A retrospective review of 148 consecutive porous-coated hip arthroplasties (PCA) showed an incidence of thigh pain of 13% one year after surgery, and 22% at two years. Positive correlations were made with femoral stem subsidence (greater than 2 mm) and with distal periosteal and endosteal bone formation. No positive correlations were made with parameters of bone quality or component fit. Resolution of pain occurred in one-third and an anti-inflammatory agent produced partial relief in two-thirds of the patients. We conclude that thigh pain is secondary to stem instability with distal stress transfer in the absence of stable proximal fixation

We examined 59 cemented high density polyethylene sockets removed at revision hip arthroplasty. Of these 19 showed areas of wear between the outside of the socket and the acetabular bone. This was associated with lack of acrylic cement in those areas and was also related to the depth of the wear on the articulating surface of the socket. It is suggested that, in some cases, changes at the bone-cement junction are secondary to socket loosening and abrasion against the bone of the acetabulum, rather than to particles migrating from the metal-polyethylene interface. It is therefore important that impingement of the neck of the femoral stem on the edge of the cup be avoided and that, when the socket is inserted, it is not in direct contact with the bone

Review of the radiographs of 882 consecutive metal-to-polyethylene hip replacements after a mean follow-up of 6.8 years showed 72 cases (8%) of aseptic femoral loosening, all of which showed a lucent zone or black line between metal and cement. In 97% of the series this appeared within two years of the arthroplasty. Progress of loosening was unpredictable and only 24% had significant symptoms. Improved technique with methylmethacrylate cement in Stanmore prostheses had reduced loosening after two years from 7.9% to 0.4%. Methods of detection of early loosening are discussed

We selected randomly a consecutive series of 162 patients requiring hip replacement to receive either a cementless, hemispherical, modular, titanium acetabular cup or a cemented, all-polyethylene cup. These replacements were performed by two surgeons in four general hospitals. The same surgical technique was used and a 26 mm metal-head femoral component was used in every case. After exclusions, 115 hips were studied for differences in rates of wear and osteolysis. The mean clinical follow-up was eight years and the mean radiological follow-up, 6.5 years. The cementless cups wore at a mean rate of 0.15 mm per year and the cemented cups at 0.07 mm per year. This difference was significant (p < 0.0001). Our findings in this mid-term study suggest that cementless cups wear more than cemented cups

A study of excision arthroplasty (Girdlestone's pseudarthrosis) for infected total hip replacements is presented. Twenty-two patients were reviewed with a minimum follow-up of one year. Reduction in pain was significant but the functional results were poor. Factors contributing to poor function were old age, poor medical condition and arthritis of the contralateral hip; these were in addition to the gross instability resulting from the pseudarthrosis. The patients were easily fatigued and dependent on external supports; calipers were found to be unacceptable. The symptoms after excision arthroplasty are compared with those before the original hip replacement

A total of 138 revision hip arthroplasties in 134 patients, all operated upon by one surgeon, were followed for an average of 7.4 years. The overall results were reasonable, with good to excellent Mayo hip scores in 62% and little or no pain in 86%. These results were independent of body weight, age, primary diagnosis and type of arthroplasty used. The incidence of radiological loosening was alarming, though comparable to that found in other series. Our findings indicate that it may be wise to replace both components even when, after careful assessment before and during operation, one of them seems to be securely fixed

Aims

Cardiac magnetic resonance (CMR) was used to assess whether cardiac function or tissue composition was affected in patients with well-functioning metal-on-metal hip resurfacing arthroplasties (MoMHRA) when compared with a group of controls, and to assess if metal ion levels correlated with any of the functional or structural parameters studied.

The serum liver enzyme levels of 40 consecutive patients before and after cemented hip replacement were compared with a control group having operation without use of cement. Serum gammaglutamyl transferase (SGGT) was abnormally raised, for more than four days, in 12 of the 40 patients (32%) in whom bone cement was used, compared with one of the 36 control patients. The changes in SGGT levels after operation correlated with the weight of cement used (r = 0.66, p less than 0.001), but there was return to normal levels in all patients. A temporary dose-related effect of bone cement on liver function is demonstrated

We measured the levels of cobalt and chromium in the serum in three groups of patients after uncemented porous-coated arthroplasty. Group 1 consisted of 14 consecutive patients undergoing revision for aseptic loosening. Group 2 comprised 14 matched patients in whom the arthroplasty was stable and group 3 was 14 similarly matched patients with arthritis awaiting hip replacement. Specimens were analysed using atomic absorption spectrophotometry. Aseptic loosening of a component resulted in a significant elevation of serum cobalt (p < 0.05), but not of serum chromium. The relative risk of a component being loose, if the patient had a serum cobalt greater than 9.0 nmol/l, was 2.8

The Control of Infection Committee at a specialist orthopaedic hospital prospectively collected data on all episodes of bacteriologically-proven deep infection arising after primary hip and knee replacements over a 15-year period from 1987 to 2001. There were 10 735 patients who underwent primary hip or knee replacement. In 34 of 5947 hip replacements (0.57%) and 41 of 4788 knee replacements (0.86%) a deep infection developed. The most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. Of the infecting organisms, 72% were sensitive to routine prophylactic antimicrobial agents. Of the infections, 29% (22) arose in the first three months following surgery, 35% between three months and one year (26), and 36% (27) after one year. Most cases were detected early and treated aggressively, with eradication of the infection in 96% (72). There was no significant change in the infection rate or type of infecting micro-organism over the course of this study. These results set a benchmark, and importantly emphasise that only 64% of peri-prosthetic infections arise within one year of surgery. These results also illustrate the advantages of conducting joint replacement surgery in the isolation of a specialist hospital

