We studied survival to 38 years after Charnley low-friction arthroplasty of the hip. We used revision as an end-point, while adopting a policy of regular follow-up and early revision for radiological changes alone if indicated.

Between November 1962 and June 2005, 22 066 primary low-friction arthroplasties (17 409 patients) had been performed at Wrightington Hospital by more than 330 surgeons. By June 2006, 1001 (4.5%) hips had been revised and 1490 patients (2662 hips, 12%) had died. At 31 years, where a minimum of 40 hips were still attending follow-up, survival with revision for infection as an endpoint was 95%, for dislocation 98%, for a fractured stem 88.6%, for a loose stem 72.5% and for a loose acetabular component 53.7%. Wear and loosening of the ultra-high-molecular-weight polyethylene acetabular component were the main long-term problems.

We conclude that regular follow-up after hip replacement is essential and that all operative findings should be recorded at revision.

We have evaluated the quality of life and functional outcome after unilateral primary total hip replacement (THR). Between 5 January 1998 and 31 July 2000, we recruited a consecutive series of 627 patients undergoing this procedure and investigated them prospectively. Each was assessed before operation and reviewed after six months, 18 months, three years and five years. The Short Form-36 Health Survey (SF-36) and Harris Hip scores were evaluated at each appointment.

All dimensions of the SF-36 except for mental health and general health perception, improved significantly after operation and this was maintained throughout the follow-up. The greatest improvement was seen at the six-month assessment. On average, women reported lower SF-36 scores pre-operatively, but the gender difference did not continue post-operatively. The Harris Hip scores improved significantly after operation, reaching a plateau after 18 months. The improved quality of life was sustained five years after THR.

We investigated 219 revisions of total hip replacement (THR) in 211 patients using a collarless double-taper cemented femoral component. The mean age of the patients was 72 years (30 to 90). The 137 long and 82 standard length stems were analysed separately. The mean follow-up was six years (2 to 18), and no patient was lost to follow-up.

Survival of the long stems to re-revision for aseptic loosening at nine years was 98% (95% confidence interval (CI) 94 to 100), and for the standard stems was 93% (95% CI 85 to 100). At five years, one long stem was definitely loose radiologically and one standard stem was probably loose. Pre-operative femoral bone deficiency did not influence the results for the long stems, and corrective femoral osteotomy was avoided, as were significant subsidence, major stress shielding and persistent thigh pain.

Because of these reliable results, cemented long collarless double-taper femoral components are recommended for routine revision THR in older patients.

Little is known about the efficacy of graduated compression stockings in preventing venous thromboembolism after hip surgery. We conducted a prospective, randomised single-blind study to determine whether the addition of compression stockings to fondaparinux conferred any additional benefit.

The study included 874 patients, of whom 795 could be evaluated (400 in the fondaparinux group and 395 in the fondaparinux plus compression stocking group). Fondaparinux was given post-operatively for five to nine days, either alone or combined with wearing stockings, which were worn for a mean 42 days (35 to 49).

The study outcomes were venous thromboembolism, or sudden death before day 42. Duplex ultrasonography was scheduled within a week of day 42. Safety outcomes were bleeding and death from venous thromboembolism.

The prevalence of deep-vein thrombosis was similar in the two groups 5.5% (22 of 400) in the fondaparinux group and 4.8 (19 of 395) in the fondaparinux plus stocking group (odds ratio 0.88, 95% confidence interval 0.46 to 1.65, p = 0.69). Major bleeding occurred in only one patient.

The addition of graduated compression stockings to fondaparinux appears to offer no additional benefit over the use of fondaparinux alone.

We have reviewed 54 patients who had undergone 61 total hip replacements using bulk femoral autografts to augment a congenitally dysplastic acetabulum. There were 52 women and two men with a mean age of 42.4 years (29 to 76) at the time of the index operation. A variety of different prostheses was used: 28 (45.9%) were cemented and 33 (54.1%) uncemented. The graft technique remained unchanged throughout the series.

