title: Juxta-articular bone marrow signal changes on magnetic resonance imaging following arthroscopic meniscectomy.
abstract: OBJECTIVE
  Postmeniscectomy osteonecrosis of the knee has been reported in the past decade but the etiology remains unclear. Some investigators have indicated that bone marrow signal changes evident on magnetic resonance imaging (MRI) could be early warning signs of osteonecrosis. The purpose of this study was to determine the incidence rate, location, and magnitude of such changes in bone marrow of the knee after arthroscopic meniscectomy, using MRI.
  
  
  METHODS
  Cohort analytic study.
  
  
  METHODS
  Ninety-three patients with no bone marrow signal abnormalities on preoperative MRI were examined after isolated arthroscopic meniscectomy. There were 51 men and 42 women with an age range of 11 to 62 years (mean, 36.6 years). Of the total, 57 patients underwent partial meniscectomy (34 medial and 23 lateral) and the others total meniscectomy (10 medial and 26 lateral). MRI examinations were performed independently of postoperative knee symptoms, 1 to 24 months after surgery. Bone marrow changes of the treated knees were evaluated by T1- and T2*-weighted MRI.
  
  
  RESULTS
  Thirty-two of 93 patients (34%) had bone marrow signal changes in femoral or tibial condyles shown on postoperative MRI. No patients had these changes in the femoral or tibial condyles opposite from the meniscectomy side and, in the majority of cases, the size was less than half that of the condyle. Fifteen of the 44 patients who underwent medial meniscectomy and 17 of the 49 patients who underwent lateral meniscectomy had such changes. The meniscectomy side did not affect the incidence rate, and frequently both femoral and tibial condyles were involved. Age, gender and articular cartilage condition at the surgery were not risk factors. In contrast, the extent of meniscectomy affected the incidence rate.
  
  
  CONCLUSIONS
  This study suggests a positive correlation between arthroscopic meniscectomy and postoperative bone marrow signal changes of the knee.
authors.affiliation: Gunma Sports Medicine Research Center, Zenshukai Hospital, Department of Orthopaedic Surgery, Gunma University Faculty of Medicine, Maebashi-shi, Gunma-ken, Japan.
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Masashi
authors.initials: M
authors.lastname: Kimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Higuchi
authors.forename: Masanori
authors.initials: M
authors.lastname: Terauchi
authors.forename: Kenji
authors.initials: K
authors.lastname: Shirakura
authors.forename: Kenji
authors.initials: K
authors.lastname: Takagishi
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000009:adverse effects*; D001853:Bone Marrow / Q000473:pathology*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007867:Leg Bones / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D010020:Osteonecrosis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D011184:Postoperative Period; D000070600:Tibial Meniscus Injuries