Robotic-assisted versus manual total hip arthroplasty in obese patients: a retrospective case-control study

There is No Increased Pulmonary Risk Following Total Hip Arthroplasty in Patients Who Have Obstructive Sleep Apnea Without Underlying Lung Disease

BACKGROUND

Obstructive sleep apnea (OSA) is a frequent comorbidity. The current study evaluated whether there is a difference in the perioperative outcome after total hip arthroplasty (THA) in patients who had a low to moderate risk for OSA and high risk for OSA, respectively.

METHODS

After excluding patients who had concomitant lung disease (chronic obstructive pulmonary disease, asthma, or lung fibrosis) and those missing a STOP-Bang Score, 1,141 THA patients who had OSA were included in this retrospective study. Patients at low to moderate risk for OSA (STOP-Bang Score 0 to 4) and patients at high risk for OSA (STOP-Bang Score 5 to 8) were compared, and SpO2 (oxygen saturation) drops < 90% as well as readmission rates were compared between patients who did and did not use continuous positive airway pressure (CPAP).

RESULTS

There was no difference in the risk of SpO2 drop below 90% (1 versus 0%, P = 0.398) and readmission rate (2 versus 2%, P = 0.662) between patients who had low to moderate OSA risk (327 THA) and high OSA risk (814 THAs). There was no difference in SpO2 (P > 0.999) and a decrease in oxygen flow rate from the postanesthesia care unit to the morning of the first postoperative day. A CPAP device was used by 41% (467 of 1,141) of patients. There were no differences in SpO2 drop < 90% (0 versus 0%, P = 0.731) and readmission rate (2 versus 2%, P = 0.612) between patients who did and did not use a CPAP machine.

CONCLUSIONS

The current study showed no difference in perioperative outcomes between OSA patients undergoing THA who had a low STOP-Bang Score and patients who had a high STOP-Bang Score, regardless of the use of a CPAP machine. These data suggest that an elevated Stop-Bang Score does not indicate an increased perioperative risk for OSA patients when deciding on outpatient discharge.

Robotic-assistance is associated with better joint outcomes compared to conventional techniques in surgically routine total hip arthroplasty: a propensity-matched large database study of 3948 patients

INTRODUCTION

The outcomes of total hip arthroplasty (THA) are highly dependent upon the restoration of native hip biomechanics and optimal component positioning. Robotic technologies for THA have rapidly improved the accuracy of component positioning and maintaining the planned center of rotation. While robotic-assisted THA (RA-THA) has primarily been employed in surgically intricate cases, its potential benefits in scenarios of diminished surgical complexity remain less explored. Therefore, the purpose of this study was to assess the odds of developing systemic and joint complications following RA-THA in cases of reduced surgical complexity.

METHODS

A retrospective cohort study was conducted using the TriNetX national database to identify patients who underwent primary THA (Current Procedural Terminology code 27,130) and more specifically RA-THA identified by ICD-10-PCS code 8E0Y0CZ and Healthcare Common Procedure Coding System code S2900 from 2013 to 2022. One-to-one propensity score matching was conducted to generate 2 cohorts: (1) RA-THA and (2) conventional THA (C-THA). Systemic and joint complications were assessed at the 30-day, 90-day, 1-year, and 5-year postoperative periods.

RESULTS

Patients undergoing RA-THA had a lower risk of needing a revision THA at the 90-day, 1-year, and 5-year time points. RA-THA was associated with a lower risk of prosthetic dislocation at 90 days and 1 year and prosthetic pain at 1 year and 5 years. Dislocation of the hip or fracture of the femur was significantly lower in the RA-THA cohort at all four-time points. Patients undergoing RA-THA had a lower risk of developing deep vein thrombosis at 5 years.

CONCLUSION

These findings suggest that RA-THA has comparable systemic and less joint complication risks at 30-day to 5-year timepoints between RA-THA and C-THA. Future studies with large sample sizes and long-term follow-up are needed to understand the patient-reported outcomes and functional outcomes of RA-THA for cases with reduced surgical complexity.

