Health Care Utilization and Payer Cost Analysis of Robotic Arm Assisted Total Knee Arthroplasty at 30, 60, and 90 Days

Comparing a robotic imageless second-generation system to traditional instrumentation in total knee arthroplasty: A matched cohort analysis

Introduction

Robotic-assisted total knee arthroplasty (rTKA) has gained interest from patients and surgeons alike. Robotic systems assist with gap balancing and bone cut accuracy, which can theoretically minimize post-operative pain by decreasing soft tissue damage. This study compared perioperative results, 30- and 90-day complications, patient-reported outcomes (PROs), and survivorship to all-cause revisions between patients undergoing traditional versus rTKA.

Methods

A total of 430 TKAs (215 rTKA, 215 traditional) by two fellowship trained arthroplasty surgeons were retrospectively reviewed from 2017 to 2022. All rTKAs were performed using the CORI Surgical System (Smith & Nephew, Memphis, Tennessee). Cohorts were propensity score matched by age, sex, body mass index, and American Society of Anesthesiologist classification. Blood loss, surgical times, length of stays, 30- and 90-day complications, pain scores and PROs were compared with univariable analyses. Cox regression analyses evaluated survival to all-cause revisions.

Results

Patients undergoing rTKA had a higher incidence of discharge home (86.5 %-60.0 %) (p < 0.01). There was no difference in blood loss or surgical time. rTKA pain scores were lower in-hospital mean 2 (range, 0 to 9) vs 3 (range, 0 to 9) (p = 0.02) as well as at one-year post-operatively, mean 1 (range, 0 to 7) vs 2 (range, 0 to 10) (p = 0.02). Cox hazard ratio demonstrated no difference in survival to all-cause revisions (HR 1.3; CI 0.5 to 3.7) (p = 0.64).

Conclusion

This matched cohort analysis demonstrated potential short-term benefits associated with imageless second generation rTKA including improved early post-operative pain, without compromising survivorship to all-cause revisions.

Understanding economic analysis and cost-effectiveness of CT scan-guided, 3-dimensional, robotic-arm assisted lower extremity arthroplasty: a systematic review

Aim: The overall goal of this review was to examine the cost-utility of robotic-arm assisted surgery versus manual surgery. Methods: We performed a systematic review of all health economic studies that compared CT-based robotic-arm assisted unicompartmental knee arthroplasty, total knee arthroplasty and total hip arthroplasty with manual techniques. The papers selected focused on various cost-utility measures. In addition, where appropriate, secondary aims encompassed various clinical outcomes (e.g., readmissions, discharges to subacute care, etc.). Only articles directly comparing CT-based robotic-arm assisted joint arthroplasty with manual joint arthroplasty were included, for a resulting total of 21 reports. Results: Almost all twenty-one studies demonstrated a positive effect of CT scan-guided robotic-assisted joint arthroplasty on health economic outcomes. For studies reporting on 90-day episodes of costs, 10 out of 12 found lower costs in the robotic-arm assisted groups. Conclusion: Robotic-arm assisted joint arthroplasty patients had shorter lengths of stay and cost savings based on their 90-day episodes of care, among other metrics. Payors would likely benefit from encouraging the use of this CT-based robotic technology.

Systematic review and meta-analysis of economic and healthcare resource utilization outcomes for robotic versus manual total knee arthroplasty

The introduction of robotics in orthopedic surgery has led to improved precision and standardization in total knee arthroplasty (TKA). Clinical benefits of robotic versus manual TKA have been well established; however, evidence for economic and healthcare resource utilization outcomes (HRU) is lacking. The primary objective of this study was to compare economic and HRU outcomes for robotic and manual TKA. The secondary objective was to explore comparative robotic and manual TKA pain and opioid consumption outcomes. Multi-database literature searches were performed to identify studies comparing robotic and manual TKA from 2016 to 2022 and meta-analyses were conducted. This review included 50 studies with meta-analyses conducted on 35. Compared with manual TKA, robotic TKA was associated with a: 14% reduction in hospital length of stay (P = 0.022); 74% greater likelihood to be discharged to home (P < 0.001); and 17% lower likelihood to experience a 90-day readmission (P = 0.043). Robotic TKA was associated with longer mean operating times (incision to closure definition: 9.27 min longer, P = 0.030; general operating time definition: 18.05 min longer, P = 0.006). No differences were observed for total procedure cost and 90-day emergency room visits. Most studies reported similar outcomes for robotic and manual TKA regarding pain and opioid use. Coupled with the clinical benefits of robotic TKA, the economic impact of using robotics may contribute to hospitals' quality improvement and financial sustainability. Further research and more randomized controlled trials are needed to effectively quantify the benefits of robotic relative to manual TKA.

Fostering Excellence in Knee Arthroplasty: Developing Optimal Patient Care Pathways and Inspiring Knowledge Transfer of Advanced Surgical Techniques

Osteoarthritis of the knee is common. Early sports trauma or cartilage defects are risk factors for osteoarthritis. If conservative treatment fails, partial or total joint replacement is often performed. A joint replacement aims to restore physiological biomechanics and the quality of life of affected patients. Total knee arthroplasty is one of the most performed surgeries in musculoskeletal medicine. Several developments have taken place over the last decades that have truly altered the way we look at knee arthroplasty today. Some of the fascinating aspects will be presented and discussed in the present narrative review.

