Introduction. Robotic-assisted total knee arthroplasty (TKA) has demonstrated significant benefits, including improved accuracy of component positioning compared to conventional jig-based TKA. However, previous studies have often failed to associate these findings with clinically significant improvements in patient-reported outcome measures (PROMs). Inertial measurement units (IMUs) provide a more nuanced assessment of a patient's functional recovery after TKA. This study aims to compare outcomes of patients undergoing robotic-assisted and conventional TKA in the early postoperative period using conventional PROMS and wearable sensors. Method. 100 patients with symptomatic end-stage knee osteoarthritis undergoing primary TKA were included in this study (44 robotic-assisted TKA and 56 conventional TKA). Functional outcomes were assessed using ankle-worn IMUs and PROMs. IMU- based outcomes included impact load, impact asymmetry, maximum knee flexion angle, and bone stimulus. PROMs, including Oxford Knee Score (OKS), EuroQol-Five Dimension (EQ-5D-5L), EuroQol Visual Analogue Scale (EQ-VAS), and Forgotten Joint Score (FJS-12) were evaluated at preoperative baseline, weeks 2 to 6 postoperatively, and at 3-month postoperative follow-up. Results. By postoperative week 6, when compared to conventional TKA, robotic-assisted TKA was associated with significant improvements in maximum knee flexion angle (118o ± 6.6 vs. 113o ± 5.4; p=0.04), symmetrical loading of limbs (82.3% vs.22.4%; p<0.01), cumulative impact load (146.6% vs 37%; p<0.01), and bone stimulus (25.1% vs 13.6%; p<0.01). Whilst there were no significant differences in PROMs (OKS, EQ-5D-5L, EQ-VAS, and FJS-12) at any time point between the two groups, when comparing OKS subscales, significantly more robotic-assisted TKA patients achieved an ‘excellent’ outcome at 6 weeks compared to conventional (47% vs 41%, p= 0.013). Conclusions. IMU-based metrics detected an earlier return to function among patients that underwent robotic-assisted TKA compared to conventional TKA that PROMs were unable to detect within the first six weeks of surgery

Introduction. There is increasing pressure on healthcare providers to demonstrate competitiveness in quality, patient outcomes and cost. Robotic and computer-assisted total knee arthroplasty (TKA) have been shown to be more accurate than conventional TKA, thereby potentially improving quality and outcomes, however these technologies are usually associated with longer procedural times and higher costs for hospitals. The aim of this study was to determine the surgical efficiency, learning curve and early patient satisfaction of robotic-assisted TKA with a contemporary imageless system. Methods. The first 29 robotic-assisted TKA cases performed by a single surgeon having no prior experience with computer or robotic-assisted TKA were reviewed. System time stamps were extracted from computer surgical reports to determine the time taken from the first step in the anatomical registration process, the hip center acquisition, to the end of the last bone resection, the validation of the proximal tibial resection. Additional time metrics included: a) array attachment, b) anatomical registration, c) robotic-assisted femoral resection, d) tibial resection, e) trailing, f) implant insertion, and skin-to-skin time. The Residual Time was also calculated as the skin-to-skin time minus the time taken for steps a) to f), representing the time spent on all other steps of the procedure. Patients completed surveys at 3 months to determine their overall satisfaction with their surgical joint. Results. All time metrics decreased significantly after the first 7 cases, except the residual time (table 1 and figure 1). Mean skin-to-skin time significantly decreased from 83.7min to 57.1min (p=0.0008) beyond 7 cases, and hip center to final cut validation time decreased from 30.2min to 20.3min (p=0.0002). 85.7% (24/29) of patients were “Fully satisfied” and 14.3% (5/29) were “Partly satisfied”. Cost analysis showed there were no capital costs associated with acquisition of the robotic system and per case cost was equal to conventional TKA. Conclusion. Improvements in surgical efficiency and quality are becoming increasing important in today's healthcare environment. The results of this study indicated equal cost, a short learning curve and comparable procedure times to conventional TKA. The Patient Reported Outcomes with this group of patients was very high compared to rates reported in the literature

