Customized blade plate effective for periprosthetic supracondylar femur fractures

One patient had bony union and 90° movement with no pain, complications or malalignment at three months postop.

A customized, slotted blade plate is a viable alternative to several treatments for periprosthetic supracondylar femoral fractures following total knee replacement. In a recent study, surgeons used the device in lieu of casting, intramedullary nailing and revision arthroplasty.

“Management of periprosthetic femoral fractures after TKR remains a challenge,” said Shanmugam Karthikeyan, MRCS, an orthopedic surgeon and author of the study. He presented study results at the British Orthopaedic Association Annual Congress. He and co-authors D.T. Wainwright and S.J. Krikler practice at Warwick Medical School, University Hospitals of Coventry and Warwickshire, England.

Causes, risks and device choice

Periprosthetic femoral fractures are uncommon after total knee replacement, occurring after only 0.3% to 2.5% of operations, but are expected to increase. Such fractures occur most often in women over 60 years of age, usually within 15 cm of the joint line. Causes include low-impact falls. Risks include osteoporosis, rheumatoid arthritis, steroid therapy, neurological disorders, anterior cortical notching and revision knee arthroplasty, Karthikeyan said.

Surgeons chose the slotted blade plate partly because it offers good distal fixation.

“[Dynamic condylar screws] and 95° angled blade plates have been used in the past with variable results,” Karthikeyan said. “As the lag screw or the blade has to be inserted more proximally to avoid the femoral component, the distal fixation is often suboptimal, leading to malunion.” Also, conventional open reduction and internal fixation was impossible because of a small distal fragment, he said.

The preferred device has a slot cut into the blade, a 12 mm space in the middle and two prongs passing around anchor pegs in the femoral component. It may be placed distally, providing optimal fixation, “especially where the distal fragment is very small with a well-fixed prosthesis,” Karthikeyan said.

Techniques and desired results

Desired goals included achieving bony union in less than six months, 0° to 90° of motion, elimination of knee pain and return to pre-fracture mobility, Karthikeyan said.

He focused on one patient who received a customized slotted plate: a 62-year-old woman who had TKR four years earlier and had fallen on her knee. The patient’s comorbidities included hypertension and hypothyroid disease, breast cancer and depression.

Surgeons laterally exposed the distal femur, marked articular surfaces with K wires and inserted a K wire into the space between the prosthesis and the anchor pegs. They then drilled transverse holes on both sides of the pegs, using the K wire as a guide.

The patient wore a hinged knee brace for six weeks after surgery. The operated knee bore no weight for six weeks, partial weight for another six weeks and full weight after a 12-week radiographic check.

The results met expectations. At three months, the patient had no knee pain, knee movement of 0° to 90° and no complications. Radiographs showed satisfactory union and no malalignment evidence.

Karthikeyan strongly recommended considering the slotted blade plate as an alternative option in treating displaced supracondylar periprosthetic fractures.

For more information:
Karthikeyan S, Wainwright DT, Krikler SJ. Customised blade plate for supracondylar fracture of femur above total knee replacement. Presented at the British Orthopaedic Association Annual Congress. Sept. 20-23, 2005. Birmingham, England.