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Gapping phenomenon of longitudinal meniscal tears
Lutz Dürselen1, Alexander Hebisch, Lutz E Claes
1Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, 89081 Ulm, Germany. lutz.duerselen@medizin.uni-ulm.de
Clinical Biomechanics (Bristol, Avon)
|June 28, 2003
Summary
Longitudinal meniscal tears gap minimally under typical knee loads, suggesting that current meniscal fixation implants are sufficiently strong for healing. This study clarifies meniscal tear behavior during joint loading.
Area of Science:
- Orthopedic biomechanics
- Sports medicine research
- Surgical implant analysis
Background:
- Meniscal fixation implants often exhibit low pull-out forces, raising questions about their in vivo efficacy.
- The gapping behavior of longitudinal meniscal tears under physiological loads remains largely uncharacterized.
Purpose of the Study:
- To investigate the gapping behavior of longitudinal meniscal tears.
- To determine the joint loading conditions that induce gapping in meniscal tears.
Main Methods:
- Longitudinal tears were created in porcine medial menisci.
- Knee joints underwent flexion-extension cycles under various axial loads and moments using a loading and motion simulator.
- Maximum tear gap size was measured under each loading condition.
Main Results:
- Maximum gapping of 1.59 mm occurred at 200 N axial joint load with combined valgus and external rotation moments.
- Internal tibial rotation moments consistently produced the smallest tear gaps across all tested loads.
Conclusions:
- The observed meniscal tear gapping suggests in vivo forces on fixation implants are low (approx. 8.4 N).
- Moderate joint loads result in minimal meniscal tear gapping, indicating low pull-out strength implants are unlikely to fail during normal rehabilitation.