Protect Your Future Knee

Post-Traumatic Osteoarthritis is common after an ACL injury — The BEAR® Implant helps reduce that risk

A smiling parent enjoying quality time with their child in a living room by lifting them up in the air with their hands and feet

What is Post-Traumatic Osteoarthritis?

Post-Traumatic Osteoarthritis, or PTOA, refers to the “wear and tear” on the joint cartilage caused by a traumatic injury.

There is currently no cure for PTOA – available treatments focus on managing symptoms rather than restoring joint health. Once the joint begins to wear down, that damage cannot be reversed. More than half of U.S. adults with symptomatic knee osteoarthritis, including PTOA, will eventually undergo a total knee replacement.1

PTOA is a leading cause of disability among adults in the U.S. and is associated with consequences including:2,3

  • Chronic Pain
  • Reduced mobility
  • Reduced physical activity
  • Reduced work capacity
  • Lower overall quality of life
A close-up computer-generated skeletal image of a knee with damage
A close-up computer-generated skeletal image of a healthy knee

The Hidden Cost of ACL Reconstruction

1 An ACL tear can increase the risk of developing PTOA, regardless of how it is treated – whether with surgery or non-surgical care.

2 ACL reconstruction (ACLR) is the curren standard treatment and is effective at restoring stability to the knee. However, it does not directly address or prevent the biological processes triggered by the injury that can lead to long-term joint damage.

3 During ACLR, the torn ligament is removed and replaced with a tendon graft. While this restores function, it also changes the natural biology and mechanics of the knee joint. This has significant long-term consequences: nearly 50% of patients who undergo ACLR develop PTOA in the future.4,5,6

A person on a pickleball court kneeling down and holding his knee with his hands
A medium headshot photo of Dr. Theodore Shybut
“For many young athletes, the enduring health and function of their knee will ultimately carry far greater significance than a handful of high school sport seasons”

Dr. Theodore Shybut, Orthopedic Surgeon
Southern California Orthopedic Institute

The BEAR® Implant Prevents PTOA after ACL Injury

In clinical studies, patients with ACL tears treated with the BEAR Implant had a 6x lower rate of PTOA compared with people who had ACLR with a hamstring graft. At six years after surgery:

The BEAR Implant achieves this because it does something no other ACL surgery does — it helps restore your own ACL instead of removing it and replacing it with a graft. By preserving your body’s natural ligament and alignment, the biology and mechanics of the knee that protect it from long-term wear and tear are maintained.

A graph indicating that 33% of ACLR patients show signs of osteoarthritis compared to only 5% of BEAR Implant patients

How the BEAR Implant is different:

  • Allows your natural ACL to heal
  • Less invasive procedure
  • No graft or second surgical site needed
  • Promotes long-term knee joint health by reducing the risk of PTOA

The decisions you make now will shape how your knee feels in the future. The BEAR Implant isn’t just about getting back to sport — it’s about staying active for life.

To learn more about how the BEAR Implant promotes knee joint longevity, read our PTOA blog post.

Read Blog Post

Sidelined with Questions?

Post-traumatic osteoarthritis, or PTOA, is a type of joint “wear and tear” that can develop after an injury like an ACL tear. It can lead to knee pain, stiffness, swelling, reduced activity, and long-term changes in how your knee feels and functions.

There is currently no cure for PTOA, other than total knee replacement, and available treatments focus on managing symptoms rather than restoring joint health.

The risk of osteoarthritis after an ACL tear begins at the moment the injury occurs. When the ligament tears, trauma triggers inflammation inside the knee joint. Over time, this inflammatory response can damage cartilage and other structures that help the joint move smoothly. These combined effects may contribute to the gradual wear and tear on the knee joint known as post-traumatic osteoarthritis. Many orthopedic specialists now discuss ACL treatment through a joint preservation lens, considering how treatment choices may affect the knee years or even decades later.

While ACL reconstruction is effective at restoring stability to the knee, it does not directly address the biological and mechanical changes that can happen after an ACL tear. In fact, studies have shown that up to 50% of patients who undergo ACL reconstruction develop signs of PTOA within 10 years after surgery. This is of particular concern for younger athletes, because someone who tears their ACL in high school could begin experiencing arthritis symptoms while still in their twenties

Traditional ACL surgery replaces your torn ligament with a graft—usually taken from your own leg or a donor. That means removing the damaged ACL entirely. The BEAR Implant helps your own ACL heal naturally by reconnecting the torn ends using a special implant and a small amount of your own blood. There's no graft, no need to borrow tissue, and your knee’s natural structure stays intact. It’s a fresh way to recover that keeps more of you in your knee.

