title: Clinical and structural outcomes after arthroscopic repair of full-thickness rotator cuff tears with and without platelet-rich product supplementation: a meta-analysis and meta-regression.
abstract: OBJECTIVE
  The purpose of this study was to perform a systematic review, meta-analysis, and meta-regression of all Level I and Level II studies comparing the clinical or structural outcomes, or both, after rotator cuff repair with and without platelet-rich product (PRP) supplementation.
  
  
  METHODS
  A literature search of the PubMed and EMBASE databases was performed to identify all Level I or II studies comparing the clinical or structural outcomes, or both, after arthroscopic repair of full-thickness rotator cuff tears with (PRP+ group) and without (PRP- group) PRP supplementation. Data included outcome scores (American Shoulder and Elbow Surgeons [ASES], University of California Los Angeles [UCLA], Constant, Simple Shoulder Test [SST] and visual analog scale [VAS] scores) and retears diagnosed with imaging studies. Meta-analyses compared preoperative, postoperative, and gain in outcome scores and relative risk ratios for retears. Meta-regression compared the effect of PRP treatment on outcome scores and retear rates according to 6 covariates. Minimum effect sizes that were detectable with 80% power were also calculated for each study.
  
  
  RESULTS
  Eleven studies were included in this review and a maximum of 8 studies were used for meta-analyses according to data availability. There were no statistically significant differences between the PRP+ and PRP- groups for overall outcome scores or retear rates (P > .05). Overall gain in the Constant score was decreased when liquid PRP was injected over the tendon surface compared with PRP application at the tendon-bone interface (-6.88 points v +0.78 points, respectively; P = .046); however, this difference did not reach the previously reported minimum clinically important difference (MCID) for Constant scores. When the initial tear size was greater than 3 cm in anterior-posterior length, the PRP+ group exhibited decreased retear rates after double-row repairs when compared with the PRP- group (25.9% v 57.1%, respectively; P = .046). Sensitivity power analyses revealed that most included studies were only powered to detect large differences in outcome scores between groups.
  
  
  CONCLUSIONS
  There were no statistically significant differences in overall gain in outcome scores or retear rates between treatment groups. Gain in Constant scores was significantly increased when PRPs were applied at the tendon-bone interface when compared with application over the top of the repaired tendon. Retear rates were significantly decreased when PRPs were used for the treatment of tears greater than 3 cm in anterior-posterior length using a double-row technique. Most of the included studies were only powered to detect large differences in outcome scores between treatment groups. In addition, an increased risk for selection, performance, and attrition biases was found.
  
  
  METHODS
  Level II, meta-analysis of Level I and Level II studies.
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, U.S.A.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Warth
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, U.S.A.
authors.forename: Grant J
authors.initials: GJ
authors.lastname: Dornan
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, U.S.A.
authors.forename: Evan W
authors.initials: EW
authors.lastname: James
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, U.S.A.
authors.forename: Marilee P
authors.initials: MP
authors.lastname: Horan
authors.affiliation: Steadman Philippon Research Institute, Vail, Colorado, U.S.A.; The Steadman Clinic, Vail, Colorado, U.S.A.. Electronic address: drmillett@thesteadmanclinic.com.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Millett
mesh_terms: D001182:Arthroscopy; D006801:Humans; D053657:Platelet-Rich Plasma; D017006:Rotator Cuff / Q000503:physiopathology / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012421:Rupture; D013708:Tendon Injuries / Q000503:physiopathology / Q000601:surgery* / Q000628:therapy; D016896:Treatment Outcome; D014945:Wound Healing