Learning curve for robot-assisted knee arthroplasty; optimizing the learning curve to improve efficiency

The introduction of robot-assisted (RA) systems in knee arthroplasty has challenged surgeons to adopt the new technology in their customized surgical techniques, learn system controls, and adjust to automated processes. Despite the potential advantages of RA knee arthroplasty, some surgeons remain hesitant to adopt this novel technology owing to concerns regarding the cumbersome adaptation process. This narrative review addresses the learning-curve issues in RA knee arthroplasty based on the existing literature. Learning curves exist in terms of the operative time and stress level of the surgical team but not in the final implant positions. The factors that reduce the learning curve are previous experience with computer-assisted surgery (including robot or navigation systems), specialization in knee surgery, high volume of knee arthroplasty, optimization of the RA workflow, sequential implementation of RA surgery, and consistency of the surgical team. Worse clinical outcomes may occur in the early postoperative period, but not in the later period, in RA knee arthroplasty performed during the learning phase. No significant differences were observed in implant survival or complication rates between the RA knee arthroplasties performed during the learning and proficiency phases.

A novel robot-assisted knee arthroplasty system (ROSA) and 1-year outcome: A single center experience

BACKGROUND

Total knee arthroplasty is a successful procedure in the treatment of knee osteoarthritis. Searches in surgical technique have focused surgeons in particular on implant alignment. For this purpose, the use of robot-assisted total knee arthroplasty has become increasingly common in the last 10 years.

METHODS

A total of 46 patients (66 knees) who were operated for knee osteoarthritis with Robotic Surgical Assistant (ROSA, Zimmer-Biomet, Warshaw, Indiana, USA) between 2021 and 2023 were included in the study. Preoperative planning and intraoperative incision time, total surgical time, range of motion and follow-up time recorded. Oxford knee scores and knee society scores (KSS) of the patients were compared before and after surgery. At the last follow-up Forgotten Joint Score and the sagittal and coronal plane alignments were evaluated.

RESULTS

Preoperative mean Oxford score of the right knee of the patients was 18.5 ± 3.2, post-surgery mean Oxford score progressed to 43.5 ± 2.2. While the preoperative left knee Oxford score of the patients was 16.9 ± 2.3, the mean left knee Oxford score improved to 43.4 ± 2.2 postoperatively. The mean KSS score of the patients' right knee preoperatively was 49.7 ± 3.5, and progressed to 89.2 ± 4.7 postoperatively. While the preoperative mean left knee KSS score of the patients was 46.5 ± 4.3, the mean KSS score improved to 89.8 ± 3.2 postoperatively. The mean Forgotten Joint Score of the left knee at the last follow-up of the patients was 77.4 ± 3.8, while the mean Forgotten Joint Score of the right knee was 75.4 ± 5.9.

CONCLUSION

The results of ROSA-supported knee arthroplasty found to be functionally successful.

Advantages of robotic arm-assisted total hip arthroplasty: a 90-day episode-of-care clinical utility and cost analysis

Aim: Determine the clinical utility and economic differences over a 90-day period between robotic arm-assisted total hip arthroplasty (RATHA) and manual total hip arthroplasty (MTHA). Methods: Leveraging a nationwide commercial payer database, pre-covid THA procedures were identified. Following a 1:5 propensity score match, 1732 RATHA and 8660 MTHA patients were analyzed. Index costs, index lengths of-stay, and 90-day episode-of-care utilization and costs were evaluated. Results: Episode of care costs for RATHA was found to be $1573 lower compared with MTHA (p < 0.0001). Post-index hospital utilization was significantly less likely to occur for RATHA compared with MTHA. Total index costs were also significantly lower for RATHA versus MTHA (p < 0.0001). Conclusion: Index and post-index EOC hospital utilization and costs were lower for RATHA compared with MTHA.

Is the femoral intramedullary alignment already actual in total knee arthroplasty?

Clinical outcomes and overall alignment after total knee arthroplasty (TKA) depend on femoral component positioning in the sagittal and the coronal plane, making choice of the distal femoral cutting guide crucial. Currently, there is no consensus on the potential advantage of an extramedullary (EM) guide compared to an intramedullary (IM) guide in TKA. The IM guide is the most widely used system for making the distal femoral cut although evidence for its superiority over the EM guide is lacking. However, inaccuracies arising with the IM guide include location of the rod entry point in the coronal plane, femoral canal diameter, femoral bowing, and structural features of the rod. Furthermore, the invasive procedure is associated with increased risk of postoperative blood loss, thromboembolic complications, and intraoperative fractures. While the EM guide has no such difficulties, its accuracy depends on the instruments used. Studies have reported results not inferior to the IM guide and a lower number of postoperative complications. Patient-specific instrumentation (PSI) and robotic and computer-assisted TKA have achieved excellent clinical and radiographic results and can overcome the problems inherent to the IM and the EM guide. Authors performed a systematic review of the literature and proposed a narrative review to summarize the characteristics of the IM and the EM guide and compare the advantages and disadvantages of each, as well as their limitations in comparison with new technologies. Authors also expressed their expert opinion.

Index surgery and ninety day re-operation cost comparison of robotic-assisted versus manual total knee arthroplasty

INTRODUCTION

This study looks to compare early costs of index surgery and re-operations of robotic-assisted total knee arthroplasties (rTKA) and manual total knee arthroplasty (mTKA) re-operations within 90 days.

MATERIAL AND METHODS

The Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database was queried for patients undergoing rTKA and mTKA at our institution from January 1st, 2018, to March 31st, 2021. Primary outcomes were the day of surgery and overall encounter variable direct costs (VDC). Secondary outcomes included 90-day re-operations and costs.

RESULTS

One thousand two hundred seventy-six (21.2%) patients were in the rTKA cohort, while 4740 (78.8%) were in the mTKA cohort. When comparing rTKA to mTKA, rTKA had higher median total encounter costs (p < 0.001) and higher encounter VDC costs (p < 0.001). TKA had higher day of surgery total VDC (p < 0.001), VDC supplies (p < 0.001), and VDC of post-op recovery (p < 0.001). Multivariate linear regression showed no relationship with age, BMI, OR time, or LOS with cost for rTKA or mTKA.

CONCLUSION

Results from our study show that rTKA is associated with a higher index surgery costs, and no difference in 90-day re-operation costs. The main factor driving increased cost is supply cost, with other variables between too small in difference to make a significant financial impact. Future studies should focus on post-operative costs including readmission and episode of care costs and should consider cost to the payor as opposed to VDC. rTKA will become more common, and other institutions may need to take a closer financial look at this more novel instrumentation before adoption.

LEVEL OF EVIDENCE

III, retrospective cohort.

Can Technology Assistance be Cost Effective in TKA? A Simulation-Based Analysis of a Risk-prioritized, Practice-specific Framework

BACKGROUND

Robotic, navigated, and patient-specific instrumentation (PSI) TKA procedures have been introduced to improve component placement precision and improve implant survivorship and other clinical outcomes. However, the best available evidence has shown that these technologies are ineffective in reducing revision rates in the general TKA patient population. Nonetheless, it seems plausible that these technologies could be an effective and cost-effective means of reducing revision risk in clinical populations that are at an elevated risk of revision because of patient-specific demographics (such as older age at index surgery, elevated BMI, and being a man). Since clinical trials on this topic would need to be very large, a simulation approach could provide insight on which clinical populations would be the most promising for analysis.

QUESTIONS/PURPOSES

We conducted a simulation-based analysis and asked: (1) Given key demographic parameters characterizing a patient population, together with estimates of the precision achievable with selected forms of technology assistance in TKA, can we estimate the expected distributions of anticipated reductions in lifetime revision risk for that population and the associated improvements in quality-adjusted life years (QALYs) that would be expected to result? (2) Are there realistic practice characteristics (such as combinations of local patient demographics and capital and per-procedure costs) for which applying a per-patient risk-prioritized policy for using technology-assisted TKA could be considered cost-effective based on projected cost savings from reductions in revision rates?

METHODS

We designed simulations of hypothetical practice-specific clinical scenarios, each characterized by patient volume, patient demographics, and technology-assisted surgical technique, using demographic information drawn from other studies to characterize two contrasting simulated clinical scenarios in which the distributions of factors describing patients undergoing TKA place one population at a comparatively elevated risk of revision (elevated-risk population) and the second at a comparatively reduced risk of revision (lower-risk population). We used results from previous systematic reviews and meta-analyses to estimate the implant precision in coronal plane alignment for patient-specific instrumentation, navigated, and robotic technology. We generated simulated TKA patient populations based on risk estimates from large clinical studies, structured reviews, and meta-analyses and calculated the patient-specific reduction in the revision risk and the change in QALYs attributable to the technology-assisted intervention in each of the two simulated clinical scenarios. We also incorporated a sensitivity analysis, incorporating variations in the effect size of deviations from overall coronal alignment on revision risk and difference in health state utilities acquired through a structured review process. We then simulated the outcomes of 25,000 operations per patient using the precisions associated with the conventional TKA technique, the three technology-assisted techniques, and a hypothetical technology-assisted intervention that could consistently deliver perfectly neutral overall coronal alignment, which is unachievable in practice. A risk-prioritized treatment policy was emulated by ordering the simulated patients from the highest to lowest predicted increase in QALYs, such that simulated patients who would see the greatest increase in the QALYs (and therefore the greatest reduction in lifetime revision risk) were the patients to receive technology-assisted TKA intervention in a practice. We used cost estimates acquired through a structured review process and calculated the net added costs of each of the three technology-assisted techniques as a function of the percent utilization (proportion of patients treated with technology assistance in a practice), factoring in fixed costs, per-procedure variable costs, and savings occurring from the prevention of future revision surgery. Finally, we calculated the incremental cost-effectiveness ratio (ICER) and marginal cost-effectiveness ratio (MCER) for each technology-assisted technique for the two clinical scenarios. We then used a Monte Carlo approach to simulate variations in key patient risk, health state, and economic factors as well as to obtain a distribution of estimates for cost-effectiveness. We considered an intervention to be cost effective if either the ICER or MCER values were below USD/QALY 63,000.

RESULTS

For the lower-risk population, the median reduction in the revision risk was 0.9% (0.4% to 2.2%, extrema from the sensitivity analysis) and 1.8% (0.9% to 4.4%) for PSI and robotic TKA, respectively, and 1.9% (1.0% to 4.6%) for ideal TKA. In contrast, the median reduction in the revision risk in the elevated-risk clinical scenario was 2.0% (1.2% to 3.4%) and 4.6% (2.7% to 8.5%) for PSI and robotic TKA and 5.1% (3.0% to 9.4%) for ideal TKA. Estimated differences in the cumulative gain in QALYs attributable to technology-assisted TKA ranged from 0.6 (0.2 to 1.8) to 4.0 (1.8 to 10.0) QALYs per 100 patients, depending on the intervention type and clinical scenario. For PSI, we found treating 15% of patients in the lower-risk population and 77% in the elevated-risk population could meet the threshold for being considered cost effective. For navigated TKA systems offering high alignment precision, we found the intervention could meet this threshold for practice sizes of at least 300 patients per year and a percent utilization of 27% in the lower-risk population. In the elevated-risk population, cost-effectiveness could be achieved in practice volumes as small as 100 patients per year with a percent utilization of at least 6%, and cost savings could be achieved with a percent utilization of at least 45%. We found that robotic TKA could only meet the threshold for being considered cost-effectiveness in the lower-risk population if yearly patient volumes exceeded 600 and for a limited range of percent utilization (27% to 32%). However, in the elevated-risk patient population, robotic TKA with high alignment precision could potentially be cost effective for practice sizes as small as 100 patients per year and a percent utilization of at least 20% if a risk-prioritized treatment protocol were used.

