Review Article Distal Triceps Rupture Abstract Peter C. Yeh, MD Distal triceps rupture is an uncommon injury. It is most often asso- Seth D. Dodds, MD ciated with anabolic steroid use, weight lifting, and laceration. Other local and systemic risk factors include local steroid injection, L. Ryan Smart, MD olecranon bursitis, and hyperparathyroidism. Distal triceps rupture Augustus D. Mazzocca, MS, MD is usually caused by a fall on an outstretched hand or a direct Paul M. Sethi, MD blow. Eccentric loading of a contracting triceps has been impli- cated, particularly in professional athletes. Initial diagnosis may be difficult because a palpable defect is not always present. Pain and swelling may limit the ability to evaluate strength and elbow range of motion. Although plain radiographs are helpful in ruling out other elbow pathology, MRI is used to confirm the diagnosis, classify the injury, and guide management. Incomplete tears with active elbow extension against resistance are managed nonsurgically. Surgical repair is indicated in active persons with complete tears and for incomplete tears with concomitant loss of strength. Good to excel- lent results have been reported with surgical repair, and very good results have been achieved even for chronic tears. istal rupture of the triceps tendon drome, osteogenesis imperfecta, Dis rare and is among the least rheumatoid arthritis, and type I common of reported tendon injuries. In diabetes.6 Persons with chronic re- a review of 1,014 tendon ruptures, nal disease generally possess ele- 0.8% constituted triceps tendon in- vated levels of parathyroid hormone, 1 juries. In a 6-year span, only 21 cases which stimulates osteoclastic activity of triceps rupture were recorded in the and bone resorption. Such circum- 2 National Football League. There is stances may ultimately predispose to a male predominance of roughly 2 to tendon rupture. Adolescent persons From the Department of 1 in all age groups. with incompletely fused or recently Orthopaedics and Rehabilitation, Most reports have associated tri- fused physes are also susceptible to Yale University School of Medicine, ceps tendon rupture with anabolic triceps tendon rupture.7 New Haven, CT (Drs. Yeh and steroid use and weight lifting.3 Pro- Dodds), New England Baptist Hospital, Boston, MA (Dr. Smart), fessional football players may be at a the University of Connecticut, higher risk for rupture than the gen- Anatomy Farmington, CT (Dr. Mazzocca), and eral population, possibly because of Orthopaedic and Neurosurgery The triceps brachii is a pennate muscle Specialists PC and the ONS the training regimen, the potential Foundation for Clinical Research for steroid use, and the violent with three heads: lateral, long, and me- and Education, Greenwich, CT (Dr. nature of the sport itself.2 Other fac- dial. The triceps extends the entire Sethi). tors that may play a role in distal length of the posterior humerus and is triceps rupture include local steroid the only muscle located in the posterior J Am Acad Orthop Surg 2010;18: 2-4 31-40 injection, metabolic bone diseases compartment of the arm. The triceps is (ie, hyperparathyroidism), renal os- innervated by the radial nerve (C6-C8). Copyright 2010 by the American 5 Academy of Orthopaedic Surgeons. teodystrophy, olecranon bursitis, The lateral head originates from the hypocalcemic tetany, Marfan syn- posterior humerus between the teres mi- January 2010, Vol 18, No 1 31 Distal Triceps Rupture Figure 1 Figure 2 The lateral triceps expansion is marked with a caliper. The olecranon and the triceps tendon proper are dotted with marker. The triceps insertion is not a focal point on the olecranon. Rather, the distal triceps inserts over a wide area or footprint (Figure 1, A through C). In a cadaver study, the footprint was found to start 12 mm distal to the tip of the olecranon (Figure 1, D) and to blend with the posterior capsule; the A, AP photograph of a cadaveric elbow. The triceps footprint on the 2 8 olecranon is outlined with marker. In an anatomic study, the footprint was footprint measured 466 mm . The found to measure 466 mm2.8 B, Lateral view of the triceps footprint. Note the width of the distal triceps tendon in- distance of the proximal portion of the footprint to the articular surface. The sertion ranges from 1.9 to 4.2 cm9 footprint wraps around the tip of the olecranon distally. C, AP view of the tri- and consists of the triceps tendon ceps tendon as it is released from its footprint. The large area of attachment on the tendon itself is clearly visualized (marked in purple). D, The distance proper (ie, the confluence of tendon from the tip of the olecranon to the proximal portion of the footprint is mea- from all three heads inserting on the sured with a digital caliper. In