Enduring efficacy of Botulinum toxin type A injection for refractory anterior knee pain.

Purpose: To examine long-term outcomes of Botulinum toxin type A (BoNT-A) injection to vastus lateralis (VL) for refractory anterior knee pain (AKP).

Methods: Two cohorts (private clinic referrals and previous research participants) injected with BoNT-A for AKP by one neurologist were surveyed retrospectively. Primary outcomes were self-reported benefit, duration of symptom relief, and knee surgery post-injection.