Nader 2012.

Methods	Unblinded, randomized, controlled trial Computer‐generated random allocation sequence Follow‐up: 12 months
Participants	Subjects: 62 participants enrolled (60 followed up to 12 months) from one university hospital: Northwestern University, Chicago, IL Operation: primary total knee replacement 2 groups (of 31 people each) Age: group 1, 65 (IQR 60 to 76); group 2, 64 (IQR 60 to 71) Sex: group 1, 13 males and 18 females; group 2, 7 males and 24 females
Interventions	All participants received spinal‐epidural anaesthesia (10 mg of 5 mg/mL isobaric bupivacaine intrathecally, epidural test dose 3 mL of 15 mg/mL lidocaine with 1:200,000 epinephrine) followed by epidural analgesia (continuous infusion of 3 mL/h of 1mg/mL bupivacaine with hydromorphone 10 mcg/mL, patient boluses of 3 mL with a lockout time of 15 minutes and an hourly maximum of 15 mL) until the morning of POD 1 Group 1 (CFA group): 10 mL bolus of 2.5 mg/mL ropivacaine injected into femoral perineural catheter (placed prior to spinal‐epidural) followed by 5 mL/h infusion of 1 mg/mL ropivacaine until the morning of POD 2; oral analgesic regimen as below for breakthrough pain Group 2 (OOA group): after end of epidural infusion, oral regimen only, as below No adjuvants Oral postoperative analgesic regimen in both groups: hydrocodone 10 mg plus paracetamol 325 mg every 4 to 6 hours for pain as needed; if participants could not achieve a VRSP < 4, the analgesic regimen was changed to sustained release oxycodone 10 mg every 12 hours plus oral hydromorphone 2 mg every 4 hours for breakthrough pain; not different between groups
Outcomes	Primary outcome: knee flexion at 1, 6 and 12 months Secondary outcomes: patient satisfaction during hospital stay, amount of opioid analgesic consumed, verbal rating of pain during hospital stay and follow‐up visits, health‐related quality of life, and functional outcome on POD 1, POD 2, POD 3, and at 1 month, 6 months, and 12 months after surgery Effectiveness of the regional analgesia is not reported
Funding source	Stryker Instruments, Inc. and departmental funds
Declarations of interest	None reported
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomization was determined using a computer‐generated random allocation sequence"
Allocation concealment (selection bias)	Low risk	"[G]roup membership was concealed by placing the assignment slip in an opaque envelope that was not opened until after informed consent was obtained."
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding. Participants in the CFA group received a femoral perineural catheter while participants in the OOA group did not.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No blinding. This is not explicitly stated, but it is possible that the investigators and the surgeon assessing the participants had access to the records that would show whether each participant had received a continuous femoral block.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 1 participant in each group lost to follow‐up after 1 month
Selective reporting (reporting bias)	Unclear risk	The difference in knee flexion on POD 3 and at 1 month is significant but only reported graphically, with no values given. While the components of the WOMAC score are reported as median (range), the scores themselves are not reported.