A joint dislocation occurs when the bones forming a joint are forced out of their normal alignment, often causing significant soft tissue damage. The human hand, with its twenty-seven intricate bones, is highly susceptible to these injuries, which can occur anywhere from the wrist down to the fingertip. Dislocations are common, typically resulting from sudden trauma that pushes the joint beyond its natural range of motion. Understanding the specific joints involved and the necessary steps following an injury is important for ensuring the best possible recovery.
Anatomy of Hand Dislocation
The hand involves several distinct groups of joints susceptible to dislocation. The long bones of the fingers (phalanges) are connected by interphalangeal (IP) joints, the most frequent sites of dislocation. Each finger has two IP joints: the proximal interphalangeal (PIP) joint (the middle joint) and the distal interphalangeal (DIP) joint (near the fingertip). The PIP joint is the most commonly dislocated joint, typically bending backward in a dorsal direction.
The knuckles, known as the metacarpophalangeal (MCP) joints, connect the finger bones to the metacarpal bones in the palm. MCP dislocations often affect the thumb and are more difficult to reduce than finger dislocations. Closer to the wrist are the carpometacarpal (CMC) joints, which link the metacarpals to the small wrist bones.
The wrist contains eight small carpal bones, which can also dislocate, though less frequently than finger joints. Carpal bone dislocations, such as the lunate, usually result from high-energy trauma and are considered complex injuries. These anatomical structures rely on strong ligaments, which are often stretched or torn during a dislocation, causing instability.
Causes and Signs of a Dislocation
Hand dislocations are caused by a significant external force that abruptly displaces the joint surfaces. A common mechanism for finger dislocations is axial loading or hyperextension, such as catching a ball that forcefully jams the fingertip. High-impact sports, including football, basketball, and baseball, account for a large number of these injuries, particularly affecting the IP joints.
Dislocations can also result from a fall onto an outstretched hand, which frequently causes injuries to the MCP and CMC joints. Motor vehicle crashes or serious work-related accidents can generate enough force to dislocate the wrist bones. Regardless of the cause, a dislocated joint will present with immediate, severe pain.
The appearance of the hand offers the most recognizable sign, as the joint will look visibly crooked, misshapen, or out of place. Swelling and bruising around the injured area develop rapidly, and the individual will experience difficulty or a complete inability to move the affected digit. Nerve involvement from the trauma can also cause numbness or a loss of sensation in the hand or finger.
Immediate Steps After Injury
If a hand dislocation is suspected, seek immediate professional medical attention, ideally at an emergency room or urgent care facility. Avoid the impulse to manually push the joint back into place. Attempting to reset the bones without medical training can cause further damage to soft tissues, including ligaments, tendons, and nerves.
While waiting for medical help, keep the hand as still as possible to prevent further injury. The joint can be carefully immobilized using a makeshift splint or by taping the injured finger to an adjacent, uninjured finger (buddy taping). Applying a cold compress or ice pack wrapped in a cloth helps minimize swelling and reduce pain.
If the injury involves the hand or wrist, remove any rings, watches, or jewelry immediately before swelling begins. Keeping the injured hand elevated above the heart also assists in decreasing swelling. These initial steps stabilize the injury and prepare the patient for safe treatment.
Medical Treatment and Healing Process
Upon arrival at a medical facility, treatment begins with a physical examination followed by X-rays taken from multiple angles. X-rays confirm the diagnosis and check for associated fractures, as displaced bones often occur alongside a break. Once assessed, the joint must be realigned through a procedure called reduction.
For most finger dislocations, a doctor performs a closed reduction, manually manipulating the bones back into position without a surgical incision. This procedure is usually performed after injecting a local anesthetic for pain management. If closed reduction is unsuccessful, often due to a trapped ligament or tendon blocking the joint space, an open reduction (surgery) is required to realign the bones.
Following a successful reduction, the joint is immobilized using a splint or cast for several weeks to allow damaged ligaments and soft tissues to heal. A dislocated finger may require immobilization for about three weeks, while complex wrist dislocations can necessitate a cast for up to eight weeks. Recovery almost always includes physical therapy to restore strength and maximize range of motion, as stiffness is a common complication.