Case presentation and investigation
Our patient was a 46-year-old male who initially presented to our
orthopedic oncological department at 16 years of age with pain in the
lower left limb associated with a growing mass and swelling of the knee.
Radiological examination revealed a permeative, mixed lytic, and
osteoid-forming lesion arising from the metaphysis of the left distal
femur. Initial suspicions were bone primary sarcoma or osteomyelitis.
The biopsy confirmed the diagnosis of conventional intramedullary
high-grade osteosarcoma of the left distal femur. Staging investigations
ruled out systemic metastatic disease and skip metastases with a
resectable bone tumor.
We decided to perform a wide resection of the distal femur and a
reconstruction with an osteochondral femoral allograft. One year later,
he developed a peri-implant infection requiring 2-stage revision,
initially placing an antibiotic spacer with an intramedullary nail for
ten months. Then, we performed a reconstruction with another distal
femoral osteochondral allograft. Twelve years after the initial
procedure, he underwent conversion to knee oncological endoprosthesis
due to a distal metadiaphyseal fracture of the femoral allograft. He
developed a late periprosthetic infection eighteen years after
endoprosthesis implantation. He was initially treated with several
surgical debridements and suppressive antibiotics with the intention of
implant retention (FigureĀ 1 ).
The x-rays and computational tomography (CT) analysis revealed severe
bone loss in the middle femur and septic loosening in the tibial
component.
After extensive discussions with the patient, ablative surgery was
indicated and opted for due to continuous drainage, non-healing sinus
tracts, significant limb length discrepancy, severe joint stiffness, and
non-controlled pain. Van Nes rotantioplasty was not considered because
of the rigid equinus deformity secondary to limb length discrepancy.
We performed tibial turn-up plasty thirty years after the initial
intervention. The goal was to provide additional osseous length and
optimize prosthesis fitting, avoiding extremely short transfemoral
stump.