title: Comparison of anatomic vs. straight femoral stem design in total hip replacement - femoral canal fill in vivo.
abstract: BACKGROUND
  The femoral canal fill between an anatomic and a straight prosthesis design in cementless total hip arthroplasty (THA) was compared. We hypothesised that the anatomic SPS stem has higher proximal fill and lesser distal fill than the straight stem.
  
  
  METHODS
  The femoral canal fill was measured on 3 months routine postoperative x-rays at 5 levels of the stem in 50 consecutive patients, aged 35-83 years, who underwent 56 THA procedures by a single surgeon in this hospital. 22 patients received a straight design Ceramconcept Global stem, 34 patients received an anatomic design Symbios SPS stem. Both anteroposterior (AP) and lateral x-rays were combined to suggest a 3-D measurement.
  
  
  RESULTS
  On the AP x-rays, the canal fill was significantly higher using the anatomic design stem at the proximal measurement levels, and was significantly higher at the distal levels using the straight stem. With the AP and lateral x-rays combined, the canal fill at the proximal levels was also significantly higher in the anatomic groups, nonsignificantly lower at the central level and significantly lower at the distal levels.
  
  
  CONCLUSIONS
  In THA surgery, achieving high fill at the metaphysis of the femur and less fill at the diaphysis has been suggested to result in satisfactory outcome and high stability of the prosthesis. This study demonstrated that, compared to straight stem design, an anatomically designed stem has a significantly higher metaphyseal femoral canal fill.
authors.affiliation: Orthopaedic Surgery and Traumatology, Pitié-Salpêtrière Hospital, Paris - France.
authors.forename: Friso A
authors.initials: FA
authors.lastname: de Boer
authors.affiliation: Orthopaedic Surgery and Traumatology, Pitié-Salpêtrière Hospital, Paris - France.
authors.forename: Elhadi
authors.initials: E
authors.lastname: Sariali
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000601:surgery; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011859:Radiography; D012189:Retrospective Studies; D055815:Young Adult