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Femoral tunnel enlargement reduced with autologous ruptured tissue vs conventional DB ACLR

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Femoral tunnel enlargement reduced with autologous ruptured tissue vs conventional DB ACLR

Vol: 3| Issue: 6| Number:24| ISSN#: 2564-2537
Study Type:Therapy
OE Level Evidence:2
Journal Level of Evidence:2

Reduction of tunnel enlargement with use of autologous ruptured tissue in anterior cruciate ligament reconstruction: a pilot clinical trial

Arthroscopy. 2014 Apr;30(4):468-74. doi: 10.1016/j.arthro.2013.12.014.

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10 patients with ACL deficiencies were randomized to undergo double-bundle ACLR with either autologous ruptured ACL tissue sutured to grafts or conventional grafts, to compare magnitude of tunnel enlargement and clinical outcomes. Results indicated a significant decrease in femoral tunnel enlargement between groups, favouring the ruptured tissue group. Tibial tunnel enlargement ratios were similar between groups. Clinical outcomes were also not significantly different between groups.

Publication Funding Details +
Not Reported
Company Employee

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?

Recent developments in anterior cruciate reconstruction have focused on achieving anatomic reduction of the AM and PL bundles with hamstring grafts. However, while patients enjoy favourable outcomes, treatment can lead to significant tunnel enlargement and complicate ACL revision surgeries in the long-term. Recently, researchers have observed properties of tendon-bone healing in ruptured ACL tissue (i.e. CD34+ cells). Applications in animal studies have demonstrated a capacity for healing and ability to reduce magnitude of tunnel widening. This study aimed to pilot a technique that utilizes autologous rupture ACL tissue as a graft in a human clinical study.

What was the principal research question?

Does the use of a graft, with autologous ruptured ACL tissue sutured to its ends, in anterior cruciate ligament reconstruction decrease tunnel enlargement and improve clinical results when compared to conventional ACLR, 2 years after treatment intervention?

Study Characteristics -
10 Patients between the ages of 15 and 40 with recent (<3 months) ACL deficiency (positive Lachman and pivot-shift test and MRI) were included. (n=10) The ruptured site of the remnant ACL was harvested exclusively in both groups. Semitendinosus tendon was harvested and subsequently processed into doubled semitendinous tendons as grafts for the AM and PL bundles. Double-bundle ACLR was performed creating 2 femoral and 2 tibial tunnels for anatomic reconstruction of the AM and PL bundles.
Ruptured tissue DB ACLR: The previously harvested remnant ruptured ACL tissue was divided into 4 parts and sutured to the distal-most and proximal-most 15-mm portions of the doubled-bundle grafts. Anatomic DB ACLR was performed using these grafts. (n=5, 2 males 3 females; Mean age: 23.6 +/- 5.1 years)
Conventional DB ACLR: Anatomic DB ACLR was performed using doubled semitendinous tendon grafts. (n=5, 3 males 2 females; Mean age: 27.4 +/- 7.4 years)
The primary outcome was magnitude of tunnel enlargement, measured with 3-D multi-detector row computed tomography (MCDT). The secondary outcomes included the Lysholm score, and knee stability with the Lachman and pivot-shift tests (side-to-side difference between injured and contralateral knee).
RCT: Prospective; Pilot; Assessor-blind
Tunnel enlargement was measured at 3 weeks and 1 year postoperative. Lysholm scores and knee stability were assessed at 2 years postoperative.

What were the important findings?

  • Tunnel enlargement was significantly less in the ruptured tissue group compared to the conventional (control) group in both femoral tunnels (AM and PL). Femoral AM tunnel enlargement ratios were 84.6% +/- 15.9 and 119.5% +/- 24.1 in the ruptured tissue and control groups respectively (p=0.0283). Ratios for the PL tunnel were 84.2% +/ -14.0 compared to 151.3% +/- 23.8, respectively (p=0.0090).
  • Tunnel enlargement for femoral AM and PL tunnels were not significantly different between groups. Enlargement ratios for tibial AM tunnel were 71.0% +/- 11.2% versus 77.8% +/- 15.4% for the ruptured tissue group and control group, respectively, and 65.8% +/- 10.8% versus 96.9% +/- 30.5 for the PL tunnel (p>0.05 for both comparisons).
  • Clinical outcome measures at 2 years postoperative did not differ significantly between the ruptured tissue group and control group: Mean Lysholm scores were 92.6 vs 93.0, respectively, anterior knee stability 1.4 vs 1.0, and pivot-shift test results 4/5 in both groups (p>0.05 for all).

What should I remember most?

Tunnel enlargement of the femoral AM and PL tunnels were both significantly reduced in the ruptured tissue group compared to the conventional group. Tibial tunnel enlargement was comparable between techniques. Additionally, Lysholm scores, anterior knee stability, and pivot-shift tests were not significantly different between groups.

How will this affect the care of my patients?

Double-bundle ACLR using grafts of autologous ruptured ACL tissue sutured to doubled semitendinosus tendons appeared to yield less femoral tunnel widening while providing similar clinical outcomes when compared to a conventional technique. Findings from this pilot study warrant larger next-phase trials in populations of a wider age range. Additionally, further research is needed to elicit the healing mechanism of this technique.

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