Photo courtesy Dr. Jennifer Fletcher Eckenrode Effectively managing osteoarthritis (OA) pain is usually top of mind during Pain Management Month. This disease is one of the most common conditions seen in veterinary medicine today, and a major contributor to chronic pain and mobility loss. Published research points to the need for joint-directed interventions that help to alleviate pain and preserve function.1 A newer approach showing promise is radiosynoviorthesis (RSO). A novel radioisotope, tin-117m (Sn-117m), is injected directly into the joint. Following this targeted injection, tin-117m is phagocytosed by synovial macrophages, inducing apoptosis and attenuating the inflammatory cascade without chondrotoxicity or major systemic adverse effects. Research has confirmed significant mobility improvements are sustained up to 12 months with no systemic side effects following a single injection of tin-117m.1-5 A 2026 peer-reviewed article published in the Journal of the American Veterinary Medical Association (JAVMA) reported a strong safety profile for the treatment, with minimal radiation exposure for veterinarians or caregivers. Monte Carlo modeling confirmed that, even under prolonged, close-contact behaviors, cumulative exposures remain below regulatory thresholds, allowing outpatient use without isolation.3 Another recent peer-reviewed article in JAVMA evaluated the experiences of owners who reported their dogs had significant reduction in pain and improvement in daily activities following tin-117m injection. The study involved an anonymous multicenter online survey asking owners to rate changes in pain and mobility, as well as cost, clinical outcome, and sedation/anesthesia. Quantitative analyses showed tin-117m treatment is strongly associated with a high level of overall owner satisfaction.4 These results are being replicated in real-world veterinary practice and are highlighted in the following case studies by veterinary specialists who use the same approach in their practices and with their own pets. Case study #1: Verde the therapy dog As reported by Erin Troy, DVM, CCRP, CVPP, CBW Subject: Verde, a female yellow Labrador retriever and therapy dog History: At 19 months old, Verde awoke one morning unable to bear weight on her right front leg. Dr. Troy immediately performed a workup to determine the cause of the sudden lameness. “I’d had her for just three months and was very concerned about the cause of this in such a young dog,” Troy says. Diagnosis: Radiographic imaging revealed OA in both elbows (Figures 1A and 1B). Radiographic findings of elbow dysplasia with secondary osteoarthritis show joint incongruity and characteristic bony changes: osteophyte proliferation on the anconeal process and joint margins, subtrochlear sclerosis, and possible coronoid fragments. Photos courtesy Dr. Erin Troy. Treatment: Verde’s initial treatment involved platelet-rich plasma (PRP) and hyaluronic acid (HA), with three weekly injections every four months. However, after the fourth round of treatments, the dog was no longer responding. During this time, Troy had become certified to offer RSO with tin-117m. After seeing her dog’s continued decline, she decided Verde would be the first patient she treated with the tin-117m intra-articular injection. Outcome: Verde experienced initial localized soreness at the injection site in each elbow, but shortly thereafter exhibited increasing mobility. “At about five weeks, Verde came bounding through the house one morning, and I knew this had been the right decision for her,” Troy reports. Retreatment: The first tin-117m injection lasted two years before Verde needed a second. “Interestingly, subsequent radiographs have shown an ongoing positive treatment response to tin-117m,” Troy reports. Discussion: Troy now reviews Verde’s case with her clients, emphasizing the importance of early intervention. She says discussing Verde’s response has helped her clients feel more comfortable treating sooner, when, as she says, there’s the best chance of success. Case study #2: Murray the “cuddly giant” As reported by Jennifer Fletcher Eckenrode, DVM, CCRT Subject: Murray, a male Great Pyrenees/Anatolian shepherd mix History: Murray began struggling to get up from a recumbent position and exhibited unusual personality changes at six years old. “He had become despondent and less willing to engage with the family and other pets,” Dr. Fletcher Eckenrode says. Diagnosis: Radiographic imaging revealed arthritis in both hips (Figure 2). Because Fletcher Eckenrode’s practice is almost exclusively rehabilitation and pain management, she knows the toll OA can take on quality of life. “I saw those images, and I just cried because at age six, Murray was still a relatively young dog.” Figure 2. Severe bilateral hip dysplasia with marked coxofemoral