title: MRI-guided percutaneous retrograde drilling of osteochondritis dissecans of the knee.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the feasibility of a new method for osteochondritis dissecans (OCD) treatment.
  
  
  METHODS
  Ten OCD lesions of the knee unresponsive to conservative management were treated with MRI-guided percutaneous retrograde drilling to reduce symptoms and promote ossification of the lesion. All lesions were located in distal femoral condyles. Only stable OCD lesions were included (preprocedural MRI grade I or II). Five lesions were of juvenile type and five lesions were of adult type OCD. All the patients had severe limitation of activity due to the OCD-related pain. By using a 0.23 T open MRI scanner and spinal anesthesia, percutaneous retrograde drilling of the OCD lesions was performed (3 mm cylindrical drill, one to three channels). Optical tracking and MRI imaging were used to guide instruments during the procedure. Mean postprocedural clinical follow-up time was 3 years. Eight patients had a post-procedural follow-up MRI within 1 year.
  
  
  RESULTS
  All the OCD lesions were located and drilled using the 0.23 T open MRI scanner without procedural complications. All the patients had pain relief, mean visual analog score (VAS) declined from 6 to 2. Follow-up MRI showed ossification in all lesions. Eight patients could return to normal physical activity with no or minor effect on function (Hughston score 3-4). Treatment failed in two cases where the continuation of symptoms led to arthroscopy and transchondral fixation.
  
  
  CONCLUSIONS
  [corrected] MR-guided retrograde OCD lesion drilling is an accurate, feasible, and effective cartilage-sparing techique in OCD management.
authors.affiliation: Department of Radiology, Oulu University Hospital, P.O. Box 50, 90029, Oulu, Finland. risto.ojala@odl.fi
authors.forename: Risto
authors.initials: R
authors.lastname: Ojala
authors.forename: Pekka
authors.initials: P
authors.lastname: Kerimaa
authors.forename: Martti
authors.initials: M
authors.lastname: Lakovaara
authors.forename: Pekka
authors.initials: P
authors.lastname: Hyvönen
authors.forename: Petri
authors.initials: P
authors.lastname: Lehenkari
authors.forename: Osmo
authors.initials: O
authors.lastname: Tervonen
authors.forename: Roberto
authors.initials: R
authors.lastname: Blanco-Sequeiros
mesh_terms: D000293:Adolescent; D002648:Child; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D010008:Osteochondritis Dissecans / Q000601:surgery*; D013525:Surgical Instruments; D016896:Treatment Outcome; D055815:Young Adult