Total Ankle Replacement: Clinical and Radiological Outcomes

Changes in American orthopaedic foot and ankle society (AOFAS) ankle-hindfoot score

The American orthopaedic foot and ankle society (AOFAS) ankle-hindfoot score combines subjective scores of pain and function provided by the patient with objective scores based on the surgeon's physical examination of the patient (to assess sagittal motion, hindfoot motion, ankle-hindfoot stability and alignment of the ankle-hindfoot). The scale includes nine items that can be divided into three subscales (pain, function and alignment). Pain consists of one item with a maximal score of 40 points, indicating no pain. Function consists of seven items with a maximal score of 50 points, indicating full function. Alignment consists of one item with a maximal score of 10 points, indicating good alignment. The maximal score is 100 points, indicating no symptoms or impairments.

Changes in Short form 12 (SF 12)

The SF-12 is a multipurpose short form survey with 12 questions, all selected from the SF-36 Health Survey (Ware, Kosinski, and Keller, 1996). The questions were combined, scored, and weighted to create two scales that provide glimpses into mental and physical functioning and overall health-related-quality of life. Physical and Mental Health Composite Scores (PCS \& MCS) are computed using the scores of twelve questions and range from 0 to 100, where a zero score indicates the lowest level of health measured by the scales and 100 indicates the highest level of health.

Anterior distal tibial angle

(ADTA: normal value 83.0 ± 3.6 degrees). The angle is subtended by the anatomic axis of the tibia and the line connecting the distal points on the anterior and posterior tibial articular surface on the anterior side (Figure 1). The tibia axis was defined as the line connecting the centres of two circles designed over the proximal and the distal tibia adjusting their radius to the anterior and posterior tibial cortices.

Changes in beta angle

β-angle (normal value 85.0 ± 2.0 degrees). This angle is subtended anteriorly by the longitudinal axis of the tibia and the articular surface of the tibial component on the lateral view

Changes in visual analogue scale

The visual analogue scale or visual analog scale (VAS) is a psychometric response scale. When responding to a VAS item, respondents specify their level of agreement to a statement by indicating a position along a continuous line between two end-points.