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Comparing knee stability, subjective function, and OA development between DB & SB ACL reconstruction

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Comparing knee stability, subjective function, and OA development between DB & SB ACL reconstruction

Vol: 7| Issue: 5| Number:12| ISSN#: 2564-2537
Study Type:Therapy
OE Level Evidence:2
Journal Level of Evidence:N/A

Single-Bundle versus Double-Bundle Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Controlled Trial with 6-Year Follow-up

J Knee Surg. 2017 Nov;30(9):898-904

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60 patients requiring anterior cruciate ligament (ACL) reconstruction were randomized to either double-bundle reconstruction or single-bundle reconstruction. Patients were assessed for instrumented anteroposterior knee laxity (KT-2000), subjective function, objective functional performance on hop tests, and osteoarthritis development over 6-year follow-up. Results demonstrated no significant differences in any outcome measure between the two groups. One case of rerupture was recorded, occurring in the DB reconstruction group.

Publication Funding Details +
Not Reported
None disclosed

Risk of Bias


Reporting Criteria


Fragility Index


Was the allocation sequence adequately generated?

Was allocation adequately concealed?

Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?

Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?

Blinding Patients: Was knowledge of the allocated interventions adequately prevented?

Was loss to follow-up (missing outcome data) infrequent?

Are reports of the study free of suggestion of selective outcome reporting?

Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?

Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?

Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?

Yes = 1

Uncertain = 0.5

Not Relevant = 0

No = 0

The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.




Outcome Measurements


Inclusion / Exclusion


Therapy Description



Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65

The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.

Why was this study needed now?

A prevalent comparison in research on outcomes following anterior cruciate ligament is single-bundle versus double-bundle reconstruction. More recently, emphasis has been placed on whether specific technical factors may influence if differences are found between groups or not.

What was the principal research question?

In anterior cruciate ligament reconstruction, does double-bundle reconstruction, using an independent tunnel drilling technique, provide significantly greater anteroposterior knee stability compared to single-bundle reconstruction, using a transtibial technique, assessed over 6-year follow-up?

Study Characteristics -
60 patients, 16-45 years of age, with a complete rupture of the ACL and scheduled for arthroscopic reconstruction. Cases of significant knee deformity, or requiring concomitant meniscal repair or mensicectomy were excluded. All surgeries were completed using semitendinosus and gracilis autografts.
DB group: Double-bundle reconstruction was performed. The anteromedial and posterolateral tibial tunnels were drilled using a standard tibial guide. The posterolateral femoral tunnel was drilled using an outside-in technique with a femoral guide, and the anteromedial femoral tunnel was drilled using a transtibial method through the posterolateral tibial tunnel. Femoral fixation was achieved using an interference screw for the posterolateral bundle, and an EndoButton for the anteromedial bundle. Tibial fixation was achieved using staples and interference screws. (n=30; 27 analyzed) (Mean age: 26.4+/-8.5)
SB group: Single-bundle reconstruction was performed using a transtibial drilling technique. Femoral fixation was achieved using an EndoButton, and tibial fixation was achieved using an interference screw. (n=30; 26 analyzed) (Mean age: 28.3+/-6.2)
Anteroposterior knee stability was assessed using a KT-2000 arthrometer, and reported as side-to-difference. Subjective function was assessed using the Lysholm score and the International Knee Documentation Committee (IKDC). Functional performance was assessed using the single-leg hop, the crossover triple hop, and timed hop tests. Development of osteoarthritis (OA) was examined using radiographs, and classified using the Kellgren-Lawrence grade.
RCT; Single-surgeon, Single-center
Follow-up was scheduled for 6, 12, 36, and 72 months.

What were the important findings?

  • At final follow-up, there was no significant difference in side-to-side difference KT-2000 results between the DB group (1.4+/-0.6mm) and the SB group (1.3+/-0.8mm) (p=0.74).
  • At final follow-up, there was no significant difference in Lysholm score between the DB group (96.4+/-17.3) and the SB group (94.2+/-15.3) (p=0.36).
  • At final follow-up, there was no significant difference in IKDC score between the DB group and the SB group (p=0.23).
  • At final follow-up, there were no significant differences between the DB group and the SB group in single hop distance (p=0.1528), crossover top distance (p=0.14) and the timed hop test (p=0.16).
  • There was one case of rerupture (DB group).
  • Medial compartment OA development was observed in 3 patients of the DB group and 2 patients of the SB group.

What should I remember most?

In ACL reconstruction, there was no significant difference in 6-year AP stability, subjective functional outcome, or objective functional performance between cases completed using double-bundle, independent tunnel drilling reconstruction and cases completed using single-bundle, transtibial drilling reconstruction.

How will this affect the care of my patients?

Mid-term follow-up to 6-year data appears to suggest that outcomes may be similar for double-bundle ACL reconstruction and single-bundle ACL reconstruction. There does not appear to be significant differences in subjective or objective function, AP stability, or OA development between the two techniques. Nonetheless, this study is one of only a few randomized trials to extend follow-up beyond 5 years in a comparison between double- and single-bundle reconstruction. Accordingly, additional data is needed to verify if there are indeed any differences in outcome between the two techniques.

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Anonymous 2018-01-10

Orthopaedic Surgeon - Canada

not surprised

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