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Updated: May 18, 2026
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Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat
Published on: November 9, 2018
Measured flexion following total knee arthroplasty.
Kenny T Mai1, Christopher A Verioti, Mary E Hardwick
1Hanford Community Medical Center, Hanford, California, USA.
Orthopedics
|October 3, 2012
Summary
Measuring knee flexion after total knee arthroplasty is crucial. Active versus passive measurements and clinical versus radiographic techniques yield significantly different results, impacting study findings.
Area of Science:
- Orthopedic surgery
- Biomechanics
Background:
- Postoperative knee flexion is vital for total knee arthroplasty (TKA) outcomes.
- Non-Western cultures often require higher knee flexion for activities like kneeling and squatting.
- High-flexion prosthetic designs aim to meet these increased demands.
Purpose of the Study:
- To compare active and passive knee flexion after TKA.
- To evaluate clinical (goniometer) versus radiographic (true lateral radiograph) measurement techniques.
- To assess differences across 5 prostheses (2 standard, 3 high-flexion) using independent examiners.
Main Methods:
- 108 patients (144 TKAs) with a mean follow-up of 2.7 years were studied.
- Active and passive flexion were measured using goniometers and true lateral radiographs.
- Measurements were taken by independent examiners for 5 different knee prostheses.
Main Results:
- Mean active flexion: 111° (clinical) and 109° (radiographic) for standard designs; 114° (clinical) and 117° (radiographic) for high-flexion designs.
- Mean passive flexion: 115° (clinical) and 117° (radiographic) for standard designs; 119° (clinical) and 124° (radiographic) for high-flexion designs.
- Statistically significant differences (P<.05) were found between measurement techniques (active vs. passive, clinical vs. radiographic).
Conclusions:
- Measurement methods significantly influence reported knee flexion outcomes after TKA.
- Standardized reporting of measurement techniques is essential for study reproducibility.
- Understanding measurement variability is key when evaluating TKA prosthesis performance.
