The phrase “joints keep going out” medically describes recurrent joint instability, which involves a partial or complete loss of alignment between the bones of a joint. A partial displacement, where the joint surfaces remain somewhat in contact, is called a subluxation. When the bones fully separate, it is a complete dislocation. Chronic instability means these events happen frequently, sometimes with minimal force or even spontaneously. This recurrence indicates a structural or functional problem that prevents the joint from maintaining its proper position.
The Physical Process of Joint Instability
Joint stability relies on a complex interplay between static and dynamic restraints that hold the bones in alignment. Static restraints are non-contractile structures, primarily the joint capsule and the strong bands of connective tissue known as ligaments. Ligaments restrict excessive movement and prevent the joint surfaces from separating. When these structures are stretched or torn, they become lax and lose their ability to provide passive stability.
Instability occurs when lax static restraints allow the joint to move beyond its physiological limit, causing the bones to shift out of place. Dynamic restraints—the surrounding muscles and their tendons—provide active support and help control joint position. If static structures are damaged, dynamic restraints must compensate; if they fail, the joint surfaces will separate, resulting in subluxation or dislocation.
Chronic Causes: Structural and Genetic Predisposition
Chronic joint instability can stem from inherent anatomical or genetic factors. Generalized joint hypermobility is a common predisposition where a person has naturally looser ligaments and tendons. This laxity is frequently linked to variations in the genes responsible for producing collagen, the protein that provides strength and flexibility to connective tissues.
While hypermobility is often benign, it can be a feature of heritable disorders of connective tissue (HDCTs), which involve widespread tissue fragility. Conditions such as Ehlers-Danlos Syndrome (hEDS) and Marfan Syndrome involve defects in connective tissue proteins like collagen and fibrillin. These genetic conditions result in chronically weak ligaments that make joints prone to repeated subluxations or dislocations. Furthermore, some joints, like the shoulder or hip, have naturally shallow sockets, a structural feature that reduces passive stability, making them more susceptible to displacement.
Chronic Causes: Acquired Damage and Functional Deficits
Instability can also be acquired, typically following a single traumatic event or repeated micro-traumas. A first-time dislocation often stretches or tears the joint capsule and ligaments, leading to chronic ligament laxity. This initial damage initiates a cycle where weakened structures make subsequent episodes of instability easier. Subsequent dislocations worsen soft tissue damage, increasing the likelihood of recurrence and potentially damaging cartilage or bone.
Functional deficits in the neuromuscular system also contribute to acquired instability. Neuromuscular control refers to the brain’s ability to coordinate muscle action to stabilize a joint. A specific issue is poor proprioception, the body’s unconscious awareness of the joint’s position and movement. After injury, nerve receptors within the damaged ligaments and joint capsule can be impaired, diminishing the ability to sense when the joint is moving into an unstable position. This poor feedback means dynamic muscles may not fire quickly enough to prevent the joint from “giving way,” compounding the risk of recurrence.
When to Seek Professional Guidance
Recurrent joint instability is a sign that the underlying support structures are compromised and should be evaluated by a healthcare provider. Immediate medical attention is necessary if the joint is visibly deformed, if you experience intense pain or inability to move it, or if there is numbness, tingling, or paleness in the limb. Never attempt to force a joint back into place yourself, as this can cause further damage to nerves and blood vessels.
A diagnosis typically begins with a physical examination to assess the joint’s range of motion and stability. Imaging tests, such as X-rays, MRI, or CT scans, are used to visualize damage to bones, ligaments, and cartilage. Specialists who treat chronic instability include orthopedic surgeons and physical therapists, who specialize in strengthening and improving joint function. A rheumatologist may be involved if a systemic condition, like a connective tissue disorder, is suspected.