What Is the Optimal Graft and Transfer Location in Lower Trapezius Tendon Transfer for Posterosuperior Massive Rotator Cuff Tears? A Cadaveric Biomechanical Simulation Study
Ryosuke Iio, Cole T. Fleet, James A. Johnson, George S. AthwalBackground:
Lower trapezius tendon (LTT) transfer can restore shoulder function, particularly active external rotation (ER) following massive rotator cuff tear (MRCT). However, the optimal graft type and its transfer location on the greater tuberosity remain unclear.
Purpose:
To investigate the optimal graft type and location in LTT transfer for posterosuperior MRCT from a biomechanical perspective.
Study Design:
Controlled laboratory study.
Methods:
Eight fresh-frozen cadaveric shoulders were tested on a shoulder simulator. LTT transfer was performed with an Achilles tendon fixed over the superior-middle facets (LTT-Achilles), a semitendinosus (ST) tendon to the superior facet (LTT-ST-S), or to the middle facet (LTT-ST-M). A 24-N load was applied to each transferred graft. Under each condition (intact rotator cuff, MRCT, LTT-Achilles, ST-S, and ST-M), humeral head translation and functional abduction force (FAF) were evaluated at 0°, 30°, and 60° of glenohumeral elevation. ER torque was assessed across 5 angles (60° internal rotation [60IR], 30° internal rotation [30IR], neutral, 30° ER [30ER], and 60° ER [60ER]) at 0°, 30°, and 60° of glenohumeral elevation.
Results:
None of the LTT conditions significantly depressed humeral head posterosuperior migration as compared with MRCT. Compared with MRCT, FAF improved significantly with LTT-Achilles at 0° elevation (
Conclusion:
In LTT transfer for MRCT, LTT-ST-M most effectively restored ER torque, whereas LTT-Achilles and LTT-ST-S improved FAF. None of the conditions of LTT transfer suppressed humeral translation.
Clinical Relevance:
Graft selection and transfer location in LTT transfer can be tailored to patient goals and graft availability, leading to a more patient-specific surgical strategy.