Evidence map›Paper›PMID 42159764›Full record

ArticleArchives of orthopaedic and trauma surgery2026

Radiolucent lines after robotic-assisted surface-matching kinematically aligned UKA: short-term incidence and lack of association with tibial alignment.

Junya Itou, Ayano Kuwasawa, Kotaro Nihei, Ken Okazaki

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Article in Archives of orthopaedic and trauma surgery, 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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4 · The record

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5 · Who and what money

Authors and funding

4 authors.

Junya ItouDepartment of Orthopaedic Surgery, Tokyo Women's Medical University, Tokyo, Japan. jun718@gmail.com.
Ayano KuwasawaDepartment of Orthopaedic Surgery, Saitama Cooperative Hospital, Saitama, Japan.
Kotaro NiheiDepartment of Orthopaedic Surgery, Saitama Cooperative Hospital, Saitama, Japan.
Ken OkazakiDepartment of Orthopaedic Surgery, Tokyo Women's Medical University, Tokyo, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeThis study investigated the clinical outcomes of robotic-assisted unicompartmental knee arthroplasty (UKA) performed using a surface-matching kinematic technique that restores native joint morphology without alignment constraints. The primary aim was to determine the incidence and distribution of radiolucent lines (RLLs), and the secondary aim was to evaluate short-term revision rates and clinical outcomes.

methodsThis retrospective cohort study reviewed 242 medial UKAs performed between November 2021 and August 2023 by the same high‑volume surgeon using a surface‑matching technique. Radiographic parameters and patient‑reported outcome measures (PROMs) obtained before and 1 year after surgery were assessed, with radiographic evaluation performed independently of the clinical outcome assessment. A cemented JOURNEY II Uni implant was used in all cases, with intraoperative surface mapping used to guide kinematic placement of components without alignment constraints.

resultsRLLs were seen in 21.9% of knees, exclusively on the tibial side and mainly in the most medial (zone 1: 14.8%, 95% confidence interval [CI] 10.9-19.9) and posterior regions (zone 9: 15.3%, 95% CI 11.3-20.3). A larger tibial component was the only independent predictor of RLLs (odds ratio 1.54, 95% CI 1.27-1.88; p = 0.04). All PROMs improved, with no differences between knees with and without RLLs. No revisions, infections, or major complications occurred during the short‑term (1‑year) follow‑up.

conclusionsIn kinematically aligned UKA performed with a surface‑matching technique without restricting tibial varus or posterior slope, RLLs appeared in 21.9% of cases and were concentrated medially on the anteroposterior view and posteriorly on the lateral view. Tibial component size was the only independent risk factor. Short‑term clinical outcomes improved similarly regardless of RLL presence. LEVEL OF EVIDENCE: Level IV.

Indexed as

Arthroplasty, Replacement, KneeOsteoarthritis, KneePostoperative ComplicationsRobotic Surgical ProceduresTibiaAgedAged, 80 and overBiomechanical PhenomenaFemaleHumansIncidenceKnee ProsthesisMaleMiddle AgedPatient Reported Outcome MeasuresRadiographyCORIkinematic alignmentknee osteoarthritisroboticssurface matching methodUnicompartmental arthroplasty

Identifiers

PMID42159764
PMCPMC13190772

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.