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  • summary
    • Distal Biceps Avulsions are injuries to the biceps tendon at the radial tuberosity insertion that generally occurs due to a sudden excessive eccentric contraction of the biceps brachii.
    • Diagnosis can be made clinically in the setting of complete tears with a hook test. MRI studies can be used to discern between a complete tear and a partial tear. 
    • Treatment can be nonoperative or operative depending on patient age, patient activity demands, chronicity of tear, and degree of tear. 
  • 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.
    • Anatomic location
      • complete distal biceps avulsion
      • partial distal biceps avulsion
        • partial distal biceps tendon tears occur primarily on the radial side of the tuberosity footprint.
      • intersubstance muscle transection
        • seen when rope wrapped around arm (tug-of-war)
    • Risk factors
      • anabolic steroids
      • smoking has 7.5x greater risk than nonsmokers
      • hypovascularity
      • intrinsic degeneration
      • mechanical impingement in the space available for the biceps tendon
  • Etiology
    • Pathophysiology
        • excessive eccentric tension as the arm is forced from a flexed to an extended position "flexed elbow unacceptably challenged"
        • vascular watershed
        • mechanical attrition (abrasion during pronosupination)
    • Associated conditions
      • rarely it can lead to symptoms of median nerve compression
  • Anatomy
    • Biceps tendon inserts onto the radial tuberosity.
    • Contents of antecubital fossa (medial to lateral)
      • median nerve (most medial structure), brachial artery, biceps tendon, radial nerve (most lateral structure)
      • radial recurrent vessels lie superficial to biceps tendon
    • Distal biceps tendon possesses two distinct insertions
      • short head attaches distally on radial tuberosity (thin sliver)
        • origin is coracoid processs
        • is a better flexor
      • long head attaches proximally on radial tuberosity (oval footprint)
        • origin is the superior lip of the glenoid and glenoid labrum
        • is a better supinator as attachment is furthest from axis of rotation (attaches to apex of radial tuberosity)
        • independent function to prevent anterior, inferior and superior translation of humeral head against proximal pull of short head of biceps
    • 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, envelopes flexor muscle bellies
      • may be mistaken for an intact distal biceps tendon on clincial exam
  • Presentation
    • 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 more supination than flexion strength
          • loss of 50% sustained supination strength
          • loss of 40% supination strength
          • loss of 30% flexion strength
      • 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 / partially torn tendon, finger can be inserted 1 cm beneath the tendon
          • false positive
            • partial tear
            • intact lacertus fibrosis
            • underlying brachialis tendon
          • sensitivity and specificity 100%
        • Ruland biceps squeeze test (akin to the Thompson/Simmonds test for Achilles rupture)
          • elbow held in 60-80° of flexion with the forearm slightly pronated.
          • one hand stabilizes the elbow while the other hand squeezes 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)
  • Evaluation
    • Radiographs
      • usually normal
      • occasionally show a small fleck or avulsion of bone from the radial tuberosity
    • MRI
      • positioning in elbow flexion, shoulder abduction, forearm supination increases sensitivity
      • is important to distinguish between
        • complete tear vs. partial tear
        • muscle substance vs. tendon tear
        • degree of retraction
  • Treatment
    • 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 50% sustained supination strength
          • will lose 40% supination strength
          • will lose 30% flexion strength
          • 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
          • subacute/chronic ruptures may be treated successfully with direct repair (without allograft)
            • may need to hyperflex elbow to achieve fixation
            • hyperflexion does NOT lead to loss of elbow ROM or flexion contracture
        • 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.
  • Techniques
    • Anterior Single-Incision Technique
      • single incision technique was developed to reduce the incidence of HO and synostosis seen with the double 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 nerve (LABCN) is identified as it exits between the biceps and brachialis at antecubital fossa.
        • recurrent radial vessels encountered and either coagulated or carefully dissected and retracted
        • protect PIN by limiting forceful lateral retraction and maintaining supination
      • complications
        • injury to the LABCN is most common
          • more LABCN injury than 2-incision approach
        • radial nerve or PIN injury 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
          • less common than with 2 incision technique
      • postoperative
        • immobilize in 110° of flexion and moderate supination
    • Dual Incision Technique
      • developed to avoid injury to radial nerve/PIN
      • 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
        • LABCN injury is most common
        • synostosis and heterotopic ossification more common with 2 incision than single incision
    • Distal Biceps Fixation Techniques
      • comparison
        • tolerances
          • elbow at 90°, no load, distal biceps sustains 50N
          • elbow at 90°, with 1kg load, distal biceps sustains 112N
          • force to rupture = 200N
          • repair needs to be able to withstand 50N
        • suture button (400N) > suture anchor (380N) > bone tunnel (310N) > interference screw (230N)
        • combination technique (suture button + interference screw) stronger than single technique
      • bone tunnel
        • 2-incision approach
        • tuberosity is exposed and a guide pin drilled through the center of the tuberosity
        • acorn reamer is used to ream through 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
        • 2 suture anchors 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
        • tendon end is whip-stitched with the suture ends placed into two central holes of the button.
        • similar to bone tunnel technique, an acorn reamer is used to ream through the anterior cortex after exposing tuberosity.
        • a smaller hole is then drilled through the far cortex to allow the button to be passed across the far cortex.
        • button is flipped to lie on far cortex, and suture ends are tensioned (tension slide) to bring tendon into tunnel
  • Complications
    • LABCN injury
      • most common complication overall (9% incidence)
      • because of overaggressive retraction
      • more common with single incision technique
      • usually resolved in 3-6mth
    • PIN injury
      • more common in single incision than 2 incision technique
      • most commonly injured motor nerve (1-2% incidence)
      • usually resolve in 3-6mth
    • Superficial radial nerve injury
      • 2nd most common cutaneous nerve injured (2-3%)
    • Heterotopic ossification
      • if interosseous membrane and ulnar periosteum disrupted
      • a risk of the 2 incision technique
    • Synostosis
    • Proximal radius fracture
      • from large tunnels or those proximal to the radial tuberosity 
    • Suture rupture (if bone tunnel method used)
Technique Guides (2)
Flashcards (4)
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Questions (27)
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(OBQ19.104) A 45-year-old man presents with right upper extremity weakness following an intense workout session. He has weakness most pronounced with attempted supination and the findings depicted in Figure A on clinical examination. The surgeon proceeds with operative repair of his injury using a single-incision technique. How would the most common complication of this surgical treatment manifest?