Follow-up was at a mean of 8.3 years (3 to 20). The Hospital for Special Surgery hip score improved from a mean of 10.7 (4 to 18) pre-operatively to a mean of 35 (28 to 38) at follow-up.

The position of the acetabular component was anatomical in 37 hips (60.7%), displaced less than 1 cm in 20 (32.7%) and displaced more than 1 cm in four (6.6%). Its cover was between 50% and 75% in 34 hips (55.7%) and less than 50% in 25 (41%). In two cases (3.3%), it was more than 75%.

There was no graft resorption in 36 hips (59%), mild resorption in 21 (34%) and severe resorption in four (6%).

Six hips (9.8%) were revised for aseptic loosening. The overall rate of loosening and revision was 14.8%. Overall survival at 8.3 years was 93.4%.

The only significant factor which predicted failure was the implantation of the acetabular component more than 1 cm from the anatomical centre of rotation of the hip.

The National Institute for Clinical Excellence (NICE) published the guidelines on the selection of prostheses for primary hip replacement in 2000. They supported the use of cemented hip prostheses to the exclusion of uncemented and hybrid implants. The information from the Trent (and Wales) Regional Arthroplasty Study has been examined to identify retrospectively the types of hip prostheses used between 1990 and 2005, and to assess the impact that the guidelines have had on orthopaedic practice.

The results show that the publication of the NICE guidelines has had little impact on clinical practice, with the use of uncemented prostheses increasing from 6.7% (137) in 2001 to 19.2% (632) in 2005. The use of hybrid prostheses has more than doubled from 8.8% (181) to 22% (722) of all hips implanted in the same period. The recommendations made by NICE are not being followed, which calls into question their value.

Transtrochanteric curved varus osteotomy was designed to avoid some of the disadvantages of varus wedge osteotomy, such as post-operative leg-length discrepancy. In this retrospective study we investigated the leg-length discrepancy and clinical outcome after transtrochanteric curved varus osteotomy undertaken in patients with osteonecrosis of the femoral head. Between January 1993 and March 2004, this osteotomy was performed in 42 hips of 36 patients with osteonecrosis of the femoral head. There were 15 males and 21 females with a mean age at surgery of 34 years (15 to 68). The mean follow-up was 5.9 years (2.0 to 12.5). The mean pre-operative Harris hip score was 64.0 (43 to 85) points, which improved to a mean of 88.7 (58 to 100) points at final follow-up. The mean varus angulation post-operatively was 25° (12° to 38°) and the post-operative mean leg-length discrepancy was 13 mm (4 to 25). The post-operative leg-length discrepancy showed a strong correlation with varus angulation (Pearson’s correlation coefficient; r = 0.9530, p < 0.0001), which may be useful for predicting the leg-length discrepancy which can occur even after transtrochanteric curved varus osteotomy.

We performed a three-year radiostereometric analysis (RSA) study of the Elite Plus femoral component on 25 patients undergoing primary total hip replacement. Additional assessments and measurements from standard radiographs were also made.

Subsidence of the stem occurred at the cement-stem interface. At 36 months the subsidence of the stem centroid was a mean of 0.30 mm (0.02 to 1.28), and was continuing at a slow rate. At the same time point, internal rotation and posterior migration of the femoral head had ceased. One stem migrated excessively and additional assessments suggested that this was probably due to high patient demand.

The failure rate of 4% in our study is consistent with data from arthroplasty registers but contrasts with poor results from another RSA study, and from some clinical studies. We believe that the surgical technique, particularly the use of high-viscosity cement, may have been an important factor contributing to our results.

We describe three cases of fracture of the titanium JRI-Furlong hydroxyapatite-ceramic (HAC)-coated femoral component. We have examined previous case reports of failure of this stem and conclude that fracture may occur in two places, namely at the neck-shoulder junction and at the conical-distal cylindrical junction. These breakages are the result of fatigue in a metallurgically-proven normal femoral component. All the cases of failure of the femoral component have occurred in patients with a body mass index of more than 25 in whom a small component, either size 9 or 10, had been used.

