Sex-related differences in wear patterns in primary elbow osteoarthritis.

Background: We have observed differences in patterns of arthritic wear between male and female patients undergoing arthroscopic management of elbow osteoarthritis. The objective of the study was to examine sex-related radiographic differences in symptomatic primary elbow osteoarthritis through a matched cohort study.

Methods: Fifty patients with primary elbow osteoarthritis that required surgery were identified and divided into two cohorts matched by sex and age from an institutional database. Basic patient demographics were recorded. The minimum joint space width (JSW) of the radiocapitellar and ulnohumeral compartments were measured on coronal and sagittal CT images, by two reviewers.

Results: The mean age of the 50 patients was 56 $\pm 6$ years. The mean size adjusted ulnohumeral JSW for males was 1.5 $\pm 0.4$  mm and females was 1.0 $\pm 0.5$  mm, p = 0.003. The mean size adjusted radiocapitellar JSW for males was 1.1 $\pm 0.6$  mm and females was 1.3 $\pm 0.7$  mm, p = 0.37. Comparing radiocapitellar and ulnohumeral JSW within each sex, radiocapitellar JSW was significantly narrower in males (p = 0.008) but the radiocapitellar and ulnohumeral JSW was similar in females (p = 0.11).

Conclusion: In our study, we found that male patients with primary elbow osteoarthritis had cartilage loss predominantly in the radiocapitellar articulation. Female patients had similar radiocapitellar and ulnohumeral JSW suggesting more symmetric cartilage wear.