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Vol 7, No 3, May/June 1999 199 Once thought to be an uncommon injury, distal biceps tendon rup- tures are being seen with increas- ing frequency. A few early reports describe satisfactory results with nonoperative treatment 1,2 or non- anatomic repair. 3 However, biome- chanical studies and clinical reports highlighting the role of the biceps muscle in elbow function have raised questions about the success of these methods. 4-8 Today, most would agree that anatomic repair to the radial tuberosity is necessary to obtain strength and endurance in supination and flexion. Anatomy The biceps muscle is the most superficial muscle in the anterior compartment of the arm. The dis- tal tendon of the biceps muscle passes deep in the antecubital fossa to insert at the radial tuberosity. The bicipital aponeurosis (lacertus fibrosus) arises from the medial aspect of the muscle belly at the junction of the musculotendinous unit and the distal biceps tendon. It passes distally and medially across the antecubital fossa, blend- ing with the fascia overlying the proximal flexor mass of the fore- arm, and inserts on the subcuta- neous border of the ulna. An appreciation of the local neuro- vascular anatomy is critical if injury to these structures is to be avoided at the time of surgical repair. The lateral antebrachial cutaneous nerve is the terminal cutaneous branch of the musculo- cutaneous nerve, which supplies sensation to the volar-lateral aspect of the forearm. This nerve pierces the deep fascia of the arm near the musculotendinous junction of the distal biceps tendon between the biceps and brachialis muscles. It exits the arm and lies in the subcu- taneous tissues of the antecubital fossa. Dr. Ramsey is Assistant Professor of Ortho- paedic Surgery, University of Pennsylvania School of Medicine, Penn Musculoskeletal Institute, Presbyterian Medical Center, Philadelphia. Reprint requests: Dr. Ramsey, Penn Musculo- skeletal Institute, Presbyterian Medical Center, One Cupp Pavilion, 39th and Market Street, Philadelphia, PA 19104. Copyright 1999 by the American Academy of Orthopaedic Surgeons. Abstract Rupture of the distal biceps tendon occurs most commonly in the dominant extremity of men between 40 and 60 years of age when an unexpected extension force is applied to the flexed arm. Although previously thought to be an uncom- mon injury, distal biceps tendon ruptures are being reported with increasing frequency. The rupture typically occurs at the tendon insertion into the radial tuberosity in an area of preexisting tendon degeneration. The diagnosis is made on the basis of a history of a painful, tearing sensation in the antecubital region. Physical examination demonstrates a palpable and visible deformity of the distal biceps muscle belly with weakness in flexion and supination. The ability to pal- pate the tendon in the antecubital fossa may indicate partial tearing of the biceps tendon. Plain radiographs may show hypertrophic bone formation at the radial tuberosity. Magnetic resonance imaging is generally not required to diagnose a complete rupture but may be useful in the case of a partial rupture. Early surgical reattachment to the radial tuberosity is recommended for optimal results. A modified two-incision technique is the most widely used method of repair, but anterior single-incision techniques may be equally effective provided the radial nerve is protected. The patient with a chronic rupture may benefit from surgical reattachment, but proximal retraction and scarring of the muscle belly can make tendon mobilization difficult, and inadequate length of the distal biceps tendon may necessitate tendon augmentation. Postoperative rehabilita- tion must emphasize protected return of motion for the first 8 weeks after repair. Formal strengthening may begin as early as 8 weeks, with a return to unre- stricted activities, including lifting, by 5 months. J Am Acad Orthop Surg 1999;7:199-207 Distal Biceps Tendon Injuries: Diagnosis and Management Matthew L. Ramsey, MD The median nerve, brachial artery, and brachial vein lie medial to the biceps tendon beneath the bicipital aponeurosis. The brachial artery bifurcates at the level of the ra- dial head into its terminal branches, the radial and ulnar arteries. The radial recurrent artery branches from the radial artery and passes laterally and proximally across the antecubital fossa. The radial nerve enters the ante- cubital fossa laterally between the brachialis and brachioradialis mus- cles. Anterior to the humeral epi- condyle, the nerve divides into a superficial branch and a deep branch. The superficial branch of the radial nerve continues into the forearm under the