Preventing Injured Knees from osteoArthritis: Severity Outcomes (PIKASO)

Osteoarthritis (OA) is among the most prevalent chronic, disabling conditions, occurring in over 32 million persons in the US. Worldwide, an estimated 240 million persons have symptomatic, activity-limiting OA. OA cases arising from injury are referred to as post-traumatic OA (PTOA). Approximately 12% of cases of lower extremity symptomatic OA are PTOA, often the result of injuries such as anterior cruciate ligament (ACL) rupture or ankle fracture. Four million Americans have PTOA. On average, patients with PTOA develop knee OA 10.4 years earlier than those with primary knee OA. Similarly, individuals with PTOA of the hip and ankle develop OA 9.0 and 14.0 years, respectively, earlier than their primary OA counterparts. Sustaining ACL injury early in adulthood leads to greater lifetime risk as well as earlier onset of knee OA and need for total knee replacement (TKR). The earlier age of onset means that PTOA is often a disorder of working persons, compromising productivity and quality of life. The indirect cost burden of PTOA is estimated to be \~$4.4 billion annually, because individuals are typically affected in their most productive years of employment.

Anterior cruciate ligament (ACL) injury is the most common sports-related knee injury, and many patients who wish to return to sporting activities that involve cutting and pivoting will choose to undergo ACL reconstruction (ACLR). Each year, more than 120,000 ACL reconstructions are performed in the US alone. Even though ACLR can allow people to return to sporting activities with a stable knee, there is still an increased risk of PTOA after the ACL injury and subsequent reconstruction. Studies have demonstrated that around 50% of patients who undergo ACL reconstruction develop OA within 10-15 years. Given the large number of ACL injuries and subsequent reconstructions that occur annually, and the strong association between ACL tear/reconstruction and PTOA, developing treatment strategies to delay or prevent PTOA and promote long-term health after ACLR is critical to maintaining the well-being of young, active populations. This study proposes to address these issues by testing the efficacy of metformin, a commonly used and safe drug with promising pre-clinical and clinical evidence of PTOA prevention, in younger adults undergoing ACL reconstruction.

PIKASO is a multicenter, double-blind (participants, treating clinicians, and assessors), placebo-controlled, randomized study to establish the efficacy of metformin at delaying the onset of post-traumatic osteoarthritis (PTOA) after anterior cruciate ligament reconstruction. Subjects will be randomized in a 1:1 ratio. Each subject will complete standard-of-care postoperative physical therapy in both arms. The two primary outcomes will be KOOS pain (assessed at 12 and 24 months postoperatively and averaged) and modified MRI Osteoarthritis Knee Score (MOAKS) cartilage score at 24 months postoperatively.