Eriksson 2001

Methods	Closed envelopes, but randomization method not described Independent, but non blinded assessment Mean follow‐up: 33 months (median 31 months) Loss to follow‐up: 4 patients in total (excluded from analysis) Graft re‐ruptures (all traumatic): 2 PT (no revision surgery), 3 HT (no revision surgery), 1 HT requiring revision surgery (total of 10 patients excluded from the analysis)
Participants	Sweden 164 participants with chronic (> 2 months), isolated unilateral ACL tears and an overall mean age of 25.7 years (+/‐6.9 years), PT: n = 84, mean 25 years (15 to 40 years), 41 males / 43 females HT: n = 80, mean 27 years (16 to 45 years), 55 males / 25 females
Interventions	Arthroscopic ACL reconstruction with: 1. Patellar tendon (single incision; proximal fixation ‐ non‐absorbable interference screw (7 x 20 mm); tibial fixation ‐ non‐absorbable interference screw (9 x 20 mm)) versus 2. Hamstring tendon: semitendinosus tendon (4 strands; single incision; proximal fixation ‐ Endobutton; tibial fixation ‐ screws)
Outcomes	Mean 33 months follow‐up for: Stryker laxity test (9.08 kg, 18.16 kg); range of motion; pivot shift; Lachman (as defined by the IKDC 1995); single‐leg hop; Tegner activity level; Lysholm; patellofemoral pain; IKDC; patient satisfaction; knee function (VAS)
Notes	Additional information received from Eriksson comprised a description of the allocation concealment methodology, lack of a sample size calculation, and the mean age for each group. Eriksson also provided individual patient data for the following outcomes: Tegner activity level, Lysholm, single leg hop, IKDC, ROM of index and contralateral knees, flexion and extension deficits, Stryker strength (20lbs) for index and contralateral knees; Lachman; anterior and posterior drawer tests; pivot shift test; MCL and LCL stability; patellofemoral, medial and lateral crepitus; harvest site pathology; thigh circumference of the index and contralateral legs; pain.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details
Allocation concealment (selection bias)	Low risk	Closed envelopes opened within one hour of surgery.
Blinding (performance bias and detection bias) All outcomes	High risk	Independent assessor.
Incomplete outcome data (attrition bias) All outcomes	High risk	The authors excluded patients who were lost to follow‐up and those who suffered a re‐rupture, of the ACL graft.
Selective reporting (reporting bias)	Low risk
Other bias	High risk	Gender distribution was different between the two groups at baseline.