2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: Terminology, definitions, clinical examination, natural history, patellofemoral osteoarthritis and patient-reported outcome measures

Community-based rehabilitation implementation framework to address patellofemoral pain amongst runners in under-resourced communities: Delphi consensus

BACKGROUND

Runners in under-resourced communities in parts of South Africa present with a high prevalence of patellofemoral pain (PFP), which affects their level of participation in sporting activities. Therefore, a specific rehabilitation approach is necessary to manage the PFP-related needs of these runners within their means and reach.

OBJECTIVE

To develop a community-based rehabilitation (CBR) implementation framework for PFP amongst runners in under-resourced communities.

METHOD

Our study used the Delphi technique to develop an appropriate rehabilitation implementation framework for PFP in community-based settings. Sport medicine experts, involved in the treatment and rehabilitation of PFP, were recruited to participate. The Delphi process consisted of three rounds to attain consensus amongst the experts on the components and elements that could be contained in a rehabilitation implementation framework for the management of PFP. Experts rated the framework items using a five-point Likert scale.

RESULTS

A total of 19 experts participated in our study: 10 were females and 9 were males of whom 13 were aged between 36 and 55 years. Most were local experts (15) with 11-20 years of clinical experience. Four core rehabilitation implementation items were identified through the Delphi process. These were: (1) the establishment of transdisciplinary rehabilitation teams, (2) upskilling of available clinicians, their assistants and trainers, (3) implementation of a CBR programme at low-level or no-cost and (4) referral of cases to secondary or tertiary institutions for further management.

CONCLUSION

Consensus was reached for a comprehensive CBR implementation framework aimed at addressing the specific needs of runners with PFP in under-resourced communities.

CLINICAL IMPLICATIONS

A further study to test the feasibility of the agreed-upon intervention is recommended.

Outcomes After Deepening Trochleoplasty and Concomitant Realignment in Patients With Severe Trochlear Dysplasia With Chronic Patellofemoral Pain: Results at 2-Year Follow-up

Background

Abnormal patellofemoral joint stress appears to have major relevance in a subgroup of patients with patellofemoral pain (PFP).

Purpose

To evaluate whether patients with chronic PFP and trochlear dysplasia-induced patellofemoral joint malalignment benefit from a deepening trochleoplasty procedure with the aim of improving patellotrochlear congruence.

Study Design

Case series; Level of evidence, 4.

Methods

Included were 15 patients (male/female, 1/14; mean age, 30.3 years [range, 19-51 years]) with 8.8 years (range, 1-20 years) of chronic PFP and severe trochlear dysplasia. All patients underwent correction of patellotrochlear malalignment with deepening trochleoplasty and concomitant realignment procedures. The Kujala score and a numerical analog scale (0-10) for intensity of pain were used to assess symptoms preoperatively and at 12 and 24 months postoperatively. Pre- and postoperative magnetic resonance imaging (MRI) scans from the patients were compared with the MRI scans of age- and sex-matched controls regarding the patellotrochlear contact area and contact ratio, patellar tilt, patellotrochlear index, and lateral trochlear inclination (LTI) angle.

Results

The Kujala score increased from a mean of 55 (range, 15-81) preoperatively to 82.5 (range, 53-98) after 12 months (95% CI, -42.56 to -12.37; P < .001) and to 84.2 (range, 59-99) after 24 months (95% CI, -44.29 to -14.11; P < .001). The intensity of PFP decreased from 5.7 (range, 3-10) preoperatively to 1.4 (range, 0-4) after 12 months (95% CI, 2.57 to 5.96; P < .001) and had a mean of 1.6 (range, 0-6) after 24 months (95% CI, 2.44 to 5.75; P < .001). Preoperatively, parameters in the study group indicated significant patellotrochlear malalignment, which improved and normalized (except for the LTI angle) postoperatively compared with the values of the control group (P > .05).

Conclusion

In a subgroup of patients with chronic PFP due to severe trochlear dysplasia, deepening trochleoplasty and concomitant realignment procedures significantly reduced pain and improved knee joint function while normalizing patellotrochlear congruence.

Usual Medical Care for Patellofemoral Pain Does Not Usually Involve Much Care: 2-Year Follow-up in the Military Health System

OBJECTIVES

To identify the most common type and timing of interventions used to initially manage patellofemoral pain (PFP), and whether exercise therapy as an initial treatment was associated with a decreased likelihood of recurrence of PFP.

DESIGN

Retrospective cohort.

METHODS

Active-duty military service members (n = 74 408) aged 18 to 50 years and diagnosed with PFP between 2010 and 2011 were included. We identified the type and timing of interventions from electronic medical records and insurance payer claims, and studied the influence of early exercise therapy use on injury recurrence rates.

RESULTS

In this cohort of patients with PFP, 62.3% (n = 46 338) sought no additional care after the initial visit. The most common initial pharmacological interventions were nonsteroidal anti-inflammatory drugs (4.1%), corticosteroid injections (0.4%), and muscle relaxers (0.3%). The most common initial nonpharmacological treatments were exercise therapy (7.6%), passive modalities (eg, hot packs, electrical stimulation, ultrasound; 0.6%), and manual therapy (joint manipulation and mobilization; 0.5%). Common specialty referrals were to physical therapy (3.3%) and orthopaedic providers (0.8%). If patients received at least 6 exercise therapy visits during the initial episode of care, they were less likely to have a recurrence of knee pain (odds ratio = 0.46; 95% confidence interval: 0.42, 0.49).

CONCLUSION

Two in every 3 patients did not seek additional care after PFP diagnosis. For those who sought additional care, exercise therapy was the most common intervention, and higher doses of exercise therapy were associated with a reduced likelihood of having a recurrent episode of knee pain. J Orthop Sports Phys Ther 2021;51(6):305-313. Epub 10 May 2021. doi:10.2519/jospt.2021.10076.

Trunk, Hip and Knee Exercise Programs for Pain Relief, Functional Performance and Muscle Strength in Patellofemoral Pain: Systematic Review and Meta-Analysis

Objective

Previous research suggests that muscle strength exercise is the most effective rehabilitation methods in patients with patellofemoral pain (PFP). This systematic review with meta-analysis compared the effects of Hip&Knee, Hip-only and Knee-only exercise programs on pain relief, muscle strength, and functional performance in patients with PFP.

Methods

Literature searches of PubMed, PEDro and CINAHL databases revealed twenty-one studies included in the final descriptive review, thirteen of which were included in the meta-analysis. Data extraction included baseline and post-intervention means and standard deviations of all eligible outcome measures both for the intervention and control groups, participants baseline demographics and intervention characteristics.

Results

The results showed that Hip&Knee and Hip-only exercise programs were comparatively effective, while the Knee-only exercise programs proved to be inferior to the above-mentioned approaches. The Hip&Knee exercise programs showed the greatest pain relief (mean difference = -1.71 (-3.11, -0.30); p = 0.02; I² = 96%) and functional improvement (standardized mean difference = 1.28 (0.45, 2.12); p = 0.003; I² = 84%), although the subgroup analysis did not show any significant difference compared to Hip-only exercise programs (p > 0.05).

Conclusion

Overall, Hip&Knee exercise programs appear to reduce pain and improve function more than other exercise programs and could be used as a primary rehabilitation approach in patients with PFP. However, the difference between the subgroups in most outcome measures suggests that Hip&Knee exercise programs are no more effective than Hip-only exercise programs.

Imaging of Pediatric Lower Limb Sports Injuries

The importance of physical activity during childhood and adolescence has come to light, with an increase in sports-related acute traumatic and overuse injuries as a major disadvantage. A solid understanding of the physiology of the growing skeleton, together with knowledge about age- and sex-related differences in the occurrence of acute traumatic and overuse injuries is necessary. Every musculoskeletal radiologist should also be familiar with the appearances of these injuries on different imaging modalities. This review focuses on all these aspects concerning acute traumatic and overuse injuries among children and adolescents.

Knee flexor strength, rate of torque development and flexibility in women and men with patellofemoral pain: Relationship with pain and the performance in the single leg bridge test

OBJECTIVES

To investigate the relationship between: (1) knee flexor strength, rate of torque development (RTD), and flexibility with pain level; (2) knee flexor strength and RTD with the performance in the single leg bridge test (SLBT) in women and men with patellofemoral pain (PFP).

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

39 women and 36 men with PFP.

MAIN OUTCOME MEASURES

Knee flexor strength, RTD, and flexibility; performance in the SLBT, current, and worst pain level.

RESULTS

Moderate to strong significant negative relationships were identified between the current pain level with knee flexor strength (r = -0.57 to -0.34) and flexibility (r = -0.44 to -0.35); and between knee flexor strength and RTD with the performance in the SLBT (r = 0.34 to 0.57) in women and men with PFP. Knee flexor RTD was not related to any pain level and no significant relationships were identified between the worst pain level with knee flexor strength and flexibility in women and men with PFP.

