Subcapital correction osteotomy for malunited slipped capital femoral epiphysis

Abstract

Background: Slipped capital femoral epiphysis (SCFE), causing posterior and inferior displacement and retroversion of the femoral head, is a well-recognized etiology for femoroacetabular impingement and can lead to premature arthritis in the young adult. The treatment of malunited SCFE remains controversial. Surgical dislocation and subcapital correction osteotomy (SCO) has been described as a powerful method to correct the proximal femoral deformity.

Methods: Between January 2003 and January 2010, 11 patients (12 hips) with closed femoral physes and symptomatic femoroacetabular impingement from malunited SCFE were treated with surgical dislocation and SCO. We performed a retrospective review of patient histories, physical examinations, operative findings, and preoperative and postoperative anteroposterior (AP) and groin-lateral (GLat) radiographs. Mean follow-up was 61 months.

Results: There were 4 female and 7 male patients with an average age of 15 years at the time of SCO. On the AP radiograph, the mean inferior femoral head displacement (AP epiphyseal-neck angle) was significantly improved (-26 to -6 degrees, P<0.001). On the GLat radiograph, the mean posterior femoral head displacement (lateral epiphyseal-neck angle) was significantly improved (-45 to -3 degrees, P<0.001). The mean α-angle was also significantly improved on both views (AP: 85 to 56 degrees, P<0.001; GLat: 85 to 46 degrees, P<0.001). Operative findings included 1 femoral osteochondral defect, 8 Outerbridge grade 3 to 4 acetabular cartilage lesions, and 10 labral lesions. Significant improvement of the mean Harris Hip Score was seen at latest follow-up (54 to 77, P=0.016). Complications occurred in 4 of the 12 cases with avascular necrosis in 2 patients, a worse postoperative Harris Hip Score in 1 patient, and failure of fixation treated successfully with revision open reduction internal fixation in 1 patient.

Conclusions: SCO as an adjunct to surgical dislocation and osteochondroplasty can be used to correct the deformity of the proximal femur associated with malunited SCFE. Normalization of proximal femoral anatomy may postpone progression to severe osteoarthritis and thus delay the need for arthroplasty in this young patient population. However, surgeons and patients should be aware that the risks of this procedure in this population are significant.

Level of evidence: Level IV-therapeutic study.

Figure 1

Photograph demonstrating preoperative external rotation contracture of the left hip prior to subcapital corrective osteotomy. After surgery the patient was able to internally rotate past neutral both in hip extension and flexion.

Figure 2

Pre and postoperative anteroposterior and groin lateral radiographs demonstrating improved position of the femoral head on the neck with corresponding improved head/neck offset and neck-epiphyseal angle.

Figure 3

Preoperative anteroposterior radiograph demonstrating a skeletally mature hip with a pistol grip deformity consistent with a history of SCFE. Technique for measuring center-trochanteric distance (CTD) and center-trochanteric offset (CTO) are labeled.

Figure 4

Preoperative groin lateral radiograph demonstrating a hip with a SCFE deformity with posterior displacement and retroversion of the femoral head. Technique for measuring the neck-epiphyseal angle (NEA) is demonstrated.

Figure 5

Intraoperative photographs of subcapital correction osteotomy of the femur. Fig. 5a. Intraoperative photograph demonstrating SCFE deformity prior to osteotomy. Fig. 5b. Intraoperative photograph demonstrating elevation and preservation of the vascular pedicle to the femoral head after osteotomy of the subcapital femoral neck. Fig. 5c. Intraoperative photograph demonstrating the femoral head reduced to an anatomic position on the neck prior to preliminary k-wires fixation. Remodeled callus, distal neck, and/or a wafer of posterior trochanter is removed when the vascular pedicle is stretched or impinged.

Figure 5

Intraoperative photographs of subcapital correction osteotomy of the femur. Fig. 5a. Intraoperative photograph demonstrating SCFE deformity prior to osteotomy. Fig. 5b. Intraoperative photograph demonstrating elevation and preservation of the vascular pedicle to the femoral head after osteotomy of the subcapital femoral neck. Fig. 5c. Intraoperative photograph demonstrating the femoral head reduced to an anatomic position on the neck prior to preliminary k-wires fixation. Remodeled callus, distal neck, and/or a wafer of posterior trochanter is removed when the vascular pedicle is stretched or impinged.

Figure 5

Intraoperative photographs of subcapital correction osteotomy of the femur. Fig. 5a. Intraoperative photograph demonstrating SCFE deformity prior to osteotomy. Fig. 5b. Intraoperative photograph demonstrating elevation and preservation of the vascular pedicle to the femoral head after osteotomy of the subcapital femoral neck. Fig. 5c. Intraoperative photograph demonstrating the femoral head reduced to an anatomic position on the neck prior to preliminary k-wires fixation. Remodeled callus, distal neck, and/or a wafer of posterior trochanter is removed when the vascular pedicle is stretched or impinged.

Figure 6

Postoperative anteroposterior pelvis radiograph of one of the two hips that went on to avascular necrosis and subsequent total hip arthroplasty within one year of the subcapital correction osteotomy.