Thumb Fractures

The thumb plays a major role in the critical functions of the hand. The thumb is needed for grasping, pushing, and pulling. Injuries to the thumb can dramatically reduce function, and injuries to the joint can result in painful and stiff arthritis of the thumb.

Anatomy

There are three major bones in the thumb: the first metacarpal, which is the long bone in the thumb coming from the hand to the base of the finger; the proximal phalanx; and distal phalanx, which contains the thumb nail.

There are tendons that control the movement of the thumb to bend the thumb, straighten the thumb, and the reach the thumb across the palm.

Causes

Fractures can occur when enough force is applied to the bones. Common injuries include:

• Punching an object or person
• Accidents involving power saws or drills
• Falling and catching the fall with hands to the ground
• Jamming a finger while catching a ball
• Car or bicycle accidents
• Gunshot wounds

Types of Fractures

There are different characteristics of fractures which help us to determine the severity. Fractures can break in a straight line, in a spiral pattern, split into multiple pieces, or completely shattered. Fractures that extend into the joint may cause future stiffness, arthritis, and pain. Fractures associated with open wounds increase the risk for infections that may get deep into the bone. Fractures can also be associated with ligament injuries which are soft tissues that cause the bones to bend or straighten.

Two common types of fractures involving the carpometacarpal joint (CMC joint) is the joint between the hand and the thumb:

• A Bennett fracture is at the base of the thumb metacarpal involving the CMC joint. These fractures usually involve a clean break with two significant pieces of bone on either side of the fracture.
• A Rolando fracture is similar to a Bennett fracture but with more broken pieces or fractures at the base of the first metacarpal. The fractures may create a T or Y-shaped pattern.

Misalignment of the fracture at the joint surface is an indication for surgical repair to restore the positioning of the fracture pieces.

Treatment

Non-Operative or Conservative:

If the fracture pattern is overall well-aligned without much deformity, it may heal well without surgery. Splints or casts may position the injury while the bone is healing. Typically x-rays are performed periodically to assess the positioning and healing of the fracture. Once the bones have healed, occupational or physical therapy may be helpful in restoring range of motion, strength, and function.

Operative

Severe fractures or fractures with significant deformity may require surgery to restore the bones to their original position. Fractures that extend into the CMC, CMP, or IP joints are more complex and may warrant surgery to reduce the risk of painful arthritis. Fractures may be associated with tendon or ligament injuries which may require surgery to reconstruct to restore function. Devices such as pins, plates, screws, and wires, may be used to keep the fracture in the proper alignment while the bones heal. Sometimes, these devices may be removed once the fracture is healed. X-rays are used to evaluate the healing process. In some cases, having surgery may allow for early motion which helps to prevent stiffness in the hand and fingers.