Subsidence of the femoral component related to long-term outcome of hip replacement.

We compared the clinical outcome with femoral subsidence and radiographic changes in 102 patients at 9 to 13 years after low friction arthroplasty. In 92 cases with a satisfactory outcome there was an average of 2.3 radiological signs and mean subsidence of less than 5 mm. An unsatisfactory outcome was associated with 3.4 signs per film and with subsidence of more than 5 mm. The radiological signs we describe are often the hallmark of successful load transmission, but if they increase with time or are associated with subsidence of over 5 mm, then clinical failure is likely. Fracture of the cement tip is associated with increased subsidence and adversely affects the long-term clinical outcome.