Robot-Assisted Unicompartmental Knee Arthroplasty: Increasing Surgical Accuracy? A Cadaveric Study

Learning curve of Persona Partial Knee (PPK) arthroplasty: a clinical trial

BACKGROUND

Unicompartmental knee arthroplasty (UKA) procedures are considered to be more technically demanding than conventional total knee arthroplasty (TKA), requiring a longer learning curve and more expert surgical skills. Despite some clear advantages of UKA over TKA (such as lesser blood loss, greater bone stock, greater knee performances, etc.), UKA evidenced a greater rate of revision.

OBJECT

This study investigated the learning curve of Persona Partial Knee (PPK) arthroplasty for primary medial UKA performed by a single, non-designer surgeon. PPK is a fixed-bearing, compartment-specific implant. The primary outcome of interest for this study was to evaluate the learning curve of the surgical duration. The secondary outcome of interest was to evaluate the learning curve of radiological implant positioning.

METHODS

Patients who underwent primary medial UKA using PPK (Zimmer-Biomet, Warsaw IN, USA) were prospectively enrolled for the study. All surgeries were performed by a single, non-designer surgeon experienced in knee and hip arthroplasty. The primary outcome of interest was to evaluate the surgical duration. The secondary outcome of interest was to evaluate the implant positioning. The learning curve was estimated using an appropriate nonlinear polynomial regression model with a lower Akaike Information Criterion (AIC).

RESULTS

One hundred twenty five patients were enrolled in the study. 59% of them (74 of 125 patients) were women. The patients' mean age at the time of surgery was 70.1 ± 9.5 years and their mean body mass index (BMI) was 27.8 ± 4.2 kg/m2. Curve stabilisation of the surgical time was at the 94th patient, of the tibial angle at the 47th patient, of the tibial slope at the 54th patient, of the anterior protrusion at the 29th patient, and of the posterior protrusion at the 51st patient.

CONCLUSIONS

The learning curve for component positioning was achieved in approximately 50 cases. The curve of the surgical time achieved a plateau at 94 Persona Partial Knee. Additionally, the factors directly correlated with earlier stabilization of the learning curve in terms of component positioning were: male gender, younger age, right side, and larger components.

Does robotic-assisted unicompartmental knee arthroplasty restore native joint line more accurately than with conventional instruments?

The study's primary aim is the restoration of native joint line in patients having robotic-assisted unicondylar knee arthroplasty and conventional unicondylar knee arthroplasty. Literature in the past has demonstrated that reducing the joint line can result in greater failure rates. This is a prospective cohort investigation of patients who had medial UKA between March 2017 and March 2022.All patient's pre-operative and post-operative radiological joint line assessments were examined by two observers by Weber's methods. Robotic-assisted UKA performed with hand-held image-free robots was compared to conventional UKA groups. The distal position of the femoral component was higher in Group B utilizing conventional tools than in Group A employing robotic-assisted UKA. This positional difference was statistically significant. The mean difference among the pre-operative and post-operative joint lines in Group A was 1.6 ± 0.49 (range 0.8 mm-2.4 mm), while it was 2.47 ± 0.51 (range 1.6 mm-3.9 mm) (p 0.005) in Group B. In Group A, a greater percentage of the subjects (64%) attained a femoral component position within two millimeters from the joint line, whereas just 18% in Group B did. When compared with the conventional UKA technique, the meticulous attention to detail and planning for ligament rebalancing when using the robotic-assisted UKA technique not solely enhance surgical precision for implant placing but additionally provides excellent native joint line restoration and balancing. For validation of its longevity and survivability, the cohort must be tracked for a longer period of time.

