenges commonly found in the multiply revised hip. Topics covered will include: (1) Preferred exposure in multiply operated hip (when to use ETO, when not to use ETO, which type of ETO to use); (2) Implant removal: technical tips for cup removal; (3) Bone loss: favored acetabular reconstruction in severe bone loss (when to use cancellous graft, bulk graft, metal augments); favored acetabular reconstruction methods for different categories of bone loss; favored femoral reconstruction methods for the multiply operated hip; (4) Favored methods of preventing/managing hip instability (large head, dual mobility, constrained implants) in multiply operated hip; (5) When to accept resection arthroplasty as definitive procedure.

The indications for cementless acetabular fixation have been broadened because our data supports the use of trabecular metal cups even when there's limited bleeding host bone contact. Trabecular metal augments have allowed us to use cementless cups when there is segmental loss of bone.

Surgical Technique: The acetabular bed is prepared. If there is less medial bone stock than 2mm, then morselised allograft is impacted by reverse reaming. When reaming is complete and less than 50% bleeding host bone is available for cup stabilisation, then a trabecular metal cup is indicated.

Trabecular augments are used if the trabecular cup trial is not stable, or if it is uncovered by 40% or more. The conventional augments come in different sizes to accommodate the diameter of the cup and the size of the defect. Larger defects are addressed with anterior and posterior column augments, and superior defects with figure of seven augments. Augments are fixed with at least two screws. The interface between the cup and the augments should be stable, but some surgeons place a very thin layer of cement between the augment and cup so micromotion does not occur while ingrowth is occurring.

We have used trabecular metal augments in 46 acetabular revisions in conjunction with a trabecular metal cup. Thirty-four cases have at least 2 years follow-up with an average of 64.5 months. There have been 4 cup loosenings with 3 re-revisions.

The extended proximal femoral osteotomy has been used primarily in conjunction with cementless fixation, but has been described for use with cemented stems as well. The extended proximal femoral osteotomy is indicated for the removal of well-fixed cemented and cementless implants, as well as removal of cement in patients with a loose femoral component in a well-fixed cement mantle. Although the osteotomy is not required for many femoral revisions, it is an absolute indication in patients with femoral component loosening and subsequent varus remodeling of the proximal femur.

The osteotomy diminishes the risk of an inadvertent fracture of the often compromised greater trochanter especially upon removal of a failed femoral component from its subsided or migrated position. The osteotomy enhances the exposure of the acetabulum which may be difficult in the revision setting due to multiple surgeries, severe migration of the acetabular component or the heterotopic ossification.

The extended proximal femoral osteotomy can also be used in the primary setting when a proximal femoral deformity interferes with straight reaming of the femoral canal, such as in patients with various dysplasias, previous corrective osteotomies or malunions.

Revision total hip arthroplasty (THA) is a challenging procedure, especially in cases with well-fixed implants. In such cases, several removal techniques have been presented in the current literature, while the most commonly used techniques are the transfemoral osteotomy or the extended trochanteric osteotomy (ETO). Those techniques allow the surgeon to have a better intra-operative exposure of the fixation surfaces of the solid femoral stems. However, the complication rates such as non-union are not unremarkable. Therefore, it is always a good decision to avoid an ETO if alternative techniques exist. The endofemoral surgical technique is an alternative method for the removal of well-fixed cemented and uncemented femoral stems.

There are several clinical scenarios to consider cementing an acetabular liner into a secure cementless shell including cases of: 1) inadequate capturing mechanism, 2) damaged locking mechanisms, 3) unavailability of the mating polyethylene liner, 4) instability following debridement for wear, 5) instability at the time of femoral side revision, and 6) recurrent dislocation. The last two situations are common scenarios for cementing a constrained liner into a secure shell.

Technique includes: 1) scoring the shell in cases with no screw holes or polished inner shells, 2) scoring the acetabular liner in a “spider web” pattern, 3) pressurizing cement into the shell, and 4) inserting a liner that allows 2mm of cement mantle.

