Effect of a Psychologically Informed Intervention to Treat Adolescents With Patellofemoral Pain: A Randomized Controlled Trial.

OBJECTIVE: To determine whether the addition of a brief psychologically informed video to traditional physical therapy influenced function (primary aim), pain, and psychological beliefs (secondary aims) among adolescents with patellofemoral pain (PFP). DESIGN: Double-blind randomized controlled trial. SETTING: Outpatient physical therapy clinics of a single pediatric hospital. PARTICIPANTS: Sixty-six adolescents with PFP (14.8±1.7 years old, 65% female). INTERVENTION: Adolescents were randomly assigned to view a brief psychologically informed video (n=34) or control video (n=32). The psychologically informed video targeted pain-related fear and pain catastrophizing, and the control video related basic anatomy and factors involved in PFP. MAIN OUTCOME MEASURES: The primary outcome was change in function (Anterior Knee Pain Scale). Secondary outcomes were change in psychological beliefs (fear-avoidance beliefs, kinesiophobia, pain catastrophizing) and pain. Outcomes were assessed at baseline, immediately post intervention, at 2 weeks, at 6 weeks, and at 3 months. RESULTS: Using a 2-way mixed analysis of variance, change in function in the intervention group was greater than the control group, with a moderate treatment effect noted (P=.001, partial η2=0.1). Post hoc testing revealed that there was a significant interaction between the intervention and time from baseline to 2 weeks, but no interaction was noted between 2 weeks and 3 months. The psychologically informed video significantly reduced maladaptive psychological beliefs (P=.01, η2=0.32). No significant between-group differences in pain were noted. CONCLUSIONS: Incorporating a brief one-time psychologically informed video into standard physical therapy care significantly reduced pain-related fear, reduced pain catastrophizing, and improved function among adolescents with PFP. The immediate effect noted on function did not continue throughout the course of care.

Immediate Effect of Ankle Mobilization on Range of Motion, Dynamic Knee Valgus, and Knee Pain in Women With Patellofemoral Pain and Ankle Dorsiflexion Restriction: A Randomized Controlled Trial With 48-Hour Follow-Up.

CONTEXT: Restriction in ankle dorsiflexion range of motion (ROM) has been previously associated with excessive dynamic knee valgus. This, in turn, has been correlated with knee pain in women with patellofemoral pain. OBJECTIVES: To investigate the immediate effect of 3 ankle mobilization techniques on dorsiflexion ROM, dynamic knee valgus, knee pain, and patient perceptions of improvement in women with patellofemoral pain and ankle dorsiflexion restriction. DESIGN: Randomized controlled trial with 3 arms. SETTING: Biomechanics laboratory. PARTICIPANTS: A total of 117 women with patellofemoral pain who display ankle dorsiflexion restriction were divided into 3 groups: ankle mobilization with anterior tibia glide (n = 39), ankle mobilization with posterior tibia glide (n = 39), and ankle mobilization with anterior and posterior tibia glide (n = 39). INTERVENTION(S): The participants received a single session of ankle mobilization with movement technique. MAIN OUTCOME MEASURES: Dorsiflexion ROM (weight-bearing lunge test), dynamic knee valgus (frontal plane projection angle), knee pain (numeric pain rating scale), and patient perceptions of improvement (global perceived effect scale). The outcome measures were collected at the baseline, immediate postintervention (immediate reassessment), and 48 hours postintervention (48 h reassessment). RESULTS: There were no significant differences between the 3 treatment groups regarding dorsiflexion ROM and patient perceptions of improvement. Compared with mobilization with anterior and posterior tibia glide, mobilization with anterior tibia glide promoted greater increase in dynamic knee valgus (P = .02) and greater knee pain reduction (P = .02) at immediate reassessment. Also compared with mobilization with anterior and posterior tibia glide, mobilization with posterior tibia glide promoted greater knee pain reduction (P < .01) at immediate reassessment. CONCLUSION: In our sample, the direction of the tibia glide in ankle mobilization accounted for significant changes only in dynamic knee valgus and knee pain in the immediate reassessment.

Added Value of Gluteus Medius and Quadratus Lumborum Dry Needling in Improving Knee Pain and Function in Female Athletes With Patellofemoral Pain Syndrome: A Randomized Clinical Trial.

