Interobserver and intraobserver reliability of radiographic evidence of bone healing at osteotomy sites

Plain radiographs are commonly used to evaluate the degree of bone healing after an osteotomy and the application of an external fixator. The purpose of the study was to assess intraobserver and interobserver reliability in determining bone healing, defined as bridging callus across three of four cortices, of osteotomy sites on radiographs. Substantial intraobserver reliability and a high intraobserver percentage agreement were found. Interobserver reliability was moderate and interobserver percentage agreement was less than half for agreement between all involved orthopaedic surgeons. The lower reliability across surgeons suggests that the determination of the extent of the bone healing is subjective.