全膝关节置换后关节线变化对髌股关节生物力学的影响

Effects of joint line changes on biomechanics of patellofemoral joint after total knee arthroplasty

BACKGROUND: In addition to infection, the reasons for total knee arthroplasty revision are polyethylene liner wear and prosthesis loosening. The impact of joint line height on patellofemoral biomechanics was inconclusive. OBJECTIVE: To study the impact of joint line changes after total knee arthroplasty on patellofemoral joint biomechanics. METHODS: Three-dimensional finite element models were established after total knee arthroplasty. The impact of different joint line height on quadriceps tensile force, patella tendon tension, and patellofemoral joint forces was calculated at range of flexion of 0°, 30°, 60° and 90°.  RESULTS AND CONCLUSION: (1) At knee flexion of 0°, the height of the joint line in -3 mm-4.5 mm did not have great impacts on quadriceps tensile force, patella tendon tension and patellofemoral joint forces. (2) At knee flexion of 30°-90°, the height of the joint line below 3 mm did not have great impacts on quadriceps tensile force, patella tendon tension and patellofemoral joint forces. The height of the joint line more than 3 mm had obvious impacts on quadriceps tensile force, patella tendon tension and patellofemoral joint forces. (3) It was recommended that the height of joint line in total knee arthroplasty was preferably controlled within 3 mm.