OBJECTIVE: To compare the effects of exercise therapy alone and exercise therapy plus gluteus medius (GM) and quadratus lumbarum (QL) dry needling on pain and function in female athletes with patellofemoral pain (PFP). DESIGN: Single-blind randomized controlled trial with follow-up. SETTING: Physiotherapy clinic. PARTICIPANTS: Convenience sample of female athletes with PFP (N=40), who were randomly assigned to the exercise therapy (Ex group) or exercise-therapy+dry needling (Ex+DN group) group. INTERVENTIONS: The Ex group received exercise therapy for 4 weeks, and the Ex+DN group received exercise therapy in combination with dry needling directed at GM and QL trigger points for 4 weeks. MAIN OUTCOME MEASURES: In all participants, pain intensity, function (Kujala score, modified star excursion balance test, step-down test), and QL and GM pressure pain threshold (PPT) were recorded at baseline and at 4 and 6 weeks after the start of treatment. Analysis of variance (2 groups×3 times) was used to compare within- and between-group differences. RESULTS: The group versus time interaction effect was significant for all variables (P<.05). Both groups showed significant improvements in pain, function, and PPT at weeks 4 and 6 compared to baseline (P<.05). Between-groups comparisons showed significantly greater improvements in pain, function, and PPT in the Ex+DN group (P<.05). CONCLUSIONS: Targeting intervention to treat trigger points in the GM and QL muscles combined with exercise therapy had superior beneficial effects compared to exercise alone in managing PFP. Therefore, adding GM and QL muscle dry needling to exercise therapy may be advisable to enhance the effects of PFP rehabilitation.

Two Weeks of Wearing a Knee Brace Compared With Minimal Intervention on Kinesiophobia at 2 and 6 Weeks in People With Patellofemoral Pain: A Randomized Controlled Trial.

OBJECTIVE: To investigate the effect of a knee brace compared with minimal intervention on self-reported kinesiophobia and function, objective function, and physical activity level in people with patellofemoral pain (PFP). DESIGN: Single-blind randomized controlled trial (1:1), parallel. PARTICIPANTS: Individuals with PFP (N=50). MAIN OUTCOME MEASURES: Primary: kinesiophobia (Tampa Scale for Kinesiophobia). Secondary: self-reported function (Anterior Knee Pain Scale), physical activity level (International Physical Activity Questionnaire), and objective function (forward step-down test). Outcomes were assessed at baseline (T0), at the end of the intervention (2wk) (T1), and at 6 weeks after baseline (T2). INTERVENTION: Participants were randomly assigned to 1 of 2 interventions groups: (1) use of knee brace for 2 weeks during daily living, sports, or painful tasks (brace group) and (2) educational leaflet with information about PFP (leaflet group). RESULTS: The knee brace reduced kinesiophobia in people with PFP compared with minimal intervention with moderate effect size at T1=mean difference (95% CI) -5.56 (-9.18 to -1.93) and T2=-5.24 (-8.58 to -1.89). There was no significant difference in self-reported and objective function and physical activity level. CONCLUSIONS: The knee brace improved kinesiophobia immediately after intervention (at 2wk) and at 6-week follow-up in people with PFP compared with minimal intervention. A knee brace may be considered within clinically reasoned paradigms to facilitate exercise therapy interventions for people with PFP.

Comparison of Protonics™ Knee Brace With Sport Cord on Knee Pain and Function in Patients With Patellofemoral Pain Syndrome: A Randomized Controlled Trial.

