Purpose. Various alignment philosophies for total knee arthroplasty (TKA) have been described, all striving to achieve excellent long-term implant survival and good functional outcomes. In recent years, in search of higher functionality and patient satisfaction, a shift towards more patient-specific alignment is seen. Robotics is the perfect technology to tailor alignment. The purpose of this study was to describe ‘inverse kinematic alignment’ (iKA) technique, and to compare clinical outcomes of patients that underwent robotic-assisted TKA performed by iKA versus adjusted mechanical alignment (aMA). Methods. The authors analysed the records of a consecutive series of patients that received robotic assisted TKA with iKA (n=40) and with aMA (n=40). Oxford Knee Score (OKS) and satisfaction on a visual analogue scale (VAS) were collected at a follow-up of 12 months. Clinical outcomes were assessed according to patient acceptable symptom state (PASS) thresholds, and uni- and multivariable linear regression analyses were performed to determine associations of OKS and satisfaction with 6 variables (age, sex, body mass index (BMI), preoperative hip knee ankle (HKA) angle, preoperative OKS, alignment technique). Results. The iKA and aMA techniques yielded comparable outcome scores (p=0.069), with OKS respectively 44.6±3.5 and 42.2±6.3. VAS Satisfaction was better (p=0.012) with iKA (9.2±0.8) compared to aMA (8.5±1.3). The number of patients that achieved OKS and satisfaction PASS thresholds was significantly higher (p=0.049 and p=0.003, respectively) using iKA (98% and 80%) compared to aMA (85% and 48%). Knees with preoperative varus deformity, achieved significantly (p=0.025) better OKS using iKA (45.4±2.0) compared to aMA (41.4±6.8). Multivariable analyses confirmed better OKS (β=3.1; p=0.007) and satisfaction (β=0.73; p=0.005) with iKA. Conclusions. The results of this study suggest that iKA and aMA grant comparable clinical outcomes at 12-months follow-up, though a greater proportion of knees operated by iKA achieved the PASS thresholds for OKS and satisfaction. Notably. in knees with preoperative varus deformity, iKA yielded significantly better OKS and satisfaction than aMA

Introduction. Technology in Orthopaedic surgery has become more widespread in the past 20 years, with emerging evidence of its benefits in arthroplasty. Although patients are aware of benefits of conventional joint replacement, little is known on patients' knowledge of the prevalence, benefits or drawbacks of surgery involving navigation or robotic systems. Materials & Methods. In an outpatient arthroplasty clinic, 100 consecutive patients were approached and given questionnaires to assess their knowledge of Navigation and Robotics in Orthopaedic surgery. Participation in the survey was voluntary. Results. 98 patients volunteered to participate in the survey, mean age 56.2 years (range 19–88; 52 female, 46 male). 40% of patients thought more than 30% of NHS Orthopaedic operations involved navigation or robotics; 80% believed this was the same level or less than the private sector. A third believed most of an operation could be performed independently by a robotic/navigation system. Amongst perceived benefits of navigation/robotic surgery was more accurate surgery(47%), quicker surgery (50%) and making the surgeon's job easier (52%). 69% believed navigation/robotics was more expensive and 20% believed it held no benefit against conventional surgery, with only 9% believing it led to longer surgery. Almost 50% would not mind at least some of their operation being performed with use of robotics/navigation, with a significantly greater proportion of these coming from patients aged under 50 years. Conclusions. Although few patients were familiar with this new technology, there appeared to be a strong consensus it was quicker and more accurate than conventional surgery. Many patients appear to believe navigation and robotics in Orthopaedic surgery is largely the preserve of the private sector. This study demonstrates public knowledge of such new technologies is limited and a need to inform patients of the relative merits and drawbacks of such surgery prior to their more widespread implementation

Background

Despite the success of total hip arthroplasty (THA), there are still challenges including restoration of leg length, offset, and femoral version. The Tsolution One combines preoperative planning with an active robotic system to assist in femoral canal preparation during a THA.

Introduction:

Unicompartmental knee arthroplasty has been shown to have lower morbidity, quicker rehabilitation and more normal kinematics compared to conventional TKA, but subchondral defects, or severe osteoarthritic changes, of the medial compartment may complicate component positioning. Successful UKA in these patients requires proper planning and exact placement of the components to ensure adequate and stable fixation and proper postoperative kinematics. This study presents a series of three patients with spontaneous osteonecrosis of the knee receiving a UKA with CT-based haptic robotic guidance.

