Wu 2014.

Methods	Unblinded, randomized, controlled trial Computer‐generated random sequence, sealed opaque envelopes Follow‐up: 6 months
Participants	Subjects: 79 participants enrolled (60 followed up to 6 months) from one hospital: Yan Chai Hospital, Hong Kong, China Operation: primary total knee replacement 2 groups (of 30 people each); 19 others excluded for various reasons before or after entering the study Mean age (SD): group 1, 68.9 (± 7.5); group 2, 68.8 (± 6.4) Sex: group 1, 8 males and 22 females; group 2, 8 males and 22 females
Interventions	Spinal anaesthesia (incompletely standardized: 58 participants received hyperbaric bupivacaine, one received levobupivacaine, and one isobaric bupivacaine; the volume also varied: 2.5 ± 0.3 mL in one group and 2.6 ± 0.3 mL in the other) Identical standardized multimodal analgesic regimen (if not contraindicated) including paracetamol, sustained release diclofenac, opioids (codeine or morphine), and drugs to prevent the side effects of the NSAIDs and opioids. Unclear how many surgeons performed the procedures. CFNB group: catheter inserted preoperatively using ultrasound and nerve stimulation guidance; success tested using ice after a bolus of 15 mL of 5 mg/mL levobupivacaine. Infusion of 8 to 12 mL/h of 0.08% levobupivacaine initiated postoperatively and continued for 4 days (until POD 3) PCA group: morphine IV PCA initiated postoperatively with 1 mg bolus, 5 min lockout, maximal 4h dose of 30 mg (modified for participants with sleep apnoea) Participants were not mobilized until POD 1
Outcomes	Postoperative knee pain, both at rest and during mobilization, twice a day until POD 3 Amount of morphine used until POD 3 Opioid side effects Patient satisfaction score from 1 to 10 (VAS) on the quality of analgesia and on the whole TKA pathway Progress of rehabilitation (start of mobilization, independent walking), Timed Up and Go test Ultrasound screening for DVT performed on all participants on POD 4 and 5 Knee Society scores preoperatively, upon discharge, then 6 weeks and 6 months after discharge
Funding source	Not provided
Declarations of interest	None reported
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“These 60 patients were randomized to the CFNB and PCA groups (30 patients in each), using computer‐generated random numbers. Subjects were divided into two groups (odd against even numbers generated by the computer)."
Allocation concealment (selection bias)	Low risk	"The case allocation was concealed in sealed envelopes and the mode of analgesia revealed to case anaesthetist and patient after the patient was included in the study.”
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated whether the outcome assessor was blinded to group allocation
Incomplete outcome data (attrition bias) All outcomes	High risk	"In all, 79 patients were recruited but 19 were excluded for various reasons . . . [R]eplacements were recruited using the permuted block technique." Some patients were excluded after entering the study for reasons such as failed spinal, infusion stopped, catheter dislodged, manpower limits, etc.
Selective reporting (reporting bias)	Low risk	All outcomes were reported, except for the Timed Up and Go test because of missing data