Polyethylene wear in prosthetic hips with loose components.

We measured in vivo polyethylene wear of acetabular cups in 74 patients (83 hips) with Charnley total hip arthroplasties (THA), revised because of aseptic loosening of either the acetabular or femoral component. We analyzed conventional pelvic radiographs of 42 THAs before revision due to loose acetabular components alone and 41 THAs before revision due to loose femoral components alone. The THAs were revised after 10 to 26 years.

Conversion of a fused hip to total hip arthroplasty.

Background: Arthrodesis of the hip remains a viable treatment for severe unilateral arthritis after traumatic injury or infection in a young but otherwise healthy individual. The goal of the present study was to review the long-term clinical and radiographic results after conversion of a fused hip to a total hip arthroplasty and to identify the risk factors that would lead to a higher rate of failure.

Methods: We performed a retrospective review of the charts and radiographs of 187 patients (208 hips) who had conversion of a fused hip to a total hip arthroplasty.

Total hip arthroplasty in ankylosing spondylitis: an analysis of 181 hips.

The results of cemented total hip arthroplasty (THA) in patients with ankylosing spondylitis were studied to determine the utility of THA for these patients. A total of 103 patients with ankylosing spondylitis underwent 181 THAs; 72 patients (69.9%) had bilateral surgery.

The relationship of foot and ankle movements to venous return in the lower limb.

We have studied the relationship between movements of the foot and ankle and venous blood flow from the lower limb using colourflow Duplex ultrasound to determine the optimum type of exercise for promoting venous return. Studies of both active and passive movements were carried out on 40 limbs in 20 subjects (18 men; 2 women), with a median age of 27 years (20 to 54). We assessed ankle dorsiflexion and plantar flexion, subtalar inversion and eversion, and a combination of all movements.

Comparison of the Wrightington FC hip with the Charnley low-friction arthroplasty. 10- to 15-year results and survival analysis.

Between 1981 and 1986 two groups of patients received either Charnley low-friction arthroplasties or the Wrightington Frusto-Conical hip replacement with otherwise identical management before and after operation. There were 260 consecutive replacements in 215 patients in the first group and 260 consecutive procedures in 211 patients in the second. Both components of each design were cemented and featured a 22.

Migration and wear of long-term successful Charnley total hip replacements.

We analysed in-vivo migration and wear over a long period of all-polyethylene acetabular cups which had not been affected by mechanical loosening. The selection criteria of regular radiological follow-up, good clinical outcome (Charnley score of 5 or 6), continued walking without crutches and no radiological signs of loosening of the acetabular cups were fulfilled by 25 Charnley total hip arthroplasties. Mean migration, measured by the Nunn method, was 0.

Nonsurgical management of supracondylar fracture above total knee arthroplasty. Still the nineties option.

Supracondylar fracture of the femur above a total knee arthroplasty has been reported to occur in 0.3-2.5% of all cases.

Total hip arthroplasty for congenital dysplasia or dislocation of the hip. Survivorship analysis and long-term results.

Two hundred and thirty-two total hip replacements with cement were performed between 1965 and 1987 in 190 patients who had osteoarthrosis secondary to acetabular dysplasia resulting from congenital dysplasia or dislocation of the hip. Forty-nine patients (fifty hips) who died or who did not have at least three years of clinical and radiographic follow-up were excluded; therefore, the study comprised 141 patients (182 hips), 125 of whom were women and sixteen of whom were men. The mean age at the time of the operation was 42.

Total knee arthroplasty after patellectomy.

We compared the outcome of total knee arthroplasty in 19 patients who had had previous patellectomy with the results in a matched series of arthroplasties performed on knees in which the patella was intact. The mean follow-up was 63 months (21 to 114). In the study group, the outcome was poor in five patients.

Muscle strength following total hip arthroplasty. A comparison of trochanteric osteotomy and the direct lateral approach.

Twenty-seven patients who had hip arthroplasty operated on with trochanteric osteotomy were compared with 54 patients when the direct lateral approach was used. The strength of the hip abductors, adductors, extensors, and flexors were measured at least 2 years following surgery. The strength of these muscle groups recovered to the same level as those on the nonoperated side, and there was no significant difference between the two groups of patients.

Long-term results of Charnley low-friction arthroplasty in young patients.

