Objective: This study investigated microstructural changes of the right and left midshaft femur in an archaeological individual afflicted with left-sided hip joint ankylosis to assess whether increased cortical porosity was present as a result of leg disuse.
Materials: The individual is a middle-aged adult male excavated from the Metal Period (∼2000 BP) Nagsabaran, Luzon Island, Philippines.
Methods: Following standard examination of femur gross anatomy and differential diagnosis of the hip joint fusion, ∼1 cm thick posterior midshaft femur samples were removed for microstructural examination. Using static histomorphometry, bone multi-cellular unit activity from Haversian canal (vascular pore) density, area, and circularity was reconstructed. Spatial positioning of Haversian canals was mapped using Geographic Information Systems software. Phosphate, carbonate, and carbonate:phosphate ratios were obtained using synchrotron-sourced Fourier transform infrared microspectroscopy.
Results: The left femur had greater cortical pore density, with smaller and rounder vascular canals, in addition to lower matrix levels of phosphate and carbonate, when compared to the right femur.
Conclusions: Our data indicate compromised bone tissue in the left femur, and conform to expected bone functional adaptation paradigms of remodeling responses to pathological and biomechanical changes.
Significance: The preservation of this individual's hip abnormality created a unique opportunity to evaluate intra-skeletal bone health asymmetry, which may help other researchers evaluate the presence of limb disuse in archaeological samples.
Limitations: A lack of lower limb data limits our interpretations to femur remodeling only.
Suggestions for Further Research: Future research efforts should aim to examine the presence of remodeling changes in all bones of the lower limb.
- Joint stiffness