Robotic-assisted foot and ankle surgery: a review of the present status and the future

The surgical application of robotics has increased significantly since its first application in 1985 for a brain biopsy acquisition. Robotic-assisted surgery has been one of the viable options in various surgical areas, and also in orthopaedic surgery. Robotic-assisted orthopaedic surgery has gained popularity as a mean of improving accuracy, reducing complications and achieving better patient satisfaction. Numerous clinical research studies have demonstrated advantages of robotic-assisted orthopaedic surgery, however, most of that researches were about the total knee arthroplasty, total hip arthroplasty and spine surgery. The application of robotic technology in foot and ankle surgery is in a very nascent stage. Furthermore, there has been little research on intraoperative use of robotics in foot and ankle surgery in literature. A review of previous preclinical studies in foot and ankle robotics and clinical research studies in various fields of robot-assisted orthopaedic surgery shows that its potential application and benefits over conventional techniques, such as total ankle arthroplasty, minimally invasive surgery for foot and ankle trauma or other corrective procedure, and intraoperative biomechanical testing. More studies on practical application of robotic technology to surgical procedure in the field of foot and ankle surgery are needed to confirm its clinical usefulness and cost effectiveness.

Robotic Versus Conventional Unicompartmental Knee Surgery: A Comprehensive Systematic Review and Meta-Analysis

Robotic-assisted surgery is a computer-controlled technique that may improve the accuracy and outcomes of unicompartmental total knee arthroplasty (TKA), a partial knee replacement surgery. The purpose of a meta-analysis about robotic-assisted versus conventional surgery for unicompartmental TKA is to compare the effectiveness of these two methods based on the current evidence. Our meta-analysis can help inform clinical decisions and guidelines for surgeons and patients who are considering unicompartmental TKA as a treatment option. We searched four online databases for studies that compared the two methods until March 2023. We used RevMan software to combine the data from the studies. We calculated the mean difference (MD) and the 95% confidence interval (CI) for each outcome, which are statistical measures of the difference and the uncertainty between the two methods. We included 16 studies in our analysis. We found that robotic-assisted surgery had a better hip-knee-ankle angle, which is a measure of how well the knee is aligned, than conventional surgery (MD = 0.86, 95% CI = 0.16-1.56). We also found that robotic-assisted surgery had a better Oxford Knee score, which is a measure of how well the knee functions, than conventional surgery (MD = 3.03, 95% CI = 0.96-5.110). This study compared the results of conventional and robotic-assisted unicompartmental knee arthroplasty in 12 studies. We concluded that robotic-assisted surgery may have some benefits over conventional surgery in terms of alignment and function of the knee. However, we did not find any significant difference between the two methods in terms of other outcomes, such as pain, range of motion, health status, and joint awareness. Therefore, we suggest that more research is needed to confirm these results and evaluate the long-term effects and cost-effectiveness of robotic-assisted surgery.

The Impact of Surgeon Variability on Patient-Reported Outcome Measures, Length of Stay, Discharge Disposition, and 90-Day Readmission in TKA

BACKGROUND

Studies involving total knee arthroplasty (TKA) have focused on patient-related factors as drivers of outcomes. Although some studies have investigated surgeon and/or surgery-level factors (i.e., approach, volume), the measure of variance in postoperative outcomes across surgeons following TKA has not been determined. The aim of the current study was to evaluate the relationship between the surgeon and 1-year patient-reported outcome measures, the length of stay, the discharge disposition, and 90-day readmission after TKA, as well as the differences in these variables among surgeons.

METHODS

Data were prospectively collected for 5,429 patients who underwent TKA at a large health-care system with 36 surgeons between 2016 and 2018. Likelihood ratio tests were performed to investigate the relationship between surgeon and the 1-year Knee injury and Osteoarthritis Outcome Score (KOOS)-Pain subscale, KOOS-Physical Function Shortform (KOOS-PS), KOOS for Joint Replacement (KOOS-JR), patient acceptable symptom state (PASS), length of stay, discharge disposition, and 90-day readmission. The minimal clinically important difference (MCID) was used to assess meaningful outcomes. Variable importance was determined by the Akaike information criterion (AIC) increase, using ordinal and binary-response mixed-effect models.

