Distal biceps tendon history, updates, and controversies: from the closed American Shoulder and Elbow Surgeons meeting—2015

ARTICLE IN PRESS J Shoulder Elbow Surg (2016) ■■, ■■–■■

www.elsevier.com/locate/ymse

Distal biceps tendon history, updates, and controversies: from the closed American Shoulder and Elbow Surgeons meeting—2015 Christopher C. Schmidt, MDa,*, Felix H. Savoie III, MDb, Scott P. Steinmann, MDc, Michael Hausman, MDd, Ilya Voloshin, MDe, Bernard F. Morrey, MDc, Dean G. Sotereanos, MDa, Emily H. Bero, BSf, Brandon T. Brown, MMEg a

Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA Department of Orthopaedics, Tulane University, New Orleans, LA, USA c Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA d Department of Orthopaedics, Mount Sinai Hospital, New York, NY, USA e Department of Orthopaedics, University of Rochester, Rochester, NY, USA f Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA g Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA b

Understanding of the distal biceps anatomy, mechanics, and biology during the last 75 years has greatly improved the physician’s ability to advise and to treat patients with ruptured distal tendons. The goal of this paper is to review the past and current advances on complete distal biceps ruptures as well as controversies and future directions that were discussed and debated during the closed American Shoulder and Elbow Surgeons meeting in 2015. Level of evidence: Narrative Review © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. Keywords: History distal biceps tendon; anatomy distal biceps; anatomic biceps repair; posterior approach; anterior approach; high-flexion biceps repair; biceps tendon augmentation; endoscopically assisted repairs

History The first known case of direct suture of the distal biceps tendon to the radial tuberosity occurred in 1898, and the first reported use of a tendon fixation device, a nail, happened in 1928.21 Our current knowledge of distal biceps disease and surgical treatment arguably started in 1941 when Robert P. *Reprint requests: Christopher C. Schmidt, MD, Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, 9104 Babcock Blvd, Suite 5113, Pittsburgh, PA 15237, USA. E-mail address: [email protected] (C.C. Schmidt).

Dobbie reviewed the known 24 cases of complete distal biceps avulsions in the literature and reported on 51 new cases.21 Dobbie’s clinical observations were that the biceps tendon attaches posteriorly on the radial tuberosity and the tendon ruptures off bone with little remnant. An anterior approach between the brachioradialis and pronator teres provides good tendon exposure, however Dobbie believed a repair back to the radial tuberosity was “impractical and unwise” due to an unacceptable rate of radial nerve palsies, 4.4% (2/51), which is similar to today’s rate, 3.2% (9/280).21,63 Dobbie further recommended biceps to brachialis transfer to prevent radial nerve injury and to improve elbow flexion; he believed “the

1058-2746/$ - see front matter © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. http://dx.doi.org/10.1016/j.jse.2016.05.025

ARTICLE IN PRESS 2 supinative power of the biceps is of secondary importance and can be ignored.”21 Other early investigators also thought that repair to bone using an anterior approach was associated with an unacceptably high rate of radial nerve palsies, 50% (3/6), and therefore advised a biceps to brachialis transfer for definitive treatment.57 During the 1960s, a number of physicians advocated nonoperative treatment for biceps ruptures, prescribing weight training exercise.13 Carroll and Hamilton reviewed the results of 100 patients with complete biceps ruptures; 10 of these injuries were distal injuries, and those 10 patients returned to work, on average, at 4 weeks without loss of supination strength at 1-year follow-up.13 However, Friedmann noted weakness in elbow flexion and supination with conservative care but reported that a few patients were able to “overcompensate in satisfactory fashion.”29 Patients were observed adapting to their supination strength loss by excessively using the shoulder muscles.57 They involuntarily abduct the shoulder and then adduct the arm while externally rotating the forearm to increase supination power. 57 Some surgeons began to recognize the importance of repairing the ruptured tendon to the radial tuberosity in an attempt to recover lost supination strength and endurance.5,10,11,29 This breakthrough came in 1961, when Boyd and Anderson published a case series of 3 patients using a 2-incision approach that, in theory, limits radial nerve injury while providing ample room to reattach the tendon to the radius.11 An anterior incision is made to harvest the retracted tendon, the tendon is passed from front to back between the pronator teres and brachioradialis, and a second posterior incision is made between the ulna and anconeus to retrieve the tendon and suture it to bone. Their procedure was revolutionary because unlike the biceps to brachialis transfer, the repair addressed the loss of supination strength.11 Two landmark articles in 1985, published back-to-back in Journal of Bone and Joint Surgery, clearly showed that the 2-incision approach was superior to nonoperative care.5,60 Patients treated nonoperatively experienced difficulties with activities that required repetitive forceful supination and flexion, like turning a screwdriver or swinging a baseball bat.5 Mechanical testing showed a 40% loss of supination strength, 79% loss of supination endurance, 30% loss of flexion strength, and 30% loss of flexion endurance.60 With dissemination of the 2-incision approach, other investigators started to report a concerning occurrence of motionlimiting heterotopic bone (HO) formation between the proximal radius and ulna.18,25,45,50,60 Morrey and coinvestigators noted that a traditional Boyd and Anderson approach raises the anconeus off the ulna and in doing so damages its periosteum and possibly the interosseous membrane.25,59 The injury to the periosteum and interosseous membrane was postulated to cause excessive HO formation. To prevent symptomatic HO, the authors recommended splitting the extensor carpi ulnaris (ECU) or the extensor digitorum communis (EDC) instead of elevating the anconeus.25,59 In addition, further effort was made to remove all bone debris created during trough

C.C. Schmidt et al. burring.25,59 They named the new surgical approach the modified 2-incision technique.25,59 To be consistent with modernday terminology, the remaining parts of this article refer to the modified 2-incision approach as the posterior approach. In a subsequent study using their posterior approach, the authors reported no motion-limiting HO (0% [0/74]).46 This technique is the current “gold standard” repair.78 However, a subsequent retrospective review questioned the success of the posterior approach by reporting a 7% (3/45) occurrence of motion-limiting HO.8 Of note, HO limiting forearm rotation has also been reported in association with an anterior approach.2,92 A recent randomized clinical trial comparing anterior to posterior approaches in repairing the distal biceps reported no clinically significant occurrence or statistical difference (P = .7) in HO formation between the groups (anterior, 1/47 mild HO; posterior, 1/43 mild HO).31 Unless it is contraindicated, indomethacin 25 mg 3 times daily was prescribed for 3 weeks postoperatively in both groups.31 Invention of new fixation devices, fear of HO, and the belief that early active motion might improve clinical results revitalized interest in the anterior approach.4,6,30,44,52,56,86,89 The search for the strongest fixation device led to a plethora of timezero cyclic and load-to-failure studies.7,30,41,47,48,55,67,81,82,87 The results of the mechanical strength studies demonstrated that cortical buttons are mechanically superior to suture anchors or interference screws.30,48,55,81-83 However, clinical studies using suture anchors, cortical buttons, and combinations of a button and interference screw all reported similar rerupture rates (0% to 4%) with acceptable clinical results and return of peak strength tested in a neutral forearm position.16,31,38,65 Accelerated motion using both anterior and posterior approach programs has reduced the risk of elbow stiffness after repair, but early motion must be balanced against the risk of rerupture. Studies vary widely, with postoperative protocols ranging from 6-week cast immobilization to immediate active range of motion with a 6-week 1-pound weight restriction.12,15,16,30,31,35,38,77 Rerupture tends to occur during the first 14 days after repair as a result of a traumatic accident or the patient’s noncompliance.16,31,38,44 To our knowledge, rerupture 6 weeks after repair has not been reported.16,38 No method of initial fixation has proved superior over another to prevent a rerupture.12,16,31,38,56 It stands to reason that patients should be instructed to avoid lifting or turning any object weighing >1 pound for the first 6 weeks after repair.

Anatomy, tendon force transmission, and repair biology The distal biceps tendon is composed of a long and a short head, which attaches to the posterior aspect of the radial tuberosity3,21,22,42 (Fig. 1). On axial imaging, it can clearly be seen that the center of the biceps tendon attaches 24.0° ± 8.0° anterior to the apex of the radial tuberosity or 6.7 mm ± 1.4 mm anterior to the apex74,77 (Fig. 2). The short head is medial to the long head at the myotendinous junction; the tendon then

ARTICLE IN PRESS Distal biceps tendon

3

Figure 1 A cadaveric dissection illustrating the short and long heads. Both heads insert on the posterior aspect of the tuberosity. The short head inserts distal to the long head. (From Jarrett CD, Weir DM, Stuffmann ES, Jain S, Miller MC, Schmidt CC. Anatomic and biomechanical analysis of the short and long head components of the distal biceps tendon. J Shoulder Elbow Surg 2012;21:942-8. Reprinted with permission from Elsevier.)

Figure 3 Schematic and picture illustrating the external rotation of the biceps tendon from proximal to distal. (A) Schematic illustrating the 90° external rotation of the distal biceps tendon. (From Schmidt CC, Jarrett CD, Brown BT. The distal biceps tendon. J Hand Surg Am 2013;38:811-21. Reprinted with permission from Elsevier.) (B) Cadaveric dissection showing that the short head begins medial and ends distal to the long head of the distal biceps tendon. LH, long head; SH, short head; R, radius; U, ulna; A, anterior.

Figure 2 The center of the biceps tendon inserts at an angle of 24.0° ± 8.0°77 or a length of 6.7 mm ± 1.4 mm74 anterior to the tuberosity. BT, biceps tendon; AL, arc length. (From Schmidt CC, Diaz VA, Weir DM, Latona CR, Miller MC. Repaired distal biceps magnetic resonance imaging anatomy compared with outcome. J Shoulder Elbow Surg 2012;21:1623-31. Reprinted with permission from Elsevier.)

externally rotates 90° as it traverses the bicipital tunnel, and this rotation positions the short head distal to the long head on the radial footprint3,22,42 (Fig. 3). Force transmission studies show that the short and long heads have different mechanical roles and that footprint position is vital in maintaining supination torque throughout forearm rotation.42,69,80 The short head generates 15% greater flexion load than the long head because of its distal attachment, however the long head creates a greater supination

moment than the short head in a supinated forearm position because of its more posterior attachment42 (Fig. 4). In 2 cadaver mechanical studies, anterior reattachment sites were shown to decrease supination torque by 15% in neutral and by 40% in 45° of supination and to reduce supination moment arm by 27% in neutral and by 97% in 60° of supination.69,80 These mechanical studies imply that restoration of flexion and supination strength following a biceps rupture is a direct function of reattachment position and that restoration of preinjury mechanics is dependent on repair of both heads to their respective anatomic footprints. The radial tuberosity has a specialized protuberance just anterior to the biceps insertion that acts as a supination cam27,40,55,76,79 (Fig. 5). Drilling or burring a socket/trough in the tuberosity results in a 27% loss (P = .036) in the biceps supination moment arm in a supinated forearm position.76 This study proved that the biceps protuberance indeed works as a cam increasing supination performance.76 If a trough is

ARTICLE IN PRESS 4

C.C. Schmidt et al. biceps repair clearly illustrates that the tendon solidly heals to an abraded cortical surface.77 Current knowledge indicates that a trough is not a prerequisite for healing, and considering its potential deleterious effects on supination strength should cause us to rethink its utility. MRI analysis does show that the biceps tendon commonly heals with intratendinous heterogeneity and HO but these findings do not correlate with a poor clinical outcome or diminished strength.77

Figure 4 A computer-generated model of the proximal radius illustrating the anatomic footprint of the distal biceps tendon. The dot is the calculated centroid, and notice that the short head centroid is distal to the long head centroid, but the long head centroid is more posterior to the short head centroid. These different attachment locations help explain the different mechanical functions of each of the heads. (From Jarrett CD, Weir DM, Stuffmann ES, Jain S, Miller MC, Schmidt CC. Anatomic and biomechanical analysis of the short and long head components of the distal biceps tendon. J Shoulder Elbow Surg 2012;21:942-8. Reprinted with permission from Elsevier.)

Anatomic (cadaveric) repair considerations The distal biceps tendon can be reattached by an anterior approach between the brachioradialis and pronator teres muscles (forearm in hypersupination) or with a posterior approach by spitting the ECU and supinator muscles (forearm in pronation) (Fig. 6).21,59,74 Using an anterior approach, it is extremely difficult to reattach the ruptured tendon back to its anatomic footprint because of bulky forearm muscles and the pronated position of the radial tuberosity.27,34,36,43,77 Two cadaveric studies comparing anterior to posterior surgical repairs reported an anterior (nonanatomic) reattachment site with an anterior approach and an anatomic repair site using a posterior approach.36,43 Further, a computed tomography study noted that 35% of the radial tuberosities sampled were in extreme pronation, and even using an anterior approach with forearm hypersupination, a straight guide pin could not be placed into the native footprint.27 Cadaveric studies clearly demonstrate that a posterior approach provides the required exposure for

Figure 5 An axial magnetic resonance imaging cut through the biceps tendon insertion site. The protuberance (arrowhead) is a specialized geographic part of the radial tuberosity located anterior to the biceps insertion. The protuberance functions as a supination cam. A, area of radius anterior to the insertion site; P, posterior to the insertion site; R, radius; U, ulna; BT, biceps tendon). (From Schmidt CC, Brown BT, Williams BG, Rubright JH, Schmidt DL, Pic AC, et al. The importance of preserving the radial tuberosity during distal biceps repair. J Bone Joint Surg Am 2015;97:2014-23. Reprinted with permission from Journal of Bone and Joint Surgery, Inc.)

required for repair, it should be placed posterior to the protuberance.76,78 Preservation of radial skeletal anatomy seems to be essential for restoration of normal supination strength following a biceps repair.76 It has been shown in animal studies that tendons heal to cortical bone without the need to create a cancellous socket/trough.85,88 Further, a clinical study using postoperative magnetic resonance imaging (MRI) scans after a distal

Figure 6 The radial tuberosity can be exposed through an anterior approach with hypersupination (left) or posterior extensor carpi ulnaris/supinator muscle–splitting approach with maximum pronation (right). BR, brachioradialis m.; EDC, extensor digitorum communis m.; ECU, extensor carpi ulnaris m.; A, anconeus m.; S, supinator m.; FCU, flexor carpi ulnaris m.; PT, pronator teres m. (From Schmidt CC, Brown BT, Qvick LM, Stachowicz RZ, Latona CR, Miller MC. Factors that determine supination strength following distal biceps repair. J Bone Joint Surg 2016;98:1153-60. Reprinted with permission from Journal of Bone and Joint Surgery, Inc.)

ARTICLE IN PRESS Distal biceps tendon an anatomic footprint repair with or without current suture devices.27,43

Diagnosis Patients commonly report a history of an eccentric elbow flexion, traumatic pop, ecchymosis, and pain. Physical examination reveals weak supination and flexion strength compared with the uninjured side. If the lacertus fibrosus is also torn, the biceps muscle is seen to retract proximal; this is called a reverse Popeye sign. Myotendinous junction tears, albeit rare, can also present with antecubital pain, ecchymosis, swelling, or weakness with elbow flexion and supination.73 The hook test is useful in differentiating between a complete avulsion and an incomplete injury such as a sprain, partial rupture, or myotendinous junction tear.64 The test is reported to be 100% sensitive and 100% specific in detecting complete distal ruptures; it is based on the fact that an attached biceps tendon feels like a tight cord with isometric supination.64 If doubt still remains, an elbow ultrasound scan or MRI can aid in the diagnosis.

