MINIMUM FIVE-YEAR FOLLOW-UP OF BIRMINGHAM HIP RESURFACING ARTHROPLASTY – AN INDEPENDENT SINGLE SURGEON’S EXPERIENCE OF 100 CASES

Abstract

Aim: We present the outcome of Birmingham Hip Resurfacing Arthroplasty performed by a single surgeon after at least five years follow up.

Patients and Methods: One hundred hips in 84 patients were studied with a mean follow-up of 6.4 years (5–8.3 years), performed by a single surgeon. Three patients died of unrelated causes and 2 patients were lost to follow-up, hence the study group comprised of 79 patients with 95 hips. Birmingham resurfacing femoral and acetabular components were used in all patients.

The clinical outcome was measured using Harris, Charnley, Oxford hip scores and quality of life using SF-36. Radiographs were systematically analysed for implant position, fixation, and loosening.

Results: The mean age was 54 years (20–74years) and BMI of 28 (19–35). Primary osteoarthritis was seen in 69 hips. Six patients (6.1%) underwent revision of the femoral component (3 for peri-prosthetic fractures of the neck of femur, 2 for deep infection and 1 for collapse due to AVN). None of the patients had evidence of loosening around the acetabular component and femoral components in 28 patients. Type 1 pedestal sign was seen in 61 hips and Type 2 in 2 hips.

The clinical scores were respectively, Harris 85 (25–100), Oxford 21.5 (12–52), mean Charnley score 4.8 for pain, 5.3 for movement and 4.3 for mobility; the mean SF-36 score were 44 (12–58) for the physical and 51.4 (19–71) for the mental component. With an end point of definite or probable aseptic loosening, the probability of survival at 5 years was 100% and 97.3% (95% CI = 2.9) for acetabular and femoral components respectively. Overall survival at 5years with removal or repeat revision of either component for any reason as the end point was 91% (95% CI: 82 to 97%).

Conclusion: The results of this study support the continued use of Birmingham Hip Resurfacing Arthroplasty in young active individuals. As loosening can occur as a late phenomenon, a longer follow up is needed to determine longevity, durability of this prosthesis.