Preoperative coronal tibiofemoral subluxation does not affect 2-year outcomes after mobile-bearing medial unicompartmental knee arthroplasty for anteromedial osteoarthritis.
5 affiliations
- 1Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark. [email protected].
- 2Department of Orthopaedic Surgery, Ehime University Graduate School of Medicine, Toon, Japan. [email protected].
- 3Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark.
- 4Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
- 5Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
Abstract
Introduction
Coronal tibiofemoral subluxation (CTFS) is frequently observed in patients with medial knee osteoarthritis; however, its clinical relevance and the acceptable degree of CTFS when considering unicompartmental knee arthroplasty (UKA) remain unclear. This study aimed to determine whether preoperative CTFS influences short-term postoperative clinical outcomes in patients with anteromedial osteoarthritis (AMOA) undergoing medial UKA.Methods
In this retrospective cohort study, 457 consecutive knees with AMOA who underwent mobile-bearing UKA performed at a single center between August 2016 and May 2023 were analyzed. CTFS, defined as medial translation of the femur relative to the tibia, was measured on preoperative weight-bearing anteroposterior radiographs and expressed as the percentage of tibial plateau width. Patients were categorized into mild (0-5%), moderate (≥ 5% to < 10%), and severe (≥ 10%) CTFS groups. Clinical outcomes were evaluated using the Oxford Knee Score (OKS) preoperatively and at 3 months, 1 and 2 years postoperatively. Pairwise comparisons of changes in OKS were performed using a general linear model with Bonferroni-adjusted post hoc tests, and adjusted mean differences were calculated controlling for age, sex, body mass index, and preoperative OKS.Results
At 2 years, mean OKS improvements were 16.6 ± 8.9, 14.8 ± 8.3, and 16.0 ± 9.3 in the mild, moderate, and severe CTFS groups, respectively. Adjusted mean differences between groups were small, with confidence intervals including zero. The severe CTFS group demonstrated greater joint line convergence angle than the mild and moderate groups (both p < 0.001). Mean bearing thickness did not differ among groups (p = 0.428).Conclusions
Preoperative CTFS was not associated with worse outcomes in mobile-bearing UKA for AMOA with correctable deformity. Within the setting of correctable deformity and appropriate patient selection, preoperative CTFS was not associated with inferior 2-year outcomes. Longer-term survivorship and radiographic progression analyses are warranted.
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BibTeX
@article{kinoshita2026preoperative,
title = {{Preoperative coronal tibiofemoral subluxation does not affect 2-year outcomes after mobile-bearing medial unicompartmental knee arthroplasty for anteromedial osteoarthritis.}},
author = {Tomofumi Kinoshita and Kristine Ifigenia Bunyoz and Kristian R L Mortensen and Christian Bredgaard Jensen and Andrew Price and Kirill Gromov and Anders Troelsen},
journal = {Archives of orthopaedic and trauma surgery},
year = {2026},
month = oct,
doi = {10.1007/s00402-026-06530-x},
url = {https://europepmc.org/article/MED/42955360},
note = {CC BY},
}
RIS
TY - JOUR
TI - Preoperative coronal tibiofemoral subluxation does not affect 2-year outcomes after mobile-bearing medial unicompartmental knee arthroplasty for anteromedial osteoarthritis.
AU - Tomofumi Kinoshita
AU - Kristine Ifigenia Bunyoz
AU - Kristian R L Mortensen
AU - Christian Bredgaard Jensen
AU - Andrew Price
AU - Kirill Gromov
AU - Anders Troelsen
PY - 2026
DA - 2026/10/29
JO - Archives of orthopaedic and trauma surgery
DO - 10.1007/s00402-026-06530-x
UR - https://europepmc.org/article/MED/42955360
AB - Introduction Coronal tibiofemoral subluxation (CTFS) is frequently observed in patients with medial knee osteoarthritis; however, its clinical relevance and the acceptable degree of CTFS when considering unicompartmental knee arthroplasty (UKA) remain unclear. This study aimed to determine whether preoperative CTFS influences short-term postoperative clinical outcomes in patients with anteromedial osteoarthritis (AMOA) undergoing medial UKA.Methods In this retrospective cohort study, 457 consecutive knees with AMOA who underwent mobile-bearing UKA performed at a single center between August 2016 and May 2023 were analyzed. CTFS, defined as medial translation of the femur relative to the tibia, was measured on preoperative weight-bearing anteroposterior radiographs and expressed as the percentage of tibial plateau width. Patients were categorized into mild (0-5%), moderate (≥ 5% to < 10%), and severe (≥ 10%) CTFS groups. Clinical outcomes were evaluated using the Oxford Knee Score (OKS) preoperatively and at 3 months, 1 and 2 years postoperatively. Pairwise comparisons of changes in OKS were performed using a general linear model with Bonferroni-adjusted post hoc tests, and adjusted mean differences were calculated controlling for age, sex, body mass index, and preoperative OKS.Results At 2 years, mean OKS improvements were 16.6 ± 8.9, 14.8 ± 8.3, and 16.0 ± 9.3 in the mild, moderate, and severe CTFS groups, respectively. Adjusted mean differences between groups were small, with confidence intervals including zero. The severe CTFS group demonstrated greater joint line convergence angle than the mild and moderate groups (both p < 0.001). Mean bearing thickness did not differ among groups (p = 0.428).Conclusions Preoperative CTFS was not associated with worse outcomes in mobile-bearing UKA for AMOA with correctable deformity. Within the setting of correctable deformity and appropriate patient selection, preoperative CTFS was not associated with inferior 2-year outcomes. Longer-term survivorship and radiographic progression analyses are warranted.
SN - 0936-8051
SN - 1434-3916
ER -