this specimen, that measurement is 12 mm. olecranon) and the lateral triceps ex- pansion (Figure 2). The insertion of the medial aspect nor insertion and the superior aspect of scapula blends with the shoulder cap- of the triceps expansion is located on the spiral groove, the lateral border of sule. The medial head originates on the the posterior crest of the ulna, adja- the humerus, and the lateral intermus- posterior humerus distal to the spiral cent to the medial head. Hypertro- cular septum. The long head originates groove, medial humerus, and medial in- phy of this muscle can cause ulnar at the infraglenoid tuberosity, where the termuscular septum. nerve impingement, a condition that Dr. Dodds or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Integra and Medartis, and serves as a paid consultant to or is an employee of Replication Medical. Dr. Mazzocca or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of, serves as a paid consultant to or is an employee of, and has received research or institutional support from, Arthrex. Dr. Sethi or an immediate family member has received royalties from, is a member of a speakers’ bureau or has made paid presentations on behalf of, and has received research or institutional support from Arthrex. Neither of the following authors nor an immediate family member has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Yeh and Dr. Smart. 32 Journal of the American Academy of Orthopaedic Surgeons Peter C. Yeh, MD, et al is occasionally seen in weight lifters. but this finding is less common. Figure 3 Laterally, the triceps expansion has a Higher-energy mechanisms, such as a wide insertion on the fascia of the motor vehicle accident or a fall from extensor carpi ulnaris muscle and the a height, may also cause concomitant deep fascia of the anconeus muscle.10 ulnar nerve injury and compartment Because of its wide lateral insertion, syndrome; these possible causative 12,13 the triceps expansion often requires factors must not be overlooked. concomitant repair in cases of triceps Regardless of mechanism of injury, rupture. The triceps expansion also triceps tendon ruptures are usually 12 inserts on the antebrachial fascia of seen at the osseous insertion. How- ever, there have been reports of rup- the forearm distally. ture within the muscle belly14 and The distal portion of the medial head tears at the myotendinous junc- Clinical photograph of a palpable has been shown to have a distinct mus- tion.6,15 Fatigue failure of the muscle defect proximal to the olecranon in cle belly and a tendon that is separate a patient with distal triceps rupture. has been suggested as a mechanism from and deep to the common triceps The abrasion just distal to the for intramuscular tears.14 tendon. However, histologic analysis olecranon indicates the area of Patients present with pain and impact during injury. has revealed that the distal expansion swelling over the posterior aspect of of the medial head becomes confluent the elbow. Physical examination re- with the common triceps tendon as they veals tenderness to palpation, swell- lowed to hang down over the edge of insert onto the olecranon.10 This dis- ing, and ecchymosis. A palpable de- the table so that the elbow is flexed tinct insertion may provide the ratio- fect proximal to the olecranon can 90° in a relaxed position. The exam- nale for a distinct medial (proximal) also be apparent and may confirm iner firmly squeezes the triceps mus- repair to achieve anatomic restora- the clinical diagnosis (Figure 3). In cle. The patient with an incomplete tion of the medial insertion, along the acute stage, a defect may not be triceps rupture will be able to extend with primary repair of the lateral palpable secondary to swelling, body the elbow against gravity.18 The pa- head insertion. habitus,16 or the degree of rupture. tient with complete disruption of the The main function of the triceps is The inability to actively extend triceps proper and lateral expansion to extend the forearm at the ulno- against resistance is a sign of com- will not be able to extend the elbow humeral joint. However, because of plete rupture. However, the converse against gravity. its origin at the infraglenoid tuberos- is not always true—that is, not all Fundamental differences between ity, it is believed that the long head complete tears result in the inability the Thompson squeeze test used on of the triceps may also aid in arm ad- to actively extend against resistance. the Achilles tendon and the modifi- duction and extension. The overall This finding is likely secondary to an cation for evaluating the triceps muscle-tendon length of the triceps intact lateral expansion or a compen- could affect the utility of this evalua- critically affects its motor function.