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SCIENTIFIC ARTICLE

Snapping ElbowWith Congenital Radial Head

Dislocation: Case Report

Masahiro Maruyama, MD, Masatoshi Takahara, MD, PhD, Noriaki Kikuchi, MD, PhD, Kazuo Ito, MD, PhD,Tadayoshi Watanabe, MD, Toshihiko Ogino, MD, PhD

An 11-year-old boy with congenital radial head dislocation experienced painful snapping ofhis left elbow upon movement. He had no previous history of trauma. A plain radiograph ofhis left elbow showed anterior dislocation of the radial head and flexion deformity of thehypoplastic radial neck. Arthroscopy showed that the snapping of the elbow occurredbetween the annular ligament and the dislocated radial head during elbow flexion andextension. After the annular ligament was released, the snapping immediately disappeared.Five years after the surgery, the patient has no pain or snapping upon elbow movement.(J Hand Surg 2010;35A:981–985. Copyright © 2010 by the American Society for Surgeryof the Hand. All rights reserved.)

Key words Annular ligament, congenital radial head dislocation, snapping elbow.

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ONGENITAL RADIAL HEAD dislocation is the mostcommonly identified congenital elbow abnor-mality. It can occur in isolation, bilaterally, or in

ssociation with other inherited conditions.1–5

Some studies have reported that snapping elbow6–10

s secondary to interposition of the lateral synovialringe,7,8 the annular ligament,6,9 intra-articular freeodies, or dislocation of the triceps brachii muscle.10

owever, to our knowledge, there have been no pub-ished reports regarding snapping elbow with congeni-al radial head dislocation in the English-language lit-rature. In the Japanese-language literature, Kurihara etl.11 first described snapping elbow associated withongenital radial head dislocation in 1988, and 4 casesf snapping elbow associated with congenital radialead dislocation have since been reported.11–14

We present a case with painful snapping of the elbowssociated with congenital anterior dislocation of the radial

From the Department of Orthopaedic Surgery, Yamagata University School of Medicine, YamagataCity, Japan.

Received for publication February 25, 2009; accepted in revised form February 22, 2010.

No benefits in any form have been received or will be received related directly or indirectly to thesubject of this article.

Corresponding author: Masatoshi Takahara, MD, PhD, Department of Orthopaedic Surgery,Yamagata University School of Medicine, 2-2-2, Yamagata City, 990-9585, Japan; e-mail:mtakahar@med.id.yamagata-u.ac.jp.

0363-5023/10/35A06-0017$36.00/0

pdoi:10.1016/j.jhsa.2010.02.026

©

ead, which resolved after surgical release of the annularigament using arthroscopy. We report the details of thisase and discusses the pathogenesis of snapping elbowssociated with congenital radial head dislocation.

ASE REPORTboy who had congenital, bilateral, restricted forearm

otation presented to our hospital at 3 years of age. Thereas no history of trauma. The active range of his right

lbow motion was from 5° of hyperextension to 105° ofexion, and the range of motion at his left elbow was from° to 110°. The active range of his left forearm motion,easured at the radial styloid, was pronation to 80° and

upination to within 20° of neutral rotation, and his rightorearm was pronation to 60° and supination to within 20°f neutral rotation. Plain radiographs of both elbowshowed anterior dislocation of the radial heads. The prox-mal radius was hypoplastic compared to the proximallna (Fig. 1). Although both sides of the ulna were slightlyonvex, the patient was diagnosed to have bilateral con-enital radial head dislocation.

Because the patient complained of severe restrictionf rotation for both forearms, he had rotational osteot-my of the right radius at 5 years of age and an addi-ional rotational osteotomy of the left radius at 7 yearsf age. The patient’s osteotomy was performed at thensertion of the pronator teres on the radius.15 The

ronation position was manually corrected to allow for

ASSH � Published by Elsevier, Inc. All rights reserved. � 981

the proximal ulna.

radioulnar joint.

