Robotics Versus Navigation Versus Conventional Total Hip Arthroplasty: Does the Use of Technology Yield Superior Outcomes?

No difference in clinical outcomes in robotic-assisted vs. computer-navigated total hip arthroplasty

BACKGROUND

Robotic-assisted (RA) and computer-navigated (CN) total hip arthroplasty (THA) are increasingly performed, but prior studies comparing the two techniques and their outcomes were limited. This study aimed to compare clinical outcomes and costs of receiving THA using RA and CN technology.

METHODS

We conducted a retrospective cohort study using a nationwide administrative database from January 1, 2010, to October 31, 2022. The study included patients undergoing THA either via RA (n = 4,473) or CN (n = 4,473) technology. Subjects were matched for age and pertinent comorbidities. Clinical outcomes evaluated included emergency department visits and readmissions within 90 days of surgery, lengths of stay, and implant-related complications within 90 days and 2 years of surgery. Costs were analyzed on the day of surgery and within a 90-day global period. Statistical analysis was performed using multivariate logistic regression analysis with a P < 0.01 considered statistically significant.

RESULTS

There were no significant differences between the RA and CN cohort in ED visits or readmission within 90 days of surgery or in lengths of stay. Similarly, no differences were found in any of the implant-related complications at 90 days or 2 years following surgery. Same-day mean reimbursement for RA-THA was higher than for CN-THA ($4,472.23 vs. $3,890.61; P < 0.01). 90-day reimbursement did not differ significantly.

CONCLUSION

We demonstrated that readmission, ED visits, lengths of stay, and short-term implant-related outcomes did not differ between RA and CN-THA cohorts. Further studies are needed to explore the long-term benefits and cost implications of RA-THA.

How Much Does a Computed Tomography-Based Mixed-Reality Navigation System Change Freehand Acetabular Component Position?

Background

This study evaluates how a computed tomography-based mixed-reality (MR) navigation system impacts acetabular component orientation compared to freehand positioning in total hip arthroplasty.

Methods

A series of 79 patients who underwent total hip arthroplasty utilizing a computed tomography-based MR navigation system were reviewed. The surgeon initially placed the acetabular cup freehand, attempting to achieve the preoperative plan, and this initial intraoperative orientation was recorded. The cup was then adjusted to the planned position. The difference between freehand and planned tilt-adjusted operative anteversion (OA) and inclination (OI) determined the navigation tool's impact.

Results

The mean preoperative planned OA was 30.1 ± 2.0 (range: 25, 35) degrees, and the mean freehand intraoperative OA was 30.2 ± 9.1 (range: 4, 57) degrees (P = .885), requiring a mean adjustment of 6.8 ± 5.1 (range: 0, 23) degrees. Freehand OA was corrected at least 5 degrees in 54.4% (43/79) of cases. The mean preoperative planned OI was 40.8 ± 0.6 (range: 39, 42) degrees, and the mean freehand intraoperative OI was 37.8 ± 6.6 (range: 18, 53) degrees (P < .001), requiring a mean adjustment of 5.7 ± 4.5 (range: 0, 22) degrees to achieve. Freehand OI was corrected at least 5 degrees in 43.0% (34/79) of cases.

Conclusions

Freehand acetabular component positioning in the lateral position is variable when attempting to execute patient-specific numerical cup orientation targets. Use of this navigation tool led the surgeon to correct more than 5 degrees in both OA and OI in roughly half of the hips.

The Impact of Previous Lumbar Spine Surgery on Primary Total Hip Arthroplasty: Minimum 2-Year Outcomes Controlling for Approach and Technology

BACKGROUND

Prior lumbar spine surgery (LSS) can limit spine mobility, potentially increasing hip motion requirements. This study aimed to assess the influence of LSS on primary total hip arthroplasty (THA).

METHODS

Retrospective analysis was conducted on patients who underwent THA with prior LSS. Included patients had completed patient-reported outcomes (PROs) and visual analog scale for pain questionnaires or had a documented revision surgery with a minimum 2-year follow-up. Patients were propensity matched to a benchmark control group of patients who did not have previous spine pathology in a 1:3 ratio, controlling for age at surgery, surgical approach, use of advanced technology, sex, and body mass index. The analysis included comparisons of hip arthroplasty thresholds and complications. Subanalyses based on the type of lumbar surgery and type of approach were also conducted.

RESULTS

There were 244 hips included in the study. The LSS group reported comparatively lower postoperative PRO scores. However, the LSS group experienced a similar magnitude of improvement. The LSS group met patient acceptable symptom state threshold for Forgotten Joint Score at a significantly lower rate. The LSS had a higher frequency of complications leading to revision THA with a relative risk of 24 and a relative risk of 20.8 for revision THA due to instability. Comparing patients by type of LSS, PROs, the percentage of patients reaching hip arthroplasty thresholds, and the revision THA rates were similar. There was no difference in complications considering the type of approach.

CONCLUSIONS

Patients who had prior LSS who underwent primary THA demonstrated equivalent improvements in PROs, but achieved lower overall postoperative scores and met hip arthroplasty thresholds at lower rates. Furthermore, patients undergoing primary THA with prior LSS had a higher risk of complications leading to revision surgery, including a 24-fold relative risk for complications leading to revision and a 20.8-fold relative risk of revision due to instability.

Evaluation of cup placement accuracy in computer assisted total hip arthroplasty

BACKGROUND

Total hip arthroplasty (THA) accuracy has improved significantly with various advances in computer-assisted equipment (CAE), including robotic systems, computed tomography (CT) navigation, and portable navigation. However, no studies have directly compared the accuracy of acetabular cup placement and its impact on patient-reported outcome measures (PROMs) across these three CAE systems. In this study, we aimed to evaluate cup placement accuracy and PROMs in THA using different CAE systems.

METHODS

This retrospective analysis included 196 patients (202 hip joints) who underwent THA with three CAE systems from May 2021 to August 2023. Patients were categorized into the robotic system (73 hips), CT navigation (83 hips), and portable navigation (46 hips). Postoperative CT scans measured cup placement angles-radiographic inclination (RI) and radiographic anteversion (RA) -and compared them with preoperative target angles. Anterior-posterior (AP) cup position differences were evaluated by measuring the distance between the acetabular and cup center in the axial view of the postoperative CT scans. PROMs were evaluated using the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) at 3 and 12 months.

RESULTS

Demographic characteristics, including age, sex, primary disease, and Body Mass Index, were similar across groups. The robotic system exhibited significantly smaller deviations in ΔRI and ΔRA compared to CT navigation and portable navigation. AP cup position differences were also smaller in the robotic system versus portable navigation; however, the difference between the robotic and CT navigation systems was not statistically significant. Despite the superior precision of cup placement in the robotic system, no significant differences in JHEQ scores were observed among the groups at 3 and 12 months.

CONCLUSION

Robotic systems demonstrated superior accuracy in cup placement. However, short-term PROMs did not significantly differ, suggesting that PROMs may not solely depend on accurate cup placement. Future research should investigate additional factors influencing PROMs.

Evaluating the Accuracy of a Computed Tomography-Based Mixed-Reality Navigation Tool for Acetabular Component Positioning in Total Hip Arthroplasty

BACKGROUND

Robotics and navigation systems have improved the accuracy and precision of acetabular component placement in total hip arthroplasty (THA). The purpose of this study was to determine if the intraoperative use of a novel mixed-reality (MR) navigation system resulted in accurate acetabular component placement with minimal outliers.

METHODS

A series of 79 patients who underwent THA performed by a single surgeon using a novel MR navigation system were retrospectively reviewed. The preoperative planned acetabular component operative inclination (OI) and tilt-adjusted operative anteversion (OA) were collected for each case. At the six-week follow-up, each patient underwent three-dimensional EOS imaging, which was used to measure the acetabular component placement via validated measuring software. Patients who had bilateral THAs or three-dimensional images that did not have critical bony landmarks visible for measurement were excluded from the study. Absolute error was calculated for both inclination and anteversion. Outliers were defined as any cup position that was outside a range of ± 10 degrees from the preoperatively planned target. A total of 39 patients met the inclusion criteria.

RESULTS

The mean planned OI for each patient was 40.8 (range, 40 to 41) degrees, and the mean measured postoperative OI was 40.4 (range, 37 to 46) degrees (P = 0.40), resulting in a mean absolute error of 1.8 (range, zero to five) degrees. The mean planned OA was 30.2 (range, 25 to 35) degrees, and the mean measured postoperative OA was 31.1 (range, 27 to 42) degrees (P = 0.11), resulting in a mean absolute error of 2.0 (range, zero to six) degrees. There were no outliers in either OI or OA.

CONCLUSIONS

The results of this study suggest that the use of MR navigation during THA results in accurate postoperative acetabular component inclination and anteversion relative to the preoperative plan without outliers.

The Role of Artificial Intelligence and Emerging Technologies in Advancing Total Hip Arthroplasty

Total hip arthroplasty (THA) is a widely performed surgical procedure that has evolved significantly due to advancements in artificial intelligence (AI) and robotics. As demand for THA grows, reliable tools are essential to enhance diagnosis, preoperative planning, surgical precision, and postoperative rehabilitation. AI applications in orthopedic surgery offer innovative solutions, including automated hip osteoarthritis (OA) diagnosis, precise implant positioning, and personalized risk stratification, thereby improving patient outcomes. Deep learning models have transformed OA severity grading and implant identification by automating traditionally manual processes with high accuracy. Additionally, AI-powered systems optimize preoperative planning by predicting the hip joint center and identifying complications using multimodal data. Robotic-assisted THA enhances surgical precision with real-time feedback, reducing complications such as dislocations and leg length discrepancies while accelerating recovery. Despite these advancements, barriers such as cost, accessibility, and the steep learning curve for surgeons hinder widespread adoption. Postoperative rehabilitation benefits from technologies like virtual and augmented reality and telemedicine, which enhance patient engagement and adherence. However, limitations, particularly among elderly populations with lower adaptability to technology, underscore the need for user-friendly platforms. To ensure comprehensiveness, a structured literature search was conducted using PubMed, Scopus, and Web of Science. Keywords included "artificial intelligence", "machine learning", "robotics", and "total hip arthroplasty". Inclusion criteria emphasized peer-reviewed studies published in English within the last decade focusing on technological advancements and clinical outcomes. This review evaluates AI and robotics' role in THA, highlighting opportunities and challenges and emphasizing further research and real-world validation to integrate these technologies into clinical practice effectively.

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.

Perceptions and attitudes regarding robotic total hip arthroplasty: a patient stakeholder survey

To describe the attitudes and preferences of patients pertaining to robotic-assisted total hip arthroplasty (RA-THA) with the long-term objective of designing a prospective randomized-controlled trial (RCT) to evaluate the efficacy of RA-THA compared to conventional technique. A cross-sectional survey of patients attending an outpatient high-volume academic arthroplasty clinic chosen was administered from December 2023 to May 2024. The survey comprised 31 items including patient demographic, patient reported factors of significance and perceptions surrounding RA-THA. Ninety-seven patients completed the survey with a mean age of 67.5 ± 9.1 years and with 63% of patients being female. The majority of respondents were not at all familiar with RA-THA (69%). Common perceptions of RA-THA compared to conventional technique included a smaller incision (41%), lower chance of developing infection (47%), shorter length of surgery (41%), less blood loss (41%), lower cost (22%), shorter length of stay (30%), more precise implant positioning (46.8%), lower post-operative pain (29%), and lower post-operative complications (36%). Very important outcomes to be assessed in future investigations included post-operative range of motion (91%), implant longevity (91%), dislocation risk (90%), post-operative pain (89%), and infection risk (87%). Patient familiarity with robotic-assisted total hip arthroplasty is low. Patient perceptions regarding RA-THA compared to conventional technique are favorable, despite limited evidence to date. Important factors to be assessed in future RCTs include range of motion, implant longevity, dislocation risk, and infection risk. Findings of this study can inform a clinically relevant RCT assessing RA-THA compared to conventional technique.

Early Patient-Reported Outcome Measures Following Computer Navigated Total Hip Arthroplasty: A Study From the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

Total hip arthroplasty (THA) is a well-established treatment for symptomatic hip osteoarthritis (OA). The use of computer navigation in THA aims to achieve the reconstruction of the joint more consistently and precisely. The aim of this study was to contrast patient-reported outcome measures (PROMs) for THA procedures with and without commercially available navigation technologies.

METHODS

Postoperative PROMs for primary THA procedures performed for OA between August 2018 and December 2022 and recorded in the Australian Orthopaedic Association National Joint Replacement Registry were analyzed. Procedures using computer navigation were compared to those using conventional instrumentation. Baseline patient characteristics and surgeon volume were subanalyzed. Multivariable regressions were used to compare postoperative PROMs.

RESULTS

There were 13,400 THA procedures for OA with PROMs recorded and 749 with navigation. The mean (SD) EuroQol-visual analog scales (EQ-VASs) scores for navigated cases were 67.3 (19.3) preoperatively and 81.7 (15.0) postoperatively, compared with 66.0 (20.3) and 80.5 (15.8) for the non-navigated group. Oxford Hip scores and patient-reported change were similar between groups. The change from preoperative to postoperative EQ-VAS and Oxford Hip score did not significantly differ between computer-navigated and non-navigated cases. After adjusting for patient and procedure factors, the use of computer navigation was associated with a higher rate of procedure satisfaction (rate ratio 1.03, 95% confidence interval 1.01 to 1.06, P = 0.02).

CONCLUSIONS

While procedural satisfaction was marginally higher following navigated THA (P = 0.02), there were no statistically significant differences in the change in EQ-VAS or when comparing navigated with "non-navigated" approaches for primary THAs. Based on the reviewed national registry data for PROMS, we were unable to demonstrate clinically relevant evidence to support claims of superiority of non-navigated or navigated primary THAs. Further work, including similar comparisons with long-term follow-up, will be of value in elucidating if a true clinically relevant difference exists.

Computer-Assisted Total Hip Arthroplasty Improves Acetabular Prosthesis Placement Accuracy: A Multicenter, Randomized Controlled Clinical Study

OBJECTIVE

The long-term effectiveness of total hip arthroplasty (THA) largely depends on the accuracy of acetabular prosthesis placement. To improve the accuracy of acetabular prosthesis placement, we utilized a new surgical navigation system: visual treatment solution (VTS). The purpose of this study was to verify the efficacy and safety of this system in assisting THA.

METHODS

This was a prospective, multicenter, randomized controlled trial. One hundred and twenty-four patients undergoing primary THAs were included. The experimental group underwent VTS-assisted THA, and the control group underwent traditional surgical techniques. The main efficacy evaluation indicators were the proportion of anteversion and inclination angles in the Lewinnek safe zone, and secondary evaluation indicators included operation time, Western Ontario and McMaster University Osteoarthritis index (WOMAC) score, Harris score, short-form-36 (SF-36) score, and hip dislocation rate. Statistical analysis was performed mainly by t-test and chi-square test.

RESULTS

The proportion of both anteversion and inclination angles in the safe zone was 93.1% in the experimental group and 50.9% in the control group; the difference was significant (p < 0.01). The average operation time was 112.5 min in the experimental group and 92.6 min in the control group; the difference was significant (p < 0.01). There were no significant differences in WOMAC score, Harris score, or SF-36 score between the experimental and control groups at 3 months after the operation (p > 0.05). The dislocation rate was 0% in the experimental group and 1.6% in the control group; the difference was not significant (p > 0.05).

CONCLUSION

VTS-assisted THA can significantly improve the accuracy of acetabular prosthesis placement. However, there were no differences in short-term clinical outcomes or dislocation rates between the two groups.

Accuracy of robotic arm-assisted versus computed tomography-based navigation in total hip arthroplasty using the direct anterior approach: a retrospective study

BACKGROUND

A robotic arm-assisted and a computed tomography (CT)- based navigation system have been reported to improve the accuracy of component positioning in total hip arthroplasty (THA). However, no study has compared robotic arm-assisted THA (rTHA) to CT-based navigated THA (nTHA) concerning accuracy of cup placement and acetabular fractures using the direct anterior approach (DAA). This study aimed to compare the accuracy of cup placement and the presence of intraoperative acetabular fractures between rTHA and nTHA using DAA in the supine position.

METHODS

We retrospectively investigated 209 hips of 188 patients who underwent rTHA or nTHA using DAA (rTHA using the Mako system: 85 hips of 79 patients; nTHA: 124 hips of 109 patients). After propensity score matching for age and sex, each group consisted of 73 hips. We evaluated clinical and radiographic outcomes, comparing postoperative cup orientation and position, measured using a three-dimensional templating software, to preoperative CT planning. Additionally, we investigated the prevalence of occult acetabular fracture.

RESULTS

Clinical outcomes were not significantly different between the groups at 1 year postoperatively. The mean absolute error of cup orientation was significantly smaller in the rTHA group than in nTHA (inclination: 1.4° ± 1.2° vs. 2.7° ± 2.2°, respectively; p = 0.0001, anteversion: 1.5° ± 1.3° vs. 2.2° ± 1.7°, respectively; p = 0.007). The cases within an absolute error of 5 degrees in both RI and RA were significantly higher in the rTHA (97.3%) than in nTHA group (82.2%) (p = 0.003). The absolute error of the cup position was not significantly different between the two groups. The prevalence of occult acetabular fracture did not differ significantly between the two groups (rTHA: n = 0 [0%] vs. nTHA: n = 1 [1.4%]).

CONCLUSION

Cup placement using DAA in the supine position in rTHA was more accurate with fewer outliers compared to nTHA. Therefore, rTHA performed via DAA in a supine position would be useful for accurate cup placement.

