2016 CLINICAL RESEARCH SUMMARY

Transcription

1 216 CLINICAL RESEARCH SUMMARY

2 The following institutions have contributed research to this field of study: Hospital

3 Hospital for Joint Diseases NYU LANGONE MEDICAL CENTER

4 THE FOLLOWING VERASENSE DATA IS A COMPILATION OF BIOMECHANICAL AND CLINICAL RESEARCH PERFORMED DURING 216, EITHER IN COLLABORATION WITH OR INDEPENDENT FROM ORTHOSENSOR, INC. THE CONTENT HEREIN IS TO BE USED FOR REFERENCE ONLY.

5 Table of Contents 6 Clinical Outcomes 6 Patient Reported Satisfaction: 3-Year Multicenter Results 7 Improved Physical Therapy and Short-Term Clinical Outcomes 8 Decreased Risk of 9-Day Post-op Complications (MUA) 9 Economics 9 Cost Mitigation During Revision TKA 1 Potential for Reducing Incidence of Early Revision TKA 11 Surgical Techniques 11 Can We Really Feel a Balanced Total Knee Arthroplasty? 12 Intraoperative Load-Sensing Variability During Cemented, Posterior-Stabilized Total Knee Arthroplasty 13 Algorithmic Pie-Crusting of the MCL Guided by Sensor Technology Affects the Use of Constrained Inserts During TKA 14 Accuracy of Balancing at Total Knee Surgery Using an Instrumented Tibial Trial 15 Biomechanics 15 Intraoperative Kinematic Findings Using Sensors 16 Assessing the Predictive Capability of Specimen-Specific Knee Simulation 17 Tibiofemoral Forces for the Native and Post-Arthroplasty Knee: Relationship to Maximal Laxity Through a Functional Arc of Motion

6 CLINICAL OUTCOMES Patient Reported Satisfaction: 3-Year Multicenter Results Hospital This sensor-assisted, multicenter study cohort was prospectively assessed for concluding (3-year) patientreported outcomes. Scores were compared to existing peer-reviewed publications reporting a similar follow-up interval (2-3 years) to determine the impact of consistent TKA soft tissue balance on patient satisfaction. 129 sensor-assisted patients (quantifiably balanced) 7-question survey administered (5-point Likert scale) Literature review conducted via PRISMA guidelines SATISFIED TO VERY SATISFIED (%) YEAR PATIENT REPORTED SATISFACTION: COMPARISON OF LITERATURE Jacobs, et al. (214) Keudell, et al. (214) MANUAL ROBOTICS PSI NAVIGATION Liow, et al. (216) Nam, et al. (216) Merle-Vincent, et al. (211) Spencer, et al. (27) Liow, et al. (214) Nam, et al. (216) Martin et al. (26, CT-based) Martin et al. (26, imageless) Spencer, et al. (27) Singisetti, et al. (215) 98.3% VERASENSE ITEMIZED SATISFACTION QUESTION SCORES 98.3% of balanced, sensor-assisted patients reported being satisfied to very satisfied at 3-years post-op On average, 87% of patients reported being satisfied to very satisfied in comparative literature during the same follow-up interval 1-8 CONCLUSION: THE VERASENSE GROUP EXHIBITED THE HIGHEST REPORTED SATISFACTION AMONG CONTEMPORARY TECHNOLOGIC AND MANUAL SURGICAL MODALITIES FOR THE SAME 3-YEAR POST-OP INTERVAL. SATISFACTION SCORE (RANGE 1-5) SCORED ON LIKERT SCALE: 1 = LOWEST SCORE POSSIBLE very dissatisfied or highly disagree 5 = HIGHEST SCORE POSSIBLE very satisfied or highly agree A B C D E F G A - Overall satisfaction with surgery B - Overall pain relief after the surgery C - Overall satisfaction with the function of knee D - I can do most things I thought I would be able to do after surgery E - My pain relief is as good as expected F - I am happy with the results of my surgery G - I would have the same surgery again for the same problem 1 ) Keudell AV, Sodha S, Collins J, Minas 2 ) Jacobs CA, Christensen CP, T, Fitz W, Gomoll AH. Patient Karthikeyan T. Patient and satisfaction after primary total and intraoperative factoris influencing unicompartmental knee arthroplasty: satisfaction two to five years after an age-dependent analysis. Knee. primary total knee arthroplasty. J 214; 21: Arthroplasty. 214; 29: ) Bourne RB, Chesworth B, Davis A, Mohamed N, Charron K. Comparing patient outcomes after THA and TKA: Is there a difference? Clin Orthop Relat Res. 21; 468: ) Nam D, Nunley RM, Berend KR, Lombardi AV, Barrack RL. The impact of custom cutting guides on patient satisfaction and residual symptoms following total knee arthroplasty. Knee. 216; 23: ) Merle-Vincent F, Couris CM, Schott AM, Conrozier T, Piperno M, Mathieu P, Vignon E. /factors predicting patient satisfaction 2 years after total knee arthroplasty for osteoarthritis Joint Bone Spine. 211; 78: ) Spencer JM, Chauhan SK, Sloan K, Taylor A, Beaver RJ. Computer navigated versus conventional knee replacement. Bone Joint J. 27; 89-B: ) Singisetti K, Muthumayandi K, Abual-Rub Z, Weir D. Navigationassisted versus conventional total knee replacement: no difference in patient-reported outcomes measures (PROMs) at 1 and 2 years. Arch Orthop Trauma Surg. 215; 135: ) Liow MHL, Goh GSH, Wong MK, Chin PL, Tay DKJ, Y SJ. Robotic-assisted total knee arthroplasty may lead to improvement in quality-of-life measures: a 2-year follow-up of a prospective randomized trial. Knee Sports Surg Traumatol Arthrosc. 216; [E-pub ahead of print]. 9) Martin A, von Strempel A. Two-year outcomes of computer tomographybased and computed tomography free navigation for total knee arthroplasties. Clin Orthop Relat Res. 26; 49: OrthoSensor.com 6 VERASENSE

