Yu 1992.

Methods	This was a randomised, double‐blind, internally‐controlled study. It was unclear if intention‐to‐treat analysis was conducted.
Participants	Inclusion criteria of the trial The trial included 10 participants with severe psoriatic nail dystrophy involving all fingernails. Of these 10 participants, 2 defaulted and were excluded before radiotherapy commenced. (There were 7 men and 1 woman; age range = 42 to 68 years; mean age = 55 years.)
Interventions	Superficial radiotherapy was administered to the distal phalanx of each individual finger of a randomly preselected hand. 3 fractionated doses of 150 cGy were administered every 2 weeks to a total of 450 cGy per fortnight (90 kV, 5 mA, half‐value layer 1.00 mm, focus skin distance 100 mm). The control hand was treated with 'sham' radiotherapy. The participants' nails were assessed at ‐10, 0, 10, 15, and 20 weeks (total of 30 weeks). They intend to keep these participants under review every third month over a period of 2 years in order to watch for a delayed response.
Outcomes	Outcomes of the trial Visual assessment: each nail was scored using a rating scale (0 = normal, 1 = slightly affected, 2 = moderately affected, 3 = severely affected) for pitting, onycholysis, subungual hyperkeratosis, and destruction of the nail plate. Range of scoring points: 0 to 12 Rate of nail growth: in mm per week using an electronic calliper Nail thickness using an electronic calliper
Notes	None of the participants were receiving active treatment for their nail dystrophy.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Superficial radiotherapy was administered to a randomly preselected hand." Comment: This was probably done.
Allocation concealment (selection bias)	Unclear risk	Comment: The paper provided insufficient details.
Blinding (performance bias and detection bias) Clinician/ Investigator	Unclear risk	Quote: "...double blind trial, neither the participants nor the assessor were aware which side was being active treated until the end of the trial." Comment: It was unclear if the investigator was the blinded assessor.
Blinding (performance bias and detection bias) Participants	Low risk	Quote: "...double blind trial, neither the participants nor the assessor were aware which side was being active treated until the end of the trial." Comment: 'Sham radiotherapy' was administered to the control hand.
Blinding (performance bias and detection bias) Outcome assessor	Low risk	Quote: "...double blind trial, neither the participants nor the assessor were aware which side was being active treated until the end of the trial."
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 participants defaulted and were excluded before radiotherapy
Selective reporting (reporting bias)	Low risk	The trial reported all of the expected outcomes.
Other bias	Unclear risk	There was no information about the baseline characteristics.