Doctor of Medicine, specialist in the Japanese Society of Rehabilitation Medicine, specialist in the Japanese Society of Orthopaedic Surgery, specialist in the Japanese Society of Rheumatology, staff to strengthen JOC, and sports physician certified by the Japan Sports Association
Boxer's fracture is a sports disorder that occurs in the fist .
Boxer’s fracture is one of the sports injuries that develop fractures of metacarpal bones on the hand caused by throwing a strong fist impact (knuckle) (Fig. 1).
Figure 1: Boxer’s fracture injury occurs at the moment of punching.
Photo 1: A hand after punching with impact
Photo 2: X-ray picture of a boxer’s fracture
Cause and mechanism of onset
When the person performs fore fist punch, a force is applied to the metacarpal bone in the longitudinal direction, but a slight shift in the direction of the impact may add impact on the metacarpal neck, and even long bones may also be fractured.
The injuries are more likely to occur at the necks of the fourth and fifth metacarpal bones. Hard punchers may fracture the second and third metacarpal bones, and a fracture of the thumb may also occur if they do not make a fist properly.
Severe pain, swelling, deformity and impaired movement of the fingers occur rapidly after impact of punch (Photo 1).
There is a fracture line in the neck of the metacarpal bone, which presents a flexion deformity of the dorsal spur (Photo 2). This deformity occurs due to bone dislocation by action of the interosseous muscles, flexor digitorum tendons and extensor carpi.
Treatment and rehabilitation
The dorsal spur is more likely to be deformable in the metacarpal neck, and conservative treatment consists of correcting, reducing and fixing the deformity with the metacarpophalangeal (MP) and proximal interphalangeal (PIP) joint at a 90-degree of flexion; in fact, the deformity tends to reoccur. Where reduction is difficult, surgery is suitable for the treatment. Internal fixation, such as percutaneous steel wire insertion, is indicated.
Fixation with conservative treatment takes 4 to 6 weeks. Then, the person is able to start doing flexion and extension exercise of the fingers. Additional fixation period is required for boxers. If complete synostosis is identified on the X-ray at least 2 months later, the patient may try to tap by the fist a soft thing properly and lightly. In case of deformity or shortening, fractures are more likely to reoccur. Therefore, the patient requires a longer period to heal. Exercise applying a strong punch with impact should be prohibited for 6 months.
It is said that Hiroyuki Ebihara, the former World Flyweight boxing champion, used to get his own fist damaged due to the great force of his punch. He suffered from fractures several times during playing days, and the fractures did not recover completely. Finally that led to his retirement. Boxer’s fracture could be a fatal injury for a hard puncher.
Associate Professor, the Department of Regional Medicine, Teikyo Heisei University
A certified athletic trainer from the Japan Sport Association, a practitioner of acupuncture and a massage practitioner
Mechanism of injury and on-site treatment
Boxer’s fracture occurs when the fist is clenched and a strong punch is thrown, resulting in fractures of the neck of the metacarpal bone. In general, the fractures occur most often in the fourth and fifth metacarpal bones. However, senior athletes, such as professional boxers and Karate practitioners, often get injured on the second and third metacarpal bones, so they need to be cautious in sports scenes. If a doctor confirms limitation of MP joint motion and loss (deformity) of a prominent metacarpal head or severe swelling of the metacarpal neck as acute symptoms, the doctor suspects fractures and treats the injuries.
On-site evaluation and first aid
First on-site treatment is icing. If there is deformity caused by the fractures, it is recommended to use ice bucket because compressing the region with ice packs or ice bags may be painful. At the time, the injured area should be elevated as much as possible with the ice bucket positioned in high level. Also, doing icing on the whole hand by dipping the hand getting to the position of wrist in the bucket. Once the hand becomes numb in 20 minutes, the area needs to be immobilized.
Fixation is performed using a splint with sponge attached to a metal plate (Photo 2). As the splint may be easily deformed by hand, it provides firm fixation on the injured area. The splint is very useful in the first-aid treatment at the sports scene.
The splint is placed on the volar side and taped around the wrist and DIP joint. The MP joint is fixed in a slightly flexed position. Once fixation is done, the patient has to seek medical attention immediately.
For conservative treatment, the injured area is immobilized for 3 to 4 weeks after reduction at the medical institution.
After fixation, athletic rehabilitation is provided for the purpose of restoring range of motion and muscle strength. An introduction of an athletic rehabilitation program is introduced as follows.
Massage of the back of the hand
Initially, physical therapy such as warm bath method and hot pack is provided, followed by passive approaches to massage or exert traction on to improve joint contractures.
Kneading the area between metacarpals with thumb
Kneading the finger with two-finger
Improvement of Joint Range of Motion by the hand
MP joint flexion
MP joint extension
Next, active exercises and strength training are performed, and try to move the affected area actively. The decision to return to competition is made by reviewing the condition of synostosis and recovery of joint function.
Active exercise with buddy tape
By using buddy tapes, the injured finger may be exercised simultaneously with the movement of approximal finger.
Flexion of MP, PIP and DIP joint
Extension of MP, PIP and DIP joint
Finger abduction with rubber band as a load
Holding by pulling on elastic bandage or towel in hand