A biomechanical evaluation of one-stage vs two-stage bilateral knee arthroplasty patients.

In this study the functional abilities of eight one-stage bilateral total knee replacement (TKR) patients were compared to five two-stage bilateral TKR and nine control subjects. The TKR individuals were an average of 62 months post-operative. Based on gait analysis, ground reaction force profiles during walking and isometric knee strength assessment, the one-stage individuals did not differ significantly from the control subjects. The two-stage individuals had significantly less knee range of motion during gait and smaller vertical ground reaction forces during the braking phase than the control and one-stage individuals. To compare left and right sides, a symmetry index was computed and there were no significant differences among the three groups. Based on the variables tested in this biomechanical evaluation it can be concluded that for individuals facing bilateral knee replacement a one-stage procedure can result in functional capabilities at least comparable to a two-stage procedure.

Characterization of debris adjacent to failed knee implants of 3 different designs.

Wear debris particles have been associated with bone resorption and loosening of total joint implants. To characterize the wear particles around failed knee prostheses, tissues adjacent to 47 implants of 3 different designs were evaluated: 29 were posterior cruciate ligament retention type (Group I), 12 were posterior cruciate ligament sacrificing or substituting (Total Condylar, Insall-Burstein), (Group II), and 6 were mobile bearing (posterior cruciate ligament retaining LCS), (Group III). Wear particles were isolated and evaluated using electronic particle quantitation and scanning electron microscopy. The corresponding implants were also evaluated, and the surface damage quantified. The number of particles smaller than 10 microm ranged from 8.9 to 45.8 x 10(9) per gram of tissue (dry weight). Particle number directly correlated with duration of implantation. Group I implants had larger particles, and showed greater surface damage than the other 2 designs. Polyethylene surface damage significantly correlated with particle size more than 10 microm in length. Particle number showed a significant inverse correlation with the thickness of the polyethylene. These results support previous mechanical and retrieval studies suggesting that increased wear may be associated with thinner polyethylene, and there are differing degrees and patterns of wear based on implant design.

Classification of femoral abnormalities in total hip arthroplasty.

Bony abnormalities of the femur can significantly complicate total hip arthroplasty both for the primary and revision operations. No standard nomenclature exists for the description of these femoral abnormalities. A classification system is presented to standardize nomenclature, assist in preoperative planning, and to assist in the reporting of these defects.

The rationale for cementless revision total hip replacement with contemporary technology.

Undoubtedly, the number of revisions for failed cemented total hip arthroplasties will increase over time based on current survival statistics. Although contemporary cementing techniques may improve the outcome of some procedures, long-term results of cemented revisions are less than ideal. Poor bone quality with cortical deficiencies and endosteal sclerosis make long-term stability and implant survival less likely with cemented techniques. In the very elderly patient requiring revision, PMMA may provide a simpler option with an adequate short-term result. Using uncemented techniques, the complications associated with the inherent properties of cement can be avoided. Bone grafting is a viable option, with the hope that long-term implant stability can be achieved by biological ingrowth into porous surfaces. Reconstitution of previously attenuated cortical bone is seen after bone grafting in association with a noncemented femoral or acetabular implant, although ingrowth into porous-coated surfaces via allograft bone is unlikely. In general, short- and mid-term results with respect to clinical performance are good or excellent in at least 90% of the cases evaluated. With the increased application of uncemented components to revision situations, attention may shift from "cement" disease to "polyethylene" disease. Although not the focus of this article, recent literature with respect to primary uncemented hip and knee arthroplasty supports this contention. We believe that proximal canal fill and biologic ingrowth can provide implant stability, avoid proximal stress shielding of the femur, and improve long-term implant survival and clinical success in the revision situation.

Allograft reconstruction of the acetabulum in revision hip surgery.

Acetabular deficiencies seen in revision hip arthroplasty require special attention. Custom components, space-filling cement, relocation of the hip center higher on ilium, and resection arthroplasties have all been used. Allograft reconstruction of acetabular defects has many attractive features, but methods of fixation, long-term success rates, and problems of graft resorption and implant loosening present significant questions. This article presents a classification system for acetabular defects and a surgical technique for correcting them. The results of 218 cementless acetabular reconstructions are reviewed and show the importance of the acetabular rim. When the rim is intact, 97% of reconstructions will remain stable, and 78% of allografts used will consolidate. When the acetabular rim is deficient, special techniques using bulk allograft and internal fixation must be used in order to avoid long-term graft resorption and implant loosening.

Polyethylene debris-induced osteolysis and loosening in uncemented total hip arthroplasty. A cause of late failure.

Uncemented total hip arthroplasty has proven to be an acceptable alternative to cemented total hip arthroplasty with good short-term results. With the elimination of the use of polymethyl methacrylate for component fixation, failure at the bone-cement interface, with resultant osteolysis and progressive loosening, was thought to be preventable. Unfortunately the ultra-high-molecular-weight polyethylene acetabular insert can wear and produce particulate debris. This debris can stimulate an osteolytic reaction and lead to late aseptic loosening in a cementless total hip arthroplasty.

Classification and management of acetabular abnormalities in total hip arthroplasty.

Total hip arthroplasty, for both primary and revision operations, frequently involves bony abnormalities of the acetabulum. No standard nomenclature currently exists for the definition of acetabular deficiencies. A classification system is presented to assist in the preoperative evaluation and to provide a treatment protocol for these defects.

Hematogenously acquired infection of a total knee arthroplasty by Clostridium perfringens.

