This patient's history, examination, and images are consistent with chronic anterior tibialis rupture. This injury most often occurs in middle-aged patients following an eccentric loading of a degenerated tibialis anterior tendon against a plantar flexed foot. The classic triad for anterior tibialis ruptures include: (1) a pseudotumor at the anterior part of the ankle that corresponded with the ruptured tendon end, (2) loss of the normal contour of the tendon, and (3) weak dorsiflexion of the ankle accompanied by hyperextension of all of the toes can help to make the diagnosis.
Sammarco et al present a Level 4 review of 19 patients with traumatic or atraumatic ruptures that were surgically treated in an early (<6 weeks) or late (>7 weeks) manner. Patients who were managed surgically both early and late had improvements in dorsiflexion strength and gait pattern and had a significant improvement in the AOFAS hindfoot score as compared with the preoperative value. The authors advocate repair or reconstruction of the tendon to restore dorsiflexion and inversion of the ankle in order to approximate a normal gait pattern and theoretically to avoid the late development of foot deformity
Ouzounian et al present a Level 4 review of 12 patients with chronic anterior tibialis ruptures. Two types of ruptures were identified on the basis of clinical presentation: (1) atraumatic ruptures, which occurred in low-demand older patients who presented late with minimal dysfunction and (2) traumatic ruptures, which occurred in higher-demand younger patients who presented earlier with more disability. The authors concluded (1) that patients with traumatic ruptures, regardless of the time of presentation, demonstrated better function after operative intervention and (2) that patients with atraumatic ruptures who present early should be managed surgically, whereas those with delayed presentation could be managed with bracing.
Illustration A demonstrates a loss of normal contour of the anterior tibialis tendon of the right ankle associated with a rupture of the anterior tibialis tendon.
Sammarco VJ, Sammarco GJ, Henning C, Chaim S. Surgical repair of acute and chronic tibialis anterior tendon ruptures. J Bone Joint Surg Am. 2009 Feb;91(2):325-32.
PMID:19181976 (Link to Abstract)
Ouzounian TJ, Anderson R. Anterior tibial tendon rupture. Foot Ankle Int. 1995 Jul;16(7):406-10.
PMID:7550953 (Link to Abstract)