982 SNAPPING ELBOW WITH RADIAL HEAD DISLOCATION

90°of supination of the palm, and a long arm cast wasapplied without internal fixation.

When the patient was 11 years old, he presented withpain in his left elbow associated with snapping onmovement. He had no history of trauma. There was nodeformity and no tenderness at his left elbow joint. Theactive range of his left elbow motion was from 15° ofhyperextension to 115° of flexion, with 30° of pronationand supination to 20° beyond the neutral position; thesupination–pronation arc was 10°. During elbow flex-ion, painful snapping occurred at 90° of flexion of theelbow. Likewise, during elbow extension, painful snap-ping occurred at 30° of flexion of the elbow. Snappingdid not occur during pronation or supination. The snap-ping was palpable at the radial head. The patient had nocomplaints concerning his left wrist.

A plain radiograph of his left elbow showed ananterior dislocation of the radial head with dome-shaped deformity and anterior flexion of the radial neck,and there was no obvious osteosynthesis of the radio-ulnar joint (Fig. 2). Magnetic resonance imagingshowed no cartilaginous or osseous union of the radio-ulnar joint, synovial fringe, or abnormalities, except foranterior dislocation of the left radial head (Fig. 3).

He was treated conservatively with oral anti-inflammatory agents. Because the pain did not subsidewith 4 months of conservative therapy, the patient sub-sequently had surgical treatment. Arthroscopic findingsfrom anteromedial portals demonstrated deformation ofthe radial head with dislocation to the anterolateral side.There was no proliferation of the synovium. The dislo-cated radial head was arthroscopically observed uponelbow flexion of 90° or more, although it was hidden bythe anterior capsule at elbow flexion of 30° or less.

FIGURE 1: A plain radiograph of both elbows and forearmanteriorly, and the proximal radius was hypoplastic compared to

s in our patient. The radial heads of both sides were dislocated

When the elbow was passively extended from full flex-

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FIGURE 2: A plain radiograph of both elbows. The plainradiograph of the patient’s left elbow shows the anteriordislocation of the radial head and anterior flexion of the radialneck, but there is no obvious osseous synostosis of the

FIGURE 3: A Axial and B coronal magnetic resonance image(T2-weighted intensity) of the patient’s left elbow. There is nocartilaginous or osseous union of the radioulnar joint, synovialfringe, or abnormalities, except for anterior dislocation of the

left radial head.

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SNAPPING ELBOW WITH RADIAL HEAD DISLOCATION 983

ion, the radial head disappeared beneath the annularligament, with snapping observed at an elbow flexion of30° (Fig. 4A). When the elbow was passively flexedfrom full extension, the radial head suddenly appeared,with snapping at an elbow flexion of 90° (Fig. 4B).Close observation revealed that the snapping phenom-enon occurred between the annular ligament and theradial head. We then inserted a knife through the an-terolateral portal and released the anterolateral portionof the annular ligament (Fig. 5). After the release, thesnapping immediately disappeared. After surgery, thepatient had no pain or snapping upon elbow movement.The active range of his left elbow was not altered after

FIGURE 4: Arthroscopy of the left elbow from the anteromeflexion, the radial head disappeared beneath the annular ligamother hand, when the elbow was passively flexed from full eelbow flexion of 90°. R, radial head; H, humeral capitellum.

FIGURE 5: Arthroscopic release of the annular ligament ofannular ligament and radial head. B The anterolateral portionthrough the anterolateral portal. (R, radial head; H, humeral cap

the surgery. Five years after the surgery, no pain or

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snapping has recurred, and the active range of his leftelbow motion from hyperextension is 15° to 115°, with90° of pronation and supination to within 20° of neutral.

