Metatarsalphalangeal joint sprain

A metatarsalphalangeal joint sprain is an injury to the joint and connective tissue between the foot and one of the toes. When the big toe is involved, it is known as "turf toe".

Causes
Turf toe is named from the injury being associated with playing sports on rigid surfaces such as artificial turf and is a fairly common injury among professional American football players. This can also happen when the nail bed is forced into the cuticle and swelling with isolated pain may occur.

Often, the injury occurs when someone or something falls on the back of the calf while that leg's knee and tips of the toes are touching the ground. The toe is hyperextended and thus the joint is injured. Additionally, athletic shoes that tend to have very flexible soles combined with cleats that "grab" the turf will cause overextension of the big toe. It should be noted that this can occur on the lesser toes as well. (See Deion Sanders)

Treatment and prognosis
The injury can be debilitating for athletes who need to accelerate, 'cut' quickly, or jump. Use of the toes is not possible during the healing process. Since the toes are necessary for proper push-off when accelerating, those sorts of athletic activities can be almost completely curtailed. A healing period of one or more months is often required.

Because of the anatomy of the distal foot and the unique use of the foot, it is often impossible to properly tape or brace the joint. Although difficult, it is not impossible to tape the toe to limit dorsiflexion (upward bend of toe). Additionally, wearing a shoe with a rigid sole and cushioned innersole will help. Anti-inflammatory medication as well as physical therapy is recommended.

Turf toe can often progress into a chronic problem, in which the joint(s) never really heals or heals too slowly to return to usual physical activities.

Turf toe can become more serious if left untreated.

Notable cases
Deion Sanders was plagued with this injury throughout his career, with serious reductions in playing time near the end of his football career.

A bad case of Turf Toe ended former Pittsburgh Steeler Jack Lambert's career in 1984.