Intraoperative Navigation in Reverse Shoulder Arthroplasty: Advantages and Future Prospects

Intraoperative navigation is a novel technology that can provide real-time feedback to the surgeon during implantation and enhance the accuracy and precision of glenoid component positioning. Applications of intraoperative navigation systems have demonstrated increased precision in baseplate version and inclination, as well as improved baseplate screw placement, with fewer screws used and greater purchase length achieved when compared to standard instrumentation. Early clinical studies have shown favorable results, with significantly improved patient-reported and clinical outcomes and decreased complications. The implementation of intraoperative navigation is associated with a short learning curve and a minimal increase in operative time. Nevertheless, further research is necessary to substantiate the clinical benefit of navigation and evaluate its economic cost-effectiveness and impact on implant survival. Augmented reality and robotic-assisted surgery are additional emerging technologies that, while novel, hold the potential to further advance the field of shoulder arthroplasty.

Fewer Dislocations After Total Hip Arthroplasty With Robotic Assistance or Fluoroscopic Guidance

BACKGROUND

Computer navigation and robotic assistance may reduce total hip arthroplasty (THA) dislocations by improving the accuracy and precision of component positioning. We investigated dislocation rates for THAs using conventional techniques, robotic assistance, and computer navigation, while controlling for surgical approach, dual mobility (DM) use, and fluoroscopic guidance.

METHODS

We reviewed 11,740 primary THAs performed between June 2016 and December 2022, including 5,873 conventional, 1,293 with robotic-arm assistance, and 4,574 with navigation. The approach was posterior in 6,580 (56.0%), anterior in 4,342 (37.0%), and lateral in 818 (7.0%). A DM was used in 10.4%. Fluoroscopy was used in 3,653 cases and only with the anterior approach. Multivariate analyses yielded odds ratios (OR) for dislocation and revision. Additional regression analyses for dislocation were performed for approach and DM.

RESULTS

Raw dislocation rates were as follows: conventional 1.2%, robotic 0.4%, navigation 0.9%, anterior with fluoroscopy 0.4%, anterior without fluoroscopy 2.3%, posterior 1.3%, and lateral 0.5%. Upon multivariate analysis, use of robotics was found to be associated with significantly reduced dislocation risk compared to conventional (OR: 0.3), as did anterior (OR: 0.6) compared to posterior approach; navigation and lateral approach were not found to be associated with a significant reduction in risk. For the anterior approach, multivariate analysis demonstrated that fluoroscopy significantly reduced dislocation risk (OR: 0.1), while DM, robotics, and navigation were not significant. For the posterior approach, the dislocation risk was lower with robotics than with conventional (OR: 0.2); the use of navigation or DM did not demonstrate a significant reduction in risk.

CONCLUSIONS

The use of robotics was associated with a reduction in dislocations for this cohort overall. Further, fluoroscopy in the anterior approach and robotic assistance in the posterior approach were both associated with decreased dislocation risk. The role of imageless computer navigation and DM implants requires further study.

Length of Stay and Discharge Disposition After Total Hip Arthroplasty: A Large Multicenter Propensity Matched Comparison of Robotic-Assisted and Manual Techniques

BACKGROUND

Robotic-arm assistance continues to gain popularity in total hip arthroplasty (THA) for its potential to improve component placement accuracy and patient outcomes. Nonetheless, there is limited data on the impact of robotic-assisted THA (RA-THA) on hospital length of stay (LOS) and discharge location. This study thus aimed to compare LOS, discharge location, and readmission rate for propensity-matched cohorts of RA-THA versus manual THA (M-THA).

METHODS

A retrospective review of a multi-hospital database was performed to identify patients who underwent THA between January 2016 and December 2021 from surgeons who performed both RA-THA and M-THA at 77 geographically diverse hospitals. The RA-THA and M-THA cohorts were 1-to-1 matched based on patient sex, age, and body mass index, resulting in 8,536 patients per cohort. Insurance type, LOS, same-day discharge, discharge disposition, and 90-day all-cause readmission rate were compared using Mann-Whitney U and Chi-square tests.

RESULTS

Average LOS was significantly shorter for RA-THA patients (1.39 ± 0.85 days) than for M-THA patients (1.48 ± 0.91 days, P < .001). Compared to 5.6% of M-THA patients, 5.3% of RA-THA patients underwent same-day discharge (P = .38). There were statistically significant differences in discharge disposition between cohorts, with more RA-THA cases discharged home without home healthcare compared to M-THA (47.9 versus 45.5%, P = .001) and fewer RA-THA cases discharged to a skilled nursing facility compared to M-THA (5.6 versus 6.9%, P = .001). The 90-day all-cause readmission rate for RA-THA cases was 3.0%, compared to 3.4% for M-THA cases (P = .26).

CONCLUSIONS

Compared to M-THA, RA-THA had a shorter average LOS, a similar percentage of patients with same-day discharge, fewer patients who had skilled nursing facility discharge, and a similar all-cause 90-day readmission rate. These results may be of interest to surgeons participating in bundled payment programs and engaging in cost savings.

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.

Impact of Offset and Leg Length on Functional Outcomes Post-Total Hip Arthroplasty: How Accurate Should Coronal Reconstruction Be?

BACKGROUND

Accurate hip reconstruction is associated with improved biomechanical behavior following total hip arthroplasty (THA). However, whether this is associated with improved patient-reported outcomes (PROs) is unknown.

HYPOTHESIS/PURPOSE

This study aimed to: 1) describe the ability to reconstruct coronal geometry during THA without advanced technology; 2) assess whether restoration of global offset (GO) and leg length (LL) is associated with improved PROs; and 3) investigate whether increased femoral offset (FO) to compensate for reduced acetabular offset (AO) influences PROs.

METHOD

This was a prospective, multicenter, consecutive cohort study of 500 patients treated with primary THA without robotics or navigation. The Oxford Hip score (OHS) was obtained preoperatively and at 1-year follow-up. Supine anteroposterior pelvic radiographs were analyzed to determine AO, FO, GO, and LL relative to the native contralateral side. Contour plots for ΔOHS based on ΔLL and ΔGO were created, and ΔOHS was calculated within and outside various ranges (±2.5, ±5, or ±10 mm).

RESULTS

In the operated hip, mean FO increased by 3 ± 6 mm (range, -16 to 27), while AO decreased by 2 ± 4 mm (range, -17 to 10). The contour graph for ±2.5 mm zones showed the best outcomes (ΔOHS >25) with GO and LL centered on 0 ± 2.5 mm (P < .01). However, only 10% achieved such reconstruction. When GO and LL differences were within ±10 mm, ΔOHS was superior when both AO and FO were within ±5 mm (mean: 24 ± 10; range, -5 to 40) compared with when FO was above 5 mm to compensate for a reduction in AO (mean: 22 ± 11; range, -10 to 46; P = .040).

CONCLUSIONS

The PROs were associated with biomechanical reconstruction, and the best clinical improvement can be expected when GO and LL differences are both within 2.5 mm. Maintenance of AO is important, as compensation by increasing FO is associated with inferior OHS.

Why robot-assisted total hip arthroplasty aborted: Chinese experience of four hundred and twenty nine consecutive cases

PURPOSE

Robot-assisted total hip arthroplasty (RA-THA) helps with precise orientation of the prosthesis, but some RA-THA procedures are aborted intraoperatively and are converted to manual total hip arthroplasty (THA). This study aimed to analyse why RA-THA is sometimes aborted intraoperatively and to make recommendations accordingly.

METHODS

A total of 429 consecutive Mako THA cases in our prospective database from August 2018 to June 2021 were included in our study. All robotic procedures aborted intraoperatively for any reason were recorded. The patients' demographics, diagnoses, and surgeons' information were included in the statistical analysis to pinpoint the risk factors for intraoperative robot to manual conversion.

RESULTS

Intraoperative RA-THA abortions occurred in 17 cases (3.96%) and the patients had to be converted to manual THA. The adverse events leading to intraoperative abortions included pelvic array loosening or malposition (5, 1.17%), inaccurate bone mapping or construction (6, 1.40%), inaccurate initial registration (4, 0.93%), and other reasons (2, 0.47%).

CONCLUSION

Robot-related adverse events could be found in all perioperative steps of RA-THA, and some of these events might result in intraoperative abortion. Complex hip disease was a statistically significant factor for an increased risk of intraoperative abortion of RA-THA. Standardized surgical procedures and preoperative assessments can be helpful in reducing the rate of RA-THA abortions.

Does Approach Matter in Robotic-Assisted Total Hip Arthroplasty? A Comparison of Early Reoperations Between Direct Anterior and Postero-Lateral Approach

BACKGROUND

There is no consensus on whether direct anterior approach (DAA) or postero-lateral approach (PLA) total hip arthroplasty (THA) confers a lower risk of postoperative complications. Robotic assistance in THA results in a more consistently accurate component position compared to manual THA. The objective of this study was to compare rates of dislocation, reoperation, revision, and patient-reported outcome measures between patients undergoing DAA and PLA robotic-assisted primary THA.

METHODS

We identified 2,040 consecutive robotic-assisted primary THAs performed for primary osteoarthritis, using DAA (n = 497) or PLA (n = 1,542) between 2017 and 2020. The mean follow-up was 18 months. Kaplan-Meier analysis estimated survivorship free of dislocation, reoperation, and revision. Achievement of patient acceptable symptom state and minimum clinically important difference were used to compare changes in the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR) and Visual Analog Scale.

RESULTS

Dislocation was rare in this series (14 in 2,040, 0.7%), including 1 of 497 (0.2%) in the DAA cohort and 13 of 1,542 (0.8%) in the PLA cohort (P = .210). There was no difference in 2-year reoperation-free survivorship (97.8 versus 98.6%, P = .59) or revision-free survivorship (98.8 versus 99.0%, P = .87) at any time point. After controlling for age, sex, and body mass index, there was no difference in dislocation, reoperation, or revision. At 6-week follow-up, after controlling for age, sex, and body mass index, patients in the DAA cohort had higher odds of achieving HOOS JR minimum clinically important difference (odds ratio = 2.01, P = .012) and HOOS JR patient acceptable symptom state (odds ratio = 1.72, P = .028). There were no differences in patient-reported outcome measures by 3 months.

CONCLUSIONS

For robotic-assisted primary THA, DAA may confer enhanced early (<6 weeks) functional recovery compared to the PLA, but there was no significant difference in postoperative dislocation, reoperation, or revision rates.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system resulted in greater improvements in hip-specific outcome measures at one-year compared to a CT-based robotic-assisted system

BACKGROUND

The purpose of this study was to compare one-year patient reported outcome measures between a novel fluoroscopy-based robotic-assisted (FL-RTHA) system and an existing computerised tomography-based robotic assisted (CT-RTHA) system.

METHODS

A review of 85 consecutive FL-RTHA and 125 consecutive CT-RTHA was conducted. Outcomes included one-year post-operative Veterans RAND-12 (VR-12) Physical (PCS)/Mental (MCS), Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function (PS)/Joint replacement, and University of California Los Angeles (UCLA) Activity scores.

RESULTS

The FL-RTHA cohort had lower pre-operative VR-12 PCS, HOOS Pain, HOOS-PS, HOOS-JR, and UCLA Activity scores compared with patients in the CT-RTHA cohort. The FL-RTHA cohort reported greater improvements in HOOS-PS scores (-41.54 vs. -36.55; p = 0.028) than the CT-RTHA cohort. Both cohorts experienced similar rates of major post-operative complications, and had similar radiographic outcomes.

CONCLUSIONS

Use of the fluoroscopy-based robotic system resulted in greater improvements in HOOS-PS in one-year relative to the CT-based robotic technique.

Robot-Assisted Total Hip Arthroplasty Demonstrates Improved 90-Day Clinical and Patient-Reported Outcomes

Background

The utilization of technology, including robotics and computer navigation, in total hip arthroplasty (THA) has been steadily increasing; however, conflicting data exists regarding its effect on short-term clinical and patient-reported outcomes. Therefore, this study sought to explore the association between different surgical technologies and postoperative outcomes following THA.

Methods

We retrospectively reviewed 9892 primary THA cases performed by 62 surgeons from a single institution from September 2017 to November 2022. Three cohorts were created based on the utilization of technology: conventional (no technology), navigation, or robotics. Patient demographics, clinical outcomes, and patient-reported outcome measures were collected over the first 90 days following surgery. This data was compared using analysis of variance and multivariate logistic regressions. In total, 4275 conventional, 4510 navigation, and 1107 robotic cases were included in our analyses.

Results

The robotic cohort achieved a perfect Activity Measure for Post-Acute Care (AM-PAC) score earliest (0.1 days, P < .001). After adjusting for potential confounding variables, use of robotic assistance was associated with greater odds of achieving a perfect AM-PAC score on postoperative day 0 (odds ratio 1.6, P < .001) and greater odds of having length of stay shorter than 24 hours (odds ratio 2.3, P < .001) compared to no technology use in THA. Hip dysfunction and Osteoarthritis Outcome Score, Joint Replacement and Patient-Reported Outcomes Measurement Information System Pain Interference scores showed the greatest improvement in the robotic cohort at both 6 weeks and 3 months following surgery.

Conclusions

The present study demonstrates favorable clinical and patient-reported outcomes in the first 90 days following surgery for patients undergoing robot-assisted THA compared to conventional and navigation-assisted THA.

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.

Robotics and Navigation Do Not Affect the Risk of Periprosthetic Joint Infection Following Primary Total Hip Arthroplasty: A Propensity Score-Matched Cohort Analysis

BACKGROUND

The use of computer navigation or robotic assistance during primary total hip arthroplasty (THA) has yielded numerous benefits due to more accurate component positioning. The utilization of these tools is generally associated with longer operative times and also necessitates additional surgical equipment and personnel in the operating room. Thus, the aim of this study was to evaluate the impact of technology assistance on periprosthetic joint infection (PJI) after primary THA.

METHODS

We retrospectively reviewed the records for 12,726 patients who had undergone primary THA at a single high-volume institution between 2018 and 2021. Patients were stratified by surgical technique (conventional THA, computer-navigated THA [CN-THA], or robotic-assisted THA [RA-THA]) and were matched 1:1 with use of propensity score matching. Univariate and logistic regression analyses were performed to compare the rates of PJI within 90 days postoperatively between the cohorts.

RESULTS

After propensity score matching, there were 4,006 patients in the THA versus RA-THA analysis (2,003 in each group) and 5,288 patients in the THA versus CN-THA analysis (2,644 in each group). CN-THA (p < 0.001) and RA-THA (p < 0.001) were associated with longer operative times compared with conventional THA by 3 and 11 minutes, respectively. The rates of PJI after conventional THA (0.2% to 0.4%) were similar to those after CN-THA (0.4%) and RA-THA (0.4%). On the basis of logistic regression, the development of PJI was not associated with the use of computer navigation (odds ratio [OR], 1.8 [95% confidence interval (CI), 0.7 to 5.3]; p = 0.232) or robotic assistance (OR, 0.9 [95% CI, 0.3 to 2.3]; p = 0.808).

CONCLUSIONS

Despite longer operative times associated with the use of computer navigation and robotic assistance, the use of these tools was not associated with an increased risk of PJI within 90 days after surgery.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Mixed Reality Navigation in Hip Fusion Conversion: A Novel Utilization of Advanced Technology: A Case Report

CASE

A 32-year-old woman with a history of hip fusion presented with significant lower back, hip, and knee pain as well as severely limited hip mobility and function. Single-stage fusion takedown and conversion to total hip arthroplasty (THA) was performed using augmented reality navigation. At 1 year, the patient was pain free with improved function. This study is the first to report the technique and outcomes of surgical fusion conversion to THA, using mixed reality navigation.

CONCLUSION

Mixed reality navigation in complex conversion THA can be useful for identifying the patient's true acetabulum and for patient-specific acetabular component placement to maximize outcomes.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system produced greater improvements in patient-reported outcomes at one year compared to manual, fluoroscopic-assisted technique

INTRODUCTION

The adoption of new technology should be supported by improvements in patient-reported outcomes (PROMs). The purpose of this study was to assess the one-year PROMs of patients who underwent total hip arthroplasty (THA) using a novel, fluoroscopy-based, robotic-assisted (RA-THA) system when compared to a manual, fluoroscopic-assisted technique (mTHA).

MATERIALS AND METHODS

A review of 91 consecutive mTHA and 85 consecutive RA-THA via a direct anterior approach was conducted. All cases were performed by the same surgeon at the same institution, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included one-year Veterans RAND-12 (VR-12) Physical/Mental, Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function/Joint Replacement, and University of California Los Angeles (UCLA) Activity scores, as well as the difference between pre-operative and one-year post-operative PROMs.

RESULTS

Patients in the RA-THA cohort had lower pre-operative HOOS-JR scores compared to patients in the mTHA cohort (37.0 vs. 43.1; p = 0.031). Cohorts experienced similar one-year post-operative VR-12, HOOS, and UCLA Activity scores. Patients in the RA-THA cohort experienced greater improvements across all pre- and post-operative HOOS scores compared to patients in the mTHA cohort: Pain (+ 54.7 vs. +42.1; p = 0.009), Physical Function (-41.6 vs. -28.7; p = 0.007), and Joint Replacement (+ 46.6 vs. +33.0; p = 0.002). These differences exceeded minimum clinically important difference (MCID).

CONCLUSIONS

Both manual and robotic cohorts experienced benefit from THA at one-year post-operative. Importantly, the use of a novel, fluoroscopy-based robotic assistance system for primary THA resulted in greater improvements in PROMs at one-year relative to manual technique.

Lower Intraoperative and Immediate Postoperative Complications in Robotic Versus Conventional Primary Total Hip Arthroplasty: A Retrospective Cohort Analysis of Over 360,000 Patients

PURPOSE

Although a trend of an improved alignment with robotic total hip arthroplasty (THA) over conventional methods has surfaced from recent series, it is unknown whether these results translate into meaningful enhancements in postoperative outcomes. To address this lack in the literature, we compared the perioperative morbidity and mortality with robotic and conventional THA in a large national cohort of 367,894 patients. We hypothesized that no significant differences would exist in the outcomes between the two groups.

