ACL - Anterior Cruciate Ligament RuptureNCT07830953
SharkScrew ACL RCT
A study testing ACL Reconstruction with a Biocomposite Screw, ACL Reconstruction using a PEEK Screw and ACL Reconstruction using an Allograft Screw in people with ACL - Anterior Cruciate Ligament Rupture, run by Austrian Workers Compensation Board Styria at 1 site in Austria.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- ACL - Anterior Cruciate Ligament Rupture
- What is being tested?
- ACL Reconstruction with a Biocomposite Screw, ACL Reconstruction using a PEEK Screw and ACL Reconstruction using an Allograft Screw
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 33 participants
- Where
- 1 siteAustria
- Study dates
- 1 Nov 2026to 31 Dec 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male and non-pregnant female patients aged 18-70 years
- MRI-confirmed rupture of the anterior cruciate ligament (ACL)
- Clinically positive anterior drawer test and Lachman test
- Subjective instability
- Clinically and MRI-confirmed intact posterior cruciate ligament (PCL), medial collateral ligament (MCL), and posterolateral corner
- Written informed consent obtained
- Patient is able and willing to participate in the study
Who cannot join
- Previous surgery on the affected knee joint (ACL reconstruction, fracture fixation, osteotomy, or partial joint replacement)
- Body mass index (BMI) > 40
- Coronal instability due to injury of the medial collateral ligament or posterolateral corner
- Meniscal injury requiring postoperative restriction of weight-bearing (e.g., root tears, radial tears)
- The patient is unable to speak German
- The patient is pregnant
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Austria1 site
AUVA UKH Steiermark, Standort Graz
Graz, Styria, 8044
Antonio Klasan, MD, PhD, EMBA, FRCS, +43 677 61047945, klasan.antonio@me.com
About this study
Official title: Prospective Randomized Controlled Trial of 3 Types of Tibial Intereference Screws for ACL Reconstruction
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.
Read the detailed description
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.
- Conditions
- ACL - Anterior Cruciate Ligament Rupture
- Being tested
- ACL Reconstruction with a Biocomposite Screw, ACL Reconstruction using a PEEK Screw, ACL Reconstruction using an Allograft Screw
- Keywords
- ACL Rupture, ACL Reconstruction
- Medical subject headings
- Anterior Cruciate Ligament Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ACL Reconstruction with a Biocomposite ScrewProcedure or surgery
ACL Reconstruction using a standardized technique. Tibial Fixation using a Biocomposite Screw.
ACL Reconstruction using a PEEK ScrewProcedure or surgery
ACL Reconstruction using a standardized technique. Tibial Fixation using a PEEK Screw.
ACL Reconstruction using an Allograft ScrewProcedure or surgery
ACL Reconstruction using a standardized technique. Tibial Fixation using a SharkScrew Allograft Interference Screw.
| Study group | Role | What they receive |
|---|---|---|
| Biocomposite Interference Screw | Active comparator | Biocomposite Interference Screw Fixation of the Tibial End of the Graft Receives: Procedure: ACL Reconstruction with a Biocomposite Screw |
| PEEK Interference Screw | Active comparator | Polyether Ether Ketone Interference Screw Fixation of the Tibial End of the Graft Receives: Procedure: ACL Reconstruction using a PEEK Screw |
| Shark Screw | Experimental | Allograft Bone Interference Screw Fixation of the Tibial End of the Graft Receives: Procedure: ACL Reconstruction using an Allograft Screw |
What is being measured
The primary outcome is the main question the study is designed to answer.
Tibial Tunnel Widening
CT Measurement of the tibial Tunnel Widening in mm. The difference will be calculated between drilled diameter and measured diameter.
Measured: 1 Year Postop
Secondary outcomes (4)
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.
Measured: 6 Months and 1 Year
Lysholm
Lysholm Questionnaire scores will be assessed. Possible value 0-100. Higher is better.
Measured: 1 Year postop
Tegner
Tegner Questionnaire will be assessed. Range 0-10, higher is better.
