scholarly journals Kinetic Sensors for Ligament Balance and Kinematic Evaluation in Anatomic Bi-Cruciate Stabilized Total Knee Arthroplasty

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5427
Author(s):  
Luigi Sabatini ◽  
Francesco Bosco ◽  
Luca Barberis ◽  
Daniele Camazzola ◽  
Alessandro Bistolfi ◽  
...  
Keyword(s):  
Full Range ◽  
Lateral Compartment ◽  
Differential Pressure ◽  
Sensor Technology ◽  
Consecutive Series ◽  
Joint Kinetics ◽  
Radiological Parameters ◽  
Ligament Balance ◽  
Medial Pivot ◽  
Kinematic Evaluation

Sensor technology was introduced to intraoperatively analyse the differential pressure between the medial and lateral compartments of the knee during primary TKA using a sensor to assess if further balancing procedures are needed to achieve a “balanced” knee. The prognostic role of epidemiological and radiological parameters was also analysed. A consecutive series of 21 patients with primary knee osteoarthritis were enrolled and programmed for TKA in our unit between 1 September 2020 and 31 March 2021. The VERASENSE Knee System (OrthoSensor Inc., Dania Beach, FL, USA) has been proposed as an instrument that quantifies the differential pressure between the compartments of the knee intraoperatively throughout the full range of motion during primary TKA, designed with a J-curve anatomical femoral design and a PS “medially congruent” polyethylene insert. Thirteen patients (61.90%) showed a “balanced” knee, and eight patients (38.10%) showed an intra-operative “unbalanced” knee and required additional procedures. A total of 13 additional balancing procedures were performed. At the end of surgical knee procedures, a quantitatively balanced knee was obtained in all patients. In addition, a correlation was found between the compartment pressure of phase I and phase II at 10° of flexion and higher absolute pressures were found in the medial compartment than in the lateral compartment in each ROM degree investigated. Moreover, those pressure values showed a trend to decrease with the increase in flexion degrees in both compartments. The “Kinetic Tracking” function displays the knee’s dynamic motion through the full ROM to evaluate joint kinetics. The obtained kinetic traces reproduced the knee’s medial pivot and femoral rollback, mimicking natural knee biomechanics. Moreover, we reported a statistically significant correlation between the need for soft tissue or bone resection rebalancing and severity of the initial coronal deformity (>10°) and a preoperative JLCA value >2°. The use of quantitative sensor-guided pressure evaluation during TKA leads to a more reproducible “balanced” knee. The surgeon, evaluating radiological parameters before surgery, may anticipate difficulties in knee balance and require those devices to achieve the desired result objectively.

Evaluation of Femoral–Tibial Flexion Gap in Total Knee Arthroplasty with Everted or Lateralized Patella

2018 ◽  
Vol 32 (10) ◽  
pp. 1028-1032 ◽  
Author(s):  
Michele Malavolta ◽  
Andrea Cochetti ◽  
Silvio Mezzari ◽  
Alberto Residori ◽  
Gianpietro Lista
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Rotation Angle ◽  
External Rotation ◽  
Lateral Displacement ◽  
Lateral Compartment ◽  
Consecutive Series ◽  
Flexion Gap ◽  
Medial Pivot ◽  
Total Knee

AbstractIntraoperative patellar position (eversion, lateralization, or in situ) influences the ligamentous balancing in knee flexion and thereby the correct positioning of the femoral component during total knee arthroplasty. The correct ligament balancing is crucial when, as in our experience, prostheses with medial pivot design are used. It was shown that the flexion gap in the normal knee is not rectangular and that the lateral compartment is significantly slacker than the medial. Therefore, to obtain a correct kinematics of a medial pivot anatomical prosthesis, it is essential to recreate an anatomical flexion gap slacker in the lateral compartment. We conducted a prospective study on a consecutive series of 87 total knee prostheses. The objective of this study is to evaluate the femoral external rotation angle in each patient with everted patella as well as with pure subluxated patella. The purpose of this study is to offer guidance about the optimal femoral rotation angle to achieve best outcomes of a knee replacement. The evaluation was done using an instrument developed by Medacta International (Switzerland) with our direct collaboration (Tensor, Medacta, Switzerland) and standardizing the basic conditions of each patient (knee 90 degrees flexed, medial transquadricipital surgical access, lateral displacement of the patella, tourniquet inflated at 250 mm Hg, spinal anesthesia). Each group was subdivided into subgroups according to gender, preoperative varus or valgus deformity, and patellar height. Our study advises against evaluating the flexion gap with everted patella due to high risk of underestimation of the lateral compartment laxity (differences up to + 3 degrees with pure subluxated patella compared with everted patella).

Biomechanical Comparison of Kinematic and Mechanical Knee Alignment Techniques in a Computer Simulation Medial Pivot Total Knee Arthroplasty Model

2021 ◽  
Author(s):  
Young Dong Song ◽  
Shinichiro Nakamura ◽  
Shinichi Kuriyama ◽  
Kohei Nishitani ◽  
Hiromu Ito ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Flexion ◽  
External Rotation ◽  
Knee Kinematics ◽  
Lateral Compartment ◽  
Contact Stresses ◽  
Contact Forces ◽  
Medial Compartment ◽  
Tibial Insert ◽  
Medial Pivot

AbstractSeveral concepts may be used to restore normal knee kinematics after total knee arthroplasty. One is a kinematically aligned (KA) technique, which restores the native joint line and limb alignment, and the other is the use of a medial pivot knee (MPK) design, with a ball and socket joint in the medial compartment. This study aimed to compare motions, contact forces, and contact stress between mechanically aligned (MA) and KA (medial tilt 3° [KA3] and 5° [KA5]) models in MPK. An MPK design was virtually implanted with MA, KA3, and KA5 in a validated musculoskeletal computer model of a healthy knee, and the simulation of motion and contact forces was implemented. Anteroposterior (AP) positions, mediolateral positions, external rotation angles of the femoral component relative to the tibial insert, and tibiofemoral contact forces were evaluated at different knee flexion angles. Contact stresses on the tibial insert were calculated using finite element analysis. The AP position at the medial compartment was consistent for all models. From 0° to 120°, the femoral component in KA models showed larger posterior movement at the lateral compartment (0.3, 6.8, and 17.7 mm in MA, KA3, and KA5 models, respectively) and larger external rotation (4.2°, 12.0°, and 16.8° in the MA, KA3, and KA5 models, respectively) relative to the tibial component. Concerning the mediolateral position of the femoral component, the KA5 model was positioned more medially. The contact forces at the lateral compartment of all models were larger than those at the medial compartment at >60° of knee flexion. The peak contact stresses on the tibiofemoral joint at 90° and 120° of knee flexion were higher in the KA models. However, the peak contact stresses of the KA models at every flexion angle were <20 MPa. The KA technique in MPK can successfully achieve near-normal knee kinematics; however, there may be a concern for higher contact stresses on the tibial insert.

scholarly journals Evaluation of SWIR Crop Residue Bands for the Landsat Next Mission

2021 ◽  
Vol 13 (18) ◽  
pp. 3718
Author(s):  
Wells Dean Hively ◽  
Brian T. Lamb ◽  
Craig S. T. Daughtry ◽  
Guy Serbin ◽  
Philip Dennison ◽  
...  
Keyword(s):  
Vegetation Cover ◽  
Crop Residue ◽  
Full Range ◽  
Regional Scale ◽  
Atmospheric Correction ◽  
Agricultural Landscapes ◽  
Hyperspectral Data ◽  
Sensor Technology ◽  
Landsat 8 ◽  
Green Vegetation

This research reports the findings of a Landsat Next expert review panel that evaluated the use of narrow shortwave infrared (SWIR) reflectance bands to measure ligno-cellulose absorption features centered near 2100 and 2300 nm, with the objective of measuring and mapping non-photosynthetic vegetation (NPV), crop residue cover, and the adoption of conservation tillage practices within agricultural landscapes. Results could also apply to detection of NPV in pasture, grazing lands, and non-agricultural settings. Currently, there are no satellite data sources that provide narrowband or hyperspectral SWIR imagery at sufficient volume to map NPV at a regional scale. The Landsat Next mission, currently under design and expected to launch in the late 2020’s, provides the opportunity for achieving increased SWIR sampling and spectral resolution with the adoption of new sensor technology. This study employed hyperspectral data collected from 916 agricultural field locations with varying fractional NPV, fractional green vegetation, and surface moisture contents. These spectra were processed to generate narrow bands with centers at 2040, 2100, 2210, 2260, and 2230 nm, at various bandwidths, that were subsequently used to derive 13 NPV spectral indices from each spectrum. For crop residues with minimal green vegetation cover, two-band indices derived from 2210 and 2260 nm bands were top performers for measuring NPV (R2 = 0.81, RMSE = 0.13) using bandwidths of 30 to 50 nm, and the addition of a third band at 2100 nm increased resistance to atmospheric correction residuals and improved mission continuity with Landsat 8 Operational Land Imager Band 7. For prediction of NPV over a full range of green vegetation cover, the Cellulose Absorption Index, derived from 2040, 2100, and 2210 nm bands, was top performer (R2 = 0.77, RMSE = 0.17), but required a narrow (≤20 nm) bandwidth at 2040 nm to avoid interference from atmospheric carbon dioxide absorption. In comparison, broadband NPV indices utilizing Landsat 8 bands centered at 1610 and 2200 nm performed poorly in measuring fractional NPV (R2 = 0.44), with significantly increased interference from green vegetation.

