Distal Biceps and Triceps Tendon Injuries

Distal biceps and triceps tendon injuries are uncommon.  Rupture is usually caused by a forced eccentric contraction of the muscle.  Conservative management has been shown to result in functional deficit with operative management fast becoming the mainstay of treatment. This is especially true for younger and more active patients and those with manual occupations.

Distal Biceps Tendon Injuries

Introduction

Distal biceps tendon rupture was first reported by Starks in 1843. 

It is an uncommon injury with a reported incidence of 1.2 per 100,000 and accounts for only 3% of all biceps injuries.  

These injuries are most commonly seen in middle aged men.

Anatomy

The biceps-brachii muscle consists of 2 heads (long and short) and spans both the shoulder and elbow joints.

Origin: Coracoid process (short head) and supra-glenoid tubercle (long head)

Insertion: Radial tuberosity (common terminal tendon) and deep fascia forearm (lacertus fibrosus)

Innervation: Musculocutaneous nerve

The distal biceps tendon rotates through 90 degrees attaching to the ulnar most aspect of the radial tuberosity forming a large footprint, 21mm in length.   Many of the surgical techniques have attempted to recreate this footprint. 

The main action of biceps is forearm supination.  It also aids in flexion, being most effective in a supinated forearm position.  Its role in flexion is minimal in full pronation.

Risk Factors for rupture

• Tendon hypo-vascularity and degeneration
• Mechanical impingement during prono-supination
• Smoking (7.5 times greater risk)
• Steroid use

 Clinical Presentation and Diagnosis

Rupture most commonly occurs during forced extension of a flexed elbow which results in eccentric contraction of the biceps.  Patients will often describe a sudden pain or “pop” on the anterior aspect of the elbow.  This is usually associated with antecubital fossa and forearm bruising.  Patients may also describe weakness and may have continued pain, especially in partial tears. 

On inspection a “reverse pop-eye” sign may be seen, caused by retraction of the biceps muscle belly proximally.  This may not always be apparent in case of a partial tear or if the lacertus fibrosus is still intact.  

The “hook test” is the most sensitive and specific test (100% for each) and involves the examiner placing an index finger round the tendon from the lateral side during active flexion and supination of the elbow. The finger will usually hook underneath an in tact distal biceps. A common error is to mistake the lacertus fibrosus with distal biceps leading to delayed diagnosis.

The “bicipital aponeurosis flex test” can be undertaken to assess the integrity of the lacertus fibrosus.  It is carried out by asking the patient to actively flex a supinated forearm whilst making a fist.  At 75 degrees of flexion, the edge of the lacertus fibrosus can be felt medially in the cubital fossa (Sensitivity 100%, Specificity 90%).

Imaging

Plain radiographs are undertaken routinely and may rarely show a small avulsed fragment from the radial tuberosity. 

Diagnosis is usually made clinically but ultrasound and MRI can be helpful in assessing the degree of tendon retraction and whether the injury is complete or partial.  MRI is also useful in identifying other pathologies around the elbow.

Non-operative Treatment 

Conservative management is indicated in elderly, low demand patients or those with multiple comorbidities. 

This consists of analgesia and gentle progressive mobilisation

Outcome:

Up to 30% reduction in flexion strength

Up to 40 - 50% reduction in supination strength

Up to 79% reduction in endurance

Surgical Treatment

Surgical repair is the management choice for most.  It consists of an anatomical repair to the radial tuberosity.  This can be undertaken using either a single (Dobbie) or dual incision (Boyd and Anderson) technique.  Fixation types include anchor fixation, intraosseous interference screw or cortical button utilising a bone tunnel.

Complications:

• Lateral antebrachial cutaneous nerve injury (most common)
• Heterotopic ossification
• Re-rupture (1.6 – 1.8%)
• Synostosis
• CRPS (chronic regional pain syndrome)
• Elongation of the biceps tendon
• Radial artery and recurrent radial artery spasm and injury

The complication rate has been reported to be as high as 33%.

Outcomes:

Operative management has shown to result in better functional outcome compared to conservative management.

