Evidence map›Paper›PMID 41121108›Full record

Observational studyBMC musculoskeletal disorders2025

Knee extensor muscle strength, physical function and patient-reported outcomes the first year after total knee arthroplasty: a prospective longitudinal study.

Per Sjöström, Lena Nordeman, Ola Rolfson, Anette Larsson

Registry-linked trialAbstract readObservational Study
PubMed Full text at PMC Publisher
In one paragraph

Observational study in BMC musculoskeletal disorders, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05248815 (Knee Extensor Muscle Strength and Physical Function Before and After Total Knee Replacement), which is not on this map. Not yet cited in PubMed.

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0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT05248815 completednot on this map

Knee Extensor Muscle Strength and Physical Function Before and After Total Knee Replacement

TypeobservationalSponsorVastra Gotaland RegionRan2021 to 2023Enrolled57ConditionsArthropathy of Knee, Osteo Arthritis Knee
3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Per SjöströmPrimary Care Rehabilitation, Närhälsan Rehabilitation Centres, Lerum, Region Västra Götaland, Sweden. per.o.sjostrom@vgregion.se.
Lena NordemanDepartment of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Ola RolfsonDepartment of Orthopaedics, Institute of clinical sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Anette LarssonRegion Västra Götaland, Research, Education, Development and Innovation, Primary Health Care, Södra Älvsborg, Borås, Sweden.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundKnee extensor muscle strength is crucial for optimal knee function. Understanding the recovery process after total knee arthroplasty (TKA) and the impact of preoperative factors on recovery is therefore clinically significant. The primary aim was to investigate changes in knee extensor muscle strength in men and women during the first year after TKA. The secondary aim was to describe changes in physical function and patient-reported outcomes.

methodsA prospective observational study, with data collection before and at 12, 26 and 52 weeks after TKA. Participants (n = 57) were scheduled for elective primary TKA due to knee osteoarthritis. The primary outcome was changes in absolute and normalised maximum voluntary isometric contraction (AMVIC and NMVIC) for knee extensors in the operated knee, which was analysed with a linear-mixed effect model. Changes in physical function (6MWT and 30CST) were analysed with a paired samples t-test, and KOOS-scores were analysed with the Wilcoxon signed rank test.

resultsThe change in estimated marginal means for AMVIC at 12 weeks was − 27 N (95% CI -43;-11, p = .001) and − 3.1 percentage points for NMVIC (-5.7;-0.5, p = .013). At 52 weeks, the change was 42 N (21;63, p < .001) for AMVIC and 5.4 percentage points (2.1;8.6, p < .001) for NMVIC. The change at 26 weeks for AMVIC and NMVIC was not significant. AMVIC was affected by time, sex (both p < .001), statistical interaction between time and sex (p = .043) and the baseline covariates age (p = .010), BMI (p = .011) and 30CST (p = .048). NMVIC was affected by time, sex (both p < .001) and the baseline covariates BMI (p = .004), 6MWT (p = .023) and 30 CST (p = .036). 6MWT and KOOS-scores increased at all time points. 30CST increased from 26 weeks.

conclusionsBetter preoperative physical function and lower BMI appear beneficial for postoperative recovery of normalised knee extensor muscle strength. Following TKA, patient-reported outcomes (symptoms, pain, ADL and knee-related QoL) and gait performance appear to improve more rapidly than knee extensor muscle strength and 30CST. Preoperative exercise and weight loss (if obese), as well as continued postoperative exercise even if pain is alleviated and walking is improved may be advisable. TRIAL REGISTRATIONS: Retrospectively registered 9 February 2022 ( http://clinicaltrials.gov , ID: NCT05248815).

Indexed as

Arthroplasty, Replacement, KneeKnee JointMuscle StrengthOsteoarthritis, KneePatient Reported Outcome MeasuresAgedFemaleHumansIsometric ContractionLongitudinal StudiesMaleMiddle AgedProspective StudiesRecovery of FunctionTime FactorsTreatment OutcomeLongitudinal studiesMuscle strengthMuscle strength dynamometerPatient reported outcome measuresPhysical functional performancePhysical therapy specialtyPrimary health careQuadriceps muscleTotal knee arthroplasty

Identifiers

PMID41121108
PMCPMC12538749

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Registered trials

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.