scholarly journals Optimizing TKA Positioning via Intraoperative Ligament Characterization

10.29007/6kb5 ◽  
2020 ◽  
Author(s):  
Alexander Orsi ◽  
Edgar Wakelin ◽  
Sami Shalhoub ◽  
Jeffrey Lawrence ◽  
Corey Ponder ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Transition Point ◽  
Load Cycle ◽  
Patient Specific ◽  
Specific Method ◽  
Joint Force ◽  
Soft Tissue Envelope ◽  
Tibial Resection ◽  
Ligament Tension ◽  
Balancing Robot

The goal of total knee arthroplasty (TKA) is to position the prosthesis with a bal- anced soft tissue envelope throughout the flexion cycle. Determining a desirable amount of ligament tension is crucial as instability is a leading cause for revision surgery. This is challenging due to the subject specific, and non-linear, nature of ligament mechanical properties. This study aims to characterize ligament stiffness profiles intraoperatively and identify the stiffness transition point (STP) using a ligament balancing robot. The study will also identify how the surgeon selected joint force relates to the stiffness transition point.45 patients were reviewed. After the proximal tibial resection, intraoperative assessment of the medial and lateral ligaments was performed via a load cycle ramped up from 50N to 120N, then down from 120N to 50N. This was performed at extension (10◦) and in flexion (90◦). Force and displacement data were processed to determine the stiffness profiles for the medial and lateral soft tissue envelope. A bilinear fit model was used to determine the slopes and STP.The average STP was between 83N and 90N, varying widely with standard deviations approaching 14N. The median joint tension selected by the surgeon was 80N. On average the selected joint force was 3N to 8.9N below the STP.The medial compartment behaved similarly in extension and flexion. The lateral com- partment had higher stiffness in extension than in flexion. Across all loading conditions, the down-cycle data was more consistent than the up-cycle data.The STP is a proposed target for ligament tension as this theoretically avoids the high stiffness regime. The results show the joint tension selected by the surgeons, based on their experience and intraoperative feel, is similar to the STP. Due to the high patient variability observed in the STP, using a patient specific method to determine the joint tension is recommended. Future work will investigate how joint tension relative to the STP affects patient outcomes. This will provide insight into optimizing joint tension during TKA.

scholarly journals The effect of arthroscopic capsulotomy and repair on native resting hip joint forces using a non-destructive extra-articular method

2019 ◽  
Author(s):  
Joseph C Schaffer ◽  
Daniel Vasconcellos ◽  
Meghan Kelly ◽  
Nathan B Kaplan ◽  
Noorullah Maqsoodi ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Hip Joint ◽  
Native State ◽  
Joint Force ◽  
Soft Tissue Envelope ◽  
Capsular Repair ◽  
Soft Tissue Dissection ◽  
Tissue Dissection ◽  
Fresh Frozen ◽  
Hip Approach

Abstract Previous methods for measuring intra-articular forces require significant soft tissue dissection and intra-articular insertion of sensory instruments. This study demonstrates a minimally invasive method of measuring native resting hip joint force without disrupting the soft tissue envelope. This method is then utilized to determine the effect of capsulotomy and repair on these forces. Twenty fresh-frozen human cadaver hemipelves were percutaneously instrumented with an iliac crest locking plate and retrograde femoral nail to allow for testing using a distracting force. Force–displacement curves were generated in the native state, and after joint venting, an anterior hip approach, capsulotomy, capsular repair and soft tissue dissections. Mean native resting hip joint force was 110.5 N (SD 54.3 N). Capsular venting resulted in a significant decrease in hip joint force compared with the native state (100.2 N, SD 45.2 N, P = 0.026). A further decrease in hip joint force was observed with a T-capsulotomy (79.9 N, SD 40.1 N, P < 0.001 compared with anterior hip approach), with restoration of these forces after capsular repair (84.8 N, SD 40.5, P = 0.014 versus T-capsulotomy and P = 0.67 versus anterior hip approach). Soft tissue dissection resulted in a large decrease in hip joint force compared with the hip’s native state (59.7 N, SD 28.4 N, P = 0.002). Taken together, the findings suggest that this method is effective in measuring hip joint force and may be more accurate than those requiring significant soft tissue dissection. Furthermore, the data suggest that capsular repair likely plays an important role in the restoration of biomechanical forces in the hip after capsulotomy.

scholarly journals Can a well balanced soft tissue envelope speed up the postoperative treatment and improve clinical follow-up? A control - pilot study using a dynamic ligament balancing device based on functional stability

