The Proximal Hamstring Avulsion Clinical Trial - Operative or Nonoperative Treatment (PHACT)
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ClinicalTrials.gov Identifier: NCT03311997 |
Recruitment Status :
Active, not recruiting
First Posted : October 17, 2017
Last Update Posted : November 3, 2022
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Condition or disease | Intervention/treatment | Phase |
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Hamstring Tendon Injury | Procedure: Surgical reattachment of hamstring tendons | Not Applicable |
The treatment of proximal hamstrings avulsions is controversial and patients with this injury will get treatment recommendations based not on scientific evidence but on personal preferences of their surgeon. The literature is totally devoid of studies comparing the two treatment options; non-operative and operative treatment. In Sweden, it is probably more common to treat these injuries nonoperatively. This is in contrast to existing literature that suggests that better outcomes are expected with operative treatment. However, there is a very clear publication bias in the literature. In fact, of the more than 40 published clinical studies, only a handful mentions the results of non-operatively treated injuries.
In a systematic review examining 13 original studies, patient satisfaction ranged from 88% to 100% after surgical treatment. In nine of the studies strength of hamstrings were reported and ranged from 78% to 101% of the uninjured side. However, residual pain is common, ranging from 8 to 61% in a group of 203 patients and in a recent unpublished study the lower extremity functional score were similar in patients treated by either modality. Additionally, serious nerve injuries after surgery have been reported and infection, anchor failure and re-rupture occur. The reoperation rate in a study by Sarimo et al. was 12%.
This study is a prospective, multicentre, preference-tolerant, randomized controlled trial comparing operative to non-operative treatment of proximal hamstrings avulsions. The study will include a concurrent prospective cohort observational study.
The eligible study population will consist of patients with an acute, avulsion of hamstrings tendons diagnosed in a hospital in Sweden, Norway or Finland and subsequently referred to one of the study sites. All patients fulfilling the inclusion and not meeting the exclusion criteria will be asked to participate in the study. After the patient´s enrolment has been confirmed and informed consent is obtained a set of questionnaires is provided for background data on medical history, activity levels and a recall assessment of the pre-injury functional status. When these questionnaires are completed, the patient is randomized.
If the patient is randomized to non-operative treatment an appointment with a physiotherapist follows and the study rehabilitation protocol is explained. If the patient is randomized to surgery, the procedure is scheduled at the earliest convenient time but no later than 2 weeks from inclusion. The surgical procedure and rehabilitation protocol is standardized among sites. The same rehabilitation protocol is used for both treatment groups.
Participation in this study will last 24 months. In-person participant follow-up visits will occur at enrollment (baseline), at-surgery, 3 months, 6 months, 12 months and 24 months post-surgery. Data for outcomes and radiographs will be collected at follow-up visit.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 120 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Single (Outcomes Assessor) |
Masking Description: | Personell assessing functional performance of patients are blinded. |
Primary Purpose: | Treatment |
Official Title: | The Proximal Hamstring Avulsion Clinical Trial - Nonoperative Treatment Compared With Suture Anchor Reinsertion of Proximal Hamstrings Avulsions |
Actual Study Start Date : | October 24, 2017 |
Actual Primary Completion Date : | September 30, 2022 |
Estimated Study Completion Date : | November 15, 2022 |
Arm | Intervention/treatment |
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No Intervention: Non-operative treatment
Active rehabilitation program
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Active Comparator: Operative treatment
Surgical reattachment of hamstring tendons using suture anchors followed by active rehabilitation program
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Procedure: Surgical reattachment of hamstring tendons
operatively reattachment of the tendons using suture anchor |
- Perth Hamstrings Assessment Tool (PHAT) [ Time Frame: 24 months post surgery ]The PHAT is a 8-item instrument that measures pain, function and discomfort of the hamstrings. Primary endpoint at 24 months (measured at 3, 6, 12, and 24 months). The maximum score is 100 indicating no symptoms and high function.
