Case Report of a Bifid Distal Biceps Tendon with Traumatic Rupture and Subsequent Repair of Short Head Tendon Limb.
A 64-year-old right hand dominant male, presented 2 weeks after sustaining an injury to his left elbow while lifting his invalid (ALS) adult son, who he cares for. He felt a "pop" at the time of injury with subsequent pain in the antecubital fossa and weakness upon attempted biceps curling. His past medical history was remarkable for being an active smoker (2 to 2.5 packs per day) with secondary chronic obstructive pulmonary disease. He denied any history of anabolic steroid use.
On physical exam, the patient had swelling and tenderness over the distal biceps tendon with a questionable palpable defect. Pain in the antecubital fossa was elicited with resisted forearm supination and flexion. Strength was 4/5. Radiographic examination of the left elbow was essentially unremarkable. A subsequent magnetic resonance image (MRI, Fig, 1) revealed a bifurcated distal biceps tendon with a complete tear of the short head off the radial tuberosity with proximal retraction of the tendon of approximately 2 cm. The long head of the biceps tendon was intact.
Approximately 4 weeks following his injury, the patient underwent surgical repair using a single incision anterior approach. An approximately 4 cm oblique incision was made from proximal medial to distal lateral, centered over the palpated biceps tendon, beginning approximately 2 cm distal to the antecubital flexion crease. Evaluation of the distal biceps revealed a bifid tendon with separate origins at the biceps brachii at the musculotendinous junction extending distally with a common sheath for the two tendons. The posterior musculotendinous unit (long head) inserting on the proximal ulnar aspect of the radial tuberosity was noted to be intact. The anteromedial musculotendinous unit (short head) was noted to be completely raptured and retracted approximately 3 cm from its insertion just radial and distal to the long head insertion (Fig. 2).
A transosseous repair of the short head of the biceps tendon was performed utilizing an Arthrex BicepsButton[TM] (Arthrex, Inc., Naples, Florida, USA) after whip-stitching the raptured tendon with #2 FiberWire (Arthrex, Inc.), (Fig. 3). A 5-mm unicortical bone socket was drilled at the short head radial tuberosity insertion site with the BicepsButton[TM] passed through a small drill hole in the posterior cortex engaging the cortex under fluoroscopic guidance. Following full seating and fixation of the short head, the two heads were sutured together in a side-to-side fashion using a simple stitch (Fig. 4). A posterior splint was applied with the elbow in 90[degrees] flexion and forearm supination for 2 weeks.
Six weeks following surgery, the patient regained full active range of motion, fully utilizing his elbow, including lifting, without difficulty. At subsequent follow-ups of 3 months and 12 months, the patient remained asymptomatic with full range of motion and 5/5 strength on testing both elbow flexion and resisted forearm supination. The patient remained unchanged at final 2-year follow-up.
Rupture of the distal biceps tendon represents only 3% of biceps rapture events compared to 97% at the proximal origin. (15) In one of the only studies analyzing risk factors for rapture, Safran et al. (4) report a 7.5 times greater risk of distal biceps tendon rapture in patients who smoke, with the vast majority of raptures occurring in males in their 40s on their dominant elbow. Others concur that an association with smoking exists, as seen in our patient, as well as a relationship to anabolic steroid use. (6)
Up until a case report published in 2004 by Sassmannhausen et al., (10) bifurcated distal biceps tendons were thought to be rare congenital anomalies. Subsequently, a number of anatomic and cadaveric studies have been published demonstrating that in approximately half of individuals, two distinct tendon insertions can be identified. (11-13,15) Interestingly, all of the studies agree about the footprint of the two distal insertions: the tendon of the long head lies in a more proximal, lateral position and dives deep to a more posterior location on the radial tuberosity to function as the primary supinator. Meanwhile, the tendon of the short head lies more distal, anterior, and slightly ulnar, functioning primarily as a forearm flexor. (12)
After surgical dissection was carried out in our patient, a similar footprint was discovered as the short head tendon was raptured and noted to have arisen from a point more distal and anterior to that of the intact long head tendon. Both Athwal et al. (11) and Cho et al. (12) demonstrated in their cadaveric studies that the two distal tendons were easily separated in half their specimens and that the short head tendon had a slightly wider footprint than the long head (approximately 10 to 12 mm (2) difference), which again is consistent with our own intraoperative findings.
