Effect of Femoral Component Design on Patellofemoral Crepitance and Patella Clunk Syndrome After Posterior-Stabilized Total Knee Arthroplasty

Patellar Clunk Syndrome in Fixed-Bearing Posterior-Stabilised versus Cruciate-Substituting Prostheses

“…An improved press fit condylar posterior-substituting femoral component with a deeper trochlear groove and smooth transition of the inter-condylar box to better accommodate any peri-patellar fibrous nodule is recently available, and early studies showed that it decreases the frequency of patellar clunk syndrome. 13 One limitation of our study was the difficulty the patients experienced in separating the function of their 2 knees during assessment. To standardise comparisons, the Knee Society scores were measured at postoperative one year when patients had completed the entire rehabilitation programme and the knee range of movement had plateaued.…”

“…6 Patellar clunk syndrome has been reported in different models, especially in posterior-stabilised prostheses. [7][8][9][10][11][12][13] The cause of patellar clunk syndrome is multifactorial; the component design is one factor. Femoral components with larger intercondylar box ratios (defined as the ratio of the length of the intercondylar box to the anteroposterior size of the component) are more likely to be associated with patellofemoral complications.…”

Anterior knee pain following primary total knee arthroplasty

“…In addition to depth, the length of the trochlear groove can also improve overall patellar tracking by enabling a smooth transition from flexion to extension. Femoral components with a longer trochlear groove extend further proximally through the use of a longer anterior flange and allow for earlier capture of the patella in flexion, leading to a smoother articulation at earlier degrees of flexion [28,30] . Lateral tracking of the trochlear groove, facilitated by specific positioning of the femoral component, is also known to influence patellofemoral kinematics.…”

“…Therefore a deeper and longer trochlear groove that tracks more laterally promotes stable and secure tracking of the patella thus producing a more natural and anatomic patellofemoral articulation [25,28,31] . In addition to improved patellar tracking, some of these design features may also facilitate a decrease in the rate of patellofemoral crepitance and patellar clunk syndrome [30] . Historically, femoral prosthesis designs did not adequately replicate the trochlear groove due in part to the lack of appropriate congruent angle.…”

Patello-femoral clunk syndrome-current concepts

“…9 Femoral components with a deep trochlear groove and smooth transition of the intercondylar box appear to better accommodate any peripatellar fibrous nodule that may form after total knee arthroplasty. 10 PS designs included a high transition zone from the trochlear groove to the intercondylar box with an abrupt transition to the distal femoral articular Available online at www.sciencedirect.com ScienceDirect journa l h ome page: www.els evier.com /locate/jor geometry. 1 This transition zone by defining the intercondylar box ratio, as the intercondylar box height versus the anteriorposterior height of the femoral component.…”