Kannus 1992.

Methods	RCT, randomisation using sealed envelopes, double blind assessments with respect to injections of saline and glucosaminoglycan polysulphate High quality: Delphi score 5
Participants	53 patients attending the Tampere Research Station of Sports Medicine with chronic patellofemoral pain syndrome: duration of symptoms mean 16, SD 19 months, all unilateral 17 previous arthroscopy, 8 with pathologic changes in patellar cartilage, no correlation with symptoms 25 men 28 women Age: mean 27, SD 9
Interventions	Conservative treatment: no symptom‐producing activities for 6 weeks, isometric quadriceps tensioning exercises and straight leg raises, ice packs on patella if necessary, 20 mg piroxicam (NSAID) for 20 days (1) Conservative treatment only (n=16) (2) Conservative treatment and 5 weekly intra‐articular injections with saline and lidocaine (10 mg) (n=17) (3) Conservative treatment and 5 weekly intra‐articular injections with GAGPS (50 mg) and lidocaine (10 mg) (n=16)
Outcomes	Follow‐up assessments took place at 6 weeks and 6 months and again after 7 years subjective assessment: ‐ Pain and discomfort during activities on 0‐100 mm Visual Analogue Scale (0 = none, 100 = extremely intense pain) ‐ Overall evaluation of condition of the knee on 5 point scale (1 = asymptomatic, 5 = worse than before treatment) ‐ Level of physical activity on 4 point scale (1 = higher than before knee problem and 4 = unable to perform any physical activities) Combined subjective and functional evaluations of the knee: ‐ Lysholm scale (0‐100 point scale, 0 = worst score, 100 = best score) ‐ Tegner scale (0‐10 point scale, 0 = no physical activity possible, 10 = all kinds of activities possible) Symptoms on tests of function: ‐ Hopping on affected leg (4 point scale, 1 = no problem, 4 = unable) ‐ Duck walking (4 point scale, 1 = no problem, 4 = unable) ‐ 25 repetition full squat (1 = no squat without pain, 2 = 1‐5 without pain, 3 = 6‐10 without pain, 7 = > 25 squats without pain) Clinical evaluation: ‐ Pain during compression test (0‐4 point scale, 0 = none, 4 = intense) ‐ Crepitation during compression test (0‐4 point scale, 0 = none, 4 = intense) ‐ Pain during apprehension test (0‐4 point scale, 0 = none, 4 = intense) ‐ Physician's opinion of overall therapeutic effect (5 point scale, 1 = complete subjective, functional and clinical recovery and 5 = overall status worse than before treatment) Muscle strength: ‐ Isometric quadriceps muscle strength in 60 degrees of flexion using and isometric dynamometer Radiological signs after 7 years ‐ MRI and radiographs of both knees after 7 years, to look for both early and advanced signs of osteoarthritis in the patellofemoral joint ‐ Bone density of the distal part of the femur, the patella and proximal part of the tibia to determine whether PFPS had caused bone loss or osteopenia in the affected knee compared with the unaffected knee: a 5% deficit was deemed clinically important
Notes	2 patients were excluded after enrolment because they had osteoarthritis (group 1 and 3) 1 patient of group 3 never returned 1 patient of group 2 was excluded due to an adverse event: intense aseptic effusion (reactive synovitis) following first injection 45 of the 49 patients of the original study were reassessed after 7 years (Kannus 1999). Because analysis of the data showed no differences among the groups at 6 months the results of all groups were pooled for analysis at 7 years. The results of the 7 year follow‐up are therefore only included in the text of this review. MRI and radiograph assessment was blind as to which knee was affected
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ Adequate