Comparative analysis of revision causes between robotic-assisted and conventional manual unicompartmental knee arthroplasty: a systematic review and meta-analysis.

Unicompartmental knee arthroplasty (UKA) has significant advantages over total knee arthroplasty (TKA). However, due to its need for precise positioning and soft tissue balancing, UKA failures and revision rates may be higher than that of TKA. Robotic-assisted UKA offers more accurate implant positioning, soft tissue balancing, improved lower limb alignment, and a reduction in surgical error. There are few studies studying functional outcomes post robotic-assisted UKA. The aim of this study was to compare the functional outcomes between robotic-assisted and conventional medial UKA. A retrospective review was done of 159 patients; 110 patients underwent conventional UKA while 49 patients underwent robotic-assisted UKA. Outcome measures included the Oxford Knee Score (OKS), Knee Society Score (KSS), Visual Analogue Score (VAS) for pain, and range of motion (ROM) at three months, one-year and two years post-UKA. Pre-operative patient demographics and outcome scores were not significantly different between both groups. ROM was significantly greater in the MAKO compared to the Oxford group at 3 months (p=0.039), 1 year (0.053) and 2 years (0.001) post-operation. While OKS, KSS and VAS scores improved for both groups, there were no significant differences in the final outcome measures. None of the patients experienced a mechanical failure, infection, or revision post-surgery. One patient each in the Oxford and MAKO group suffered a periprosthetic fracture. Both robotic-assisted MAKO UKA and conventional Oxford UKA showed good clinical outcomes. Robotic-assisted MAKO UKA had superior ROM outcomes compared to conventional Oxford UKA up to two years post-surgery.

Update This article was updated on February 6, 2019, because of a previous error. On page 105, in the subsection titled “Outcomes and Design” the sentence that had read “Furthermore, in a retrospective review, Houdek et al. 48 , at a mean follow-up of 8 years, demonstrated improved survivorship of 9,999 metal-backed compared with 1,645 all-polyethylene tibial components, over all age groups and most BMI categories” now reads “Furthermore, in a retrospective review, Houdek et al. 48 , at a mean follow-up of 8 years, demonstrated inferior survivorship of 9,999 metal-backed compared with 1,645 all-polyethylene tibial components, over all age groups and most BMI categories.” An erratum has been published: J Bone Joint Surg Am. 2019 Mar 20;101(6):e26.

The study aims to provide an up-to-date systematic review and meta-analysis comparing radiological and functional outcomes of total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) using either robotic assistance or conventional methods from the latest assemblage of evidence. This study was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. All studies in PubMed, EMBASE, Medline, and Cochrane that reported radiological and functional outcomes after TKA or UKA with either robotic or conventional methods were included in the review. Selected endpoints for random effects, pairwise meta-analysis included operative details, radiological outcomes (mechanical axis, component angle deviation, and outliers), and functional outcomes (American Knee Society Score, Knee Society Function Score, revision and complication rate, range of motion (ROM), Hospital for Special Surgery score, and Western Ontario and McMaster Universities Osteoarthritis Index). A total of 23 studies comprising 2,765 knees were included from the initial search. Robot-assisted TKA and UKA were associated with significantly better component angle alignment accuracy (low-to-high quality evidence) at the cost of significantly greater operation time. Robot-assisted UKA was found to have significantly better short-term functional outcomes compared with conventional UKA (moderate-to-high quality evidence). Robot-assisted TKA, however, did not exhibit significantly better short- and midterm subjective knee outcome scores compared with its conventional counterpart (high-quality evidence). Robot-assisted TKA and UKA were associated with nonstatistically significant improved ROM and lesser rates of revision. Robot-assisted total and unicompartmental knee arthroplasty leads to better radiological outcomes, with no significant differences in mid- and long-term functional outcomes compared with conventional methods for the former. Larger prospective studies with mid- and long-term outcomes are required to further substantiate findings from the present study.