In patients with a body mass index above normal size 9 components should be avoided and the femoral canal should be reamed sufficiently to accept a large femoral component to ensure that there is adequate metaphyseal fixation.

We studied the medium-term outcome of the Bernese periacetabular osteotomy in 52 patients (58 hips) with symptomatic developmental dysplasia of the hip and a mean age of 37.6 years (13 to 48).

The operations were performed between 1993 and 2005 by the senior author with a mean follow-up of 66.7 months (13 to 153). There were 42 women (47 hips) and ten men (11 hips). Of these patients, 24 (30 hips) had an osteotomy on the right side and 22 (28 hips) on the left. Six patients had bilateral operations. The clinical outcome was assessed using the modified Merle d’Aubigne scale, and pre- and post-operative radiological evaluation using the modified Tonnis osteoarthritis score, the centre-edge angle, the acetabular index, the status of Shenton’s line, and the cross-over sign.

The mean centre-edge angle and the acetabular index were 14° (2° to 34°) and 23.6° (0° to 40°) before operation, and 36.6° (16° to 72°) and 7.9° (0° to 28°) after, respectively (p < 0.001, analysis of variance (ANOVA)). Shenton’s line was intact in 23 hips (39.6%) before operation and in 48 hips (82.8%) after. The cross-over sign was present in 31 hips (53.4%) before and in three hips (5.2%) after operation (p < 0.001, ANOVA). The total Merle d’Aubigne clinical score improved from a mean of 12.6 (9 to 15) to 16.0 (12 to 18) points (p < 0.001, ANOVA). Only four hips required subsequent total hip replacement.

Our results indicate that the Bernese periacetabular osteotomy provides good symptomatic relief for patients with little to no arthritis (Tonnis type 0 or 1) with an underlying deformity that can be corrected to a position of a stable, congruent hip joint.

Metal ions generated from joint replacements are a cause for concern. There is no consensus on the best surrogate measure of metal ion exposure. This study investigates whether serum and whole blood concentrations can be used interchangeably to report results of cobalt and chromium ion concentrations.

Concentrations of serum and whole blood were analysed in 262 concurrent specimens using high resolution inductively-coupled plasma mass-spectrometry. The agreement was assessed with normalised scatterplots, mean difference and the Bland and Altman limits of agreement.

The wide variability seen in the normalised scatterplots, in the Bland and Altman plots and the statistically significant mean differences between serum and whole blood concentrations suggest that they cannot be used interchangeably. A bias was demonstrated for both ions in the Bland-Altman plots. Regression analysis provided a possible conversion factor of 0.71 for cobalt and 0.48 for chromium. However, even when the correction factors were applied, the limits of agreement were greater than ±67% for cobalt and greater than ±85% for chromium, suggesting that serum and whole blood cannot be used interconvertibly. This suggests that serum metal concentrations are not useful as a surrogate measure of systemic metal ion exposure.

Femoroacetabular impingement is recognised as being a cause of labral tears and chondral damage. We report a series of five patients who presented with persistent pain in the hip after arthroscopy for isolated labral debridement. All five had a bony abnormality consistent with cam-type femoroacetabular impingement. They had a further operation to correct the abnormality by chondro-osteoplasty of the femoral head-neck junction. At a mean follow-up of 16.3 months (12 to 24) all had symptomatic improvement.