We sought to evaluate the early post-operative active range-of-motion (AROM) between robotic-assisted total knee arthroplasty (raTKA) and conventional TKA (cTKA). A secondary data analysis on a global prospective cohort study was performed. A propensity score method was used to select a matched control of cTKA from the same database using 1:1 ratio, based on age, sex, BMI, and comorbidity index. This resulted in 216 raTKA and cTKA matched cases. Multivariable longitudinal regression was used to evaluate difference in ROM over time and values are reported as least squares means (95% confidence interval). The longitudinal model tested the treatment effect (raTKA vs cTKA), time effect, and their interaction with control on covariance of patients ‘s age, sex, BMI, comorbidity and pre-operative flexion. Logistic regression was used to analyze the active flexion level at one month (cut by 90°) and three months (cut by 110°). At one-month postoperative the raTKA cases had more AROM for flexion by an average of 5.54 degrees (p<0.001). There was no difference at three months (p=0.228). The raTKA group had a greater improvement from pre-operative values at both one-month, with an average 7.07° (3.6°, 10.5°, p<0.001) more improvement, and at three-months with an average improvement of 4° more (1.61°, 7.24°, p=0.0115). AROM for extension was lower overall in the raTKA group by an average of 0.44° (p=0.029). The raTKA patients had higher odds of achieving ≥90° of flexion at one-month (OR 2.15, 95% CI 1.16, 3.99). raTKA resulted in greater AROM flexion gains in the early postoperative period than cTKA. Additional research is needed to understand if these earlier gains in AROM are associated with improved patient satisfaction and continued improvements with time

Introduction. Total knee arthroplasty (TKA) is a well established treatment option for patients with end stage osteoarthritis. Conventional TKA with manual instruments has been shown to be a cost effective and time efficient surgery. While robotic-assisted operative systems have been shown to have benefits in surgical accuracy, they have also been reported to have longer surgical times. The purpose of this work was to determine surgical time and learning curve for a novel robotic-assisted TKA platform. Methods. Eighty-five subjects underwent robotic-assisted TKA by one of three investigators as part of an FDA and IRB approved Investigational Device Exemption (IDE). All patients received a cruciate retaining total knee implant system. Intra-operative safety, Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Knee Society Scores (KSS) were collected pre-operatively and at three month follow-up. In addition, surgical times were collected as part of a TKA work flow. To identify activities related to surgical steps required for robotic procedures specific time stamps were determined from the system. Capture of the hip center to final bone cut was used to define case time and identify robotic learning curve. Descriptive statistics were used to analyze results. Results. Surgeon one completed 24 cases, surgeon two completed 32, and surgeon three completed 29 cases in the study. An average surgical time of 44 minutes with standard deviation of 15.7 minutes was recorded. On average surgeons improved in surgical time with increasing cases as indicated by linear regression results. During initial cases, surgeons repeated intra-operative planning steps which decreased with the learning curve. In addition, the average WOMAC score improvement from pre-operative to three months was 33.1 ± 20.04 (p<0.0001). The average KSS Knee score improvement was 46.12 ± 19.68 (p<0.0001). Subjects recovered their pre-operative range of motion by three months post-operative. Conclusion. With cost related pressures in healthcare, hospitals and surgeons focus on improvements in surgical efficiency to stay competitive. The results of this study indicated comparable operative times to conventional TKA cases as reported in literature with the added benefit of optimizing surgical accuracy. Robotic solutions in TKA may become increasingly efficient as surgeons complete a learning curve

Introduction. Surgical outcome analysis has shifted from surgeon- to patient-reported outcome measures (PROM). High rates of dissatisfaction (13–20%) in PROM after TKA have persisted despite significant advances in pain-management, implant design and introduction of newer surgical techniques. The NAVIO robotic-assisted TKA (RA-TKA) was introduced in May 2017 as an integrative approach to planning, execution and evaluation in TKA surgery. The goal of this study was to assess differences PROM scores between conventional instrumented TKA (CI-TKA) and RA-TKA. Methods. Starting in December 2016, prospective data collection of PROM's was initiated in a single-surgeon total joint arthroplasty registry. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was collected for all patients pre-operatively, at three months and at one year post-operatively. In Group A, from December 2016 through May 2017, patients were treated with CI-TKA instrumentation. In Group B, from June 2017 through December 2018, surgery was performed with the NAVIO RA-TKA technique. The Journey II total knee prosthesis was used for all cases. Peri-operative management was consistent for all patients in both groups. Results. A total of 625 patients were available for analysis. 270 RA-TKA and 355 CI-TKA. The results showed a trend toward higher scores for RA-TKA for KOOS overall (p-value = 0.20) and subspecialty scores at 1-year postop, especially for pain and quality of life (p-value = 0.13) and pain (p-value = 0.12). Discussion/Conclusion. In this preliminary study, patients undergoing RA-TKA demonstrated a trend toward higher PROM scores, especially in the categories of Quality of Life and Pain, when compared to CI-TKA. Due to the limited sample size, weighted 1.3:1 for CI-TKA, statistical significance was not shown. Because of the short timeframe available since the introduction of RA-TKA, further data collection and analysis will be necessary to re-assess statistically power in this comparison

