CT-VERIFIED UNION RATE FOLLOWING ARTHRODESIS OF ANKLE, HINDFOOT, OR MIDFOOT: A SYSTEMATIC REVIEW AND META-ANALYSIS

Ankle, hindfoot, and midfoot arthrodesis surgeries are standard procedures performed in orthopaedics to treat pain and functional disabilities caused by various pathologies. While fusions can effectively improve pain and quality of life, non-unions remain a significant concern for surgeons. Traditionally, clinical scales and plain radiographic films determined the success of the fusion. With the increased availability of computed tomography (CT), more surgeons rely on this modality for increased accuracy in determining whether a fusion was successful. Limited studies are available investigating the CT-verified fusion rates of ankle, hindfoot, and midfoot fusions; this study aims to elucidate the overall fusion rate from the current literature. A systematic review and meta-analysis was performed following PRISMA guidelines using EMBASE and Medline databases from January 2000 to March 2020. Randomized controlled trials, observational cohort studies, case-control studies, and case series were selected for review if they included more than ten patients whose age was 18 or older and had ankle, hindfoot, or midfoot fusions with 75% of the cohort receiving CT scans postoperatively to evaluate union. The primary outcome was to determine the current fusion rates of ankle, hindfoot, and midfoot arthrodesis surgeries as confirmed by CT. In total, 4,601 citations were screened, resulting in 24 articles being included in the systematic review. A total of 1015 patients were included in the study. The mean age of patients included in the analysis was 55.9 years old, with a mean follow-up of 48 months. The average time from arthrodesis to CT scan was 21.9 weeks. The overall fusion rate for all patients included in the study was 78.7%. Talonavicular joint (TNJ) fusions had the highest rate of CT verified union at 90%, while the fusion rate for hindfoot procedures was 78%. In subgroup analysis, we found that the fusion rate was statistically significantly worse in male patients and those who smoked with odd ratios of 1.53 (p = 0.04) and 1.94 (p = 0.04), respectively. Diabetes did not show a statistically significant effect on union rates. Arthrodesis is often used to treat symptomatic arthritis of the ankle, hindfoot, and midfoot. This review examines the CT-verified fusion rates for these procedures and compares them to plain film radiograph-confirmed fusion rates. As confirmed by CT, the total rate of non-union of all patients undergoing ankle, hindfoot, or midfoot fusions was 21.3%. This should give patients and surgeons pause when discussing the risks of arthrodesis surgery and offers a more accurate value for informed consent. It is not clear, based on the results of this study, if a routine assessment of union based on CT would improve patient outcomes, however, the results may encourage practitioners to obtain a CT scan in the setting of ongoing pain after fusion surgery despite the radiographic appearance of union.