Background: Patellofemoral pain (PFP) is a common cause of knee pain in adolescents, but there are limited evidence-based treatment options for this population. Foot orthoses can improve pain and function in adults with PFP, and may be effective for adolescents. The primary aim of this study is to determine the feasibility of conducting a full-scale randomised controlled trial (RCT) evaluating the effects of contoured foot orthoses on knee pain severity and patient-perceived global change, compared to flat shoe insoles, in adolescents with PFP. The secondary aim is to provide an estimate of treatment effects for foot orthoses, compared to flat insoles, in adolescents with PFP. Methods: This randomised, controlled, participant-and assessor-blinded, feasibility trial has two parallel groups. Forty adolescents (aged 12-18 years) with clinical symptoms of PFP will be recruited from Queensland, Australia. Participants will be randomised to receive either prefabricated contoured foot orthoses or flat shoe insoles. Both interventions will be fit by a physiotherapist, and worn for 3 months. Feasibility will be evaluated through assessing willingness of volunteers to enrol, number of eligible participants, recruitment rate, adherence with the study protocol, adverse effects, success of blinding, and drop-out rate. Secondary outcomes will evaluate knee-related pain, symptoms, function, quality of life, global rating of change, patient acceptable symptom state, and use of cointerventions, at 6 weeks and 3 months. Primary outcomes will be reported descriptively, while estimates of standard deviation and between-group differences (with 95% confidence intervals) will be reported for secondary outcomes.

Background Patellofemoral pain (PFP) affects one-third of adolescents and can persist into adulthood, negatively impacting health and quality of life. Foot orthoses are a recommended treatment for adults with PFP, but have not been evaluated in adolescents. The primary objective was to determine the feasibility of conducting a full-scale randomised controlled trial (RCT) evaluating effects of contoured, prefabricated foot orthoses on knee pain severity and patient-perceived global change, compared to flat insoles. The secondary objective was to describe outcomes on a range of patient-reported outcome measures. Methods We recruited adolescents aged 12–18 years with PFP of ≥2 months duration into a double-blind, randomised, parallel-group feasibility trial. Participants were randomised to receive prefabricated contoured foot orthoses or flat shoe insoles, and followed for 3 months. Participants and outcome assessors were blinded to group allocation. Primary outcomes were feasibility of a full-scale RCT (number of eligible/enrolled volunteers; recruitment rate; adherence with the intervention and logbook completion; adverse effects; success of blinding; drop-out rate), and credibility and expectancy of interventions. Secondary outcomes were patient-reported measures of pain, symptoms, function, quality of life, global rating of change, patient acceptable symptom state, and use of co-interventions. Results 36 out of 279 (12.9%) volunteers (27 female, mean (SD) age 15 (2) years, body mass 60 (13) kg) were eligible and enrolled, at a recruitment rate of 1.2 participants/week. 17 participants were randomised to receive foot orthoses, and 19 to flat insoles. 15 participants returned logbooks; 7/15 (47%) adhered to the intervention. No serious adverse events were reported. 28% (10/36, 4 pandemic-related) of participants dropped out before 3 months. Blinding was successful. Both groups found the inserts to be credible. Conclusions Based on a priori criteria for feasibility, findings suggest that a full-scale RCT comparing contoured foot orthoses to flat insoles in adolescents with PFP would not be feasible using the current protocol. Prior to conducting a full-scale RCT, feasibility issues should be addressed, with protocol modifications to facilitate participant retention, logbook completion and shoe insert wear. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12619000957190. Date registered: 8/07/2019.

Background Patellofemoral pain (PFP) affects one-quarter of adolescents, yet there are few evidence-informed recommendations to treat PFP in this population. HAPPi Kneecaps! is a randomised, controlled, participant- and assessor-blind, parallel-group feasibility trial of shoe inserts for adolescents with PFP. The aim of this qualitative study was to explore adolescents’ perspectives of participating in HAPPi Kneecaps!. Methods All 36 adolescents with PFP from the HAPPi Kneecaps! study were invited to participate in semi-structured interviews. We used a descriptive qualitative methodology underpinned by a relativist framework to investigate adolescents’ perspectives on participating in the trial. Inductive thematic analysis was used to examine patterns regarding how each adolescent experienced the HAPPi Kneecaps! study within their social, cultural, and historical contexts. Results 14 out of 36 HAPPi Kneecaps! participants provided consent and participated in interviews (12 females; mean [SD] age 14.9 [2.4] years). Overall, most adolescents responded positively when discussing their experience, such as improvements in their knee pain and satisfaction with how the study was run. Major themes that were generated from the analysis and feedback were: (1) shoe inserts require little effort to use; (2) perceptions of the program were generally positive; (3) participation in the trial could be made easier; (4) warm weather matters; and (5) life happens. Conclusion Adolescents with PFP who participated in the HAPPi Kneecaps! study found that shoe inserts were easy to wear. Most adolescents experienced an improvement in their symptoms and enhanced participation in sport and exercise. Adolescents with PFP prefer an option for warmer climates (e.g. flip flops or sandals), access to online logbooks, and clinicians who are easily accessible. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12619000957190. Date registered: 8/07/2019.

