Introduction

We aim to report the clinical and radiological outcome of consecutive primary hip arthroplasties using the JRI-Furlong HAC coated femoral and acetabular components.

Aims: Minimum ten year clinical, radiological and postmortem results of the flexible Cambridge Cup. This acetabular prosthesis was designed to replace the horseshoe shaped articular cartilage and provide physiological loading with minimal resection of healthy bone.

Method: Fifty female patients aged over 70 years with a displaced intra-capsular fracture of the femoral neck were recruited to the ethically-approved prospective study. They underwent implantation of the Cambridge Cup, which has an outer polybutyleneterephthalate shell and an inner UHMWPE bearing, with a Thompson-type hemiarthroplasty. The cups were manufactured with a 60μm plasma-sprayed coating of hydroxyapatite. This was removed from half the cups to simulate the effects of long-term HA resorption. Implants were sterilised by gamma irradiation in air. Independent clinical and radiological assessments were undertaken before discharge, at 6 weeks, one year, 18 months, two -, five-, seven- and ten years. Patients were scored using the Barthel Index, the Charnley-modified Merle d’Aubigne scores and latterly the Oxford hip score. The date and cause of death were obtained from hospital records and death certificates. Fifteen Cambridge Cups were retrieved post-mortem for histological and wear analysis

Results: The mean functional scores recovered to levels before fracture. These scores decreased with advancing age at five years. The mortality rates were 16%, 28%, 46% and 92% at 1, 2, 5 and 10 years. The Oxford hip scores in patients surviving between five and ten years were maintained.

The HA coated implants remained asymptomatic. Three uncoated components required revision for migration. No evidence of accelerated UHMWPE wear was seen on retrievals or radiographs. Histological analysis of the retrieved HA coated specimens showed excellent bony fixation, uncoated cups showed predominantly fibrous tissue.

Conclusion: The uncemented Cambridge Cup was implanted in a challenging environment of osteoporotic bone. Clinical, radiographic and post-mortem results up to ten years are excellent.

We aim to report the clinical, radiological outcome of consecutive primary hip arthroplasties using the JRI-Furlong Hydroxyapatite ceramic coated acetabular components. We reviewed 412 consecutive primary THA using fully coated acetabular shell in 392 patients, with minimum 12-year follow-up to 18 years, performed at two institutions. Twenty (22 THA) were lost prior to 12-year follow-up, leaving 372 patients (390 THA) available for study.

Fully HAC coated stems were used in all patients. Clinical outcome was measured using Harris, Charnley Oxford, EuroQol EQ-5D scores. Radiographs were systematically analysed for implant position, loosening, migration, osteolysis. Polythene wear was digitally measured.

Mean age was 74.4 yrs. Dislocation occurred in 10 patients (3 recurrent). Revision operations were performed in nine patients (1.9%). Four acetabular revisions were performed for aseptic loosening. Other re-operations were for infection (3), periprosthetic fractures (1), cup malposition (1), revision of worn liner (3). The mean Harris and Oxford scores were 87 (78–97) and 19.1 (12–33) respectively. The Charnley score was 5.6 (5–6) for pain, 5.2 (4–6) for movement and 5.3 (4–6) for mobility. Migration of acetabular component was seen in 4 hips. Acetabular radiolucencies were present in 54 hips (9.7%). The mean linear polythene wear was 0.06mm/year. Mean inclination was 48.4 deg(38–65). Mean EQ-5D description scores and health thermometer scores were 0.81 (0.71–0.89) and 86 (64–95). With an end point of definite or probable loosening, the probability of survival at 12 years was 96.1%. Overall survival at 12 years with removal or repeat revision of either component for any reason as the end point was 94.2%.

The results of this study support the continued use of a fully coated prosthesis and documents the durability of the HAC coated components. In our clinical experience, the Furlong prosthesis revealed encouraging radiographic stability over a long term period

Aim: To report the clinical and radiological outcome of consecutive primary hip arthroplasties using the JRI-Furlong Hydroxyapatite ceramic (HAC) coated femoral and acetabular components

Methods: We reviewed 586 consecutive cementless primary THA using HAC coated components in 542 patients, with a minimum 12-year follow-up to 18 years, performed at one institution between 1986 and 1994. Twenty eight (32 THA) were lost prior to 12-year follow-up, leaving 514 patients (554 THA) available for study. Threaded cups were used in 64% and press-fit cups with screws in the rest. Fully HAC coated stems were used in all patients. The clinical outcome was measured using Harris, Charnley and Oxford hip scores. Anterior thigh pain was quantified on a visual analogue scale (VAS) and quality of life using EuroQol EQ-5D. Radiographs were systematically analysed for implant position, loosening, migration, osteolysis and stress shielding. Polythene wear was digitally measured. The radiographic stability of the femoral component was determined by Enghs criteria