7 CLINICAL OUTCOMES Improved Physical Therapy and Short-Term Clinical Outcomes The use of sensorized technology in TKA may help to mitigate early soft-tissue complications and thereby improve functional outcomes over manual techniques. In order to evaluate the clinical efficacy of sensor-assisted TKA at an early follow-up interval, 114 patients were evaluated using patient reported outcomes scores and clinical range of motion (ROM) measurements. SCORE PRE-OP KSS FUNCTION 6-MONTHS MANUAL VERASENSE VERASENSE vs. MANUAL TKA BALANCING 57 consecutive sensor-assisted vs. 57 consecutive manual All cases were performed by the same surgeon with the same implant system. There were no significant cohort demographic or co-morbidity differences. VERASENSE: HIGHLY STATISTICALLY-SIGNIFICANT IMPROVEMENT ACROSS ALL OUTCOME MEASUREMENTS Faster improvement in PROMS (KSS, Oxford) Significantly higher Clinic ROM and improvement in Clinic ROM from Pre-op (P=,2 AND P<.1, RESPECTIVELY) More patients achieved active deep flexion (>115 DEG.) during physical therapy 52% VERASENSE vs. 42% MANUAL IMPROVEMENTS PRE-OP TO 6 MONTHS MANUAL VERASENSE P-VALUE KSS Pain KSS Function <.1 KSS Total <.1 Oxford Clinic ROM 9 2 <.1 CONCLUSIONS: VERASENSE HAS SHOWN STATISTICALLY SIGNIFICANT IMPROVEMENT WITH PROMS & PHYSICAL THERAPY PERFORMANCE. AN INCREASE IN PHYSICAL THERAPY PERFORMANCE AND SHORT-TERM OUTCOMES DURING RECOVERY AND REHAB SHOULD TRANSLATE TO SHORTER TREATMENTS AND LOWER OVERALL COSTS IN THE COMPLETE TKA EPISODE OF CARE. Breslauer L, Chow J. The use of intraoperative sensors significantly increases the patient-reported rate of improvement in primary total knee arthroplasty. Orthopedics. Jan 217. [Conditional Acceptance]. OrthoSensor.com 7 VERASENSE

