Abstract
Introduction
The popliteus tendon is a component of the posterolateral corner of the knee, which controls the external rotation of the tibia. In our clinical practice, the femoral footprint of the popliteus tendon is occasionally excised as the bone is resected during total knee arthroplasty (TKA). Although the excision of the popliteus tendon femoral footprint could result in excessive external rotation of the tibia and may have adverse effects on the long-term outcomes of TKA, little attention has been paid to the popliteus tendon femoral footprint during TKA. The purpose of the present study is to assess the frequency of the excision and its associated risk factors.
Methods
One hundred eleven knees of 90 patients with varus knee osteoarthritis who underwent primary TKA were included in the present study. There were 13 males and 77 females, and their average age was 74 years. The NexGen knee replacement system (Zimmer, Warsaw, IN, USA) was used in all cases. The excision of the popliteus tendon femoral footprint was intraoperatively evaluated, and the patients were divided into three groups depending on the status of the femoral footprint, i.e., the preserved, partially excised, and completely excised groups. The thickness of the distal femoral osteotomy, femoral component size, and background data including height, body weight, gender, and age were compared among these groups. Analysis of variance followed by Student–Newman–Keuls test were used to compare the continuous values and ordinal scales. Gender was compared using Fisher's exact test and residual analysis. Statistical significance was set at p < 0.05.
Results
The popliteus tendon femoral footprint was preserved in 48 knees (43.2%), partially excised in 45 knees (40.5%), and completely excised in 18 knees (16.2%). The mean patient height was 154.6, 150.1, and 148.7 cm in the preserved, partially excised, and completely excised groups, respectively, and these differences were statistically significant (p < 0.01). Femoral component size was significantly smaller in the partially and completely excised groups compared with that in the preserved group (p < 0.05). The preserved group included more male patients (p < 0.01). There were no significant differences in body weight, age, and thickness of the distal femoral osteotomy among the groups.
Conclusion
The partial or complete excision of the popliteus tendon femoral footprint was observed in more than half of the evaluated knees. Shorter height, smaller femoral component size, and female sex were considered to be the possible risk factors for the excision of the popliteus tendon femoral footprint.
