Although subcritical bone loss of greater than 13.5% in patients with posterior instability resulted in lower rates of return to military duty, results published in the American Journal of Sports Medicine showed patient-reported outcomes, complications and reoperation rate were not affected by the level of bone loss.
John M. Tokish
John M. Tokish, MD, and colleagues obtained demographics, return to duty, complications, reoperations and outcomes scores, including the single assessment numeric evaluation (SANE) and the Western Ontario Shoulder Instability Index (WOSI) scores among patients with primary posterior instability who underwent arthroscopic isolated posterior labral repair in a military treatment facility. Researchers used preoperative MRI to calculate posterior glenoid bone loss using a standardized “perfect circle” technique.
All patients had outcomes analyzed based on percentage of posterior glenoid bone loss, and, to determine if bone loss effected outcomes similar to what has been shown in anterior instability, researchers categorized bone loss as below or above the subcritical threshold of 13.5%.
Of 43 patients who presented with primary, isolated posterior instability, 74.4% completed outcome scoring at a mean follow-up of 53.7 months. Results showed a mean posterior glenoid bone loss of 7.3% and no appreciable bone loss in 31% of patients. Researchers noted 22% and 6% of patients had bone loss exceeding 13.5% and 20%, respectively. Although return to full duty or activity was nearly 90% overall, results showed patients were statistically less likely to return to full duty with subcritical glenoid bone loss of greater than 13.5%. However, researchers found no differences in outcome scores, complications and revision rates between patients with no or minimal bone loss vs. patients with more significant amounts of bone loss.
“Clinically significant posterior bone loss is not as common as its anterior counterpart,” Tokish told Healio.com/Orthopedics. “Subcritical bone loss does occur with posterior instability but does not appear to have the same clinical implications as anterior instability does. Future study is necessary to determine the limit at which one should consider bony augmentation.” – by Casey Tingle
: The authors report no relevant financial disclosures.