O'Neill 1996

Methods	Treatment allocation by birth month Independent, non blinded assessment Follow‐up: mean 42 months (24 to 60 months) [1996 publication]; mean 102 months (72 to 121 months) [2001 publication] Loss to follow‐up: 1 PT (2 incision), 1 HT (2 patients in total; excluded from analysis) Graft re‐ruptures (traumatic): 2 PT (1 incision), 2 HT (4 patients in total; included in analysis)
Participants	USA 127 participants (1996 publication) / 229 participants (2001 publication) with acute (< 3 weeks) or chronic (> 3 weeks), isolated unilateral ACL tears Group allocation data for 125 participants (1996 publication) / 225 participants (2001 publication) PT (1 incision): n = 45, mean 28 years (14 to 56 years), 28 males / 17 females (1996 publication); n = 75 (2001 publication) PT (2 incision): n = 40, mean 26 years (15 to 49 years), 26 males / 14 females (1996 publication); n = 75 (2001 publication) HT: n = 40, mean 27 years (14 to 56 years), 27 males / 13 females (1996 publication); n = 75 (2001 publication) Loss to follow‐up: 1 PT (1 incision) and 1 PT (2 incision) and 2 deaths (group assignment not reported). Failures (traumatic, included in the analysis) : 2 PT (2 incision) and 2 HT (1996 publication) / 5 PT (1 incision), 4 PT (2 incision) and 1 HT(2001 publication).
Interventions	Arthroscopically‐assisted ACL reconstruction with: 1. Patellar tendon: 1 or 2 incisions, (proximal fixation ‐ interference screw (9 x 25 mm); tibial fixation ‐ interference screw, or barbed staples for long grafts (17 cases)) versus 2. Hamstring tendon: semitendinosus/gracilis tendons (2 strands; 2 incisions; proximal and tibial fixation ‐ barbed staples)
Outcomes	Mean 42 months follow‐up for: Lysholm, KT‐2000 (Maximum Manual), range of motion, Lachman (0/1/2/3); single‐leg hop, return to activity; failures; strength with Biodex, patellofemoral crepitus; IKDC; radiographs. Mean 102 months follow‐up for: KT‐2000 (Maximum Manual), return to activity; failures; strength with Biodex, patellofemoral crepitus; IKDC; radiographs.
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	Allocation by birth month.
Allocation concealment (selection bias)	High risk
Blinding (performance bias and detection bias) All outcomes	High risk
Incomplete outcome data (attrition bias) All outcomes	High risk	The two patients lost to follow‐up and two deaths were excluded from the analysis.
Selective reporting (reporting bias)	High risk	The authors failed to report the following outcomes in their 2001 publication on the larger groups of patients: Return to activity; Lachman; range of motion; patellofemoral crepitus; Lysholm score and single leg hop.
Other bias	High risk	Recruitment in this trial continued beyond the point where the results of the original publication (1996) were likely analysed. This may have resulted in a selection bias in the 2001 publication.