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

How does acute pain influence biomechanics and quadriceps function in individuals with patellofemoral pain?

OBJECTIVES

Beside pathophysiological factors, pain is believed to play a crucial role in the progression of patellofemoral pain (PFP). However, the isolated effect of pain on biomechanics and quadriceps function has not been investigated in PFP. Thus, this study aimed to investigate the effect of pain on quadriceps function and lower limb biomechanics in individuals with PFP.

METHODS

Twenty-one individuals with PFP (11 males and 10 females, age: 29.76 ± 6.36 years, height: 1.74 ± 0.09 m, mass: 70.12 ± 8.56 kg) were measured at two different occasions: when not and when experiencing acute pain. Peak quadriceps torque (concentric, eccentric and isometric) and arthrogenic muscle inhibition (AMI) were assessed. Three-dimensional motion analysis and surface electromyography of the quadriceps and hamstring muscles were collected during running, a single-leg-squat and step-down task. The normality was assessed using the Shapiro-Wilk test and a MANOVA was performed at the 95% confidence interval.

RESULTS

AMI increased significantly in acute pain. The net muscle activation of the knee extensors and flexors decreased during running in acute pain. The lower limb biomechanics and the quadriceps torque did not change in acute pain.

DISCUSSION

It appears that even if individuals with PFP experience pain they can still deliver maximal quadriceps contractions and maintain their moving patterns without biomechanical changes. However, the overall reduced activation of the quadriceps and the increased AMI indicate the presence of quadriceps inhibition in acute pain.

THE EFFECTS OF POSTERIOR TIBIAL MOBILIZATION ON MENISCAL MOVEMENT: AN IN-SITU INVESTIGATION

BACKGROUND

Anterior knee pain during knee extension may be related to a meniscal movement restriction and increased meniscal load during function. One method of treatment involves the use of manual posterior mobilization of the tibia to specifically target the meniscotibial interface of the knee joint.

PURPOSE

The purpose of this study was to measure motion at a cadaveric medial meniscus anterior horn during a posterior tibial mobilization.

STUDY DESIGN

Prospective, multifactorial, repeated-measures laboratory study.

METHODS

Eight unembalmed cadaveric knee specimens were mounted in a custom apparatus and markers were placed in the medial meniscus, tibia and femur. The tibia was posteriorly mobilized in two randomized knee positions (0 degrees and 25 degrees) using three randomly assigned loads (44.48N, 88.96N, and 177.93N). Markers were photographed and digitally measured and analyzed.

RESULTS

All load x position conditions produced anterior displacement of the meniscus on the tibia, where the displacement was significant [t (7) = -3.299; p = 0.013] at 0 degrees loaded with 177.93N (mean 0.41 ± 0.35 mm). The results of 2(position) x 3(load) repeated measures ANOVA for meniscotibial displacement produced no significant main effects for load [F (2,14) = 2.542; p = 0.114) or position [F (1,7) = 0.324, p = 0.587]. All load x position conditions produced significant posterior tibial and meniscal displacement on the femur. The 2(position) x 3(load) repeated measures ANOVA revealed a significant main effect for load for both femoral marker displacement relative to the tibial axis [F (2,14) = 77.994; p < 0.001] and meniscal marker displacement relative to the femoral marker [F (2,14) = 83.620; p < 0.001].

CONCLUSION

Use of a mobilization technique to target the meniscotibial interface appears to move the meniscus anteriorly on the tibia. It appears that this technique may be most effective at the end range position.

LEVEL OF EVIDENCE

2 (laboratory study).

Kinesiophobia, but not strength is associated with altered movement in women with patellofemoral pain

BACKGROUND

Evidence indicates the presence of both kinesiophobia and knee extension strength deficits in women with patellofemoral pain (PFP). Both impairments may contribute to apparent compensatory gait patterns including reduced cadence and peak knee flexion during stair negotiation.

RESEARCH QUESTION

Is kinesiophobia or knee extension strength associated with movement pattern in women with patellofemoral pain?

METHODS

Forty women with PFP were assessed with three-dimensional kinematic analyses during stair descent; isokinetic dynamometry of the knee extensors (isometric, concentric and eccentric); and the Tampa scale for kinesiophobia. Pearson coefficients were calculated to determine relationship among variables.

RESULTS

Kinesiophobia correlated significantly with cadence (r = -0.62, p < 0.001), and peak knee flexion (r = -0.76, p < 0.001). No significant correlations were found between any knee extensor strength variables and kinematics (cadence or peak knee flexion); or kinesiophobia (p > 0.05).

SIGNIFICANCE

Findings of this study could suggest addressing strength impairments alone may not adequately address kinesiophobia and movement pattern impairments in women with PFP. However, high-quality randomised controlled trials are needed to test this assumption. Further value may be added if currently evidence-based knee strengthening exercise is combined with education and/or graded exposure to address kinesiophobia, and consideration to gait retraining to address altered movement patterns at the knee.

The decline step-down test measuring the maximum pain-free flexion angle: A reliable and valid performance test in patients with patellofemoral pain

OBJECTIVES

Patients with patellofemoral pain (PFP) experience pain while descending stairs. To date no reliable and valid performance-test exists to assess the maximum pain-free knee flexion angle (MPFFA) as outcome measure during a step-down task. Therefore, the intra- and inter-observer reliability and construct validity of the decline step-down test (DSDT) measuring the MPFFA in patients with PFP were evaluated.

DESIGN

Reliability and construct validity.

SETTING

Private practices in Nijmegen and Utrecht, the Netherlands.

PARTICIPANTS

Patients with PFP.

MAIN OUTCOME MEASURES

The reliability was assessed by repeated measurements of the MPFFA during the DSDT. The construct validity was assessed by correlating the measurements on the DSDT with the Anterior Knee Pain Scale Dutch Version (AKPS-DV) based on a pre-set hypothesis.

RESULTS

Thirty-two participants (forty-eight knees) were eligible for inclusion. The intraclass correlation coefficient (ICC) for intra-observer reliability was ICC_2,1 = 0.83 and ICC_2,1 = 0.85 for inter-observer reliability. The 95% limits of agreement (LoA) showed a width of 27.56° for intra-observer reliability and a width of 24.42° for inter-observer reliability. There was an average positive correlation between the DSDT and the total score on the AKPS-DV (r_s = 0.31, p = 0.030).

CONCLUSION

The DSDT measuring the MPFFA is reliable and valid in patients with PFP.

Differences and mechanisms underpinning a change in the knee flexion moment while running in stability and neutral footwear among young females

Background

Higher peak external knee flexion moments (KFM) during running has been observed in healthy people wearing athletic footwear compared to barefoot, which may increase risk of knee pathologies such as patellofemoral pain. Currently, no studies have examined whether stability and neutral style athletic shoes influence the peak KFM differently, or explored the underlying biomechanical mechanisms by which footwear alters peak KFM in young females.

Methods

Lower limb biomechanics of sixty girls aged between 10 and 25 years old were collected while running in footwear (both stability and neutral) and barefoot. The external peak KFM, sagittal plane kinematics, sagittal plane knee ground reaction force (GRF) lever arm and sagittal plane resultant GRF magnitude were analysed by repeated measures Analysis of Variance. Linear mixed models were fit to identify predictors of a change in peak KFM, and to determine if the effects of these predictors differed between footwear conditions.

Results

The peak KFM was higher wearing both shoe styles compared to barefoot (p < 0.001), while no between-shoe differences were found (p > 0.05). Both shoes also increased kinematic variables at the hip, knee, and ankle (p < 0.05). When all these variables were entered into the mixed model, only a change in the knee-GRF lever arm was predictive of a change in peak KFM wearing shoes compared to barefoot (p < 0.001).