CONCLUSION

Based on these simulations, a selective-use policy for technology-assisted TKA that prioritizes using technology assistance for those patients at a higher risk of revision based on patient-specific factors could potentially meet the cost-effectiveness threshold in selected circumstances (for example, primarily in elevated-risk populations and larger practice sizes). Whether it does meet that threshold would depend significantly on the surgical precision that can be achieved in practice for a given proposed technology as well as on the true local costs of using the proposed technology. We further recommend that any future randomized trials seeking to demonstrate possible effects of technology assistance on revision risk focus on clinical populations that are at higher risk of revision (such as, patient populations that are relatively younger, have higher BMIs, and higher proportions of men).

CLINICAL RELEVANCE

This study suggests that technology assistance is only likely to prove cost effective in selected circumstances rather than in all clinical populations and practice settings. In general, we project that surgical navigation is most likely to prove cost effective in the widest range of circumstances, that PSI may be cost effective or cost neutral in a moderate range of circumstances, and that robotic surgery is only likely to be cost effective in moderately large practices containing patients who are on average at an intrinsically elevated risk of revision.

Robotic-assisted TKA reduces surgery duration, length of stay and 90-day complication rate of complex TKA to the level of noncomplex TKA

INTRODUCTION

Complex primary total knee arthroplasties (TKA) are reported to be associated with excessive episode of care (EOC) costs as compared to noncomplex procedures. The impact of robotic assistance (rTKA) on economic outcome parameters in greater case complexity has not been described yet. The purpose of this study was to investigate economic outcome parameters in the 90-days postoperative EOC in robotic-assisted complex versus noncomplex procedures.

MATERIALS AND METHODS

This study is a retrospective, single-center review of 341 primary rTKAs performed between 2017 and 2020. Patient collective was stratified into complex (n = 218) and noncomplex TKA (n = 123) based on the presence of the following criteria: Obese BMI, coronal malalignment, flexion contracture > 10°, posttraumatic status, previous correction osteotomy, presence of hardware requiring removal during surgery, severe rheumatoid arthritis. Group comparison included surgery duration, length of stay (LOS), surgical site complications, readmissions, and revision procedures in the 90-days EOC following rTKA.

RESULTS

The mean surgery duration was marginally longer in complex rTKA, but showed no significant difference (75.26 vs. 72.24 min, p = 0.258), neither did the mean LOS, which was 8 days in both groups (p = 0.605). No differences between complex and noncomplex procedures were observed regarding 90-days complication rates (7.34 vs. 4.07%, p = 0.227), readmission rates (3.67 vs. 3.25%, p = 0.841), and revision rates (2.29 vs. 0.81%, p = 0.318).

CONCLUSIONS

Robotic-assisted primary TKA reduces the surgical time, inpatient length of stay as well as 90-days complication and readmission rates of complex TKA to the level of noncomplex TKA. Greater case complexity does not seem to have a negative impact on economic outcome parameters when surgery is performed with robotic assistance.

Robotic-Arm Assisted Technology's Impact on Knee Arthroplasty and Associated Healthcare Costs

Background: The number of total knee arthroplasties (TKA) carried out globally is expected to substantially rise in the coming decades. Consequently, focus has been increasing on improving surgical techniques and minimizing expenses. Robotic arm-assisted knee arthroplasty has garnered interest to reduce surgical errors and improve precision. Objectives: Our primary aim was to compare the episode-of-care cost up to 90 days for unicompartmental knee arthroplasty (UKA) and TKA performed before and after the introduction of robotic arm-assisted technology. The secondary aim was to compare the volume of UKA vs TKA. Methods: This was a retrospective study design at a single healthcare system. For the cost analysis, we excluded patients with bilateral knee arthroplasty, body mass index >40, postoperative infection, or noninstitutional health plan insurance. Costs were obtained through an integrated billing system and affiliated institutional insurance company. Results: Knee arthroplasty volume increased 28% after the introduction of robotic-assisted technology. The TKA volume increased by 17%, while the UKA volume increased 190%. Post introduction, 97% of UKA cases used robotic arm-assisted technology. The cost analysis included 178 patients (manual UKA, n = 6; robotic UKA, n = 19; manual TKA, n = 58, robotic TKA, n = 85). Robotic arm-assisted TKA and UKA were less costly in terms of patient room and operating room costs but had higher imaging, recovery room, anesthesia, and supply costs. Overall, the perioperative costs were higher for robotic UKA and TKA. Postoperative costs were lower for robotic arm-assisted surgeries, and patients used less home health and home rehabilitation. Discussion: Surgeons performed higher volumes of UKA, and UKA comprised a greater percentage of total surgical volume after the introduction of this technology. The selective cost analysis indicated robotic arm-assisted technology is less expensive in several cost categories but overall more expensive by up to $550 due to higher cost categories including supplies and recovery room. Conclusions: Our findings show a change in surgeons' practice to include increased incidence and volume of UKA procedures and highlights several cost-saving categories through the use of robotic arm-assisted technology. Overall, robotic arm-assisted knee arthroplasty cost more than manual techniques at our institution. This analysis will help optimize costs in the future.