PurposeTo 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.MethodsRetrospective 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.ResultsSixty UKA were included, of which 48 (77.42%) were medial. Robotic-assisted UKA were 40 (64.52%) and 22(35.48%) were conventionalThe 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.ConclusionRobotic-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 evidenceIII

PurposeIt is known that in uni-compartmental knee arthroplasty (UKA) low-volume surgeons have a higher complication and revision rate than high-volume surgeons. Further, robotic-assisted UKA leads to lower early revision rate as well as fewer limb and joint line outliers compared to conventional UKA. The purpose of this study was to retrospectively analyze the outliers’ and revision rate of low-volume UKA surgeons with different robotic systems at short-term follow-up.MethodsIn this case–control study, 103 robotic-assisted UKAs were included. The procedures were performed between 2016 and 2019 from two low-volume UKA surgeons with an imageless (IL) (63 patients) and image-based (IB) (40 patients) robotic system. Alignment outliers, joint line (JL) reconstruction, complication and revision rates of the two different robotic systems were analyzed. The minimum follow-up was two years. Outliers were defined as a postoperative valgus malalignment greater than 182°. The surgery time for all procedures was evaluated.ResultsThe overall revision rate was 3.9% (4 of 103). Two occurred in the IB group (5.0%) and two in the IL group (3.2%). No valgus malalignment outliers were observed in both groups. The mean JL was not distalized by more than 2 mm in both groups (IL: 1.3 ± 1.6 mm vs. IB: 1.8 ± 0.9 mm, p value 0.08). The IL procedures had a significant lower mean surgery time (55 ± 13 min vs. 68 ± 14, p value 0.001).ConclusionRobotic-assisted UKA is a safe procedure in the hand of low-volume UKA surgeons. Robotic-assisted UKA minimizes overcorrection into valgus mal-alignment. Low revision rates are observed at short-term follow-up for robotic-assisted UKA. The choice of the different robotic systems has no impact on the outcome.

Background:Robotic arm-assisted unicompartmental knee arthroplasty (UKA) has been recommended for treatment of unicompartmental knee osteoarthritis. However, its effectiveness and safeness remain controversial compared with conventional UKA. Therefore, the goal of this study was to perform a meta-analysis to re-evaluate the effects of robotic arm-assisted UKA on clinical functional outcomes.Methods:PubMed, Embase, and Cochrane Library databases were searched to screen the relevant studies. Continuous data (surgical time, knee excursion during weight acceptance, American knee society score [AKSS], Oxford knee score [OKS], forgotten joint score [FJS], visual analog scale [VAS], and range of motion [ROM]) were pooled using a standardized mean difference (SMD) with their corresponding 95% confidence intervals (CIs) to estimate the effect size, while dichotomous data (complication rate, revision rate) were pooled to obtain the relative risk (RR) with a 95% CI by STATA 13.0 software.Results:Eleven studies involving 498 patients undergoing robotic-assisted UKA and 589 patients receiving conventional UKA were included. Our pooled results demonstrated that robotic-assisted could significantly reduce the complication rate (RR: 0.62, 95% CI: 0.45–0.85; P = .0041) and improve the knee excursion during weight acceptance (SMD: 0.62, 95% CI: 0.25–1.00; P = .001), but prolonged the surgical time (SMD: 0.74, 95% CI: 0.40–1.08; P < .001). No significant difference in the revision rate, AKSS, OKS, FJS, VAS, and ROM between robotic-assisted and conventional UKA groups.Conclusion:This meta-analysis demonstrates robotic-assisted UKA may be an effective and safe surgical procedure for treatment of unicompartmental knee osteoarthritis.

Despite increased utilization of robotic assistance during unicompartmental knee arthroplasty (UKA), its impact on postoperative outcomes remains unclear. This study aimed to compare rates of postoperative revision and complications among patients undergoing robotic-assisted UKA (RA-UKA) versus manual UKA. A retrospective matched cohort study was performed. Trends analysis of the annual proportion of RA-UKA between 2010 and 2021 was performed, and RA-UKA patients (n= 3976) were matched 1:3 with manual UKA patients (n= 11,766) across age, sex, Elixhauser Comorbidity Index, and comorbidities. Rates of 2-year prosthesis-related complications were compared between the matched cohorts using multivariable logistic regression. The annual proportion of UKA procedures performed with robotic assistance trended significantly upward (1.51% to 5.19%, P < .001). Within 2 years postoperatively, the RA-UKA cohort exhibited significantly lower rates of aseptic revision (1.84% vs 2.37%; odds ratio: 0.76; P= .040) and aseptic loosening (0.13% vs 0.42%; odds ratio: 0.32; P= .010). Total cost for the index UKA was significantly higher for the RA-UKA cohort ($10,321 vs $7,366; P < .001). There has been a marked increase in utilization of RA-UKA. Compared to matched manual UKA, RA-UKA had lower rates of revision and aseptic loosening at 2-year follow-up, but at a higher total cost for the index procedure. Further research exploring the use of robotics in UKA with attention to patient outcomes and cost is crucial for defining its evolving role in orthopaedic surgery.

