Triceps Tendon Avulsion

As its name suggests, the triceps muscle has three heads of origin, as follows:

• The long head arises from the infraglenoid tubercle of the scapula
• The lateral head arises from the posterior surface of the humerus above the radial groove and partly from the lateral intermuscular septum
• The medial head originates from the entire posterior surface of the humerus below the radial groove—from the medial and lower parts of the lateral intermuscular septum; it joins the deep surface of the combined long and lateral heads and forms the strong and broad triceps tendon

The triceps tendon inserts, for the most part, into the posterior portion of the upper surface of the olecranon. However, a band of fibers continues downward, on the lateral side, over the anconeus, to blend with the deep fascia of the forearm. This entire muscle complex is the only real extensor at the elbow joint.

Disruption of the triceps can occur in one of the following three anatomic locations, listed in decreasing order of frequency:

• Attachment of the tendon to bone
• Musculotendinous junction
• Muscle substance

Tarsney stated that disruption of the triceps at its insertion into the olecranon is most accurately termed avulsion of the triceps and that the term rupture should be used to describe intramuscular or musculotendinous disruption of the triceps.[6]

Clinical evidence suggests that avulsion fracture of the olecranon is related to olecranon ossification center healing.[7]

Avulsion or rupture of the distal triceps tendon most often occurs after trauma. Indirect trauma is the most common cause of injury and usually involves a fall onto an outstretched arm, with resultant pain about the elbow. This mechanism places a deceleration stress on a contracted triceps muscle, with or without a concomitant blow to the posterior aspect of the elbow. The result is a distal avulsion at the tendino-osseous insertion. The tendon usually retracts, and bone from the proximal olecranon becomes embedded in it.[8, 5]

Avulsion has also been reported after an isolated blow to the elbow alone.[5] In rare instances, ruptures of the midsubstance belly and musculotendinous junction have occurred.[9] Spontaneous avulsion of the distal triceps tendon has been reported in patients with hyperparathyroidism, osteogenesis imperfecta, Marfan syndrome, systemic lupus erythematosus, or systemic treatment with steroids.[5, 10, 11, 12]

In addition, review of the literature reveals a growing population of patients with chronic renal failure who are receiving dialysis, have secondary hyperparathyroidism, or both. These patients appear to be at increased risk for tendon injury after minor trauma.[5, 13]

The mechanism described above for distal triceps tendon avulsion may also cause the relatively less common transverse or oblique avulsion fracture through the proximal olecranon. A high incidence of fractures of the proximal olecranon is noted among javelin throwers and baseball pitchers.[14] Fractures of the proximal olecranon are not uncommon in children, who are more inclined than adults to have a fracture rather than a tendino-osseous avulsion due to the triceps mechanism.

Ring and Jupiter proposed a ring theory of elbow stabilizers and mentioned the posterior column, including the triceps.[15] Most of their patients had either an olecranon fracture or no injury. Hence, they suggested that avulsion of the triceps can occur with elbow dislocation, perhaps as an alternative to an olecranon fracture.[16]

In a review by Bach et al, nearly 75% of triceps tendon ruptures reported in the literature occurred in male patients, with a male-to-female ratio of 3:1.[8]  Although the mean age at injury was approximately 26 years, patients described in case reports have had an age range of 7-72 years. The dominant and nondominant extremities appear to be injured with equal frequency, and cases of bilateral avulsion have been reported.[8, 10]

The diagnosis of triceps tendon avulsion is usually evident in patients who present with a characteristic history. The presence of a palpable gap in the posterior elbow is a more valuable symptom than loss of active elbow extension in the diagnosis of triceps tendon avulsion.[17]

Clinical features include pain and swelling of the posterior part of the elbow. A palpable depression just proximal to the olecranon may be noted on physical examination.[5, 6] These findings may be difficult to appreciate in the setting of severe pain and swelling, especially if they are present in a muscular athlete with large bulk.[4, 6] Ecchymosis may be marked several days, but not immediately, after injury.

