Development of the Performance Of Lower Limb Scale (POLLS) to assess lower limb physical function and performance.

To develop a new PROM that assesses the spectrum of lower limb physical function and performance and test its measurement properties.

First, we conducted a scoping review to identify physical activities commonly assessed in existing functional outcome measures for three knee musculoskeletal conditions (knee osteoarthritis, anterior cruciate ligament injuries, and patellofemoral pain). Second, we selected 40 commonly assessed physical activities and conducted a discrete choice experiment to explore their perceived difficulty and importance. Finally, we selected the most important physical activities across the difficulty spectrum to create a draft instrument. Stakeholders (people with lived experience of osteoarthritis, researchers, and clinicians) collaborated and participated in all decision-making. We are now conducting a prospective observational study to test the measurement properties (validity, reliability and item difficulty) of the preliminary version of the new PBOM using Rasch methodology. 

We selected 24 physical activities (13 unilateral, 11 bilateral) for the draft Performance Of Lower Limb Scale (POLLS). These activities range from ‘extending the leg while sitting’ (hypothesised easiest activity) to ‘hopping up a 60 cm box’ (hypothesised hardest activity). Each activity is scored pass (1) or fail (0). The total score ranges from 0 to 24, with higher scores indicating higher physical function. This preliminary POLLS is being tested in a prospective study that will conclude in February 2025. Rasch analysis will inform final item selection. Full results will be available for presentation at the World Physical Therapy Congress 2025. 

Following a thorough process that involved conducting a scoping review, a discrete choice experiment and interaction with relevant stakeholders, we developed the preliminary version of a new measure of lower limb functional performance that spans the difficulty spectrum. The measurement properties of this preliminary version are currently being assessed. 

The POLLS will enable objective assessment of lower limb physical performance in people with any level of physical ability. This will improve objective outcome measurement in research and improve the strength of evidence generated for rehabilitation interventions. In addition, this scale has the potential to provide useful and objective information related to deficits in functional capacity that may help physiotherapists target specific goals and individualise rehabilitation. Identifying which activities are more challenging may guide physiotherapists to select specific exercises during rehabilitation to improve performance capacity.