There is an increasing prevalence of haptic devices in many engineering fields, especially in medicine and specifically in surgery. The stereotactic haptic boundaries used in Computer Aided Orthopaedic Surgery Unicomparmental Knee Arthroplasty (CAOS UKA) systems for assistive milling control can lead to an increase in the force required to manipulate the device; this study presented here has seen a several fold increase in peak forces between haptic and non-haptic conditions of a semi-active preoperative image system.

Orthopaedic Arthroplasty surgeons are required to apply forces ranging from large gripping forces to small forces for delicate manipulation of tools and through a large range of postures. There is also a need for surgeons to move around and position themselves to gain line of sight with the object of interest and to operate while wearing additional clothing such as the protective headwear and double gloves. These factors further complicate comparison with other ergonomic studies of other robotics systems. While robotics has been implemented to reduce fatigue in surgery one area of concern in CAOS is localised user muscle fatigue in high volume use.

In order to create the conditions necessary for the generation of fatigue in a realistic user experience, but in the time available for the participants, an extended period of controlled and prolonged cutting and manipulation of the robotic arm was needed. This pragmatic test requirement makes the test conditions slightly artificial but does indicate areas of high potential for fatigue when interacting with the system in high volume instances.

The surgeon-robotic system interaction was captured using 3 dimensional motion analysis and a force transducer embedded in the end effector of the robotic arm and modelled using an existing upper body model in Anybody software. The kinematic and force information allowed initial calculations of the interaction between the user and the Robotic system. Validation of the model was conducted using Electromyography assessment of activity and fatigue. Optimisation of the model sought to create an efficient cutting regime to reduce cutting time with reduced muscle force in an attempt to reduce users discomfort/fatigue while taking into account anthropometric variations in the users and minimising overall energy requirements, burr path length and maximum muscle force.

From the assessment of a small group of three surgeons with experience of the Robotic system there was little to no experience of above normal localised fatigue during small volume use of the system. Observation of these surgeons operating the robot state otherwise with examples of reactions to discomfort. There is also anecdotal evidence that fatigue becomes more problematic in higher volume work loads.

Introduction. Robotics have been applied to total knee arthroplasty (TKA) to improve surgical precision in component placement and joint function restoration. The purpose of this study was to evaluate prosthetic component alignment in robotic arm-assisted (RA)-TKA performed with functional alignment and intraoperative fine-tuning, aiming for symmetric medial and lateral gaps in flexion/extension. It was hypothesized that functionally aligned RA-TKA the femoral and tibial cuts would be performed in line with the preoperative joint line orientation. Methods. Between September 2018 and January 2020, 81 RA cruciate retaining (CR) and posterior stabilized (PS) TKAs were performed at a single center. Preoperative radiographs were obtained, and measures were performed according to Paley's. Preoperatively, cuts were planned based on radiographic epiphyseal anatomies and respecting ±3° boundaries from neutral coronal alignment. Intraoperatively, the tibial and femoral cuts were modified based on the individual soft tissue-guided fine-tuning, aiming for symmetric medial and lateral gaps in flexion/extension. Robotic data were recorded. Results. A total of 56 RA-TKAs performed on varus knees were taken into account. On average, the tibial component was placed at 1.9° varus (SD 0.7) and 3.3° (SD 1.0) in the coronal and sagittal planes, respectively. The average femoral component alignment, based on the soft tissue tensioning with spoons, resulted as follows: 0.7° varus (SD 1.7) in the coronal plane and 1.8° (SD 2.1) of external rotation relative to surgical transepicondylar axis in the transverse plane. A statistically significant linear direct relationship was demonstrated between radiographic epiphyseal femoral and tibial coronal alignment and femoral (r=0.3, p<0.05) and tibial (r=0.3, p<0.01) coronal cuts, resepctively. Conclusion. Functionally aligned RA-TKA performed in varus knees, aiming for ligaments’ preservation and balanced flexion/extension gaps, provided joint line respecting femoral and tibial cuts on the coronal plane

