A Boxer’s fracture is a common hand injury involving a break in the neck of the fifth metacarpal bone, the long bone leading to the little finger. While the name suggests a fighting injury, it frequently results from punching any hard object with a closed fist. Treatment varies significantly, depending on the fracture’s stability and the degree of bone displacement.
Understanding the Injury and Diagnosis
The metacarpals are the five long bones in the hand, and a Boxer’s fracture occurs just below the knuckle joint, at the narrowest part known as the neck. When the hand strikes an object, the force causes the bone to break and the head of the metacarpal to angulate toward the palm. This injury is common, representing about 20% of all hand fractures.
Symptoms typically include immediate pain, rapid swelling, and bruising near the pinky finger. A visible sign is often a “sunken” or flattened appearance of the knuckle due to the displaced metacarpal bone. The affected finger may also appear misaligned or rotated when the patient attempts to make a fist.
Diagnosis begins with a physical examination, where the doctor assesses tenderness and checks for rotational deformity. X-rays are necessary to confirm the fracture and determine its severity, usually including an AP, oblique, and lateral view. These images precisely measure the degree of angulation, shortening, and displacement, which are the main factors guiding the treatment decision.
Conservative Management Options
Most Boxer’s fractures are stable and do not require surgery, making conservative treatment the standard first-line approach. The goal of non-surgical management is to reduce pain and ensure the bone heals in a position that maintains functional alignment. For fractures with acceptable angulation and no rotational deformity, initial management focuses on immobilization.
If the angulation is significant, a procedure called closed reduction may be performed. The doctor manually manipulates the bone fragments back into an acceptable position without making an incision. Following reduction, the hand is immobilized using a splint or cast. The ulnar gutter splint is common, positioning the wrist and fingers to maintain the corrected alignment.
For many uncomplicated fractures with angulation up to 70 degrees, a shorter period of immobilization is often favored, sometimes followed by immediate, gentle mobilization. The typical healing time requires the splint or cast to be worn for three to four weeks, followed by protective splinting for up to six weeks. Functional outcomes are excellent, often allowing an earlier return to daily activities compared to surgical cases.
Criteria for Surgical Intervention
Surgery is generally reserved for a minority of Boxer’s fractures that are unstable or severely displaced. The decision is based on specific measurements of angulation, rotation, and other characteristics of the break.
A primary concern is excessive angulation, the degree to which the metacarpal head bends toward the palm. While the fifth metacarpal can tolerate a high degree of angulation without significant functional loss, surgery may be indicated if the angulation exceeds a certain threshold, often cited as greater than 40 to 70 degrees. Excessive shortening of the metacarpal bone, typically more than five millimeters, can also prompt surgical consideration.
Rotational deformity is a particularly important indication for surgery because it can lead to “scissoring” of the fingers when making a fist, which severely impairs hand function. Unlike angulation, even slight rotational malalignment is poorly tolerated and usually necessitates an operation. Other indications for surgery include open fractures, where the bone has broken through the skin, or if the fracture is unstable after a closed reduction attempt.
What Happens During and After Surgery
When surgical fixation is necessary, the goal is to stabilize the bone fragments securely to allow for healing in the correct alignment. Several surgical techniques are employed, tailored to the specific fracture pattern.
A common method is Closed Reduction and Percutaneous Pinning, where the surgeon repositions the bone fragments and inserts small metal wires, known as K-wires, through the skin to hold the bone in place.
Another technique is Open Reduction and Internal Fixation (ORIF), which involves making an incision to visualize the fracture, realign the bones, and secure them with plates and screws. K-wires may be removed after the bone begins to heal, typically a few weeks later, while plates and screws are often left in permanently. Following the procedure, the hand is immobilized for a period, and physical therapy is required. Rehabilitation focuses on restoring the full range of motion and strength. The overall recovery period is usually longer than non-surgical treatment, often taking six to ten weeks for full union.