Accuracy of Femoral Component External Rotation with all Burr Robotic Assisted Total Knee Arthroplasty.

Introduction: External rotation of femoral component is controversial in Total knee arthroplasty (TKA). The aim of our study is to assess the precision of femoral component external rotation in Robotic Assisted All Burr TKA.

Materials and methods: This is a prospective study of 30 cases who underwent All Burr Robotic Assisted TKA at our institute, RNH hospital. Inclusion criteria were primary and secondary osteoarthritis of the knee and exclusion criteria were revision and partial knee replacement. On Navio robotic system femoral external rotation was planned as per medio-lateral flexion gap balancing and executed with burr. Post-operative CT scan was done in all patients to assess intra-operative planned femoral external rotation.

Results: Out of 30 cases, 20 were female and 10 were male. Mean age was 66.06±7.43 years. On Navio the planned external rotation of femoral component was 2.86±1.16. Average of femoral component external rotation on postoperative CT scan was 3.11±1.16. The mean deviation of achieved femoral component external rotation from planned external rotation was -0.24 to ±0.28. Only 37% patients required 3° external rotation. Correlation between planned and achieved femoral component external rotation was significant, positive and very strong as indicated by r=0.97 and p=0.0001.

Conclusion: All Burr Robotic Assisted TKA provides near accurate femoral component external rotation as planned on Navio with deviation of less than 0.3° between planned and achieved external rotation.