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Cohort studyJournal of orthopaedic science : official journal of the Japanese Orthopaedic Association · 2026

Medial-pivot total knee arthroplasty is associated with reduced perceived difficulty during stair descent than conventional designs: A propensity-matched cohort study.

Kazuhisa Hatayama, Satoshi Nonaka, Kazuya Okada … Masanori Terauchi

OrthopedicsCohort study

Medial-pivot total knee arthroplasty is associated with less perceived difficulty during stair descent.

Medial-pivot total knee arthroplasty is associated with reduced perceived difficulty during stair descent than conventional designs: A propensity-matched cohort study.

Kazuhisa Hatayama et al. · Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association · 2026

Background

Implant design in total knee arthroplasty (TKA) may influence knee stability and muscle demand during stair descent.

Purpose

This study compared postoperative stair-descent ability between medial-pivot (MP) TKA and conventional cruciate-retaining (CR) and posterior-stabilized (PS) TKA.

Methods

Female patients who underwent unilateral MP (EVOLUTION, MicroPort Orthopedics) or conventional CR/PS TKA (ATTUNE, DePuy Synthes) were retrospectively reviewed and propensity score-matched (1:1) for age, body mass index, and preoperative handgrip strength.

n = 164 patients

27%

Results

vs. 45%

fewer patients with medial-pivot knee replacement reported difficulty descending stairs

n = 164 patients

More results

Postoperative ROM in both knees was comparable between groups.

More results

In the conventional group, patients who descended using a step-over-step pattern demonstrated significantly greater preoperative handgrip strength and higher postoperative quadriceps strength than those who descended using a step-to-step pattern; however, no such differences were observed in the MP group.

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Conclusion · 1 of 2

MP TKA was associated with less difficulty during stair descent than conventional CR/PS TKA.

Conclusion · 2 of 2

Although the frequencies of step-over-step descent were similar, MP TKA enabled effective stair descent despite lower quadriceps strength, suggesting reduced muscular demand during weight-bearing flexion.

Medial-pivot total knee arthroplasty is associated with reduced perceived difficulty during stair descent than conventional designs: A propensity-matched cohort study.

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