Abstract
BACKGROUND: The rate of total ankle arthroplasty (TAA) is projected to continue increasing. Implant malalignment is a significant predictor of complications; however intraoperative evaluation of alignment can be challenging. Patient-specific instrumentation (PSI) was designed to improve implant positioning in TAA. This study compares radiographic alignment and postoperative function in patients who underwent TAA with PSI with an Infinity implant vs standard instrumentation (SI) with a Salto Talaris implant. METHODS: We retrospectively reviewed 114 TAA cases using PSI compared with 80 TAA surgeries using SI. Demographics, radiographic alignment, range of motion (ROM), complications, and postoperative American Orthopaedic Foot & Ankle Society (AOFAS) pain, function, and alignment scores were compared at a minimum 1-year follow-up. RESULTS: The PSI cohort demonstrated significantly better radiographic alignment, particularly in tibial component positioning, and reduced frequency of lucencies compared with the SI cohort. However, operative time was significantly longer in the PSI group (mean 119.0 ± 34.5 vs 96.3 ± 26.0 minutes; P < .001). For the coronal alignment of the tibial component, PSI alignment was 1.7° (0.0°-10.2°) and 2.5° (0.0°-9.8°) for SI (P = .002). For the sagittal alignment of the tibial component, alignment was observed to be 2.9° (0.0°-9.9°) for PSI and 6.1° (1.0°-13.0°) for SI (P < .001). The PSI cohort had increased AOFAS alignment scores (mean = 9.7 vs 8.9, P = .002), but AOFAS total scores were similar (mean = 77.7 vs 79.2, P = .539) between cohorts. Similar numbers of patients required revision (1.75% for PSI, 1.25% for SI, P = 1.00) or irrigation and debridement (3.51% for PSI, 3.75% for SI, P = 1.00). CONCLUSION: In this study, PSI was associated with modest differences in tibial alignment and early radiographic lucencies compared with SI, without clear significant differences in short-term clinical outcomes. Both cohorts had similar postoperative range of motion and AOFAS scores. Given the retrospective design and short follow-up, further investigation is needed to assess long-term clinical impact and implant survivorship. LEVEL OF EVIDENCE: Level III, retrospective comparative study.