Liguori 1998.

Methods	Randomization: yes Participant blinding: yes Provider blinding: no Assessor blinding: yes Dropouts: 3 outcomes not reported
Participants	Country: USA ASA: I, II, and III Gender: men and women Mean age: lido: 38 (SD 12); mepi: 42 (SD 10) years Procedures: arthroscopy Ambulatory surgery: yes Surgical positioning: supine Number of participants: 60
Interventions	Drug 1: 2% lido, baricity unclear, fixed dose (3 mL) Drug 2: 1.5% mepi, baricity unclear, fixed dose (3 mL) Needle: 27 G, pencil‐point
Outcomes	TNS at 1–2 days
Notes	Follow‐up duration: 2–5 days Follow‐up method: telephone contact TNS therapy: NSAIDs TNS resolution: duration 1–5 days
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "the patients were assigned using a random‐number table to receive either 2% 3 ml (60 mg) lidocaine… or 1.5% 3 ml (45 mg) mepivacaine…"
Allocation concealment (selection bias)	Unclear risk	No mention of allocation concealment.
Participant blinding (performance bias and detection bias)	Low risk	Quote: "…we decided to re‐evaluate mepivacaine… in a randomized, double‐blind comparison with isobaric 2% lidocaine…"
Provider blinding (performance bias)	Low risk	Quote: "…we decided to re‐evaluate mepivacaine… in a randomized, double‐blind comparison with isobaric 2% lidocaine…"
Assessor blinding (detection bias)	Low risk	Quote: "patients were contacted… by one of the investigators who was blinded to group assignment."
Incomplete outcome data (attrition bias) All outcomes	High risk	3 participants in lido group lost to follow‐up. Dropout outcomes not reported.
Selective reporting (reporting bias)	Unclear risk	Study protocol not available.