DISCUSSIONMc Farland16 described 7 specific radiographic findingsof congenital radial head dislocation: (1) a relativelyshort or long radius, (2) a hypoplastic or absent capit-ulum of the humerus, (3) a partially defective trochleaof the humerus, (4) a prominent ulnar epicondyle, (5) adome-shaped radial head with a long, narrow neck, (6)grooving of the distal radius, and (7) anterior curvatureof the posterior outline of the ulna. However, some

portal. A When the elbow was passively extended from fullwith snapping observed at an elbow flexion of 30°. B On thesion, the radial head suddenly appeared, with snapping at an

left elbow. A The snapping phenomenon occurs between anhe annular ligament is released, using a sharp knife insertedm; arrow, annular ligament.)

dialent,xten

theof t

authors1,17–19 have asserted that traumatic dislocation

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984 SNAPPING ELBOW WITH RADIAL HEAD DISLOCATION

of the radial head could show most of these findings ifposttraumatic remodeling had occurred. Many au-thors1,4,16,17,20 have pointed out that the posterior bor-der of the ulna is concave in congenital radial headanterior dislocation. On the other hand, Lincoln et al.reported21 that the posterior border of the ulna is convexin posttraumatic radial head anterior dislocation.

Mizuno et al.22 used arthrographic findings to differ-entiate between congenital and traumatic dislocation.The arthrography of congenital dislocation showed thatthe humeroulnar, radioulnar, and radiohumeral jointswere all intra-articular. On the other hand, the arthrog-raphy of traumatic dislocation showed that only thehumeroulnar joint was intra-articular, and the dislocatedradial head was extra-articular.

Although some authors19,23 found that most patientswith congenital radial head dislocation had minimal func-tional impairment, Miura19 found that several patientscomplained of restricted flexion and extension of the el-bow joint and supination and pronation of the forearm.

Our patient had bilateral dislocation with no history oftrauma. Although the range of forearm motion in our casewas severely restricted, there was no obvious evidence ofcongenital radioulnar synostosis by x-ray or magnetic res-onance imaging. Also, both sides of the radial head werehypoplastic and showed dome-shaped deformity. We con-firmed arthroscopically that the humeroulnar and radio-humeral joints were intra-articular. Therefore, our diagno-sis in this patient was congenital radial head dislocationrather than posttraumatic radial head dislocation.

To our knowledge, there are only 4 cases of snappingelbow with congenital radial head dislocation that havebeen reported in the Japanese-language literature11–14

TABLE 1. Reported Cases of Snapping Elbow With

ReportsGender,Age (y)

Forearm Range of MotionSupination/Pronation

Kurihara H et al.11 Male, 16 75°/70° A

Otori et al.12 Male, 14 90°/80° A

Kurihara Y et al.13 Male, 13 100°/90° A

Kokubu et al.14 Female, 37 90°/40° A

Our case Male, 11 20° beyond neutralposition / 30°

A

and no cases in the English-language literature.

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The present case and the previously reported cases ofsnapping or locking elbow associated with congenitalradial head dislocation are summarized in Table 1.11–14

Including our case, all elbow radiographs showed an-terior dislocation of the radial head, and 3 of the 5 casesshowed an open epiphyseal plate at the radial head. Thepreviously reported cases of snapping or locking elbowassociated with congenital radioulnar synostosis aresummarized in Table 2.11,24–29 Seven of the 9 casespresented in Table 2 were found in teenagers, and alltheir elbow radiographs, according to the Cleary andOmer classification,30 were classified as type IV withan open epiphyseal plate. Thus, the growth spurt of theradius and an anterior dislocation of the radial headmight be more susceptible to snapping.

The etiology of snapping elbow associated with con-genital radial head dislocation includes a hypertrophic an-terior capsule,11 a ligament-like structure,11–13 or a syno-vial fringe.14 The etiology of our case was an annularligament. Some authors11,12,14 have used open surgery toremove the ligament-like structure or synovial fringe.Kurihara et al.13 found snapping tissue using arthroscopyand removed the radial head through an additional, smallincision. In our case, no histological examination wasperformed on the excised snapping tissue; however, uponarthroscopy, it was clearly revealed to be the annularligament. Arthroscopic surgery allowed us to identify thesnapping tissue around the radial head, and we were ableto remove it with minimal invasion, using arthroscopicsurgery and a minimal incision.

