Effect of Femoral Component Rotation and Patellar Design on Patellar Forces

Singerman, Robert; Pagan, Hector D.; Peyser, Amos; Goldberg, Victor M.

doi:10.1097/00003086-199701000-00044

Cited by 47 publications

(29 citation statements)

References 6 publications

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“…One would have to incorporate an elastic-foundation model or use a hybrid rigid-body finite element analysis (Heegaard et al, 2001;D'Lima et al, 2001;Fregly et al, 2003). Despite the fact that rigid-body contact was used to simulate knee joint biomechanics, the kinematics and kinetics were representative of those measured in cadaver knees, and our results agreed well with previously published cadaver studies as well as a prospective, randomized clinical trial (Miller et al, 2001;Armstrong et al, 2003;Anouchi et al, 1993;Pagnano et al, 2004;Singerman et al, 1997). However, only fixed-bearing kinematics and tibiofemoral forces were validated with experimental data.…”

Section: Article In Presssupporting

confidence: 84%

“…In addition, in flexion, malrotation of the femoral component affects tibial adduction/ abduction, which a rotating-bearing design cannot correct. Further evidence to support this is provided by a report that femoral component rotation had a greater effect on patellar contact forces in a design with lower tibiofemoral constraint than in a design with greater constraint (Singerman et al, 1997). With more constraint, the tibia tends to follow the rotation of the femoral component with reduced potential for change in distal extensor mechanism alignment.…”

Section: Article In Pressmentioning

confidence: 97%

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The effect of femoral component malrotation on patellar biomechanics

Kessler

Patil

Colwell

et al. 2008

Journal of Biomechanics

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Section: Article In Presssupporting

confidence: 84%

Section: Article In Pressmentioning

confidence: 97%

The effect of femoral component malrotation on patellar biomechanics

Kessler

Patil

Colwell

et al. 2008

Journal of Biomechanics

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“…In studying larger femoral component rotations, Singerman [25] found that 10" internal component rotation caused higher medial-lateral forces up to 95" knee flexion. Although they also studied 10" external component rotation, the results were not specifically reported and apparently did not produce a significant effect.…”

Section: Discussionmentioning

confidence: 99%

“…Singerman et al [24,25] and Petersilge et al [19] studied the patellofemoral force balance using load cells. Singerman et a].…”

Section: MC Miller Et A! I Journal Of Orthopaedic Research I 9 (20mentioning

confidence: 99%

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The effect of component placement on knee kinetics after arthroplasty with an unconstrained prosthesis

Miller

Zhang

Petrella

et al. 2001

Journal Orthopaedic Research

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The mechanical success of a total knee replacement demands stable patellar tracking without subluxation and, stable tracking, in turn, can depend largely on the medial-lateral forces restraining the patella. Patellar button medialization has been advocated as a means of reducing subluxation, and experimental evidence has shown femoral component rotation also affects medial-lateral forces. Surgeons have choices in femoral component rotation and patellar button medialization and must frequently make intra-operative decisions concerning component placement because of anatomical variations among patients. Thus, in seeking to minimize mediallateral patellar force, we examined the effects of patellar button medialization and external femoral component rotation. The study used an unconstrained total knee system implanted in nine cadaveric specimens tested on a knee simulator operating through flexion angles up to 100". Tests included all combinations of external femoral component rotation of 0", 2.5", and 5" and patellar placement at the geometric center and at 3.75 mm medial to the geometric center. A video-based motion analysis system tracked patellar and tibial kinematics while a six-component load cell measured patellofemoral loads. Repeated measures analysis of variance revealed a statistically significant decrease in the average medial-lateral force with button medialization but no significant change with femoral component rotation. Neither femoral component rotation nor patellar button medialization had an effect on the normal component of the patellar reaction force. External femoral component rotation did cause significant increases in lateral patellar tilt, in tibial varus angle, and in external tibial rotation. Button medialization caused significant increases in lateral patellar tracking, lateral patellar tilt and external tibial rotation. The results in medial-lateral patellar forces quantify the benefit of patellar button medialization and discount any benefit of femoral rotation. The change in tibial kinematics with patellar button medialization and femoral component rotation cannot be measured in vivo with current technology, and the precise clinical implications are unknown.

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Identifying alignment parameters affecting implanted patellofemoral mechanics

Fitzpatrick

Baldwin

Clary

et al. 2012

Journal Orthopaedic Research

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Complications of the patellofemoral (PF) joint remain a common cause for revision of total knee replacements. PF complications, such as patellar maltracking, subluxation, and implant failure, have been linked to femoral and patellar component alignment. In this study, a dynamic finite element model of an implanted PF joint was applied in conjunction with a probabilistic simulation to establish relationships between alignment parameters and PF kinematics, contact mechanics, and internal stresses. Both traditional sensitivity analysis and a coupled probabilistic and principal component analysis approach were applied to characterize relationships between implant alignment and resulting joint mechanics. Critical alignment parameters, and combinations of parameters, affecting PF mechanics were identified for three patellar designs (dome, modified dome, and anatomic). Femoral internal-external (I-E) alignment was identified as a critical alignment factor for all component designs, influencing medial-lateral contact force and anteriorposterior translation. The anatomic design was sensitive to patellar flexion-extension (F-E) alignment, while the dome, as expected, was less influenced by rotational alignment, and more by translational position. The modified dome was sensitive to a combination of superior-inferior, F-E, and I-E alignments. Understanding the relationships and design-specific dependencies between alignment parameters can aid preoperative planning, and help focus instrumentation design on those alignment parameters of primary concern.

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Effect of Femoral Component Rotation and Patellar Design on Patellar Forces

Cited by 47 publications

References 6 publications

The effect of femoral component malrotation on patellar biomechanics

The effect of femoral component malrotation on patellar biomechanics

The effect of component placement on knee kinetics after arthroplasty with an unconstrained prosthesis

Identifying alignment parameters affecting implanted patellofemoral mechanics

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