Cam deformity and hip degeneration are common after fixation of a slipped capital femoral epiphysis

Abstract

Background and purpose —Slipped capital femoral epiphysis is thought to result in cam deformity and femoroacetabular impingement. We examined: (1) cam-type deformity, (2) labral degeneration, chondrolabral damage, and osteoarthritic development, and (3) the clinical and patient-reported outcome after fixation of slipped capital femoral epiphysis (SCFE).Methods —We identified 28 patients who were treated with fixation of SCFE from 1991 to 1998. 17 patients with 24 affected hips were willing to participate and were evaluated 10–17 years postoperatively. Median age at surgery was 12 (10–14) years. Clinical examination, WOMAC, SF-36 measuring physical and mental function, a structured interview, radiography, and MRI examination were conducted at follow-up.Results —Median preoperative Southwick angle was 22o (IQR: 12–27). Follow-up radiographs showed cam deformity in 14 of the 24 affected hips and a Tönnis grade > 1 in 1 affected hip. MRI showed pathological alpha angles in 15 affected hips, labral degeneration in 13, and chondrolabral damage in 4. Median SF-36 physical score was 54 (IQR: 49–56) and median mental score was 56 (IQR: 54–58). These scores were comparable to those of a Danish population-based cohort of similar age and sex distribution.Median WOMAC score was 100 (IQR: 84–100).Interpretation —In 17 patients (24 affected hips), we found signs of cam deformity in 18 hips and early stages of joint degeneration in 10 hips. Our observations support the emerging consensus that SCFE is a precursor of cam deformity, FAI, and joint degeneration. Neither clinical examination nor SF-36 or WOMAC scores indicated physical compromise.

Persisting CAM deformity is associated with early cartilage degeneration after Slipped Capital Femoral Epiphysis: 11-year follow-up including dGEMRIC

“…In addition, if a smooth fixation device (such as the Hansson hookpin) is used, the proximal femur will continue to grow in average 7 mm after in situ fixation 6 It was recently shown that the amount of remaining growth of the proximal femur correlates inversely to the reduction of the alpha-angle 31 In other words, the remaining growth will lead to decreased risk of persisting FAI in adulthood. Such remodeling may explain why our patients have relative low alpha angles compared to other studies 25,32,33 . The mean alpha angle in our cohort was 61.5 .…”

“…Previous studies of early cartilage degeneration in the short and mid-term after SCFE are rare. Klit et al 32 and Miese et al investigated 24 respectively 35 SCFE hips 15 and 12 years after slippage and could both verify significantly higher prevalence of chondrolabral damage on structural MRI in hips with pathological alpha angles. Zilkens et al investigated a mix of 28 acute and chronic SCFE hips, at mean age 24 years (range 18e30) using dGEMRIC (1.5 T, 3D sequence).…”

“…In this regard, earlier observations of SCFE patients diverge. Klit et al 32 demonstrated normal ROM while Miese et al 38 showed a significant correlation between increased alpha angle and impaired internal rotation. This inconsistency may reflect the difficulty to measure hip range of motion adequately.…”

The Natural History of Femoroacetabular Impingement

“…Additionally, pediatric hip disorders can predispose to FAI. SCFE deformities have been shown to predispose to the development of cam impingement in adulthood, which is mechanically consistent with the anterosuperior displacement of the femoral metaphysis in the pediatric disease ( 5 , 19 , 22 , 23 ). Similarly, the natural history of LCPD can lead to FAI, in this case resulting from aspherical enlargement of the femoral head (coxa magna) representing the healed osteonecrotic epiphysis ( 23 – 25 ).…”

Slipped Capital Femoral Epiphysis: Long-Term Outcome and Remodelling after in Situ Fixation

“…Nötzli et al describe a mean angle alpha of 74° in a group of patients with symptomatic hip impingement and a mean angle alpha of 42° in a control group of healthy volunteers (7). Klit et al report a mean angle alpha of 83° in a group of SCFE patients 15 years after screw fixation (25). In our study population the mean angle alpha of the affected hips at most recent follow up was 62°, the contralateral hips were 45°.…”