Chondral Damage After Arthroscopic Repair Techniques for Acute Bony Bankart Lesions: A Biomechanical Study

Abstract

Background:

Bony Bankart lesions can be encountered during treatment of shoulder instability. Current arthroscopic bony Bankart repair techniques involve intra-articular suture placement, but the effect of these repair techniques on the integrity of the humeral head articular surface warrants further investigation.

Purpose:

To quantify the degree of humeral head articular cartilage damage secondary to current arthroscopic bony Bankart repair techniques in a cadaveric model.

Study Design:

Controlled laboratory study.

Methods:

Testing was performed in 13 matched pairs of cadaveric glenoids with simulated bony Bankart fractures, with a defect width of 25% of the glenoid diameter. Half of the fractures were repaired with a double-row technique, while the contralateral glenoids were repaired with a single-row technique. Samples were subjected to 20,000 cycles of internal-external rotation across a 90° arc at 2 Hz after a compressive load of 750 N, or 90% body weight (whichever was less) was applied to simulate wear. Cartilage defects on the humeral head were quantified through a custom MATLAB script. Mean cartilage cutout differences were analyzed by the Wilcoxon rank-sum test.

Results:

Both single- and double-row repairs showed macroscopic damage. The histomorphometric analysis demonstrated that the double-row technique resulted in a significantly (P = .036) more chondral damage (mean, 57,489.1 µm²; SD, 61,262.2 µm²) than the single-row repair (mean, 28,763.5 µm²; SD, 24,4990.2 µm²).

Conclusion:

Both single-row and double-row arthroscopic bony Bankart fixation techniques resulted in damage to the humeral head articular cartilage in the concavity-compression model utilized in this study. The double-row fixation technique resulted in a significantly increased cutout to the humeral head cartilage after simulated wear in this cadaveric model.

Clinical Relevance:

This study provides data demonstrating that placement of intra-articular suture during arthroscopic bony Bankart repair techniques may harm the humeral head cartilage. While the double-row repair of bony Bankart lesions is more stable, it results in increased cartilage damage. These findings suggest that alternative, cartilage-sparing arthroscopic techniques for bony Bankart repair should be investigated.