The majority of patellar revisions are performed with standard or biconvex patellar components. Less than 10% of revision total knee arthroplasty (TKA) are associated with severe patellar bone deficiency requiring one of several alternative reconstructive techniques.

Severe patellar bone loss, leaving the so-called patellar shell (Figure 72.1), can be managed by simple patellar resection arthroplasty, a gull-wing osteotomy, use of a dedicated porous metal-polyethylene revision construct, or cancellous impaction bone grafting (preferred and described here).

Typical setup for revision TKA if tibial or femoral revision required

High-speed burr

Nonabsorbable #1 sutures

Standard medial parapatellar arthrotomy

Determine if only partial femoral or tibial component revision will be required and have proper implants available.

For severe patellar bone loss, we prefer the patellar bone grafting technique. After performing arthrotomy, leave all peripatellar tissue intact. This includes the thick fibrous rind on the undersurface of quadriceps tendon as this tissue is necessary to create the tissue pouch to contain the cancellous bone graft (Figure 72.2).

The loose or failed patellar implant is carefully removed to minimize additional bone loss.

Ensure that tibial and femoral components are rotated properly so that central patellar tracking can be achieved, otherwise patellar reconstruction failure is likely.

If femoral revision is required, it is often possible to harvest enough cancellous bone in the central portion of the femur during revision of cruciate retaining implants. Additional cancellous bone can also be obtained from the metaphyseal/diaphyseal junction when preparing the femoral canal for a stemmed revision implant.