Effect of Early Postoperative Gait Parameters After Total Hip Arthroplasty on Forgotten Joint Score-12 at 2-Year Follow-Up

Purpose: This study aimed to elucidate the relationship between early postoperative gait parameters after total hip arthroplasty (THA) and the Forgotten Joint Score-12 (FJS-12) score at the 2-year follow-up after surgery. In addition, the cutoff gait parameter values for predicting discomfort using specific FJS-12 subitems were evaluated. Methods: Among 313 patients who underwent THA between April and December 2019, 44 (14.0%) who responded to the FJS-12 questionnaire at 2 years postoperatively were included in this study. Gait parameters, including walking speed, stride length, and their coefficients of variation (CVs), were measured at 13.8 ± 3.6 (mean ± standard deviation) days postoperatively. The FJS-12 was used to evaluate patients at 2 years after surgery. The correlation between the FJS-12 score and gait parameters was analyzed using Spearman's rank correlation coefficient. To determine the significant predictors of the FJS-12 score, multiple regression analysis was performed after adjusting for age as a covariate. Furthermore, receiver operating characteristic curves were used to determine the cutoff gait parameter values for predicting discomfort using specific FJS-12 subitems. Results: The FJS-12 score was significantly positively correlated with walking speed (rs = 0.38, p < 0.05) and stride length (rs = 0.51, p < 0.01). Meanwhile, the FJS-12 score was significantly negatively correlated with the CVs of walking speed (rs = -0.34, p < 0.05) and stride length (rs = -0.35, p < 0.05). Based on multiple regression analysis, stride length was a significant predictor of discomfort assessed using the FJS-12 score (β = 0.48, p < 0.01). According to the receiver operating characteristic curves, the cutoff stride length values for predicting discomfort using the FJS-12 subitems 9, 10, 11, and 12 showed moderate accuracy (area under the curve > 0.7). Conclusions: Improved walking ability of patients who underwent THA through early rehabilitation is linked to joint discomfort and patient satisfaction in daily life 2 years postoperatively.

Robotic-Assisted Total Hip Arthroplasty Provides Greater Implant Placement Accuracy and Lower Complication Rates, but Not Superior Clinical Results Compared to the Conventional Manual Approach: A Systematic Review and Meta-Analysis

BACKGROUND

Accurate component placement plays a critical role in the outcome of total hip arthroplasty (THA). Robotic-assisted THA (R-THA) has emerged as an option to optimize this aspect compared to the conventional manual THA (C-THA). The aim of this meta-analysis was to analyze the studies comparing R-THA and C-THA. The hypothesis was that the use of robotic technology could improve component positioning, but this advantage may not translate into clinically relevant benefits.

METHODS

The literature search was conducted on three databases (PubMed, Cochrane Library, and Web of Science) in January 2024. The screening process and analysis were conducted separately by two independent observers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The inclusion criteria were comparative studies, English language, no time limitation, and focusing on the comparison of R-THA and C-THA. Among the 1,883 articles retrieved, 38 studies (10,055 patients) were included. The meta-analysis covered radiological outcomes, clinical outcomes, perioperative parameters, complications, and revisions. The quality of each article was assessed using the "Downs and Black's checklist for measuring quality".

RESULTS

Robotic THA provided superior radiological results compared to C-THA in terms of acetabular cup placement within the Lewinnek safe zone (P < 0.01) and horizontal change of the rotation center (P = 0.03). No statistically significant difference was obtained in terms of clinical scores between the two approaches, including Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index, Forgotten Joint Score, and Merle d'Aubigné Hip Score. Robotic THA showed longer operative time (P < 0.01), but lower complication rates (P = 0.04). No difference was obtained in terms of intraoperative blood loss and revision rates.

CONCLUSIONS

The results of this meta-analysis suggest that R-THA can provide more accurate cup placement and better restoration of the native hip anatomy while reducing complication rates compared to C-THA. However, these benefits did not translate into clinical differences in terms of patient-reported outcomes between the two approaches, and R-THA required longer operative time. While the overall results suggest some benefits with the robotic technology, future studies should investigate if further technical improvements will translate into clinically relevant benefits for patients undergoing THA.

