Painful arthroplasty with disproportionate pain: Recognition and management of complex regional pain syndrome

Table 2 Summary of available evidence evaluating sympathetic nerve blocks in complex regional pain syndrome[12,18,31,33,35-37]

Ref.	Study type	Population	Arthroplasty specific	Block type	Take-home message	Duration of relief	Key limitations
Ferraro et al[31]	Overview of systematic reviews	Adults with CRPS	General CRPS	Multiple interventions including sympathetic blockade	Evidence remains low certainty; definitive benefit unclear	Variable	Limited high-quality trials
Lee et al[33]	Retrospective cohort	Lower-extremity CRPS	General CRPS	Lumbar sympathetic block with botulinum toxin A/B	Type B toxin produced longer pain relief	Approximately 15 days (type A) vs approximately 69 days (type B)	Small sample size; non-arthroplasty population
Hartrick et al[35]	Prospective observational study	CRPS patients	General CRPS	Sympathetic block	Early response associated with better outcomes	Variable	No standardized protocol; heterogenous population
Adam et al[12]	Case report	Multiple revision THA	THA	Sympathetic block	Marked pain reduction after failed treatments	Pain free at 6 months	Single case report
Zanotti et al[36]	Case report	Elective THA patients	THA	Sympathetic block	Progressive symptom resolution	Resolution by 8 months, symptom free at 6-year follow-up	Very small sample size
Royeca et al[37]	Case report	Post-TKA CRPS	TKA	Multimodal management (limited block data)	Highlights diagnostic difficulty and variable outcomes	Variable	Limited evidence; primarily descriptive
Harden et al[18]	Evidence-based review	CRPS patients	General CRPS	Sympathetic blockade	May provide temporary pain relief and facilitate rehabilitation	Variable	Limited high-quality evidence; variable response

Evidence types and methodological limitations are presented descriptively because this narrative review did not perform a formal systematic risk-of-bias or certainty-of-evidence assessment. CRPS: Complex regional pain syndrome; THA: Total hip arthroplasty; TKA: Total knee arthroplasty.