RESULTS

There was a significant association between surgeon and KOOS-Pain (p < 0.001), KOOS-PS (p = 0.001), KOOS-JR (p < 0.001), PASS (p = 0.024), length of stay (p < 0.001), discharge disposition (p < 0.001), and 90-day readmission (p < 0.001). When modeling 1-year KOOS-Pain (AIC increase, 15.6), KOOS-PS (AIC increase, 6.8), KOOS-JR (AIC increase, 13.5), PASS (AIC increase, 1.9), length of stay, and discharge disposition, the surgeon variable contributed more to the 1-year outcome than some patient-level factors (e.g., body mass index, Charlson Comorbidity Index). The difference between the highest and lowest median probabilities of attaining the same value for the KOOS-Pain (11.2%), KOOS-PS (9.4%), KOOS-JR (11.8%), PASS (5.9%), length of stay (46.6%), discharge disposition (22.8%), and readmission (13.1%) indicated surgeon-level variability.

CONCLUSIONS

Surgeon-related factors may be stronger contributors to the 1-year patient-reported outcome measures and length of stay than patient characteristics emphasized in the literature. Current findings have suggested variability in patient-reported outcome measures, length of stay, discharge location, and 90-day readmission among surgeons. Surgeon variability should be considered when model-fitting in the setting of TKA.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Arthroscopic-assisted robotic bi-unicompartmental knee arthroplasty: a pilot cadaveric study

INTRODUCTION

Although bicondylar arthroplasty showed great functional results, it encounters some difficulties to be performed routinely. On the other hand, arthroscopic techniques tend to replace open surgical techniques in sports medicine but strive to be developed in the field of arthroplasty. This study aimed to assess the feasibility of a micro-invasive bi-compartmental knee arthroplasty using both arthroscopic and robotic technologies (A-BiUKA).

MATERIALS AND METHODS

The study was conducted on complete fresh-frozen and embalmed cadaveric specimens. The main criterion of judgment was the successful positioning of trial implants through a minimal quad-sparing approach. Arthroscopy was used for bone-morphing and burring, supported by an image-free robotic system. Secondary criteria of judgment were axial deviation (measured using the navigation system), operating time, and incision length.

RESULTS

Ten A-BiUKA were performed. Implantation was successful in all cases. The mean preoperative frontal deviation was 179.8° ± 3.2 [175: 185], the mean postoperative frontal deviation was 178.5° ± 2.2 [175: 182], without any outliers. The mean correction was 1.7° ± 1.6 [0: 5]. Once the eight first A-UKA were performed, constituting the learning curve, the mean operative time for the remaining twelves surgeries was 90 min ± 6. The mean skin incision length was 3.35 cm ± 0.13 [3: 4].

CONCLUSION

Associated arthroscopic and robotic technologies allows to perform Bi-UKA procedure using a quad sparing mini-invasive approach. Clinical prospective studies have to confirm the feasibility and the clinical outcomes of this surgery.

[Market overview: Robotic-assisted arthroplasty : Current robotic systems, learning curve and cost analysis]

Robotic-assisted arthroplasty has been rapidly entering clinical routine in recent years. The leading endoprosthesis manufacturers have all meanwhile placed robotic systems on the market, which, however, differ significantly from one another technically. Current systems are currently classified according to the degree of autonomy (active vs. semi-active vs. passive) and the data/image source (image-based: CT vs. X‑ray, imageless). Some systems already offer the possibility of robotic-assisted or navigated implantation of hip endoprostheses. In the following review article, the currently leading robotic systems will be presented and compared with regard to their characteristics. Furthermore, the analysis of the learning curves for the different systems, currently available cost analysis models and an outlook on future developments and challenges will be given.

Navigation und Robotik in der Knieendoprothetik

Hintergrund

Die Langlebigkeit einer Knieprothese hängt von der korrekten Ausrichtung der Prothesenkomponenten und der mechanischen Achse des Beins sowie einer optimalen Weichteilbalancierung ab. Um dieses Ziel präziser und sicherer zu erreichen, wurde die computerassistierte Chirurgie entwickelt. Ziel dieses Artikels ist es, die Navigation und Robotik zu bewerten und die aktuellen Ergebnisse zu diskutieren.

