New classification system for glenoid bone loss uses type of bone defect, attrition

SEATTLE — Glenoid bone loss is highly attritional and the remaining bone fragments may not be sufficient enough to reconstruct glenoid bone stock in patients with anterior instability, according to a presenter at the American Orthopaedic Society for Sports Medicine Annual Meeting.

“There is quite a bit of bone missing [in these cases] in terms of putting this back for repair and not enough to reconstruct the native glenoid in the vast majority of cases in our cohort,” said Matthew T. Provencher, MD, here.

Provencher and colleagues studied a new glenoid bone loss classification system which considers the type of bone defect, amount of attritional loss as correlated to age, total time of instability and number of instability events. Overall, 140 patients with recurrent anterior instability and a mean age of 30.6 years underwent 3-D CT imaging to assess the amount of glenoid bone loss. The bone fragments were digitally analyzed to evaluate each patient based upon attrition. The evaluations were classified as type 1 (no attrition to 33% attrition), type 2 (34% attrition to 66% attrition), and type 3 (67% attrition to 100% attrition). The researchers evaluated patient age, total time of instability and the number of instability events.

Mean glenoid bone loss was 16.5% and the mean size of the remaining glenoid bone fragment was 27.8% of the original. Type 1 attritional bone loss was found in 12 patients, type 2 in 45 patients, and type 3 in 83 patients. The average glenoid bone loss for type 1 was 22.2%, type 2 was 54.4%, and type 3 was 88.5%. Longer time of instability and multiple dislocations were related to both type 3 bone loss and higher attrition of bone loss. —by Christian Ingram

Reference:

Provencher MT. Paper #4. American Orthopaedic Society for Sports Medicine Annual Meeting; July 10-13, 2014; Seattle.

Disclosure: Provencher is a paid consultant for Arthex and Joint Restoration Founders.