Anterior Cruciate Ligament InjuryNACOXNCT02931084
Natural Course and Recovery After ACL-injury
An observational study of Anterior Cruciate Ligament Injury, run by Linkoeping University at 1 site in Sweden.
Trial summary
The natural course after ACL injury is not well described in the literature. Every year about 7000 people, a majority aged 15-30 years old, injure their anterior cruciate ligament (ACL) in Sweden. About 3500 go through surgical treatment and rehabilitation. Read more about this study
- Who is it for?
- Ages 15 to 40 years
- Conditions the study is for
- Anterior Cruciate Ligament Injury
- What is being tested?
- Rehabilitation and ACL reconstruction
- Type of treatment
- Surgery or procedure
- How many people
- 275 participants
- Where
- 1 siteSweden
- Study dates
- Oct 2016to Dec 2025
- How long will I take part?
- 5 Years
- Phase
- Observational
- Are there results?
- None posted in the registry
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 15 to 40 years
- All sexes
- No healthy volunteers
- Child, Adult
Study population: Patients with ACL-injury from 7 different sites in Sweden
Who may be able to join
- Patients with a knee injury (ACL injury)
- Age at time of ACL injury: 15-40 years
Who cannot join
- ACL injury/ACL reconstruction on the same knee
- Serious knee injuries to the injured knee, ex fracture that require separate treatment
- ACL injury more than 6 weeks ago
- Inability to understand written and spoken Swedish language
- Cognitive impairments
- Other illness/injury that impairs function (e.g. fibromyalgia, rheumatic diseases and other diagnosis that causes chronic pain)
Trial locations and contacts
1 site in 1 country.
About this study
The natural course after ACL injury is not well described in the literature. Every year about 7000 people, a majority aged 15-30 years old, injure their anterior cruciate ligament (ACL) in Sweden. About 3500 go through surgical treatment and rehabilitation. Despite the large amount of research on ACL-injuries, there are still many patients who have unsatisfactory outcomes regarding instability, decreased activity level, and quality of life, not being able to return to sport as well as an increased risk for osteoarthritis. The general aim of the study is to evaluate the natural course and recovery after ACL injury. Specific aims:
- To evaluate physical, psychological and contextual factors affecting recovery after anterior cruciate ligament (ACL) injury. Recovery is related both to natural course and to treatment chosen
- To evaluate factors affecting the decision for which treatment to choose (ACL reconstruction and rehabilitation or rehabilitation alone)
- To evaluate factors affecting the decision for return to sports
- To study development of knee osteoarthritis after ACL-injury
- To study epidemiology of acute knee trauma
- To study risk factors for new injuries after ACL-injury These aims will be pursued by consequently and prospectively following patients who sustain a new ACL injury in a multicenter study including approximately 800 patients. Assessment methods will be questionnaires to patients, orthopedic doctors and physical therapists. A sub-cohort of 130 patients will undergo multiple clinical and functional examination as well as MRIs and blood, urine and joint fluid samples.
Read the detailed description
Study design: A descriptive and prospective prognostic cohort study, with consecutive recruitment of patients during a 12 month period from seven sites in Sweden Start of recruiting participants is October 2016. Most participants will receive a diagnosis from an orthopedic doctor approximately 2-4 weeks after their knee injury, and undergo rehabilitation for at least the first three months, before a decision regarding ACL reconstruction is taken (in line with current treatment guidelines). The patient cohort will be naturally divided into reconstruction plus rehabilitation, and rehabilitation only. Being included in the study will not affect the choice of treatment.
Patients will be asked to participate at their initial contact with healthcare, after their knee injury. The recruitment process will differ slightly between the different sites, based on the clinical routine.
Patients who accept to participate will complete web-based questionnaires distributed via smart phones or e-mail, once a week the first 6 weeks, every second week up to 3rd month, every month up to 1 year and every second month up to 3 years after initial injury. The length of the questionnaires varies from very short (approximately 10 questions that take 2 minutes to fill in) to longer at specific critical time points. Each time the patient has contact with an orthopedic surgeon, the patient, orthopedic doctor and physiotherapist (if the patient has contact with one) will be asked to answer a questionnaire about choice of treatment (surgery or not). In addition, when the patient reports that they are back to sport activity, the patient and the physiotherapist will be asked to answer a questionnaire about the decision to return to sport. Patients who will have ACL reconstruction will be followed up with new baseline from the time of reconstruction.