Introduction: The aim of this study was to determine whether participant characteristics and clinical assessments could identify radiographic osteoarthritis (OA) in individuals with clinically diagnosed, symptomatic patellofemoral osteoarthritis (PFOA). Methods: Participant characteristics and clinical assessments were obtained from 179 individuals aged 50 years and over with clinically diagnosed symptomatic PFOA, who were enrolled in a randomised trial. Anteroposterior, lateral, and skyline X-rays were taken of the symptomatic knee. The presence of radiographic PFOA was defined as "no or early PFOA" (Kellgren and Lawrence [KL] grade ≤1 in the PF compartment) or "definite PFOA" (KL grade ≥2). Diagnostic test statistics were applied to ascertain which participant characteristics and clinical assessments could identify the presence of definite radiographic PFOA. Results: A total of 118 participants (66%) had definite radiographic PFOA. Univariate analysis identified that older age (>61 years), female sex, higher body mass index (BMI) (>29 kg/m 2), longer pain duration (>2.75 years), higher maximum knee pain during stair ambulation (>47/100 mm), and fewer repeated single step-ups to pain onset (<21) were associated with the presence of definite radiographic PFOA. Multivariate logistic regression indicated that BMI, pain duration, and repeated single stepups to pain onset were independently associated with radiographic PFOA and identified the presence of definite radiographic PFOA with an overall accuracy of 73%. Conclusion: In individuals over 50 years of age with a clinical diagnosis of PFOA, higher BMI, longer pain duration, and fewer repeated single step-ups to pain onset increased the likelihood of radiographic PFOA. However, overall diagnostic accuracy was modest, suggesting that radiographic PFOA cannot be confidently identified using these tests.

Background: Patellofemoral pain (PFP) affects one-third of adolescents and can persist into adulthood, negatively impacting health and quality of life. Foot orthoses are a recommended treatment for adults with PFP, but have not been evaluated in adolescents. The primary objective was to determine the feasibility of conducting a full-scale randomised controlled trial (RCT) evaluating effects of contoured, prefabricated foot orthoses on knee pain severity and patient-perceived global change, compared to flat insoles. The secondary objective was to describe outcomes on a range of patient-reported outcome measures. Methods: We recruited adolescents aged 12-18 years with PFP of ³2 months duration into a double-blind, randomised, parallel-group feasibility trial. Participants were randomised to receive prefabricated contoured foot orthoses or flat shoe insoles, and followed for 3 months. Participants and outcome assessors were blinded to group allocation. Primary outcomes were feasibility of a full-scale RCT (number of eligible/enrolled volunteers; recruitment rate; adherence with the intervention and logbook completion; adverse effects; success of blinding; drop-out rate), and credibility and expectancy of interventions. Secondary outcomes were patient-reported measures of pain, symptoms, function, quality of life, global rating of change, patient acceptable symptom state, and use of co-interventions.Results: 36 out of 279 (12.9%) volunteers (27 female, mean (SD) age 15 (2) years, body mass 60 (13) kg) were eligible and enrolled, at a recruitment rate of 1.2 participants/week. 17 participants were randomised to receive foot orthoses, and 19 to flat insoles. 15 participants returned logbooks; 7/15 (47%) adhered to the intervention. No serious adverse events were reported. 28% (10/36, 4 pandemic-related) of participants dropped out before 3 months. Blinding was successful. Both groups found the inserts to be credible. Conclusions: Based on a priori criteria for feasibility, findings suggest that a full-scale RCT comparing contoured foot orthoses to flat insoles in adolescents with PFP would not be feasible using the current protocol. Prior to conducting a full-scale RCT, further feasibility studies are needed, with protocol modifications to facilitate participant retention, logbook completion and shoe insert wear. Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12619000957190. Date registered: 8/07/2019.