Conclusion

These findings provide evidence that stability and neutral shoes increase peak KFM compared to barefoot, which is associated with a change in the knee-GRF lever arm rather than a change in lower limb kinematics. Future studies may consider manipulating footwear characteristics to reduce the knee-GRF lever arm in an effort to reduce peak KFM and the potential risk of patellofemoral pain.

Electronic supplementary material

The online version of this article (10.1186/s13047-018-0307-9) contains supplementary material, which is available to authorized users.

Foot and ankle characteristics and dynamic knee valgus in individuals with patellofemoral osteoarthritis

Study design

Controlled laboratory study; cross-sectional design.

Background

Foot and ankle characteristics and dynamic knee valgus differ in people with and without patellofemoral (PF) pain. However, it is unknown if these characteristics are evident in people with PF osteoarthritis (OA), compared to pain-free older adults.

Objectives

To compare foot and ankle mobility, foot posture and dynamic knee valgus, measured as the frontal plane projection angle (FPPA) during single-leg squatting, between individuals with and without PFOA.

Methods

Fifty-one participants with PFOA (66% women, mean ± SD age 57 ± 10 years, body mass index (BMI) 27 ± 6 kg/m²), and 23 controls (56% women, age 56 ± 9 years, BMI 24 ± 4 kg/m²) had ankle dorsiflexion measured using the knee-to-wall test, foot mobility calculated as the difference in midfoot height or width between non-weightbearing and weightbearing, and static foot posture characterized utilizing the Foot Posture Index. Peak FPPA was determined from video recordings while participants performed 5 single-leg squats. Linear regressions examined between-groups relationships for foot and ankle characteristics and the FPPA.

Results

The PFOA group had less ankle dorsiflexion (odds ratio 6.7, 95% confidence interval 2.46-18.2), greater midfoot height mobility (5.2, 1.78-15.14) and width mobility (4.3, 1.33-14.39), and greater foot mobility magnitude (8.4, 2.32-30.69) than controls. There was no difference in FPPA (knee valgus angle) between groups (15, 0.63-377.99).

Conclusion

Foot and ankle characteristics were different in individuals with PFOA compared to control participants, however there was no difference in dynamic knee valgus during single leg squat. Clinical interventions to address greater foot mobility may be relevant for PFOA.

Are Patellofemoral Joint Alignment and Shape Associated With Structural Magnetic Resonance Imaging Abnormalities and Symptoms Among People With Patellofemoral Pain?

BACKGROUND

Patellofemoral malalignment has been observed among people with patellofemoral pain (PFP) and may be associated with the presence of imaging features of osteoarthritis, symptoms, and function.

PURPOSE

To determine whether patellofemoral joint alignment and bony shape are associated with (1) cartilage, bone, and soft tissue morphological abnormalities defined on magnetic resonance imaging (MRI) and (2) reported symptoms and function among people with PFP.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Participants (mean ± SD age, 30.2 ± 9.5 years; range, 14-50 years; 78 females, 58.6%) completed questionnaires regarding demographics, pain, symptoms, and function and underwent a 3-T MRI scan of their more symptomatic eligible knee. Structural MRI abnormalities were scored with the MOAKS (Magnetic Resonance Imaging Osteoarthritis Knee Score), and MRI alignment and shape were measured with standardized methods. Associations among MOAKS features, PFP symptoms, and alignment and shape measures were evaluated with regression analyses (α = .05).

RESULTS

Minor cartilage defects were present in 22 (16.5%) participants, patellar osteophytes in 83 (62.4%), anterior femur osteophytes in 29 (21.8%), Hoffa synovitis in 81 (60.9%), and prefemoral fat pad synovitis in 49 (36.8%). A larger Insall-Salvati ratio was significantly associated with the presence of patellar osteophytes (odds ratio [OR], 51.82; 95% CI, 4.20-640.01), Hoffa synovitis (OR, 60.37; 95% CI, 4.66-782.61), and prefemoral fat pad synovitis (OR, 43.31; 95% CI, 4.28-438.72) in the patellofemoral joint. A larger patellar tilt angle was significantly associated with the presence of minor cartilage defects (OR, 1.10; 95% CI, 1.00-1.20), the presence of patellar osteophytes (OR 1.12; 95%CI 1.02-1.22), and prefemoral fat pad synovitis (OR, 1.11; 95% CI, 1.03-1.20) in the patellofemoral joint. Finally, a larger bisect offset was significantly associated with the presence of minor cartilage defects (OR, 1.05; 95% CI, 1.00-1.11) and patellar osteophytes (OR, 1.07; 95% CI, 1.01-1.14) in the patellofemoral joint. The majority of patellofemoral alignment measures were not associated with symptoms or function.

CONCLUSION

For people with PFP, the presence of morphological abnormalities defined on MRI appears to be related to particular patellofemoral alignment measures, including higher Insall-Salvati ratio (indicating patella alta), larger patellar tilt angle (indicating greater lateral tilt), and larger bisect offset (indicating greater lateral displacement). Hardly any associations were found with symptoms or function. So there might be a distinct subgroup of PFP that is more prone to developing patellofemoral osteoarthritis later in life, as particular alignment measures seem to be associated with the presence of patellar osteophytes. Prospective studies are required to investigate the longitudinal relationship between alignment or bony shape and morphological abnormalities defined on MRI in this patient population.

Clinic-Based Patellar Mobilization Therapy for Knee Osteoarthritis: A Randomized Clinical Trial

PURPOSE

We performed a phase 2 randomized clinical trial to evaluate the preliminary effectiveness of a clinic-based patellar mobilization therapy (PMT) in patients with knee osteoarthritis.

METHODS

We recruited 208 patients with knee osteoarthritis at primary care clinics in Hong Kong. Patients were randomly assigned (1:1) to the intervention group or the control group. The intervention group received 3 PMT treatment sessions from primary care physicians at 2-month intervals, with concomitant prescription of a home-based vastus medialis oblique muscle exercise. The control group received PMT after the study period. The primary outcome was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score. Secondary outcomes included the WOMAC composite, function, and stiffness scores; the visual analog scale score for pain; objective physical function tests (30-s chair stand, 40-m walk test, timed up and go test, and EuroQol-5D). All outcomes were evaluated at baseline and at 24 weeks through intention-to-treat analysis.

RESULTS

We observed no baseline between-group differences. The WOMAC pain score showed greater improvement in the intervention group than in the control group at 24 weeks (between-group difference - 15.6, 95% CI, - 20.5 to - 10.7, P <.001). All secondary outcomes also demonstrated significant between-group differences.

CONCLUSIONS

Patellar mobilization therapy has the potential to reduce pain and improve function and quality of life for patients with knee osteoarthritis. Future clinical trials with comparison to other active comparator controls will help determine the overall efficacy and facilitate the deployment of PMT in real-world practice.

Relationship between knee abduction moment with patellofemoral joint reaction force, stress and self-reported pain during stair descent in women with patellofemoral pain

BACKGROUND

Increased external knee abduction moment has been proposed as a risk factor for patellofemoral pain. This alteration is thought to be associated with elevated patellofemoral joint reaction force and stress, however these relationships remain poorly explored. Therefore, this study aimed at comparing knee abduction moment parameters (peak, rate of moment development and impulse), patellofemoral joint reaction force and stress of women with patellofemoral pain and pain-free controls during stair descent; and investigating the relationship among these variables with self-reported pain.

METHODS

Kinetic data was obtained by inverse-dynamics equations and a previously reported algorithmic model was used to determine patellofemoral joint reaction force and stress. Participants' worst pain in the last month and pain level during stair descent were evaluated using a visual analogue scale.