We performed partial release of the anterolateralportion of the annular ligament. At the final examina-tion, 5 years after the surgery, the patient had no elbow

genital Radial Head Dislocation

Radiographs EtiologySurgical ProcedureResection Tissue

or dislocation Annular ligament–likestructure,hypertrophicanterior capsule

OpenCapsule and annular

ligament–likestructure

or dislocation Annular ligament–likestructure

OpenAnnular ligament–like

structure

or dislocation Annular ligament–likestructure

OpenRadial head

or dislocation Synovial fringe ArthroscopySynovial fringe

or dislocation Annular ligament ArthroscopyAnnular ligament

Con

Plain

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nteri

nteri

nteri

nteri

pain or elbow instability, and a lateral radiograph of his

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SNAPPING ELBOW WITH RADIAL HEAD DISLOCATION 985

left elbow showed no findings of the displacement ofthe radial neck. These facts did not suggest that thepartial release of the annular ligament provided clini-cally functional problems within 5 years, although thelong-term consequences are unknown.

REFERENCES1. Mital MA. Congenital radioulnar synostosis and congenital disloca-

tion of the radial head. Orthop Clin North Am 1976;7:375–383.2. Agnew DK, Davis RJ. Congenital unilateral dislocation of the radial

head. J Pediatr Orthop 1993;13:526–528.3. Mardam-Bey T, Ger E. Congenital radial head dislocation. J Hand

Surg 1979;4:316–320.4. Ogino T, Ishii S, Usui M, Minami A, Hukuta K, Katou S. Clinical

feature of the so-called congenital radial head dislocation [in Japa-nese]. Rinshou-Seikeigeka 1982;17:439–445.

5. Sachar K, Mih AD. Congenital radial head dislocations. Hand Clin1998;14:39–47.

6. Clarke R. Symptomatic, lateral synovial fringe (plica) of the elbowjoint. Arthroscopy 1988;4:112–116.

7. Akagi M, Nakamura T. Snapping elbow caused by the synovial foldin the radiohumeral joint. J Shoulder Elbow Surg 1998;7:427–429.

8. Wightman JAK. Clicking elbow from a torn annular ligament: reportof a case. J Bone Joint Surg 1963;45B:380–381.

9. Aoki M, Okamura K, Yamashita T. Snapping annular ligament of theelbow joint in the throwing arms of young brothers. Arthroscopy2003;19:E4–E7.

10. Dreyfuss U, Kessler I. Snapping elbow due to dislocation of themedial head of the triceps. A report of two cases. J Bone Joint Surg1978;60B:56–57.

11. Kurihara H, Kamata M, Uno H, Arisawa N, Fukuda K, Kizuki S, etal. Three cases of snapping elbow [in Japanese]. Seikei Geka 1988;39:711–718.

12. Otori S, Takai H, Amano K. A case of snapping elbow with con-genital radial head dislocation [in Japanese]. Tochigiken seikeigek-aikaikaisi 1997;12:25–28.

13. Kurihara Y, Aizawa M, Muneta T. Arthroscopy for snapping elbowdue to congenital radial head dislocation: a case report [in Japanese].Kansetsukyo 2004;29:155–159.

14. Kokubu Y, Nishiura Y, Hara Y, Yoshii Y, Ochiai N. Snapping elbowwith congenital dislocation of the radial head [in Japanese]. J Jpn

TABLE 2. Reported Cases of Snapping Elbow Assoc

Reports Gender, Age (y)Classification of Pla

Radiographs‡

Kikuchi et al.24 Male, 16* Type IV

Kurihara et al.11 Male. 24 Type IV

Takamine et al.25 Male, 12 Type IV

Horii et al.26 Male, 13 Type IV

Osaka et al.27 Female, 51 Type IV

Masuko et al.28 Male, 12† Type IV

Male, 13† Type IV

Tanaka et al.29 Male, 12* Type IV

�These cases did not have snapping, but rather locking. †These cases dOmer classification (type I, fibrous union with a reduced, normal-appeosseous synostosis with posterior dislocation of a hypoplastic radial hehead, with the radial head usually mushroom-shaped).