Patients recruited from Linköping will have expanded follow-up data collection at baseline and 3, 6, 12 and 24 months after injury. At these follow-ups, a clinical examination will be completed by an orthopedic surgeon or physiotherapist, MRI, and blood and urine samples will be collected. A joint fluid sample will be acquired at baseline, and at the time of ACL reconstruction (if the patient has surgical treatment). Radiographs will be done at baseline and 5 years follow up. Patients who have ACL reconstruction will be followed up with new baseline at the time for reconstruction, but without MRI or blood and urine samples.
- Conditions
- Anterior Cruciate Ligament Injury
- Being tested
- Rehabilitation, 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.
RehabilitationOther
In line with current treatment guidelines, patients will undergo rehabilitation for at least the first three months, before a decision regarding ACL reconstruction is taken
ACL reconstructionProcedure or surgery
Approximately half of the patients will have ACL-reconstruction after an initial time of rehabilitation
| Study group | Role | What they receive |
|---|---|---|
| ACL injury | Patients with an acute (not more than 6 weeks old) anterior cruciate ligament (ACL) injury Receives: Other: Rehabilitation | |
| ACL reconstruction | Some of the patients with ACL injury will have reconstruction of the ACL. These will be followed as a new group. Receives: Other: Rehabilitation; Procedure: ACL reconstruction |
What is being measured
The primary outcome is the main question the study is designed to answer.
Return to physical activity/ sports
Patients report when they are back to unrestricted physical activity or sports
Measured: 1 year
Knee function, IKDC
The IKDC subjective knee evaluation form is a self-administered questionnaire which contains 18 items divided into 3 subgroups. These subgroups are symptoms, sports and daily activities and the patients current and previous levels of knee function.
Measured: 1 year
Osteoarthritis
Development of osteoarthritis examined with x-rays at 5 years
Measured: 5 years
New injuries
Reported new knee injuries
Measured: 3 years
Factors related to treatment choice
Questionnaires to patients, orthopedic surgeon and physical therapist about the treatment decision
Measured: 1 year
Secondary outcomes (7)
Psychological factors affecting recovery
Include questionnaires about motivation, goals, satisfaction, self efficacy, fear for new injury, readiness for return to sports, expectations
Measured: 2 years
Physical factors affecting recovery, Range of motion
Measured with goniometer
Measured: 1 year
IKDC
The IKDC subjective knee evaluation form is a self-administered questionnaire which contains 18 items divided into 3 subgroups. These subgroups are symptoms, sports and daily activities and the patients current and previous levels of knee function.
Measured: 2 years
Physical factors affecting recovery, gait
Qualitativ assessment of gait pattern
Measured: 4 weeks
Physical factors affecting recovery, muscle strength
Measured with the Biodex dynamometer, peak torque at 60 degrees per second
Measured: 6 months
Physical factors affecting recovery, functional performance
Measured with hop tests, evaluated with the LSI (limb symmetry index)
Measured: 6 months
Physical factors affecting recovery, functional performance
Measured with hop tests, evaluated with the LSI (limb symmetry index)
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Oct 2016 (estimated)
- Study startOct 2016
- Primary completionOct 2025 (estimated)
- Study completionDec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for Anterior Cruciate Ligament InjuryStudies of the same condition, open and under way.
- More trials run by Linkoeping UniversityThe 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 275 participants (actual)
- Target duration
- 5 Years
Sponsor and investigators
- Lead sponsor
- Linkoeping University
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Joanna Kvist, Linkoeping University
- Investigators
- Joanna Kvist, Professor, Principal investigator, IMH Linkoping University, Sweden
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02931084
- Sponsor's protocol ID
- NACOX
- Acronym
- NACOX
- Status last verified
- Nov 2023
- First submitted
- 9 Oct 2016
- Last updated
- 30 Nov 2023
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- No
Publications
Kvist J, Liu A, Giannotti N, Filbay S, Hedevik H, Stalman A, Frobell R, Gauffin H, Englund M. Structural Changes of the Anterior Cruciate Ligament (ACL), Evaluated by MRI, and Their Relation to Clinical Outcomes, Within 2 Years After ACL Injury. Results From the NACOX Cohort Study. J Orthop Sports Phys Ther. 2026 Mar;56(3):209-219. doi: 10.2519/jospt.2026.13397.