FINDINGS

Women with patellofemoral pain presented higher peak, rate of moment development and impulse of the external knee abduction moment, patellofemoral joint reaction force and stress (p = 0.005 to 0.04, effect size = 0.52 to 0.96) during stair descent than pain-free controls. Only knee abduction moment impulse presented positive moderate correlations with worst pain level in the last month (r = 0.53, p < 000.1), pain level during stair descent (r = 0.33, p = 0.042), patellofemoral joint reaction force (r = 0.65, p < 000.1) and stress (r = 0.58, p < 000.1).

INTERPRETATION

These findings indicate that strategies aimed at decreasing external knee abduction moment impulse could reduce the load over the patellofemoral joint and improve pain of women with patellofemoral pain.

Quadriceps neuromuscular function in women with patellofemoral pain: Influences of the type of the task and the level of pain

The present study aimed at investigating whether the neuromuscular system behaves differently (in terms of force and muscle activity generation) as a function of the task being performed (i.e. maximal voluntary efforts vs stair negotiation) and the presence of patellofemoral pain (PFP) and possible influences of pain intensity. Thirty-eight women with (n = 19) and without PFP (n = 19) had their knee strength (extension joint torque) measured during maximal voluntary isometric contractions (MVIC) and electromyography (EMG) data recorded during both MVIC and stair ascent tasks, which were performed before and after a loading protocol designed to exacerbate pain symptoms. Women with PFP displayed lower levels of vastus medialis (p = 0.002) and vastus lateralis (p = 0.032) EMG activation during MVIC assessments. Conversely, the PFP group showed higher levels of vastus medialis muscle activity during stair climbing (p = 0.007), which happened exclusively after the loading protocol. Similarly, women with PFP displayed lower knee extensor torque only during the MVIC tests performed after the loading protocol, which was moderately correlated with the increase in self-reported pain (p = 0.041, r = 0.37), whereas the changes in EMG activity during stair ascent were not correlated with changes in pain intensity (p = 0.215, r = 0.12). These results suggest that, in comparison to pain-free controls, women with PFP display lower levels of quadriceps EMG activation during maximal contractions, but higher activation during dynamic tasks (stair ascent). In addition, the moderate association between the decrease in knee extensor torque and increase in self-reported pain indicates that care should be taken by clinicians during quadriceps strength evaluation in women with PFP, as misleading outcomes may emerge if the intensity of knee pain is not considered during screening. Additionally, rehabilitation strategies should focus on both restoring neuromuscular control and increasing muscle strength.

Two-dimensional frontal plane projection angle can identify subgroups of patellofemoral pain patients who demonstrate dynamic knee valgus

BACKGROUND

Identifying individuals with patellofemoral pain who demonstrate similar modifiable factors including dynamic knee valgus may be useful in establishing subgroups of patients that can undergo individualised management strategies. However, a lack of objective assessment criteria means that the findings are of limited value to clinicians aiming to distinguish between patients with and without altered frontal plane knee kinematics. Therefore, the aim of the study was to investigate dynamic knee valgus in individuals with and without patellofemoral pain by determining frontal plane knee alignment during functional activity.

METHODS

Thirty recreationally active individuals with patellofemoral pain and 30 non-injured individuals had frontal plane knee alignment assessed via two-dimensional analysis of the frontal plane projection angle during single limb stance and single limb squats to 60° of knee flexion.

FINDINGS

Individuals with patellofemoral pain demonstrated excessive frontal plane knee alignment (P = .003; ES = 0.68) compared to uninjured participants during single limb squats. In addition, assessing frontal plane knee alignment using two-dimensional analysis had fair specificity and sensitivity of discriminating patellofemoral pain injury.

INTERPRETATION

Clinical quantification of two-dimensional frontal plane knee alignment may be utilised to subgroup patients with patellofemoral pain that display dynamic knee valgus during single limb squats. Furthermore, this may be a useful clinical tool to determine individuals that may be at risk of developing pain in the future.

2018 International Consensus Statement on Golf and Health to guide action by people, policymakers and the golf industry

Scientific and public interest relating to golf and health has increased recently. Players, potential players, the golf industry and facilities, and decision makers will benefit from a better understanding of how to realise potential health benefits and minimise health issues related to golf. We outline an International Consensus on Golf and Health. A systematic literature review informed the development of a survey. Utilising modified Delphi methods, an expert panel of 25 persons including public health and golf industry leaders, took part in serial surveys providing feedback on suggested items, and proposing new items. Predefined criteria for agreement determined whether each item was included within each survey round and in the final consensus. The working group identified 79 scientifically supportable statement items from literature review and discussions. Twenty-five experts (100%) completed all three rounds of surveys, rating each item, and suggesting modifications and/or new items for inclusion in subsequent surveys. After three rounds, 83 items achieved consensus with each with >75% agreement and <10% disagreement. These items are included in the final International Consensus on Golf and Health. The final consensus presented here can inform scientific knowledge, and action plans for (1) golfers and potential golfers, (2) golf facilities and the golf industry, and (3) policy and decision makers external to golf. These outputs, if widely adopted, will contribute to an improved understanding of golf and health, and aid these groups in making evidence-informed decisions to improve health and well-being.

Risk factors for patellofemoral pain: a systematic review and meta-analysis

BACKGROUND

Patellofemoral pain (PFP) is a prevalent condition commencing at various points throughout life. We aimed to provide an evidence synthesis concerning predictive variables for PFP, to aid development of preventative interventions.

METHODS

We searched Medline, Web of Science and SCOPUS until February 2017 for prospective studies investigating at least one potential risk factor for future PFP. Two independent reviewers appraised methodological quality using the Newcastle-Ottawa Scale. We conducted meta-analysis where appropriate, with standardised mean differences (SMD) and risk ratios calculated for continuous and nominal scaled data.

RESULTS

This review included 18 studies involving 4818 participants, of whom 483 developed PFP (heterogeneous incidence 10%). Three distinct subgroups (military recruits, adolescents and recreational runners) were identified. Strong to moderate evidence indicated that age, height, weight, body mass index (BMI), body fat and Q angle were not risk factors for future PFP. Moderate evidence indicated that quadriceps weakness was a risk factor for future PFP in the military, especially when normalised by BMI (SMD -0.69, CI -1.02, -0.35). Moderate evidence indicated that hip weakness was not a risk factor for future PFP (multiple pooled SMDs, range -0.09 to -0.20), but in adolescents, moderate evidence indicated that increased hip abduction strength was a risk factor for future PFP (SMD 0.71, CI 0.39, 1.04).

CONCLUSIONS

This review identified multiple variables that did not predict future PFP, but quadriceps weakness in military recruits and higher hip strength in adolescents were risk factors for PFP. Identifying modifiable risk factors is an urgent priority to improve prevention and treatment outcomes.

Association of altered frontal plane kinematics and physical activity levels in females with patellofemoral pain

BACKGROUND

Females with patellofemoral pain (PFP) present with altered frontal plane kinematics, decreased physical activity, and elevated psychological features. However, the relationship between these factors has not been evaluated.

RESEARCH QUESTION

Does a relationship exist between frontal plane kinematics, physical activity levels, and fear avoidance beliefs in females with PFP.

METHODS

16 females with PFP (Age = 23.2 ± 4.9years; Height = 166.1 ± 5.9 cm; Mass = 66.3 ± 13.5 kg) completed a 3-D biomechanical assessment during a single leg squat, step-down, and jogging task. Physical activity was collected with an activity monitor over 2-weeks and the Fear Avoidance Belief Questionnaire physical activity subscale was used to assess fear avoidance beliefs. Frontal plane kinematics were correlated with physical activity and fear avoidance, with significant variables included in a multiple regression.