The physician who is diagnosing an avulsion of the triceps tendon must determine whether the tear is complete or partial. To this end, careful testing of extension strength of the elbow is needed for guidance of therapeutic management. The literature suggests that a substantial loss of elbow motion and triceps power reflects a complete tear that is unlikely to improve with nonsurgical management.[18] Therefore, any nonsurgical approach to management should include close follow-up.

Variations in clinical symptoms and signs after incomplete or complete avulsions of the triceps may delay correct diagnosis. Patients with rupture of the triceps tendon may present with cubital tunnel syndrome,[19] a snapping elbow,[20] collar stud–shaped olecranon bursitis,[21] or even posterior compartment syndrome.[22] Associated injuries include radial head-neck fractures and fractures of the wrist.[5, 17]

In the treatment of apparently isolated capitellum fractures, surgeons should consider the possibility of a triceps avulsion injury. If there is a fleck sign on the lateral radiograph with suspicion of an avulsion fragment from the olecranon, the triceps mechanism should be explored as part of the extensile lateral approach in the treatment of these complex injuries.[23]

Laboratory investigations are noncontributory. However, they may help in diagnosing associated conditions, such as chronic renal failure, if such conditions are suspected.

Radiography remains the initial imaging modality of choice for evaluating a suspected triceps injury.[24] Regarding diagnostic studies, radiography should be performed in all suspected cases of triceps tendon avulsion. Of the cases reported in the literature, avulsed flecks of bone from the olecranon were demonstrated in approximately 83%.[8, 5, 6] Careful inspection of all radiographs is crucial. If necessary, oblique views of the elbow should be obtained to rule out other fractures.

Lateral radiographs of the elbow are particularly useful for diagnostic confirmation. In Tarsney's study of seven cases of triceps tendon avulsion, lateral radiographs demonstrated bone fragments behind the distal humerus and just proximal to the olecranon in six cases.[6]

Levy et al reported their experience with 16 patients who had concomitant triceps ruptures and fractures of the radial head and noted that triceps ruptures may be overlooked if the posterior aspect of the elbow is not specifically examined.[25] A single avulsed bone fleck present on the lateral radiograph of the elbow may be the only clue for correct diagnosis.

Zacharia and Roy described a clinicoradiologic classification of traumatic triceps tendon avulsion that included the following four types[26] :

• Type I - Palpable soft-tissue defect without a bony mass
• Type II - Palpable soft-tissue defect with a wafer-thin/comminuted bony fragment on radiography
• Type III - Palpable soft-tissue defect with a bony mass and a large bony fragment on radiography without extension to the articular surface
• Type IV - Olecranon fracture with < 25% of the articular surface

Ultrasonography (US) or magnetic resonance imaging (MRI) may be needed to clarify an uncertain diagnosis or to confirm clinical suspicion.[27, 28]

Nonsurgical treatment has generally been reserved for patients with partial ruptures or with ruptures of the muscle belly who demonstrated some ability to extend their arm against gravity.[8]

Avulsion of the lateral head of the triceps alone is recognized to cause no clinically significant functional impairment. This injury may be more frequent than has been recognized.[22]

Partial tendon avulsions or midsubstance muscle tears are treated nonoperatively with the arm in extension for 3-4 weeks. Gradual range-of-motion (ROM) exercises may be allowed at 3-4 weeks, as the patient's symptoms allow.[29, 30]

All complete triceps tendon avulsions must be surgically repaired to restore extension strength.[5, 31, 6]

The role of surgery in the treatment of incomplete tears is somewhat controversial. However, Farrar and Lippert stated that if full active extension can be demonstrated on physical examination a few days after injury, incomplete injuries may be considered partial and therefore may be closely observed without surgical repair.[5]

