title: Analysis of bone mineralization on uncemented femoral stems by [18F]-fluoride-PET: a randomized clinical study of 16 hips in 8 patients.
abstract: OBJECTIVE
  We present the first study using fluoride-positron emission CT (F-PET/CT) to analyze mineralization of bone in the femur adjacent to uncemented stems following total hip arthroplasty (THA). We studied patients who were operated bilaterally for osteoarthritis with 2 different stems during the same surgical session.
  
  
  METHODS
  THA was performed bilaterally during the same surgical session in 8 patients with bilateral osteoarthritis of the hip. An SL-PLUS stem was inserted in one hip and a BetaCone stem was inserted in the contralateral hip, with randomization of side and sequence. A second group of 12 individuals with a normal healthy hip was used as reference for normal bone metabolism. Clinical and radiographic evaluation was performed preoperatively, postoperatively, and at 2 years. We used [18F]-fluoride-PET/CT to analyze bone mineralization adjacent to the stems 1 week, 4 months, and 12 months after surgery. We modified the Polar Map system to fit the upper femur for analysis and presentation of the PET results from 12 regions of interest adjacent to the whole stem.
  
  
  RESULTS
  The clinical results were good at 2 years. By radiography, all stems were stable. At PET analyses 1 week after surgery, the activity was higher for the SL-PLUS group than for the BetaCone group. The activity was statistically significantly higher for both stems than the reference values at 4 months, and was most pronounced in the upper femur. At one year, the activity had declined more for the BC group than for the SL group.
  
  
  CONCLUSIONS
  The bone mineralization activity varied between different regions for the same stem and between different time periods for each group. F-PET/CT is a novel and valuable tool for analysis of bone mineralization patterns around uncemented femoral stems in detail. The combination of PET/CT analysis and the modified Polar Map system may provide a useful tool for future studies of metabolic bone responses to prosthetic implants.
authors.affiliation: Department of Orthopedics, Gävle Hospital and Centre for Research and Development, Uppsala University/County Council of Gävleborg, Sweden. gosta.ullmark@lg.se
authors.forename: Gösta
authors.initials: G
authors.lastname: Ullmark
authors.forename: Olle
authors.initials: O
authors.lastname: Nilsson
authors.forename: Enn
authors.initials: E
authors.lastname: Maripuu
authors.forename: Jens
authors.initials: J
authors.lastname: Sörensen
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D016723:Bone Remodeling / Q000502:physiology*; D002113:Calcification, Physiologic / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D015207:Osteoarthritis, Hip / Q000601:surgery*; D049268:Positron-Emission Tomography; D011474:Prosthesis Design; D011475:Prosthesis Failure; D019275:Radiopharmaceuticals; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18