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Updated: Apr 5, 2026
In Vitro Application of a Wireless Sensor in Flexion-Extension Gap Balance of Unicompartmental Knee Arthroplasty
Published on: May 5, 2023
Do manual cutting guides for total knee arthroplasty introduce systematic error?
Erik Hohmann1,2, Kevin Tetsworth3,4
1Department of Orthopaedic Surgery, Clinical Medical School, University of Queensland, Brisbane, Australia. ehohmann@optusnet.com.au.
Introduction:
Conventional cutting guides in total knee arthroplasty can potentially cause unintentional deviation from the planned direction and depth of bone resection resulting in malaligned components. The purpose of this study was therefore to investigate the accuracy of bone cutting jigs for both the femur and tibia using imageless navigation.
Material And Methods:
A total of 125 patients with a mean age of 66.7 ± 9.9 years underwent primary total knee arthroplasty with a Stryker Triathlon™ fixed bearing posterior cruciate retaining implant using imageless navigation. Coronal and sagittal position of the secured cutting jig was recorded and bone resection was checked with a rectangular probe attached to a navigation tracker.
Results:
There were significant within group differences for the femoral sagittal cut (mean δ = 0.9° [31 %]; p = 0.00001), femoral depth medial compartment (mean δ = 0.5 mm [5 %]; p = 0.001), femoral depth lateral compartment (mean δ = 0.7 mm [7 %]; p = 0.00001), proximal tibial cut (mean δ = 0.3 mm [25 %]; p = 0.001), tibial depth medial compartment (mean δ = 0.6 mm [10 %]; p = 0.0001) and tibia depth lateral cut (mean δ = 0.4 mm [5 %]; p = 0.002). Deviation of more than 2° was observed for the distal cut in the sagittal plane in 17 % and in 9.6 % for the proximal tibial cut in the sagittal plane of all patients.
Conclusion:
The results of this study demonstrated significant differences between the dialed in cut and "actual" bone resection achieved for all planes for both the femur and tibia. The femur sagittal cut demonstrated a tendency for an extended cut and the tibia showed a tendency for varus.
Insights
Conventional cutting jigs in total knee arthroplasty showed significant deviations in bone resection accuracy for both femur and tibia. Imageless navigation revealed inaccuracies in all planes, impacting component alignment and surgical outcomes.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Surgical Navigation
Background:
- Conventional bone cutting jigs in total knee arthroplasty (TKA) risk unintentional deviations, potentially leading to malaligned components.
- Accurate bone resection is crucial for optimal TKA component placement and long-term implant survival.
Purpose of the Study:
- To investigate the accuracy of femoral and tibial bone cutting jigs during primary total knee arthroplasty using imageless navigation.
- To quantify deviations between planned bone cuts and actual resections in TKA.
Main Methods:
- 125 patients undergoing primary TKA with a specific implant system used imageless navigation.
- Coronal and sagittal jig positions were recorded; bone resections were verified using a navigation tracker probe.
Main Results:
- Significant differences were found between planned and actual bone resections for all planes in both femur and tibia.
- Femoral sagittal cuts showed a tendency for over-resection (extended cut), while tibial cuts tended towards varus alignment.
- Deviations exceeding 2° occurred in 17% of femoral distal sagittal cuts and 9.6% of tibial proximal sagittal cuts.
Conclusions:
- Bone cutting jigs demonstrate significant inaccuracies in achieving planned bone resections in TKA, even with imageless navigation.
- The observed deviations in femoral and tibial cuts can compromise component alignment.
- Further refinement of cutting jig design or navigation integration is warranted to improve TKA accuracy.
