Is There an Inherent Risk to Damage the Popliteus Tendon by Femoral Component With Inbuilt External Rotation? A Pilot Study in Indian Knees

Introduction Femoral components with inbuilt rotation require thicker flexion resection of the lateral femoral condyle and could have a potential risk of damaging the popliteus tendon, especially in the smaller Asian knees. Materials and Methods We prospectively evaluated 10 patients with bilateral varus osteoarthritis knee to size the cuts and their location in relation to the popliteus tendon. Two different types of implant were used on either side; one side requires resection in 3° external rotation (group A) and the other side requires a femoral component with inbuilt external rotation (group B). We observed the incidence of injury to the popliteus tendon and distance between flexion cut to its attachment over the lateral femoral condyle between both groups. Results We had popliteus tendon injury in 3 knees all from group B. Risk of damaging the popliteus tendon was found higher in group B, as the distance between flexion cut to popliteus tendon attachment was significantly low. Conclusion Femoral component with inbuilt external rotation has more risk of injuring the popliteus tendon because flexion cut takes out more bone from the lateral femoral condyle.