Outcomes following Subchondroplasty in the First Metatarsal Head

CATEGORY: Midfoot/Forefoot; Other INTRODUCTION/PURPOSE: Patients with subchondral bone marrow lesions often present with arthritic symptoms causing severe discomfort. Recently, subchondroplasty has been offered to treat such patients who suffer from symptoms of bone marrow edema. Calcium phosphate is percutaneously injected into these edematous regions to stabilize damaged bone and aid in healing. Subchondroplasty has been used successfully in the knee for femoral and tibial plateau injuries. However, its use in foot and ankle orthopaedics is relatively limited. This procedure has shown short-term success in patients with painful edema of the talus, as well as patients with early stage avascular necrosis (AVN) in the second MTP joint and the cuboid. Here, we report outcomes of two patients who developed AVN as a result of subchondroplasty in foot and ankle surgery. METHODS: A retrospective review of patients was performed in those patients who underwent subchondroplasty in their first metatarsal heads between January 2017 and April 2017. Exclusion criteria included patients lost to follow up. Following implementation of inclusion and exclusion criteria, two patient charts were reviewed. Patients were treated by a single surgeon at the same institution. Data collected included patient demographics (age, laterality, BMI, ASA class, comorbidities), preoperative and postoperative VAS scores, FAOS scores, and imaging. Patients were followed up in clinic for two years following the procedure. Data was then analyzed via mean, standard deviation, median, and range for continuous variables and counts with percentages for categorical data. RESULTS: In both patients, VAS scores increased, and physical exam showed greater tenderness over the affected region. The corresponding MRIs showed development of avascular necrosis in the region of the first metatarsal joint where the subchondroplasty had occurred. Both patients consequently had to undergo revascularization procedures and required further operations to correct the condition. CONCLUSION: Ultimately, subchondroplasty over the first metatarsal head failed in our patients. Exposure to calcium phosphate exacerbated their condition, resulting in symptomatic AVN. Although literature for subchondroplasty in foot and ankle orthopaedics is limited, preliminary results are unfavorable for use in the first metatarsal joint. Therefore, more long term data needs to be gathered this area before implementing the procedure more widely in foot and ankle surgeries.