8 CLINICAL OUTCOMES Decreased Risk of 9-Day Post-op Complications (MUA) THE USE OF ELECTRONIC SENSOR DEVICE TO AUGMENT LIGAMENT BALANCING LEADS TO A LOWER RATE OF ARTHROFIBROSIS AFTER TOTAL KNEE ARTHROPLASTY 1 Manipulation under anesthesia (MUA) is a common treatment for stiffness and arthrofibrosis post-tka. Studies show a higher degree of success when treatment is performed earlier (<3 mo.) post-tka 2 ; however, bundled payments models focusing on a 9-day episode of care may not provide reimbursement within this timefreame. MUA rates were compared for manual TKA versus VERASENSE Sensor-Assisted TKA to determine if consistent soft-tissue balance had any effect on the rates of 9-day post-op complications. MUA RATE: VERASENSE vs. NON-SENSOR 252 sensor-assisted vs. 69 non-sensor All cases were performed by the same surgeon. There were no significant cohort demographic or co-morbility differences. No difference in outcomes was seen based on implant type, age or BMI. VERASENSE: STATISTICALLY-SIGNIFICANT REDUCTION IN MUA 67% decrease in rate of MUA 62% of observed MUAs were within the 9-day post op interval OVERALL RATE OF MUA CONCLUSIONS: 4.9% NON-SENSOR P=.4 1.6% VERASENSE VERASENSE CAN MITIGATE 9-DAY POST-OP COMPLICATIONS THROUGH SOFT-TISSUE BALANCE. A DECREASE IN MUAS SHOULD REDUCE OVERALL TKA READMISSIONS AND LESSEN THE COSTS AND RISKS CURRENTLY UNDER FOCUS THROUGH CMS S COMPREHENSIVE JOINT REPLACEMENT PAYMENT PROGRAM. 1) Geller JA, Lakra A, Murtaugh T, The Use of Electronic Sensor Device to Augment Ligament Balancing Leads to a Lower Rate of Arthrofibrosis After Total Knee Arthroplasty, The Journal of Arthroplasty (217), [In press] doi: 1.116/j.arth ) Fitzsimmons SE, Vazquez EA, Bronson MJ. How to Treat the Stiff Total Knee Arthtoplasty?: A Systematic Review. Clinical Orthopaedics and Related Research. 21;468(4): OrthoSensor.com 8 VERASENSE

9 ECONOMICS Cost Mitigation During Revision TKA COST SAVINGS WHEN PLANNED TOTAL REVISION CHANGED TO PARTIAL REVISION TREATING THE LOOKS GOOD, FEELS BAD KNEE BY DIAGNOSING SOFT-TISSUE IMBALANCE Hospital for Joint Diseases NYU LANGONE MEDICAL CENTER Despite long-term success rates associated with total knee arthroplasty (TKA), a large proportion of patients continue to report dissatisfaction with their surgical outcomes. Complications such as pain, stiffness, or instability can reduce a patient s quality of life and may be attributed to soft-tissue imbalance. The cause of imbalance related complications is often difficult to diagnose, but if unresolved may lead to early total revision surgery. However, these procedures are associated with a higher risk of post-operative complications, elicit longer rehabilitation regimes, and can become a financial burden to the patient and healthcare provider. Therefore, the purpose of this study was to determine if the use of intraoperative sensors during revision TKA led to a decreased need for all-component revision. 58 REVISION TKA PROCEDURES 7 sites, 7 surgeons Patients reported with idiopathic pain, instability and/or stiffness. Radiographs showed acceptable component alignment with symmetrical joint gaps. Patients reporting pain had culture-negative aspiration findings. REVISIONS TKAs USING VERASENSE 7% SCHEDULED FOR TOTAL REVISION TOTAL r-tka PARTIAL r-tka CHANGES TO PARTIAL REVISION (N=36) 1 tibia-only, 26 polyethylene exchange ESTIMATED COST SAVINGS: $4,99 PER CASE In 36 of 58 cases, expected total revisions changed to partial revisions, which equates to a theoretical implant cost savings of $179,64. CONCLUSIONS: PRE-OP PLAN 53 VERASENSE CAN FACILITATE IMPLANT COST MITIGATION DURING TKA REVISION 1 5 PROCEDURE POST-VERASENSE AVERAGE REVISION TKA IMPLANT COSTS TOTAL REVISION TIBIA-ONLY REVISION 88% OF PLANNED TOTAL REVISIONS CHANGED TO PARTIAL REVISIONS (N=36) POLYETHYLENE EXCHANGE $6,77* $2,88 $98 * REPRESENTS 2/3 OF MEDICARE DRG POTENTIAL COST SAVINGS OF PARTIAL REVISIONS Shorter OR time, length of stay Less instrumentation, OR supplies Lower risk of complications (e.g., infection, fracture) Shorter, easier post-op rehabilitation regime Less bone stock loss, internal constraint for patient 1) Leone W, et al. Using Sensors to Evaluate Revision TKA; Treating he Looks Good; Feels Bad Knee. EC Orthopaedics 3,5 (216): OrthoSensor.com 9 VERASENSE