Nonoperative treatment A functioning biceps muscle is a prerequisite for supination strength through a full arc of rotation and normal rotational kinematics.75 Without a working biceps, supination torque, power, and endurance are dependent solely on the brachioradialis and supinator muscles.75 The brachioradialis muscle is a strong supinator from a pronated to neutral position but becomes a forearm pronator from neutral to terminal supination; the supinator muscle’s moment arm declines between neutral and supination, so it is not designed to compensate for a missing biceps muscle.75 Strength curves of chronic biceps-deficient arms illustrate this profound deficiency between neutral and terminal supination75 (Fig. 7, A). Patients can adapt to the biceps loss by pinching their arm in adduction against their chest, locking the forearm in neutral, and rotating with their trunk.57,75 The real loss comes when they have to supinate away from their body to perform a task (eg, changing a light bulb) because the act of reaching eliminates the supporting trunk. The Disabilities of the Arm, Shoulder, and Hand (DASH) score does not measure the functional loss after a biceps rupture. In a retrospective study looking at nonoperative treatment, the average reported DASH score was 14 (normative for the U.S. population is 10.1), but 38% (6/16) of the patients reported weakness turning a screw driver and 50% (8/ 16) reported difficulty lifting heavy objects.28,39 A recent clinical study reported an average 30% loss in flexion peak torque and 50% loss in supination peak torque; further, the threshold to fatigue with repetitive supination was markedly reduced because the injured arm started the activity at a lower initial peak torque.62 Some patients seem to accept and adjust to their strength loss, but their kinematics definitely change, and this does affect their performance.5,28,60,75

5

Operative treatment Surgical reattachment of acute and chronic ruptures results in high patient satisfaction, low pain levels, and good to excellent outcomes with either anterior or posterior approaches regardless of fixation techniques.1,4-6,14-16,18-20,23,24,26,30,31,34,35,37,44,45,49,50,52,56,60,65,66,77,86,90,94 The DASH scores following repair range from 3.6 to 14.5, indicating a low level of disability.15,39,49,77,94 Despite this apparent efficacy, a number of comprehensive studies show a significant postoperative supination strength loss and supination work deficit, suggesting that there is room for improvement.1,14,15,18-20,34,45,49,50,77,86 Debating the following questions can improve our understanding of the current state of distal biceps treatment and spawn future improvements.

Are anatomic repairs clinically relevant? Pro—Christopher C. Schmidt, MD The 3 key components of an anatomic repair are (1) to replicate the external rotation of the tendon, (2) to restore the native attachment site for both the short and long heads, and (3) to preserve radial skeletal anatomy76,79 (Fig. 8). Most distal biceps repair papers report good to excellent patient satisfaction and return of contralateral strength in a neutral position. There are only a handful of studies that quantified the tendon reattachment location and measured strength in positions other than neutral.34,74,77 Yet the reattachment position has been shown to be the most important factor in determining postoperative supination strength.69,74,80 In addition, our forearms function in positions other than neutral, so why limit testing to neutral?72 A critical review of our literature does show that there is a functional cost associated with a nonanatomic repair.18,34,65,74 In a retrospective anterior repair study, postoperative MRI quantified the biceps reattachment site as 73° more anterior than the native footprint; the authors thought this anterior position was responsible for the measured postoperative decrease in supination strength, 10% in neutral (P = .051) and 33% in 60° of supination (P < .010)77 (Fig. 7, B). Another study using postoperative computed tomography scans reported an average suture anchor placement 50° anterior to the apex, a nonanatomic reattachment site.34 They reported an interesting finding that the mean DASH score was 10 ± 7 (normative, 10.2), but 47% (9/21) of the patients reported some difficulty in returning to the same physical activity because of weakness, fatigue, and wrist rotation problems.34 Further, there were significant (P < .016) differences in supination strength at angles of 10° (85% ± 20%), 45° (80% ± 22%), and 80° (82% ± 21%) compared with the uninjured arm; work was 66% to 75% less than the uninjured arm (P < .05).34 The measured loss in supination strength in both studies can be attributed to nonanatomic repairs causing premature unwinding of the distal tendon and the loss of the cam effect of the radial tuberosity.76,77,80 A posterior repair group, compared with an anterior group, restored the footprint to an anatomic position

ARTICLE IN PRESS 6

C.C. Schmidt et al.

Figure 7 Supination strength curves for nonoperative treatment (A), anterior nonanatomic biceps repair (B), and posterior anatomic biceps repair (C). (A) The strength curves from a group of conservatively treated patients (no repair). The blue line represents the initial (<4 weeks) strength loss; the red line depicts the strength gained with >2 years of conservative treatment. Notice the profound loss of supination strength between neutral and supinated forearm positions (hatched area). The blue dashed line is the normalized uninjured arm. (B) The supination strength gained with a biceps repair using an anterior nonanatomic repair (yellow line). A 33% weakness in a forearm supinated position. (C) The supination strength gained with a biceps repair using a posterior anatomic repair. The posterior anatomic repair group was 14% stronger (green line) than the anterior nonanatomic group in a supinated forearm position. The blue shaded area represents the estimated gain in supination strength from neutral to full supination using a posterior repair. Note that despite an anatomic repair, the strength does not fully recover to preoperative levels, which is represented by the hatched area. (Supination strength curves were derived from studies performed between 2012 and 2015; strength relationships have been interpolated between data points.74,75,77 Nonanatomic and anatomic repairs were verified with postoperative magnetic resonance imaging scans. The x-axis is the forearm position and y-axis the supination strength normalized to that of an uninjured side.)

ARTICLE IN PRESS Distal biceps tendon

7

Figure 8 Illustration and pictures of the anatomic distal biceps repair. (A) Two drill holes are positioned in the centroid of the long and short head insertion sites on the radial tuberosity. (B) The completed anatomic repair. (C) A schematic of the anatomic repair illustrating 2 intramedullary cortical buttons used for tendon fixation. (D) An axial picture of the repair illustrating preservation of the protuberance of the radial tuberosity. LH, long head; SH, short head; A, anterior to biceps footprint; P, posterior to biceps footprint. (From Schmidt CC, Brown BT, Williams BG, Rubright JH, Schmidt DL, Pic AC, et al. The importance of preserving the radial tuberosity during distal biceps repair. J Bone Joint Surg Am 2015;97:2014-23. Reprinted with permission from Journal of Bone and Joint Surgery, Inc.; and Schmidt CC, Jarrett CD, Brown BT. The distal biceps tendon. J Hand Surg Am 2013;38:811-21. Reprinted with permission from Elsevier.)

and returned 14% greater supination strength in 60° of supination (P = .027)74 (Fig. 7, C). Even in studies that do not measure repair position, patients still perceive a loss of function after their repair. An anterior approach cohort study comparing cortical button and interference screw to suture anchor repair reported no difference in strength in neutral or complications between the groups. There was however a perception of weakness which occurred in 20% (4/20) in the cortical button and interference screw group, as well as 53% (9/17) in the suture anchor group.65 Others have reported that this sense of weakness was failure to recover total work performed during repetitive supination exercises.18 An anatomic reattachment site has been statistically (P < .0001) correlated to return of strength equal to that of the uninjured arm through a physiologic range of forearm motion.74 The biceps tendon is the main forearm supinator, so why compromise its function by repairing it anterior to its native insertion site? Why leave your patients weak? Some patients may unconsciously adapt to their weakness by locking the forearm and supinating with their shoulder. This adaptive kinematic change may accomplish the supination tasks, but at a cost of decreased performance. To maximize supination efficiency during activities of life like turning a screwdriver, dead bolt, or light bulb and swinging a golf club

or baseball bat, an anatomic footprint repair should be the surgical goal.

