The effect of tenotomy or tenodesis of the long head of the biceps tendon (LHBT) during rotator cuff repair on biceps muscle strength is not well understood. In assessing muscle strength, preoperative muscle strength could be affected by pre-operative pain or cuff tear, therefore the post-operative muscle strength ratio of the affected and contralateral side is calculated. However, previous reports have not been able to eliminate the effects of the presence of rotator cuff tears on the healthy side or of cuff re-tear on the affected side. In this study, we only focused on cases with good rotator cuff healing on the affected side and with no cuff tears on the unaffected side, in order to examine the effect of the LHBT treatment on muscle strength.
This study comprised 104 patients (53 males and 51 females, mean age 65.7 ± 9.1 years) who underwent rotator cuff repair, and had good healing of rotator cuff (Sugaya classifications I and II) on MRI two years postoperatively, and had no complaints and no rotator cuff tears on ultrasonographic evaluation in contralateral side were enrolled. Two years postoperatively, we compared the ratio of elbow flexion strength and forearm supination strength on the affected side to that on the normal side at in the following groups: The control group, comprising 59 patients with normal LHBT and preserved LHBT intraoperatively; the tenotomy group, comprising 27 patients with a pathological lesion of LHBT treated by simple tenotomy; and the tenodesis group, comprising 18 patients with pathological lesion of LHBT treated by tenodesis using interference screw. In addition, we also evaluated the presence of Popeye's deformity and cramping pain.
The strength ratios of elbow flexion and forearm supination of the affected side to the healthy side were 0.96 ± 0.16 and 0.98 ± 0.26 in the control group; 0.92 ± 0.23 and 0.85 ± 0.20 in the tenotomy group; and 0.95 ± 0.12 and 0.98 ± 0.22 in the tenodesis group, with no significant difference between the three groups (p=0.71 and p=0.08). There were 0 cases with Popeye's deformity and upper arm spasm in the control group; 2 (7.4%) and 5 (18.5%) cases in the tenotomy group; and 1 (5.6%) and 1 (5.6%) case in the tenodesis group, respectively.
Some previous studies compared the muscle strength of biceps between tenotomy and tenodesis of LHBT, but the results were controversial. In the present study, the strength ratio of elbow flexion and forearm supination remained the same in both the tenotomy and tenodesis groups, even when cases without LHBT lesions were included in the comparison, suggesting that the presence or absence of LHBT lesions and the difference in treatment methods have little effect on muscle strength.