Abstract
Aims: Bone stock preservation is crucial when performing THR in young patients. Previous experiments have confirmed that a physiologic load transfer to the proximal femur has several advantages. First, there is experimental evidence (Fetto et al) that loading the medial and lateral flare effectively preserves in time metaphyseal bone stock. Second, biomechanical tests (Walker et al) have confirmed that with this kind of stress distribution it is possible to remove the diaphyseal portion of the stem.
Following this philosophy, an original ultra-short stem with extensive proximal load transfer was developed. Purpose of this paper is to present clinical and radiological results at 4 yrs average follow up.
Methods: Since June 1995, we implanted 118 stems in 101 patients. Average age at the time of surgery was 51 yrs (30-63) All operations were performed by the senior Author (FFS). Particular care was taken in preserving all the femoral neck and the trochanteric muscles. All implants were customised based on pre-operative CT data. Harris Hip Score (HHS) formed the basis of the clinical assessment. Serial post-operative AP and lateral radiographs were taken for all patients.
Result: Patients were followed-up for up to 9 years (mean follow-up 45 months) and results showed no stem related revisions or infections. The mean HHS increased from 44.8 pre-operatively to 98.6 post-operatively at the latest follow-up. Tight pain was recorded only in one case. Other complications included 2 dislocations, one trapped drain and 2 superficial wound infections. All stems appeared radiografically stable with a well maintained proximal bone stock. No radiolucent lines have appeared around the stem.
Conclusions: Results obtained in this group of relatively young patients have been encouraging. Clinical and radiographic results validate the assumption that torsional loads can be controlled even without the diaphy-seal portion of the stem. Neck preservation combined with lateral flare support guarantees a more natural loading of the femur. The absence of the stem makes this implant ideal for less invasive surgery.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