Functional alignment achieves soft tissue balance in total knee arthroplasty as measured with quantitative sensor-guided technology

2021 ◽  
pp. 1-8
Author(s):  
Justin S. Chang ◽  
Babar Kayani ◽  
Charles Wallace ◽  
Fares S. Haddad
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
Lateral Compartment ◽  
Soft Tissue Balance ◽  
Sensor Technology ◽  
Soft Tissue Envelope ◽  
Total Knee ◽  
Compartment Pressures

Aims Total knee arthroplasty (TKA) using functional alignment aims to implant the components with minimal compromise of the soft-tissue envelope by restoring the plane and obliquity of the non-arthritic joint. The objective of this study was to determine the effect of TKA with functional alignment on mediolateral soft tissue balance as assessed using intraoperative sensor-guided technology. Methods This prospective study included 30 consecutive patients undergoing robotic-assisted TKA using the Stryker PS Triathlon implant with functional alignment. Intraoperative soft tissue balance was assessed using sensor-guided technology after definitive component implantation; soft tissue balance was defined as intercompartmental pressure difference (ICPD) of < 15 psi. Medial and lateral compartment pressures were recorded at 10°, 45°, and 90° of knee flexion. This study included 18 females (60%) and 12 males (40%) with a mean age of 65.2 years (SD 9.3). Mean preoperative hip-knee-ankle deformity was 6.3° varus (SD 2.7°). Results TKA with functional alignment achieved balanced medial and lateral compartment pressures at 10° (25.0 psi (SD 6.1) vs 23.1 psi (SD 6.7), respectively; p = 0.140), 45° (21.4 psi (SD 5.9) vs 20.6 psi (SD 5.9), respectively; p = 0.510), and 90° (21.2 psi (SD 7.1) vs 21.6 psi (SD 9.0), respectively; p = 0.800) of knee flexion. Mean ICPD was 6.1 psi (SD 4.5; 0 to 14) at 10°, 5.4 psi (SD 3.9; 0 to 12) at 45°, and 4.9 psi (SD 4.45; 0 to 15) at 90° of knee flexion. Mean postoperative limb alignment was 2.2° varus (SD 1.0°). Conclusion TKA using the functional alignment achieves balanced mediolateral soft tissue tension through the arc of knee flexion as assessed using intraoperative pressure-sensor technology. Further clinical trials are required to determine if TKA with functional alignment translates to improvements in patient satisfaction and outcomes compared to conventional alignment techniques.

scholarly journals Dynamic decompression of the lateral femoral cutaneous nerve to treat meralgia paresthetica: technique and results

2019 ◽  
Vol 131 (5) ◽  
pp. 1552-1560
Author(s):  
Martijn J. A. Malessy ◽  
Job Eekhof ◽  
Willem Pondaag
Keyword(s):  
Full Range ◽  
Cutaneous Nerve ◽  
Lateral Femoral Cutaneous Nerve ◽  
Sartorius Muscle ◽  
Symptom Duration ◽  
Consecutive Series ◽  
Meralgia Paresthetica ◽  
Inferior Aspect ◽  
Femoral Cutaneous Nerve

