Notching of the anterior femoral cortex during total knee arthroplasty (TKA) has been attributed to cause supracondylar fractures of the femur. Anatomic variations in the femur bone in different races make notching inevitable when standard designs of prostheses are used. The objective of this study is to determine the prevalence of notching when a PFC Sigma knee was used in an Indian population sample using the anterior referencing system and to assess the frequency of femoral shaft fractures in these cases.
This is a single-center, prospective study. All patients undergoing TKA were recruited and followed up for a minimum of 2 years. All patients had a PFC Sigma knee (DePuy Synthes), and the anterior referencing system was used for implantation. The Knee Society Score was used for outcome scoring and the Gujarathi's schema for the grading of notching. Radiological outcomes were evaluated by an independent observer. Linear regression analysis assessed the effect of notching on range of motion and final score.
Of the 200 cases, 21% had varying degrees of notching. Grade I was seen in 13%, grade II in 6.5%, grade III in 1%, and grade IV in 0.5% in this series. There was no supracondylar fracture in 2 years. Notching had no bearing on the range of movement or outcome scores.
Although notching is best avoided, this study has shown no correlation between notching and supracondylar fracture of the femur following TKA. It does not appear to have any bearing on the range of movement or final outcome scores.