Combination of Microfocused Ultrasound with Visualization and Dilute Calcium Hydroxylapatite Filler for Moderate to Severe Knee Skin Laxity.

Background:Microfocused ultrasound with visualization (MFU-V) and calcium hydroxylapatite (CaHA) filler are modalities for improving skin laxity. Their use in combination on body sites other than the face is expanding.Objective:To investigate the effectiveness and safety of combination MFU-V and dilute CaHA (dCaHA) for lower anterior thigh and knee laxity over 12 and 24 weeks.Methods:Twenty women (40-71 years) with moderate to severe laxity of the anterior thigh and knee were enrolled in this split-body trial. Subjects received dual-depth (3.0mm, 1.5mm) or triple-depth MFU-V (4.5mm, 3.0mm, 1.5mm) to the inferior anterior thigh (127-381 lines) along with dCaHA (1:1 normal saline) injection (0.5-3mL). Clinical effectiveness was monitored using photography, qualitative clinician and subject assessments, and quantitative analysis of skin topography by three-dimensional imaging and dermal thickness by optical coherence tomography.Results:At 12 and 24 weeks, the treated thigh and knee experienced significant improvement in qualitative clinician scales (p<0.01), with subjective improvement on photography and subject-reported assessments; no significant changes were noted by quantitative measures. Adverse events were reported in 68 percent of patients, including mild bruising (n=12) and swelling (n=10).Conclusion:Combining MFU-V and dCaHA is safe and results in clinical improvement of anterior thigh and knee laxity.