Papers to be discussed during this session include: Surgical approach and THA results - does it matter?; Minimizing infection in TJA - doing all you can….; I&D or Revision, 1 vs. 2 stage for infected TKA - now or later?; Barbed sutures - friend or foe?; Constraint in TKA - promises and pitfalls!; Tendonitis after THA - minimizing the pain; MRI after THA - when and why…….; Pain, opioids, and outcomes - sorting fact from fictions!; Outpatient TKA - home free?; TKA in general - does home matter?; Drainage after TKA - mopping up the mess!; Head size in THA - does it matter, help or hurt?; Hip bone connected to the spine bone - so what!; Tourniquet in TKA - does it make a difference?; Standardise or personalise? - that is the question!; Trusting the robot - really?; The TKA - rotation, rotation, rotation.

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.

Down syndrome (DS), is a genetic disorder caused by a third copy of the 21st chromosome (Trisomy 21), featuring typical facial characteristics, growth delays and varying degrees of intellectual disability. Some degree of immune deficiency is variably present. Multiple orthopaedic conditions are associated, including stunted growth (90%), ligamentous laxity (90%), low muscle tone (80%), hand and foot deformities (60%), hip instability (30%), and spinal abnormalities including atlanto-axial instability (20%) and scoliosis.

Hip disease severity varies and follows a variable time course. Rarely a child presents with DDH, but during the first 2 years the hips are characteristically stable but hypermobile with well-formed acetabulae. Spontaneous subluxation or dislocation after 2 presents with painless clicking, limping or giving way. Acute dislocation is associated with moderate pain, increased limp and reduced activity following minor trauma. Hips are reducible under anesthesia, but recurrence is common. Eventually concentric reduction becomes rarer and radiographic dysplasia develops. Pathology includes: a thin, weak fibrous capsule, moderate to severe femoral neck anteversion and a posterior superior acetabular rim deficiency. A number of femoral and acetabular osteotomies have been reported to treat the dysplasia, with acetabular redirection appearing to be most successful. However, surgery can be associated with a relatively high infection rate (20%). Additionally, symptomatic femoral head avascular necrosis can occur as a result of slipped capital femoral epiphysis.

Untreated dysplasia patients can walk with a limp and little pain into the early twenties even with fixed dislocation. Pain and decreasing hip function is commonly seen as the patient enters adult life. Occasionally the hip instability begins after skeletal maturity. Total hip arthroplasty (THA) is the standard treatment when sufficient symptoms have developed. The clinical outcomes of 42 THAs in patients with Down syndrome were all successfully treated with standard components. The use of constrained liners to treat intra-operative instability occurred in eight hips and survival rates were noted between 81% and 100% at a mean follow-up of 105 months (6 – 292 months).

A more recent study of 241 patients with Down syndrome and a matched 723-patient cohort from the Nationwide Inpatient Sample compared the incidence of peri-operative medical and surgical complications in those who underwent THA. Compared to matched controls, Down syndrome patients had an increased risk of complications: peri-operative (OR, 4.33; P<.001), medical (UTI & Pneumonia OR, 4.59; P<.001) and surgical (bleeding OR, 3.51; P<.001), Mean LOS was 26% longer (P<.001).

While these patients can be challenging to treat, excellent surgical technique and selective use of acetabular constraint can reliably provide patients with excellent pain-relief and improved function. Pre-operative education of all clinical decision makers should also reinforce the increased risk of medical and surgical complications (wound hemorrhage), and lengths of stay compared to the general population.

Nutritional Status and Short-Term Outcomes Following THA; Initial Metal Ion Levels Predict Risk in MoM THA; THA Bearing Surface Trends in the US ‘07- ’14; Dislocation Following Two-Stage Revision THA; Timing of Primary THA Prior to or After Lumbar Spine Fusion; Failure Rate of Failed Constrained Liner Revision; ESR and CRP vs. Reinfection Risk in Two-Stage Revision?; Mechanical Complications of THA Based on Approach; Impaction Force and Taper-Trunnion Stability in THA; TKA in Patients Less Than 50 Years of Age; Post-operative Mechanical Axis and 20-year TKA Survival and Function; Return to Moderate to High-intensity Sports after UKA; “Running Two Rooms” and Patient Safety in TJA; Varus and Implant Migration and Contact Kinematics after TKA; Quadriceps Snips in 321 Revision TKAs; Tubercle Proximalization for Patella Infera in Revision TKA; Anterior Condylar Height and Flexion in TKA; Compression Bandage Following Primary TKA; Unsupervised Exercise vs. Traditional PT After Primary TKA and UKA.

Total Knee Arthroplasty (TKA) necessitates disruption of well vascularised tissue during exposure and soft tissue release as well as from the cutting of bone, and thus bleeding into the joint space routinely occurs to some degree following TKA. Defining a complication from bleeding is not necessarily straightforward, but includes 3 different conditions: hemarthrosis, hematoma, and bloody wound drainage. All of these conditions can be seen in the normal post-operative setting, and when mild may be simply observed. However, persistent swelling resulting in clinical symptoms should be appropriately treated.

