Early Radiographic and Clinical Outcomes of Robotic‐arm‐assisted versus Conventional Total Knee Arthroplasty: A Multicenter Randomized Controlled Trial

Abstract

Objective

A robotic system was recently introduced to improve prosthetic alignment during total knee arthroplasty (TKA). The purpose of this multicenter, prospective, randomized controlled trial (RCT) was to determine whether robotic‐arm‐assisted TKA improves clinical and radiological outcomes when compared to conventional TKA.

Methods

One hundred and thirty patients who underwent primary TKA were enrolled in this prospective, randomized controlled trial, which was conducted at three hospitals. Five patients were lost to follow‐up 6 weeks after surgery. Therefore, 125 participants (63 in the intervention group and 62 in the control group) remained in the final analysis. The primary outcome was the rate at which the mechanical axis of the femur deviated by less than 3° from the mechanical axis of the tibia. This was evaluated by full‐length weight‐bearing X‐rays of the lower limb 6 weeks postoperatively. Secondary outcomes included operation times, 6‐week postoperative functional outcomes evaluated by the American Knee Society score (KSS) and the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), short form‐36 (SF‐36) health survey results, and the occurrence of adverse events (AEs) and serious adverse events (SAEs).

Results

At 6 weeks postoperatively, we found that the rate of radiographic inliers was significantly higher in the intervention group (78.7% vs 51.6%; p = 0.00; 95% confidence interval, 10.9% to 43.2%). The operation was significantly longer in the intervention group than in the control group (119.5 vs 85.0 min; p = 0.00). There were no significant differences in the 6‐week postoperative functional outcomes, SF‐36, AEs, and SAEs between the two groups. There were no AEs or SAEs that were determined to be “positively related” to the robotic system.

Conclusion

Robotic‐arm‐assisted TKA is safe and effective, as demonstrated in this trial.

The purpose of this multicenter prospective randomized controlled trial was to determine whether robotic‐arm‐assisted total knee arthroplasty (TKA) improves clinical and radiological outcomes when compared to conventional TKA. According to the results of the study, robotic‐arm‐assisted TKA is safe and effective, as demonstrated in this trial.

Introduction

A high incidence of knee osteoarthritis (KOA) is a major cause of increased disability among the elderly and of a rise in social costs. With the acceleration of population aging, the incidence of KOA is expected to rise steadily over the years. ¹ Total knee arthroplasty (TKA) is the most effective therapeutic option for severe KOA. ²

Previous research has indicated that problems, such as instability, periprosthetic infection, and pain, can arise after TKA. This has led to post‐TKA patient satisfaction rates of 80%–85%. ³ Further improvement of the effects of TKA and postoperative patient satisfaction has been a long‐standing goal of many arthroplasty surgeons; however, that has proven difficult to achieve.

Surgical technique, and errors in prosthesis placement, can significantly influence the long‐term therapeutic effect of arthroplasty. ⁴ Conventional TKA relies primarily on mechanical alignment methods, such as osteotomy templates, with intramedullary and extramedullary alignment of the femur and tibia. ⁵ The precision of prosthesis placement depends on the surgeon's proficiency in the pertinent techniques, and the anatomical structure of the femur and tibia. ⁶

Osteotomy templates and clamps are often used during conventional TKA procedures. Such mechanical alignment methods are cumbersome and lack precision in alignment, which decreases the precision of prosthesis installation. ⁷ The precision of osteotomy directly affects the implant‐bone interface and long‐term prosthesis survival, which have direct effects on the surgical outcome. ⁶ Minimally invasive, precise, individualized, and safe arthroplasty has become the goal of many surgeons. The harmonious integration of robotic‐arm‐assisted TKA with minimally invasive surgical techniques has led to the enhancement of surgical precision and safety; this can reduce the adverse events and dissatisfaction associated with TKA. ⁸

With the rapid advancement of medical imaging, virtual reality, and robotic techniques in recent years, robotic‐arm‐assisted surgery has become an important research direction in the field of advanced robotics. It is also increasingly favored by clinical practitioners, due to distinct advantages in operational flexibility, stability, and precision. ⁹ , ¹⁰ , ¹¹ , ¹²