brachioradialis and lateral to the radial artery and supplies sensation to the middorsal aspect of the forearm. The deep branch of the radial nerve (posterior interosseous nerve) courses around the lateral side of the radius and enters the supinator muscle be- tween its humeral and radial heads. Functional Biomechanics The biceps muscle is the strongest supinator of the forearm and assists the brachialis in elbow flexion. The ability of the biceps to perform these functions depends on the position of the arm. The biceps muscle is more active in flexion of the supinated forearm than in flex- ion of the pronated forearm. There is little, if any, electrical activity in the biceps muscle when flexion of the pronated forearm is attempted, unless there is a substantial pronat- ing force resisting supination. 9 Contraction of the biceps muscle tends to supinate the pronated fore- arm and may therefore be inhibited when the forearm is in pronation. The contribution of the biceps to forearm supination increases with elbow flexion, reaching a maximum at about 90 degrees of flexion. Beyond 90 degrees, there is no sub- stantial increase in biceps activity as the muscle-tendon unit shortens. 10 Etiology Rupture of the distal biceps tendon is most likely to occur in the domi- nant extremity of men between the fourth and sixth decades of life. The average age at the time of rupture is approximately 50 years (range, 18 to 72 years). 3,5-7,11-18 All reported cases of complete distal biceps ten- don rupture have occurred in men. However, partial rupture of the dis- tal biceps tendon has been reported in women. 19 The mechanism of injury is usu- ally a single traumatic event in which an unexpected extension force is applied to an arm flexed to 90 degrees. The tendon typically avulses from the radial tuberosity, although ruptures within the ten- don substance and at the musculo- tendinous junction have been reported. The bicipital aponeurosis may or may not rupture acutely. Some authors have described the rupture as occurring in stages, such that the insertion to the radial tuberosity is disrupted initially and the bicipital aponeurosis tears later, completing the rupture. 19,20 How- ever, the bicipital aponeurosis may be intact in some instances, pre- venting proximal migration of the ruptured tendon into the arm. The pathogenesis of distal biceps tendon ruptures is poorly under- stood. Degenerative and mechani- cal processes have been implicated as the cause of rupture. It is gener- ally accepted that normal tendons do not rupture. 18,21,22 The contribu- tion of a degenerative process to tendon rupture is supported by intraoperative observations of a thickened, bulbous distal end of the tendon. Microscopic characteriza- tion of spontaneously ruptured ten- dons, including the distal biceps tendon, has demonstrated an array of degenerative changes. 21 Interest- ingly, similar changes were present in control specimens from patients with no history of symptoms relat- ed to the distal biceps tendon. The degenerative process may continue unrecognized, compromising the structural integrity of the tendon, until sufficient trauma causes com- plete rupture. Hypovascularity of the tendon may play a role in tendon rupture in some patients. Vascular injection studies of the distal biceps tendon demonstrate two consistent sources of extratendinous blood supply, one distally at the tendon insertion from the posterior recurrent artery and one proximally from the brachial artery. A hypovascular zone has been identified between the proximal and distal zones. 23 The fact that most ruptures occur at the tendon insertion, as opposed to a more proximal location, would seem to eliminate hypovascularity as the sole cause of rupture. The space available for the bi- ceps tendon between the radius and the ulna changes depending on forearm position. The distance between the radius and the ulna is maximal in supination and de- creases progressively with forearm pronation. In full pronation, the bi- ceps tendon occupies 85% of the available space 23 ; therefore, any- thing that encroaches on this space may result in mechanical impinge- ment. Davis and Yassine 22 theo- rized that hypertrophic bone on the anterior margin of the radial tuber- osity contributes to tendon failure because of repetitive impingement with forearm rotation. Clinical Evaluation History and Physical Examination Patients with complete distal biceps tendon ruptures usually Distal Biceps Tendon Injuries Journal of the American Academy of Orthopaedic Surgeons 200 report an unexpected extension force applied to the flexed arm. The most common symptom asso- ciated with distal biceps tendon rupture is a sudden, sharp, painful tearing