A Boxer’s fracture is a common injury involving a break in one of the long bones of the hand, known as the metacarpals. This specific fracture is named for the typical way the injury occurs, though it is not exclusive to combat sports. It most frequently affects the fifth metacarpal (little finger) but can also involve the fourth metacarpal (ring finger). Metacarpals form the framework of the palm, and their proper alignment is necessary for effective hand function.
Location and Common Causes
The fracture almost always occurs in the neck of the metacarpal, the narrow part of the bone just below the knuckle. This location is vulnerable because the force is concentrated there upon impact. The smaller diameter of the fourth and fifth metacarpal bones makes them more susceptible to this injury. The primary mechanism is axial loading, a force applied along the long axis of the bone. This typically happens when striking a hard surface with a clenched fist, causing the force to transmit through the knuckle and fracture the bone at its neck.
Recognizing the Signs of a Fracture
The immediate aftermath of a Boxer’s fracture involves several clear physical signs centered around the injured knuckle. Acute pain is localized over the affected metacarpal bone, and the area quickly develops swelling and bruising (ecchymosis). The most characteristic visual sign is the loss of the normal knuckle contour, where the injured knuckle appears sunken or depressed when making a fist. Rotational deformity is another important sign; when attempting to make a fist, the little finger may cross over or under the adjacent ring finger. X-rays are used to confirm the diagnosis and determine the degree of angulation and displacement of the broken bone fragments.
Treatment Options and Healing Timeline
Treatment depends on the severity of displacement and the degree of angulation of the bone fragments. Non-surgical management is sufficient for minimally displaced fractures or those with acceptable angulation. For the fifth metacarpal, angulation up to 40 degrees is often accepted due to the joint’s natural mobility. If bone fragments are significantly misaligned, non-surgical treatment begins with closed reduction, where a professional manipulates the bone back into position without an incision. Following reduction, the hand is immobilized using an ulnar gutter splint or cast, which is typically applied with the knuckles flexed to about 70 degrees to maintain the corrected position.
Surgical intervention, known as open reduction and internal fixation (ORIF), is reserved for more severe cases. Surgery is necessary when angulation exceeds 40 to 45 degrees or if there is significant rotational deformity that cannot be corrected otherwise. This procedure involves an incision to realign the bone fragments, which are then fixed in place using small plates, screws, or pins. Bone union typically ranges from four to eight weeks, depending on the fracture’s severity. After immobilization, physical or occupational therapy is necessary to restore full range of motion and strength in the hand and fingers.