Suture anchor reinsertions of distal biceps rupture: a histologic analysis of a torn tendon and clinical results at short- and long-term follow-up

Abstract

Background: Distal biceps brachii tendon (DBBT) rupture is a relatively rare injury. Nonsurgical treatment determines 30%-40% power loss of elbow flexion and up to 50% of forearm supination. Therefore, refixation of the DBBT is recommended. The DBBT is exposed to tension and compression loading. It is known that the tendon under compression might develop fibrocartilaginous metaplasia that improves the resistance to compression but reduces the resistance to tension. To test this hypothesis, the present study evaluated the presence of cartilage in DBBT samples. Furthermore, the present study evaluated the clinical and functional outcomes of anatomic reinsertion through suture anchors in a cohort of patients after 1, 3, and 5 years of follow-up.

Methods: Between 2011 and 2014, 21 patients with DBBT tear underwent a suture anchor reattachment. Histochemical and immunohistochemical analysis of torn samples of DBBT collected at the time of surgical repair were performed to test the presence of cartilage. During the follow-up examination, mobility, elbow radiographs, Mayo Elbow Performance Score, and isokinetic analysis were prospectively evaluated.

Results: Fibrocartilage was detected in all tendon samples collected. Two cases of transient paresthesia in the lateral antebrachial cutaneous nerve occurred, but they resolved in 6 weeks. There were no vascular deficits, re-ruptures, radioulnar synostoses, or infective complications at follow-up. Three patients reported loss of supination. Mayo Elbow Performance Score showed good and excellent clinical and functional results. No significant differences about strength and fatigue in flexion-supination were recorded between the surgical and contralateral side at 3 and 5 years of follow-up. Arm dominance influenced supination but not flexion.

Conclusion: On the basis of our results, we find that the presence of cartilage metaplasia might make the DBBT at higher risk of rupture assuming the compression loading and the hypovascular zone of the tendon. However, concerning the lack of histologic analysis of the healthy DBBT, its role in tendon pathology remains to be clearly defined. The technique of suture anchor reinsertion by a single incision was shown to be safe, with few complications and good functional results at 5 years of follow-up. No significant differences were reported between the injured and noninjured side in terms of flexion and supination isokinetic analysis, whereas arm dominance had a positive effect on supination.

Keywords: Cartilage metaplasia; compression loading; distal biceps brachii; hypovascular zone; suture anchor; tendinosis.