Mid-Term Results after Lateral Transfibular Approach Total Ankle Arthroplasty

Abstract

Category: Ankle Arthritis; Ankle Introduction/Purpose: Continued improvements in total ankle arthroplasty (TAA) implant design have led to promising clinical outcomes. The lateral transfibular approach TAA allows for excellent visualization of the center of rotation of the ankle and allows for correction of rotational and sagittal deformity by shortening or lengthening of the fibula. Furthermore, the curved implant design allows for minimal bony resection. The purpose of this study is to report the medium-term clinical and radiographic results for consecutive patients who underwent the lateral approach TAA. Methods: IRB approval was obtained for this study. Consecutive patients who underwent lateral approach TAA for tibiotalar arthritis by a single surgeon were enrolled on a prospective basis from January 2013 to June 2015. This time period represented the initial case series of TAA performed by the surgeon. Patient reported outcomes (PROs) were collected including the Ankle Osteoarthritis Scale (AOS), 12-item short-form survey (SF-12), and Visual Analogue Pain Scale (VAS). The need for subsequent procedures was recorded. Radiographs were evaluated for preoperative and postoperative alignment using the lateral distal tibial angle (LDTA), tibiotalar surface angle (TTS), anterior distal tibia angle (ADTA), and the lateral talar station (LTS). Radiographs were also evaluated for the development of peri-implant lucency and subsidence. Data was tested for normality. T-tests were used to determine differences between preoperative data and postoperative data. A p<0.05 was considered significant. Results: 53 patients who underwent 59 TAA procedures were included. Average follow-up was 5.7 +/- 0.9 years. Average age was 53 +/- 7.0. Comorbidities included smoking (11/53), diabetes (6/53), and prior procedures (33/53). Sixteen ankles (27%) underwent one or more subsequent procedures including gutter debridement (7/59), debridement for periprosthetic infection (3/59), and removal of hardware (7/59). All fibular osteotomies healed. Four ankles had asymptomatic peri-implant lucency or cysts (4/59). No patients had subsidence or required revision of the tibial or talar components. Coronal and sagittal alignment were significantly improved for all measures (p<0.05). VAS scores improved from a mean of 7.5 preoperatively to 1 at final follow- up (p<0.0001). SF-12 physical component scores improved from 34 to 41.5 (p=0.0227). AOS scores improved from 54.8 to 19.1 (p<0.0001). Conclusion: At medium term follow-up, patient reported outcomes remain significantly improved in patients after lateral approach TAA. There were very few radiographic findings of lucency and cyst formation, and all of these were asymptomatic. No revision of metal implants was required. Excellent deformity correction was achieved. The rate of subsequent procedures was high, although the rate of actual component revision was 0%. Lateral approach TAA appears to have overall good outcomes at medium term follow-up.