We investigated the wear characteristics and clinical performance of four different total hip joint articulations in 114 patients. Wear and migration was measured by roentgenstereophotogrammetric analysis at five years or at the last follow-up. The mean annual wear was 0.11 mm for a stainless steel/Enduron articulation, 0.34 mm for stainless steel/Hylamer cup, 0.17 mm for zirconium oxide ceramic/Enduron and 0.40 mm for zirconium oxide ceramic/Hylamer. The difference between the groups was significant (p < 0.008) except for stainless steel/Hylamer vs zirconium oxide ceramic/Hylamer (p = 0.26). At present, 12 patients have undergone a revision procedure, four at five years and eight thereafter. No patient who received a stainless steel/Enduron articulation at their primary replacement required revision. Conflicting results have been reported about the performance of the zirconium oxide ceramic femoral head, but our findings suggest that it should not be used with a polymethylmethacrylate acetabular component. Hylamer has already been withdrawn from the market

We have reviewed 97 consecutive primary hip replacements with a cemented femoral component and a porous-ingrowth acetabular component at a minimum five-year follow-up (average 6.5 years). The average Harris hip score was 93, and 85 hips had no pain or only slight pain. There had been no deterioration in the results since the two-year follow-up. The hybrid hip is successful for up to eight years and appears to be suitable for many patients. Long-term femoral fixation has been shown to improve with second-generation cementing techniques and in this series was excellent with third-generation techniques, in that only one stem was revised for loosening. No cementless acetabular component was revised for loosening

Aims

The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance.

We evaluated the concentrations of chromium and cobalt ions in blood after metal-on-metal surface replacement arthroplasty using a wrought-forged, high carbon content chromium-cobalt alloy implant in 64 patients. At one year, mean whole blood ion levels were 1.61 μg/L (0.4 to 5.5) for chromium and 0.67 μg/L (0.23 to 2.09) for cobalt. The pre-operative ion levels, component size, female gender and the inclination of the acetabular component were inversely proportional to the values of chromium and/or cobalt ions at one year postoperatively. Other factors, such as age and level of activity, did not correlate with the levels of metal ions. We found that the levels of the ions in the serum were 1.39 and 1.37 times higher for chromium and cobalt respectively than those in the whole blood. The levels of metal ions obtained may be specific to the hip resurfacing implant and reflect its manufacturing process

This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading. A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12). The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur. This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading

We describe two cases of fracture of Corin Taper-Fit stems used for cement-in-cement revision of congenital dysplasia of the hip. Both prostheses were implanted in patients in their 50s, with high offsets (+7.5 mm and +3.5 mm), one with a large diameter (48 mm) head and one with a constrained acetabular component. Fracture of the stems took place at nine months and three years post-operatively following low-demand activity. Both fractures occurred at the most medial of the two stem introducer holes in the neck of the prosthesis, a design feature that is unique to the Taper-Fit stem. We would urge caution in the use of these particular stems for cement-in-cement revisions

Twenty patients were examined by standard radiography and roentgen stereophotogrammetric analysis (RSA) during a two-year period after total hip arthroplasty. Eleven of the acetabular components migrated cranially and three femoral components migrated distally. This migration was most rapid during the first four months after operation. Our findings support the possibility that mechanical loosening is initiated by thermal injury during polymerisation of the cement; the less frequent migration of the metallic femoral component compared with the polyethylene acetabular component may be because the metal acts as a heat sink. Standard radiographs were inadequate for assessment of early mechanical loosening, whereas RSA could reveal migration within four months of the arthroplasty

Aims

The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs).

We compared the radiographic results of secondary total hip replacements, 99 following failed uncemented hemiarthroplasties and 21 following failed mould arthroplasties, with those of 825 primary cemented total hip replacements. The probability of occurrence of a number of radiological changes over time was calculated using survival analysis. The mean follow-up was 7.6 years (range one month to 20 years). The performance of the secondary total hip replacements varied with the preceding implant and was different for acetabular and femoral components. The incidence of radiological loosening was higher for femoral components implanted after failed hemiarthroplasties and for acetabular components after failed mould arthroplasties. However, the incidence of continuous radiolucent lines was lower for the acetabular components of converted hemiarthroplasties than for the primary replacements

Aims

Dual mobility (DM) implants have been shown to reduce the dislocation rate after total hip arthroplasty (THA), but there remain concerns about the use of cobalt chrome liners inserted into titanium shells. The aim of this study was to assess the clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) at mid-term follow-up in young, active patients receiving a modular DM THA.

Aims

The aim of this study was to evaluate the performance of first-generation annealed highly cross-linked polyethylene (HXLPE) in cementless total hip arthroplasty (THA).

Aims

Proximal femoral endoprosthetic replacements (PFEPRs) are the most common reconstruction option for osseous defects following primary and metastatic tumour resection. This study aimed to compare the rate of implant failure between PFEPRs with monopolar and bipolar hemiarthroplasties and acetabular arthroplasties, and determine the optimum articulation for revision PFEPRs.

