Determination of the Inter- and Intra-rater Reliability of Fusion Assessment in First Tarsometatarsal Joint Arthrodesis Using CT Scan: An Observational Study.

Background: First tarsometatarsal joint arthrodesis is a common procedure performed by podiatrists and orthopedic surgeons. There remains debate on how useful CT scans are in assessing fusion status in the post-operative patient. The purpose of our study was to determine the reliability among both orthopedic surgeons and radiologists in reviewing both postoperative radiographs and CT in order to determine if fusion had occurred in patients undergoing 1st tarsometatarsal arthrodesis. A secondary purpose of this study was to determine if CT offered improved inter- and intra-rater reliability when compared to plain radiographs.

Methods: Patients who underwent 1st tarsometatarsal arthrodesis were retrospectively reviewed and those who underwent CT post-operatively for persistent pain were identified. Orthopedic surgeons and radiologists then analyzed the radiographs and CT of these patients for union with a threshold for union being set at 50% of the joint being fused. Imaging was then re-evaluated by the same provider 6 months later.

Results: 24 patients were identified meeting inclusion criteria. Inter-rater reliability and intra-rater reliability for assessment of 1st tarsometatarsal arthrodesis were better with CT compared to radiographs; however, this association was not deemed reliable. Both imaging modalities were not able to assess union status confidently and reliably across reviewers, although CT scan had better intra-rater reliability.

Conclusions: While CT is frequently used to assess fusion in patients who have underwent 1st tarsometatarsal arthrodesis, it was not found to be better than radiographs. Practitioners should reconsider the use CT as the gold standard when assessing fusion in this population.