Abstract
IntroductionIntercalary endoprosthetic reconstructions have been reserved for patients with a limited life expectancy due to reports of high rates of early mechanical and reconstruction failure.Materials and methodsIn this study, we retrospectively analyzed 28 patients who underwent intercalary endoprosthetic reconstruction of the femur (n = 17) or tibia (n = 11) regarding reconstruction survival and causes of complications and reconstruction failure.ResultsA total of 56 stems were implanted in this collective, 67.9% of which were implanted using cementation. Eight different stem designs were implanted. The mean patient age at the time of operation was 42.3 years. The mean bone defect needing reconstruction measured 18.5 cm. Resection margins were clear in 96.4% of patients. Of twenty-six complications, five were not implant-associated. We observed infection in 10.7% (n = 3) and traumatic periprosthetic fracture in 3.6% (n = 1) of cases. The most frequent complication was aseptic stem loosening (ASL) (53.8%; n = 14) occurring in eight patients (28.6%). The metaphyseal and meta-diaphyseal regions of femur and tibia were most susceptible to ASL with a rate of 39.1% and 31.3% respectively. No ASLs occurred in epiphyseal or diaphyseal location. Overall reconstruction survival was 43.9% and 64.3% including patients who died of disease with their implant intact. Overall limb survival was 72.7%.ConclusionsProper planning of segmental reconstructions including stem design with regard to unique anatomical and biomechanical properties is mandatory to address the high rates of ASL in metaphyseal and metadiaphyseal stem sites. With continued efforts of improving stem design in these implantation sites and decreasing rates of mechanical failure, indications for segmental megaendoprostheses may also extend to younger patients with the localized disease for their advantages of early weight bearing and a lack of donor-site morbidity.
Highlights
Intercalary endoprosthetic reconstructions have been reserved for patients with a limited life expectancy due to reports of high rates of early mechanical and reconstruction failure
Since stem site varies from that of standard stems used for osteoarticular endoprostheses in the diaphysis and different biomechanical conditions apply, different stem properties and designs may be necessary to address higher rates of mechanical failure observed so far
Four patients were treated by a minor superficial debridement and secondary suture, while one patient had to undergo transplantation of a vascularized latissimus muscle flap for a persistent wound healing disorder without the involvement of the reconstruction
Summary
Intercalary endoprosthetic reconstructions have been reserved for patients with a limited life expectancy due to reports of high rates of early mechanical and reconstruction failure. With continued efforts of improving stem design in these implantation sites and decreasing rates of mechanical failure, indications for segmental megaendoprostheses may extend to younger patients with the localized disease for their advantages of early weight bearing and a lack of donor-site morbidity. Biological reconstruction techniques include the use of allografts, (irradiated) autografts, (vascularized) Despite advantages such as early mobility with full weight bearing, joint and growth plate preservation and a lack of donor-site morbidity, indications for the use of segmental megaendoprostheses have been limited to (elderly) patients with metastatic disease and severe pain or instability. Since stem site varies from that of standard stems used for osteoarticular endoprostheses in the diaphysis and different biomechanical conditions apply (i.e. the absence of a joint, which poses an outlet for shear forces, may lead to additional strain on stems in intercalary reconstructions), different stem properties and designs may be necessary to address higher rates of mechanical failure observed so far
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