Introduction. Robotics have been applied to total knee arthroplasty (TKA) to improve surgical precision in components’ placement, providing a physiologic ligament tensioning throughout knee range of motion. The purpose of the present study is to evaluate femoral and tibial components’ positioning in robotic-assisted TKA after fine-tuning according to soft tissue tensioning, aiming symmetric and balanced medial and lateral gaps in flexion/extension. Materials and Methods. Forty-three consecutive patients undergoing robotic-assisted TKA between November 2017 and November 2018 were included. Pre-operative radiographs were performed and measured according to Paley's. The tibial and femoral cuts were performed based on the individual intra-operative fine-tuning, checking for components’ size and placement, aiming symmetric medial and lateral gaps in flexion/extension. Cuts were adapted to radiographic epiphyseal anatomy and respecting ±2° boundaries from neutral coronal alignment. Robotic data were recorded, collecting information relative to medial and lateral gaps in flexion and extension. Results. Patients were divided based on the pre-operative coronal mechanical femoro-tibial angle (mFTA). Only knees with varus deformity (mFTA<178°), 29 cases, were taken into account. On average, the tibial component was placed at 1.2°±0.5 varus. Femoral component fine-tuning based on soft-tissues tensioning in extension and flexion determined the following alignments: 0.2°±1.2 varus on the coronal plane and 1.2°±2.2° external rotation with respect to the trans-epicondylar axis (TEA) as measured on the CT scan in the horizontal plane. The average gaps after femoral and tibial resections, resulted as follows: 19.5±0.8 mm on the medial side in extension, 20.0±0.9 mm on the lateral side in extension, 19.1±0.7 mm on the medial side in flexion and 19.5±0.7 mm on the lateral side in flexion. On average, the post-implant coronal alignment as reported by the robotic system resulted 2.0°±1.5 varus. Discussion. The proposed robotic-arm assisted TKA technique, aiming to preserve the integrity of the ligaments, provides balanced and symmetric gaps in flexion and extension and an anatomic femoral and tibial component's placement with post-implant coronal alignment within ±2° from neutral alignment

One of the more difficult tasks in surgery is to apply the optimal instrument forces and torques necessary to conduct an operation without damaging the tissue of the patient. This is especially problematic in surgical robotics, where force-feedback is totally eliminated. Thus, force sensing instruments emerge as a critical need for improving safety and surgical outcome. We propose a new measurement system that can be used in real fracture surgeries to generate quantitative knowledge of forces/torques applied by surgeon on tissues. We instrumented a periosteal elevator with a 6-DOF load-cell in order to measure forces/torques applied by the surgeons on live tissues during fracture surgeries. Acquisition software was developed in LabView to acquire force/torque data together with synchronised visual information (USB camera) of the tip interacting with the tissue, and surgeon voice recording (microphone) describing the actual procedure. Measurement system and surgical protocol were designed according to patient safety and sterilisation standards. The developed technology was tested in a pilot study during real orthopaedic surgery (consisting of removing a metal plate from the femur shaft of a patient) resulting reliable and usable. As demonstrated by subsequent data analysis, coupling force/torque data with video and audio information produced quantitative knowledge of forces/torques applied by the surgeon during the surgery. The outlined approach will be used to perform intensive force measurements during orthopaedic surgeries. The generated quantitative knowledge will be used to design a force controller and optimised actuators for a robot-assisted fracture surgery system under development at the Bristol Robotics Laboratory

Purpose. The goal of Total Ankle Arthroplasty (TAA) is to relieve pain and restore healthy function of the intact ankle. Restoring intact ankle kinematics is an important step in restoring normal function to the joint. Previous robotic laxity testing and functional activity simulation showed the intact and implanted motion of the tibia relative to the calcaneus is similar. However there is limited data on the tibiotalar joint in either the intact or implanted state. This current study compares modern anatomically designed TAA to intact tibiotalar motion. Method. A robotic testing system including a 6 DOF load cell (AMTI, Waltham, MA) was used to evaluate a simulated functional activity before and after implantation of a modern anatomically designed TAA (Figure 1). An experienced foot and ankle surgeon performed TAA on five fresh-frozen cadaveric specimens. The specimen tibia and fibula were potted and affixed to the robot arm (KUKA Robotics Inc., Augsburg, Germany) while the calcaneus was secured to a fixed pedestal (Figure 1). Passive reflective motion capture arrays were fixed to the tibia and talus and a portable coordinate measuring machine (Hexagon Metrology Group, Stockholm, Sweden) established the location of the markers relative to anatomical landmarks palpated on the tibia. A four camera motion capture system (The Motion Monitor, Innovative Sports Training, Chicago, IL) recorded the movement of the tibia and talus. The tibia was rotated from 30 degrees plantar flexion to 15 degrees dorsiflexion to simulate motions during the stance phase of gait. At each flexion angle the robot found the orientation which zeroed all forces and torques except compressive force, which was either 44N or 200N. Results. Preliminary data indicates the tibiotalar motion of the TAA is similar to the intact ankle. The pattern and magnitude of tibiotalar translations and rotations are similar between the intact and implanted states for both 44N and 200N compressive loads (Figure 2). The most variation occurs with internal-external rotation. Increased translation especially in the anterior-posterior directions was observed in plantarflexion while the mediolateral translation remained relatively centered moving less than a millimeter. The intact talus with respect to the calcaneus had less than 3 degrees of rotation over the whole arc of ankle flexion (Figure 3). The angular motion of the implanted talus was similar in pattern to the intact talus, however there were offsets in all three angular directions which changed depending on the loading (Figure 3). This indicates that most of the motion that occurs between the intact tibial calcaneal complex occurs in the tibiotalar joint. Conclusion. Although more investigation is required, this study adds to the limited available tibiotalar kinematic data. This current study suggests the anatomical TAA design allows the tibiotalar joint to behave in similar way to the intact tibiotalar joint. Restoring intact kinematics is an important step in restoring normal function to the joint. For figures/tables, please contact authors directly.