Eames et al. (13) further elucidated insertional anatomy with their description of how the lacertus fibrosus stabilizes the short head tendon and is disrupted in cases of significant proximal retraction of the distal biceps. It is possible that many previously presumed partial thickness tears of the distal biceps might actually represent complete disruption of a single tendon bundle of a bifurcated distal biceps. An awareness of the possible presence of a bifid tendon and an isolated rapture of one of the two heads, both clinically and on MRI, allows for the correct diagnosis and opportunity for possible surgical repair.
Our case report adds to the body of evidence showing that all selective raptures of bifurcated tendons involve the short head rather than the long head. To the authors' knowledge, there has been no reported isolated rapture of the long head to date. Given that tears of the distal biceps tendon characteristically occur with eccentric contraction during forced flexion, it is possible then that the short head tendon is at greater risk for selective rapture. (13,16) Nonetheless, due to the fact that many patients diagnosed with partial raptures on MRI never undergo surgical exploration, it is difficult to know the true incidence of short versus long head raptures in bifurcated tendons.
Regarding operative repair, our patient underwent cortical button fixation through a single incision approach using an anatomic footprint on the radial tuberosity in a slightly distal and anterior position. Over the past 10 years, several studies have compared different methods of distal biceps repair in both the clinical and biomechanical settings. (1-3,5,7-9) Grewal et al. (9) performed a randomized control trial comparing single versus double incision technique for repair and noted slightly increased neuropraxias (19/47 vs. 3/43, p < 0.001) and 10% worse final flexion strength in the single incision group. In contrast, a systematic review of repair techniques by Chavan et al. (3) showed no difference in complication rates between the two groups (16% vs. 18%), but rather a loss of forearm rotation motion and strength in the two-incision group.
With the increase in information regarding tendon footprint and bifurcated tendon anatomy, some hypothesize that surgeons will be able to repair raptures in a more anatomic manner, thereby improving clinical outcomes. (1518) In the only study comparing tendon reinsertion location on the radial tuberosity, Henry et al. (2) used 11 matched pairs of cadavers to compare an anterior versus posterior repair position. The biomechanical lab study found no difference in flexion force or supination torque between the anterior and posterior reconstruction groups. Further clinical studies will be needed to determine the exact functional impact of repairing distal biceps tendon ruptures in anatomic versus nonanatomic locations.
However, in the presence of an isolated tear of one of the heads of a bifid distal biceps tendon, we believe that the single incision technique allows for a more anatomic restoration of the insertional anatomy resulting in improved function.
Several methods of fixation for distal biceps tendon ruptures have been compared, including bone tunnels, interference screw fixation, suture anchor repair, and transossoeus cortical button techniques. In a large biomechanical study on fresh frozen cadaveric specimens, Mazzocca et al. (1) compared all four methods and report EndoButton[TM] fixation performed best with highest load to failure and no difference in tendon displacement. Siebenlist et al. (7) agreed with these findings when comparing suture anchors to cortical buttons. They too found higher load to failure along with less tendon-bone displacement and suggested the possibility of more aggressive postoperative protocols after button fixation.
Due to our patient's need for elbow flexion strength to care for his son as soon as possible, augmentation of the repair by side-to-side suturing of the two tendon heads was performed. We recognize that this should not be routinely performed, as the independent function of the two heads may be compromised.
Recognition of the possible anatomic variations of the distal biceps tendon is important in understanding its implication in the management of distal biceps tendon injuries. Clinical diagnosis distinguishing between true partial tendon tears and the isolated rupture of one of the heads of a bifid distal biceps tendon should be looked for on an MRI. The treatment strategy may then be decided upon, and optimal outcomes of conservative versus operative management may be determined. Awareness of the anatomy of the bifid biceps tendon variation allows the surgeon to be more precise during dissection and subsequent repair of distal biceps tendon ruptures.
None of the authors have a financial or proprietary interest in the subject matter or materials discussed herein, including, but not limited to, employment, consultancies, stock ownership, honoraria, and paid expert testimony.
(1.) Mazzocca AD, Burton KJ, Romeo AA, et al. Biomechanical evaluation of 4 techniques of distal biceps brachii tendon repair. Am J Sports Med. 2007;35(2):252-8.
(2.) Henry J, Feinblatt J, Kaeding CC, et al. Biomechanical analysis of distal biceps tendon repair methods. Am J Sports Med. 2007;35(ll):1950-4.