We analysed the results of different strategies in the revision of primary uncemented acetabular components reported to the Norwegian Arthroplasty Register. The aim was to compare the risk of further acetabular revision after isolated liner exchange and complete component revision. The results of exchanging well-fixed components were also compared with those of exchanging loose acetabular components. The period studied was between September 1987 and April 2005. The following groups were compared: group 1, exchange of liner only in 318 hips; group 2, exchange of well-fixed components in 398; and group 3, exchange of loose components in 933. We found that the risk of a further cup revision was lower after revision of well-fixed components (relative risk from a Cox model (RR) = 0.56, 95% confidence interval 0.37% to 0.87%) and loose components (RR = 0.56, 95% confidence interval 0.39% to 0.80%), compared with exchange of the liner in isolation. The most frequent reason for a further acetabular revision was dislocation, accounting for 61 (28%) of the re-revisions. Other reasons for further revision included pain in 27 (12%), loosening in 24 (11%) and infection in 20 (9%). Re-revisions because of pain were less frequent when complete component (fixed or loose) revision was undertaken compared with isolated exchange of the liner (RR = 0.20 (95% confidence interval 0.06% to 0.65%) and RR = 0.10 (95% confidence interval 0.03% to 0.30%), respectively). The risk of further acetabular revision for infection, however, did not differ between the groups.

In this study, exchange of the liner only had a higher risk of further cup revision than revision of the complete acetabular component. Our results suggest that the threshold for revising well-fixed components in the case of liner wear and osteolysis should be lowered.

Metal-on-metal bearings for total hip replacement (THR) are becoming increasingly popular. Improved wear characteristics mean that these articulations are being inserted into younger patients in the form of THR and resurfacing procedures. This has led to concerns regarding potential carcinogenicity because of the increased exposure to metal ions that the procedure brings.

We have studied the serum cobalt and chromium concentrations in patients who had primary, well-fixed Ring metal-on-metal THRs for more than 30 years. The levels of cobalt and chromium were elevated by five and three times, respectively compared with those in our reference groups. Metal-on-metal articulations appear to be the source of metal ions throughout the life of the prosthesis. In three patients who had undergone revision of a previous metal-on-metal THR to a metal-on-polyethylene replacement the levels of metal ions were within the normal range. The elevations of cobalt and chromium ions seen in our study were comparable with those in patients with modern metal-on-metal THRs.

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.

We studied prospectively the long-term results of the Charnley Elite-Plus femoral stem in 184 consecutive young patients (194 hips). There were 130 men and 54 women with a mean age of 49.1 years (21 to 60). The predominant diagnosis was osteonecrosis of the femoral head (63.6%, 117 patients). Clinical and radiological evaluation was undertaken at each follow-up. The mean follow-up was 11.2 years (10 to 12).

The mean pre-operative Harris hip score was 43.4 (12 to 49) which improved to 91 (59 to 100) at the final follow-up. The survival of the femoral stem at 12 years was 99% with revision as the end-point. The mean annual linear wear of the polyethylene liner was 0.17 mm (0.13 to 0.22). The prevalence of acetabular osteolysis was 10.8% (21 hips) and osteolysis of the calcar femorale 12.9% (25 hips).

A third-generation cementing technique, accurate alignment of the stem and the use of a 22 mm zirconia head were important factors in the prevention of aseptic loosening of the Elite Plus femoral stem in these high-risk young patients.

We have developed a CT-based navigation system using infrared light-emitting diode markers and an optical camera. We used this system to perform cementless total hip replacement using a ceramic-on-ceramic bearing couple in 53 patients (60 hips) between 1998 and 2001. We reviewed 52 patients (59 hips) at a mean of six years (5 to 8) postoperatively. The mid-term results of total hip replacement using navigation were compared with those of 91 patients (111 hips) who underwent this procedure using the same implants, during the same period, without navigation. There were no significant differences in age, gender, diagnosis, height, weight, body mass index, or pre-operative clinical score between the two groups. The operation time was significantly longer where navigation was used, but there was no significant difference in blood loss or navigation-related complications. With navigation, the acetabular components were placed within the safe zone defined by Lewinnek, while without, 31 of the 111 components were placed outside this zone. There was no significant difference in the Merle d’Aubigne and Postel hip score at the final follow-up. However, hips treated without navigation had a higher rate of dislocation. Revision was performed in two cases undertaken without navigation, one for aseptic acetabular loosening and one for fracture of a ceramic liner, both of which showed evidence of neck impingement on the liner. A further five cases undertaken without navigation showed erosion of the posterior aspect of the neck of the femoral component on the lateral radiographs. These seven impingement-related mechanical problems correlated with malorientation of the acetabular component. There were no such mechanical problems in the navigated group.