The use of robotics in total joint arthroplasty is the latest in a long list of expensive technologies that promise multiple positive outcomes, but come with an expensive price tag. In the last decade alone we've seen the same claims for navigation and patient specific instruments and implants. There are various current systems available including a robotic arm, robotic-guided cutting jigs and robotic milling systems. For robotics to be widely adopted it will need to address the following concerns, which as of 2017 it has not. 1). Cost - Very clearly the robotic units come with a significant price tag. Perhaps over time, like other technologies, they will reduce, but at present they are prohibitive for most institutions. 2). Outcomes - One could perhaps justify the increased costs if there was compelling evidence that either outcomes were improved or revision rates reduced. Neither of these has been proved in any type of randomised trial or registry captured data. As with any new technology one must be wary of the claims superseding the results. In 2017 the jury is still out on the cost vs. benefit of robotic-assisted TKA

Introduction/Aim. The NAVIO robotic-assisted TKA (RA-TKA) application received FDA clearance in May 2017. This semi-active robotic technique aims to improve the accuracy and precision of total knee arthroplasty. The addition of robotic-assisted technology, however, also introduces another potential source of surgery-related complications. This study evaluates the safety profile of NAVIO RA-TKA. Materials and Methods. Beginning in May 2017, the first 250 patients undergoing NAVIO RA-TKA were included in this study. All intra-operative complications were recorded, including: bleeding; neuro-vascular injury; peri-articular soft tissue injury; extensor mechanism complications; and intra-operative fracture. During the first 90 days following surgery, patients were monitored for any post-operative complications, including: superficial and deep surgical site infection; pin-tract infection; pin site fractures; peri-prosthetic fractures; axial or sagittal joint instability; axial mal-alignment; patello-femoral instability; DVT/PE; re-operation or re-admission due to surgical-related complications. Surgical technique and multi-modality pain management protocol was consistent for all patients in the study. A combined anesthetic technique was employed for all cases, including: low-dose spinal, adductor canal block and general anesthetic. Patients were mobilized per our institution's rapid recovery protocol. Results. No patients were lost to follow-up. During the study period, no intra-operative complications were recorded. Specifically, no complications related to the introduction of the high-speed burr associated with the NAVIO RA-TKA were noted. Within the 90-day follow-up period, there was one case of deep infection. One patient sustained a fall resulting in a peri-prosthetic femoral fracture, that occurred remote from the femoral pin tracts. No cases of axial or sagittal joint instability, axial mal-alignment, patello-femoral instability, pin site infections or fractures; or DVT/PE were identified. Four patients underwent manipulation under anesthesia. No other patients required a re-operation or re-admission due to surgical-related complications. Discussion/Conclusions. The initial experience with the NAVIO robotic assisted total knee arthroplasty has demonstrated excellent safety profile. Relative to known risks associated with total knee arthroplasty, no increased risk of peri-operative complications, re-operation or re-admission for surgical related complications was identified with the introduction of the NAVIO RA-TKA

