Changes in the Biomechanical Gait Characteristics of a Bilateral Prosthesis User After Unilateral Transfemoral Osseointegration: A 2-Year Case Study

ABSTRACT Background Osseointegration (OI) surgery provides a direct connection for the use of bone-anchored prostheses (BAPs), which may reduce gait deviations for unilateral transfemoral prosthesis users. However, there are limited data on individuals with bilateral amputation. Objective This case study reports the gait biomechanics and functional mobility over 2 years for a person with left transfemoral and right transtibial amputation who underwent unilateral transfemoral OI. Study Design This is a longitudinal single-case study with repeated measurements. Methods Spatio-temporal and kinematic parameters from a 31-year-old female patient were recorded by a motion analysis system at baseline (socket prosthesis), and at 6, 12, 18, and 24 months after femoral OI using a BAP. The Questionnaire for Persons with Transfemoral Amputation (Q-TFA) and functional mobility tests were completed at all time points. Results Improvements in cadence and velocity were seen at 18 months after OI, but wide step width persisted. There was improved trunk lean at 12 months but no other time points. Pelvic rotation improved but pelvic tilt and obliquity did not. Hip kinematics were closest to normal at 18 months after OI. The Q-TFA improved (baseline 25.0, follow-up 66.7–83.3). The Timed Up and Go times were 11.0 and 7.9 seconds shorter, and L-Test times 18.5 and 10.1 seconds shorter, at 18 and 24 months after OI, respectively. Conclusions Although patient reported measures improved immediately with using a BAP, biomechanical changes were variable and took longer to improve. Spatio-temporal and kinematic changes at 12 months were less favorable but improved at 18 months after OI, indicating the need for extended recovery and long-term rehabilitation. Further research is needed to validate the results across a larger population. Clinical relevance Improved self-reported function with a BAP was noted immediately; however, functional mobility and biomechanical improvements took longer to improve, indicating that longer follow-up may be needed for complex cases.