We conclude that CT-based navigation increased the precision of orientation of the acetabular component and control of limb length in total hip replacement, without navigation-related complications. It also reduced the rate of dislocation and mechanical problems related to impingement.

We studied prospectively the change over ten years in mortality, walking ability and place of residence after a hip fracture in 753 patients in Japan. We compared the deaths observed in these patients with those expected in the general population, matched for age, gender and calender year at the time of fracture. The survival rate decreased dramatically for two years after the event and the mortality risk remained higher for ten years. This risk was approximately double that of the general population, even at ten years after fracture. The risk was higher, and remained so for longer, in younger rather than in older patients.

The proportion of patients who were able to walk outdoors alone, with or without an assistive device, was 68% (514) before fracture. This decreased to 56% (340) by one year after and remained stable at approximately 63% (125) until ten years. The proportion of patients living in their own home was 84% (629) before fracture, 81% (491) one year later, and then remained stable at approximately 86% (171) until ten years after the event.

Metal-on-metal bearings are being increasingly used in young patients. The potential adverse effects of systemic metal ion elevation are the subject of ongoing investigation. The purpose of this study was to investigate whether cobalt and chromium ions cross the placenta of pregnant women with a metal-on-metal hip resurfacing and reach the developing fetus. Whole blood levels were estimated using high-resolution inductively-coupled plasma mass spectrometry.

Our findings showed that cobalt and chromium are able to cross the placenta in the study patients with metal-on-metal hip resurfacings and in control subjects without any metal implants. In the study group the mean concentrations of cobalt and chromium in the maternal blood were 1.39 μg/l (0.55 to 2.55) and 1.28 μg/l (0.52 to 2.39), respectively. The mean umbilical cord blood concentrations of cobalt and chromium were comparatively lower, at 0.839 μg/l (0.42 to 1.75) and 0.378 μg/l (0.14 to 1.03), respectively, and this difference was significant with respect to chromium (p < 0.05).

In the control group, the mean concentrations of cobalt and chromium in the maternal blood were 0.341 μg/l (0.18 to 0.54) and 0.199 μg/l (0.12 to 0.33), and in the umbilical cord blood they were 0.336 μg/l (0.17 to 0.5) and 0.194 μg/l (0.11 to 0.56), respectively. The differences between the maternal and umbilical cord blood levels in the controls were marginal, and not statistically significant (p > 0.05). The mean cord blood level of cobalt in the study patients was significantly greater than that in the control group (p < 0.01). Although the mean umbilical cord blood chromium level was nearly twice as high in the study patients (0.378 μg/l) as in the controls (0.1934 μg/l), this difference was not statistically significant. (p > 0.05)

The transplacental transfer rate was in excess of 95% in the controls for both metals, but only 29% for chromium and 60% for cobalt in study patients, suggesting that the placenta exerts a modulatory effect on the rate of metal ion transfer.

We reviewed the initial post-operative radiographs of the Trident acetabulum and identified a problem with seating of the metal-backed ceramic liner. We identified 117 hips in 113 patients who had undergone primary total hip replacement using the Trident shell with a metal-backed alumina liner. Of these, 19 (16.4%) were noted to have incomplete seating of the liner, as judged by plain anteroposterior and lateral radiographs. One case of complete liner dissociation necessitating early revision was not included in the prevalence figures. One mis-seated liner was revised in the early post-operative period and two that were initially incompletely seated were found on follow-up radiographs to have become correctly seated. There may be technical issues with regard to the implanting of this prosthesis of which surgeons should be aware. However, there is the distinct possibility that the Trident shell deforms upon implantation, thereby preventing complete seating of the liner.