50% reduction of pain was reported in about 1/2 of post shoulder and knee arthroplasty pain cases with Botox injections. This was sustained by repeated injections.
Br J Med Med Res. 2014 Jan;4(1).
Efficacy of Long-term Effect and Repeat Intraarticular Botulinum toxin in Patients with Painful Total Joint Arthroplasty: A Retrospective Study.
(can download article from there)
- moderate to severe refractory prosthetic joint pain
- ruled out implant infection, loosening or any surgically explainable cause of pain
- used 100 – 300 u Botox in 5 mls saline
- Confirmed joint penetration by ability to aspirate joint fluid
- average 3 shots
- if failed at 100 units worked up to 200-300
- average 3 injections over average 1 year followup.
- at 3 -4 months after injection, 57% patients reported 50% reduction in daytime pain
Comment – that, combine with work on retinaculum and muscles, should deal with post knee issues. Have not seen failed shoulder arthropjasty recently.