Plantar fascia rupture is not a very common injury. It occurs due to a tear in the plantar fascia, and its main characteristic is acute pain in the arch of the foot.
Rupture is often associated with long-standing flat feet deformity or can occur from steroid injections. Another predisposing factor for plantar fascia rupture is plantar fasciitis.
Anatomy
The plantar fascia is formed by three bands- the medial, the central, and the lateral. The plantar aponeurosis is the central part of the plantar fascia. The plantar fascia is inserted into the medial tuberosity of the calcaneus and extends distally, becoming broader and thinner.
The plantar fascia acts as a bow string. It is the dynamic stabilizer of the longitudinal arch of the foot.
Rupture
The rupture of the plantar fascia may be misdiagnosed as plantar fasciitis. Often times, however, when the plantar fascia tears, the patient will describe a tearing pain that usually occurs during athletic activity. The patient may feel a “popping” or “snapping” suddenly. The rupture is commonly in the arch of the foot opposed to where the plantar fascia inserts into the heel (calcaneus).
The tear may be complete or incomplete. Complete tear of the plantar fascia occurs from sudden trauma or injury. A partial rupture is less common and occurs from overuse, as in running. MRI will identify the rupture and it can also identify if the rupture is partial or complete.
Walking will be very difficult with tenderness, swelling, and significant bruising on the sole of the foot. Some patients may even have a noticeable tightness of the calf muscle (equinus contracture) in association with rupture of the plantar fascia.
Imaging
Ultrasound has the same accuracy as MRI for imaging the plantar fascia. However, interpretation of the plantar fascia can be difficult. Dynamic maneuvers with dorsal flexion of the forefoot to stretch the plantar fascia may be needed while using an ultrasound to diagnose a rupture. Usually, the proximal part of the plantar aponeurosis is clearly visualized on ultrasound.
MRI is probably better in diagnosing plantar fascia rupture.
Treatment
The patient should be non-weight bearing for 2-3 weeks, and should be placed in a walking boot and use crutches. They should also complete physical therapy.
Surgical treatment is the last resort. However, it may be used in some athletes who continue to have pain despite a well conducted conservative treatment. Surgery is performed to release the fascia and to excise the scar.
Patients with rupture of the plantar fascia typically achieve a favorable outcome with return to full activity.
