Arthroplasty vs. joint preservation in young adults
Treatment of full-thickness patellofemoral chondral lesions in young patients remains a challenge. The goal of restoring hyaline cartilage that possesses normal structural and mechanical properties has been particularly difficult to achieve in the patellofemoral joint. Treatment options include marrow stimulation techniques, osteochondral autograft or allograft transfer and various autologous chondrocyte implantation (ACI) techniques. Concomitant correction of anatomic abnormalities, such as tibiofemoral or patellofemoral malalignment, appears to improve the results of such restoration procedures.
Noyes and colleagues recently performed a systematic review in an attempt to determine the ideal operation for treatment of large, symptomatic articular cartilage lesions of the patellofemoral joint in patients less than 50 years of age. Eighteen studies were included, and the procedures performed included ACI, osteochondral allograft transfer (OAT) and patellofemoral arthroplasty (PFA). They concluded that all three procedures had unpredictable results, with the percentage of patients who failed to receive benefit averaging 22% after PFA, 53% after OAT and between 8% and 60% following ACI. It should be noted that the vast majority of included studies were level IV, and none had a control group. Additionally, only two studies reported long-term (more than 10 years) follow-up.
Diane L. Dahm
In light of this data, how does one decide on treatment for such patients? It is my preference to treat younger patients (less than 40 years old) more aggressively with respect to joint preservation, particularly in the setting of unipolar lesions with circumferential surrounding cartilage. Significant patellofemoral and tibiofemoral malalignment are typically corrected along with an attempt at cartilage restoration. In cases of bipolar, lateral patellofemoral lesions, a facetectomy is considered. In this young patient population, PFA is reserved as a salvage procedure after failure of attempted joint preservation in the setting of advanced, diffuse patellofemoral arthritis.
Patients older than 40 years old are treated on an individual basis, with a lower threshold for proceeding to PFA, particularly in the setting of bipolar disease. Contraindications to PFA include inflammatory arthritis, significant tibiofemoral malalignment and moderate to advanced tibiofemoral chondromalacia. Morbid obesity, early tibiofemoral chondromalacia with marginal osteophyte formation and patella baja are considered relative contraindications. Patients with trochlear dysplasia may be particularly suited for PFA, given the propensity of these patients to develop isolated patellofemoral arthritis with relatively low rates of progression of tibiofemoral arthritis over time.
A flow chart summarizing the options and indications for the treatment of patellofemoral cartilage lesions and arthritis can be found online at www.patellofemoral.org/pfoe/PDFs/PPain/Dahm_Joint_Preservation.pdf.
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