In this prospective study a total of 80 consecutive Chinese patients with Crowe type I or II developmental dysplasia of the hip were randomly assigned for hip resurfacing arthroplasty (HRA) or total hip replacement (THR).

Three patients assigned to HRA were converted to THR, and three HRA patients and two THR patients were lost to follow-up. This left a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips) who underwent THR. The mean follow-up was 59.4 months (52 to 70) in the HRA group and 60.6 months (50 to 72) in the THR group. There was no failure of the prosthesis in either group. Flexion of the hip was significantly better after HRA, but there was no difference in the mean post-operative Harris hip scores between the groups. The mean size of the acetabular component in the HRA group was significantly larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was no difference in the mean abduction angle of the acetabular component between the two groups.

Although the patients in this series had risk factors for failure after HRA, such as low body weight, small femoral heads and dysplasia, the clinical results of resurfacing in those with Crowe type I or II hip dysplasia were satisfactory. Patients in the HRA group had a better range of movement, although neck-cup impingement was observed. However, more acetabular bone was sacrificed in HRA patients, and it is unclear whether this will have an adverse effect in the long term.

Objectives

There is increasing application of bone morphogenetic proteins (BMPs) owing to their role in promoting fracture healing and bone fusion. However, an optimal delivery system has yet to be identified. The aims of this study were to synthesise bioactive BMP-2, combine it with a novel α-tricalcium phosphate/poly(D,L-lactide-co-glycolide) (α-TCP/PLGA) nanocomposite and study its release from the composite.

We compared the performance of uncemented trabecular metal tibial components in total knee replacement with that of cemented tibial components in patients younger than 60 years over two years using radiostereophotogrammetric analysis (RSA). A total of 22 consecutive patients (mean age 53 years, 33 to 59, 26 knees) received an uncemented NexGen trabecular metal cruciate-retaining monobloc tibial component and 19 (mean 53 years, 44 to 59, 21 knees) a cemented NexGen Option cruciate-retaining modular tibial component.

All the trabecular metal components migrated during the initial three months and then stabilised. The exception was external rotation, which did not stabilise until 12 months. Unlike conventional metal-backed implants which displayed a tilting migration comprising subsidence and lift-off from the tibial tray, most of the trabecular metal components showed subsidence only, probably due to the elasticity of the implant.

This pattern of subsidence is regarded as being beneficial for uncemented fixation.

Revision arthroplasty of the hip is expensive owing to the increased cost of pre-operative investigations, surgical implants and instrumentation, protracted hospital stay and drugs. We compared the costs of performing this surgery for aseptic loosening, dislocation, deep infection and peri-prosthetic fracture. Clinical, demographic and economic data were obtained for 305 consecutive revision total hip replacements in 286 patients performed at a tertiary referral centre between 1999 and 2008. The mean total costs for revision surgery in aseptic cases (n = 194) were £11 897 (sd 4629), for septic revision (n = 76) £21 937 (sd 10 965), for peri-prosthetic fracture (n = 24) £18 185 (sd 9124), and for dislocation (n = 11) £10 893 (sd 5476). Surgery for deep infection and peri-prosthetic fracture was associated with longer operating times, increased blood loss and an increase in complications compared to revisions for aseptic loosening. Total inpatient stay was also significantly longer on average (p < 0.001). Financial costs vary significantly by indication, which is not reflected in current National Health Service tariffs.

We report the clinical and radiographic outcome of a consecutive series of 138 hydroxyapatite-coated total knee replacements with a mean follow-up of 11 years (10 to 13). The patients were entered into a prospective study and all living patients (76 knees) were evaluated. The Hospital for Special Surgery knee score was obtained for comparison with the pre-operative situation. No patient was lost to follow-up. Radiographic assessment revealed no loosening. Seven prostheses have been revised, giving a cumulative survival rate of 93% at 13 years. We believe this to be the longest follow-up report available for an hydroxyapatite-coated knee replacement and the first for this design of Insall-Burstein II knee.

A 70-year-old man with an uncemented metal-on-polyethylene total hip prosthesis underwent revision arthroplasty 33 months later because of pain, swelling and recurrent dislocation. There appeared to be corrosion and metal release from the prosthetic head, resulting in pseudotumour formation and severe local soft-tissue destruction. The corrosion occurred at the junction between the titanium-molybdenum-zirconium-iron taper and the cobalt-chrome-molybdenum head, but the mechanism was unproven.

