Unilateral and bilateral neurogenic dislocation of the hip joint--which deformity is more difficult to treat?

Authors present and compare the results of treatment of spastic hip dislocation in a group of patients with unilateral or bilateral dislocation.

We analyzed a group of 77 patients (109 hips) with a dislocated hip joint (MP>80%). The patients were divided into Group 1 (47 hip joints, 47 patients) with unilateral dislocation and Group 2 (62 hips, 31 patients) with bilateral dislocation. The mean duration of follow-up was 2.5 years (range 1.2-7.5) in Group 1 and 3.4 years (1.2-10.2) in Group 2. The hips were evaluated clinically and radiographically in the pre- and post-operative period. The relation of the femoral head to the acetabulum was described as the Acetabular Index (AI) and Reimers' migration percentage (MP). The Pelvic Femoral Angle (PFA) was used to measure the degree of windblown deformity.

There were three cases of post-operative redislocation (MP>80%) and four cases of severe subluxation (MP>50%) in Group 1 compared to no dislocations in Group 2. In Group 1, AI improved from 31.3°(20°-50°) to 22.7°(3°-50°) and MP improved from 98.8% (85%-100%) to 23.4% (0%-100%). In Group 2, AI improved from 30.5° (10°-62°) to 19.9° (4°-40°) and MP improved from 98.8% (82%-100%) to 9.6% (0%-60%). In Group 1, PFA before surgery was -10.3° (-40° to 10°) for the dislocated side and 6.6° (-16° to 55°) for the non-dislocated side and after surgery it was -5.7° (-46 to 45) for the treated side and 5.6° (-18° to 45°) for the untreated side. In Group 2, PFA was -3.1° (-22° to 9°) before surgery and -0.15° (-18° to 25°) after surgery. We found improved ranges of motion for the movements investigated.

The clinical and radiological results of operative treatment presented in this paper allow for the conclusion that patients with unilateral dislocations run a higher risk of redislocation, subluxation, and windblown deformity.