title: Radiological evaluation of cartilage after microfracture treatment: a long-term follow-up study.
abstract: BACKGROUND
  Recent literature revealed good short-term results after microfracturing (MFX) of isolated focal cartilage defects in the knee joint. Study purpose was a long-term evaluation of patients who received MFX through a multimodal approach, correlating clinical scores and morphological pre- and postoperative MRI-scans.
  
  
  METHODS
  Between 2000 and 2007 158 patients were treated with MFX for focal femoral or tibial defects at our department. Patients with instabilities, secondary surgical intervention, patellofemoral lesions, a plica mediopatellaris or more than one cartilage defect site and age >55 were excluded. 15 patients were included. Minimum postoperative follow-up (FU) was 18 months (18-78 m). Mean age at surgery was 45 years (27-54), mean FU-interval 48 months (18-78 m). Male to female ratio was 9:6. For clinical assessment the Knee Osteoarthritis Ou tcome Score (KOOS) and Lysholm Score were used, radiological evaluation was performed with radiographs and 3Tesla-MRI.
  
  
  RESULTS
  Clinical knee function was rated good to excellent in 1 patient, fair in 2 and poor in 10 patients. 2/15 patients received full knee replacement due to insufficient cartilage repair through MFX during FU period. Evaluation of pre- and postoperative MRI showed good cartilage repair tissue in 1 (7.7%), moderate repair in 2 (15.4%) and poor fill in 10 patients (76.9%). In these 10 patients the defect size increased. Average defect size preoperatively was 187 mm(2) (range 12-800 mm(2)) and postoperatively 294 mm(2) (40-800 mm(2)). The KOOS-Pain averaged 60 (39-94), KOOS-Symptoms 60.6 (21-100), KOOS-ADL 69 (21-91), KOOS-Sports 35.7 (5-60) and KOOS-QUL 37.2 (6-81). The average Lysholm Score was 73.9 (58-94). 10 patients showed a varus leg axis deviation (Ø 5.9°), 3 had a neutral alignment. The alignment correlated positively with KOOS and especially with the Lysholm Score.
  
  
  CONCLUSIONS
  Our study demonstrated that MFX as a treatment option for cartilage defect in the knee did not show the anticipated clinical and radiological long-term results. In 12 of 15 patients the cartilage defect size had increased after MFX, in 2 patients indicating full-knee replacement. Especially those with a leg malalignment >5° in varus were more prone to suffer from an increase in defect size. In our cohort the clinical scores correlated with the radiological findings.
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Chestnut Hill, MA 02467, USA. avonkeudell@partners.org
authors.forename: A
authors.initials: A
authors.lastname: Von Keudell
authors.forename: J
authors.initials: J
authors.lastname: Atzwanger
authors.forename: R
authors.initials: R
authors.lastname: Forstner
authors.forename: H
authors.initials: H
authors.lastname: Resch
authors.forename: T
authors.initials: T
authors.lastname: Hoffelner
authors.forename: M
authors.initials: M
authors.lastname: Mayer
mesh_terms: D000328:Adult; D054544:Arthroplasty, Subchondral; D002358:Cartilage, Articular / Q000473:pathology* / Q000648:ultrastructure*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000473:pathology / Q000601:surgery*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016896:Treatment Outcome