A hemarthrosis is defined as blood being contained in the knee capsule. Although some bleeding is expected, “excessive” hemarthrosis results in increased pain limiting or difficulty regaining motion. If high levels of fluid pressure are present, rupture of the arthrotomy may occur. A hematoma occurs when intra-articular blood escapes the arthrotomy and drains into the overlying soft tissues. This may occur following performance of a large lateral release or an insufficient arthrotomy closure or simply secondary to a large hemarthrosis under tension. Symptoms include ecchymosis, soft tissue swelling, and potential skin complications. Increased pain and limited range of motion frequently accompany these symptoms. Wound drainage may present as a knee that continues to have bloody or serous drainage that continues long after the first or second dressing change. It is this continued wound drainage that is most worrisome with increased wound infection rates when prolonged drainage is allowed to persist.

The incidence of post-operative hemarthrosis as a clinical problem is not well studied, but the need for surgical treatment is uncommon. Recurrent hemarthrosis is also relatively rare after total knee arthroplasty and has been reported at rates between 0.3% and 1.6%. The etiology of this complication can be systemic or local, and initial work-up should include coagulation studies to rule out any underling systemic coagulopathy. Conservative therapy including rest, cooling, and elevation is the preferred treatment for mild cases. If conservative treatment is not successful, or the acute hemarthrosis is clinically tense, interfering with recovery, or threatening wound healing, drainage may be the preferable option. This can be done by opening the arthrotomy in the operating room or through a large bore arthroscopy cannulae. Careful attention to debridement of clotted blood must be followed by a meticulous search for potential sources of bleeding which should be managed appropriately.

Recurrent hemarthrosis may occur at any time after surgery. Repeated bleeding episodes may lead to an inflammatory cascade that propagates bleeding events more readily. If coagulation studies are normal, the most common source is the impingement of proliferative synovium or other retained soft tissue between the articulating components of the knee prosthesis. Other causes include damage to the geniculate or popliteal vessels with pseudo aneurysm formation. Mild to moderate clinical knee instability may be associated with bloody synovial effusions but limited clinical complaint specific to instability. Other causes may be multifactorial and synergistic but are not well understood, making diagnosis and treatment more difficult. If symptoms persist, and the resulting disability is sufficient, classical treatment has consisted of open or arthroscopic synovectomy. Over the past decade angiography and angiographic embolization of the source of bleeding has been shown to be successful. Radio-active synovectomy has also been successful.

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.

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

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.

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.

As the incidence of total hip arthroplasty (THA) rises, an increasing prevalence of peri-prosthetic femur fractures has been reported. This is likely due to the growing population with arthroplasties, increasing patient survival and a more active life-style following arthroplasty. It is the 3rd most common reason for THA reoperation (9.5%) and 5th most common reason for revision (5% with fracture risk after primary THA reported at 0.4%-1.1% and after revision at 2.1%-4%).

High quality radiographs are usually sufficient to classify the fracture and plan treatment. Important issues in treatment include stem fixation status and fracture location relative to the stem. Additional comorbidities will also influence treatment choices, of which the most critical is the presence of infection and the quality of bone stock.

The most commonly studied, and reported classification system is the Vancouver. Type A are peri-trochanteric fractures with AL at the lesser and AG at the greater trochanter. B fractures are those around the stem with B1 fractures having a well-fixed stem, B2 a loose stem with adequate bone stock, and B3 representing loose stem and inadequate bone stock. C fractures are distal to the stem.

Type A) Trochanteric Fractures: These are usually associated with lysis. Displaced fractures can be managed adequately with cerclage fixation and cancellous allograft to fill osteolytic defects. Undisplaced fractures usually heal well with symptomatic treatment.

Type B) Fractures Around the Stem: The B1 type has a well-fixed component and is usually treated with extramedullary fixation plus graft. Contemporary plates have been designed specifically for these fractures. Strut allograft may be used to provide a more rigid construct. Spiral and long oblique fractures can be cerclaged while short oblique or transverse fractures require fixation anterior and lateral with cable plates and cortical strut grafts. Screws can be used distal to the implant, and cables used proximally. The B2 type has a loose prosthesis but otherwise good bone stock. In this setting, the fracture line may be extended on the lateral cortex of the femur as an extended osteotomy to provide easy access for cement removal. These fractures can be managed with an extensively coated stem if rotational stability can be obtained in the distal segment. If rotational stability over a 4 cm scratch interference fit of the stem isn't possible, then a fluted tapered modular stem should be used. Strut allografts improve initial stability. The B3 type has both a loose prosthesis and poor bone stock and in the younger patient restoration of bone stock should be a priority. Bulk femoral grafts may be needed. The elderly or low functional demand patient may be treated with a proximal femoral replacement. Because of soft-tissue deficiencies, a constrained acetabular liner may be needed to prevent instability.

Type C) Fractures Distal to the Stem: These usually accompany a stable stem and many fixation devices are available. Locking plates have become most popular and should be secured with cerclage wires proximally around the component with screws distally. Retrograde nails may be employed if there is adequate bone distal to the stem tip and above the fracture.

