Differences in gait kinetics and kinematics between patients with rotating hinge knee and cruciate-retaining prostheses: a cross-sectional study.
Takehiro Ohmi, Takumi Yamada, Sadaya Misaki and 4 others
PMID 36118659WHAT IT FOUND
Gait mechanics for rotating hinge knee implants matched cruciate-retaining ones, not healthy knees.
This suggests the restrictive implant corrects alignment to normal load levels, but small sample size and all-female cohort limit generalizability.
Key findings
01No significant difference in knee adduction moment or varus angle during gait between rotating hinge and cruciate-retaining implant groups.
02Rotating hinge and cruciate-retaining groups had significantly smaller knee adduction moments and varus angles than the osteoarthritis group, indicating alignment correction.
03Rotating hinge group walked significantly slower than the cruciate-retaining and young adult groups.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
All participants were female, so findings may not apply to males. Cross-sectional design cannot determine whether RHK patients recover gait mechanics at the same rate as CR patients. Very small sample sizes (n=7 per implant group) reduce statistical power and generalizability. Only comfortable-speed level walking was assessed; stair negotiation, sit-to-stand, and other functional tasks were not evaluated. KAM analysis controlled for gait speed, which may mask true biomechanical differences attributable to implant design alone.
Declared interests
One author received research support from Zimmer Biomet, the manufacturer of the NexGen RHK implant studied. The sponsor had no role in study design, data collection, analysis, or manuscript preparation. Other authors declared no conflicts.
The easy way to misread this
Do not assume rotating hinge knee patients have equivalent functional outcomes to cruciate-retaining patients across all activities. This study only assessed level walking at self-selected speed in a very small, all-female cohort at varying postoperative times, and did not evaluate higher-demand tasks like stairs or sit-to-stand where implant constraint may matter more.