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Increased patellofemoral pressure after TKA: an in vitro study
Ulf G Leichtle1, Markus Wünschel, Carmen I Leichtle
1Department of Orthopaedic Surgery, University Hospital Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
Summary
Patellar resurfacing in total knee arthroplasty (TKA) significantly increases patellofemoral pressure and reduces contact area. Preserving the native patella may be biomechanically preferable for patients without severe cartilage damage.
Area of Science:
- Orthopedic surgery
- Biomechanics
- Biomedical engineering
Background:
- Total knee arthroplasty (TKA) is a common procedure for knee osteoarthritis.
- Patellar resurfacing is a debated component of TKA due to potential biomechanical consequences.
- Previous studies on patellofemoral pressure distribution after TKA have yielded conflicting results.
Purpose of the Study:
- To simulate dynamic muscle-loaded knee flexion in cadaveric specimens.
- To analyze the influence of TKA with and without patellar resurfacing on patellofemoral pressure distribution.
- To investigate the biomechanical effects of patellar management in TKA.
Main Methods:
- Dynamic muscle-loaded knee flexion (15°-90°) was simulated in 22 cadaver knees using a specialized simulator.
- Patellofemoral pressures were measured using sensor foils (TEKSCAN).
- Patellofemoral offset was tracked using an ultrasound system (ZEBRIS).
Main Results:
- Maximal patellofemoral peak pressure increased significantly after TKA with an intact patella and even more after patellar resurfacing.
- The patellofemoral contact area decreased and shifted from a wide distribution to a punctate or line-shaped area post-TKA.
- Patellar resurfacing did not increase patellar thickness or alter patellofemoral offset.
Conclusions:
- Patellar resurfacing in TKA leads to a highly significant increase in patellofemoral pressure.
- The native patella's preservation appears biomechanically advantageous when severe patellar cartilage damage is absent.
- These findings suggest a need for careful consideration of patellar management in TKA based on biomechanical evidence.
