scholarly journals Patient-specific medial unicompartmental knee arthroplasty has a greater protective effect on articular cartilage in the lateral compartment

2018 ◽  
Vol 7 (1) ◽  
pp. 20-27 ◽  
Author(s):  
K-T. Kang ◽  
J. Son ◽  
D-S. Suh ◽  
S. K. Kwon ◽  
O-R. Kwon ◽  
...  
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Lateral Compartment ◽  
Contact Stresses ◽  
Patient Specific ◽  
Unicompartmental Knee ◽  
Medial Unicompartmental Knee Arthroplasty ◽  
Biomechanical Effect

Objectives Patient-specific (PS) implantation surgical technology has been introduced in recent years and a gradual increase in the associated number of surgical cases has been observed. PS technology uses a patient’s own geometry in designing a medical device to provide minimal bone resection with improvement in the prosthetic bone coverage. However, whether PS unicompartmental knee arthroplasty (UKA) provides a better biomechanical effect than standard off-the-shelf prostheses for UKA has not yet been determined, and still remains controversial in both biomechanical and clinical fields. Therefore, the aim of this study was to compare the biomechanical effect between PS and standard off-the-shelf prostheses for UKA. Methods The contact stresses on the polyethylene (PE) insert, articular cartilage and lateral meniscus were evaluated in PS and standard off-the-shelf prostheses for UKA using a validated finite element model. Gait cycle loading was applied to evaluate the biomechanical effect in the PS and standard UKAs. Results The contact stresses on the PE insert were similar for both the PS and standard UKAs. Compared with the standard UKA, the PS UKA did not show any biomechanical effect on the medial PE insert. However, the contact stresses on the articular cartilage and the meniscus in the lateral compartment following the PS UKA exhibited closer values to the healthy knee joint compared with the standard UKA. Conclusion The PS UKA provided mechanics closer to those of the normal knee joint. The decreased contact stress on the opposite compartment may reduce the overall risk of progressive osteoarthritis. Cite this article: K-T. Kang, J. Son, D-S. Suh, S. K. Kwon, O-R. Kwon, Y-G. Koh. Patient-specific medial unicompartmental knee arthroplasty has a greater protective effect on articular cartilage in the lateral compartment: A Finite Element Analysis. Bone Joint Res 2018;7:20–27. DOI: 10.1302/2046-3758.71.BJR-2017-0115.R2.

scholarly journals Mobile Versus Fixed Bearing Medial Unicompartmental Knee Arthroplasty: A Series of 375 Patients

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Robert Murphy ◽  
Tyler Fraser ◽  
William Mihalko
Keyword(s):  
Range Of Motion ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Mobile Bearing ◽  
Lateral Compartment ◽  
Fixed Bearing ◽  
Unicompartmental Knee ◽  
Significant Difference ◽  
Medial Unicompartmental Knee Arthroplasty ◽  
Component Loosening

Introduction: We sought to compare outcomes, complications and survival between mobile and fixed bearing medial unicompartmental knee arthroplasty (UKA) in a large multi-surgeon group.Methods: Medical records of patients who underwent a medial UKA were queried between March 2003 and August 2012. Variables investigated included final range of motion (ROM), type of complication, and overall survivorship. Results: 375 medial UKAs were analyzed (308 mobile bearing and 67 fixed bearing). Average time to follow-up was 47 months. Final ROM was comparable (mobile: 1-122°, fixed: 1-120°, p = 0.34). Complications occurred in 20/308 (6.6%) mobile bearing UKA and 5/67 (7.5%) fixed bearing UKA (p = 0.77). The most common complications in mobile bearing implants were progression of lateral compartment disease and component loosening. The complications in fixed bearing implants were arthrofibrosis and tibial plateau fracture. Overall survivorship differed, but not significantly (mobile: 94.8%, fixed: 96.9%, p = 0.44). Discussion: In this largest reported cohort series comparing mobile versus fixed bearing UKA, we found no significant difference in final clinical knee range of motion, rates of complications, and survivorship between the two bearing types. 

