The aim of this study is to compare cyclic loading and ultimate strength between new transosseous repair technique (NTO), conventional transosseous repair (CTO) and transosseous equivalent repair (TOE).
Rotator cuff repair is the standard treatment of symptomatic reparable rotator cuff tear. Among various repair techniques, TOE with double row equivalent suture anchors become more favorable because of strong construct and easier fixation technique by arthroscopic mean. However, due to the cost of TOE which is more expensive from multiple anchors used, the open approach CTO was still an option in some primary cases or revision cases. To combine the advantage of both techniques, the NTO was developed for easier fixation using arthroscopic approach. The biomechanical study was then performed to compare the strength of all fixation technique.
Twenty-seven porcine shoulder specimens were randomized into 3 groups (NTO, CTO and TOE). After infraspinatus tendon was detached and repaired by each technique, biomechanical testing was performed with initial preload, cyclic loading and ultimate strength respectively. Partial tear (tendon elongation > 5 mm) and complete tear(tendon elongation > 10 mm) were observed after cyclic loading test. Finally, ultimate strength and mode of failure were recorded.
After cyclic loading, there was no significant difference between three groups in term of numbers of cycle that partial tear or complete tear observed (p-value= 0.45, 0.45 respectively). The ultimate load of CTO, NTO and TOE group were 264.7±61.2, 297.0±91.3, 260.5±64.0 respectively (mean±SD) with no significant difference. Type 2 and 3 of failure mode were observed in CTO and NTO group whereas TOE group also had type 4 of failure mode (dislodge of suture from the lateral row anchor).
NTO repair achieved strong fixation comparable to CTO and TOE repair with less suture passing (compare to CTO) and lower cost (compare to TOE).