Effectiveness of Liposomal Bupivacaine for Post-Operative Pain Control in Total Knee Arthroplasty: A Prospective, Randomised, Double Blind, Controlled Study

Pericapsular Injection with Free Ropivacaine Provides Equivalent Post-Operative Analgesia as Liposomal Bupivacaine following Unicompartmental Knee Arthroplasty

Total Knee Arthroplasty in the 21st Century: Why Do They Fail? A Fifteen-Year Analysis of 11,135 Knees

Cryoneurolysis for Temporary Relief of Pain in Knee Osteoarthritis: A Multi-Center, Prospective, Double-Blind, Randomised, Controlled Trial

Pre-Operative Freezing of Sensory Nerves for Post-TKA Pain: Preliminary Results from a Prospective, Randomised, Double-Blind Controlled Trial

Proximalization of the Tibial Tubercle Osteotomy: A Solution for Patella Infera during Revision Total Knee Arthroplasty

Treatment of Periprosthetic Joint Infection Based on Species of Infecting Organism: A Decision Analysis

Alpha-Defensin Test for Diagnosis of PJI in the Setting of Failed Metal-on-Metal Bearings or Corrosion

Risk of Reinfection after Irrigation and Debridement for Treatment of Acute Periprosthetic Joint Infection following TKA

Serum Metal Levels for the Diagnosis of Adverse Local Tissue Reaction Secondary to Corrosion in Metal-on-Polyethylene Bearing Total Hip Arthroplasty

Intra-Articular Injection for Painful Hip OA - A Randomised, Double-Blinded Study

Six-Year Follow-up of Hip Decompression with Concentrated Bone Marrow Aspirate to Treat Femoral Head Osteonecrosis

No Benefit of Computer-Assisted TKA: 10-Year Results of a Prospective Randomised Study

Background

Heterotopic ossification (HO) is a known complication following total hip arthroplasty, with increased incidence in certain patient populations. Current prophylaxis options include oral non-steroidal anti-inflammatory drugs (NSAIDs) and radiation therapy, but an optimal radiation protocol has yet to be clearly defined. We performed a randomized, double-blinded clinical trial in high-risk total hip arthroplasty patients to determine the efficacy of 400 cGy versus 700 cGy doses of radiation.

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.

Acetabular fracture treatment outcomes have improved over the past two decades due to the more accurate identification of common fracture patterns, the development of more adequate surgical approaches, and the creation of improved methods for reduction and repair. However, certain cases have a distinctly lower likelihood of a favorable outcome, and in this setting primary arthroplasty as part of the open reduction and internal fixation (ORIF) may provide the best solution. Acute primary total hip arthroplasty (THA) provides primary stability and immediate pain relief, permits graded weight-bearing and early pain-free mobilization, and may also treat pre-existing hip arthritis. Removal of the femoral head improves exposure making fracture reduction and fixation easier without the need for more extensile approaches. Open reduction and internal fixation to obtain stability of the anterior and posterior columns is followed by placement of a multi-holed acetabular shell which serves as a supplementary internal fixation device. The femoral head can be used as bulk bone graft to replace and reinforce the reconstruction. These complex procedures are best undertaken by a surgical team with substantial experience with both acetabular trauma and hip arthroplasty.

Despite improvements in outcomes with ORIF, THA is commonly required following failed treatment. Scarring, heterotopic ossification, bone defects, residual deformity, devitalised bone fragments and previous implants can make the procedure challenging. If the patient has undergone previous ORIF it is important to rule out low grade sepsis with appropriate blood tests (ESR + CRP) and further work-up as warranted. Surgical exposure must be carefully planned so as to be able to access all aspects of the acetabulum, including removal of hardware which may interfere with acetabular component placement.

Bone stock loss, malunion and/or non-union must be evaluated with appropriate radiographs or CT scans may be required. Acetabular replacement in the face of deformity from previous trauma encompasses three main problems; bony defects, the presence of bone in places where it is not normally encountered, such as surrounding and incarcerating the femoral head, or substantially anterior or lateral to the center of the acetabulum, and movement of the acetabulum from its normal relationship to the remainder of the pelvis to a new location, such as a higher or more medialised hip center. Intraoperative landmarks may be obscured and therefore placement of reamers and the component may be confusing. THA after acetabular fracture is technically demanding and generally is accompanied by results more typical of revision than primary arthroplasty for degenerative disease.

The following papers will be discussed during this session: 1) Staph Screening and Treatment Prior to Elective TJA; 2) Unfulfilled Expectations Following TJA Procedures; 3) Thigh Pain in Short Stem Cementless Components in THR; 4) Is the Direct Anterior Approach a Risk Factor for Early Failure?; 5) THA Infection - Results of a 2nd 2-Stage Re-implantation - Clinical Trial of Articulating and Static Spacers; 6) THA Revision - Modular vs. Non Modular Fluted Tapered Stems-Total Femoral Replacement for Femoral Bone Loss - Cage + TM Augment vs. Cup Cage for Acetabular Bone Loss; 7) Do Injections Increase the Risk of Infection Prior to TKA?; 8) Long-Acting Opioid Use Predicts Perioperative Complication in TJA; 9) UKA vs. HTO in Patients Under 55 at 5–7 years; 10) Stemming Tibial Component in TKA Patients with a BMI > 30; 11) The Effect of Bariatric Surgery Prior to Total Knee Arthroplasty; 12) Oral Antibiotics and Reinfection Following Two-Stage Exchange; 13) Two-Stage Debridement with Prosthetic Retention for Acute TKA Infections; 14) Patient-Reported Outcomes Predict Meaningful Improvement after TKA; 15) Contemporary Rotating Hinge TKA; 16) Liposomal Bupivacaine in TKA; and 17) Noise Generation in Modern TKA: Incidence and Significance.

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

As prosthetic constraint increases one may need to use intramedullary stems. Their use may be compromised by the deformity. Finally, 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 wedge correction required) the more likely I am to manage the deformity with intra-articular correction and increased TKA constraint.

