Patellofemoral arthroplasty in patients with arthritis

For more than a decade, good to excellent results have been obtained in patients with patellofemoral arthritis (PFA) who have undergone total knee arthroplasty (TKA) to relieve debilitating pain and impaired mobility. Still, there is controversy over the optimal surgical management of these patients. The central question persists: Is TKA more than is needed to restore pain-free mobility — especially in young, active patients?

A new approach

The vast majority of patellofemoral pain and early patellofemoral arthritis can and should be treated nonoperatively. But cautious consideration of a new approach, patellofemoral arthroplasty (PFA), may be indicated in carefully selected refractory cases of advanced degenerative disease confined to the patellofemoral articulation.

Patients with patellofemoral arthritis may not have disease in all three knee compartments. This finding has led a few centers — Mayo Clinic among them — to adapt partial knee arthroplasty approaches more commonly used in lateral and medial compartment procedures to cases involving only the patellofemoral articulation. Although the study of the technique is ongoing, Mayo surgeons have performed more than 100 procedures and are encouraged by the early results. Selecting the appropriate patient is paramount to achieving the goal of excellent outcomes associated with TKA, but through a less invasive surgical procedure.

Benefits and risks

Compared with TKA, partial, or unicompartmental, arthroplasty management of isolated patellofemoral arthritis offers potential benefits of:

  • Sparing the remaining healthy knee compartments and associated structures
  • Inflicting less surgical trauma and blood loss
  • Minimizing risk of complications
  • Reducing hospital stay
  • Supporting an easier overall recovery and return to lifestyle
  • Possibly serving as a bridging treatment for active younger patients who may one day be candidates for TKA

Risks include mid- to long-term failure as a result of tibiofemoral degeneration, which has been reported to occur in up to 25 percent of patients and is the subject of a new Mayo Clinic study.

Identifying the ideal patient for PFA

Patient selection is central to the success of treating patellofemoral arthritis with the partial procedure. Patellofemoral pain is multifactorial and complex in terms of symptomatology, and patients may be motivated by their discomfort and disability to assume the solution is surgical. But it is imperative to exhaust all nonoperative measures first. Surgery is not indicated for mild cases that upon radiographic, MRI or arthroscopic exam lack severe degeneration of the patellofemoral articulation.

Patient selection criteria

Indications:

  • Advanced, isolated primary PFA
  • PFA with trochlear dysplasia, often with a history of instability
  • Post-traumatic PFA

Contraindications:

  • Moderate or advanced tibiofemoral chondromalacia
  • Severe malalignment and maltracking
  • Inflammatory arthritis, morbid obesity, patella baja

In addition to fulfilling indication criteria, the ideal patient also has the following features:

  • Minimal pain while walking on level surfaces
  • Isolated anterior retropatellar pain that is exacerbated by:
    • Standing from seated position
    • Climbing up and down stairs
    • Walking on uneven surfaces
    • Sitting long periods with knee flexed

For more information

Patellofemoral arthroplasty in arthritis patients. Orthopedic Update. 2012;6:1.

Points to remember

  • The vast majority of patellofemoral pain and early patellofemoral arthritis can and should be treated nonoperatively.
  • A new approach, patellofemoral arthroplasty (PFA), however, may be indicated in carefully selected refractory cases of advanced degenerative disease confined to the patellofemoral articulation.
  • Patient selection is central to the success of treating patellofemoral arthritis with PFA.