Zarezadeh 2012.

Methods	RCT
Participants	48 participants were enrolled in the study (age range 25 to 60 years; 27 male, 21 female) with clinical and neurophysiological evidence of ulnar nerve impairment at the elbow. The trial authors declare: "according to clinical and paraclinical tests, severe and moderate patients and mild group that did not respond to conservative treatment were operated"; however, they do not indicate how the severity was defined. Exclusion criteria included deformity or distortion of the cubital tunnel due to previous trauma to the elbow and recurrent cubital tunnel syndrome after previous surgery.
Interventions	Anterior subcutaneous transposition (24 participants), anterior submuscular transposition (24 participants)
Outcomes	Clinical outcomes: Yale Sensory Scale, MRC Scale VAS subjective evaluation of muscle atrophy
Conflicts of interest	None declared.
Study funding	None
Notes	Operations performed between October 2008 and March 2009. Single centre, Iran. Electrophysiological evaluation was performed before and 12 months after surgery, but no data are available.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "based on a random table numbers, generated by the random allocation software, the principal investigator allocated patients into two groups"
Allocation concealment (selection bias)	Unclear risk	Quote: "based on a random table numbers, generated by the random allocation software, the principal investigator allocated patients into two groups"
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "To prevent bias, all patients underwent double‐blind nerve conduction velocity studies, conducted by two neurophysiologists according to a standard protocol, before and after surgery". Comment: Despite this quote, the authors do not unequivocally state that the participants were blinded to the treatment.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "To prevent bias, all patients underwent double‐blind nerve conduction velocity studies". Comment: It is not specified if the clinical outcomes were assessed by a blinded examiner.
Incomplete outcome data (attrition bias) Clinical or neurophysiological outcome	Low risk	No participant was lost to follow‐up.
Selective reporting (reporting bias)	High risk	No neurophysiological data are available.
Other bias	High risk	The sample size was not calculated. The trial authors do not specify if the study was designed to be a non‐inferiority or a superiority trial.

MRC: Medical Research Council
 RCT: randomised controlled trial
 SD: standard deviation
 UNE: ulnar neuropathy at the elbow
 VAS: visual analogue scale