Presentation
Military trainee with foot pain. Concern for stress fracture
Patient Data
Single phase lower body bone scan. Images obtained 3 hours following the administration of 20 mCi of Tc99m MDP IV.
Anterior and posterior planar views of the lower body demonstrate mild asymmetric increased radiotracer uptake in the right foot.
Lateral spot views of the feet show increased radiotracer uptake in the right hind/mid foot.
Plantar spot views of the feet show a similar finding.
There is no uptake in the metatarsals to suggest stress fracture. Likewise, no evidence of calcaneal stress fracture. The uptake in the right foot is unlikely to represent a bone stress injury and hence radiographs were recommended for correlatio
Right foot radiographs show no features of a bone stress injury. There is significant joint space narrowing and subchondral sclerosis between the calcaneus and navicular bones. This is consistent with a calcaneonavicular coalition.
Lateral view confirms such and demonstrates the anteater sign.
Case Discussion
Calcaneonavicular coalition is one of the two most common subtypes of the tarsal coalition, the other being talocalcaneal coalition.
Given the sclerosis, increased radiotracer uptake at sites of coalition can be encountered on bone scan as in this patient. When the abnormal radiotracer uptake is in the subtalar region, coalition can be suggested as a possibility. If available, SPECT-CT can be used for definitive assessment.
Unable to process the form. Check for errors and try again.