Background: Long head biceps (LHB) degeneration in combination with rotator cuff tears can be a source of chronic shoulder pain. LHB tenotomy is an approved surgical procedure for pain reduction and improvement of joint function, however, the pathophysiology of LHB degeneration is not fully understood. In the literature, neoangiogenesis in tendon tissue has previously been shown to be associated with tendon degeneration. Vascular Endothelial Growth Factor (VEGF) is an important inducer of neoangiogenesis. The hypotheses are first that an elevated VEGF expression and vessel density can be found in degenerated LHB tissue and second that there is a relation between VEGF expression, vessel density and the different types of rotator cuff tears.
Methods: LHB samples of 116 patients with degenerative rotator cuff tears were harvested during arthroscopic tenotomy. The samples were dehydrated and paraffin embedded. VEGF expression was determined using immunohistochemistry. Vessel density and vessel size were determined on Masson-Goldner stained tissue sections. On the basis of intraoperative findings, patients were assigned to 4 different groups (control group, partial thickness rotator cuff tear, full thickness rotator cuff tear and cuff arthropathy). Partial thickness rotator cuff tears were classified according to Ellman grade I-III, full thickness rotator cuff tears according to Bateman's classification (grade I-IV). The control group consisted of eight healthy tendon samples.
Results: VEGF expression in the LHB was significantly higher in the presence of rotator cuff tears than in healthy tendons (p < 0.05) whereas vessel density and vessel size were significantly higher in the LHB of patients with cuff arthropathy (p < 0.05). Furthermore, there was significantly higher VEGF expression in LHB samples from patients with articular-sided compared to bursal-sided partial thickness rotator cuff tears (p < 0.05). No significant dependence was found between VEGF expression, vessel size and vessel density in LHB of patients with full thickness rotator cuff tears and the extent of the cuff tear following Bateman's classification.
Conclusion: Elevated VEGF expression can be detected in degenerated LHB tissue. The quantity of VEGF expression and vessels are related to the extent of LHB degeneration.