[Comparative study between different radiographic plans in knee osteoarthritis]

Perform a comparative analysis (with the criteria of Ahlbäck original classification) of the anteroposterior (AP) weight-bearing radiograph of knee in extension and of Rosenberg(2) view, in symptomatic arthritic knees. The analysis aims at revealing agreement or disagreement between (AP) view and Rosenberg view and the degree of articular degeneration and the advantages of these views.

From January 2005 to March 2007, a prospective study was conducted with 76 selected patients (111 arthritic knees) attending the outpatient clinic, at the knee unit, and subjected to the radiographs proposed in the present study. Of the total number of patients (76), 52 were females and 24 males, having an average age of 62 (range, 50- 82 years). 41 patients had unilateral degeneration and 35 patients had bilateral degeneration. Of the total number of assessed knees (111), 66 were right knees and 45 were left knees. The study used the Kappa statistical analysis, which assesses interobserver agreement of qualitative data.

According to the Ahlbäck score, there was agreement between the orthopedist and the radiologist in 98.2% of cases in the AP weight-bearing view, and in 88.3% in the Rosenberg view. A highly significant agreement on both views between the orthopedist and the radiologist was noticed. However, the degree of agreement was higher for the AP weigh-bearing view than for the Rosenberg view. According to the Ahlbäck score, the AP weight-bearing view agreed with the Rosenberg view in only 27% of the cases for the orthopaedist, and in 31.5% for the radiologist. No significant agreement was found between the AP weight-bearing view and the Rosenberg view for the orthopedist and the radiologist.

There is no significant disagreement between experts concerning the classification of knee osteoarthritis, according to the Ahlbäck score, both for the AP weight-bearing view and the Rosenberg view. There is no agreement between the views, concerning the classification of knee osteoarthritis, both for the orthopedist and the radiologist, the Rosenberg view having shown more clearly the degree of articular degeneration. The posteroanterior view of Rosenberg provided a better assessment of degeneration of the articular surface, which in some cases led to a change in the classification of knee osteoarthritis and was routinely used.