CONTEXT: Protonics™ knee brace has been suggested as an intervention for patients with patellofemoral pain syndrome. However, the effectiveness of this knee brace compared with traditional conservative methods knee rehabilitation is lacking. OBJECTIVE: To compare the effect of Protonics™ knee brace versus sport cord on knee pain and function in patients with patellofemoral pain syndrome. DESIGN: Randomized controlled trial. SETTING: Loma Linda University. PARTICIPANTS: There were 41 subjects with patellofemoral pain with a mean age of 28.8 (5.0) years and body mass index of 25.6 (4.7) kg/m2 participated in the study. INTERVENTION: Subjects were randomized to 1 of 2 treatment groups, the Protonics™ knee brace (n = 21) or the sport cord (n = 20) to complete a series of resistance exercises over the course of 4 weeks. MAIN OUTCOME MEASURES: Both groups were evaluated according to the following clinical outcomes: anterior pelvic tilt, hip internal/external rotation, and iliotibial band flexibility. The following functional outcomes were also assessed: Global Rating of Change Scale, the Kujala score, the Numeric Pain Rating Scale, and the lateral step-down test. RESULTS: Both groups showed significant improvement in the outcome measures. However, the Protonics™ knee brace was more effective than the sport cord for the Global Rating of Change Scale over time (immediate 1.0 [2.1] vs post 2 wk 3.0 [2.2] vs 4 wk 4.6 [2.3] in the Protonics™ brace compared with 0.0 [2.1] vs 1.3 [2.2] vs 3.0 [2.3] in the sport cord, P < .01), suggesting greater satisfaction. CONCLUSIONS: Both study groups had significant improvements in the clinical and functional symptoms of patellofemoral pain. The Protonics™ knee brace group was significantly more satisfied with their outcome. However, the sport cord may be a more feasible and cost-effective method that yields similar results in patients with patellofemoral pain syndrome.

Effects of Posterior X Taping on Movement Quality and Knee Pain Intensity during Forward-Step-Down in Patients with Patellofemoral Pain Syndrome.

Excessive tibiofemoral rotation in weight-bearing position may be associated with patellofemoral pain syndrome (PFPS). A previous literature suggested that "posterior X taping" method is effective for correcting the reduction of hip adduction and tibiofemoral rotation in weight bearing position. The purpose of this study was to determine the effects of posterior X taping on the angles of hip adduction, tibiofemoral rotation, grades of the forward-step-down (FSD) performance test, and intensity of knee pain when descending stair in patients with PFPS. We recruited patients with PFPS. The knee pain intensity during FSD was measured using visual analogue scale system (100 mm) under both no-tape and tape conditions. A three-dimensional motion analysis system was used to assess the kinematics of lower limb joints during FSD. In addition, scoring system of FSD performance test was used to assess the movement deviation of the trunk and lower limb and one-leg balance. Participants with PFPS showed reduced pain intensity (p = 0.001) and improved scores on FSD performance test (p = 0.002) with posterior X taping compared to the no-tape condition during FSD. No significant alterations changes were noted in three dimensional angles of the hip, knee and ankle joints, especially hip adduction and tibiofemoral rotation between conditions. Posterior X taping decreases knee pain and improves the scores on FSD performance test for patients with PFPS.

Added Value of Isolated Core Postural Control Training on Knee Pain and Function in Women With Patellofemoral Pain Syndrome: A Randomized Controlled Trial.

OBJECTIVES: To evaluate the added value of isolated core postural control training on knee pain and function in women with patellofemoral pain syndrome (PFPS). DESIGN: Randomized controlled trial. SETTING: Rehabilitation sciences research center. PARTICIPANTS: Women (N=33) between 18 and 30 years of age with PFPS were randomly assigned to a control group (n=16) or the experimental group (n=17). INTERVENTIONS: Participants in both groups received the same stretching and strengthening exercises during 4 weeks (12 sessions 3 days per week). The experimental group also received isolated core postural training with an unstable seat apparatus. MAIN OUTCOME MEASURES: Center of pressure (CoP) trajectories in sitting postural control, pain intensity, and function were recorded before and after the 4-week intervention period. Functional capacity and pain intensity were reassessed 3 months after the intervention. RESULTS: After treatment, both groups had significant improvements in pain, function (P<.001), and CoP trajectories in sitting postural control (control group P<.05, experimental group P<.001). Between-group comparisons demonstrated greater improvements in pain, function, and CoP trajectories in the experimental group (P<.001). This group also had significantly greater improvements in pain and Kujala Anterior Knee Pain Scale score at 3-month follow-up compared to the control group (P<.001). CONCLUSIONS: Adding isolated core postural control training to physiotherapy exercises was associated with significantly greater improvements in pain, function, and CoP trajectories than physiotherapy exercises alone. Therefore, unstable sitting postural control training is potentially useful to enhance rehabilitation management in patients with PFPS.

