Changes in Postural Stability Following THA for OA

The BESTest is a comprehensive performance-based postural stability assessment tool. The BESTest consists of 36 items that assess each underlying component of the balance systems framework (i.e., static stability, motor systems, functional stability limits, verticality, reactive postural control, anticipatory postural control, dynamic stability, sensory integration, and cognitive influences). Each item is scored from 0 (severe balance impairment) to 3 (no balance impairment). The maximum total score is 108 points with higher scores representing better postural stability.

The 16-item ABC scale assesses the level of confidence a person has in performing a set of daily activities without losing their balance or feeling unsteady. The ABC scale evaluates balance confidence. Each item is rated on scale of 0% (no confidence) to 100% (complete confidence). The final score is the average of all 16-items. ABC scores can be categorized as follows: less than 50 is a low balance confidence, between 50 and 80 is a moderate balance confidence, and over 80 is a high balance confidence.

The UCLA activity scale measures physical activity on a scale from 1 ("no physical activity, dependent on others") to 10 ("regular participation in impact sports"). It has been identified as the most suitable scale for assessing physical activity levels in people undergoing total joint arthroplasty.

The EQ-5D-5L is a generic preference-based measure that evaluates five dimensions of health-related quality of life: mobility, self-care, usual activities, pain/discomfort (PD), and anxiety/depression (AD). Each dimension has five response levels representing no, slight, moderate, severe, and extreme problems. In addition to the five dimensions, the EQ-5D-5L includes the EuroQol-visual analogue scales (EQ VAS), which allow individuals to rate their health status on a scale ranging from 0 (worst imaginable health) to 100 (best imaginable health). By using the Canadian EQ-5D-5L value set, health state utility values can be assigned to an EQ-described health state, ranging from -0.148 (representing 55,555) to 0.949 (representing 11,111). This is referred to as EQ-5D-5L utility.

The Harris Hip Score is an outcome measure completed by the surgeon and evaluates four domains related to the operated limb: pain, function, range of motion and absence of deformity. The score ranges from 0 (lowest outcome) to 100 (best outcome). Scoring can be interpreted as poor (<70), fair (70-79), good (80-89) or excellent (90-100).

The WOMAC is a patient self-administered 24-item questionnaire divided into 3 subscales that assess pain, stiffness and joint function. For this study, a weighted and inverted conversion will be used for each domain with a maximum score of 100, where a higher score will indicate better overall health status.

A history of fall questionnaire will be provided to participants to ascertain any falls that occurred in the previous 12 months before the THA surgery, circumstances of falls, and if any injuries occurred.

A fall will be defined as an "unintentional coming to rest on the ground, floor or other lower level". Injuries will be categorized as major or minor. A major injury is defined as any fall that necessitates medical attention for the treatment of a fracture, while a minor injury is a bruise or laceration, where medical attention may or may not have been necessary.

Participants will be provided with a journal to record any falls (daily), circumstances of falls and information on any injuries. A face-to-face meeting will be conducted during their postoperative appointments to rectify any missing information. A fall will be defined as an "unintentional coming to rest on the ground, floor or other lower level". Injuries will be categorized as major or minor. A major injury is defined as any fall that necessitates medical attention for the treatment of a fracture, while a minor injury is a bruise or laceration, where medical attention may or may not have been necessary.