CT-scan Evaluation of Osteointegration and Osteolysis in Different Graft Types and Surgical Techniques for the Treatment of Shoulder Instability

Bone graft is often needed in treating anterior shoulder instability in glenoid bone loss and graft integration is crucial in achieving good results. This study aimed to evaluate bone graft remodeling in different techniques for shoulder anterior-inferior instability.  Graft osteointegration and osteolysis were retrospectively evaluated with CT-scan imaging performed 6 to 12 months after surgery to compare the outcome of three procedures: Latarjet, bone block with allograft, and bone block with xenograft. Screw fixation and double endobuttons fixation were also compared.  CT scans of 130 patients were analyzed. Of these, 30 (23%) were performed after the bone block procedure with xenograft and endobuttons fixation, 55 (42%) after the bone block procedure with allograft and endobuttons fixation, 13 (10%) Latarjet with screw fixation and 32 (25%) Latarjet with endobuttons fixation. The prevalence of osteolysis was significantly inferior (P<.01) in the bone block procedure compared to the Latarjet procedure (11.7 % vs. 28.8 %). Bone integration was higher in bone block procedures (90.5%) than in Latarjet (84.4%), but the difference was not statistically significant. Among the Latarjet procedures, endobuttons fixation resulted in a higher integration rate (87.5% vs. 73.6%) and lower osteolysis rate than screw fixation (24.6% vs. 38.5%), despite these differences did not reach a statistical significance. Among the bone block procedures, using a xenograft resulted in a lower osteolysis rate (6.7%) than an allograft (14.5%), but the result was not statistically significant.  This study shows a significantly lower rate of graft osteolysis after bone block procedures compared to Latarjet procedure between 6 and 12 months postoperatively. Moreover, our findings suggest good results in osteolysis and graft integration with xenograft compared to allograft and double endobuttons fixation compared to screw fixation, despite these differences being not-significant. Further studies on this topic are needed to confirm our results at a longer follow-up and thoroughly investigate the clinical relevance of these findings.Level of evidence: III