Objectives Lower extremity stress fractures and stress reactions result in moderate to severe functional limitations that often preclude participation in sports and recreational activities, that involve vigorous repetitive lower limb activities and training. However these athletes may have other systemic or locoregional pathologies that may symptomatically mimic tibial stress injury. Our aim in this study was to evaluate stress injury type with bone scan, relation of exercise duration per week and contribution of SPECT/CT in recreational athletes with calf pain.

Methods One hundred and forty nine patients (25 bilateral symptoms) with age of 18–53 with tibial pain who had undergone a three phase dynamic Tc-99 m MDP bone scan between January 2014 and May 2016 were included to the study. Stress injury types were determined as simple stress injury, shin split or stress fracture up to their uptake features in three phase dynamic images and uptake intensity. In case of subtle, inappropriate uptake or other sites of uptake in whole body images SPECT/CT was performed. 149 patient of 174 legs were divided into four groups (Group 1 stres injury, group 2 stress fracture, group 3 shin splint and group 4 healthy legs as control). Duration of weekly exercise were statistically analysed.

Results There was no statistically significant difference between the groups in terms of age and symptoms durations (p > 0.05). There was a statically difference in exercise duration per week between the groups (p = 0.012) (Table 1). 10.5% of subjects who dealt with sports 5 hours or less was evaluated as “pathological” whereas 53% of 10 hours or more dealers were in the same category.

87/149 bone scan revealed one or more foci compatible with stress injury. Among 149 patients 41 had also undergone a SPECT/CT scan. 20/70 patients who have stress injury in bone scans had positive findings bilaterally. There was a statically difference in a SPECT/CT scan between groups (%38, 5, %50, 0, %13, 9, %18, 2, p = 0.002 respectively). SPECT/CT images revealed stress fractures of metatarsal region in nine patients and also demonstrated five other causes of Tc-99m MDP uptake which were a fibroxantoma, a giant cell bone tumour, a polyosthotic bone disease, a an osteoid osteoma and a unilateral sacroileitis.

Conclusions Dynamic -three phase bone scan is a conventional method in assesment of stress injuries. SPECT/CT imaging has a leading and distinctive role for also other musculoskeletal disorders and may offer a different opportunity for treatment and follow ups. Duration of exercise is also an important factor for discrimination of stress injury patients.

Reference

1. Shaffer SW, Uhl TL. Preventing and Treating Lower Extremity Stress Reactions and Fractures in Adults. J Athl Train 2006 Oct–Dec; 41(4):466–9.