Use of Wearables: Tracking and Retraining in Endurance Runners.

Wearable devices are ubiquitous among runners, coaches, and clinicians with an ever-increasing number of devices coming on the market. In place of gold standard measures in the laboratory, these devices attempt to provide a surrogate means to track running biomechanics outdoors. This review provides an update on recent literature in the field of wearable devices in runners, with an emphasis on criterion validity and usefulness in the coaching and rehabilitation of runners. Our review suggests that while enthusiasm should be tempered, there is still much for runners to gain with wearables. Overall, our review finds evidence supporting the use of wearables to improve running performance, track global training loads applied to the runner, and provide real-time feedback on running speed and run cadence. Case studies illustrate the use of wearables for the purposes of performance and rehabilitation.

The effects of joint mobilization on individuals with patellofemoral pain: a systematic review.

OBJECTIVE: To investigate and synthesize the effects of joint mobilization on individuals with patellofemoral pain syndrome. DATA SOURCES: Five electronic databases (CINAHL, the Cochrane Central Register of Controlled Trials, PubMed, Scopus, and SPORTDiscus) were used. REVIEW METHODS: Each database was searched from inception to 1 November 2017. Randomized controlled trials investigating a manual therapy intervention, with or without co-interventions, for persons with patellofemoral pain were included. Two reviewers independently screened the retrieved literature and appraised the quality of the selected studies using the PEDro rating scale. A third reviewer was used in cases of discrepancy to create a consensus. RESULTS: A total of 361 articles were identified in the search. Twelve randomized trials with a total of 499 participants were selected for full review. Within-group improvements in pain and function were noted for the manual therapy groups. Between-group improvements for short-term outcomes (three months or less) were greatest when joint mobilization was directed to the knee complex and used as part of a comprehensive approach. CONCLUSION: In the articles reviewed, joint mobilization appears to be most effective in improving pain and function when coupled with other interventions, although its discrete effect is unclear due to the reviewed studies' design and reporting.

A sequential cognitive and physical approach (SCOPA) for patellofemoral pain: a randomized controlled trial in adolescent patients.

OBJECTIVE:: To compare a sequential treatment algorithm considering psychosocial and physical impairments, with a conventional rehabilitation approach considering only physical impairments in adolescents with patellofemoral pain. DESIGN:: A randomized, single-blind, controlled study. PARTICIPANTS:: Fifty-five adolescents (36 females; mean age 14.3 ± 1.8 years). INTERVENTIONS:: The sequential cognitive and physical approach (SCOPA) group ( n = 28) was treated based on sequential testing and treatment of activity-related fear, flexibility, kinematics, and strength. The comparator group ( n = 27) was treated with a non-sequential physical impairment-based approach. Both groups received treatment two times a week for up to six weeks. MEASUREMENTS:: Function (Anterior Knee Pain Scale), pain (Numeric Pain Rating Scale), and Global Rating of Change were assessed at baseline, three weeks, and six weeks, with a six-month follow-up. RESULTS:: Both groups had similar function (73.7 ± 9.6) and pain (6.0 ± 2.3) at baseline. A third of individuals with patellofemoral pain demonstrated elevated activity-related fear at baseline. Patients randomized to the SCOPA group had clinically significant greater improvements at six weeks in function (SCOPA, 95.0 ± 7.4 and comparator, 84.8 ± 10.4; mean difference: 10.2, 95% CI: 5.3, 15.1) and pain (SCOPA, 0.9 ± 1.9 and comparator, 2.7 ± 2.1; mean difference: 1.7, 95% CI: 0.5, 2.9). No differences were noted in Global Rating of Change. No between-group differences were noted in any outcome at six-month follow-up. CONCLUSION:: The sequential cognitive and physical approach resulted in greater improvements in short-term function and pain. By six months, both groups demonstrated similar clinically significant improvements in all outcomes.

A feasibility study of a novel, task-specific movement training intervention for women with patellofemoral pain.