Objectives

This study aims to assess the correlation of CT-based structural rigidity analysis with mechanically determined axial rigidity in normal and metabolically diseased rat bone.

The best method of reconstruction after resection of malignant tumours of the tibial diaphysis is unknown. In the absence of any long-term studies analysing the results of intercalary endoprosthetic replacement, we present a retrospective review of 18 patients who underwent limb salvage using a tibial diaphyseal endoprosthetic replacement following excision of a malignant bone tumour. There were ten men and eight women with a mean age of 42.5 years (16 to 76). Mean follow-up was 58.5 months (20 to 141) for all patients and 69.3 months (20 to 141) for the 12 patients still alive. Cumulative patient survival was 59% (95% confidence interval (CI) 32 to 84) at five years. Implant survival was 63% (95% CI 35 to 90) at ten years. Four patients required revision to a proximal tibial replacement at a mean follow-up of 29 months (10 to 54). Complications included metastases in five patients, aseptic loosening in four, peri-prosthetic fracture in two, infection in one and local recurrence in one. The mean Musculoskeletal Tumor Society score and the mean Toronto Extremity Salvage Score were 23 (17 to 28) and 74% (53 to 91), respectively.

Although rates of complication and revision were high, custom-made tibial diaphyseal replacement following resection of malignant bone tumours enables early return to function and provides an attractive alternative to other surgical options, without apparent compromise of patient survival.

The long-term results of grafting with hydroxyapatite granules for acetabular deficiency in revision total hip replacement are not well known. We have evaluated the results of revision using a modular cup with hydroxyapatite grafting for Paprosky type 2 and 3 acetabular defects at a minimum of ten years’ follow-up. We retrospectively reviewed 49 acetabular revisions at a mean of 135 months (120 to 178). There was one type 2B, ten 2C, 28 3A and ten 3B hips. With loosening as the endpoint, the survival rate was 74.2% (95% confidence interval 58.3 to 90.1). Radiologically, four of the type 3A hips (14%) and six of the type 3B hips (60%) showed aseptic loosening with collapse of the hydroxyapatite layer, whereas no loosening occurred in type 2 hips. There was consolidation of the hydroxyapatite layer in 33 hips (66%). Loosening was detected in nine of 29 hips (31%) without cement and in one of 20 hips (5%) with cement (p = 0.03, Fisher’s exact probability test). The linear wear and annual wear rate did not correlate with loosening.

These results suggest that the long-term results of hydroxyapatite grafting with cement for type 2 and 3A hips are encouraging.

Total hip replacement in patients with Gaucher’s disease with symptomatic osteonecrosis of the femoral head is controversial because of the high early failure rates. We describe four patients who had an uncemented total hip replacement following enzyme replacement therapy for a median of two years and one month (1 to 9.8 years) prior to surgery, and who remained on treatment. At operation, the bone had a normal appearance and consistency. Histopathological examination showed that, compared with previous biopsies of untreated Gaucher’s disease, the Gaucher cell infiltrate had decreased progressively with therapy, being replaced by normal adipose tissue. The surfaces of viable bone beyond the osteonecrotic areas showed osteoblasts, indicating remodelling. In one case acetabular revision was carried out after 11 years and eight months. The three remaining patients had a mean follow-up of six years and four months (3.3 to 12 years). We recommend initiating enzyme replacement therapy at least one to two years prior to total hip replacement to facilitate bone remodelling and to allow implantation of uncemented components in these young patients.

The outcome of total hip replacement (THR) is potentially affected by the body mass index (BMI) of the patient. We studied the outcome of 2026 consecutive primary cementless THRs performed for osteoarthritis. The mean follow-up was 6.3 years (0 to 11.71) and no patient was lost to follow-up for survival analysis. The patients were divided into two groups according to their BMI as follows: non-obese (BMI < 30 kg/m²) and obese (BMI ≥ 30 kg/m²).