CONCLUSIONS

Our results support the potential value of assessing knee flexor strength and flexibility in women and men with PFP. The SLBT may be a useful tool to assess knee flexor muscle capacity in individuals with PFP in a clinical setting.

Task-specific movement training improves kinematics and pain during the Y-balance test and hip muscle strength in females with patellofemoral pain

OBJECTIVES

Task-specific movement training is a proposed intervention for patellofemoral pain aimed to optimise movement during daily tasks. Focused, progressive task practice emphasising optimal limb alignment may yield improvements in performance-based function and hip muscle strength, and transfer learnt movement patterns to untrained tasks. The purpose of this study was to determine if task-specific movement training improves performance-based function (composite score, movement, pain during movement) in an untrained task. Our secondary purpose was to test whether hip muscle strength improved following the movement training intervention.

METHODS

This study was a secondary analysis of a prospective, non-randomised, within-group, double-baseline study. Twenty-three females with patellofemoral pain underwent task-specific movement training two times/week for 6 weeks. Outcomes were collected at three time points: enrolment (baseline), 6 weeks (preintervention) and 12 weeks (postintervention). A repeated measures analysis of variance tested whether the change during the intervention phase was greater than the change during the control phase. Y-balance composite score, hip and knee kinematics and pain during the Y-balance test were primary outcome measures; strength of the hip lateral rotator, abductor and extensor muscles was a secondary outcome measure.

RESULTS

The change in composite score for the Y-balance test was not statistically significantly different between the intervention and control phases (p=0.16). The change during the intervention phase exceeded the change during the control phase for hip and knee kinematics and pain during the Y-balance test, with all variables improving (p<0.0001). The change during the intervention phase was greater than the control phase for hip muscle strength, with all variables improving (p<0.04).

CONCLUSION

Although the Y-balance test composite score did not improve, performance-based function during an untrained task, measured by movement and pain during the test, improved following task-specific movement training. Hip muscle strength improved, despite no focused muscle strengthening.

LEVEL OF EVIDENCE

Level II.

Gait retraining for runners with patellofemoral pain: A protocol for systematic review and meta-analysis

INTRODUCTION

Patellofemoral pain (PFP) is highly prevalent in runners. Physical therapies were proved to be effective in the treatment of PFP. Gait retraining is an important method of physical therapy, but its effectiveness and safety for PFP remained controversial. Previous review suggests gait retraining in the treatment of PFP warrants consideration. However, recent publications of randomized controlled studies and case series studies indicated the positive effect of gait retraining in clinical and functional outcomes, which re-raise the focus of gait retraining. This paper will systematically review the available evidence, assessing the safety and effectiveness for the use of gait retraining for runners with PEP.

METHOD AND ANALYSIS

A systematic review of relevant studies in Pubmed, Embase, SCOPUS, and Cochrane Library were synthesized. Inclusion criteria are studies evaluating clinical outcomes (i.e., changes to pain and/or function) following running retraining interventions in symptomatic running populations; Studies with less than 10 participants in total or in the running retraining intervention group were excluded. The primary outcomes measured will be pain score, Lower extremity functional scale and training related injuries or complications. Review Manager (Revman Version 5.3) software will be used for data synthesis, sensitivity analysis, meta regression, subgroup analysis and risk of bias assessment. A funnel plot will be developed to evaluate reporting bias and Begg and Egger tests will be used to assess funnel plot symmetries. We will use the Grading of Recommendations Assessment, Development and Evaluation system to assess the quality of evidence.

ETHICS AND DISSEMINATION

Our aim is to publish this systematic review in a peer-reviewed journal. Our findings will provide information about the safety of gait retraining and their effect on reliving pain and improving function of lower limb on runners with PEP. This review will not require ethical approval as there are no issues about participant privacy.

Effects of gait retraining with focus on impact versus gait retraining with focus on cadence on pain, function and lower limb kinematics in runners with patellofemoral pain: Protocol of a randomized, blinded, parallel group trial with 6-month follow-up

Patellofemoral pain (PFP) is one of the most prevalent injuries in runners. Unfortunately, a substantial part of injured athletes do not recover fully from PFP in the long-term. Although previous studies have shown positive effects of gait retraining in this condition, retraining protocols often lack clinical applicability because they are time-consuming, costly for patients and require a treadmill. The primary objective of this study will be to compare the effects of two different two-week partially supervised gait retraining programs, with a control intervention; on pain, function and lower limb kinematics of runners with PFP. It will be a single-blind randomized clinical trial with six-month follow-up. The study will be composed of three groups: a group focusing on impact (group A), a group focusing on cadence (group B), and a control group that will not perform any intervention (group C). The primary outcome measure will be pain assessed using the Visual Analog Pain scale during running. Secondary outcomes will include pain during daily activities (usual), symptoms assessed using the Patellofemoral Disorders Scale and lower limb running kinematics in the frontal (contralateral pelvic drop; hip adduction) and sagittal planes (foot inclination; tibia inclination; ankle dorsiflexion; knee flexion) assessed using the MyoResearch 3.14-MyoVideo (Noraxon U.S.A. Inc.). The study outcomes will be evaluated before (t0), immediately after (t2), and six months (t24) after starting the protocol. Our hypothesis is that both partially supervised gait retraining programs will be more effective in reducing pain, improving symptoms, and modifying lower limb kinematics during running compared with the control group, and that the positive effects from these programs will persist for six months. Also, we believe that one gait retraining group will not be superior to the other. Results from this study will help improve care in runners with PFP, while maximizing clinical applicability as well as time and cost-effectiveness.

The effect of speed on Achilles tendon forces and patellofemoral joint stresses in high-performing endurance runners

Achilles tendinopathy and patellofemoral pain are common running injuries associated with increased Achilles tendon (AT) forces and patellofemoral joint (PFJ) stresses. This study examined AT forces and PFJ stresses at different running speeds in high-performing endurance runners. Twenty runners ran overground at four running speeds (3.3, 3.9, 4.8, and 5.6 m/s). AT forces and PFJ stresses were estimated from kinematic and kinetic data. Repeated measures ANOVA with partial eta squared effect sizes was conducted to assess differences between running speeds. Increased peak AT forces (19.5%; p < 0.001) and loading rates (57.3%; p < 0.001) from 3.3 m/s to 5.6 m/s were observed. Cumulative AT loading was greater in the faster speeds compared to the slower speeds. Faster running speeds resulted in increased peak plantar flexor moments, increased peak plantar flexion angles, and a more flexed knee and an anterior center of pressure position at touchdown. Peak PFJ stress was lower in the slowest speed (3.3 m/s) compared to the faster running speeds (3.9-5.6 m/s; p = 0.005). PFJ stress loading rate significantly increased (43.6%; p < 0.001). Greater AT loading observed could be associated with strategies such as increased plantar flexor moments and altered lower body position at touchdown which are commonly employed to generate greater ground contact forces. Greater AT and PFJ loading rates were likely due to shorter ground contact times and therefore less time available to reach the peak. Running at faster speeds could increase the risk of developing Achilles tendinopathy and patellofemoral pain or limit recovery from these injuries without sufficient recovery.

Relationship between Knee Symptoms and Biological Features in Recreational Runners

Objective  The main objective of the present study was to compare the subjective perception of pain and symptoms of anterior knee pain with the different body mass index (BMI) classifications. The secondary objective was to verify the association between biological and anthropometric variables with the results of subjective questionnaires.

Methods  A total of 126 recreational runners from both genders, aged between 20 and 59 years old, were recruited. Data regarding the biological variable (age), anthropometric variables (weight, height), visual analog scale (VAS), and Lysholm and Kujala questionnaires scores were collected. Information was obtained with a digital platform, available through a single link, allowing volunteers to answer these questions using electronic devices. Normality was verified by the Shapiro-Wilk test. T-tests and Wilcoxon tests were used to compare mean values. The association between variables was determined by the Pearson linear correlation.

Results  There were significant differences in height between overweight and grade 1 obesity subjects ( p  = 0.029), in weight and BMI comparing normal weight subjects and both overweight and grade 1 obesity subjects ( p  < 0.001 and p  < 0.05, respectively). An unclear significant correlation was observed between BMI values and specific questionnaires and subjective scale scores ( p  < 0.05).

Conclusion  Recreational runners who present high BMI values are more likely to experience knee pain than those with normal BMI values.