Potential reasons for postoperative dissatisfaction and functional impairment in patients after TKA may include malalignment and joint instability. Robotic‐arm‐assisted TKA requires preoperative CT scans of the lower extremity to facilitate precise component alignment during surgery through intraoperative trackers and articular surface mapping enabled by computer navigation. Subsequently, the robotic‐arm‐assisted saw is used to execute the bone cuts according to the preoperative plan. Whether this intervention enhances the outcomes of TKA remains unknown. The purpose of this multicenter prospective randomized controlled trial (RCT) was to determine whether robotic‐arm‐assisted TKA improves radiological and clinical outcomes when compared to conventional TKA. Furthermore, we also aimed to evaluate the safety of robotic‐arm‐assisted TKA compared to conventional TKA, particularly focusing on complications specific to robotic assistance, including pin tract infection, pin‐site fracture, and patellar complications.

Materials and Methods

Study Design

The study was a prospective, multicenter, randomized controlled trial that evaluated the effectiveness and safety of robotic knee system‐assisted TKA through imaging results, operation times, postoperative function scores, and incidence rates of adverse events (AEs) and serious adverse events (SAE). It was approved by the Institutional Review Board of Peking University Third Hospital (IRB # 2022–134‐02), the First Affiliated Hospital of Shandong First Medical University (IRB # 2022‐QX‐S003‐01), and Chifeng Municipal Hospital (IRB # 2022‐LLSCGVK4‐101‐06). All patients provided written informed consent.

Patient Recruitment

From November 2022 to May 2023, a total of 130 patients were recruited and allocated into two groups in a 1:1 ratio using cluster randomization; 65 patients underwent robotic‐assisted TKA and 65 underwent conventional TKA. The inclusion criteria were as follows: (i) age ≥ 18 years and ≤ 80 years; (ii) KOA undergoing primary unilateral TKA; and (iii) written informed consent of willingness to complete all the assessments and potential interventions after receiving an oral and a written explanation of the study protocol. The exclusion criteria were as follows: (i) infection; (ii) severe systemic disease (such as severe diabetes, osteoporosis, muscle loss.); (iii) neuromuscular dysfunction of the lower limbs; (iv) allergies to metal implants; (v) participation in other clinical studies; (vi) prolonged fused knee joint without pain or deformity; (vii) inability to tolerate surgery on a systemic assessment; (viii) pregnant, breastfeeding, or expected birth during the clinical period; and (ix) other factors that affected the efficacy of observation in this study. All the operations were performed by experienced surgeons for the conventional and robotic‐assisted groups at the three hospitals. All patients who underwent TKA with the robotic‐assisted or conventional operations underwent radiological and clinical assessment.

Surgical Procedures and Postoperative Care

Each patient underwent either spinal anesthesia or general anesthesia according to the anesthesiologist's assessment. Intravenous cefuroxime sodium was given prior to inflation of the tourniquet. A standard medial parapatellar approach with patellar resurfacing was performed in all operations.

For the control group, distal femoral and proximal tibial osteotomies were guided by the positioning device and the osteotomy module. The trial components and spacers were installed, and then lower limb alignment and gap balance were checked.

For the intervention group, TKA was assisted by a knee navigation and positioning system developed by Beijing AKEC Medical Co., Ltd. (Beijing, China; specification model: OP‐RKL22). The intervention group required preoperative CT scans to plan the individuals' operation. The CT scans were used by the technician to plan the desired mechanical axis and implant sizes for the femur and tibia separately. Stabilization pins, navigation markers and bone movement monitors were placed and workspace checks conducted prior to making the incision. The robotic‐arm was used by the surgeon to cut the bone at the required alignment according to preoperative plan. Soft tissue releases were performed as required to balance the knee.