Introduction. Robotic systems have been used in TKA to add precision, although few studies have evaluated clinical outcomes. We report on early clinical results evaluating patient reported outcomes (PROs) on a series of robotic-assisted TKA (RAS-TKA) patients, and compare scores to those reported in the literature. Methods. We prospectively consented and enrolled 106 patients undergoing RAS-TKA by a single surgeon performing a measured-resection femur-first technique using a miniature bone-mounted robotic system. Patients completed a KOOS, New Knee Society Score (2011 KSS) and a Veterans RAND-12 (VR-12) pre-operatively and at 3, 6 and 12 months (M) post- operatively. At the time of publication 104, 101, and 78 patients had completed 3M, 6M, and 12M PROs, respectively. Changes in the five KOOS subscales (Pain, Symptoms, Activities of Daily Living (ADL), Sport and recreation function (Sport/Rec) and Knee-related Quality of Life (QOL)) were compared to available literature data from FORCE – TJR, a large, prospective, national cohort of TJR patients enrolled from diverse high-volume centers and community orthopaedic practices in the U.S, as well as to individual studies reporting on conventional (CON-TKA) and computer-assisted (CAS- TKA) at 3M, and on conventional TKA at 6M. The 2011 KSS is a validated method for quantifying patient's expectations and satisfaction with their TKA procedure. Improvements in the 2011 KSS were compared with literature data at 6M post-operatively. Results. RAS-TKA PRO's significantly improved at 3, 6, and 12M from pre-operative baseline values. When compared to the FORCE registry cohort data, the improvement in KOOS subscales were generally higher for RAS for pain at 6M, and for pain, ADL, and QOL at 1Y when compared with FORCE 2Y data. Higher improvements were also seen at 3M, except for Sports/Rec, and at 6M for symptoms and QOL when compared with smaller cohort studies. Improvements in 2011 KSS patient satisfaction and functional scores at 6M were 11 and 10 points greater than those reported for conventional TKA. A mean of 31 pts for the Patient Satisfaction score indicates that on average patients were ‘Satisfied’ with their knee function and pain level. Mean rates of dissatisfaction with knee pain level and function were 9.2%, 3.8% and 3.1% at 3, 6, and 12M postoperatively, respectively. A mean of 10pts for the Expectation score post-operatively indicates that on average patients felt their expectations for pain relief, ADL, and leisure/sports/rec activities were between “Just Right” or “Too Low”. Discussion. Early results of RAS-TKA demonstrated significant improvements in pain, function, and QOL from baseline pre-operative values. PROs for robotic TKA also compared favorably with results reported in the literature; however, additional randomized control studies are required to provide more meaningful comparisons with conventional techniques and with other advanced technologies

Total knee arthroplasty is a successful procedure with good long-term results. Studies indicate that 15% – 25% of patients are dissatisfied with their total knee arthroplasty. In addition, return to sports activities is significantly lower than total hip arthroplasty with 34% – 42% of patients reporting decreased sports participation after their total knee arthroplasties. Poor outcomes and failures are often associated with technical errors. These include malalignment and poor ligament balancing. Malalignment has been reported in up to 25% of all revision knee arthroplasties, and instability is responsible for over 20% of failures. Most studies show that proper alignment within 3 degrees is obtained in only 70% – 80% of cases. Navigation has been shown in many studies to improve alignment. In 2015, Graves examined the Australian Joint Registry and found that computer navigated total knee arthroplasty was associated with a reduced revision rate in patients under 65 years of age. Navigation can improve alignment, but does not provide additional benefits of ligament balance. Robotic-assisted surgery can assist in many of the variables that influence outcomes of total knee arthroplasty including: implant positioning, soft tissue balance, lower limb alignment, proper sizing. The data on robotic-assisted unicompartmental arthroplasty is quite promising. Cytech showed that femoral and tibial alignment were both significantly more accurate than manual techniques with three times as many errors with the manually aligned patients. Pearle, et al. compared the cumulative revision rate at two years and showed this rate was significantly lower than data reported in most unicompartmental series, and lower revision rates than both Swedish and Australian registries. He also showed improved satisfaction scores at two years. Pagnano has noted that optimal alignment may require some deviation from mechanically neutral alignment and individualization may be preferred. This is also likely to be a requirement of more customised or bi-cruciate retaining implant designs. The precision of robotic surgery may be necessary to obtain this individualised component alignment. While robotic total knee arthroplasty requires further data to prove its value, more precise alignment and ligament balancing is likely to lead to improved outcomes, as Pearl, et al. and the Australian registry have shown. While it is difficult to predict the future at this time, I believe robotic-assisted total knee arthroplasty is the future and that future begins now

