The BFF Study- The Better to Fix or Fuse Study

The Foot and Ankle Outcome Score (FAOS) is a 42-item questionnaire of patient-relevant outcomes in five, questionnaire for patients who have musculoskeletal disorders of the upper and lower extremities, for the ankle- hindfoot, midfoot, hallux, and lesser toes.

It incorporates both subjective and objective information. Patients report their pain, and physicians assess alignment. The patient and physician work together to complete the functional portion. Scores range from 0 to 100, with a healthy midfoot receiving 100 points.

The Foot and Ankle Disability Index is a 34-item questionnaire divided into two subscales: the Foot and Ankle Disability Index and the Foot and Ankle Disability Index Sport. The FADI has 26 items, and the FADI Sport has 8. The FADI contains 4 pain related items and 22 activity related items. The FADI Sport contains 8 activity related items. It assesses more difficult tasks that are essential to sport.

Each of the 34 items is scored on a 5-point Likert scale from 0 (unable to do) to 4 (no difficulty at all). The 4 pain items of the FADI are scored 0 (none) to 4 (unbearable). The FADI has a total point value of 104 points, whereas the FADI Sport has a total point value of 32 points. The FADI and FADI Sport are scored separately as percentages, with 100% representing no dysfunction.

Radiographs will be interpreted as follow: Instability, e.g. displacement or malalignment will be described as:

• AP view Lateral displacement of 2nd metatarsal on intermediate cuneiform, medial margin of the second metatarsal and the middle cuneiform not aligned; TMT 1 disruption, lateral margin of the first metatarsal not aligned with the lateral margin of the medial cuneiform; Gap between 1st and 2nd metatarsal and/or ceuneiforme medialis and intermedius (>2mm);
• 30 degree oblique view Lateral displacement of 3rd metatarsal on lateral cuneiform, lateral margin of the third metatarsal and the lateral cuneiform not aligned; Medial margin of the fourth metatarsal and cuboid not aligned;
• lateral view Dorsal displacement of the metatarsal bases above the level of the cuneiforms.
• any view Bony avulsion fractures between base 2nd metatarsal and cuneiforme medialis (fleck sign), and/or between cuneiforme medialis and intermedius.

Medical consumption is measured on the basis of 29 questions.The scoring for items starting with "How many appointments did you have ..." is as follows. The number of agreements that the respondent mentions will be adopted. When the respondent has ticked "No appointment at all" a 0 is entered. When the respondent has nothing checked, this should be considered as missing information. Data regarding care items in which a distinction is made between different types of care collected based on multiple questions. The first question about the item in question is always oneselection question. Respondents ticking "No" can skip the following questions and are referred to the next care item via the routing. The answer "No" is scoredwith a 2. The missing values for questions that can be skipped arecoded as a valid missing. Respondents who answer "Yes" are asked further to proceed with the following questions. This asks for a specification of the care item and the number of care received.

most important being post-traumatic arthritis, infection, non-union

The SF-12 measures eight health aspects, namely physical functioning, role limitations due to physical health problems, bodily pain, general health, vitality (energy/fatigue), social functioning, role limitations due to emotional problems, and mental health (psychological distress and psychological well-being). Two summary scores are reported from the SF-12 - a mental component score (MCS-12) and a physical component score (PCS-12). The scores may be reported as Z-scores (difference compared to the population average, measured in standard deviations). The United States population average PCS-12 and MCS-12 are both 50 points. The United States population standard deviation is 10 points. So each 10 increment of 10 points above or below 50, corresponds to one standard deviation away from the average.

Questions 1 to 3 provide information about the amount of paid work (in hours) and the number of days per week on which the person works. The latter provides insight into the average number of hours of work per working day of the respondent. This information is needed to calculate productivity loss costs.

The questions about productivity losses form the following modules: - Absenteeism: absenteeism from paid work (questions 4 to 6) - 'Presenteeism': productivity losses during days worked (questions 7 to 9) - Productivity loss from unpaid work (questions 10 to 12).

Absenteeism:

The total amount of absenteeism is then calculated by multiplying the number of days absent and the number of hours per working day of the respondent.

To calculate the costs of productivity losses, volumes are multiplied by unit cost prices.