OBJECTIVE: To investigate whether a novel, task-specific training intervention that focused on correcting pain-producing movement patterns was feasible and whether it would improve hip and knee kinematics, pain, and function in women with patellofemoral pain. DESIGN: Prospective, non-randomized, within-group, double baseline, feasibility intervention study. SUBJECTS: A total of 25 women with patellofemoral pain were enrolled. INTERVENTION: The intervention, delivered 2×/week for six weeks, consisted of supervised, high-repetition practice of daily weight-bearing and recreational activities. Activities were selected and progressed based on participants' interest and ability to maintain optimal alignment without increasing pain. MAIN MEASURES: Primary feasibility outcomes were recruitment, retention, adherence, and treatment credibility (Credibility/Expectancy Questionnaire). Secondary outcomes assessing intervention effects were hip and knee kinematics, pain (visual analog scale: current, average in past week, maximum in past week), and function (Patient-Specific Functional Scale). RESULTS: A total of 25 participants were recruited and 23 were retained (92% retention). Self-reported average daily adherence was 79% and participants were able to perform their prescribed home program correctly (reduced hip and knee frontal plane angles) by the second intervention visit. On average, treatment credibility was rated 25 (out of 27) and expectancy was rated 22 (out of 27). Hip and knee kinematics, pain, and function improved following the intervention when compared to the control phase. CONCLUSION: Based on the feasibility outcomes and preliminary intervention effects, this task-specific training intervention warrants further investigation and should be evaluated in a larger, randomized clinical trial.

Is combining gait retraining or an exercise programme with education better than education alone in treating runners with patellofemoral pain?A randomised clinical trial.

DESIGN: Single-blind randomised clinical trial. OBJECTIVE: To compare the effects of three 8-week rehabilitation programmes on symptoms and functional limitations of runners with patellofemoral pain (PFP). METHODS: Sixty-nine runners with PFP were randomly assigned to one of three intervention groups: (1) education on symptoms management and training modifications (education); (2) exercise programme in addition to education (exercises); (3) gait retraining in addition to education (gait retraining). Symptoms and functional limitations were assessed at baseline (T0), and after 4, 8 and 20 weeks (T4, T8 and T20) using the Knee Outcome Survey of the Activities of Daily Living Scale (KOS-ADLS) and visual analogue scales (VASs) for usual pain, worst pain and pain during running. Lower limb kinematics and kinetics during running, and isometric strength were also evaluated at T0 and T8. The effects of rehabilitation programmes were assessed using two-way analysis of variance. RESULTS: No significant group × time interactions (p<0.447) were found for KOS-ADLS and VASs. All three groups showed similar improvements at T4, T8 and T20 compared with T0 (p<0.05). Only the exercises group increased knee extension strength following rehabilitation (group × time: p<0.001) and only the gait retraining group (group × time: p<0.001) increased step rate (+7.0%) and decreased average vertical loading rate (-25.4%). CONCLUSION: Even though gait retraining and exercises improved their targeted mechanisms, their addition to education did not provide additional benefits on symptoms and functional limitations. Appropriate education on symptoms and management of training loads should be included as a primary component of treatment in runners with PFP. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT02352909).

The Application of Blood Flow Restriction: Lessons From the Laboratory.

Blood flow restriction by itself or in combination with exercise has been shown to produce beneficial adaptations to skeletal muscle. These adaptations have been observed across a range of populations, and this technique has become an attractive possibility for use in rehabilitation. Although there are concerns that applying blood flow restriction during exercise makes exercise inherently more dangerous, these concerns appear largely unfounded. Nevertheless, we have advocated that practitioners could minimize many of the risks associated with blood flow-restricted exercise by accounting for methodological factors, such as cuff width, cuff type, and the individual to which blood flow restriction is being applied. The purpose of this article is to provide an overview of these methodological factors and provide evidence-based recommendations for how to apply blood flow restriction. We also provide some discussion on how blood flow restriction may serve as an effective treatment in a clinical setting.

Effects of Anterior Knee Displacement During Squatting on Patellofemoral Joint Stress.