Results of Cementing Constrained Liner Into Secure Cementless Shell: Callaghan et al. JBJS 2004. Thirty-one hips at 2–10 year follow-up. Two of 31 failed. Technical considerations: do not cement proud and do not cement into a malpositioned shell; Haft et al. J Arthroplasty 2002. Seventeen hips with minimum 1 year follow-up. One of 17 failed. Technical considerations: do not cement proud.

Results of Cementing Non-Constrained Liners Into Secure Cementless Shell: Beaule et al. JBJS 2004. Thirty-two hips at mean 5.1 year avg f/u. Four components revised for loosening; Callaghan et al. CORR 2012. Thirty-one hips at mean 5.3 year f/u. No revisions.

Improvements in ceramic materials, component design, and surgical technique have made ceramic bearing complications increasingly rare. However, when it happens, a fractured ceramic component can cause significant pain and morbidity following total hip arthroplasty (THA). The hard and sharp particulate debris from fractured ceramic components can cause damage to the existing hip prosthesis and jeopardise subsequent revision THA results due to third body wear.

Patients with ceramic fractures can present with sudden onset of pain and dysfunction. Often, the patient will report a noisy hip articulation. Radiographs can range from subtle densities surrounding the hip implant to complete disintegration and loss of sphericity of the femoral head or acetabular liner.

Ceramic component fractures should be treated expeditiously. Revision options for failed ceramic components depend on existing component fixation, position, and locking mechanism and femoral trunnion integrity. In order to retain the implants, the components must be well-fixed, in good position, and have tapers and locking mechanisms that can accept new modular components. Additionally, an extensile exposure and complete synovectomy are necessary to remove as much of the sharp particulate debris. Finally, a new ceramic ball head with a titanium inner sleeve should be used in revisions for fractured ceramics due to their hardness and scratch resistance.

Early results for revision surgery for fractured ceramic components were inconsistent. Allain et al. reported on a series of 105 revisions performed for ceramic head fractures and found that the survivorship at 5 years was only 63%. The authors reported a high reoperation rate and also worse survivorship when the acetabular component was retained, a metal head was used for revisions, age younger than 50 years, and when a complete synovectomy was not performed at the time of revision. More recently, Sharma and colleagues reported on a series of 8 ceramic fractures revised to a metal-on-polyethylene articulation performed with a complete synovectomy. At 10-year follow-up, the authors reported on failures; increased wear; or lesser function compared to 6 matched patients undergoing revision using similar implants for other diagnoses. Others have also reported catastrophic failures when revising fractured ceramic components using metal ball heads.

In summary, ceramic bearing complications in THA are rare but catastrophic events. A systematic approach to evaluation and management is necessary to ensure a safe return.

Abductor deficiency after THA can result from proximal femoral bone loss, trochanteric avulsion, muscle destruction associated with infection, pseudotumor, ALTR to metal debris, or other causes. Constrained acetabular components are indicated to control instability after THA with deficient abductors. However, the added implant constraint also results in greater stresses at the modular liner-locking mechanism of the constrained component and bone-implant fixation interface, which can contribute to mechanical failure of the constrained implant or mechanical loosening.

Use of large heads has been effective in reducing the rate of dislocation after primary THA. However, relatively large (36mm) heads were not found to be effective in controlling dislocation in patients with abductor deficiency. Dual mobility implants which can provide considerably larger head diameters than 36mm may offer an advantage in improving stability in patients with abductor deficiency. However the utility of these devices in controlling instability after THA with deficient abductors has not been established.

Whiteside has described a transfer of the tensor muscle and anterior gluteus maximus to the greater trochanter for treatment of absent abductors after THA. Transposition of the tensor muscle requires raising an anterior soft tissue flap to the lever of the interval between the tensor muscle and sartorius, which is the same interval used in an anterior approach to the hip. The muscle is transected distally and transposed posteriorly to attach to the proximal femur. This can result in soft tissue redundancy between the posterior tensor muscle and anterior gluteus maximus. This interval is separated and the anterior gluteus maximus also attached to the proximal femur. The transposed tensor muscle provides muscle coverage over the greater trochanter, which may be beneficial in controlling lateral hip pain.

