Raatikainen 1990.

Methods	RCT, randomisation method not defined, double blind High quality: Delphi score 5
Participants	31 consecutive patients with patellofemoral pain attending sports clinic at Deaconess Institute 22 men and 7 women Inclusion criteria: resisted patellar movement causes pain, arthroscopy revealed patellar cartilage lesions Exclusion criteria: other pathology at arthroscopy, corticosteroid use or glucosaminoglycan polysulphate within 40 days, NSAIDs within 7 days of commencement of trial, pregnant or nursing mothers, age under 18 years, contraindication for GAGPS.
Interventions	All patients received standardised quadriceps training after 6 week injection period. Paracetamol allowed as an escape analgesic. Baseline arthroscopy (1) 12 intramuscular injections of 50 mg glucosaminoglycan polysulphate (Arteparon) (n=15) (2) Placebo ‐ 12 intramuscular injections with physiologic saline (n=14) Arthroscopy repeated after 1 year
Outcomes	All outcomes were assessed at baseline, 6, 10 and 58 weeks on a 4 point scale (0=none, 1=slight, 2=moderate, 3=severe or extensive) Pain on palpation, pain on pressing patella against femur, pain during apprehension test, pain going downstairs, pain when squatting, hindrance to normal life, hindrance to sports activities, overall therapeutic effect, change from initial damage assessed by arthroscopy
Notes	1 patient was excluded due to trauma after 6 injections (treatment unknown), 1 patient dropped out after 8 injections (treatment unknown) 1 patient glucosamine group lost to follow‐up at final assessment, 2 in placebo group refused re‐arthroscopy (1 asymptomatic and 1 with moderate to severe clinical symptoms) Clinical results were dichotomised by the authors to indicate "good clinical results"
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear