| To investigate the changes of contact stress between the medial and lateral chambers of the knee joint before and after the operation of the fibula high osteotomy,we explored the effect of the high osteotomy on the biomechanics of the knee joint.6 high-amputated specimens with foot and 10 cm above the knee joint were collected.The specimens were intact and the knee joint was normal.X-ray examination showed no bone abnormality.Specimens in vitro 2-4h in-80℃ in a deep low temperature refrigerator.The samples were thawed in a refrigerator at 4°C for 24 hours prior to the experiment and then continued for 12 hours at room temperature.After thawing,the knee was subjected to flexion and extension activities 200 times to ensure that the specimens were close to the physiological state of normal knee joint.When the specimen is fixed,the specimen is placed in the natural state of the machine on the biomechanical testing machine,and then the foot first fixed on the table in the self-made splint.We adjust the lower limb line of force to keep the lower limbs in the frontal and sagittal in a neutral position.The proximal femur is fixed in the groove of the top of the biomechanical test machine,and the lower limb is kept upright at the time of fixation.The position of the foot rotation can be adjusted according to the position condition so as to be closer to the natural position.In the patellar ligament on both sides of the joint at the longitudinal incision of the skin,we separated the soft tissue,cut the joint capsule,and reveal the joint space.We measures the size and shape of the medial and lateral tibial plateau using a temper.We control biomechanical testing machine to meet experimental conditions by computer.The bilateral pressure sensitive pieces were cut into corresponding shape,and then were placed inside and outside the joint gap.Axial pressure(400N)for 60 s,and unloading pressure within 5s,and then was removed the pressure sensitive film.The same experimental conditions repeated again.The same specimen,the same state,in the fibular head 7cm using pendulum saw about 2cm about the fibula.Repeat the above operation twice under the same experimental conditions.The pressure-sensitive tablets were divided according to the serial number of different specimens,and the data were analyzed by special instruments and software.The pressure of the medical and lateral chambers of the knee were measured in both cases of fibular integrity and high osteotomy Sensitive film of the color area.Last,we obtained the pressure value.After the experiment found.that the interphalangeal pressure before and after fibular osteotomy was(1.194 ± 0.285 VS.1.607 ± 0.296)×106Pa.The contact area of lateral compartment was(1.144 ± 0.3338 VS.1.551 ± 0.264)10-4m2.The lateral compartment pressure was(1.328 ± 0.383 VS.2.468 ± 0.629)N.There was significant difference between the two groups(P <0.05).And The medial compartment pressure was(1.966 ± 0.173 VS.1.572 ± 0.267)×106Pa,and the medial compartment pressure was(4.057 ± 0.641 VS.2.699 ± 0.610)×102N,and the difference between the two groups was statistically significant(P <0.05).By contrast,the contact area of the medial compartment was(2.083 ± 0.274 VS.1.728 ± 0.336 N,P> 0.05)×10-4m2.And There was no significant difference between the two groups(0.725 ± 1.117 VS.-1.412 ± 1.131)mm.The displacement of the lateral tibial plateau(0.945 ± 1.003 VS.-0.493 ± 0.754 mm,P <0.05).Following the fibula osteotomy,the lateral tibial plateau force,area and pressure increased.However,the medial tibial plateau force and the pressure were significantly reduced.And the peak value of force between lateral and medial chamber was deviated to the lateral chamber.Present results suggested that the fibula is of importance to a supporting role of the integrity of the lateral tibial plateau.That is induced to medial knee osteoarthritis.Our results reveals that the fibula osteotomy can effectively treat osteoarthritis.This is the biological mechanism of fibular osteotomy in the treatment of medial knee osteoarthritis. |
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