Efficacy of Electromyographic-Biofeedback Supplementation Training with Patellar Taping on Quadriceps Strengthening in Patellofemoral Pain Syndrome among Young Adult Male Athletes

This study compares the effects of electromyographic-biofeedback (EMG-BF)-guided isometric quadriceps strengthening with patellar taping and isometric exercise alone in patellofemoral pain syndrome (PFPS) among young adult male athletes. Sixty young adult male athletes with PFPS participated in the study. Participants were randomly divided into two groups: (1) EMG-BF-guided isometric exercise training with patellar taping (experimental group, n = 30), and (2) sham EMG-BF training with an isometric exercise program (control group, n = 30). Participants conducted their respective exercise programs for five days per week across four weeks. Study outcomes were pain (measured by the visual analog scale), functional disability (measured by the Kujala Anterior Knee Pain scale), and quadriceps strength (measured by an ISOMOVE dynamometer). Measurements were taken at baseline, Week 2, Week 4, and during a follow-up at Week 6. The experimental group demonstrated significantly lower VAS score at Weeks 2 and 4 compared to that of the control group (p = 0.008 and 0.0005, respectively). The score remained significantly lower at the Week 6 follow-up compared to the control group (p = 0.0005). There were no differences in knee function at Weeks 2 and 4 between the two groups (p = 0.086 and 0.171, respectively); however, the experimental group showed significantly better knee function at Week 6 compared to the control group (p = 0.002). There were no differences in quadriceps strength at Week 2 between the two groups (p = 0.259); however, the experimental group demonstrated significantly higher quadriceps strength at Weeks 4 and 6 compared to the control group (p = 0.0008). Four weeks of EMG-BF supplementation training with patellar taping demonstrated significant improvements in pain intensity, functional disability, and quadriceps muscle strength in young adult male athletes with PFPS.

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.

Narrative: Review of Anterior Knee Pain Differential Diagnosis (Other than Patellofemoral Pain)

PURPOSE OF REVIEW

This review presents a framework for constructing a differential diagnosis for chronic anterior knee pain associated with overuse other than patellofemoral pain. Traumatic, systemic, and pediatric injuries will not be covered.

RECENT FINDINGS

From superficial to deep, the anterior knee can be conceptually organized into four layers: (1) soft tissue, (2) extensor mechanism, (3) intracapsular/extrasynovial, and (4) intra-articular. From superficial to deep, diagnoses to consider include bursitis, patellar and quadriceps tendinosis, fat pad impingement, and plica syndromes.

Anteromedial versus posterolateral hip musculature strengthening with dose-controlled in women with patellofemoral pain: A randomized controlled trial

OBJECTIVE

To compare the effectiveness of adding anteromedial versus posterolateral hip musculature strengthening to knee strengthening in women with patellofemoral pain (PFP).

DESIGN

Randomized controlled trial.

SETTING

University physiotherapy clinic.

PARTICIPANTS

Fifty-two women with PFP were randomized to receive either anteromedial (AMHG) or posterolateral (PLHG) hip musculature strengthening.

MAIN OUTCOME MEASURES

The primary outcomes were pain intensity by the numeric pain rating scale and function by the Anterior Knee Pain Scale in six weeks. Secondary outcomes were pain and function at six months, global perceived effect at six weeks and six months, pain in step down, isometric torque of abductors, adductors and hip rotators measured with hand-held dynamometer, and dynamic knee valgus by step down in six weeks.

RESULTS

Both groups showed improvement in primary outcomes; however, no differences were found between groups in pain intensity and function in six weeks and the secondary outcomes. Group x time interaction found superior gains in abductor strength in the PLHG and increase in the strength of the adductors and internal rotators in AMHG.

CONCLUSION

There was no difference between the addition of anteromedial or posterolateral hip musculature strengthening to knee strengthening in improving pain and function in women with PFP.

Adherence to Stepped Care for Management of Musculoskeletal Knee Pain Leads to Lower Health Care Utilization, Costs, and Recurrence

OBJECTIVES

This study aimed to report compliance with stepped care management of patellofemoral pain and determine whether adherence to stepped care results in decreased recurrence and lower health care utilization.

METHODS

A total of 60,730 participants were included, using data from the Military Health System Data Repository, a large single-payer government health system. Outcomes included total knee-related care visits and costs, knee surgeries, opioid prescriptions, and 2-year recurrence. Stepped care was based on interventions delivered within the appropriate timing and in the appropriate order (low risk/cost before high risk/cost).

RESULTS

A total of 54,460 (89.7%) participants received adherent Step 1 care, 10,964 (18.1%) received step 2, and 4168 (6.9%) received step 3. A total of 32.0% and 50.8%, respectively, of all patients in Step 2 and Step 3 care were adherent. Of the 2385 participants (3.9% of cohort) that received both Step 2 and Step 3 care, 24.8% of participants received adherent care. For participants receiving both Step 2 and Step 3 care, adherence resulted in cost savings (mean difference [MD] $1708; 95% confidence interval [CI]: $1241, 2175), fewer knee-related visits (MD 3.4; 95% CI 2.2, 4.7), fewer episodes of knee pain (MD 0.7; 95% CI 0.5, 0.8), fewer knee surgeries (adjusted odds ratio 0.4; 95% CI 0.3, 0.5), and fewer opioid prescriptions (adjusted odds ratio 0.6; 95% CI 0.5, 0.8).

CONCLUSION

These findings demonstrate the value of following stepped care guidelines for pain management in patients with patellofemoral pain.

Static and Dynamic Quadriceps Stretching Exercises in Patients With Patellofemoral Pain: A Randomized Controlled Trial

BACKGROUND

Limited data are available on the effect of stretching exercise in patients with patellofemoral pain (PFP) who have inflexible quadriceps, which is one of the various causes of PFP syndrome. This study compares quadriceps flexibility, strength, muscle activation time, and patient-reported outcomes after static and dynamic quadriceps stretching exercises in patients with PFP who had inflexible quadriceps.

HYPOTHESIS

Quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes would improve with dynamic quadriceps stretching as compared with static quadriceps stretching exercises.

STUDY DESIGN

Randomized controlled trial.

LEVEL OF EVIDENCE

Level 2.

METHODS

Of the 44 patients included in the study, 20 performed static stretching and 24 performed dynamic stretching. Quadriceps flexibility was assessed by measuring the knee flexion angle during knee flexion in the prone position (the Ely test). Muscle strength and muscle activation time were measured using an isokinetic device. The patient-reported outcomes were evaluated using the visual analogue scale for pain and anterior knee pain scale.

RESULTS

No significant differences in quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes in the involved knees were found between the 2 groups (P values > 0.05).

CONCLUSION

Quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes in patients with PFP who had inflexible quadriceps showed no significant differences between the static and dynamic quadriceps stretching exercise groups.

CLINICAL RELEVANCE

Both static and dynamic stretching exercises may be effective for improving pain and function in patients with PFP who have inflexible quadriceps.

Joint position sense in individuals with anterior knee pain

BACKGROUND

Anterior knee pain (AKP) commonly affects both physically active and sedentary individuals and the aetiology is unknown. Altered joint position sense (JPS) impacts accurate motor action and knee joint stability. It is unclear whether people with AKP have altered JPS.

OBJECTIVE

The aim of our study was to investigate JPS in the knees of individuals with AKP.

METHOD

A descriptive cross-sectional study measured JPS in 25 participants with unilateral or bilateral AKP. JPS was measured using active JPS testing during single leg squat (SLS) and active knee extension (AKE) in sitting. Target angles (TA) were self-determined based on each participant's capabilities. The absolute error (AE) was the main outcome measure. Impaired JPS was classified as an AE equal to or greater than five degrees.

RESULTS

There were no significant differences in JPS when comparing the affected and unaffected knees in participants with AKP (p > 0.05). However, a subgroup of participants with altered knee JPS was identified. There was a tendency towards greater knee flexion in the TAs of knees without AKP.

CONCLUSION

Our results showed that JPS is not significantly more impaired in knees with AKP compared with knees without AKP in a group of individuals with AKP. A subgroup with altered JPS in knees with and without AKP was identified. This finding could be because of compensatory gait patterns and the precision of the Vicon 3D motion analysis system.

CLINICAL IMPLICATIONS

Joint position sense should be assessed bilaterally in individuals with AKP.

Influence of symptom frequency and severity on hip abductor strength and endurance in individuals with patellofemoral pain

OBJECTIVE

To compare clinical measures of hip abductor strength and endurance of individuals with patellofemoral pain with more severe symptoms to those with less severe symptoms.

DESIGN

Cross-sectional.

SETTINGS

Laboratory.

PARTICIPANTS

Sixty participants with patellofemoral pain were divided three times into 2 groups according to three symptomatology criteria: functional capacity, pain frequency and pain severity.

MAIN OUTCOME MEASURES

Isometric strength evaluated using a hand-held dynamometer, endurance using maximum number of repetitions and maximum holding time, functional capacity using the Anterior Knee Pain Scale, pain frequency using a 2-category scale ("Less frequent" = 1-2 times a week; "More frequent" = >3 times a week) and pain severity using Numeric Pain Rating Scales.

RESULTS

Participants with more frequent symptoms and with more severe pain were significantly weaker (10%, p = 0.04 and 16%, p = 0.001, respectively), and had less isometric (17%, p = 0.02 and 24%, p = 0.002, respectively) and dynamic (13%, p = 0.02 and 23%, p = 0.007, respectively) endurance compared to those with less pronounced symptoms.

