| Objective: High tibial osteotomy, especially the medial opening hightibial osteotomy because of the less of complications, safe and easy to operateand better clinical results, has been widely accepted by scholars in clinic. Hightibial osteotomy has become the effective surgical method for treatment ofmedial compartment osteoarthritis with varus deformity. The principle of thehigh tibial osteotomy is to correct the limb mechanical force line and transferthe load line to the lateral of the knee joint. Thereby reducing the medialcompartment pressure load distribution of the knee joint, the damagedarticular cartilage area could be repaired. High tibial osteotomy can relieve theknee pain, correction of the leg mechanical force line errors and improve themotor function of the knee joint, delay the time of accept of the kneearthroplasty due to the osteoarthritis.The purpose of this experimental was use the medial opening high tibialosteotomy model of the fresh knee joint specimen to study the pressuredistribution area of the medial and lateral tibiofemoral joint compartmentthrough the different corrective angle, which can be provide a theoretical basisfor treatment of the medial compartment osteoarthritis of the knee by medialopening high tibial osteotomy.Methods: Collect of eight fresh-frozen knee specimens, including5malespecimens (2left knees and3right knees) and3female specimens (2leftknees and1right knee). The knee joint was amputated of upper and under ofthe specimens joint line20cm. All the knee specimens were no injury historyand surgery history. All the knee specimens underwent lateral X-rayexamination for exclusion of the anatomical abnormalities of the bone, bonedegenerative changes, rheumatoid arthritis-like changes, bone tumor andtumor-like illness. The fresh-frozen knee specimens were first placed in a4℃ refrigerator to thaw24hours, then placed in a room temperature environmentcontinue to thaw24hours before the experiment. And then dissection of theknee specimens, remove the skin and subcutaneous tissue around the kneespecimens, retain the integrity of the bone tissue and ligamentous structures.Knee specimens were fixed on the knee fixture and the knee joint maintain offlexion90°. Then begin performance the medial opening high tibialosteotomy under genuflex of90°. The medial opening high tibial osteotomywas from the tibial side of the proximal tibia about3cm under the joint lineand above the tibial tubercle to the proximal tibiofibular joint upper. Thelateral cortical bone can’t be completely desected. And we should preserve theportion continuity of the lateral cortical bone. The osteotomy gap wasgradually opened by the bone chisel. Then put the different sizes wood wedgeinto the osteotomy gap to achieve the desired correction angle of the limbalignment. We will divide the correction angle into three angles, respectively,5°,10°and15°. When the knee force line correction angle adjustment wasappropriate, fix the two osteotomy segments by the T-plate and metal screws.Then use of the self-curing denture acrylic and the self-curing liquid fordenture acrylic to embed fixation of the two ends of the knee specimens. Theproximal end of the femur and the distal end of tibiofibula of the knee wasfixed in a self-designed and manufactured experimental fixture, fine-tuningfixture, make the knee close to natural neutral position and keep the naturalneutral position. The knee was fixed on the CSS-44020biomechanicalequipment. And then connect the Tekscan pressure sensing system. TheTekscan pressure sensor was placed into the medial compartment of thetibiofemoral joint to measure the pressure of the medial tibiofemoralcompartment load and pressure distribution of the medial compartment area,then the Tekscan pressure sensor was placed into the lateral compartment ofthe tibiofemoral to measure the pressure load of the lateral compartment of thetibiofemoral joint. The knee specimens were repeated measure three times ineach of the correction angle, record the experimental data, and then take theaverage of the three times measured result as the final result. All data were using the SPSS13.0software for statistical analysis. Themedial compartment and lateral compartment pressure load was demonstratedby the mean±standard deviation in each correction angle. P<0.05wasdefined as significant difference.Results: When the lower extremity mechanical force line correction of0°, the pressure loading between the medial joint compartment was2.47±0.06MPa and the pressure loading between the lateral jointcompartment was2.28±0.06MPa. When the lower limb mechanical force linecorrection of5°, the medial compartment pressure was2.39±0.05MPa andthe lateral joint compartment pressure was2.33±0.06MPa, the medialcompartment pressure decreased by2.8%compared with the correction of0°and the lateral compartment pressure increased in2.1%compared with thecorrection of0°. When the lower extremity mechanical force line correctionof10°, the pressure loading between the medial joint compartment was2.35±0.03MPa and the lateral joint compartment pressure was2.38±0.06MPa, the medial compartment pressure decreased by4.9%compared with thecorrection of0°and the lateral compartment pressure increased in4.2%compared with the correction of0°. When the lower limb mechanical forceline correction of15°, the medial joint compartment pressure of2.30±0.02MPa and the lateral joint compartment pressure of2.49±0.04MPa, comparedto the correction of0°the medial compartment pressure decreased by6.9%and the lateral compartment pressure increase of8.4%. When correction of5°,10°and15°, the medial and lateral compartment pressure comparedwith correction of0°have a statistically significant difference (P<0.05).When correction of5°and15°, there was have a statistically significantdifference between the medial compartment and lateral compartment (P<0.05).When correction of10°, there was have no statistically significant differencebetween the medial compartment and lateral compartment (P>0.05)Conclusion: The lower limb mechanical force line change has asignificant effect on the pressure load distribution of the tibiofemoral joint.High tibial osteotomy can effectively correct the abnormal lower limb mechanical force line and improve the contact pressure load distribution of thetibiofemoral joint. With increase the angle of osteotomy, the pressure load ofthe medial compartment was gradually decreased, the pressure load of thelateral compartment was gradually increased. |
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