Con—Felix (Buddie) H. Savoie III, MD We live in a right-handed world and a biceps tendon attachment a few millimeters anterior to the insertion in a nondominant arm really does not matter. I am not so sure a footprint reattachment is needed even in the dominant arm. There are no level I or II studies that have shown that a footprint repair with tuberosity preservation leads to better clinical outcomes or strength. Terminal supination torque is needed in only a few overhead tasks (eg, changing a light bulb), where the arm cannot be pinned to the trunk. How often does that occur? Our group has reported good clinical success using an anterior approach and repairing the ruptured biceps to the tuberosity with either suture anchors or cortical button and interference screw.37,44 The reattachment position in our studies was not quantified, but based on my experience, a majority of these repairs were anatomic. In the worst case scenario, the reattachment sites were a few millimeters anterior to the native footprint.34,37,43,44 Yet, the Andrews-Carson outcome scores (minimum score, 30; maximum, 200) statistically (P < .001) improved from a preoperative average of 168 to

ARTICLE IN PRESS 8

C.C. Schmidt et al.

a postoperative average of 196; postoperatively, 91% (29/ 32) scores were excellent, 9% (2/32) good, and 1/32 fair.37 Manual supination testing showed that 88% (28/32) had 5/5 strength and 12% (4/32) 4/5.37 All 31 patients (32 elbows) were continuing their previous activity level or employment without difficulty.37 I am just not sure that the extra supination strength gained (14%) with an anatomic approach is clinically meaningful74 (Fig. 7, C).

Does a posterior approach compared with an anterior approach provide superior outcomes with fewer complications? Pro—Scott P. Steinmann, MD, and Michael Hausman, MD The posterior approach consistently provides the necessary exposure for an anatomic repair.15,35,43,54,74,94 It is nearly impossible for an anatomic biceps reattachment through an anterior approach because of the bulky flexor/pronator muscle mass and the rotational orientation of the radial tuberosity.27,34,36,43,74,77 Mechanical and clinical studies have shown increased supination torque with an anatomic biceps reattachment15,69,74,80,94 (Fig. 7, C). Neurovascular injury is less with a posterior compared with an anterior approach.12,15,16 An anterior approach has been associated with a number of the nerve injuries that were caused by prolonged retraction against the brachioradialis muscle placing concentrated pressure on the posterior interosseous nerve (PIN) and lateral antebrachial cutaneous nerve palsies.16,31 A levered retractor, Hohlman, should not be placed along the neck of the radial tuberosity; instead, direct-pull retractors, Army-Navy, should be used during exposure (Fig. 9). A prospective randomized clinical trial did show a significant (P < .001) increase in the occurrence of lateral antebrachial cutaneous nerve palsies when using an anterior approach, 40% (19/47), relative to a posterior approach, 7% (3/43).31 Permanent PIN injuries have been reported with use of an anterior approach and an extramedullary button technique; the PIN is protected by supinating the forearm and directing the guide pin in an ulnar/proximal direction, not in a distal, radial, or distal-radial direction, or simply using an intramedullary button.4,12,30,53,70,74,83 Vascular injury using a posterior approach has not been reported. However, a case series on an anterior approach reported 1 (1/198) brachial artery injury requiring intraoperative thrombectomy.16 Symptomatic HO formation is a rare occurrence with a posterior approach.15,46 This can be attributed to avoidance of the ulna and medical prophylaxis.24,31 The ulna is avoided by splitting the ECU muscle or working in the ECU/EDC interval to expose the supinator muscle, which is also separated to expose the radial tuberosity. The ECU/EDC interval is easily identified by septocutaneous perforating vessels.58 In a prospective cohort study comparing anterior to posterior approaches, the patients were given indomethacin 25 mg 3 times a day and misoprostol 200 mcg twice a day for 2 weeks.24 There was 1 patient (1/9) in the anterior group who formed motion-limiting HO compared with none (0/10) in

Figure 9 (A) A patient 6 weeks after anterior biceps repair with a posterior interosseous nerve palsy. (B) Intraoperative findings show a damaged nerve from overzealous retraction. A levered retractor, Hohlman, should not be placed along the anterior neck of the radial tuberosity.

the posterior group.24 A randomized trial reported no statistical difference (P = .7) in HO formation between the groups (anterior, 2% (1/47) mild HO; posterior, 2% (1/43) mild HO) using indomethacin 25 mg 3 times daily for 3 weeks postoperatively in both groups.31 Other considerations that may favor a posterior approach are cosmesis and tendon rerupture rates. We have found that our limited horizontal anterior incisions resulted in less hypertrophic scarring and tendon adhesions compared with a traditional anterior approach, which crosses the elbow flexion crease.15,35 Further, the rerupture rate using a posterior approach is 1.7% (3/172), comparable to an anterior approach, 1.0% (2/198).16,38 We acknowledge that initial fixation strength plays a role in the rerupture rate; it is also low across all fixation techniques, and no one method has been found better than another.16,31,38,65 So, tendon fixation devices may not be clinically superior to simply attaching the tendon with drill holes and strong suture. Con—Ilya Voloshin, MD The anterior approach is elegant in that it uses an internervous plane between the radial innervated brachioradialis and median innervated pronator teres muscles. During the approach, care is taken to ligate the recurrent radial vessels traversing perpendicular to the arm’s long axis and lying ventral to the radial tuberosity.96 The supinator muscle is spared injury. During a posterior approach, the supinator muscle is split, and this

ARTICLE IN PRESS Distal biceps tendon

9

Figure 10 (A) A patient 4 months after a left-sided distal biceps rupture. The left biceps is proximally retracted, reverse Popeye sign. (B) Surprisingly, the atrophic tendon held sutures. (C) Muscle and tendon were mobilized and repaired in 70° of flexion. (D) Six weeks after repair, full extension is restored with an intact biceps tendon.

has been correlated to muscle fatty infiltration and terminal supinator weakness.74 Clinical success has been universally reported with an anterior approach, but as noted before, we have noted a high proportion of our patients reporting a perception of weakness despite a successful reattachment.65 Alternative techniques use the anterior approach, but they reattach the tendon posterior to the tuberosity to ensure normal tendon wrapping and preservation of the tuberosity’s cam effect.68,76,80,90 In theory, these techniques allow an anatomic repair through an anterior approach and thereby avoid iatrogenic supinator muscle injury. However, further studies that verify tendon reattachment position and rigorous strength and kinematic testing are required to prove this hypothesis.

Are chronic (>2 months) repairs in high flexion (>70°) better than tendon augmentation? Pro—Bernard F. Morrey, MD The management of chronic biceps tears has undergone a paradigm shift from favoring graft reconstruction to preferring high-flexion repairs.9,61,71 Chronic ruptures typically present with stiff, proximally contracted biceps muscle, shortened atrophic tendon, and abundant scar tissue. Traditional wisdom that high-flexion repairs lead to an increase in reruptures and flexion contractures has proved to be false.9,61 In a retrospective study comparing 23 patients repaired in >60° (range, 60°-90°) to 23 patients repaired in <30° (range, 0°-30°) using the same operative technique, we observed no clinical differences in

rerupture rates, range of elbow and forearm motion, pain, strength, or complications.61 An interesting observation was that the only rerupture occurred at the myotendinous junction after an early traumatic injury, implying that the weakest link in the repair was not the bone-tendon junction.61 Other investigators have reported clinical success with fixing chronic tears in high flexion (80°-110°) without flexion contractures or reruptures and a DASH score of 3.3 (10.1 normative).9 We no longer base the need for reconstruction on the amount of proximal retraction but on the quality of the myotendinous junction, the capacity of tendon to hold sutures, and the ability to mobilize the tendon sufficiently to be repaired to the tuberosity in 90° of flexion. For example, in case 1, the patient had a contracted muscle and shortened tendon, but the myotendinous junction was stable and the tendon held sutures (Fig. 10, A). The repair was completed in 70° of flexion, and 6 weeks after the repair, the patient had full extension (Fig. 10, B, C and D). In case 2, the myotendinous junction was poor quality and ruptured with simple traction placed on the distal sutures, so tendon augmentation was required (Fig. 11). The decision for a high-flexion repair vs. tendon augmentation needs to be made in the operating room once the quality of the myotendinous junction and tendon has been assessed; therefore, we recommend consenting patients for both repair and tendon augmentation preoperatively. High-flexion repairs are definitely easier with a posterior vs. an anterior approach because elbow flexion reduces the tendon and eliminates knot tying in the restricted space of the anterior elbow.

