Measuring the Femoral Head Size — An Additional Real-Time Intraoperative Monitoring Tool for the Accuracy of the Preoperative Process and Implant Selection

The purpose of this study was to examine the correlation between the implanted cup’s outer diameter and the actual femoral head diameter removed during surgery. Seventy-five patients with primary total hip arthroplasty were evaluated. The difference between the implanted cup diameter and the femoral head diameter was calculated for each patient. The mean ± SD actual femoral head diameter that was removed and measured during surgery was 48.5 ± 3.7 mm. The mean ± SD cementless implanted cup outer diameter was 51.8 ± 3.5 mm. A high correlation was found between the implanted cup diameter and the actual femoral head diameter (r = 0.923). A cut-off point of 4 mm of the measured femoral head diameter should be considered as an additional monitoring indicator.