Objective: To analyze the accuracy of prosthesis size selection in Naton robot-assisted medial unicondyle knee arthroplasty by comparing the actual prosthesis size used during operation and the preoperative planning.
Methods: The clinical data of 100 patients (110 knees) who underwent Naton robot-assisted medial unicondylar knee arthroplasty between June 2023 and July 2024 was retrospectively analyzed, including 47 knees on left side and 63 knees on right side. There were 37 males (40 knees) and 63 females (70 knees) with a mean age of 65.4 years (range, 59-71 years). Body mass index was 22.2-28.6 kg/m 2 (mean, 25.4 kg/m 2). The disease duration ranged from 1 to 8 years (mean, 3.4 years). Preoperative planning was performed by Naton robotic surgical system based on lower limb CT data. The final prosthesis size after osteotomy was recorded and compared with the preoperative plan to analyse whether it was consistent with the preoperative plan, as well as the situation of knee flexion and extension gaps (<0.5 mm, >2.0 mm) corresponding to the different models of prostheses.
Results: During operation, 5 patients (5 knees) were treated with traditional UKA due to mechanical arm failure, software obstacles, significant bone amputation bias, or loose reference frame, and were excluded from the final analysis. The remaining 95 patients (105 knees) successfully received Naton robot-assisted surgery, and no related complications occurred. The prosthesis size was consistent with the preoperative plan in 101 knees (96.2%) on the femur side, 100 knees (95.2%) on the tibia side, and 97 knees (92.4%) on both femur and tibia sides. The prosthesis size was inconsistent in 3 cases (2.86%) on the femur side alone, 4 cases (3.81%) on the tibial side alone, and 1 case (0.95%) on both femur and tibial sides. Among the prostheses with different models, the flexion and extension gaps were less than 0.5 mm in 3 knees, the flexion gap was less than 0.5 mm and the extension gap was more than 2.0 mm in 3 knees, and the flexion gap was more than 2.0 mm and the extension gap was less than 0.5 mm in 2 knees.
Conclusion: The accuracy of prosthesis size selection for Naton robot-assisted medial unicondylar knee arthroplasty is relatively high.
目的: 通过比较术中实际使用假体型号与术前规划差异，分析Naton机器人辅助膝关节内侧单髁置换术假体型号选择的准确性。.
方法: 回顾性分析2023年6月—2024年7月行Naton机器人辅助膝关节内侧单髁置换术且符合选择标准的100例（110膝）患者临床资料。其中男37例（40膝），女63例（70膝）；年龄59～71岁，平均65.4岁。左侧47膝，右侧63膝。身体质量指数22.2～28.6 kg/m 2，平均25.4 kg/m 2。病程1～8年，平均3.4年。术前均采用Naton机器人手术系统基于下肢CT数据进行手术方案规划、确定假体型号，记录术中截骨后最终使用假体型号并与术前规划进行比较是否一致，以及型号不一致假体对应膝关节屈、伸间隙（<0.5 mm、>2.0 mm）情况。.
结果: 术中5例（5膝）因机械臂故障、软件障碍、截骨量明显偏倚或参考架松动等原因改为传统UKA，排除最终分析；余95例患者（105例膝）均顺利接受机器人置换手术，均无相关并发症出现。术中股骨侧假体型号与术前规划一致101膝（96.2%）、胫骨侧一致100膝（95.2%）、股骨及胫骨侧均一致97膝（92.4%）；其中单独股骨侧假体型号不一致3膝（2.86%），单独胫骨侧不一致4膝（3.81%），股骨侧与胫骨侧型号均不一致1膝（0.95%）。假体型号不一致的膝关节中，屈、伸间隙均<0.5 mm 3膝，屈曲间隙<0.5 mm、伸直间隙>2.0 mm 3膝，屈曲间隙>2.0 mm、伸直间隙<0.5 mm 2膝。.
结论: 膝关节内侧单髁置换术前采用Naton机器人辅助规划假体型号准确性较高。.
Keywords: Knee joint; preoperative planning; prosthesis size; robots; unicompartmental knee arthroplasty.