METHODS

Records were extracted from 2016-2019 from the National Inpatient Sample (NIS) database Healthcare Cost and Utilization Project which is the largest in-patient database in the United States. From 367,894 THAs, robotics were employed for 7,863 patients. The remaining 360,031 conventional THAs served as controls. The two groups were compared for demographics, admission, and hospital stay details including costs, and mortality and morbidity data including medical and surgical complications. Descriptive statistics were used for demographic data while analytical statistics including t-tests, chi-squared tests, Fischer exact test, and Pearson chi-squared tests were used for perioperative outcomes. Statistical significance was set at p<0.005.

RESULTS

Demographic distributions between robotic and conventional THA groups displayed similar age and sex characteristics. Shorter mean lengths of stay (1.87 days) were seen in robotic THA versus conventional THA (2.33 days) while higher costs were noted for the former (mean $68,686.71 vs $66,840.39) (p<0.005). Low overall mortality (0.03% robotic, 0.09% conventional) was seen in both groups (p>0.005). Higher comparative incidences of anemia, acute renal failure, and pneumonia were seen in conventional THA (p<0.005) while no significant differences were noted for other complications including myocardial infarction, pulmonary embolism, deep vein thrombosis, and cardiac arrest (p>0.005). Among others, lower dislocation rates, mechanical complications, periprosthetic joint infection, and periprosthetic fractures were seen with robotic THA (p<0.005). Wound complications and superficial infection rates did not differ between the two groups (p>0.005).

CONCLUSIONS

Evidence has emerged from our results to support more routine adaptation of the robotic option of performing a THA. These can be based on lower local, systemic, and mechanical complications as demonstrated by the present study. Further evaluation of these results in follow-up would help establish the foothold of robotic surgery in total hip replacement in the modern context.

THA-Net: A Deep Learning Solution for Next-Generation Templating and Patient-specific Surgical Execution

BACKGROUND

This study introduces THA-Net, a deep learning inpainting algorithm for simulating postoperative total hip arthroplasty (THA) radiographs from a single preoperative pelvis radiograph input, while being able to generate predictions either unconditionally (algorithm chooses implants) or conditionally (surgeon chooses implants).

METHODS

The THA-Net is a deep learning algorithm which receives an input preoperative radiograph and subsequently replaces the target hip joint with THA implants to generate a synthetic yet realistic postoperative radiograph. We trained THA-Net on 356,305 pairs of radiographs from 14,357 patients from a single institution's total joint registry and evaluated the validity (quality of surgical execution) and realism (ability to differentiate real and synthetic radiographs) of its outputs against both human-based and software-based criteria.

RESULTS

The surgical validity of synthetic postoperative radiographs was significantly higher than their real counterparts (mean difference: 0.8 to 1.1 points on 10-point Likert scale, P < .001), but they were not able to be differentiated in terms of realism in blinded expert review. Synthetic images showed excellent validity and realism when analyzed with already validated deep learning models.

CONCLUSION

We developed a THA next-generation templating tool that can generate synthetic radiographs graded higher on ultimate surgical execution than real radiographs from training data. Further refinement of this tool may potentiate patient-specific surgical planning and enable technologies such as robotics, navigation, and augmented reality (an online demo of THA-Net is available at: https://demo.osail.ai/tha_net).

Improved radiographic outcomes and decreased complications rate on the femoral side can be achieved by a novel designed whole-process robotic assisted hip system for total hip arthroplasty: a prospective randomized controlled trial

Postoperative complications due to inaccurate prosthesis positioning are the main causes of early revision. The aim of this study was to (1) determine whether novel designed whole-process robotic assisted hip system allowed better radiographic outcomes and lower complications risk on the femoral side particularly stem subsidence compared to conventional THA, and to (2) identify the comparison of early clinical outcomes. 72 patients were initially enrolled and randomly divided into 2 groups. Finally, only 65 patients (31 RA-THAs, 34 C-THAs) were analyzed who had full 18-month follow-up data. Radiographic follow-up was performed at immediate and 6-month postoperatively, while clinical follow-up at 18-month postoperatively. Stem-related radiographic outcomes, femoral side complications and clinical scores were compared. The robotic arm allowed better radiographic outcomes of the femoral side, including a higher canal fill ratio (CFR) at B1 (P = 0.040), more neutral stem alignment (P = 0.029), lower subsidence (P = 0.023) and lower leg length discrepancy (LLD) (P = 0.010). In addition, low CFR at B1 (P = 0.001) was found the risk factor for subsidence. However, early clinical outcomes were consistent between both groups. The novel designed whole-process robotic assisted hip system covers both femoral and acetabular side operations. It allows accurate and safe manipulation of femoral side, including better stem-related radiographic outcomes and lower risk of subsidence and LLD. However, no advantage of robotic system in early clinical score was identified. Clinical trial registration number: ChiCTR2100044124.

Patient Perception of Robotic-Assisted Total Joint Arthroplasty in a Hispanic Population

Background

Robotic-assisted orthopaedic surgery has become popular and widely available, mainly for total joint arthroplasty. However, there has been a persistent concern regarding access to robotic-assisted surgery and the utilization rate of total joint arthroplasty among minority groups. As an imperative effort to close the gap regarding health inequalities, we assessed the knowledge and perspective of Hispanics regarding robotic-assisted orthopaedic surgery.

Methods

A 28-item questionnaire was established to evaluate Hispanics' perceptions of robotic-assisted orthopaedic surgery. Participants answered questions about demographic features, knowledge about robotic-assisted orthopaedic surgery, and preferences regarding manual vs robotic-assisted procedures.

Results

A total of 580 questionnaires were analyzed in our study, with an average age of participants of 49.1 years. Only 44.2% of the participants were familiar with robotic-assisted orthopaedic surgery. Fifty-three percent of the respondents preferred robotic-assisted surgery over conventional procedures, with many participants believing that robotic-assisted surgery leads to better outcomes (54.7%) and faster recovery (53.1%).

Conclusions

Knowledge about specific factors such as clinical outcomes and costs may influence the perception and preference of Hispanics toward robotic-assisted orthopaedic surgery. Therefore, patient education may play a crucial role in the informed decision-making process in Hispanics when opting between robotic-assisted or traditional orthopaedic surgery.

Imageless navigation system (Naviswiss) provides accurate component position in total hip arthroplasty with lateral decubitus position for end-stage hip osteoarthritis: a prospective cohort study with CT-validation

AIMS

The Naviswiss system (Naviswiss AG, Brugg, Switzerland) is a handheld imageless navigation device used to improve the accuracy of implant positioning in total hip arthroplasty (THA). However, clinical data for leg length discrepancy and femoral offset is lacking, and the validity of the system has not been reported for patients undergoing THA in the lateral decubitus position. This study aimed to report the accuracy of the device in this patient population.

METHODS

Patients underwent THA in the lateral decubitus position performed by a single surgeon. Component position measured by the device intraoperatively was compared to postoperative measurements on computed tomography (CT) scans. Agreement between the navigation system and postoperative measurements was reported for acetabular cup inclination, acetabular cup version, femoral offset, and leg length discrepancy.

RESULTS

Thirty-three patients were included in the analysis. The mean difference between intraoperative and postoperative CT measurements was within 2° for angular measurements and 2 mm for leg length. Absolute differences in the two indices were up to 4° and 3 mm. The mean bias was 1°-2° overestimation for cup orientation and up to 2 mm overestimation for leg length change. However, 95% limits of agreement did not exceed absolute thresholds of 10° and 10 mm, especially after correction for bias. One case (3%) was declared intraoperatively for issues with fixation on the greater trochanter.

CONCLUSIONS

The accuracy of the Naviswiss system falls within clinically acceptable recommendations for acetabular cup placement, femoral offset, and leg length for total hip arthroplasty with a anterolateral approach in lateral decubitus position. The system could be further improved with regression-based bias correction.

Lower 90-day inpatient readmission and 1-year reoperation in patients undergoing robotic versus manual total hip arthroplasty through an anterior approach

BACKGROUND

The value of robotic-assisted total hip arthroplasty (rTHA) has yet to be determined compared to conventional manual THA (mTHA).

OBJECTIVE

Evaluate 90-day inpatient readmission rates, rates of reoperation, and clinically significant improvement of patient-reported outcome measures (PROMs) at 1-year in a cohort of patients who underwent mTHA or rTHA through a direct anterior (DA) approach.

METHODS

A single-surgeon, prospective institutional cohort of 362 patients who underwent primary THA for osteoarthritis via the DA approach between February 2019 and November 2020 were included. Patient demographics, surgical time, discharge disposition, length of stay, acetabular cup size, 90-day inpatient readmission, 1-year reoperation, and 1-year PROMs were collected for 148 manual and 214 robotic THAs, respectively.

