Knee InjuriesNCT02918734
Fixation of Patellar Tendon Grafts in Anterior Cruciate Ligament Reconstruction. Endobutton vs Metal Interference Screws
A study testing Endobutton CL BTB and Metal interference screw in people with Knee Injuries, run by St. Olavs Hospital at 2 sites in Norway.
Trial summary
In this randomized controlled trial the investigators will compare the results after primary anterior cruciate ligament (ACL) reconstruction using two different methods for femoral fixation of a bone-patellar tendon-bone (BPTB) autograft. Read more about this study
- Who is it for?
- Ages 18 to 55 years
- Conditions the study is for
- Knee Injuries
- What is being tested?
- Endobutton CL BTB and Metal interference screw
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 220 participants
- Where
- 2 sitesNorway
- Study dates
- Oct 2016to Mar 2033
- 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 55 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Primary reconstruction of ACL ruptures
- Surgery at least 6 weeks after injury
- The patient must accept and sign the informed consent form before surgery
Who cannot join
- Medical indication for using another graft than BPTB autograft (such as history of anterior knee pain or occupations etc. requiring frequent kneeling)
- Previous major surgical procedures in the same knee
- Major additional injuries in the knee (posterior cruciate ligament, lateral collateral ligament, medial collateral ligament, sutured meniscus lesions and major cartilage lesions undergoing cartilage repair)
- Contralateral ACL injury (treated or untreated)
- Present or former serious illness that makes follow-up or rehabilitation difficult (e.g. alcohol or drug abuse, psychiatric disease)
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Trond Olav Lundemo, md contact
Tone Gifstad, md phd contact
Norway2 sites, 2 recruiting
- Recruiting
Department of Orthopedic Surgery, St Olavs Hospital
Trondheim
- Recruiting
Rosenborgklinikken
Trondheim
Agnar Tegnander, md phd
About this study
Official title: A Prospective Randomized Controlled Trial Comparing the Endobutton CL BTB Fixation System With Metal Interference Screws in the Femoral Fixation of Patellar Tendon Grafts in Anterior Cruciate Ligament Reconstruction.
In this randomized controlled trial the investigators will compare the results after primary anterior cruciate ligament (ACL) reconstruction using two different methods for femoral fixation of a bone-patellar tendon-bone (BPTB) autograft. Interference screws have been the standard method for fixing the femoral side of BPTB grafts; however, several pitfalls have been reported. Cortical fixation with the Endobutton CL BTB Fixation System has become available and the clinical results have been described as promising; however, no randomized controlled trials comparing these two femoral fixation methods have been conducted, and there is no published data that confirms that the bone block heals in the tunnel with the newer method.
The aim of our study is to compare the outcome after primary ACL reconstruction with BPTB autografts using the Endobutton CL BTB or metal interference screw for femoral fixation.
Read the detailed description
Primary anterior cruciate ligament (ACL) reconstructions with bone-patellar tendon-bone (BPTB) autografts have recently been found to have a lower risk of revision compared with hamstring tendon autografts, and BPTB has again become our graft of choice. Interference screws have been the standard method for fixing the femoral side of a BPTB graft; however problems such as damage of the graft and failure due to nonparallel screw placement have been reported. Cortical fixation using a suspensory system has been used for soft-tissue graft fixation for several years, and a corresponding device, the Endobutton CL BTB Fixation System (Smith \& Nephew, Inc., Andover, MA, USA), has become available for fixation of bone-tendon-bone grafts. The clinical results after fixation with the Endobutton CL BTB have been described as promising; however, no randomized controlled trials comparing these two fixation methods have been conducted, and there is no published data that confirms that the bone block heals in the tunnel with the newer method.
In this randomized controlled trial, patients undergoing primary ACL reconstruction will be randomized into either an Endobutton group or an interference screw group. The primary aim of the study is to compare these two fixation methods, assessed by patient reported outcomes, laxity, range of motion and muscle strength. Knee related quality of life 2 years after surgery is the primary outcome, measured by the Knee injury and Osteoarthritis Outcome Score (KOOS) subscale "knee related Quality of life (QOL)". Other aims are to see if there is any difference in the integration of the bone block in the femoral tunnel assessed by CT scan, in the risk of developing osteoarthritis assessed by radiographs, or in the risk of a postoperative complication or revision. The patients will be followed up 6 weeks, 6 months, 2 years and 10 years after surgery. CT scan will be performed after 6 months, and radiographs after 2 years and 10 years. In addition details of the rehabilitation will be recorded. Patients undergoing a revision will be followed up but excluded from further comparisons in the study.
Our hypothesis is that there is no difference in the outcome after primary ACL reconstruction with BPTB autografts using the Endobutton CL BTB or metal interference screw for femoral fixation, both with a metal interference screw for the tibial fixation.
