Two hundred three patients with symptomatic hip dysplasia were randomized to receive either isolated peri-acetabular osteotomy (PAO; n=99) or PAO with adjunct arthroscopy (n=104). Outcomes of interest included the international Hip Outcome Tool-33 (iHOT-33) score, the Hip Disability and Osteoarthritis Outcome (HOOS) score, the Patient-Reported Outcomes Measurement Information System (PROMIS) score, and rates of revision and reoperation. Outcomes were assessed pre-operatively and at 6, 12, and 24 months post-surgery. Overall, the results of the study revealed no significant differences in the postoperative outcomes between the two groups at any of the assessed time points. Both groups showed improvements in clinical outcomes and quality of life, suggesting that adjunct arthroscopy may not provide additional benefits when combined with PAO for treating symptomatic hip dysplasia.