Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Arthroplasty - Hip
Abstract number: 24083
A NEW CONCEPT OF CEMENTLESS STEM FIXATION IN TOTAL HIP
ARTHROPLASTY: A RADIOSTEREOMETRIC ANALYSIS
Aljosa MATEJCIC 1 , Ante MULJACIC 2 , Slobodan TEPIC 3 , William Andrew HODGE 4 ,
Henrik MALCHAU 5 , Stephen BRESINA 3 , Dinko VIDOVIC 1
1 Sisters of Mercy Hospital, Zagreb (CROATIA), 2 Hospital for Traumatology, Zagreb
(CROATIA), 3 SCYON Orthopaedics Technology Center, Zurich (SWITZERLAND),
4 Jupiter Medical Center, Jupiter (UNITED STATES), 5 Massachusetts General
Hospital, Boston (UNITED STATES)
OBJECTIVES: Total hip arthroplasty is successful procedure, but revision burden
remains high, particularly in young patients. Scyon Orthopaedics, Au, Switzerland,
has developed a novel concept of cementless stem fixation that reduces long - term
influence of stress shielding on stability of THA. The Scyon THR Stem provides
anchorage through bony ongrowth from the medial cortex without coupling to the
lateral cortex. This results in near-physiological loading of the proximal femur that
diminishes stress shielding. Stability required for ongrowth is implemented by locking
mono-cortical screws tapped through the medial cortex and locked into the stem. The
aim of the study is to evaluate the stability of the Scyon THR Stem in- vivo.
METHODS: During implantation of the THA, insertions of Tantalum beads into
specific areas of pelvic bone and femur were performed for the purpose of
RSA.Patients were invited for follow-up examinations at 6 weeks, 6 months, 1 and 2
years after surgery. At follow-up examinations patients underwent RSA as well as
standard x-ray evaluation. RESULTS: The follow-up results of 8 patients have
shown excellent functional recovery and radiographically notable bony ongrowth from
the medial cortex without additional bony integration from the lateral cortex. RSA
shows that the stem subsidence is below the level of detection for the method (0.40
mm) with p< 0.05 by two-tailed t-test with 80% power. CONCLUSION: This implant
may decrease aseptic loosening of THA by a reliable and consistent fixation of the
femoral stem, which additionally diminishes stress shielding of the proximal femur.
34