Methode

Umfassende Literaturrecherche in der Datenbank PubMed und dem Suchdienst Google Scholar.

Ergebnisse

Die computerassistierte Chirurgie führt zu einer präziseren Ausrichtung der mechanischen Beinachse und der Positionierung der Prothesenkomponenten. Trotzdem sind die klinischen Ergebnisse zur Kniefunktion und die Resultate der patientenbezogenen Fragebögen (PROMs) kontrovers. Sie zeigen, wie für die Überlebensrate, keinen signifikanten Unterschied zur konventionellen Technik. Hohe Anschaffungs- und Unterhaltskosten limitieren zudem die Verbreitung dieser Systeme.

Schlussfolgerung

Momentan bietet die bildgestützte Navigation dem Chirurgen bei gewissen Operationsschritten eine wertvolle Unterstützung für ein präziseres und sichereres Arbeiten. Trotzdem sind Langzeitstudien zur Kniefunktion, zu den PROMs, zur Überlebensrate dringend erforderlich. In der Robotik zeigen nur kurzfristige Ergebnisse ähnliche Trends wie bei der Navigation. Die Robotiksysteme müssen und werden sich weiterentwickeln, um den Anforderungen der Nutzer und Patienten zu entsprechen (Kosten, Größe, Programmierung).

What is the evidence for clinical use of advanced technology in unicompartmental knee arthroplasty?

BACKGROUND

With an aim of improving prosthesis survivorship of unicompartmental knee arthroplasty (UKA), use of computer-assisted technologies (CATs) such as robotics, has been on the rise to reduce intraoperative errors in surgical technique. In light of recent influx of CATs in the UKA, a review of these innovations will help providers to understand their clinical utility.

METHOD

A systematic literature search was performed following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.

RESULTS

Among 19 studies comparing robot-assisted UKA with conventional UKA, only 32% were randomized control trials, 47% reported minimum mean follow-up of 2 years, and 21% evaluated prosthesis survival. Similar results were obtained for navigation-assisted UKA and UKA performed with patient-specific instrumentation.

CONCLUSION

While CATs seem to reduce the surgical errors in UKA, the evidence on the efficacy of any of the studied CATs to improve survivorship remains limited and there are issues related to cost-effectiveness, learning curve, and increase in operating time.

Robotic-assisted unicompartmental knee arthroplasty: a review

Purpose

Presented here is an up-to-date review concerning robotic-assisted unicompartmental knee arthroplasty (rUKA), including its rationale, operative system, pros and cons.

Methods

We did a systematic research in electronic databases, including PubMed, Cochrane Library, Web of Science, and Embase up to March 30, 2020 to retrieve literature pertaining to rUKA. The search strategies “(robotic* AND knee arthroplasty OR knee replacement)” and “(knee arthroplasty OR knee replacement NOT total)” were used. Studies describing rUKA and clinical trials, dry bone or cadaveric researches regarding technologies, positioning, alignment, function, or survivorship of implants were included in this review. All retrieved studies were first browsed for eligibility on the basis of title and abstract, and the selected studies were further evaluated by reading full text for final inclusion.

Results

Robotic-assisted technology has been found to increase the accuracy of bone preparation and implant placement, reduce technical variability and outliers, and enhance reproduction of limb alignment. Additionally, early clinical outcomes were excellent, but mid-term follow-up showed no superiority in component survivorship. The potential drawbacks of the robotic-assisted technology include relatively-low time- and cost-effectiveness, development of some rUKA-related complications, and lack of support by high-quality literature.

Conclusion

This review shows that rUKA can decrease the number of outliers concerning the optimal implant positioning and limb alignment. However, due to absence of extensive studies on clinical outcomes and long-term results, it remains unclear whether the improved component positioning translates to better clinical outcomes or long-term survivorship of the implant. Nevertheless, since an accurate implant position is presumably beneficial, robotic-assisted technology is worth recommendation in UKA.

