Gracia Etienne

the Outcome of Total Knee Arthroplasty in Obese Patients

BACKGROUND Evidence linking increased body weight to osteoarthritis of the knee and the high prevalence of obesity underscore the importance of defining the outcome of total knee arthroplasty in obese patients. The purpose of this study was to compare the clinical and radiographic results of total knee arthroplasties performed in obese patients with those of total knee arthroplasties performed in nonobese patients. METHODS Clinical and radiographic data on seventy-eight total knee arthroplasties in sixty-eight obese patients were compared with data on a matched group of nonobese patients. The analysis was also performed after stratification of the obese group for the degree of obesity. All patients had the same prosthesis. The clinical data that were analyzed included the Knee Society objective and functional scores, patellofemoral symptoms, activity level, and complications. RESULTS The percentage of knees with a Knee Society score of > or =80 points at an average of eighty months was 88% in the obese group, which was significantly lower than the 99% rate in the nonobese group at the same time. The morbidly obese subgroup had a significantly higher revision rate than did the nonobese group (p = 0.02). CONCLUSIONS The results of the present study suggest that any degree of obesity, defined as a body mass index of > or =30, has a negative effect on the outcome of total knee replacement.

Hip resurfacing arthroplasty.

Abstract Hip resurfacing arthroplasty is a type of hip replacement that involves capping the femoral head and preserving bone of the proximal femur. Metal‐on‐metal surface replacements have been manufactured since the early 1990s. Recent studies indicate excellent clinical results with low failure rates at 1‐ to 5‐year follow‐up. Although these early results are encouraging, resurfacing devices must be used with caution because less is known about their long‐term safety and efficacy. The best candidates for resurfacing are patients younger than age 60 years with good bone stock. The surgical approach is similar to that for standard total hip replacements, but with slightly more dissection because the femoral head must be preserved and displaced to visualize the acetabulum. To reduce complications, resurfacing arthroplasty should be performed by surgeons who have received training specifically in this technique.

Core decompression of the femoral head for osteonecrosis using percutaneous multiple small-diameter drilling.

Osteonecrosis is a disease with a wide ranging etiology and poorly understood pathogenesis seen commonly in young patients. Core decompression has historically been used in patients with small-sized or medium-sized precollapse lesions in an attempt to forestall disease progression. Typically, an 8-10 mm wide cannula trephine is used to do this procedure. The authors report on a new technique using multiple small drillings with a 3-mm Steinman pin to effectuate the core decompression. In this report, there were 32 of 45 hips (71%; 35 patients) with a successful clinical result at a mean followup of 2 years (range, 20-39 months). Twenty four of 30 Stage I hips (80%; 23 patients) had successful outcomes compared with 8 of 15 Stage II hips (57%; 12 patients) with no surgical complications occurring with this technique. This procedure is technically straightforward and led to minimal morbidity with no surgical complications. It may be effective in delaying the need for total hip arthroplasty in young patients with early (precollapse) stages of femoral head osteonecrosis.

Use of bone morphogenetic proteins for musculoskeletal applications. An overview.

Since Marshall Urists original description, in 1965, of the potential of demineralized bone matrix to induce bone formation, the medical community has anticipated the development of osteogenic therapies1. Following this discovery, researchers sought to identify and isolate these growth factors, specifically bone morphogenetic proteins (BMPs). Reddi and Huggins first characterized these important molecules involved in bone formation in 1973, and, in 1982, Sampath and Reddi developed a rat subcutaneous assay for BMP activity that measures bone formation2. They found that BMPs initiate the bone-healing cascade through the recruitment of and interactions with mesenchymal stem cells found in surrounding tissues, including fascial planes, periosteum, peripheral blood, bone marrow, and cancellous bone. Several, but not all, of the fifteen human BMPs described to date have been found to bind to stem-cell receptors, triggering proliferation and differentiation, and to result in bone regeneration and repair. Once various BMPs were successfully isolated, a variety of animal models were used to test their efficacy in musculoskeletal applications. Early studies included bone-defect models as well as models of cartilage development, spinal fusion, and maxillofacial restoration. The healing of critical-sized defects in long bones was assessed in a variety of animal species, including rabbits, sheep, dogs, and primates3 (Figs. 1-A and 1-B). Fig. 1-A Canine model showing a surgically created 2-cm defect. Fig. 1-B New bone formation was noted across all BMP-treated defects. New insights into the nature of bone biology and the ability to manufacture proteins through recombinant gene technology have led to the commercialization of two BMPs: BMP-7 (OP-1; Stryker, Kalamazoo, Michigan) and BMP-2 (Infuse; Medtronic Sofamor Danek, Memphis, Tennessee). In addition, other BMPs or BMP-combination products are being evaluated clinically; these include various isolates of animal and human BMP implants, BMPx (Sulzer Biologics, Wheat Ridge, Colorado), BMP-9, and others. While current use …

Outcome of nonvascularized bone grafting for osteonecrosis of the femoral head

Osteonecrosis is a disease with a wide-ranging etiology and poorly understood pathogenesis seen commonly in young patients. Various head-preserving procedures have been used for this disease to avert the need for total hip replacement. These include various vascularized and nonvascularized bone grafting procedures. We will describe the use of bone-grafting through a window at the femoral head-neck junction for the treatment of osteonecrosis of the femoral head. Bone morphogenetic protein (BMP)-enriched allograft was used to avoid donor site morbidity. Nineteen patients (21 hips) were followed up for a mean of 48 months (range, 36–55 months) after a bone grafting procedure in which the diseased bone was replaced by a bone graft substitute (combination of demineralized bone matrix, processed allograft bone chips, and a thermoplastic carrier). Eighteen of 21 hips (86%) were clinically successful at latest followup. Two of these patients have minimal radiographic progression (< 2 mm head collapse). This procedure is straightforward technically, led to low morbidity, and did not necessitate procurement of donor site bone graft. This procedure may be effective at avoiding or forestalling the need for total hip arthroplasty in young patients with early to intermediate stages of osteonecrosis of the femoral head.

