To examine whether genetically determined factors can be used as predictors of requirement for knee joint surgery in the early phase of rheumatoid arthritis (RA).
We determined HLA-DRB1 alleles in 322 patients with seropositive RA by polymerase chain reaction and allele specific oligonucleotide probe techniques. Patients were classified into 3 groups (S/S, S/N, and N/N) based on their possession of two, one or no susceptibility alleles of RA, respectively. The stage of radiographic change in the knee joint determined using Larsen's standard film was compared to results of genotyping. Duration of RA before joint surgery in the 3 groups was also compared retrospectively.
The median number of years to develop to stages I, II, III, and IV and the number of years of disease duration before total knee arthroplasty (TKA) were significantly shorter in the S/S group than in the S/N and N/N groups (p < 0.05).
TKA was required earlier in the S/S group than in the S/N and N/N groups. This finding will affect planning of surgical management for RA based on anticipated courses.