This randomized controlled trial will compare proximal femoral resection-interposition arthroplasty to proximal femoral resection with subtrochanteric valgus osteotomy for the treatment of painful irreducible hip dislocation in patients with cerebral palsy. The primary outcome is quality of life and care giver burden measured by The Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) score at one year. Secondary outcomes will include pain (NCCPC-R, PROMIS pain intensity and PROMIS pain interference), function (mobility questions), complications and surgical parameters such as OR time and fluoroscopy time. A cost-effectiveness analysis will follow completion of the randomized controlled trial (RCT). The authors hypothesize that mean CPCHILD scores (measured at 1 year) will be significantly higher following the Subtrochanteric Valgus Osteotomy technique compared to Proximal Femoral Resection-Interposition Arthroplasty technique. Furthermore, the Proximal Femoral Resection-Interposition Arthroplasty technique will have a shorter length of hospital stay, shorter fluoroscopy and OR times and the Subtrochanteric Valgus Osteotomy will have longer sitting tolerance, less pain, smaller burden for caregivers, better health, and higher quality of life. Additionally the authors hypothesize that Subtrochanteric Valgus Osteotomy will be more expensive than Proximal Femoral Resection-Interposition Arthroplasty, due to the cost of the plate, longer operative time, longer length of stay, and blood loss, but Subtrochanteric Valgus Osteotomy will be preferred by patients due to less pain and better functional and quality of life outcomes.The results of this study are expected to improve outcomes for children with cerebral palsy with painful irreducible dislocated hips.