Radiographic signs of union of scaphoid fractures. An analysis of inter-observer agreement and reproducibility

Inter-observer agreement and reproducibility of opinion were assessed for the radiographic diagnosis of union of scaphoid fractures on films taken 12 weeks after injury. Weighted kappa statistics were used to compare the opinions of eight senior observers reviewing 20 sets of good quality radiographs on two occasions separated by two months. There was poor agreement on whether trabeculae crossed the fracture line, whether there was sclerosis at or near the fracture and on whether the proximal part of the scaphoid was avascular. As a consequence, agreement on union also was poor; it appears that radiographs taken 12 weeks after a scaphoid fracture do not provide reliable and reproducible evidence of healing.