A Boxer’s fracture is a common hand injury involving a break in the metacarpal bones. This injury most frequently affects the neck of the fifth metacarpal, the bone leading to the little finger. The name comes from the typical mechanism of injury, which is an axial load caused by striking a hard, immovable object with a closed fist. Treatment for this fracture is guided by the injury’s specific severity and alignment.
Identifying the Injury and Initial Assessment
Treatment begins with a thorough physical examination and diagnostic imaging. A healthcare provider will inspect the hand for signs like swelling, bruising, and tenderness. A loss of the normal prominence of the knuckle, often described as a depressed knuckle, is a common physical sign of this particular fracture.
The most concerning aspect is rotational deformity, which occurs when the injured finger overlaps or “scisors” over the adjacent finger when a fist is made. This malrotation must be corrected to maintain proper hand function. X-rays are then used to confirm the diagnosis and measure the degree of bone displacement and the angulation, or bend, of the fractured metacarpal neck.
These X-ray measurements are the primary criteria for deciding the next steps in treatment. For the fifth metacarpal, a degree of volar angulation—where the bone fragment bends toward the palm—is typically acceptable due to the natural mobility of the fourth and fifth metacarpals. However, angulation exceeding a range of 40 to 70 degrees often indicates the need for intervention to realign the bone.
Non-Surgical Management and Stabilization
Most Boxer’s fractures are treated successfully using non-surgical methods, especially when the angulation is within the acceptable limit and there is no rotational deformity. If the angulation is deemed too great, a procedure called closed reduction is performed to realign the bone fragments without making an incision. This is typically done under a local anesthetic or sedation to manage pain and relax the muscles.
During a closed reduction, the physician uses a technique often referred to as the 90-90 method, flexing the finger joints to manipulate the bone back into its correct position. Once the bone is aligned, the hand is immobilized using a cast or an ulnar gutter splint, which includes the little and ring fingers.
The hand must be stabilized in a specific position known as the “safe position” or “intrinsic-plus” position. This involves flexing the metacarpophalangeal (MCP) joints—the knuckles—to 70 to 90 degrees while keeping the interphalangeal joints, the smaller finger joints, straight. This positioning prevents the collateral ligaments of the MCP joints from shortening, a complication that causes long-term joint stiffness. Follow-up X-rays are taken within the first one to two weeks to ensure the fracture remains stable and has not shifted out of alignment.
Surgical Intervention and Criteria
Surgery is reserved for a small percentage of cases where the fracture is unstable or severely displaced. Primary indications include an open fracture or when there is a significant rotational malalignment that cannot be corrected otherwise.
Excessive angulation or shortening of the bone is another criterion for surgery. Most surgeons considering angulation over 40 degrees or shortening greater than 5 millimeters as unacceptable. For these unstable fractures, the goal of surgery is to rigidly fix the bone fragments to prevent movement during the healing process.
Two common surgical techniques are employed for fixation. Closed reduction and percutaneous pinning involves realigning the fracture and then inserting thin metal wires, called Kirschner or K-wires, through the skin to hold the bone in place. Alternatively, Open Reduction and Internal Fixation (ORIF) requires an incision to directly visualize the fracture, realign the fragments, and secure them with small plates and screws. The choice between these methods depends on the complexity of the fracture pattern and the surgeon’s preference.
Recovery Timeline and Physical Therapy
The initial healing phase for a Boxer’s fracture involves immobilization in a splint or cast for approximately three to six weeks. During this period, the goal is to protect the bone while the natural healing process, which includes the formation of a soft and then hard callus, takes place. Once the bone is clinically stable and sufficient healing is confirmed by X-ray, the immobilization device is removed.
The post-immobilization phase requires a rehabilitation program, as stiffness is a common consequence of being unable to move the hand for several weeks. Physical therapy focuses initially on restoring the full range of motion in the fingers and wrist.
As mobility improves, the program progresses to strengthening exercises to rebuild grip strength and hand function. Full recovery, allowing a return to strenuous activities or sports, usually takes between three and four months, depending on the severity of the original injury and the patient’s adherence to the physical therapy regimen.