(3.) Chavan PR, Duquin TR, Bisson LJ. Repair of the ruptured distal biceps tendon: a systematic review. Am J Sports Med. 2008;36(8): 1618-24.
(4.) Safran MR, Graham SM. Distal biceps tendon ruptures: incidence, demographics, and the effect of smoking. Clin Orthop. 2002;(404):275-83.
(5.) Ruch DS, Watters TS, Wartinbee DA, et al. Anatomic findings and complications after surgical treatment of chronic, partial distal biceps tendon tears: a case cohort comparison study. J Hand Surg. 2014;39(8):1572-7.
(6.) Koulouris G, Malone W, Omar IM, et al. Bifid insertion of the distal biceps brachii tendon with isolated rupture: magnetic resonance findings. J Shoulder Elbow Surg. 2009;18(6):e22-5.
(7.) Siebenlist S, Buchholz A, Zapf J, et al. Double intramedullary cortical button versus suture anchors for distal biceps tendon repair: a biomechanical comparison. Knee Surg Sports Traumatol Arthrosc. 2015;23(3):926-33.
(8.) Siebenlist S, Fischer SC, Sandmann GH, et al. The functional outcome of forty-nine single-incision suture anchor repairs for distal biceps tendon ruptures at the elbow. Int Orthop. 2014;38(4):873-9.
(9.) 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(13):1166-74.
(10.) Sassmannshausen G, Mair SD, BlazarPE. Rupture of abifurcated distal biceps tendon. A case report. J Bone Joint Surg Am. 2004;86-A(12):2737-40.
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(12.) Cho CH, Song KS, Choi IJ, et al. Insertional anatomy and clinical relevance of the distal biceps tendon. Knee Surg Sports TraumatolArthrosc. 2011;19(11): 1930-5.
(13.) Eames MHA, Bain GI, Fogg QA, van Riet RP. Distal biceps tendon anatomy: a cadaveric study. J Bone Joint Surg Am. 2007;89(5): 1044-9.
(14.) Jarrett CD, Weir DM, Stuffmann ES, et al. Anatomic and biomechanical analysis of the short and long head components of the distal biceps tendon. J Shoulder Elbow Surg. 2012;21(7):942-8.
(15.) Kulshreshtha R, Singh R, Sinha J, Hall S. Anatomy of the distal biceps brachii tendon and its clinical relevance. Clin Orthop. 2007;456:117-20.
(16.) Thomas S, Shute APK. Isolated rupture of a single bundle of a bifid distal biceps brachii tendon: Case report and literature review. Curr Orthop Pract. 2013;24(1):108-10.
(17.) Voleti PB, Berkowitz JL, Konin GP, Cordasco FA. Rupture of the short head component of a bifurcated distal biceps tendon. J Shoulder Elbow Surg. 2017;26(3):403-8.
(18.) Cho CH, Song KS, Lee SM. Isolated short head component rupture of a bifurcated distal biceps tendon mimicking as a complete rupture. J Hand Surg Eur Vol. 2011;36(4):333-4.
Vinay K. Aggarwal, MD, and Donald Rose, MD
Vinay K. Aggarwal, MD, and Donald Rose, MD, Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, NYU Langone Health, New York, New York, USA.
Correspondence: Donald Rose, MD, Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, NYU Langone Health, 301 East 17th Street, New York, New York 10003, USA; Vrose2000@aol.com.
Caption: Figure 1 Sagittal T2 MRI image depicting complete rupture of the short head insertion of the distal biceps tendon (left arrow), with intact insertion of the long head onto the radial tuberosity (right arrow).
Caption: Figure 2 Intraoperative dissection demonstrating ruptured short head tendon with associated scar tissue at distal tendon stump (lower arrow), and intact long head tendon (upper arrow). To view this figure in color, see www.hjdbulletin.org.
Caption: Figure 3 Short head tendon whip stitched prior to insertion into radial tuberosity using the #2 FiberWire suture (Arthrex). To view this figure in color, see www.hjdbulletin.org.
Caption: Figure 4 Postoperative result after insertion and fixation of the short head tendon using a cortical button into the radial tuberosity with confirmation on fluoroscopy. To view this figure in color, see www.hjdbulletin.org.
Please Note: Illustration(s) are not available due to copyright restrictions.
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|Author:||Aggarwal, Vinay K.; Rose, Donald|
|Publication:||Bulletin of the NYU Hospital for Joint Diseases|
|Date:||Apr 1, 2019|
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