title: Is the clinical outcome after cartilage treatment affected by subchondral bone edema?
abstract: OBJECTIVE
  Subchondral bone edema is a common finding after cartilage treatment, but its interpretation is still debated. The aim of this study is to analyse the presence of edema after matrix-assisted autologous chondrocyte transplantation (MACT) for knee cartilage lesions at different follow-up times and its correlation with the clinical outcome.
  
  
  METHODS
  Two hundred and forty-eight magnetic resonance imagings (MRIs) of patients treated with a hyaluronic acid-based MACT for lesions of the knee articular surface were considered. The MRIs belonged to 116 patients (mean age at surgery 28.6 ± 10.3 years, average defect size 2.4 ± 1.0 cm(2)), 57 affected by degenerative cartilage lesions, 27 traumatic and 32 were osteochondritis dissecans (OCD). MRI follow-up was performed from 6 to 108 months after treatment. Other than its presence or absence, the subchondral bone edema was evaluated using a 3-level grading considering extension and hyperintensity, and with the WORMS score edema classification. The IKDC subjective score was collected at the time of every MRI.
  
  
  RESULTS
  An analysis of the entire MRI group showed that edema is not constantly present through the follow-up, but presents a particular and well-defined trend. Edema was present within the first 2 years and was then markedly reduced or disappeared at 2 and 3 years (p = 0.044). Afterwards the level of edema increased again (p < 0.0005) and remained steadily present at medium/long-term follow-up. Patellar lesions presented significantly lower edema (p = 0.012), whereas OCD lesions presented more edema at all follow-up (p = 0.002) and a different trend, with an increasing level of edema over time. No correlation was found between edema and clinical outcome.
  
  
  CONCLUSIONS
  Edema after MACT is present during the first phases of cartilage maturation up to 2 years of follow-up, and then tends to disappear. However, after a few years, it tends to reappear. Less edema was found in the patella, whereas more edema was found in the OCD, where subchondral bone is primarily involved. Interestingly, the presence of edema was not correlated with a poorer clinical outcome. Whether this might be a prognostic factor at longer follow-up remains to be determined, but our results give some indication on what to expect on both MRI edema and clinical outcome after MACT.
  
  
  METHODS
  Case series, Level IV.
authors: Biomechanics Laboratory-II Clinic, Rizzoli Orthopaedic Institute, Via Di Barbiano, 1/10, 40136, Bologna, Italy, g.filardo@biomec.ior.it.
authors: Giuseppe
authors: G
authors: Filardo
authors: Elizaveta
authors: E
authors: Kon
authors: Alessandro
authors: A
authors: Di Martino
authors: Francesco
authors: F
authors: Perdisa
authors: Maurizio
authors: M
authors: Busacca
authors: Francesco
authors: F
authors: Tentoni
authors: Federica
authors: F
authors: Balboni
authors: Maurilio
authors: M
authors: Marcacci
mesh_terms: D000293:Adolescent; D000328:Adult; D001847:Bone Diseases / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D002357:Cartilage Diseases / Q000175:diagnosis / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D004487:Edema / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D014182:Transplantation, Autologous / Q000009:adverse effects; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D006820:Hyaluronic Acid