Immediate passive mobilization of the hip after internal fixation of acetabular fractures

The authors report the results obtained in 16 patients affected with displaced fracture of the acetabulum treated surgically and mobilized passively immediately after surgery by means of a continuous passive mobilization apparatus for the hip. The age of the patients at the time of trauma ranged from 21 to 54 years. The posterior wall was involved in 12 cases, while the anterior column was also involved in 4. Excellent or good reduction of the fracture was obtained in all of the cases. Immediately after surgery, a continuous passive motion apparatus for the hip was applied to be used for approximately 3 weeks. At final follow-up, which was obtained after a mean time of 5 years, all of the patients except 2 had obtained good results. Moderate joint deficit was present in 1 case, while sciatic nerve palsy that had already been observed prior to surgery persisted in another. Evident radiographic signs of coxarthrosis were not present in any of the cases. Based on the opinion of Salter et al. (1980), who in an experimental study had observed better healing of the cartilaginous lesions in the joints submitted to movement, immediately after surgery we applied a continuous passive motion apparatus for the hip in a group of patients affected with fracture of the acetabulum. As none of the patient followed-up by us presented evident signs of hip arthrosis, the authors hypothesize that continuous passive movement, immediately carried out after osteosynthesis, plays a significant role in preventing post-traumatic arthrosis of the hip. In truth, small irregularities of the acetabular cavity, possibly present after an apparently anatomical reduction, could be minimized by the plasmating effect of the head of the femur in movement.