[Impact of robot assistance on restoration of limb length and offset distance in total hip arthroplasty]

Objective

To analyze the impact of robot assistance on the restoration of limb length and offset distance in total hip arthroplasty (THA).

Methods

A retrospective analysis was conducted on the clinical data of 316 patients who underwent unilateral primary THA between September 2019 and August 2023. Among them, 117 patients underwent robot-assisted THA (group A), and 199 patients underwent conventional THA (group B). There was no significant difference between the two groups in the gender, age, or side of the hip replacement ( P>0.05); but there was a significant difference in the preoperative diagnosis ( P<0.05). The leg length discrepancy (LLD) and global offset (GO) dfference were measured on preoperative anteroposterior pelvic X-ray films, and absolute values were used for comparison between groups.

Results

The operations in both groups were successfully completed. Postoperative imaging measurements showed that the LLD and GO dfference in group A were significantly lower than those in group B ( P<0.05). Among them, group A had 32 cases (27.4%), 5 cases (4.3%), and 0 case (0) of LLD>3 mm, >5 mm, and >10 mm, respectively, while group B had 115 cases (57.8%), 75 cases (37.7%), and 22 cases (11.1%), respectively; and the differences in above indicators between groups were significant ( P<0.05). Group A had 40 cases (34.2%), 3 cases (2.6%), and 0 case (0) of GO dfference>5 mm, >10 mm, and >20 mm, respectively; group B had 103 cases (51.8%), 54 cases (27.1%), and 7 cases (3.5%), respectively. There was no significant difference in the proportion of patients with GO>20 mm between groups ( P>0.05), while there were significant differences in other indicators between groups ( P<0.05).

Conclusion

Compared with traditional THA, robot assisted THA has more advantages in restoration of limb length and offset distance.

Robotic-assisted total hip arthroplasty outperforms manual technique in obese and overweight patients: a prospective comparative study

BACKGROUND

With the increasing prevalence of obesity, there is growing awareness of the impact of overweight and obesity on total hip arthroplasty (THA). Research exploring the accuracy of acetabular component orientation in THA between robotic-assisted and manual techniques across different BMI categories is insufficient.

METHODS

This prospective study evaluated 221 patients who underwent THA with a Robotic Interactive Orthopaedic Arm system and 252 patients who underwent manual THA between March 2022 and January 2024. The patients were divided into four groups according to their BMI. We analysed whether there were differences in the accuracy of acetabular component positioning between robotic-assisted THA and manual THA across different BMI categories.

RESULTS

In the overweight group, robotic-assisted THA achieved a significantly higher rate of abductions within the target range (73/6) than manual THA (62/28) (p = 0.000). Both abductions and anteversions within the target range were also significantly more frequent in the robotic-assisted THA group (69/10) than in the manual THA group (56/34) (p = 0.000). Among the obese patients, robotic-assisted THA showed a perfect record for anteversions within the target range (29/0), markedly outperforming manual THA (39/6) (p = 0.040).

CONCLUSION

In the overweight (24 kg/m² ≤ BMI < 28 kg/m²) and obese (BMI ≥ 28 kg/m²) groups, robotic-assisted THA demonstrates significantly greater accuracy in acetabular component positioning compared to manual THA. This indicates that robotic-assisted technology may provide a more precise positioning of the acetabular component in overweight and obese patients.

Next generation legged robot locomotion: A review on control techniques

The next generation of autonomous-legged robots will herald a new era in the fields of manufacturing, healthcare, terrain exploration, and surveillance. We can expect significant progress in a number of industries, including inspection, search and rescue, elderly care, workplace safety, and nuclear decommissioning. Advanced legged robots are built with a state-of-the-art architecture that makes use of stereo vision and inertial measurement data to navigate unfamiliar and challenging terrains. However, designing controllers for these robots is a difficult task due to a number of factors, including dynamic terrains, tracking delays, inaccurate 3D maps, unforeseen events, and sensor calibration issues. To address these challenges, this paper discusses the current methods for controlling autonomous-legged robots. Our primary contribution is comparative research on robot control strategies such as virtual model control (VMC), model predictive control (MPC), and model-free reinforcement learning (RL). This paper provides information on different strategies for controlling autonomous legged robots and discusses the potential advancements and applications of this technology in the future. The aim of this study is to assist future researchers in making informed decisions on the selection of optimal control strategies and innovative concepts when developing and working with legged robots.