CONTEXT: Squatting is a common rehabilitation training exercise for patellofemoral pain syndrome (PFPS). Patellofemoral joint stress (PFJS) during squatting with more anterior knee displacement has not been systematically investigated. OBJECTIVE: To compare PFJS during squatting using 2 techniques: squat while keeping the knees behind the toes (SBT) and squat while allowing the knees to go past the toes (SPT). SETTING: University research laboratory. PARTICIPANTS: Twenty-five healthy females (age: 22.69 (0.74) y; height: 169.39 (6.44) cm; mass: 61.55 (9.74) kg) participated. MAIN OUTCOME MEASURES: Three-dimensional kinematic and kinetic data were collected at 180 and 1800 Hz, respectively. A musculoskeletal model was used to calculate muscle forces through static optimization. These muscle forces were used in a patellofemoral joint model to estimate PFJS. RESULTS: The magnitudes of PFJS, reaction force, and quadriceps force were higher (P < .001) during SPT compared with the SBT technique. Knee flexion, hip flexion, and ankle dorsiflexion angles were reduced when using the SBT technique. CONCLUSIONS: Findings provide some general support for minimizing forward knee translation during squats for patients that may have patellofemoral pain syndrome.

Vastus Medialis Hoffmann Reflex Excitability Is Associated With Pain Level, Self-Reported Function, and Chronicity in Women With Patellofemoral Pain.

OBJECTIVE: To determine the association between the amplitude of vastus medialis (VM) Hoffmann reflex (H-reflex) and pain level, self-reported physical function, and chronicity of pain in women with patellofemoral pain (PFP). DESIGN: Cross-sectional study. SETTING: Laboratory of biomechanics and motor control. PARTICIPANTS: Women diagnosed with PFP (N=15) aged 18 to 35 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Data on worst pain level during the previous month, self-reported physical function, and symptom duration (chronicity) were collected from the participants. Maximum evoked responses were obtained by electrical stimulation applied to the femoral nerve and peak-to-peak amplitudes of normalized maximal H-reflexes (maximal Hoffmann reflex/maximal motor wave ratios) of the VM were calculated. A Pearson product-moment correlation matrix (r) was used to explore the relations between the amplitude of VM H-reflex and worst pain during the previous month, self-reported function, and chronicity of pain. RESULTS: Strong negative correlations were found between the amplitude of VM H-reflex and worst pain in the previous month (r=-.71; P=.003) and chronicity (r=-.74; P=.001). A strong positive correlation was found between the amplitude of VM H-reflex and self-reported physical function (r=.62; P=.012). CONCLUSIONS: The strong and significant relations reported in this study suggest that women with PFP showing greater VM H-reflex excitability tend to have lower pain, better physical function, and more recent symptoms. Therefore, rehabilitation strategies designed to increase the excitability of the monosynaptic stretch reflex should be considered in the treatment of women with PFP if their effectiveness is demonstrated in future studies.

Lasting Improvement of Patient-Reported Outcomes 6 Months After Patellofemoral Pain Rehabilitation.

BACKGROUND/OBJECTIVE: Hip- and knee-muscle-strengthening programs are effective in improving short-term patient-reported and disease-oriented outcomes in individuals with patellofemoral pain (PFP), but few to no data exist on moderate- to long-term postrehabilitative outcomes. The first purpose of the study was to assess differences in pain, function, strength, and core endurance in individuals with PFP before, after, and 6 mo after successful hip- or knee-muscle-strengthening rehabilitation. The second purpose was to prospectively follow these subjects for PFP recurrence at 6, 12, and 24 mo postrehabilitation. METHODS: For 24 mo postrehabilitation, 157 physically active subjects with PFP who reported treatment success were followed. At 6 mo postrehabilitation, pain, function, hip and knee strength, and core endurance were measured. At 6, 12, 18, and 24 mo, PFP recurrence was measured via electronic surveys. RESULTS: Sixty-eight subjects (43%) returned to the laboratory at 6 mo. Regardless of rehabilitation program, subjects experienced significant improvements in pain and function, strength, and core endurance pre- to postrehabilitation and maintained improvements in pain and function 6 mo postrehabilitation (Visual Analog Scale/Pain-pre 5.12 ± 1.33, post 1.28 ± 1.14, 6 mo 1.68 ± 2.16 cm, P < .05; Anterior Knee Pain Scale/Function-pre 76.38 ± 8.42, post 92.77 ± 7.36, 6 mo 90.27 ± 9.46 points, P < .05). Over the 24 mo postrehabilitation, 5.10% of subjects who responded to the surveys reported PFP recurrence. CONCLUSIONS: The findings support implementing a hip-or knee-muscle-strengthening program for the treatment of PFP. Both programs improve pain, function, strength, and core endurance in the short term with moderate- and long-term benefits of improved pain and function and low PFP recurrence.