Metal Ion Levels Not Useful in Failed M-O-M Hips: Systematic Review; Revision of Failed M-O-M THA at a Tertiary Center; Trunnionosis in Metal-on-Poly THA?; Do Ceramic Heads Eliminate Trunnionosis?; Iliopsoas Impingement After 10 THA; Pain in Young, Active Patients Following THA; Pre-operative Injections Increase Peri-prosthetic THA Infection; Debridement and Implant Retention in THA Infection; THA after Prior Lumbar Spinal Fusion; Lumbar Back Surgery Prior to THA Associated with Worse Outcomes; Raising the Joint Line Causes Mid-Flexion Instability in TKA; No Improvement in Outcomes with Kinematic Alignment in TKA; Botox For TKA Flexion Contracture; Intra-operative Synovitis Predicts Worse Outcomes After TKA for OA; When is it Safe for Patients to Drive After Right TKA?; Alpha-Defensin for Peri-prosthetic Joint Infection; Medial Tibia Overhang and Pain Score After TKA

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 they are 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 used 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.

When is revision surgery contraindicated in the face of a failed total hip? Surgically indicated can be interpreted as a situation where the patient will benefit from a specific intervention, with sufficient likelihood, to warrant the risks of intervention. Contraindication connotes the opposite; the risks, or likelihood of the intervention's failure to achieve the desired results outweigh the expected extent and likelihood of benefit. Contraindicated actually represents the end point of a complex decision making process which must be carried out by the practitioner in conjunction with the patient and may require the full range of the surgeons analytical, technical and communication skills. Most commonly the term means that the surgeon's thinking has led to a belief that the patient will be better off without further surgery.

Deciding to forego another revision usually means leaving the patient with a resection arthroplasty. Relative indications for resection, or even avoiding revision of a failed arthroplasty, are most commonly biological. In a healthy host, with a sterile but anatomically deficient bed with adequate soft tissue coverage, mechanical reconstruction capabilities and massive bulk allograft may allow reconstruction of almost any amount of tissue loss. Severe osteomyelitis or soft tissue infection, unmanageable for reasons, including but not limited to: chronic immune-suppression, mixed or resistant organisms or a life threatening sensitivity to antibiotics which may be required to treat the sepsis. More subjective factors, such as adequacy of soft tissue and bone stock, comorbid medical conditions or a patient's desire to avoid additional surgery as well as costs must be considered. This decision may include dozens of other considerations, some of which may be considered pre-operatively and some which may only arise intra-operatively.

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 6–8 weeks of immobilization. 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 prevents a “tension-free” repair. In most chronic disruptions allograft extensor mechanism reconstruction is preferable. 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.

Outcomes of THA after Hip Arthroscopy

Hip Injections and Rapidly Progressing Joint Degeneration

Procedure Duration Wound Complications & LOS

Losing Weight Following TKA and its Influence on Outcome

Radiographic Severity of Arthritis & Patient Satisfaction in TKA

Intra-wound Vancomycin Powder Reduces Infections in TJA

Increased Non-stemmed Tibial Failures with BMI ≥ 35

Influence of Component Alignment on Outcome in Varus TKA

New TKA Designs - Do Patients Notice?

Bariatric Surgery Prior to TKA Associated with Fewer Complication

Metal Sensitivity Correlates with Pain in Patients with TJA

Blood Culture Bottles vs. Swabs for Microbial Detection in PJI

I&D Prior to 2 Stage Revision TKA Doesn't Increase Risk of Failure

Outpatient Total Joint Leads to Substantial Burden of Phone Calls

Wear and lysis of HXL Sockets: Effect of Head Size @ 10–14 Years

Surface Finish & Survivorship of Cemented Stems in THA

Patient Reported Outcome as a Tool for Appropriateness in THA

Neuraxial Anesthesia and Post-op Complications and Transfusions

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

The initial application of bone ingrowth technology to the fixation of total knee arthroplasty (TKA) components without bone cement was based on the premise that bone cement was “not biologic”, and so over time would undergo fatigue failure with subsequent loosening. It was hoped that this problem could be obviated by cementless fixation by bone ingrowth, which would remodel over time and not fatigue. In addition, it was anticipated that the failed cementless TKA might be easier to revise and leave the surgeon with more bone to work with. Whether or not cementless fixation of TKA components was justified on any of these counts was uncertain through the first 2 decades of their use. Much of the data accumulated during that period poorly supported these contentions, while cemented TKA was increasingly reported as a reliable, consistent and less complicated form of TKA fixation. However, over the past decade, new evidence has accumulated demonstrating greater success with this technology in several well designed studies as well as from registry studies. Most of this evidence involves the use of Porous Tantalum. However, increasing evidence that loosening of well done, well designed cemented TKA is rare along with some evidence that a certain percentage of cementless TKA patients fail to achieve stability remains concerning. In addition, no studies have justified improved longevity to the extent that the increased cost of cementless devices can be justified.

Laxity Differences in CR & PS TKA -Achieving Total Knee Balancing Using Bone Cut Adjustments and Correlation with Varus-Valgus Lift-Off

The Incidence and Mid Term Functional Effect of Partial PCL Recession in Fixed and Mobile Bearing PCL Retaining TKA

Clinical and Radiographic Results of a Modern Design, Onlay Patellofemoral Arthroplasty at a Minimum Two-Year Follow-Up

Custom Cutting Guides Do Not Improve Total Knee Arthroplasty Outcomes at 2 Years Follow-up

Tourniquet Use During TKA -Effect on Recovery of Strength and Function: a randomised, double-blind, control trial

Prospective, Randomised Trial of Standard vs Cross-linked Tibial Poly

Crosslink vs. Conventional TKA Poly Retrieval Analysis

Unplanned Readmissions after TKA Using a Statewide Database

Does Prior Cartilage Restoration Negatively Impact Outcomes of TKA

Periprosthetic Femur Fracture: Better to Revise than to Fix

Increased Non-stemmed Tibial Failures in Patients with a BMI ≥ 35

The Effect Of Canal Fit And Fill in Revision THA With Modular, Fluted, Tapered Stems

The Wagner Cone Stem For The Challenging Femur In Primary Total

Will Metal Heads Restore Integrity of Corroded Trunnions at Revision THR?

