Lateral Trans-Fibular Total Ankle Replacement Capability in Correcting Ankle Osteoarthritis Deformities and Improving Clinical Outcomes

Abstract

Category: Ankle; Ankle Arthritis; Hindfoot; Other Introduction/Purpose: Total ankle replacement (TAR) has been shown as a viable surgical option to reduce pain, improve function, and preserve ankle joint range of motion in patients with Ankle osteoarthritis (AO). Standard anterior approach TAR capability in correcting deformities is already established by several studies. However, there is a paucity of literature evaluating patient outcomes as well as the potential to correct alignment using a lateral approach TAR. Therefore, the primary objective of this study was to assess the capability of lateral trans-fibular approach TAR in correcting coronal and sagittal plane deformity and secondarily to report the ability to improve patient-reported outcomes (PROs) following lateral TAR. Methods: This IRB-approved, retrospective comparative study included 14 consecutive patients that underwent lateral trans- fibular approach TAR for end-stage AO. Average age and BMI were 63.9 years (range 43-83) and 32.7 kg/m2 (SD 7.5). All patients had received pre- and post-operative weight-bearing CT imaging on the affected foot and ankle. Foot and Ankle Offset (FAO), Talar Tilt Angle (TTA), Hindfoot Moment Arm (HMA), and Lateral Talar Station (LTS) were performed. PROs were collected pre- and post-operatively at the latest clinical follow-up including: PROMIS Global Physical Health score, the Tampa Scale of Kinesiophobia (TSK), the European Foot and Ankle Society (EFAS) score, the Pain Catastrophizing Scale (PCS) and the Foot and Ankle Ability Measure (FAAM) Daily Living Score. One-way ANOVA and Wilcoxon tests were used for comparison at each interval time period. A multivariate regression analysis was then performed to evaluate the association between change in alignment and improvements of PROs. Results: Three of 14 patients (21.4%) underwent a concomitant osseous re-alignment procedure. At an average of 16.1 months (range 11 to 24), all patients demonstrated a significant deformity correction in measurements performed: FAO (7.73% - 3.63%, p=0.031), HMA (10.93mm - 5.10mm, p=0.037), TTA (7.9o - 1.5o, p=0.003), and LTS (5.25mm - 2.83mm, p=0.018). Four of the PROs demonstrated significant improvement postoperatively: TSK (42.7-34.5, p=0.012), PROMIS Global Physical Health (46.1- 54.5, p=0.011), EFAS (5-10.3, p=0.004), and FAAM (60.5-79.7, p=0.04). PROMIS was associated (p=0.0015) with optimization of FAO (p=0.00065) and LTS (p=0.00436), R2 of 0.98). Improvements in TSK were associated with changes in the HMA (p=0.0074), R2 of 0.66. Improvements in FAAM correlated (p=0.048) with improvements in FAO (p=0.023) and TTA (p=0.029), and an R2 of 0.78. Conclusion: In this retrospective comparative cohort study, the results suggest that the lateral trans-fibular TAR can correct different aspects of AO deformity. Clinical benefit was also demonstrated by the impacted PROs, particularly TSK, PROMIS Global Physical Health, EFAS, and FAAM Daily Living. Direct and strong correlations between deformity correction measurements and the significantly improved PROs were found. The obtained data might help surgeons when planning treatment and may serve as the basis for future comparative prospective studies.