10 ECONOMICS Potential for Reducing Incidence of Early Revision TKA FINANCIAL BURDEN OF TKA REVISIONS: 213 MEDICARE PROVIDER ANALYSIS AND REVIEW FILE (MED PAR) 1 ANNUAL FINANCIAL BURDEN $2.7 BILLION FOR REVISION KNEE SURGERY 2 9.3% OF HOSPITALS REPORTED LOSSES ON REVISION TKA PROCEDURES COST $28,674 HOSPITAL LOSS $9,54 CMS REIMBURSEMENT $19,134 HOSPITAL AVERAGE CHARGES $73, 2,3 NET HOSPITAL LOSS PER TKA REVISION $9,54 The annual healthcare financial burden of revision TKA is estimated at $2.7 BILLION based on average hospital charges of 73 thousand dollars per case. Analysis of facility costs and Medicare reimbursements shows over 9% OF HOSPITALS LOSE MONEY ON REVISION TKA, with a loss of nearly $1, PER PROCEDURE. SENSOR-ASSISTED TKA: MULTICENTER STUDY TKA EARLY REVISION BURDEN (<2 YEARS, SOFT-TISSUE COMPLICATIONS) 12-13% REVISION BURDEN FOR TKA 4,5 APPROXIMATELY 2.6% OF TOTAL KNEE ARTHROPLASTIES RESULT IN EARLY REVISION RELATED TO SOFT-TISSUE COMPLICATIONS 4-8 (<2 Y E A R S ) VERASENSE: ONLY 1 OF 143 PATIENTS (.7%) REVISED WITHIN 2 YEARS 9 2.6% * UNITED STATES AVERAGE.7% * VERASENSE MULTICENTER STUDY * VERASENSE CANNOT PREVENT REVISION DUE TO INFECTION VERASENSE multi-center study patients showed an almost 75% LOWER RATE OF REVISION TKA compared to national averages. This reduction represents clinical and financial benefit to both patients and providers. 1 Medicare Provider Analysis and Review File. 213: Centers for Medicare & Medicaid Services Database Primary and Revision TKA. 6 Lombardi AV, Berend KR, Adams JB. Why knee replacements fail in 213: patient, surgeon, or implant? Bone Joint J. 214;96-B(11 Supple A): Bhandari M, Smith J, Miller L, et al. Clinical and economic burden of revision knee arthroplasty. Clin Med Insights Arthritis Musculoskelet Disord : Schroer WC, Berend KR, Lombardi AV, et al. Why are total knees failing today? Etiology of total knee revision in 21 and 211. J Arthroplasty. 213;28(8 Suppl): Lavernia C, Lee DJ, Hernandez VH. The increasing financial burden of knee revision surgery in the United States. Clin Orthop Relat Res. 26; 446: Sharkey PF, Lichstein PM, Shen C, et al. Why are total knee arthroplasties failing today has anything changed after 1 years? J Arthroplasty. 214;29(9): Bozic K, Kurtz S, Lau E, et al. The epidemiology of revision total knee arthroplasty in the united states. Clin Orthop Relat Res : OrthoSensor Multicenter Evaluation. Pending Publication. Data on file at OrthoSensor, Inc. 5 Thiele K, Perka C, Matziolis G, Mayr HO, Sostheim M, Hube R. Current failure mechanisms after knee arthroplasty have changed: polyethylene wear is less common in revision surgery. J Bone Join Surg. 215; 97(9): OrthoSensor.com 1 VERASENSE