sensation in the antecubital region of the elbow and occasional- ly in the posterolateral aspect of the elbow. The intense pain subsides in a few hours and is replaced by a dull ache, which can last for weeks and may become chronic activity- related pain. Subjective weakness in supination is a variable com- plaint, which may depend on the functional demands placed on the extremity. Weakness in flexion is profound immediately after rup- ture because of pain but tends to diminish with time. Physical examination demon- strates tenderness in the antecu- bital fossa. A defect in the antecu- bital fossa can usually be palpated. If the biceps tendon is palpated in the antecubital fossa, a partial rup- ture of the distal biceps tendon must be considered. If the bicipital aponeurosis is intact, the deformity is not as pronounced but is usually easy to appreciate on comparison with the opposite extremity. With active flexion of the elbow, the biceps muscle belly retracts proxi- mally, accentuating the defect in the antecubital fossa (Fig. 1). Ecchymosis and swelling appear in the antecubital fossa and along the medial aspect of the arm and proxi- mal forearm. Weakness in supination, as well as some weakness in flexion, can usually be demonstrated. In the acute phase, weakness may be related to pain in addition to the functional deficits of the detached biceps tendon. Radiologic Evaluation Radiographic studies can aid in the diagnosis of ruptures of the dis- tal biceps tendon but are not a sub- stitute for a thorough history and physical examination. Plain radio- graphs generally do not demon- strate any osseous changes. How- ever, irregularity and enlargement of the radial tuberosity 22 and avul- sion of a portion of the radial tuberosity 3 have been reported in patients with complete ruptures of the distal biceps tendon. Inability to palpate the distal biceps tendon in the antecubital fossa is indicative of a complete rupture. If the history and symp- toms suggest a biceps tendon injury and the tendon can be pal- pated in the antecubital fossa, other causes of antecubital pain, includ- ing cubital bursitis, bicipital tendi- nosis (tendon degeneration), partial biceps tendon rupture, and entrap- ment of the lateral antebrachial cutaneous nerve, must be investi- gated. Cubital bursitis (enlargement of the bursal sac that lies between the biceps tendon and the anterior aspect of the radial tuberosity) may exist in isolation or in association with a distal biceps tendon lesion. Tendon degeneration (bicipital tendinosis) without rupture may occur in isolation or in association with cubital bursitis or partial rup- ture. In this circumstance, magnet- ic resonance (MR) imaging of the elbow may provide useful informa- tion about the integrity of the distal biceps tendon and any intrasub- stance degeneration (Fig. 2). How- ever, the distinction between bicip- ital tendinosis and partial ruptures is not always apparent on MR imaging. 24 Classification There is no widely accepted classi- fication for distal biceps tendon injuries. Partial ruptures of the dis- tal biceps tendon have been report- ed only in case reports and small series. 19,24,25 Partial tendon failure can occur at the tendon insertion to bone 19,22,24 or within the substance of the tendon, which can be elon- gated. 25 Because so few cases of partial rupture have been reported, any classification that aspires to guide treatment is subject to error. Complete ruptures are arbitrar- ily classified on the basis of the amount of time between rupture and diagnosis. In chronic tears, the integrity of the bicipital aponeuro- sis is also important because of its role as a tether to proximal retrac- tion. The value of defining the chronicity of the rupture and the integrity of the bicipital aponeuro- sis lies in its usefulness in predict- ing the ease of repair (Table 1). Distal biceps tendon ruptures diagnosed early are easily reat- tached to the tuberosity with pre- dictably good results regardless of whether the bicipital aponeurosis is intact or ruptured. 4,6-8,11,13,17,18 Matthew L. Ramsey, MD Vol 7, No 3, May/June 1999 201 Fig. 1 Proximal retraction of the biceps muscle belly with attempted flexion of the elbow. However, the results of repair of chronic ruptures vary and are not predictable solely on the basis of the time between rupture and re- pair. If the bicipital aponeurosis remains intact, the tendon is pre- vented from retracting proximally into the arm. Rupture of the distal biceps tendon and the bicipital aponeurosis allows the tendon to retract proximally. Over time, scar- ring to the brachialis and retraction of the tendon into the biceps mus- cle belly may limit the ability to obtain sufficient length for anatom- ic repair. Treatment Partial Rupture The difficulty in treating pa- tients with partial tears of the distal biceps tendon lies in proper diag- nosis. Cubital bursitis, with or without concomitant bicipital tendinosis, and partial ruptures can both present with pain in the ante- cubital fossa; furthermore, both conditions may be present at the same time. 26 The advent of MR imaging has allowed direct assess- ment of pathologic changes within soft tissue that previously could only be inferred from the history and physical examination. 