Introduction. The conventional
Objective. In a cruciate retaining total knee arthroplasty (CR-TKA) for patients with flexion contracture, to ensure that an extension gap is of sufficient size to install an implant, the amount of distal femur
BACKGROUND. We conducted this study to determine if the pre-surgical patient specific instrumented planning based on Computed tomography scans can accurately predict each of the femoral and tibial resections. The technique helps in optimization of component positioning and hence overall alignment thereby reducing errors. This makes it less invasive, more efficient and cost effective. The surgical plan in combination with the cutting guides determine the resection thickness, component size, femoral rotation and femoral and tibial component alignment. Several clinical studies have shown that PSI is safe, accurate and reproducible in primary TKA. Accurate preparation of the femoral and tibial surfaces will determine alignment and component positioning and this in turn reflects on function and longevity. METHODS. The study was conducted prospectively between May 2016 and December 2017 in our institution. Patients admitted over a period of these twenty months were included in the study. Patients with primary or secondary osteoarthritis (OA) and inflammatory arthritis who were suitable to undergo patient-specific TKA were included in the study. Patients with conventional instrumented TKR and those with significant deformities requiring constrain including valgus or varus of greater than 20 degrees with incompetent lateral or medial collateral ligaments were excluded from the study along with revisions of partial knee to TKA using PSI blocks. Prophecy® Preoperative Navigation 3D printed Guides were used for the Evolution Medial Pivot knee replacement system (. Microport Orthopaedics (Arlington, TN 38002, USA)). in all cases. The operating surgeon measured all the resections made (4 femoral and 2 tibial) using vernier calipers intraoperatively. These measurements were then compared with the preoperative CT predicted
Introduction. Although, the total knee arthroplasty (TKA) procedure is performed to make the same extension gap (EG) and flexion gap (FG) of the knee, it is not clear how the gaps can be created equally. According to earlier reports, the gaps after
Distal femur resection for correction of flexion contractures in total knee arthroplasty (TKA) can lead to joint line elevation, abnormal knee kinematics and patellofemoral problems. The aim of this retrospective study was to establish the contribution of soft tissue releases and bony cuts in the change in maximum knee extension in TKA. Data were available for 209 navigated TKAs performed by a single surgeon using a medial approach. All patients had the same cemented implant, either CR or PS, which both required a minimum thickness of 10 mm for the tibial and 9mm for the femoral component. Intra-operatively pre- and post-implant extension angles and the size of
In this study, we aim to compare total bone amount extracted in total knee arthroplasty in implant design and the bone amount extracted through intercondylar femoral notch cut. In this study, we implemented 10 implants on a total of 50 sawbones from 5 different total knee arthroplasty implant brands namely Nex-Gen Legacy (Zimmer, Warsaw, IN, USA), Genesis 2 PS (Smith&Nephew, Memphis, TN, USA), Vanguard (Biomet Orthopedics Inc., Warsaw, IN, USA), Sigma PS (De Puy, Johnson&Johnson, Warsaw, IN, USA), Scorpio NRG PS (Stryker Co., Kalamazoo, USA). Equal or the closest sizes of each brand on anteroposterior plane were selected, and cuts were made following standard technique(see Fig 1 and 2). Extracted bone pieces were measured in terms of volume and length on three planes, and statistically analysed. The volume of all pieces available after each femoral incision was measured according to Archimedes’ principles. Furthermore, the volume of each intercondylar femoral notch pieces was measured separately from other pieces but with the same method. The measurement of intercondylar femoral notch pieces on 3 planes (medial-lateral, anterior-posterior, superior-inferior) was made using Kanon slide gauge (Ermak Ltd, Istanbul, TR). Femoral notch incision pieces were scanned with CAD/CAM technology using three-dimensional scanner 1 SeriesTM (Dental Wings Inc, Montreal, QC, Canada), and the measurements were confirmed with DWOS CAD 4.0.1 software (Dental Wings Inc, Montreal, QC, Canada)(see figure 3a-e). The volume of 10 intercondylar femoral notch pieces performed through the set of each brand was averaged, and considered as the incision volume of that particular brand.Objective
Material and Method
Introduction. Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal
INTRODUCTION. Mechanical alignment in TKA introduces significant anatomic modifications for many individuals, which may result in unequal medial-lateral or flexion-extension
Abstract. Background. Conventional TKR aims for neutral mechanical alignment which may result in a smaller lateral distal femoral condyle resection than the implant thickness. We aim to explore the mismatch between implant thickness and
Introduction. Studies have shown that dissatisfaction following TKA may stem from poor component placement and iatrogenic factors related to variability in surgical execution. A CT-based robotic assisted system (RA) allows surgeons to dynamically balance the joint prior to
Introduction. Soft tissue releases are often required to correct deformity and achieve gap balance in total knee arthroplasty (TKA). However, the process of releasing soft tissues can be subjective and highly variable and is often perceived as an ‘art’ in TKA surgery. Releasing soft tissues also increases the risk of iatrogenic injury and may be detrimental to the mechanically sensitive afferent nerve fibers which participate in the regulation of knee joint stability. Measured resection TKA approaches typically rely on making bone cuts based off of generic alignment strategies and then releasing soft tissue afterwards to balance gaps. Conversely, gap-balancing techniques allow for pre-emptive adjustment of
