Return to Sport After Ulnar Collateral Ligament Tears Treated with Platelet Rich Plasma Injections Is influenced by Length of Rehabilitation and Leukocyte Content of Injections: A Systematic Review.

PURPOSE: To analyze current literature assessing return to sport (RTS) outcomes following platelet rich plasma (PRP) injections for the non-operative treatment of ulnar collateral ligament (UCL) injuries.

METHODS: A systematic review of PubMed, Embase, and Web of Science databases was conducted in June 2023 to identify studies assessing RTS following PRP injections for UCL injuries. Tear severity, leukocyte content of PRP, rehabilitation protocol, and RTS outcomes were collected. Heterogeneity was assessed through proportional random-effects models for RTS and return to pre-injury level of play (RTLP) with subgroup analysis by rehabilitation length, leukocyte content of PRP, and tear severity.

RESULTS: Eight studies with 278 partial thickness and 44 full thickness tears were identified. The mean age of patients ranges from 17.3-26 years. The mean RTS time following injection ranges from 5.2-25.4 weeks. High heterogeneity is observed among studies, with RTS rates ranging from 46-100% (I2 = 83%) and RTLP rates ranging from 34-100% (I2 = 83%). Studies with the longest rehabilitation programs (12-14 weeks) have RTS rates of 87-100% (I2 = 0%). RTS rates among athletes treated with leukocyte poor and leukocyte rich PRP range from 73-100% (I2 = 30%) and 52-88% (I2 = 84%) respectively. Sub-analysis of RTS by tear severity demonstrates high variability, with partial thickness rates ranging from 59-100% (I2 = 55%) and full thickness rates ranging from 27-100% (I2= 63.2%).

CONCLUSION: Studies assessing return to sport following PRP injections are highly heterogeneous; however, current data suggest non-operative RTS and RTLP rates ranging from 46-100% and 34-100% respectively. Studies with at least 12 weeks of rehabilitation and studies utilizing leukocyte poor PRP demonstrate low heterogeneity and higher RTS rates. Alternatively, high heterogeneity is observed among both partial and full thickness tears.

LEVEL OF EVIDENCE: Level IV: Systematic review of level III-IV studies.