Agreement between Sanders classification of intraarticular calcaneal fractures and assessment during the surgery

Sanders classification, based on the number of displaced fractured fragments of posterior facet, can predict the prognosis of calcaneal intraarticular fractures. The aim of the study was assessing not only intraobserver reproducibility and interobserver reliability of Sanders classification but also the agreement between preoperative reported types based on computed tomography (CT) scan and direct observation during the surgery.

In this cross-sectional study, preoperative CT scans of 100 patients with intra-articular calcaneal fracture operated by a single surgeon were studied by two orthopedic and trauma surgeons (A & B), twice with an interval of three weeks. Their result were compared with each other and with the number of displaced fractured fragments recorded in the operation notes. Quadratic weighted kappa test was used to check the agreement between two observers and between the observers and the surgeon.

Intraobserver reproducibility for Sanders classification of intraarticular calcaneal fractures was found to be good to excellent (A1-A2: 0.91 and B1-B2: 0.75). There was a moderate agreement between the two observers (A1-B1: 0.56, A1-B2:0.58, A2-B1:0.48, and A2-B2:0.51). The agreement between reported types of Sanders classification and the number of displaced fractured fragments seen during the surgery was fair (A1-surgeon: 0.27, A2-surgeon: 0.29, B1-surgeon: 0.38, and B2-surgeon: 0.50).

Agreement between Sanders classification and what is real during surgery is fair. Hence, Sanders classification as determined in the widest cut of coronal CT scan extended posteriorly should be cautiously interpreted for surgery.