Effects of rehabilitation approaches for runners with patellofemoral pain: protocol of a randomised clinical trial addressing specific underlying mechanisms.

BACKGROUND: Patellofemoral pain (PFP) is highly prevalent in runners, and often leads to functional limitations and cessation of running. Training errors as well as decreased lower limb strength and control during running have all been associated with PFP. While strengthening and gait retraining are commonly used by clinicians, no randomised clinical trial has compared these modalities in runners with PFP. The primary objective of this randomised clinical trial will be to compare the effects of three rehabilitation programs targeting different key factors on symptoms and functional limitations of runners with PFP. The secondary objective will be to explore the factors leading to clinical improvement. METHODS/DESIGN: We will conduct a single-blind randomised clinical trial to compare three different 8 week rehabilitation programs: Group 1 will receive education on symptoms management based on training modifications; Group 2 will receive an exercise program targeting lower limb strengthening and control in addition to the education component of Group 1; Group 3 will receive running gait retraining advice as well as the education component of Group 1. Sixty-nine runners with PFP will be recruited and will be seen by independent physiotherapists on five visits through 8 weeks. The primary outcome measure will be symptoms and functional limitations measured by the Knee Outcome Survey - Activities of Daily Living Scale questionnaire at baseline, and at the four, eight and 20 weeks follow-up. Secondary outcomes will include pain level measured using visual analog scales, and running mileage. Lower limb kinematics and kinetics during running, and isometric strength will also be evaluated at baseline and 8 weeks follow-up. The effects of rehabilitation programs on measures of symptoms and functional limitations will be assessed using a 2-way ANOVA (Groups x Time). Regression analyses will be used to identify if changes in running mechanics or strength are determinants of clinical success. DISCUSSION: Studies with a high level of evidence are needed to determine the best rehabilitation interventions for runners with PFP. This randomised clinical trial will be the first to compare programs targeting different key factors linked with PFP. Results may guide clinicians and improve their clinical outcomes when treating runners with PFP. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02352909. Registered on December 3, 2014.

Factors that predict a poor outcome 5-8†years after the diagnosis of patellofemoral pain: a multicentre observational analysis.

BACKGROUND: Patellofemoral pain (PFP) has traditionally been viewed as self-limiting, but recent studies show that a large proportion of patients report chronic knee pain at long-term follow-up. We identified those patients with an unfavourable recovery ('moderate improvement' to 'worse than ever' measured on a Likert scale) and examined whether there is an association between PFP and osteoarthritis (OA) at 5-8-year follow-up. METHODS: Long-term follow-up data were derived from 2 randomised controlled trials (n=179, n=131). Patient-reported measures were obtained at baseline. Pain severity (100 mm visual analogue scale (VAS)), function (Anterior Knee Pain Scale (AKPS)) and self-reported recovery were measured 5-8 years later, along with knee radiographs. Multivariate backward stepwise linear regression analyses were used to evaluate the prognostic ability of baseline pain duration, pain VAS and AKPS on outcomes of pain VAS and AKPS at 5-8 years. RESULTS: 60 (19.3%) participants completed the questionnaires at 5-8-year follow-up (45 women, mean age at baseline 26 years) and 50 underwent knee radiographs. No differences were observed between responders and non-responders regarding baseline demographics, and 3-month and 12-month pain severity and recovery. 34 (57%) reported unfavourable recovery at 5-8 years. 48 out of 50 participants (98%) had no signs of radiographic knee OA. Multivariate models revealed that baseline PFP duration (>12 months; R(2)=0.22) and lower AKPS (R(2)=0.196) were significant predictors of poor prognosis at 5-8 years on measures of worst pain VAS and AKPS, respectively. SUMMARY AND CONCLUSION: More than half of participants with PFP reported an unfavourable recovery 5-8 years after recruitment, but did not have radiographic knee OA. Longer PFP duration and worse AKPS score at baseline predict poor PFP prognosis. Education of health practitioners and the general public will provide patients with more realistic expectations regarding prognosis.