- Conditions
- Knee Injuries
- Being tested
- Endobutton CL BTB, Metal interference screw
- Keywords
- Anterior Cruciate Ligament, Bone-Patellar Tendon-Bone Grafting
- Medical subject headings
- Knee Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Endobutton CL BTBDevice
ACL reconstruction with Endobutton CL BTB
Metal interference screwDevice
ACL reconstruction with metal interference screw
| Study group | Role | What they receive |
|---|---|---|
| Endobutton CL BTB | Experimental | Femoral fixation of the BPTB autograft with the Endobutton CL BTB Fixation System. Receives: Device: Endobutton CL BTB |
| Metal interference screw | Active comparator | Femoral fixation of the BPTB autograft with a metal interference screw. Receives: Device: Metal interference screw |
What is being measured
The primary outcome is the main question the study is designed to answer.
Knee related quality of life
KOOS subscale "knee related Quality of life (QOL)"
Measured: 2 years
Secondary outcomes (13)
Tegner activity scale
Measured: 6 months, 2 years, 10 years
Lachman test
Anterior translation of the tibia
Measured: 6 weeks, 6 months, 2 years, 10 years
Muscular strength
Biodex dynamometer
Measured: 6 months, 2 years, 10 years
Bone block integration
CT scan
Measured: 6 months
Osteoarthritis
X-ray radiographs
Measured: 2 years, 10 years
Range of motion
Measured: 6 weeks, 6 months, 2 years, 10 years
Knee related quality of life
KOOS subscale "knee related Quality of life (QOL)"
Measured: 6 weeks
Knee related quality of life
KOOS subscale "knee related Quality of life (QOL)"
Measured: 6 months
Knee related quality of life
KOOS subscale "knee related Quality of life (QOL)"
Measured: 10 years
Lysholm functional knee score
Measured: 6 weeks, 6 months, 2 years, 10 years
KOOS
Knee injury and Osteoarthritis Outcome Score
Measured: 6 weeks, 6 months, 2 years, 10 years
Pivot shift test
Anteroposterior and rotational stability
Measured: 6 weeks, 6 months, 2 years, 10 years
KT-1000 arthrometer
Anterior translation of the tibia
Measured: 6 weeks, 6 months, 2 years, 10 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Sep 2016 (estimated)
- Study startOct 2016
- Primary completionDec 2026 (estimated)
- Study completionMar 2033 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Knee InjuriesStudies of the same condition, open and under way.
- More trials run by St. Olavs HospitalThe sponsor's other registered studies.
- 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
- Single blind
- Who is masked
- Participant
- Enrolment
- 220 participants (estimated)
Sponsor and investigators
- Lead sponsor
- St. Olavs Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Rosenborgklinikken
- Responsible party
- Sponsor
- Investigators
- Jon Olav Drogset, md phd, Principal investigator, St. Olavs Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02918734
- Sponsor's protocol ID
- 2015/993
- Status last verified
- Jul 2026
- First submitted
- 20 Jun 2016
- Last updated
- 20 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Randomized Controlled Trial Comparing the Endobutton CL BTB Fixation System With Metal Interference Screws in the Femoral Fixation of Patellar Tendon Grafts in Anterior Cruciate Ligament Reconstruction.
- ClinicalTrials.gov ID
- NCT02918734
- Acronym / sponsor ID
- 2015/993
- Conditions
- Knee Injuries
- Keywords
- Anterior Cruciate Ligament, Bone-Patellar Tendon-Bone Grafting
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 220 participants (estimated)
- Lead sponsor
- St. Olavs HospitalUniversity, hospital or other
- Collaborators
- Rosenborgklinikken
- Study start
- Oct 2016 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Mar 2033 (estimated)
- First posted
- 29 Sep 2016 (estimated)
- 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.
In this randomized controlled trial the investigators will compare the results after primary anterior cruciate ligament (ACL) reconstruction using two different methods for femoral fixation of a bone-patellar tendon-bone (BPTB) autograft. Interference screws have been the standard method for fixing the femoral side of BPTB grafts; however, several pitfalls have been reported. Cortical fixation with the Endobutton CL BTB Fixation System has become available and the clinical results have been described as promising; however, no randomized controlled trials comparing these two femoral fixation methods have been conducted, and there is no published data that confirms that the bone block heals in the tunnel with the newer method.
The aim of our study is to compare the outcome after primary ACL reconstruction with BPTB autografts using the Endobutton CL BTB or metal interference screw for femoral fixation.