We have studied the influence of weight-bearing on the measurement of wear of the polyethylene acetabular component in total hip arthroplasty using two techniques. The measured vertical wear was significantly greater when radiographs were taken weight-bearing rather than with the patient supine (p = 0.001, method 1; p = 0.007, method 2). Calculations of rates of linear wear of the acetabular component were significantly underestimated (p < 0.05) when radiographs were taken supine. There are two reasons for this. First, a change in pelvic orientation when bearing weight ensures that the thinnest polyethylene is brought into relief, and secondly, the head of the femoral component assumes the position of maximal displacement along its wear path. Interpretation of previous studies on both linear and volumetric polyethylene wear in total hip arthroplasty should be reassessed in the light of these findings

We have reviewed the rate of revision of fully cemented, hybrid and uncemented primary total hip replacements (THRs) registered in the New Zealand Joint Registry between 1999 and December 2006 to determine whether there was any statistically significant difference in the early survival and reason for revision in these different types of fixation. The percentage rate of revision was calculated per 100 component years and compared with the reason for revision, the type of fixation and the age of the patients. Of the 42 665 primary THRs registered, 920 (2.16%) underwent revision requiring change of at least one component. Fully-cemented THRs had a lower rate of revision when considering all causes for failure (p < 0.001), but below the age of 65 years uncemented THRs had a lower rate (p < 0.01). The rate of revision of the acetabular component for aseptic loosening was less in the uncemented and hybrid groups compared with that in the fully cemented group (p < 0.001), and the rate of revision of cemented and uncemented femoral components was similar, except in patients over 75 years of age in whom revision of cemented femoral components was significantly less frequent (p < 0.02). Revision for infection was more common in patients aged below 65 years and in cemented and hybrid THRs compared with cementless THRs (p < 0.001). Dislocation was the most common cause of revision for all types of fixation and was more frequent in both uncemented acetabular groups (p < 0.001). The experience of the surgeon did not affect the findings. Although cemented THR had the lowest rate of revision for all causes in the short term (90 days), uncemented THR had the lowest rate of aseptic loosening in patients under 65 years of age and had rates comparable with international rates of aseptic loosening in those over 65 years

Although the technique of autogenous acetabular bone grafting has been widely used to augment containment of the acetabulum in total hip arthroplasty (THA) for developmental dysplasia, the role of this technique in improving long-term results remains controversial. We present the long-term results of cemented THA with acetabular bone grafting in 112 patients (133 hips) in order to clarify the factors which affect the outcome. The mean follow-up was for 12.3 years (8 to 24). Kaplan-Meier survivorship analysis predicted a rate of survival of the acetabular component at 15 years of 96% (95% confidence interval (CI) 92 to 99) with revision for aseptic loosening as the endpoint, and of 75% (95% CI 65 to 85) when radiological loosening was used. Parametric survivorship analysis using the Cox proportional-hazards model indicated that trochanteric nonunion, lateral placement of the socket, and delayed trabecular reorientation of the bone graft were risk factors for loosening of the acetabular component. Our findings have shown that autologous acetabular bone grafting is of value for long-term success provided that the risk factors are reduced

We have made a retrospective review of 185 cemented Charnley total hip arthroplasties performed between 1970 and 1974 to determine the relationships between radiological variables and failure of the femoral and acetabular components. We measured the acetabular wear, the orientation of the cup, the thickness and consistency of acetabular and femoral cement mantles, radiolucency and femoral alignment. The mean follow-up was for 11.7 years. Femoral loosening was demonstrable radiologically in 15 hips (8.1%), ten (5.4%) of which were revised during the period of follow-up. Only when the first postoperative radiograph showed a thin cement mantle in Gruen zone 5 was there a significant association with failure of the femoral component. There were 12 loose acetabular components (6.5%), nine (4.8%) of which were revised. When the initial radiograph after operation showed radiolucency in DeLee and Charnley zone 1, the incidence of acetabular loosening was 28.21%. If such radiolucency was not present, the incidence of acetabular loosening was only 0.69%. Our findings emphasise the importance of careful cementing

The outcome at ten years of 100 Freeman hip stems (Finsbury Orthopaedics, Leatherhead, United Kingdom) retaining the neck with a proximal hydroxyapatite coating in a series of 52 men (six bilateral) and 40 women (two bilateral), has been described previously. None required revision for aseptic loosening. We have extended the follow-up to 20 years with a minimum of 17 years. The mean age of the patients at total hip replacement was 58.9 years (19 to 84). Six patients were lost to follow-up, but were included up to their last clinical review. A total of 22 patients (22 hips) had died, all from causes unrelated to their surgery. There have been 43 re-operations for failure of the acetabular component. However, in 38 of these the stem was not revised since it remained stable and there was no associated osteolysis. Two of the revisions were for damage to the trunnion after fracture of a modular ceramic head, and in another two, removal of the femoral component was because of the preference of the surgeon. In all cases the femoral component was well fixed, but could be extracted at the time of acetabular revision. In one case both components were revised for deep infection. There has been one case of aseptic loosening of the stem which occurred at 14 years. This stem had migrated distally by 7.6 mm in ten years and 8.4 mm at the time of revision at which stage it was found to be rotationally loose. With hindsight this component had been undersized at implantation. The survivorship for the stem at 17 years with aseptic loosening as the endpoint was 98.6% (95% confidence interval 95.9 to 100) when 62 hips were at risk. All remaining stems had a satisfactory clinical and radiological outcome. The Freeman proximally hydroxyapatite-coated femoral component is therefore a dependable implant and its continued use can be recommended

We reviewed a consecutive series of 241 uncemented, porous-coated anatomic (PCA) hip replacements at an average follow-up of five years (2 to 9). Of these, 32 had failed (13%), 26 at the acetabular component (11%) and six at the femoral component (2%). Acetabular failure was associated with local osteolysis and excessive polyethylene wear in 20 cases: in these histological examination showed giant macrophages incorporating numerous particles of high-density polyethylene. The femoral failures were related to a poor intramedullary fit with subsequent subsidence. Using the recommendation for revision as the end point, the cumulative survival rate for prostheses was 91% at six years (95% CI +/- 6%), 73% (+/- 11%) at seven years, and 57% (+/- 20%) at eight years. The result of uncemented PCA hip replacement is satisfactory up to six years, but then increasing failure of the acetabular component appears to be due to polyethylene wear, leading to osteolysis, loosening and component migration. At first, failure is often asymptomatic; routine follow-up of uncemented hip replacement is essential, especially after five years