PubMed 41764172Sonesson S, Kuster RP, Kvist J. Accelerometer-assessed physical activity patterns during the first two years after a non-surgically treated ACL injury. Phys Ther Sport. 2023 Nov;64:123-132. doi: 10.1016/j.ptsp.2023.09.011. Epub 2023 Oct 12.
PubMed 37864852Sonesson S, Kvist J. Bilateral changes in knee joint laxity during the first year after non-surgically treated anterior cruciate ligament injury. Phys Ther Sport. 2022 Nov;58:173-181. doi: 10.1016/j.ptsp.2022.10.011. Epub 2022 Oct 26.
PubMed 36368151Casula V, Tajik BE, Kvist J, Frobell R, Haapea M, Nieminen MT, Gauffin H, Englund M. Quantitative evaluation of the tibiofemoral joint cartilage by T2 mapping in patients with acute anterior cruciate ligament injury vs contralateral knees: results from the subacute phase using data from the NACOX study cohort. Osteoarthritis Cartilage. 2022 Jul;30(7):987-997. doi: 10.1016/j.joca.2022.02.623. Epub 2022 Apr 11.
PubMed 35421548Filbay S, Kvist J. Fear of Reinjury Following Surgical and Nonsurgical Management of Anterior Cruciate Ligament Injury: An Exploratory Analysis of the NACOX Multicenter Longitudinal Cohort Study. Phys Ther. 2022 Feb 1;102(2):pzab273. doi: 10.1093/ptj/pzab273.
PubMed 34939109Grevnerts HT, Sonesson S, Gauffin H, Ardern CL, Stalman A, Kvist J. Decision Making for Treatment After ACL Injury From an Orthopaedic Surgeon and Patient Perspective: Results From the NACOX Study. Orthop J Sports Med. 2021 Apr 15;9(4):23259671211005090. doi: 10.1177/23259671211005090. eCollection 2021 Apr.
PubMed 33948447Kvist J, Gauffin H, Tigerstrand Grevnerts H, Ardern C, Hagglund M, Stalman A, Frobell R. Natural corollaries and recovery after acute ACL injury: the NACOX cohort study protocol. BMJ Open. 2018 Jun 27;8(6):e020543. doi: 10.1136/bmjopen-2017-020543.
PubMed 29950463
Study at a glance
From the registry record, last updated by the sponsor on 30 Nov 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Natural Course and Recovery After ACL-injury
- ClinicalTrials.gov ID
- NCT02931084
- Acronym / sponsor ID
- NACOX / NACOX
- Conditions
- Anterior Cruciate Ligament Injury
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 275 participants (actual)
- Lead sponsor
- Linkoeping UniversityOther government
- Study start
- Oct 2016 (actual)
- Primary completion
- Oct 2025 (estimated)
- Study completion
- Dec 2025 (estimated)
- First posted
- 12 Oct 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.
The natural course after ACL injury is not well described in the literature. Every year about 7000 people, a majority aged 15-30 years old, injure their anterior cruciate ligament (ACL) in Sweden. About 3500 go through surgical treatment and rehabilitation. Despite the large amount of research on ACL-injuries, there are still many patients who have unsatisfactory outcomes regarding instability, decreased activity level, and quality of life, not being able to return to sport as well as an increased risk for osteoarthritis. The general aim of the study is to evaluate the natural course and recovery after ACL injury. Specific aims:
- To evaluate physical, psychological and contextual factors affecting recovery after anterior cruciate ligament (ACL) injury. Recovery is related both to natural course and to treatment chosen
- To evaluate factors affecting the decision for which treatment to choose (ACL reconstruction and rehabilitation or rehabilitation alone)
- To evaluate factors affecting the decision for return to sports
- To study development of knee osteoarthritis after ACL-injury
- To study epidemiology of acute knee trauma
- To study risk factors for new injuries after ACL-injury These aims will be pursued by consequently and prospectively following patients who sustain a new ACL injury in a multicenter study including approximately 800 patients. Assessment methods will be questionnaires to patients, orthopedic doctors and physical therapists. A sub-cohort of 130 patients will undergo multiple clinical and functional examination as well as MRIs and blood, urine and joint fluid samples.
