Method Fifty patients were assigned at random to receive intra-articular shoulder injection. The treatment groups were divided into two groups: BoNT-A group, 200 IU of BoNT-A and 2 ml of normal saline; triamcinolone acetonide (TA) group, 20 mg of triamcinolone and 2 ml of 2% lidocaine. Uptake ratio of quantitative three phase bone scintigraphy (QTPBS) was calculated by dividing the radioactivity count on the affected side by that on the unaffected side. Shoulder pain was assessed by visual analogue scale (VAS) and neuropathic pain scale (NPS). Range of motion (ROM) of shoulder joint and functional independence measurement (FIM) of upper limb were evaluated. All of them were measured before injection, and 4 weeks after injection.

Results
After 4 weeks, the uptake ratio of blood pool phase was significantly decreased in hands of BoNT-A group than TA group. VAS, ROM and upper extremity FIM was similarly improved in both groups. Pain intensity and cold pain of NPS were similarly decreased in both groups. Hot pain and dull pain of NPS decreased more significantly in BoNT-A group than TA group.

Conclusion In the short-term, intra-articular BoNT-A shoulder injection maybe has the therapeutic effect on acute CRPS I related stroke. And the uptake ratio of blood pool phase of the hand of QTPBS may be useful to assess the therapeutic effect of CRPS after acute stroke.