ARTICLE IN PRESS 10

C.C. Schmidt et al.

Figure 11 (A) A poor-quality tendon and a weakened myotendinous junction. (B) The biceps ruptured at the myotendinous junction during mobilization. (C) A tendon augmentation was required to restore biceps function.

Con—Dean G. Sotereanos, MD Tendon augmentation is a successful treatment for the chronic atrophic distal biceps rupture.17,32,33,51,71,84,91,95 There is no consensus on the definition of chronic. Is it 3 weeks or 4 months? The lack of agreement on the time frame is most likely due to healing/scarring variations among our patients, possibly genetics. So, time is a poor predictor of specific treatment. Our criteria for graft reconstruction are the following: (1) a poor-quality tendon (not able to hold sutures), (2) tendon length <4 cm (normal length, 4.2 cm), (3) significant proximal biceps contraction (lacertus fibrosus rupture), and (4) inability to repair the tendon in 70° of flexion. Using an anterior approach, Achilles tendon allograft, and suture anchors, we reported on a series of 7 patients with an average follow-up of 29 months.17 All patients were pain free at rest, but 1 experienced pain with strenuous activities; 6 of 7 patients recovered full extension (1/7 with a deficit of 20°), mean maximal supination torque was 87% (range, 65%-118%), but 1 patient complained of rotational weakness, and all patients returned to work.17 Overall, our patients thought that the surgery improved the quality of their lives. An alternative technique is to suture the graft to the biceps muscle and to use a posterior approach to secure it to the radial tuberosity.71,95 One of the keys to lessening the reverse Popeye deformity and improving supination strength is to tension the graft in high flexion between 70° and 90°.17,32,78 We do not advocate tendon augmentation for cosmetic appearance alone but reserve it for the irreparable biceps rupture in patients with chronic muscle cramping and disabling functional weakness.

The future Our current outcome tools (eg, DASH) that have been used to measure patient-perceived function could underestimate the disability after biceps rupture and treatment. For example, an anterior repair study reported an average postoperative DASH score of 10 (10.1 is normative for the U.S. population), but 47% of the patients noted troubles performing some physical activities because of weakness, fatigue, and rotational

difficulties.34,39 Elbow- or even biceps-specific outcome scores and task-driven isotonic testing are required to accurately quantify this perceived functional loss and the kinematic adaptations that may occur. It has been shown that restoration of supination strength has been positively correlated to a footprint reattachment, preservation of the proximal radial topography, and avoidance of iatrogenic supinator muscle damage.74,76 This additional strength may or may not be clinically relevant. Currently, no repair technique recovers supination strength through a full arc of supination (Fig. 7, C). Return of strength through full rotation seems important because a functional forearm arc occurs between 20° ± 18° of pronation and 104° ± 10° of supination.72 Endoscopically assisted repair techniques are a strategy to return supination strength by ensuring footprint restoration while minimizing iatrogenic supinator muscle damage. Analogous to open repairs, the scope can be positioned thorough either an anterior or posterior portal. The anterior approach uses the endoscope to repair the tendon posterior to the native footprint, which is a similar technique to a previously published repair.68,90 Two of the authors (C.C.S. and S.P.S.) are currently developing a posterior supinatorpreserving endoscope-assisted technique reattaching the short and long heads to their respective anatomic footprints (Fig. 12). Future prospective studies will be required to elucidate the merits and safety of these endoscope-assisted repair techniques. Rehabilitation programs vary widely after distal biceps repair. Recent literature suggests that the rate of rerupture for acute (5.1%) and chronic (7.0%) repairs may be higher than previously published.93 Multicenter randomized studies comparing immediate active motion to limited protective bracing programs are required for us to understand their effect on outcome and complication rates.

Conclusion The biceps complex has been thought of as 2 muscles coalescing into 1 distal insertion; however, several anatomic

ARTICLE IN PRESS Distal biceps tendon

11

Figure 12 Pictures of endoscope-assisted posterior supinator-preserving anatomic repair performed by one of the authors (C.C.S.). (A) Torn tendon was shaved off the footprint, and short and long head drill holes were made in the perceived centroids. (B) Cortical buttons were inserted into the drill holes. (C) The short and long heads were tied down to their native footprints using standard arthroscopic knottying tools. (D) Intraoperative image showing the endoscope and confirming drill holes and button positions.

and mechanical studies have found that this is not the case. The distal biceps tendon consists of short head and long head subunits. Inaccurate placement of the tendon on the proximal radius or creating a tuberosity trough during surgical reattachment has been shown to result in alterations in the biceps’ mechanics, and these nonanatomic repair techniques have the potential to compromise clinical results. Nonanatomic reattachment of a ruptured biceps can lead to a sense of rotational weakness and measured supination strength loss. Some patients are able to adapt to this strength loss without a considerable lifestyle change, whereas others believe it hinders their performance. It can be difficult to anatomically repair the biceps footprint through an anterior approach, but a posterior approach can damage the supinator muscle, both compromising postoperative strength. The ideal repair restores the native footprint without disturbing the proximal radial geometry and injuring the supinator muscle. With medical prophylaxis, there appears to be no difference between the anterior and posterior approaches in the occurrence of motion-limiting HO. Primarily repairing the chronic torn biceps in high flexion may decrease the need for tendon augmentation. If tendon augmentation is required, tensioning the repair between 70° and 90° of flexion may improve results. Endoscopically assisted repairs limit supination muscle damage while ensuring that a footprint repair may be the preferred future repair technique.

Disclaimer Christopher C. Schmidt: Arthrex, Inc: paid consultant. Felix H. Savoie III: American Shoulder and Elbow Surgeons: Board or committee member; Arthroscopy: Editorial or governing board; Arthroscopy Association of North America: Board or committee member; Biomet: unpaid consultant; Exactech, Inc: IP royalties, unpaid consultant; Journal of Wrist Surgery: Editorial or governing board; Mitek: paid presenter or speaker, research support, unpaid consultant; Rotation Medical: unpaid consultant; Smith & Nephew: paid presenter or speaker, unpaid consultant. Scott P. Steinmann: Acumed, LLC: paid consultant; American Shoulder and Elbow Surgeons: Board or committee member; American Society for Surgery of the Hand: Board or committee member; Arthrex, Inc: IP royalties, paid consultant; Articulinx: paid consultant; Biomet: IP royalties, paid consultant; Elsevier: paid consultant; IMDS: IP royalties; Journal of Hand Surgery (American Volume): Editorial or governing board; Journal of Shoulder and Elbow Surgery: Editorial or governing board; Orthopedics Today: Editorial or governing board. Michael Hausman: Checkpoint Surgical, NDI Medical, SPR Therapeutics: stock or stock options, unpaid consultant; Flower Orthopedics, unpaid consultant; Smith & Nephew: IP royalties; Stryker: paid consultant; Trimed: paid presenter or speaker.