Influence of Head Size, Materials and Taper Design on Fretting and Corrosion of Metal on Polyethylene THR

Delta Ceramic on Ceramic THA – Midterm IDE Study Results

Refining Acetabular Safe Zone for Posterior Approach in THA

Comparison of a Pain Program for THA with and without Liposome Bupivacaine

General Principles

Repairs should be immobilised in full extension for 6–8 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees.

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 immobilization. Augmentation with a semitendinosus graft can provide additional structural 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 turn-down 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. In most chronic disruptions complete allograft extensor mechanism reconstruction is preferable. If the patella itself has not retracted proximally and remains intact other allograft soft tissues are a viable alternative. All grafts should be repaired tightly with the knee in full extension.

General Principles

Repairs should be immobilised in full extension for 6–8 weeks. Gradual resumption of motion in a hinged brace over an additional 6–8 weeks almost always yields flexion to at least 90 degrees.

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 6–8 weeks of immobilisation. Augmentation with a semitendinosus graft can provide additional structural 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 turn-down 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. In most chronic disruptions complete allograft extensor mechanism reconstruction is preferable. If the patella itself has not retracted proximally and remains intact, other allograft soft tissues are a viable alternative. All grafts should be repaired tightly with the knee in full extension.

Several disadvantages can be attributed to suture knots in wound closure: they are tedious to tie, may be a nidus for infection and can strangulate tissue. They may extrude through skin weeks after surgery. Additional needle manipulations during knot-tying may predispose to glove perforation. A self-anchoring barbed suture has been developed that requires no knots (or slack suture management) for wound closure. The elimination of knot tying has demonstrated some advantages over conventional wound closure methods. It has demonstrated comparable efficacy for the long term closure of C section wounds. The lack of bulk afforded by the knotless suture proves useful in mid face lift applications where knots are a drawback to traditional suture use and cosmesis is of primary importance.

This type of suture has demonstrated improved “water tightness” in knee arthrotomy closure compared to a standard interrupted suture technique in a cadaver model, has demonstrated reduced time for total surgery by 10% and time for closure by 33%. Use of this suture has been shown to be safe and effective in many other surgical specialties, while proving easier and faster than traditional suturing technique. Its use is highly recommended.

Direct Anterior vs Mini-posterior THA with Advanced Pain & Rehab Protocols

Intra-articular Injection Within a Year of THA Predicts Early Revision

Specific Screening of MoM Hip Patients Significantly Increases Revision Surgery

Taper Analysis Supports Retention of Well-fixed Stem in Revision of MoM THA

Variables Influencing Corrosion of Modular Junctions in Metal-on-Poly THR

Lysis and Wear of Large and Standard Metal on Highly Crosslinked Poly

A Decade of Highly Crosslinked Poly in THA: A Review of 1,484 Cases

Wear of Highly Crosslinked Poly with 36mm Heads – 5 Yr Follow Up

Fixation and Wear of Contemporary Acetabulum and Crosslinked Poly at 10 Years

Prospective, Randomised Study of 2 Skin Preps in Reducing SSI after TJA

Diagnostic Threshold for Synovial Fluid Analysis in Late Peri-prosthetic Infection, Diabetes, Hyperglycemia, Hemoglobin A1c and the Risk of Joint Infections

Infection Risk Stratification in THA and TKA

Risk Factors for Infection After THA: Preventable vs Non-preventable

Do Space Suits Increase Contamination and Deep Infection in TJA

Improving Detection of PJI in THA Through Multiple Sonicate Fluid Cultures

Sonication for the Enhanced Diagnosis of Prosthetic Joint Infection

Aspiration During 2-Stage Knee Revision Inadequate for Infection Detection

Revision Rates and Outcomes Related to Duration of TKA Surgery

Does Operative Time Affect Infection Rate Following Primary TKA?

Liposomal Bupivacaine: The First 1,000 Cases in a New Era

Cement Depth and Stem Stability in Revision TKA with Hybrid Fixation

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

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

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

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

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

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

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

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

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

1.

Reconstruction of Failed Hip Abductors following THA-A New Surgical Technique using Graft Jacket Matrix

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

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

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

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

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

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

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

1.

Patient Factors

Chordoma is the second most common primary malignant tumor of the spine. These tumors rarely metastasize but are considered malignant and, when present in younger individuals, can be aggressive. In the setting of unresectable primary, recurrent, or metastatic tumors the current armamentarium of adjuvant therapy for this condition is very limited. Recent research, however, has identified potential targets for immunotherapy, including the tumor associate antigens High Molecular Weight Melanoma Associated Antigen (HMW-MAA) and B7H3.

The goal of this investigation was to correlate expression of B7H3 and HMW-MAA in chordoma tumors with disease severity and clinical outcome.