Detailed description
Primary anterior cruciate ligament (ACL) reconstructions with bone-patellar tendon-bone (BPTB) autografts have recently been found to have a lower risk of revision compared with hamstring tendon autografts, and BPTB has again become our graft of choice. Interference screws have been the standard method for fixing the femoral side of a BPTB graft; however problems such as damage of the graft and failure due to nonparallel screw placement have been reported. Cortical fixation using a suspensory system has been used for soft-tissue graft fixation for several years, and a corresponding device, the Endobutton CL BTB Fixation System (Smith \& Nephew, Inc., Andover, MA, USA), has become available for fixation of bone-tendon-bone grafts. The clinical results after fixation with the Endobutton CL BTB have been described as promising; however, no randomized controlled trials comparing these two fixation methods have been conducted, and there is no published data that confirms that the bone block heals in the tunnel with the newer method.
In this randomized controlled trial, patients undergoing primary ACL reconstruction will be randomized into either an Endobutton group or an interference screw group. The primary aim of the study is to compare these two fixation methods, assessed by patient reported outcomes, laxity, range of motion and muscle strength. Knee related quality of life 2 years after surgery is the primary outcome, measured by the Knee injury and Osteoarthritis Outcome Score (KOOS) subscale "knee related Quality of life (QOL)". Other aims are to see if there is any difference in the integration of the bone block in the femoral tunnel assessed by CT scan, in the risk of developing osteoarthritis assessed by radiographs, or in the risk of a postoperative complication or revision. The patients will be followed up 6 weeks, 6 months, 2 years and 10 years after surgery. CT scan will be performed after 6 months, and radiographs after 2 years and 10 years. In addition details of the rehabilitation will be recorded. Patients undergoing a revision will be followed up but excluded from further comparisons in the study.
Our hypothesis is that there is no difference in the outcome after primary ACL reconstruction with BPTB autografts using the Endobutton CL BTB or metal interference screw for femoral fixation, both with a metal interference screw for the tibial fixation.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Endobutton CL BTB | Experimental | Device: Endobutton CL BTBFemoral fixation of the BPTB autograft with the Endobutton CL BTB Fixation System. |
| Metal interference screw | Active comparator | Device: Metal interference screwFemoral fixation of the BPTB autograft with a metal interference screw. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Primary reconstruction of ACL ruptures
- Surgery at least 6 weeks after injury
- The patient must accept and sign the informed consent form before surgery
Key exclusion criteria (5 listed)
- Medical indication for using another graft than BPTB autograft (such as history of anterior knee pain or occupations etc. requiring frequent kneeling)
- Previous major surgical procedures in the same knee
- Major additional injuries in the knee (posterior cruciate ligament, lateral collateral ligament, medial collateral ligament, sutured meniscus lesions and major cartilage lesions undergoing cartilage repair)
- Contralateral ACL injury (treated or untreated)
- Present or former serious illness that makes follow-up or rehabilitation difficult (e.g. alcohol or drug abuse, psychiatric disease)
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 |
|---|---|---|
| Endobutton CL BTBACL reconstruction with Endobutton CL BTB | Device | Endobutton CL BTB |
| Metal interference screwACL reconstruction with metal interference screw | Device | Metal interference screw |
Primary outcome
Knee related quality of life
Time frame: 2 years
KOOS subscale "knee related Quality of life (QOL)"
13 secondary outcomes
Tegner activity scale
Time frame: 6 months, 2 years, 10 years
Lachman test
Time frame: 6 weeks, 6 months, 2 years, 10 years
Muscular strength
Time frame: 6 months, 2 years, 10 years
Bone block integration
Time frame: 6 months
Osteoarthritis
Time frame: 2 years, 10 years
Range of motion
Time frame: 6 weeks, 6 months, 2 years, 10 years
Knee related quality of life
Time frame: 6 weeks
Knee related quality of life
Time frame: 6 months
Knee related quality of life
Time frame: 10 years
Lysholm functional knee score
Time frame: 6 weeks, 6 months, 2 years, 10 years
KOOS
Time frame: 6 weeks, 6 months, 2 years, 10 years
Pivot shift test
Time frame: 6 weeks, 6 months, 2 years, 10 years
KT-1000 arthrometer
Time frame: 6 weeks, 6 months, 2 years, 10 years
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 20 Jul 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.
Trond Olav Lundemo, md contact
Tone Gifstad, md phd contact
Jon Olav Drogset, md phd principal investigator
St. Olavs Hospital
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Endobutton CL BTB and Metal interference screw in people with Knee Injuries, run by St. Olavs Hospital at 2 sites in Norway.
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 3 inclusion and 5 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: looking for participants now, as of the sponsor's last update on 20 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Norway. 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 Trond Olav Lundemo, md (TrondOlav.Lundemo@helse-nordtrondelag.no), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Knee related quality of life (time frame: 2 years). 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 20 Jul 2026; AzTrials last refreshed its copy on 8 Nov 2026.