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Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_4 | Pages 11 - 11
1 Apr 2019
Wong M Desai B Bautista M Kwon O Chimento G
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PURPOSE

YouTube is a video sharing platform that is a common resource for patients seeking medical information. The objective of this study is to assess the educational quality of YouTube videos pertaining to total knee arthroplasty and knee arthritis.

METHODS

A systematic search for the terms “knee replacement” and “knee arthritis” was performed using Youtube's search function. Data from the 60 most relevant videos were collected for each search term. Videos not in English or those without audio or captions were excluded. Quality assessment checklists with a scale of 0 to 10 points were developed to evaluate the video content. Videos were grouped into poor quality (grade 0–3), acceptable quality (grade 4–7) and excellent quality (grade 8– 10), respectively. Four independent reviewers assessed the videos using the same grading system and independently scored all videos. Discrepancies regarding the scoring were clarified by consensus discussion.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 27 - 27
1 May 2016
Kwon O Baek C Kang K Son J Koh Y
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Unicompartmental knee arthroplasty (UKA) is often considered to be attractive alternate surgical technique to total knee arthroplasty (TKA) and high tibial osteotomy (HTO), in particular young patients. In addition, it is recently reported that preservation of joint line in UKA is crucial factor for positive long-term outcome, especially in revision case for UKA. However, the role of this joint line has neither been invested nor is it consciously bothered during surgical implantation.

Validated finite element (FE) analysis was introduced in this study to investigate the effects of maximum contact stress on polyethylene (PE) insert and maximum compressive stress in opposite compartments for joint line in fixed-type UKA. As suggested by Weber et al., FE model for joint line was developed by means of determination of the angle between the pre-operative joint line and the reference line from lateral cortical is of the femur. Based on the method above, joint lines were modeled in −3, −2, −1, 0, +1, +2, and +3 mm cases and these seven FE models were compared and analyzed (Fig. 1). All implant components were modeled as linear elastic isotropic materials. However, the model was considered to have plastic characteristics of PE insert. FE analysis was performed using high kinematics displacement and rotation inputs, which were based on the kinematics of the natural knee. ISO standards were used for axial load and flexion (Fig. 2).

The FE model was subjected to validation based on cadaveric experimental data available in the literature by Sohn et al. and from previous cadaveric tests conducted by current investigators. The maximum contact stress was found at around 43 % of the gait cycle in 0 mm case. There were no difference between ± 1 and 0 mm cases, but maximum contact stress on PE insert becomes greater in ± 3 mm cases. The maximum compressive stress of the lateral meniscus in 0 mm case occurred at 62 % of the gait cycle. There were no difference in positive joint line cases in maximum compressive stress, however maximum compressive stress of the lateral meniscus becomes greater in - 3 mm cases.

This study emphasized the importance of joint line preservation after implantation of UKA. It would be critical to determine the joint line in UKA surgery in future based on the result showing that there has been no remarkable difference in stress but changed rapidly from the position beyond the joint line. In future study, it would be valuable study to compare between joint lines of fixed- and mobile-type UKA.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_10 | Pages 143 - 143
1 May 2016
Yoon S Lee C Hur J Kwon O Lee H
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Introduction

Mechanically aligned total knee arthroplasty(TKA) relies on restoring the hip-knee-ankle angle of the limb to neutral or as close to a straight line as possible. This principle is based on studies that suggest limb and knee alignment is related long term survival and wear. For that cause, there has been recent attention concerning computer-assisted TKA and robot is also one of the most helpful instruments for restoring neutral alignment as known. But many reported data have shown that 20% to 25% of patients with mechanically aligned TKA are dissatisfied. Accordingly, kinematically aligned TKA was implemented as an alternative alignment strategy with the goal of reducing prevalence of unexplained pain, stiffness, and instability and improving the rate of recovery, kinematics, and contact forces. So, we want to report our extremely early experience of robot-assisted TKA planned by kinematic method.