Results: The mean age was 75.2 yrs. Dislocation occurred in 12 patients (3 recurrent). Re operations were performed in 11 patients (1.9%). Four acetabular and one stem revisions were performed for aseptic loosening. Other re-operations were for infection (2), periprosthetic fractures (2), cup malposition (1), revision of worn liner (2). The mean Harris and Oxford scores were 89 (79–96) and 18.4 (12–32) respectively. The Charnley score was 5.7 (5–6) for pain, 5.3 (4–6) for movement and 5.4 (4–6) for mobility. Migration of acetabular component was seen in 4 hips. Acetabular radiolucencies were present in 54 hips (9.7%). The mean linear polythene wear was 0.06mm/year. Stable stem by bony ingrowth was identified in all hips excluding one femoral revision case. Mean stem subsidence was 2.2mm (0.30–3.4mm). Radiolucencies were present around 37 (6.6%) stems. Mean EQ- 5D description scores and health thermometer scores were 0.81 (0.71–0.89) and 86 (64–95). With an end point of definite or probable loosening, the probability of survival at 12 years was 96.1% for acetabular and 98.3% for femoral components. Overall survival at 12 years with removal or repeat revision of either component for any reason as the end point was 97.2%.

Conclusion: The results of this study support the continued use of a fully coated prosthesis and documents the durability of the HAC coated components. In our clinical experience, the Furlong prosthesis revealed encouraging radiographic stability over a long term period.

Introduction: Total hip replacements (THR) with the first generation metal-on-metal articulation were abandoned in 1970s in favour of metal-on-polyethylene articulation. Osteolysis due to polyethylene wear particles renewed the interest in metal-on-metal articulations. The second generation had improved clearance, metal hardness and reproducible surfaces. We describe the 10-year outcome of 63 THR with Metasul metal-on-metal articulation.

Methods: From 1995 to 1996, 86 patients (90 hips) underwent THR with Metasul articulation and cemented CF-30 femoral stem. Of these, 55 hips had a cemented Stuhmer-Weber-Allopro cup and 35 hips had an uncemented Allofit cup. Eleven patients (12 hips) died and five patients (6 hips) were not available for clinical evaluation. However all had been contacted and it was known that the hip was not painful and had not been revised. Nine patients were lost to follow up. Thirty nine hips in cemented group and 24 hips in uncemented group had clinical, radiological and Oxford hip score (OHS) at minimum of 10-years follow-up after the operation.

Results: The minimum length of follow up was 10-years with an average of 10.8 years. The average OHS at 10 years for the cemented group was 23 (range 12 – 42) and for the hybrid group was 20.3 (range 12 – 37). Five out of 63 (8%) hips had revision surgery. Two revisions (3%) were performed because of infection, 1 was revised (1.5%) because of unexplained pain and suspected metallosis and 2 were revised (3%) for suspected aseptic acetabular cup loosening.

Conclusion: In comparison with the outcome of first generation metal-on-metal bearing, the hips in our study had lower rate of revision due to acetabular wear and loosening. This is the first study to show that the Metasul articulation has good outcome over a 10-year period. The survivorship is 97% with aseptic loosening as the endpoint for revision surgery.

Computer navigation assistance in total knee arthroplasty (TKA) results in more consistently accurate postoperative alignment of the knee prostheses. However the medium and long term clinical outcomes of computer-navigated TKA are not widely published. Our aim was to compare patient perceived outcomes between computer navigation assisted and conventional TKA using the Oxford knee score (OKS).

We retrospectively collected data on 441 primary TKA carried out by a single surgeon in a dedicated arthroplasty centre over a period of four years. These were divided according to use of computer navigation (group A) or standard instrumentation (group B). There were no statistical differences in baseline Oxford knee score (OKS) and demographic data between the groups. 238 of these had at least a one-year follow-up with 109 in group A and 129 in group B. Two year follow-up data was available for 105 knees with 48 in group A and 57 in group B and a three year follow-up for 45 with 21 and 24 in groups A and B respectively. 12 patients had completed four year follow-up with seven and five knees in groups A and B respectively.

The mean OKS at 1-year follow up was 24.98 (range 12– 54, SD 9.34) for group A and 26.54 (range 12– 51, SD 10.18) for group B (p = 0.25). Similarly at 2-years the mean OKS was 25.40 (range 12– 53, SD 9.51) for group A and 25.56 (range 12– 46, SD 9.67) for group B (p = 0.94). The results were similar for three and four-year follow ups with p values not significant. This study thus revealed that computer assisted TKA does not appear to result in better patient satisfaction when compared to standard instrumentation at midterm follow up.

It is known from long term analysis of conventional TKA that mal-aligned implants have significantly higher failure rates beyond eight to ten years. As use of computer navigation assistance results in a less number of mal-aligned knee prostheses, we believe that these knees will have improved survivorship. The differences in OKS between the two groups should therefore be evident after eight to ten years.