Abstract
The thrust plate prosthesis (TPP) is a femoral implant which stimulates physiological loading. This eliminates stress shielding, hence subsequent aseptic loosening of the femoral endo-prosthesis (Huggler/Jacob et al).
Between December 1994 and December 1999, TPP (third generation prototype) were inserted in 63 hips in 58 patients between the ages of 19 and 75.
This is a study and follow-up of one single surgeon. 46 hips in 41 patients were available for follow-up, clinical assessment (Harris Hip Score) and radiological evaluation (Buergi et al).
The average hip score improved from a pre-operative score of 39 to 94 postoperatively. All patients achieved their occupational status post-operatively.
Radiological evaluation assesses the cortical bone reaction in the mediocaudad zone of the femoral neck to the thrust plate. 36 hips (80%) maintained excellent osseous ingrowth between the mediocaudad femoral neck and the flat surface of the thrust plate (Type I reaction).
There were 3 loosenings (technical error/poor selections), 1 deep infection, 2 stress fractures, 9 (20%) myositis ossificans, 1 broken screw and no dislocations.
Implantation requires:
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pre-operative templating,
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careful precision with the preferred 130° of neck femoral shaft angle
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firm osseous fixation
Revision surgery, if required, is uncomplicated. It will be as for implanting a primary endo-prosthesis due to the preservation of excellent bone stock. The study shows promise of longevity and one hip arthroplasty for life, especially in young patients.
The abstracts were prepared by David AF Morgan. Correspondence should be addressed to him at davidafmorgan@aoa.org.au
Declaration of interest: a