A 64-year-old man with total knee arthroplasty for tricompartmental osteoarthritis had a postoperative course complicated by an attack of acute cholecystitis and was treated with cholecystectomy. The TKA was hematogenously seeded with Clostridium perfringens, which necessitated emergency removal of the implants, debridement, and ultimately arthrodesis.

Capitellocondylar total elbow arthroplasty. Two-to eight-year experience.

A series of 35 capitellocondylar total elbow arthroplasties was performed on 29 patients. The average patient age at the time of surgery was 58 years (range, 28-71 years). Follow-up study averaged 5.6 years (range, 2-8 years). The complication rate was 57%. There were three infections, three dislocations, and two intraoperative fractures. Transient ulnar nerve palsy occurred in nine patients, postoperative hematomas in two patients, and intraoperative perforation of the ulna cortex in one patient. Aseptic loosening occurred around the humeral component of one elbow. No ulnar components developed aseptic loosening. Range of motion increased in all planes, except extension. Pain relief was achieved in all but one patient. There were no unstable elbows.

Infected total knee arthroplasty. A protocol for management.

All cases of deep wound infection following total knee arthroplasty presented to the senior author between April 1977 and February 1984 were reviewed in an attempt to develop a protocol for salvaging a functional, painless knee. Two of 23 knees were eliminated because of extensive soft tissue loss. The remaining 21 infected total knee arthroplasties were analyzed. A determination of the chronicity of the infection and an evaluation of any radiolucencies were essential in determining the type of treatment used. Three distinct methods of surgical management were identified: radical debridement with retention of the initial prosthesis, one-stage reimplantation, and two-stage reimplantation. A functional uninfected total knee arthroplasty was salvaged in 18 of 21 patients, with an average follow-up period of 46 months.

Two-year follow-up of the PCA noncemented total hip replacement.

The early results with the PCA total hip replacement have been most gratifying, especially the absence of complications related to the acetabular component. The radiographic evaluation was done critically, and the finding of no progressive acetabular radiolucencies was unexpected. Longer-term evaluation of these interfaces is necessary, but the short-term results have been encouraging. No components have migrated despite the absence of adjunct fixation mechanisms such as screws and flanges. The pressfit achieved with the roughened hemispherical surface has been adequate, and the fixation with the two outrigger pegs appears to have been sufficiently stable to preserve the prosthetic stability and has resulted in successful anchorage of all the components. The results with femoral components are obviously related to technique. In a few early cases when undersized prostheses were used, loosening occurred, and four of these components advanced to detectable loosening. One of these components was revised since this analysis. Attention to detail with maximal filling of the proximal femur apparently led to improved results, with successful anchorage in all subsequent implantations. The application of the dimensional analysis before surgery may indicate those cases in which a tight fitting metaphysis cannot be achieved. In elderly patients who have osteoporotic bone, a substantial mismatch exists between the size of the metaphysis and the diaphysis, and it may be advisable to continue with cement in these cases. By applying the dimensional analysis to preoperative templating, the surgeon may be sufficiently informed to know that a tight fit can be achieved at surgery. No catastrophic failures have occurred. If loosening does occur because of undersizing of the prosthesis, the process appears to be gradual and, although associated with pain, does not result in sudden failure. Despite the prosthesis not being anchored by cement or collar, no sudden subsidence of the components has resulted. Patients' clinical performance has been somewhat slower when compared to cemented series. Performance seems to accelerate once weight bearing occurs, however, and after 2 years no difference exists between this series and a corresponding cemented series. Noncemented total hip arthroplasty appears to offer as good if not better results than cemented total hip arthroplasty, if performed correctly and in the appropriate patient. Successful outcome depends greatly on technique, but when technically adequate implantation has been performed, the results have been gratifying.(ABSTRACT TRUNCATED AT 400 WORDS)

A ten-year follow-up of one hundred consecutive Müller curved-stem total hip-replacement arthroplasties.

One hundred consecutive Müller curved-stem total hip replacements were reviewed ten years after operation. Twenty patients with twenty-two arthroplasties had died within the ten-year period without having a revision, and twenty-five arthroplasties had been revised for various reasons. Of the remaining fifty-three arthroplasties, thirty-five were classified as good or excellent, with Harris hip scores of 80 points or higher, and eighteen were classified as poor or fair, with scores lower than 80 points. Follow-up radiographs, made for all but six of the fifty-three hips at ten years, showed a 23 per cent incidence of migration of the acetabular component and a 28 per cent incidence of migration of the femoral component. In addition, there was a 15 per cent incidence of bone resorption in the proximal end of the femur without migration of the femoral component and a 4 per cent incidence of osteolytic defects about the femoral component, also without migration. Combining the radiographically loose replacement (migration) with the clinically loose ones (revised), the over-all incidence of aseptic loosening was 29 per cent for the acetabular component and 40 per cent for the femoral component. There was a positive correlation between the incidence of loosening of the femoral component and younger age, heavier weight, male sex, unilateral hip disease, a wide femoral canal, and varus position of the femoral component, whereas the incidence of loosening of the acetabular component was increased only in association with older age. The rate of loosening of the femoral component appeared to be higher during the early follow-up period and to decrease with time, while the rate of loosening of the acetabular component appeared to be lower during the early follow-up period but to increase with time.

Geometric total knee replacement: an eight year experience at the new England baptist hospital.

Total knee arthoplasty has been accepted as a valuable adjunct in the treatment of knees severely compromised by disease or trauma. One hundred nine geometric total knee replacements were reviewed to determine the efficacy of the device in the relief of pain, the correction of deformity and instability, and the restoration of functional motion in the diseased knee.1.