Surgical Hip Dislocation for Treatment of Slipped Capital Femoral Epiphysis

Abstract

BACKGROUND: Surgical procedures with use of traditional techniques to relocate the proximal femoral epiphysis in the treatment of slipped upper femoral epiphysis are allied with a high rate of femoral head osteonecrosis. Therefore, most surgeons advocate in situ fixation of the slipped epiphysis with acceptance of any persistent deformity in the proximal femur. This residual deformity can lead to osteoarthritis due to femoroacetabular cam impingement.

OBJECTIVE: The primary aim of our study was to report the results of the technique of capital realignment with Ganz surgical hip dislocation and its reproducibility to restore hip anatomy and function.

PATIENTS AND METHODS: This prospective case series study included thirty patients (32 hips, 13 Lt hip, 19 Rt hip) with stable chronic slipped capital femoral epiphysis after surgical correction with a modified Dunn procedure. This study included 22 males and 8 females. The mean age of our patients was 14 years (10-18 years). The mean duration of symptoms before the operation was 4.56 ± 2.5 month. Mean follow up period was 14.5 month (6- 36 months).The mean preoperative Alpha angle was 97.850 ± 13. The mean preoperative Slip angle was 52.50 ± 14.6. Harris hip score was done for all patients pre operatively and its mean was 67 ± 9.3, mean WOMAC score was 88.4 ± 3.8, mean Merle d'Aubigne score was 12 ± 1.

RESULTS: 30 hips had excellent and good clinical and radiographic outcomes with respect to hip function and radiographic parameters. 2 patients had fair to poor clinical outcome including 3 patients who developed AVN. The difference between those who developed AVN and those who didn’t develop AVN was statistically significant in postoperative clinical scores (p = 0.000). The mean slip angle of the femoral head was 52.50 ± 14.6 preoperatively and was corrected to a mean value of 5.6 0 ± 8.20 with mean correction 46.850 ± 14.90 (p = 0.000). Mean postoperative Alpha angle was 51.150 ± 4.2 0 with mean correction of 46.70 ±14.20 (p = 0.000). Post operative flexion was 111.90 ±19.050. Post operative IR in 90 degree flexion was 41.60±9.6. Post operative ER in 90 0 flexion was 45.60 ± 9.97. In our series mean postoperative HHS was (96.16 ± 9.7) and mean improvement was (29.6 ± 9.6) (p = 0.000). Mean WOMAC score was (3.3 ± 3.5) and mean improvement was (85.12 ± 4.7) (p = 0.000). Mean Merle d'Aubigne score was (16.8 ± 2.4) and mean improvement was (4.8 ± 2.4) (p = 0.000) and as regard to Haymann and Hernodon score 30/32 hips were good and excellent results.

CONCLUSIONS: the modified Dunn procedure allows to restor the normal proximal femoral anatomy by complete correction of the slip angle. This tecnique may reduce the probability of secondary osteoarthritis and femoroacetabular cam impingement.