Clinical Trial 30876


Broomfield, CO 80021

Study Summary:

There are an estimated 80,000 to 100,000 anterior cruciate ligament (ACL) repairs in the United States each year. Most ACL tears occur from noncontact injuries. The knee ACL provides stability to the knee joint and can be torn by trauma or can tear through age related degeneration. Surgical replacement with either an allograft (donor tissue) or autograft (your own tissue) is often used for these tears. However, recent research has suggested that no high level evidence exists that surgery is superior to conservative (non-surgical) care. The ACL contains fibrocytes (cells found in tissue such as tendons and ligaments) and adult stem cells (cells that can become different cell types to aid in healing). These cells have been characterized as similar to the mesenchymal stem cells found in bone marrow. However, the stem cells found in ACL ligaments aren’t as biologically robust as those found elsewhere in the knee, perhaps explaining why knee ACLs heal much more slowly. As a result, some doctors have begun to wonder if injecting the ACL with biologics may aid healing as an alternative to surgery. Regenexx™ SD for ACL repair is a procedure in which components of bone marrow from the back of your hip and blood drawn from your arm are concentrated and re-injected into the damaged ACL.

Some doctors recommend a period of physical therapy (Exercise Therapy) for certain ACL injuries first to see if the ACL heals on its own. By protecting the knee for a period of time, performing exercises to restore knee motion and strengthening the surrounding muscles, some studies have shown improvement in knee function for certain ACL injuries.

The primary purpose of this study is to compare the improvement in certain ACL tears treated with either Regenexx™ SD or Exercise Therapy alone. Fifty (50) patients will be enrolled in the study, 25 in the Regenexx SD group and 25 in the Exercise Therapy group.

Before you are entered into the study, the following procedures will be done to evaluate your eligibility:

  • a Knee examination
  • documentation of medical and knee history and medication use
  • collection of any recent imaging such as an MRI.
If you qualify for the study you will then be asked to complete a set of brief surveys about your knee condition.

You will then be randomized (chosen by chance) into one of two treatment groups:
  • Regenexx SD injection
  • Exercise Therapy
Treatment groups will be randomized in a 1:1 ratio, meaning that you have an equal chance of being assigned to each group.

If you are randomized to the Exercise Therapy group you will have the opportunity to cross-over to the Regenexx-SD treatment group after the 3 month follow-up visit if you do not show improvement in your knee condition. This can occur at any time after the 3 month visit per your doctor’s assessment and discussions about your treatment options with you as the patient. If you qualify to cross-over to the Regenexx SD treatment group, the Regenexx SD procedure will be provided to you at no cost. You will then be requested to continue follow-up for 2 years following the injection date. Follow-ups will include clinic visits and completion of a set of brief surveys about your knee condition.

Candidates must meet ALL of the following:
  • Voluntary signature of the IRB approved Informed Consent
  • Skeletally mature Male or Female
  • ages 18 to 65
  • Pain, swelling, or functional disability in the affected knee with activity, having failed conservative treatment (e.g. NSAIDs, physician initiated physical therapy) for at least 3 months or unable to return to normal day to day activities by 6 weeks
  • Physical examination consistent with a lax ACL ligament (Anterior Drawer Test)
  • Abnormal Telos Arthrometer measurement
  • Positive diagnostic MR imaging of the affected knee with at least 1/3 of the ACL ligament at any area along its length having high signal on MRI PDFS/Fat Sat images
  • Full range of motion of the affected knee (other than restriction clearly due to effusion)
  • Normal range of motion of the non-treated knee
  • Is independent, ambulatory, and can comply with all post-operative evaluations and visits
Candidates will be excluded if they meet ANY of the following:
  • A massive ACL tear or one that includes more than 2/3’rds of the ligament that’s retracted
  • Previous surgery to the affected ACL (i.e. previous ACL replacement with an autograft or allograft)
  • Prior ACL prolotherapy, PRP, corticosteroid injection or other injection therapy within the past three months
  • Concomitant meniscus tear or cartilage injury that occurred at the same time as the as the ACL tear and which is considered a pain generator by the treating physician at the time intake into the study (i.e. a meniscus tear or cartilage lesion associated with an active BML [Bone Marrow Lesion])
  • Concomitant PCL, MCL, or LCL tears
  • Inflammatory or auto-immune based joint diseases or other lower extremity pathology (e.g., rheumatoid arthritis, systemic lupus erythematosus, psoriatic arthritis, polymyalgia, polymyositis, gout pseudogout)
  • Quinolone or Statin induced myopathy/ tendinopathy
  • Kellgren-Lawrence grade 2 or greater knee osteoarthritis
  • Significant knee extension lag compared to the opposite knee
  • Symptomatic lumbar spine pathology (e.g. radicular pain)
  • Severe neurogenic inflammation of the cutaneous nerves about the knee or thigh
  • Contraindications for MRI
  • Tested positive or has been treated for a malignancy in the past or is suspected of having a malignancy or is currently undergoing radiation or chemotherapy treatment for a malignancy anywhere in the body, whether adjacent to or distant from the proposed injection site
  • Condition represents a worker's compensation case
  • Currently involved in a health-related litigation procedure
  • Is pregnant
  • Bleeding disorders
  • Currently taking anticoagulant or immunosuppressive medication
  • Allergy or intolerance to study medication
  • Use of chronic opioid
  • Documented history of drug abuse within six months of treatment
  • Any other condition, that in the opinion of the investigator, that would preclude the patient from enrollment.

Qualified Participants May Receive:

Treatment provided at no cost.

Study is Available At:

Centeno-Schultz Clinic
403 Summit Blvd.
Suite 201
Broomfield, CO 80021
View Clinic Location


If you or someone you care for is interested in participating in this clinical trial and lives within 100 miles of the clinic, please complete the form below and click 'I Am Interested In This Study'

Clinical trials are medical research studies designed to test the safety and/or effectiveness of new investigational drugs, devices, or treatments in humans. These studies are conducted worldwide for a range of conditions and illnesses. Learn more about clinical research and participating in a study at About Clinical Trials.