Patient-reported outcome differences for navigated and robot-assisted total hip arthroplasty frequently do not achieve clinically important differences: a systematic review

INTRODUCTION

Total hip arthroplasty (THA) using computer-assisted navigation (N-THA) and robot-assisted surgery (RA-THA) has been increasingly adopted to improve implant positioning and offset/leg-length restoration. Whether clinically meaningful differences in patient-reported outcomes (PROMs) compared to conventional THA (C-THA) are achieved with intraoperative technology has not been established. This systematic review aimed to assess whether published relative PROM improvements with technology use in THA achieved minimal clinically important differences (MCIDs).

METHODS

PubMed/MEDLINE/Cochrane Library were systematically reviewed for studies comparing PROMs for primary N-THA or RA-THA with C-THA as the control group. Relative improvement differences between groups were compared to established MCID values. Reported clinical and radiographic differences were assessed. Review of N-THA and RA-THA literature yielded 6 (n = 2580) and 10 (n = 2786) studies, respectively, for analyses.

RESULTS

Statistically significant improvements in postoperative PROM scores were reported in 2/6 (33.3%) studies comparing N-THA with C-THA, though only 1 (16.7%) reported clinically significant relative improvements. Statistically significant improvements in postoperative PROMs were reported in 6/10 (60.0%) studies comparing RA-THA and C-THA, though none reported clinically significant relative improvements. Improved radiographic outcomes for N-THA and RA-THA were reported in 83.3% and 70.0% of studies, respectively. Only 1 study reported a significant improvement in revision rates with RA-THA as compared to C-THA.

CONCLUSIONS

Reported PROM scores in studies comparing N-THA or RA-THA to C-THA often do not achieve clinically significant relative improvements. Future studies reporting PROMs should be interpreted in the context of validated MCID values to accurately establish the clinical impact of intraoperative technology.

Robotic Arm-Assisted System Improved Accuracy of Cup Position and Orientation in Cementless Total Hip Arthroplasty for Dysplastic Hips: A Comparison Among Groups With Manual Placement, Computed Tomography-Based Navigation, and Robotic Surgery

Background

Accurate cup placement in total hip arthroplasty (THA) for patients with dysplasia is challenging due to the distinctive bone deformities. This study aimed to compare the accuracy of cup placement position and orientation across robotic arm-assisted systems (R-THA), computed tomography-based navigation (N-THA), and manual procedure (M-THA) in THA for osteoarthritis secondary to dysplasia.

Methods

A total of 167 patients (197 hips), including 88 R-THAs, 45 N-THAs, and 46 M-THAs, were analyzed. Propensity score matching was performed to align the patient backgrounds. Horizontal and vertical centers of rotation were measured for cup position, whereas radiographic inclination and anteversion were measured for cup orientation. The proportion of cases with cup placement within 3 mm and 5° from the target was compared.

Results

R-THA had a significantly higher percentage of cup placement within 3 mm of the target compared to N-THA (78% vs 49%; P = .0041) and M-THA (78% vs 53%; P = .013). Similarly, R-THA was significantly more successful in placing the cup within 5° of the target compared to N-THA (84% vs 58%; P = .0049) and M-THA (91% vs 20%; P < .0001). Moreover, N-THA was significantly better at placing the cup within 5° of the target compared to M-THA (62% vs 14%; P < .0001), whereas there was no significant difference in the percentage of cup placement within 3 mm of the target (51% vs 51%; P = 1.0).

Conclusions

Robotic arm-assisted system and computed tomography-based navigation improved accuracy in cup orientation compared to the manual procedure. Additionally, the robotic arm-assisted system further improved cup position accuracy.