Robotic-assisted unicompartmental knee arthroplasty (R-UKA) has been proposed as an approach to improve the results of the conventional manual UKA (C-UKA). The aim of this meta-analysis was to analyze the studies comparing R-UKA and C-UKA in terms of clinical outcomes, radiological results, operating time, complications, and revisions. The literature search was conducted on three databases (PubMed, Cochrane, and Web of Science) on 20 February 2024 according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Inclusion criteria were comparative studies, written in the English language, with no time limitations, on the comparison of R-UKA and C-UKA. The quality of each article was assessed using the Downs and Black Checklist for Measuring Quality. Among the 3,669 articles retrieved, 21 studies on 19 series of patients were included. A total of 3,074 patients (59.5% female and 40.5% male; mean age 65.2 years (SD 3.9); mean BMI 27.4 kg/m2 (SD 2.2)) were analyzed. R-UKA obtained a superior Knee Society Score improvement compared to C-UKA (mean difference (MD) 4.9; p < 0.001) and better Forgotten Joint Score postoperative values (MD 5.5; p = 0.032). The analysis of radiological outcomes did not find a statistically significant difference between the two approaches. R-UKA showed longer operating time (MD 15.6; p < 0.001), but reduced complication and revision rates compared to C-UKA (5.2% vs 10.1% and 4.1% vs 7.2%, respectively). This meta-analysis showed that the robotic approach for UKA provided a significant improvement in functional outcomes compared to the conventional manual technique. R-UKA showed similar radiological results and longer operating time, but reduced complication and revision rates compared to C-UKA. Overall, R-UKA seems to provide relevant benefits over C-UKA in the management of patients undergoing UKA.

PurposeAs robotic‐assisted unicompartmental knee arthroplasty (RA‐UKA) gains popularity, debate continues over its superiority to conventional UKA (C‐UKA). Systematic reviews and meta‐analyses (SRMAs) have examined this, but concerns exist about spin bias in their abstracts, which can significantly alter perceptions of a treatment's efficacy and safety. This study aims to evaluate the presence of spin bias in the abstracts of SRMAs comparing RA‐UKA and C‐UKA, and to assess the methodological quality of all included SRMAs using the AMSTAR‐2 tool.MethodsMEDLINE, EMBASE and the Cochrane Database of Systematic Reviews were searched from inception to 7 February 2025 for SRMAs that assessed RA‐UKA. Eligible studies assessed at least one outcome of RA‐UKA. Included studies were evaluated for the presence of spin in their abstracts using the methods outlined by Yavchitz et al. All full texts were subsequently assessed for methodological quality using the AMSTAR‐2 tool.ResultsAt least one element of abstract spin was identified in 12 of 16 included studies (75%). The most common category of spin was ‘misleading reporting’ in the form of selective reporting of or overemphasis on efficacy outcomes or analysis favouring the beneficial effect of the experimental intervention, observed in ten studies (63%). With the exception of one study with an overall ‘low’ confidence rating, all remaining studies were of ‘critically low’ A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR‐2) confidence. No study characteristics were significantly associated with the presence of abstract spin.ConclusionThe majority of RA‐UKA SRMAs contained spin, most commonly in the form of misleading reporting and interpretation, and were rated ‘critically low’ in quality by AMSTAR‐2. In a growing field like RA‐UKA where clinical decision‐making is influenced by SRMA results and conclusions, clinicians should critically review full texts to minimise the impact these biases may have on their practice.Level of EvidenceLevel IV.

Patient-specific instrumentation (PSI) can be applied in unicompartmental knee arthroplasty (UKA) to assist surgeons in planning and positioning prostheses. This study aims to compare the accuracy of prosthesis positioning in medial UKA performed with a newly designed PSI tool to those of UKA performed with robotic assistance and previously reported PSI-assisted techniques. Ninety-one patients underwent medial mobile-bearing UKA with the new PSI tool designed based on preoperative CT scans from May 2023 to June 2024. Deviations between planned and actual postoperative positions of femoral and tibial components in the coronal, sagittal, and axial planes were measured with CT overlay, and root mean square error (RMSE) was calculated. Accuracy was benchmarked by comparing the proportion of deviations within 2° with published robotic-assisted UKA data. Median absolute deviation (MAD) was compared with those of previous PSI studies. Cases of prosthesis size adjustment and PSI failure were also recorded. RMSE values for femoral component angle deviations were 2.0°, 3.7°, and 2.8° in coronal, sagittal, and axial planes; for the tibial component, values were 1.5°, 1.8°, and 2.6°, respectively. MAD values were consistently low, and angular deviations were generally comparable or superior to robotic-assisted UKA. In 4 cases (4.4%), prosthetic size was adjusted intraoperatively. The newly designed PSI tool effectively achieves the preoperative planning goals in medial mobile-bearing UKA. When compared with the published results of robotic-assisted and PSI-guided UKA, this tool provides comparable or even superior component positioning accuracy, demonstrating its potentials for wider clinical applications.