Unsatisfactory accuracy of recent robotic assisting system ROSA for total knee arthroplasty

Purpose

The purpose of this study was to quantify accuracy of a recently FDA-approved robotic-assisted device.

Methods

Thirty-seven patients underwent TKA with the Robotic Surgical Assistant (ROSA) by the same operating surgeon and team over the course of 3 months. Intra-operative mechanical axis measurements, composed of alpha (α), beta (β), gamma (γ), and delta (δ) angles, and the hip-knee-ankle angle (HKA) were calculated by the ROSA. Post-operative mechanical implant angles were taken from 36″ stitched post-op films and measured in the PACS imaging system. Accuracy was assessed by comparing the percentage of postoperative long length films within 2° and 3° of the ROSA intra-operative plan.

Results

The ROSA system accurately calculated the HKA, α, and β angles (95% CI), but was inaccurate in calculating both γ and δ angles. Using a window of ± 3° accuracy, the HKA, α and β angles were accurate at levels of 89, 100 and 92% respectively. In contrast, the sagittal relationships were considerably less accurate at 77 and 74% for the γ and δ angles respectively. Subsequently, the proportion of cases within 2 and 3 degrees of the intra-operative plan for resection angles was considered accurate for HKA (73% within 2°, 89% within 3°), α (92% within 2°, 100% within 3°), and β (76% within 2°, 92% within 3°) angles, but considered inaccurate for γ (51% within 2°, 77% within 3°) and δ angles (57% within 2°, 74% within 3°).

Conclusions

This study demonstrated that while the ROSA system seems to accurately predict coronal plane resections in TKA, it falls short in the sagittal plane. Further research in these deficiencies can provide insight into the overall efficacy of robotic assisted surgery in TKA.

Level of Evidence

Level III Therapeutic Study.

Robotic Versus Manual Total Knee Arthroplasty in High Volume Surgeons: A Comparison of Cost and Quality Metrics

BACKGROUND

Robotic-assisted total knee arthroplasty (RTKA) was introduced to improve surgical accuracy and patient outcomes. However, RTKA may also increase operating time and add cost to TKA. This study sought to compare the differences in cost and quality measures between manual TKA (MTKA) and RTKA METHODS: All MTKAs and RTKAs performed between January 1, 2017 and December 31, 2019, by 6 high volume surgeons in each cohort, were retrospectively reviewed. Cohorts were propensity score matched. Operative time, length of stay (LOS), total direct cost, 90-day complications, utilization of postacute services, and 30-day readmissions were studied.

RESULTS

After one-to-one matching, 2392 MTKAs and 2392 RTKAs were studied. In-room/out-of-room operating time was longer for RTKA (139 minutes) than for MTKA (107 minutes) P < .0001, as was procedure time (RTKA 78 minutes; MTKA 70 minutes), P < .0001. Median LOS was equal for MTKA and RTKA (33 hours). Total cost per case was greater for RTKA ($11,615) than MTKA ($8674), P < .0001. Home health care was utilized more frequently after RTKA (38%) than MTKA (29%), P < .0001. There was no significant difference in 90-day complication rates. Thirty-day readmissions occurred more often after MTKA (4.9%) than RTKA (1.2%), P < .0001.

CONCLUSION

RTKA was a longer and costlier procedure than MTKA for experienced surgeons, without clinically significant differences in LOS or complications. Home health care was utilized more often after RTKA, but fewer readmissions occurred after RTKA. Longer term follow-up and functional outcome studies are required to determine if the greater cost of RTKA is offset by lower revision rates and/or improved functional results.

A 90-Day Episode-of-Care Analysis Including Computed Tomography Scans of Robotic-Arm Assisted versus Manual Total Knee Arthroplasty

In this observational, retrospective study, we performed economic analyses between robotic arm-assisted total knee arthroplasty (RATKA) and manual total knee arthroplasty (MTKA). Specifically, we compared: (1) index costs including computed tomography (CT) scans; (2) 90-day postoperative health care utilization, (3) 90-day episode-of-care (EOC) costs, and (4) lengths of stay between CT scan-based robotically-assisted versus MTKAs. A large national database, Blue Health Intelligence (BHI), was used for RATKAs and MTKAs performed between April 1, 2017 and September 30, 2019. Based on strict inclusion-exclusion criteria, with propensity score matching, 4,135 RATKAs and 4,135 MTKAs were identified and analyzed. Index costs to the payer for RATKA patients were found to be less than those for MTKA patients ($29,984 vs. $31,280, p <0.0001). Overall, 90-day EOC costs for RATKA patients were found to be less than that for MTKA patients in the inpatient and outpatient settings. This also holds true for the use of skilled nursing facilities, pharmacies, or other services. In conclusion, the results from our study show that RATKA were associated with lower costs than MTKAs, even when including the cost of CT scans. These results are of marked importance given the emphasis to contain and reduce health care costs.

Robotic-Arm Assisted Total Knee Arthroplasty: Cost Savings Demonstrated at One Year

Purpose

Robotic-arm assisted total knee arthroplasty (RATKA) has the potential to enhance radiographic, clinical, and patient-reported outcomes. The purpose of this study was to compare resource utilization, episode-of-care (EOC) costs, readmissions, and complications of robotic-arm assisted total knee arthroplasty (RATKA) and manual TKA (MTKA).

