RELIABILITY OF RADIOGRAPHIC CLASSIFICATION OF FEMORAL BONE DEFICIENCY AT REVISION TOTAL HIP REPLACEMENT

Abstract

Introduction and Aims: To aid the comparison of results of different techniques of femoral revision at total hip replacement and in choosing types of revision, a number of radiographic classifications have been proposed. We aimed to determine the reliability of five popular radiographic classification systems for grading the extent of femoral bone deficiency.

Method: Twenty pre-revision total hip replacement femoral radiographs were assessed by a senior consultant specialist in revision surgery, a junior consultant, a fellow and a trainee registrar. The femoral bone deficiency was classified using the systems of the American Academy of Orthopaedic Surgeons (AAOS) and EndoKlinik, and those described by Paprosky, Gross and Gustillo. Intra-observer agreement and inter-observer agreement between assessors were determined using the kappa coefficient. Radiographs were reassessed after a minimum of two weeks. Kappa coefficients of 0.6–0.8 (substantial) or > 0.8 (almost perfect) were considered to indicate acceptable agreement. Intra-operative measurement of deficiency was also undertaken.

Results: Intra-oberser agreement was rated as acceptable for the Paprosky, Gross and Gustillo systems, each giving substantial agreement, but was unacceptable for the AAOS and EndoKlinik systems. Inter-observer agreement was unacceptable for all systems except the Gross classification system, which was rated as having substantial agreement.

Conclusion: Comparing results of femoral revision between different surgeons based on bone deficiency according to the most popular radiographic classification systems is doubtful because of poor reliability. These classifications can be used by an individual surgeon as a guide to management, but most classifications should not be used to recommend the type of femoral revision to other surgeons.