Measured: Preop, 1 year postop
ACL-RSI
ACL-RSI Questionnaire will be assessed. 0-100, higher is better.
Measured: 12 month postop
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2026
- Study start1 Nov 2026 (estimated)
- Primary completion31 Dec 2028 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ACL - Anterior Cruciate Ligament RuptureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 33 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Austrian Workers Compensation Board Styria
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07830953
- Sponsor's protocol ID
- SharkACL
- Status last verified
- Sep 2026
- First submitted
- 18 Jul 2026
- Last updated
- 5 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 5 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prospective Randomized Controlled Trial of 3 Types of Tibial Intereference Screws for ACL Reconstruction
- ClinicalTrials.gov ID
- NCT07830953
- Acronym / sponsor ID
- SharkACL
- Conditions
- ACL - Anterior Cruciate Ligament Rupture
- Keywords
- ACL Rupture, ACL Reconstruction
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 33 participants (estimated)
- Lead sponsor
- Austrian Workers Compensation Board StyriaUniversity, hospital or other
- Study start
- 1 Nov 2026 (estimated)
- Primary completion
- 31 Dec 2028 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 21 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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:
---
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Biocomposite Interference Screw | Active comparator | Procedure: ACL Reconstruction with a Biocomposite ScrewBiocomposite Interference Screw Fixation of the Tibial End of the Graft |
| PEEK Interference Screw | Active comparator | Procedure: ACL Reconstruction using a PEEK ScrewPolyether Ether Ketone Interference Screw Fixation of the Tibial End of the Graft |
| Shark Screw | Experimental | Procedure: ACL Reconstruction using an Allograft ScrewAllograft Bone Interference Screw Fixation of the Tibial End of the Graft |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Male and non-pregnant female patients aged 18-70 years
- MRI-confirmed rupture of the anterior cruciate ligament (ACL)
- Clinically positive anterior drawer test and Lachman test
- Subjective instability
- Clinically and MRI-confirmed intact posterior cruciate ligament (PCL), medial collateral ligament (MCL), and posterolateral corner
Key exclusion criteria (6 listed)
- Previous surgery on the affected knee joint (ACL reconstruction, fracture fixation, osteotomy, or partial joint replacement)
- Body mass index (BMI) > 40
- Coronal instability due to injury of the medial collateral ligament or posterolateral corner
- Meniscal injury requiring postoperative restriction of weight-bearing (e.g., root tears, radial tears)
- The patient is unable to speak German
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ACL Reconstruction with a Biocomposite ScrewACL Reconstruction using a standardized technique. Tibial Fixation using a Biocomposite Screw. | Procedure or surgery | Biocomposite Interference Screw |
| ACL Reconstruction using a PEEK ScrewACL Reconstruction using a standardized technique. Tibial Fixation using a PEEK Screw. | Procedure or surgery | PEEK Interference Screw |
| ACL Reconstruction using an Allograft ScrewACL Reconstruction using a standardized technique. Tibial Fixation using a SharkScrew Allograft Interference Screw. | Procedure or surgery | Shark Screw |
Primary outcome
Tibial Tunnel Widening
Time frame: 1 Year Postop
CT Measurement of the tibial Tunnel Widening in mm. The difference will be calculated between drilled diameter and measured diameter.
4 secondary outcomes
MRI Graft Integration
Time frame: 6 Months and 1 Year
Lysholm
Time frame: 1 Year postop
Tegner
Time frame: Preop, 1 year postop
ACL-RSI
Time frame: 12 month postop
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing ACL Reconstruction with a Biocomposite Screw, ACL Reconstruction using a PEEK Screw and ACL Reconstruction using an Allograft Screw in people with ACL - Anterior Cruciate Ligament Rupture, run by Austrian Workers Compensation Board Styria at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 5 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Antonio Klasan, MD, PhD, EMBA, FRCS (+43 676 5085920, klasan.antonio@me.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Tibial Tunnel Widening (time frame: 1 Year Postop). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Oct 2026.