Shoulder & Elbow. ISSN 1758-5732

E C A S E R E P O R T

Isolated rupture of the separate insertion of the short headof biceps on the radial tuberosity: ultrasound and magneticresonance imaging diagnosis with successful surgicaltreatmentCaroline Witney-Lagen∗ , Swathy Kothapalli∗ , Richard Robinson† & Balachandran Venkateswaran∗∗Department of Orthopaedics, Dewsbury and District Hospital, West Yorkshire, UK†Department of Musculoskeletal Radiology, Dewsbury and District Hospital, West Yorkshire, UK

ReceivedReceived 20 April 2012;accepted 12 March 2013

KeywordsBiceps, short head, distal, rupture, tendon,radial tuberosity

Conflicts of InterestNone declared

CorrespondenceCaroline Witney-Lagen, Department ofOrthopaedics, Dewsbury and District Hospital,Halifax Road, West Yorkshire WF13 4HS, UK.Tel.: 44 (0)8448 118110.Fax: 44 (0)1924 816081.E-mail: carolinejws@gmail.com

DOI:10.1111/sae.12019

ABSTRACT

We report a case of isolated rupture of the separate insertion of the short head of biceps on the radialtuberosity. This case occurred in a 52-year-old male fitness instructor who lifted a heavy weight. The patientpresented with pain, bruising of the anterior elbow and weakness of elbow flexion. There was no bunchingof the distal biceps and the hook test was normal. The rupture and location of the tendon ends was identifiedby several transverse and longitudinal ultrasound images and then definitively confirmed by magneticresonance imaging. The rupture was surgically repaired, resulting in good functional ability. Early detectionis vitally important for optimal management, especially when functional disability is present.

INTRODUCTIONLittle is known about the likely presenting symptoms and signsor risk factors for isolated rupture of the separate insertion of theshort head of biceps on the radial tuberosity. Optimal investigationand management plans are also unclear. We report a case ofrupture of the separate insertion of the short head of biceps on theradial tuberosity. We review the relevant anatomy, likely clinicalsigns and symptoms, as well as risk factors, and also describe theinvestigation and management of the condition.

CASE REPORTA 52-year-old male fitness instructor presented with sudden onsetof pain and weakness in his dominant right arm after lifting a heavyweight. The injury occurred with the arm in supination, duringrepetitions of a 60-lb biceps curl. He was previously fit and well andwas not taking any regular medications. There was no history ofsmoking or steroid use. His main concerns were pain and bruisingin the upper forearm, associated with weakness of elbow flexion.

On examination, he was tender over the anterior aspect of thelower arm. The Popeye sign or palpable soft-tissue lump normallyassociated with distal biceps ruptures was absent. Bruising overthe anterior aspect of the elbow was evident. Examination ofmuscle power revealed significant weakness of elbow flexionand minor weakness of forearm supination. The patient’s elbowflexion strength was easily overcome by the examining orthopaedic

surgeon. However, his supination strength was greater than theresisting surgeon but still weaker than his unaffected normal side.The hook test was performed by the examiner using their indexfinger to palpate or hook under the biceps tendon from the lateralside of the elbow when the patient actively supinated the flexedelbow. A cord-like structure was palpable, thereby constituting anormal hook test. Sensation, capillary refill and pulses were intact.Despite the absence of some of the more typical clinical findings,and because of the patient’s typical history associated with hiselbow pain, elbow bruising and flexion weakness, a provisionaldiagnosis of distal biceps tendon rupture was made.

Plain radiographs of the elbow were normal. Ultrasoundexamination was performed by a musculoskeletal radiologist.A combination of several transverse and longitudinal imagesdemonstrated an intact distal long head of biceps tendon tracedto the proximal aspect of the radial tuberosity with rupture of thedistal short head contribution and subsequent tendon retraction.Fluid was seen interpositioned in the tendon gap and a retractionof 8 cm was present. To confirm the rare diagnosis, magneticresonance imaging (MRI) was performed. This corroborated theultrasonographic findings. Figure 1 demonstrates the intact longhead of biceps tendon extending down towards the radialtuberosity. The expected position of the short head on this imagehas been replaced by bright white fluid or haemorrhage. Instead,the end of the torn and retracted short head tendon can be seen

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Fig. 1 Sagittal proton density fat-suppressed image demonstrating thedark-coloured taught intact long head of biceps tendon (arrowheads)extending down towards the radial insertion. Extensive bright white softtissue oedema is seen predominately on the superficial aspect of thetendon corresponding to the expected position of the short head tendon.

