Predicting impinging osteophytes based on pre-operative simulation results to guide arthroscopic débridement for elbow osteoarthritis.

Background: In arthroscopic surgery for elbow osteoarthritis, decisions regarding the size and location of osteophytes to be removed often depends on the surgeon's experience. The purpose of this study was to predict impinging osteophytes based on pre-operative simulation results. Methods: In total, 92 elbows with osteoarthritis were examined. Computed tomography was performed in maximum extension, 90°, and maximum flexion positions. Bone models were constructed and the rotational axes were calculated. The forearm bones were rotated around these axes to simulate the 0° and 140° positions, with the overlapping regions identified as impinging osteophytes. The sizes of the osteophytes were measured, and the relationship between osteophyte size and pre-operative range of motion was investigated. Results: For the 0° simulated position, sizes of impinging osteophytes were 6.4 ± 0.4 mm at the posteromedial humeroulnar joint, 4.2 ± 0.3 mm at the posterolateral humeroulnar joint, and 2.2 ± 0.2 mm at the posterior capitellum. Osteophyte size was negatively correlated with the extension at the posteromedial humeroulnar joint (R = -0.48, Y = -0.16X + 2.52). For the 140° simulated position, sizes of osteophytes were 6.7 ± 0.4 mm at the anterior humeroulnar joint and 2.0 ± 0.2 mm at the radial fossa. Osteophyte sizes were negatively correlated with flexion (R = -0.45, Y = -0.14X + 23.23 at the anterior humeroulnar joint; R = -0.46, Y = -0.08X + 11.20 at the radial fossa). Conclusion: Osteophytes are associated with the pre-operative range at the posteromedial humeroulnar joint, anterior humeroulnar joint, and radial fossa. These results can be used as an index to determine the osteophytes to be removed during arthroscopic surgery for elbow osteoarthritis.