Instability in total knee arthroplasty : assessment and solutions.

Instability is a common indication for early revision after both primary and revision total knee arthroplasty (TKA), accounting for up to 20% in the literature. The number of TKAs performed annually continues to climb exponentially, thus having an effective algorithm for treatment is essential. This relies on a thorough pre- and intra-operative assessment of the patient. The underlying cause of the instability must be identified initially and subsequently, the surgeon must be able to balance the flexion and extension gaps and be comfortable using a variety of constrained implants. This review describes the assessment of the unstable TKA, and the authors' preferred form of treatment for these difficult cases where the source of instability is often multifactorial.

The multiply-operated total knee replacement patient: salvage options.

Although the vast majority of patients that undergo total knee replacement have satisfactory outcomes with a generally low complication rate, occasionally a patient will be encountered that has had multiple failed surgeries, and now reaches a crossroad as to whether limb salvage will be acceptable or not.

When femoral fracture fixation fails: salvage options.

Most hip fractures treated with modern internal fixation techniques will heal. However, failures occasionally occur and require revision procedures. Salvage strategies employed during revision are based on whether the fixation failure occurs in the femoral neck, or in the intertrochanteric region. Patient age and remaining bone stock also influence decision making. For fractures in young patients, efforts are generally focused on preserving the native femoral head via osteotomies and repeat internal fixation. For failures in older patients, some kind of hip replacement is usually selected. Disuse osteopenia, deformity, bone loss, and stress-risers from previous internal fixation devices all pose technical challenges to successful reconstruction. Attention to detail is important in order to minimise complications. In the majority of cases, good outcomes have been reported for the various salvage strategies.

Pelvic discontinuity: current solutions.

Pelvic discontinuity represents a rare but challenging problem for orthopaedic surgeons. It is most commonly encountered during revision total hip replacement, but can also result from an iatrogentic acetabular fracture during hip replacement. The general principles in management of pelvic discontinuity include restoration of the continuity between the ilium and the ischium, typically with some form of plating. Bone grafting is frequently required to restore pelvic bone stock. The acetabular component is then impacted, typically using an uncemented, trabecular metal component. Fixation with multiple supplemental screws is performed. For larger defects, a so-called 'cup-cage' reconstruction, or a custom triflange implant may be required. Pre-operative CT scanning can greatly assist in planning and evaluating the remaining bone stock available for bony ingrowth. Generally, good results have been reported for constructs that restore stability to the pelvis and allow some form of biologic ingrowth.

Subcapital fractures: a changing paradigm.

Options for the treatment of subcapital femoral neck fractures basically fall into two categories: internal fixation or arthroplasty (either hemiarthroplasty or total hip arthroplasty). Historically, the treatment option has been driven by a diagnosis-related approach (non-displaced neck fractures versus displaced neck fractures). More recently, the traditional paradigm has changed. Instead of a diagnosis-related approach, it has become more of a patient-related approach. Treatment options take in to consideration the patient's age, functional demands, and individual risk profile. A simple algorithm can be helpful in terms of directing the treatment. Non-displaced fractures, regardless of age of the patient, should be treated with closed reduction and internal fixation. For displaced femoral neck fractures, the treatment differs depending on the age of the patient. The younger patient should be treated with urgent ORIF with the goal of an anatomic reduction. For displaced femoral neck fractures in the elderly, cognitive function should be determined. For those who are cognitively functioning, total hip arthroplasty appears to be the best option. In the cognitively dysfunctional, a bipolar hemiarthroplasty or a total hip arthroplasty with use of larger heads (32 mm or 36 mm) and/or constrained sockets are a viable option.

Metastatic disease around the hip: maintaining quality of life.

Many tumors metastasise to bone, therefore, pathologic fracture and impending pathologic fractures are common reasons for orthopedic consultation. Having effective treatment strategies is important to avoid complications, and relieve pain and preserve function. Thorough pre-operative evaluation is recommended for medical optimization and to ensure that the lesion is in fact a metastasis and not a primary bone malignancy. For impending fractures, various scoring systems have been proposed to determine the risk of fracture, and therefore the need for prophylactic stabilisation. Lower score lesions can often be treated with radiation, while more problematic lesions may require internal fixation. Intramedullary fixation is generally preferred due to favorable biomechanics. Arthroplasty may be required for lesions with massive bony destruction where internal fixation attempts are likely to fail. Radiation may also be useful postoperatively to minimise construct failure due to tumor progression.

