- one should consider not resurfacing the patella if less than 12mm of native bone remains (fx or early loosening may result);
- obviously, if sepsis is present then patellar component removal is required;
- if patellar component is to be retained, then it is necessary to surgically remove the peripatellar "meniscal" tissue that typically grows around patellar component;
- subsequently ensure that there is no patellar loosening;
- finally if the patellar component is to be retained, there should be good compatibility with the revision femoral component;
- some suggest sewing a remnant of the patellar fat pad into the patella if it is not resurfaceable;
- revision patellas are thicker to make up for lost bone and have shorter pegs;
- if a primary patellar component is having its peg shortened for use in a revision situation, cut the peg with an oscillating saw away from the wound to prevent a shower of polyethylene particles;
- following revision, the patellar height should be around 24-26 mm;
- in the report by Hanssen AD
, the author describes 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;
- goals of this procedure were to restore patellar bone stock and potentially to improve the functional outcome;
- surgical procedure involves creating a tissue flap secured to patellar rim to contain cancellous bone graft inserted into 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;
- mean preop 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).
- 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).
- ref: Bone-Grafting for Severe Patellar Bone Loss During Revision Knee Arthroplasty
- Secondary resurfacing of the patella for persistent anterior knee pain after primary knee arthroplasty.
- Fate of the unrevised all-polyethylene patellar component in revision total knee arthroplasty.
- Isolated revision of the patellar component in total knee arthroplasty.
- Revision of failed patellar components.
- Patellar component resection in revision and reimplantation total knee arthroplasty.
- The Effect of Stuffing the Patellofemoral Compartment on the Outcome of Total Knee Arthroplasty
Original Text by Clifford R. Wheeless, III, MD.