10.29007/n8xw ◽  
2020 ◽  
Author(s):  
Thomas Paszicsnyek ◽  
Edoardo Bori ◽  
Christoph Stiegler ◽  
Bernardo Innocenti
Keyword(s):  
Pilot Study ◽  
Soft Tissue ◽  
Electronic Device ◽  
Postoperative Treatment ◽  
Control Group ◽  
Functional Stability ◽  
Joint Stability ◽  
Ligament Balancing ◽  
Soft Tissue Envelope ◽  
Ligament Tension

IntroductionWorldwide, the number of TKA implants is increasing. Even if registry demonstrate that TKA as high satisfaction rate, there are still between 15 and 20% dissatisfied patients.Materials and methodsThe proper soft tissue balancing is one of the most discussed topics of the last years. We initiated a study using an electronic device („dynamic ligament balancing sensorplate“) to compare the benefit of the measurement of ligament tension, space and position in comparison to a conventional surgical procedure. Beside that, we followed the concept of functional stability, which tells us, that a tension of 40N in total is sufficient to reach proper (functional) joint stability.This control pilot study was set up as a single surgeon, single center study and consists of 25 patients treated by the use of the sensorplate and a control group of 25 patients, treated in a conventional setup.We used the following scores for evaluation: OKS, AKSS and FJS, preoperatively and during the FU examinations (postoperative, 6 weeks, 3 months, 6 months and 1 year)Beside scoring, clinical examination and routine x-ray we performed an EMG testing at all FU dates.ResultsThe study was performed between January 2017 and May 2019. The mean age of the patients was in average 72 years, 66 % female and 34 % male. After 1 year, results demonstrate a clear difference in the development of the postoperative situation between dynamic balanced TKA and the control one.So, the use of such electronic device improving the soft tissue envelope stability, enable a significantly better patient FU, especially in terms of OKSDiscussionThe DLB system is a new option to value and improve the soft tissue envelope tensioning during the surgical TKA operation. It allows to measure ligament tension, slope and joint space all over the entire ROM.ConclusionUsing an electronic device for measurement is an advanced option to improve patient satisfaction after tka. Like the studies of other existing devices have shown before there is a massive change in the kinematic behaviour of the muscular abilities by using these tools for a better soft tissue balance. The DLB system is another option by showing 3 different measurement results (tension, distance and joint angle) to adapt the implantation procedure to the individual situation of the patient.

scholarly journals True Kinematic Alignment Is Applicable in 44% of Patients Applying Restrictive Indication Criteria—A Retrospective Analysis of 111 TKA Using Robotic Assistance

2021 ◽  
Vol 11 (7) ◽  
pp. 662
Author(s):  
Kim Huber ◽  
Bernhard Christen ◽  
Sarah Calliess ◽  
Tilman Calliess
Keyword(s):  
Soft Tissue ◽  
Retrospective Analysis ◽  
Patient Specific ◽  
Kinematic Alignment ◽  
Postoperative Phase ◽  
Robotic Assistance ◽  
Component Position ◽  
Joint Stability ◽  
Robotic Assisted ◽  
Primary Tkas

Introduction: Image-based robotic assistance appears to be a promising tool for individualizing alignment in total knee arthroplasty (TKA). The patient-specific model of the knee enables a preoperative 3D planning of component position. Adjustments to the individual soft-tissue situation can be done intraoperatively. Based on this, we have established a standardized workflow to implement the idea of kinematic alignment (KA) for robotic-assisted TKA. In addition, we have defined limits for its use. If these limits are reached, we switch to a restricted KA (rKA). The aim of the study was to evaluate (1) in what percentage of patients a true KA or an rKA is applicable, (2) whether there were differences regarding knee phenotypes, and (3) what the differences of philosophies in terms of component position, joint stability, and early patient outcome were. Methods: The study included a retrospective analysis of 111 robotic-assisted primary TKAs. Based on preoperative long leg standing radiographs, the patients were categorized into a varus, valgus, or neutral subgroup. Initially, all patients were planned for KA TKA. When the defined safe zone had been exceeded, adjustments to an rKA were made. Intraoperatively, the alignment of the components and joint gaps were recorded by robotic software. Results and conclusion: With our indication for TKA and the defined boundaries, “only” 44% of the patients were suitable for a true KA with no adjustments or soft tissue releases. In the varus group, it was about 70%, whereas it was 0% in the valgus group and 25% in the neutral alignment group. Thus, significant differences with regard to knee morphotypes were evident. In the KA group, a more physiological knee balance reconstructing the trapezoidal flexion gap (+2 mm on average laterally) was seen as well as a closer reconstruction of the surface anatomy and joint line in all dimensions compared to rKA. This resulted in a higher improvement in the collected outcome scores in favor of KA in the very early postoperative phase.

scholarly journals Evaluating a calcium-aware kernel for CT CAC scoring with varying surrounding materials and heart rates: a dynamic phantom study

2021 ◽  
Author(s):  
Niels R. van der Werf ◽  
Ronald Booij ◽  
Bernhard Schmidt ◽  
Thomas G. Flohr ◽  
Tim Leiner ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Soft Tissue ◽  
Patient Specific ◽  
Reconstruction Technique ◽  
Ct Reconstruction ◽  
Raw Data ◽  
Heart Rates ◽  
Tissue Equivalent ◽  
Tin Filtration ◽  
Reconstruction Kernel

Abstract Objectives The purpose of this study was twofold. First, the influence of a novel calcium-aware (Ca-aware) computed tomography (CT) reconstruction technique on coronary artery calcium (CAC) scores surrounded by a variety of tissues was assessed. Second, the performance of the Ca-aware reconstruction technique on moving CAC was evaluated with a dynamic phantom. Methods An artificial coronary artery, containing two CAC of equal size and different densities (196 ± 3, 380 ± 2 mg hydroxyapatite cm−3), was moved in the center compartment of an anthropomorphic thorax phantom at different heart rates. The center compartment was filled with mixtures, which resembled fat, water, and soft tissue equivalent CT numbers. Raw data was acquired with a routine clinical CAC protocol, at 120 peak kilovolt (kVp). Subsequently, reduced tube voltage (100 kVp) and tin-filtration (150Sn kVp) acquisitions were performed. Raw data was reconstructed with a standard and a novel Ca-aware reconstruction technique. Agatston scores of all reconstructions were compared with the reference (120 kVp) and standard reconstruction technique, with relevant deviations defined as > 10%. Results For all heart rates, Agatston scores for CAC submerged in fat were comparable to the reference, for the reduced-kVp acquisition with Ca-aware reconstruction kernel. For water and soft tissue, medium-density Agatston scores were again comparable to the reference for all heart rates. Low-density Agatston scores showed relevant deviations, up to 15% and 23% for water and soft tissue, respectively. Conclusion CT CAC scoring with varying surrounding materials and heart rates is feasible at patient-specific tube voltages with the novel Ca-aware reconstruction technique. Key Points • A dedicated calcium-aware reconstruction kernel results in similar Agatston scores for CAC surrounded by fatty materials regardless of CAC density and heart rate. • Application of a dedicated calcium-aware reconstruction kernel allows for radiation dose reduction. • Mass scores determined with CT underestimated physical mass.

scholarly journals Redefining Knee Balance in a Medially Stabilized Prosthesis: An In-Vitro Study

2017 ◽  
Vol 11 (1) ◽  
pp. 1165-1172
Author(s):  
Philippe Van Overschelde ◽  
Vera Pinskerova ◽  
Peter P. Koch ◽  
Christophe Fornasieri ◽  
Sandro Fucentese
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
In Vitro Study ◽  
Lateral Release ◽  
Soft Tissue Release ◽  
Iliotibial Band ◽  
Soft Tissue Envelope ◽  
Medial Side ◽  
Fresh Frozen

Background: To date, there is still no consensus on what soft tissues must be preserved and what structures can be safely released during total knee arthroplasty (TKA) with a medially stabilized implant. Objective: The aim of this study was to analyze the effect of a progressive selective release of the medial and lateral soft tissues in a knee implanted with a medially stabilized prosthesis. Method: Six cadaveric fresh-frozen full leg specimens were tested. In each case, kinematic pattern and mediolateral laxity were measured in three stages: firstly, prior to implantation; secondly, after the implantation of the trial components, but before any soft tissue release; and thirdly, progressively as soft tissue was released with the trial implant in place. The incremental impact of each selective release on knee balance was then analyzed. Results: In all cases sagittal stability was not affected by the progressive release of the lateral soft tissue envelope. It was possible to perform progressive lateral release provided the anterior one-third of the iliotibial band (ITB) remained intact. Progressive medial release could be performed on the medial side provided the anterior fibers of the superficial medial collateral ligament (sMCL) remained intact. Conclusion: The medially conforming implant remains stable provided the anterior fibers of sMCL and the anterior fibers of the ITB remain intact. The implant’s sagittal stability is mainly dependent on its medial ball-in-socket design.

scholarly journals What is a balanced knee replacement?

