Combined Imhauser osteotomy and osteochondroplasty in slipped capital femoral epiphysis through surgical hip dislocation approach

Abstract

Purpose: Treatment of moderate to severe stable slipped capital femoral epiphysis (SCFE) remains a challenging problem. Open reduction by modified Dunn procedure carries a considerable risk of osteonecrosis (ON). Imhauser osteotomy is capable of realigning the deformity without the risk of ON, but the remaining metaphyseal bump is implicated with significant chondro-labral lesions and accelerated osteoarthritis. We conducted this study to evaluate the efficacy and safety of Imhauser osteotomy combined with osteochondroplasty (OCP) through the surgical hip dislocation (SHD) approach.

Methods: A prospective series of 23 patients with moderate-severe stable SCFE underwent Imhauser osteotomy and OCP through SHD. The mean age was 14.4 years (13 to 20) and the mean follow-up period was 45 months (24 to 66). The outcome measures included clinical and radiological parameters and Harris hip score (HHS) was used as a functional score.

Results: The mean HHS improved significantly from 65.39 to 93.3. The limb length discrepancy improved by a mean of 1.72 cm. The mean flexion and abduction arcs showed a significant improvement (mean increase of 37.5° and 18.5°, respectively). The mean internal rotation demonstrated the most significant improvement (mean increase of 38.5°). All the radiographic parameters improved significantly; including anterior and lateral slip angles (mean improvement 37.52° and 44.37°, respectively). The mean alpha angle decreased by 39.19°. The articulo-trochanteric distance significantly increased to a mean of 23.26 mm. No cases of ON or chondrolysis were identified.

Conclusion: Combined Imhauser osteotomy and OCP through the surgical dislocation approach provide a comprehensive and safe management of moderate to severe stable SCFE.

Level of evidence: IV.

Keywords: Imhauser osteotomy; hip impingement; hip preservation; slipped capital femoral epiphysis; surgical hip dislocation.

Fig. 1

Osteochondroplasty and simultaneous pinning through surgical hip dislocation. Femoral head cartilage with trimmed border (asterix), anterior capsular flap tagged with suture (white arrowhead), the head-neck junction after osteochondroplasty and restoring the head-neck offset (white arrow), in situ screw fixation (black arrow).

Fig. 2

a) Imhauser osteotomy in slipped capital femoral epiphysis through surgical hip dislocation approach; b) the seating chisel is inclined in the lateral view to achieve the amount of desired flexion, which corresponds to the bone-plate angle; c) in the frontal plane, the bone-plate angle corresponds to the amount of valgus correction; d) a single transverse cut is performed by a power saw; e) and f) the final corrected head-shaft alignment.

Fig. 3

Preoperative photographs of a 14-year-old child with moderate slip of the right hip, and a partially closed physis: a) limited internal rotation; b) limited flexion; c) fixed external rotation deformity; d) limited abduction.

Fig. 4

Two-year postoperative photographs of the same patient in Figure 3: a) flexion; b) symmetrical abduction; c) abduction against gravity; d) internal rotation in hip flexion; e) symmetrical internal rotation in hip extension.

Fig. 5

a) and b) Right hip slipped capital femoral epiphysis, preoperatively; c) and d) postoperative radiographs after osteochondroplasty, union of Imhauser and trochanteric flip osteotomies, and physeal closure.

Fig. 6

An illustration of the abductor lever arm dysfunction in slipped capital femoral epiphysis (SCFE): a) normally oriented femoral head (FH) with wide horizontal offset of the greater trochanter b) reduced offset in SCFE due to FH retroversion, resulting in reduced abductor lever arm ratio and abductor insufficiency; c) advancing the trochanteric flip to increase the abductor lever arm. The trochanteric flip is advanced anteriorly to the lateral-most point on the trochanteric base.