A Randomized, Split-Body, Placebo-Controlled Trial to Evaluate the Efficacy and Safety of Poly-l-lactic Acid for the Treatment of Upper Knee Skin Laxity

BACKGROUND Skin laxity of the upper knee and lower thigh is a common complaint among patients. OBJECTIVE This is a randomized, double-blinded, split-body, placebo-controlled study to evaluate the safety and efficacy of poly- l -lactic acid (PLLA) for treatment of upper knee skin laxity. MATERIALS AND METHODS Twenty female subjects between the ages of 30 and 65 years with upper knee laxity were enrolled. The patients were randomized to receive 3 treatments of PLLA in 1 knee, whereas the other knee received 3 treatments of bacteriostatic water. RESULTS Statistically significant improvement as rated on the physician global aesthetic improvement scale was seen at Day 56 after final treatment in the active knee when compared with the placebo knee. This improvement was sustained at Day 84 and Day 168 after final treatment visits. No statistically significant difference was seen between the active and placebo knees on the subject global aesthetic score or the subject satisfaction scale. CONCLUSION Based on our study, PLLA may be a safe and effective modality in addressing upper knee skin laxity. Larger studies with longer follow-up times and a validated knee laxity scale are needed to further determine if and how much improvement can be achieved.