Distal Biceps Avulsion

Topic updated on 08/22/16 9:41am
  • Injury may either be a
    • complete distal biceps avulsion
    • partial distal biceps avulsion
      • partial distal biceps tendon tears occur primarily on the radial side of the tuberosity footprint. q
    • intersubstance muscles transection
      • seen when rope wrapped around arm (tug-of-war)
  • Epidemiology
    • Incidence
      • rare
      • distal biceps tendon rupture represents about 10% of biceps ruptures.
    • demographics
      • ruptures tend to occur in the dominant elbow (86%) of men (93%) in their 40s.
    •  risk factors
      • hypovascularity of tendon
      • intrinsic degeneration of tendon
      • mechanical impingement in the space available for the biceps tendon
      • 7.5 times greater risk of distal biceps tendon ruptures in persons who smoke
  • Pathophysiology
    • mechanism
      • excessive eccentric tension as the arm is forced from a flexed to an extended position 
  • Associated conditions
    • rarely it can lead to symptoms of median nerve compression
  • Biceps tendon inserts onto the radial tuberosity. 
  • Distal biceps tendon possesses two distinct insertions
    • the short head attaches distally on the radial tuberosity
    • the long head attaches proximally on the radial tuberosity
  • Lacertus fibrosus
    • distal to the elbow crease, the tendon gives off, from its medial side, the lacertus fibrosus (bicipital aponeurosis or biceps fascia)
    • originates from the distal short head of the biceps tendon.
    • lacertus passes obliquely across the cubital fossa, running distally and medially, helping to protect the underlying brachial artery and median nerve
    • it is continuous with the deep fascia of the flexor tendon origin.
    • may be mistaken for an intact distal biceps tendon on clincial exam.
  • History
    • patient often experiences a painful “pop” as the elbow is eccentrically loaded from flexion to extension.
  • Symptoms
    • weakness and pain, primarily in supination, are hallmarks of the injury.
  •  Physical exam
    • inspection and palpation
      • varying degree of proximal retraction of the muscle belly.
        • “reverse Popeye sign”
      • change in contour of the muscle, proximally.
      • medial ecchymosis
      • a palpable defect is often appreciated.
    • motor exam
      • loss of supination and flexion strength 
        • Loss of more supination than flexion, up to 50% 
    • provocative tests
      • Hook test    
        • performed by asking the patient to actively flex the elbow to 90° and to fully supinate the forearm
        • examiner then uses index finger to hook the lateral edge of the biceps tendon.
          • with an intact or even partially intact biceps tendon, the finger can be inserted 1 cm beneath the tendon
        • continuity of the tendon may suggest a partial tear.
          • the readily palpable lacertus fibrosis may remain intact.
          • the underlying brachialis tendon may also be mistaken for the biceps
        • sensitivity and specificity
          • 100%
      • Biceps squeeze test
        • elbow held in 60-80° of flexion with the forearm slightly pronated.
        • one hand stabilizes the elbow while the other hand squeeze across the distal biceps muscle belly.
        • a positive test is failure to observe supination of the patient’s forearm or wrist.
        • Sensitivity
          • 96%
      • challenge is to distinguish between complete tear and partial tear.
        • biceps tendon is absent in complete rupture and palpable in partial rupture (otherwise they have a very similar clinical picture)
  • Radiographs
    • usually normal
    • occasionally show a small fleck or avulsion of bone from the radial tuberosity
  • MRI
    • is important to distinguish between q
      • complete tear vs. partial tear 
      • muscle substance vs. tendon tear
      • degree of retraction
  • Nonoperative
    • supportive treatment followed by physical therapy
      • indications
        • older, low-demand or sedentary patients who are willing to sacrifice function 
        • if the lacertus fibrosis is intact, the functional deficits of biceps rupture may be minimized in a low-demand patient.
      • outcomes
        • will lose 40-50% supination
        • will lose ~30% flexion
        • will lose 15% grip strength
  • Operative
    • surgical repair of tendon to tuberosity 
      • indications
        • young healthy patients who do not want to sacrifice function  
        • partial tears that do not respond to nonoperative management
      • timing
        • surgical treatment should occur within a few weeks from the date of injury
          • further delay may preclude a straightforward, primary repair.
          • a more extensile approach may be required in a chronic rupture to retrieve the retracted and scarred distal biceps tendon.
Surgical Techniques
  • Anterior Single Incision Technique
    • technique
      • limited antecubital fossa incision
      • interval between the brachioradialis and pronator teres
      • radial (lateral) retraction of the brachioradialis and medial retraction of the pronator teres
      • lateral antebrachial cutaneous (LABC) nerve is identified as it exits between the biceps and the brachialis at the antecubital fossa.
      • protect posterior interosseous nerve (PIN) by limiting forceful lateral retraction and maintaining supination
    • complications
      • injury to the lateral antebrachial cutaneous (LABC) nerve is most common 
      • injury to radial nerve is most severe
        • risk has decreased with new tendon fixation techniques that require less dissection in the antecubital fossa
      • synostosis and resulting loss of pronation/supination
        • avoid exposing periosteum of ulna
        • avoid dissection between the radius and ulna
      • heterotopic ossification
    • postoperative
      • immobilize in 110° of flexion and moderate supination
  • Dual Incision Technique
    • recommended by most
    • technique
      • uses smaller anterior incision over the antecubital fossa and a second posterolateral elbow incision
        • posterior interval is between ECU and EDC  
        • avoid exposing ulna
          • do NOT use interval between ECU/anconeus (Kocher's interval) or anconeus and ulna  
      • anterior dissection is same as single incision described above
      • after the biceps is identified, the radial tuberosity is palpated, and a blunt, curved hemostat is placed in the interosseous space along the medial border of the tuberosity and palpated on the dorsal proximal forearm.
      • hemostat pierces anconeus and tents the skin indicating where the posterolateral incision should be made
    • complications
      • lateral antebrachial cutaneous nerve injury is most common  
      • by using two incisions, goal is to avoid deep dissection in the antecubital fossa and minimize risk to the radial nerve
      • synostosis
      • heterotopic ossification
  • Distal Biceps Fixation Techniques
    • bone tunnel
      • 2-incision approach
      • tuberosity is exposed and a guide pin drilled through the center of the tuberosity
      • an acorn reamer is used to ream through the anterior cortex to recreate a slot of varying depth
      • two or three 2-mm diameter holes are drilled 1 cm apart through the lateral, far side of the radius
      • no. 2 sutures sown to the distal tendon are passed and tied across the bone bridge.
    • suture anchors
      • single-incision approach
      • radial tuberosity is debrided to prepare for bone-to-tendon healing
      • two suture anchors are inserted into the biceps tuberosity, one distal and one proximal.
      • the distal anchor is tied first to bring the tendon out to length.
      • next, the sutures of the proximal anchor are tied. This repair sequence maximizes tendon-to-bone contact and surface area.
    • intraosseous screw fixation
      • single-incision approach
      • similar to the bone tunnel technique, except the No. 2 suture (whip-stitched through the tendon) is passed through a bioabsorbable tenodesis screw.                     
    • suspensory cortical button
      • single-incision approach
      • the tendon end is whip-stitched with the suture ends placed into two central holes of the button.
      • similar to the bone tunnel technique, an acorn reamer is used to ream through the anterior cortex after exposing the tuberosity.
      • a smaller hole is then drilled through the far cortex to allow the button to be passed across the far cortex.
      • the button is then flipped to lie on the far cortex, and the suture ends are tensioned to bring the tendon into the tunnel.
  • Lateral antebrachial cutaneous nerve injury
  • Radial nerve injury
  • Heterotopic ossification
  • Synostosis


