Neck narrowing in resurfacing hip arthroplasty: a vascular insult?

INTRODUCTION

Recent reports show increased failure rates in hip resurfacings that display >10 % neck narrowing. The etiology of neck narrowing remains unknown.

METHODS

We assessed 80 hip resurfacings at mean 3.5 years follow-up.

RESULTS

The overall rate of significant narrowing was 11.25 %. Neck narrowing occurred in 4 % of patients using an anterolateral approach and 23.3 % using a posterior approach (P = 0.019). Logistic regression showed that both surgical approach and cup inclination angle were the most important risk factors for the development of narrowing. The odds of the presence of narrowing increased for every degree increase in cup abduction angle (P = 0.021). There was no significant association with age, sex, pre-operative diagnosis, pre- and post-operative SF-36 scores, neck shaft angle, femoral or acetabular component sizes.

CONCLUSION

We postulate that neck narrowing is a result of damage to the medial circumflex femoral vessel when resurfacing through a posterior approach.