The American Journal of Sports Medicine http://ajs.sagepub.com/
Musculocutaneous Nerve Entrapment Hanley Ma, Ann Van Heest, Colleen Glisson and Shounuck Patel Am J Sports Med 2009 37: 2467 originally published online July 22, 2009 DOI: 10.1177/0363546509337406 The online version of this article can be found at: http://ajs.sagepub.com/content/37/12/2467
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Musculocutaneous Nerve Entrapment An Unusual Complication After Biceps Tenodesis Hanley Ma,* MD, Ann Van Heest,*† MD, Colleen Glisson,* MD, and Shounuck Patel,‡ MD From the *Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, ‡ Minnesota, and the Midwestern Chicago College of Osteopathic Medicine, Chicago, Illinois
Keywords: biceps tenodesis; complications; nerve injury; neurolysis
CASE REPORT
In the present case report, musculocutaneous nerve injury occurred with arthroscopic subacromial decompression, performed in association with arthroscopically assisted open biceps tenodesis. This report presents a case of musculocutaneous nerve injury as a rare complication after biceps tenodesis that can be effectively treated with neurolysis and tenodesis revision. Biceps tenodesis is often performed concomitantly with rotator cuff repairs. There is not an abundance of literature regarding the incidence and types of complications associated with biceps tenodesis. Boileau et al2 reported results of 68 biceps tenodesis patients and described a failure rate of 12%. Becker and Cofield1 presented a study of 51 patients who underwent tenodesis, and they observed a 12% complication rate, with 2 cases of reflex sympathetic dystrophy and 4 cases of postoperative adhesive capsulitis. In a description of biceps tenodesis, Neer4 recommends that during an acute repair of a rupture of the long head of the biceps, one must keep in mind the proximity of the musculocutaneous nerve. Despite this acknowledgment of the proximity of the musculocutaneous nerve medial to the site of the biceps tenodesis, there is, to the best of our knowledge, no literature describing musculocutaneous nerve injury associated with biceps tenodesis. The purpose of this report is to present a case of direct musculocutaneous nerve injury, after subacromial decompression with biceps tenodesis, which was treated with a neurolysis and tenodesis revision; complete recovery of musculocutaneous nerve function is reported after near-complete clinical loss of elbow flexion, as well as loss of sensation in the lateral antebrachial cutaneous nerve distribution.
A male military serviceman was evaluated for a long history of left shoulder problems. He was 34 years old, righthand dominant, and otherwise healthy. His initial shoulder evaluation was conducted by an outside physician in 2005. By MRI, he was diagnosed with a partial biceps tendon tear and a subacromial impingement with a large flap on the anterior-inferior glenoid labrum, which correlated with his clinical findings. He was treated nonoperatively. The patient had expectations of returning to the marines, with high-demand use of his shoulder, and the symptoms were unrelenting. Thus, 2 years after the onset of symptoms, he underwent a left shoulder arthroscopic chondral debridement and drilling, debridement of a type I superior labrum anterior and posterior tear, arthroscopic subacromial bursectomy and anterior acromioplasty, and an arthroscopically assisted mini-open biceps tenodesis. Surgical findings included a partial rupture of the biceps tendon with fraying of the tendon, consistent with impingement. The biceps was tagged arthroscopically and transected proximal to the tag suture. A 3- to 4-cm incision was made over the plane between the inferior medial border of the pectoralis major and the conjoint tendons. After retraction of the inferior border of the pectoralis, the biceps tendon was delivered into the wound. A radiolucent bioabsorbable screw was then used to fix the biceps tendon to the proximal humerus.8 Postoperatively, the patient experienced left arm weakness and numbness. His elbow flexion strength progressively deteriorated. An electromyogram, performed at 2 months postoperatively, showed severe injury to sensory and motor components of the musculocutaneous nerve. Acute denervation in the left biceps muscle was diagnosed with a marked decrease in the number of motor units activated. He was referred to our institution for evaluation and treatment. At evaluation 3 months after his procedure, he had extreme elbow flexion weakness and atrophy. He had extremely reduced elbow flexion strength (grade 2/5) with
† Address correspondence to Ann E. VanHeest, MD, University of Minnesota, Department of Orthopaedic Surgery, 2450 Riverside Avenue, Suite R200, Minneapolis, MN 55454 (e-mail:
[email protected]). No potential conflict of interest declared.
The American Journal of Sports Medicine, Vol. 37, No. 12 DOI: 10.1177/0363546509337406 © 2009 The Author(s)
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2468 Ma et al
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Figure 1. Anteroposterior radiograph of the left proximal humerus, which shows a radiolucent circle at the site where the tenodesis screw had been placed.