Fig. 2 Sagittal proton density fat-suppressed image in a position medialto Fig. 1. The torn retracted short head tendon (arrow) is seen withsurrounding fluid/haemorrhage lying clearly proximal to the joint line. Thelow signal structure seen deep to the retracted tendon end is the brachialartery (arrowheads).

in Fig. 2, clearly lying proximal to the joint line and, consequently,lying far away from its expected insertion on the radial tuberosity.Figures 3 and 4 demonstrate the attachment of the long headtendon to the radial tuberosity on axial and coronal MRI images,respectively. This long head contribution could be traced proximallyfrom the radial tuberosity on sequential images but cannot bevisualized on a single image because it crosses the imaging plane.

Fig. 3 Axial proton density fat-suppressed image revealing the intactlong head of biceps tendon insertion (arrow) onto the radial tuberosity(asterisk). The long head tendon could be traced proximally on sequentialaxial images to the musculotendinous junction.

Fig. 4 Coronal proton density fat-suppressed image demonstrating thedistal long head of biceps tendon attachment (arrowheads) to the radialtuberosity (asterisk). The whole length of intact tendon could be tracedproximally on sequential images but cannot be visualized on a singleimage because it crosses the imaging plane.

As the patient was physically extremely active, he wanted tomaximize his strength and function and therefore elected toproceed with surgical repair. This was performed within 3 weeksof his injury. A percutaneous approach was used, with one smalltransverse incision above the elbow crease and one small directposterior incision over the tuberosity. The transverse incisionallowed identification of the proximal portion of tendon. The

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posterior incision allowed access to the radial tuberosity, whichwas prepared by roughening up the cortex using a hand-heldrasp. The retracted portion of the short head tendon was graspedwith a suture and advanced down to the radius with the radiusmaximally supinated. This technique remains within the tendontract and therefore does not stray radially, thus avoiding the needfor dissection of the radial nerve. This ensures that the radial nerveis not placed at risk. In addition, having two incisions achieves goodvisualization of the distal insertion site on the radial tuberosity atthe same time as allowing minimal-incision access. The desiredinsertion point was determined by palpation along the tendonfrom the transverse anterior incision and by bimanual palpationalso using the posterior incision. The chosen insertion point on theradial tuberosity was located both distally and closest to the axisof rotation. This point most closely reflects the normal anatomicalinsertion. The tendon was then fixed to bone using a GII boneanchor (DePuy Mitek, Raynham, MA, USA) with the elbow at 90◦ offlexion and full supination.

Postoperatively, we used an incremental range-of-movementprogramme to help promote tendon repair [1]. Immediatelypostoperation, the patient was immobilized for 2 weeks in anelbow brace at 90◦ of elbow flexion and full supination. After2 weeks, active elbow extension and full passive flexion (to 130◦)was allowed. However, the brace was adjusted to block the terminal60◦ of extension. After 4 weeks, active elbow flexion was allowedand the brace was further adjusted to block only the terminal30◦ of extension. At the end of the sixth postoperative week,the brace was removed and full elbow extension was allowed.Gentle physiotherapy exercises were commenced. From 10 weekspostoperatively, exercises against resistance were commenced.At 4 months, full strength in elbow flexion and supination wereseen and noncontact sports were allowed. At 6-month review, thepatient had returned to full function and sport, including kayaking.There have been no postoperative complications.