27,28 This has helped define the pathology of the distal biceps tendon. Partial distal biceps tendon rup- tures that fail to respond to nonop- erative treatment are best managed surgically. Most partial ruptures occur at the insertion into the radial tuberosity. 19,22,24 The most success- ful surgical results for symptomatic partial ruptures have been achieved by releasing the remaining portion of the biceps tendon from the tuberosity, debriding the frayed tendon end, and anatomically reat- taching the tendon to the radial tuberosity as if there were a com- plete rupture. 19,24 Foxworthy and Kinninmonth 29 reported a case of median nerve compression from an enlarged synovial bursa associated with a partial rupture of less than 50% of the distal biceps tendon, which was treated with median nerve decompression and debride- ment of the biceps tendon. Whether debridement of the distal biceps tendon contributed anything to the improvement in the patientÕs symp- toms is unclear from this report. Other authors have not reported success with debridement of partial tears of the distal biceps tendon. 19 Elongation of the biceps tendon without failure at the tuberosity is an unusual form of partial tearing reported by Nielsen. 25 The thin, elongated tendon does not possess the mechanical integrity of the intact tendon and behaves clinical- ly like a complete rupture. Nielsen used Z-plasty shortening of the biceps tendon with suture rein- forcement to reestablish the length- tension relationship of the biceps muscle. Postoperatively, flexion strength and supination strength were equivalent to those in the noninjured arm. Complete Rupture The superiority of early anatom- ic repair in returning flexion and supination strength is well estab- lished. 4,6-8,11,13,17,18 Although some patients may choose nonoperative management of complete ruptures, they should be told of the possibility of activity-related pain in the arm and forearm, as well as decreased strength and endurance in flexion and supination. Nonoperative management should be considered only for elderly, sedentary patients who do not require strength and endurance in flexion and supina- tion and for patients who are too ill to undergo surgery. Single-incision and two-incision techniques to treat these injuries have been described. Recently, with the availability of suture Distal Biceps Tendon Injuries Journal of the American Academy of Orthopaedic Surgeons 202 Fig. 2 Fast spin-echo T2-weighted MR images of two patients. A, Normal distal biceps tendon insertion (arrowhead). B, Partial insertional rupture (arrowhead) with degenera- tion of the distal biceps insertion (arrow). A B Table 1 Classification of Distal Biceps Tendon Ruptures Partial rupture Insertional Intrasubstance (elongation) Complete rupture Acute (<4 weeks) Chronic (>4 weeks) Intact aponeurosis Ruptured aponeurosis anchors, the use of an anterior approach has increased in populari- ty. 16,30,31 When using suture an- chors and a single-incision tech- nique for acute distal biceps tendon ruptures, the radial nerve should be protected but does not need to be formally identified and dissected. 31 In chronic cases, the surgeon should consider identifying the superficial and deep branches of the radial nerve to avoid injury if a single anterior incision is to be utilized. In this situation, a pullout suture tied over a bolster or soft-tissue button or suture anchors are used. 7,13,16,17 Before suture anchors became avail- able, radial nerve injuries were reported with single-incision tech- niques, 3,5,7,12 which prompted the development of two-incision tech- niques. 8,14,32 Most authors favor a modified Boyd-Anderson two-incision tech- nique for complete ruptures. The original technique involves subpe- riosteal exposure of the ulna. 32 This approach has caused radioulnar synostosis, 8,12,33 prompting modifi- cation of the technique. Currently, a muscle-splitting approach through the common extensor and supinator muscles is preferred. Although this may reduce the incidence of proxi- mal radioulnar synostosis, it has not eliminated it entirely. 