gms | German Medical Science

Objectives: Neglected hip dislocation (NHD) can either be of congenital origin or occur secondary due to septic arthritis (SA) or trauma. If the dislocation has been present for years, closed or open reduction is generally not feasible, mainly because of soft tissue contractures. Leg length discrepancy (LLD) and painful secondary osteoarthritis (OA) severely limit mobility. Even though OA can be addressed through total hip arthroplasty (THA), LLD can hereby be equalized only partially. In case of residual LLD retrograde femoral lengthening can thus be considered.

Methods: A retrospective analysis of radiographs and clinical data of 4 patients (3 female, 1 male) with NHD who had received THA and secondary intramedullary femoral lengthening was performed. In THA, a cementless Trident^® Acetabular System PSL (Stryker, Kalamazoo, MI, USA) was combined with a cementless DiaLoc^® hip stem (Implantcast, Buxtehude, Germany). Femoral lengthening through distraction osteogenesis was performed with a retrograde PRECICE™ lengthening device (NuVasive, San Diego, CA, USA).

Results and Conclusion: 3 hip dislocations were congenital, and 1 secondary due to SA in childhood. Patient data is shown in Table 1 [Tab. 1]. Mean preexisting LLD was 51.3 (45-60) cm. The femoral head was dislocated 50 (15-70) mm proximally. THA was performed at 41 (30-51) years of age. Subtrochanteric shortening osteotomy (SSO) of 53 (50-60) mm was performed in patients with congenital NHD. Mean residual LLD after THA was 36.3 (30-45) mm. Retrograde implantation of a PRECICE™ intramedullary lengthening nail was performed 11.3 (7-19) months after THA. In one patient in whom delayed bone union of the subtrochanteric osteotomy site was observed, additionally autologous bone grafting from the ipsilateral iliac crest and plate fixation of the proximal femur was performed. Distraction was initiated 7 days postoperatively with a distraction rate of 1 mm/day. Mean distraction time was 40.8 (30-52) days. One patient presented 40° flexion deformity of the knee joint after distraction of 20 mm, thus the nail was retracted until full extension was restored and a long-leg plaster cast was applied, within which distraction was resumed. Leg length equalization was achieved in all patients. Mean follow-up after THA was 18.3 (15-26) months.

In patients with NHD, staged reconstruction via THA and secondary femoral lengthening can restore functionality of the hip joint and equalize LLD. However, the specific anatomical conditions have to be carefully taken into consideration when planning treatment, and patients ought to be closely monitored within in the lengthening period to timely detect any occurring complications.

Figure 1 [Fig. 1]