General Considerations: Analysis of Failure of Fixation: A Stepwise Approach

Fracture fixation failure is in most cases a devastating complication for the patient as it often requires revision surgery, prolongation of the treatment and significant reduction in patient’s quality of live. The overall goal of fracture treatment is to achieve fracture healing and bony consolidation in good alignment and to restore pre-fracture activities. To achieve this goal, surgical implants are required for fracture fixation during the bone healing process to allow the bone to return to its normal and stable biomechanical state. Normal bone healing is fundamentally disrupted and usually even impossible when fixation fails, and the causes appear complex and obscure at first glance. However, a systematic analysis will in most cases identify the underlying cause or even combination of causes for failure. For this, thorough analysis and understanding of the general principles of direct and indirect bone healing is crucial. The “diamond bone concept” covers the three osteoconductive, osteoinductive and osteogenic key elements for bone healing as well as mechanical stability, vascularity and host factors that are pre-conditions for regular bone healing. Equally critical is knowledge of the properties of fixation constructs and surgical implants, both plates and nails. These underlie the process of material fatigue and have a finite number of load cycles until failure. Put another way, implants will only be able to maintain the required stability for bone healing for a certain amount of time. This gives rise to the concept of the “race between bone healing and design failure.” The chapter provides a stepwise approach for analysis of fixation failure, based on general, biological and biomechanical principles and case samples. Therefore, the chapter introduces and focuses the three typical causes for fixation failure: malalignment (I), unstable fixation constructs, and patient’s incompliance.