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Qbank (8 Questions)

(OBQ12.204) A 44-year-old left-hand dominant carpenter has the onset of left elbow pain after trying to stop a heavy object from falling two days ago. Figure A shows a clinical image of the patient upon presentation. Physical exam shows full strength with wrist flexion, wrist extension and pronation, but notable weakness with supination of the forearm. Sensory exam shows no deficits in the forearm or hand. There is a negative milking maneuver test, and abnormal hook test in the region of the elbow. Radiographs are shown in Figure B. What is the next most appropriate step in management? Topic Review Topic
FIGURES: A   B        

1. Sling use as needed for comfort and progressive physical therapy
2. Allograft reconstruction of the distal biceps tendon
3. Ulnar collateral ligament reconstruction
4. Distal biceps tendon avulsion repair
5. Brachioradialis and ECRB avulsion repair

(OBQ11.170) A 28-year-old male sustains a distal biceps rupture while lifting a heavy table and elects to undergo surgical repair using a two-incision technique. What is the most likely neurologic deficit to occur as a complication of this surgical approach? Topic Review Topic

1. Intrinsic hand weakness
2. Numbness of the volar radial three and a half digits
3. Wrist extension weakness
4. Numbness to lateral aspect of volar forearm
5. Inability to flex thumb and index interphalangeal joints

(OBQ09.96) A 40-year-old male was moving his furniture several days ago when he developed anterior forearm pain. On physical exam he is tender just distal to the antecubital fossa. He has decreased strength on supination and elbow flexion when compared to the contralateral side. His MRI is shown in Figures A and B. His injury typically occurs in what portion of the tendon’s distal insertion? Topic Review Topic
FIGURES: A   B        

1. Proximal
2. Distal
3. Central
4. Radial
5. Ulnar

(OBQ08.75) A patient sustains a distal biceps brachii tendon rupture. If treated non-operatively, the greatest loss of strength would be seen with which activity? Topic Review Topic

1. Forearm supination
2. Forearm pronation
3. Elbow flexion
4. Shoulder forward flexion
5. Shoulder internal rotation

(OBQ08.83) A 35-year-old carpenter has pain in the antecubital fossa that is worse with turning a screwdriver. He has undergone non-operative treatment for 6 months without relief. On physical examination his hook test is normal and there is pain and weakness with resisted supination. Radiographs are shown in Figures A-C. A MRI of the right elbow is shown in Figure D. The next most appropriate treatment is? Topic Review Topic
FIGURES: A   B   C   D    

1. Exploration of the radial tunnel
2. Superficial radial neurectomy
3. Detachment and repair of the biceps tendon
4. Transfer of the biceps to the brachialis
5. EMG with nerve conduction study

(OBQ08.128) What nerve is injured most commonly during the superficial dissection when repairing a distal biceps rupture through a single incision anterior approach? Topic Review Topic

1. Medial antebrachial cutaneous nerve
2. Lateral antebrachial cutaneous nerve
3. Superficial radial nerve
4. Ulnar nerve
5. Posterior interosseous nerve

(OBQ04.151) A 42-year-old male has a suspected distal biceps rupture with a tendon that can be palpated but is painful during the hook test examination. Which of the following is the most appropriate next step? Topic Review Topic

1. Operative exploration of distal biceps tendon
2. Immobilization for three weeks followed by repeat physical examination
3. Early physical therapy with emphasis on ROM and strengthening
4. CT scan
5. MRI scan

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