Prior to implanting the prosthesis, local infiltration anesthesia was administered. Intravenous tranexamic acid 1 g was administered before releasing the tourniquet, followed by irrigation and closure of the incision. The same cemented, posterior‐stabilized, fixed‐bearing joint prosthesis (Beijing AKEC Medical Co., Ltd., Beijing, China) was used in the experimental and control groups.

Postoperatively, both groups adopted the same regarding blood management, pain management, and rehabilitation plan. Physiotherapists, ward nursing staff and data collectors remained blinded for the duration of the study.

Outcome Measures

Baseline Information

Clinical information, including age, sex, height, weight, and other general information, was collected preoperatively. Other clinical information was collected and entered in the database preoperatively and postoperatively by independent investigators.

Primary Effectiveness Evaluation Indicator

The primary evaluation indicator of the present clinical study on TKA assisted by a knee navigation and positioning system was the proportion of participants whose angle of deviation of the mechanical axis of the femur from the mechanical axis of the tibia was ≤3°, as evaluated by full‐length weight‐bearing x‐rays of the lower limbs 6 weeks (±2 weeks) postoperatively.

Requirements for x‐ray imaging: ¹³ full‐length, weight‐bearing, anteroposterior X‐ray images of both lower limbs taken with the patient in a standing position. They included the hip joint, entire length of the femur, knee joint, entire length of the tibia and fibula, and ankle joint. Patients were instructed to stand upright on the X‐ray platform with their back against the platform, arms naturally hanging at the sides, knees extended as much as possible, and feet shoulder‐width apart and internally rotated by approximately 15°. This allowed approximately one‐third of the fibular head to overlap with the tibia, with the patella perpendicular and pointing forward.

The mechanical axes of the lower limbs were evaluated by an independent reviewer who was not involved in the surgeries.

Measurement of the Mechanical Axis of the Femur

The mechanical axis of the femur was defined as the line connecting the center point of the proximal joint (hip joint) to the center point of the distal joint (knee joint), as shown in Figure 1.

FIGURE 1.

Measurement of the mechanical axis of the femur.

The center point of the hip joint was defined as the center point of the circular femoral head, which was determined using Moses' circles. For the knee joint, the center point was defined as the apex of the intercondylar notch of the femur, which eliminated the need for measuring the width of bony or soft tissue.

Measurement of the Mechanical Axis of the Tibia

The mechanical axis of the tibia was defined as the line connecting the center point of the proximal joint (knee joint) to the center point of the distal joint (ankle joint), as shown in Figure 2.

FIGURE 2.

Measurement of the mechanical axis of the tibia.

The center point of the knee joint was defined as the center point of the tibial plateau, and the mid‐point of the talus width was measured to determine the center point of the ankle joint.

Measurement of the Angle between the Mechanical Axes of the Femur and Tibia

The angle between the mechanical axes of the femur and the tibia is known as the hip‐knee‐ankle (HKA) angle, ¹⁴ as shown in Figure 3.

FIGURE 3.

Measurement of the HKA angle.

Assessment criterion: patients were deemed to have a ≤ 3° mechanical axis deviation if the measured HKA angle did not exceed 180 ± 3°. The proportion of participants in whom the mechanical axis deviation angle was ≤3° in the full‐length weight‐bearing x‐ray of the lower limbs at 6 weeks (±2 weeks) postoperatively was calculated for both the intervention and control groups.

The calculation formulae were as follows:

$$\begin{array}{l}\text{Proportion for the intervention group}\\ =\begin{array}{l}\frac{\mathrm{No}.\text{of participants in the intervention group with}\mathrm{a}\text{mechanical axis deviation angle}\le 3^{°}}{\text{Total}\mathrm{no}.\text{of participants in the intervention group}}\times 100\%,\end{array}\end{array}$$

$$\begin{array}{l}\text{Proportion for the control group}\\ =\begin{array}{l}\frac{\mathrm{No}.\text{of participants in the control group with}\mathrm{a}\text{mechanical axis deviation angle}\le 3^{°}}{\text{Total}\mathrm{no}.\text{of participants in the control group}}\times 100\%.\end{array}\end{array}$$

Secondary Effectiveness Evaluation Indicators

Operation Time

The operation time for the control group was defined as the period from the surgical incision to the completion of suturing. For the intervention group, the surgery start time was defined as the period from the start of equipment operation or surgical incision (whichever occurred first), and the surgery end time was defined as the time of completion of suturing.

