Foot Pain in a Runner

Abstract

HISTORY: 16 yo high school cross country runner presents with left foot pain. Patient had been diagnosed with a left fifth metatarsal fracture and cuboid stress fracture in the recent past and was seen and treated by an outside physician. Upon visiting our clinic, a bone density scan revealed significantly low bone mineral density for his age. Repeat MRI showed patchy bone marrow changes within the midfoot, most prominently at the cuboid bone with increased signal within the fifth metatarsal. He was referred to an endocrinologist. Further lab work revealed elevated urinary markers secondary to trauma and osteoprosis, consistent with idopathic juvenile osteoporosis. He was seen by a pediatric orthopedic surgeon, that also considered the diagnosis of bone marrow edema syndrome. PHYSICAL EXAMINATION: MSKL: No bony tenderness over the lateral foot including the cuboid or fifth metatarsal. Decreased inversion of the left ankle. Calcaneal angle at rest on the left is 0, right is 7 degress. Calcaneal angles with inversion on the left is 16 degress, on the right is 13 degress. The calcaneal angle with eversion is 10 degress on the left and 10 degress on the right. Strength testing reveals 5/5 strength of ankle dorsiflexion, plantar flexion, inversion, eversion and knee extensors. DIFFERENTIAL DIAGNOSIS:idiopathic juvenile osteoporosis, bone marrow edema syndrome TEST AND RESULTS: DEXA scan 8/09 Femoral neck: Z score -2.5, T score: -2.7 Total hip: Z score -1.7,T score - 2.5 AP spine (L1-L4): Z score -1.0, T score -2.3 BMD is significantly below the age and sex matched values Labs: 9/25/09 Ca 9.6, Phos 5.0, AP 212, TSH 0.74, Pyridinium 137.5, DPD/PDY 0.28, testosterone 496, PTH 44, 25OH Vit D 52, CBC 5.8, HGB 13.4 HCT 40, plt 219 9/15/09 xray left foot Generalized, moderate osteopenia, cortical thicking of the 5th metatarsal, consistent with healing or healed stress reaction, irregularity of lateral cortical margin of the cuboid, possible nondisplaced fracture of the cortex FINAL WORKING DIAGNOSIS: Idiopathic juvenile osteoporosis TREATMENT AND OUTCOMES: The patient was placed in a walking boot. He was to continue calcium/vitamin D supplementation in his foods, initiate weight bearing exercises, stationary bicycling, rowing, and to avoid running. Idiopathic juvenile osteoporosis is expected to spontaneously resolve in two years.