A dislocation is an injury in which the normal relationship between the articulating bones of a joint is completely or substantially lost, causing the joint surfaces to move out of their normal position. A partial displacement is generally called a subluxation rather than a complete dislocation. Dislocations most commonly occur when a force pushes a joint beyond its normal range, such as during a fall, collision, twisting movement or direct impact.
The shoulder is particularly susceptible because it combines substantial mobility with relatively limited bony constraint, but dislocations can occur in many joints including the elbow, finger, hip, knee and patella. A dislocation can damage not only the joint surfaces but also surrounding ligaments, capsule, cartilage, tendons, muscles, nerves and blood vessels. It is therefore more than a simple movement abnormality and can represent a significant acute injury requiring prompt medical assessment.
The anatomy of the affected joint determines how a dislocation occurs and what structures are vulnerable. A joint is stabilised through a combination of bone shape, joint capsule, ligaments, muscles, tendons and neuromuscular control. When an external force or muscle generated force exceeds the stabilising capacity of these structures, one bone can move relative to another beyond its normal anatomical position. Some joints have a greater range of motion and therefore rely more heavily on soft tissues for stability. After a first dislocation, damage to stabilising structures can sometimes increase the likelihood of recurrence, particularly in certain joints and activities. Repeated instability can become a major sporting problem because rapid movement and contact can repeatedly challenge joint stability.
A dislocation often produces severe pain, visible or palpable deformity and substantial restriction of movement. The affected limb or joint may appear to be in an abnormal position, and the person may be unable or unwilling to move it because of pain. Swelling can develop rapidly, and associated nerve or blood vessel damage may cause numbness, weakness, altered colour or reduced circulation. These complications make a suspected dislocation a medical problem rather than an injury that should be forcefully corrected by an untrained person. The NHS advises emergency assessment for injuries involving major deformity, abnormal sensation or colour changes because such findings can indicate serious structural or neurovascular damage.
Diagnosis normally involves physical examination and imaging. X rays are frequently used to confirm the position of bones and identify associated fractures, while additional imaging may be appropriate for selected injuries or recurrent instability. The clinician must establish not only whether the joint is dislocated but also whether nerves, blood vessels, bones, cartilage or other soft tissues have been damaged. A dislocation associated with a fracture can require different treatment from an isolated dislocation. After assessment, the joint may need reduction, meaning that the bones are carefully returned to their normal anatomical relationship. Reduction should be performed by appropriately trained healthcare professionals because forceful or inappropriate manipulation can worsen fractures or damage nerves and blood vessels.
Once the joint has been reduced, treatment focuses on protecting the injured structures while restoring normal movement and stability. Depending on the joint and injury, this may involve a period of immobilisation followed by physiotherapy. Rehabilitation can address range of motion, muscle strength, proprioception and sport specific control. The correct balance is important because excessive immobilisation can produce stiffness and weakness, while excessive movement too early can aggravate healing structures. The exact rehabilitation pathway depends on the joint, age, sporting demands, recurrence history and associated injuries. Some first time dislocations recover satisfactorily with non operative management, while recurrent instability or particular structural injuries may lead to consideration of surgery.
Dislocations are particularly important in sport because athletes often depend on rapid, controlled movement and high joint stability. A shoulder dislocation can affect throwing, contact and overhead activities, while a patellar dislocation can interfere with running, jumping and directional changes. A recurrently unstable joint may create apprehension during movements that previously caused injury, potentially changing movement patterns. Rehabilitation therefore needs to restore not only strength but confidence, coordination and the ability to control the joint under realistic sporting loads. Return to sport should be guided by recovery of function and stability rather than simply by the number of days since reduction.
A dislocation differs from a fracture because a dislocation primarily concerns loss of normal joint alignment, although fractures can occur at the same time. It differs from a ligament sprain because a sprain describes ligament damage, whereas a dislocation describes abnormal joint positioning; nevertheless, ligament damage frequently accompanies dislocation. It differs from a subluxation because subluxation refers to incomplete displacement. These terms can coexist in one injury description, such as a dislocation accompanied by ligament rupture and a fracture. Correct terminology is therefore important because the same traumatic event can damage several anatomical structures simultaneously.
A dislocation should be treated as an injury requiring appropriate medical assessment, particularly when deformity, severe pain, altered sensation, abnormal colour or inability to move the joint is present. Attempting to relocate a joint without appropriate training can create additional injury. Once treated, long term management depends on the joint and the extent of structural damage. Prevention can involve strength, neuromuscular control, appropriate technique and sport specific conditioning, but previous dislocation is itself relevant because recurrent instability can occur. The central concepts are loss of joint congruence, associated tissue damage, safe reduction, neurovascular assessment, rehabilitation and restoration of stability before full sporting participation.