Unicompartmental knee arthroplasty (UKA) is a viable alternative to total knee arthroplasty (TKA) for osteoarthritis patients with single-compartment involvement, with advantages including accelerated recovery, reduced pain, and improved function. Robotic-assisted UKA (rUKA) is a promising development that ensures precise implant positioning and limb alignment. However, concerns about complications remain. This study looks at patient satisfaction as a key metric for determining the efficacy of rUKA versus manual UKA (mUKA). The search strategy for this study followed PRISMA. Using precise keywords, PubMed, Scopus, Web of Science, and the Cochrane library were searched. English articles were searched until August 2, 2023. Selection criteria included mUKA and rUKA patient satisfaction studies. The NOS scale evaluated study quality. Meta-analysis was done with R and heterogeneity analysis. This systematic review examined 5 studies with 1060 UKAs (532 robotic-assisted and 528 manual). Variable satisfaction assessment methods were used. Three studies found no difference in patient satisfaction after robotic-assisted UKA, but two found a higher satisfaction. Meta-analysis showed robotic-assisted UKA improved patient satisfaction (OR = 1.72 [1.25-2.37]). Overall, most studies showed low risk of bias, except one with higher bias. This review suggests that robotic assistance may enhance patient satisfaction in UKA procedures.

Robotic-assisted unicompartmental knee arthroplasty (RAUKA) is an emerging area of interest. The purpose of this study was to compare (1) different patient demographic profiles; (2) annual primary and revision utilization rates; (3) risk factors for revision procedures; and (4) survivorship between RAUKA and manual UKA (MUKA). Using the PearlDiver database, patients who underwent RAUKA or MUKA between 2005 and 2014 within the Medicare database were identified, yielding a total of 35,061 patients (RAUKA = 13,617; manual = 21,444). Patient demographics (age, gender, comorbidities, Charlson-Comorbidity Index, and geographic region) were compared between cohorts. Annual primary and revision utilization rates as well as risk factors for revision procedures were also compared. Kaplan-Meier survivorship was also calculated. The Pearson χ2 test was used to test for significance in patient demographics, whereas the Welch t-test was used to compare the incidence of revisions as well as the revision burden (proportion of revisions to total sum of primary and revision procedures). Multivariate binomial logistic regression analysis was performed to compare risk factors for revision procedures. There were statistically significant differences in RAUKA versus MUKA patients with respect to age (p < 0.001), gender (p < 0.001), and region (p < 0.001). RAUKA procedures performed increased over 12-fold compared with manual, which increased only 4.5-fold. RAUKA procedures had significantly lower revision incidence (0.99 vs. 4.24%, p = 0.003) and revision burden (0.91 vs. 4.23%, p = 0.005) compared with manuals. For patients undergoing RAUKA, normal (19-24 kg/m2) and obese (30-39 kg/m2) body mass index (p < 0.05), congestive heart failure (p = 0.004), hypothyroidism (p < 0.001), opioid dependency (p = 0.002), and rheumatoid arthritis (p < 0.001) were risk factors for a revision procedure. Kaplan-Meier survival curve 3 years following the index procedure to all-cause revisions demonstrated that RAUKA patients maintained nearly 100% survivorship compared with manual patients who had 97.5% survivorship. The data demonstrate increased utilization of RAUKA in the United States. The current data indicated that RAUKA has significantly lower revision rates and improved survivorship compared with patients undergoing non-RAUKA within Medicare patients.

