Abstract
Introduction: The objective of this study was to evaluate the structural properties of the native IOL and three different constructs for IOL reconstruction.
Methods: 24 fresh-frozen (FF) forearms, 6 FF Achilles (ACH) allografts, and 6 FF bone-patellar tendon-bone (BPTB) allografts were used. N=6 FCR, ACH, and BPTB reconstructions were performed at the angle of the native IOL. For the FCR and ACH constructs, 5 mm tunnels were drilled across the radius and ulna, the graft ends were sutured with a baseball stitch (#2 braided polyester), passed, cyclically pretensioned, and tied to suture posts under maximal manual tension. For the BPTB construct, troughs were created in the dorsal radius and ulna, and the bone blocks were secured in the troughs under maximal manual tension using 3.5 mm cortical lag screws.N=8 native IOL’s and N=6 each of the reconstruction constructs were resected from the forearms attached to 6 cm segments of radius and ulna.Specimens were potted and mounted on an Instron using custom clamps.
One-way ANOVA was used to compare results with p=0.05.
Results: The intact IOL was significantly 7–8 times stiffer than FCR/ACH and 3 times stiffer than BPTB constructs. Strength of the intact IOL was 3 to 4 times higher than FCR, ACH and BPTB constructs. No significant differences were detected between any properties of FCR and ACH grafts. BPTB displayed significantly greater structural properties compared to ACH and FCR.The load-elongation curves for the intact IOL displayed toe and linear regions, and abrupt failure typical for ligaments.
Discussion-conclusions:The graft constructs were structurally inferior to the native IOL. Achilles and FCR grafts were similar biomechanically, while BPTB displayed slightly higher properties. The BPTB reconstruction applied dorsally was observed to tighten in pronation, and become slack in supination, likely because these were dorsal to the interosseous ridge. It is important to note that all properties would be influenced by healing and remodeling in living subjects.
ACH and FCR reconstruction constructs were similar, but inferior to the intact IOL. BPTB was slack in supination. What remains unknown is how stiff an IOL reconstruction should be to provide a beneficial effect on forearm biomechanics. IOL reconstruction remains an experimental procedure.
The abstracts were prepared by Eleni Koutsoukou. Correspondence should be addressed to him at the Hellenic Association of Orthopaedic Surgery and Traumatology (HAOST), 20, A. Fleming str, 15123 Marousi, Athens, Greece.