Robotic-assisted total hip arthroplasty in patients with developmental dysplasia of the hip

PURPOSES

Due to the morphological diversity of deformities, technical difficulties, improperly designed components, and so on, THA remains a challenging task in dysplastic hips, especially in highly dislocated hips. The purpose of this study was to comprehensively evaluate the clinical outcomes of robot-assisted THA in patients with DDH through a large cohort study, including the precision of acetabular cup positioning, indicators of inflammatory response, indicators of muscle damage, and complications.

METHODS

We retrospectively analyzed patients with DDH who underwent THA in our prospectively constructed joint registry between August 2018 and August 2022. Finally, 147 manual THAs and 147 robotic-assisted THAs were included in the final analysis. Patient demographics, indicators of inflammation, indicators of muscle damage, operative time, Harris hip scores (HHS), and forgotten joint score (FJS) were recorded for analysis. The precision of the positioning of the acetabular component was assessed with plain radiographs.

RESULTS

In the Crowe II/III groups, the reconstructed center of rotation (COR) in the robotic-assisted group was closer to the anatomical COR with less variation than the manual group (absolute horizontal distances of COR 3.5 ± 2.8 vs. 5.4 ± 4.9 mm, p < 0.05; absolute vertical distances of COR 6.4 ± 4.1 vs. 11.7 ± 8.2 mm, p = 0.001). For all Crowe subtypes, the robotic-assisted THA significantly increased the proportion of acetabular cups located in the safety zone within 5° (all p < 0.05). Interleukin-6 and creatine kinase levels were slightly lower and significantly different in the robotic-assisted group at three days postoperatively (all p < 0.05).

CONCLUSIONS

Compared to the manual technique, the robot-assisted technique improved the precision and reproducibility of acetabular component positioning, particularly in DDH patients with Crowe types II/III. The robotic-assisted technique did not increase operative time, bleeding, complications, or revision rates, and had a slighter early inflammatory response and muscle damage.

The learning curve of a novel seven-axis robot-assisted total hip arthroplasty system: a randomized controlled trial

BACGROUND

The aim of this study was to assess the learning curve of a novel seven-axis robot-assisted total hip arthroplasty (RaTHA) system.

METHODS

A total of 59 patients who underwent unilateral total hip arthroplasty at our institution from June 2022 to September 2022 were prospectively included in the study. In this randomized controlled clinical trial, robot-assisted THA (RaTHA) and Conventional THA (CoTHA) were performed using cumulative sum (CUSUM) analysis to evaluate the learning curve of the RaTHA system. The demographic data, preopera1tive clinical data, duration of operation, postoperative Harris Hip Score (HHS), postoperative Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and duration of operation between the learning stage and the proficiency stage of the RaTHA group were compared between the two groups.

RESULTS

The average duration of operation of the RaTHA group was increased by 34.73 min compared with the CoTHA group (104.26 ± 19.33 vs. 69.53 ± 18.38 min, p < 0.01). The learning curve of the RaTHA system can be divided into learning stage and proficiency stage, and the former consists of the first 13 cases by CUSUM analysis. In the RaTHA group, the duration of operation decreased by 29.75 min in the proficiency stage compared to the learning stage (121.12 ± 12.84 vs.91.37 ± 12.92, p < 0.01).

CONCLUSIONS

This study demonstrated that the surgical team required a learning curve of 13 cases to become proficient using the RaTHA system. The duration of operation, total blood loss, and drainage gradually shortened (decreased) with the learning curve stage, and the differences were statistically significant.

TRIAL REGISTRATION

Number: ChiCTR2200061630, Date: 29/06/2022.

A new designed full process coverage robot-assisted total hip arthroplasty: a multicentre randomized clinical trial

OBJECTIVE

To compare the effect of a new complete robot-assisted total hip arthroplasty (RA-THA) with that of the manual total hip arthroplasty (MTHA) and to verify the accuracy and safety of the former.

METHODS

Overall, 148 patients were enroled from 3 March 2021 to 28 December 2021 in this study and classified into RA-THA ( n =74 patients) and MTHA ( n =74 patients) groups. The sex, age, operative side, BMI, diagnosis, other basic information, operative time, acetabular prosthesis anteversion and inclination, femoral prosthesis anteversion and angulation, femoral prosthesis filling rate, leg length discrepancy (LLD), Harris hip score, and visual analogue scale (VAS) score of the two groups were compared.