11 SURGICAL TECHNIQUES Can We Really Feel a Balanced Total Knee Arthroplasty? Intraoperative sensors were used in blinded (control) and unblinded cohorts to compare the feel of an experienced surgeon to sensor-generated data in order to evaluate appropriate TKA balance through a range of motion. A total of 22 primary TKA patients, in 2 groups (12 manual, gap-balanced; 1 VERASENSE, sensor-assisted), were evaluated for any differences in mediolateral loading and soft-tissue release type performed. Intraoperative sensors were used in both groups. The surgeon (3 years of experience) was blinded to the sensor data in the manual group, and was able to use the sensor data in the sensor-assisted group. LOADING (LBF.) COMPARTMENTAL LOADING AVERAGES IN MANUAL AND VERASENSE COHORTS Manual (Blinded) MEDIAL 1 LATERAL 1 VERASENSE (Unblinded) MEDIAL 45 LATERAL 45 MEDIAL 9 LATERAL 9 DEGREES OF FLEXION CHARACTERISTIC COMPARTMENTAL LOADING EXAMPLES IN MANUAL AND VERASENSE COHORTS The VERASENSE cohort exhibited lower overall loading, in both the medial and lateral compartments, than the manual group. Intercompartmental loading through the range of motion was significantly more symmetrical in the VERASENSE group than the manual group. MANUAL (BLINDED) CONCLUSION: SENSOR-ASSISTED SURGERY PROVIDES OBJECTIVE DATA THAT MAY ASSIST SURGEONS IN DECREASING THE INCIDENCE OF OUTLIERS IN LOADING ACROSS THE KNEE JOINT. VERASENSE (UNBLINDED) DEGREES OF FLEXION COMPARISON OF COMPARTMENT LOAD AT VARIOUS DEGREES IN RANGE OF MOTION IN MEDIAL AND LATERAL COMPARTMENTS VERASENSE COHORT, MEAN (RANGE) (SD) MANUAL COHORT MEAN (RANGE) (SD) P VALUE MEDIAL COMPARTMENT (16-44) (8) 23.1 (9-38) (8) 2.4 (7-38) (8) 79.3 (12-228) (62) 77.2 (6-177) (51) 55.4 (4-159) (48) LATERAL COMPARTMENT (-38) (1) 13.3 (4-25) (7) 16.1 (7-38) (8) 27.6 (-12) (37) 31.3 (-99) (38) 28.4 (-73) (29) SD, STANDARD DEVIATION 1) Elmallah RK, Mistry JB, Cherian JJ, Chugato M, Bhave A, Roche MW, Mont MA. J Arthroplasty. 216; 31: OrthoSensor.com 11 VERASENSE