DISCUSSIONIn most cases, ruptures of the distal tendon of the bicepsare complete, although partial ruptures and ruptures at themusculotendinous unit have been described. The incidence ofshort head of biceps rupture is estimated to be no greater than0.5% of all bicipital tendon ruptures [2]. This includes a numberof proximal, as well as distal, tendon ruptures. Complete distalrupture of the biceps tendon is much rarer than complete proximalrupture, with an estimated incidence of only 1.2 ruptures per100,000 persons per year [3]. Consequently, isolated rupture ofthe separate insertion of the distal short head of biceps on theradial tuberosity is extremely rare and infrequently reported. To ourknowledge, there are only four published reports of isolated distalshort head rupture [4–7]. Full details of clinical signs and symptoms,risk factors and management are often not available and there is noconsensus on the best way to diagnose and manage the condition.

By contrast to the treatment of complete ruptures, it isimportant to note that the treatment of this very rare injuryhas to be individualized because there is little evidence regardingthe benefits of operative or conservative treatment. Successful

treatment requires an understanding of the anatomy, mechanismof injury, risk factors, clinical findings, imaging and functionalrequirements of the patient.

An overview of biceps tendon anatomy is useful whenconsidering tendon rupture. The long head of biceps brachiioriginates from the supraglenoid tubercle and the short headoriginates from the coracoid process of the scapula. The twomuscle heads then descend the anterior aspect of the arm wherecross-over of muscle fibre bundles is usually seen at an area that hasbeen termed the ‘goose quill’ [6]. The fibres continue into the lateralaspect of the cubital fossa and then insert onto the radial tuberosity.

Our patient was found to have an isolated rupture of theseparate insertion of the short head of biceps on the radialtuberosity. The rupture was identified on both ultrasound andMRI and was presumed secondary to a bifurcated distal bicepstendon insertion. Complete separation of the long and short headsis now considered to be more common than previously realised.A recent study reported separate distal long and short tendons in100% of distal biceps ultrasound scans performed on 30 volunteersand 75 patients [4]. Previous dissected specimen analyses found10 of 17 (59%) [8] and seven of 17 (41%) [6] specimens tohave separate long and short head muscle bellies and tendonsthroughout their whole proximal to distal course. It is now assumedthat the long and short head components have different insertionsand hence different functions. The long head inserts onto theradial tuberosity proximally and furthest from the axis of rotation,thereby providing supination. However, the short head insertsmore distally, thereby allowing for increased elbow flexion power[4,6,8–10]. Consequently, it is logical that a patient with an isolatedrupture of the short head contribution to the radial tuberosity couldbe expected to have weakness of flexion, whereas a patient withisolated long head rupture could be expected to have weakness ofsupination. These separate insertions explain why our patient withhis isolated short head rupture had more weakness of flexion thanof supination. Unfortunately, the other reported cases of isolatedshort head rupture on the radial tuberosity do not state whetherflexion was weaker than supination [4–7]. A literature search forisolated rupture of the separate insertion of the long head ofbiceps on the radial tuberosity only revealed two patients. Bothpatients did not demonstrate any significant reduction in flexionstrength [4]. This could be explained by their intact short headinsertions providing flexion strength. Both patients were treatedconservatively and were reported to have a satisfactory outcome.Unfortunately, the supination strength was not reported for eitherof these patients. Although the importance of the short head forflexion and the long head for supination is clear [4,6,8–10], it islikely that the situation is not quite this simple. Recent cadavericanalysis has revealed that, although the long head is the mostefficient supinator of the supinated forearm, in the case of a neutralor pronated forearm, the short head is actually the relatively moreefficient supinator [10]. In the case of isolated short or isolated longhead rupture, it has also been argued that the inter-digitationsbetween the muscle bellies of the short and long heads at the‘goose quill’ area could account for clinical retention of musclestrength [4]. Further evaluation of patients with isolated distalshort head or long head ruptures would help to characterize the

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functional contributions of the separate insertions onto the radialtuberosity.

The most common mechanism of complete distal biceps tendonrupture is excessive eccentric tension as the arm is forced from aflexed position [3]. Our patient sustained his injury lifting a heavyweight with his dominant arm. This was also the mechanismof action in the isolated distal short head ruptures reported byKoulouris et al. [5], Sassmannshausen et al. [7] and Tagliaficoet al. [4].