Comparison of Transcutaneous Electrical Nerve Stimulation and Cryotherapy for Increasing Quadriceps Activation in Patients With Knee Pathologies.

CLINICAL SCENARIO: Proper neuromuscular activation of the quadriceps muscle is essential for maintaining quadriceps (quad) strength and lower-extremity function. Quad activation (QA) failure is a common characteristic observed in patients with knee pathologies, defined as an inability to voluntarily activate the entire alpha-motor-neuron pool innervating the quad. One of the more popular techniques used to assess QA is the superimposed burst (SIB) technique, a force-based technique that uses a supramaximal, percutaneous electrical stimulation to activate all of the motor units in the quad during a maximal, voluntary isometric contraction. Central activation ratio (CAR) is the formula used to calculate QA level (CAR = voluntary force/SIB force) with the SIB technique. People who can voluntarily activate 95% or more (CAR = 0.95-1.0) of their motor units are defined as being fully activated. Therapeutic exercises aimed at improving quad strength in patients with knee pathologies are limited in their effectiveness due to a failure to fully activate the muscle. Within the past decade, several disinhibitory interventions have been introduced to treat QA failure in patients with knee pathologies. Transcutaneous electrical nerve stimulation (TENS) and cryotherapy are sensory-targeted modalities traditionally used to treat pain, but they have been shown to be 2 of the most successful treatments for increasing QA levels in patients with QA failure. Both modalities are hypothesized to positively affect voluntary QA by disinhibiting the motor-neuron pool of the quad. In essence, these modalities provide excitatory afferent stimuli to the spinal cord, which thereby overrides the inhibitory afferent signaling that arises from the involved joint. However, it remains unknown whether 1 is more effective than the other for restoring QA levels in patients with knee pathologies. By knowing the capabilities of each disinhibitory modality, clinicians can tailor treatments based on the rehabilitation goals of their patients. Focused Clinical Question: Is TENS or cryotherapy the more effective disinhibitory modality for treating QA failure (quantified via CAR) in patients with knee pathologies?

The Effects of a Multimodal Rehabilitation Program on Symptoms and Ground-Reaction Forces in Runners With Patellofemoral Pain Syndrome.

CONTEXT: Patellofemoral pain (PFP) is one of the most frequent running-related injuries. However, few interventions taking into consideration the specificity of running have been shown to be effective in runners with PFP. OBJECTIVE: To evaluate the effects of a multimodal rehabilitation program including lower-limb-strengthening/ motor-control exercises, advice on running biomechanics, and symptoms management on symptoms, strength, and ground-reaction forces in runners with PFP. DESIGN: Pre- to post- quasi-experimental. SETTING: Gait-analysis laboratory and private physical therapy clinic. PARTICIPANTS: 21 runners with PFP (34.1 ± 6.0 y old, symptoms duration 38.1 ± 45.5 mo). INTERVENTION: An 8-wk multimodal rehabilitation program including lower-limb- and core-strengthening and motor-control exercises, as well as advice on running gait and symptoms management. MAIN OUTCOME MEASURES: The Activities of Daily Living Scale of the Knee Outcome Survey (KOS-ADLS) questionnaire and visual analog scales for usual pain (VAS-U), worst pain (VAS-W), and pain during running (VAS-R) were used to assess changes in symptoms and function. Vertical ground-reaction forces (VGRF) during running and lower-limb isometric strength were also measured. RESULTS: Statistically and clinically significant improvements (P < .001) were reported on KOS-ADLS (+17.8 pts), VAS-U (-19.2 pts), VAS-W (-28.7 pts), and VAS-R (-32.2 pts) after the intervention. No significant changes in isometric strength were observed. The instantaneous vertical loading rate was decreased after the intervention (P = .002), and this reduction was correlated with changes in KOS-ADLS scores (P = .028). CONCLUSION: This multimodal intervention was successful in reducing pain and improving function of runners with PFP. However, no significant changes in lower-limb strength were observed. It appears that changes in VGRF combined with appropriate training advice could explain the clinical outcomes.