Marder 1991

Methods	Treatment allocation by one‐to‐one alternating sequence Unblinded assessment Mean follow‐up: 29 months (24 to 42 months) Loss to follow‐up: 3 PT and 5 HT (excluded from analysis) Graft re‐ruptures: 1 PT and 1 HT (included in analysis)
Participants	USA 80 participants with chronic ACL deficiency, including 2 patients with previous ACL repair in the PT group PT: n = 37, mean 21.6 years (16 to 35 years), 24 males / 13 females HT: n = 35, mean 23.8 years (17 to 41 years), 26 males / 9 females
Interventions	Arthrocopic ACL reconstruction with: 1. Patellar tendon (2 incisions, proximal and tibial fixation ‐ posts and washers) versus 2. Hamstring tendon: semitendinosus/gracilis tendons (4 strands; 2 incisions; proximal and tibial fixation ‐ posts and washers)
Outcomes	Mean 29 months (24 to 42 months) follow‐up for: Zarins‐Rowe subjective rating score, average out of 50 points; proportion of patients with giving way or apprehension and knee pain; proportion of patients who returned to their pre‐injury activity level, had 2+ or greater patellofemoral crepitus or presence of an effusion; range of motion reported as a proportion of patients with a loss of extension or flexion; Lachman test (reported as a proportion of patients by grade (0/1+/2+/3+/4+) and as a mean value; pivot shift test (reported as a proportion of patients by grade (0/1/2/3/3+) and as a mean value; static stability with KT‐1000 at 90 N reported as a proportion of patients by grade and as a mean value; isokinetic testing using Cybex dynamometer at 60 degrees/sec.
Notes	No additional methodological information or individual patient data were received from the authors.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	One‐to‐one alternating sequence.
Allocation concealment (selection bias)	High risk
Blinding (performance bias and detection bias) All outcomes	High risk	No attempt to blind assessors or patients.
Incomplete outcome data (attrition bias) All outcomes	High risk	No information on lost to follow‐up patients.
Selective reporting (reporting bias)	High risk	Static stability testing using KT arthrometer only at 90 Newtons. Ordinal data were analysed as continuous and parametric statistics utilized (e.g. Lachman, pivot shift and KT arthrometer testing). No baseline information on patients lost to follow‐up.
Other bias	High risk	No inclusion or exclusion criteria were specified. Two patients in the patellar tendon group had a previous ACL repair prior to the reconstruction.