Patellar Bone Loss

Patellar Bone Loss

Kevin I. Perry

Arlen D. Hanssen

Key Concepts

  • 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).

  • Most important concept: None of these patellar reconstructive procedures should be performed as an isolated procedure if the femoral or tibial components are not in proper rotational position.

Sterile Instruments and Implants

  • Typical setup for revision TKA if tibial or femoral revision required

  • High-speed burr

  • Nonabsorbable #1 sutures

Surgical Approaches

  • Standard medial parapatellar arthrotomy

Preoperative Planning

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

Bone, Implant, and Soft Tissue Techniques

  • 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.

    Figure 72.1 ▪ Intraoperative photograph demonstrating a thin patellar shell with fibrous tissue on the undersurface of the patellar tendon.

    Figure 72.2 ▪ Intraoperative photograph demonstrating fibrous tissue around the patellar rim and on the undersurface of the quadriceps tendon.

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    Dec 14, 2019 | Posted by in ORTHOPEDIC | Comments Off on Patellar Bone Loss
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