12 SURGICAL TECHNIQUES Intraoperative Load-Sensing Variability During Cemented, Posterior-Stabilized Total Knee Arthroplasty To understand the utility of using sensing devices when evaluating pre- and post-trialing load conditions during TKA. Kinematic data from 54 TKA surgeries was captured and analyzed. Specific conditions evaluated include: loading conditions before and after cementation, and any changes to the state of balance between trialing and final implantation. CONCLUSION: THE USE OF INTRAOPERATIVE SENSORS PROVIDES OBJECTIVE FEEDBACK ABOUT THE BEHAVIOR OF EACH COMPARTMENT, INDEPENDENTLY. THIS MAY ALLOW SURGEONS TO CORRECT RESIDUAL IMBALANCE IN AVOIDANCE OF FUTURE POST- OPERATIVE COMPLICATIONS. There was agreement between loading conditions, during trialing and final implantation, in the medial compartment only. The lateral compartment exhibited higher degrees of variability between the trialing and final implantation phase. MEDIAL COMPARTMENT LOADS AT 1 DEGREES OF FLEXION 25 LATERAL COMPARTMENT LOADS AT 1 DEGREES OF FLEXION 25 FINAL LOAD (LBS) FINAL LOAD (LBS) TRIAL LOAD (LBS) TRIAL LOAD (LBS) MEDIAL COMPARTMENT LOADS AT 45 DEGREES OF FLEXION LATERAL COMPARTMENT LOADS AT 45 DEGREES OF FLEXION FINAL LOAD (LBS) TRIAL LOAD (LBS) FINAL LOAD (LBS) TRIAL LOAD (LBS) MEDIAL COMPARTMENT LOADS AT 9 DEGREES OF FLEXION LATERAL COMPARTMENT LOADS AT 9 DEGREES OF FLEXION 25 3 FINAL LOAD (LBS) TRIAL LOAD (LBS) FINAL LOAD (LBS) TRIAL LOAD (LBS) 1) Nodzo SC, Franceschini V, Gonzalez Della Valle A. Intraoperative load-sensing variability during cemented, posterior-stabilized total knee arthroplasty. J Arthroplasty. 216 [E-pub ahead of print]. OrthoSensor.com 12 VERASENSE

13 SURGICAL TECHNIQUES Algorithmic Pie-Crusting of the MCL Guided by Sensor Technology Affects the Use of Constrained Inserts During TKA To determine if targeted, algorithmic soft tissue release, performed with the use of intraoperative sensors, is effective and has any effect on the need for mechanical implant constraint. This study evaluated 75 sensor-assisted TKAs versus 225 manual TKAs. The authors compared the clinical efficacy of sensor-assisted TKA using a pie-crusting technique to release the medial soft-tissue sleeve. The authors also evaluated the incidence of using constrained inserts in sensor-assisted versus manual TKA. With a 19-gauge needle, the surgeon uses a pie-crusting technique to release ligament fibers of the MCL There was a significant decrease in the use of constrained inserts in the sensor-assisted group versus the manual group 8% VERASENSE VS. 18% MANUAL (P =.2) Sensor-assisted TKA showed similar functional improvement in ROM and KSS scores, postoperatively. CONCLUSIONS: GIVEN SIMILAR IMPROVEMENT IN ROM/KSS, SENSOR-ASSISTED TKA IS AS SAFE AND EFFECTIVE AS TRADITIONAL TECHNIQUES. Following MCL release, the mediolateral differential exhibits symmetric balance USE OF CONSTRAINED INSERTS IN THE STUDY GROUP AND CONTROL GROUP, BY PREOPERATIVE VARUS DEFORMITY ADDITIONAL CONCLUSION: THE DECREASED USE OF CONSTRAINED INSERTS IN THE SENSOR- ASSISTED GROUP MAY LEAD TO DECREASED OPERATIVE SPENDING. % CONSTRAINED INSERT USAGE P=.49 MILD P=.8 MODERATE P=.1 P=.3 Manual VERASENSE P=.2 MARKED SEVERE TOTAL 1) Mehdikhani KG, Moreno BM, Reid JJ, de Paz Nieves A, Lee YY, Gonzalez Della Valle A. An algorithmic, pie-crusting medial soft-tissue release reduces the need for constrained inserts in patients with severe varus deformity undergoing total knee arthroplasty. J Arthroplasty. 216 [E-pub ahead of print] OrthoSensor.com 13 VERASENSE

