Ruptures of the distal biceps brachii tendon are uncommon, constituting only 2% to 10% of all biceps tendon injuries.1 The incidence of this injury is less than 2:100,000 in the general population.2 Distal tendon ruptures occur most commonly in the dominant upper extremity of males between the ages of 40 and 60 years.3 Ruptures typically occur at the tendon insertion to the radial tuberosity in an area of preexisting tendon damage when the muscle undergoes a rapid eccentric contraction with the elbow flexed to approximately 90 degrees.3 Other risk factors for tendon failure include hypovascularity of the tendon (commonly observed in smokers) and mechanical impingement of the tendon in the cubital fossa.2
Evaluation findings typically include a traumatic mechanism of injury, palpable deformity in the cubital fossa, and a loss of elbow flexion and forearm supination strength.4 The deformity observed with a distal rupture is sometimes called a “reverse Popeye biceps,” which is in reference to a long head of the biceps tendon rupture from the supraglenoid tuberosity resulting in a deformity commonly called a “Popeye biceps.”5 Loss of strength is more definitive in supination, which may demonstrate a 40% to 50% loss compared to elbow flexion, which typically demonstrates a 30% loss of strength.4
A 21-year-old male cadet cheerleader complained of pain over his anterior elbow after catching a flyer while practicing stunts. The patient reported that the traumatic impact was primarily absorbed by his left arm, which was flexed at a 90-degree angle at the time of the injury. The patient reported immediately feeling a “pop” and sharp pain in his cubital fossa. The patient also complained of an inability to actively flex his elbow following the injury. Initial evaluation by an athletic trainer identified an obvious deformity just proximal to the cubital fossa. Assessment of range of motion, strength testing, and special tests was deferred due to this obvious deformity. Neurological and circulatory assessments were grossly within normal limits. The patient was removed from all activity, placed into a sling, and referred to the team physician.
Physician assessment revealed the same findings as the athletic trainer's evaluation. The differential diagnosis for this patient included elbow dislocation, radial head or tuberosity fracture, and distal biceps tendon rupture. A magnetic resonance imaging series was ordered, which confirmed the diagnosis of a distal biceps tendon rupture (Figure 1). The patient was scheduled for surgical repair 10 days following the injury. Surgery consisted of an anterior approach, in which the torn tendon was reattached to the radial tuberosity by bone anchors. Following the surgical repair, the patient was immobilized in a sling for 5 days before beginning passive range of motion exercises in elbow and wrist flexion and extension. Five days following the surgery, the sling was removed and the patient was allowed to embark on a more aggressive rehabilitation plan. Rehabilitation progressed during week 2 following surgery to include active-assistive range of motion exercises for the elbow, forearm, and wrist without limitation of range of motion. The patient was also instructed not to lift more than 2 pounds with the involved upper extremity during rehabilitation or activities of daily living at this time.
T2-weighted, sagittal view magnetic resonance imaging scan demonstrating the patient's initial distal biceps tendon rupture.
Following several weeks of rehabilitation, the patient suffered a second mechanism of injury when he tripped and fell with his left arm outstretched. During the evaluation, the patient complained of hearing a “pop” associated with the mechanism of injury. On visual inspection, an obvious deformity was observed. Palpation revealed the absence of the distal biceps tendon and range of motion assessment demonstrated an inability to actively flex the elbow. Neurologic and circulatory assessments were within normal limits. Next, the athletic trainer referred the patient to the on-call physician. This physician evaluated the patient and found identical signs and symptoms as the athletic trainer. Additionally, the physician performed a hook test, which was positive for a ruptured distal biceps tendon. The physician then ordered a second round of plain radiographs and a magnetic resonance imaging series. Diagnostic imaging revealed a ruptured distal biceps brachii tendon, demonstrating a failed surgical repair (Figure 2). A surgical revision was performed involving an endobutton fixation technique.
T2-weighted, sagittal view magnetic resonance imaging scan demonstrating the failed repair of the distal biceps tendon following the patient's second injury.
A more conservative rehabilitation plan was implemented following the second surgical repair, including the use of a range of motion brace locked at 90 degrees of elbow flexion for 4 weeks. Range of motion limitations were then reduced to 45 degrees from full elbow extension during weeks 5 to 8 following surgery and progressed to full elbow extension 12 weeks following surgery. Resistive isometric strengthening was initiated 8 weeks following repair. Active range of motion exercises in elbow flexion and forearm supination were initiated 10 weeks after surgery. Isotonic resistance exercises focusing on elbow flexion, elbow extension, forearm supination, forearm pronation, wrist extension, and wrist flexion were added using a low weight with high repetition beginning 12 weeks after the second surgical repair and progressing in intensity for a period of 8 weeks. The patient was cleared to initiate unrestricted strength training 6 months after the second surgical repair.