no palpable biceps firing. Physical examination of the arm diameter above the elbow revealed an atrophy of 4 cm, compared with the contralateral side. The patient had complete sensory loss in the lateral antebrachial cutaneous nerve distribution. Radiographs were taken, as shown in Figure 1. With no clinical or electromyographic improvement at 5 months postoperatively, the patient underwent musculocutaneous nerve exploration. The incision site of his previous biceps tenodesis was extended proximally to the coracoid level and distally to 3 cm. The tenodesis screw was palpated and found medial to the pectoralis insertion. The musculocutaneous nerve was wrapped around the site of the biceps tenodesis. As shown in Figure 2, the musculocutaneous nerve was in full continuity but wrapped around the long head of the biceps, coming completely lateral to the tenodesis and back underneath the biceps itself. This finding confirmed that the long head of the biceps had been tenodesed, with the musculocutaneous nerve wrapped around the tendon at the site of tenodesis. The tenodesis was taken down; the long head of the biceps was then unwrapped from the musculocutaneous nerve; and neurolysis was performed. The biceps tendon was then retenodesed. The nerve had an area of narrowing at the site where it had maximum stretch around the long
Figure 2. Musculocutaneous nerve in continuity but wrapped around the long head of the biceps at the tenodesis site. Reprinted with permission from Shounuck Patel. head of the biceps, but there was no evidence of in situ neuroma; thus, neurolysis alone became the recommended treatment. Postoperatively, the patient had immediate return of biceps firing and improvements in numbness and pain. Two months postoperatively, elbow flexion against gravity demonstrated grade 5/5 strength. Arm circumference, as measured above the elbow, demonstrated a 3-cm difference, a 1-cm improvement. The patient has continued to improve, with increasing range of motion and elbow flexion strength. At 1 year after surgery, he had complete return of elbow and shoulder function and so returned to the marines for active duty.
DISCUSSION This case report details musculocutaneous nerve entrapment around the biceps after tenodesis. Despite being discussed as a possible complication of biceps tenodesis,4 musculocutaneous nerve injury after biceps tenodesis has, to our best knowledge, not been documented in the literature. This patient had persistent shoulder pain with a partial biceps tendon tear and was thus a good surgical candidate
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for tenodesis. Sethi et al5 have published a set of recommendations for biceps tenodesis, including • greater than 25% partial-thickness tearing of the tendon, • chronic atrophic changes of the tendon, • any luxation of the biceps tendon from the bicipital groove, • any disruption of associated bony or ligamentous anatomy of the bicipital groove that would make autotenodesis likely, and • any reduction in the size of the tendon that is more than 25%. Partial-thickness tearing of the biceps tendon was the indication for biceps tenodesis in this case report. Other reports of nerve compression after tendon transfer have been reported.3,6,7,9 In these cases, nerve compression occurred after transfer of a tendon over a nerve, which caused an extrinsic compression of the nerve. In our case, the musculocutaneous nerve was stretched around the tenodesed long head of the biceps, making our case unique to the literature regarding the nerve involved and the injury modality. Most likely, the nerve entrapment around the tenodesis site occurred because our patient was muscular and because the tenodesis site was fairly distal (as seen in Figure 1); poor visualization of the tenodesis site, owing to the large size of his muscles, allowed the complication to occur without recognition. Our patient made a full recovery once (1) the iatrogenic injury was identified, (2) the biceps tenodesis was taken down, (3) the nerve was routed back to its anatomic course, and (4) the biceps tendon was retenodesed.
Our recommendation is that care be taken during a biceps tenodesis to directly visualize the tenodesis site; protecting the musculocutaneous nerve medial to the site of the tenodesis should allow the nerve to maintain its anatomic position. If an injury occurs to the musculocutaneous nerve, nerve exploration is indicated, with decompression and tenodesis revision. REFERENCES 1. Becker DA, Cofield RH. Tenodesis of the long head of the biceps brachii for chronic bicipital tendinitis: long-term results. J Bone Joint Surg Am. 1989;71:376-381. 2. Boileau P, Baque F, Valerio L, Ahrens P, Chuinard C, Trojani C. Isolated arthroscopic biceps tenotomy or tenodesis improves symptoms in patients with massive irreparable rotator cuff tears. J Bone Joint Surg Am. 2007;89:747-757. 3. Brutus JP, Mattoli JA, Palmer AK. Unusual complication of an opposition tendon transfer at the wrist: ulnar nerve compression syndrome. J Hand Surg [Am]. 2004;29:625-627. 4. Neer CSI. Treatment of impingement lesions of the biceps. In: Reines L, ed. Shoulder Reconstruction. Philadelphia, PA: WB Saunders Co; 1990:135. 5. Sethi N, Wright R, Yamaguchi K. Disorders of the long head of the biceps tendon. J Shoulder Elbow Surg. 1999;8:644-654. 6. Spinner RJ, Spinner M. Superficial radial nerve compression following flexor digitorum superficialis opposition transfer: a case report. J Hand Surg [Am]. 1996;21:1091-1093. 7. Tomaino MM, Wasko MC. Ulnar nerve compression following flexor digitorum superficialis tendon transfers around the ulnar border of the forearm to restore digital extension: case report. J Hand Surg [Am]. 1998;23:296-299. 8. Wiley WB, Meyers JF, Weber SC, Pearson SE. Arthroscopic assisted mini-open biceps tenodesis: surgical technique. Arthroscopy 2004;20: 444-446. 9. Wood VE. Nerve decompression following opponensplasty as a result of wrist anomalies: report a case. J Hand Surg [Am]. 1980;5:279-280.
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