Abstract
There is a report that higher failure rate in uncemented total knee replacement components due to loosening. However, uncemented fixation has been an attractive concept because of bone preservation and revision surgery, potential improved load transfer, and decreased surgical time. “Regenerex” is a porous titanium layer with excellent initial fixation, and the promise of providing favourable biological fixation. This is used with the Biomet Vanguard total knee replacement.
14 patients had undergone total knee replacement surgery comprising 11 men and three women with an average age of 63.07 years, and a body mass index of 30.33. Three of these patients required revision, because of tibial component loosening within 12 months of surgery. There were two men and one woman with an average age of 63.33 and BMI of 34.55. Clinically, patients developed pain and a gradual deformity as a result of a symmetrical collapse of the proximal tibial bony support surface.
Histopathology on the removed specimens shows the development of fibre cartilaginous metaplasia with evidence of necrotic bone. This was similar in all patients. There was no foreign body giant cell reaction, and no evidence of infection. The appearance was suggested of osteonecrosis, occurring gradually.
The incidence of frequency of this complication with this component in our experience is of concern, and the aim of this presentation is to determine whether this is a more widespread phenomenon.