Background. Robotics assisted surgery are tools that provide successful biomechanical reconstruction of the hip. We compare the accuracy of cup placement in the safe zones described by Lewinnek et al. and Callanan et al., leg length discrepancy (LLD) and global offset (GO) measurement in total hip arthroplasty (THA) using five diferent image guided techniques performed by six diferent surgeons. Methods. Between June 2008 and April 2014, 2330 THRs were performed by six different surgeons. Ninety-three (4.69%) patients underwent robotic-assisted THA anterior approach, 135 (6.8%) had robotic-assisted THA posterior approach, 942 (47.5%) patients underwent fluoroscopic guided THA anterior approach, 708 (35.7%) had THA without guidance using posterior approach, 43 (2.1%) patients underwent navigation-guided anterior approach and 59 (2.9%) patients underwent radiographic-guided posterior approach THAs (Figure 1). Results. One Thousand, nine hundred-eigthy patients met the inclusion and exclusion criteria. Robotic guidance groups had a significantly greater percentage of hips in the Lewinnek's and Callanan's safe zone (p < 0.005). Between robotic guidance groups, the group with posterior approach has more cups placed in the Lewinnek's and Callanan's safe zone (p < 0.005). The frequency of hips within the Lewinnek's safe zone was significantly greater in the navigation guided group, compared to the other groups except robotic guided (p < 0.05) (Figure 2). Sixty-four (3.2%) of our cases were with LLD greater than or equal to 10mm, five of those cases were (8.5%) in the group treated with x-ray guidance (p < 0.05) (Figure 3). The mean GOD for the overall cohort was 4.0mm ± 0.4mm (p < 0.0001) (Figure 3). Mean ages of patients in the treatment groups were significantly different (p < 0.0001). Conclusion. Robotic assisted surgery was more consistent than the other techniques in placing the acetabular cup into the Lewinnek and Callanan safe zone. In general, we can conclude that the useof the robot in hip arthroplasty surgery is more accurate fulfilling the goals needed to actual hip arthroplasty. We know new technologies will be developed

1. Role of enabling technologies in THA: Setting the stage. a. Impact of component position in THA. 1. Wear/lysis. Effect of edge loading, impingement. 2. Instability. Together, the most common cause for revision hip arthroplasty. b. Ideal component position:. 1. Work of Lewinneck: the “safe zone” for stability. c. Can we achieve this?. 1. HSS study. 2. Mass General Study: 2000 THR's, only 50% within desired range. d. Need for assistance? Maybe?. 2. Types of Guidance:. a. Navigation: use of mechano or optical tracking system that after some registration acquisition, facilitate spatial placement. The systems can either be image based (pre-operative CT scan) or imageless where multiple points are acquired and a “best fit” is matched to a library of pelvic geometries. b. Robotics: combines the spatial application of navigation with the precision bone preparation afforded by robotic milling. Robotic use can either be active whereby the robotic preparation is performed by the computer driven system (ie ROBODOC™). Alternatives include surgeon controlled but robot guided (haptic) type systems. 3. Perceived Advantages:. a. Robotic assisted: Bone preparation: spherical shape of socket consistently “rounder” than manually controlled reaming. Implant insertion: by establishing boundaries of insertion, final implant position achieves desired position. 4. Unknowns:. a. Cost effectiveness. b. Do we really know where the socket is best located for an individual patient?. While we rely on the safe zone of Lewinneck for our desired implant position, the impact of lumbosacral disease deformity could/should impact where the socket is placed

