Radiographic Union Scoring Scale for Determining Consolidation Rates in the Calcaneus

The reliable evaluation of osseous consolidation after hindfoot osteotomy can be difficult. Concomitant hindfoot osteotomies often dictate the advancement of weightbearing, and radiographs are the mainstay imaging tool owing to cost, efficiency, and radiation exposure. Understanding the radiographic parameters that can be used to reliably determine osseous healing is paramount. However, currently, no reliable or validated method is available to determine osseous healing of hindfoot osteotomies in irregular bones of the foot. The purpose of the present study was to develop a radiographic healing scoring system that would enhance the diagnostic healing assessment after elective calcaneal osteotomy. We adapted existing orthopedic scales validated for healing in the leg for application in the irregular bones of the foot. A total of 168 cases were evaluated by 6 blinded assessors to test the interrater reliability of subjective healing assessment compared with the proposed scoring system. The radiographs were classified by postoperative period: ≤4 weeks, 5 to 12 weeks, and >12 weeks. The proposed scale had high interrater reliability but was burdensome. Using a priori item reduction protocols, a limited 6-item scale further improved internal consistency and reduced the burden. The result was excellent interrater reliability (α = 0.98, standard deviation 0.02, 95% confidence interval 0.91 to 0.96) among all assessors when using the scoring scale compared with unacceptable reliability (α = 0.438) for subjective osteotomy healing. The reliability of our system appeared superior to that of subjective assessment of osseous healing alone, even in the absence of clinical correlates after osteotomy of the calcaneus.