Preoperative shoulder dislocations cited as significant risk factor of bone loss
An increased number of preoperative shoulder dislocations is a significant predictor and modifiable risk factor of glenoid and humeral bone loss, according to a presentation at the American Shoulder and Elbow Surgeons Annual Meeting.
“Bone loss is a critical factor in predicting the success of soft tissue stabilization procedures, with bone loss as low as 13.5% of the anterior glenoid resulting in increased recurrence postoperatively,” Carolyn M. Hettrich, MD, MPH, said. “The aim of our study was to understand the risk factors leading to bone loss of the glenoid and of the humerus.”
In their prospective, multicenter study, Hettrich and colleagues analyzed patients who underwent primary anterior stabilization. They used proportional odds models to determine any glenoid bone loss, posterior humeral bone loss or combined glenoid and posterior humeral bone loss. In addition, they assessed patient variables and determined bone loss based on preoperative imaging and interoperative measurements.
Of 895 patients, 52.7% of patients had posterior humeral bone loss, 20.7% of patients had anterior glenoid bone loss and 19.4% of patients had combined glenoid and posterior humeral bone loss. Predictors of glenoid bone loss included older age, male sex, non-white race and contact sport participation.
With each additional dislocation, an 81% increase of bone loss occurred. For glenoid bone loss greater than 10%, any athlete to dislocate a second time would be 257% more likely to have bone loss than one who had a single instability event (OR: 2.57 per dislocation). Predictors of posterior humeral bone loss, or Hill-Sachs lesion, included male sex, non-white ace, presence of anterior apprehension preoperatively and increased number of dislocations. Lesions greater than 10% saw increasing age, as well as increased instability events, as significant predictors of bone loss.
“With significant bone loss, there [are] increased failure rates of up to the 89% in soft tissue stabilization and necessitating bony procedures; while this has not been definitively shown, there may also be an increased risk of post-traumatic arthritis with increased bone loss,” Hettrich concluded. “I would argue that shoulder instability should be viewed similarly to ACL tears, where this is an end-of-season injury for most contact athletes with participation in high-risk activities not recommended until their joint has been stabilized.”