Table 1

Methodological characteristics, inclusion and exclusion criteria, and follow-up completion rates of the included studies

AuthorStudy typeRandomisation methodBlinding methodAllocation concealmentStatistical power calculationBaseline comparisonInclusion criteriaExclusion criteriaFollow-up completion
Berrazueta et al 13 Double-blind placebo-controlled RCT.Not stated.Not stated.Not stated.No.Not done—greater pain and joint restriction in GTN group compared with control group as reported by Cumpston et al. 14 Acute supraspinatus tendintis (symptoms of <7 days) with tenderness and limitation of motion with increased pain with abduction.Chronic shoulder pain, cervical spain/nerve root/brachial plexus lesions, cardiac/pulmonary/systemic disease, bone lesions or calcification at tendon insertion on X-ray, glaucoma, hypersensitivity to nitrates and NSAIDs.100%
Pons et al 32 Double-blind placebo-controlled RCT.Random number table.Not stated.Not stated.No.No difference.Acute supraspinatus tendintis (symptoms of <6 weeks, pain on moving arm 60°–120° abduction, positive impingement test, Jobe, Gerbe or Pate tests, no response to 1-week NSAIDs treatment.Adhesive capsulitis, biceps tendinitis, allergy/intolerance to GTN and those receiving GTN patches for heart disease.100%
Steunebrink et al 35 Double-blind placebo-controlled RCT.Sealed, coded envelopes; block randomisation (four participants per block).Not stated.Coordinated by independent physician;
data after randomisation stored at secret location.
sample size adequate for 80% power.
Significantly higher VAS score during activities in control versus treatment group.18–40 years, clinical diagnosis patellar tendinopathy (pain with activity or tenderness/thickening).Symptoms of >24 months, VISA-P score >80, previous surgery or injection, previous eccentric programme in last 2 years, serious illness, pregnancy and contraindications to GTN.82.5%
Giner-Pascual et al 33 Double-blind placebo-controlled RCT.Allocation based on hour and date of clinic appointment.Not statedNot statedNoGTN group older than control group;
no baseline comparison of outcome measures.
>18 years, complete motor paraplegia, full-time wheelchair user, symptoms >3 months, diagnosis on MRI or US.Tetraplegia, incomplete paraplegia, treatment with NO drugs and heart disease or hypotension.91% (only 66.7% completed treatment)
Paoloni et al 29 Double-blind placebo-controlled RCT.‘Coded randomisation’.Active and placebo patches indistinguishable from each other.Randomisation supervised by senior pharmacist.Yes;
sample size adequate for 90% power.
No difference.>18 years, supraspinatus tendinopathy clinically (signs of impingement and pain in empty can position) and on MRI.Symptoms of <3 months, pregnancy, previous surgery, previous shoulder dislocation, distal neurology, IHD and steroid injection last 3 months.91%
Kane et al 30 Single-blinded, non-placebo-controlled RCT.‘Sealed envelopes’.Not stated.Not stated.No.No difference.Achilles tendinopathy confirmed on US and MRI.Symptoms of <3 months, previous surgery or injection and contraindications to GTN.90%
Paoloni et al 28 Double-blind placebo-controlled RCT.Not stated.Not stated.Randomisation controlled by senior pharmacist.Yes;
sample size adequate for 90% power.
Significantly lower ankle plantar flexor mean total work in treatment than placebo group.>18 years, diagnosis of non-insertional Achilles tendinopathy both clinically (insidious onset Achilles pain, tender nodule 2–6 cm proximal to calcaneal insertion) and radiologically (US scan with no tear).Symptoms of <3 months, previous surgery, previous ankle dislocation, distal neurology, steroid injections in last 3 months and pregnancy.89%
Ozden et al 34 Double-blind placebo-controlled RCT.Not stated.Not stated.Not stated.Yes;
sample size adequate for 80% power.
No difference.Tenderness and pain over lateral epicondyle, positive Mill’s sign, positive chair lift test, symptoms of >3 months and resisted wrist extension.Surgery, effusion, radiculopathy, ulnar entrapment, fracture, infection, high ESR and injections.100%
Paoloni et al 31 Double-blind, placebo-controlled RCT.Stratified computer-generated randomisation.Placebo and active patches identical in appearance.Not stated.Yes;
sample size adequate for 80% power.
No difference in demographics;
statistical analyses of outcome measures between groups not performed/stated.
18–70 years, symptoms of >3 months, VAS score >4/10 with provocative testing (ORI-TETS).BMI >38, requirement of oral or topical analgesia, injection last 3 months, worker’s compensation cases, previous use of GTN, cardiac disease, pregnancy and previous surgery/fracture/dislocation.88%
Paoloni et al 27 Double-blind placebo-controlled RCT.‘Coded randomisation’.Not stated.Randomisation supervised by senior pharmacist.Yes;
sample size adequate for 90% power.
No difference in dropouts or outcome measures; statistical comparison of demographics between groups not reported.>18 years.Surgery, previous dislocation of wrist/elbow, injection in last 3 months and distal neurology.86%
  • BMI, body mass index; ESR, erythrocyte sedimentation rate; GTN, glyceryl trinitrate; IHD, ischaemic heart disease; NO, nitric oxide; NSAIDs, non-steroidal anti-inflammatory drugs; ORI-TETS, Orthopaedic Research Institute Tennis Elbow Testing System; RCT, randomised controlled trial; US, ultrasound; VAS, visual analogue scale; VISA-P, Victorian Institute of Sports Assessment – Patella.