Rupture of the triceps tendon is rare.^1,2,3 Anzel et al.⁴ reported that 85% of the 1,015 tendon injuries treated at the Mayo Clinic involved the upper extremity. Of this group of 856, only eight instances of triceps tendon injury were reported, and four of these were due to laceration. Since the first report of Partridge⁵ in 1868, as of 2000, fewer than 50 instances have been recorded in the English literature.^6,7,8,9 Unlike ruptures of the distal biceps tendon, this may occur both in men and women with a female to male ratio of 2:3. The mean age of occurrence is about 33 years, but rupture has been observed in a broader spectrum of ages including children (aged seven) to adolescents in whom the olecranon physis has just closed,¹⁰ to individuals in their eighties.¹¹

Rupture of the triceps tendon may occur either spontaneously, after trauma, or after surgical release and reattachment. Two types of traumatic episodes may be implicated. The most common event is a deceleration force imparted to the arm during extension as the triceps muscle is contracting. This usually occurs during a fall, but avulsion has been reported due to simple, uncoordinated triceps muscle contraction against a flexing elbow.^12,13 The association of triceps tendon avulsion¹⁴ or tear⁷ associated with body builders is consistent with the observation of muscle unit damage associated with eccentric contractures in the unconditioned muscle.^15,16 The possibility of anabolic steroid usage must also be considered in this type patient. A direct blow to the posterior aspect of the triceps at its insertion in varying positions also has been reported in several instances^17,18,19 but is probably an uncommon mechanism of injury.

Triceps rupture is uncommon in body builders and is much less common than distal biceps rupture. Clayton¹¹ has suggested that olecranon bursitis may predispose to triceps tendon rupture. Disruption of the triceps also may occur spontaneously with minimal trauma in individuals who are compromised by a systemic disease process,²⁰ such as with renal osteodystrophy and secondary hyperparathyroidism.^21,22 Although the pathophysiology of this association has not been completely explained, an increased amount of elastic fibers in the tendons of patients with renal osteodystrophy undergoing dialysis has been reported.²³ Calcification due to the chronic hypercalcemia of secondary hyperparathyroidism may be yet another explanation for the associated tendon ruptures in this group of patients.²⁰ Ruptures also have been reported in association with steroid treatment for lupus erythematosus¹⁹ and chronic acidosis,²³ in individuals with osteogenesis imperfecta tarda,²⁴ and with Marfan syndrome.²⁵ Diabetes has been recently implicated in a patient with triceps rupture at the musculotendinous junction.²⁶ Triceps deficiency occurring after total elbow replacement is obviously a problem of exposure, and repair and is discussed elsewhere.