Advantages of the experience of navigation when starting manual total knee arthroplasty.

Abstract

To evaluate how the accuracy of coronal-plane bone cutting and operative time may be affected by the experience of navigated total knee replacement (TKR) in starters of manual TKR. We analyzed 30 cases of navigated TKR performed in the early years (group 1), 30 consecutive cases of navigated TKR performed after experiencing more than 100 cases of navigated TKR (group 2), and the initial 30 consecutive cases of manual TKR (group 3). Postoperative mechanical hip-knee-ankle (mHKA) angle, mechanical medial proximal tibial angle (mMPTA), and mechanical lateral distal femoral angle (mLDFA) were measured. Bone cutting was aimed at mHKA angle of 0°, mMPTA of 90°, and mLDFA of 90°. We have set the tolerance of absolute value of errors in mHKA angle, mMPTA and mLDFA as 0 ± 3°. Comparative analysis of tourniquet times have been performed. Postoperative absolute error values of mHKA angle, mMPTA, and mLDFA were 2.78 ± 3.53°, 1.06 ± 1.91°, and 1.44 ± 1.90° in group 1; 1.18 ± 1.32°, 1.20 ± 1.49°, and 0.98 ± 1.09° in group 2; and 2.11 ± 2.49°, 1.35 ± 0.62°, and 1.92 ± 2.85° in group 3. Tourniquet times were 67.50 ± 21.50 min in group 1, while group 2 and group 3 showed tourniquet times of 51.87 ± 12.00 and 52.00 ± 15.00 min, respectively. In starters of manual TKR, previous experience of performing navigated TKR may help the error values during femoral and tibial bone cutting to fall within the values similar to the median error value of navigated TKR. It may also help to reduce the operative time of manual TKR similar to the operative time of and experienced surgeon with over 100 cases of navigated TKR.