Feasibility study on the potential of a spiral blade in osteoporotic distal femur fracture fixation

• Published in: Archives of orthopaedic and trauma surgery Vol. 133; no. 12; pp. 1675 - 1679
• Main Authors: Wähnert, D., Hofmann-Fliri, L., Götzen, M., Kösters, C., Windolf, M., Raschke, M. J.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2013; Springer Nature B.V
• Subjects: Amputation; Biomechanical Phenomena; Feasibility Studies; Femoral Fractures - physiopathology; Femoral Fractures - surgery; Fracture Fixation, Internal - instrumentation; Fractures; Humans; Knee; Medicine; Medicine & Public Health; Orthopedics; Osteoporotic Fractures - physiopathology; Osteoporotic Fractures - surgery; Trauma Surgery; Osteoporosis; Distal femur; Spiral blade; Osteoporotic fracture
• ISSN: 0936-8051; 1434-3916
• DOI: 10.1007/s00402-013-1862-y

Introduction Osteoporotic fractures of the distal femur (primary as well as periprosthetic) are a growing problem in today’s trauma and orthopaedic surgery. Therefore, this feasibility study should identify the biomechanical potential of a (commercially available) spiral blade in the distal femur as compared to a single screw without any additional plate fixation. Additionally, the influence of cement augmentation was investigated. Materials and methods An artificial low density bone model was either instrumented with a perforated spiral blade or a 5 mm locking screw only. Additionally, the influence of 1 ml cement augmentation was investigated. All specimens were tested with static pull-out and cyclic loading (50 to 250 N with an increment of 0.1 N/cycle). Results In the non-augmented groups, the mean pull-out force was significantly higher for the blade fixation ( p  < 0.001). In the augmented groups, the difference was statistically not significant ( p  = 0.217). Augmentation could increase pull-out force significantly by 72 % for the blade and 156 % for the screw, respectively ( p  = 0.001). The mean number of cycles to failure in the non-augmented groups was 12,433 (SD 465) for the blade and 2,949 (SD 215) for the screw, respectively ( p  < 0.001). In the augmented group, the blade reached 13,967 (SD 1,407) cycles until failure and the screw reached 4,413 (SD 1,598), respectively ( p  < 0.001). Conclusion The investigated spiral blade was mechanically superior, significantly, as compared to a screw in the distal femur. These results back up the further development of a distal femoral blade with spiral blade fixation for the treatment of osteoporotic distal femur fractures.