Tissue MicroArrays (TMA) were constructed using an automated arrayer to include 70 conventional chordoma tumors obtained from archives at our institution. Triplicate cores (0.6 mm in diameter) from each sample were created and two sets of cores were created for each chordoma specimen. One triplicate sample was incubated in a closed humid chamber with a pool of HMW-MAA-specific mAb, while the other was incubated with mAb specific for B7H3. Samples were washed in PBS and incubated with a secondary antibody for one hour. Staining was evaluated independently by two researchers and scored using validated systems. A retrospective chart review was performed for each chordoma specimen to determine demographic data, disease course, disease status at final follow-up and mortality. Clinical outcomes were then correlated to the expression of HMW-MAA and B7H3 within the chordoma lesions. Kaplan-Meier curves and Cox proportional hazard regression analysis were utilized to facilitate comparisons.

Chordoma tumors from 70 patients were included in this study. Average age at the time of presentation was 57.4 years (31–88 years). Average follow-up was 5.5 years (3.6 months-21 years). Forty-three patients developed recurrences and 10 had metastatic disease. Twenty-three patients (33%) had died of disease at the time of final follow-up. Ninety-seven percent of chordoma tumors stained positive for B7H3 while 44% stained positive for HMW-MAA. No correlation could be drawn between clinical course, recurrence rate, or mortality and tumor expression of B7H3 and HMW-MAA. Kaplan-Meier analysis did demonstrate a shorter survival time for patients whose tumors stained positive for HMW-MAA compared to those whose tumors were negative for the antigen.

The goal of this investigation was to correlate expression of B7H3 and HMW-MAA in chordoma tumorswith disease severity and clinical outcome. Results indicate that expression of HMW-MAA may be predictive of more aggressive disease and shorter survival. HMW-MAA and especially B7H3, in light of its near universal expression in the chordoma tumors studied here, may serve as potential targets for adjuvant immunotherapy.

There is a renewed interest in unicompartmental knee arthroplasty. The present report describes the minimum ten-year results associated with a – unicompartmental knee arthroplasty design that is in current use.

Sixty-two consecutive unicompartmental knee arthroplasties that were performed with cemented modular Miller-Galante implants in 51 patients were studied prospectively both clinically and radiographically. All patients had isolated unicompartmental disease without patellofemoral symptoms. No patient was lost to follow-up. Thirteen patients (13 knees) died after less than 10 years of follow-up, leaving 38 patients (49 knees) with a minimum of 10 years of follow-up. The average duration of follow-up was 12 years.

The mean Hospital for Special Surgery knee score improved from 55 points preoperatively to 92 points at the time of the final follow-up. Thirty-nine knees (80%) had an excellent result, six (12%) had a good result, and four (8%) had a fair result. At the time of final follow-up, 39 knees (80%) had flexion to at least 120 degrees. Two patients (two knees) with well-fixed components underwent revision to total knee arthroplasty, at seven and 11 years, because of progression of patello-femoral arthritis. At the time of the final follow-up, no component was loose radiographically and there was no evidence of peri-prosthetic osteolysis. Radiographic evidence of progressive loss of joint space was observed in the opposite compartment of nine knees (18%) and in the patello-femoral space of seven knees (14%). Kaplan-Meier analysis revealed a survival rate of 98.0% +/−2.0% at ten years and of 95.7% +/− 4.3% at 13 years, with revision or radiographic loosening as the end point. The survival rate was 100% at 13 years with aseptic loosening as the end point.

After a minimum duration of follow-up of 10 years, this cemented modular uni-compartmental knee design was associated with excellent clinical and radiographic results. Although the 10 year survival rate was excellent, radiographic signs of progression of osteoarthritis in the other compartments continued at a slow rate. With appropriate indications and technique, this uni-compartmental knee design can yield excellent results into the beginning of the second decade of use.

A post-clinical retrieval analysis was performed on 43 polyethylene tibial components of a contemporary total knee arthroplasty system with implantation duration between 12 and 80 months. Components were scored for eight potential modes of surface wear or damage on the top and back surfaces. Moderate backside wear of 4.1μm per year was documented by measuring the extent of manufacturer’s engraved lettering removal. Neither the topside nor backside score correlated with duration of in vivo function. No component experienced topside or backside delamination, cracking, or significant deformation. The greatest contribution to wear and damage score was pitting and scratching secondary to bone cement debris. The extent of both wear and damage experienced by these components was moderate, in comparison with that previously reported with older implant systems.

Previously, we conducted a single surgeon in vivo kinematic study that revealed subjects having a PCR TKA with asymmetrical condyles experienced a high incidence of posterior femoral rollback. Therefore, the objective of this follow-up study was to determine if posterior femoral rollback from our single surgeon series can be attributed to the implant design, surgical technique, or the presence of a well functioning PCL.

Three-dimensional femorotibial contact positions for eighty subjects, implanted by three surgeons, were evaluated using fluoroscopy during a deep knee bend. Twenty subjects had a PCR TKA without a PCL, while the other 60 subjects were deemed to have a functional PCL. All subjects were implanted with a PCR TKA having a larger lateral radius of curvature compared to the medial condyle.

Fifty-four of sixty subjects in this study having a functional PCL experienced posterior femoral rollback of the lateral condyle, while 13/20 subjects not having a PCL experienced posterior femoral rollback. Also, 48/60 subjects having a well functional PCL and 10/20 subjects without a PCL experienced a normal axial rotation pattern. The incidence for condylar lift-off was low, and only 6/80 subjects in this study experienced greater than 2.0 mm of condylar lift-off. Forty of sixty subjects having a well-functional PCL experienced greater than 100 degrees of weight-bearing range-of-motion and the maximum weight-bearing range-of-motion was 144o.