In our practice, 11 patients were treated with Whiteside's tensor muscle transfer. Six patients had absent abductors, one had an avulsed greater trochanter, and four intact but weak abductors. One patient had a muscle transposition alone, one had an ORIF of the greater trochanter and muscle transposition, two had a muscle transposition and head/liner exchange, three had a muscle transposition and cup revision, two had a femoral revision and liner exchange with muscle transposition, and two had a muscle transposition with both component revision. None of the patients had constrained components.

The mean pre-operative abductor strength was 2.2 (0/5 in four patients 3/5 in four patients, and 4/5 in three patients). Pre-operative lateral hip pain was none or mild in two patients, moderate in three, and severe in six patients. Mean post-operative abductor strength was 3.2 (2/5 in four patients, 3/5 in three, 4/5 in two, 5/5 in two patients). Post-operative lateral hip pain was none in five and mild in six patients. One patient sustained a dislocation four weeks after surgery which was treated with open reduction. All of the other hips have remained stable.

Treatment of patients with hip instability and abductor deficiency has generally required use of a constrained acetabular component. In our experience, transfer of the tensor muscle and anterior gluteus maximus to the greater trochanter can improve abductor strength by one grade and also reduce lateral hip pain. The combination of a large head and tensor muscle transposition may be a viable alternative to use of a fully constrained component in patients with deficient abductors after THA. However, the need for implant constraint should also be individualised and based on factors such as the viability of the transposed muscle, patient compliance with post-operative activity restrictions, femoral head/neck ratio, and cup position.

The main challenges in hip arthrodesis takedown include the decision to perform fusion takedown and the technical difficulties of doing so. In addition to the functional disadvantages of hip fusion, the long-term effects of hip arthrodesis include low back pain and in some cases ipsilateral knee pain. Indications for fusion conversion to THA include arthrodesis malposition, pseudoarthrosis, and ipsilateral knee, low back, contralateral hip problems, and functional disadvantages of ipsilateral hip fusion. When deciding whether or not to take down a fusion, consider the severity of the current problem, risks of takedown and likely benefits of takedown. Best results of fusion takedown occur if abductor function is likely to be present. If the abductors are not likely to function well, dearthrodesis may still help, but the patient will have a profound Trendelenburg or Duchenne gait and risk of hip instability will be higher. Abductor assessment can be performed by determining if the abductors contract on physical exam and determining if the previous form of fusion spared the abductors and greater trochanter. EMG and MRI also can be performed to assess the abductors, but value in this setting is unproven. Before dearthrodesis establish realistic expectations: most patients will gain hip motion—but not normal motion, most will see improvement in back/knee pain, but many will become cane-dependent for life.

The main technical issues to overcome involve exposure, femoral neck osteotomy, acetabular preparation, and femoral fixation. Exposure can be conventional posterior, anterolateral or direct anterior with an in situ femoral neck cut. In complex cases, a transtrochanteric approach is often helpful. The in situ neck cut is facilitated by fluoroscopy or intra-operative radiograph to make sure the cut is at the correct level and at the correct angle. Be careful not to angle into the pelvis with the cut. Acetabular preparation is more complex because anatomic landmarks often are absent or distorted. Try to find landmarks including ischium, ilium, teardrop, and fovea. Confirm location with fluoroscopy as reaming commences and during reaming. Depth of reaming can be improved by using the fovea (if present) and teardrop on fluoroscopy. Cup fixation is usually an uncemented cup, fixed with multiple screws because bone quality typically is compromised. Femoral fixation is at the surgeon's discretion, recognizing the proximal bone may be distorted in some cases. Post-operative management includes protected weight bearing as needed and heterotopic bone prophylaxis in selected patients.

Acetabular implant position is important for the stability, function, and long-term wear properties of a total hip arthroplasty (THA). Prior studies of acetabular implant positioning have demonstrated a high percentage of outliers, even for experienced hip surgeons, when conventional instruments are used.