RESULTS

Patients undergoing rTHA had lower 90-day readmission (3.74% vs 9.46%, p= 0.04) and lower 1-year reoperation (0.93% vs 4.73% mTHA, p= 0.04). rTHA acetabular cup sizes were smaller (rTHA median 52, interquartile range [IQR] 50; 54, mTHA median 54, IQR 52; 58, p< 0.001). Surgical time was longer for rTHA (114 minutes vs 101 minutes, p< 0.001). At 1-year post-operatively, there was no difference in any of the PROMs evaluated.

CONCLUSION

Robotic THA demonstrated lower 90-day readmissions and 1-year reoperation rates than manual THA via the DA approach. PROMs were not significantly different between the two groups at one year.

CT validation of intraoperative imageless navigation (Naviswiss) for component positioning accuracy in primary total hip arthroplasty in supine patient position: a prospective observational cohort study in a single-surgeon practice

BACKGROUND

The aim of this study was to report on the validity of the Naviswiss handheld image-free navigation device for accurate intraoperative measurement of THA component positioning, in comparison with the three-dimensional (3D) reconstruction of computed tomography (CT) images as the gold standard.

METHODS

A series of patients presenting to a single-surgeon clinic with end-stage hip osteoarthritis received primary hip arthroplasty with the anterolateral muscle-sparing surgical approach in the supine position. Imageless navigation was applied during the procedure with bone-mounted trackers applied to the greater trochanter and ASIS. Patients underwent routine CT scans before and after surgery and these were analyzed by using three-dimensional reconstruction to generate cup orientation, offset and leg length changes, which were compared to the intraoperative measurements provided by the navigation system. Estimates of agreement between the intraoperative and image-derived measurements were assessed with and without correction for bias and declared cases with potential measurement issues.

RESULTS

The mean difference between intraoperative and postoperative CT measurements was within 2° for angular measurements and 2 mm for leg length. Absolute differences for the two indices were between 5° and 4 mm. Mean bias was 1.9°-3.6° underestimation for cup orientation and up to 2 mm overestimation for leg length change, but absolute thresholds of 10° and 10 mm were not exceeded by 95% limits of agreement (LOA), especially after correction for bias. Four cases (12%) were declared intraoperatively for issues with fixation on the greater trochanter. Inclusion of these cases generated acceptable accuracy overall and their omission failed to improve between-case variability in accuracy or LOA for both offset and leg length.

CONCLUSIONS

The accuracy of the Naviswiss system applied during primary THA in a supine position and anterolateral surgical approach falls within clinically acceptable recommendations for acetabular cup placement, femoral offset, and length. With refinements to surgical technique to adapt to the navigation hardware, the system could be further improved with regression-based bias correction.

TRIAL REGISTRATION

Registered with the Australian New Zealand Clinical Trials Registry (ACTRN12618000317291).

Augmented reality-assisted versus conventional total hip arthroplasty: a systematic review and meta-analysis

BACKGROUND

Extended reality (XR), including virtual reality, augmented reality (AR), and mixed reality, has been used to help achieve accurate acetabular cup placement in total hip arthroplasty (THA). This study aimed to compare the differences between XR-assisted and conventional THA.

METHODS

In this systematic review and meta-analysis, electronic databases including PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and clinicaltrials.gov were searched for studies from inception to September 10, 2023. The outcomes were accuracy of inclination and anteversion, duration of surgery, and intraoperative blood loss. Meta-analysis was performed using Review Manager 5.4 software.

RESULTS

A total of five studies with 396 patients were included in our study. The pooled results indicated AR-assisted THA had better accuracy of inclination and anteversion than conventional THA (SMD = - 0.51, 95% CI [- 0.96 to - 0.07], P = 0.02; SMD = - 0.96, 95% CI [- 1.19 to - 0.72], P < 0.00001), but duration of surgery and intraoperative blood loss were similar in the two groups.

CONCLUSION

This systematic review and meta-analysis found that AR-assisted THA had better accuracy of inclination and anteversion than conventional THA, but the duration of surgery and intraoperative blood loss were similar in the two groups. Based on the pooled results, we suggested that AR can provide more precise acetabular cup placement than conventional methods in THA.

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.

Total Hip Arthroplasty: An Update on Navigation, Robotics, and Contemporary Advancements

While total hip arthroplasty (THA) remains effective for improvement of pain and function in patients with osteoarthritis and avascular necrosis, there remain areas of continued pursuit of excellence, including decreasing rates of dislocation, leg length discrepancy, implant loosening, and infection. This review article covers several bearing surfaces and articulations, computer-assisted navigation and robotic technology, and minimally invasive surgical approaches that have sought to improve such outcomes. Perhaps the most significant improvement to THA implant longevity has been the broad adoption of highly cross-linked polyethylene, with low wear rates. Similarly, navigation and robotic technology has proven to more reproducibly achieve intraoperative component positioning, which has demonstrated clinical benefit with decreased risk of dislocation in a number of studies. Given the projected increase in THA over the coming decades, continued investigation of effective incorporation of technology, soft tissue-sparing approaches, and durable implants is imperative to continued pursuit of improved outcomes in THA.

Preliminary study of short-term outcomes and learning curves of robotic-assisted THA: comparison between closed platform robotic system and open platform robotic system

BACKGROUND

Both closed platform and open platform robotic-assisted total hip arthroplasty (THA) have recently been recommended as a viable treatment option for achieving accurate positioning of components. Yet, limited studies paid attention to the differences between the closed platform robotic system and the open platform robotic system. Hence, this study aimed to investigate clinical outcomes, radiographic outcomes, complication rates and learning curve of two systems.

MATERIALS AND METHODS

We retrospectively included 62 patients (31 closed robotic system and 31 open robotic system) who underwent THA between February 2021 and January 2023. The demographics, operating time, cup positioning, complications and hip Harris score were evaluated. Learning curves of operation time was conducted using cumulative sum (CUSUM) analysis.

RESULTS

There were no differences in surgical time (76.7 ± 12.1 min vs. 72.3 ± 14.8 min), estimated blood loss (223.2 ± 13.2 ml vs. 216.9 ± 17 ml) and Harris Hip score (HHS) between closed platform robotic system and the open platform robotic system. The closed robotic system and the open robotic system were associated with a learning curve of 9 cases and 7 cases for surgical time respectively, based on the satisfying rate of Lewinnek's safe zone outliers (1/31, 96.8%) and no occurrence of complication. Both robotic systems had significant reduction in overall surgical time, the duration of acetabulum registration, and estimated blood loss between learning phase and proficiency phase.

CONCLUSION

The authors suggest that the surgical outcomes and safe zone outlier rate of the open robotic-assisted THA were similar to those of the closed robotic-assisted THA. These two robotic-assisted are associated with comparable learning curves and both have the precise positioning of acetabular component. From learning phase to proficiency phase, the rate of positions within the safe zone differed only marginally (88.9-100% vs. 85.7-100%) based on a rather low number of patients. This is not a statistically significant difference. Therefore, we suggest that THA undergoing with the robotic-assisted system is the relatively useful way to achieve planned acetabular cup position so far.

Perioperative safety and efficacy of robot-assisted total hip arthroplasty in ERAS-managed patients: a pilot study

AIMS

Robot-assisted total hip arthroplasty (rTHA) boasts superior accuracy in implant placement, but there is a lack of effective assessment in perioperative management in the context of enhanced recovery after surgery (ERAS). This study aimed to compare the effectiveness and safety of rTHA versus conventional total hip arthroplasty (cTHA) in ERAS-managed patients.

METHODS

In this prospective trial, a total of 60 eligible patients aged between 18 and 80 years were randomly divided into two groups to undergo either rTHA or cTHA. The primary outcomes included blood loss parameters. Secondary outcomes were the duration of the operation, surgical time, WOMAC pain score, WOMAC stiffness score, WOMAC physical function score, Harris score, and postoperative complications.

RESULTS

The study cohort analyzed 59 eligible participants, 30 of whom underwent rTHA and 29 of whom underwent cTHA. Analysis could not be conducted for one patient due to severe anemia. Notably, the cTHA group had a significantly shorter surgical time than the rTHA group (69.49 ± 18.97 vs. 104.20 ± 19.63 min, P < 0.001). No significant differences were observed between the rTHA and cTHA groups for blood loss parameters, including total blood loss (1280.30 ± 404.01 vs. 1094.86 ± 494.39 ml, P = 0.137) and drainage volume (154.35 ± 121.50 vs. 159.13 ± 135.04 ml, P = 0.900), as well as intraoperative blood loss (126.67 ± 38.80 vs. 118.52 ± 60.68 ml, P = 0.544) and hidden blood loss (982.43 ± 438.83 vs. 784.00 ± 580.96 ml, P = 0.206). Only one patient in the cTHA group required allogeneic blood transfusion. At 3 months postoperatively, both groups showed improvements in WOMAC pain score, WOMAC stiffness score, WOMAC physical function score, and Harris score, with no significant differences found between the two groups. Few complications were reported in both groups without significant differences.

