When a joint feels like it is “going out,” it points to an underlying issue with joint stability. This article will explore the mechanisms behind joint instability and the various factors that can contribute to this phenomenon, from common injuries to broader medical conditions.
Understanding Joint Instability
When a joint “goes out,” it means a temporary or complete displacement of the bones forming that joint. A subluxation is a partial displacement where the joint surfaces are misaligned, causing discomfort and a feeling of instability. In contrast, a dislocation involves a complete separation of the bones. Both events can cause sudden pain, swelling, and limited movement.
Joints are complex structures designed for movement while maintaining stability. Bones provide the structural framework. Covering the ends of these bones is articular cartilage, a smooth, flexible tissue that reduces friction and absorbs shock. Surrounding the joint, ligaments are tough, fibrous bands of connective tissue that connect bones to other bones, preventing excessive movement and maintaining proper alignment. Muscles and their tendons actively contribute to stability by dynamically adjusting to movements.
Common Causes of Instability
One of the most frequent direct reasons for joint instability is damage or laxity in the ligaments. Ligaments are designed to limit the range of motion and control joint movement. When these fibrous bands are stretched, torn, or naturally loose, their ability to hold bones together is compromised, which can lead to excessive movement or displacement. This can occur from acute injuries, such as a sudden twist or fall, or from repetitive strain over time.
Muscle weakness or imbalances around a joint also contribute to instability. Muscles provide dynamic support, and when they are weak or not properly coordinated, the joint loses active protection. For example, in the shoulder, the rotator cuff muscles are responsible for keeping the humerus head within the shallow glenoid cavity; a loss of tone in these muscles can lead to dislocation. Unbalanced training can predispose the knee to injury and chronic pain due to muscle imbalance.
A history of previous injury can significantly predispose a joint to future instability. Once ligaments or other joint structures have been damaged, they may not heal with their original strength or elasticity, leading to chronic laxity. Recurrent subluxations or dislocations can occur, sometimes necessitating surgical intervention to tighten or replace injured structures.
Repetitive stress from certain activities or movements can gradually weaken joint structures, increasing the likelihood of instability. Activities that involve repeated overhead arm motion, like throwing or swimming, can particularly affect joints such as the shoulder. This continuous strain can cause ligaments to stretch or connective tissues to lose integrity, making the joint more susceptible to “going out.”
Underlying Medical Conditions
Certain broader medical conditions can contribute to chronic joint instability. Generalized Hypermobility Spectrum Disorder (G-HSD) and Ehlers-Danlos Syndromes (EDS) are genetic conditions that affect connective tissue. Individuals with these conditions often have ligaments and other soft tissues that are naturally more elastic and less rigid than typical, resulting in overly flexible and frequently unstable joints. This increased laxity means their joints can easily move beyond their normal range, leading to recurrent subluxations or dislocations, even with minimal force.
Osteoarthritis, a condition characterized by the gradual degeneration of joint tissues, can also lead to instability in advanced stages. As the protective cartilage wears down, the smooth gliding surfaces of the bones become rough, and the joint space narrows. Severe degeneration can compromise the overall structural integrity of the joint, leading to abnormal mechanics and a feeling of looseness or instability.
Neurological conditions can impact joint stability by affecting muscle control or sensation. Conditions such as stroke, nerve damage, or other disorders that impair the nervous system’s ability to send proper signals to muscles can result in muscle weakness, spasticity, or impaired proprioception (the body’s sense of joint position). When muscles cannot adequately support the joint or when the brain receives inaccurate information about joint position, the joint becomes more vulnerable to instability and displacement. This can manifest as a loss of tone, making joints like the shoulder prone to dislocation.
Recognizing When to Seek Professional Advice
It is prudent to consult a healthcare professional if you experience persistent pain or swelling in a joint, as these symptoms can indicate ongoing damage or inflammation. An inability to move the affected joint normally, or a noticeable deformity of the joint, warrants immediate medical attention, as these are common signs of a dislocation or other severe injury.
Sensations such as numbness or tingling below the joint are concerning and suggest potential nerve involvement or compromised blood flow, requiring prompt evaluation. Recurrent episodes of a joint “going out,” whether partial or complete displacements, are clear indicators that the joint’s stability is compromised and needs professional assessment. Ignoring these repeated events can lead to further damage and chronic issues. If joint instability begins to impact your daily activities or significantly diminishes your quality of life, seeking professional advice can help identify the underlying cause and guide appropriate management.