Robotic-assisted vs conventional surgery in medial unicompartmental knee arthroplasty: a clinical and radiological study

BACKGROUND

The use of unicompartmental knee arthroplasty (UKA) has increased and new technologies have been developed to improve patient survival and satisfaction, soft tissue balance, alignment, and component size. Robot-assisted systems offer an increase in surgical precision and accuracy. The purpose of this study is to evaluate the precision of component position using five radiological parameters in conventional and robotic-assisted medial UKA using the NAVIO system.

METHODS

A cohort study was designed for patients who underwent medial UKA between April 2017 and March 2019 in a single center. Patients were allocated in the conventional (UKA-C) or robotic-assisted (UKA-R) group. The variables analyzed were age, gender, affected knee side, length of hospital stay, surgical time, and radiological measurements such as anatomical medial distal femoral angle (aMDFA), anatomical medial proximal tibial angle (aMPTA), tibial slope, the sagittal femoral angle, and the component size. A target was defined for each measurement, and a successful UKA was defined if at least four radiological measures were on target after surgery. Also, patients' reported outcomes were evaluated using the Oxford Knee Score (OKS) and a numeric rating scale (NRS) for pain.

RESULTS

Thirty-four patients were included, 18 of them underwent UKA-R. The success rate for UKA in the UKA-R group was 87%; meanwhile, in the UKA-C group this was 28%, this difference was significant and powered (Fisher's exact test, p = 0.001; 1 - β = 0.95). Also, a 5-point difference in favor of the UKA-R group in the median OKS (p = 0.01), and a significantly lower median NRS for pain (p < 0.000) were found after surgery.

CONCLUSIONS

UKA-R achieved more precision in the radiological parameters' measure in this study. Also, UKA-R has a trend towards a better OKS and a lower NRS for pain at short-term follow-up.

Robotic-assisted Unicompartmental knee Arthroplasty optimizes joint line restitution better than conventional surgery

Purpose

To compare joint line restoration after unicompartmental knee arthroplasty (UKA) between conventional and robotic-assisted surgery. Previous studies have shown that joint line distalization can lead to higher failure rates. The hypothesis was that robotic-assisted UKA is associated with less femoral component distalization and a precise tibial cut, which allows a more anatomical restitution of the knee joint line.

Methods

Retrospective cohort study of patients undergoing medial or lateral UKA between May 2018 and March 2020. Preoperative and postoperative radiologic assessment of the joint line was performed by two observers, using three different methods, one for tibial slope and one for tibial resection. Robotic assisted UKA and conventional UKA groups were compared.

Results

Sixty UKA were included, of which 48 (77.42%) were medial. Robotic-assisted UKA were 40 (64.52%) and 22(35.48%) were conventional

The distalization of the femoral component was higher in the conventional group despite the method of measurement used In both Weber methods, the difference was statistically different: Conventional 2.3 (0.9 to 5.6) v/s Robotic 1.5 (− 1.1 to 4.1) (p =0.0025*). A higher proportion of patients achieved a femoral component position ≤ two millimeters from the joint line using robotic-assisted UKA compared to the conventional technique .

No statistical difference between robotic-assisted and conventional UKA was found in tibial resection and slope.

Conclusion

Robotic-assisted UKA shows a better rate of joint line restoration due to less femoral component distalization than conventional UKA. No difference was found in the amount of tibial resection between groups in this study.

