Anconeus Epitrochlearis As a Source of Medial Elbow Pain in Baseball Pitchers

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Anconeus Epitrochlearis as a Source of Medial Elbow Pain in Baseball Pitchers

Article in Orthopedics · July 2012 DOI: 10.3928/01477447-20120621-39 · Source: PubMed

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Anconeus Epitrochlearis as a Source of Medial Elbow Pain in Baseball Pitchers

Xinning Li, MD; Joshua S. Dines, MD; Matthew Gorman, MD; Orr Limpisvasti, MD; Ralph Gambardella, MD; Lou Yocum, MD

abstract Full article available online at Healio.com/Orthopedics. Search: 20120621-39

Medial elbow pain is reported in 18% to 69% of baseball players aged of 9 and 19 years. This is due to the large valgus stresses focused on the medial side of the elbow during overhead activities. In overhead throwers and pitchers, pain can be attributed to valgus extension overload with resultant posteromedial impingement, overuse of the flexor–pronator musculature resulting in medial epicondylitis, or occasional muscle tears or ruptures. The anconeus epitrochlearis is a known cause of cubital tunnel syndrome and has been postulated as a source of medial elbow pain in overhead athletes. Figure: Axial T1-weighted magnetic resonance image showing the anconeus epitrochlearis muscle This article describes the cases of 3 right-handed baseball pitchers with persistent (arrow) attaching from the inferior surface of the right-sided medial elbow pain during throwing despite a prolonged period of rest, medial epicondyle to the medial olecranon. physical therapy, and nonsteroidal anti-inflammatory drugs. Two patients had symptoms of cubital tunnel syndrome as diagnosed by electromyogram and nerve conduction studies and the presence of the anconeus epitrochlearis muscle per magnetic resonance imaging. All patients underwent isolated release of the anconeus muscle without ulnar nerve transposition and returned to their previous levels of activity.

The diagnosis and treatment of pitchers who present with medial-sided elbow pain can be complex. The differential should include an enlarged or inflamed anconeus epitrochlearis muscle as a possible cause. Conservative management should be the first modality. However, surgical excision with isolated release of the muscle can be successful in returning patients with persistent pain despite a trial of conservative management to their previous levels of function.

Drs Li and Dines are from the Division of Sports Medicine and Shoulder Surgery, Hospital for Special Surgery, New York, New York, and Drs Gorman, Limpisvasti, Gambardella, and Yocum are from the Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California. Drs Li, Dines, Gorman, Limpisvasti, Gambardella, and Yocum have no relevant financial relation- ships to disclose. Correspondence should be addressed to: Xinning Li, MD, Division of Sports Medicine and Shoulder Surgery, Hospital for Special Surgery, New York, NY 10021 ([email protected]). doi: 10.3928/01477447-20120621-39