15 Technique for Immediate Repair The patient is placed supine on the operating room table with the affected arm extended on an arm board. A tourniquet can be used if desired. An anterolateral incision beginning 5 cm above the flexion crease along the lateral border of the biceps is the standard ap- proach. The incision should curve medially at the flexion crease of the elbow to avoid crossing the elbow at a 90-degree angle to the flexion crease. This extensive exposure is unnecessary in acute ruptures; a transverse incision in the flexion crease with distal extension pro- vides adequate exposure and a cos- metically acceptable incision. The lateral antebrachial cutaneous nerve is identified as it pierces the deep fascia and is retracted lateral- ly. The deep fascia is incised, and the distal biceps tendon is identi- fied. If the bicipital aponeurosis is intact, the tendon will remain in the tendon sheath or will retract proximally and turn back on itself in the antecubital fossa. If the bicipital aponeurosis is ruptured, the tendon will retract proximally into the anterior compartment of the arm. The tendon is retrieved and minimally debrided. Two No. 5 nonabsorbable Bunnell sutures are passed through the tendon. If the rupture is acute or the ten- don remains in the tendon sheath distally, an extensive soft-tissue dis- section, including identification of the radial nerve, is not necessary. The sheath previously occupied by the biceps tendon can be easily identified by blunt finger dissection down to the radial tuberosity. With the forearm in supination, a blunt hemostat is advanced along the medial border of the radial tuberos- ity to the dorsolateral aspect of the proximal forearm; care must be taken not to violate the periosteum of the ulna (Fig. 3). A second incision is made over the hemostat down to the fascia overlying the common extensor muscle mass. The common exten- sor muscle mass and supinator muscles are split down to the radial tuberosity with the forearm in max- imal pronation. A high-speed burr is used to create a cavity in the radi- al tuberosity large enough to accept the distal biceps tendon. Three small drill holes are placed along the margin of the cavitated tuberos- ity. The sutures are passed from the anterior incision through to the second incision (Fig. 4). The tendon is passed deep and medial to the lat- eral antebrachial cutaneous nerve. The sutures are passed through the drill holes and tied. The wounds are closed in layers, and the elbow is immobilized in 90 degrees of flex- ion with the forearm in supination. Technique for Delayed Repair The need to repair chronic rup- tures of the distal biceps remains questionable. Chronic ruptures are more difficult to repair than acute ruptures. However, the disability Matthew L. Ramsey, MD Vol 7, No 3, May/June 1999 203 Fig. 3 A, The ulnar periosteum is not exposed in the modified muscle-splitting two-inci- sion technique (dotted line shows correct direction of incision). B, Care must be taken not to violate the ulnar periosteum when passing the hemostat to the dorsolateral aspect of the forearm or when making an incision on that surface (dotted line shows incorrect direction of incision). Correct Incorrect A B associated with a chronic rupture often justifies the attempt at repair even though the results are not as predictable as those after immedi- ate repairs. Anatomic repair of the ruptured tendon to the tuberosity is the goal of delayed repair if improved strength and endurance are neces- sary. If surgery is being performed because of activity-related pain in the arm and forearm, tenodesis to the brachialis can be considered, with the understanding that supi- nation strength and endurance will not improve. Proximal retraction of the rup- tured tendon may preclude ana- tomic reattachment because of a loss of tendon length. An intact bicipital aponeurosis will limit proximal retraction of the tendon, making repair somewhat easier. Inadequate tendon length should be anticipated preoperatively and discussed with the patient so that an alternative source of graft to extend the tendon can be planned. Autogenous tissue is preferred to synthetic materials. Rolled fascia lata or semitendinosus autograft are acceptable graft mate- rials. The semitendinosus tendon is similar in caliber to the native biceps tendon and has performed well in clinical use. 34 In cases of chronic rupture, the distal biceps tendon sheath is scarred, necessitating a more exten- sive dissection. Identification and protection of the radial nerve are warranted in this situation. The graft should be passed from anterior to the posterolateral incision and fixed to the tuberosity, as de- scribed for an immediate repair. With the elbow in 45 to 60 degrees of flexion, the graft is woven