Osseointegrated total knee replacement connected to a lower limb prosthesis: 4 cases.

BACKGROUND AND PURPOSE Osseointegrated implants are an alternative for prosthetic attachment in individuals with amputation who are unable to wear a socket. However, the load transmitted through the osseointegrated fixation to the residual tibia and knee joint can be unbearable for those with transtibial amputation and knee arthritis. We report on the feasibility of combining total knee replacement (TKR) with an osseointegrated implant for prosthetic attachment. PATIENTS AND METHODS We retrospectively reviewed all 4 cases (aged 38-77 years) of transtibial amputations managed with osseointegration and TKR in 2012-2014. The below-the-knee prosthesis was connected to the tibial base plate of a TKR, enabling the tibial residuum and knee joint to act as weight-sharing structures. A 2-stage procedure involved connecting a standard hinged TKR to custom-made implants and creation of a skin-implant interface. Clinical outcomes were assessed at baseline and after 1-3 years of follow-up using standard measures of health-related quality of life, ambulation, and activity level including the questionnaire for transfemoral amputees (Q-TFA) and the 6-minute walk test. RESULTS There were no major complications, and there was 1 case of superficial infection. All patients showed improved clinical outcomes, with a Q-TFA improvement range of 29-52 and a 6-minute walk test improvement range of 37-84 meters. INTERPRETATION It is possible to combine TKR with osseointegrated implants.