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edial elbow pain in overhead no cases have been reported of anconeus aris muscle on MRI (Figure). Significant athletes is common, with a epitrochlearis muscle compression on the edema also existed in the anconeus epi- Mreported incidence in 18% ulnar nerve as a source of pain in this pa- trochlearis muscle on both MRI images. to 69% of baseball players aged 9 to 19 tient population. This article describes 3 Because all 3 patients had failed a pe- years.1 The pain can be due to the large baseball pitchers with medial elbow pain riod of nonoperative treatment (at least valgus stresses focused on the medial side caused by the anconeus epitrochlearis 3 months) and were unable to return to of the elbow during overhead activities. As muscle who were able to return to over- throwing without pain and neurologic a result, pitchers are at an increased risk head athletics after surgical excision and symptoms, surgical intervention was ad- of injury to the medial elbow structures. release. vised. All 3 patients underwent surgical Pain can be attributed to valgus extension excision and release of the anconeus epi- overload with resultant posteromedial im- Case Reports trochlearis muscle. No patients exhibited pingement, overuse of the flexor–pronator The 3 patients were right-handed male ulnar nerve instability intraoperatively musculature resulting in medial epicondy- baseball players aged 17, 17, and 19 years when placed through range of motion litis, or occasional muscle tear or rupture, (patients 1, 2, and 3, respectively) who after excision and release of the muscle. particularly in overhead throwers and presented with persistent right-sided me- In patients 1 and 2, an ulnar nerve neu- pitchers.2-4 Ulnar neuropathy is another dial elbow pain with throwing despite at rolysis was also completed, but no for- common cause of medial elbow pain and least 3 months of rest, physical therapy, mal transposition of the nerve was com- can result from traction, compression, or and nonsteroidal anti-inflammatory drugs. pleted. In patient 2, who had a diagnosis friction on the nerve throughout its ana- Patients 1 and 2 reported ulnar-sided of cubital tunnel syndrome with negative tomic course.2,5,6 numbness and tingling on the forearm ra- preoperative MRI images, the anconeus The anconeus epitrochlearis is a known diating down to the hand that most nota- epitrochlearis muscle was seen, released, cause of cubital tunnel syndrome5-10 and bly occurred when throwing. They were and excised during surgical exploration. has been postulated as a source of medial diagnosed with cubital tunnel syndrome, In addition to the accessory epitrochle- elbow pain in overhead athletes.2 Its in- and electromyogram and nerve conduc- aris release, patient 3 had an incompetent cidence in the general population varies tion studies documented compression of and degenerative medial ulnar collateral from 4% to 34% as reported by several the ulnar nerve across the elbow. Patient ligament and underwent concomitant cadaveric studies.8,10 This muscle over- 3 was diagnosed with incompetence of ligament reconstruction using the figure-8 lies the ulnar nerve posteriorly, becomes the medial ulnar collateral ligament and technique with gracilis autograft without more taut in flexion, and is a potential had pain with valgus stress and milking ulnar nerve transposition.12 source of compression.8 Several cases maneuvers. All 3 patients had preopera- Patients 1 and 2 were able to return to have been reported of cubital tunnel syn- tive magnetic resonance imaging (MRI) throwing competitively at 7 and 8 weeks drome causing medial-sided elbow pain in scans, and patients 1 and 3 demonstrated postoperatively, respectively. They re- adolescent baseball pitchers.11 However, the presence of the anconeus epitrochle- turned to their previous levels of compe-

A B C Figure: Axial T1-weighted magnetic resonance image showing the anconeus epitrochlearis muscle (arrow) attaching from the inferior surface of the medial epicondyle to the medial olecranon (A). Axial T2-weighted magnetic resonance image showing significant edema within the muscle(arrow) (B). Sagittal T1-weighted magnetic resonance image showing the enlarged anconeus epitrochlearis muscle medial to the olecranon (arrow) (C).