CONCLUSION

Our study highlighted that hip abductor strength and endurance deficits are more pronounced in individuals with more severe and frequent pain.

Non-operative Management of Anterior Knee Pain: Patient Education

PURPOSE OF REVIEW

Anterior knee pain is a multifactorial, often chronic condition, which can lead to long-term pain and disability. The purpose of this review is to examine the latest research on patient education for anterior knee pain. We will focus on how we might use patient education to increase the adoption of other efficacious treatment modalities and offer some suggestions for content and form of effective patient education.

RECENT FINDINGS

New research suggests that patient education, alone, or in combination with targeted exercise therapy, can be effective in reducing pain and improving function in patients with patellofemoral pain. Addressing non-physical or psychological factors may also be an important component of patient education in many patients with chronic pain. Incorporation of new technologies into patient education, such as those available online, or through phone- or tablet-based apps, is likely to be helpful in the future, as we move more towards connecting with patients virtually. Patient education has been shown to be effective in decreasing pain and improving activity in patients with patellofemoral pain. Patient education should be individualized to the patient, focus on the latest effective treatments, and emphasize those treatments that can be self-managed by the patient. Emphasis should also be placed on patient understanding of risk factors and patterns of movement that may lead to, or exacerbate, anterior knee pain. Future research should continue to further characterize the elements of patient education that offer the most efficient treatment benefit.

Are hip and knee kinematics and training load characteristics relate to pain intensity and physical function level in runners with Patellofemoral Pain?

BACKGROUND

Patellofemoral pain (PFP) is the most common running-related injury. Altered hip and knee kinematics and increases in weekly distance and running pace are often associated with PFP development and exacerbation.

RESEARCH QUESTION

Are altered movements and training load characteristics (weekly distance and running pace) relate to pain intensity or physical function level in runners with PFP?

METHODS

Forty recreational runners with PFP (20 males and 20 females) participated in this cross-sectional observational study. Three-dimensional hip and knee kinematics were quantified during the stance phase of running. Weekly distance was defined as the average weekly kilometers of running and running pace as the average pace of the activity measured as minutes per kilometer. A visual analogue scale was used to evaluate worst knee pain during the last week. The anterior knee pain scale (AKPS) was used to evaluate knee functional score. A Pearson correlation matrix was used to investigate the association between each dependent variable (worst pain in the last week and AKPS score) and the independent variables (knee and hip kinematics, weekly distance and running pace).

RESULTS

There was no significantly correlation between kinematic variables, pain and functional score for both males and females separately and combined. Weekly distance (km/week) was found to positively correlate to pain intensity (r = 0.452; p < 0.05) in females with PFP. A simple linear regression revealed that weekly distance was significant predictor emerged of pain in females with PFP. Females exhibited significantly greater peak hip adduction and hip adduction ROM than the males and males had significantly greater running pace compared to females.

SIGNIFICANCE

Weekly distance should be considered in the clinical context during rehabilitation of PFP in females runners aiming at pain reduction.

A Word of Caution for Future Studies in Patellofemoral Pain: A Systematic Review With Meta-analysis

BACKGROUND

Patellar maltracking is widely accepted as an underlying mechanism of patellofemoral pain. However, methodological differences in the literature hinder our ability to generate a universal quantitative definition of pathological patellofemoral kinematics (patellar maltracking) in patellofemoral pain, leaving us unable to determine the cause of patellofemoral pain.

PURPOSE

To systematically review the literature to provide evidence regarding the influence of confounding variables on patellofemoral kinematics.

STUDY DESIGN

Systematic review and random effects meta-analysis of control-case studies.

METHODS

A literature search of case-control studies that evaluated patellofemoral kinematics at or near full extension and were written in English was conducted using Embase, PubMed, Scopus, and Web of Science up to September 2019. Cases were defined as patients with patellofemoral pain. Studies were eliminated if they lacked quantitative findings; had a primary aim to assess therapy efficacy; or included participants with osteoarthritis and/or previous trauma, pathology, or surgery. A quality assessment checklist was employed to evaluate each study. Meta-analyses were conducted to determine the influence of confounding variables on measures of patellofemoral kinematics.

RESULTS

Forty studies met the selection criteria, with quality scores ranging from 13% to 81%. Patient characteristics, data acquisition, and measurement methods were the primary sources of methodological variability. Active quadriceps significantly increased lateral shift (standardized mean difference [SMD]_shift = 0.33; P = .0102) and lateral tilt (SMD_tilt = 0.43; P = .006) maltracking. Individuals with pain secondary to dislocation had greater effect sizes for lateral maltracking than had those with isolated patellofemoral pain (ΔSMD_shift = 0.71, P = .0071; ΔSMD_tilt = 1.38, P = .0055).

CONCLUSION

This review exposed large methodological variability across the literature, which not only hinders the generalization of results, but ultimately mitigates our understanding of the underlying mechanism of patellofemoral pain. Although our meta-analyses support the diagnostic value of maltracking in patellofemoral pain, the numerous distinct methods for measuring maltracking and the limited control for cofounding variables across the literature prohibit defining a single quantitative profile. Compliance with specific standards for anatomic and outcome measures must be addressed by the scientific and clinical community to establish methodological uniformity in this field.

[Expert consensus on surgical treatment of patellofemoral osteoarthritis]

Patellofemoral osteoarthritis (PFOA) is one of the most common causes of anterior knee pain in middle-aged and elderly population. In general, elementary therapy and drug therapy are the preferred choices for PFOA management. However, for those who cannot achieve satisfactory effectiveness with standard non-surgical treatment, surgical therapy stands as an alternative treatment. The surgical therapy includes repair surgery and reconstruction surgery. The choice of surgical plans for PFOA management mainly depends on the etiology, pathogenesis, location, and severity of the lesions. To aid clinical decision-making, the National Clinical Research Center for Geriatric Disorders (Xiangya Hospital) and the Joint Surgery Branch of the Chinese Orthopedic Association arranged nationwide orthopedic specialists to set up a work panel. After reviewing the research progress of surgical therapy and the latest guidelines and consensus for PFOA management, the work panel discussed repeatedly to reach this consensus. The present consensus aims to provide valid evidences for clinical practices of the surgical therapy of PFOA, so as to avoid inappropriate and irregular treatment behaviors, reduce surgical trauma, improve surgical efficacy and the quality of life, and to ease the burden of PFOA.

Proximal, Local, and Distal Muscle Morphology in Women With Patellofemoral Pain

Objective:

The objective of this study was to compare proximal, local, and distal muscle morphology in women with and without patellofemoral pain (PFP).

Materials and Methods:

Proximal, local, and distal muscle thicknesses (MTs) were obtained with B-mode sonography in healthy (control group [CG], n = 20) and PFP (PFP group, n = 20) women. In addition, muscle mass was measured by the sum of the synergistic MTs. Data were analyzed by independent t-test, Mann-Whitney U test, and effect size.

Results:

PFP women had smaller gluteus medius ( P = .02, d = 0.7), vastus medialis ( P < .01, d = 1.0), and flexor digitorum brevis ( P < .01, d = 1.0) MT and greater gastrocnemius medialis ( P = .04, d = 0.6) MT than CG. Quadriceps muscle mass ( P = .01, d = 0.8) and foot muscle mass ( P = .008, d = 0.9) were smaller, while plantar flexor muscle mass was greater in the PFP group than in CG ( P = .01, d = 0.8).

Conclusion:

PFP women have proximal, local, and distal MT alterations in comparison with CG, which may explain possible changes in muscle strength and functionality.

Quantitative volume and dynamic contrast-enhanced MRI derived perfusion of the infrapatellar fat pad in patellofemoral pain

Background

Patellofemoral pain (PFP) is a common knee condition and possible precursor of knee osteoarthritis (OA). Inflammation, leading to an increased perfusion, or increased volume of the infrapatellar fat pad (IPFP) may induce knee pain. The aim of the study was to compare quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters, as imaging biomarkers of inflammation, and volume of the IPFP between patients with PFP and controls and between patients with and without IPFP edema or joint effusion.

Methods

Patients with PFP and healthy controls were included and underwent non-fat suppressed 3D fast-spoiled gradient-echo (FSPGR) and DCE-MRI. Image registration was applied to correct for motion. The IPFP was delineated on FSPGR using Horos software. Volume was calculated and quantitative perfusion parameters were extracted by fitting extended Tofts' pharmacokinetic model. Differences in volume and DCE-MRI parameters between patients and controls were tested by linear regression analyses. IPFP edema and effusion were analyzed identically.

Results

Forty-three controls and 35 PFP patients were included. Mean IPFP volume was 26.04 (4.18) mL in control subjects and 27.52 (5.37) mL in patients. Median K_trans was 0.017 (0.016) min^-1 in control subjects and 0.016 (0.020) min^-1 in patients. None of the differences in volume and perfusion parameters were statistically significant. Knees with effusion showed a higher perfusion of the IPFP compared to knees without effusion in patients only.

