Does Footprint Preparation Influence Tendon-to-Bone Healing After Rotator Cuff Repair in an Animal Model?

PurposeThe aim of this study was to investigate the influence of footprint spongialization and radiofrequency ablation on rotator cuff repair outcomes compared with an untreated group in a rat model.MethodsWe randomly assigned 189 Sprague-Dawley rats to either a spongialization, radiofrequency ablation, or untreated group. After separation of the supraspinatus tendon from the greater tubercle, the footprint was prepared by removing the cortical bone with a burr (spongialization), was prepared by ablating soft tissue with a radiofrequency ablation device, or was left unaltered (untreated). Biomechanical testing (after 7 weeks, n = 165) and histologic analysis after 1 and 7 weeks (n = 24) followed reinsertion.ResultsThe mean load to failure was 17.51 ± 4.46 N/mm2 in the spongialization group, 15.56 ± 4.85 N/mm2 in the radiofrequency ablation group, and 19.21 ± 5.19 N/mm2 in the untreated group. A significant difference was found between the spongialization and radiofrequency ablation groups (P = .0409), as well as between the untreated and radiofrequency ablation groups (P = .0014). There was no significant difference between the spongialization and untreated groups (P = .2456). The mean area of fibrocartilage transition, characterized by the presence of type II collagen, was larger after 1 and 7 weeks in the spongialization group (0.57 ± 0.1 mm2 and 0.58 ± 0.1 mm2, respectively) and untreated group (0.51 ± 0.1 mm2 and 0.51 ± 0.2 mm2, respectively) than in the radiofrequency ablation group (0.11 ± 0.1 mm2 and 0.4 ± 0.1 mm2, respectively) with P < .05 and P < .01.ConclusionsThe results of this study show that radiofrequency ablation of the footprint results in a poor biomechanical and histologic outcome in an animal model. No preparation of the footprint has the same effect as spongialization.Clinical RelevanceDifferent techniques of footprint preparation in rotator cuff repair may influence tendon-to-bone healing.