The subjects in this study experienced excellent kinematic patterns, consistent to the normal knee, although less in magnitude than the normal knee. Surprisingly, on average, subjects in this study without a PCL experienced posterior femoral rollback of the lateral condyle leading to the assumption that the PCL did not play a significant role in the excellent kinematic patterns achieved by subjects in this study. The results from this study do support the hypothesis derived from our single surgeon series that asymmetric condylar geometry may lead to better kinematic patters for subjects implanted with a fixed bearing PCRTKA, as it appears implant design is the most influencing factor that lead to normal kinematic patterns.

Introduction and Aims: Due to relative motion that can occur between the polyethylene articular surface and tibial tray, backside wear of modular tibial components can be a significant contributor to wear in TKR. This study examines the backside wear performance of a tibial component system from both a laboratory and clinical perspective.

Method: Polyethylene components, CR and PS, from the NexGen knee system (Zimmer Inc.) were evaluated for backside wear. These components were identified on the back surface by the manufacturer with engraved lettering of a depth ranging from 20 to 30 micrometers. Twenty-seven components retrieved after 24 to 80 months in-situ were evaluated along with six components having undergone three million cycles of laboratory knee function simulation. Backside wear was quantified by engraving mark depth and screw hole recess penetration measurements utilising a New View 5000 scanning white light interferometer (Zygo). The severity of third-body abrasion was also recorded.

Results: This particular knee system utilised a peripheral rail and dovetail polyethylene locking mechanism which demonstrated little relative polyethylene to tibial tray motion during joint function simulation. Simulator testing produced backside wear of 6.4 micrometers/million cycles or 4.5 mm3/million cycles. This backside wear represented 30% of total component wear as measured gravimetrically. Backside wear in the clinically retrieved components was sufficient to completely remove the manufacturer’s engraving marks on only three of 27 components. The remaining 24 components all experienced backside wear insufficient to remove all engraving. The severity of third-body abrasion (typically bone cement) was generally associated with greater backside wear. Two of the three clinically retrieved components with worn-through lettering had evidence of significant third-body wear. In 11 clinically retrieved components (utilised on tibial trays with screw holes), backside wear was measured by comparing engraving mark depth in unworn polyethylene areas over screw recesses with engraving mark depth in areas of polyethylene contact with the tibial tray. These components demonstrated 14 micrometers of wear at an average of 37 months in-situ or 4.4 micrometers per year. None of the retrieved components were clinically associated with osteolysis.

Conclusion: In this particular tibial component system, backside wear was moderate for both the joint simulator and clinically retrieved specimens. Backside wear does not appear to be the major contributor of total polyethylene wear in this implant system. The presence of third-body particles contributed to greater wear.

The Acetabulum – In primary total hip arthroplasty the choices between cemented and cementless acetabular reconstruction are relatively simple. For the vast majority of surgeons now in practice cementing acetabular components is a relatively little practiced skill. Difficulty in minimising blood at the interface, pressurisation of the cement and the inability to easily use modularity makes this a less attractive option for most surgeons. That is not to say that good results cannot be routinely achieved and that there is anything wrong with this approach. Cementless fixation of the acetabulum is also reliable. Current controversies remain in the realm of adjuvant fixation techniques (degree of press fit, screw usage and other adjuvant fixation techniques.) Poly wear and concern with backside wear and rigidity of modular polyethylene capture remain concerns. In the realm of revision, cementless fixation has become the standard method for most revision surgeons and is employed in over 90% of cases. Here, the use of screws is less controversial. Cement is used almost exclusively to fix components to anti-protrusion cages.

The Femur – Fixation of the femoral component remains more controversial. Cemented stems currently available employ a wide variety of design features and surface finishes, and controversy regarding appropriate design and surface finish is extensive. However, the development of a symmetric cement mantle about the entire stem is considered an essential feature of modern cement technique. Cementless fixation has been shown to be effective in multiple settings including the aged and in patients with avascular necrosis and with inflammatory arthritis. Designs including proximally coated, extensively coated, and hydroxyapatite coated in straight, tapered and anatomic stem designs have all demonstrated good intermediate term results. The most concerning issue is the migration of particulates about the effective joint space and most implants attempt to create an ingrowth seal about the proximal part of the stem to prevent egress of particulates more distally. While concern remains about long-term stress shielding of proximal bone, there is little in the way of clinical data to support these concerns. Some data indicate that tapered stems, proximally coated stems with distal fixation features and extensively coated stems are more reliable at preventing thigh pain but, this issue appears significantly less problematic now than it did a decade ago.

Revision components are largely cementless and extensively coated though there is good evidence that roughened surface tapered components can be effective in the revision setting and that stem modularity, while adding potential long-term problems, may allow for greater intraoperative adaptability.