RESULTS

No significant differences were observed in the two groups regarding sex, age, operative side, BMI, diagnosis, Harris hip score, VAS score, acetabular inclination, acetabular prosthesis anteversion, femoral prosthesis anteversion, combined anteversion, and femoral prosthesis filling rate ( P >0.05). The operative time was significantly longer in the RA-THA group than in the MTHA group (106.71±25.22 min vs. 79.42±16.16 min; t=7.30, P <0.05). The femoral angulation (1.78°±0.64°) and LLD (2.87±1.55 mm) in the RA-THA group were significantly lesser than those in the MTHA group (2.22°±1.11° and 5.81±6.27 mm, respectively; t=-2.95 and t=-3.88, P <0.05).

CONCLUSION

The complete RA-THA has some advantages over the traditional procedure in restoring the lower limb length and controlling the femoral prosthesis angulation. Thus, this study verifies the accuracy and safety of the robot-assisted system.

Fluoroscopy-based robotic assistance for total hip arthroplasty improves acetabular cup placement accuracy for obese patients compared to the manual, fluoroscopic- assisted technique

BACKGROUND

Patient obesity is a risk factor for poor acetabular cup positioning in total hip arthroplasty (THA).

OBJECTIVE

To assess the impact of using a novel, fluoroscopy-based robotic THA system on acetabular cup placement in obese versus non-obese patients.

METHODS

A review of 105 consecutive manual unassisted (mTHA) (47 Obese/58 Non-obese) and 102 robotic-assisted (RA-THA) (50 Obese/52 Non-obese) primary, direct anterior approach THA procedures was conducted. All cases were performed by a single surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Obesity was defined as a Body Mass Index (BMI) ⩾ 30 kg/m2. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone.

RESULTS

Obese patients in the mTHA cohort had larger cup inclination angles on average compared to non-obese patients (44.82∘± 6.51 vs. 41.39∘± 6.75; p= 0.009). Obese mTHA patients were less likely to have cup placement within the Lewinnek zone compared to non-obese mTHA patients (0.48 vs. 0.67; p= 0.027). Obesity had no effect on the accuracy of RA-THA.

CONCLUSION

Obesity affects the placement of the acetabular component in manual THA. The novel, fluoroscopy-based robotic THA system in this study demonstrated accurate cup placement regardless of obesity status.

Acetabular cup positioning in primary routine total hip arthroplasty-a review of current concepts and technologies

INTRODUCTION

Total hip arthroplasty (THA) has revolutionized the treatment of hip joint arthritis. With the increased popularity and success of the procedure, research has focused on improving implant survival and reducing surgical complications. Optimal component orientation has been a constant focus with various philosophies proposed. Regardless of the philosophy, achieving an accurate acetabular position for each clinical scenario is crucial. In this paper, we review the recent developments in improving the accuracy and ideal positioning of the acetabular cup in routine primary THA.

METHODOLOGY

A review of the recent scientific literature for acetabular cup placement in primary THA was performed, with available evidence for safe zones, spinopelvic relationship, preoperative planning, patient-specific instrumentation, navigation THA and robotic THA.

CONCLUSION

Though the applicability of Lewinnek safe zones has been questioned with an improved understanding of spinopelvic relationships, its role remains in positioning the acetabular cup in a patient with normal spinopelvic alignment and mobility. Evaluation of spinopelvic relationships and accordingly adjusting acetabular anteversion and inclination can significantly reduce the incidence of dislocation in patients with a rigid spine. In using preoperative radiography, the acetabular inclination, anteversion and intraoperative pelvic position should be evaluated. With improving technology and the advent of artificial intelligence, superior and more accurate preoperative planning is possible. Patient-specific instrumentation, navigated and robotic THA have been reported to improve accuracy in acetabular cup positioning as decided preoperatively but any significant clinical advantage over conventional THA is yet to be elucidated.