RESULTS

Significant correlations were identified between physical activity and single leg squat hip adduction (r=-0.626, p = 0.01), step-down knee abduction (r=-0.783, p < 0.001) and jogging hip adduction (r=-0.639, p = 0.008). Step-down knee abduction predicted activity level and accounted for 61% of the total variance. Correlations between fear avoidance belief and single leg squat hip adduction (r = 0.477, p = 0.049), step-down knee abduction (r = 0.644, p = 0.007), jogging knee abduction (r = 0.558, p = 0.025), and jogging hip adduction (r = 0.557, p = 0.025) were also identified. Knee abduction during the step-down and single leg squat hip adduction accounted for 37.5% of the variance in the Fear Avoidance Belief Questionnaire.

SIGNIFICANCE

Altered frontal plane kinematics during step-down and jogging provide insight for clinicians to identify females with patellofemoral pain that may be less physically active, while step-down and squatting kinematics related to fear avoidance beliefs. While these relationships were found, it is essential to identify the underlying mechanism for this activity modification so clinicians and researchers can evaluate successful interventions.

Patellar Tendon Reflex and Vastus Medialis Hoffmann Reflex Are Down Regulated and Correlated in Women With Patellofemoral Pain

OBJECTIVES

The aims of this study were threefold: (1) to compare the amplitude of patellar tendon reflex (T-reflex) between women with patellofemoral pain (PFP) and pain-free controls; (2) to compare the amplitude of vastus medialis Hoffmann reflex (VM H-reflex) between women with PFP and pain-free controls; (3) to investigate the association between the amplitude of patellar T-reflex and VM H-reflex in women with PFP and pain-free controls.

DESIGN

Cross-sectional observational study.

SETTING

Laboratory of biomechanics and motor control.

PARTICIPANTS

Thirty women with PFP and 30 pain-free women aged 18 to 35 years (N=60).

MAIN OUTCOME MEASURES

Peak-to-peak amplitudes of maximal VM H-reflex (elicited via electrical stimulation on the femoral nerve) and patellar T-reflex (elicited via mechanical percussion on the patellar tendon) were estimated.

RESULTS

Women with PFP had significant lower amplitude of patellar T-reflex (mean difference=0.086; 95% confidence interval=0.020 to 0.151; P=.010; moderate effect) and VM H-reflex (mean difference=0.150; 95% confidence interval =0.073 to 0.227; P<.001; large effect) compared to pain-free controls. The VM H-reflex was strongly correlated with patellar T-reflex in both PFP group (r=0.66; P<.001) and control group (r=0.72; P<.001).

CONCLUSIONS

As the T-reflex is easier to perform than H-reflex assessments in a clinical setting, it represents a feasible option to assess the impaired excitability of the stretch reflex pathway associated with PFP.

Implications of knee crepitus to the overall clinical presentation of women with and without patellofemoral pain

OBJECTIVES

Compare anthropometric characteristics, function, kinesiophobia, catastrophism and knee extensor strength between women (i) with PFP and crepitus (PFP_crepitus); (ii) with PFP and no crepitus (PFP_NOcrepitus); (iii) without PFP and crepitus (Pain-free_crepitus); and (iv) without PFP and no crepitus (Pain-free_NOcrepitus).

DESIGN

Cross-sectional.

SETTING

Laboratory study.

PARTICIPANTS

65 women with PFP and 51 pain-free women.

MAIN OUTCOME MEASURES

Objective assessment of knee crepitus, forward step-down and single leg hop tests; knee extensor strength tests; and subjective ratings of function, kinesiophobia, pain catastrophising and knee stiffness.

RESULTS

Crepitus was more common in women with PFP (50.7%) compared to those without (33.3%) (χ₍₁₎²=4.17;p=0.031). PFP_crepitus and PFP_NOcrepitus groups had lower self-reported function; and higher kinesiophobia, catastrophism and knee stiffness compared to Pain-free_crepitus and Pain-free_NOcrepitus groups (p < 0.001). PFP_crepitus, PFP_NOcrepitus and Pain-free_crepitus groups had lower functional performance compared to the Pain-free_NOcrepitus group (p < 0.040). PFP_crepitus and PFP_NOcrepitus groups had lower isometric, concentric and eccentric knee extensor strength compared to the Pain-free_NOcrepitus group (p < 0.041), but not the pain-free_crepitus group. PFP_crepitus presented higher BMI than other groups (p = 0.001).

CONCLUSION

Kinesiophobia, catastrophism, knee stiffness, strength and physical function are all impaired in women with PFP, regardless of crepitus. In pain-free women, crepitus was associated with poorer objective function.

2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017

Patellofemoral pain affects a large proportion of the population, from adolescents to older adults, and carries a substantial personal and societal burden. An international group of scientists and clinicians meets biennially at the International Patellofemoral Research Retreat to share research findings related to patellofemoral pain conditions and develop consensus statements using best practice methods. This consensus statement, from the 5th International Patellofemoral Research Retreat held in Australia in July 2017, focuses on exercise therapy and physical interventions (eg, orthoses, taping and manual therapy) for patellofemoral pain. Literature searches were conducted to identify new systematic reviews and randomised controlled trials (RCTs) published since the 2016 Consensus Statement. The methodological quality of included systematic reviews and RCTs was graded using AMSTAR and PEDro, respectively. Evidence-based statements were developed from included papers and presented to a panel of 41 patellofemoral pain experts for consensus discussion and voting. Recommendations from the expert panel support the use of exercise therapy (especially the combination of hip-focused and knee-focused exercises), combined interventions and foot orthoses to improve pain and/or function in people with patellofemoral pain. The use of patellofemoral, knee or lumbar mobilisations in isolation, or electrophysical agents, is not recommended. There is uncertainty regarding the use of patellar taping/bracing, acupuncture/dry needling, manual soft tissue techniques, blood flow restriction training and gait retraining in patients with patellofemoral pain. In 2017, we launched the International Patellofemoral Research Network (www.ipfrn.org) to consolidate and grow our patellofemoral research community, facilitate collaboration and disseminate patellofemoral pain knowledge to clinicians and the general public. The 6th International Patellofemoral Research Retreat will be held in Milwaukee, Wisconsin, USA, in October 2019.

Knee crepitus is prevalent in women with patellofemoral pain, but is not related with function, physical activity and pain

OBJECTIVES

(i) To assess the reliability of knee crepitus measures, (ii) to investigate the association between knee crepitus and PFP; (iii) to investigate the relationship between knee crepitus with self-reported function, physical activity and pain.

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

165 women with PFP and 158 pain-free women.

MAIN OUTCOME MEASURES

Knee crepitus test, anterior knee pain scale (AKPS) and self-reported worst knee pain in the last month, knee pain after 10 squats and knee pain after 10 stairs climbing.

RESULTS

Knee crepitus clinical test presented high reliability Kappa value for PFP group was 0.860 and for pain-free group was 0.906. There is a significantly greater proportion of those with crepitus in the PFP group than in the pain-free group (OR = 4.19). Knee crepitus had no relationship with function (rpb = 0.03; p = 0.727), physical activity level (rpb = 0.010; p = 0.193), worst pain (rpb = 0.11; p = 0.141), pain climbing stairs (rpb = 0.10; p = 0.194) and pain squatting (rpb = 0.02; p = 0.802).

CONCLUSION

Women who presents knee crepitus have 4 times greater odds to be in a group with PFP compared to those who do not. However, knee crepitus has no relationship with self-reported clinical outcomes of women with PFP.

Association between increase in vertical ground reaction force loading rate and pain level in women with patellofemoral pain after a patellofemoral joint loading protocol

BACKGROUND

The etiology of patellofemoral pain (PFP) is thought to be the result of increased patellofemoral joint (PFJ) load and aberrant lower extremity mechanics, including altered vertical ground reaction forces (VGRF). However, few studies have investigated the association between an increase in pain and VGRF loading rates in the context of PFP. Thus, this study aimed to investigate the immediate effects of PFJ loading on pain and VGRF loading rate, and to see if there is a link between modification of both pain and VGRF loading rate during stair negotiation.

