An interventional study of ACL Reconstruction with a Biocomposite Screw and ACL Reconstruction using a PEEK Screw in ACL - Anterior Cruciate Ligament Rupture, sponsored by Austrian Workers Compensation Board Styria. Not yet recruiting at 1 site in Austria. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-10-05.
Sponsored by Austrian Workers Compensation Board Styria · Not applicable, Interventional, and Treatment
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This prospective, randomized controlled trial will compare three tibial interference screw types used for graft fixation during primary anterior cruciate ligament (ACL) reconstruction: a polyetheretherketone (PEEK) screw, a biocomposite screw, and an allograft bone screw. Although interference screws are widely used for tibial fixation, the optimal screw material remains uncertain, particularly regarding its effect on tibial tunnel widening and graft incorporation.
Adult patients undergoing primary ACL reconstruction with a quadriceps tendon autograft using a standardized surgical technique will be randomly assigned to one of the three tibial fixation methods. The primary outcome is tibial tunnel widening measured by computed tomography (CT) 12 months after surgery. Secondary outcomes include graft integration assessed by magnetic resonance imaging (MRI) and patient-reported clinical outcomes, including the Lysholm, Tegner, KOOS, and ACL-Return to Sport after Injury (ACL-RSI) scores, collected during routine follow-up. The study aims to determine whether allograft bone screws reduce tunnel widening and improve graft integration compared with PEEK and biocomposite screws while maintaining comparable clinical outcomes.
For the **ClinicalTrials.gov Detailed Description**, you generally want a more comprehensive description of the rationale, design, interventions, and objectives without reproducing the entire protocol. Here's a version suitable for direct use:
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**Detailed Description**
Anterior cruciate ligament (ACL) reconstruction is the standard surgical treatment for symptomatic ACL rupture, with interference screw fixation being the most commonly used method for tibial graft fixation. While current fixation techniques provide reliable mechanical stability, the optimal screw material remains uncertain. Commonly used polyetheretherketone (PEEK) screws are biologically inert and provide durable fixation but do not integrate with surrounding bone. Biocomposite screws are designed to gradually resorb while promoting bone ingrowth; however, their degradation characteristics have been associated with variable tunnel widening. More recently, allograft bone interference screws have been introduced as a biological alternative that may allow complete osseous incorporation while maintaining adequate initial fixation. Clinical evidence directly comparing these three fixation methods remains limited, particularly regarding their effects on tibial tunnel widening, graft incorporation, and patient outcomes.
This prospective, single-center, randomized controlled trial will compare tibial fixation using a PEEK screw, a biocomposite screw, or an allograft bone screw in patients undergoing primary ACL reconstruction. All participants will undergo reconstruction using a standardized SAMBBA technique with an ipsilateral quadriceps tendon autograft. Femoral fixation will be identical in all patients, with only the tibial interference screw differing between treatment groups. Participants will be randomized in a 1:1:1 allocation ratio using sealed envelopes. Patients, physiotherapists, and outcome assessors will remain blinded to treatment allocation throughout follow-up.
The primary endpoint is tibial tunnel widening measured on computed tomography (CT) 12 months after surgery. Secondary endpoints include graft incorporation assessed by magnetic resonance imaging (MRI) according to the method described by Putnis et al., as well as validated patient-reported outcome measures including the Lysholm Score, Tegner Activity Scale, Knee Injury and Osteoarthritis Outcome Score (KOOS), and ACL-Return to Sport after Injury (ACL-RSI). Clinical and radiographic follow-up will be performed according to the study schedule over 12 months after surgery.
The study is designed to determine whether allograft bone interference screws reduce tibial tunnel widening and improve biological graft integration compared with conventional PEEK and biocomposite screws while maintaining equivalent clinical outcomes. The findings are expected to provide high-quality evidence to guide the selection of tibial fixation devices in primary ACL reconstruction.
625 studies on the registry are indexed under Anterior Cruciate Ligament Injuries; 192 are open to participants now.
This study's planned enrollment of 33 is below the median of 56 across 458 interventional studies indexed under Anterior Cruciate Ligament Injuries.
Browse Anterior Cruciate Ligament Injuries studies →Austrian Workers Compensation Board Styria is the lead sponsor of 2 studies on the registry; 2 are open to participants now.
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Exclusion Criteria:
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biocomposite Interference Screw Fixation of the Tibial End of the Graft
Procedure: ACL Reconstruction with a Biocomposite Screw
Polyether Ether Ketone Interference Screw Fixation of the Tibial End of the Graft
Procedure: ACL Reconstruction using a PEEK Screw
Allograft Bone Interference Screw Fixation of the Tibial End of the Graft
Procedure: ACL Reconstruction using an Allograft Screw
ACL Reconstruction using a standardized technique. Tibial Fixation using a Biocomposite Screw.
ACL Reconstruction using a standardized technique. Tibial Fixation using a PEEK Screw.
ACL Reconstruction using a standardized technique. Tibial Fixation using a SharkScrew Allograft Interference Screw.
Tibial Tunnel Widening
CT Measurement of the tibial Tunnel Widening in mm. The difference will be calculated between drilled diameter and measured diameter.
Time frame: 1 Year Postop
MRI Graft Integration
MRI Graft Integration using SNL Coefficient. Baseline PCL graft signal on fat suppressed T2 will be compared to the ACL in 3 zones, tibial, intraarticular and femoral. The technique is described in detail in Putnis SE, Klasan A, Oshima T, Grasso S, Neri T, Coolican MRJ, Fritsch BA, Parker DA. Magnetic Resonance Imaging Assessment of Hamstring Graft Healing and Integration 1 and Minimum 2 Years after ACL Reconstruction. Am J Sports Med. 2022 Jul;50(8):2102-2110. doi: 10.1177/03635465221096672. Epub 2022 May 25. PMID: 35612835.
Time frame: 6 Months and 1 Year
Lysholm
Lysholm Questionnaire scores will be assessed. Possible value 0-100. Higher is better.
Time frame: 1 Year postop
Tegner
Tegner Questionnaire will be assessed. Range 0-10, higher is better.
Time frame: Preop, 1 year postop
ACL-RSI
ACL-RSI Questionnaire will be assessed. 0-100, higher is better.
Time frame: 12 month postop
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Start is estimated for Nov 2026; primary completion for Dec 2028, 25 months later.
Of 278 non-industry interventional studies with no phase under Anterior Cruciate Ligament Injuries, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 14 and three quarters within 70. This study's planned 25 months is below that.
Counting every sponsor, half of 287 studies reached it within 30 months; a quarter within 14 and three quarters within 70.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Anterior Cruciate Ligament Injuries →
Austrian Workers Compensation Board Styria