Table 1 Peak and mean contact pressure between the patella and the trochlea in the healthy knee and the trochleodysplastic knee are shown “preoperative” and after simulated surgery at different flexion angles. Additionally, the patellar tilt and bisect offset values are included. * Welch’s t-test
Healthy knee | « Preoperative » | « 0.5x mean » | « mean » | « 1.5x mean » | |
|---|---|---|---|---|---|
Patellar tilt [°] | 12 | 18 | 9 | 7 | 5 |
Bisect offset [%] | 48.5 | 76 | 65 | 58 | 53 |
Flexion angle [°] | Peak [mPa] | Peak [mPa] | Peak [mPa] | Peak [mPa] | Peak [mPa] |
30 | 2.17 | 2.61 | 2.99/1.05 + 15%/+ 2% | 5.41 + 107% | 4.31 + 65% |
45 | 1.9 | 2.72 | 4.16/1.32 + 52%/+ 12% | 3.75 + 38% | 4.06 + 49% |
60 | 1.79 | 2.45 | 2.52/1.32 + 3%/+ 40% | 2.57 + 5% | 2.7 + 10% |
75 | 2 | 1.95 | 2.4/ 0.98 + 23%/+ 10% | 2.36 + 21% | 2.39 + 23% |
All angles | 1.97 (SD 0.16) | 2.43 (SD 0.34) | 3.3 (SD 1.01) | ||
Significance | P = 0.047* vs. healthy | P = 0.022* vs. preoperative | |||
Flexion angle [°] | Mean [mPa] | Mean [mPa] | Mean [mPa] | Mean [mPa] | Mean [mPa] |
30 | 0.85 | 1.03 | 1.05 + 2% | 1.2 + 17% | 1.36 + 32% |
45 | 0.78 | 1.18 | 1.32 + 12% | 1.37 + 16% | 1.44 + 22% |
60 | 0.74 | 0.94 | 1.32 + 40% | 1.24 + 32% | 1.41 + 50% |
75 | 0.76 | 0.89 | 0.98 + 10% | 1 + 12% | 1.06 + 19% |
All angles | 0.79 (SD 0.05) | 1.01 (SD 0.13) | 1.23 (SD 0.17) | ||
Significance | P = 0.016* vs. healthy | P = 0.033* vs. preoperative | |||