Materials and Methods

This study evaluated the very short term results (6 weeks follow up) after robot-assisted TKA aligned kinematically. 50 knees in 36 patients, who could be followed up more than 6 weeks after surgery from December 2014 to January 2015, were evaluated prospectively. The diagnosis was primary osteoarthritis in all cases. The operation was performed with ROBODOC (ISS Inc., CA, USA) along with the ORTHODOC (ISS Inc., CA, USA) planning computer. The cutting plan was made by single radius femoral component concept, each femoral condyles shape-matched method along the transverse axis using multi-channel CT and MRI to place the implant along the patient's premorbid joint line. Radiographic measurements were made from long bone scanograms. Clinical outcomes and motion were measured preoperatively and 6 weeks postoperatively.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 367 - 367
1 Mar 2013
Yoon S Lee C Hur J Kwon O Trabish M Lee H Park J
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Introduction

The success of total knee arthroplasty depends on many factors, including the preoperative condition of the patient, the design and materials of the components and surgical techniques. It is important to position the femoral and tibial components accurately and to balance the soft tissues. Malpositioning of the component can lead to failures due to aseptic loosening, instability, polyethylene wear and dislocation of the patella. In order to improve post-operative alignment, computer-aid systems have been developed for total knee arthroplasty. Many clinical and experimental studies of these systems have shown that the accuracy of implanted components can be improved in spite of the increase in costs and operating time. This may not, however, improve the outcome in the short-term. Restoration of the normal mechanical axis of the knee and balancing of the surrounding soft tissues have been shown to have an important bearing on the final outcome of knee replacement operations. In severely deformed knees, whether varus or valgus, these goals may be difficult to achieve. We compared the radiologic results of the mechanical axis and implant position of Total Knee Arthroplasty using a robot-assisted method with conventional manually implanted method in severe varus deformed knee.

Materials and Methods

A data set of 50 consecutive cases that were performed from April 2007 to December 2010 using the robot assisted TKA(Group A) were compared with a data set of 50 consecutive cases from the same period that were done using conventional manual TKA(Group B). All cases had a preoperative mechanical varus deformity >15° and one brand of implant was used on all cases. The diagnosis was primary osteoarthritis in all knees. The operations were performed by one-senior author with the same robot system, ROBODOC (ISS Inc., CA, USA) along with the ORTHODOC (ISS Inc., CA, USA) planning computer. (See Figure 1.) The radiological evaluations included mechanical axis, implant position (α,β,γ,δ angle) according to the system of American Knee Society.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 366 - 366
1 Mar 2013
Yoon S Lee C Hur J Kwon O Trabish M Lee H Park J
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Introduction

Since Smith-Peterson's glass mold arthroplasty in 1939, hip resurfacing arthroplasty was developed and introduced to orthopaedic surgery field but it had many problem like early loosening. Recently it is being popular for some indication as development of new implant design and manufacturing. There are still many suggested advantages of hip resurfacing arthroplasty. These include bone conservation, improved function as a consequence of retention of the femoral head and neck and more precise biomechanical restoration, decreased morbidity at the time of revision arthroplasty, reduced dislocation rates, normal femoral loading and reduced stress-shielding, simpler management of a degenerated hip with a deformity in the proximal femoral metaphysic, an improved outcome in the event of infection, and a reduced prevalence of thromboembolic phenomena as a consequence of not using instruments in the femur. But, there are limited or inconsistent data to support some of these claims regarding the benefits of hip resurfacing including the potential for a more natural feel because of the minimal disturbance of the proximal part of the femur resulting in a better and faster functional outcome. We evaluate the short term results of hip resurfacing arthroplasty using custom patient-specific tooling for prosthesis placement for better standardization.

Materials and Methods

40 cases, 36 patients(male:20, female:16) those of who were candidates of a Hip Resurfacing procedure, participated in the study. Mean follow up period was 2.5 years (8 months ∼3 years). A CT scan was performed on each patient and a 3D model was generated using the computer tomography dataset. From this model a bone-surface skin was extracted and this data set was used to create a personalized jig. Detailed analysis of the native bone structure was then used to preoperatively plan the appropriate size and position of the implant. A mean 7 degree corrective valgus angle was prescribed on all cases. Postoperative radiological datasets were superimposed onto preoperative plan position and offsets were measured. Operative times were recorded per step during the procedure. Surgeon comfort and ease of use was also noted.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXV | Pages 124 - 124
1 Jun 2012
Kwon O Kamath A Voleti P Garino J
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Introduction

While the use of stemmed implants is accepted for patients with medial ligament laxity in primary total knee arthroplasty (TKA), the role of stemmed implants in the setting of isolated lateral laxity is unclear. We present a cohort study to assess the effect of unstemmed, constrained TKA for isolated lateral laxity.

Methods

1745 primary TKA performed by the senior surgeon were reviewed. 39 knees in 33 patients with isolated lateral laxity managed with unstemmed components were compared to matched stemmed controls (37 knees in 28 patients). Lateral instability was defined intra-operatively based on >7mm gap in mid-flexion/full extension/figure-of-four with well-positioned components. Primary outcome measures were clinical failure for aseptic loosening (with need for revision as the endpoint) and any radiographic signs of loosening.