METHODS

Thirty-four women with PFP underwent VGRF analysis during stair negotiation under two conditions: with (condition 2) and without (condition 1) being previously submitted to a PFJ loading protocol in order to or not to exacerbate their knee pain, respectively.

RESULTS

The VGRF loading rates were significantly higher in condition 2 (Mean ± standard deviation (SD)=4.0±0.6N/s) compared to condition 1 (Mean±SD=3.6±0.5N/s) during stair ascent and during stair descent (Mean±SD: condition 1=6.3±1.1N/s; condition 2=7.0±1.4N/s). In addition, VGRF loading rates were higher during stair descent compared to stair ascent in both conditions. There were significant correlations between the increase in pain and VGRF loading rate during both tasks.

CONCLUSION

There seemed to be an important relation between the increase in pain and VGRF loading rates in women with PFP. Based on these findings, interventions aimed at reducing VGRF loading rates are important in the context of PFP.

The effects & mechanisms of increasing running step rate: A feasibility study in a mixed-sex group of runners with patellofemoral pain

OBJECTIVES

To explore feasibility of recruitment and retention of runners with patellofemoral pain (PFP), before delivering a step rate intervention.

DESIGN

Feasibility study.

SETTING

Human performance laboratory.

PARTICIPANTS

A mixed-sex sample of runners with PFP (n = 11).

MAIN OUTCOME MEASURES

Average/worst pain and the Kujala Scale were recorded pre/post intervention, alongside lower limb kinematics and surface electromyography (sEMG), sampled during a 3 KM treadmill run.

RESULTS

Recruitment and retention of a mixed-sex cohort was successful, losing one participant to public healthcare and with kinematic and sEMG data lost from single participants only. Clinically meaningful reductions in average (MD = 2.1, d = 1.7) and worst pain (MD = 3.9, d = 2.0) were observed. Reductions in both peak knee flexion (MD = 3.7°, d = 0.78) and peak hip internal rotation (MD = 5.1°, d = 0.96) were observed, which may provide some mechanistic explanation for the identified effects. An increase in both mean amplitude (d = 0.53) and integral (d = 0.58) were observed for the Vastus Medialis Obliqus (VMO) muscle only, of questionable clinical relevance.

CONCLUSIONS

Recruitment and retention of a mixed sex PFP cohort to a step rate intervention involving detailed biomechanical measures is feasible. There are indications of both likely efficacy and associated mechanisms. Future studies comparing the efficacy of different running retraining approaches are warranted.

Immediate effects of a distal gait modification during stair descent in individuals with patellofemoral pain

Background: Knee pain during stair managing is a common complaint among individuals with PFP and can negatively affect their activities of daily living. Gait modification programs can be used to decrease patellofemoral pain. Immediate effects of a stair descent distal gait modification session that intended to emphasize forefoot landing during stair descent are described in this study. Objectives: To analyze the immediate effects of a distal gait modification session on lower extremity movements and intensity of pain in women with patellofemoral pain during stair descent. Method: Nonrandomized controlled trial. Sixteen women with patellofemoral pain were allocated into two groups: (1) Gait Modification Group (n = 8); and 2) Control Group (n = 8). The intensity of pain (visual analog scale) and kinematics of knee, ankle, and forefoot (multi-segmental foot model) during stair descent were assessed before and after the intervention. Results: After the gait modification session, there was an increase of forefoot eversion and ankle plantarflexion as well as a decrease of knee flexion. An immediate decrease in patellofemoral pain intensity during stair descent was also observed. Conclusion: The distal gait modification session changed the lower extremity kinetic chain strategy of movement, increasing foot and ankle movement contribution and decreasing knee contribution to the task. An immediate decrease in patellofemoral pain intensity during stair descent was also observed. To emphasize forefoot landing may be a useful intervention to immediately relieve pain in patients with patellofemoral pain during stair descent. Clinical studies are needed to verify the gait modification session effects in medium and long terms.

Inverted Rearfoot posture in subjects with coexisting patellofemoral osteoarthritis in medial knee osteoarthritis: an exploratory study

Background

While abnormal rearfoot posture and its relationship to patellofemoral (PF) pain has been thoroughly discussed in the literature, its relationship to patellofemoral osteoarthritis (PFOA) has not been determined. This study aimed to examine whether rearfoot posture is associated with a higher prevalence of radiographic PFOA in a compartment-specific manner in patients with medial tibiofemoral osteoarthritis (TFOA).

Methods

Participants from orthopedic clinics (n = 68, age 56–90 years, 75.0% female), diagnosed with radiographic medial TFOA (Kellgren/Lawrence [K/L] grade ≥ 2) were included in this study. The presence of PFOA and static rearfoot posture were evaluated using a radiographic skyline view and a footprint automatic measurement apparatus, respectively. The relationship between rearfoot posture and PFOA was examined using analysis of covariance and propensity score-adjusted logistic regression analysis.

Results

On average, patients with coexisting PFOA and medial TFOA (n = 39) had an inverted calcaneus 3.1° greater than those with isolated medial TFOA (n = 29). Increased calcaneus inverted angle was significantly associated with a higher probability of the presence of medial PFOA (odds ratio: 1.180, 95% confidence interval: [1.005, 1.439]; p = 0.043). Calcaneus inverted angle was not associated with higher odds of lateral PFOA presence based on the adjusted values.

Conclusions

The presence of an inverted rearfoot was associated with PFOA. Although these findings do not clearly indicate a biomechanical link between rearfoot posture and PFOA, this study shed light on the potential relationship between altered rearfoot posture and PFOA, as can be seen between rearfoot abnormality and PF pain.

Which is the best predictor of excessive hip internal rotation in women with patellofemoral pain: Rearfoot eversion or hip muscle strength? Exploring subgroups

BACKGROUND

Patellofemoral pain (PFP) has been linked to increased patellofemoral joint stress as a result of excessive hip internal rotation. Lower hip strength and/or excessive rearfoot eversion have been used to explain such altered movement pattern; however, it is unknown which one is the best predictor of excessive hip internal rotation.

RESEARCH QUESTION

To investigate if peak rearfoot eversion and/or peak concentric hip abductor strength can predict peak hip internal rotation during stair ascent in women with PFP.

METHODS

This cross-sectional study included thirty-seven women with PFP which underwent three-dimensional kinematic analysis during stair ascent and hip abductor strength analysis in an isokinetic dynamometer. A forced entry linear regression model analysis was carried out to determine which independent variables present the best capability to predict the hip internal rotation.

RESULTS

Peak concentric hip abductor strength significantly predicted peak hip internal rotation during stair ascent (R² = 0.27, p = 0.001). Peak rearfoot eversion did not predict peak hip internal rotation during stair ascent (R² < 0.01, p = 0.62). A Post-hoc analysis was conducted to explore if a subgroup with excessive rearfoot eversion would predict hip internal rotation. Based on a previous reported cut-off point, 48.6% of the participants were classified as excessive rearfoot eversion. For the subgroup with excessive rearfoot eversion, peak concentric hip abductor strength and peak rearfoot eversion significantly predicted peak hip internal rotation during stair ascent (R² = 0.26, p = 0.02; R² = 0.42, p = 0.003, respectively). For non-excessive rearfoot eversion subgroup, peak concentric hip abductor strength significantly predicted peak hip internal rotation during stair ascent (R² = 0.53; p < 0.001); and peak rearfoot eversion did not (R² = 0.01; p = 0.65).