CONCLUSIONS

Despite the longer surgical time, rTHA did not negatively affect blood loss, pain, or functional recovery or lead to an increased risk of complications in ERAS-managed patients, suggesting that rTHA can be safely and effectively incorporated into an ERAS program for primary THA.

Does robotic-assisted surgery improve outcomes of total hip arthroplasty compared to manual technique? A systematic review and meta-analysis

BACKGROUND

Robot-assisted total hip arthroplasty (THA) is an emerging technology that claims to position implants with very high accuracy. However, there is currently limited data in literature on whether this improved accuracy leads to better long-term clinical outcomes. This systematic review compares the outcomes of THA done with the help of robotic assistance (RA) to those done with conventional manual techniques (MTs).

METHODS

Four electronic databases were searched for eligible articles that directly compared robot-assisted THA to manual THA and had data on the radiological or clinical outcomes of both. Data on various outcome parameters were collected. Meta-analysis was conducted using a random-effects model with 95% CIs.

RESULTS

A total of 17 articles were found eligible for inclusion, and 3600 cases were analysed. Mean operating time in the RA group was significantly longer than in the MT group. RA resulted in significantly more acetabular cups being placed inside Lewinnek's and Callanan's safe zones (p<0.001) and had significantly reduced limb length discrepancy compared with MT. There were no statistically significant differences in the two groups in terms of incidence of perioperative complications, need for revision surgery and long-term functional outcome.

CONCLUSION

RA leads to highly accurate implant placement and leads to significantly reduced limb length discrepancies. However, the authors do not recommend robot-assisted techniques for routine THAs due to lack of adequate long-term follow-up data, prolonged surgical times and no significant differences in the rate of complications and implant survivorship compared with conventional MTs.

Total Hip Arthroplasty: So Hip It Hurts

Total hip arthroplasty (THA) has become a standard surgical intervention for patients with hip joint disorders [...].

Forgotten joint score is worse when the affected leg perceived longer than shorter after total hip arthroplasty

BACKGROUND

One of the causes of patient dissatisfaction after total hip arthroplasty (THA) is leg length discrepancy (LLD). Even when radiographic LLD (R-LLD) is within 5 mm, some people perceive the affected side to be longer, while others perceive it is shorter. The purpose of this study was to investigate the relationship between perceived LLD (P-LLD), R-LLD, and Forgotten Joint Score (FJS-12) after THA.

METHODS

A retrospective study of 164 patients with unilateral hip disease was conducted. Based on P-LLD after THA, they were classified into three categories: perceived short (PS 21 patients), no LLD (PN 121 patients), and perceived long (PL 22 patients). On the other hand, based on R-LLD after THA, they were divided into <  - 5 mm (RS 36 patients), - 5 mm ≤ x < 5 mm (RN 99 patients), and 5 mm ≥ (RL 29 patients), respectively. The proportion of P-LLD in the RN group was also evaluated. In each group, the relationship between P-LLD, R-LLD and FJS-12 was investigated.

RESULTS

After THA, the PL group had significantly worse FJS-12 (PS: 68.3 ± 26.2, PN: 75.0 ± 20.9, PL: 47.3 ± 25.2, P < .0001). In the R-LLD evaluation, there was no difference in FJS-12 among the three groups (RS: 73.7 ± 21.1, RN: 70.0 ± 24.5, RL: 67.7 ± 25.4, P < .53). The RN group perceived leg length to be longer (RN-PL) in 12.1% of cases, and the RN-PL groups had significantly worse FJS-12 (RN-PS: 65.4 ± 24.8, RN-PN: 73.8 ± 23.1, RN-PL: 41.8 ± 27.6, P < .0001).

CONCLUSION

One year after THA, patients with longer P-LLD had worse FJS-12, even if the R-LLD was less than 5 mm.

The Top Three Burning Questions in Total Hip Arthroplasty

Total hip arthroplasty (THA) for end-stage osteoarthritis is one of the most effective surgical treatments in medicine. Impressive outcomes have been well documented in the literature with patients gaining ambulation and recovery of hip joint function. Nevertheless, there are still debatable issues and controversies that the orthopedic community has not been able to provide a definitive answer for. This review is focused on the current three most debatable issues surrounding the THA procedure: (1) new cutting-edge technology, (2) spinopelvic mobility, and (3) fast-track protocols. The scope of the herein narrative review is to analyze the debatable issues surrounding the three aforementioned topics and conclude the best contemporary clinical approaches regarding each issue.

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.

Perioperative management of leg-length discrepancy in total hip arthroplasty: a review

Leg-length discrepancy (LLD) presents a significant management challenge to orthopedic surgeons and remains a leading cause of patient dissatisfaction and litigation after total hip arthroplasty (THA). Over or under-lengthening of the operative extremity has been shown to have inferior outcomes, such as dislocation, exacerbation of back pain and sciatica, and general dissatisfaction postoperatively. The management of LLD in the setting of THA is multifactorial, and must be taken into consideration in the pre-operative, intra-operative, and post-operative settings. In our review, we aim to summarize the best available practices and techniques for minimizing LLD through each of these phases of care. Pre-operatively, we provide an overview of the appropriate radiographic studies to be obtained and their interpretation, as well as considerations to be made when templating. Intra-operatively, we discuss several techniques for the assessment of limb length in real time, and post-operatively, we discuss both operative and non-operative management of LLD. By providing a summary of the best available practices and strategies for mitigating the impact of a perceived LLD in the setting of THA, we hope to maximize the potential for an excellent surgical and clinical outcome.

The Ability of Robot-Assisted Total Knee Arthroplasty in Matching the Efficiency of Its Conventional Counterpart at an Orthopaedic Specialty Hospital

BACKGROUND

Robot-assisted total knee arthroplasty (RA-TKA) has become a popular technology. Studies have investigated the learning curve for surgeons incorporating RA-TKA into practice, but less is known regarding the change in operative efficiency when introducing RA-TKA into a facility. The purpose of this study was to investigate the effects of RA-TKA on operative and turnover time at an orthopaedic specialty hospital.

METHODS

A total of 148 cases (74 RA-TKA and 74 conventional TKA [C-TKA]) performed by 2 surgeons with previous robotic experience were identified following the introduction of RA-TKA at our facility. Patient demographics, comorbidities, and operative times (ie, wheels-in to incision, incision to closure, closure to wheels-out, and turnover time) were recorded. Cumulative summation analyses were used to investigate learning curves of factors extraneous to surgeon proficiency with RA-TKA.

RESULTS

While RA-TKA had a slightly longer set up (3 minutes; range, 12-45), surgical (5 minutes; range, 33-118), and breakdown time (3 minutes; range, 2-7), there was no difference in turnover time between the groups. The learning curve for surgeon A was 6 robotic cases, whereas surgeon B demonstrated no learning curve. There was no identifiable learning curve for turnover time.

CONCLUSION

There was a mean of 8 minutes of increased time required to perform a RA-TKA compared to C-TKA. However, these small increases for the RA-TKA group for set-up, surgical, and breakdown times are not likely to be clinically relevant compared to the C-TKA. It appears that the RA-TKA technology was able to be incorporated into this specialty hospital with minimal changes to surgical efficiency.

Accuracy of acetabular component alignment with surgical guidance systems during hip arthroplasty

BACKGROUND

Navigation in total hip arthroplasty has been shown to improve acetabular positioning and can decrease the incidence of mal-positioned acetabular components. This study aimed to assess two surgical guidance systems by comparing intra-operative measurements of acetabular component inclination and anteversion with a post-operative CT scan.

METHODS

We prospectively collected intra-operative navigation data from 102 hips receiving conventional THA or hip resurfacing arthroplasty through either a direct anterior or posterior approach. Two guidance systems were used simultaneously: an inertial navigation system (INS) and an optical navigation system (ONS). Acetabular component anteversion and inclination were measured on a post-operative CT.

RESULTS

The average age of the patients was 64 years (range: 24-92) and the average BMI was 27 kg/m² (range 19-38). 52% had hip surgery through an anterior approach. 98% of the INS measurements and 88% of the ONS measurements were within 10° of the CT measurements. The mean (and standard deviation) of the absolute difference between the postoperative CT and the intra-operative measurements for inclination and anteversion were 3.0° (2.8) and 4.5° (3.2) respectively for the ONS, along with 2.1° (2.3) and 2.4° (2.1) respectively for the INS. There was a significantly lower mean absolute difference to CT for the INS when compared to ONS in both anteversions (p < 0.001) and inclination (p = 0.02).

CONCLUSIONS

We found that both inertial and optical navigation systems allowed for adequate acetabular positioning as measured on postoperative CT, and thus provide reliable intraoperative feedback for optimal acetabular component placement.

LEVEL OF EVIDENCE

Therapeutic Level II.

Handheld Navigation Improves Accuracy in Direct Anterior Total Hip Replacement

Background

This study sought to determine the accuracy in placing the acetabular component, estimation of leg length, offset, radiation time and dose, and operative time using a handheld navigation device compared to conventional anterior total hip arthroplasty (THA). It also examined the learning curve of the handheld navigation device.

