Clinical and computed tomography–radiologic outcome after bony glenoid augmentation in recurrent anterior shoulder instability without significant glenoid bone loss

BackgroundThe presence of a significant bony defect in anterior shoulder instability cases warrants glenoid reconstruction surgery typically by means of an autograft. Some surgeons use the same graft techniques even in the absence of a significant bony defect, thus augmenting the glenoid surface. The goal of this study is to investigate the clinical and computed tomography–radiologic outcome after glenoid augmentation surgery.MethodsBetween 2006 and 2011, 11 patients with recurrent anterior shoulder instability and glenoid bone loss of 5% or less were treated with an iliac crest autograft. Of the patients, 9 were available for follow-up at a mean of 34.6 months (range, 12 to 80 months), including apprehension testing, Western Ontario Shoulder Instability Index, Rowe score, Simple Shoulder Value, and 3-dimensional computed tomography examination.ResultsThe mean Rowe score achieved was 85.0 points (range, 51 to 100 points); Simple Shoulder Value, 80.5 points (range, 30 to 100 points); and Western Ontario Shoulder Instability Index, 373.5 points (range, 61 to 878 points). Two patients reported a recurrence of instability, and one featured a positive apprehension test. The mean glenoid surface area was 96.5% (95% confidence interval [CI], 95.5% to 97.4%) preoperatively, increased after graft implantation to 119.5% (95% CI, 105.6% to 133.3%), and decreased to 102.8% (95% CI, 98.6% to 107.1%) at follow-up, concordant to an intact glenoid surface area. From preoperatively to follow-up, the mean increase in glenoid surface area was 6.4% (95% CI, 2.1% to 10.6%; P = .008); in concavity diameter, 2.0 mm (95% CI, −0.9 to 4.9 mm; P = .168); in concavity depth, 0.9 mm (95% CI, 0.3 to 1.5 mm; P = .005); and in concavity retroversion, 2.4° (95% CI, −1.2° to 6.1°; P = .178).ConclusionBecause of anatomic bony remodeling processes, glenoid augmentation surgery seems to be subject to extensive graft osteolysis and, consequently, unsatisfactory clinical outcome in terms of stability in some cases.