· anterior displacement of peroneal tendons out of peroneal groove
· most common in young adults
· acute injury often missed
· occurs following sporting activities
· snow skiing
· football
· gymnastics
· due to violent contraction of peroneal muscles
· leads to tendons overcoming their fibro-osseous sheath
· sheath may be
· torn
· stripped off lateral malleolus
· predisposed by anatomical variants
· laxity of peroneal retinaculum
· convex or flat posterior surface of distal fibula
Acute
· sudden pain behind lateral malleolus
· snap may be heard
· unable to continue with activities
Chronic
· ankle giving way
· painful snapping of lateral ankle with activity
· tenderness and swelling behind lateral malleolus
· pain or dislocation reproduced by active eversion
· usually normal
· may be avulsed fragment of cortical bone lateral to lateral malleolus
· defines anatomy and relationships of tendons
· may detect anatomical variants
· detects tendinous and ligamentous injuries
· may detect tendon attrition
· opinion divided re acute injuries
· some recommend nonoperative treatment
· some advocate surgical repair
· most treat chronic injuries surgically
· for acute injuries
· cast in plantarflexion for 6 wks
· good results reported
Acute
Retinaculum stripped
· reattachment to posterior malleolus
· to fibrocartilagenous ridge or to bone through drillholes
Retinaculum torn
· primary repair
With bony avulsion
· fragment reattached
· with sutures, wires or screws
Chronic
Soft tissue reconstruction
· direct repair performed if possible
· if not, reconstruction of new retinaculum
· can use
· osteoperiosteal flap
· slip of tendo Achilles
Groove deepening
· by sliding bone block OR
· by decancellation and cortical recession
Rerouting
· substitution of calcaneofibular ligament for peroneal retinaculum
· tendons transposed into inframalleolar tunnel