Protrusio acetabuli: a specific pincer hip disease

The pincer effect is an infrequent subtype of femoroacetabular impingement (FAI). In our experience, cam deformities are more common, easier to treat and have more consistent post-operative outcomes than the pincer FAI subtype. In pincer morphologies, over-coverage of the femoral head may occur in a critical area, limiting range of motion and leading to joint damage. Protrusio acetabuli is perhaps the most severe pincer form with global involvement. In these cases, surgical dislocation with acetabular rim trimming is preferred to the arthroscopic technique (1).