title: Osteonecrosis of the knee after laser or radiofrequency-assisted arthroscopy: treatment with minimally invasive knee arthroplasty.
abstract: BACKGROUND
  Osteonecrosis of the knee after various arthroscopic procedures associated with the use of laser or radiofrequency devices has been described in a few case reports. The purpose of this study was to report on a series of nineteen patients with osteonecrosis of the knee after arthroscopic procedures. A literature search was done to compare this series of patients to previously reported cases. In addition, we analyzed the outcome after treatment with minimally invasive knee arthroplasty.
  
  
  METHODS
  We studied patients who had development of osteonecrosis of the knee after a routine arthroscopic procedure. Preoperative and postoperative clinical notes, radiographs, and magnetic resonance images of patients were analyzed. Only those patients with no evidence of osteonecrosis on preoperative magnetic resonance imaging who later had development of osteonecrosis and subsequently required a knee arthroplasty were included. We conducted a search of the current literature to compare the results seen in our patient population with those seen in other patients with this entity. Patients were followed both clinically and radiographically for a mean of sixty-two months.
  
  
  RESULTS
  A total of nineteen patients met the inclusion criteria. There were fourteen women and five men with a mean age of sixty-nine years. Six patients underwent an arthroscopy with associated holmium or yttrium-aluminum-garnet laser treatment, ten patients had associated radiofrequency treatment, and three patients had microfracture surgery. Subsequent arthroplasty procedures included four unicompartmental knee arthroplasties and fifteen tricompartmental knee arthroplasties. At the time of final follow-up, the mean Knee Society objective score was 95 points.
  
  
  CONCLUSIONS
  Arthroscopic procedures may play a role in the development of osteonecrosis of the knee. To our knowledge, this is the largest series of patients to have development of this condition after arthroscopy with associated laser, radiofrequency, or microfracture surgery. The midterm results of knee arthroplasty in this unique patient population are comparable with those of patients undergoing knee arthroplasty for osteoarthritis of the knee.
  
  
  METHODS
  Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Bonutti
authors.forename: Thorsten M
authors.initials: TM
authors.lastname: Seyler
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Delanois
authors.forename: Margo
authors.initials: M
authors.lastname: McMahon
authors.forename: Joseph C
authors.initials: JC
authors.lastname: McCarthy
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mont
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001182:Arthroscopy / Q000009:adverse effects* / Q000379:methods; D004564:Electrocoagulation / Q000009:adverse effects*; D005260:Female; D005269:Femur; D005500:Follow-Up Studies; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery*; D012189:Retrospective Studies; D013977:Tibia