14 SURGICAL TECHNIQUES Accuracy of Balancing at Total Knee Surgery Using an Instrumented Tibial Trial Hospital for Joint Diseases NYU LANGONE MEDICAL CENTER To understand the effect of surgical corrections on intercompartmental balance during primary TKA. 11 TKA cases were performed with the use of sensors to display intra-articular loading values in the medial and lateral compartment, in real-time. The goal of each procedure was to equalize loads in the medial and lateral compartment (load distribution ratio:.5). The most common corrections to achieve balance were to release the posterolateral corner, posteromedial capsule, and MCL. After balancing with sensor assistance, the mean load distribution ratio was.52. In a majority of cases, -2 corrections were required to achieve balance. CONCLUSION: THE USE OF SENSORS IN TKA CAN ENHANCE BALANCING ACCURACY AND RESULT CONSISTENCY WITH A RELATIVELY MINIMUM NUMBER OF ADJUSTMENTS. MEDIAL/TOTAL CONTACT FORCE MEDIAL/TOTAL CONTACT FORCE FIGURE 1 INITIAL FORCE RATIO (PRE-BALANCING) FLEXION ANGLE FIGURE 2 FINAL FORCE RATIO (POST-BALANCING) FLEXION ANGLE FIGURE 1-2 Ratio of medial to total (medial + lateral) intercompartmental forces before and after balancing. The standard deviation was considerably reduced after balancing. CHANGES IN TIBIOFEMORAL FORCES IN EXTENSION BEFORE AND AFTER THE MOST COMMON SURGICAL CORRECTIONS CORRECTION AVERAGE MEDIAL-TO-TOTAL FORCE RATIO BEFORE AVERAGE MEDIAL-TO-TOTAL FORCE RATIO AFTER SIGNIFICANCE Posterolateral corner release Posteromedial capsule release Medial collateral ligament release.22 ±.23.7 ± ±.14.4 ± ± ±.16 P.1 P.1 P.1 TOTAL FORCE (N) BEFORE TOTAL FORCE (N) AFTER Increase in tibial liner thickness ± ±.16 P.1 1) Meere PA, Schneider SM, Walker PS. Accuracy of balancing at total knee surgery using an instrumented tibial trial. J Arthorplasty. 216; 31: OrthoSensor.com 14 VERASENSE

15 BIOMECHANICS Intraoperative Kinematic Findings Using Sensors Hospital The authors sought to learn how specific corrections including bony corrections and ligament releases affect in-vivo loading and dynamic kinematic signatures of the intraoperative knee. In a multicenter study, 129 patients underwent primary, sensor-assisted TKA. Intraoperative loading behavior was captured, both pre- and post-correction, in the medial and lateral compartments. Type of bony correction or ligament release, with corresponding loading response, was also captured. Loading release type and effect were input into a regression analysis to determine how intra-articular loading values were affected by individual releases. CONCLUSIONS: WHILE BALANCING WITH THE SENSOR, OVERALL INTRA-ARTICULAR LOADING DECREASED, AND THE MEDIAL-LATERAL LOADING SYMMETRY INCREASED. PARTICIPATING SURGEONS WERE ABLE TO MAKE TARGETED RELEASES TO MANIPULATE A WIDE VARIETY OF STRUCTURES ON THE MEDIAL AND LATERAL SIDES. LOADING (LBF.) VARUS KNEE LOADING MEDIAL COMPARTMENT EXTENSION MID-FLEXION FLEXION Pre-Release Post-Release On average, 2.5 corrections (up to 8) were made in order to achieve balance. (< 15 LBF. OF MEDIOLATERAL DIFF) After balancing, a majority of patients displayed the heaviest loading on the medial side (61.9%). The difference between pre- and post-correction loading included: MORE SYMMETRICAL LOADING between the medial and lateral compartments LOWER LOADING OVERALL The most significant intraoperative corrections that contributed to change in overall loading conditions were: releasing the pes anserine, releasing the MCL, shim size increase, and bony varus correction The line graphs indicate the loading values, in the medial and lateral compartments, through the range of motion, and in pre- and post-correction states. LOADING (LBF.) LOADING (LBF.) LOADING (LBF.) LATERAL COMPARTMENT Pre-Release Post-Release EXTENSION MID-FLEXION FLEXION VALGUS KNEE LOADING MEDIAL COMPARTMENT Pre-Release Post-Release EXTENSION MID-FLEXION FLEXION LATERAL COMPARTMENT Pre-Release Post-Release EXTENSION MID-FLEXION FLEXION Gustke et al. A Targeted Approach to Ligament Balance, J Arthroplasty (Accepted, In Press) OrthoSensor.com 15 VERASENSE

