title: Arthroscopic autologous chondrocyte implantation in osteochondral lesions of the talus: mid-term T2-mapping MRI evaluation.
abstract: OBJECTIVE
  Autologous chondrocyte implantation (ACI) in the ankle has become an established procedure to treat osteochondral lesions. However, a non-invasive method able to provide information on the nature of the repair tissue is needed. Recently, MRI T2 mapping was identified as a method capable of qualitatively characterizing articular cartilage. The aim of this study was to evaluate the mid-term results of a series of patients arthroscopically treated by ACI and investigate the nature of the repair tissue by MRI T2 mapping.
  
  
  METHODS
  Twenty patients, aged 35 ± 8 years, with an osteochondral lesion of the talus, underwent ACI and were evaluated at 5 ± 1 years' follow-up clinically (AOFAS score) and by the MRI T2-mapping sequence. MRI images were acquired using a protocol proposed by the International Cartilage Repair Society, evaluated by the MOCART score and completed by the T2-mapping sequence. Healthy volunteers, mean age 29 ± 6 years, were enrolled, and their T2 map values were used as a control. Their MRI results were then correlated with the clinical score.
  
  
  RESULTS
  The AOFAS score increased from 59 ± 16 pre-operatively to 84 ± 18 at follow-up (P < 0.0005). Patients with more than 4 years' follow-up were found to have the most satisfactory results. On the basis of the controls, healthy hyaline cartilage tissue showed a T2 map value of 35-45 ms. A mean T2 map value compatible with normal hyaline cartilage was found in all the cases treated, covering a mean percentage of 69% ± 22 of the repaired lesion area.
  
  
  CONCLUSIONS
  ACI was able to provide durable results that improved over time. Because of its ability to detect cartilage quality, the MRI T2-mapping sequence integrated with the Mocart score is a valid, non-invasive technique in evaluating the nature of the repair tissue in the ankle joint.
  
  
  METHODS
  Therapeutic study, Level IV.
authors.affiliation: Service of Ecography and Radiology, Rizzoli Orthopaedic Institute, Bologna, Italy.
authors.forename: Milva
authors.initials: M
authors.lastname: Battaglia
authors.forename: Francesca
authors.initials: F
authors.lastname: Vannini
authors.forename: Roberto
authors.initials: R
authors.lastname: Buda
authors.forename: Marco
authors.initials: M
authors.lastname: Cavallo
authors.forename: Alberto
authors.initials: A
authors.lastname: Ruffilli
authors.forename: Carlo
authors.initials: C
authors.lastname: Monti
authors.forename: Stefano
authors.initials: S
authors.lastname: Galletti
authors.forename: Sandro
authors.initials: S
authors.lastname: Giannini
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000473:pathology / Q000601:surgery; D001182:Arthroscopy / Q000379:methods*; D016022:Case-Control Studies; D017690:Cell Transplantation / Q000379:methods; D019902:Chondrocytes / Q000637:transplantation*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055034:Osteochondrosis / Q000175:diagnosis / Q000601:surgery*; D010147:Pain Measurement; D012016:Reference Values; D018709:Statistics, Nonparametric; D013628:Talus / Q000473:pathology / Q000601:surgery*; D014182:Transplantation, Autologous; D016896:Treatment Outcome