Methods

TKA procedures were identified from a private payer claims database. RATKA procedures required both a robotic arm-assisted procedure code and a 60-day pre-operative computed tomography scan. Propensity score matching (1:5 RATKA to MTKA) was performed, based on various patient characteristics and comorbidities. After matching, 4452 patients (742 RATKA and 3710 MTKA) were analyzed for 90-day and one-year EOC costs, index TKA costs, lengths of stay (LOS), discharge statuses, rehabilitation utilizations, as well as 90-day and one-year readmissions- and knee-related complications.

Results

RATKA patients had shorter LOS (mean 1.56 versus 1.91 days; p < 0.001), lower index costs by $1762 ($32,747 versus $34,509; p = 0.003), and higher discharges to home rates (51.8 versus 47.8%; p = 0.049) than MTKA patients. RATKA patients had less 90-day (68.5 versus 72.0%; p = 0.048) and one-year (70.8 versus 75.0%; p = 0.016) home health utilizations. The RATKA cohort had lower 90-day ($39,260 versus $41,458; p = 0.001) and one-year ($51,462 versus $54,171; p = 0.011) EOC costs. No significant differences in readmission and overall complication rates were observed (p > 0.05).

Conclusion

RATKA was associated with lower index costs and EOC costs at both 90 days and one year. These patients had shorter LOS, were discharged home more frequently, and used less home health services. Cost savings were demonstrated for RATKA beyond the 90-day period with an increase in savings between 90-day and one-year time points. These data may be of importance to payers and providers interested in the longer-term value of RATKA.

Robotic-arm assisted total knee arthroplasty is associated with improved accuracy and patient reported outcomes: a systematic review and meta-analysis

This systematic review and meta-analysis were conducted to compare the accuracy of component positioning, alignment and balancing techniques employed, patient-reported outcomes, and complications of robotic-arm assisted total knee arthroplasty (RATKA) with manual TKA (mTKA) and the associated learning curve. Searches of PubMed, Medline and Google Scholar were performed in October 2020 using PRISMA guidelines. Search terms included "robotic", "knee" and "arthroplasty". The criteria for inclusion were published clinical research articles reporting the learning curve for RATKA and those comparing the component position accuracy, alignment and balancing techniques, functional outcomes, or complications with mTKA. There were 198 articles identified, following full text screening, 16 studies satisfied the inclusion criteria and reported the learning curve of rTKA (n=5), component positioning accuracy (n=6), alignment and balancing techniques (n=7), functional outcomes (n=7), or complications (n=5). Two studies reported the learning curve using CUSUM analysis to establish an inflexion point for proficiency which ranged from 7 to 11 cases and there was no learning curve for component positioning accuracy. The meta-analysis showed a significantly lower difference between planned component position and implanted component position, and the spread was narrower for RATKA compared with the mTKA group (Femur coronal: mean 1.31, 95% confidence interval (CI) 1.08-1.55, p<0.00001; Tibia coronal: mean 1.56, 95% CI 1.32-1.81, p<0.00001). Three studies reported using different alignment and balancing techniques between mTKA and RATKA, two studies used the same for both group and two studies did not state the methods used in their RATKA groups. RATKA resulted in better Knee Society Score compared to mTKA in the short-to-mid-term follow up (95%CI [- 1.23,  - 0.51], p=0.004). There was no difference in arthrofibrosis, superficial and deep infection, wound dehiscence, or overall complication rates. RATKA demonstrated improved accuracy of component positioning and patient-reported outcomes. The learning curve of RATKA for operating time was between 7 and 11 cases. Future well-powered studies on RATKAs should report on the knee alignment and balancing techniques utilised to enable better comparisons on which techniques maximise patient outcomes.Level of evidence III.

Comparative Cost Analysis of Robotic-Assisted and Jig-Based Manual Primary Total Knee Arthroplasty

Excellent durability with traditional jig-based manual total knee arthroplasty (mTKA) has been noted, but substantial rates of dissatisfaction remain. Robotic-assisted TKA (raTKA) was introduced to improve clinical outcomes, but associated costs have not been well studied. The purpose of our study is to compare 90-day episode-of-care (EOC) costs for mTKA and raTKA. A retrospective review of an institutional database from 4/2015 to 9/2017 identified consecutive mTKAs and raTKAs using a single implant system performed by one surgeon. The raTKA platform became available at our institution in October 2016. Prior to this date, all TKAs were performed with mTKA technique. After this date, all TKAs were performed using robotic-assistance without exception. Sequential cases were included for both mTKA and raTKA with no patients excluded. Clinical and financial data were obtained from medical and billing records. Ninety-day EOC costs were compared. Statistical analysis was performed by departmental statistician. One hundred and thirty nine mTKAs and 147 raTKAs were identified. No significant differences in patient characteristics were noted. Total intraoperative costs were higher ($10,295.17 vs. 9,998.78, respectively, p < 0.001) and inpatient costs were lower ($3,893.90 vs. 5,587.40, respectively, p < 0.001) comparing raTKA and mTKA. Length of stay (LOS) was reduced 25% (1.2 vs. 1.6 days, respectively, p < 0.0001) and prescribed opioids were reduced 57% (984.2 versus 2240.4 morphine milligram equivalents, respectively, p < 0.0001) comparing raTKA with mTKA. Ninety-day EOC costs were $2,090.70 lower for raTKA compared with mTKA ($15,629.94 vs. 17,720.64, respectively; p < 0.001). The higher intraoperative costs associated with raTKA were offset by greater savings in postoperative costs for the 90-day EOC compared with mTKA. Higher intraoperative costs were driven by the cost of the robot, maintenance fees, and robot-specific disposables. Cost savings with raTKA were primarily driven by reduced instrument pan reprocessing fees, shorter LOS, and reduced prescribed opioids compared with mTKA technique. raTKA demonstrated improved value compared with mTKA based on significantly lower average 90-day EOC costs and superior quality exemplified by reduced LOS, less postoperative opioid requirements, and reduced postdischarge resource utilization.