Conclusions

The IPFP has been implicated as source of knee pain, but higher DCE-MR blood perfusion, an imaging biomarker of inflammation, and larger volume are not associated with PFP. Patient's knees with effusion showed a higher perfusion, pointing towards inflammation.

Knee flexor strength and rate of torque development deficits in women with patellofemoral pain are related to poor objective function

BACKGROUND

Deficits in knee flexor strength and rate of torque development (RTD) might be present in women with patellofemoral pain (PFP). In addition, maximal strength and RTD of the knee flexors and extensors might be related with subjective and objective function in women with PFP. However, both conjectures are still poorly understood.

RESEARCH QUESTION

Do women with PFP have deficits in the maximal strength and RTD of the knee flexors and extensors during isometric, concentric, and eccentric contractions? Is there a relationship between maximal strength and RTD of the knee flexors and extensors with subjective and objective function in women with PFP?

METHODS

Fifty-six women with, and 46 women without, PFP participated. Maximal strength and RTD (to 30% and 60% maximal torque) during isometric, concentric, and eccentric contractions of the knee flexors and extensors were assessed using an isokinetic dynamometer. Objective assessment included single leg hop test (SLHT) and forward step-down test (FSDT). Subjective assessment involved the anterior knee pain scale.

RESULTS

Women with PFP had small to large deficits in maximal strength and RTD of the knee flexors and extensors during isometric, concentric and eccentric contractions (Effect sizes: -0.43 to -1.10; p ≤ 0.016). Small to moderate correlations of maximal concentric and eccentric knee flexor strength and RTD with SLHT and FSDT (r = 0.28 to 0.41; p ≤ 0.037) were identified. Subjective or objective function were not correlated with maximal isometric knee flexor strength and RTD, or any knee extensor measures (p > 0.05).

SIGNIFICANCE

Maximal strength and RTD deficits of the knee flexors and extensors were identified in this female PFP cohort, but they were unrelated to subjective function. The relationship of concentric and eccentric knee flexor strength and RTD deficits with poor objective function should be considered in future exercise trials for women with PFP.

Patellofemoral alignment, morphology and structural features are not related to sitting pain in individuals with patellofemoral pain

BACKGROUND

Sitting-related pain is a common feature of patellofemoral pain (PFP). However, little is known regarding features associated with sitting-related PFP. The aim of this study was to determine whether sitting-related PFP is associated with patellofemoral alignment, morphology and structural magnetic resonance imaging (MRI) features of the patellofemoral joint (cartilage lesions, bone marrow lesions, fat pad synovitis).

METHODS

133 individuals with PFP were included from two unique but similar cohorts. Participants were classified into one of three groups based on their response to item 8 of the Anterior Knee Pain Scale: (i) problems with sitting; (ii) sitting pain after exercise; and (iii) no difficulty with sitting. All participants underwent 3T Magnetic Resonance Imaging (MRI) to enable: (i) scoring of structural features of the patellofemoral joint with MRI Osteoarthritis Knee Score (MOAKS); and (ii) patellofemoral alignment and morphology measurements using standardised methods. The association of sitting pain to bony alignment, morphology and MOAKS features were evaluated using multinomial logistic regression (adjusted for age, sex, BMI; reference group = no difficulty with sitting).

RESULTS

82 (61.7%) participants reported problems with sitting, and 24 (18%) participants reported sitting pain after exercise. There were no significant associations between the presence of sitting pain and any morphology, alignment or structural characteristics.

CONCLUSIONS

Findings indicate that PFP related to sitting is not associated with patellofemoral alignment, morphology, or structural MRI features of the patellofemoral joint. Further research to determine mechanisms of sitting-related PFP, and inform targeted treatments, are required.

Influence of the exacerbation of patellofemoral pain on trunk kinematics and lower limb mechanics during stair negotiation

BACKGROUND

Although it is assumed that the presence of patellofemoral pain (PFP) may result in compensatory behaviors that can alter trunk kinematics and lower limb mechanics, the influence of the exacerbation of patellofemoral pain on trunk kinematics and lower limb mechanics during stair negotiation has not been established.

RESEARCH QUESTION

Does the exacerbation of PFP symptoms lead to altered trunk kinematics and lower limb mechanics during stair negotiation?

METHODS

Three-dimensional kinematics and kinetics were obtained from 45 women with PFP during stair descent and ascent. Data were obtained before and after a pain exacerbation protocol. The variables of interest were peak trunk, hip, and knee flexion, and ankle dorsiflexion; peak hip, and knee extensor, and ankle plantarflexor moments. Paired t-tests were used to compare the variables of interest before and after pain exacerbation.

RESULTS

Following pain exacerbation, there was a decrease in peak knee extensor moment during stair descent (Effect size = -0.68; p = 0.01) and stair ascent (Effect size = -0.56; p = 0.02); as well as in peak ankle dorsiflexion during stair descent (Effect size = -0.33; p = 0.01) and stair ascent (Effect size = -0.30; p = 0.01). An increase in ankle plantarflexor moment during stair descent (Effect size = 0.79; p < 0.01) and stair ascent (Effect size = 0.89; p < 0.01) was also observed. No significant differences were observed for peak trunk, hip, and knee flexion or hip extensor moment (p > 0.05).

SIGNIFICANCE

Our findings show compensatory strategies used by people with PFP in response to symptoms exacerbation that may have a negative impact on knee and ankle mechanics. Our findings also suggest that people with PFP do not seem to change their trunk, hip, and knee flexion or hip extensor moment during stair negotiation in response to symptom exacerbation.

Women with patellofemoral pain and knee crepitus have reduced knee flexion angle during stair ascent

OBJECTIVES

To compare trunk and knee biomechanics of women with and without patellofemoral pain (PFP) and knee crepitus during stair ascent.

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

29 women with PFP and knee crepitus (PFP_Crepitus); 28 women with PFP and no knee crepitus (PFP_NOCrepitus); 17 pain-free women with knee crepitus (Pain-free_Crepitus); and 29 pain-free women without knee crepitus (Pain-free_NOCrepitus).

MAIN OUTCOME MEASURES

Peak trunk flexion, peak knee flexion, mean knee angular velocity, knee extensor moment at peak knee flexion, peak and impulse of the knee extensor moment.

RESULTS

PFP_Crepitus group performed the stair ascent task with reduced peak knee flexion compared to Pain-free_Crepitus (p = 0.04; Effect size = -0.85) and Pain-free_NOCrepitus (p = 0.03; Effect size = -0.75). No significant differences among groups were found for peak trunk flexion (p = 0.979), knee angular velocity (p = 0.420), knee extensor moment at peak knee flexion (p = 0.933), peak (p = 0.290) and impulse (p = 0.122) of the knee extensor moment.

CONCLUSION

Women with concomitant PFP and knee crepitus demonstrated reduced knee flexion during stair ascent, but no significant differences for trunk flexion and knee extensor moment variables were found.

Short-term effectiveness of an intervention targeting lower limb range of motion on pain and disability in patellofemoral pain patients: A randomized, non-concurrent multiple-baseline study

INTRODUCTION

Patellofemoral pain (PFP) is a common and often long-standing musculoskeletal condition. Evidence of the effectiveness of interventions addressing soft tissue flexibility is conflicting and of inconsistent scientific quality. However, reduced soft tissue flexibility can negatively affect patellofemoral joint kinematics. Lower limb range of motion (LLROM) reflects soft tissue flexibility throughout the kinetic chain. The aim was to evaluate the short-term effectiveness of an intervention targeting LLROM on pain and disability in patients with PFP.

METHODS

A randomized, non-concurrent, multiple-baseline single-case design with a two-week intervention phase and baseline and postintervention phase with varying length was conducted. Eight participants (5 females, 3 males) of age 19(±1.6) years, weekly sports participation 12(±3.1) hours and 17(±14) months symptom duration were included. The Anterior Knee Pain Scale - Dutch Version (AKPS-DV) and the Patient Specific Complaint Scale (PSCS) were administered twice a week. After allocating participants to one of four subgroups of reduced LLROM the intervention was applied. The intervention consisted of soft tissue techniques (mobilization, taping, and stretching).

RESULTS

Participant 3 and 6 showed a medium and small but statistically significant positive effect on the AKPS-DV. Participant 2 showed a large and statistically significant positive effect on the PSCS.

CONCLUSIONS

This study provides moderate evidence that an intervention targeting LLROM in patients with PFP reduces pain and disability in the short-term. Further research is needed to evaluate the long-term effectiveness and optimize individual treatment outcomes.

The effectiveness of superimposed neuromuscular electrical stimulation combined with strengthening exercises on patellofemoral pain: A randomized controlled pilot trial

BACKGROUND

Patellofemoral pain (PFP) is one of the most common disorders of the knee. Neuromuscular electrical stimulation (NMES) is often assumed by clinicians to be an effective adjunctive therapy to quadriceps strengthening.

