Sprain


A sprain, also known as a torn ligament, is the stretching or tearing of ligaments within a joint, often caused by trauma abruptly forcing the joint beyond its functional range of motion. Ligaments are tough, inelastic fibers made of collagen that connect two or more bones to a joint and are important for joint stability and proprioception, which is the body's sense of limb position and movement. The majority of sprains are mild, causing minor swelling and bruising that can be resolved with conservative treatment. However, severe sprains involve complete tears, ruptures, or fractures, often leading to joint instability, severe pain, and decreased functional ability. These sprains require surgical fixation, prolonged immobilization, and physical therapy. Sprains can occur at any joint but most commonly occur in the ankle, knee, or wrist. An equivalent injury to a muscle or tendon is known as a strain.

Signs and symptoms

Knowing the signs and symptoms of a sprain can be helpful in differentiating the injury from a strain or fracture. Strains typically present with pain, cramping, muscle spasm, and muscle weakness, and fractures typically present with bone tenderness, especially when bearing weight.

Causes

Acute sprains typically occur when the joint is abruptly forced beyond its functional range of motion, often in the setting of trauma or sports injuries. Chronic sprains are caused by repetitive movements leading to overuse.

Mechanism

s are collagen fibers that connect bones together, providing passive stabilization to a joint. These fibers can be found in various organizational patterns depending on the function of the joint involved. Ligaments can be extra-capsular, capsular, or intra-articular. The location has important implications for healing as blood flow to intra-articular ligaments is diminished compared to extra-capsular or capsular ligaments.
Collagen fibers have about a 4% elastic zone where fibers stretch out with increased load on the joint. However, exceeding this elastic limit causes a rupture of fibers, leading to a sprain. It is important to recognize that ligaments adapt to training by increasing the cross-sectional area of fibers. When a ligament is immobilized, the ligament has been shown to rapidly weaken. Normal daily activity is important for maintaining about 80-90% of the mechanical properties of a ligament.

Risk factors

Diagnosis

Sprains can often by diagnosed clinically based on the patient's signs and symptoms, mechanism of injury, and physical examination. However, x-rays can be obtained to help identify fractures, especially in cases of tenderness or bone pain at the injured site. In some instances, particularly if the healing process is prolonged or a more serious injury is suspected, magnetic resonance imaging is performed to look at the surrounding soft tissue and ligaments.

Classification

  1. First degree sprain – There is minor stretching and structural damage to the ligament, leading to mild swelling and bruising. Patients typically present without joint instability or decreased range of motion of the joint.
  2. Second degree sprain – There is a partial tear of the affected ligament. Patients typically experience moderate swelling, tenderness, and some instability of the joint. There may be some difficulty bearing weight on the affected joint.
  3. Third degree sprain – There is a complete rupture or tear of the ligament, sometimes avulsing a piece of bone. Patients typically experience severe joint instability, pain, bruising, swelling, and inability to apply weight to the joint.

Joints involved

Although any joint can experience a sprain, some of the more common injuries include the following:
Treatment of sprains usually involves incorporating conservative measures to reduce the signs and symptoms of sprains, surgery to repair severe tears or ruptures, and rehabilitation to restore function to the injured joint. Although most sprains can be managed without surgery, severe injuries may require tendon grafting or ligament repair based on the individual's circumstances. The amount of rehabilitation and time needed for recovery will depend on the severity of the sprain.

Conservative measures

Depending on the mechanism of injury, joint involvement, and severity, most sprains can be treated using conservative measures following the acronym RICE within the first 24 hours of sustaining an injury. However, it is important to recognize that treatments should be individualized depending on the patient's particular injury and symptoms. Over-the-counter medications such as non-steroidal anti-inflammatory drugs can help relieve pain, and topical NSAIDs can be as effective as medications taken by mouth.
Other non-operative therapies including the continuous passive motion machine and cryocuff have been effective in reducing swelling and improving range of motion.

Functional rehabilitation

The components of an effective rehabilitation program for all sprain injuries include increasing the range of motion of the affected joint and progressive muscle strengthening exercises. After implementing conservative measures to reduce swelling and pain, mobilizing the limb within 48–72 hours following injury has been shown to promote healing by stimulating growth factors in musculoskeletal tissues linked to cellular division and matrix remodeling.
Prolonged immobilization can delay the healing of a sprain, as it usually leads to muscle atrophy and weakness. Although prolonged immobilization can have a negative effect on recovery, a study in 1996 suggest that the use of bracing can improve healing by alleviating pain and stabilizing the injury to prevent further damage to the ligament or re-injury. When using a brace, it is necessary to ensure adequate blood flow to the extremity. Ultimately, the goal of functional rehabilitation is to return the patient to full daily activities while minimizing the risk of re-injury.