Introduction/Aim. Mid-flexion instability is a well-documented, but often poorly understood cause of failure of TKA. NAVIO robotic-assisted TKA (RA-TKA) offers a novel, integrative approach as a planning, execution as well as an evaluation tool in TKA surgery. RA-TKA provides a hybrid planning technique of measured resection and gap balancing- generating a predictive soft-tissue balance model, prior to making cuts. Concurrently, the system uses a semi-active robot to facilitate both the execution and verification of the plan, as it pertains to both the static and dynamic anatomy. The goal of this study was to assess the ability of the NAVIO RA-TKA to plan, execute and deliver an individualized approach to the soft-tissue balance of the knee, specifically in the “mid-flexion” arc of motion. Materials and Methods. Between May and September 2018, 50 patients underwent NAVIO RA-TKA. Baseline demographics were collected, including age, gender, BMI, and range of motion. The NAVIO imageless technique was used to plan the procedure, including: surface-mapping of the static anatomy; objective assessment of the dynamic, soft-tissue anatomy; and then application of a hybrid of measured-resection and gap-balancing technique. Medial and lateral gaps as predicted by the software were recorded throughout the entire arc of motion at 15° increments. After executing the plan and placing the components, actual medial and lateral gaps were recorded throughout the arc of motion. Results. In the assessment of coronal-plane balance, the average deviation from the predicted plan between 0–90° was 0.9mm in both the medial and lateral compartments (range 0.5–1.2mm). In the mid-flexion arc (15–75°), final soft-tissue stability was within 1.0mm of the predictive plan (range 0.9–1.2mm). Discussion/Conclusions. In this study, NAVIO RA-TKA demonstrated a highly accurate and reproducible surgical technique to plan, execute and verify a balanced a soft-tissue envelope in TKA. Objective soft-tissue balancing of the TKA can now be performed, including the mid-flexion arc of motion. Further analysis can determine if these objective measurements will translate into improved patient-reported outcome scores

Arthrofibrosis remains a dominant post-operative complication and reason for returning to the OR following total knee arthroplasty. Trauma induced by ligament releases during TKA soft tissue balancing and soft tissue imbalance are thought to be contributing factors to arthrofibrosis, which is commonly treated by manipulation under anesthesia (MUA). We hypothesized that a robotic-assisted ligament balancing technique where the femoral component position is planned in 3D based on ligament gap data would result in lower MUA rates than a measured resection technique where the implants are planned based solely on boney alignment data and ligaments are released afterwards to achieve balance. We also aimed to determine the degree of mechanical axis deviation from neutral that resulted from the ligament balancing technique. Methods. We retrospectively reviewed 301 consecutive primary TKA cases performed by a single surgeon. The first 102 consecutive cases were performed with a femur-first measured resection technique using computer navigation. The femoral component was positioned in neutral mechanical alignment and at 3° of external rotation relative to the posterior condylar axis. The tibia was resected perpendicular to the mechanical axis and ligaments were released as required until the soft tissues were sufficiently balanced. The subsequent 199 consecutive cases were performed with a tibia-first ligament balancing technique using a robotic-assisted TKA system. The tibia was resected perpendicular to the mechanical axis, and the relative positions of the femur and tibia were recorded in extension and flexion by inserting a spacer block of appropriate height in the medial and lateral compartments. The position, rotation, and size of the femoral component was then planned in all planes such that the ligament gaps were symmetric and balanced to within 1mm (Figure 1). Bone resection values were used to define acceptable limits of implant rotation: Femoral component alignment was adjusted to within 2° of varus or valgus, and within 0–3° of external rotation relative to the posterior condyles. Component flexion, anteroposterior and proximal-distal positioning were also adjusted to achieve balance in the sagittal plane. A robotic-assisted femoral cutting guide was then used to resect the femur according to the plan (Figure 2). CPT billing codes were reviewed to determine how many patients in each group underwent post-operative MUA. Post-operative mechanical alignment was measured in a subset of 50 consecutive patients in the ligament balancing group on standing long-leg radiographs by an independent observer. Results. Post-operative MUA rates were significantly lower in the ligament balancing group (0.5%; 1/199) than in the measured resection group (3.9%; 4/102), p=0.051. 91.3% (42/46) of knees were within 3° and 100% (46/46) were within 4° of neutral alignment to the mechanical axis post-operatively in the ligament balancing group. Conclusions. Gap driven femoral based planning in TKA resulted in a significantly lower post-operative manipulation rate than in the measured resection approach, while maintaining acceptable overall alignment to the mechanical axis