OBJECTIVEThe results of lateral femoral cutaneous nerve (LFCN) decompression to treat idiopathic meralgia paresthetica (iMP) vary widely. Techniques to decompress the LFCN differ, which may affect outcome, but in MP it is unknown to what extent. The authors present a new technique using dynamic decompression and discuss the outcomes.METHODSA retrospective cohort study was performed in a consecutive series of 19 cases. The goal of decompression was pain relief and recovery of sensation. The plane ventral to the LFCN was decompressed by cutting the fascia lata and the inferior aspect of the inguinal ligament. The plane dorsal to the LFCN was decompressed by cutting the fascia of the sartorius muscle. Subsequently, the thigh was brought in full range of flexion and extension/abduction. The authors identified and additionally cut fibers that tightened and caused compression at various locations of the LFCN during movement in all patients, referring to this technique as dynamic decompression. Postoperatively, an independent neurologist scored pain and sensation on a 4-point scale: completely resolved, improved, not changed, or worsened. Patients scored their remaining pain or sensory deficit as a percentage of the preoperative level. Statistical assessment was done using ANOVA to assess the association between outcome and duration of preoperative symptoms, BMI, and length of follow-up.RESULTSIn 17 of the 19 cases (89%), the pain and/or paresthesia completely resolved. Patients in the remaining 2 cases (11%) experienced 70% and 80% reduction in pain. Sensation completely recovered in 13 of the 19 cases (69%). In 5 of the 19 cases (26%) sensation improved, but an area of hypesthesia remained. Four of these 5 patients indicated a sensory improvement of more than 75%, and the remaining patient had 50% improvement. Sensation remained unchanged in 1 case (5%) with persisting hypesthesia and mild hyperesthesia. There was no significant impact of preoperative symptom duration, BMI, and length of follow-up on postoperative outcome.CONCLUSIONSDynamic decompression of the LFCN is an effective technique for the treatment of iMP. Most patients become completely pain free and sensation recovers considerably.

scholarly journals Design of a Cable-Driven Actuator for Pronation and Supination of the Forearm to Integrate an Active Arm Orthosis

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 4
Author(s):  
Eduardo A. F. Dias ◽  
Rafhael M. de Andrade
Keyword(s):  
Activities Of Daily Living ◽  
Range Of Motion ◽  
Daily Living ◽  
Full Range ◽  
Weight Ratio ◽  
Design Stage ◽  
Open Ring ◽  
Kinematic Evaluation ◽  
Heavy Structure ◽  
Digital Prototype

The pronation/supination of the forearm are important movements to properly accomplish the activities of daily living. While several exoskeletons have been proposed for the rehabilitation of the arm, few of them have actively implemented the movements of pronation/supination. Often, the addition of this degree of freedom to the mechanism results in a bulky and heavy structure. Consequently, the overall exoskeleton is too big for a wearable solution. This paper proposes a digital prototype and kinematic evaluation of a cable-driven orthosis for pronation/supination movement assistance. The actuator is based on an open ring (semi-circle) to be attached to the forearm, while a stationary guide drives the ring into a rotary movement. By considering anthropomorphic data in the design stage, it is possible to develop a rigid, compact, and high power to weight ratio solution for the actuator responsible for pronation and supination. The proposed actuator can achieve the full range of motion for the activities of daily living and 83% of the rotation of the forearm total range of motion with a total mass of only 150 g.

Rod fracture after multiple-rod constructs for adult spinal deformity

2020 ◽  
Vol 32 (3) ◽  
pp. 407-414
Author(s):  
Jong-myung Jung ◽  
Seung-Jae Hyun ◽  
Ki-Jeong Kim ◽  
Tae-Ahn Jahng
Keyword(s):  
Spinal Deformity ◽  
Interbody Fusion ◽  
Adult Spinal Deformity ◽  
Multivariable Analysis ◽  
Consecutive Series ◽  
Lumbosacral Junction ◽  
Scoliosis Research Society ◽  
Radiological Parameters ◽  
Rod Fracture

OBJECTIVEThis study investigated the incidence and risk factors of rod fracture (RF) after multiple-rod constructs (MRCs) for adult spinal deformity (ASD) surgery.METHODSA single-center, single-surgeon consecutive series of adult patients who underwent posterior thoracolumbar fusion at 4 or more levels using MRCs after osteotomy with at least 1 year of follow-up were retrospectively reviewed. Patient characteristics, radiological parameters, operative data, and clinical outcomes (on the Scoliosis Research Society-22r questionnaire) were analyzed at baseline and follow-up.RESULTSSeventy-six patients were enrolled in this study. RF occurred in 9 patients (11.8%), with all cases involving partial rod breakage. Seven patients (9.2%) underwent revision surgery. There were no significant differences in baseline demographic characteristics, radiological parameters, and surgical factors between the RF and non-RF groups. Multivariable analysis revealed that interbody fusion at the L5–S1 and L4–S1 levels could significantly reduce the occurrence of RF after MRCs for ASD (adjusted odds ratios 0.070 and 0.035, respectively). The RF group had significantly worse function score (mean 2.9 ± 0.8 vs 3.5 ± 0.7) and pain score (mean 2.8 ± 1.0 vs 3.5 ± 0.8) compared with the non-RF group at last visit.CONCLUSIONSRF occurred in 11.8% of patients with MRCs after ASD surgery. Most RFs occurred at the lumbosacral junction or adjacent level (77%). Interbody fusion at the lumbosacral junction (L5–S1 or L4–S1 level) could significantly prevent the occurrence of RF after MRCs for ASD.

