What signifies the beginning of ankylosis in biomechanical changes?

Ankylosis refers to the fusion of bones or the stiffening of a joint due to pathological processes, and its onset is primarily associated with advanced stages of biomechanical changes in the joint. Phase 3 conditions are indicative of significant joint degeneration, where there is a notable decrease in range of motion, the presence of osteophytes, and changes in the joint surfaces. This phase represents the progression toward irreversible damage, which is characterized by the potential fusion of bones, leading to ankylosis.

This understanding aligns with the concept that during Phase 3, physiological changes are sufficient to cause not only substantial mechanical dysfunction but also a shift toward a pathological state, where the body's adaptive responses may lead to ankylosis as a final outcome of chronic stress on the joint and surrounding tissues. Thus, the recognition of Phase 3 conditions is crucial for identifying when such advanced degeneration and joint stiffness begins to manifest.