title: Repair of retropatellar cartilage defects in the knee with microfracture and a cell-free polymer-based implant.
abstract: BACKGROUND
  To analyze magnetic resonance imaging (MRI) at 3T and the clinical outcome in a short-term pilot study after treatment of retropatellar cartilage defects with microfracturing and subsequent covering with the cell-free chondrotissue(®) polyglycolic acid-hyaluronan implant.
  
  
  METHODS
  Five consecutive patients after microfracturing and defect coverage with the chondrotissue(®) implant immersed with autologous serum were included. After a mean follow-up of 21 months (range 11-31 months), defect fill and repair tissue quality was assessed by 3-T MRI followed by applying established MRI scoring systems. The patients' situation was assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS) and a patients' satisfaction questionnaire.
  
  
  RESULTS
  Magnetic resonance imaging showed good to excellent defect fill with complete integration. The mean MOCART score was 61 (range 50-75) points. The mean Henderson score was 7 (range 6-9) points. All patients showed subchondral bone alterations. The KOOS showed good values in all sub-categories in 4 out of 5 patients and a mean overall score of 73 (range 40-90) points. Two patients rated the outcome as excellent, two as good and one as fair. All patients would have the procedure again and recommend it.
  
  
  CONCLUSIONS
  In this small case series, the coverage of symptomatic retropatellar cartilage defects with the chondrotissue(®) implant after microfracturing was safe and feasible with improvement of the patients' situation at short-term follow-up.
  
  
  METHODS
  IV, case series.
authors.affiliation: Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Becher
authors.forename: Max
authors.initials: M
authors.lastname: Ettinger
authors.forename: Marco
authors.initials: M
authors.lastname: Ezechieli
authors.forename: Christian
authors.initials: C
authors.lastname: Kaps
authors.forename: Marc
authors.initials: M
authors.lastname: Ewig
authors.forename: Tomas
authors.initials: T
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D054544:Arthroplasty, Subchondral / Q000295:instrumentation* / Q000379:methods; D002357:Cartilage Diseases / Q000473:pathology / Q000601:surgery*; D002358:Cartilage, Articular / Q000293:injuries* / Q000473:pathology / Q000601:surgery; D020099:Coated Materials, Biocompatible; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid; D015601:Injury Severity Score; D007718:Knee Injuries / Q000473:pathology / Q000601:surgery*; D007720:Knee Prosthesis; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D020370:Osteoarthritis, Knee / Q000473:pathology / Q000601:surgery*; D010865:Pilot Projects; D011100:Polyglycolic Acid; D012720:Severity of Illness Index; D014182:Transplantation, Autologous; D016896:Treatment Outcome; D014945:Wound Healing; D055815:Young Adult
chemical_list: D020099:Coated Materials, Biocompatible; D011100:Polyglycolic Acid; D006820:Hyaluronic Acid