Knee Society Score (KSS)

The KSS is one of the most used scoring methods for the assessment of knee joint function. Based on the specific nature of arthroplasty, it employs assessor‐administered interviews and physical examination for the assessment of two major aspects, namely, the anatomy of the knee joint and its function. In other words, the tool aims to obtain information on the joint anatomy and biomechanics and gain an understanding of patients' functional recovery. The KSS was applied to the control and intervention groups.

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Score

The WOMAC is used to assess the severity of arthritis and the effectiveness of treatment, based on the pertinent signs and symptoms of patients. Designed specifically for the lower limbs, it assesses knee joint structure and function from three major aspects, namely pain, stiffness, and joint function. Assessments can be performed using the full version or specific items of the scale. The reliability, validity, and sensitivity of the WOMAC in knee joint assessment have already been objectively evaluated. ¹⁵

Short Form‐36 (SF‐36) Health Survey

The SF‐36 health survey is a generic measure, developed as part of the Medical Outcomes Study. The survey has been extensively used for the measurement of quality of life in general populations, evaluation of clinical trial outcomes, and assessment of health policies.

Safety Evaluation

Incidence of AEs

AEs were recorded throughout the clinical trial process, and the incidence rate of AEs was calculated.

The calculation formula was as follows:

$$\frac{\mathrm{No}.\text{of participants}\mathrm{who}\text{experienced}\mathrm{AEs}}{\text{Total}\mathrm{no}.\text{of participants in the trial}}\times 100\%.$$

Incidence of SAEs

SAEs were recorded throughout the clinical trial process, and the incidence rate of SAEs was calculated.

The calculation formula was as follows:

$$\frac{\mathrm{No}.\text{of participants}\mathrm{who}\text{experienced SAEs}}{\text{Total}\mathrm{no}.\text{of participants in the trial}}\times 100\%.$$

Statistical Analysis and Calculation of Sample Size

Quantitative indicators are described in terms of means, standard deviations, medians, minimum values, maximum values, lower quartiles, and upper quartiles, while qualitative indicators are described in terms of frequencies and percentages of the various categories. Comparisons of the general status of the two groups were performed by adopting appropriate methods based on indicator type. Quantitative data were compared using the independent‐sample t‐test or Wilcoxon rank‐sum test; qualitative data were compared with the Mann–Whitney U test, χ ² test, or Fisher's exact probability test, and ranked data were compared using the Wilcoxon rank‐sum test.

The subjects included in the analysis are categorized into the following statistical analysis datasets: Full analysis set (FAS), Per protocol set (PPS), and safety set (SS). FAS includes data from all subjects, excluding those with significant protocol deviations or no observation data after enrollment. PPS is a subset of the FAS, where each subject demonstrates good compliance and adherence to the protocol. SS should consist of all enrolled cases that have used the investigational device at least once and undergone at least one safety assessment. For missing primary efficacy data in the FAS, worst observation carried forward (WOCF) imputation will be applied. Missing non‐primary efficacy data in the FAS will not be imputed, and missing data in the PPS and SS will not be imputed.

In the present study, the proportion of participants in whom the angle of deviation between the mechanical axes of the femur and tibia was ≤3°, as evaluated by full‐length weight‐bearing X‐rays of the lower limbs 6 weeks postoperatively, was the primary evaluation indicator for the estimation of sample size. We performed a meta‐analysis of pertinent literature using a search strategy and a set of inclusion and exclusion criteria. A total of 18 articles, with the highest scores, were obtained from the screening process. ¹⁰ , ¹⁶ , ¹⁷ , ¹⁸ , ¹⁹ , ²⁰ , ²¹ , ²² , ²³ , ²⁴ , ²⁵ , ²⁶ , ²⁷ , ²⁸ , ²⁹ , ³⁰ , ³¹ , ³² The meta‐analysis results were obtained using a random effects model (see supplementary material). By setting a significance level of α = 0.025 (one‐sided) and β = 0.2, the power of the clinical trial was calculated, with the allocation ratio between the control and intervention groups being 1:1. The results of the power analysis indicated that a sample size of 55 was required. The final sample size was set as 65 after allowing for a dropout rate of 15%. Therefore, 65 participants each were included in the intervention and control groups.

