Alignment of total knee arthroplasty: the relationship to radiolucency around the tibial component

Between January 1982 and July 1985, 122 cemented 'Accord' total knee replacements were performed. Out of this number, 21 were lost to follow-up because of death (in 16), revision (2) due to infection, and failure to attend (3). The post-operative alignment of 101 prostheses were compared to the incidence of radiolucencies around the tibial component at 5 years follow-up. The mechanical axis was used as a reference. The mean alignment was 0.99 degrees valgus with a standard deviation of 2.48 degrees. Some 72% of knees were within 3 degrees and 94% within 5 degrees of true alignment. Using two methods of assessing radiolucencies there was a non-significant relationship between the alignment and radiolucencies. The alignment tolerance with this prosthesis is, therefore, at least 5 degrees.