Knownriskfactors forcompletedistalbicepsrupture includemalesex, fourth decade of life, dominant arm, smoking and steroids [3].Mechanical impingement on the biceps tendon during forearmrotation and hypovascularity within sections of the tendon mayalso contribute to attritional ruptures [11]. Our patient was male,aged 52 years, ruptured the dominant arm and was a nonsmokerwho did not use steroids. The patients reported by Koulouris et al.[5] and Sassmannshausen et al. [7] were male, aged 39 years to45 years, and sustained a rupture of the dominant arm. Patientage, sex and dominant arm were not recorded by Dirim et al. [6]or Tagliafico et al. [4]. Smoking status and steroid use were notrecorded in any of the reported cases.

Our clinical findings of pain on movement and on palpation ofthe cubital fossa, with bruising on the anteromedial arm were alsoreported by Koulouris et al. [5] and Sassmannshausen et al. [7].The hook test has been reported to represent a very reliable testfor diagnosing distal biceps rupture [12]. However, our patient’snormal hook test results from his intact insertion of the long headonto the radial tuberosity. Consequently, although a completedistal rupture would be expected to produce an abnormal hooktest, any patient presenting with a normal hook test could still havean isolated rupture of the distal short head insertion. We considerthat the typical history and clinical findings of bruising, weaknessand tenderness, associated with a palpable tendon as opposed toa lump of the completely ruptured tendon end, should raise thepossibility of a partial distal biceps rupture.

Dirim et al. [6] and Koulouris et al. [5] describe the use of MRIfor identifying bifid tendon insertions with isolated rupture of theseparate short head of biceps insertion on the radial tuberosity. Ourcase demonstrates the successful use of ultrasound to establishthe diagnosis, supporting the work of Tagliafico et al. [4], whosuggested that ultrasound is a valuable tool for assessing the distalbiceps insertion. However, it is clear that the success of achievingdiagnosis by ultrasound is dependant upon the experience ofthe musculoskeletal radiologist. We confirmed our ultrasounddiagnosis by performing MRI and would recommend MRI tocorroborate the finding, as well as to help with surgical planning.

The literature has shown that complete distal biceps tendonruptures treated conservatively result in reduced supination andflexion [13,14]. Therefore, in complete distal tendon ruptures,active individuals are operated upon and can expect to achievegood function, even in athletes, including weight-lifters andbodybuilders [13,15]. Surgical fixation methods in use for completerupture include bone tunnels, suture anchors, interference screwsand cortical fixation buttons. A recent review article [12] foundno evidence to support the use of one method over another,although it did report an increased risk of nerve injuries using

a single-incision technique and more heterotopic ossification inassociation with a two-incision technique.

The reported cases of isolated rupture of the separate shorthead insertion on the radial tuberosity have been treated bothconservatively and surgically. Conservative management alonewas used by Tagliafico et al. [4]. However, both Dirim et al.[6] and Koulouris et al. [5] mention using surgical managementbut, unfortunately, no operative details were available. Sassman-nshausen et al. managed their patient surgically with a two-incisiontechnique and sutures through drill holes in bone [7]. Our patientwas treated with a two-incision technique and a bone anchor.Postsurgical rehabilitation details were not available in any of thereported cases. Postoperatively, we used an incremental range-of-movement programme. We believe that this achieves a balancebetween protecting the fixation and preventing long-term stiff-ness. Furthermore, tendon repair is a dynamic process. A recentreview article [1] found that cell response to mechanical loadpromotes tendon repair. Consequently, we begin movement afteronly 2 weeks of immobilization. Clinical outcome was not recordedby Dirim et al. [6], although good clinical outcome was reportedfor the other cases.

In summary, we consider that isolated rupture of the separateinsertion of the short head of biceps on the radial tuberosityshould be considered in middle-aged male patients who presentwith a history of lifting a heavy weight with their dominant armand, subsequently, suffer pain, bruising of the anteromedial arm,weakness of flexion and a normal hook test. Ultrasound can beused to diagnose the rupture and to identify patients potentiallyamenable to surgical treatment. Surgical repair can offer a goodprognosis for functional recovery, including achievement of fullstrength and return to sporting activities.

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