Study of the Biceps Fatigue after Surgery on the Long Head of Biceps Tendon in Male Heavy Workers. A Prospective Randomized Clinical Trial Comparing Biomechanics and Clinical Outcomes after Tenotomy Versus Tenodesis

SUMMARY The aim of this study was to evaluate biceps fatigue and strength after tenotomy vs tenodesis of the LHBT. The hypothesis was that there may be differences when analyzing biceps fatigue between both techniques. Methods. 70 male heavy workers were initially enrolled to perform a biomechanical study. Preoperatively and 12 months after surgery a maximum elbow flexion force (MVC) and forearm supination test (MVS) were analyzed. Subsequently, a biceps fatigue test was performed by a submaximal contraction to 33% of MVC maintained until claudication. After the claudication, the MVC and MVS were measured again. In addition, the Constant score, SSI functional scale, VAS scale and perceived symptoms were evaluated. 45 patients met de inclusion criteria and were randomized into tenotomy or tenodesis group. 41 of them were followed-up for at least one year. Results. There were no differences between groups at the end of the follow-up in MVC (246.81 ± 57,4 vs 273.69 ± 58,8 N) nor in MVS (50,73 ± 6,31 vs 177.7 ± 71.6 Nm). The fatigue test was statistically shorter in the tenotomy group (95.18 ± 28.8 vs 122.53 ± 42.1 s). Popeye sign was higher in the tenotomy group. There were no differences in postoperative pain, function scales, groove pain or biceps cramps. Conclusions. The usual biomechanical study using maximum flexion or supination force has not seen differences, while the study of biceps fatigue has found them. The study of biceps fatigue is necessary to analyze the differences that with the standard study of maximum strength could be hidden. KEY WORDS Tenotomy; tenodesis; long head of biceps tendon; biomechanics; supination; fatigue.