A randomized clinical trial comparing patellar tendon, hamstring tendon, and double-bundle ACL reconstructions: patient-reported and clinical outcomes at 5-year follow-up

Key points

1. 01Quality-of-life scores at 2 years were statistically identical across all three graft types (PT=84.6, HT=82.5, DB=82.4 out of 100)
2. 02Patellar tendon reconstruction produced significantly less knee laxity (KT-1000 side-to-side difference 1.86 mm vs 2.97 mm for HT and 2.65 mm for DB)
3. 03IKDC Objective grades, pivot shift, single-leg hop, Tegner activity, and Cincinnati Occupational scores were not statistically different between groups
4. 04Double-bundle reconstruction requires longer operative time (median 85 min vs 68 min for HT and 74 min for PT) with no additional patient benefit
5. 05Blinding was successfully achieved: patients guessed graft type correctly only 51% of the time and the independent examiner 46% of the time

How it was conducted

Design

Prospective double-blind randomized clinical trial with intraoperative computer-generated allocation, stratified by injury chronicity

Participants

330 patients aged 14-50 years with isolated ACL deficiency, enrolled at the University of Calgary Sport Medicine Centre, 2004-2010

Groups

110 per group: (1) patellar tendon (PT), (2) quadruple-stranded hamstring tendon (HT), (3) double-bundle using hamstring tendons (DB)

Primary outcome

ACL Quality-of-Life (ACL-QOL) questionnaire score (0-100) at minimum 2-year postoperative follow-up

Secondary outcomes

IKDC subjective and objective scores, KT-1000 arthrometer side-to-side difference, pivot shift, range of motion, Tegner activity, Cincinnati Occupational Scale, single-leg hop

Follow-up

Assessments at baseline, 6 and 12 months, and 1 and 2 years postoperatively

What they found

• ACL-QOL scores at 2 years were not significantly different between groups (P=0.591): PT mean 84.6 (SD 16.6, 95% CI 81.4-87.8), HT mean 82.5 (SD 17.7, 95% CI 79.2-85.9), DB mean 82.4 (SD 17.5, 95% CI 79.1-85.7)
• All groups improved significantly in ACL-QOL over time (P=0.001)
• KT-1000 arthrometer side-to-side differences at 2 years were significantly different between PT and HT (P=0.002) and PT and DB (P=0.044): PT mean 1.86 mm (SD 2.5, 95% CI 1.4-2.3), HT mean 2.97 mm (SD 2.1, 95% CI 2.6-3.4 reported as 3.0), DB mean 2.65 mm (SD 2.4, 95% CI 2.2-3.1 reported as 2.7); overall ANOVA P=0.002
• IKDC Objective grades at 2 years showed no statistically significant difference between groups (P=0.658 with LOCF, P=0.630 without imputed data)
• IKDC Subjective scores at 2 years were not significantly different: PT mean 84.6 (SD 13.8), HT mean 85.3 (SD 11.6), DB mean 84.2 (SD 11.8)
• Pivot shift grades at 2 years were not significantly different between groups
• Single-leg hop test at 2 years showed no significant difference (P=0.761): PT 95.4% of opposite knee (SD 9.8), HT 96.3% (SD 26.5), DB 94.4% (SD 13.4)
• Tegner activity level of 6 or greater at 2 years was not significantly different (P=0.814): PT 84%, HT 80%, DB 83%
• Mean operative times: PT 75.3 min (SD 14.7), HT 67.8 min (SD 14.6), DB 88.0 min (SD 14.9)
• Correct graft-type guesses: 51% by patients overall, 46% by the independent examiner, confirming successful blinding

Limitations

• Single-surgeon, single-centre study limits generalizability; results may not apply to surgeons earlier in their learning curve with double-bundle technique
• Follow-up was a minimum of 2 years; longer-term outcomes including rates of osteoarthritis and graft re-rupture are not reported here
• Patients and the independent examiner were unblinded at the 2-year visit, so outcomes beyond 2 years may be subject to unblinding bias
• The study was not powered specifically to detect small differences in secondary outcomes, and some subgroup comparisons may be underpowered

Why it matters

For patients

Patients undergoing ACL reconstruction can expect similar recovery and quality of life regardless of whether their surgeon uses a patellar tendon, hamstring tendon, or double-bundle technique at 2 years.

For clinicians

There is no quality-of-life benefit to choosing double-bundle over single-bundle ACL reconstruction at 2 years, and patellar tendon grafts produce less residual knee laxity on objective testing, though this did not translate to better patient outcomes.

For readers

This well-conducted double-blind RCT fills a key evidence gap by directly comparing all three main autograft strategies, using a disease-specific patient-reported outcome as the primary measure with adequate blinding.