We retrospectively reviewed case records, radiographs, and pre- and posttreatment questionnaires of all 81 patients (84 hips) treated with the surgical dislocation technique for various causes (cam and pincer types of femoroacetabular impingement, Perthes disease, slipped capital femoral epiphysis or SCFE, osteonecrosis, synovial chondromatosis, exostosis, and acetabular fracture reduction) from August 2001 to January 2005. Through this surgical approach, osteoplasty, intertrochanteric osteotomy, or femoral neck osteotomy were performed alone or in combination. For this analysis we excluded the 27 patients with cam or pincer deformity unaccompanied by other recognized developmental hip conditions. This left 57 patients (58 hips) younger than 18 years of age at the time of a documented diagnosis of developmental or acquired hip pathology. The average age of the patients was 16 years (range, 8–38 years). The minimum followup period was 12 months (average, 41.6 months; range, 12–73 months). No patients were lost to followup prior to the 12-month minimum period. We saw no patients specifically for this study and rather obtained all information from medical records. We obtained prior IRB approval for this study.
WOMAC scores [3
] were noted preoperatively, but WOMAC scores were not obtained in patients with acute trauma or those too young or mentally unable to comprehend the questionnaire. The underlying diagnoses included SCFE (29), Perthes disease (15), and osteonecrosis of the femoral head that was idiopathic or followed femoral neck fractures, SCFE, postfemoral nailing, and sickle cell anemia (eight) (Table ). Symptoms of impingement were present in three patients in the study group who had previously undergone a Salter’s osteotomy for developmental dysplasia of the hip (DDH), growth arrest from treated DDH, and neonatal septic arthritis sequelae, respectively. One patient had a surgical dislocation to facilitate anatomic reduction of an acetabular fracture. An exostosis of the femoral neck was excised in one patient after a surgical dislocation. The procedure was also performed in one patient with protrusio acetabuli.
Many of our patients were referred with complex deformities and had undergone prior procedures. There were 35 prior procedures performed in 33 of the 58 hips (57%) before the surgical dislocation (Table ). Seventeen hips underwent prior pinning for SCFE and two femoral neck fractures were closed reduced and pinned. Two patients with Perthes disease had prior arthroscopy; four had prior intertrochanteric osteotomy, and one had a shelf procedure. A patient with DDH had a prior innominate osteotomy and a patient with protrusio had a prior acetabuloplasty. One patient underwent intramedullary rodding of a femoral shaft fracture that went on to develop femoral head osteonecrosis.
Distribution of procedures performed before surgical dislocation
The following procedures were performed during the index procedure: femoral head-neck junction osteoplasty alone (22), intertrochanteric osteotomy alone (eight), femoral head-neck osteoplasty plus intertrochanteric osteotomy (15), femoral neck osteotomy for stable SCFE and femoral neck fracture nonunion (five), open reduction and internal fixation of unstable SCFE with callus resection (five), open reduction and internal fixation of an acetabular fracture (one), trapdoor procedure (one), and acetabular rim osteoplasty (one) (Table ). One patient with SCFE had bilateral procedures.
Procedures in addition to surgical dislocation of the hip
All surgeries were performed by the senior authors (MBM, YJK) using the following technique. We draped the ipsilateral leg free with the patient in lateral decubitus position and used the surgical approach described by Ganz et al. [4
]. The femoral head, proximal femur, acetabulum, and rim structures were inspected to assess for damage to the labrum and articular cartilage, and any labral tears or chondral flaps were débrided. Dynamic assessment of femoroacetabular contact was performed. In this series, labral repair or refixation was not performed. The hip was then reduced, and the osteoplasty of the metaphyseal prominence was performed. The hip was then carried through another range of motion to assess the effect of the osteoplasty on dynamic impingement. If no concomitant intertrochanteric osteotomy was performed, the greater trochanteric osteotomy was reduced to its bed and fixed in place.
We performed an intertrochanteric osteotomy in 23 patients to reorient the intact articular surface. Blade plate fixation was used, transfixing the trochanteric wafer with the blade of the implant and then inserting the blade into the head-neck fragment. In five patients with unstable SCFE, we performed an open reduction using the technique described by Leunig et al. [9
]. In brief, after performing the trochanteric flip osteotomy and capsulotomy, the thinned periosteum along the anterior femoral neck was visualized. The slip was stabilized using two threaded Kirschner wires. The ligamentum teres was transected and the hip was dislocated anteriorly. We removed the proximal portion of the stable trochanter in a subperiosteal fashion using an osteotome and curettes. The femoral neck periosteum was gently mobilized posteriorly and anteriorly, protecting the vasculature by leaving the periosteal sleeve attached to the femoral head. We then removed the two threaded Kirschner wires and the femoral head was fully mobilized. Posterior callus was resected using a rongeur. We trimmed the femoral neck if we judged necessary until the head with its periosteal sleeve could be reduced anatomically without tension. The epiphysis was then fixed using threaded Kirschner wires and the trochanter reattached.
Postoperatively patients were permitted 1/6th of body weight bearing and placed on precautions that prevented adduction and external rotation for a total of 4 weeks. Passive abduction of 10° was permitted initially and active abduction was encouraged only after the trochanteric osteotomy healed. Flexion was allowed up to 80° and a CPM machine was used when an osteoplasty was done.
Patients were seen 4, 8, and 12 weeks postoperatively by the surgeon and physical therapist and radiographs were obtained to monitor trochanteric union. We obtained postoperative outcomes using the WOMAC questionnaire. The sums of the pain and function domains of the WOMAC questionnaire were recorded. For pain, the scale ranges from 0 to 20, with 0 to 5 considered mild, 6 to 10 moderate, and more than 10 severe. For function, the scale ranges from 0 (no disability) to 68 (extreme disability). Pre- and postoperative WOMAC scores were available in 34 (59.6%) patients and postoperative WOMAC scores were available in 55 patients (96.5%).
We obtained preoperative and postoperative standing anteroposterior pelvic radiographs and bilateral frog leg or true lateral radiographs. Radiographs were utilized to check for healing of the osteotomy and presence of osteonecrosis (GR and YJK). Osteonecrosis was diagnosed by radiographic signs such as increased density of the femoral head followed by eventual collapse. In case of SCFE undergoing capital reduciton, routine bone scans were obtained. Preoperative weight-bearing radiographs were deferred in unstable SCFEs.
Patients having a subsequent THA or hip arthrodesis were deemed failures. Major postoperative complications, such as nerve palsies, infections, nonunions, and hardware failures, were also noted.