Evidence map›Paper›PMID 42538552›Full record

ArticleKnee surgery & related research2026

Age-stratified risk of major systemic complications following unicompartmental versus total knee arthroplasty: a nationwide cohort study.

Manabu Kawata, Shotaro Aso, Kohei Kawaguchi, Ryota Yamagami, Kenichi Kono, Shuji Taketomi, Hiroki Matsui, Kiyohide Fushimi, Hideo Yasunaga, Sakae Tanaka

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Article in Knee surgery & related research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

10 authors.

Manabu KawataDepartment of Orthopaedic Surgery, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan. manabukawata@hotmail.com.
Shotaro AsoDepartment of Health Services Research, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Kohei KawaguchiDepartment of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
Ryota YamagamiDepartment of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
Kenichi KonoDepartment of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
Shuji TaketomiDepartment of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
Hiroki MatsuiDepartment of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Kiyohide FushimiDepartment of Health Policy and Informatics, Institute of Science Tokyo Graduate School, Tokyo, Japan.
Hideo YasunagaDepartment of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Sakae TanakaDepartment of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.

Funding

The Ministry of Education, Culture, Sports, Science and Technology, Japan 23K19663The Ministry of Education, Culture, Sports, Science and Technology, Japan 25K12425The Ministry of Health, Labour and Welfare, Japan 23AA2003The Ministry of Health, Labour and Welfare, Japan 24AA2006
6 · The paper itself

Abstract

backgroundThe optimal surgical approach for knee arthroplasty remains under debate regarding reducing systemic complications. Although unicompartmental knee arthroplasty (UKA) is generally considered less invasive than total knee arthroplasty (TKA), it remains unclear whether this advantage persists across age groups. This study aimed to compare the risk of major systemic complications between UKA and TKA across age categories using a large-scale nationwide database.

methodsPatients who underwent UKA or TKA between July 2010 and March 2022 were identified from the Diagnosis Procedure Combination database in Japan. The primary outcome was a composite of postoperative in-hospital death and major systemic complications requiring additional interventions. Rates of postoperative red blood cell (RBC) transfusion were also evaluated as a secondary outcome. Stabilized inverse probability of treatment weighting (IPTW) using propensity scores was applied to compare outcomes between the groups.

resultsThe cohort included 36,235 UKA and 322,424 TKA cases. After stabilized IPTW adjustment, the composite outcome occurred less frequently after UKA than after TKA (risk ratio [RR] 0.65; 95% confidence interval [CI] 0.50-0.85; p = 0.001). The RBC transfusion rate was also reduced in the UKA group (RR, 0.09; 95% CI 0.08-0.11; p < 0.001). In subgroup analyses stratified by age (≤ 79 and ≥ 80 years), UKA was associated with a lower incidence of the composite outcome compared with TKA in patients aged ≤ 79 years (RR 0.48; 95% CI 0.34-0.68; p < 0.001), whereas no significant difference between UKA and TKA was observed among patients aged ≥ 80 years (RR 0.92; 95% CI 0.62-1.35; p = 0.670). The rate of RBC transfusion was lower in the UKA group across age groups (for ≤ 79 years, RR 0.07; 95% CI 0.05-0.09; p < 0.001; for ≥ 80 years, RR 0.12; 95% CI 0.10-0.14; p < 0.001).

conclusionsRBC transfusion rates were consistently lower following UKA across age groups. While UKA was associated with fewer major systemic complications than TKA in patients aged ≤ 79 years, no such difference was observed in patients aged ≥ 80 years. In very elderly patients, careful perioperative risk assessment remains essential when considering UKA, similar to that for TKA.

Indexed as

Diagnosis Procedure Combination databasePostoperative complicationPropensity scoreTotal knee arthroplastyUnicompartmental knee arthroplasty

Identifiers

PMID42538552
PMCPMC13428448

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