Elbow Soc 2007;14:228–230.

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15. Kanauchi U, Ogino T, Takahara M et al. Rotational wedge osteot-omy at the shaft of the radius for congenital radio-ulnar synostosis[in Japanese]. Seikei Saigai Geka 2008;51:183–189.

16. Mc Farland B. Congenital dislocation of the head of the radius.British J Surg 1936;24:41–49.

17. Caravias D. Some observations on congenital dislocation of the headof the radius. J Bone Joint Surg 1957;39B:86–90.

18. Lloyd-Roberts GC, Bucknill TM. Anterior dislocation of the radialhead in children: aetiology, natural history and management. J BoneJoint Surg 1977;59B:402–407.

19. Miura T. Congenital dislocation of the radial head. J Hand Surg1990;15B:477–481.

20. Almquist EE, Gordon LH, Blue AI. Congenital dislocation of thehead of the radius. J Bone Joint Surg 1969;51A:1118–1127.

21. Lincoln TL, Mubarak SJ. “Isolated” traumatic radial-head disloca-tion. J Pediatr Orthop 1994;14:454–457.

22. Mizuno K, Usui Y, Kohyama K, Hirohata K. Familial congenitalunilateral anterior dislocation of the radial head: differentiation fromtraumatic dislocation by means of arthrography. A case report.J Bone Joint Surg 1991;73A:1086–1090.

23. Echtler B, Burckhardt A. Isolated congenital dislocation of the radialhead. Good function in 4 untreated patients after 14–45 years. ActaOrthop Scand 1997;68:598–600.

24. Kikuchi H, Tanaka K, Oka M, Toihara M, Kita H, Kondo M. Twocases of congenital radioulnar synostosis [in Japanese]. Kansetsu-Geka 1984;3:233–237.

25. Takamine H, Itoh Y, Uzawa M, Andoh Y, Nishiura Y, Ishii Y. Eightcases of intra-articular snapping elbow [in Japanese]. J Jpn ElbowSoc 1996;3:127–128.

26. Horii E, Koh S, Nakamura S. A case of snapping elbow with congenitalradioulnar synostosis [in Japanese]. J Jpn Elbow Soc 2000;7:113–114.

27. Osaka E, Nagaoka M, Saitou A, Ryu J. A case of snapping elbowwith congenital radioulnar synostosis [in Japanese]. J Jpn Elbow Soc2003;10:91–92.

28. Masuko T, Kato H, Minami A, Inoue M, Hirayama T. Surgicaltreatment of acute elbow flexion contracture in patients with con-genital proximal radioulnar synostosis. A report of two cases. J BoneJoint Surg 2004;86A:1528–1533.

29. Tanaka K, Moritomo T, Murase T, Goto A. A case of locking elbowassociated with congenital radioulnar synostosis with anterior radialhead dislocation [in Japanese]. J Jpn Elbow Soc 2006;13:153–154.

30. Cleary JE, Omer GE. Congenital proximal radio-ulnar synostosisnatural history and functional assessment. J Bone Joint Surg 1985;

d With Congenital Radioulnar Synostosis

Etiology Surgical Procedure

Hypertrophic anterior capsule Open

Hypertrophic ligament-like structure Open

Annular ligament–like structure,hypertrophic anterior capsule

Open

Annular ligament Arthroscopy

Lateral synovial fringe Arthroscopy, open

Annular ligament–like structure Open

Annular ligament–like structure Open

A part of lateral ligament complex Arthroscopy, open

have snapping, but rather acute contracture. ‡According to Cleary andradial head; type II, osseous synostosis with normal findings; type III,pe IV, a short osseous synostosis with anterior dislocation of the radial

iate

in

id notaringad; ty

67A:539–545.

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