Functional evaluation of the results of the Hyaluronic Acid Injection in the subtalar joint in patients with post-traumatic Osteoarthritis who underwent Osteosynthesis of the calcaneus with a Kirschner wire

Osteoarthritis affects about 250 million people worldwide, constituting one of the main causes of morbidity. In the subtalar joint, it mainly affects young, economically active patients, leading to socioeconomic losses. In this context, its predominant etiology is due to calcaneal fracture, of which approximately 3.5% may progress to subtalar arthrodesis in five years. Due to the lower patient satisfaction rate in cases of subtalar arthrodesis secondary to trauma compared to arthrodesis resulting from a primary cause, it becomes necessary to discuss the use of alternatives within the conservative therapeutic arsenal, including viscosupplementation. There are few clinical studies that analyze the use of viscosupplementation in the subtalar joint and yet, its long-term effect is unknown. In this study, a clinical and radiographic evaluation of 34 participants was performed three years after subtalar intra-articular infiltration with hyaluronic acid (HA, n=11), corticosteroids (C, n=11) or combination of both for the treatment of osteoarthritis (HA+C, n=12) secondary to calcaneal fracture. We evaluated the impact of subtalar viscosupplementation on pain, function and clinical outcome in these patients. The Visual Analog Scale (VAS) and American Orthopedic Foot and Ankle Society (AOFAS) scores were used for clinical evaluation of pain and function, in addition to radiographs for evaluation of the degree of osteoarthritis according to the Kellgren & Lawrence classification. After three years of infiltration, the median value of the VAS score of the HA group was lower than the value before the procedure, while the C and HA+C groups had the same pre- and post-infiltration value (p=0.47). The HA group showed an increase in the median AOFAS score after 3 years, while the C and HA+C groups showed a reduction in the score compared to the value prior to infiltration (p=0.22). The evolution of the osteoarthritis degree was observed in 70% of the participants in the C group compared to 44.4% in the HA group and 33.3% in the HA+C group (p=0.22). In addition, it was verified that some participants underwent arthrodesis surgery, comprising 33% in the C group compared to 15.4% in the HA group and 23.1% in the HA+C group (p=0.57). Although the results do not show statistical difference between the groups, taken together, they may suggest a tendency towards worse clinical and radiographic results in patients submitted to intra-articular infiltration with isolated corticosteroids, as well as a protective profile of viscosupplementation three years after the injections, reinforcing the need for further studies on this topic