Detailed description
Study design: A descriptive and prospective prognostic cohort study, with consecutive recruitment of patients during a 12 month period from seven sites in Sweden Start of recruiting participants is October 2016. Most participants will receive a diagnosis from an orthopedic doctor approximately 2-4 weeks after their knee injury, and undergo rehabilitation for at least the first three months, before a decision regarding ACL reconstruction is taken (in line with current treatment guidelines). The patient cohort will be naturally divided into reconstruction plus rehabilitation, and rehabilitation only. Being included in the study will not affect the choice of treatment.
Patients will be asked to participate at their initial contact with healthcare, after their knee injury. The recruitment process will differ slightly between the different sites, based on the clinical routine.
Patients who accept to participate will complete web-based questionnaires distributed via smart phones or e-mail, once a week the first 6 weeks, every second week up to 3rd month, every month up to 1 year and every second month up to 3 years after initial injury. The length of the questionnaires varies from very short (approximately 10 questions that take 2 minutes to fill in) to longer at specific critical time points. Each time the patient has contact with an orthopedic surgeon, the patient, orthopedic doctor and physiotherapist (if the patient has contact with one) will be asked to answer a questionnaire about choice of treatment (surgery or not). In addition, when the patient reports that they are back to sport activity, the patient and the physiotherapist will be asked to answer a questionnaire about the decision to return to sport. Patients who will have ACL reconstruction will be followed up with new baseline from the time of reconstruction.
Patients recruited from Linköping will have expanded follow-up data collection at baseline and 3, 6, 12 and 24 months after injury. At these follow-ups, a clinical examination will be completed by an orthopedic surgeon or physiotherapist, MRI, and blood and urine samples will be collected. A joint fluid sample will be acquired at baseline, and at the time of ACL reconstruction (if the patient has surgical treatment). Radiographs will be done at baseline and 5 years follow up. Patients who have ACL reconstruction will be followed up with new baseline at the time for reconstruction, but without MRI or blood and urine samples.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 5 Years
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| ACL injury | – | Other: RehabilitationPatients with an acute (not more than 6 weeks old) anterior cruciate ligament (ACL) injury |
| ACL reconstruction | – | Other: Rehabilitation, Procedure: ACL reconstructionSome of the patients with ACL injury will have reconstruction of the ACL. These will be followed as a new group. |
Who may qualify
- Ages
- 15 to 40 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
- Study population
- Patients with ACL-injury from 7 different sites in Sweden
Key inclusion criteria (2 listed)
- Patients with a knee injury (ACL injury)
- Age at time of ACL injury: 15-40 years
Key exclusion criteria (6 listed)
- ACL injury/ACL reconstruction on the same knee
- Serious knee injuries to the injured knee, ex fracture that require separate treatment
- ACL injury more than 6 weeks ago
- Inability to understand written and spoken Swedish language
- Cognitive impairments
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 |
|---|---|---|
| RehabilitationIn line with current treatment guidelines, patients will undergo rehabilitation for at least the first three months, before a decision regarding ACL reconstruction is taken | Other | ACL injury, ACL reconstruction |
| ACL reconstructionApproximately half of the patients will have ACL-reconstruction after an initial time of rehabilitation | Procedure or surgery | ACL reconstruction |
Primary outcome
Return to physical activity/ sports
Time frame: 1 year
Patients report when they are back to unrestricted physical activity or sports
Knee function, IKDC
Time frame: 1 year
The IKDC subjective knee evaluation form is a self-administered questionnaire which contains 18 items divided into 3 subgroups. These subgroups are symptoms, sports and daily activities and the patients current and previous levels of knee function.
