The link between femoroacetabular impingement and subsequent osteoarthritis of the hip has been much debated in recent years. Many views have been put forward holding that FAI morphology increases the risk of developing osteoarthritis in the long term. It has, however, been widely observed that a similar morphology is also present in asymptomatic patients, and in older patients, who ultimately did not develop osteoarthritis. In general, the literature does not provide sufficient information on the link between these two conditions.
Further light has been shed on this question by a new study in which 51 patients were investigated radiologically (anteroposterior and lateral hip radiographs) and followed over 25 years. The alpha angle, the femoral torsion, the lateral centre-edge angle, the crossover sign, the posterior wall sign and the prominence of the ischial spine sign were measured on the anteroposterior radiographs. The degree of osteoarthritis was assessed on the follow-up radiographs, and the hip outcome scores were also assessed.
The mean age of the patients was 43 years. Cam-type morphology showed an increased risk of developing osteoarthritis, and in particular alpha angles ≥ 55° on the anteroposterior and lateral radiographs. Femoral torsion and acetabular version were not risk factors for osteoarthritis.
This study showed that cam-type femoroacetabular impingement in young patients may increase the risk of developing hip osteoarthritis by 5 to 10% in the long term, over a 25-year follow-up.
Source: “Archives of Orthopaedic and Trauma Surgery”, June 2020