Self-efficacy and Emotional Distress in a Cohort With Patellofemoral Pain.

Background: Patellofemoral pain (PFP) is commonly described and approached in biomechanical terms despite strong evidence that psychosocial factors such as kinesiophobia, emotional distress, and self-efficacy are important in long-standing musculoskeletal pain. Purpose: To describe levels of self-efficacy, emotional distress, kinesiophobia, and widespread pain in a cohort with long-standing PFP and determine their association with measures of pain, function, and health-related quality of life. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included were 112 patients with PFP (age range, 16-40 years) who had been recruited to a randomized controlled trial. Seven baseline factors (patient sex, pain duration, number of pain sites throughout the body, kinesiophobia [Tampa Scale of Kinesiophobia], emotional distress [Hopkins Symptom Checklist], self-efficacy, and knee extension strength) were investigated for associations with the following outcomes: symptoms of PFP (Anterior Knee Pain Scale), pain (worst and usual), and health-related quality of life (5-level EuroQol-5 Dimensions [EQ-5D-5L]). We used bivariate models and multivariable linear regression models with a stepwise backward removal method to find associations with the outcomes. Internal validation was conducted, and adjusted coefficients after shrinkage are presented. Results: Of the study patients, 28% reported emotional distress (Hopkins Symptom Checklist ≥1.75), 69% reported multiple pain sites, and 33% had widespread pain. The kinesiophobia score was elevated, with a mean score of 35.4 ± 8.2. Self-efficacy was strongly associated with better function (Anterior Knee Pain Scale) and health-related quality of life (EQ-5D-5L) as well as lower pain scores in bivariate and multivariable models. Self-efficacy and emotional distress explained 50% of the variance in health-related quality of life (EQ-5D-5L). Conclusion: Our findings support other studies of PFP suggesting elevated levels of kinesiophobia and emotional distress and higher rates of widespread pain compared with the general population or pain-free controls. Higher self-efficacy was associated with better function and health-related quality of life. Together with emotional distress, it explained half the variance of health-related life quality. The results underline the importance of approaching these patients in a biopsychosocial model. Registration: NCT02114294 (ClinicalTrials.gov identifier).

The reliability, validity, interpretability, and responsiveness of the Norwegian version of the Anterior Knee Pain Scale in patellofemoral pain.

PURPOSE: To determine the reliability, validity, responsiveness, and interpretability of the Norwegian Anterior Knee Pain Scale (AKPS) in patients with patellofemoral pain (PFP). METHODS: The AKPS was translated into Norwegian. One hundred and twelve patients with PFP participated in a randomized controlled trial. Fifty stable patients completed the AKPS at a one-week interval for test-retest reliability. Smallest detectable change (SDC) and floor/ceiling effects were evaluated. Validity and responsiveness were assessed using hypothesis testing for correlations with other scores and known-group validity. Minimal important change (MIC) and responsiveness were evaluated at three months. RESULTS: Intraclass correlation coefficient (ICCagreement) for sum score was 0.83. Smallest detectable change was 13. No floor/ceiling effects were found for total score, but ceiling effects were found on eight of 13 individual items. Hypothesis testing for construct validity and responsiveness was largely confirmed but correlations were moderate to low. The MIC was 11. Area under receiver operating characteristic curve was 0.66 (95% CI 0.56-0.77) indicating moderate responsiveness. CONCLUSIONS: The Norwegian AKPS had comparable measurement properties to other versions, with acceptable reliability and construct validity. We found moderate responsiveness which may be related to ceiling effects on several items.Implications for rehabilitationThe Anterior Knee Pain Scale (AKPS) is a commonly used outcome measure in patellofemoral pain, having acceptable reliability and moderate responsiveness.A change in AKPS total score of 11 points would be considered important by the patient, although changes up to 13 points may be due to measurement error.The AKPS has limitations including ceiling effects on most individual items in this patient population, and low correlation between pain and AKPS that questions the validity of the score. A revision of the score should be considered.

