We identified 20 throwing athletes who continued to have pain after articular debridement for posterosuperior impingement syndrome. These patients were unable to resume sports, and we subsequently performed a derotational humeral osteotomy with a myorraphy of the subscapularis muscle. Patients were observed for an average of 46 months (range, 12 to 69). Eleven patients were able to resume the same sport at the same level, five resumed the same sport at a lower level, three changed sport secondary to persistent pain, and the last patient did not resume any sport and was worse after surgery. Patients returned to sports at an average of 6 months postoperatively (range, 4 to 44) and to their previous level of sports at an average of 12 months (range, 8 to 18). The mean increase in humeral retroversion was 29 degrees (range, 18 degrees to 44 degrees) Three women with preoperative multidirectional hyperlaxity were considered to have failed results. Derotational humeral osteotomy can be considered in the throwing athlete with posterosuperior impingement after failure of all other means of treatment. Careful patient selection and preoperative evaluation of humeral retroversion is important. Best results can be achieved in a motivated patient with low retroversion (< 10 degrees). If retroversion is normal (20 degrees to 30 degrees), the surgical indication is unclear. We do not recommend this surgery for patients with hyperlaxity.