Results

Participants

A total of 130 participants were included in this trial and randomly allocated to the intervention and control groups (65 participants each). There were two dropouts in the intervention group (dropout rate = 3.1%) and three in the control group (dropout rate = 4.6%); the difference in the dropout rate between the two groups was not statistically significant (p = 0.21, >0.05). A total of 125 participants were ultimately included in our analysis (63 in the intervention group and 62 in the control group).

Baseline Comparison

Demographic Data

Table 1 shows the results of the demographic data analysis. Differences in sex, age, height, and weight between the intervention and control groups were not statistically significant (p > 0.05).

TABLE 1.

Demographic data analysis.

Variable	Description	Intervention group	Control group	Test statistic	p
Sex	Male/Female	16/49	21/44	0.94 (χ 2 )	0.33
Age (years)	Mean (SD)	68.1 (5.0)	67.4 (5.5)	0.75 (tֵ)	0.46
Height (cm)	Mean (SD)	161.4 (6.1)	161.5 (6.6)	−0.11 (tֵ)	0.91
Weight (kg)	Mean (SD)	70.0 (9.9)	71.5 (10.5)	−0.86 (tֵ)	0.39

Medical History Data

Table 2 shows the results of the medical history data analysis. The differences in disease course, severity, preoperative score, and comorbidities between the intervention and control groups were not statistically significant (p > 0.05).

TABLE 2.

Medical history data analysis.

Variable	Description	Intervention group	Control group	Test statistic	p
Disease course (months)	Mean (SD)	111.7 (75.4)	107.2 (66.2)	0.36 (tֵ)	0.72
KSS	Mean (SD)	43.8 (11.2)	43.9 (12.6)	−0.06 (tֵ)	0.95
WOMAC score	Mean (SD)	50.8 (12.3)	50.4 (11.3)	0.23 (tֵ)	0.82
SF‐36 health survey	Mean (SD)	339.1 (79.7)	327.7 (61.4)	0.91 (tֵ)	0.36
Severity				1.20 (χ 2 )	0.55
	Mild	0 (0.0%)	1 (1.5%)
	Moderate	21 (32.3%)	23 (35.4%)
	Severe	44 (67.7%)	41 (63.1%)
Comorbidity		60 (92.3%)	56 (86.2%)	1.28 (χ 2 )	0.26
Allergic history		8 (12.3%)	5 (7.7%)	0.77 (χ 2 )	0.38

Surgical Records

Table 3 shows the results of the analysis of the surgical records. The differences in anesthetic methods and blood loss between the intervention and control groups were not statistically significant (p > 0.05).

TABLE 3.

Surgical data analysis.

Variable	Description	Intervention group	Control group	Test statistic	p
Anesthetic method				0.28 (χ 2 )	0.60
	General anesthesia	29 (44.6%)	32 (49.2%)
	Intravertebral anesthesia	36 (55.4%)	33 (50.8%)
	Other	0 (0.0%)	0 (0.0%)
Blood loss (ml)	Mean (SD)	93.5 (72.9)	74.5 (83.2)	1.38 (tֵ)	0.17

Primary Evaluation Indicator

Table 4 shows the femoral‐tibial angles and the results of the deviation analysis. It shows that the proportion of participants who fulfilled the deviation criteria was 78.7% in the intervention group and 51.6% in the control group, with the proportion being significantly different between the two groups (p = 0.00, <0.05). The difference in the proportion of participants fulfilling the deviation criteria between the groups was 27.1%, with the 95% confidence interval of the difference being 10.9% and 43.2%.

