title: Femoral Implant Design Modification Decreases the Incidence of Patellar Crepitus in Total Knee Arthroplasty.
abstract: Patellar crepitus is a complication most commonly seen in patients implanted with a posterior-stabilized total knee arthroplasty (TKA). Recently, design changes in the patellofemoral geometry and the intercondylar box ratio have been optimized in newer TKA designs. A comparative study was performed to analyze the incidence of patellar crepitus between a historical vs modern TKA design.
  
  
  
  A retrospective review of all patients at our institution that underwent a primary TKA with either a PFC Sigma or Attune posterior-stabilized TKA (DePuy, Inc, Warsaw, IN), with a minimum of 1-year follow-up duration was performed. A total of 1165 participants implanted with the PFC Sigma and 728 with the Attune design were analyzed. Patellar crepitus incidence, functional scores, and range of motion were recorded at each follow-up appointment. Statistical analyses were performed between the 2 groups to determine if there were differences in clinical outcomes.
  
  
  
  The incidence of crepitus in participants implanted with the Attune was 0.55% vs 6.26% in the PFC Sigma cohort (P < .001) at 1 year vs. 0.83% vs 9.4%, respectively at 2 years post operatively (P < .001). There were small differences in extension, flexion, and Knee Society Scores between the 2 groups that were not clinically meaningful.
  
  
  
  The Attune posterior-stabilized TKA demonstrated substantially less patellofemoral crepitus incidence than the historical control. We hypothesize that these findings are related to femoral component changes including a thinner and narrower anterior flange and a reduced femoral intercondylar box ratio.
authors.affiliation: Colorado Joint Replacement, Porter Adventist Hospital, Denver, Colorado.
authors.forename: J Ryan
authors.initials: JR
authors.lastname: Martin
authors.affiliation: Colorado Joint Replacement, Porter Adventist Hospital, Denver, Colorado.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Jennings
authors.affiliation: Colorado Joint Replacement, Porter Adventist Hospital, Denver, Colorado.
authors.forename: Tyler S
authors.initials: TS
authors.lastname: Watters
authors.affiliation: Colorado Joint Replacement, Porter Adventist Hospital, Denver, Colorado.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Levy
authors.affiliation: Raleigh Orthopaedic Clinic, Raleigh, North Carolina.
authors.forename: David Clinton
authors.initials: DC
authors.lastname: McNabb
authors.affiliation: Colorado Joint Replacement, Porter Adventist Hospital, Denver, Colorado; Department of Mechanical and Materials Engineering, University of Denver, Denver, Colorado; Department of Biomedical Engineering, University of Tennessee, Knoxville, Tennessee; Department of Orthopaedics, University of Colorado School of Medicine, Aurora, Colorado.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Dennis
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation; D003120:Colorado / Q000453:epidemiology; D005260:Female; D005269:Femur / Q000601:surgery; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000601:surgery; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012189:Retrospective Studies
keywords: crepitus; femoral component design; patellar clunk; posterior-stabilized; total knee arthroplasty