|An ankle sprain is an injury to the ligaments around the ankle. An ankle strain is an injury to the tendons or muscles around the ankle. Ankle sprains and strains involve the stretching or tearing of tissue of the ligaments or the muscle-tendon unit, respectively.|
Sprains are classified according to the amount of tearing of the ligament. A first-degree sprain is one in which the ligament fibers are over-stretched but intact. A second-degree sprain is one in which some fibers are actually torn. A third-degree sprain is one in which the ligament is completely torn and nonfunctioning.
Strains can be categorized by the same manner as sprains, with first-degree indicating over-stretching, second-degree indicating partial tear, and third-degree indicating complete tear (rupture). Strains of the ankle are generally mild (first-degree). They are similar to sprains in the mechanism of injury, treatment, and prognosis.
An ankle sprain is typically caused by sudden, strong contraction, torsion, direct impact, or by a sudden, forceful straightening. Ankle sprains usually occur as a result of forcibly twisting the ankle or by landing from a jump on a foot that is turned in (inversion) or out (eversion). Basketball has the highest rate of ankle sprains of any sport. Sprains can also occur in football, soccer, volleyball, skiing, and martial arts.
Strains are either partial or complete tears of muscle-tendon units, usually the result of strong muscular contraction sustained in forceful stretching. They typically occur from the same activities and stresses as sprains, but are uncommon about the ankle joint. The tendons that traverse the ankle joint (peroneal tendons laterally; tibialis posterior and toe flexor tendons medially; tibialis anterior and toe extensor tendons anteriorly; the Achilles tendon posteriorly) are usually strained or ruptured at their point of insertion in the foot, rather than at the ankle level. The only exception to this is the Achilles tendon behind the ankle. This tendon can be strained in the leg, ankle, or foot.
The most common ankle injury is the lateral inversion ankle sprain, which accounts for 85% of all ankle sprains (Young). It occurs as the foot and ankle roll over sideways, causing damage to the ligament that connects the fibula to the talus and calcaneus. Another classification system for sprains (Leach classification) is based on which of the three ligaments in the area are torn (ruptured). A first-degree sprain is a rupture of the anterior talofibular ligament, a second-degree sprain is a rupture of both the anterior talofibular and calcaneofibular ligaments, and a third-degree sprain is rupture of both of these ligaments plus the posterior talofibular ligament. When the foot is turned out (eversion) during the injury, damage is to the inside (medial) of the ankle. The four ligaments in this area are called the deltoid ligaments. They are much stronger than the lateral ankle ligaments and rarely rupture. In fact, the bone insertion of these ligaments (medial malleolus) will usually fracture (avulsion fracture) before the ligament ruptures. A much less common sprain occurs to the ligament between the tibia and fibula (syndesmosis). This injury is called diastasis of the tibiofibular syndesmosis, or a "high" ankle sprain, and causes significant disability. This injury occurs when force is transmitted from the foot up the center of the ankle joint, such as landing on the foot from a height. Part of the function of ankle ligaments involves communicating with the nervous system via a stimulus feedback mechanism (proprioception) to help the individual maintain balance. When the ligaments are sprained, this important proprioceptive function may be distorted or lost, resulting in inversion injuries. It has been suggested that repeated “going over the ankle” (inversion injuries) may be due more to proprioceptor damage than to unstable ligaments (Cox).
Risk: Individuals who participate in athletic activities are more likely to experience ankle sprains and stains.
Incidence and Prevalence: Ankle sprains are one of the most common injuries presented for treatment. Daily incidence of ankle sprains in the US is estimated at 1 person in every 10,000. Most sprains result from athletic injuries, accounting for 15% of all athletic injuries (Foster).
Source: Medical Disability Advisor