ABSTRACT
PURPOSE: The aim of this study was to objectively evaluate the abnormal gait patterns and gait improvements after a total hip arthroplasty (THA) in patients with hip dysplasia and osteonecrosis of the femoral head (ONFH). MATERIALS AND METHODS: Thirty-four patients (mean age of 43.7 years) with hip dysplasia who underwent THA were divided into the Crowe types (15 type 1, 11 type 2, 3 type 3, and 5 type 4), and gait analyses of these patients were performed using the Vicon 370 motion analysis system. The results of this group were compared with those of 39 age and gender matched patients with ONFH who received a THA and a group of 24 individuals with normal hips. RESULTS: Preoperatively, the gait pattern of the hip dysplasia group did not differ significantly from that of the ONFH group with respect to the temporal gait measurement parameters, kinematics, and kinetics. However, the hip dysplasia group had a different gait pattern than the normal control group and one year after surgery, there were significant differences in the moments and powers of the hip flexors and abductors of patients with severe hip dysplasia (Crowe types 3 and 4) compared with those of the ONFH patients. CONCLUSION: There were less postoperative gait improvements in the patients with severe hip dysplasia than in those with ONFH who had a relatively normal anatomy. These observations might be the result of their weakened hip muscles, particularly the flexors and abductors, despite their increased range of motion after surgery. Perioperative muscle strengthening exercises may be needed to improve gait patterns in patients with hip dysplasia.