This study conducted a Bayesian network meta-analysis (NMA) to compare the imaging and functional outcomes of patient-specific instrument-assisted unicompartmental knee arthroplasty (P-UKA), robot-assisted unicompartmental knee arthroplasty (R-UKA), and conventional unicompartmental knee arthroplasty (C-UKA). A comprehensive search was performed on five electronic databases and major orthopedic journals as of September 24, 2023. We included randomized controlled studies featuring at least two interventions of P-UKA, R-UKA, or C-UKA. Primary outcomes encompassed the deviation angle of hip-knee-ankle angle, as well as the coronal and sagittal plane alignment of femoral and tibial components. Secondary outcomes included patient-reported outcome measures (PROM), surgery time, revision rate, and complication rate. Bayesian framework was employed for risk ratio (RR) or mean deviation (MD) analysis, and treatment hierarchy was established based on rank probabilities. This NMA included 871 knees from 12 selected studies. In sagittal plane, R-UKA exhibited a significantly reduced deviation angle of femoral component compared to P-UKA (MD: 4.16, 95% CI: 0.21, 8.07), and of tibial component in comparison to C-UKA (MD: -2.45, 95% CI: -4.20, -0.68). Notably, the surgery time was significantly longer in R-UKA than in C-UKA (MD: 15.98, 95% CI: 3.11, 28.88). However, no significant differences were observed in other outcomes. Compared with P-UKA or C-UKA, R-UKA significantly improves the femoral and tibial component alignment in the sagittal plane, although this does not translate into discernible differences in functional outcomes. Comprehensive considerations of economic and learning costs are imperative for the judicious selection of the appropriate procedure.

BackgroundSurvivorship of medial unicompartmental knee arthroplasty (UKA) is technique-dependent. Correct femoral-tibial component positioning associates with improved survivorship. Image-free robotic-assisted unicompartmental knee arthroplasty enables preoperative and intraoperative planning of alignment and assessment of positioning prior to execution. This study aimed to compare the radiological outcomes between robotic-assisted UKA (R-UKA) and conventional UKA (C-UKA).MethodsThis retrospective case control study involved 140 UKA (82 C-UKA and 58 R-UKA) performed at an academic institution between March 2016 to November 2020, with a mean follow-up of 3 years. Postoperative radiographs were evaluated for mechanical axis and femoral-tibial component position. Component position was measured by two methods: (1) femoral-tibial component contact point with reference to four medial-to-lateral quadrants of the tibial tray and (2) femoral-tibial component contact point deviation from the center of the tibial tray as a percentage of the tibial tray width. Baseline demographics and complications were recorded.ResultsThere was a higher mean component deviation in C-UKA compared with R-UKA using method 2 (17.2% vs. 12.8%; P = 0.007), but no difference in proportion of zonal outliers using method 1 (4 outliers in C-UKA, 5.1% vs. 1 outlier in R-UKA, 1.8%; P = 0.403). R-UKA showed no difference in mean mechanical alignment (C-UKA 5° vs. R-UKA 5°; P = 0.250). 2-year survivorship was 99% for C-UKA and 97% for R-UKA. Mean operative time was 18 min longer for R-UKA (P < 0.001).ConclusionImage-free robotic-assisted UKA had improved component medio-lateral alignment compared with conventional technique.

The purpose of this systematic overview was to identify, synthesise and critically appraise findings of meta-analyses on robot-assisted versus conventional unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The hypothesis was that robotic assistance would reduce complications and revision rates, yield better clinical scores, and improve component positioning and alignment. Two researchers independently conducted a literature search using Embase®, MEDLINE®, Web of Science, Allied and Complementary Medicine™ and Cochrane Database of Systematic Reviews on 2 November 2020 for meta-analyses (Level I-IV) on robotic assistance in UKA and/or TKA. Outcomes were tabulated and reported as weighted mean difference (WMD), risk ratio (RR) or weighted odds ratio (WOR), and were considered statistically significant when p < 0.05. A total of ten meta-analyses were identified; four on robot-assisted UKA (n, 1880 robot-assisted vs. 2352 conventional UKA; follow-up, 0 to 60months), seven on robot-assisted TKA (n, 4567 robot-assisted vs. 5966 conventional TKA; follow-up, 0 to 132months). Of the meta-analyses on UKA, one found that robotic assistance reduced complication rates (relative risk (RR), 0.62), one found that it improved clinical scores (weighted mean difference (WMD), 19.67), three found that it extended operation times (WMD, 15.7 to 17.1min), and three found that it improved component positioning and alignment (WMD, - 1.30 to - 3.02 degrees). Of the meta-analyses on TKA, two found that robotic assistance improved clinical scores (WMD, 1.62-1.71), two found that that it extended surgery times (WMD, 21.5-24.26min), and five found that it improved component positioning and alignment (WMD, - 0.50 to - 10.07 degrees). None of the meta-analyses reported differences in survivorship between robot-assisted versus conventional knee arthroplasty. Robot-assisted knee arthroplasty enabled more accurate component positioning and placement within target zones, but extended operation time considerably. Although robotic assistance improved component positioning, its benefits regardingclinical scores, patient satisfaction and implant survivorship remains to be confirmed. Finally, this overview revealed that six of the ten meta-analyses were of 'critically low quality', calling for caution when interpreting results. IV.