Methods of repair

For complete tears or avulsion, the accepted method of repair is reattachment of the avulsed triceps tendon to the olecranon.[32] This repair is accomplished by using drill holes with heavy nonabsorbable sutures.[5, 4, 6, 33, 34, 35]

A retrospective study comparing anchor fixation with transosseous fixation in 181 patients with 184 surgically treated acute traumatic triceps tendon avulsions found that transosseous fixation was associated with a significantly higher rerupture rate, a higher reoperation rate, and a longer time to release from medical care.[36]

If a large fragment (>50%) of the olecranon is fractured and displaced, open reduction with internal fixation (ORIF) of the olecranon by using the Arbeitsgemeinschaft für Osteosythesefragen/Association for the Study of Internal Fixation (AO/ASIF) technique of tension-band wiring is indicated. Mobilization of the triceps tendon may be required.[37] Care must be taken to avoid injuring the radial nerve with proximal mobilization.[29]

Otherwise, excision of bone fragments and repair of the triceps tendon to the articular surface are indicated. Repair of the tendon to the articular surface is necessary to minimize anterior-posterior instability of the elbow after the proximal olecranon fragment is excised.

Additional methods of triceps repair are described in the literature. These methods include use of a posterior forearm fascial flap, use of a periosteal flap from the olecranon, and use of an inverted tongue of triceps as a turned-down flap.[18, 31] These additional methods may be useful if diagnosis is delayed, if the triceps tendon is retracted, or if primary reconstruction fails.

In the instances of delayed or late reconstruction, Bennett and Mehlhoff described triceps immobilization and use of a turned-down triceps fascia flap or a fascial strip of the palmaris longus tendon or tensor fasciae latae placed through a drill hole in the olecranon.[29]

In a method of triceps tendon reconstruction with VY-plasty in the musculotendinous junction of the triceps, the required length of tendon is easily obtained by V-shaped splitting of the tendon, which does not weaken the tendon. Excellent muscle power is achieved, the blood supply is preserved because of patent continuity in the distal section, soft-tissue damage is minimal, and functional outcome is good. In addition, the method is simple and reproducible.[38]

Zacharia and Roy proposed the following treatment algorithm,[26] based on their classification of traumatic triceps tendon avulsions into four types (see Workup):

• Type I -  Transosseous suture repair/suture anchor
• Type II - Transosseous suture repair 
• Types III and IV - Tension band wiring or steel wire sutures

After surgery, the elbow is immobilized in a posterior splint in extension for anywhere from 10 days to 6 weeks, as described in the literature.[8]

According to Bennett and Mehlhoff, the elbow is generally immobilized at 30-40° of flexion for 4 weeks. A graduated ROM and strengthening program is then begun. For example, the elbow is immobilized at 30° of flexion for 4 weeks, and then 0-45° of ROM is allowed during the next 2 weeks. After this time, graduated ROM and strengthening exercises begin.[29, 30]

An extension night splint is used for the first 3 months after repair.

Complications after surgical repair have been described in the literature and include skin sloughing, infection, and repeat rupture. Pantazopoulos et al reported the development of olecranon bursitis after wire-suture fixation. The bursitis resolved after the wire was removed.[4] Overall, acceptable extension strength is restored after surgical repair.[8, 5] Many investigators have noted mild flexion contracture of 5-20° in approximately 10% of their reported cases.[25, 6]

A systematic review of 19 studies (N = 560) determined that in 565 instances of surgically repaired distal triceps tendon rupture, the overall incidence of postoperative complications was 14.9%.[39] ​ Common complications included ulnar neuropathy, infection, and pain. When different repair techniques were compared, the incidence of complications was found to be 29.2% for the direct repair technique, 15.2% for the transosseous technique (transosseous suture), and 7.7% for the suture anchor technique.  

The patient's return to contact sports should be restricted until maximal motion and extension strength are achieved. These outcomes are usually attained after 6 months. Patients should perform active resistive strengthening to achieve equal strength in the triceps for 3-6 months after surgery.[29]