ARTICLE IN PRESS 12 Ilya Voloshin: American Shoulder and Elbow Surgeons: Board or committee member; Arthrex, Inc: paid consultant, research support; Arthroscopy Association of North America: Board or committee member; Zimmer: paid consultant. Bernard F. Morrey: Personal fees from employment ; nonfinancial support from expert testimony; grants from Grants Pending; payment for lectures including service on speakers bureaus, personal fees from royalties, personal fees from stock options outside the submitted work. Dean G. Sotereanos: Arthrex, Inc: paid consultant; AxoGen Inc: paid consultant; Smith & Nephew: paid consultant. The other authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

References 1. Agins HJ, Chess JL, Hoekstra DV, Teitge RA. Rupture of the distal insertion of the biceps brachii tendon. Clin Orthop Relat Res 1988;234:34-8. 2. Agrawal V, Stinson MJ. Case report: heterotopic ossification after repair of distal biceps tendon rupture utilizing a single-incision Endobutton technique. J Shoulder Elbow Surg 2005;14:107-9. http://dx.doi.org/ 10.1016/j.jse.2004.03.014 3. Athwal GS, Steinmann SP, Rispoli DM. The distal biceps tendon: footprint and relevant clinical anatomy. J Hand Surg Am 2007;32:1225-9. http://dx.doi.org/10.1016/j.jhsa.2007.05.027 4. Bain GI, Prem H, Heptinstall RJ, Verhellen R, Paix D. Repair of distal biceps tendon rupture: a new technique using the Endobutton. J Shoulder Elbow Surg 2000;9:120-6. 5. Baker BE, Bierwagen D. Rupture of the distal tendon of the biceps brachii. Operative versus non-operative treatment. J Bone Joint Surg Am 1985;67:414-7. 6. Barnes SJ, Coleman SG, Gilpin D. Repair of avulsed insertion of biceps. A new technique in four cases. J Bone Joint Surg Br 1993;75:938-9. 7. Berlet GC, Johnson JA, Milne AD, Patterson SD, King GJ. Distal biceps brachii tendon repair. An in vitro biomechanical study of tendon reattachment. Am J Sports Med 1998;26:428-32. 8. Bisson L, Moyer M, Lanighan K, Marzo J. Complications associated with repair of a distal biceps rupture using the modified two-incision technique. J Shoulder Elbow Surg 2008;17:67S-71S. http://dx.doi.org/ 10.1016/j.jse.2007.04.008 9. Bosman HA, Fincher M, Saw N. Anatomic direct repair of chronic distal biceps brachii tendon rupture without interposition graft. J Shoulder Elbow Surg 2012;21:1342-7. http://dx.doi.org/10.1016/j.jse.2012.01.012 10. Boucher PR, Morton KS. Rupture of the distal biceps brachii tendon. J Trauma 1967;7:626-32. 11. Boyd HB, Anderson LD. A method for reinsertion of the distal biceps brachii tendon. J Bone Joint Surg 1961;43:1041-3. 12. Cain RA, Nydick JA, Stein MI, Williams BD, Polikandriotis JA, Hess AV. Complications following distal biceps repair. J Hand Surg Am 2012;37:2112-7. http://dx.doi.org/10.1016/j.jhsa.2012.06.022 13. Carroll RE, Hamilton LR. Rupture of biceps brachii—a conservative method of treatment. J Bone Joint Surg Am 1967;49:1016. 14. Cheung EV, Lazarus M, Taranta M. Immediate range of motion after distal biceps tendon repair. J Shoulder Elbow Surg 2005;14:516-8. http://dx.doi.org/10.1016/j.jse.2004.12.003

C.C. Schmidt et al. 15. Cil A, Merten S, Steinmann SP. Immediate active range of motion after modified 2-incision repair in acute distal biceps tendon rupture. Am J Sports Med 2009;37:130-5. http://dx.doi.org/10.1177/0363546508323749 16. Cusick MC, Cottrell BJ, Cain RA, Mighell MA. Low incidence of tendon rerupture after distal biceps repair by cortical button and interference screw. J Shoulder Elbow Surg 2014;23:1532-6. http://dx.doi.org/ 10.1016/j.jse.2014.04.013 17. Darlis NA, Sotereanos DG. Distal biceps tendon reconstruction in chronic ruptures. J Shoulder Elbow Surg 2006;15:614-9. http://dx.doi.org/ 10.1016/j.jse.2005.10.004 18. Davison BL, Engber WD, Tigert LJ. Long term evaluation of repaired distal biceps brachii tendon ruptures. Clin Orthop Relat Res 1996;333:186-91. 19. D’Alessandro DF, Shields CL Jr, Tibone JE, Chandler RW. Repair of distal biceps tendon ruptures in athletes. Am J Sports Med 1993;21:1149. 20. D’Arco P, Sitler M, Kelly J, Moyer R, Marchetto P, Kimura I, 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 Sports Med 1998;26:254-61. 21. Dobbie RP. Avulsion of lower biceps brachii tendon: analysis of fifty-one previously unreported cases. Am J Surg 1941;51:21. 22. Eames MH, Bain GI, Fogg QA, van Riet RP. Distal biceps tendon anatomy: a cadaveric study. J Bone Joint Surg Am 2007;89:1044-9. http://dx.doi.org/10.2106/JBJS.D.02992 23. Eardley WG, Odak S, Adesina TS, Jeavons RP, McVie JL. Bioabsorbable interference screw fixation of distal biceps ruptures through a single anterior incision: a single-surgeon case series and review of the literature. Arch Orthop Trauma Surg 2010;130:875-81. http://dx.doi.org/10.1007/ s00402-009-0974-x 24. El-Hawary R, Macdermid JC, Faber KJ, Patterson SD, King GJ. Distal biceps tendon repair: comparison of surgical techniques. J Hand Surg Am 2003;28:496-502. http://dx.doi.org/10.1053/jhsu.2003.50081 25. Failla JM, Amadio PC, Morrey BF, Beckenbaugh RD. Proximal radioulnar synostosis after repair of distal biceps brachii rupture by the two-incision technique. Report of four cases. Clin Orthop Relat Res 1990;253:133-6. 26. Fenton P, Qureshi F, Ali A, Potter D. Distal biceps tendon rupture: a new repair technique in 14 patients using the biotenodesis screw. Am J Sports Med 2009;37:2009-15. http://dx.doi.org/10.1177/ 0363546509335465 27. Forthman CL, Zimmerman RM, Sullivan MJ, Gabel GT. Cross-sectional anatomy of the bicipital tuberosity and biceps brachii tendon insertion: relevance to anatomic tendon repair. J Shoulder Elbow Surg 2008;17:522-6. http://dx.doi.org/10.1016/j.jse.2007.11.002 28. Freeman CR, McCormick KR, Mahoney D, Baratz M, Lubahn JD. Nonoperative treatment of distal biceps tendon ruptures compared with a historical control group. J Bone Joint Surg Am 2009;91:2329-34. http://dx.doi.org/10.2106/JBJS.H.01150 29. Friedmann E. Rupture of the distal biceps brachii tendon. JAMA 1963;184:60. 30. Greenberg JA, Fernandez JJ, Wang T, Turner C. EndoButton-assisted repair of distal biceps tendon ruptures. J Shoulder Elbow Surg 2003;12:484-90. http://dx.doi.org/10.1016/s1058-2746(03)00173-3 31. Grewal R, Athwal GS, MacDermid JC, Faber KJ, Drosdowech DS, El-Hawary R, 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;94:1166-74. http://dx.doi.org/10.2106/JBJS.K.00436 32. Hallam P, Bain GI. Repair of chronic distal biceps tendon ruptures using autologous hamstring graft and the Endobutton. J Shoulder Elbow Surg 2004;13:648-51. http://dx.doi.org/10.1016/j.jse.2004.01.032 33. Hang DW, Bach BR, Bojchuk J. Repair of chronic distal biceps brachii tendon rupture using free autogenous semitendinosus tendon. Clin Orthop Relat Res 1996;323:188-91. 34. Hansen G, Smith A, Pollock JW, Werier J, Nairn R, Rakhra KS, et al. Anatomic repair of the distal biceps tendon cannot be consistently performed through a classic single-incision suture anchor technique.

ARTICLE IN PRESS Distal biceps tendon

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45. 46.

47.

48.

49.

50.

51.

52.

53.