SIGNIFICANCE

Findings indicate that hip muscle strength seems to be related with hip internal rotation in all women with PFP. Rearfoot eversion seems to be related with hip internal rotation only in a subgroup with excessive rearfoot eversion.

Arthroscopic Untethering of the Fat Pad of the Knee: Release or Resection of the Infrapatellar Plica (Ligamentum Mucosum) and Related Structures for Anterior Knee Pain

Anterior knee pain (AKP), a multifactorial symptom complex, can be successfully treated surgically. A specific diagnosis often cannot be made, but the pain is linked to an unrecognized common factor in most patients: the mechanical behavior of the non-isometric contents of the anterior compartment of the knee-the fat pad (FP) and infrapatellar plica (IPP). The objective of this presentation is to describe an effective arthroscopic technique that treats AKP by addressing this common factor. The operation consists of release or resection of the IPP, or ligamentum mucosum, which tethers the FP. These highly innervated tissues act together as a hydraulic shock absorber, filling the anterior compartment. They stretch and deform at the extremes of knee motion because of constraint centrally by the non-isometric IPP. These dynamic changes in shape are eliminated when the plica is released or resected. Pain perception is from perturbed nociceptive nerves: pain relief results from de-tensioning these contained nerves by untethering the fat pad. Ascribing pain causation is problematic because morphologic change, such as inflammation, fibrosis, or contracture of these structures, is only present in a minority of cases. Nonetheless, AKP is both physically linked to these central, pain-sensitive structures and relieved by this operation.

'If you can't help me, so help me God I will cut it off myself…' The experience of living with knee pain: a qualitative meta-synthesis

OBJECTIVE

To identify and explore the feelings and experiences of people living with knee pain as a precursor to exploring how this might contribute to improved care in the future.

DESIGN

The qualitative meta-synthesis was undertaken in three parts (1) a systematic search of the literature, (2) a critical appraisal of the relevant studies and (3) meta-aggregation of the findings from the selected studies. A qualitative meta-synthesis is a process that enables researchers to answer a specific research question by combining and summarising a variety of qualitative sources. This was undertaken using a contextualist approach which acknowledges different realities exist but tries to determine an underlying 'truth'.

SETTING

The participants from the selected studies were from a range of settings and ethnic groups, and cultural backgrounds.

PARTICIPANTS

There were nine articles included in the meta-synthesis. Articles focused on the experiences of surgery, return to sport, or other aspects of care were excluded.

RESULTS

No articles were excluded following critical appraisal. Eleven categories were identified from 55 findings which resulted in two synthesised findings being identified: knee pain affects every aspect of life and Searching for the best way forward.

LIMITATIONS

Articles were largely limited to older adults living with osteoarthritis. Many of the findings did not report demographic data. Only English language studies were included.

CONCLUSION

Many people living with knee pain struggle to adapt to living with knee pain and this is often exacerbated by a lack of knowledge and available information to help them plan for the future.

PROSPERO NO

CRD42017070227.

Hip kinematics during functional tasks in females with patellofemoral pain: Modification following rehabilitation and correlation with clinical improvement

OBJECTIVES

To compare hip kinematics during two functional tasks in females with and without patellofemoral pain (PFP), and to determine if hip kinematics and, symptoms and functional limitations were improved after a rehabilitation program.

DESIGN

Cross sectional and longitudinal.

PARTICIPANTS

Sixteen females with and 15 without PFP.

SETTING

Laboratory and physical therapy clinic.

MAIN OUTCOME MEASURES

Hip adduction (HADD) and medial rotation (HMR) peak angles, time integrals and inter-movement variability during step-down and vertical drop jump, symptoms and functional limitations evaluated using the Activities of Daily Living Scale of the Knee Outcome Survey (KOS-ADLS).

RESULTS

At baseline, no significant differences were found in step-down and vertical drop jump between PFP and controls. Following rehabilitation, significant improvements were reported in KOS-ADLS (p < 0.001). There was a significant decrease in HADD and HMR variability (p < 0.05), a trend for decreased peak HMR (p = 0.06) during step-down, and a significant decrease in HADD variability (p < 0.05) during vertical drop jump. These kinematic changes did not correlate with changes in KOS-ADLS (all p > 0.05).

CONCLUSION

Females with and without PFP demonstrated no hip kinematic differences during functional tasks. A rehabilitation program improved symptoms and functional status, and modified hip kinematics in females with PFP; however these changes were not correlated.

How to manage patellofemoral pain - Understanding the multifactorial nature and treatment options

Patellofemoral pain (PFP) is one of the most prevalent conditions within sports medicine, orthopaedic and general practice settings. Long-term treatment outcomes are poor, with estimates that more than 50% of people with the condition will report symptoms beyond 5 years following diagnosis. Additionally, emerging evidence indicates that PFP may be on a continuum with patellofemoral osteoarthritis. Consensus of world leading clinicians and academics highlights the potential benefit of delivering tailored interventions, specific to an individual's needs, to improve patient outcome. This clinical masterclass aims to develop the reader's understanding of PFP aetiology, inform clinical assessment and increase knowledge regarding individually tailored treatment approaches. It offers practical application guidance, and additional resources, that can positively impact clinical practice.

A 6-week hip muscle strengthening and lumbopelvic-hip core stabilization program to improve pain, function, and quality of life in persons with patellofemoral osteoarthritis: a feasibility pilot study

Background

Patellofemoral joint (PFJ) osteoarthritis (OA) is prevalent in middle-aged and older adults. Despite this, there are minimal studies which have examined conservative interventions for PFJ OA. Weakness of proximal lower extremity muscles is associated with PFJ OA. It is unknown if a hip muscle strengthening and lumbopelvic-hip core stabilization program will improve symptoms and function in persons with PFJ OA. This study examined the feasibility and impact of a 6-week hip muscle strengthening and core stabilization program on pain, symptoms, physical performance, peak muscle torques, and quality of life in persons with PFJ OA.

Methods

Ten females with PFJ OA and ten age- and sex-matched controls participated in baseline tests. PFJ OA participants attended ten twice-a-week hip strengthening and core stabilization exercise sessions. Outcome measures included questionnaires, the Timed-Up-and-Go, and peak isometric torque of hip and quadriceps muscles. Data were tested for normality; parametric and non-parametric tests were used as appropriate.

Results

At baseline, the PFJ OA group had significantly worse symptoms, slower Timed-Up-and-Go performance, and lower muscle torques than control participants. PFJ OA group adherence to supervised exercise sessions was adequate. All PFJ OA participants attended at least nine exercise sessions. Five PFJ OA participants returned 6-month follow-up questionnaires, which was considered fair retention. The PFJ OA participants' self-reported pain, symptoms, function in daily living, function in sport, and quality of life all improved at 6 weeks (P < 0.05). Timed-Up-and-Go time score improved at 6 weeks (P = 0.005). Peak hip external rotator torque increased (P = 0.01). Improvements in pain and self-reported function were no longer significant 6 months following completion of the intervention.

Conclusions

PFJ OA participants were adherent to the supervised sessions of the intervention. Improvement in symptoms, physical performance, and muscle torque were found after 6 weeks. Participant retention at 6 months was fair, and significant changes were no longer present. Our findings suggest that a hip strengthening and core stabilization program may be beneficial to improve symptoms, function, and physical performance in persons with PFJ OA. Future studies are needed, and additional measures should be taken to improve long-term adherence to exercise.

Trial registration

ClinicalTrials.gov NCT02825238. Registered 6 July 2016 (retrospectively registered).

DO MALES WITH PATELLOFEMORAL PAIN HAVE POSTEROLATERAL HIP MUSCLE WEAKNESS?