We introduce a novel active tensioning system that can be used for dynamic gap-based implant planning as well as for assessment of final soft tissue balance during implant trialing. We report on the concept development and preliminary findings observed during early feasibility testing in cadavers with two prototype systems. System description. The active spacer (fig 1) consists of a motorized actuator unit with integrated force sensors, independently actuated medial and lateral upper arms, and a set of modular attachments for replicating the range of tibial baseplate and insert trial sizes. The spacer can be controlled in either force or position (gap) control and is integrated into the OMNIBotics. TM. Robotic-assisted TKA platform (OMNI, MA, USA). Cadaver Study. Two design iterations were evaluated on eleven cadaver specimens by seven orthopaedic surgeons in three separate cadaver labs. The active spacer was used in a tibial-first technique to apply loads and measure gaps prior to and after femoral resections. To determine the range of forces applied on the spacer during a varus/valgus assessment procedure, each surgeon performed a varus/valgus stress test and peak medial and lateral forces were measured. Surgeons also rated the feel of the stability of the knee at 50N and 80N of preload using the following scale: 1 – too loose; 2 – slightly loose; 3 – ideal; 4 slightly tight; 5 – too tight. Final balanced was assessed with the spacer and with manual trial components. Results. Overall the prototype system successfully met the functional requirements for applying controlled tension during ligament balancing, and user feedback on usability and feasibility for use in TKA was highly positive. Peak forces measured during blinded stability assessments were significantly imbalanced from medial to lateral and exhibited a wide range across users (range: 70N – 310N, table 1). Each surgeon rated 50N of tension as feeling “slightly loose” and 80N as feeling “ideal” in extension. “Ideal” soft tissue balance was achieved in the last three knees tested using the second design iteration, as rated by the surgeons with final trial components in place. Discussion. Our preliminary cadaver results have established the initial feasibility of the active spacer concept for applying tension during ligament balancing and implant planning. Our initial results also suggest that performing a varus/valgus assessment without force readings can lead to imbalanced mediolateral load application. This may be due to factors such as hand dominance and pulling in varus versus pushing in valgus. There was also considerable inter-surgeon variability in the peak forces applied. An advantage of computer-controlled ligament tensioning and force sensing is ability to standardize applied mediolateral forces across patients and surgeons. In the assessment of the ‘ideal' static ligament tension in extension a force of 80N was preferred over 50N, which is in the range of forces applied by others during ligament balancing. What is the ideal patient specific force to apply remains a topic of future research. Our next steps will be to further evaluate use of the system in the context of virtual trialing

Introduction. Component position and overall limb alignment following total knee arthroplasty (TKA) have been shown to influence prosthetic survivorship and clinical outcomes. Robotic-assisted (RA) total knee arthroplasty has demonstrated improved accuracy to plan in cadaver studies compared to conventionally instrumented (manual) TKA, but less clinical evidence has been reported. The objective of this study was to compare the three-dimensional accuracy to plan of RATKA with manual TKA for overall limb alignment and component position. Methods. A non-randomized, prospective multi-center clinical study was conducted to compare RATKA and manual TKA at 4 U.S. centers between July 2016 and August 2018. Computed tomography (CT) scans obtained approximately 6 weeks post-operatively were analyzed using anatomical landmarks. Absolute deviation from surgical plans were defined as the absolute value of the difference between the CT measurements and surgeons’ operative plan for overall limb, femoral and tibial component mechanical varus/valgus alignment, tibial component posterior slope, and femoral component internal/external rotation. We tested the differences of absolute deviation from plan between manual and RATKA groups using stratified Wilcoxon tests, which controlled for study center and accounted for skewed distributions of the absolute values. Alpha was 0.05 two-sided. At the time of this abstract, data collections were completed for two centers (52 manual and 58 RATKA). Results. Comparing absolute deviation from plan between groups, RATKA demonstrated clear benefits for tibial component alignment (median absolute deviation from plan: 1.5° vs. 0.8°, manual vs RATKA, p<.001), tibial slope (2.7° vs. 1.1°, manual vs RATKA, p<.001), and femoral component rotation (1.4° vs. 0.9°, manual vs RATKA, p<0.02). Femoral component and overall limb alignment accuracy were comparable (p>0.10). Discussion and Conclusions. In this study, compared to manual TKA, RATKA cases were 47% more accurate for tibial component alignment, 59% more accurate for tibial slope, and 36% more accurate for femoral component rotation (percent differences of median absolute deviations from plan). Further clinical data is needed to study the longer-term benefits of robotic technologies. Nevertheless, this study supports improved accuracy to plan utilizing RATKA compared to manual TKA. For any figures or tables, please contact authors directly

