Medial opening wedge tibial osteotomy and the sagittal plane: the effect of increasing tibial slope on tibiofemoral contact pressure.
BACKGROUND
Altering the tibial slope in an anterior cruciate ligament-deficient knee has been shown to affect anterior-posterior tibial translation. The effects on articular contact pressure of altering tibial slope during a high tibial osteotomy are unknown.


OBJECTIVE
Performing an opening wedge osteotomy anterior to the midaxial line will increase tibial slope. Increasing tibial slope with a high tibial osteotomy in an anterior cruciate ligament-deficient knee redistributes tibiofemoral joint contact pressures onto the posterior tibial plateau.


METHODS
Controlled laboratory study.


METHODS
Medial opening wedge high tibial osteotomies were performed, and a plate fixation with a known diameter inset was placed along the medial tibia in an anterior position and a posterior position on 9 cadaveric knees. Medial and lateral tibiofemoral contact pressures were measured at the resulting 2 different tibial slopes in both ligament-intact and ligament-deficient states using thin electronic sensors.


RESULTS
Anterior plate application resulted in an increase in posterior tibial slope by an average of 6.6 degrees (P < .001) compared with posterior plate placement. After medial opening wedge high tibial osteotomy, the mean peak lateral tibiofemoral contact pressure (3.4 MPa) was significantly greater (P = .002) than was the mean peak medial pressure (2.6 MPa). In ligament-intact specimens, altering the tibial slope did not significantly shift peak contact pressures. However, in ligament-deficient knees, increasing tibial slope by an average of 5.5 degrees significantly redistributed the location of peak intra-articular pressure, shifting it posteriorly by 24% (P = .003).


CONCLUSIONS
Increasing tibial slope in anterior cruciate ligament-deficient knees with a high tibial osteotomy redistributes pressure into the posterior tibial plateau.


CONCLUSIONS
In knees with chronic anterior cruciate ligament deficiency, posteromedial compartment degeneration is observed. Inadvertent redistribution of contact pressure into this area may be a cause of pain and premature clinical failure after medial opening wedge tibial osteotomy.
Rodner
Craig M
CM
Department of Orthopaedics, Medical Arts and Research Building, University of Connecticut Health Center, Farmington, CT 06030, USA.
Adams
Douglas J
DJ
Diaz-Doran
Vilmaris
V
Tate
Janet P
JP
Santangelo
Stephen A
SA
Mazzocca
Augustus D
AD
Arciero
Robert A
RA
D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000503:physiopathology*; D053587:Arthrometry, Articular; D001860:Bone Plates; D002102:Cadaver; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D007593:Joint Instability; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011312:Pressure; D011859:Radiography; D013314:Stress, Mechanical; D013977:Tibia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*