Gait Analysis of Leg Length Discrepancy-Differentiated Hip Replacement Patients With Developmental Dysplasia: A Midterm Follow-Up.

BACKGROUND: Few studies investigate gait characteristics and symmetry of developmental dysplasia of the hip patients (Crowe II and III) after total hip arthroplasty (THA) whose leg length discrepancy (LLD) is within 20 mm. Our study aimed to explore whether gait analysis parameters in these patients can return to the level of unaffected people and how bodies compensate for the discrepancy.

METHOD: A total of 45 patients who underwent cementless THA and 20 healthy controls were involved in this study prospectively. Group 1 includes patients whose LLD is <10 mm and group 2 includes patients whose LLD is 10-20 mm. Gait analysis was performed during 5-year midterm postoperative follow-up.

RESULT: The parameters, particularly the range of motion (ROM) in the hip, in both experimental groups (1 and 2) were significantly lower than healthy control group. For the nonoperated side, group 1 displayed significantly reduced ROM in the hip and knee compared with the age-matched controls. This was not observed in group 2. Greater bilateral symmetry can be seen in group 1 compared with group 2.

CONCLUSION: Despite LLD being limited to within 20 mm, THA patients in both groups showed a less efficient gait than that of healthy controls on 5-year midterm follow-up. The increased ROM in the nonoperated hip may act as a compensatory mechanism. LLD of 10 mm may be a cutoff value to assess whether compensation occurs in the contralateral limb. Reconstruction of equal limb length is recommended when surgeons perform THA for dysplastic hips.