Boxer's fracture

Boxer's fracture
Classification and external resources
DP (PA) right hand x-ray showing fracture at the neck of fourth metacarpal bone
ICD-10	S62.3
eMedicine	aaem/53

A Boxer's fracture (bar room's fracture) is a fracture of the fourth and/or fifth metacarpal bones transverse neck secondary to an indirect force such as striking an object with a closed fist due to axial loading.^[1]

Signs and symptoms

The symptoms are pain and tenderness in the specific location of the hand, which corresponds to the metacarpal bone around the knuckle. When a fracture occurs, there may be a snapping or popping sensation. There will be swelling of the hand along with discoloration or bruising in the affected area. Cuts on the hand are also likely to occur. Movement of the bone may be limited due to the fracture and pain may be inflicted if movement occurs in the specified area. Lastly there could be a misalignment of the finger.

Causes

Boxer’s fractures are usually caused by the impact of a clenched fist with a skull or a hard, immovable object, such as a wall.^[2] The knuckle of the ring finger tends to lead the rest of the knuckles in a hard punch, and the knuckle compresses and snaps the neck of the metacarpal bone. When a boxer punches with proper form, the knuckles of the second and third metacarpal align linearly with the articulating radius, followed linearly by the humerus. As a proper punch makes contact, the force should travel from the rotating body across the humerus, straight across the radius, straight across the second and third metacarpals, finally transferring all the momentum and force from the respective knuckles to the point of contact. Due to the linear articulation of bones, the force is able to travel freely across these joints and bones. However, improper form causes the break to occur at an angle towards the palm, creating a dorsal bump, which ultimately causes the fracture, as the knuckle of the index finger tends to lead the rest of the knuckles in a hard punch, and the knuckle compresses and snaps the neck of the metacarpal bone.^[3]

Anatomy

There are 27 bones in the hand and wrist together, 5 of which are called the metacarpals. The metacarpals lie in the region between the proximal phalange bones and the carpal bones. Boxers fracture generally occurs in the 4th and/or 5th metacarpal of the hand.^[4] More specifically, the fracture happens in the neck region in the distal end of the metacarpal. The bone itself is located between the joints called the metacarpophalangeal joint and the carpometacarpal joint. The fracture occurs just below the head of the metacarpal which is the neck region of the metacarpal.^[5] The neck is the most susceptible and prone to breaks because it is the most fragile part of the metacarpal.^[6]

Diagnosis

Diagnosis by a doctor’s examination is the most common, accompanied most often by x-rays. X-ray is used to display the fracture and the angulations of the fracture. A CT scan may be done in very rare cases to provide a more detailed picture.

Prevention

Boxers and other combat athletes routinely use hand wraps and boxing gloves to help stabilize the hand, greatly reducing pain and risk of injury during impact training such as working the heavy bag. Hand wraps are made with typical athletic tape. Proper punching form is the most important factor to prevent this type of fracture.

Treatment

Once injured, the subject will feel both the swelling and associated pain in the hand. To temporarily help alleviate the pain and swelling, ice must be applied. If there are any open wounds, washing the hand is advised to avoid any sort of infections. Before seeing a physician, the injured hand must remain immobilized and cannot be used to complete tasks. If the broken hand is used, it can cause further damage to the muscles, blood vessels, tendons, ligaments and nerves. It is advised to help with the pain; the subject can take over the counter drugs, such as acetaminophen or ibuprofen. Some splints would extend from the about the mid-forearm to the fingers, leaving the fingertips exposed. If the injury isn’t bad, doctors can recommend using tape. Here, the finger is taped to the adjacent finger together, helping limited mobilization. The doctor will recommend what works best, depending on the condition of the injury.