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tition and had complete symptom resolu- ers and their ability to return to throwing yielded relief or substantial improvement tion. At 1-year follow-up, both patients after surgical excision and release. in several reported cases.8 Chalmers18 were doing well, with no recurring symp- Diagnosis should be made on the reported subluxation of the ulnar nerve toms. Patient 3 began an interval-throwing basis of history, physical examination, over the medial epicondyle after muscle program 4 months postoperatively and and diagnostic imaging studies. If ulnar excision in 7 of 8 patients. As a result, returned to his preinjury level of play 1 nerve symptoms predominate, electro- he believed that transposition of the ul- year postoperatively. All 3 patients had myography and nerve conduction stud- nar nerve was a necessary stabilizing complete resolution of their medial-sided ies should be obtained to localize the procedure.18 Dahners and Wood7 also elbow pain and forearm numbness after compression to the elbow. Byun et al6 advocated release and anterior subcuta- surgical release of the anconeus epitroch- reported a group of 15 patients with ul- neous transposition of the ulnar nerve. learis muscle. nar neuropathy caused by the anconeus All patients treated by this modality have epitrochlearis muscle and found that demonstrated improvement in symptoms Discussion symptom duration tended to be shorter in and function. However, in the current 3 This article describes an uncom- this group of patients. Furthermore, these patients, the authors performed an iso- mon cause of medial-sided elbow pain patients had lower motor amplitude and lated excision of the anconeus epitroch- in throwing athletes. The anconeus epi- shorter segments of latency prolongation learis muscle without transposition, and trochlearis can compress the ulnar nerve, (between medial epicondyle and 2 cm no patients showed evidence of ulnar resulting in cubital tunnel syndrome.9 above), and 27% had complete conduc- nerve instability or persistent symptoms Accurate diagnosis and surgical treatment tion block when compared with patients up to 1-year follow-up. No persistent can reliably return these athletes to their with isolated ulnar neuropathy.6 symptoms of ulnar nerve subluxation oc- previous levels of play. Magnetic resonance imaging can also curred. In patients 1 and 2, all symptoms The anconeus epitrochlearis muscle be helpful in elucidating the cubital tun- resolved after release of the anconeus is superficial to the ulnar nerve and at- nel and surrounding structures, including epitrochlearis muscle without transposi- taches from the inferior surface of the the anconeus epitrochlearis muscle. The tion. Jeon el al19 also reported the isolat- medial epicondyle to the medial cortex of anconeus epitrochlearis muscle is best ed release of the anconeus epitrochlearis the olecranon.9 It takes a similar anatomic viewed on axial images, where the rela- muscle without ulnar nerve transposition course as the cubital tunnel retinaculum. tionship of the ulnar nerve and adjacent in an amateur weight lifter with cubital Some authors postulate that the cubital soft tissue is clearly delineated. If edema tunnel syndrome. The patient had com- tunnel retinaculum is the remnant of the exists in the muscle, it will be best appre- plete resolution of his symptoms, with no anconeus epitrochlearis muscle.9,13 This ciated with short T1 inversion recovery residual ulnar nerve instability.19 muscle protects the ulnar nerve and as- MRI.16 Edema is abnormal in the anco- Masear et al8 reported that excision sists the triceps muscle in preventing ulnar neus accessory muscle on MRI. Jeon et of the accessory anconeus epitrochlearis nerve subluxation. al17 reported 2 patients with edema seen muscle with ulnar nerve decompression The reported prevalence of having an in the anconeus epitrochlearis muscle re- without transposition was successful in anconeus epitrochlearis muscle is 4% to porting vague medial-sided elbow pain. alleviating symptoms in 5 patients; how- 34% in cadaver studies,14,15 and it exists One patient was managed conservatively ever, none of those patients were overhand in both elbows of approximately 25% of with local steroid injection and nonste- athletes. Other authors have recommend- patients with cubital tunnel syndrome.8 In roidal anti-inflammatory drugs, and the ed medial epicondylectomy and excision the majority of people who have no another patient underwent release with of the anconeus epitrochlearis muscle.20 coneus epitrochlearis muscle, it may be excision of the anconeus epitrochlearis The current authors’ experience suggests replaced by a band of tissue called the epi- muscle. Both patients recovered well, that muscle release and neurolysis are ap- trochleoanconeus ligament. This acces- with a short-term follow-up of less than propriate initial surgical measures in over- sory muscle is a well described source of 1 year. head athletes, including baseball pitchers. medial elbow pain in patients with cubital Recommendations for the surgical Ulnar nerve transposition should be re- tunnel syndrome. Although 1 previous treatment of medial elbow pain caused served for cases with persistent neurolog- study reported baseball pitchers returning by the anconeus epitrochlearis muscle ic symptoms. Consequently, the thrower to throwing after cubital tunnel release,11 have ranged from excision alone to ex- should be made aware of the potential for no previous studies have reported the an- cision followed by anterior transposition recurrent subluxation of the ulnar nerve coneus epitrochlearis muscle as a cause of of the ulnar nerve.8,18 Local decompres- after translocation, which may lead to medial-sided elbow pain in baseball pitch- sion and resection of the muscle mass subsequent transposition surgery.

