The early learning curve of OrthoPilot computer navigation assisted total knee arthroplasty / 中华骨科杂志

ABSTRACT

Objective:To explore the early learning curve of OrthoPilot navigation assisted total knee arthroplasty (TKA).Methods:Data of 40 consecutive cases of OrthoPilot navigation assisted TKA completed by the same surgical team in our department were retrospectively analyzed. According to the operation order, 40 cases were divided into the original phase group (the first 20 cases) and the subsequent phase group (the second 20 cases). In original phase group, the average age was 69.85±6.86 years with mean body mass index 24.10±2.88 kg/m 2, preoperative HSS score 48.80±5.33, preoperative knee ROM 87.05°±11.02° and preoperative alignment deviation of 7.40°±5.59°. In subsequent phase group, the average age was 66.65±7.92 years with mean body mass index 22.85±3.15 kg/m 2, preoperative HSS score 49.00±5.47, preoperative knee ROM 85.80°±11.65° and preoperative alignment deviation of 8.22°±5.21°. Perioperative data such as operative duration, incision length, hemoglobin drop and postoperative hospital stay, radiographic outcomes including hip-knee-ankle angle (HKAA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), sagittal femoral component angle (sFCA), sagittal tibial component angle (sTCA), joint line convergence angle (JLCA), and functional scores were compared between the two groups. Results:All 40 cases were followed up for 24-33 months (mean, 27.38± 2.73 months). No severe postoperative complications such as infection and loosening occurred during the follow-up. The mean operative duration was 112.35±25.49 min in original phase group versus 82.10±10.96 min in subsequent phase group ( P< 0.05). The durations of tibial cutting was 11.95±3.27 min in original phase group versus 7.35±2.23 min in subsequent phase group ( P< 0.05); the femoral planning + cutting time was 20.95±6.91 min in original phase group versus 16.60±4.78 min in subsequent phase group, and trial + prosthesis implantation time was 39.65±7.72 min in original phase group versus 25.10±5.72 min in subsequent phase group,which was significantly higher in original phase group. There was no significant difference in other perioperative data such as incision length, hemoglobin drop and postoperative hospital stay between the two groups. As for radiographic outcomes, there was no statistical difference between the two groups in the postoperative angular deviation of HKAA (0.70°±0.80° vs. 0.80°±1.06°), mLDFA (0.89°±0.91° vs. 1.00°±0.86°), mMPTA (0.77°±0.53° vs. 0.76°±1.03°), sFCA (0.73°±0.48° vs. 0.87°±1.06°), sTCA (0.95°±0.58° vs. 1.16°±1.14°) and JLCA (0.27°±0.25° vs. 0.39°±0.18°). In original phase group, the HSS scores preoperative and 3 days postoperative were 48.80±5.33 and 60.05±5.10 respectively, and those in subsequent phase were 49.00±5.47 and 60.75±4.47 respectively, and both groups showed satisfactory functional recovery. There was no significant difference in HSS scores at all follow-up time points between two phases, as well as ROM (113.20°±9.82° vs. 113.50°±12.44°) and FJS-12 scores (78.00°±10.98° vs. 76.65°±10.29°) at 2 years postoperatively. Conclusion:In this study, we described a time-related early learning curve for OrthoPilot navigation-assisted TKA, in which the operative duration tended to be shorter after the first 20 cases. However, benefiting from good operative accuracy and repeatability, satisfactory radiographic and functional outcomes can be obtained in early stage of the learning curve.