The hook test is a valuable tool during the clinical examination of a patient with a suspected distal biceps tendon rupture. This test is performed by having the patient actively supinate the forearm with the shoulder abducted and the elbow flexed to 90 degrees.5 The clinician then attempts to hook his or her index finger under the distal biceps tendon using a lateral approach (Figure 3).5 In the presence of a distal biceps tendon rupture, the clinician will be unable to identify the cord-like tendon in the cubital fossa. In a study of 45 patients with complete (n = 33) and partial (n = 12) distal biceps tendon ruptures, both the sensitivity and specificity of the hook test were found to be 1.00.5 In the same study, the diagnostic accuracy of the hook test proved superior to magnetic resonance imaging, with a sensitivity of 0.92 and specificity of 0.85.5
The Hook test performed to diagnose a distal biceps tendon rupture.
Another potentially useful diagnostic tool is the biceps crease interval. This measurement assesses the distance between the antecubital crease of the elbow and the cusp of the distal descent of the biceps muscle to measure proximal retraction of the tendon.6 The normal biceps crease interval in males with no history of a distal biceps tendon injury is 4.8 cm and the ratio when comparing bilaterally is 1:0.6 In the presence of a distal biceps tendon rupture, these measures increase to 6 cm or a ratio of greater than 1:2.6 The biceps crease interval has a sensitivity of 0.96 and diagnostic accuracy of 93% for identifying complete distal biceps tendon ruptures.6
Surgical repair of the distal biceps tendon is performed in patients requiring adequate strength in elbow flexion and supination to complete functional sport, work, and activities of daily living that cannot be obtained through non-surgical treatment.2 Although small measurable deficits in power, endurance, and range of motion are noted following surgical repair, most patients are able to regain functional range of motion and strength, allowing a return to activities performed before the injury.7,8
Two basic surgical approaches are used in repairing the distal biceps tendon, one involving only an anterior incision and the second, more common approach, requiring both anterior and lateral incisions.3,7 The two-incision technique is known as the Boyd–Anderson procedure.9,10 The anterior only approach results in less risk of heterotopic bone formation, but carries a greater risk of posterior interosseous nerve involvement. The single incision approach may also incorporate reattachment of the torn tendon to the radial tuberosity using an endobutton.11 The use of endobutton fixation provides patients with minimal morbidity, better cosmetic results, and outstanding functional outcomes as measured by the Disabilities of Arm, Shoulder and Hand (DASH) outcome measure and Mayo Elbow Score.11 This surgical repair technique has also demonstrated excellent results in returning athletes to sport participation without complications following surgery.11
A cadaveric study examining failure loads following typical surgical repair techniques found that the endobutton technique required the greatest load to cause tissue failure.1 Conversely, the anterior and lateral approach diminishes the risk of radial nerve injury but increases the risk of heterotopic bone formation, which results in a loss of forearm range of motion.7 With respect to functional outcomes, both surgical techniques result in positive patient outcomes, with the only statistically significant difference being a 10% strength advantage in elbow flexion in patients undergoing the Boyd–Anderson procedure.12
Complications following surgery occur in one-third of patients.2,9 The most common complication is lateral antebrachial cutaneous nerve entrapment, occurring in one-fourth of all patients.2 Less frequent complications include radial sensory nerve paresthesia, posterior interosseous nerve injury, symptomatic heterotopic ossification, superficial infection, and complex regional pain syndrome.2,9 Most of these complications are minor sensory nerve injuries that resolve over time.
Complications are most commonly identified in patients who undergo surgical intervention more than 21 to 28 days after injury.2,7,9 However, surgical revisions due to re-rupture of distal biceps tendon repairs are rare, occurring in only 1% to 2% of cases.2,7,9
Implications for Clinical Practice
The current case demonstrates the need for the proper diagnosis of distal biceps tendon injury. The hook test and biceps crease interval assessment both prove to be valuable clinical assessment tools in diagnosing complete biceps tendon rupture. These assessment tools may also prove valuable in differentiating partial versus complete tears that necessitate further diagnostic imaging or surgical intervention. Repair of a distal biceps tendon rupture should occur within the first 21 days after injury for the best patient outcomes.
