Slipped upper femoral epiphysis: Outcome after in situ fixation and capital realignment technique

Abstract

Background: Slipped upper femoral epiphysis (SUFE) is the gradually acquired malalignment of the upper femoral epiphysis (capital) and the proximal femoral metaphysis. SUFE is uncommon in India, and there are no previous studies on outcome and clinical characteristics of patients with SUFE from India. This study evaluates the presentation, disease associations and outcome of SUFE from a tertiary care centre in India.

Materials and methods: Twenty six consecutive children with SUFE seen over a period of 4 years were reviewed. The clinical presentations, severity of the slip, surgical interventions (n=30) were assessed. Twenty one boys and five girls with a mean age 13.1 years (range 10-16 years) were included in the study. Four children had bilateral involvement. There were 4 rural and 22 urban children from the eastern and southern states of the country. The presentation was acute in 7, acute on chronic in 5, and chronic in 14, with a mean duration of symptoms of 51 days (range 3-120 days). Slips were stable in 16 and unstable in 10 children. Two children had adiposogenital syndrome. Body mass index was high in 12 out of 23 children. Vitamin D levels were low in 20 out of 21 children, with a mean vitamin D level of 12.61 ± 5 ng/ml. Eighteen children underwent in situ pinning. Eight children underwent capital realignment.

Results: Clinical outcome as assessed by Merle d' Aubigne score was excellent in 6, good in 10, fair in 6 and poor in 1. Half of the in situ fixation patients underwent osteoplasty procedure for femoroacetabular impingement and 5 more were symptomatic. The head neck offset and α angle after in situ pinning were -1.12 ± 3 mm and 66.05 ± 9.7°, respectively and this improved to 8.7 mm and 49°, respectively, after osteoplasty. One child in the pinning group had chondrolysis. Eight patients with severe slip underwent capital realignment. Mean followup was 20.15 months. The anterior head neck offset and α angle were corrected to 6.8 ± 1.72 mm and 44.6 ± 7.0° mm, respectively. Two children with unstable slip in the capital realignment group had avascular necrosis which was diagnosed at presentation by bone scan.

Conclusion: High BMI, vitamin D deficiency and endocrine disorders are associated with SUFE in India and should be evaluated as some of these are amenable to prevention and treatment. Most patients treated with in situ pinning developed femoroacetabular impingement. The early results after capital realignment procedure are encouraging and help to avoid a second procedure which is needed in a majority of patients who underwent in situ pinning.

Keywords: Capital realignment; femoroacetabular impingement; modified dunn procedure; slipped upper femoral epiphysis.

Figure 1

X-ray pelvis with both hip joints (a) Anteroposterior view of a 15-year-old boy showing a mild slip. The blurring of physis (Blanch sign) and capital epiphysis dipping below the Klein's line are observed. (b) Frog leg lateral view of the same child showing slip angle (Southwick) measuring 20° on the right side. (c and d) AP and frog leg lateral views showing a centrally placed cannulated screw crossing the physis

Figure 2

X-ray pelvis with both hip joints (a and b) A 12-year-old showing severe slip (Southwick 75°) on the left side. (c and d) AP and frog leg lateral radiographs 2 months after capital realignment through Ganz safe surgical dislocation approach for the hip

Figure 3

X-ray pelvis with both hip joints (a and b) A 13-year-old boy presented with chronic (duration 120 days), stable and severe slip 80° on the right side. (c) Two-year post operative in situ pinning with clinical impingement showing femoroacetabular impingement. (d) Postoperative radiographs of in situ pinning and osteoplasty

Figure 4

X-ray pelvis showing both hips (a) and left hip frog leg view (b) in a 14-year-old boy presented with acute, unstable, and severe slip measuring 72° (Southwick angle) and initially treated with a single cannulated screw. The patient was symptomatic for impingement, southwick° angle was 75° and head neck offset was negative, i.e. neck with larger radius than head. (c and d) Six weeks after osteoplasty through Ganz approach combined with subtrochanteric osteotomy to correct varus, rotation, and extension deformity

Figure 5

(a) Fluoroscopic anteroposterior view in a 14-year-old boy managed for chronic, severe slip on the left side with in situ pinning intraoperative image showing six threads crossing physis. (b) postoperative anteroposterior radiograph at nine months showing reduction in the joint space

Figure 6

X-ray pelvis showing both hips anteroposterior view (a) and right hip frog leg lateral view (b) in a 14-year-old boy showing unstable, severe slip of 2 months duration. There is an increased density of the capital femoral epiphysis and Southwick slip angle of 80° (c) Bone scan at presentation before surgery showing decreased uptake in the femoral head. (d and e) Radiographs taken at 1 year post capital realignment through Ganz approach showing fused physis, increased density of the femoral head due to avascular necrosis

Figure 7

Associated risk factors in SUFE