title: Quantitative assessment of the yield of osteoblastic connective tissue progenitors in bone marrow aspirate from the iliac crest, tibia, and calcaneus.
abstract: BACKGROUND
  It is well known that bone marrow aspirate from the iliac crest contains osteoblastic connective tissue progenitor cells. Alternative harvest sites in foot and ankle surgery include the distal aspect of the tibia and the calcaneus. To our knowledge, no previous studies have characterized the quality of bone marrow aspirate obtained from these alternative sites and compared the results with those of aspirate from the iliac crest. The goal of this study was to determine which anatomic location yields the highest number of osteoblastic progenitor cells.
  
  
  METHODS
  Forty patients were prospectively enrolled in the study, and separate bone marrow aspirate samples were harvested from the ipsilateral anterior iliac crest, distal tibial metaphysis, and calcaneal body. The aspirate was centrifuged to obtain a concentrate of nucleated cells, which were plated and grown in cell culture. Colonies that stained positive for alkaline phosphatase were counted to estimate the number of osteoblastic progenitor cells in the initial sample. The anatomic locations were compared. Clinical parameters (including sex, age, tobacco use, body mass index, and diabetes) were assessed as possible predictors of osteoblastic progenitor cell yield.
  
  
  RESULTS
  Osteoblastic progenitor cells were found at each anatomic location. Bone marrow aspirate collected from the iliac crest had a higher mean concentration of osteoblastic progenitor cells compared with the distal aspect of the tibia or the calcaneus (p &lt; 0.0001). There was no significant difference in concentration between the tibia and the calcaneus (p = 0.063). Age, sex, tobacco use, and diabetes were not predictive of osteoblastic progenitor cell yield.
  
  
  CONCLUSIONS
  Osteoblastic progenitor cells are available in the iliac crest, proximal aspect of the tibia, and calcaneus. However, the iliac crest provided the highest yield of osteoblastic progenitor cells.
  
  
  CONCLUSIONS
  The study demonstrated that osteogenic progenitor cells are available in bone marrow aspirate harvested from the tibia or calcaneus as well as the iliac crest. All three sites are easily accessed, with a low risk of adverse events. However, larger volumes of aspirate may be needed from the tibia or calcaneus to approach the yield of cells from the iliac crest.
authors.affiliation: Orthopedic Foot & Ankle Center, 300 Polaris Parkway, Westerville, OH 43082, USA. ofacresearch@orthofootankle.com
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Hyer
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Berlet
authors.forename: Bradly W
authors.initials: BW
authors.lastname: Bussewitz
authors.forename: Thomas
authors.initials: T
authors.lastname: Hankins
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Ziegler
authors.forename: Terrence M
authors.initials: TM
authors.lastname: Philbin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001854:Bone Marrow Cells / Q000166:cytology*; D002111:Calcaneus / Q000166:cytology*; D002452:Cell Count; D003239:Connective Tissue Cells / Q000166:cytology*; D005260:Female; D006801:Humans; D007085:Ilium / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology*; D013977:Tibia / Q000166:cytology*