We investigated the effect of the Birmingham hip resurfacing (BHR) arthroplasty on the bone mineral density (BMD) of the femur. A comparative study was carried out on 26 hips in 25 patients. Group A consisted of 13 patients (13 hips) who had undergone resurfacing hip arthroplasty with the BHR system and group B of 12 patients (13 hips) who had had cementless total hip arthroplasty with a proximal circumferential plasma-spray titanium-coated anatomic Ti6A14V stem. Patients were matched for gender, state of disease and age at the time of surgery. The periprosthetic BMD of the femur was measured using dual-energy x-ray absorptiomentry of the Gruen zones at two years in patients in groups A and B. The median values of the BMD in zones 1 and 7 were 99% and 111%, respectively. The post-operative loss of the BMD in the proximal femur was significantly greater in group B than in group A. These findings show that the BHR system preserves the bone stock of the proximal femur after surgery

We present the results of 506 consecutive Howse hip arthroplasties with a minimum follow-up of 10 years. The mortality within one month of surgery was 0.79%. The early dislocation rate was 1.38%, two hips requiring revision. Nine hips developed deep sepsis (1.78%), eight of which required revision. At 10 years 42 hips (8.3%) had required revision, including 14 with aseptic acetabular loosening and 11 with femoral stem fractures. We feel that as judged by the dislocation rate and the need for subsequent revision, the Howse arthroplasty is an acceptable form of total hip replacement, particularly in the older patient and in those requiring total replacement for femoral neck fractures

A retrospective study of 44 diabetic patients who, between them, had 62 Charnley low-friction arthroplasties, showed a superficial-infection rate of 9.7 per cent and a deep-infection rate of 5.6 per cent. All the operations were carried out in the Charnley clear-air enclosure and prophylactic antibiotics were not used. A statistically significant increase in the overall rate of infection was found in diabetic patients when compared with non-diabetic osteoarthritic patients (P less than 0.001) and rheumatoid patients (P less than 0.01). Hence it is suggested that in diabetic patients there may well be a place for prophylactic antibiotics in hip replacement surgery in addition to the use of the clean-air enclosure

Our aim was to analyse the influence of the size, shape and number of particles on the pathogenesis of osteolysis. We obtained peri-implant tissues from 18 patients having revision surgery for aseptically loosened Freeman total knee replacements (10), Charnley total hip replacements (3) and Imperial College/London Hospital double-cup surface hip replacements (5). The size and shape of the polyethylene particles were characterised using SEM and their concentration was calculated. The results were analysed with reference to the presence of radiological osteolysis. The concentration of polyethylene particles in 6 areas with osteolysis was significantly higher than that in 12 areas without osteolysis. There were no significant differences between the size and shape of the particles in these two groups. We conclude that the most critical factor in the pathogenesis of osteolysis is the concentration of polyethylene particles accumulated in the tissue

Using a regional arthroplasty register, we assessed the outcome, at five years, of 1198 primary Charnley total hip replacements (THRs) undertaken across a single health region in England in 1990. An independent clinical and radiological assessment was completed for 497 operations, carried out in 18 different hospitals, under the care of 56 consultants and by differing grades of surgeon. The overall number of failures in this group was 44 (8.9%). We found that the risk of failure in patients operated on by a consultant whose firm carried out 60 or more THRs in 1990 was 25% of that of patients under the care of a consultant whose firm undertook less than 30, adjusting for a number of patient, surgeon and hospital characteristics (16% v 4%; p < 0.001 for linear trend). Our study shows that the early outcome of hip replacement surgery varies with the number of replacements undertaken by the consultant firm. A national arthroplasty register would be a convenient source for such data

The purpose of this study was to determine the biological effects of the elastic modulus of the femoral stem in canine hip arthroplasty. Cementless total hip arthroplasty was performed in 12 dogs, six had a low elastic modulus polyacetal resin stem and six had a high modulus stainless steel stem. The components were otherwise similar. At six and 12 months after operation, radiographic and histomorphometric analysis showed that those with steel implants had more cortical porosity than did the other group (p less than 0.01). We suggest that the elastic modulus of the implant is an important factor in controlling cortical bone resorption. A low modulus femoral prosthesis can significantly decrease bone resorption which might otherwise eventually lead to implant failure

There are many studies of long-term recovery from major joint arthroplasty, but little is known about the first days and weeks after operation. We measured function, emotional state and life evaluation before arthroplasty and at seven and 50 days after in a consecutive series of 40 hip and 23 knee replacements. Pain was relieved significantly at seven days after hip arthroplasty and even more at 50 days. In knee patients, pain relief was modest and was not apparent until 50 days. Functional ability was much improved by 50 days in hip patients, but hardly changed in knee patients. Positive mood and life satisfaction did not improve in either group. Our findings will help with more accurate information for patients before operation and also in judging the rate of recovery