The obese patient undergoing surgery was found to be significantly younger (p < 0.001). The log-rank test for equality of survival showed no difference in the mid-term survival (p = 0.552) with an estimated survival at 11 years of 95.2% (95% CI 92.5 to 98.0) in the non-obese and 96.7% (95% CI 94.9 to 98.5) in the obese groups. The clinical and radiological outcome was determined in a case-matched study performed on 134 obese individuals closely matched with 134 non-obese controls. The non-obese group was found to have a significantly higher post-operative Harris hip score (p < 0.001) and an increased range of movement, but overall satisfaction with surgery was comparable with that of the obese patients. Radiological analysis of the acetabular and femoral components showed no significant differences with regard to radiolucent lines, osteolysis, ingrowth of the femoral component, the acetabular inclination angle or alignment of the femoral component. Our results suggest that the survival of cementless THR is not adversely affected by obesity. Obese patients can therefore be counselled that despite a lower clinical score, they should expect to be satisfied with the result of their THR with a mid-term survival rate equivalent to that of non-obese patients.

Hydroxyapatite-coated standard anatomical and customised femoral stems are designed to transmit load to the metaphyseal part of the proximal femur in order to avoid stress shielding and to reduce resorption of bone. In a randomised in vitro study, we compared the changes in the pattern of cortical strain after the insertion of hydroxyapatite-coated standard anatomical and customised stems in 12 pairs of human cadaver femora. A hip simulator reproduced the physiological loads on the proximal femur in single-leg stance and stair-climbing. The cortical strains were measured before and after the insertion of the stems.

Significantly higher strain shielding was seen in Gruen zones 7, 6, 5, 3 and 2 after the insertion of the anatomical stem compared with the customised stem. For the anatomical stem, the hoop strains on the femur also indicated that the load was transferred to the cortical bone at the lower metaphyseal or upper diaphyseal part of the proximal femur.

The customised stem induced a strain pattern more similar to that of the intact femur than the standard, anatomical stem.

Second-generation metal-on-metal bearings were introduced as a response to the considerable incidence of wear-induced failures associated with conventional replacements, especially in young patients. We present the results at ten years of a consecutive series of patients treated using a metal-on-metal hip resurfacing. A distinct feature of the bearings used in our series was that they had been subjected to double-heat treatments during the post-casting phase of their manufacture. In the past these bearings had not been subjected to thermal treatments, making this a unique metal-on-metal bearing which had not been used before in clinical practice.

We report the outcome of 184 consecutive hips (160 patients) treated using a hybrid-fixed metal-on-metal hip resurfacing during 1996. Patients were invited for a clinicoradiological follow-up at a minimum of ten years. The Oxford hip score and anteroposterior and lateral radiographs were obtained. The mean age at operation was 54 years (21 to 75). A series of 107 consecutive hips (99 patients) who received the same prosthesis, but subjected to a single thermal treatment after being cast, between March 1994 and December 1995, were used as a control group for comparison.

In the 1994 to 1995 group seven patients (seven hips) died from unrelated causes and there were four revisions (4%) for osteolysis and aseptic loosening. In the 1996 group nine patients died at a mean of 6.9 years after operation because of unrelated causes. There were 30 revisions (16%) at a mean of 7.3 years (1.2 to 10.9), one for infection at 1.2 years and 29 for osteolysis and aseptic loosening. Furthermore, in the latter group there were radiological signs of failure in 27 (24%) of the 111 surviving hips.

The magnitude of the problem of osteolysis and aseptic loosening in the 1996 cohort did not become obvious until five years after the operation. Our results indicate that double-heat treatments of metal-on-metal bearings can lead to an increased incidence of wear-induced osteolysis.

Successful healing of a nine-year tibial nonunion resistant to six previous surgical procedures was achieved by tissue engineering. We used autologous bone marrow stromal cells (BMSCs) expanded to 5 × 10⁶ cells after three weeks’ tissue culture. Calcium sulphate (CaSO₄) in pellet form was combined with these cells at operation. The nonunion was clinically and radiologically healed two months after implantation.

This is the description of on healing of a long-standing tibial nonunion by tissue engineering. The successful combination of BMSCs and CaSO₄ has not to our knowledge been reported in a clinical setting.