How is the BEAR Implant Different from Reconstruction?

Yes. The BEAR Implant is the first sports medicine product to include a label claim related to reduced PTOA risk. In clinical studies, patients treated with the BEAR Implant had a six times lower rate of PTOA at 6 years compared with patients who had ACL reconstruction with a hamstring graft.

  • 5.7% of patients treated with the BEAR Implant showed signs of osteoarthritis
  • 33% of patients treated with ACL reconstruction showed signs of osteoarthritis

Talk to your doctor to understand what this may mean for your long-term knee joint health.

The exact reason the BEAR Implant is associated with a lower risk of PTOA is not completely understood. However, one possible explanation is that the BEAR Implant helps restore your own ACL, rather than removing it and replacing it with a graft. By preserving the natural shape, size, and function of the ACL, the BEAR Implant may help maintain more normal knee joint mechanics over time.

The BEAR Implant is available across the U.S. in every state. Tap the button below to search for trained BEAR surgeons near you.

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Our PT locator map can be used to search for physical therapists in your area who’ve been trained in the BEAR Implant rehabilitation.

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You may be eligible for the BEAR Implant if you have a partial or complete ACL tear as confirmed by MRI.

While patients in our early clinical studies were required to have surgery within 50 days of ACL injury, real world experience has shown ACL tissue quality, not time, determines eligibility for the BEAR Implant.

Children as young as 2 years old may be candidates for the BEAR Implant.

The overall procedure is very similar regardless of patient age. If your child is skeletally immature, their surgeon will use a growth plate sparing technique to avoid disrupting the natural growth process.

Visit our Children & Parents Page
  1. Weinstein AM, Rome BN, Reichmann WM, et al. Estimating the burden of total knee replacement in the United States. J Bone Joint Surg Am. 2013;95(5):385-392. doi:10.2106/JBJS.L.00206
  2. Leifer VP, Katz JN, Losina E. The burden of OA-health services and economics. Osteoarthritis Cartilage. 2022;30(1):10-16. doi:10.1016/j.joca.2021.05.007
  3. Langworthy M, Dasa V, Spitzer AI. Knee osteoarthritis: disease burden, available treatments, and emerging options. Ther Adv Musculoskelet Dis. 2024;16:1759720X241273009. Published 2024 Sep 15. doi:10.1177/1759720X241273009
  4. Struewer J, Ziring E, Frangen TM, et al. Clinical outcome and prevalence of osteoarthritis after isolated anterior cruciate ligament reconstruction using hamstring graft: follow-up after two and ten years. Int Orthop. 2013;37(2):271-277. doi:10.1007/s00264-012-1653-z
  5. Janssen RP, du Mée AW, van Valkenburg J, Sala HA, Tseng CM. Anterior cruciate ligament reconstruction with 4-strand hamstring autograft and accelerated rehabilitation: a 10-year prospective study on clinical results, knee osteoarthritis and its predictors. Knee Surg Sports Traumatol Arthrosc. 2013;21(9):1977-1988. doi:10.1007/s00167-012-2234-9
  6. MOON Group, Everhart JS, Jones MH, et al. The Clinical Radiographic Incidence of Posttraumatic Osteoarthritis 10 Years After Anterior Cruciate Ligament Reconstruction: Data From the MOON Nested Cohort. Am J Sports Med. 2021;49(5):1251-1261. doi:10.1177/0363546521995182
  7. Miach Orthopaedics, Inc. 510(k) Summary: BEAR® (Bridge-Enhanced ACL Restoration) Implant (K251214). January 8, 2026

Be sure to discuss your individual symptoms, diagnosis and treatment with your surgeon. The BEAR Implant has the same potential medical/surgical complications as other orthopedic surgical procedures, including ACL reconstruction. These include the risk of re-tear, infection, knee pain, meniscus injury and limited range of motion.

The BEAR Implant was cleared by the U.S. Food & Drug Administration and is indicated for adults, adolescents and children with a complete or partial rupture of the ACL, as confirmed by MRI. Patients must have an ACL stump attached to the tibia to construct the repair. Children with open physes must have sufficient bone in the femoral and tibial epiphyses on either side of the intended tunnel locations to avoid disruption of the growth plates.

It is important to follow the BEAR Implant rehabilitation program. Your surgeon or physical therapist can explain the program details.