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Conclusion 4. Slocum DB. Classification of elbow inju- tion in athletes: muscle-splitting approach ries from baseball pitching. Tex Med. 1968; without transposition of the ulnar nerve. J This article examines the accessory an- 64:48-53. Shoulder Elbow Surg. 2001; 10:152-157. coneus epitrochlearis muscle as a contrib- 5. Posner M. Compressive ulnar neuropathies 13. Sookur PA, Naraghi AM, Bleakney RR, Jalan utor to medial elbow pain in overhead ath- at the elbow: I. Etiology and diagnosis. J Am R, Chan O, White LM. Accessory muscles: letes. Nonoperative modalities and avoid- Acad Orthop Surg. 1998; 6:282-288. anatomy, symptoms, and radiologic evalua- tion. Radiographics. 2008; 28:481-499. ance of throwing should remain the main- 6. Byun SD, Kim CH, Jeon IH. Ulnar neuropathy caused by an anconeus epitrochlearis: 14. Von Clemens HJ. Zur morphologic des liga- stay of initial treatment. Recalcitrant cases clinical and electrophysiological findings. J mentum epitrochleoanconeum. Anat Anz. are candidates for surgical intervention. Hand Surg Eur Vol. 2011; 36:607-608. 1957; 104:343-344. Release of the anconeus epitrochlearis 7. Dahners LE, Wood FM. Anconeus epitrochle- 15. Mahakkanukrauh P, Surin P, Ongkana N, muscle without ulnar nerve transposition aris, a rare cause of cubital tunnel syndrome: a Sethadavit M, Vaidhayakarn P. Prevalence of case report. J Hand Surg. 1984; 9:579-580. accessory head of flexor pollicis longus mus- was successful in the management of the 8. Masear VR, Hill JJ Jr, Cohen SM. Ulnar cle and its relation to anterior interosseous Clin Anat current 3 patients, who were baseball compression neuropathy secondary to the an- nerve in Thai population. . 2004; 17:631-635. pitchers with medial-sided elbow pain coneus epitrochlearis muscle. J Hand Surg. with and without cubital tunnel syndrome. 1988; 13:720-724. 16. Vankan LB, Demeyere A, Perdieus D. Bilateral 9. O’Driscoll SW, Horii E, Carmichael SW, ulnar nerve compression by anconeus epitro- Overhead athletes are expected to return JBR-BTR Morrey BF. The cubital tunnel and ulnar neu- chearis muscle. . 2009; 92:120. to their previous levels of throwing post- ropathy. J Bone Joint Surg Br. 1991; 73:613- 17. Jeon IH, Fairbairn KJ, Neumann L, Wallace operatively. 617. WA. MR imaging of edematous anconeus 10. O’Hara JJ, Stone JH. Ulnar nerve compres- epitrochlearis: another cause of medial elbow Skeletal Radiol sion at the elbow caused by a prominent pain? . 2005; 34:103-107. References medial head of the triceps and an anconeus 18. Chalmers J. Unusual causes of peripheral 1. Magra M, Caine D, Mafulli N. A review of epitrochlearis muscle. J Hand Surg Br. 1996; nerve compression. Hand. 1978; 10:168- epidemology of pediatric elbow injuries in 21:133-135. 175. sports. Sports Med. 2005; 37:717-735. 11. Aoki M, Kanaya K, Aiki H, Wada T, 19. Jeon IH, Kim PT, Park IH, Kyung HS, Ihn 2. Chen FS, Rokito AS, Jobe FW. Medial elbow Yamashita T, Ogiwara N. Cubital tunnel syn- JC. Cubital tunnel syndrome due to the an- problems in the overhead-throwing athlete. J drome in adolescent baseball players: a re- coneus epitrochlearis in an amateur weight Am Acad Orthop Surg. 2001; 9:99-113. port of six cases with 3- to 5-year follow-up. lifter. Sicot Case Reports. 2002:1-6. Arthroscopy. 2005; 21:758. 3. Brogdon BG, Crow NE. Little leaguer’s el- 20. Hodgkinson PD, McLean NR. Ulnar nerve bow. Am J Roentgenol Radium Ther Nucl 12. Thompson WH, Jobe FW, Yocum LA, Pink entrapment due to epitrochleoanconeus mus- Med. 1960; 83:671-675. MM. Ulnar collateral ligament reconstruc- cle. J Hand Surg Br. 1994; 19:706-708.

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