We describe the results of Copeland surface replacement shoulder arthroplasty using the mark III prosthesis in patients over 80 years of age. End-stage arthritis of the shoulder is a source of significant pain and debilitating functional loss in the elderly. An arthroplasty offers good relief of pain and may allow the patient to maintain independence. The risk-benefit ratio of shoulder replacement may be felt to be too high in an elderly age group, but there is no published evidence to support this theory. We have assessed whether the procedure was as reliable and safe as previously seen in a younger cohort of patients. Between 1993 and 2003, 213 Copeland surface replacement arthroplasty procedures were performed in our unit, of which 29 (13.6%) were undertaken in patients over the age of 80. This group of patients was followed up for a mean of 4.5 years (2.1 to 9.3). Their mean age was 84.3 years (81 to 93), the mean operating time was 40 minutes (30 to 45) and the mean in-patient stay was five days (2 to 21). There were no peri-operative deaths or significant complications. The mean Constant score adjusted for age and gender, improved from 15.1% to 77%. Copeland surface replacement shoulder arthroplasty may be performed with minimal morbidity and rapid rehabilitation in the elderly.

Between 1976 and 2004, 38 revision arthroplasties (35 patients) were performed for aseptic loosening of the humeral component. The mean interval from primary arthroplasty to revision was 7.1 years (0.4 to 16.6). A total of 35 shoulders (32 patients) were available for review at a mean follow-up of seven years (2 to 19.3).

Pre-operatively, 34 patients (97%) had moderate or severe pain; at final follow-up, 29 (83%) had no or only mild pain (p < 0.0001). The mean active abduction improved from 88° to 107° (p < 0.01); and the mean external rotation from 37° to 46° (p = 0.27). Excellent or satisfactory results were achieved in 25 patients (71%) according to the modified Neer rating system. Humeral components were cemented in 29, with ingrowth implants used in nine cases. There were 19 of standard length and 17 were longer (two were custom replacements and are not included). Bone grafting was required for defects in 11 humeri. Only two glenoid components were left unrevised. Intra-operative complications included cement extrusion in eight cases, fracture of the shaft of the humerus is two and of the tuberosity in four. There were four re-operations, one for recurrent humeral loosening, with 89% survival free of re-operations at ten years.

Revision surgery for aseptic loosening of the humeral component provides reliable pain relief and modest improvement of movement, although there is a substantial risk of intra-operative complications. Revision to a total shoulder replacement gives better results than to a hemiarthroplasty.

We identified ten patients who underwent arthroscopic revision of anterior shoulder stabilisation between 1999 and 2005. Their results were compared with 15 patients, matched for age and gender, who had a primary arthroscopic stabilisation during the same period.

At a mean follow-up of 37 and 36 months, respectively, the scores for pain and shoulder function improved significantly between the pre-operative and follow-up visits in both groups (p = 0.002), with no significant difference between them (p = 0.4). The UCLA and Rowe shoulder scores improved significantly (p = 0.004 and p = 0.002, respectively), with no statistically significant differences between groups (p = 0.6). Kaplan-Meier analysis for time to recurrent instability showed no differences between the groups (p = 0.2).

These results suggest that arthroscopic revision anterior shoulder stabilisation is as reliable as primary arthroscopic stabilisation for patients who have had previous open surgery for recurrent anterior instability.

The dysplasia cup, which was devised as an adjunct to the Birmingham Hip Resurfacing system, has a hydroxyapatite-coated porous surface and two supplementary neutralisation screws to provide stable primary fixation, permit early weight-bearing, and allow incorporation of morcellised autograft without the need for structural bone grafting.

A total of 110 consecutive dysplasia resurfacing arthroplasties in 103 patients (55 men and 48 women) performed between 1997 and 2000 was reviewed with a minimum follow-up of six years. The mean age at operation was 47.2 years (21 to 62) and 104 hips (94%) were Crowe grade II or III.

During the mean follow-up of 7.8 years (6 to 9.6), three hips (2.7%) were converted to a total hip replacement at a mean of 3.9 years (2 months to 8.1 years), giving a cumulative survival of 95.2% at nine years (95% confidence interval 89 to 100). The revisions were due to a fracture of the femoral neck, a collapse of the femoral head and a deep infection. There was no aseptic loosening or osteolysis of the acetabular component associated with either of the revisions performed for failure of the femoral component. No patient is awaiting a revision.

The median Oxford hip score in 98 patients with surviving hips at the final review was 13 and the 10th and the 90th percentiles were 12 and 23, respectively.