- Lower extremity functional scale (LEFS) [ Time Frame: 24 months post surgery ]LEFS is a 30-item instrument that measure patient perceived function of the lower extremities. Primary endpoint at 24 months (measured at 3, 6, 12, and 24 months). The maximum possible score is 80 points, indicating very high function.
- Maximal isokinetic strength of hamstrings [ Time Frame: 24 months post surgery ]The difference between the two treatment groups in the mean ratio between the injured and uninjured side of the maximum isokinetic force during knee flexion and hip extension measured by a dynamometer. Primary endpoint at 24 months (measured at 3, 6, 12, and 24 months).
- Timed step test [ Time Frame: 24 months post surgery ]The difference between the two treatment groups in the mean ratio between the injured and uninjured side of the functional timed step test. Primary endpoint at 24 months (measured at 3, 6, 12, and 24 months).
- Single hop test [ Time Frame: 24 months post surgery ]The difference between the two treatment groups in the mean ratio between the injured and uninjured side of the single leg hop test. Primary endpoint at 24 months (measured at 3, 6, 12, and 24 months).
- Hamstrings muscle volume and density [ Time Frame: 24 months post surgery ]Volume and density measured by computerized tomography at 24 months
- Adverse events [ Time Frame: up until last follow-up at 24 months ]Peripheral neurological injury and symptoms, infection, wound complications, thromboembolic disease and any serious adverse events

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 30 Years to 70 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion criteria
- age of the patient at injury between 30 and 70
- MRI shows a complete avulsion of at least two of three tendons from the insertion at the ischial tubercule
- physical examination supports the diagnosis; e.g. a positive hip extension test, palpable defect and/or local tenderness and hematoma
- patient has a moderate to high activity level
- patient has linguistic and mental ability to understands study program explained in Swedish, Finnish, Norwegian or English
- time from injury to inclusion in study is less than 4 weeks
A patient with moderate to high activity level is defined as any patient that is ambulatory in the community and participates in some type of strenuous activity at work or in spare time on a regular basis. Any patient that skis, goes for an occasional run, takes long walks in the woods, climbs ladders or physically manages a large garden have an activity level that is at least moderate.
Exclusion criteria
- diabetes with secondary complications
- previous major lower extremity injury or disease with sequelae
- moderate or severe liver, pulmonary, kidney, psychiatric or heart disease that significantly increases the risk for complications after operative treatment
- severe obesity (BMI>35)
- alcohol or drug abuse
- high energy injury or combinations of injuries affecting the lower extremity

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03311997
Finland | |
Tampere University Hospital | |
Tampere, Finland | |
Norway | |
Bergen University Hospital | |
Bergen, Norway | |
Oslo University Hospital | |
Oslo, Norway | |
Sweden | |
Linköping University Hospital | |
Linköping, Sweden, 581 85 | |
Malmö University Hospital | |
Malmö, Sweden | |
Södersjukhuset | |
Stockholm, Sweden, 118 83 | |
Danderyd hospital | |
Stockholm, Sweden, 182 88 | |
Norrlands University Hospital | |
Umeå, Sweden, 581 85 | |
Uppsala University Hospital | |
Uppsala, Sweden, 75185 | |
Örebro University Hospital | |
Örebro, Sweden, 701 85 | |
Östersund Hospital | |
Östersund, Sweden, 831 83 |
Principal Investigator: | Kenneth Jonsson, MD.Ph.D | Uppsala University |
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Uppsala University |
ClinicalTrials.gov Identifier: | NCT03311997 |
Other Study ID Numbers: |
UU2017/170 |
First Posted: | October 17, 2017 Key Record Dates |
Last Update Posted: | November 3, 2022 |
Last Verified: | November 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | De-identified individual participant data for all primary and secondary outcome measures will be made available |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) Informed Consent Form (ICF) |
Time Frame: | Within 6 months of study completion |
Access Criteria: | Data access request will be reviewed by independent University leaders. Requestors will be required to sign DAA |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
RCT Hamstring Suture |
Tendon Injuries Wounds and Injuries |