Aim. Adequate debridement of necrotic bone is of paramount importance for eradication of infection in chronic osteomyelitis. Currently, no tools are available to detect the exact amount of necrotic bone in order to optimize surgical resection. The aim of the present study was to evaluate the feasibility of an intraoperative illumination method (VELscope. ®. ) and the correlation between intraoperative and pathohistological findings in surgically treated chronic fracture related infection patients. Method. Ten consecutive patients with chronic fracture related infections of the lower extremity were included into this prospectively performed case series. All patients had to be treated surgically for fracture related infections requiring bony debridement. An intraoperative illumination method (VELscope®) was used to intraoperatively differentiate between viable and necrotic bone. Tissue samples from the identified viable and necrotic bone areas were histopathologically examined and compared to intraoperative findings. Results. In all included patients, the intraoperative illumination was deemed helpful to differentiate between necrotic and viable bone tissues during bony debridement. The histopathological examination of the samples showed good correlation of the intraoperative illumination findings with histopathological signs of necrosis for areas deemed dead and histopathological signs of intact bone for areas deemed vital during illumination. Conclusions. The fluorescence-assisted, intraoperative detection of necrotic and viable bone using the VELscope. ®. is an easy-to-use procedure that can help surgeons to optimize intraoperative
Computer Assisted Surgery (CAS) and Patient Specific Instrumentation (PSI) have been reported to increase accuracy and predictability of tumour resections. The technically demanding joint-preserving surgery that retains the native joint with the better function may benefit from the new techniques. This cadaver study is to investigate the surgical accuracy of CAS and PSI in joint-preserving surgery of knee joint. CT scans of four cadavers were performed and imported into an engineering software (MIMICS, Materialise) for the 3D surgical planning of simulated, multiplanar joint-preserving resections for distal femur or proximal tibia metaphyseal bone sarcoma. The planned resections were transferred to the navigation system (OrthoMap 3D, Stryker) for navigation planning and used for the design and fabrication of the PSI. Each of the four techniques (freehand, CAS, PSI and CAS + PSI) was used in four joint-preserving resections. Location accuracy (the maximum deviation of distance between the planned and the achieved resections) and
Background. Conventional instrumented total knee arthroplasty uses fixed angles for bony cuts followed by soft tissue releases to achieve balance. Robotic-assisted surgery allows for soft tissue balancing first then bony resection. The changes to the implant position from conventional instrumented surgery were measured and recorded. Methods. A single center, retrospective study reviewed consecutive total knee replacement surgeries over a 12 month period utilizing robotic pre-planning and balancing techniques. Changes to femoral and tibial varus/valgus and femoral rotation from traditional instrumented surgery positions were analyzed. Results. There were 145 knees which were grouped by preoperative deformity and the changes were frequent (94%), variable for any given deformity, and often unpredictable. Staged bilateral total knee arthroplasty patients also showed variability between knees. Conclusion. Robotic-assisted knee replacement technology not only has the advantage of navigation with regard to accurate implant positioning but also provides real-time, actionable data to better position the implant prior to
Background. Intraoperative balancing of total knee arthroplasty (TKA) can be accomplished by either more prevalent but less predictable soft tissue releases, implant realignment through adjustments of
The iASSIST system is a portable, accelerometer base with electronic navigation used for total knee arthroplasty (TKA) which guides the surgeon to align and validate
Introduction. Patient specific instrumentation (PSI) generates customized guides from an MRI- or CT-based preoperative plan for use in total knee arthroplasty (TKA). PSI software executes the preoperative planning process. Several manufacturers have developed proprietary PSI software for preoperative planning. It is possible that each proprietary software has a unique preoperative planning process, which may lead to variation in preoperative plans among manufactures and thus variation in the overall PSI technology. The purpose of this study was to determine whether different PSI software generate similar preoperative plans when applied to a single implant system and given identical MR images. Methods. In this prospective comparative study, we evaluated PSI preoperative plans generated by Materialise software and Zimmer Patient Specific Instruments software for 37 consecutive knees. All plans utilized the Zimmer Persona™ CR implant system and were approved by a single experienced surgeon blinded to the other software-generated preoperative plan. For each knee, the MRI reconstructions for both software programs were evaluated to qualitatively determine differences in bony landmark identification. The software-generated preoperative plans were assessed to determine differences in preoperative alignment, component sizes, and resection depth. PSI planned
Introduction. Robot systems have been successfully introduced to improve the accuracy and reduce severe iatrogenic soft tissue damage in knee arthroplasty. Unfortunately to perform complete a complete bone cut, the cutting tool has to slightly pass the edge of the bone. In the posterior zones were retractor protection is impossible this will lead to contact between the cutting tool and the soft tissue envelope. Therefore, complete soft tissue preservation cannot be guaranteed with the current commercial systems. Methods. This study presents an alternative robotic controlled cutting technique to perform the
Navigation-assisted surgery has been reported to enhance resection accuracy in bone sarcoma surgery. Patient-specific instruments (PSIs) have been proposed as a simpler alternative with fewer setup facilities. We investigated the use of 3D surgical planning and PSI in realising computer planning of complex
Introduction. Clinical outcomes for total knee arthroplasty (TKA) are especially sensitive to lower extremity alignment and implant positioning. 1. The use of computer-assisted orthopaedic surgery (CAOS) can improve overall TKA accuracy. 2. This study assessed the accuracy of an image-free CAOS guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) in both a synthetic leg with a normal mechanical axis and legs with abnormal mechanical axis. Materials and methods. A high-resolution 3D scanner (Comet L3D, Steinbichler, Plymouth, MI) was used to scan varus-deformed (n=12), neutral (n=12), and valgus-deformed (n=4) knee inserts (Mita M-00566, M-00598, M-00567; respectively, Medical Models, Bristol, UK) and collect pre-identified anatomical landmarks prior to using the models to simulate knee surgery. The image-free CAOS guidance system was then used to acquire the same landmarks. After adjusting the position and orientation of the cutting block to match the targets,