Abstract
Quality of cementation in the early postoperative period has been proven to be an indicator of long-term survival of the total hip arthroplasty. Cementation grading described by Barrack et al is widely used but has certain limitations. It is based upon second-generation cementation technique and has unacceptably high inter- and intra-observer variability due to its subjective evaluation method.
We are introducing a new grading system of quality of femoral cementation. It is based upon the ratio of the length of radiological lucency to the total length of cement-bone interface on both antero-posterior and lateral views. Because of its objective nature, it is likely to show reproducible results.
We recruited five observers of various grades of surgical experience (trainees to consultant). Each observer graded the quality of femoral cementation on immediate postop xrays twice (gap of atleast two weeks) of 30 primary hip arthroplasties, using Barrack's grading and a new cementation index measured by dividing the ength of Radiolucency along CBI by the total Length of CBI.
Statistical analysis was performed by SPSS v17.0. Inter-observer and Intra-observer variability was determined by Intraclass Correlation Coefficient for a two way mixed model.
New cementation index showed excellent agreement for both inter and intra-observer reliability with intraclass correlation coefficient of 0.79 and 0.82 respectively. On contrary, results of inter-observer reliability for Barrack's grading were poor with value of 0.20. intra-observer reliability was found to be fair with 0.55.
As evident from this study, it is a more reliable way of assessing the quality of cementation, with excellent agreement in both inter and intra-observer categories.