J Shoulder Elbow Surg 2014;23:1898-904. http://dx.doi.org/10.1016/ j.jse.2014.06.051 Hartman MW, Merten SM, Steinmann SP. Mini-open 2-incision technique for repair of distal biceps tendon ruptures. J Shoulder Elbow Surg 2007;16:616-20. http://dx.doi.org/10.1016/j.jse.2006.10.021 Hasan SA, Cordell CL, Rauls RB, Bailey MS, Sahu D, Suva LJ. Two-incision versus one-incision repair for distal biceps tendon rupture: a cadaveric study. J Shoulder Elbow Surg 2012;21:935-41. http:// dx.doi.org/10.1016/j.jse.2011.04.027 Heinzelmann AD, Savoie FH 3rd, Ramsey JR, Field LD, Mazzocca AD. A combined technique for distal biceps repair using a soft tissue button and biotenodesis interference screw. Am J Sports Med 2009;37:989-94. http://dx.doi.org/10.1177/0363546508330130 Hinchey JW, Aronowitz JG, Sanchez-Sotelo J, Morrey BF. Re-rupture rate of primarily repaired distal biceps tendon injuries. J Shoulder Elbow Surg 2014;23:850-4. http://dx.doi.org/10.1016/j.jse.2014.02.006 Hunsaker FG, Cioffi DA, Amadio PC, Wright JG, Caughlin B. The American Academy of Orthopaedic Surgeons outcomes instruments: normative values from the general population. J Bone Joint Surg Am 2002;84-A:208-15. Hutchinson HL, Gloystein D, Gillespie M. Distal biceps tendon insertion: an anatomic study. J Shoulder Elbow Surg 2008;17:342-6. http:// dx.doi.org/10.1016/j.jse.2007.05.005 Idler CS, Montgomery WH 3rd, Lindsey DP, Badua PA, Wynne GF, Yerby SA. Distal biceps tendon repair: a biomechanical comparison of intact tendon and 2 repair techniques. Am J Sports Med 2006;34:968-74. http://dx.doi.org/10.1177/0363546505284185 Jarrett CD, Weir DM, Stuffmann ES, Jain S, Miller MC, Schmidt CC. Anatomic and biomechanical analysis of the short and long head components of the distal biceps tendon. J Shoulder Elbow Surg 2012;21:942-8. http://dx.doi.org/10.1016/j.jse.2011.04.030 Jobin CM, Kippe MA, Gardner TR, Levine WN, Ahmad CS. Distal biceps tendon repair: a cadaveric analysis of suture anchor and interference screw restoration of the anatomic footprint. Am J Sports Med 2009;37:2214-21. http://dx.doi.org/10.1177/0363546509337451 John CK, Field LD, Weiss KS, Savoie FH 3rd. Single-incision repair of acute distal biceps ruptures by use of suture anchors. J Shoulder Elbow Surg 2007;16:78-83. http://dx.doi.org/10.1016/j.jse.2006.03.002 Karunakar MA, Cha P, Stern PJ. Distal biceps ruptures. A followup of Boyd and Anderson repair. Clin Orthop Relat Res 1999;363:100-7. 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-A:1575-81. Kettler M, Lunger J, Kuhn V, Mutschler W, Tingart MJ. Failure strengths in distal biceps tendon repair. Am J Sports Med 2007;35:1544-8. http://dx.doi.org/10.1177/0363546507300690 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;90:103-6. http://dx.doi.org/10.1302/0301 -620x.90b1.19285 Khan AD, Penna S, Yin Q, Sinopidis C, Brownson P, Frostick SP. Repair of distal biceps tendon ruptures using suture anchors through a single anterior incision. Arthroscopy 2008;24:39-45. http://dx.doi.org/10.1016/ j.arthro.2007.06.019 Leighton MM, Bush-Joseph CA, Bach BR Jr. Distal biceps brachii repair. Results in dominant and nondominant extremities. Clin Orthop Relat Res 1995;317:114-21. Levy HJ, Mashoof AA, Morgan D. Repair of chronic ruptures of the distal biceps tendon using flexor carpi radialis tendon graft. Am J Sports Med 2000;28:538-40. Lintner S, Fischer T. Repair of the distal biceps tendon using suture anchors and an anterior approach. Clin Orthop Relat Res 1996;322:1169. Lo EY, Li CS, Van den Bogaerde JM. The effect of drill trajectory on proximity to the posterior interosseous nerve during cortical button distal biceps repair. Arthroscopy 2011;27:1048-54. http://dx.doi.org/10.1016/ j.arthro.2011.03.084

13 54. Lynch SA, Beard DM, Renstrom PA. Repair of distal biceps tendon rupture with suture anchors. Knee Surg Sports Traumatol Arthrosc 1999;7:125-31. 55. Mazzocca AD, Burton KJ, Romeo AA, Santangelo S, Adams DA, Arciero RA. Biomechanical evaluation of 4 techniques of distal biceps brachii tendon repair. Am J Sports Med 2007;35:252-8. http://dx.doi.org/ 10.1177/0363546506294854 56. McKee MD, Hirji R, Schemitsch EH, Wild LM, Waddell JP. Patientoriented functional outcome after repair of distal biceps tendon ruptures using a single-incision technique. J Shoulder Elbow Surg 2005;14:302-6. http://dx.doi.org/10.1016/j.jse.2004.09.007 57. Meherin JM, Kilgore ES. The treatment of ruptures of the distal biceps brachii tendon. Am J Surg 1960;99:636-40. 58. Miller SL, Hausman M. Distal biceps repair: a consistent and safe approach to the radial tuberosity. Orthopedics 2001;24:113-6. 59. Morrey BF. Tendon injuries about the elbow. In: Morrey BF, Sanchez-Sotelo J, editors. The elbow and its disorders. Philadelphia: WB Saunders; 1993. p. 492-504. 60. Morrey BF, Askew LJ, An KN, Dobyns JH. Rupture of the distal tendon of the biceps brachii. A biomechanical study. J Bone Joint Surg Am 1985;67:418-21. 61. Morrey ME, Abdel MP, Sanchez-Sotelo J, Morrey BF. Primary repair of retracted distal biceps tendon ruptures in extreme flexion. J Shoulder Elbow Surg 2014;23:679-85. http://dx.doi.org/10.1016/j.jse.2013.12.030 62. Nesterenko S, Domire ZJ, Morrey BF, Sanchez-Sotelo J. Elbow strength and endurance in patients with a ruptured distal biceps tendon. J Shoulder Elbow Surg 2010;19:184-9. http://dx.doi.org/10.1016/j.jse.2009.06 .001 63. Nigro PT, Cain R, Mighell MA. Prognosis for recovery of posterior interosseous nerve palsy after distal biceps repair. J Shoulder Elbow Surg 2013;22:70-3. http://dx.doi.org/10.1016/j.jse.2012.08.001 64. O’Driscoll SW, Goncalves LB, Dietz P. The hook test for distal biceps tendon avulsion. Am J Sports Med 2007;35:1865-9. http://dx.doi.org/ 10.1177/0363546507305016 65. Olsen JR, Shields E, Williams RB, Miller R, Maloney M, Voloshin I. A comparison of cortical button with interference screw versus suture anchor techniques for distal biceps brachii tendon repairs. J Shoulder Elbow Surg 2014;23:1607-11. http://dx.doi.org/10.1016/j.jse.2014.06 .049 66. Peeters T, Ching-Soon NG, Jansen N, Sneyers C, Declercq G, Verstreken F. Functional outcome after repair of distal biceps tendon ruptures using the endobutton technique. J Shoulder Elbow Surg 2009;18:283-7. http://dx.doi.org/10.1016/j.jse.2008.10.004 67. Pereira DS, Kvitne RS, Liang M, Giacobetti FB, Ebramzadeh E. Surgical repair of distal biceps tendon ruptures: a biomechanical comparison of two techniques. Am J Sports Med 2002;30:432-6. 68. Phadnis J, Bain G. Endoscopic-assisted distal biceps footprint repair. Tech Hand Up Extrem Surg 2015;19:55-9. http://dx.doi.org/10.1097/ BTH.0000000000000078 69. Prud’homme-Foster M, Louati H, Pollock JW, Papp S. Proper placement of the distal biceps tendon during repair improves supination strength—a biomechanical analysis. J Shoulder Elbow Surg 2015;24:527-32. http://dx.doi.org/10.1016/j.jse.2014.09.039 70. Saldua N, Carney J, Dewing C, Thompson M. The effect of drilling angle on posterior interosseous nerve safety during open and endoscopic anterior single-incision repair of the distal biceps tendon. Arthroscopy 2008;24:305-10. http://dx.doi.org/10.1016/j.arthro.2007.09.016 71. Sanchez-Sotelo J, Morrey BF, Adams RA, O’Driscoll SW. Reconstruction of chronic ruptures of the distal biceps tendon with use of an Achilles tendon allograft. J Bone Joint Surg Am 2002;84-A:9991005. 72. Sardelli M, Tashjian RZ, MacWilliams BA. Functional elbow range of motion for contemporary tasks. J Bone Joint Surg Am 2011;93:471-7. http://dx.doi.org/10.2106/jbjs.i.01633 73. Schamblin ML, Safran MR. Injury of the distal biceps at the musculotendinous junction. J Shoulder Elbow Surg 2007;16:208-12. http://dx.doi.org/10.1016/j.jse.2006.06.009

