Outcomes are comparable using free bone block autografts versus allografts for the management of anterior shoulder instability with glenoid bone loss: a systematic review and meta-analysis of “The Non-Latarjet”

Purpose: Glenoid augmentation using free bone blocks for anterior shoulder instability has been proposed as an alternative to or bail-out for the Latarjet procedure. The purpose of this investigation was to systematically review and compare outcomes of patients undergoing glenoid augmentation using free bone block autografts versus allografts. Methods: A systematic review using PubMed, MEDLINE, Embase, and the Cochrane Library databases was performed in line with the PRISMA statement. Studies reporting outcomes of patients treated with free bone block procedures for anterior shoulder instability with minimum 2-year follow-up were included. Random effects modelling was used to compare patient-reported outcomes, return to sports, recurrent instability, non-instability related complications, and development of arthritis between free bone block autografts and allografts. Results: Eighteen studies comprising of 623 patients met the inclusion criteria for this investigation. There were six studies reporting on the use of allografts (of these, two used distal tibial, three iliac crest, and one femoral head allograft) in 173 patients and twelve studies utilizing autografts (of these, ten used iliac crest and two used free coracoid autograft) in 450 patients. Mean age was 28.7 ± 4.1 years for the allograft group and 27.8 ± 3.8 years for the autograft group (n.s). Mean follow-up was 98 months in autograft studies and 50.8 months for allograft studies (range 24–444 months, n.s). Overall mean increase in Rowe score was 56.2 with comparable increases between autografts and allografts (n.s). Pooled recurrent instability rates were 3% (95% CI, 1–7%; I² = 77%) and did not differ between the groups (n.s). Arthritic progression was evident in 11% of autografts (95% CI, 2–27%; I² = 90%) and 1% (95% CI, 0–8%; I² = 63%) of allografts (n.s). The overall incidence of non-instability related complications was 5% (95% CI, 2–10%; I² = 81%) and was similar between the groups (n.s). Pooled return to sports rate was 88% (95% CI, 76–96%; I² = 76%). Conclusion: Glenoid augmentation using free bone block autograft or allograft in the setting of recurrent anterior shoulder instability with glenoid bone loss is effective and safe. Outcomes and complication incidence using autografts and allografts were comparable. Due to the high degree of heterogeneity in the data and outcomes reported in available studies, which consist primarily of retrospective case series, future prospective trials investigating long-term outcomes using free bone block autograft versus allograft for anterior shoulder instability with glenoid bone loss are warranted. Level of evidence: IV.