Predictors of Pain, Function, and Change in Patellofemoral Pain.

BACKGROUND: Identification of factors predictive of outcome and change is important to improve treatment for patellofemoral pain (PFP). Few studies have examined the predictive value of psychological factors in PFP, although they have been reported to be important predictors in other musculoskeletal pain conditions. PURPOSE: To evaluate predictors of pain, function, and change 1 year after an exercise-based intervention in PFP. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: In sum, 112 patients were recruited to a randomized controlled trial; 98 attended 1-year follow-up. There were no between-group differences in the trial; thus, the material was analyzed as 1 cohort. Nine baseline factors-sex, bilateral pain, worst pain, pain duration, Anterior Knee Pain Scale (AKPS), kinesiophobia, anxiety and depression, self-efficacy, and number of pain sites throughout the body-were investigated for their predictive ability on outcome at 1 year (AKPS, worst pain) and for change at 1 year (global change score, change in AKPS, and change in worst pain). Multivariable linear regression models with stepwise backward removal method were used to find predictors of poor outcome. RESULTS: Number of pain sites at baseline was a significant predictor of worse outcome for AKPS (B = -2.7; 95% CI, -4.0 to -1.3; P < .01), worst pain (B = 0.5; 95% CI, 0.2-0.8; P < .01), global change (B = -0.8; 95% CI, -1.2 to -0.5; P < .01), change in AKPS (B = -2.7; 95% CI, -4.0 to -1.3; P < .01), and change in worst pain (B = 0.5, 95% CI, 0.2-0.8; P < .01) at 1 year. Baseline scores for AKPS and worst pain predicted respective 1-year levels and change scores (P < .01). Lower self-efficacy and male sex predicted less global change (P < .01). Longer pain duration predicted final score and change score for worst pain (P < .01). The predictive models had reasonable fit with adjusted R2 from 0.22 to 0.35. CONCLUSION: Higher number of pain sites throughout the body was a consistent predictor of poor outcome and less change at 1 year. Baseline levels for AKPS and worst pain predicted respective final scores and change scores. REGISTRATION: NCT02114294 ( ClinicalTrials.gov identifier).

Patellofemoral pain: One year results of a randomized trial comparing hip exercise, knee exercise, or free activity.

OBJECTIVE: Extended follow-up of a randomized trial comparing hip-focused exercise, knee-focused exercise, and free physical activity in patellofemoral pain (PFP). METHODS: A single-blind randomized controlled trial included 112 patients aged 16-40 years (mean 27.6 years) with a clinical diagnosis of PFP ≥3 months (mean 39 months) and pain ≥3/10 on a Visual Analog Scale. Patients were randomized to a 6-week exercise-based intervention consisting of either isolated hip-focused exercises (n = 39), traditional knee-focused exercise (n = 37), or free physical activity (n = 36). All patients received the same patient education. The primary outcome measure was the Anterior Knee Pain Scale (AKPS, 0-100). Secondary outcomes were usual and worst pain, Tampa Scale of Kinesiophobia, Knee Self-Efficacy Score, Euro-Qol (EQ-5D-5L), step-down test, and isometric strength. Blinded observers assessed outcomes at baseline, 3, and 12 months. The study was designed to detect a difference in AKPS >10 at 12 months. RESULTS: After 1 year, there were no significant between-group differences in any primary or secondary outcomes. Between-group differences for AKPS were as follows: knee versus free physical activity -4.3 (95% CI -12.3 to 3.7); hip versus free physical activity -1.1 (95% CI -8.9 to 6.7); and hip versus Knee 3.2 (95% CI -4.6 to 11.0). The cohort as a whole improved significantly at 3 and 12 months compared to baseline for all measures except for knee extension strength. CONCLUSION: After 1 year, there was no difference in effectiveness of knee exercise, hip exercise, or free physical activity, when combined with patient education in PFP.

Effectiveness of Isolated Hip Exercise, Knee Exercise, or Free Physical Activity for Patellofemoral Pain: A Randomized Controlled Trial.