OBJECTIVE

The aim of this study was to assess the efficacy of superimposed NMES combined with strengthening exercises to improve the recovery of quadriceps strength and function in patients with PFP.

METHODS

This study was planned as a single blind randomized controlled pilot study. A total of twenty-seven patients diagnosed with PFP were randomly assigned into 2 groups. Patients received superimposed NMES in addition to the standardized program (Group I) or only the standardized program (Group II). The patients in both groups were treated 3 times a week for 6 weeks and followed at 12 weeks. Primary outcome measure was quadriceps isokinetic muscle strength. The changes in dependent variables before treatment, 6th, and 12th weeks were analyzed using a 2 × 3 mixed-model analysis of variance.

RESULTS

There were significant improvements in the within groups statistics of all parameters for both groups (p< 0.05). No differences in quadriceps strength, Kujala and Lysholm scores between groups were found at the different time points [F (2, 21) = 0.86; p= 0.12, F (2, 21) = 0.001; p= 0.97, F (2, 21) = 0.12; p= 0.73, respectively].

CONCLUSIONS

The results indicate that superimposed NMES combined with the standardized rehabilitation program has no clinically significant superiority to standardized rehabilitation program alone.

Patellofemoral joint loading during the forward and backward lunge

OBJECTIVE

To examine patellofemoral joint (PFJ) loading in two lunge movements: Forward Lunge (FL) and Backward Lunge (BL).

DESIGN

Repeated Measures.

SETTING

University Biomechanics Laboratory.

PARTICIPANTS

20 asymptomatic females.

MAIN OUTCOME MEASURES

Six trials of two lunge movements (FL and BL) to a depth of 75% of leg length were performed. 3-D motion capture and force platforms were used to collect data as input into a musculoskeletal model to determine quadriceps force, PFJ reaction force, PFJ stress, and knee flexion angle.

RESULTS

Multivariate analysis indicated differences in PFJ loading variables and joint angles between the lunge movements (Forward vs. Backward) and phases (Down vs. Up). Quadriceps force, PFJ reaction force, and knee flexion angle were larger in the FL movement and Up phases. PFJ loading rate was greater in the FL movement along with a lower forward trunk tilt.

CONCLUSION

The FL produced greater PFJ loading variables compared to the BL. Further research is needed to examine a population of individuals who have patellofemoral pain (PFP) to see if their symptoms may be reduced when using the BL.

Effect of gait retraining on segment coordination and joint variability in individuals with patellofemoral pain

BACKGROUND

Gait retraining is advocated for the management of patellofemoral pain. This case series examined changes in lower limb variability following 6-weeks of gait retraining in individuals with patellofemoral pain.

METHODS

Six runners with patellofemoral pain completed a 6-week physiotherapist-guided gait retraining program using minimalist footwear and increased cadence. Approximate entropy joint variability and segment coordination variability were calculated across the entire gait cycle during running at baseline, 6 and 12 weeks and compared using repeated measures analysis of variance and the standardised mean difference (SMD).

FINDINGS

Compared to baseline, there were large increases in hip joint transverse plane kinematic variability at 6 (SMD = 1.7) and 12 weeks (SMD = 1.3). Moderate increases in hip joint frontal plane and knee joint sagittal plane kinematic variability were also observed at 6 (SMD = 1.1 & 0.96) and 12 weeks (SMD = 1.1 & 0.89). Knee joint frontal plane and hip joint transverse plane kinetic variability demonstrated large increases from baseline at 6 (SMD = 1.3 & 0.9) and 12 weeks (SMD = 0.9 & 1.0). There was no main effect of time for segment coordination variability. All participants had clinically meaningful improvements in pain (visual analogue change score > 20 mm).

INTERPRETATION

Gait retraining increased joint kinematic and kinetic variability in those with patellofemoral pain and these changes persisted over 12 weeks. Increased variability was observed in joint kinematics and kinetics known to influence patellofemoral joint stress, which may vary patellofemoral joint loading patterns and partly explain the clinical effect.

Physical Therapist Management of Anterior Knee Pain

PURPOSE OF REVIEW

Anterior knee pain is a common musculoskeletal complaint among people of all ages and activity levels. Non-operative approaches with an emphasis on physical therapy management are the recommended initial course of care. The purpose of this review is to describe the current evidence for physical therapist management of anterior knee pain with consideration of biomechanical and psychosocial factors.

RECENT FINDINGS

The latest research suggests anterior knee pain is a combination of biomechanical, neuromuscular, behavioral, and psychological factors. Education strategies to improve the patient's understanding of the condition and manage pain are supported by research. Strong evidence continues to support the primary role of exercise therapy and load progression to achieve long-term improvements in pain and function. Preliminary studies suggest blood flow restriction therapy and movement retraining may be useful adjunct techniques but require further well-designed studies. Anterior knee pain includes multiple conditions with patellofemoral pain being the most common. An insidious onset is typical and often attributed to changes in activity and underlying neuromuscular impairments. A thorough clinical history and physical examination aim to identify the patient's pain beliefs and behaviors, movement faults, and muscle performance that will guide treatment recommendations. Successful physical therapist management involves a combination of individualized patient education, pain management, and load control and progression, with an emphasis on exercise therapy.

Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial

OBJECTIVE

To compare the effectiveness of progressive tendon-loading exercises (PTLE) with eccentric exercise therapy (EET) in patients with patellar tendinopathy (PT).

METHODS

In a stratified, investigator-blinded, block-randomised trial, 76 patients with clinically diagnosed and ultrasound-confirmed PT were randomly assigned in a 1:1 ratio to receive either PTLE or EET. The primary end point was clinical outcome after 24 weeks following an intention-to-treat analysis, as assessed with the validated Victorian Institute of Sports Assessment for patellar tendons (VISA-P) questionnaire measuring pain, function and ability to play sports. Secondary outcomes included the return to sports rate, subjective patient satisfaction and exercise adherence.

RESULTS

Patients were randomised between January 2017 and July 2019. The intention-to-treat population (mean age, 24 years, SD 4); 58 (76%) male) consisted of patients with mostly chronic PT (median symptom duration 2 years). Most patients (82%) underwent prior treatment for PT but failed to recover fully. 38 patients were randomised to the PTLE group and 38 patients to the EET group. The improvement in VISA-P score was significantly better for PTLE than for EET after 24 weeks (28 vs 18 points, adjusted mean between-group difference, 9 (95% CI 1 to 16); p=0.023). There was a trend towards a higher return to sports rate in the PTLE group (43% vs 27%, p=0.13). No significant between-group difference was found for subjective patient satisfaction (81% vs 83%, p=0.54) and exercise adherence between the PTLE group and EET group after 24 weeks (40% vs 49%, p=0.33).

CONCLUSIONS

In patients with PT, PTLE resulted in a significantly better clinical outcome after 24 weeks than EET. PTLE are superior to EET and are therefore recommended as initial conservative treatment for PT.

A Contemporary Approach to Patellofemoral Pain in Runners

Patellofemoral pain (PFP) is among the most common injuries in recreational runners. Current evidence does not identify alignment, muscle weakness, and patellar maltracking or a combination of these as causes of PFP. Rather than solely investigating biomechanics, we suggest a holistic approach to address the causes of PFP. Both external loads, such as changes in training parameters and biomechanics, and internal loads, such as sleep and psychological stress, should be considered. As for the management of runners with PFP, recent research suggested that various interventions can be considered to help symptoms, even if these interventions target biomechanical factors that may not have caused the injury in the first place. In this Current Concepts article, we describe how the latest evidence on education about training modifications, strengthening exercises, gait and footwear modifications, and psychosocial factors can be applied when treating runners with PFP. The importance of maintaining relative homeostasis between load and capacity will be emphasized. Recommendations for temporary or longer-term interventions will be discussed. A holistic, evidence-based approach should consist of a graded exposure to load, including movement, exercise, and running, while considering the capacity of the individual, including sleep and psychosocial factors. Cost, accessibility, and the personal preferences of patients should also be considered.

Psychological and Pain Sensitization Characteristics Are Associated With Patellofemoral Osteoarthritis Symptoms: The Multicenter Osteoarthritis Study

OBJECTIVE

Determine the relation of symptomatic and structural features of patellofemoral osteoarthritis (PFOA) to psychological characteristics and measures of pain sensitization, in older adults with or at risk of knee osteoarthritis (OA).