The rehabilitation program following surgery should emphasize protected range of motion during the initial 8 weeks of rehabilitation.3 Initial rehabilitation should focus on restoring range of motion and strengthening supporting muscles of the upper extremity without placing undue stress on the repaired distal biceps tendon.4 Rehabilitation is typically divided into two phases: (1) immobilization in a cast or hinged elbow brace for a period of 6 weeks4 and (2) strengthening and return to functional activity. The use of a hinged elbow brace with an extension restriction initially set at 60 degrees of flexion and allowing an additional 20 degrees of extension every 2 weeks will result in achieving full extension range of motion 6 weeks following surgical repair.13 Generalized wrist, shoulder, and scapular stabilizer strengthening can be initiated as quickly as 2 weeks after surgical repair, with the addition of strengthening exercises for elbow flexion and forearm supination beginning as early as 8 weeks following repair.3,4,13 If full active range of motion is achieved before the sixth week of rehabilitation, light strengthening of the biceps brachii may be possible.4 Patients should anticipate a return to unrestricted activities, including lifting, 5 to 6 months following surgical repair.3
When debating the merits of surgical versus non-surgical treatment, clinicians should consider the patient's age, functional activity level, and goals following injury. Research demonstrates that surgical outcomes typically result in near normal range of motion and strength, regardless of which procedure is performed.10,14 However, patients undergoing non-surgical care have lower patient satisfaction regarding subjective measures of function and demonstrate a significant loss of supination (40% to 50% deficit), elbow flexion (30% to 40% deficit), and grip strength (15% deficit) following distal biceps tendon ruptures.14
A limitation of the current case was the failure to use patient-reported outcome measures during the rehabilitation process. Recommended patient-reported outcome measures in patients suffering distal biceps tendon ruptures include the DASH outcome measure, Kerlan-Jobe Orthopaedic Clinic (KJOC) Score, and Mayo Elbow Score.
The current case is unique because the patient had a failed surgical repair that was performed within 10 days of the initial distal biceps tendon rupture. The short time frame from injury to tendon repair makes the occurrence of a failed surgery even more unique. The most likely reason for the failed surgical repair is due to the short period of immobilization and the aggressive rehabilitation program that included elbow and forearm strengthening exercises just 2 weeks after surgical repair.
- Kettler M, Tingart MJ, Lunger J, Kuhn V. Reattachment of the distal tendon of biceps: factors affecting the failure strength of the repair. J Bone Joint Surg Br. 2008;90:103–106. doi:10.1302/0301-620X.90B1.19285 [CrossRef]
- Cain RA, Nydick JA, Stein MI, Williams BD, Polikandriotis JA, Hess AV. Complications following distal biceps repair. J Hand Surg Am. 2012;37:2112–2117. doi:10.1016/j.jhsa.2012.06.022 [CrossRef]
- Ramsey ML. Distal biceps tendon injuries: diagnosis and management. J Am Acad Orthop Surg. 1999;7:199–207. doi:10.5435/00124635-199905000-00006 [CrossRef]
- Horschig A, Sayers SP, LaFontaine T, Scheussler S. Rehabilitation of a surgically repaired rupture of the distal biceps tendon in an active middle aged male: a case report. Int J Sports Phys Ther. 2012;7:663–671.
- O'Driscoll SW, Goncalves LBJ, Dietz P. The hook test for distal biceps tendon avulsion. Am J Sports Med. 2007;35:1865–1869. doi:10.1177/0363546507305016 [CrossRef]
- ElMaraghy A, Devereaux M, Tsoi K. The biceps crease interval for diagnosing complete distal biceps tendon ruptures. Clin Orthop Relat Res. 2008;466:2255–2262. doi:10.1007/s11999-008-0334-0 [CrossRef]
- Cohen MS. Complications of distal biceps tendon repairs. Sports Med Arthosc. 2008;16:148–153. doi:10.1097/JSA.0b013e3181824eb0 [CrossRef]
- Vastamäki M, Vastamäki H. A simple grafting method to repair irreparable distal biceps tendon. Clin Orthop Relat Res. 2008;466:2475–2481. doi:10.1007/s11999-008-0389-y [CrossRef]
- Kelly EW, Morrey BF, O'Driscoll SW. Complications of repair of the distal biceps tendon with the modified two-incision technique. J Bone Joint Surg Am. 2000;82:1575–1581. doi:10.2106/00004623-200011000-00010 [CrossRef]
- D'Arco P, Sitler M, Kelly J, et al. Clinical, functional, and radiographic assessments of the conventional and modified Boyd-Anderson surgical procedures for repair of distal biceps tendon ruptures. Am J Sorts Med. 1998;26:254–261. doi:10.1177/03635465980260021601 [CrossRef]
- Gupta RK, Bither N, Singh H, Kapoor S, Chhabra A, Garg S. Repair of the torn distal biceps tendon by endobutton fixation. Indian J Othop. 2012;46:71–76. doi:10.4103/0019-5413.91638 [CrossRef]
- Grewal R, Athwal GS, MacDermid JC, et al. Single versus double-incision technique for the repair of acute distal biceps tendon ruptures: a randomized clinical trial. J Bone Joint Surg Am. 2012;94:1166–1174. doi:10.2106/JBJS.K.00436 [CrossRef]
- Cheung EV, Lazarus M, Taranta M. Immediate range of motion after distal biceps tendon repair. J Shoulder Elbow Surg. 2005;14:516–518. doi:10.1016/j.jse.2004.12.003 [CrossRef]
- Baker BE, Bierwagen D. Rupture of the distal tendon of the biceps brachii: operative versus non-operative treatment. J Bone Joint Surg Am. 1985;67:414–417. doi:10.2106/00004623-198567030-00010 [CrossRef]