AANA Lab Course 910 - Patellofemoral Joint Preservation-Patellofemoral Arthroplasty-Dr. Elizabeth Arendt, M.D.

Patellofemoral Arthroplasty-Dr. Elizabeth Arendt, M.D.

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This presentation by Dr. Elizabeth Arendt, an orthopedic surgery professor at the University of Minnesota, focuses on optimizing patellofemoral arthroplasty (PFA) for isolated patellofemoral osteoarthritis (PF OA).<br /><br />PF OA commonly manifests in lateral, medial, global, or central trochlear groove patterns, often linked with trochlear dysplasia or malalignment. The Iwano classification (1990) grades PF OA severity from remodeling (Grade I) to bone-on-bone involvement (Grade IV). Patients with isolated PF OA, especially with trochlear dysplasia and no significant tibiofemoral joint (TFJ) involvement, are optimal candidates for PFA. Ideal patients are typically aged 40-60 with no focal TF cartilage lesions, minimal malalignment, and sedentary to moderate activity levels.<br /><br />Two main PFA implant types exist: inlay (resurfacing) which preserves trochlear anatomy, and onlay (trochlear cutting) which reshapes the trochlea for better fit and stability. Onlay implants, considered second generation, have shown better survivorship and outcomes compared to inlay designs, which have had higher revision rates. Several FDA-approved onlay prostheses exist in the U.S., including Avon, Vanguard, and Journey systems.<br /><br />Advantages of PFA versus total knee arthroplasty (TKA) include less bone removal, preservation of ligaments, lower surgical morbidity, quicker rehabilitation, and easier revision to TKA if needed. However, progression of tibiofemoral arthritis remains a common failure mode. Technical challenges include achieving proper femoral component alignment, managing patellar thickness and tracking, and accommodating anatomical variations such as patella alta.<br /><br />Dr. Arendt emphasizes understanding different implant strengths and weaknesses to optimize outcomes. Despite a learning curve and imperfect designs, PFA offers a valuable option for select patients with isolated patellofemoral arthritis, yielding significant improvements in pain and function while preserving the rest of the knee joint.

Keywords

patellofemoral arthroplasty

isolated patellofemoral osteoarthritis

trochlear dysplasia

Iwano classification

inlay implant

onlay implant

total knee arthroplasty

patellar tracking

implant survivorship

knee joint preservation