Making Waves: A Case of Ankle Pain in a 14 Year-old Competitive Figure Skater Treated with Shockwave Therapy

Case Diagnosis: 14 year-old competitive figure skater presenting with eight months of left ankle pain.

Case Description or Program Description: She underwent os trigonum resection 3 months prior for similar symptoms but has persistent pain with pointing her foot and landing from jumps while skating. The pain is sharp and localized to the posterior ankle. It improves with rest and consistent PT. She denies pain with walking. Her surgeon offered cortisone injections, but her mom declines because she underwent ultrasound-guided injection prior to her surgery without relief. Examination of the left foot and ankle demonstrates no deformities, asymmetries, or tenderness to palpation. Full ankle ROM without ligamentous laxity. Full strength with plantarflexion, dorsiflexion, eversion and inversion, but full plantarflexion reproduces pain.

Setting: Outpatient clinic

Assessment/Results: MRI of the left foot/ankle done 2 months after ankle surgery was consistent with excision of os trigonum and demonstrated inflammatory synovitis distending the posterolateral joint recess with incomplete remodeling of the joint capsule, as well as immature scarring and fibrosis effacing the regional sural nerve branches.

The patient was diagnosed with posterior impingement syndrome due to postoperative scarring and fibrosis following os trigonum resection. She underwent four ESWT sessions (0.15-0.20mJ/mm2, 3000 pulses, 5-6 Hz each) to the posterior left ankle with good relief, allowing successful return to competitive figure skating. MRI confirmed resolution of sural nerve effacement and improved capsulitis.

Discussion (relevance): Os trigonum syndrome is a cause of posterior ankle pain and reduced plantarflexion, often resulting from overuse or trauma in ballet dancers and runners. Treatment aims to reduce inflammation with NSAIDs and steroid injections. In cases of refractory pain, surgical resection of the os trigonum is indicated. In recent years, ESWT has emerged as an effective treatment in cases of chronic foot/ankle pain, most commonly plantar fasciitis and achilles tendinopathy.

Conclusions: This case highlights ESWT as an effective yet non-invasive therapeutic intervention not only as an alternative to surgery, but furthermore as a safe and innovative treatment option for cases of refractory postoperative ankle pain in the setting of os trigonum syndrome.