METHODS

This study included 1112 participants from the Multicenter Osteoarthritis Study (713 females, mean age 66.8 ± SD 7.6 yrs, body mass index 29.5 ± 4.8 kg/m²). Participants were grouped based on the presence of PFOA symptoms (anterior knee pain and pain on stairs) and magnetic resonance imaging (MRI) PFOA (full-thickness cartilage lesion with bone marrow lesion): (1) patellofemoral (PF) symptoms with MRI PFOA; (2) PF symptoms without MRI PFOA; (3) MRI PFOA without PF symptoms; and (4) no PF symptoms or MRI PFOA (no PFOA). Relation of PFOA classification to depressive symptoms, catastrophizing, temporal summation (TS) and pressure pain thresholds (PPT) was evaluated using logistic (categorical variables) and linear regression (continuous variables).

RESULTS

Compared with no PFOA, those with PF symptoms with or without MRI PFOA had significantly greater odds of depressive symptoms, catastrophizing, and patellar TS (OR range 1.5-2.01), and those with PF symptoms without MRI PFOA had significantly greater odds of wrist TS (OR 1.66). Males with PF symptoms without MRI PFOA had significantly lower pressure PPT at the patella compared with no PFOA and those with MRI PFOA only (no symptoms). There were no significant differences at the wrist for males, or the patella or wrist for females.

CONCLUSION

Persons with PFOA symptoms, regardless of MRI PFOA status, are more likely to demonstrate depressive symptoms, catastrophizing, and TS. Males with PFOA symptoms without MRI PFOA demonstrate local hyperalgesia.

Is patellofemoral pain preventable? A systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To evaluate the effectiveness of interventions to reduce the risk of incident patellofemoral pain.

DESIGN

Systematic review and meta-analysis, with strength of evidence evaluated separately for each intervention type.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, Web of Science and SPORTDiscus.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials evaluating the effectiveness of interventions to reduce patellofemoral pain risk compared with a control/non-exposed group.

RESULTS

Thirteen trials of mostly military recruits and young athletes analysed six different interventions. There was low certainty evidence from two trials (227 participants) that patellofemoral braces worn during physical activity (compared with no brace) effectively reduced the risk of patellofemoral pain (risk ratio (RR) 0.40, 95% CI 0.22 to 0.73; I2=24.0%). There was low certainty evidence from one trial (320 participants) that running technique retraining to (run softer) reduced patellofemoral pain risk (RR 0.21, 95% CI 0.07 to 0.60). There was low certainty evidence from four trials (3364 participants) that multicomponent (strengthening/neuromuscular) exercise programmes did not significantly reduce the risk of patellofemoral pain (RR 0.49, 95% CI 0.18 to 1.36; I2=64.9%), although broad CIs may reflect exercise dose variations among studies. There was very low certainty evidence from four trials (2314 participants) that foot orthoses (compared with flat inserts/no orthosis) did not significantly reduce the risk of patellofemoral pain (RR 0.63, 95% CI 0.35 to 1.13; I2=0.0%). Static stretching and a running programme that progressed intensity (compared with volume) did not significantly influence patellofemoral pain risk (single studies).

CONCLUSION

There is low-level evidence that patellofemoral braces and running technique retraining can reduce the risk of patellofemoral pain by 60%-79%.

Medical Interventions for Patellofemoral Pain and Patellofemoral Osteoarthritis: A Systematic Review

Patellofemoral pain (PFP) and patellofemoral osteoarthritis (PFOA) are common, persistent conditions that may lie along a pathological spectrum. While evidence supports exercise-therapy as a core treatment for PFP and PFOA, primary care physicians commonly prescribe medication, or refer for surgical consults in persistent cases. We conducted a systematic review of medical interventions (pharmaceutical, nutraceutical, and surgical) for PFP and PFOA to inform primary care decision making. Methods: Following protocol registration, we searched seven databases for randomized clinical trials of our target interventions for PFP and PFOA. Our primary outcome was pain. We assessed risk of bias, calculated standardized mean differences (SMDs) and determined the level of evidence for each intervention. Results: We included 14 publications investigating pharmaceutical or nutraceutical interventions, and eight publications investigating surgical interventions. Two randomized control trials (RCTs) provided moderate evidence of patellofemoral arthroplasty having similar pain outcomes compared to total knee arthroplasty in isolated PFOA, with SMDs ranging from −0.3 (95% CI −0.8, 0.2, Western Ontario McMaster Pain Subscale, 1 year post-surgery) to 0.3 (−0.1, 0.7, SF-36 Bodily Pain, 2 years post-surgery). Remaining studies provided, at most, limited evidence. No efficacy was demonstrated for oral nonsteroidal anti-inflammatories or arthroscopic surgery. Conclusions: Pharmaceutical and nutraceutical prescriptions, and surgical referrals are currently being made with little supporting evidence, with some interventions showing limited efficacy. This should be considered within the broader context of evidence supporting exercise-therapy as a core treatment for PFP and PFOA.

Associations of foot and ankle characteristics with knee symptoms and function in individuals with patellofemoral osteoarthritis

BACKGROUND

Foot and ankle characteristics are associated with patellofemoral pain (PFP) and may also relate to patellofemoral osteoarthritis (PFOA). A greater understanding of these characteristics and PFOA, could help to identify effective targeted treatments.

OBJECTIVES

To determine whether foot and ankle characteristics are associated with knee symptoms and function in individuals with PFOA.

METHODS

For this cross-sectional study we measured weightbearing ankle dorsiflexion range of motion, foot posture (via the Foot Posture Index [FPI]), and midfoot mobility (via the Foot Measurement Platform), and obtained patient-reported outcomes for knee symptoms and function (100 mm visual analogue scales, Anterior Knee Pain Scale [AKPS], Knee injury and Osteoarthritis Outcome Score, repeated single step-ups and double-leg sit-to-stand to knee pain onset). Pearson's r with significance set at p < 0.05 was used to determine the association between foot and ankle charateristics, with knee symptoms and function, adjusting for age.

RESULTS

188 participants (126 [67%] women, mean [SD] age of 59.9 [7.1] years, BMI 29.3 [5.6] kg/m2) with symptomatic PFOA were included in this study. Lower weightbearing ankle dorsiflexion range of motion had a small significant association with higher average knee pain (partial r = - 0.272, p < 0.001) and maximum knee pain during stair ambulation (partial r = - 0.164, p = 0.028), and lower scores on the AKPS (indicative of greater disability; partial r = 0.151, p = 0.042). Higher FPI scores (indicating a more pronated foot posture) and greater midfoot mobility (foot mobility magnitude) were significantly associated with fewer repeated single step-ups (partial r = - 0.181, p = 0.023 and partial r = - 0.197, p = 0.009, respectively) and double-leg sit-to-stands (partial r = - 0.202, p = 0.022 and partial r = - 0.169, p = 0.045, respectively) to knee pain onset, although the magnitude of these relationships was small. The amount of variance in knee pain and disability explained by the foot and ankle characteristics was small (R2-squared 2 to 8%).

CONCLUSIONS

Lower weightbearing ankle dorsiflexion range of motion, a more pronated foot posture, and greater midfoot mobility demonstrated small associations with worse knee pain and greater disability in individuals with PFOA. Given the small magnitude of these relationships, it is unlikely that interventions aimed solely at addressing foot and ankle mobility will have substantial effects on knee symptoms and function in this population.

TRIAL REGISTRATION

The RCT was prospectively registered on 15 March 2017 with the Australia and New Zealand Clinical Trials Registry ( ANZCTRN12617000385347 ).

Effects of exercise combined with whole body vibration in patients with patellofemoral pain syndrome: a randomised-controlled clinical trial

BACKGROUND

Patellofemoral pain is a prevalent condition in the general population, especially in women, and produces functional impairment in patients. Therapeutic exercise is considered an essential part of the conservative management. The use of vibration platforms may help improve strength and function and reduce pain in patients with knee disorders. The aim of this investigation was to determine the effects of adding whole body vibration (vertical, vibration frequency of 40 Hz, with an amplitude from 2 to 4 mm) to an exercise protocol for pain and disability in adults with patellofemoral pain.

METHODS

A randomised clinical trial was designed, where 50 subjects were randomly distributed into either an exercise group plus whole body vibration or a control group. Pain, knee function (self-reported questionnaire) and range of motion and lower limb functionality were assessed at baseline and at 4 weeks. The experimental group performed 12 supervised sessions of hip, knee and core strengthening exercises on a vibration platform 3 times per week during 4 weeks. The control group followed the same protocol but without vibration stimuli. Differences in outcome measures were explored using an analysis of the variance of 2 repeated measures. Effect sizes were estimated using Square Eta (η2). Significant level was set al P < 0.05.

RESULTS

Statistically significant differences were found after intervention in favour of the experimental group in the between-groups comparison and in the interaction of the experimental group before and after treatment in terms of pain perception (P = 0.000; η2 = 0.63) and function outcomes scores (P = 0.000; η2 0.39 and 0.51 for lower limb functional scale and Kujala scores respectively).

CONCLUSION

A 4-week whole body vibration exercise programme reduces pain level intensity and improves lower limb functionality in patellofemoral pain patients and is more effective than exercise alone in improving pain and function in the short-term.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT04031248 ). This study was prospectively registered on the 24th July, 2019.

