title: Stem cell therapy for the treatment of early stage avascular necrosis of the femoral head: a systematic review.
abstract: BACKGROUND
  Avascular necrosis (AVN) of the femoral head (FH) is believed to be caused by a multitude of etiologic factors and is associated with significant morbidity in younger populations. Eventually, the disease progresses and results in FH collapse. Thus, a focus on early disease management aimed at joint preservation by preventing or delaying progression is key. The use of stem cells (SC) for the treatment of AVN of the FH has been proposed. We undertook a systematic review of the medical literature examining the use of SC for the treatment of early stage (precollapse) AVN of the FH, in both pre-clinical and clinical studies.
  
  
  METHODS
  Data collected included: Pre-clinical studies - model of AVN, variety and dosage of SC, histologic and imaging analyses. Clinical studies - study design, classification and etiology of AVN, SC dosage and treatment protocol, incidence of disease progression, patient reported outcomes, volume of necrotic lesion and hip survivorship.
  
  
  RESULTS
  In pre-clinical studies, the use of SC uniformly demonstrated improvements in osteogenesis and angiogenesis, yet source of implanted SC was variable. In clinical studies, groups treated with SC showed significant improvements in patient reported outcomes; however hip survivorship was not affected. Discrepancies regarding dose of SC, AVN etiology and disease severity were present.
  
  
  CONCLUSIONS
  Routine use of this treatment method will first require further research into dose and quality optimization as well as confirmed improvements in hip survivorship.
authors.forename: Rick L
authors.initials: RL
authors.lastname: Lau
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Perruccio
authors.forename: Heather M K
authors.initials: HM
authors.lastname: Evans
authors.forename: Safiyyah R
authors.initials: SR
authors.lastname: Mahomed
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Mahomed
authors.affiliation: Division of Orthopaedic Surgery, Toronto Western Hospital, 399 Bathurst Street EW 1-427, Toronto, Ontario M5T 2S8, Canada. rajiv.gandhi@uhn.ca.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Gandhi
mesh_terms: D000818:Animals; D018450:Disease Progression; D005271:Femur Head Necrosis / Q000473:pathology* / Q000628:therapy*; D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D033581:Stem Cell Transplantation / Q000379:methods*; D016896:Treatment Outcome