Radiographic Evaluation of Bone Remodeling Around Osseointegration Implants Among Transfemoral Amputees.

OBJECTIVES

To examine periprosthetic bone remodeling among the recipients of 2 types of lower-limb osseointegrated systems, the Integral Leg Prosthesis (ILP) and the Osseointegration Prosthetic Limb (OPL) type A, over a >24-month period.

DESIGN

Retrospective cohort study.

SETTING

Private hospital, with a specialized osseointegration unit.

PATIENTS

Twenty-eight patients with transfemoral lower-limb amputations were fitted with osseointegrated systems. Of these patients, 15 received the ILP and 13 the OPL osseointegrated implant.

INTERVENTION

Radiographic measurements were taken at baseline (0.4 ± 0.5 years) and at follow-up (3.0 ± 0.8 years) after the osseointegration procedure.

MAIN OUTCOME MEASUREMENTS

Radiographic bone density, longitudinal bone coverage, and bone width outcomes were measured in inverse "Gruen zones." Bone remodeling was evaluated by comparing changes between baseline and follow-up measurements.

RESULTS

Radiographic bone density decreased in all zones among both ILP and OPL groups. Cortical bone thickness increased among the OPL group in zones 3 (P < 0.05) and 5 (P < 0.05). Distal bone coverage of the ILP implant decreased by 2.3% (P < 0.01) and 4.1% (P < 0.05) of the total implant length on the medial and lateral sides, respectively.

CONCLUSIONS

Decreased bone density with increased periprosthetic cortical thickness suggests a change in the bone architecture for the OPL group. The findings of this study raise concerns for the long-term success of the ILP implant. Radiographic analysis of x-rays seems to be a useful tool for clinicians to evaluate bone remodeling around osseointegrated prosthesis.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.