title: Pseudo-patella baja after total knee arthroplasty.
abstract: BACKGROUND
  One of the complications of total knee arthroplasty (TKA) which has not yet been directly addressed is pseudo-patella baja (PPB). True patella baja (PB) is present when the length of the patellar tendon becomes shorter. PPB is present when the patella tendon is not shortened, but the level of the joint line is elevated. This study was conducted to assess PPB in TKA.
  
  
  METHODS
  Sixty patients who had had a primary TKA at our center between 1995 and 2005 were included. The average follow-up was 27.5 months. The Knee Society Scoring (KSS), lateral knee x-rays and the Blackburne-Peel index were used for assessments.
  
  
  RESULTS
  Out of the 60 patients, 43 (72%) demonstrated no joint line elevation or patellar tendon shortening (group A). Fifteen patients (25%) had joint line elevation (group B), and both PB and PPB were present in 2 (3%) patients (group C). KSS was lower in groups B and C compared with group A, but this difference was not statistically significant. The average range of motion (ROM) in group A was significantly higher compared with either group B or C, and patients in groups B and C showed significantly more severe pain compared with group A (P<0.001).
  
  
  CONCLUSIONS
  PPB is not an uncommon finding after TKA and is associated with a statistically significant decrease in ROM and an increase in pain. Furthermore, KSS in the PPB group was less than in patients without PPB, although the difference was not statistically meaningful.
authors.affiliation: Akhtar Orthopaedic Research Center, Shahid Beheshti Medical University, Tehran, Iran.
authors.forename: Seyyed Morteza
authors.initials: SM
authors.lastname: Kazemi
authors.forename: Laleh
authors.initials: L
authors.lastname: Daftari Besheli
authors.forename: Alireza
authors.initials: A
authors.lastname: Eajazi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Miniator Sajadi
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Okhovatpoor
authors.forename: Ramin
authors.initials: R
authors.lastname: Farhang Zanganeh
authors.forename: Reza
authors.initials: R
authors.lastname: Minaei
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000209:etiology; D010329:Patella / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D011182:Postoperative Care; D011300:Preoperative Care; D011859:Radiography; D016059:Range of Motion, Articular