Increased femoral cartilage thickness in acne patients using isotretinoin: could it be a sign of early osteoarthritis?

Vitamin A derivatives have inhibitory effects on cartilage tissue, such as decreasing chondrocyte proliferation and collagen synthesis, and increasing the loss of glycosaminoglycans and proteoglycans. Therefore, isotretinoin (a vitamin A derivative) may play a role in the pathogenesis of cartilage-related diseases like osteoarthritis by affecting the balance of cartilage tissue. The aim of this study was to evaluate the distal femoral cartilage thickness in acne patients under the systemic isotretinoin therapy and to determine whether it constitutes a risk factor for the development of osteoarthritis. The study included 52 patients (42 female, 10 male, mean age 23.31 ± 3.89 years) who were prescribed systemic isotretinoin for acne and completed at least 3 months of treatment, along with 45 healthy controls ((35 female, 10 male, mean age 23.85 ± 4.77 years). Bilateral distal femoral cartilage thickness was measured by ultrasonography before isotretinoin treatment and after the completion of the third month of treatment. After treatment, a statistically significant increase was found in the thickness of the right medial, right lateral, left medial, left lateral, and left intercondylar cartilage (p = 0.014, 0.012, 0.019, 0.027, 0.002, respectively). There was also an increase in the right intercondylar cartilage thickness, but this was not statistically significant (p = 0.1). Systemic isotretinoin seems to make cartilage thicker. The increase in femoral cartilage thickness observed after short-term isotretinoin treatment might be an indicator of very early-stage osteoarthritis. Extended follow-up studies with larger participant pools are necessary to substantiate this result.