A conservative approach to healing can be attempted for cases with only minor angulation. Angulation is the misalignment of the metacarpal bones. If the injury causes angulation in the 2nd or 3rd metacarpal, this can lead the subject to visiting a hand specialist, where surgery can be a possibility. The surgeons look to see if the bone surpasses 70 degrees. Surgery is recommended if the bones are badly misaligned and the doctor is unable to correct the bones by pulling or pushing. In the surgery, they will place many pins through both parts of the bones so that the bone will heal correctly. Initial reduction is optimally performed by the Jahss maneuver, in which the metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) are flexed to 90 degrees, causing reduction by tightening of the collateral ligaments of the MCP.^[7] Subsequent splinting is performed with the MCP joint remaining flexed to avoid tendon contracture.^[7]

Severe angulation requires pins to be put in place and realignment as well as the usual splinting. However, the prognosis on these fractures is generally good, with total healing time not exceeding 12 weeks. The first two weeks will show significantly reduced overall swelling with improvement in clenching ability showing up first. Ability to extend the fingers in all directions appears to improve more slowly. Hard casts are rarely required and soft casts or splints can be removed for brief periods of time to allow for activities such as showers and "airing out" the cast or splinted area so as to avoid skin rotting and permit cleansing of the cast or splinted area.^[8] Pain from this injury is generally very mild and rarely requires medications beyond over the counter drugs such as ibuprofen or acetaminophen. Muscle atrophy in isolated areas of 5 to 15 percent should be expected with a rehabilitation period of approximately 4 months given adequate therapy. In the mildest of cases, full rehabilitation status can be achieved within 3 to 4 months.

For smaller angled fractures most discomfort is alleviated by raising the fracture above the heart; after swelling has subsided, if there is no cast, warm water can be used to relieve some of the pain. It is important that when the cast is removed that the hand is gently exercised by attempting the common functions in the hand.

Epidemiology

Hand and wrist injuries are reported to account for fifteen to twenty percent of emergency room injuries. Boxer’s fractures represent a significant number of those injuries. Trends have been found in multiple studies, showing a positive relationship between boxer’s fractures from intentional closed fist injuries, and psychological disorders. Although males are nearly fifty percent more likely to sustain fracture from a punch mechanism than females, who account for just over ten percent; male punch injuries are correlated predominantly with social deprivation instead of psychiatric disorders like that of their female counterparts. Boxer's fractures represent over one half of all metacarpal fractures.^[9] Hand injuries of this sort are most prevalent among fifteen to thirty-five year-old males. The right hand is injured as frequently as the left. The fifth metacarpal is the most frequent reported fractured metacarpal. Seasonal variability in the incidence of hand fractures does not seem to have any relevance.^[10] Approximately 3.7 male hand injuries, per 1000, per year, and 1.3 female hand injuries, per 1000, per year, have been reported. Common mechanisms of injury are gender specific. Although the fiscal cost is not available, it can be asserted that the cost is reasonably significant per individual, depending on the cost of emergency care, immobilization, surgery, follow up doctors’ visits, etc. in addition to the fiscal impact from loss of and/or limited work abilities.

References

Anakwe, R. E., Aitken, S. A., Cowie, J. G., Middleton, S. D., and Court-Brown, C. M. 2010. The epidemiology of fractures of the hand and the influence of social deprivation. Journal of Hand Surgery, European Volume, 36(1), pp. 62–65.

Bragg, S. 2005. The Boxer's Fracture. Journal of Emergency Nursing, 31(473).

Greer, S. E., and Williams, J. M. 1999. An indicator of intentional and recurrent injury. American Journal of Emergency Medicine, 17(4), pp. 357–360.

Bracker, M. D., Rice, E. L., Yassini, P. 2001. The 5-minute sports medicine consult, pp. 110. Lippincott, Williams & Wilkins, Philadelphia, PA.

Altizer, L. 2006. Boxer's Fracture. Orthopedic nursing journal, 25(4), pp. 271–273.

External links

Wikimedia Commons has media related to X-rays of boxer fractures.

• http://www.med.umich.edu/1libr/sma/sma_meta5car_art.htm
• http://www.wheelessonline.com/ortho/boxers_fracture_metacarpal_neck_1