Introduction: Amputees may be eligible to use a socket or osseointegrated (OI) prosthesis after losing a limb. A lot is known about the stump-socket interface in transtibial (TT) amputees. However, there are hardly any articles that explain the load transfers between the tibia and an OI prosthesis. For this reason, this study will focus on the load pattern at the bone-implant interface. The aim is to investigate how the osseointegrated loading for TT amputees is compared to able-bodied subjects. Method: Two generic musculoskeletal models were created in OpenSim: a transtibial osseointegrated (TTO) model and an able-bodied model. The able-bodied model includes all muscles in the lower limb, where the TTO model had no muscles around the tibia. Two datasets, consisting of five able-bodied participants (healthy control (HC)) and five transtibial amputees (TTA) with a socket prosthesis, were used. The internal reaction forces and moments were analysed for the affected side during the stance phase of the gait cycle. These normalized forces and moments were expressed in bodyweight (BW) and bodyweight x height (BWH), respectively. Results: The largest forces at the bone-implant interface were measured in the longitudinal direction (-6.92 BW) for the able-bodied model, the lowest in the mediolateral direction (-0.09 BW) for the TTO model. The loading differences were the highest between the able-bodied model and the TTO model with TTA data. Around the antero-posterior axis, the largest moments were found. The able-bodied model measured 0.027 BWH, where the TTO model with HC data found 0.023 BWH and 0.017 BWH for the TTA data. Conclusion: Transtibial amputees have decreased loading at the bone-implant interface compared to able-bodied subjects. The muscles play the most prominent role in comparison with the gait pattern.