Methods

Data were prospectively collected for a consecutive series of 159 THAs; 99 THAs with handheld navigation and 60 conventional THAs. Thresholds of <5°, ≥5° to <10°, and ≥10° for acetabular inclination and version and thresholds of <5 mm, ≥5 mm to <10 mm, and ≥10 mm for leg-length and combined offset discrepancy were used to assess accuracy. Fluoroscopy time and exposure, operative time, and complications were compared. Learning curve was determined using operative time. Statistical analysis was performed for the different accuracy thresholds with P values set a <0.05 for significance.

Results

The handheld navigation device demonstrated a mean accuracy of 3.2° and 1.8° for version and inclination, respectively. The handheld navigation group had significantly fewer outliers in version (P < .001), inclination (P < .001), leg-length discrepancy (P < .001), and offset discrepancy (P < .001). Fluoroscopic dose and time (P < .001) were lower in the handheld navigation cohort. The learning curve for handheld navigation was 31-35 cases. The mean operative time after the learning curve was similar to that in the conventional fluoroscopy group (P = .113).

Conclusions

Handheld navigation technology provided more accurate results while mitigating radiation exposure to the surgeon and patient. There were fewer outliers in the handheld navigation group. After the learning curve, all metrics improved in accuracy, and operative time was similar to that of the conventional technique.

Comparison of Postoperative Instability and Acetabular Cup Positioning in Robotic-Assisted Versus Traditional Total Hip Arthroplasty

BACKGROUND

Robotic-assisted total hip arthroplasty (R-THA) affords precision yet uncertain clinical benefits. This study compares dislocation rates and related revisions between R-THA and manual total hip arthroplasty (M-THA). Secondarily we evaluated cup position, patient-reported outcome measures (PROMs), and postoperative complications.

METHODS

A three-surgeon cohort study was conducted on 2247 consecutive patients (1724 M-THA and 523 R-THA) who received a primary THA between January 2014 and June 2020 at a single hospital. Demographics, PROMs, emergency department visits, readmissions, and 90-day complications were collected via the Michigan Arthroplasty Registry Collaborative Quality Initiative. Chart review yielded instability occurrence with an average follow-up of 4 years. Multivariate regression analysis was performed, and a sample of 368 radiographs, including all dislocations, were assessed.

RESULTS

There were significantly lower rates of dislocation in R-THA (0.6%) vs M-THA (2.5%; Multivariate odds ratio 3.74, P < .046). All cases of unstable R-THA were successfully treated conservatively, whereas 46% of unstable M-THA were revised for recurrent instability. Cup anteversion (25.6° ± 5.4° R-THA vs 20.6° ± 7.6° M-THA) was greater, and cup inclination (42.5° ± 5.3° R-THA vs 47.0° ± 6.7° M-THA) was lower in the R-THA group (P < .05). No significant differences were noted for demographics, PROMs, or other complications (P > .05).

CONCLUSION

R-THA resulted in less than one-fourth the dislocation rate compared to M-THA and no revision for instability. It was associated with no difference in PROMs or other early complications. The influence of R-THA on stability goes beyond simply cup positioning and deserves further study.

20-year hip survivorship and patient-reported outcome measures after transpositional osteotomy of the acetabulum for dysplastic hips

AIMS

Although periacetabular osteotomies are widely used for the treatment of symptomatic dysplastic hips, long-term surgical outcomes and patient-reported outcome measures (PROMs) are still unclear. Accordingly, we assessed hip survival and PROMs at 20 years after transpositional osteotomy of the acetabulum (TOA).

METHODS

A total of 172 hips in 159 patients who underwent TOA were followed up at a mean of 21.02 years (16.6 to 24.6) postoperatively. Kaplan-Meier analysis was used to assess survivorship with an endpoint of total hip arthroplasty (THA). PROMs included the visual analogue scale (VAS) Satisfaction, VAS Pain, Oxford Hip Score (OHS), and Forgotten Joint Score-12 (FJS-12). Thresholds for favourable outcomes for OHS (≥ 42) and FJS-12 (≥ 51) were obtained using the receiver operating characteristic curve with VAS Satisfaction ≥ 50 and VAS Pain < 20 as anchors.

RESULTS

THA was performed on 37 hips (21.5%) by the latest follow-up. Kaplan-Meier analysis indicated that the hip survival rate at 20 years was 79.7% (95% confidence interval (CI) 73.7 to 86.3). Multivariate analysis showed that preoperative Tönnis grade significantly influenced hip survival. Tönnis grades 0, 1, and 2 were associated with 20-year survival rates of 93.3% (95% CI 84.8 to 100), 86.7% (95% CI 79.8 to 94.3), and 54.8% (95% CI 41.5 to 72.3), respectively. More than 60% of the patients exhibited favourable PROMs. An advanced Tönnis grade at the latest follow-up and a higher BMI were both significantly associated with unfavourable OHS, but not with other PROMs.

CONCLUSION

This study demonstrated the durability of TOA for hips with Tönnis grades 0 to 1 at 20 years. While the presence of advanced osteoarthritis and higher BMI was associated with lower hip functions (OHS), it was not necessarily associated with worse patient satisfaction and joint awareness. Cite this article: Bone Joint J 2022;104-B(7):767-774.

Intraoperative Technology Use Improves Accuracy of Functional Safe Zone Targeting in Total Hip Arthroplasty

BACKGROUND

Targets of acetabular inclination and anteversion have been suggested based on a patient's spinopelvic mobility. Current methods in total hip arthroplasty (THA) include manual instrumentation, computer-assisted navigation, and robotic-assisted surgery. This study aims to compare the accuracy of these 3 methods in targeting the functional safe zone.

METHODS

This is a prospective multicenter study including a series of 251 consecutive primary posterior THA patients from April 2019 to January 2021. Preoperative lateral standing and sitting spinopelvic radiographs were obtained. Each patient was classified using the Hip-Spine Classification. A functional safe zone plan was determined. Surgeons used their preferred method (manual instrumentation, computer-assisted, or robotic-assisted). Postoperative anteversion and inclination was measured and compared to the preoperative plan. Mean differences between preoperative and postoperative values were calculated. Welch's t-test was used to assess significant between-group differences with P < .05 considered significant.

RESULTS

Of the 249 patients, there were 63 manual instrumentation, 68 computer-assisted navigation, and 118 robotic-assisted surgery. Robotic-assisted surgery (rTHA) was significantly more accurate in targeting anteversion (1 ± 2) compared to manual instrumentation (mTHA; 7 ± 6, P < .001) and computer-assisted navigation (cTHA; 6 ± 6, P < .001). rTHA was also significantly more accurate in targeting inclination (1 ± 1) compared to mTHA (8 ± 7, P < .001) and cTHA (6 ± 7, P < .001). Although cTHA had greater accuracy in targeting both inclination and anteversion compared to mTHA, these differences were not statistically significant.

CONCLUSION

Robotic-assisted surgery was more accurate than both computer-assisted navigation and manual instrumentation in targeting the functional safe zone in primary THA. Further research is needed to evaluate the effect of improved accuracy on dislocation rates.

Robotic Assistance for Posterior Approach Total Hip Arthroplasty Is Associated With Lower Risk of Revision for Dislocation When Compared to Manual Techniques

BACKGROUND

Robotic-assistance total hip arthroplasty (RA-THA) and computer navigation THA (CN-THA) have been shown to improve accuracy of component positioning compared to manual techniques; however, controversy exists regarding clinical benefit. Moreover, these technologies may expose patients to risks. The purpose of this study is to compare rates of intraoperative fracture and complications requiring reoperation within 1 year for posterior approach RA-THA, CN-THA, and THA with no technology (Manual-THA).

METHODS

In total, 13,802 primary, unilateral, elective, posterior approach THAs (1770 RA-THAs, 3155 CN-THAs, and 8877 Manual-THAs) were performed at a single institution between 2016 and 2020. Intraoperative fractures and reoperations within 1 year of the index procedure were identified. Cohorts were balanced using inverse probability of treatment weight based on age, gender, body mass index, femoral cementation, history of spine fusion, and Charlson Comorbidity Index. Logistic regression was performed to create odds ratios for complications. Additional regression analysis for dislocation was performed, adjusting for dual mobility and femoral head size.

RESULTS

There were no differences in intraoperative fracture and postoperative complication rates between the groups (P = .521). RA-THA had a 0.3 odds ratio (95% confidence interval 0.1-0.9, P = .046) compared to Manual-THA for reoperation due to dislocation. CN-THA had an odds ratio of 3.0 for reoperation due to dislocation (95% confidence interval 0.8-11.3, P = .114) compared to RA-THA. The remaining complication odds ratios, including those for infection, loosening, dehiscence, and "other" were similar between the groups.

CONCLUSION

RA-THA is associated with lower risk of revision for dislocation within 1 year of index surgery, when compared to Manual-THA performed through the posterior approach.