Since the COVID-19 pandemic of 2020, there has been a marked rise in the use of telemedicine to evaluate patients following total knee arthroplasty (TKA). Telemedicine is helpful to maintain patient contact, but it cannot provide objective functional TKA data. External monitoring devices can be used, but in the past have had mixed results due to patient compliance and data continuity, particularly for monitoring over numerous years. This novel stem is a translational product with an embedded sensor that can remotely monitor patient activity following TKA The Canturio™ TE∗ System (Canary Medical) functions structurally as a tibial extension for the Persona® cemented tibial plate (Zimmer Biomet). The stem is instrumented with internal motion sensors (3-D accelerometer and gyroscope) and telemetry that collects and transmits kinematic data. Raw data is converted by analytics into clinically relevant gait metrics using a proprietary algorithm. The Canturio™ TE∗ will monitor the patient's gait daily for the first year and then with lower frequency thereafter to conserve battery power enabling the potential for 20 years of longitudinal data collection and analysis. A base station in the OR activates the device and links the stem and data to the patient. A base station in the patient's home collects and uploads data to the Cloud Based Canary Data Management Platform (Canary Medical). The Canary Cloud is structured as an FDA regulated and HIPPA-compliant database with cybersecurity protocols integrated into the architecture. A third base station is an accessory used in the health care professional's office to perform an on-demand gait analysis of a patient. A dashboard allows the health care professional and patient to monitor objective data of the patient's activity and progress post treatment.PROBLEM
SOLUTION
Medical comorbidities are a critical factor in the decision-making process for operative management and risk-stratification. The Hierarchical Condition Categories (HCC) risk adjustment model is a powerful measure of illness severity for patients treated by surgeons. The HCC is utilized by Medicare to predict medical expenditure risk and to reimburse physicians accordingly. HCC weighs comorbidities differently to calculate risk. This study determines the prevalence of medical comorbidities and the average HCC score in Medicare patients being evaluated by neurosurgeons and orthopaedic surgeon, as well as a subset of academic spine surgeons within both specialities, in the USA. The Medicare Provider Utilization and Payment Database, which is based on data from the Centers for Medicare and Medicaid Services’ National Claims History Standard Analytic Files, was analyzed for this study. Every surgeon who submitted a valid Medicare Part B non-institutional claim during the 2013 calendar year was included in this study. This database was queried for medical comorbidities and HCC scores of each patient who had, at minimum, a single office visit with a surgeon. This data included 21,204 orthopaedic surgeons and 4,372 neurosurgeons across 54 states/territories in the USA.Aims
Methods
Initial stability of cementless total knee arthroplasty (TKA) tibial trays is necessary to facilitate biological fixation. Previous experimental and computational studies describe a dynamic loading micromotion test used to evaluate the initial stability of a design. Experimental tests were focused on cruciate retaining (CR) designs and walking gait loading. A FEA computational study of various constraints and activities found CR designs during walking gait experienced the greatest micromotion. This experimental study is a continuation of testing performed on CR and walking gait to include a PS design and stair descent activity. The previously described experimental method employed robotic loading informed by a custom computational model of the knee. Different TKA designs were virtually implanted into a specimen specific model of the knee. Activities were simulated using in-vivo loading profiles from instrumented tibia implants. The calculated loads on the tibia were applied in a robotic test. Anatomically designed cementless tibia components were implanted into a bone surrogate. Micromotion of the tray relative to the bone was measured using digital image correlation at 10 locations around the tray. Three PS and three CR samples were dynamically loaded with their respective femur components with force and moment profiles simulating walking gait and stair descent activities. Periods of walking and stair descent cycles were alternated for a total of 2500 walking cycles and 180 stair descent cycles. Micromotion data was collected intermittently throughout the test and the overall 3D motion during a particular cycle calculated. The data was normalized to the maximum micromotion value measured throughout the test. The experimental data was evaluated against previously reported computational finite element model of the micromotion test.Introduction
Methods
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. 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.Purpose
Method
Subjects having a posterior cruciate ligament sacrificing (PCLS) mobile bearing TKA seem to experience less translation during gait, but often achieve less weight-bearing flexion. More recently, posterior stabilisation has been added to PCLS mobile bearing TKA, hoping to increase flexion. Therefore, the objective of this multi-center study was to determine the in vivo kinematics for subjects implanted with a mobile bearing PS TKA that attempts to maintain high contact area. Subjects with 10 TKA from 2 surgeons were asked to perform maximum weight-bearing flexion (deep knee bend (DKB)) and gait while under fluoroscopic surveillance. During weight bearing flexion, the 3-D kinematics of the TKA were determined by analyzing fluoroscopic images in the sagittal plane at 30 degree increments. Fluoroscopic images taken in the frontal plane from four increments during the stance phase of gait were analyzed. The average weight-bearing flexion was 116 degrees and the average medial and lateral anteriorposterior (AP) translation was posterior with −1.9 mm and −5.4 mm, respectively, from full extension to maximum weight-bearing flexion. The average femorotibial axial rotation from full extension to maximum weight-bearing flexion was 3.9 degrees. During the stance phase of treadmill gait, patients experienced 0.8 mm (0.1 mm to 2.3 mm, SD=0.8 mm) of “pure” mediolateral translation of the femur relative to the tibia. The femorotibial axial rotation was 4.6 degrees from heel-strike to toe-off (Table 3). The posterior femoral rollback and axial rotation patterns were similar to the normal knee, albeit experiencing less overall motion. More noticeably, subjects in this study experienced a significantly greater weight-bearing flexion than previous subjects analyzed with a mobile bearing PCLS TKA and more reproducible “fan-like” patterns, where the lateral condyle rolled greater posteriorly than the medial condyle.
At present, long-term follow-up studies are used to assess the performance and longevity of an implant, but the downside is that designers must wait 5–10 years before they receive this feedback. Therefore, the objective of this study was to develop a theoretical simulator that will allow for prediction of kinematic patterns based on implant shape and prediction of implant longevity based on the implant’s ability to adapt to in vivo conditions. A model of the normal lower leg, including muscles and all ligament structures, was developed using Kane’s theory of dynamics. All muscles and ligaments were modeled as distributed loads and included wrapping points to follow the true path of soft-tissue structures. Currently, two activities are available to the user: leg extension and deep flexion. 3D shapes, pertaining to the implant designs are input to the model. A validation of the model was conducted using an initial force prediction for each muscle. The predicted kinematics were compared to a library of in vivo kinematics from over 2000 knees obtained using fluoroscopy and a 3-D model fitting technique. If the kinematic patterns from the model were incorrect, an optimization feedback algorithm induced a change in the muscle force. This process continued until the proper muscle force profiles were determined. Then, using muscle forces which achieve observed motion in TKA previously implanted and analyzed, evaluation of various new implant designs could be assessed. Altering designs or constraints in TKA lead to quite different kinematic profiles, even when the same muscle force profiles are used. Further research needs to be conducted using more design profiles before multiple implant designs could be evaluated and compared.