The invasiveness of robot-assisted total hip replacement is similar to that of conventional surgery

Robot-assisted total hip arthroplasty (R-THA) is increasingly being performed throughout the world. The invasiveness of this operation is unknown. We retrospectively reviewed the cohort of consecutive osteonecrosis of the femoral head (ONFH) patients who received primary R-THA or manual THA (M-THA) from January 2020 to January 2022 in our institution. One experienced surgeon performed all procedures. We calculated the propensity score to match similar patients in different groups by multivariate logistic regression analysis for each patient. We included confounders consisting of age, sex, body mass index (BMI), and operation time. Preoperative serum markers and Harris hip scores (HHS), postoperative serum markers at first day and third day, complications rate, postoperative HHS and Forgotten Joint Score (FJS) at 6 months after surgery of different cohorts were compared. We analyzed 218 ONFH patients treated with THA (98 R-THA patients, and 120 M-THA patients). After propensity score matching, we generated cohorts of 95 patients in R-THA and M-THA groups. We found no significant difference in preoperative serum markers and HHS. In the R-THA cohort, the PLT count was significantly lower on the postoperative day 1 (192.36 ± 41.72 × 109/L Vs 210.47 ± 72.85 × 109/L, p < 0.05). The Hb level was significantly lower on the postoperative third day in the R-THA cohort (98.52 ± 12.99 g/L Vs 104.74 ± 13.15 g/L, p < 0.05). There was no significant difference in the other serum markers between the cohorts on postoperative day 1 and 3 (p > 0.05). The FJS was significantly higher in the R-THA than M-THA group (p = 0.01). There was no significant difference in the postoperative HHS or complication rate between the groups (p > 0.05). The R-THA is not associated with a serious invasiveness compared to M-THA. Patients who underwent R-THA had a better early function compared to those who underwent M-THA.

Precise acetabular positioning, discrepancy in leg length, and hip offset using a new seven-axis robot-assisted total hip arthroplasty system requires no learning curve: a retrospective study

Objective

The purpose of the present study was to determine the learning curve for a novel seven-axis robot-assisted total hip arthroplasty (RA-THA) system, and to explore whether it was able to provide greater accuracy in acetabular cup positioning, superior leg length discrepancy (LLD), and hip offset than conventional methods.

Methods

A total of 160 patients in which unilateral THA was performed in the second affiliated Hospital of Xi'an Jiaotong University from July 2021 to September 2022 were studied. The first 80 patients underwent robot-assisted THA, while conventional THA was performed on the subsequent 80 by the same team of experienced surgeons. The learning curve for the RA-THA system was evaluated using cumulative sum (CUSUM) analysis. The demographic data, preoperative clinical data, duration of surgery, postoperative Harris hip score (HHS) and postoperative radiographic data from patients that had conventional THA were compared.

Results

The 80 patients who underwent primary unilateral RA-THA comprised 42 males and 38 females and were followed up for 12 weeks. Using analysis by CUSUM, the learning curve of the RA-THA system could be divided into learning and proficiency phases, the former of which consisted of the first 17 cases. There was no significant difference between the learning and proficiency phases in terms of LLD, hip offset, or accuracy of acetabular prosthesis position in the RA-THA groups. The proportion of acetabular prostheses located in the Lewinnek safe zone was 90.5% in the proficiency group and 77.5% in the conventional group, respectively, a difference that was statistically significant (P < 0.05). The absolute error between target angle and postoperative measured angle of anteversion was statistically significant in the proficiency group and the conventional group((P < 0.05). Postoperative acetabular anteversion and LLD were 19.96 ± 5.68° and 6.00 (5.00) mm in the proficiency group, respectively, and 17.84 ± 6.81° and 8.09 (4.33) mm using conventional surgery, respectively (anteversion: P = 0.049; LLD: P < 0.001).

Conclusions

The surgical team required a learning curve of 17 cases using the RA-THA system to become proficient. There was no learning curve for other parameters, namely LLD, hip offset, or accuracy of acetabular prosthesis positioning. During the proficiency phase, the RA system was superior to conventional THA for control of leg length and accuracy of acetabular cup placement.