subluxation. Subchondral sclerosis is present within the acetabula and femoral heads. The joint spaces are irregular and poorly defined due to advanced degenerative remodeling affecting both hips. Photo courtesy Dr. Jennifer Fletcher Eckenrode. Treatment: Murray was initially treated with NSAIDs for 30 days, but Fletcher Eckenrode did not want to keep the patient on oral medication long-term. She decided to try tin-117m to treat the dog’s OA at the joint level. At that time, her experience with the treatment was exclusively in the elbow but based on the success she had seen in those cases, Fletcher Eckenrode decided to evaluate Murray’s response to treatment of his hips. “I see so many dogs struggling with hip OA, and I thought Murray’s was a good case to determine if tin-117m could be a valid option for other dogs as well,” she says. Response: Four weeks following the injection, Murray was reportedly active and mobile. Fletcher Eckenrode reports the dog “had a great response. He was charging around the backyard and popping up from his bed to greet us. He was more in tune with the family again.” Retreatment: Murray’s hips have now been treated twice with tin-117m. The first injection reportedly lasted about 20 months before Fletcher Eckenrode treated him again. Discussion: Fletcher Eckenrode often discusses Murray’s case with her clients, telling them about the impact of directly addressing the cause of OA and not just the symptoms. Case study #3: Kiba the “street dog” As reported by Eileen Savier, DVM, CVA, CVCH Subject: Kiba, a female mixed-breed former street dog History: At age 11, Kiba began exhibiting worrisome behavioral symptoms. Dr. Savier recalls the dog was “just slower and seemed dimmer and despondent.” Diagnosis: Radiographic imaging revealed mild OA in both elbows (Figure 3). However, this imaging did not add up to the symptoms Savier was seeing in her dog. Figure 3. Elbow dysplasia with secondary degenerative changes. Subchondral sclerosis is present in the region of the trochlear notch. Osteophyte production in the region of the anconeal process and joint margins is evident. Dr. Eileen Savier Treatment: Kiba was initially treated conservatively with a joint supplement but had no improvement. Savier explored treating with tin-117m. Response: Following the tin-117m injection, Kiba experienced soreness in her elbows for the first three days, but by day five, she was showing noticeable improvement. Savier recalls Kiba was up, wagging her tail, and trotting normally around the house, and by day 10, the dog was running around the yard again. Retreatment: Kiba was treated twice with tin-117m. The initial injection lasted about 18 months before she needed a second. “Although Kiba is gone now, she lived a long and happy 16 years. Thanks to tin-117m, those last years were active, happy ones,” Dr. Savier says. Discussion: Savier uses Kiba’s case in her discussions with owners who are seeing not just pain but also behavioral changes. “I want them to know if their dog is showing signs of discomfort or becoming lackluster, it’s key to treat early even if the imaging shows milder disease,” she says. Greg Taglialatela is chief commercial officer with Exubrion Therapeutics. With more than a decade of experience in animal health, Taglialatela is focused on helping practices successfully integrate innovative therapies that deliver meaningful outcomes for patients, pet owners, and veterinary teams. References Bendele A, Doerr CA, Gonzales GR, et al. Evidence of osteoarthritis disease modification with a Sn-117m microparticle device: a review and validation in mammalian models. Vet. Sci. 2025;12:1-13. doi: 10.3389/fvets.2025.1621296. Aulakh KS, Lopez MJ, Hudson C, et al. Prospective clinical evaluation of intra-articular injection of tin-117m (117mSn) radiosynoviorthesis agent for management of naturally occurring elbow osteoarthritis in dogs: a pilot study. Vet Med (Auckl). 2021;12:117-128. doi: 10.2147/VMRR.S295309. PMID: 34113552; PMCID: PMC8187093. Arno MG, Barnhard JA, Webb KR, et al. Tin-117m radiosynoviorthesis safely and effectively manages canine osteoarthritis with minimal radiation exposure: a narrative review. J Am Vet Med Assoc. 2026:1-6. doi: https://doi.org/10.2460/javma.26.01.0041. 2025;264(5):1-5. doi: https://doi.org/10.2460/javma.25.08.0564. Vézina-Audette R, Barnhaard, JA, Brunke MW, et al. Owners report satisfaction and perceived improvement following Sn-117m radiosynoviorthesis in dogs with osteoarthritis. J Am Vet Med Assoc. 2026:1-6. doi: https://doi.org/10.2460/javma.26.01.0041. Lattimer JC, Selting KA, Lunceford JM, et al. Intraarticular injection of a tin-117m radiosynoviorthesis agent in normal canine elbows causes no adverse effects. Vet Radiol Ultrasound. 2019;60(5):567-574. doi: 10.1111/vru.12757. Epub 2019 Jun 2. PMID: 31155782.
