Vermue Hannes, Arnout Nele, Tampere Thomas, Stroobant Lenka, Dereu Alexander, Victor Jan
Department of Orthopedic Surgery, Ghent University Hospital, Ghent, Belgium.
Clin Orthop Relat Res. 2025 Oct 1;483(10):1866-1874. doi: 10.1097/CORR.0000000000003505. Epub 2025 Apr 16.
Joint stability is a major factor associated with success after TKA. However, most assistive technologies, such as robotic-assisted TKA, do not incorporate a standardized laxity assessment. To address this gap, we opted to perform a randomized controlled trial comparing the results of a manual versus a robot-assisted TKA system with standardized laxity assessment.
QUESTIONS/PURPOSES: (1) Does robot-assisted TKA with a standardized laxity assessment provide superior patient-reported outcomes compared with conventional TKA with a manual tensioner, and does it result in a higher percentage of patients achieving the patient acceptable symptom state (PASS) thresholds 2 years after surgery? (2) Does robot-assisted TKA with a standardized laxity assessment provide different coronal alignment or coronal laxity compared with conventional TKA with a manual tensioner after surgery?
This was a prospectively registered randomized trial performed at a single center in Belgium. Patients with end-stage knee osteoarthritis unresponsive to conservative treatment were eligible. Exclusion criteria included severe deformity, limited ROM, prior fractures, infection, ligament insufficiency, and neurologic conditions. Between September 2020 and August 2022, we randomized 60 patients to receive TKA either with a manual tensiometer (n = 30) or a robotic-assisted TKA with an imageless system using a standardized laxity system (distraction of the tibiofemoral joint with 80N throughout ROM; n = 30). Of those, 100% (30 of 30) and 90% (27 of 30) of patients were available for follow-up at 2 years in the robotic-assisted and conventional groups, respectively. In both groups, a posterior stabilized implant was used. Patient-reported outcome measures (Knee Society Score [KSS], WOMAC, and 5-level EuroQol 5-domain scores) were obtained preoperatively and at 2 years postoperatively. Coronal alignment and implant position were evaluated on full-leg weightbearing radiographs. Stress radiographs were obtained to assess coronal laxity in 10° of flexion. There were no differences between the groups in baseline characteristics of age, BMI, side, gender, hip-knee-ankle axis, ROM, or patient-reported outcome measures. To account for multiple comparisons in this study, a Bonferroni correction was applied. All differences between both groups were evaluated considering minimum clinically important difference values for patients who have undergone TKA. The power analysis indicated 80% power to detect a clinically meaningful difference of 9.7 points in KSS function score, with an alpha of 0.05.
We found no clinically important differences in patient-reported outcomes 2 years after surgery between the conventional and the robotic group (for example, the KSS function score in those groups was 66 ± 20 versus 74 ± 24, respectively, mean difference 8 [95% confidence interval (CI) -3 to 21]; p = 0.18), and no difference in the proportion of patients in those groups who achieved the PASS on any outcomes score (for example, the percentage of patients achieving the PASS for the WOMAC was 4% [1 of 27] versus 3% [1 of 30], respectively, OR 0.9 [95% CI 0 to 15]; p > 0.99). Likewise, there were no differences in postoperative hip-knee-ankle axis between the conventional and the robotic groups, respectively (1° ± 2° varus versus 1° ± 3° varus; p > 0.99) or in coronal-plane laxity (6° ± 3° versus 7° ± 2° in the conventional cohort; p = 0.73).
Based on the absence of clinically important differences in outcome scores or any differences in the proportion of patients who achieved the PASS on those scores (as well as the absence of meaningful differences in alignment or soft tissue tension), we recommend against the routine use of robotic TKA with objectified laxity assessment because it adds costs and time to these procedures without delivering benefits that patients might perceive. Future studies might, however, be able to identify patient-specific laxity targets to improve patient outcomes.
Level I, therapeutic study.
关节稳定性是全膝关节置换术（TKA）后成功的主要相关因素。然而，大多数辅助技术，如机器人辅助TKA，并未纳入标准化的松弛度评估。为填补这一空白，我们选择进行一项随机对照试验，比较手动与机器人辅助TKA系统并采用标准化松弛度评估的结果。
问题/目的：（1）与使用手动张力器的传统TKA相比，采用标准化松弛度评估的机器人辅助TKA是否能提供更优的患者报告结局，并且术后2年达到患者可接受症状状态（PASS）阈值的患者比例是否更高？（2）与使用手动张力器的传统TKA相比，采用标准化松弛度评估的机器人辅助TKA术后在冠状位对线或冠状位松弛度方面是否存在差异？
这是一项在比利时一个中心进行的前瞻性注册随机试验。符合条件的患者为对保守治疗无反应的终末期膝骨关节炎患者。排除标准包括严重畸形、活动范围受限、既往骨折、感染、韧带功能不全和神经疾病。在2020年9月至2022年8月期间，我们将60例患者随机分为两组，一组接受使用手动张力计的TKA（n = 30），另一组接受使用标准化松弛度系统的无图像系统的机器人辅助TKA（在整个活动范围内用80N牵开胫股关节；n = 30）。其中，机器人辅助组和传统组分别有100%（30例中的30例）和90%（30例中的27例）的患者在术后2年可进行随访。两组均使用后稳定型植入物。术前和术后2年获取患者报告的结局指标（膝关节协会评分[KSS]、WOMAC和5级欧洲五维健康量表评分）。在全腿负重X线片上评估冠状位对线和植入物位置。获取应力X线片以评估10°屈曲位时的冠状位松弛度。两组在年龄、体重指数、手术侧、性别、髋-膝-踝轴线、活动范围或患者报告的结局指标等基线特征方面无差异。为考虑本研究中的多重比较，采用了Bonferroni校正。两组之间的所有差异均根据接受TKA患者的最小临床重要差异值进行评估。功效分析表明，检测KSS功能评分中具有临床意义的9.7分差异的功效为80%，α值为0.05。
我们发现，术后2年传统组和机器人组在患者报告的结局方面无临床重要差异（例如，两组的KSS功能评分分别为66±20和74±24，平均差异为8[95%置信区间（CI）-3至21]；p = 0.18），并且两组中在任何结局评分上达到PASS的患者比例无差异（例如，WOMAC达到PASS的患者百分比分别为4%[27例中的1例]和3%[30例中的1例]，OR为0.9[95%CI 0至15]；p>0.99）。同样，传统组和机器人组术后髋-膝-踝轴线也无差异（内翻1°±2°对1°±3°；p>0.99）或冠状面松弛度无差异（传统队列中为6°±3°对7°±2°；p = 0.73）。
基于结局评分无临床重要差异，或在这些评分上达到PASS的患者比例无差异（以及对线或软组织张力无有意义差异），我们不建议常规使用具有客观松弛度评估的机器人TKA，因为这会增加这些手术的成本和时间，且未带来患者可能感知到的益处。然而，未来的研究或许能够确定针对特定患者的松弛度目标以改善患者结局。
I级，治疗性研究。
