title: Epidemiological characteristics of patellofemoral osteoarthritis in elderly Koreans and its symptomatic contribution in knee osteoarthritis.
abstract: BACKGROUND
  Many studies have reported the prevalence of knee osteoarthritis (OA) but have invariably focused on the tibiofemoral (TF) joint and overlooked the patellofemoral (PF) joint. Accordingly, little epidemiological information is available regarding the PF OA. The purpose of the current study was to document the epidemiological characteristics of PF OA in elderly Koreans.
  
  
  METHODS
  Radiographic assessment was performed for 681 elderly (≥65 years old) Koreans recruited from a community, and symptom severity was evaluated using Western Ontario and McMaster Universities Index (WOMAC) and Short Form-36 (SF-36) scales. Prevalence of different categories of knee OA (isolated PF OA, isolated TF OA and combined PF and TF OA) was calculated. The symptoms of isolated PF OA group and non-OA group were compared.
  
  
  RESULTS
  The overall prevalence of OA was 22.0% in the PF compartment and 34.1% in the TF compartment. The prevalence of isolated PF OA, isolated TF OA, and combined PF and TF OA was 3.8%, 17.8%, and 19.2%, respectively. Female sex, aging, and obesity were not associated with isolated PF OA. No significant differences were found in any clinical outcome scales between the isolated PF and non-OA groups.
  
  
  CONCLUSIONS
  This study documents that OA in the PF joint is common in elderly Koreans, but isolated PF OA is rare. Demographic risk factors are not associated with isolated PF OA, suggesting that isolated PF OA may have a different pathophysiology from other types of knee OA. Our study also indicates that the presence of isolated PF OA should not be construed to be responsible for clinical symptoms.
authors.affiliation: Department of Orthopaedic Surgery, Pusan National University Yangsan Hospital, 20 Geumo-ro, Mulgeum-eup, Yangsan-si, Gyeongsangnam-do 626-770, Republic of Korea. Electronic address: dricarus@naver.com.
authors.forename: Hyung Joon
authors.initials: HJ
authors.lastname: Cho
authors.affiliation: Joint Reconstruction Center, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Republic of Korea. Electronic address: drkirangowda@gmail.com.
authors.forename: Kiran Kumar
authors.initials: KK
authors.lastname: Gn
authors.affiliation: Joint Reconstruction Center, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Republic of Korea. Electronic address: orthoped.kjy@gmail.com.
authors.forename: Jong Yeal
authors.initials: JY
authors.lastname: Kang
authors.affiliation: Department of Orthopaedic Surgery, Pusan National University Yangsan Hospital, 20 Geumo-ro, Mulgeum-eup, Yangsan-si, Gyeongsangnam-do 626-770, Republic of Korea. Electronic address: kuentak@pusan.ac.kr.
authors.forename: Kuen Tak
authors.initials: KT
authors.lastname: Suh
authors.affiliation: Joint Reconstruction Center, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Republic of Korea. Electronic address: osktk@snubh.org.
authors.forename: Tae Kyun
authors.initials: TK
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000453:epidemiology*; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging*; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: Elderly Koreans; Knee; Osteoarthritis; Patellofemoral joint; Prevalence