Role of alignment in successful clinical outcomes following medial unicompartmental knee arthroplasty: current concepts

2020 ◽  
Vol 5 (4) ◽  
pp. 224-228 ◽  
Author(s):  
Stephanie C Petterson ◽  
Travis D Blood ◽  
Kevin D Plancher
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Surgical Techniques ◽  
Varus Deformity ◽  
Patient Specific ◽  
Unicompartmental Knee ◽  
Patient Specific Instrumentation ◽  
Alignment Correction ◽  
Medial Unicompartmental Knee Arthroplasty ◽  
The Impact

Unicompartmental knee arthroplasty (UKA) has become increasingly more common, indicating the necessity to better understand factors that may impact outcomes and survivorship. Overcorrection or undercorrection of a varus deformity can increase the risk of postoperative complications including contralateral, lateral compartmental osteoarthritis, component loosening, and component wear following medial UKA. There is no general consensus on the amount of alignment correction to optimise outcomes. The purpose of this article is to provide an overview of the current literature related to alignment, intraoperative alignment correction, and the impact on outcomes and survivorship following medial UKA as well as to explore alternative surgical techniques including patient-specific instrumentation and robotic assistance when managing the varus-malaligned knee with medial UKA. Understanding each of these factors and how they interact is vital in providing patients with promising outcomes following UKA. The ideal alignment is unknown; however, the key is to avoid severe undercorrection and overcorrection of varus malalignment for superior outcomes following medial UKA.

scholarly journals Finite Element Study on the Preservation of Normal Knee Kinematics with Respect to the Prosthetic Design in Patient-Specific Medial Unicompartmental Knee Arthroplasty

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Yong-Gon Koh ◽  
Kyoung-Mi Park ◽  
Kyoung-Tak Kang
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Articular Surface ◽  
Computational Simulation ◽  
Knee Kinematics ◽  
Patient Specific ◽  
Loading Conditions ◽  
Unicompartmental Knee ◽  
Medial Unicompartmental Knee Arthroplasty ◽  
Knee Joint Kinematics

Alterations in native knee kinematics in medial unicompartmental knee arthroplasty (UKA) are caused by the nonanatomic articular surface of conventional implants. Technology for an anatomy mimetic patient-specific (PS) UKA has been introduced. However, there have been no studies on evaluating the preservation of native knee kinematics with respect to different prosthetic designs in PS UKA. The purpose of this study was to evaluate the preservation of native knee kinematics with respect to different UKA designs using a computational simulation. We evaluated three different UKA designs: a nonconforming design, an anatomy mimetic design, and a conforming design for use under gait and squat loading conditions. The results show that the anatomy mimetic UKA design achieves closer kinematics to those of a native knee compared to the other two UKA designs under such conditions. The anatomy memetic UKA design exhibited a 0.39 mm and 0.36° decrease in the translation and rotation, respectively, in the swing phase compared with those of the natural knee. In addition, under the gait and squat loading conditions, the conforming UKA design shows limited kinematics compared to the nonconforming UKA design. Our results show that the conformity of each component in PS UKA is an important factor in knee joint kinematics; however, the anatomy mimetic UKA design cannot restore perfect native kinematics.

scholarly journals Medial Unicompartmental Knee Arthroplasty Using Patient-Specific Instrumentation – Accuracy of Preoperative Planning, Time Saving and Cost Effectiveness

10.29007/n5l4 ◽  
2018 ◽  
Author(s):  
Gesine Seeber ◽  
Kristina Kolbow ◽  
Uwe Maus ◽  
Alexander Kluge ◽  
Djordje Lazovic
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Patient Specific ◽  
Surgical Time ◽  
Time Saving ◽  
Planning Time ◽  
Operation Costs ◽  
Unicompartmental Knee ◽  
Patient Specific Instrumentation ◽  
Medial Unicompartmental Knee Arthroplasty

Since the past few years, patient-specific instrumentation (PSI) has been greatly publicized in knee endoprosthetics. Manufacturers propose advantages such as better accuracy of fit and reduction of both surgical time and operation costs due to pre- operative prosthesis planning. Whether these proposed advantages are achieved in medial unicompartmental knee arthroplasty (UKA) remains unclear. This paper presents results from a retrospective analysis of 22 patients (24 knees) who were electively provided with a medial unicompartmental knee arthroplasty using patient- specific instrumentation.

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