Total Knee Arthroplasty Hospital Costs by Time-Driven Activity-Based Costing: Robotic vs Conventional

Background

Total knee arthroplasty (TKA) represents a major national health expenditure. The last decade has seen a surge in robotic-assisted TKA (roTKA); however, literature on the costs of roTKA as compared to conventional TKA (cTKA) is limited. The purpose of this study was to assess the costs associated with roTKA as compared to cTKA.

Methods

This was a retrospective cohort cost-analysis study of patients undergoing primary, elective roTKA or cTKA from July 2020 to March 2021. Time-driven activity-based costing (TDABC) was used to determine granular costs. Patient demographics, medical/surgical details, and costs were compared.

Results

A total of 2058 TKAs were analyzed (1795 cTKAs and 263 roTKAs). roTKA patients were more often male (50.2% vs 42.3%; P = .016), and discharged home (98.5% vs 93.7%; P = .017), and had longer operating room (OR) time (144.6 vs 130.9 minutes; P < .0001), and lower length of stay (LOS) (1.8 vs 2.1 days; P < .0001). roTKA costs were 2.17× greater for supplies excluding implant (P < .0001), 1.18× for total supplies (P < .0001), 1.12× for OR personnel (P < .0001), and 1.05× for total personnel (P = .0001). Implant costs were similar (P = .076), but 0.98× cheaper for post-anesthesia care unit personnel (P = .018) and 0.84× for inpatient personnel (P < .0001). Overall hospital costs for roTKA were 1.10× more than cTKA (P < .0001).

Conclusion

roTKA had higher total hospital costs than cTKA. Despite a lower LOS, the longer OR time with higher supply and personnel costs resulted in a costlier procedure. Understanding the costs of roTKA is essential when considering the value (ie, outcomes per dollars spent) of this modern technology.

The MAKO robotic-arm knee arthroplasty system

INTRODUCTION

The Mako robotic arm knee arthroplasty system was initially indicated in unicompartmental knee arthroplasty followed by bicompartmental and total knee arthroplasty techniques. The system utilizes three elements: (1) Pre-op 3D CT based planning and image based intra-op navigation. (2) Pre-resection implant modifications with integrated alignment, implant position and gap data, and (3) A semi-constrained robotic arm assisted execution of bone resection with "haptic" boundaries, and cemented implants.

MATERIALS AND METHODS

This paper evaluates variable pre-op implant placement, and anatomic reference positioning; data entry with incorporation of alignment, implant congruency through range of motion, and gaps; bone resection with "haptic" boundaries, and final implant evaluation with kinetic sensors.

RESULTS

The Mako system allowed for improved implant placement utilizing CT guidance, bone resection accuracy, flexibility for functional implant placement with gap balancing. When combined with kinetic sensors, there was improved rotation and soft tissue balance.

CONCLUSION

The MAKO robotic system can assist the surgeon with anatomic landmarks, provides the flexibility for independent gap balance through implant and alignment refinement, and three-dimensional soft tissue balancing data to achieve functional stability. Registry data has shown improved outcome survivorship irrespective of the surgeons' volumes and learning curves.

MAKO CT-based robotic arm-assisted system is a reliable procedure for total knee arthroplasty: a systematic review

PURPOSE

The aim of this study was to investigate the clinical and radiological results of the MAKO CT-based robotic-assisted system for total knee arthroplasty (TKA).

METHODS

A PRISMA systematic review was conducted using four databases (MEDLINE, EMBASE, Pubmed, GOOGLE SCHOLAR) to identify all clinical and radiological studies reporting information regarding the use and results of the CT-based robotic-assisted system to perform TKA between 2016 and 2020. The main investigated outcome criteria were postoperative pain, analgesia requirements, clinical scores, knee range of motion, implant positioning and the revision rate. The ROBINS-I tool (Risk Of Bias In Non-randomized Studies of Interventions) was used to evaluate the quality of included studies and the risk of bias.

RESULTS

A total of 36 studies were identified, of which 26 met inclusion criteria. Of these 26 studies, 14 were comparative. The follow-up varied from 30 days to 17 months. This CT-based, saw cutting Robotic TKA is associated with a significantly lower postoperative pain score (2.6 versus 4.5) and with significantly reduced time to hospital discharge (77 h versus 105), compared with conventional TKA. The two comparative studies assessing functional outcomes at 1 year reported significantly better functional scores with CT-based robotic TKA compared with conventional TKA (WOMAC score: 6 ± 6 versus 9 ± 8 (p < 0.05); KSS function score: 80 versus 73 (p = 0.005)). Only three comparative studies assessed implant positioning, and these reported better implant positioning with CT-based robotic-assisted TKA.

CONCLUSION

The CT-based robotic-assisted system for TKA reduced postoperative pain and improved implant positioning with equal or slightly superior improvement of the functional outcomes at one year, compared to conventional TKA.

LEVEL OF EVIDENCE

Systematic review level IV.

Nursing considerations for patients undergoing robotic-arm assisted joint replacements

Robotic-arm assisted arthroplasty (RAA) has gained popularity over the past decade because of its ability to provide more accurate implant positioning with less surgical trauma than conventional manual arthroplasty. It has shown better early functional outcomes, less postoperative pain and shorter inpatient stays. A multidisciplinary approach is crucial in improving overall outcomes and ensuring this technology is implemented efficiently and safely, but there is limited published literature on the nursing considerations for managing patients undergoing RAA. This article aims to provide a pragmatic approach for nursing care in the pre-, intra-, and postoperative phases of RAA.

