Evaluation of fracture topography and bone quality in periprosthetic femoral fractures: A preliminary radiographic study of consecutive clinical data

The unique configuration of periprosthetic femoral fractures (PFFs) is a major determinant of the subsequent management. The aim of this preliminary study was to investigate potential relationships between fracture angle (FA), fracture level (FL) and bone quality of Vancouver type B PFF. The FA, FL and the canal thickness ratio (CTR) were quantified for 27 patient X-rays. The CTR is an indicator of the underlying bone quality. Relationships between these factors were studied for the whole X-ray set, for a subgroup involving fracture above the tip of the stem and for subgroups with stable and unstable implants. When considering all cases, no significant correlation was found between the FA and any other measurement. Considering only cases with unstable implants, a statistically significant correlation was found between the FA and the FL (R2 = 0.489, p = 0.002). No correlation was found between FA and any other measurement for stable implants suggesting that FA could be considered as an independent factor when classifying B1 fractures. Considering all cases, a weak correlation was found between CTR and FL (R2 = 0.152, p = 0.044) suggesting that fractures below the tip of the stem may indicate a lower bone quality. This preliminary study suggests that the effect of FA on the optimal management of Vancouver type B1 fractures could be considered, independent of the quality of the bone or fracture position. Furthermore, fractures around or below the tip of the stem may suggest a poor bone quality. Larger number of patients is required to confirm these initial findings.