Biomechanical Evaluation of Distal Radioulnar Joint Instability and Adams Procedure.

PURPOSE: Distal radioulnar joint (DRUJ) instability may occur after an injury, resulting in pain and reduced strength. When primary repair is not possible or initial fixation has failed, chronic instability may result, requiring a reconstructive procedure such as the Adams procedure. The first purpose of this study was to evaluate the role of the triangular fibrocartilage complex and various components of the interosseous membrane as they were sectioned. The second purpose was to evaluate the Adams procedure in stabilizing the forearm. METHODS: Eight fresh cadaver forearms were dynamically moved through an average range of 56.8° pronation to 54.8° supination and tested first with the forearm intact and then after sectioning each of the following structures: the dorsal (DRUL) and palmar radioulnar ligaments (PRUL), the distal interosseous membrane, and the central band. Finally, they were tested after reconstruction using the Adams procedure. During each forearm motion and provocative shuck, the motion of the radius and ulna were measured and the locations of the radial attachments of the DRUL, PRUL, and sigmoid notch and ulnar fovea were computed. RESULTS: Significant increases in the gap between the ulnar fovea and the attachment sites of the DRUL and PRUL were observed with incremental sectioning, most notably after sectioning of the central band. Reconstruction significantly reduced the gap at the DRUL and PRUL sites during dynamic motion. CONCLUSIONS: This study reinforces the concept that DRUJ stability depends on more than the radioulnar ligaments, ulnocarpal ligaments, and triangular fibrocartilage complex, but is also significantly affected by the distal and central interosseous membrane. Reconstruction reduces gapping. CLINICAL RELEVANCE: These results suggest that the Adams reconstruction is a reasonable option to address DRUJ instability but may be an incomplete solution in the setting of a ruptured interosseous ligament.

Quantification of thermal spread and burst pressure after endoscopic vessel harvesting: a comparison of 2 commercially available devices.

OBJECTIVE: Endoscopic vein harvesting systems have grown in popularity and are becoming the gold standard for coronary artery bypass grafting. Although a consensus is present that endoscopic vessel harvesting minimizes wound complications, long-term graft patency remains a concern. It has been proposed that endoscopic vessel harvesting affects graft patency because of irreversible trauma to the endothelium. This study was performed to examine the extent of thermal injury caused by 2 commercially available endoscopic vessel harvesting systems in a porcine model. METHODS: Superficial epigastric veins and saphenous arteries were exposed in 10 anesthetized swine. All vessel samples (conduits) were harvested randomly with either a VirtuoSaph (Terumo Cardiovascular, Ann Arbor, Mich) or VASOVIEW 6 (MAQUET, Inc, Wayne, NJ) endoscopic vessel harvesting system. Conduits were harvested and saved for either histologic analysis or burst-pressure test. Statistical differences were analyzed by using a Wilcoxon rank sum test in SAS 9.2 software (SAS Institute, Inc, Cary, NC) for thermal spread and a 2-tailed t test with equal variance for burst pressure. RESULTS: The average thermal spreads for saphenous artery and superficial epigastric vein conduits were significantly shorter in the VirtuoSaph group (0.42 ± 0.08 and 0.49 ± 0.05 mm, respectively) than in the VASOVIEW 6 group (1.05 ± .04 and 0.94 ± 0.19 mm, respectively). No significant differences were observed in burst pressure. CONCLUSIONS: The length of thermal spread is short in arterial and venous conduits (0.4-1.1 mm) and depends on the endoscopic vessel harvesting system. Clinical protocols should include a minimal length of the cauterized branch to ensure that thermal spread does not reach the main vessel. The results of this study suggest that at least 1 mm is sufficient.