Reproducibility of the Barrack and Gruen Grading Systems in Assessing Cement Mantle Quality in Hip Arthroplasty.

Abstract

Background: Aseptic loosening is the most common cause of failure of cemented femoral stems. This complication, which is directly related to cementation quality, can be assessed radiographically using the Gruen or Barrack bone cementation quality grading systems. However, the reproducibility of these grading systems is uncertain. The aim of this study was to determine the intra- and interobserver reproducibility of these two grading systems for the assessment of the bone-cement and cement-prosthesis interfaces.

Methods: Three observers independently evaluated bone cementation quality according to the Barrack and Gruen systems on radiographs obtained from 40 patients (80 radiographs; anterior-posterior [AP] and axial views) who had undergone cemented hip hemiarthroplasty after intracapsular femoral fracture. The 40 patients were randomly selected from 152 consecutive cases. The radiographs were evaluated twice over a 4-week period, once with the Barrack system and once with the Gruen system, in random order. In all cases, the same type of femoral stem and cement was used. The weighted kappa coefficient was determined to assess intraobserver and interobserver agreement.

Results: Most cases were classified as either Barrack B or C (72.8%). In the AP view, radiolucencies were present in 54.9% (95% CI: 46.6-63.1) of cases in the bone-cement interface (Gruen zones). For the Barrack system, the weighted kappa ranged from 0.42 to 0.57 for the intraobserver analysis and from 0.22 to 0.32 for the interobserver analysis, indicating a fair to moderate strength of agreement. The corresponding coefficients for the Gruen system were 0.40-0.55 (intraobserver) and 0.08-0.28 (interobserver), indicating a slight to moderate strength of agreement.

Conclusion: The findings of this study suggest that the Gruen and Barrack cementation grading systems are not sufficiently reliable to accurately evaluate cement mantle quality at the bone-cement and cement-prosthesis interfaces. Consequently, the routine use of these grading systems in hip orthopaedic practices should be reconsidered.Level of Evidence: Level IV.