Ankle Pain: Kickball, Basketball, And Running

HISTORY: A 16-year-old male presents to the gait lab with left ankle pain. He is active in basketball, kickball, and football. He experiences lateral foot pain, particularly during running and kicking, now persisting during regular ambulation. The patient is in physical therapy, stretches regularly, and has custom orthotics for arch support. These provide some relief but are insufficient to overcome ongoing sports-related difficulties. There is no numbness, tingling, or radiation. PHYSICAL EXAMINATION: Examination revealed bilateral plano valgus, tenderness anterior to the left lateral malleolus, reduced passive range of motion in plantarflexion, dorsiflexion, and inversion, notably worse on the left side than right with 0 degrees of inversion. Ankle active range of motion was grossly impaired bilaterally. Ankle strength rated 3/5 on the left, 4/5 on the right, and the Modified Ashworth score of the foot everters was 3/5 on the left and 2/5 on the right. Pain was reproduced with short distance walking. He was able to perform 10 toe raises on the left and 5 on the right. Reflexes were normal. DIFFERENTIAL DIAGNOSIS: 1. Ankle Sprain/Fracture 2. Dynamic Muscle Spasm 3. Peroneal Neuropathy TEST AND RESULTS: Instrumented Gait Analysis: -Walking velocity of 1.15 m/s, symmetric stance/swing phase time, and step length. -Severe bilateral pes planus worse on the left Left Limb Dynamic Polyelectromyography: -Peroneus longus: Phasic activity in stance phase. -Peroneus brevis and tertius: Activity in early stance, swing phase. Delayed onset of tertius compared to brevis. -Active eversion: Activation of peroneus brevis and tertius only -Passive inversion: Tonic stretch in peroneus tertius and brevis. -Active inversion: Co-contraction of peroneus brevis -Passive plantarflexion: tonic stretch in peroneus tertius and brevis only -Active plantarflexion: decrease in amplitude of the peroneus tertius consistent with reciprocal inhibition FINAL WORKING DIAGNOSIS: Focal dystonia of the left peroneus brevis and tertius TREATMENT AND OUTCOMES: 1. Stimulation-guided botulinum toxin chemodenervation 2. Continued physical therapy and stretching. 3. Continued orthotic use and surgical evaluation. 4. Full return to all sports six months post-injection. Pain-free, normal strength, and increased running speed.