Subsidence in Collarless Corail Hip Replacement.

The purpose of this study was to assess whether subsidence occurs in collarless Corail hip replacement (CCHR) and to ascertain the extent and timing of subsidence if present. Retrospective case notes analysis was performed. Sixty eight patients who had CCHR were identified from our database. Male to female ratio was 32:36. Their mean age was 74.2 years (range 37-95 years). Indications for surgery were osteoarthritis in 64 (94%) patients, rheumatoid arthritis in two (3%) patients and avascular necrosis in two (3%) patients. Subsidence was measured at 6 weeks, 6 months and 1 year post-op compared to initial post-op x-rays. At 6 weeks x-ray 21 patients did not have any subsidence, 18 patients had 1 millimeter (mm) subsidence, 10 patients had 2mms subsidence, 4 patients had 3mms subsidence, 5 patients had 4mms subsidence, 1 patient had 5mms subsidence, 4 patients had 6 mms subsidence and 1 patient each had subsidence of 7mms, 9mms, 11mms, 13mms and 26 mms respectively. When compared with 6 months x-rays only 2 patients had a further subsidence of 2mms while another patient had 3mms subsidence. No further subsidence occurred at 1 year follow up x-rays. One patient had revision surgery due to symptomatic subsidence (29mms) at 6 months follow up. Subsidence does occur in the first 6 weeks in collarless Corail hip replacement, and to a lesser extent until 6 months postoperatively, but does not progress further.