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Study highlights the minimum initial graft tension for double-bundle ACL reconstruction
Researchers of this study note initial graft tension in double-bundle ACL reconstruction could be set as low as 25 N per 6 mm in graft diameter, but caution that tension set at 20 N may result in residual pivot shift.
Researchers evaluated 60 patients who underwent primary double-bundle ACL reconstruction with an autologous semitendinosus tendon. Researchers fixed the bundles to a graft-tensioning system during surgery and set the initial graft tensions to 30 N, 25 N and 20 N. During knee flexion-extension and in response to anterior or rotatory loads, researchers recorded bundle tension. Researchers also measured anterior knee laxity and evaluated the pivot-shift test.
Results showed significantly different tension curves of both bundles among different initial tension settings. Researchers found the highest tension in the 30-N setting and the lowest tension in the 20-N setting. During flexion-extension, the tension in both bundles showed a reciprocal pattern, according to study results.
In response to the anterior load at all settings, researchers found the tension of the posterolateral bundle graft was significantly lower compared with the anteromedial bundle graft. However, results showed equivalent tension in both bundles in response to rotatory loads. Compared with no cases of positive pivot shift in the 25-N or 30-N setting, the 20-N setting had two cases of grade 1 pivot shift. – by Casey Tingle
Disclosures: The researchers report no relevant financial disclosures.