through the distal end of the native biceps tendon and secured to itself (Fig. 5). Postoperative care is similar to that for immediate repairs. Postoperative Rehabilitation The extremity is immobilized with the elbow in 90 degrees of flex- ion and the forearm in supination for 7 to 10 days. A hinged flexion- assist splint with a 30-degree exten- sion block is used to protect the re- pair until 8 weeks postoperatively. The splint is then removed, and un- restricted motion and progressive strengthening are begun. Unre- stricted activities, including strenu- ous lifting, are not allowed until 5 months after repair. The rehabilitation program for patients with delayed repairs is similar to that for patients with acute repairs. The limit of active extension in the early postoperative period is dictated by the tension in the biceps tendon. Results As mentioned previously, numer- ous early reports on the treatment of distal biceps tendon ruptures indi- cated that satisfactory results could be obtained, with return of normal or near-normal strength and func- tion, regardless of the method of treatment. Some authors advocated nonoperative management of these injuries, citing normal return of strength and function and docu- menting the ability to return to work earlier than after surgical treatment. 1,2 Other authors sup- ported attachment of the biceps ten- don to the brachialis muscle. 4,12 This position was historically advo- cated in 1941 by Dobbie, 12 who was Òimpressed with the numerous important structures identified and contained in this anatomic region Distal Biceps Tendon Injuries Journal of the American Academy of Orthopaedic Surgeons 204 Fig. 4 The exposed tuberosity is excavated with a high-speed burr, taking care to leave the thicker cortical bone along the radial border of the tuberosity intact. Three drill holes are made along the radial side of the tuberosity. The sutures are passed through the drill holes and tied with the forearm in neutral position to prevent the sutures from pulling out of the drill holes. (Adapted with permission from the Mayo Clinic, Rochester, Minn.) Biceps tendon and was thoroughly convinced that exposure of the tubercle was impractical and unwise.Ó Reattach- ment of the biceps tendon to the brachialis muscle simplified the sur- gical procedure considerably and avoided the potential complication of radial nerve injury. 3,12 However, objective strength data demonstrate no improvement in supination strength. 8 As the role of the biceps muscle in elbow strength and function became known, support for early anatomic repair grew. In 1985, Morrey et al 8 reported loss of flexion and supination strength by as much as 50% with nonoperative treatment. Similarly, Baker and Bierwagen 4 documented objective deficiencies in flexion and supination strength of 21% and 27%, respectively. Equally impressive were the losses of flexion and supination endurance, estimat- ed at 21% and 47%, respectively. While this degree of loss of strength may not be incapacitating for many activities of daily living, activities that require sustained strength and endurance can be severely limited. When one considers that this injury occurs most frequently in the domi- nant extremity in heavy laborers, it is not surprising that these deficits can be disabling. Surgical repair is the more re- cently accepted approach. Nu- merous studies have reported ex- cellent results with early anatomic repair of the distal biceps ten- don. 4,6-8,11,13,17,18 Morrey et al 8 reported 97% flexion strength and 95% supination strength compared with the uninvolved extremity. Other authors have demonstrated similar return of strength and en- durance but have reported differ- ences based on hand dominance. Repaired nondominant extremities demonstrated mild weakness and lack of endurance compared with the uninvolved dominant extremi- ty; however, strength and endur- ance of the repaired dominant ex- tremity were equivalent to those in the unrepaired nondominant ex- tremity. 4,11,15 Patients with chronic ruptures (>4 weeks) present a difficult chal- lenge. Proximal retraction of the biceps muscle and scarring to the brachialis can occasionally make anatomic repair impossible. Fascia lata autograft, 3,13 a semitendinosus autograft, 34 and a ligament aug- mentation device wrapped with fascia lata 20 have all been used to extend a shortened biceps muscle. Strength in flexion and supination is improved in comparison to rup- tured tendons treated nonopera- tively, but the degree of improve- ment varies. 