TABLE 4.

Femoral‐tibial angles and deviation at 6 weeks postoperatively.

Variable	Description	Intervention group	Control group	Test statistic	p
	N (Nmiss)	61 (4)	62 (3)
Femoral‐tibial angle (°)	Mean (SD)	177.3 (1.9)	177.0 (2.2)	0.77 (tֵ)	0.44
Deviation		13 (21.3%)	30 (48.4%)	9.91 (χ 2 )	0.00

Secondary Effectiveness Evaluation Indicators

Operation Time

The average operation time was 111.9 ± 27.8 min for the intervention group and 85.0 ± 18.9 min for the control group, with the difference between the two groups being statistically significant (p < 0.01).

Clinical Outcome Scores

Table 5 shows the results of the analysis of the 6 ± 2‐week postoperative clinical outcome scores, including KSS, WOMAC scores, and SF‐36 health survey. The results indicate that the difference in clinical outcome scores between the intervention and control groups was not statistically significant (p > 0.05).

TABLE 5.

Clinical outcome scores at 6 weeks postoperatively.

Variable	Description	Intervention group	Control group	Test statistic	p
	N (Nmiss)	63 (2)	62 (3)
KSS	Mean (SD)	87.6 (9.7)	89.1 (9.2)	−0.88 (tֵ)	0.38
WOMAC score	Mean (SD)	16.2 (9.1)	14.4 (8.0)	1.13 (tֵ)	0.26
SF‐36 health survey	Mean (SD)	540.3 (103.5)	550.7 (93.0)	−0.59 (tֵ)	0.55

Safety Evaluation Indicators

The incidence of AEs was 13.8% in the intervention group and 20.0% in the control group; the difference in the incidence between the two groups was not statistically significant (p = 0.35, >0.05).

The incidence of SAEs was 0.0% for the intervention group and 1.5% for the control group; the difference in the incidence between the two groups was not statistically significant (p = 0.32, >0.05).

All AEs and SAEs were unrelated to the surgical instruments.

Discussion

The study evaluated and compared the radiological and clinical outcomes of both robotic‐arm‐assisted and conventional TKA using the specific implant system. Our study revealed that the precision of the alignment of the mechanical axes was significantly better in the robotic‐arm‐assisted TKA. We found excellent clinical and safety outcomes involving both robotic and conventional TKA, with no significant difference between the two groups.

Better Radiographic Outcomes

Robotic systems, developed based on three‐dimensional (3D)‐reconstructed patient models, utilize software for preoperative planning and design of optimal surgical protocols. This enables effective enhancement of the predictability of surgery. ³³ The use of a knee navigation and positioning system in TKA allows for accurate matching of the preoperative imaging data of patients to the anatomical structures observed on the operating table. During the surgery, the positions of surgical instruments are displayed on patient images, and updated real‐time through tracking, and the robotic arm can assist surgeons in positioning. Kayani et al. reported that surgical assistance provided through the 3D positional information and tracking in robotic‐arm‐assisted TKA led to higher accuracy in coronal, sagittal, and rotational alignment, and better joint line restoration. ³⁴ Robotic‐arm‐assisted TKA can also reduce iatrogenic bone and periarticular soft tissue damage, thereby reducing physical pain in surgical patients to the greatest possible extent. ³⁵

