Lesions of the Biceps Tendon Diagnosis and Classification

SummaryThis paper presents the clinical signs, radiographic and arthroscopic findings in 23 dogs and a cat having a lesion of the biceps tendon. Several conditions were recognized: partial or complete rupture; avulsion of the biceps tendon from the supraglenoid tubercle, tendinitis, mid-substance tear, bipartite tendon, dislocations and tenosynovitis of the bicipital tendon. Osteoarthritis of the shoulder joint was seen in 84% of the cases and osteophytosis of the bicipital groove was recognized in 38%. Biceps tendon rupture was associated with shoulder joint instability 76% of the time. Shoulder arthroscopy is a very reliable diagnostic method allowing direct visualization of intra-articular pathologies.In man, the tendon of the biceps brachii is the proverbial stepchild of the shoulder. It has been blamed for numerous painful conditions of the shoulder from arthritis to adhesive capsulitis. Kessell described the tendon as “somewhat of a maverick, easy to inculpate but difficult to condemn (1). Its function has been often misunderstood. It has been tenodesed, translocated, pulled through drill holes in the humeral head, and debrided with an arthroscope, oftentimes with marginal results”. Lippmann likened the biceps tendon to the appendix: “An unimportant vestigial structure unless something goes wrong with it” (2). Neer II has stressed the fact that 95 to 98 per cent of patients with a diagnosis of biceps tendinitis have, in reality, a primary diagnosis of impingement syndrome with secondary involvement of the biceps tendon (3). He has condemned routine biceps tenodesis.The veterinary literature on the biceps tendon in dogs is sparse (4-8). Tenosynovitis of the biceps tendon is “a common cause of forelimb lameness in medium and large breed dogs” (7). “Definitive diagnosis of bicipital tenosynovitis is often not possible, and the diagnosis is backed into by eliminating other causes of lameness. Proof of the diagnosis often depends on response to treatment” (7). There are not any reviews of cases of rupture of the tendon of the biceps brachii muscle except for anecdotal case reports (7). Arthrography has been described as diagnostic of rupture (10, 11). Calcifying tendinopathy of the biceps tendon was seen on radiographic views of the scapulohumeral joint in four dogs (9). Twodimensional real-time ultrasonography was found helpful in the diagnosis of strain of the infraspinatus muscle in a dog (12).This paper reviews the pertinent anatomy, explains the function of the biceps tendon, and presents a review of current concepts on the diagnosis of lesions of the biceps tendon.The author presents the clinical signs, radiographic and arthroscopic finding of the disorders of the biceps tendon seen in 25 shoulders. All biceps tendon lesions may be classified in one of the six subtypes. Partial or complete tears are the most frequent pathology. Degenerative joint disease is seen in 84% of the shoulders.