Evidence of trauma in a ca. 1-million-year-old patella of Homo antecessor, Gran Dolina-Atapuerca (Spain)

We present the palaeopathological study of a left patella (ATD6-56) belonging to the Early Pleistocene species Homo antecessor (Atapuerca-Gran Dolina, Spain). The abnormal morphology observed in the inferior margin of the patella is an osseous overgrowth (osteophyte). Macroscopic and microscopic techniques, including microtomography and zoom stereomicroscope, were used to describe the lesion. Externally, the osteophyte has a smooth and porous texture; the boundary between the more radiolucent osteophyte and the normal bone can be identified in X-ray images. We suggest that the observed signs could be secondary to a local trauma. The lesion would have involved either the bone or related soft tissues of the left limb, possibly affecting the stability of the joint. Consequently, the individual's knee would have suffered an abnormal mechanical load that could have eventually triggered osteoarthritic changes. This is also supported by the lack of changes observed in the associated right patella (ATD6-22).