The long‐term effectiveness of TKA is largely dependent on the precision of the alignment of the mechanical axes of the femur and tibia. Currently, the gold standard for assessment involves measuring the angle between the mechanical axes of the femur and tibia to determine whether it exceeds ±3°. ¹² Jeffery et al. performed an 8‐year follow‐up study of 115 patients who had undergone TKA and found that patients in whom the angle between the mechanical axes of the femur and tibia was within ±3° exhibited a significantly lower rate of postoperative loosening compared with patients with lower limb mechanical axis deviation exceeding ±3°. ¹⁴ Therefore, the proportion of participants with lower limb mechanical axis deviation was selected as the primary effectiveness evaluation indicator for the present study. Our results revealed that the intervention group had a higher proportion of patients who fulfilled the deviation criterion than the control group, with the proportions of the two groups being significantly different. The difference in the proportion of participants fulfilling the deviation criteria between the groups was 27.1% and the lower limit of the corresponding 95% confidence interval was greater than 0, demonstrating that the results of the intervention group were significantly superior to those of the control group in fulfilling the deviation criterion. Robot navigation and positioning techniques can assist physicians in reducing the errors associated with manual operation, and in obtaining satisfactory weight‐bearing x‐rays of the lower limbs for measuring the angle of deviation of the mechanical axis of the femur from the mechanical axis of the tibia. The benefits were more pronounced with inexperienced physicians. ³⁶

Longer Operation Time

The majority of current studies have indicated that robotic‐arm‐assisted TKAs have longer operation times. ³⁷ Our results revealed that the average operation time of the intervention group was significantly longer than that of the control group, agreeing with previous research. This may be attributed to the additional steps in the surgical procedures of the intervention group, including pin placement, navigation registration, and repeated angle verification. A meta‐analysis by Zhang et al. ³⁸ showed that robotic‐arm‐assisted TKA had a shorter learning curve and an operation time that may be close to, or even shorter than, that of conventional surgery. A study of 146 surgeons at 30 hospitals indicated that 64% of surgeons could achieve the same operation time as that of conventional surgery after completing 12 robotic‐arm‐assisted TKA procedures. ³⁹

Similar Clinical Outcomes

The present study has shown that the differences in the 6 ± 2‐week postoperative KSS, WOMAC score, and SF‐36 health survey score, between the intervention and control groups, were not statistically significant. A meta‐analysis by Agarwal et al. ⁴⁰ reported that patients who underwent robotic‐arm‐assisted TKA had better postoperative clinical function scores than those who underwent conventional surgery. However, the results of another meta‐analysis indicated that robotic‐arm‐assisted TKA did not provide better overall clinical outcomes than conventional TKA. ³⁷ Considering the minimal clinically important difference (MCID) of the clinical outcome scores, ⁴¹ , ⁴² , ⁴³ we believe that robotic‐arm‐assisted system does not improve early knee joint clinical function in patients.

Good Safety Profile

Robotic‐arm‐assisted TKA also demonstrated a good safety profile. The incidence rates of AEs and SAEs did not differ significantly between the intervention and control groups. There were also no occurrences of AEs and SAEs that were determined to be positively related to the navigation and positioning system used in the present study, which suggests that the system is safe in clinical settings.

Limitations

One significant limitation of our study was the lack of patient blinding, as participants undergoing robotic‐arm‐assisted TKA were required to undergo a preoperative CT scan and be informed of this before enrolling in the study. Another limitation is that the assessors were blinded to the intervention group; however, the majority of outcome measures assessed in this study were subjective patient‐reported outcomes. Therefore, further large‐scale, randomized controlled studies with long‐term follow‐up will be needed for validation.

Conclusion

In conclusion, the use of robotic systems for assistance in TKA enhances the precision of osteotomy and postoperative alignment, while demonstrating a good safety profile. Therefore, such systems can potentially have a broader range of applications in clinical practice.

Conflict of Interest Statement

The authors declare that they have no conflicts of interest.

Ethical Statement

Study approval was obtained from the Institutional Review Board of Peking University Third Hospital, the First Affiliated Hospital of Shandong First Medical University, and Chifeng Municipal Hospital. All participants signed informed consents for the surgery.

Author Contributions

All authors had full access to the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Conceptualization, F.L. and H.T.; methodology, X.G. and Y.Z.; investigation, M.Z., Y.L., X.L., F.G., M.Z. and Y.L.; formal analysis, X.G. and Y.Z.; resources, Z.L., H.C., M.Z. and Z.S.; writing—original draft, X.G. and Y.Z.; writing—review and editing, F.L., H.T., X.G. and Y.Z.; visualization, Y.Z.; supervision, F.L.; funding acquisition, X.G.