Avoidance of extensor mechanism complications is best obtained by using components with an appropriately designed femoral trochlea and patellar component and where internally rotated components are avoided. Residual valgus deformity may also lead to patellar dislocation or more subtle subluxations, which may manifest as pain along the medial patellar retinaculum. Because rotational abnormalities are difficult to detect on plain x-ray, CT scans are a useful way to diagnose this problem. Peripatellar crepitation may cause symptoms and can be avoided by aggressive peripatellar synovectomy at the time of surgery. In its most severe form, the patellar clunk syndrome, most commonly seen in posterior stabilised knees, arthroscopic debridement of the offending fibrous nodule may be needed. Patellar fracture is best treated on the basis of residual extensor mechanism function. Maintenance of active extension following fracture (with no loss of component fixation) is a good sign that conservative therapy will yield better function than ORIF. Loss of extension indicates that surgery will be required. In this setting restoration of extensor continuity is more important than retention of the patellar component. Patellar tendon avulsion can be avoided by careful attention to the tendon during surgical exposure. Intraoperative repair alone is rarely successful and should be reinforced by semitendonosis, or fascia lata grafting. Late rupture may be treated by this type of grafting alone. But if the patella is necrotic or the failure results in a high riding patella, mechanism transplant is preferred. In this setting attention to fixing the graft in full extension is mandatory to prevent severe extensor lag, as the allograft will stretch out overtime.

Several centres have reported short-term (minimum 18–24 months) follow-up using cancellous impaction grafting with cement for femoral component revision, most often using stems of a similar geometry. The technique was described using the Exeter stem (Howmedica, Rutherford, NJ and Howmedica International, Staines, Middlesex, England), which is a double-tapered, highly polished, non-collared device; another implant commonly used for the procedure, the CPT stem (Collarless Polished Taper; Zimmer, Warsaw, IN), is similar in appearance. Advocates of the technique using these devices state that subsidence does not automatically lead to clinical loosening because the stem’s so-called “self-tightening geometry” allows re-stabilisation within the cement mantle as subsidence occurs. Cold flow of the cement mantle may help the stem to subside without becoming symptomatically loose. Subsidence of the wedge-shaped stem may also provide a beneficial compressive load to the bone graft.

However, other authors have raised concerns about the supposed benign nature of stem subsidence, and impaction allografting has been performed using stems that resist subsidence. Implants with a rough surface finish and polymethylmethacrylate precoating have been used.

When evaluating the published reports on impaction allografting, two important issues limit comparisons between clinical series. The most evident limitation is the inconsistent use of inclusion criteria in those papers. While many series have attempted to limit inclusion to femurs with more advanced stages of bone stock deficiency, others have specifically excluded some of those patients, as one of the originators of the procedure has expressed concerns about expanding the indications for impaction grafting to the most challenging femoral revisions. Some have been groups of consecutive patients undergoing femoral revisions, while still other studies do not define any criteria for inclusion at all. Another important limitation to consider when comparing clinical reports on this technique is the impressive number of variables that may impact on outcome in a femoral revision using impaction allografting. Two series using similar implants and similar inclusion criteria may still differ with respect to cement (technique, type, viscosity), allograft (source, consistency, pretreatment with radiation or freeze-drying), surgical approach, and aftercare, to name but a few potentially important factors. The effects of most of these variables on results in this especially complex technique have yet to be described.

An analysis of the cement mantle obtained with the Exeter impaction allografting system at one centre showed that it was either deficient or absent in almost 47% of Gruen zones. We therefore examined the mantle obtained using this system at another hospital and compared the results with those from the CPT and Harris Precoat Systems at other centres.

The surgical indications for the procedure and the patient details were broadly similar in all four hospitals. There was some variation in the frequency of use of cortical strut allografts, cerclage wires and wire mesh to supplement the impaction allograft. Analysis of the cement mantles showed that when uncertain Gruen zones were excluded, the incidence of zones with areas of absence or deficiency of the cement was 47% and 50%, respectively, for the two centres using the Exeter system, 21% for the CPT system and 18% for the Harris Precoat system.

We measured the difference in size between the proximal allograft impactors and the definitive prosthesis for each system. The Exeter system impactors are shorter than the definitive prosthesis and taper sharply so that the cavity created is inadequate, especially distally. The CPT proximal impactors are considerably longer than the definitive prosthesis and are designed to give a mantle of approximately 2 mm medially and laterally and 1.5 mm anteriorly and posteriorly. The Harris Precoat proximal impactors allow for a mantle with a circumference of 0.75 mm in the smaller sizes and 1 mm in the larger.

Many reports link the longevity of a cemented implant to the adequacy of the cement mantle. For this reason, femoral impaction systems require careful design to achieve a cement mantle which is uninterrupted in its length and adequate in its thickness. Our results suggest that some current systems require modification.

We have reviewed 25 cases of focal femoral osteolysis in radiographically stable, cemented femoral implants. In three hips retrieved at post-mortem from two patients, we have been able to make a detailed biomechanical and histological analysis. The interval between arthroplasty and the appearance of focal osteolysis on clinical radiographs ranged from 40 to 168 months, and in over 70% of the cases this did not appear until after five or more years. Few had significant pain and there was no relation to age, sex or original diagnosis. The most common site for osteolysis were Gruen zones 2 and 3 on the anteroposterior radiograph and zones 5 and 6 on the lateral radiograph. In 15 cases (60%), the area of osteolysis corresponded to either a defect in the cement mantle or an area of very thin cement. The rate of progression of these lesions was variable, but to date only one has progressed to gross loosening of the femoral component. The back-scatter scanning electron microscopic examination of serial sections and biomechanical testing of the post-mortem specimens demonstrated focal cement fracture around implants that were otherwise rigidly fixed. In eight cases from which tissue was available, histology showed a histiocytic reaction with evidence of particulate polymethylmethacrylate. We consider that this local fragmentation was the stimulus for local osteolysis in an otherwise stable cemented femoral component.