BACKGROUND

Patellofemoral pain is common in physically active adults. Females with patellofemoral pain have been shown to have posterolateral hip muscle weakness, but there is a paucity of research examining hip muscle strength in males with patellofemoral pain.

HYPOTHESIS/PURPOSE

The purpose of this study was to examine posterolateral hip muscle strength in males with patellofemoral pain compared to asymptomatic males. It was hypothesized that males with patellofemoral pain would have decreased strength of the hip extensor, hip external rotator, and hip abductor muscles compared to healthy, asymptomatic males.

STUDY DESIGN

Descriptive, cross-sectional.

METHODS

Thirty-six adult males with patellofemoral pain and 36 pain-free males participated in the study. The patellofemoral pain group were required to have retropatellar pain reproduced by activities that loaded the patellofemoral joint (squatting, descending stairs, etc.). Peak isometric torque of the hip extensors, hip external rotators, and hip abductors was measured with an instrumented dynamometer. Torque was normalized by body mass and height. Between-group differences were analyzed with parametric or non-parametric tests, as appropriate. The level of significance was adjusted for multiple comparisons.

RESULTS

Hip extensor torque was significantly reduced in the patellofemoral pain group compared to the control group (p = .0165). No differences were found between groups for the hip external rotators or hip abductors (p > .0167).

CONCLUSION

Males with patellofemoral pain appear to have weakness of the hip extensors, but unlike females with patellofemoral pain, they do not appear to have weakness of the hip abductors or hip external rotators. The findings of this study suggest that muscle strength factors associated with patellofemoral pain in males may be different from muscle strength factors in females. Clinicians examining and designing plans of care for male patients with patellofemoral pain should consider that the hip abductors and hip external rotators may not be weak in men with this condition.

LEVEL OF EVIDENCE

Level 3.

The effect of patellar taping on lower extremity running kinematics in individuals with patellofemoral pain syndrome

Purpose: To investigate the effects of patellar taping (Leukotape® (LT), Pinetown, South Africa, Kinesio Tape (KT), Dortmund, Germany, or no tape) on lower extremity kinematics in runners with and without patellofemoral pain syndrome (PFPS). Methods: In total, 20 healthy individuals and 12 with PFPS ran on a treadmill under different taping conditions and lower extremity kinematics and stride characteristics were obtained using Peak Motus Software, Colorado, USA. Data were analyzed using descriptive statistics and mixed factorial analysis of variance (p < 0.05). Results: Significant taping effects were found for hip (F(2,60) = 16.79, p = 0.0001) and knee (F(2,60) = 17.27, p = 0.0001) flexion angles at initial contact, and peak hip flexion angles during swing (F(2,60) = 6.55, p = 0.003). Increased flexion was noted with LT more than KT and no tape conditions. Similarly, peak knee flexion angles during stance (F(2,60) = 3.51, p = 0.03) and flight time (F(2,60) = 5.01, p = 0.01) revealed significant taping effects, with LT resulting in more flexion (p = 0.04) and shorter flight times (p = 0.01) than the no tape condition. Furthermore, a significant taping effect was seen for peak knee flexion angle during swing (F(2,60) = 4.96, p = 0.01), with the KT resulting in less flexion than LT (p = 0.04) and no tape conditions (p = 0.04). Conclusion: The application of tape during running may impact on hip and knee flexion angles at initial contact, as well as flight time.

The psychological features of patellofemoral pain: a cross-sectional study

Background and aims:

Patellofemoral pain (PFP) is a prevalent and debilitating musculoskeletal condition, considered to have a mechanical aetiology. As such, the physical impairments associated with PFP are well documented and have helped characterise different physical phenotypes. But little is known about the relationship between PFP and psychological well-being. In this study, we aimed to: (1) compare psychological profiles between groups with and without PFP; (2) compare psychological profiles and condition severity between PFP subgroups; and (3) explore relationships between psychological factors and their contribution to disability. We expected to find higher levels of psychological impairment, especially kinesiophobia and catastrophizing in the PFP group. We also expected to identify a sub-group for who worsening levels of disability correspond with worsening psychological well-being.

Methods:

One hundred participants with PFP (72 females, mean±SD age 27±5 years, BMI 25.3±4.8 kg/m2) completed measures of pain, disability, and psychological features (kinesiophobia, catastrophizing, anxiety and depression). Fifty controls, matched by sex, age and activity level (36 females, age 27±5 years, BMI 22.9±4.5 kg/m2) also completed psychological measures. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used to cluster PFP participants (K-means cluster analysis) into more and less severe sub-groups. Differences between the control and PFP groups were analysed using t-tests, analysis of variance, Mann-Whitney U-tests or χ 2 tests as appropriate (p<0.05). Pearson correlations were used to explore relationships between psychological measures. Backward stepwise regression (p out >0.05) evaluated how the psychological factors potentially relate to disability.

Results:

Psychological features did not differ between PFP and pain-free groups. But differences were apparent when the PFP cohort was subgrouped. Compared to controls, the more-severe group had significantly higher levels of depression (MD 1.8, 95% CI 0.8–2.8; p≤0.001) and catastrophizing (MD 5.7, 95% CI 2.4–9; p≤0.001). When compared to less-severe cases, the more-severe group also demonstrated significantly higher levels of kinesiophobia (MD 4.3, 95% CI 2.1–6.5; p≤0.001), depression (MD 1.5 95% CI 0.5–2.6; p=0.01) and catastrophizing (MD 4.9, 95% CI 1–8.8; p=0.01). The weakest relationship between psychological factors was found between kinesiophobia and anxiety (r=0.29; p=0.02). While the strongest relationship existed between depression and anxiety (r=0.52; p≤0.001). Both kinesiophobia (β −0.27, 95% CI −0.265 to −0.274) and depression (β −0.22, 95% CI −0.211 to −0.228) were associated with disability as defined by the KOOS in the regression model (R 2=0.17, p≤0.001).

Conclusions:

Those with more-severe PFP-related disability have higher levels of psychological impairment than less-severe cases. Kinesiophobia seems to stand as an important factor in the experience of PFP, because it was elevated in the PFP group, significantly differed between the PFP sub-groups and contributed to explaining disability. Contrary to our hypothesis, levels of catastrophizing in the PFP group and severe sub-group were low and seemingly not important.

Implications:

These findings draw attention to psychological factors to which clinicians assessing PFP should show vigilance. They also highlight psychological impairments that might be worthwhile targets in optimising PFP management.

Clinical effectiveness of patella mobilisation therapy versus a waiting list control for knee osteoarthritis: a protocol for a pragmatic randomised clinical trial

INTRODUCTION

Knee osteoarthritis (KOA) is a common, disabling and costly medical condition. The patellofemoral joint is a critical source of pain in individuals with KOA, and coexistence of patellofemoral osteoarthritis (PFOA) and tibiofemoral osteoarthritis (TFOA) is sometimes observed. The identification of subgroups with PFOA and customised interventions to correct underlying pathomechanics is beneficial for individuals with KOA. This study aims to evaluate whether a clinic-based patella mobilisation therapy (PMT) leads to significant improvement in pain, physical function and quality of life of individuals with KOA.

METHODS AND ANALYSIS

A total of 208 participants with coexistence of PFOA and TFOA will be recruited. A pragmatic randomised clinical trial will be conducted, and participants will be randomised into the PMT and waiting list groups. For the PMT group, three manual mobilisation sessions, along with home-based vastus medialis oblique muscle exercise, will be conducted at 2-month intervals. The waiting list group will continue to receive their usual care, and as an incentive the waiting list group will be offered PMT after the study period is over. The primary outcome is the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale, and secondary outcomes include the WOMAC function and stiffness subscales, scores for objective physical function tests (the 30 s chair stand, 40-metre fast-paced walk test, the Timed Up and Go Test), and the EuroQol-5D scores. All outcomes will be evaluated at baseline and 6 months using intention-to-treat and incorporating covariate analysis.