Validity and reliability of 2-dimensional trunk, hip, and knee frontal plane kinematics during single-leg squat, drop jump, and single-leg hop in females with patellofemoral pain

OBJECTIVES

To investigate validity and between-session reliability of frontal plane trunk, hip, and knee kinematics during three functional tasks in females with patellofemoral pain (PFP).

DESIGN

Observational.

SETTING

Research Laboratory.

PARTICIPANTS

20 females with PFP (22.7 ± 3.2 years, 69.9 ± 9.2 kg, 167.7 ± 9.6 cm).

MAIN OUTCOME MEASURES

Trunk, hip, and knee frontal plane peak angles during the single leg squat (SLS), drop vertical jump (DVJ), and single leg hop (SLH) kinematics were evaluated using 2-dimensional (2D) and 3-dimensional (3D) motion capture. Participants returned to the lab one week later and competed a second 2D analysis of the functional tasks. Concurrent validity was assessed by evaluating relationship between 2D and 3D frontal plane kinematics with Pearson correlations. Between-session reliability was assessed by evaluating 2D kinematics with intraclass correlation coefficients by a single assessor.

RESULTS

Moderate to strong correlations (r = 0.55-0.76, p < .05) were found for frontal plane hip kinematics during all three tasks and the trunk during the SLH. Frontal plane kinematics demonstrated good to excellent test-retest reliability for each of the three tasks, (ICC _(2,1) = 0.70-0.90).

CONCLUSION

2D hip joint angles during the three functional tasks were the only valid frontal plane angles. Trunk, hip, and knee 2D frontal plane kinematics ranged between good-excellent reliability.

The influence of prior opioid use on healthcare utilization and recurrence rates for non-surgical patients seeking initial care for patellofemoral pain

INTRODUCTION/OBJECTIVES

Prior opioid use can influence outcomes for patients with musculoskeletal disorders. The purpose of this study was to compare downstream medical utilization-based outcomes (costs, visits, recurrent episodes) after an initial diagnosis of patellofemoral pain based on pre-injury utilization of opioids.

METHOD

A total of 85,7880 consecutive patients were followed for a full 12 months before and 24 months after an initial diagnosis of patellofemoral pain (January 2009 to December 2013). Data were sourced from the Military Health System Data Repository, a single-payer closed government system. Opioid prescription fills were identified, and medical visits and costs were calculated for all knee-related medical care, to include recurrence rates in the 2-year surveillance period.

RESULTS

A relatively small number of individuals filled an opioid prescription in the year prior (n = 1746; 2.0%); however, these individuals had almost twice the mean costs of knee-related medical care ($1557 versus %802) and medical visits (8.4 versus 4.0). Patients with prior opioid use were more likely to have at least 1 recurrent episode of knee pain (relative risk 1.58, 95% CI 1.51, 1.65) with a higher mean number of episodes of knee pain (1.5 vs 1.8). The use of opioids with higher risk of misuse or dependency (Schedule II or III) resulted in greater medical costs (for any reason) and recurrent episodes of knee pain compared to the use of opioids in a lower risk category (Schedule IV).

CONCLUSIONS

Prior opioid utilization was associated with a greater number of recurrent episodes of knee pain and higher downstream medical costs compared with individuals without prior opioid use. For individuals with prior opioid utilization, opioids with higher risk of misuse or dependency (Schedule II or III) resulted in greater medical costs (for any reason) and recurrent episodes compared to the use of lower-risk opioids (Schedule IV). Key Points • Patients with prior opioid use had much greater knee-related medical costs compared to patients without prior opioid use. • Patients with prior opioid use were more likely to have additional episodes of knee pain in the following 2 years compared to patients without prior opioid use. • Prior opioid use has predicted higher costs and poor outcomes after surgery, but this is the first study to confirm similar findings in non-surgical patients.

Patellofemoral joint kinetics in females when using different depths and loads during the barbell back squat

Back squats are a common strengthening exercise for knee and hip musculature. However, repetitive loaded movements like backs squats result in high patellofemoral joint loading and therefore may contribute to the development of common overuse injuries. Thus, it is important to understand how changing parameters such as squat depth or load influences patellofemoral loading. This study investigated differences in patellofemoral loading when experienced female lifters squatted to three depths (above parallel, parallel, and below parallel) and with three loads (unloaded, 50%, and 85% of depth-specific one repetition maximums). Patellofemoral joint reaction forces (pfJRF) and stresses (pfJS) were calculated from biomechanical models incorporating knee extensor moments (KEM) and joint angles. Peak KEMs displayed a depth-by-load interaction such that within each depth, as load increased so did peak KEM. However, within each load, the effects of depth were different. Peak pfJRF also increased with load and was higher at below parallel than above or parallel depths. Peak pfJS also displayed a depth-by-load interaction, increasing with load within a given depth, and being greatest at the below parallel depths within a given load. If patellofemoral joint loading is a concern, clinicians or coaches should carefully monitor the depth and load combinations being used.

Effects of Trigger Point Dry Needling on Neuromuscular Performance and Pain of Individuals Affected by Patellofemoral Pain: A Randomized Controlled Trial

Purpose

To investigate the effects of trigger point dry needling (TrP-DN) on exercise-induced patellofemoral pain syndrome (PFPS).

Patients and Methods

In this randomized, single-blind, parallel-group trial, 50 patients with PFPS were randomly allocated to the following two groups: the TrP-DN group (n = 25) and the Sham needling group (n = 25). Patients in both groups were asked to perform a stretching exercise of the quadriceps daily after needling. The needling group received a single session of TrP-DN to trigger points (TrPs) in the vastus medialis oblique (VMO), vastus lateralis (VL), and rectus femoris muscles (once a week for 6 weeks), and the Sham group received placebo needling. Visual analogue scale (VAS) for pain intensity and Kujala questionnaire for the functional status were assessed before treatment, 3 and 6 weeks after treatment, and at the 3-month follow-up. The ratio of the myoelectric amplitude of the vastus medialis oblique and vastus lateralis muscles (VMO/VL) was assessed before treatment and 6 weeks after treatment.

Results

There was no significant difference in the general data between the two groups. The VAS scores and Kujala scores in the TrP-DN group were significantly improved and increased at the 3-week treatment visit, 6-week treatment visit, and 3-month follow-up compared to the scores before treatment; and the scores in the Sham group were only significantly improved at the 3-week treatment visit, and 6-week treatment visit. VAS scores in the TrP-DN group were significantly lower and Kujala scores were significantly higher at the 6-week treatment visit and the 3-month follow-up compared to those in the Sham group. The VMO/VL ratio in the TrP-DN group was significantly increased at the 6-week treatment visit compared to that before treatment.

Conclusion

TrP-DN at the quadriceps combined with stretch can reduce the pain, and improves the clinical symptoms and function, the VMO/VL ratio, and the coordination of VMO and VL in patients with PFPS.

HAPPi Kneecaps! Protocol for a participant- and assessor-blinded, randomised, parallel group feasibility trial of foot orthoses for adolescents with patellofemoral pain

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 co-interventions, 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.

Discussion

Findings of this study will inform the feasibility of a full-scale RCT investigating the efficacy of contoured foot orthoses in adolescents with PFP. This full-scale study is necessary to improve the evidence base for management of adolescent PFP, and enhance outcomes for this population.

Trial registration

ACTRN12619000957190.

Hot and cold knees: exploring differences in patella skin temperature in patients with patellofemoral pain

OBJECTIVES

To investigate the distribution of patella skin temperature (Tsk) measurements and to explore the presence of temperature subgroups in patellofemoral pain (PFP) patients.

DESIGN

Cross-sectional observational study design.

PARTICIPANTS

One dataset of 58 healthy participants and 232 PFP patients from three different datasets.

MAIN OUTCOME MEASURES

Patella skin temperature, measured by physiotherapists using a low cost hand held digital thermometer. The distribution of patella skin temperature was assessed and compared across datasets. To objectively determine the clinically meaningful number of subgroups, we used the average silhouette method. Finite mixture models were then used to examine the presence of PFP temperature subgroups. Receiver operating characteristic curves were used to estimate optimal patella Tsk thresholds for allocation of participants into the identified subgroups.

RESULTS

In contrast to healthy participants, the patella skin temperature had an obvious bimodal distribution with wide dispersion present across all three PFP datasets. The fitted finite mixture model suggested three temperature subgroups (cold, normal and hot) that had been recommended by the average silhouette method with discrimination cut-off thresholds for subgroup membership based on receiver operating curve analysis of Cold=<30.0°C; Normal 30.0-35.2°C; Hot ≥35.2°C.

CONCLUSION

A low cost hand held digital thermometer appears to be a useful clinical tool to identify three PFP temperature subgroups. Further research is recommended to deepen understanding of these clinical findings and to explore the implications to different treatments.