Bone stock in revision femoral arthroplasty: a new evaluation.

Purpose: The purpose of this study was to finalize a method allowing a qualitative and numerical evaluation of the bone stock and to confirm its reproducibility, to verify the relationship between the secondary bone stock value and the functional results, and to determine the main factors influencing the value of the bone stock.

Methods: A clinical and radiological evaluation was performed in a group of 150 revisions of total hip replacements according to a new method taking into account cortical bone thickness, bone density and bone defects.

Results: Interobserver reproducibility was evaluated at an average of 0.6 and intra-observer reproducibility was considered good at 0.8. Between the initial bone stock and at the last follow-up, no significant difference was noticed. For secondary bone stock considered as "very good or good", the gain was +38.1 points versus +29.9 points for patients evaluated as "average or poor" (p < 0.0001). Between the initial bone stock assessment and at last follow-up, a significant relation was found in numerical values for the global type of primary fixation and in the presence of osteopenia (p < 0.0001).

Conclusions: Deficient secondary bone stock can result in less favourable functional results. The numerical scores confirm the importance of strategic choices during surgery in order to manage bone stock preservation.