Introduction

Valgus deformity in an end stage osteoarthritic knee can be difficult to correct with no clear consensus on case management. Dependent on if the joint can be reduced and the degree of medial laxity or distension, a surgeon must use their discretion on the correct method for adequate lateral releases. Robotic assisted (RA) technology has been shown to have three dimensional (3D) cut accuracy which could assist with addressing these complex cases. The purpose of this work was to determine the number of soft tissue releases and component orientation of valgus cases performed with RA total knee arthroplasty (TKA).

Introduction

Studies have shown that dissatisfaction following TKA may stem from poor component placement and iatrogenic factors related to variability in surgical execution. A CT-based robotic assisted system (RA) allows surgeons to dynamically balance the joint prior to bone resection. This study aimed to determine if this system could improve TKA planning, reduce soft tissue releases, minimize bone resection, and accurately predict component size in varus knee.

Introduction

Component position and overall limb alignment following Total Knee Arthroplasty (TKA) have been shown to influence device survivorship and clinical outcomes. However current methods for measuring post-operative alignment through 2D radiographs and CTs may be prone to inaccuracies due to variations in patient positioning, and certain anatomical configurations such as rotation and flexion contractures. The purpose of this paper is to develop a new vector based method for overall limb alignment and component position measurements using CT. The technique utilizes a new mathematical model to calculate prosthesis alignment from the coordinates of anatomical landmarks. The hypothesis is that the proposed technique demonstrated good accuracy to surgical plan, as well as low intra and inter-observer variability.

Introduction

Innovations in surgical robotics and navigation have significantly improved implant placement accuracy in total knee arthroplasty (TKA). However, many comparative studies have not been shown to substantially improve revision rates or other clinical outcome scores. We conducted a simulation study based on the reported distribution of patient-specific characteristics and estimated potential effect of coronal plane alignment (CPA) on risk of revision to evaluate the hypothesis that most published study designs in this area have been too underpowered to detect improvements in revision rates.

Introduction

Semi-active robots can improve the accuracy and precision of total knee arthroplasty (TKA). The surgical efficiency of the recently introduced NAVIO robotic-assisted (RA-TKA) surgery was assessed in this study to define: (1) the time commitment for RA-TKA; (2) the learning curve for RA-TKA; and (3) to compare RA-TKA surgical time commitment to conventional, instrumented TKA (CI-TKA).

Gap balancing technique aims to achieve equal and symmetric gap at full extension and in flexion; however, little is known about the connection between the native and the replaced knee gaps. In this study, a novel robotic assisted ligament tensioning tool was used to measure the pre- and post- operative gaps to better understand their relationship when aiming for balance gaps in flexion and extension. The accuracy of a prediction algorithm for the post-operative gaps based on the native gap and implant alignment was evaluated in this study. The medial and lateral gap were smallest at full extension. The native gaps increase with flexion until 30 degrees where they plateaued for the remaining flexion range. The native lateral gap was larger than the medial gap throughout the flexion range. Planning for equal gaps at extension and flexion resulted with tightest gaps at these angle; however, the gaps in mid-flexion were 3–4 mm larger. Good agreement was observed between the post-operative results and the predicted gas from the software algorithm. The results showed that the native gaps are neither symmetric nor equal. In addition, aiming for equal gaps reduces the variation at these angles but could result in mid- flexion laxity. Advanced robotics-assisted instrumentation can aid in evaluation of soft-tissue and help in surgical planning of TKA. This allows the surgeon to achieve the targeted outcome as well as record the final implant tension to correlate with clinical outcomes.

Introduction

We evaluated the utility of imageless computer-navigation coupled with a miniature robotic-cutting guide for managing large deformities in TKA. We asked what effect did severe pre-operative deformities have on post-operative alignment and surgery time using the system. We also report on the early functional outcomes of this group of patients.