We report the long-term outcome of 218 Charnley low-friction arthroplasties in 141 patients who were 40 years old or younger at the time of surgery. The minimum follow-up was ten years with a mean of 16 years. The probability of the femoral component surviving 20 years was 86% and of the acetabular component, 84%.

Aseptic loosening of the femoral component in cemented total hip replacement.

The purpose of this study was to identify factors which predispose to aseptic loosening of the femoral component in cemented total hip replacement. Its design was based on rigid selection criteria, so that successful and loose replacements which employed the same surgical technique were compared. Measurements of patient anatomy and of the insertion of the femoral component were made, by an accurate computer technique, on initial post-operative radiographs.

Polyethylene wear in unicondylar knee prostheses. 106 retrieved Marmor, PCA, and St Georg tibial components compared.

106 unicondylar knee replacement tibial components were retrieved and analyzed for the amount and type of polyethylene wear. Three different designs were retrieved which had essentially the same femorotibial conformity. Each design showed a characteristic failure pattern.

Bending and fracture of the femoral component in cemented total hip replacement.

A computer method was used to make 41 measurements on the geometry of insertion of the femoral component in 200 Charnley total hip replacements. Surgery had been performed at least 12 years before, giving results which were classified as: success (90); fracture (56); or loose (54), according to rigid selection criteria. Fracture was associated with heavier patients in which there was poor proximal fixation of the femoral component but adequate distal fixation.

The dominance of cyclic sliding in producing wear in total knee replacements.

From a literature survey, it was evident that a wide variety of kinematic conditions occur at the femoral-tibial bearing surfaces, including various degrees of rolling and sliding. A test machine was constructed to reproduce these conditions, applied to spherical-ended metal 'femoral' components acting on a flat polyethylene 'tibial' plateau. The load was cyclic at 2.

Measurement of hip prostheses using image analysis. The maxima hip technique.

A computer-based image analysis system has been developed as a research tool in total hip replacement. The system has been programmed to take multiple measurements from coronal plane radiographs. Poor quality radiographic images can be enhanced and standardised.

Segmental fracture of the femoral stem of a low-friction arthroplasty. A case report.

Fracture of the femoral stem of a cemented hip arthroplasty is a well documented complication. However, double or segmental fracture is extremely rare, with only one other case appearing in the literature. The authors report a second case and discuss its etiology.

Prosthetic hip failure: retrospective radiograph image analysis of the acetabular cup.

A method has been developed for quantifying movement and wear of the acetabular component (cup) of total hip replacements (THR) from routine postoperative and review radiographs. The method uses both interactive and automatic computer image analysis techniques. Dimensions of the prosthesis are used to scale the measurements and so overcome variation in radiographic alignment.

Bone grafting for protrusio acetabuli during total hip replacement. A review of the Wrightington method in 61 hips.

Total hip replacement has been very successful in patients with painful, stiff hips associated with protrusio acetabuli, but the heat of polymerisation of methylmethacrylate cement may cause necrosis of the thin medial wall with consequent danger of migration of the cup. Since 1968 at Wrightington, thin slices of the head of the femur have been used as bone grafts to reinforce the acetabulum. We have reviewed 61 hips in 51 patients at an average of 4 years 3 months after operation.

Conversion of hip fusion to Charnley low-friction arthroplasty.

Spontaneous fusion of the hip following infection or surgical procedures can result in deformity that causes degenerative change in the associated joints. Loss of function can cause pain in adjacent joints. Conversion of hips fused in a deformed position to low-friction arthroplasty reduces shearing strain and improves walking function.

Complications of the Attenborough knee replacement.

Of a consecutive series of 144 Attenborough knee replacements, 107 were re-examined between two and six years after operation and revealed a high incidence of complications. Wound problems were common and led to deep infection in four knees. When a patellar implant was used fracture of the patella followed in 17.

Failure of one design of surface replacement knee arthroplasty due to loosening deformation and wear of the plastic femoral component.

Twenty four knee prosthesis femoral and tibial components of the 'load angle inlay' design, removed for loosening and pain were examined in the scanning electron microscope, light microscope, and volume loss measured using a simple gauge. In all cases the deformation of the plastic (femoral) component was seen both by increase in the curvature of the inner surface and wear usually on the edge of the bearing surface. Two pairs were subluxed prior to removal from the patient and these not only produced gross deformation of the plastic components, but maximum volume loss of the components examined; the knees exhibited gross instability.