title: Useful ultrasonographic evaluation of the medial meniscus as a feature predicting the onset of radiographic knee osteoarthritis.
abstract: OBJECTIVE
  Medial radial displacement (MRD) of the medial meniscus is a feature proving a dysfunction in the medial meniscus in osteoarthritis (OA) of the knee. MRD was measured in radiographic pre-OA knee and early osteoarthritis of the knee (early-OA) longitudinally using ultrasound (US) to investigate the characteristics involved in the onset and progression of OA.
  
  
  METHODS
  Fifty-five patients with pain on the medial side of the knee participated in the present study. It was possible to follow-up 46 patients for 5 years, and, thus, they were divided into 32 pre-OA patients (female: 59%, mean age: 69.0 years) and 14 early-OA patients (female: 78%, mean age: 74.4 years) based on radiography at the baseline time-point. MRD was measured in standing and supine positions at baseline and after 1 and 5 years using US. MRD corrected with the skeletal size, i.e., the medial displacement index (MDI), was analyzed. The pre- and early-OA groups were divided into subgroups at 5 years: stable and OA progression groups, following the Kellgren/Lawrence classification, and ⊿MDI (gap of the MDI between the standing and supine positions) were retrospectively compared between the subgroups at baseline, 1 and 5 years.
  
  
  RESULTS
  In the overall pre-OA group, MDI increased by 7% and 10% at 5 years in the supine and standing position, showing a significant increase (P = 0.044, 0.0147). ⊿MDI was significantly greater in the subgroup with OA progression in the pre- and early-OA groups (P = 0.02 and 0.03, respectively), and was continuously 6-7% in the pre-OA progression group, showing that the displacement rate was 2-fold or higher than in the stable group.
  
  
  CONCLUSIONS
  An increase in ⊿MDI on US may be an important risk factor for the disease stage progression of OA and useful as a feature predicting the onset of radiographic knee OA.
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Yonago, 36-1 Nishimachi, Yonago, Tottori, 683-8504 Japan. Electronic address: air-taiki@hotmail.co.jp.
authors.forename: Taiki
authors.initials: T
authors.lastname: Murakami
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Yonago, 36-1 Nishimachi, Yonago, Tottori, 683-8504 Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Enokida
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Yonago, 36-1 Nishimachi, Yonago, Tottori, 683-8504 Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Kawaguchi
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Yonago, 36-1 Nishimachi, Yonago, Tottori, 683-8504 Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Otsuki
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Yonago, 36-1 Nishimachi, Yonago, Tottori, 683-8504 Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Nagashima
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D004204:Joint Dislocations / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000209:etiology; D011237:Predictive Value of Tests; D012372:ROC Curve; D011859:Radiography / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D018608:Ultrasonography, Doppler / Q000379:methods*