What is Iselin's Disease?

Iselin’s disease is a rare cause of pain on the outside of the foot in children and adolescents. Its is an osteochondrosis or traction apophysitis at the base of the fifth metatarsal bone. The peroneus brevis tendon attaches to the area and puts it under a lot of stress. The condition is named after the German doctor Dr. Hans Isalin, who first described it in 1912. This apophysis at the base of the fifth metatarsal is a bone growth area that occurs generally appears at around 10-12 years of age, so Iselin's disease is usually more common after that age and is almost always associated with increased levels of sports activity. The higher loads associated with sports exert a lot of force on this growth area, which increases the risk of overuse. Usually there is no history of a single traumatic event that could have caused it.

The typical symptoms of Iselin’s disease are pain on the outside of the foot, especially near the base of the fifth metatarsal bone which is about the middle of the outside or lateral border of the foot. There may be swelling and tenderness in the affected area as well. The pain is worse with weight-bearing activity or walking and can cause limping. The pain will be even worse on sports activity, and it can be quite distressing for the child. X-rays of the area will usually show a fragmentation and irregularity of the bone with some cystic changes in the bone around the apophysis. The apophysis can also be enlarged on the x-ray. Iselin's disease should not be confused with a number of other conditions that can cause pain on the outside of the foot. This differential includes a Jones fracture (which is a fracture of the base of the fifth metatarsal); a stress fracture of the fifth metatarsal; a condition called cuboid syndrome; and a painful os vesalianum which is an extra bone at the base of the fifth metatarsal.

The treatment of Iselin’s disease usually begins with limiting activity of the child to a level that is not painful and they can tolerate. If the pain is severe enough, ice and pain medication may be needed after the sports activity. A complete rest from sport may be necessary if that initial activity restriction does not help reduce the pain. Resting the area can help with braces and orthotics, as well as good supportive shoes. Immobilization with a walking brace or CAM boot may also be necessary for up to a month if needed. As the symptoms subside, the amount of support given to the foot can be slowly reduced and the sports activity levels can be very slowly and gradually increased. If this is not done carefully, the symptoms may return and you have to start all over again. Regardless of how this treatment works, Iselin's disease will always resolve spontaneously on its own as the apophysis, or growth region, fuses with the main body of the fifth metatarsal bone as the skeleton matures as part of natural development.