ARTICLE IN PRESS 14 74. Schmidt CC, Brown BT, Qvick LM, Stacowicz RZ, Latona CR, Miller MC. Factors that determine supination strength following distal biceps repair. J Bone Joint Surg Am 2016;98:1153-60. http://dx.doi.org/ 10.2106/JBJS.15.01025 75. Schmidt CC, Brown BT, Sawardeker PJ, DeGravelle M Jr, Miller MC. Factors affecting supination strength after a distal biceps rupture. J Shoulder Elbow Surg 2014;23:68-75. http://dx.doi.org/10.1016/ j.jse.2013.08.019 76. Schmidt CC, Brown BT, Williams BG, Rubright JH, Schmidt DL, Pic AC, et al. The importance of preserving the radial tuberosity during distal biceps repair. J Bone Joint Surg Am 2015;97:2014-23. http://dx.doi.org/ 10.2106/JBJS.N.01221 77. Schmidt CC, Diaz VA, Weir DM, Latona CR, Miller MC. Repaired distal biceps magnetic resonance imaging anatomy compared with outcome. J Shoulder Elbow Surg 2012;21:1623-31. http://dx.doi.org/10.1016/ j.jse.2012.03.009 78. Schmidt CC, Jarrett CD. Distal biceps tendon repair and reconstruction. In: Advanced reconstruction series: elbow. Chapter 9, 2nd ed. Rosemont, Illinois: American Academy of Orthopaedic Surgeons; 2016. 79. Schmidt CC, Jarrett CD, Brown BT. The distal biceps tendon. J Hand Surg Am 2013;38:811-21. http://dx.doi.org/10.1016/j.jhsa.2013.01.042 80. Schmidt CC, Weir DM, Wong AS, Howard M, Miller MC. The effect of biceps reattachment site. J Shoulder Elbow Surg 2010;19:1157-65. http://dx.doi.org/10.1016/j.jse.2010.05.027 81. Sethi P, Obopilwe E, Rincon L, Miller S, Mazzocca A. Biomechanical evaluation of distal biceps reconstruction with cortical button and interference screw fixation. J Shoulder Elbow Surg 2010;19:53-7. http://dx.doi.org/10.1016/j.jse.2009.05.007 82. Siebenlist S, Buchholz A, Zapf J, Sandmann GH, Braun KF, Martetschlager F, et al. Double intramedullary cortical button versus suture anchors for distal biceps tendon repair: a biomechanical comparison. Knee Surg Sports Traumatol Arthrosc 2015;23:926-33. http://dx.doi.org/10.1007/s00167-013-2590-0 83. Siebenlist S, Lenich A, Buchholz A, Martetschlager F, Eichhorn S, Heinrich P, et al. Biomechanical in vitro validation of intramedullary cortical button fixation for distal biceps tendon repair: a new technique. Am J Sports Med 2011;39:1762-8. http://dx.doi.org/10.1177/ 0363546511404139 84. Snir N, Hamula M, Wolfson T, Meislin R, Strauss EJ, Jazrawi LM. Clinical outcomes after chronic distal biceps reconstruction with allografts. Am J Sports Med 2013;41:2288-95. http://dx.doi.org/ 10.1177/0363546513502306

C.C. Schmidt et al. 85. Soda Y, Sumen Y, Murakami Y, Ikuta Y, Ochi M. Attachment of autogenous tendon graft to cortical bone is better than to cancellous bone: a mechanical and histological study of MCL reconstruction in rabbits. Acta Orthop Scand 2003;74:322-6. http://dx.doi.org/10.1080/ 00016470310014256 86. Sotereanos DG, Pierce TD, Varitimidis SE. A simplified method for repair of distal biceps tendon ruptures. J Shoulder Elbow Surg 2000;9:227-33. 87. Spang JT, Weinhold PS, Karas SG. A biomechanical comparison of EndoButton versus suture anchor repair of distal biceps tendon injuries. J Shoulder Elbow Surg 2006;15:509-14. http://dx.doi.org/10.1016/ j.jse.2005.09.020 88. St Pierre P, Olson EJ, Elliott JJ, O’Hair KC, McKinney LA, Ryan J. Tendon-healing to cortical bone compared with healing to a cancellous trough. A biomechanical and histological evaluation in goats. J Bone Joint Surg Am 1995;77:1858-66. 89. Strauch RJ, Rosenwasser MP. Single incision repair of distal biceps tendon rupture. Tech Hand Up Extrem Surg 1998;2:8. 90. Tanner C, Johnson T, Muradov P, Husak L. Single incision power optimizing cost-effective (SPOC) distal biceps repair. J Shoulder Elbow Surg 2013;22:305-11. http://dx.doi.org/10.1016/j.jse.2012.10.044 91. Vastamäki M, Vastamäki H. A simple grafting method to repair irreparable distal biceps tendon. Clin Orthop Relat Res 2008;466:247581. http://dx.doi.org/10.1007/s11999-008-0389-y 92. Vidal AF, Koonce RC, Wolcott M, Gonzales JB. Extensive heterotopic ossification after suspensory cortical fixation of acute distal biceps tendon ruptures. Arthroscopy 2012;28:1036-40. http://dx.doi.org/10.1016/ j.arthro.2012.03.025 93. Wang D, Joshi NB, Petrigliano FA, Cohen JR, Lord EL, Wang JC, et al. Trends associated with distal biceps tendon repair in the United States, 2007 to 2011. J Shoulder Elbow Surg 2016;25:676-80. http://dx.doi.org/ 10.1016/j.jse.2015.11.012 94. Weinstein DM, Ciccone WJ 2nd, Buckler MC, Balthrop PM, Busey TD, Elias JJ. Elbow function after repair of the distal biceps brachii tendon with a two-incision approach. J Shoulder Elbow Surg 2008;17:82S-86S. http://dx.doi.org/10.1016/j.jse.2007.07.006 95. Wiley WB, Noble JS, Dulaney TD, Bell RH, Noble DD. Late reconstruction of chronic distal biceps tendon ruptures with a semitendinosus autograft technique. J Shoulder Elbow Surg 2006;15:440-4. http://dx.doi.org/10.1016/j.jse.2005.08.018 96. Zeltser DW, Strauch RJ. Vascular anatomy relevant to distal biceps tendon repair. J Shoulder Elbow Surg 2016;25:283-8. http://dx.doi.org/ 10.1016/j.jse.2015.08.042