Computer navigation is an attractive tool for use in THA, as it has been shown to improve the precision of acetabular component placement and reduce the incidence of outliers. However, computer navigation with imageless, large-console systems is costly and often interrupts the surgeon's workflow, and thus has not been widely adopted.

Another method to improve acetabular component positioning during THA is the use of fluoroscopy with the direct anterior approach. Studies have demonstrated that the supine position of the patient during surgery facilitates the use of fluoroscopic guidance, thus improving acetabular component position.

A handheld, accelerometer based navigation unit for use in total hip replacement has recently become available to assist the surgeon in positioning the acetabular component during anterior approach THA, potentially reducing the need for intra-operative fluoroscopic studies. We sought to compare the radiographic results of direct anterior THA performed with conventional instrumentation vs. handheld navigation to determine the accuracy of the navigation unit, and to see whether or not there was a reduction in the fluoroscopic time used during surgery. Furthermore, we timed the use of the navigation unit to see whether or not it required a substantial addition to surgical time.

Our results demonstrate that a handheld navigation unit used during anterior approach THA had no difference with regard to acetabular cup positioning when compared to fluoroscopically assisted THA, but led to a reduction in the use of intra-operative fluoroscopy time.

Excellent outcomes following total hip arthroplasty require both optimal soft-tissue management and precise planning and placement of prosthetic components. The use of detailed and dynamic three-dimensional surgical plans combined with smart mechanical instruments for component placement facilitates precise and efficient surgery. Interest in these technologies has increased recently as surgeons and institutions are now responsible for poor outcomes in a growing percentage of the patient population.

Cloud-based, patient-specific planning allows the surgeon to review and refine and execute surgical plans efficiently (HipXpert System, Surgical Planning Associates, Boston, MA). The surgical plans include cup size, cup orientation, stem size, head length, femoral anteversion, and planned change in leg length and offset, all in relation to the patients bony anatomy in 3D and multiplanar views. The associated smart tool is adjusted specifically for that patient and when docked, provides orientation information to the surgeon.

The system has been proven to be robust, with repeated studies showing accurate cup placement in 100% of cases including by an independent study. This compares to a recent study of robotic methods that 88% of inclination and 84% for anteversion and to even greater inaccuracy of conventional surgery.

Cloud-based 3D planning combined with smart mechanical navigation of cup placement offers the optimum combination of accuracy, speed, and simplicity for solving the ubiquitous problems of component sizing, orientation, and version, offset, and leg length correction. Knowledge of component sizing pre-operatively can facility inventory management and allows the surgery team to better anticipate the surgeon's goals during the procedure.

In North America, cementless femoral replacement has all but replaced cementing and cement technique is at risk for becoming a lost art. Published results of cemented femoral components with a well-designed femoral component and good surgical technique are excellent and equivalent to cementless technology. With an increasing focus on cost as part of value-based care, consideration for returning to cement for a select population is appropriate. Furthermore, there are patient populations that may benefit from a cemented femur with registries demonstrating superior short term outcomes. These include the elderly and patients with osteoporotic femurs.

The goal of femoral cementing is to maximise the interdigitation of bone cement with metaphyseal trabecular bone and the irregular surface of the endosteum while at the same time minimizing the risk of embolization.

The steps for femoral cementing include:cFemoral broaching – understand the relationship between the broach and stem as it relates to cement mantle thickness; Canal preparation; Gentle curetting to remove loose cancellous bone; Pressurised lavage to remove fat and marrow elements – this decreases the risk of embolization and enhances the strength of the bone-cement interface; Dry the canal – suction, adrenaline soaked sponge – this minimises bleeding and enhances the strength of the bone cement interface; Cement preparation – vacuum mix or centrifuge the bone cement – this minimise large voids that weaken the bone cement; Cement insertion – insert in a retrograde fashion and pressurise the cement – this optimises the cement column and the bone cement interface; Stem insertion – insert slowly with a system that centralises the stem – this prevents mantle defects that have been associated with stem loosening.