2018 ◽  
Vol 3 (12) ◽  
pp. 614-619 ◽  
Author(s):  
Lucy C. Walker ◽  
Nick D. Clement ◽  
Kanishka M. Ghosh ◽  
David J. Deehan
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Replacement ◽  
Knee Arthroplasty ◽  
Current Evidence ◽  
Soft Tissue Envelope ◽  
Total Knee ◽  
Uneven Wear ◽  
Definition Of ◽  
Revision Tka

For multifactorial reasons an estimated 20% of patients remain unsatisfied after total knee arthroplasty (TKA). Appropriate tension of the soft tissue envelope encompassing the knee is important in total knee arthroplasty and soft tissue imbalance contributes to several of the foremost reasons for revision TKA, including instability, stiffness and aseptic loosening. There is debate in the literature surrounding the optimum way to achieve balancing of a total knee arthroplasty and there is also a lack of an accepted definition of what a balanced knee replacement is. It may be intuitive to use the native knee as a model for balancing; however, there are many difficulties with translating this into a successful prosthesis. One of the foundations of TKA, as described by Insall, was that although the native knee has more weight transmitted through the medial compartment this was to be avoided in a TKA as it would lead to uneven wear and early failure. There is a focus on achieving symmetrical tension and pressure and subsequent ‘balance’ in TKA, but the evidence from cadaveric studies is that the native knee is not symmetrically balanced. As we are currently trying to design an implant that is not based on its anatomical counterpart, is it possible to create a truly balanced prosthesis or to even to define what that balance is? The authors have reviewed the current evidence surrounding TKA balancing and its relationship with the native knee. Cite this article: EFORT Open Rev 2018;3:614-619. DOI: 10.1302/2058-5241.3.180008.

scholarly journals Internal and External Radiofrequency Assisted Lipo-Coagulation (RFAL) in the Control of Soft Tissue Contraction during Liposuction: Part 2 “Outside In” RFAL Thermal Tissue Tightening

2021 ◽  
Author(s):  
Robert Stephen Mulholland
Keyword(s):  
Soft Tissue ◽  
Invasive Procedure ◽  
Thermal Stimulation ◽  
Thermal Coagulation ◽  
Soft Tissue Envelope ◽  
Non Invasive ◽  
Tissue Contraction ◽  
Contraction Effect ◽  
Positively Charged ◽  
Coated Electrodes

The new Morpheus8 is a novel external RFAL device that uses the proven soft tissue contraction of BodyTite in an external, non-invasive procedure. This external RF applicator, which is also powered by BodyTite, inserts up to 40 positively charged, coated electrodes 8 mm into the subcutaneous, soft tissue envelope. A monopolar ablative lesion is generated from the tip of the electrode, stimulating contraction of the FSN and adipose coagulation. The RF then flows up to the distant negative, return electrodes on the surface of the skin, providing a non-ablative thermal stimulation to the papillary dermis. The “burst” feature of the Morpheus8, delivers simultaneous multiple levels of internal coagulation in a single one second pulse, amplifying the adipose ablation and contraction effect. Studies, show, that the combination of BodyTite internal thermal coagulation and external Morpheus8 at the time of liposuction can result in 60–70% area skin contraction, greatly improving the soft tissue contours and Body shaping outcomes following lipo-contouring procedures.

Utilization of Alexandrite Laser for Hair Removal in Pediatric Auricular Reconstruction

2021 ◽  
pp. 019459982110419
Author(s):  
Peng You ◽  
Tara L. Rosenberg ◽  
Yi-Chun Carol Liu
Keyword(s):  
Soft Tissue ◽  
Chart Review ◽  
Laser System ◽  
Retrospective Chart Review ◽  
Hair Removal ◽  
Procedural Sedation ◽  
Alexandrite Laser ◽  
Auricular Reconstruction ◽  
Laser Hair Removal ◽  
Soft Tissue Envelope

Auricular reconstruction with autologous rib cartilage involves using a soft tissue envelope to cover the cartilage framework. In patients with a low hairline, hair-bearing skin may be incorporated on the reconstructed ear, creating a difficult and conspicuous aesthetic problem. A retrospective chart review was conducted to summarize and share the experience of using the Candela GentleMax Pro 755-nm alexandrite laser system (Candela Corp) in children following auricular reconstruction. Nine patients received laser hair removal via the alexandrite laser system with good results. The number of completed sessions ranged from 1 to 5. The procedures were completed without the need for premedication or procedural sedation. Laser hair removal with an alexandrite laser system was safe, fast, and effective. With multistage auricular reconstruction, it was feasible to incorporate laser hair removal between the stages.

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