Foot Pain in an Adolescent Runner

Abstract

HISTORY: A 16 year old cross country runner averaging 42 miles per week began to experience pain in the dorsal medial aspect of his left foot one day while running. The patient informed his athletic trainer who recommended rest and wearing a walking boot on the left foot for 1 week. After 1 week, the pain had completely resolved, and the patient was allowed to resume running. The patient remained pain free for 2 weeks, however, his dorsal medial left foot pain resurfaced. He resumed rest and wearing the walking boot, and sought further evaluation at the Sports Medicine clinic. PHYSICAL EXAM: Examination in clinic revealed no tenderness to palpation of the feet bilaterally. No deformity, erythema, edema, ecchymoses was noted along the lower extremities or in the feet bilaterally. Pt had 5/5 strength with dorsiflexion, plantarflexion, inversion, eversion bilaterally. Pes Planus noted bilaterally. DIFFERENTIAL DIAGNOSIS: -Navicular Stress Fracture -Metatarsal Stress Fracture -Posterior Tibial Enthesopathy -Shoe Midfoot Entrapment TEST AND RESULTS: -Xray Left Foot: Negative for fracture. -MRI Left Foot: Nondisplaced incomplete stress fracture of the base of the 1st metatarsal. Marked edema and T1 hypodensity of all 5 distal phalanges, and the second and third middle phalanges. -DEXA Scan: Lowest measured Z-Score is AP Spine L1-L4 with Z-Score -;1.8. -Vitamin D Level: 22.8. FINAL/WORKING DIAGNOSIS: 1st Metatarsal Stress Fracture likely secondary to previously undiagnosed Idiopathic Juvenile Osteopenia TREATMENT AND OUTCOMES: 1. Ambulation with the walking boot for 6 weeks. Bicycling for 30 min per day while wearing the boot allowed, but no running or jumping activities. 2. Referral to Family Physician and Endocrinologist, and Vitamin D supplementation started. Follow-up Vitamin D level in 3 months. 3. Repeat XRays of the left foot obtained after 6 weeks in the walking boot. XRays negative for fracture. 4. Walking boot discontinued 6 weeks post-injury. Physical therapy started with a focus on foot and ankle strengthening exercises. 5. Repeat MRI Left Foot 8 weeks post-injury showing healing 1st metatarsal stress fracture and stable abnormal marrow signal in the distal phalanges. 6. Walk to run program started 8 weeks post-injury with eventual full return to sport when pain-free running achieved.