Editorial Commentary: Detailed Assessments of Confounders are Necessary for Valid Interpretations of Patellofemoral...

Cartilage restoration procedures have gained increased traction over the years as a treatment for chondral defects in relatively younger patients. A critical assessment of study populations for confounders is vital to interpret results in a valid manner. This is particularly true when assessing outcomes of cartilage restoration procedures in the patellofemoral compartment because there is often great heterogeneity associated with this population. Patients often undergo additional procedures (prior or concomitant), have variable anatomy (malalignment, maltracking, and trochlear dysplasia), and variable chondral defect sizes, depths, and locations (lateral patellar facet, medial patellar facet, median patellar ridge, trochlea). Without an assessment of study populations for potential confounders that may influence the results, only more limited conclusions can be gleaned from the results pertaining to these procedures. Finally, there are many choices for cartilage restoration (osteochondral autografting, osteochondral allografting, autologous chondrocyte implantation, autologous matrix-induced chondrogenesis, and particulated juvenile articular cartilage) and different clinical situations in which one may confer benefit over the other, yet all seem to result in significant improvement for patients with acceptable failure rates.