Femoral neck anteversion: measurement, predictors, and effects on musculoskeletal function

Scorcelletti, Matteo (2023) Femoral neck anteversion: measurement, predictors, and effects on musculoskeletal function. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Total femoral torsion and other lower limb geometry parameters show substantial inter-individual variation and contribute to clinical outcomes such as hip dysplasia, hip and knee osteoarthritis, atypical fractures, and disadvantageous kinematics. This thesis aimed to identify appropriate methods to assess femoral torsion. Thereafter, to investigate its determinants and relationship to other aspects of lower limb geometry and muscle function. The literature review identified the clinical importance of femoral torsion, a lack of standardisation in femoral torsion measurement, and the strength and weaknesses of current methods whilst highlighting the need for quick and accurate techniques employable in children. The first study proved the concept of a new three-dimensional biomedical imaging device using a standard ultrasound device, with a linear array probe, coupled with a coordinate-measuring system. This achieved only poor-to-moderate test-retest reliability for femoral torsion (ICC=0.329; CI -0.542-0.843) and femoral length (ICC=0.615; CI -0.071-0.919) respectively but identified a number of potential avenues for improvement of the technique. The second study characterised lower limb geometry in individuals with X-linked hypophosphatemia (XLH) and controls and found large differences in several parameters of lower limb geometry between the two groups. The identification of ~ 18° smaller intertrochanteric rather than shaft torsion in these individuals can inform surgical guidelines. The third study explored the associations of long-term power exercise with lower limb geometry in young and older adults. Only small associations were observed with training and age as effects on femoral bowing in the order of magnitude of ~2°. The ability to alter skeletal geometry through exercise throughout adulthood seems limited, reinforcing the importance of childhood physical activity for lifelong skeletal health. This thesis presented novel insights and methodologies regarding the characterisation of lower limb geometry on three planes and the relationship between the different shape parameters, informing future surgical procedures. It also added new evidence of skeletal shape adaptations to chronic exercise in adulthood and impaired phosphate metabolism.