Radiographic grading of femoral stem cementation in hip arthroplasty

OBJECTIVE To determine intra and interobserver agreement of the grading system for femoral cementation in hip arthroplasty proposed by Barrack. METHODS Immediate anteroposterior and lateral postoperative radiographs of 55 primary total hip arthroplasties were assessed by two observers familiar with the use of this grading system. The assessments were performed on two separate occasions by each observer and independently. The statistical analysis measured the Kappa coefficient, which determines the degree of agreement between tests with categorical variables. RESULTS Intraobserver Kappa coefficient varied from 0.43 to 0.68, demonstrating moderate to substantial strength of agreement; interobserver Kappa coefficient varied from 0.19 to 0.44, demonstrating slight to moderate strength of agreement. CONCLUSION Intra and particularly interobserver agreement are limited in this grading system, even when used by trained individuals. Level of Evidence III, Study of nonconsecutive patients; without consistently applied reference "gold" standard.