Introduction. Technology in Orthopaedic surgery has become more widespread in the past 20 years, with emerging evidence of its benefits in arthroplasty. Although patients are aware of benefits of conventional joint replacement, little is known on patients' knowledge of the prevalence, benefits or drawbacks of surgery involving navigation or robotic systems. Materials and methods. In an outpatient arthroplasty clinic, 100 consecutive patients were approached and given questionnaires to assess their knowledge of Navigation and Robotics in Orthopaedic surgery. Participation in the survey was voluntary. Results. 98 patients volunteered to participate in the survey, mean age 56.2 years (range 19–88; 52 female, 46 male). 40% of patients believed more than 30% of NHS Orthopaedic operations involved navigation or robotics; 80% believed this was the same level or less than the private sector. A third believed most of an operation could be performed independently by a robotic/navigation system. Amongst perceived benefits of navigation/robotic surgery was more accurate surgery(47%), quicker surgery (50%) and making the surgeon's job easier (52%). 69% believed navigation/robotics was more expensive and 20% believed it held no benefit against conventional surgery, with only 9% believing it led to longer surgery. Almost 50% would not mind at least some of their operation being performed with use of robotics/navigation, with a significantly greater proportion of these coming from patients aged under 50 years. Conclusions. Although few patients were familiar with this new technology, there appeared to be a strong consensus it was quicker and more accurate than conventional surgery. Many patients appear to believe navigation and robotics in Orthopaedic surgery is largely the preserve of the private sector. This study demonstrates public knowledge of such new technologies is limited and a need to inform patients of the relative merits and drawbacks of such surgery prior to their more widespread implementation

Introduction:. Following total knee arthroplasty, patients often complain of an unnatural feeling in their knee joint, which in turn limits their activities [Noble et al, CORR 2006]. To develop an implant design that recreates the motion of the natural knee, both the functional kinematics as well as the laxity of the joint need to be understood. In vitro testing that accurately quantifies the functional kinematics and laxity of the knee joint can facilitate development of implant designs that are more likely to result in a natural feeling, reconstructed knee. The objective of this study is to demonstrate that robotic in vitro testing can produce clinically relevant functional kinematics and joint laxities. Methods:. All testing was performed using a KUKA (KUKA Robotics, Augsburg, Germany) 6 degree of freedom robotic arm and a six degree of freedom load cell (ATI Industrial Automation, Apex, North Carolina, USA), attached to the arm (Figure 1). FUNCTIONAL KINEMATICS: Eight cadaveric specimens implanted with contemporary cruciate retaining implants were used for this evaluation. The functional activity, lunge, was simulated using kinematic control for flexion/extension and force-torque control for the other degrees of freedom. The inputs for the force-torque control were obtained from e-tibia data from live patients during the lunge activity [Varadarajan et al, J Biomech 2008]. At a given flexion angle, the robot moved in force-torque control to obtain the desired values within given tolerances (± 2.5N & ± 0.1 Nm). When these tolerances were met the position of femur with respect to the tibia was recorded and the knee flexed to the next level. The lunge simulation began at full extension and ended at 120 degrees of knee flexion, through 1 degree increments. The kinematic data from the contemporary CR implants were compared to in vivo kinematics of patients that were implanted with the same knee replacements performing a lunge activity [Varadarajan et al, Med Eng Phys 2009]. JOINT LAXITY: Eight native, unimplanted knees were used for this evaluation. Joint laxity of the knee joint was evaluated at 0, 30, 60, 90, and 120 degrees of knee flexion by applying various loads to the tibia and quantifying the resulting motion of the tibia. The resulting laxities were compared to various knee laxity studies in the literature. Results:. The in vitro functional kinematics correlated well with the in vivo results. Femoral external rotation and tibial varus angulation were found not be statistically different between the in vitro and in vivo results (Figure 2). The laxities measurements correlated well with reported values in the literature. Discussion:. In vitro robotic evaluations allow for a better understanding of the motion at the knee joint by simulating clinically relevant functional kinematics as well as quantifying joint laxities in the same testing system. Both of these metrics are needed to understand how the knee moves and should be used to evaluate the performance of new knee designs (Figure 3)