The iliopsoas and adductor tendons are often soft tissue barriers obstructing relocation of the femoral head into the acetabulum and are frequently released to obtain reduction. We assessed whether posteromedial soft tissue release including sectioning of the adductor longus and iliopsoas tendons would lead to alterations in joint angles and moments of the hip joint or other major changes in the gait pattern. We conducted 3-D quantitative gait analysis of 10 patients (mean age, 8.1 years) who had unilateral and surgically treated DDH before the age of 18 months. The mean single support time was shorter in the unaffected side of the patients than in the healthy control group. Mean pelvic excursions in both frontal and sagittal planes and maximum knee extension at stance of the affected and unaffected sides were higher in the patients than in the control group. Peak hip flexion moment during swing phase was somewhat reduced, and the hip moment crossover point from extension to flexion was slightly delayed in both the affected and unaffected sides. We could not identify an explanation for the slight deviations due to limited data. However, sectioning of the adductor longus and iliopsoas tendons in DDH patients under 18 months old did not appear to lead to major objective clinical gait alterations.