There have been 2 systematic reviews to date for surgical repair of distal biceps injuries.  Watson et al reviewed 22 studies (494 patients) and found no difference in complication rates between either single or double incision techniques.  Bone tunnel with cortical button fixation type was shown to have a lower complication rate than suture anchors and interosseous screw techniques.  Kodde et al reviewed 40 studies (1074 patients) and found that the complication rate was lower in the double incision technique compared to single incision.  They acknowledged that the lower complication rate may be due to the higher number of bone tunnel fixation types in the dual incision group rather than the approach itself.

Partial Rupture

Partial rupture is less common than complete rupture and the hook test is often negative.

The main presenting complaint is pain over biceps insertion with resultant weakness. MRI scanning may help in the diagnosis. 

There is no agreed consensus in the management if the injuries. 

Conservative management may result in a good outcome but if there is persistent pain at 6 weeks then surgical management should be considered. This involves completion of the tear, and anatomic repair to the prepared footprint.

Chronic Rupture

Primary repair should be carried out within the first few weeks following injury. 

In those who present late, primary repair may be still be possible but tendon retraction and fibrosis may prove problematic. 

A more extensile approach may be required.  Operative options include direct sturing of the biceps tendon to brachialis, reconstruction with auto/allograft (semitendinosus, fascia lata, lacertus fibrosus, tendo-Achilles), or reconstruction with synthetic allograft.

Distal Triceps Tendon Injuries

Introduction

Rupture of the triceps tendon is a rare injury.  It was first reported by Partridge in 1868.  These injuries are more common in men and between the ages of 30 to 50.

Anatomy

The triceps brachii muscle has three heads and is the only muscle in the posterior compartment of the arm. 

Origin: Infra-glenoid tubercle (long head), posterior surface of the humerus on superior border of the radial groove (short head), posterior surface of the distal humerus (medial head).

Insertion: Olecranon (common terminal tendon)

Innervation: Radial nerve

The primary function is to extend the elbow through the ulno-humeral joint but also contributes to adduction and extension of the arm through its long head.

Risk Factors for rupture

• Previous elbow surgery through posterior approach
•  Degenerative tendon
•  Rheumatoid arthritis
•  Chronic renal failure
•  Olecranon bursitis

Clinical Presentation and Diagnosis 

Acute rupture is caused by a sudden eccentric loading of the triceps, usually as a result of a fall onto an outstretched hand.    Direct trauma to a flexed elbow may also cause rupture.  The tendon ruptures most commonly at its insertion on the olecranon.  Patients tend to experience an acute pain on the posterior aspect of the elbow with weakness in elbow extension.  Patients are often still able to actively extend the elbow due the action of anconeus. 

The “squeeze test” is performed similarly to the Thompson test for tendo-Achilles injury.  With the patient in the prone position and the upper arm supported, allowing the forearm to hang free, the triceps is squeezed.  With complete triceps tendon rupture there is no extension of the elbow against gravity.

With a positive “triceps fall down test” the patient is unable to keep the elbow in extension against gravity with the shoulder abducted to 90 degrees.  

 Imaging 

Plain radiographs may show the pathognomonic “flake sign” representing a small avulsed fragment from the olecranon.  Other fractures may be identified; in particular that of the radial head.

In cases where the diagnosis is in doubt, ultrasound or MRI may be useful.

 Non-operative Treatment

Conservative management will result in an extension strength deficit of the elbow. This may be acceptable in elderly, low demand patients or those with high operative risk.  Treatment options include gentle mobilisation to immobilisation in an extension splint for up to 4 weeks. 

 Surgical Treatment 

Although partial tendon ruptures are more common than complete ruptures it is generally accepted that repair is required for any rupture at the tendo-osseous junction.  The repair is commonly carried out using a Bunnel or Krakov suture technique with a heavy non-absorbable suture material.   The tendon is then re-attached to the olecranon via drill holes.  A more anatomical ‘double row’ technique has been described which allows reconstruction of the footprint using suture anchors.  This technique has been shown to have higher load to failure than the traditional trans-osseous technique but studies looking at functional outcome demonstrated good results for both techniques. 

Chronic Rupture

Techniques used for reconstruction of chronic ruptures include anconeus slide or supplementation with palmaris longus, Achilles or hamstring grafts. 

Recently, reconstruction with LARS ligament has been described.  Outcomes for reconstruction are comparable to those of primary repair.