QID: 214006

Symptomatic heterotopic ossification



Weakness in wrist extension



Decreased sensation to the volar radial aspect of the forearm



Decreased sensation to the dorsum of the hand



Weakness in finger adduction



L 4 A

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(SBQ17SE.23) A 47-year-old former professional wrestler is helping his friend move some furniture. A large sofa slips from the patient's grip, which causes his elbow to extend. He feels a pop and develops ecchymosis about his antecubital fossa. He discusses his care with a hand surgeon who recommends surgical repair, but the patient is reluctant. Conservative management of this pathology has been shown to result in all of the following EXCEPT?

QID: 211358

Lateral antebrachial neuritis



Loss of supination strength



Loss of supination endurance



Loss of flexion strength



Delayed return to activities



L 4 A

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(SBQ17SE.25) A 42-year-old man is performing his final deadlift at the annual CrossFit games when he suddenly experiences severe pain in his right arm and is unable to continue. Physical examination is significant for medial brachial ecchymosis, swelling and tenderness over the antecubital fossa, and significantly diminished supination strength. Radiographs are unremarkable and an MRI is shown in Figure A. Given his age and activity level, he is taken for primary surgical repair utilizing a single-incision technique with combined cortical button and interference screw fixation. When the patient returns to clinic, he is found to have experienced the most common neurologic complication associated with this procedure. What is the course of the affected nerve?

QID: 211380

Branches distal to the elbow, passing between two heads of pronator teres, running along volar aspect of the flexor digitorum profundus



Dives through the supinator, coursing around the radial neck within the deep compartment of the forearm



Pierces the fascia of the biceps brachii and lays lateral to biceps tendon, deep to the cephalic vein, until emerging and running superficially along the brachioradialis



Runs deep to the brachioradialis and lateral to the radial artery, piercing the fascia of the brachioradialis and becoming superficial within the distal forearm



Runs with brachial artery where it enters the forearm between the pronator teres and biceps tendon, traveling between the flexor digitorum superficialis and profundus



L 1 A

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(SBQ16SM.20) A 44-year-old male sustains the injury shown in Figures A and B. Which of the following statements is true in regards to the treatment for the injury depicted?

QID: 211326

Non-surgical management results in improved strength and range of motion



The most common complication related to surgical management is an injury to the terminal branch of the musculocutaneous nerve



Surgical fixation with bone tunnels offers the weakest repair



Surgical fixation with a cortical button offers the strongest repair



Synostosis is the most common complication following a single-incision surgical approach



L 3 B

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(OBQ12.204) A 44-year-old left-hand dominant carpenter experienced immediate 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 a positive hook test. Radiographs are shown in Figure B. What is the next most appropriate step in management?

QID: 4564

Sling use as needed for comfort and progressive physical therapy



Allograft reconstruction of the distal biceps tendon



Ulnar collateral ligament reconstruction



Distal biceps tendon avulsion repair



Brachioradialis and ECRB avulsion repair



L 1 A

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(OBQ11.213) A patient presents to your office for evaluation of arm pain. Upon evaluation, a diagnosis of rupture of the long head of the biceps tendon is made. Which of the following photographs would best corroborate this diagnosis?

QID: 3636
















L 1 C

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(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?

QID: 3593

Intrinsic hand weakness



Numbness of the volar radial three and a half digits



Wrist extension weakness



Numbness to lateral aspect of volar forearm



Inability to flex thumb and index interphalangeal joints



L 3 A

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(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?

QID: 2909
















L 1 D

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

QID: 514

Medial antebrachial cutaneous nerve



Lateral antebrachial cutaneous nerve



Superficial radial nerve



Ulnar nerve



Posterior interosseous nerve



L 2 B

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(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?

QID: 469

Exploration of the radial tunnel



Superficial radial neurectomy



Detachment and repair of the biceps tendon



Transfer of the biceps to the brachialis



EMG with nerve conduction study



L 1 C

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(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?

QID: 461

Forearm supination



Forearm pronation



Elbow flexion



Shoulder forward flexion



Shoulder internal rotation



L 1 C

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(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?

QID: 1256

Operative exploration of distal biceps tendon



Immobilization for three weeks followed by repeat physical examination



Early physical therapy with emphasis on ROM and strengthening



CT scan



MRI scan



L 2 D

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Evidence (35)
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