Ankle inversion injury not responding as expected – normal plain film x-ray
Review history, physical examination and rehabilitation Stable ankle Yes
Lateral ligament complex injury only
Other injury suspected
Rehabilitation review ● Strength ● ROM ● Proprioception ● Sport specific drills
Triple phase bone scan
Investigate – consider cost & availability
● Stress films
● Surgical opinion
Rehabilitation review ● Strength ● ROM ● Proprioception ● Sport specific drills ● Taping/bracing
No Recurrent episodes
Specific treatment for other diagnosis Diagram 1: Suggested management protocol for an unresponsive ankle
fond and also fractures of the posterior process of the talus. If an os trigonum is present (Fig.4) its fibrous attachment to the talus may be disrupted and this will invariably require excision.
6. SINUS TARSI SYNDROME Probably one of the most frequently missed soft-tissue lesions following ankle inversion injury is the sinus tarsi syn- drome.
The mechanics of injury to the
subtalar joint have been discussed earlier and independent studies by subtalar arthrography and MRI have confirmed abnormalities of the sinus tarsi in more than 40% of Grade II - III ankle inversion injuries.
Anatomy: The tarsal canal is a cone- shaped cavity which separates the anteri- or and posterior talo-calcaneal joints.
is widest at its lateral end and the depres- sion of the opening can be palpated just
antero-inferiorly to the tip of the lateral malleolus.
The canal runs at an angle of
45o to the lateral aspect of the calcaneum and is about 20mm long but narrows sig- nificantly as it passes medially.
tains the cervical ligament, which con- nects the neck of the talus and calca- neum, the inferior extensor retinaculum and the interosseus talo-calcaneal liga- ment at its medial end. A branch of the deep peroneal nerve and the posterior tib- ial artery (supplying the talus) penetrate a large fatty plug in the outer aspect as they descend postero-medially down the canal.
The sinus tarsi syndrome was
described by O’Connor in 1958 and was initially treated surgically by debridement of the contents of the canal.
Presentation: Characteristic features are antero-lateral ankle pain usually following inversion injury, a feeling of rearfoot insta- bility manifested by difficulty walking on
uneven terrain, tenderness over the sinus tarsi opening and relief of symptoms by injection of local anaesthetic into the tarsal canal.
EMG studies in gait have
shown a significant reduction in peroneal muscular activity in association with this syndrome that is restored following injec- tion of local anaesthetic into the canal. This may explain to some degree why these subjects have difficulty rehabilitating.
MRI examination can show a variety of appearances but loss of the normal mor- phology of the canal contents is charac- teristic and may be associated with: (a) diffuse infiltration with low T1- and T2-weighted signal intensity consistent with fibrosis (b) diffuse infiltration with low T1- weighted signal intensity and increased T2-weighted signal intensity consistent with chronic synovitis and nonspecific inflammatory changes