Long head biceps tenotomy versus tenodesis: a cadaveric biomechanical analysis.

PURPOSE

Treatment of pathology of the long head biceps (LHB) tendon has become an area of renewed interest among orthopaedic surgeons in recent years. Numerous authors have recommended tenotomy, whereas others have recommended tenodesis to avoid distal migration of the LHB tendon stump and the associated cosmetic deformity that may develop. The purpose of the present study was to determine the likelihood of distal migration from the bicipital groove of the long head biceps tendon after tenotomy under physiologic loading conditions and the ultimate load to failure for tenotomized LHB tendons, and to compare these values with those present after tenodesis with an interference screw in a cadaveric model.

TYPE OF STUDY

Anatomic cadaveric biomechanical study.

METHODS

Cyclic loading was performed on 10 cadaveric shoulders through the LHB tendon on an MTS machine (Materials Testing System; MTS Systems Corp, Minneapolis, MN) at a peak force of 50 N (loading rate of 100 N/second) for 200 cycles. After cyclic loading, the specimens were tested to failure at a loading rate of 100 N/second. Failure was defined as migration of the biceps stump distal to the bicipital groove on the proximal humerus. The LHB tendon was then passed back up the bicipital groove and tenodesis was performed in the groove with a bioabsorbable interference screw according to a previously described technique (Arthrex, Naples, FL). Cyclic and load to failure testing were then repeated in similar fashion and the values were recorded and compared with those of the tenotomized subjects (n = 10 in each group).

RESULTS

Four of 10 tenotomized specimens (40%) failed during cyclic loading, with the average number of cycles to failure being 35. The other 6 specimens passed the cyclic test. The average ultimate load to failure in these specimens was 110.7 N. After biceps tenodesis, all specimens passed the cyclic loading test. The average ultimate load to failure in these 10 specimens was 310.8 N. Compared with the 6 tenotomized specimens that passed the cyclic test, the specimens that underwent tenodesis had a significantly higher pullout strength (ultimate strength) with P = .001.

CONCLUSIONS

These results show that, compared with tenodesis, biceps tenotomy results in a significant risk of distal LHB tendon migration and significantly lower load to failure. Cyclic loads similar to those produced by gentle active range of motion without resistance resulted in failure in 40% of specimens tested after an average of 35 cycles. Based on these results, the authors recommend that LHB tenodesis be considered in any patient who may object to the cosmetic deformity and associated dysfunction produced by distal LHB tendon migration after tenotomy.

CLINICAL RELEVANCE

The findings of this study help determine whether to perform long head biceps tenotomy or tenodesis when dealing with long head biceps tendon pathology.