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Dislocations And Subluxations

The terms dislocation and subluxation refer to the displacement from their normal position of bones that form a joint. These displacements most often result from injury, causing adjoining bones to no longer align with each other. A partial or incomplete dislocation is called a subluxation.

In a dislocation, joint bones are displaced so that their articulating surfaces totally lose contact. Subluxations partially displace the articulating surfaces.

Dislocations and subluxations occur at the joints of the shoulders, elbows, wrists, digits, hips, knees, ankles, and feet; the injury may accompany fractures of these joints or result in deposition of fracture fragments between joint surfaces. Prompt reduction can limit the resulting damage to soft tissue, nerves, and blood vessels.

Causes

A dislocation or subluxation may be congenital (as in congenital dislocation of the hip), or it may follow trauma or disease of surrounding joint tissues (for example, Paget's disease).

Signs and symptoms

Dislocations and subluxations produce deformity around the joint, change the length of the involved extremity, impair joint mobility, and cause point tenderness.

When the injury results from trauma, it's extremely painful and often accompanies joint surface fractures. Even in the absence of concomitant fracture, the displaced bone may damage surrounding muscles, ligaments, nerves, and blood vessels and may cause bone necrosis, especially if reduction is delayed.

Diagnosis

A thorough medical history and physical exam by a physician is the first step in the correct diagnosis of dislocations and subluxations. X rays of the joint and adjacent bones can locate and help determine the extent of dislocated joints.

Treatment

Immediate reduction (before tissue edema and muscle spasm make reduction difficult) can prevent additional tissue damage and vascular impairment.

Some injuries require open reduction under regional block or general anesthesia. Such surgery may include wire fixation of the joint, skeletal traction, and ligament repair.

After reduction, a splint, cast, or traction immobilizes the joint. Generally, immobilizing the digits for 2 weeks, hips for 6 to 8 weeks, and other dislocated joints for 3 to 6 weeks allows surrounding ligaments to heal.

Prevention

When an individual is involved in strenuous sports or heavy work, involved joints may be protected by elastic bandage wraps, tape wraps, knee and shoulder pads, or special support stockings. Keeping the muscles surrounding the joint strong will also help prevent dislocations. Long-term problems may also be prevented by allowing an adequate amount of time for an injured joint to rest and heal prior to resuming full activity.