Heterotopic Ossification (HO) is a debilitating disorder of the musculoskeletal system where bone formation abnormally occurs within non-osseous tissues. It has been found to affect two-thirds of the military blast-injury amputees since 2001, making it a “military epidemic”. For amputees, HO represents a severe and painful additional obstacle to their rehabilitation, with no existing satisfactory treatment option. The present work assumes that the HO forming within an amputee’s stump still responds to its loading environment similarly to healthy bone. It thus looks to investigate the interactions between HO and the stump’s loading environment in blast-related military transfemoral amputees, with the overall aim to enable improved clinical treatment through a better understanding of the disease. A previously established adaptive finite element model was utilised and significantly improved upon by fine-tuning the governing bone density adaptation rule. The “saturation effect” was also carefully implemented, a computational translation of the intrinsic physiological limitations of the cellular processes underlying bone remodelling. These modifications made the model more computationally efficient and yielded a more progressive ossification process in the simulation’s early stages, improving its physiological fidelity and bringing it closer to a more complete validation. A sensitivity analysis of the saturation effect’s key parameters further characterised its impact on the model and highlighted how it could be used in other computational bone remodelling studies. From a clinical standpoint, it appeared that the loading orientation on the stump was crucial in determining HO’s development pattern, with different loading regimens causing the formation of different clinically characteristic morphologies of HO. In particular, the model suggested that amputees with an abducted gait are more likely to develop type 2 HO, a more clinically challenging form of the disease, demonstrating how such a descriptive model can help identify at-risk patients and inform the design of prostheses or rehabilitation programs.