title: A safe overhang limit for unicompartmental knee arthroplasties based on medial collateral ligament strains: an in vitro study.
abstract: Excessive tibial component overhang during unicompartmental knee arthroplasty (UKA) may cause medial collateral ligament (MCL) impingement, which, in turn, may lead to medial knee pain [Chau et al. Tibial component overhang 226 following unicompartmental knee replacement-does it matter? The Knee. 2009;16(5):310-3]. This study examines MCL loads in 6 human cadaveric knees for different levels of overhang using a robotic testing system. The results indicated no statistically significant difference between the baseline MCL load (no overhang) and the 2-mm overhang (P = .261). However, there were significant differences in MCL load between 2- vs 4-mm (P = .012) and 2- vs 6-mm overhang (P = .022). The loads were almost doubled from 2 to 4 mm of overhang. We conclude that, to minimize pain from excessive MCL loading, surgeons should avoid tibial component overhang greater than 2 mm in unicompartmental knee arthroplasties.
authors: Department of Surgery, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors: Ravindra
authors: R
authors: Gudena
authors: Mohammad Atarod
authors: MA
authors: Pilambaraei
authors: Jason
authors: J
authors: Werle
authors: Nigel G
authors: NG
authors: Shrive
authors: Cyril B
authors: CB
authors: Frank
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D001696:Biomechanical Phenomena; D002102:Cadaver; D017885:Collateral Ligaments / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D013314:Stress, Mechanical; D013977:Tibia / Q000601:surgery*