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Isolated Avulsion Fracture of the Extensor Carpi Radialis Brevis Insertion Due to a Boxer’s Injury

by Scott W. Breeze, MD, Travis Ouellette, Matthew M. Mays, MD

Abstract

Avulsion fractures involving the radial wrist extensor tendons are extremely rare. Only 8 avulsion fractures of the extensor carpi radialis longus and 7 avulsion fractures of the extensor carpi radialis brevis have been previously reported. We know of no case involving an isolated avulsion fracture of the base of the third metacarpal where the extensor carpi radialis brevis attachment to the fracture fragment was still completely intact. This article reports a patient with an isolated avulsion fracture of the extensor carpi radialis brevis insertion treated by open reduction and internal fixation. The avulsion fracture was the result of a poor punching technique. The patient healed uneventfully, and returned to full painless activity. The senior author (S.W.B.) of this article is a former Tae Kwon Doe instructor and includes some editorial comments on proper technique for punching to avoid injury.

Avulsion fractures involving the radial wrist extensor tendons are rare. This article describes a patient with an isolated avulsion fracture of the extensor carpi radialis brevis insertion treated by open reduction and internal fixation.

Case Report

A 19-year-old man presented 2 days after injuring his dominant right hand in a street fight. He had punched someone in the face and his clenched fist had abruptly palmar flexed. He felt a pop over the dorsal aspect of his wrist followed by a painful, swollen bump.

Physical examination revealed significant swelling of the dorsum of the hand and wrist. His skin was intact and neurovascular examination was normal. Pain and guarding limited the remainder of the examination.

Plain radiographs revealed a large bony fragment dorsal to the carpal metacarpal joints (Figure 1). The exact origin of the fragment was uncertain, so magnetic resonance imaging (MRI) was obtained to rule out significant soft tissue injuries and localize the bony injury. The MRI revealed an isolated intra-articular fracture of the base of the third metacarpal. The extensor carpi radialis brevis was still attached to the fragment. No other ligamentous or osseous injuries were noted.

The injury was approached through a dorsal incision over the third carpal metacarpal region. A 1×1-cm bony fragment included 50% of the articular surface of the third metacarpal base. The extensor carpi radialis brevis tendon was still well attached to the fragment. The fragment was rotated >90° due to the pull of the extensor carpi radialis brevis. The third carpal metacarpal joint was stable to stress examination. The fracture was easily reduced anatomically and provisionally stabilized with a 0.035-in Kirschner wire. Definitive fixation was obtained with a 2.0-mm mini-fragment screw, as well as a 1.5-mm mini-fragment screw to control rotation.

Immediately postoperatively, the wrist was immobilized in 20° of extension in a padded splint. After 1 week, the wrist was placed in a short arm cast for 4 weeks. After a total of 5 weeks, the cast was removed and the patient began working on his range of motion. Ten weeks postoperatively, the patient had full range of motion and strength and was completely pain free. Radiographs revealed a healed fracture with anatomic alignment.

Discussion

Extensor carpi radialis brevis avulsion fractures are rare, as are extensor carpi radialis longus avulsion fractures. The mechanism of injury generally consists of an awkward acute forceful flexion on the wrist while simultaneously trying to maintain a neutral wrist posture.

Cobbs et al1 reported a similar case involving a boxing injury. The patient had also sustained a ligamentous injury causing instability of the third carpal metacarpal joint. Tsiridis et al2 reported a case where a cyclist hit a car with his fist during an accident. The injury required open reduction and internal fixation (ORIF) and tendon repair. Boles and Durbin3 reported a case of simultaneous avulsion fractures of the extensor carpi radialis longus and extensor carpi radialis brevis when a softball player fell and sustained a similar acute flexion injury of his gloved hand. These fractures also necessitated ORIF and individual tendon repair. Rotman and Pruitt4 reported a case of an extensor carpi radialis brevis avulsion fracture that occurred after a fall. An associated fracture of the third metacarpal shaft was also present and required ORIF. Johnson and Puttler5 reported an avulsion fracture of the extensor carpi radialis brevis due to a hyperflexion injury while moving a heavy object down a flight of stairs. The injury required ORIF and tendon repair.

We believe our case is the first reported in the literature of a purely isolated avulsion fracture of the extensor carpi radialis brevis. In our case the extensor carpi radialis brevis tendon did not require separate repair and there were no other associated injuries. This injury was treated solely by ORIF of the avulsed fragment.

The senior author (S.W.B.) had the opportunity to study boxing and martial arts over the past 30 years. Correct punching technique requires simultaneous contact of the index and long finger metacarpal heads with the target on impact. Rigid connection of the second and third metacarpals with the wrist, forearm, elbow, shoulder, and torso also need to occur at that moment to transfer maximum energy to the target. To achieve this, the wrist is slightly ulnar deviated to align the second and third metacarpals with the wrist and forearm. The wrist extensors and flexors fire simultaneously to stabilize the wrist at impact.

We have had the opportunity to treat a large number of so-called “boxing injuries” caused by contact with other “boxers,” as well as inanimate objects such as walls. The majority of the injuries occur to the fifth and occasionally fourth metacarpals and are due to poor punching technique. Contact with these metacarpal heads results in almost no energy transfer to the target and occasional severe injury to the boxer’s hand. Common sense explains why avulsion fractures of the second and third metacarpals are rare. Most people who sustain a fall do so with an outstretched hand and not a clenched fist, resulting in an extension injury. The patient in our case sustained his injury by hitting appropriately with the second and third metacarpal heads; however, at the point of impact, the patient sustained a forceful flexion of the wrist. This put a strong eccentric load on the extensor carpi radialis brevis, which was strong enough to avulse a fragment of bone from the base of the third metacarpal.

References

1. Cobbs KF, Owens WS, Berg EE. Extensor carpi radialis brevis avulsion fracture of the long finger metacarpal: a case report. J Hand Surg Am. 1996; 21(4):684-686.
2. Tsiridis E, Kohls-Gatzoulis J, Schizas C. Avulsion fracture of the extensor carpi radialis brevis insertion. J Hand Surg Br. 2001; 26(6):596-598.
3. Boles SD, Durbin RA. Simultaneous ipsilateral avulsion of the extensor carpi radialis longus and brevis tendon insertions: case report and review of the literature. J Hand Surg Am. 1999; 24(4):845-849.
4. Rotman MB, Pruitt DL. Avulsion fracture of the extensor carpi radialis brevis insertion. J Hand Surg Am. 1993; 18(3):511-513.
5. Johnson AE, Puttler EG. Avulsion of the extensor carpi radialis brevis insertion: a case report and review of the literature. Mil Med. 2006; 171(2): 136-138.

Authors

Drs Breeze and Mays are from the Richmond Bone and Joint Clinic, Richmond, Texas; Mr Ouellette is from Texas State University, San Marcos, Texas.

Correspondence should be addressed to: Matthew M. Mays, MD, Richmond Bone and Joint Clinic, 15035 Southwest Freeway, Sugar Land, TX 77478.