Clinical outcomes associated with robotic and computer-navigated total knee arthroplasty: a machine learning-augmented systematic review

BACKGROUND

Robotic (RTKA) and computer-navigated total knee arthroplasty (CNTKA) are increasingly replacing manual techniques in orthopaedic surgery. This systematic review compared clinical outcomes associated with RTKA and CNTKA and investigated the utility of natural language processing (NLP) for the literature synthesis.

METHODS

A comprehensive search strategy was implemented. Results of included studies were combined and analysed. A transfer learning approach was applied to train deep NLP classifiers (BERT, RoBERTa and XLNet), with cross-validation, to partially automate the systematic review process.

RESULTS

52 studies were included, comprising 5,067 RTKA and 2,108 CNTKA. Complication rates were 0-22% and 0-16% and surgical time was 70-116 and 77-102 min for RTKA and CNTKA, respectively. Technical failures were more commonly associated with RTKA (8%) than CNTKA (2-4%). Patient satisfaction was equivalent (94%). RTKA was associated with a higher likelihood of achieving target alignment, less femoral notching, shorter operative time and shorter length of stay. NLP models demonstrated moderate performance (AUC = 0.65-0.68).

CONCLUSIONS

RTKA and CNTKA appear to be associated with similarly positive clinical outcomes. Further work is required to determine whether the two techniques differ significantly with regard to specific outcome measures. NLP shows promise for facilitating the systematic review process.

Can robotic technology mitigate the learning curve of total hip arthroplasty?

Aims

Traditionally, acetabular component insertion during total hip arthroplasty (THA) is visually assisted in the posterior approach and fluoroscopically assisted in the anterior approach. The present study examined the accuracy of a new surgeon during anterior (NSA) and posterior (NSP) THA using robotic arm-assisted technology compared to two experienced surgeons using traditional methods.

Methods

Prospectively collected data was reviewed for 120 patients at two institutions. Data were collected on the first 30 anterior approach and the first 30 posterior approach surgeries performed by a newly graduated arthroplasty surgeon (all using robotic arm-assisted technology) and was compared to standard THA by an experienced anterior (SSA) and posterior surgeon (SSP). Acetabular component inclination, version, and leg length were calculated postoperatively and differences calculated based on postoperative film measurement.

Results

Demographic data were similar between groups with the exception of BMI being lower in the NSA group (27.98 vs 25.2; p = 0.005). Operating time and total time in operating room (TTOR) was lower in the SSA (p < 0.001) and TTOR was higher in the NSP group (p = 0.014). Planned versus postoperative leg length discrepancy were similar among both anterior and posterior surgeries (p > 0.104). Planned versus postoperative abduction and anteversion were similar among the NSA and SSA (p > 0.425), whereas planned versus postoperative abduction and anteversion were lower in the NSP (p < 0.001). Outliers > 10 mm from planned leg length were present in one case of the SSP and NSP, with none in the anterior groups. There were no outliers > 10° in anterior or posterior for abduction in all surgeons. The SSP had six outliers > 10° in anteversion while the NSP had none (p = 0.004); the SSA had no outliers for anteversion while the NSA had one (p = 0.500).

Conclusion

Robotic arm-assisted technology allowed a newly trained surgeon to produce similarly accurate results and outcomes as experienced surgeons in anterior and posterior hip arthroplasty.

Cite this article: Bone Jt Open 2021;2(6):365–370.

The current state of robotics in total knee arthroplasty

Robotic total knee arthroplasty (TKA) has demonstrated improved component positioning and a reduction of alignment outliers with regard to pre-operative planning.

Early robotic TKA technologies were mainly active systems associated with significant technical and surgical complications.

Current robotic TKA systems are predominantly semi-active with additional haptic feedback which minimizes iatrogenic soft tissue injury compared to conventional arthroplasty and older systems.

Semi-active systems demonstrate advantages in terms of early functional recovery and hospital discharge compared to conventional arthroplasty.

Limitations with current robotic technology include high upfront costs, learning curves and lack of long-term outcomes.

The short-term gains and greater technical reliability associated with current systems may justify the ongoing investment in robotic technology.

Further long-term data are required to fully ascertain the cost-effectiveness of newer robotic systems.

Cite this article: EFORT Open Rev 2021;6:270-279. DOI: 10.1302/2058-5241.6.200052

Expanding Robotic Arm-Assisted Knee Surgery: The First Attempt to Use the System for Knee Revision Arthroplasty

Robotic arm-assisted arthroplasty was introduced in 2006 and has expanded its applications into unicompartmental knee, total knee, and total hip replacement. The first case of a revision surgery from conventional unicompartmental to total knee arthroplasty with the utilization of the robotic arm-assisted MAKO system is presented. An 87-year-old female presented with deteriorating left knee pain due to failure of medial unicompartmental knee arthroplasty at the outpatient clinic. The patient was advised to undergo revision surgery. Through medial parapatellar arthrotomy, the joint was exposed. With the use of the MAKO system, the estimated depth of the medial plateau according to CT planning was found to be 10 mm more distal than the lateral. The resection line of the remaining plateau was placed deliberately 2 mm more distal in order to achieve satisfactory replacement of the bony gap of the medial tibial condyle by a 10 mm augment. The patient had an uneventful recovery. A plethora of additional applications in the future, such as total shoulder or reverse total shoulder arthroplasty, megaprosthesis placement in oncological patients, and total hip or knee revision surgeries, may improve patient-related outcomes.