Hip impingement in slipped capital femoral epiphysis: a changing perspective.

BACKGROUND: Femoroacetabular impingement (FAI) as a result of slipped capital femoral epiphysis (SCFE) has recently gained significant attention. Seen as an intermediate step toward the development of early osteoarthritis, symptomatic FAI develops in SCFE patients who have residual hip deformity characterized by relative posterior and medial displacement of the capital femoral epiphysis, leading to an anterolateral prominence of the metaphysis which abuts on the acetabular rim. This results in a decreased range of hip motion as well as progressive labral damage and articular cartilage injury, which cause symptoms of FAI. All degrees of slips from mild to severe can develop impingement.

METHODS: The existing literature on the subject was thoroughly reviewed and all levels of studies that have made any meaningful changes to clinical practice were considered.

RESULTS: Based on the literature review, current practice trends, and our own institutional practice pattern, all treatment options for SCFE in the impingement era have been presented with an open discussion regarding potential benefits and limitations.

CONCLUSIONS: Several surgical options exist for the SCFE patient who develops FAI. These are largely determined by the degree of deformity present and severity of the initial slip. Extraarticular (intertrochanteric, base of the neck) as well as subcapital osteotomies can be utilized with a goal of restoring proximal femoral anatomy in order to minimize the effect of the anterolateral prominence in more severe deformities. Patients with milder deformities can undergo osteochondroplasty of the femoral head and neck to remove impinging structures via either an open or arthroscopic approach. Also, proximal femoral osteotomy and open head-neck recontouring can be combined. Finally, patients who develop pain very early after in situ pinning must also be examined for potential iatrogenic screw-head impingement as a source of their pain and decreased hip motion, in addition to abnormalities in the proximal femoral anatomy. There are many centers that are approaching acute unstable SCFE patients as well as the more displaced stable cases with open reduction techniques that seem to be demonstrating good mid-term results. The goal of treatment is to improve patient function, alleviate hip pain, and to delay or prevent the development of early degenerative changes in adolescents and young adults. Prospective multi-center studies will be necessary so as to determine what methods work best in treatment and delay the onset and progression of osteoarthritis.

LEVEL OF EVIDENCE: V.