ABSTRACT
PURPOSE: To validate the use of the clock face reference as a reliable means of communicating femoral intercondylar notch position. METHODS: A single red mark was made on ten identical left Sawbones femurs in the intercondylar notch at variable locations. Ten surgeons, who routinely perform ACL reconstructions, were presented the femurs in random order and asked to state the position of the mark to the nearest 30-min interval. Responses were recorded and then repeated 3 weeks later. The same 10 surgeons were presented with 30 actual arthroscopic photographs of the intercondylar notch, performed at 90° of knee flexion, with a probe pointing at various locations (10 knees; 3 photographs/knee) along the lateral aspect of the notch. The results were then analyzed with an ICC, Cronbach's alpha test, and descriptive statistics. RESULTS: For the Sawbones, the ICC was 0.996 while individual physician's Cronbach's alpha test ranged from 0.954 to 0.999, indicating a very high interobserver and intraobserver reliability. The mean range of responses among the 10 surgeons was 1.6 h, SD 0.6. For the photographs, the ICC was also high at 0.997. There was a mean range of 1.1 h, SD 0.4, among surgeons. CONCLUSIONS: The clock face method is commonly utilized for both placement of the femoral tunnel during ACL reconstruction as well as describing the location of the ACL femoral tunnel between communicating surgeons. Despite a high statistical interobserver correlation, there is significant range among different surgeons' responses. The present study questions the reliability of the clock face method for use between surgeons as a stand alone tool. Other methods also utilizing anatomic landmarks may be more accurate for describing intercondylar notch anatomy. LEVEL OF EVIDENCE: III.