Osteoarthritis
Time frame: 5 years
Development of osteoarthritis examined with x-rays at 5 years
New injuries
Time frame: 3 years
Reported new knee injuries
Factors related to treatment choice
Time frame: 1 year
Questionnaires to patients, orthopedic surgeon and physical therapist about the treatment decision
7 secondary outcomes
Psychological factors affecting recovery
Time frame: 2 years
Physical factors affecting recovery, Range of motion
Time frame: 1 year
IKDC
Time frame: 2 years
Physical factors affecting recovery, gait
Time frame: 4 weeks
Physical factors affecting recovery, muscle strength
Time frame: 6 months
Physical factors affecting recovery, functional performance
Time frame: 6 months
Physical factors affecting recovery, functional performance
Time frame: 1 year
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Nov 2023.
- Derived from this study: PubMed 41764172Kvist J, Liu A, Giannotti N, Filbay S, Hedevik H, Stalman A, Frobell R, Gauffin H, Englund M. Structural Changes of the Anterior Cruciate Ligament (ACL), Evaluated by MRI, and Their Relation to Clinical Outcomes, Within 2 Years After ACL Injury. Results From the NACOX Cohort Study. J Orthop Sports Phys Ther. 2026 Mar;56(3):209-219. doi: 10.2519/jospt.2026.13397.
- Derived from this study: PubMed 37864852Sonesson S, Kuster RP, Kvist J. Accelerometer-assessed physical activity patterns during the first two years after a non-surgically treated ACL injury. Phys Ther Sport. 2023 Nov;64:123-132. doi: 10.1016/j.ptsp.2023.09.011. Epub 2023 Oct 12.
- Derived from this study: PubMed 36368151Sonesson S, Kvist J. Bilateral changes in knee joint laxity during the first year after non-surgically treated anterior cruciate ligament injury. Phys Ther Sport. 2022 Nov;58:173-181. doi: 10.1016/j.ptsp.2022.10.011. Epub 2022 Oct 26.
- Derived from this study: PubMed 35421548Casula V, Tajik BE, Kvist J, Frobell R, Haapea M, Nieminen MT, Gauffin H, Englund M. Quantitative evaluation of the tibiofemoral joint cartilage by T2 mapping in patients with acute anterior cruciate ligament injury vs contralateral knees: results from the subacute phase using data from the NACOX study cohort. Osteoarthritis Cartilage. 2022 Jul;30(7):987-997. doi: 10.1016/j.joca.2022.02.623. Epub 2022 Apr 11.
- Derived from this study: PubMed 34939109Filbay S, Kvist J. Fear of Reinjury Following Surgical and Nonsurgical Management of Anterior Cruciate Ligament Injury: An Exploratory Analysis of the NACOX Multicenter Longitudinal Cohort Study. Phys Ther. 2022 Feb 1;102(2):pzab273. doi: 10.1093/ptj/pzab273.
- Derived from this study: PubMed 33948447Grevnerts HT, Sonesson S, Gauffin H, Ardern CL, Stalman A, Kvist J. Decision Making for Treatment After ACL Injury From an Orthopaedic Surgeon and Patient Perspective: Results From the NACOX Study. Orthop J Sports Med. 2021 Apr 15;9(4):23259671211005090. doi: 10.1177/23259671211005090. eCollection 2021 Apr.
- Derived from this study: PubMed 29950463Kvist J, Gauffin H, Tigerstrand Grevnerts H, Ardern C, Hagglund M, Stalman A, Frobell R. Natural corollaries and recovery after acute ACL injury: the NACOX cohort study protocol. BMJ Open. 2018 Jun 27;8(6):e020543. doi: 10.1136/bmjopen-2017-020543.
- 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. This study is not recruiting at the moment.
Joanna Kvist, Professor principal investigator
IMH Linkoping University, Sweden
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Anterior Cruciate Ligament Injury, run by Linkoeping University at 1 site in Sweden.
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 2 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: status not confirmed, as of the sponsor's last update on 30 Nov 2023. 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 Sweden. 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?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Return to physical activity/ sports (time frame: 1 year). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02931084, which also lists 7 linked publications.
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 30 Nov 2023.