16 BIOMECHANICS Assessing the Predictive Capability of Specimen-Specific Knee Simulation To assess the predictive capability of two simulated knees using comparisons with experimentally determined trends found after systematic removal of key tissues. Four cadaveric specimens (8 knees) were implanted with TKA components. In-vivo laxity testing was performed at 1 with combined anteroposterior, varus-valgus moment, and internal-external forces applied. The authors evaluated the relative accuracy of intraoperative sensor output, and simulated modelling, to in-vivo conditions. Conditions included knees with: fully intact ligaments, PCL release, MCL release, and popliteus release, successively. MODEL EXPERIMENT LAT. LOAD (N) LAT. LOAD (N) RELEASED SPECIMEN 2. PCL RELEASE Intact Exp. Release Exp ANT POS VAR VAL IR ER LOADING STATE Intact Model Release Model ANT POS VAR VAL IR ER LOADING STATE RELEASED Medial Lateral Kinematics (JCS) Contact Kinematics (JCS) Contact There was favorable agreement between the sensor output and simulation, both of which accurately described the joint kinematics for each scenario. CONCLUSION: SENSOR-ASSISTANCE DURING TKA MAY PROVIDE SURGEONS WITH AN ACCURATE DEPICTION OF NON-NATIVE INTRA-ARTICULAR JOINT KINEMATICS. MED. LOAD (N) MED. LOAD (N) SPECIMEN 4. smcl RELEASE Intact Exp. Release Exp ANT POS VAR VAL IR ER LOADING STATE Intact Model Release Model ANT POS VAR VAL IR ER LOADING STATE [Manuscript currently under peer review] OrthoSensor.com 16 VERASENSE

17 BIOMECHANICS Tibiofemoral Forces for the Native and Post Arthroplasty Knee: Relationship to Maximal Laxity Through a Functional Arc of Motion The authors used intraoperative sensors to define force and laxity conditions in a CR knee design in order to quantify the kinematic behavior of the CR femoral single-radius knee. 8 cadaveric specimens (loaded). Computer navigation was combined with sensor data to define laxity and tibiofemoral contact force during manual laxity testing. Inverse relationships were observed between laxity and contact force loading. There was a roll-forward inclination observed with respect to the tibiofemoral contact point location when the knee was taken into flexion. Change in the laxity of ligaments was shown to be significant past: 3 in the coronal plane 6 in the rotary plane RELATIVE INTERNAL AND EXTERNAL ROTATION LAXITY AND FORCE BY ANGLE, CR-TKR CONCLUSION: INTRAOPERATIVE SENSORS MAY BE MORE SENSITIVE THAN MANUAL TECHNIQUES WHEN DEPICTING CHANGES IN LOADING BEHAVIOR, THROUGH THE RANGE OF MOTION, DURING TKA. RELATIVE LAXITY (%) Laxity Load LOAD (LBS) ANGLE 8 1 1) Manning WA, Ghosh Kanishka, Blain A, Longstaff L, Deehan DJ. Tibiofemoral forces for the native and post-arthroplasty knee: relationship to maximal laxity through functional arc of motion. Knee Sports Surg Traumatol Arthrosc. 216 [E-pub ahead of print]. OrthoSensor.com 17 VERASENSE

18 Notes OrthoSensor.com 18 VERASENSE

19 Notes OrthoSensor.com 19 VERASENSE

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