BACKGROUND: Exercise for patellofemoral pain (PFP) is traditionally knee focused, targeting quadriceps muscles. In recent years, hip-focused exercise has gained popularity. Patient education is likely an important factor but is underresearched. PURPOSE: To compare 3 treatment methods for PFP, each combined with patient education: hip-focused exercise, knee-focused exercise, or free physical activity. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A single-blind randomized controlled trial was performed with 112 patients who were 16 to 40 years old (mean, 27.6 years) and had a symptom duration >3 months (mean, 39 months) with a clinical diagnosis of PFP and no radiograph or magnetic resonance evidence of other pathology. Patients were randomized to a 6-week intervention consisting of patient education combined with isolated hip-focused exercise (n = 39), traditional knee-focused exercise (n = 37), or free physical activity (n = 36). The primary outcome was Anterior Knee Pain Scale (0-100) at 3 months. Secondary outcomes were visual analog scale for pain, Tampa Scale for Kinesiophobia, Knee Self-efficacy Scale, EuroQol, step-down, and isometric strength. RESULTS: There were no between-group differences in any primary or secondary outcomes at 3 months except for hip abduction strength and knee extension strength. Between-group differences at 3 months for Anterior Knee Pain Scale were as follows: knee versus control, 0.2 (95% CI, -5.5 to 6.0); hip versus control, 1.0 (95% CI, -4.6 to 6.6); and hip versus knee, 0.8 (95% CI, -4.8 to 6.4). The whole cohort of patients improved for all outcomes at 3 months except for knee extension strength. CONCLUSION: The authors found no difference in short-term effectiveness in combining patient education with knee-focused exercise, hip-focused exercise, or free training for patients with PFP. REGISTRATION: NCT02114294 (ClinicalTrials.gov identifier).

Study protocol: a randomised controlled trial comparing the long term effects of isolated hip strengthening, quadriceps-based training and free physical activity for patellofemoral pain syndrome (anterior knee pain).

BACKGROUND: Patellofemoral pain syndrome (PFPS), also known as Anterior Knee Pain, is a common cause of recurrent or chronic knee pain. The etiology is considered to be multifactorial but is not completely understood. At the current time the leading theory is that pathomechanics in the patellofemoral joint leads to PFPS. Traditionally, conservative treatment has focused on improving strength and timing in the quadriceps muscles. In recent years, evidence has been accumulating to support the importance of hip control and strengthening in PFPS. Two recent studies have shown promising results for hip strengthening as an isolated treatment for PFPS. The aim of this randomised controlled trial (RCT) is to compare isolated hip strengthening to traditional quadriceps-based training and a control group with free physical activity. METHODS/DESIGN: An observer-blinded RCT will be performed. We intend to include 150 patients aged 16-40 years, referred from primary care practitioners to the department of Physical Medicine and Rehabilitation in Kristiansand, Norway for PFPS with more than three months duration. Patients meeting the inclusion criteria will be randomised using opaque sequentially numbered sealed envelopes to one of three groups: isolated hip strengthening, quadriceps based training, or a control group (free physical activity). All groups will receive standardized information about PFPS formulated with the intention to minimize fear avoidance and encourage self-mastery of symptoms. Standardized exercises will be performed under supervision of a study physiotherapist once per week in addition to home training two times per week for a total of six weeks. The primary outcome measure will be the Anterior Knee Pain Score (AKPS) at three and 12 months. Secondary outcome measures will include Visual analogue scale (VAS) for pain, hip abductor and quadriceps strength, the generic EuroQol (EQ-5D), Hopkins Symptom Checklist (HSCL), Knee self-efficacy score and Tampa score for Kinesiophobia. DISCUSSION: This trial will help to elucidate the role of hip and quadriceps strengthening in the treatment of PFPS. Information as to the role of anxiety and depression, kinesiophobia and self-efficacy will be collected, also as regards prognosis and response to exercise therapy. TRIAL REGISTRATION: ClinicalTrials.gov reference: NCT02114294.