Level of evidence

III

Robotic-assisted surgery in medial unicompartmental knee arthroplasty: does it improve the precision of the surgery and its clinical outcomes? Systematic review

There is a high prevalence of knee osteoarthritis that affects only the medial tibiofemoral compartment. In this group of patients with severe disease, the medial unicompartmental knee arthroplasty (UKA) is an excellent choice. However, this technique has a great learning curve due to the lower tolerance of improper positioning and alignment. In this context, the robotic-assisted surgery (RAS) arises as an option to improve the accuracy and secondarily enhance the clinical outcomes related to the UKA. The objective in this study is to determine if there are significant advantages with the use of RAS over conventional surgery (CS). In the systematic review of the literature, classification of the results in three main subjects: (A) precision and alignment; (B) functional results and clinical parameters; (C) survivorship. We found 272 studies, of which 15 meet the inclusion and exclusion criteria. There is mostly described that RAS significantly improves the accuracy in position (80-100% of planned versus performed P < 0.05), alignment (2-3 times less error variance P < 0.05) and selection of the proper size of the implants (69.23% of correct size femoral implants versus 16.67% using CS P < 0.0154). Recently, there is mild evidence about benefits in the early rehabilitation and post-operative pain, but in all studies reviewed, there is no advantages of RAS in the long-term functional evaluation. There is no strong literature that supports a longer survival of the prothesis with RAS, being the longest mean follow-up reported of 29.6 months. RAS is a useful tool in increasing the precision of the medial UKA implant placement. However, there is still a lack of evidence that properly correlates this improvement in accuracy with better clinical, functional and survival results.

Global research status and trends of UKA for knee osteoarthritis: a bibliometric analysis

Objective

As an alternative of knee-protection surgery, unicompartmental knee arthroplasty has been widely used for the treatment of knee osteoarthritis and has achieved good clinical results. However, reports on its data and trend are scanty. This article reviewed current status and trend in the research of UKA, and compared different regions, organizations and authors in terms of their contributions to the field.

Methods

The literature on UKA ranging from 2009 to 2019 was searched in the “Web of Science” database, and the search results were visually presented by using Excel and VOS-viewer software packages, and the status quo and development trends of relevant studies were analyzed.

Results

A total of 1264 articles on UKA were identified, of which 330 were the larger studies conducted in the United States. The institution that published most papers was Oxford University, with a total of 109 papers published. MURRAY DW was the largest contributor in this field. The National Institutes of Health was the largest funding agencies of the UKA. Studies could be divided into six clusters in terms of prosthesis design, follow-up investigation, OA etiology, hip-knee association, joint replacement registration, and computer navigation. “Computer-aided navigation” and “gait analysis” promise to be future hot spots in the field of UKA research.

Conclusion

Global trend analysis suggests that UKA research is gradually deepening and the number of papers has been on the rise. The USA was the largest contributor to this field. More research effort should be directed to “Computer-aided navigation”and “gait analysis”, which might be the popular topics in the UKA field in not very distant future.

Robotic technology: current concepts, operative techniques and emerging uses in unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) is associated with improved functional outcomes but reduced implant survivorship compared to total knee arthroplasty (TKA).

Surgeon-controlled errors in component positioning are the most common reason for implant failure in UKA, and low UKA case-volume is associated with poor implant survivorship and earlier time to revision surgery.

Robotic UKA is associated with improved accuracy of achieving the planned femoral and tibial component positioning compared to conventional manual UKA.

Robotic UKA has a learning curve of six operative cases for achieving operative times and surgical team comfort levels comparable to conventional manual UKA, but there is no learning curve effect for accuracy of implant positioning or limb alignment.

Robotic UKA is associated with reduced postoperative pain, decreased opiate analgesia requirements, faster inpatient rehabilitation, and earlier time to hospital discharge compared to conventional manual UKA.

Limitations of robotic UKA include high installation costs, additional radiation exposure with image-based systems, and paucity of studies showing any long-term differences in functional outcomes or implant survivorship compared to conventional manual UKA.

Further clinical studies are required to establish how statistical differences in accuracy of implant positioning between conventional manual UKA and robotic UKA translate to long-term differences in functional outcomes, implant survivorship, complications, and cost-effectiveness.

Cite this article: EFORT Open Rev 2020;5:312-318. DOI: 10.1302/2058-5241.5.190089