5,8,34 Boucher and Mor- ton 5 reported 50% residual flexion weakness in a patient treated 4.5 months after injury. Hang et al 34 found only 13% flexion and 14% supination deficits in a patient treated with semitendinosus aug- mentation 1 year after injury. Al- though late repairs carry a greater risk of providing no improvement in strength, surgery should be con- sidered for patients with consider- able disability. When partial rupture of the dis- tal insertion has been successfully managed by releasing the remain- ing tendinous insertion to the tuberosity and reattaching the ten- don as if it were completely rup- tured, patients have been able to return to normal work activities without difficulty. 19,24 Bourne and Morrey 19 evaluated postoperative strength data after release and repair of partially ruptured ten- dons and found normal values in one patient and a decrease by 33% in supination with normal flexion strength in a second patient. Nielsen 25 has reported a case of biceps tendon elongation with mechanical insufficiency of the biceps muscle. After nonoperative treatment failed to improve the patientÕs symptoms, a Z-plasty shortening of the tendon was per- formed, which restored power to the extremity. Complications Many authors have reported radial nerve injury after repair with the use of a single-incision anterior approach. 3,5,7,18 Fortunately, when a radial nerve palsy occurs, it typi- cally resolves completely, although permanent radial nerve injury has been reported. 3 Although a two-incision repair decreases the incidence of radial nerve injury, proximal radioulnar Matthew L. Ramsey, MD Vol 7, No 3, May/June 1999 205 Fig. 5 The semitendinosus graft is secured to the radial tuberosity through drill holes. With the arm in 45 to 60 degrees of flexion, the graft is woven through the distal biceps tendon stump and secured to itself. (Adapted with per- mission from Hang DW, Bach BR Jr, Bojchuk J: Repair of chronic distal biceps brachii tendon rupture using free autoge- nous semitendinosus tendon. Clin Orthop 1996;323:188-191.) synostosis has been reported as a potential complication of this ap- proach. 8,12,15,33 Use of a muscle- splitting approach instead of the original technique of subperiosteal ulnar dissection may reduce the incidence of this complication. Summary Rupture of the distal biceps tendon can be disabling for individuals who require upper extremity strength for vocational and recreational activi- ties. It occurs when an unexpected extension force is applied against a contracting biceps muscle. Rupture probably occurs through a tendon weakened by intrasubstance degen- eration or external mechanical im- pingement. The history and physical exami- nation are usually sufficient to make the diagnosis. The hallmark is a palpable defect in the distal biceps, which is accentuated by attempted elbow flexion. Weak- ness on supination is easily demon- strated; flexion weakness is more subtle. Radiologic evaluation, including plain radiographs and MR images, is generally not neces- sary to make the diagnosis. Mag- netic resonance imaging may occa- sionally be useful in differentiating among biceps tendon degeneration (tendinosis), cubital bursitis, and partial distal tendon ruptures. Immediate surgical repair of the ruptured biceps tendon is advocated for optimal return of function. Use of a two-incision muscle-splitting approach and nonabsorbable su- tures is recommended for secure repair. Techniques that utilize a single anterior incision are ade- quate but require protection of the radial nerve to avoid nerve injury. The use of suture anchors may sim- plify the procedure. In the case of a chronic rupture, there may be inad- equate tendon length to reach the radial tuberosity. Autogenous tis- sue or an augmentation device can be considered in this situation. The results of late repair are less pre- dictable for return of strength, but activity-related pain is diminished. Symptomatic partial tendon ruptures are rare. Failure of non- operative management may be treated by release and repair of the partially torn tendon. However, experience with surgical treatment is limited. Postoperative rehabilitation involves protection of the repair against any lifting force for 6 to 8 weeks. Initially, the arm is immo- bilized in a splint with the elbow in 90 degrees of flexion and the fore- arm in supination for 7 to 10 days. A flexion-assist splint with a 30- degree extension block is utilized for 6 to 8 weeks postoperatively. Unrestricted range-of-motion exer- cises and gentle strengthening are begun at 8 weeks. Return to unre- stricted activity is allowed by 5 months after surgery. Distal Biceps Tendon Injuries Journal of the American Academy of Orthopaedic Surgeons 206 References 1.Carroll RE, Hamilton LR: Rupture of biceps brachii: A conservative method of treatment [abstract]. 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