Most patients with developmental dysplasia of the hip (DDH) now receive closed-reduction treatment within 6 months after birth. The long-term outcomes of patients with late-detection DDH have remained unclear. We reviewed the clinical records of 18 patients who underwent Colonna capsular arthroplasty (n=8) or closed reduction (n=10) for developmental dysplasia of the hip as infants or young children and underwent total hip arthroplasty approximately in midlife. Both the Colonna capsular arthroplasty and closed reduction groups achieved good clinical results after total hip arthroplasty. However, the operating time was longer and the improvements of hip range of motion and clinical score were significantly worse in the Colonna capsular arthroplasty group than in the closed reduction group.