Biomechanical Comparison of Surgical Techniques for Resection Arthroplasty of the Sternoclavicular Joint

Background: The optimal location and extent of medial clavicle resection for sternoclavicular (SC) joint resection arthroplasty are unknown. Hypothesis: Resection of the intra-articular disc alone cannot reliably decompress the SC joint, and a parallel resection technique will decompress the SC joint significantly more compared with the same amount with an oblique resection technique. Study Design: Controlled laboratory study. Methods: Force transmission through the SC joint was measured in 7 matched-pair human cadaveric SC joints in a dynamic tensile testing machine. The specimens were randomized to either a parallel or an oblique resection technique. An 80-N axial load was applied on the lateral clavicle toward the SC joint in each of the following 4 conditions: (1) intact joint, (2) after resecting the intra-articular disc, (3) after resecting 5 mm of the medial clavicle, and (4) after 10-mm resection. Results: Complete discectomy of all SC joints resulted in a significant reduction of force transmitted through the SC joint (P = .002). However, the varying anatomy of the disc was accompanied by a varying amount of joint decompression (95% CI, 29.8%-65.4%). Resecting 5 mm of the SC joint with the parallel technique decompressed the SC joint by a mean (SD) of 76.7 22.1 N compared with 37.8 +/- 24.8 N with the oblique technique (P = .02). Decompression did not significantly differ between the groups after 10-mm resection (P = .18) using the parallel technique (89.4 +/- 24.1 N) compared with the oblique technique (68.2 +/- 31.6 N). Furthermore, 5-mm resection of the medial end of the clavicle with the parallel technique decompressed the SC joint by an amount similar to 10-mm resection with the oblique technique. Conclusion: Resection of the disc alone did not reliably decompress each SC joint. Resection of 5 mm of the medial end of the clavicle with the parallel resection technique reliably decompressed the SC joint better than with the oblique resection technique. Clinical Relevance: This study provides baseline data on SC joint resection techniques and their mechanical effects. This knowledge can be implemented in clinical practice to treat patients with symptomatic posttraumatic arthritis of the SC joint.