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Table 4 Surgical anatomical parameters relevant for HTO in humans and sheep

From: Basic science of osteoarthritis

  Human knee Sheep stifle joint Surgical consequences for the sheep HTO model
Tibial plateau width [mm] 60-70 46-56 match screw length, narrow and strait plate design necessary
Tibia valga [°] 0 3.5 valgus overcorrection more likely
Knee range of motion [°] 0-0-140 0-35-72 dorsal plate positioning after open wedge HTO suggested due to increased loading of the posterior tibial plateau
Tibial tuberosity dimension adding to the anterio-posterior diameter of the tibial head [%] 10-15 30-35 anterior plate misplacement more likely
Tibial tuberosity height distance in relation to the joint line [mm] 25-30 10-15 anterior plate misplacement more likely
Posterior slope of the posterior articular surface [°] 0-10 20 ± 3 narrow and straight plate design necessary for posterior placement
Biomechanical properties of the tibial head elastic cortical bone, exuberant amount of spongious bone brittle cortical bone, few spongious bone bicortical proximal screw placement mandatory to avoid fracture and dislocation, biplanar osteotomy mandatory regardless of the desired direction of correction
Musculature of the hind limb remote from bony knee structures voluminous on medial and lateral side of the femur distal femoral and proximal lateral tibial osteotomy almost impossible, stay on the medial side of the proximal tibia for any desired correction angle
Trochlea ridge lateral ridge extending further laterally and anteriorly medial ridge extending further cranially and dorsally than lateral ridge higher propensity of patella instability after valgus correction
  1. Case reports: + (seldom), ++ (infrequent), +++ (frequent), 1 (may depend on implant design)
  2. ° degree