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Published on: September 7, 2022
Joint line changes after primary total knee arthroplasty: navigated versus non-navigated.
1Orthopaedic and Trauma Surgery Center, University Medical Center Mannheim of University Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany, Ahmed.Jawhar@umm.de.
Summary
Computer navigation does not improve joint line reconstruction accuracy in total knee arthroplasty (TKA). Conventional techniques provide precise results, making navigation unnecessary for restoring the natural joint line in primary TKA procedures.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Radiology
Background:
- Total knee arthroplasty (TKA) aims for accurate implant positioning.
- Focus has been on limb alignment, often neglecting joint line restoration.
- Navigation systems have been introduced to enhance TKA precision.
Purpose of the Study:
- To compare the accuracy of joint line restoration in primary TKA with and without navigation.
- To test the hypothesis that navigated TKA leads to more accurate joint line reconstruction.
Main Methods:
- A comparative study of 493 primary TKAs (206 navigated, 287 conventional).
- Joint line position assessed using calibrated standing radiographs (ap view).
- Modified Kawamura method used; >8 mm shift defined as outlier.
Main Results:
- Mean joint line shift was 0.7 mm (±4.4 mm) in conventional TKA and 0.6 mm (±4.5 mm) in navigated TKA.
- Outlier rates (>8 mm shift) were similar: 6% conventional vs. 6.8% navigated.
- No significant differences found in joint line shift or relation to leg alignment.
Conclusions:
- Conventional surgical techniques achieve precise joint line reconstruction in primary TKA.
- Navigation technology did not demonstrate an improvement in joint line reconstruction accuracy.
