Evaluation of the painful foot is simplified because all aspects
of the foot that may be designated as the site of pain by the patient
are visible, palpable, and reproducible to the examiner. The tissue sites
of pain in the foot are the joints, ligaments, tendons, or peripheral
nerves. The mechanisms of pain and disability are elucidated by
the patient in the history.
The ankle essentially consists of the talotibial joint. The talus
fits within the mortise formed by the malleoli of the tibia and
the fibula, allowing primarily flexion and extension with limited
lateral flexion on rotation. The talus allows no lateral or rotational
movement within the mortise when dorsiflexed but allows some lateral
motion when fully plantar flexed. It is in the plantar flexed position
that the ankle sustains injury to its ligaments when there is excessive
lateral rotatory movement upon the fixed foot.
The ankle joint is made stable by its collateral ligaments. The
ligaments on the medial side are the deltoid ligaments: anterior
talotibial, tibionavicular, calcaneotibial, and posterior talotibial.
Those on the lateral side are the anterior talofibular, calcaneofibular,
talocalcaneal, and posterior talofibular. All ligaments are named
according to the bones they connect and sustain injury when these bones
are excessively separated from the sustained injury. The anterior
talofibular ligament is the weakest and most frequently injured
ligament (Figs. 33-1 and 33-2).
Lateral collateral ligaments.
Medial (deltoid) collateral ligaments.
A strain is a force, and a sprain is tissue damage from excessive
strain. This damage may involve tearing of individual collagen fibers
composing the ligament. The number and degree of sprain depends
on the number and extent of the collagen fibers injured.
The history reveals the mechanism by which the ligamentous injury
occurred. Local pain, tenderness, and swelling are common findings.
Examination reveals the extent of swelling and tenderness. Mere
edema implies minor sprain, whereas ecchymosis implies tearing,
causing microhemorrhage and more severe injury.
The examination will determine which ligament has been damaged
and to what degree. The degree of inversion of the foot compared
with the opposite side, using the same technique and moving the
feet identically, reveals the degree of ligamentous injury. A complete
tear allows excessive motion. A positive drawer sign implicates
the posterior or anterior talofibular ligaments.
Diagnosis is basically made by examination, but stress films
may reveal talar tilt within the mortise. X-ray studies may also
reveal an avulsion fracture when the lateral collateral ligaments
have been excessively stressed.
Treatment depends on the severity of the injury. Mild sprain
(grade I) is an ...