title: The effects of varus tibial alignment on proximal tibial surface strain in total knee arthroplasty: The posteromedial hot spot.
abstract: The aim of this study was to determine the effect of varus tibial alignment on proximal tibial strain in total knee arthroplasty. Fourteen paired fresh-frozen cadaver tibiae had photoelastic coating applied. The right tibiae were cut in neutral alignment, and the left tibiae were cut in 5 degrees of varus. Components were cemented and loaded with 3 x body weight, varying medial to lateral load. Surface microstrain was measured. There was a statistically increased hot spot of highly concentrated strain in the posteromedial quadrant of the proximal tibia in varus-cut bones (P<.05). In neutral alignment, the strain was nearly equal medial and lateral. The increased strain observed helps elucidate the mechanism of increased failure rates of a total knee arthroplasty inserted in varus alignment. Neutral alignment may have a protective effect.
authors.affiliation: Duke University Medical Center, Division of Orthopaedic Surgery, Durham, North Carolina 27710, USA.
authors.forename: Gregory V
authors.initials: GV
authors.lastname: Green
authors.forename: Keith R
authors.initials: KR
authors.lastname: Berend
authors.forename: Michael E
authors.initials: ME
authors.lastname: Berend
authors.forename: Richard R
authors.initials: RR
authors.lastname: Glisson
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Vail
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure