PURPOSE: The objective of this study was to determine the effect of patellar morphology and implant design on patellofemoral contact stress in total knee arthroplasty (TKA) without patellar resurfacing. METHODS: Radiographic investigation: One hundred and fifty-seven knees of 127 patients were included in the study. Implants used in the present series were Low Contact Stress (LCS), Genesis II and NexGen. The relationship between the pre-operative patellar facet angle and newly identified post-operative osteosclerosis was assessed. Finite element analysis: Using patient-specific patellar three-dimensional finite element models, the relationship between the patellar facet angle and mean von Mises stress within the patella was calculated at flexion angles of 15°, 45°, 75° and 105°. RESULTS: Radiographic investigation: Post-operative osteosclerosis was observed with decreasing patellar facet angle in the Genesis II (odds ratio = 0.72; 95% confidence interval, 0.55-0.93; P = 0.012) and NexGen implants (odds ratio = 0.87; 95% confidence interval, 0.77-0.99; P = 0.029). Patients treated with the Genesis II had significantly more advanced osteosclerosis than those treated with the other two implants. Finite element analysis: A negative correlation was found between the patellar facet angle and the mean von Mises stress for all three implants. The Genesis II showed significantly higher von Mises stress than the other two implants at flexion angles of 15°, 45° and 105°. CONCLUSIONS: Both patellar morphology and femoral component geometry influence patellofemoral contact stress in total knee arthroplasty without patellar resurfacing. LEVEL OF EVIDENCE: Case control study, Level III.
PURPOSE: The objective of this study was to determine the effect of patellar morphology and implant design on patellofemoral contact stress in total knee arthroplasty (TKA) without patellar resurfacing. METHODS: Radiographic investigation: One hundred and fifty-seven knees of 127 patients were included in the study. Implants used in the present series were Low Contact Stress (LCS), Genesis II and NexGen. The relationship between the pre-operative patellar facet angle and newly identified post-operative osteosclerosis was assessed. Finite element analysis: Using patient-specific patellar three-dimensional finite element models, the relationship between the patellar facet angle and mean von Mises stress within the patella was calculated at flexion angles of 15°, 45°, 75° and 105°. RESULTS: Radiographic investigation: Post-operative osteosclerosis was observed with decreasing patellar facet angle in the Genesis II (odds ratio = 0.72; 95% confidence interval, 0.55-0.93; P = 0.012) and NexGen implants (odds ratio = 0.87; 95% confidence interval, 0.77-0.99; P = 0.029). Patients treated with the Genesis II had significantly more advanced osteosclerosis than those treated with the other two implants. Finite element analysis: A negative correlation was found between the patellar facet angle and the mean von Mises stress for all three implants. The Genesis II showed significantly higher von Mises stress than the other two implants at flexion angles of 15°, 45° and 105°. CONCLUSIONS: Both patellar morphology and femoral component geometry influence patellofemoral contact stress in total knee arthroplasty without patellar resurfacing. LEVEL OF EVIDENCE: Case control study, Level III.
Authors: Thomas Jan Heyse; Christoph Becher; Nadine Kron; Sven Ostermeier; Christof Hurschler; Markus D Schofer; Carsten O Tibesku; Susanne Fuchs-Winkelmann Journal: Arch Orthop Trauma Surg Date: 2009-07-04 Impact factor: 3.067
Authors: R Stephen J Burnett; Julienne L Boone; Seth D Rosenzweig; Karen Steger-May; Robert L Barrack Journal: J Bone Joint Surg Am Date: 2009-11 Impact factor: 5.284
Authors: Lucas Werth; Mo Saffarini; Felix Amsler; Ashraf Abdelkafy; Michael T Hirschmann Journal: Knee Surg Sports Traumatol Arthrosc Date: 2016-09-13 Impact factor: 4.342
Authors: Ulf G Leichtle; Barbara Lange; Yvonne Herzog; Peter Schnauffer; Carmen I Leichtle; Nikolaus Wülker; Andrea Lorenz Journal: Appl Bionics Biomech Date: 2017-01-31 Impact factor: 1.781