Summary

Anterior L-shape supraspinatus repair with long head bicep augmentation obtains the normal shoulder mechanics.

Abstract

Background

Long head biceps tendon (LHB) augmentation is one of the treatment options for anterior L-shaped supraspinatus tear. This study aimed to compare the biomechanics of shoulder with partial supraspinatus (SSP) repair and intact shoulder.

Materials And Methods

Sixteen soft cadaveric shoulders with intact rotator cuff and LHB were recruited, randomized and tested biomechanically in a custom shoulder testing system in 4 different testing conditions: intact SSP; anterior L-shape SSP tear; partial repair SSP and LHB augmentation. Abduction and total rotational range of motion (ROM), subacromial peak contact pressure, subacromial contact area, and superior humeral translation were measured at 0⁰, 30⁰, 60⁰ glenohumeral abduction in scapular plane.

Results

Anterior L-shape supraspinatus tear showed higher significant difference for total rotational range of motion (ROM) at 0⁰, 30⁰, 60⁰ compared to intact SSP (64.2+10.0 vs 85.7+10.0, p=0.013; 84.7+10.0 vs 103.7+10.0, p=0.028; 94.2+10.0 vs 113.710.0, p=0.024 respectively). Glenohumeral abduction with LHB augmentation can restore back total rotational range of motion to normal at 30⁰, 60⁰ (102.4+10.7, p=0.067 and 103.6+10.7, p=0.330 respectively). Both repair techniques had the same results in restoring subacromial peak contact pressure and subacromial contact area. LHB augmentation maintained the superior humeral translation as same as intact SSP (1.87+0.63 vs 1.77+0.67, p=0.807; 1.70+ 0.63 vs 2.32+0.67, p=0.743 respectively). Although the peak contact pressure in partial repair obtained higher than LHB augmentation but insignificantly difference.

Conclusion

LHB augmentation can restore rotational range of motion and bring back the superior stability to humeral head. This augmentation technique is one of the surgical options for anterior L-shaped SSP tendon tear with intact LHB.

Key words
anterior L-shaped supraspinatus tear, long head biceps augmentation, partial repair