Flexible arthroscopy improves anterior visualization of the capitellum compared with a conventional 30° arthroscope: a cadaveric study

BACKGROUND: Arthroscopy of the elbow joint is usually performed with a 30° view. Stability tests, structural assessments and pathologies are described with this scope. Due to the anatomy of the distal humerus and the arthroscopic accessibility, the assessment of the capitellum, particularly with regard to cartilage damage, is limited in terms of dimension and depth. Arthroscopy with flexible optics in the range of 15° to 90° has not been routinely performed. The aim of the study was to investigate whether the use of flexible optics offers advantages in the assessment of the capitellum. METHODS: Eleven fresh-frozen human cadaveric elbows were examined in a standardized free-hanging position with the elbow flexed to 90°. Arthroscopy was performed through the proximal posterolateral portal using a rigid 30° arthroscope and a flexible 15°-90° arthroscope. The most anterior visible margin of the capitellar articular surface was identified and marked arthroscopically for each optic. Following open surgical dislocation of the elbow, the distance between the two markings was measured in millimeters. Paired comparisons were performed using a paired t-test, and effect size was calculated using Cohen's d. RESULTS: In all specimens, the flexible 15°-90° arthroscope provided greater anterior visualization of the capitellum compared with the 30° arthroscope. The mean additional visible distance was 7.0 ± 2.5 mm (95% CI 5.3-8.7 mm). This difference was statistically significant (p < 0.001) with a large effect size (Cohen's d = 2.654). CONCLUSIONS: A flexible 15°-90° arthroscope significantly increased anterior visualization of the capitellum compared with a conventional 30° arthroscope in this cadaveric model. Whether this anatomical visualization gain translates into clinical diagnostic or therapeutic benefit requires further investigation.