Osteolysis in the well-fixed socket: cup retention or revision?

Osteolysis remains a common reason for revision after total hip arthroplasty (THA). For osteolysis associated with loose cups, revision is indicated. For osteolysis around a well-fixed cup, the decision is more controversial. The data available data support retention of the cupwith lesional treatment, working through screw holes and access channels for debridement and grafting. The choice of graft material to fill defects, if any, remains controversial. Several studies demonstrate good survivorship with cup retention strategies. Complete revision allows more complete debridement of the lesion and better graft fill, and allows implantation of a modern cup, typically with a full line of liners and bearing surfaces available. Additionally, revision allows fine tuning of the orientation of the cup, which may be advantageous for optimising hip stability. The author prefers to retain a well-fixed cup if it meets the following criteria: it is well-fixed to intra-operative testing, it is well-positioned, it is of sufficient size to allow insertion of a new liner with a reasonable head size, new liners are available, and the hip is stable to intra-operative trialing after liner insertion.

Fatal sepsis in a patient with rheumatoid arthritis treated with etanercept.

Patients with long-standing, severe, erosive rheumatoid arthritis who have extra-articular manifestations and have undergone joint replacement surgery are at increased risk for serious infection and premature mortality. New therapies, including cytokine antagonists, hold great promise for improving the course of rheumatoid arthritis. However, they have powerful anti-inflammatory effects that may mask symptoms of serious infection. We report a case of fatal pneumococcal sepsis occurring in a 37-year-old woman with rheumatoid arthritis treated with the tumor necrosis factor antagonist etanercept and suggest management strategies for early detection and management of this complication.

Reverse obliquity fractures of the intertrochanteric region of the femur.

BACKGROUND: The reverse obliquity fracture of the proximal part of the femur is a distinct fracture pattern that is mechanically different from most intertrochanteric fractures. The purpose of this retrospective study was to determine the prevalence of these fractures and the results and complications of different types of internal fixation used in their treatment. METHODS: Between 1988 and 1998, 2472 consecutive patients with a hip fracture were treated at our Level-One Trauma Center; 1035 of the fractures were classified as intertrochanteric or subtrochanteric. Clinical and radiographic records were retrospectively reviewed, and fifty-five fractures with a reverse obliquity pattern were identified. Forty-nine patients were followed until the fracture united or a revision operation was performed. The duration of clinical follow-up averaged eighteen months (range, three to sixty-seven months), and the duration of radiographic follow-up averaged fifteen months (range, three to sixty months). Fractures were classified with the Orthopaedic Trauma Association scheme. Results were analyzed according to the fracture pattern, type of implant, quality of the reduction, position of the implant, and use of bone graft at the index operation. Function was assessed on the basis of pain, living situation, need for walking aids, need for analgesics, and walking capacity. RESULTS: Thirty-two (68%) of forty-seven hips treated with internal fixation healed without an additional operation. Fifteen (32%) of the forty-seven failed to heal or had a failure of fixation. The failure rate was nine of sixteen for the sliding hip screws, two of fifteen for the blade-plates, three of ten for the dynamic condylar screws, one of three for the cephalomedullary nails, and zero of three for the intramedullary hip screws. Use of the fixed-angle devices (the blade-plate and the dynamic condylar screw) resulted in fewer failures than did use of the sliding hip screw (p = 0.023). Eleven (46%) of twenty-four nonanatomically reduced fractures and four (17%) of twenty-three anatomically reduced fractures had a failure of treatment (p = 0.060). Eleven (26%) of forty-two fractures with an ideally placed implant and four (80%) of five fractures with a non-ideally placed implant had a failure of treatment (p = 0.023). Of the fifteen fractures that failed to heal or had a failure of fixation, five were treated with revision to a calcar-replacement prosthesis, seven were treated with revision open reduction and internal fixation with bone-grafting, and one was treated with bone-grafting without revision of the fixation. Two patients refused additional surgery because they had limited functional demands. The two-year mortality rate was 33%. Functional results were poor, with many patients requiring walking aids and losing the capacity for independent walking and self-care. CONCLUSIONS: In this series, reverse obliquity fractures accounted for 2% of all hip fractures and 5% of all intertrochanteric and subtrochanteric fractures. Ninety-five-degree fixed-angle internal fixation devices performed significantly better than did sliding hip screws. Results were also worse for fractures with poor reduction and those with a poorly placed implant.