Time Block After Time Block

ASHA Leader ◽  
2013 ◽  
Vol 18 (8) ◽  
pp. 40-45 ◽  
Author(s):  
Judy Rudebusch ◽  
JoAnn Wiechmann
Keyword(s):  
Full Range ◽  
Time Block ◽  
School Based ◽  
Schedule Activity

To offer a full range of RTI and IEP services, school-based SLPs can schedule activity blocks rather than go student by student—here's how.

The Use of Neuroplastic Principles Affects the Swallow Motor Plan of a Patient in Severe Cognitive Decline: A Case Study

2016 ◽  
Vol 1 (15) ◽  
pp. 79-83
Author(s):  
Ed Bice ◽  
Kristine E. Galek
Keyword(s):  
Central Nervous System ◽  
Cognitive Decline ◽  
Full Range ◽  
Movement Speed ◽  
Positive Outcomes ◽  
Verbal Cues ◽  
Motor Plan ◽  
Bolus Size ◽  
The Central Nervous System

Dysphagia is common in patients with dementia. Dysphagia occurs as a result of changes in the sensory and motor function of the swallow (Easterling, 2007). It is known that the central nervous system can undergo experience-dependent plasticity, even in those individuals with dementia (Park & Bischof, 2013). The purpose of this study was to explore whether or not the use of neuroplastic principles would improve the swallow motor plan and produce positive outcomes of a patient in severe cognitive decline. The disordered swallow motor plan was manipulated by focusing on a neuroplastic principles of frequency (repetition), velocity of movement (speed of presentation), reversibility (Use it or Lose it), specificity and adaptation, intensity (bolus size), and salience (Crary & Carnaby-Mann, 2008). After five therapeutic sessions, the patient progressed from holding solids in her mouth with decreased swallow initiation to independently consuming a regular diet with full range of liquids with no oral retention and no verbal cues.

Assessment of extracranial-intracranial bypass in Moyamoya disease using 3T time-of-flight MR angiography: Comparison with CT angiography

VASA ◽  
2014 ◽  
Vol 43 (4) ◽  
pp. 278-283 ◽  
Author(s):  
Qian Chen ◽  
Rongfeng Qi ◽  
Xiaoqing Cheng ◽  
Changsheng Zhou ◽  
Song Luo ◽  
...  
Keyword(s):  
Image Quality ◽  
Moyamoya Disease ◽  
Mr Angiography ◽  
Time Of Flight ◽  
Consecutive Series ◽  
Tof Mra ◽  
Bypass Patency ◽  
Significant Difference ◽  
Contrast Technique ◽  
Vessel Integrity

Background: To evaluate the value of time-of-flight MR angiography (TOF MRA) for the assessment of extracranial-intracranial (EC-IC) bypass in Moyamoya disease in comparison with computed tomography angiography (CTA). Patients and methods: A consecutive series of 23 patients with Moyamoya disease were analyzed retrospectively. Twenty three patients underwent 25 procedures of extracranial-intracranial bypass. Cranial CTA was performed within one week after the surgery to assess bypass patency. Then TOF MRA was scanned within 24 h after CTA on a 3T MRI system. Using 5-point scales (0 = poor to 4 = excellent), two radiologists rated the image quality and vessel integrity of bypass for three segments (extracranial, trepanation, intracranial). Results: Image quality was high in both CTA and TOF MRA (mean quality score 3.84 ± 0.37 and 3.8 ± 0.41), without statistical difference (p = 0.66). Mean scores of TOF MRA with respect to bypass visualization were higher than CTA in the intracranial segment (p = 0.026). No significant difference of bypass visualization regarding the extracranial and trepanation segments was found between TOF MRA and CTA (p = 0.66 and p = 0.34, respectively). For the trepanation segment, TOF MRA showed pseudo lesions in 2 of all 25 cases. Conclusions: 3T TOF MRA, a non-contrast technique not exposing the patients to radiation, proved to be at least equal to CTA for the assessment of EC-IC bypass, and even superior to CTA with respect to the intracranial segment. In addition, readers should be aware of a potential overestimation showing focal pseudo lesions of the bypass at the trepanation segment in TOF MRA.

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