LARGE RESECTION PROSTHESES

The development of new large resection prostheses has created major opportunities for orthopaedic oncological surgeons to replace skeletal segments such as the long bones of the upper and lower limbs and related joints. Prof. Calori's experience in the treatment of non-unions, severe bone loss and complex prosthetic revisions has led him, at times, to be faced with the reality of failure a few times after unsuccessful attempts at reconstruction.

When faced with certain drastic radiological and/or clinical situations, oncological surgery principles are applied with large prosthetic replacement solutions. Large resection prostheses are implanted using either 1 or 2 stage techniques depending upon the patient's septic condition in trauma sequelae and complex revisions.

LARGE RESECTION PROSTHESIS DUE TO TRAUMA SEQUELAE

In carefully selected patients, in whom regeneration is no longer viable because of the limited chance of success because the general and local conditions of the patient have elapsed, prosthesis operations can still be performed.

These include the removal of the entire pathological part and the implant of large resection prostheses. These surgical treatments are able to restore autonomy to the patient and function to the affected limb.

FIG.16

Young woman affected by severe non-union of the distal femur with extensive bone necrosis and numerous previous unsuccessful surgeries.

The patient was treated through complete removal of the lesion and the implant of a large resection prosthesis of the distal femur.

FIG.17

Patient affected by severe bifocal bone loss of the femur with axial and rotational deformity and associated severe shortening. The medical history showed severe refractory osteomyelitis to the antibiotic therapy.

The patient walked with aids for about 3 years and wore an external fixation device for 18 months without healing.The soft tissue conditions were meagre.

After ineffective salvaging attempts and tissue debridement with antibiotic cement, the patient underwent total replacement of the femur with large resection arthroprothesis assembled and coated with silver for antibacterial purposes.

The patient now walks with good hip joint and knee function and without pain.

LARGE RESECTION PROSTHESES IN COMPLEX REVISIONS

Periprosthetic bone defects are great challenges for the orthopaedic surgeon. We can distinguish between three different situations in which a periprosthetic bone loss can occur and in which it is possible to implant large resection prostheses or megaprostheses:

The first situation is aseptic mobilization of the prosthetic components due to mechanical failure of the implant, often a large amount of wear of the components and secondary osteolysis are present. When the bone defect is large enough to contraindicate a standard prosthesis revision, a megaprosthesis implant could be one solution.

FIG.18

Patient affected with severe loss of periprosthetic bone, in part replaced with cement in the trochanteric region. The first two images are pre-operative x-rays that show the mobilization and major shortening of the lower limb.

The surgical treatment consisted of the complete removal of the femoral prosthetic component (maintaining the acetabular component) and remaining necrotic bone tissue and implant of a megaprosthesis of the proximal femur as shown in the two x-rays to the right.

The second situation is a septic complication after a prosthesis that leads to critical bone loss.

The defect is usually connected to a serious local inflammatory reaction and bone necrosis.

In this case, a two stage procedure (1st stage: resection, cleaning and implant of an antibiotic spacer, 2nd stage: removal of the spacer and implant of a megaprosthesis) seems to be the best and safest choice in order to restore function, improve the patient's quality of life and avoid septicaemia.

FIG.19

Patient suffering severe periprosthetic bone loss following a fracture of the left femur treating with cerclage and complicated by now chronic osteomyelitis.

The first image (CT) shows the bone loss. Upon removal of the prosthesis (second image) the situation is characterized by complete mobilization and a framework of sepsis with bone necrosis.

The prosthesis is removed, following by an in-depth debridement of the soft tissue and implant with antibiotic spacer that is left in place for about 2 months (third image).

Upon removal, with sterilization of the segment achieved, it is possible to implant a definitive, large resection prosthesis as shown intra-operatively in the fourth image and by x-ray in the last image.

The third situation is the periprosthetic fracture or its complication of the periprosthetic non-union.

These cases are characterized by low bone quality (osteoporosis) and/or severe periprosthetic bone loss with mobilization of the stem and/or acetabular component. If performing an osteosynthesis is not possible or safe, implanting a megaprosthesis could resolve both the fracture/non-union and the prosthetic mobilization.

FIG.20

Patient affected by periprosthetic fracture of the left femur.

The bone quality (severe osteoporosis) does not offer a guarantee of success in the case of osteosynthesis. Complete mobilization of the stem and severe bone loss is seen intra-operatively.

Through reinforcements with metal cerclages, a large resection prosthesis of the proximal femur is implanted.

This solution can restore function to the affected limb in a short period of time with quick mobilization of the patient and good functional recovery.