Background: Osteonecrosis of the distal portion of the femur
produces a segment of dead bone in the weight-bearing portion of the femoral
condyle, frequently associated with subchondral fracture and collapse and
eventually resulting in secondary osteoarthritis. Treatment of these late
stages of osteonecrosis in the knee can be problematic. The purpose of the
present study was to evaluate a new surgical technique in which the
subchondral osteonecrotic lesion is removed. The bone defect is then
reconstructed with impacted bone grafts to prevent collapse and/or to regain
distal femoral sphericity.
Methods: In this prospective, one-surgeon study, nine consecutive
knees in six patients were studied, all of which had extensive
corticosteroid-associated osteonecrotic lesions of the femoral condyles. Six
knees had collapsed lesions when they were initially treated. The mean age of
the patients was thirty-one years. Both the clinical and radiographic outcomes
were assessed at a minimal follow-up time of two years.
Results: At a mean follow-up time of fifty-one months, none of the
reconstructed knees had been converted to a total knee prosthesis. The
objective Knee Society score improved from a mean of 63 to 89 points. The
functional Knee Society score improved from a mean of 19 to 81 points. During
the follow-up period, there was no progression of collapse observed; however,
three knees showed early signs of osteoarthritis. Clinical success was
achieved in six of eight knees, and radiographic success was achieved in seven
of nine knees.
Conclusions: At the time of writing (at the time of midterm
follow-up), this method appears attractive as a joint-preserving procedure. It
is a relatively simple procedure that is not likely to interfere with future
knee procedures. It appears that this technique can be effective in knees with
collapse of the femoral condyle, and it may delay the need for a total knee
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors on
jbjs.org for a
complete description of levels of evidence.