|Inclusion Criteria Both Groups|
|(i) aged ≥40 years;|
|Exclusion Criteria Both Groups|
(i) current or previous pain in the knee, hip, lumbar spine or foot that had lasted longer than 3 months and/or required intervention;|
(ii) foot orthoses use in the last 12 months.
(iii) a history of hip, knee or foot surgery;
(iv) neurological or systemic arthritis conditions;
(v) planned lower limb surgery in the following 2 months;
(vi) physical inability to undertake testing procedures;
(vii) an inability to understand written and spoken English.
|Specific Inclusion Criteria PF OA|
(i) anterior knee pain aggravated by at least two activities that load the PF joint (e.g. squatting, stair ambulation);|
(ii) pain during these activities present on most days in the past month;
(iii) pain severity ≥30 mm on a 100 mm visual analogue scale during aggravating activities;
(iv) radiographic evidence of PF OA (Kellgren and Lawrence ≥ grade 1 ).
|Specific Exclusion Criteria PF OA|
(i) concomitant pain from other knee structures (including the TF joint), hip or lumbar spine;|
(ii) recent treatment for PF pain (knee injections within the previous 3 months;
(iii) foot orthoses or physiotherapy within the previous 12 months)
(iv) moderate to severe concomitant TF OA (Kellgren and Lawrence grade ≥ 3 on radiograph);
(v) contraindications to x-ray.