Bi-unicondylar arthroplasty: a biomechanics and clinical outcomes study
File(s)
Published version
Author(s)
Garner, Amy
Dandridge, Oliver
Amis, Andrew
Cobb, Justin
van Arkel, Richard Jan
Type
Journal Article
Abstract
Aims Bi-Unicondylar Arthroplasty (Bi-UKA) is a bone and anterior cruciate ligament (ACL) preserving alternative to Total Knee Arthroplasty (TKA) when the patellofemoral joint is preserved. The aim of this study is to investigate the clinical outcomes and biomechanics of Bi-UKA. Methods Bi-UKA subjects (N = 22) were measured on an instrumented treadmill, using standard gait metrics, at top walking speeds. Age, sex and BMI-matched healthy (N = 24) and primary TKA (N = 22) subjects formed control groups. TKA subjects with pre-operative patellofemoral or tricompartmental arthritis or ACL dysfunction were excluded. The Oxford Knee Score (OKS) and EuroQol-5D (EQ-5D) were compared. Bi-UKA then TKA were performed on eight fresh frozen cadaveric knees, to investigate knee extensor efficiency under controlled laboratory conditions, using a repeated measures study design. Results Bi-UKA walked 20% faster than TKA (Bi-UKA 6.70.9km/h, TKA 5.60.7km/h p<0.001), exhibiting nearer-normal vertical Ground Reaction Forces in maximum weight-acceptance and mid-stance, with longer step and stride lengths compared to TKA (p<0.05). Bi-UKA
subjects reported higher OKS (p=0.004) and EQ-5D (p<0.001). In vitro, Bi-UKA generated the same extensor moment as native knees at low flexion angles, whilst reduced extensor moment was measured following TKA (p<0.003). Conversely, at higher flexion angles, the extensor moment of TKA was normal. Over the full range, the extensor mechanism was more efficient following Bi-UKA than TKA (p<0.05). Conclusion Bi-UKA had more normal gait characteristics and improved patient reported outcomes, compared to matched TKA subjects. This can, in part, be explained by differences in extensor efficiency.
subjects reported higher OKS (p=0.004) and EQ-5D (p<0.001). In vitro, Bi-UKA generated the same extensor moment as native knees at low flexion angles, whilst reduced extensor moment was measured following TKA (p<0.003). Conversely, at higher flexion angles, the extensor moment of TKA was normal. Over the full range, the extensor mechanism was more efficient following Bi-UKA than TKA (p<0.05). Conclusion Bi-UKA had more normal gait characteristics and improved patient reported outcomes, compared to matched TKA subjects. This can, in part, be explained by differences in extensor efficiency.
Date Issued
2021-11-11
Date Acceptance
2021-09-15
Citation
Bone & Joint Research, 2021, 10 (11), pp.723-733
ISSN
2046-3758
Publisher
The British Editorial Society of Bone & Joint Surgery
Start Page
723
End Page
733
Journal / Book Title
Bone & Joint Research
Volume
10
Issue
11
Copyright Statement
© 2021 Author(s) et al. This is an open- access article distributed under the terms of the Creative Commons Attribution Non- Commercial No Derivatives (CC BY- NC- ND 4.0) licence, which permits the copying and redistribution of the work only, and provided the original author and source are credited. See https://creativecommons.org/licenses/by-nc-nd/4.0/.
Identifier
https://online.boneandjoint.org.uk/doi/full/10.1302/2046-3758.1011.BJR-2021-0151.R1
Subjects
Bi-unicondylar compartmental arthroplasty
EQ-5D scores
Gait and functional outcomes
Knee extensor biomechanics
Oxford Knee Scores
anterior cruciate ligament (ACL)
arthroplasties
flexion angles
knees
patellofemoral joint
patient-reported outcomes
total knee arthroplasty (TKA)
unicompartmental knee arthroplasty (UKA)
1103 Clinical Sciences
1106 Human Movement and Sports Sciences
Publication Status
Published
Date Publish Online
2021-11-11