Background: Severe patellar bone loss may preclude
adequate fixation of another patellar prosthesis as a part of revision
knee replacement. The purpose of this study was to describe the
surgical technique and early clinical results of an alternative
to the conventional treatment options of either patellectomy or retention
of the remaining patellar osseous shell. The goals of this procedure
are to restore patellar bone stock and potentially to improve the
Methods: Severe patellar bone loss had left a "patellar
shell" that precluded insertion of another patellar implant in nine
of 100 consecutive knees undergoing revision total knee arthroplasty.
Rather than performing a patellectomy or simply retaining the patellar osseous
shell in these nine knees (eight patients), I performed a surgical
procedure in which a tissue flap was secured to the patellar rim
to contain cancellous bone graft inserted into the patellar bone defect.
Final follow-up was at a mean of 36.7 months (range, twenty-four
to fifty-five months) after the patellar bone-grafting procedure.
Results: The mean preoperative Knee Society scores
for function and pain were 39 points (range, 18 to 82 points) and
40 points (range, 20 to 80 points), respectively. At the time of
final follow-up, the Knee Society function and pain scores had improved
significantly, to a mean function score of 91 points (range, 80
to 98 points) and a mean pain score of 84 points (range, 65 to 100
points) (p < 0.05). The point of greatest patellar thickness
measured intraoperatively ranged from 7 to 9 mm. Patellar thickness
on immediate postoperative Merchant radiographs averaged 22 mm (range,
20 to 25 mm) whereas, at the time of final follow-up, patellar thickness
averaged 19.7 mm (range, 17 to 22.5 mm).
Conclusions: In contrast with other treatment alternatives,
this surgical procedure imparts the potential for restoring patellar
bone stock and may improve functional outcome by facilitating patellar
tracking and improving quadriceps leverage. On the basis of satisfactory
short-term to mid-term clinical results, this technique of patellar
bone-grafting appears to be an important addition to the armamentarium
of surgeons performing revision knee arthroplasties.