Functional problems and treatment solutions after total hip and knee joint arthroplasty

A lthough most patients who undergo total hip or knee joint arthroplasty have an excellent clinical result with routine postoperative interventions, substantial dysfunction develops in 15% to 20% of patients for various reasons1. These patients do not respond to standard physical therapy modalities and need a very aggressive regimen of management that may include both invasive and noninvasive therapeutic options. The purpose of this study was to identify these patients with functional limitations and to assess the results of treatment with a customized regimen. We defined soft-tissue problems as those not directly related to the implant. Implant-related problems due to malalignment or loosening were ruled out radiographically or by specialized testing by two of the authors (M.M. and G.E.). We identified several functional problems following total hip arthroplasty and total knee arthroplasty that were related to muscle weakness, muscle tightness, limb-length differences, and nerve problems (Table I). View this table: TABLE I Problems Following Total Hip and Knee Arthroplasty After identification of the problems, management was initiated with either noninvasive treatment such as physical therapy, customized bracing, electrical stimulation, or iontophoresis or with invasive treatment such as injections of Botox (botulinum toxin type A; Allergan, Irvine, California), intraarticular injections, nerve blocks, or muscle-lengthening procedures. For patients exhibiting joint stiffness, a lack of extension, or a lack of flexion (<90°) following total knee arthroplasty, we developed a special customized protocol utilizing a customized hinged cast and adjunctive physical therapy. We identified problems with the soft-tissue envelope that were directly related to the joint in the majority of patients. In addition, some patients had problems affecting an adjacent joint that resulted in poor gait and function, such as malalignment of the knee joint in a patient who had had a total hip arthroplasty or malalignment of the foot in a patient who had had …

The incorporation of morselized bone grafts in cementless acetabular revisions.

The treatment of large osteolytic lesions is a challenge during acetabular revisions. Periprosthetic bone loss can compromise the stability of new implants. The purpose of this study was to evaluate the 5- to 10-year clinical and radiographic results of morselized bone grafting for acetabular osteolysis during cementless acetabular revisions. Ninety-nine patients (108 hips) who had an acetabular revision hip arthroplasty for osteolysis were retrospectively reviewed. There were 44 men and 55 women who had a mean age of 66 years. At the index revision, the acetabular defects were debrided of granulomatous tissue and packed tightly with morselized cancellous femoral head allograft. All the revision acetabular components were implanted using cementless fixation. At a mean followup of 85 months (range, 60–118 months), the results of 103 of 108 hips (95%) were clinically and radiographically successful. The mean preoperative Harris hip score was 37 points, which improved to a mean of 91 points at the last followup. All cavitary defects had complete radiographic incorporation of the bone grafts except for two lesions. The results of this study indicate that morselized bone graft incorporates into cementless acetabular revisions. This treatment method provided a stable reconstruction in 98% of patients at a mean of 7 years followup.

Use of a Functional Temporary Prosthesis in a Two-Stage Approach to Infection at the Site of a Total Hip Arthroplasty

Two-stage revision arthroplasty is the gold standard for treatment of infection at the site of a total hip arthroplasty1-9. Unfortunately, removal of the components followed by a delay for antibiotic treatment can result in prolonged morbidity5,6. We describe two novel approaches to two-stage revision arthroplasty. ### General Description (Figs. 1-A, 2, 3) In thirty-two consecutive patients with an infection at the site of a total hip arthroplasty, we utilized a spacer composed of either the removed femoral component, which was autoclaved and then reimplanted, or an inexpensive modular femoral component. The femoral implant is coated with a mantle of antibiotic-impregnated polymethylmethacrylate before reinsertion3,7. A polyethylene acetabular liner is cemented in place with the same antibiotic-impregnated polymethylmethacrylate. The construct functions like a conventional total hip prosthesis but is intended to be utilized as a temporary implant in patients undergoing a two-stage approach to the management of an infection at the site of a total hip arthroplasty. Figs. 1-A, 1-B, and 1-C This sixty-nine-year-old patient presented with disabling pain seven years after a primary total hip arthroplasty. Fig. 1-A The preoperative anteroposterior radiograph shows loose …

Use of Constrained Acetabular Liners in Total Hip Arthroplasty

The use of constrained acetabular liners is indicated when soft-tissue tensioning techniques such as femoral neck lengthening, component repositioning, and use of lateralized acetabular liner are ineffective. It is most commonly used as a salvage procedure in revision situations. However, a locking acetabular insert may be used for primary THAs in patients with joint or soft-tissue laxity, neuromuscular disease, or intraoperative instability. In addition to the described commercially available liners, several manufacturers will provide customized components on request.

Treatment of Osteonecrosis of the Knee

The knee joint is the second most common site for osteonecrosis with approximately a 10% incidence of the disease in the femoral head. Two separate entities exist: (1) spontaneous osteonecrosis of the knee (SPONK) and (2) secondary osteonecrosis of the knee. They are differentiated by age of presentation, associated risk factors, location, laterality, and condylar involvement. Each of these entities has several distinct surgical treatment options. These include arthroscopic debridement, core decompression, osteochondral allografting and autografting, osteotomy, unicompartmental knee arthroplasty, and total knee arthroplasty. It is essential to diagnose these 2 entities as early as possible to use appropriate treatment to avoid osteoarthritis, joint destruction, and ultimately joint collapse. In a following article, we discuss the evaluation, indications/contraindications, techniques, results, and possible future treatments of these two entities: SPONK and secondary osteonecrosis.