Open reduction and internal fixation of unstable slipped capital femoral epiphysis by means of surgical dislocation does not decrease the rate of avascular necrosis: a preliminary study

Abstract

Purpose: The treatment of unstable slipped capital femoral epiphysis (SCFE) remains controversial. Surgical dislocation and open reduction has the potential to significantly reduce the rate of avascular necrosis (AVN) by allowing direct preservation of the femoral head blood supply. The purpose of this study was to determine if open reduction of the unstable SCFE by means of surgical hip dislocation reduced the risk of AVN compared with closed reduction and percutaneous pinning.

Methods: We reviewed the medical records and radiographs of patients treated at our institution between the years 2000 and 2008. Sex, age, side of slip, precipitating event, pre- and post-operative anterior physeal separation (APS) and slip angle, slip severity, time between inciting event and surgical treatment, number of screws used, development of AVN, and need for subsequent surgery were evaluated. Statistical analysis was performed to compare risk factors and occurrence of AVN.

Results: From 2004 to 2008, we treated 12 patients with unstable SCFEs: six had closed reduction and percutaneous pinning and six underwent open reduction by means of surgical hip dislocation. There were no statistically significant differences between the two groups regarding sex, age, slip angle, APS, time to surgery, and AVN rate. At follow-up, 4 (66.7 %) patients had AVN in the group which had open reduction, while 2 (33.3 %) patients had AVN in the group which underwent closed reduction. (p = 0.57).

Conclusions: Open reduction of the unstable SCFE by means of surgical dislocation of the hip does not decrease the rate of AVN when compared to closed reduction.

Keywords: Avascular necrosis; Closed reduction; Open reduction; Percutaneous pinning; Slipped capital femoral epiphysis; Surgical dislocation of the hip.

Fig. 1

a A 12-year-old girl was diagnosed with right unstable slipped capital femoral epiphysis (SCFE) and left chronic SCFE. b–c The patient underwent right subcapital corrective osteotomy and open reduction through means of surgical dislocation of the hip and left in situ fixation with a 7.3-mm fully threaded screw. d Six weeks after surgery, one of the K-Wires was broken. The patient had no pain. e A bone scan revealed that both femoral heads were perfused and the patient was taken to the operating room for hardware revision, performed percutaneously. The two Kirschner wires were removed and a 7.3-mm screw was put in place. f–g At 13 months of follow-up, there were no signs of avascular necrosis (AVN) and the patient did not have any limitations or hip pain

Fig. 2

a An 11-year-old girl was diagnosed with a left unstable SCFE, after falling on ice. b–c The patient underwent subcapital corrective osteotomy and open reduction through means of surgical dislocation of the hip. d Left hip AVN was noticed at 6 months follow-up. e The hardware was removed and a hinged hip distractor external fixator was applied for 7 months. f At 2 years follow-up, the patient has hip pain and restricted motion. A contralateral distal femoral epiphysiodesis was performed to partially address the limb length discrepancy