ETHICS AND DISSEMINATION

Ethics approval has been obtained (CREC no: 2014.379). Results of the trial will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR-IPC-15006618; Pre-results.

Capturing patient-reported area of knee pain: a concurrent validity study using digital technology in patients with patellofemoral pain

BACKGROUND

Patellofemoral pain (PFP) is often reported as a diffuse pain at the front of the knee during knee-loading activities. A patient's description of pain location and distribution is commonly drawn on paper by clinicians, which is difficult to quantify, report and compare within and between patients. One way of overcoming these potential limitations is to have the patient draw their pain regions using digital platforms, such as personal computer tablets.

OBJECTIVE

To assess the validity of using computer tablets to acquire a patient's knee pain drawings as compared to paper-based records in patients with PFP.

METHODS

Patients (N = 35) completed knee pain drawings on identical images (size and colour) of the knee as displayed on paper and a computer tablet. Pain area expressed as pixel density, was calculated as a percentage of the total drawable area for paper and digital records. Bland-Altman plots, intraclass correlation coefficient (ICC), Pearson's correlation coefficients and one-sample tests were used in data analysis.

RESULTS

No significant difference in pain area was found between the paper and digital records of mapping pain area (p = 0.98), with the mean difference = 0.002% (95% CI [-0.159-0.157%]). A very high agreement in pain area between paper and digital pain drawings (ICC = 0.966 (95% CI [0.93-0.98], F = 28.834, df = 31, p < 0.001). A strong linear correlation (R2 = 0.870) was found for pain area and the limits of agreement show less than ±1% difference between paper and digital drawings.

CONCLUSION

Pain drawings as acquired using paper and computer tablet are equivalent in terms of total area of reported knee pain. The advantages of digital recording platforms, such as quantification and reporting of pain area, could be realized in both research and clinical settings.

Age-related differences in foot mobility in individuals with patellofemoral pain

Background

Age-related changes in midfoot mobility have the potential to influence success with foot orthoses intervention in people with patellofemoral pain (PFP). The aim of this study was to determine whether older people with PFP demonstrate less foot mobility than younger adults with PFP.

Methods

One hundred ninety four participants (113 (58%) women, age 32 ± 7 years, BMI 25 ± 4.9 kg/m²) with PFP (≥ 6 weeks duration) were included, with foot mobility quantified using reliable and valid methods. K-means cluster analysis classified participants into three homogenous groups based on age. After cluster formation, univariate analyses of co-variance (covariates: sex, weight) were used to compare midfoot height mobility, midfoot width mobility, and foot mobility magnitude between age groups (significance level 0.05).

Results

Cluster analysis revealed three distinct age groups: 18–29 years (n = 70); 30–39 years (n = 101); and 40–50 years (n = 23). There was a significant main effect for age for midfoot height mobility (p < 0.001) and foot mobility magnitude (p = 0.006). Post-hoc analyses revealed that midfoot height mobility differed across all three groups (moderate to large effect sizes), and that foot mobility magnitude was significantly less in those aged 40–50 years compared to those aged 18–25 years (moderate effect size). There were no significant main effects for age for midfoot width mobility (p > 0.05).

Conclusion

Individuals with PFP aged 40–50 years have less foot mobility than younger adults with PFP. These findings may have implications for evaluation and treatment of older individuals with PFP.

Predictors of clinical success in runners with patellofemoral pain: Secondary analyses of a randomized clinical trial

OBJECTIVES

To identify predictors of outcome to a rehabilitation program focused on education and management of training loads in runners with patellofemoral pain (PFP).

DESIGN

Secondary analyses of a randomized clinical trial.

METHODS

Fifty-eight runners with PFP (62% female, aged 31.2±6.6years, running 20.3±5.6km/week) were included in analyses. Following baseline collection of demographics, anthropometry, symptomatology, isometric strength, running mechanics and radiological data, runners were randomized to one of the three 8-week intervention program: (1) Education on symptoms management and training modifications; (2) Education+Exercise program; (3) Education+Gait retraining. Clinical success was defined as an increase ≥13.6% on the Knee Outcome Survey - Activities of Daily Living Scale (KOS-ADLS) at 3 months following program completion. Potential predictors were entered into logistic regression analyses.

RESULTS

Forty-five runners (78%) were categorized as Success. Together, KOS-ADLS score (<70%), knee extension isometric strength (<70% bodyweight), presence of patellar tendinopathy (Grade >0) and level of usual pain (>2/10) at baseline predicted treatment outcome with 87.9% accuracy. The model provided sensitivity of 0.93 (95% C.I. 0.82-0.98), specificity of 0.69 (95% C.I. 0.42-0.87), positive likelihood ratio of 3.0 (95% C.I. 1.3-6.9), and negative likelihood ratio of 0.1 (95% C.I. 0-0.3). The best individual predictors were KOS-ADLS score and knee extension strength.

CONCLUSIONS

The combination of KOS-ADLS, knee extensors strength, patellar tendon integrity and usual pain best predicted clinical outcome of runners with PFP following an intervention that had a common education component. Further testing is needed before a clinical prediction rule can be recommended to clinicians.

Ultrasonography findings and physical examination outcomes in dancers with and without patellofemoral pain

OBJECTIVES

To identify whether a physical examination for patello-femoral pain (PFP) is related to ultrasonography findings at the knee, and to identify possible factors related to PFP in young dancers.

METHODS

Sixty-seven young female dancers (7th grade, aged 12.8 ± 0.5) from three schools with identical special dance programs were included in the study. All the dancers were interviewed for demographic details, dance background, and training intensity; were evaluated for anthropometric measurements; underwent physical examination of both knees for PFP and for knee range of motion (ROM); and, had ultrasonography assessment for pathologies and of anatomical parts of their knees.

RESULTS

PFP was found in 54.5% of the 134 knees physically examined. In ultrasonography assessment, infra-articular effusion was found in 46.2% of the knees examined. H/week of dance practice was significantly higher among dancers with PFP (in both knees) compared with dancers with no PFP (p < .05). Knees with PFP had a significantly higher prevalence of intra articular effusion (p = .018) and higher prevalence of genu-recurvatum (p = .042). Knees with PFP had significantly greater growth plate width-anterior tibial tuberosity (p = .022) and a greater bony trochlear groove angle (p = .048).

CONCLUSION

This study describes the relationship between physical examination for PFP and the sonographic findings, and the factors related to knee injuries. The results showed a high prevalence of PFP and intra articular knee effusion among young dancers at the age of 12-13 years; and, that the number of hours of practice and anatomical structure are related to PFP. Our results should alert physicians, physiotherapists, athletic trainers and dance teachers to the need for devising modifications of training and injury prevention strategies from a young age (<12 years old).

The experience of living with patellofemoral pain-loss, confusion and fear-avoidance: a UK qualitative study

OBJECTIVES

To investigate the experience of living with patellofemoral pain (PFP).

DESIGN

Qualitative study design using semistructured interviews and analysed thematically using the guidelines set out by Braun and Clarke.

SETTING

A National Health Service physiotherapy clinic within a large UK teaching hospital.

PARTICIPANTS

A convenience sample of 10 participants, aged between 18 and 40 years, with a diagnosis of PFP and on a physiotherapy waiting list, prior to starting physiotherapy.

RESULTS

Participants offered rich and detailed accounts of the impact and lived experience of PFP, including loss of physical and functional ability; loss of self-identity; pain-related confusion and difficulty making sense of their pain; pain-related fear, including fear-avoidance and 'damage' beliefs; inappropriate coping strategies and fear of the future. The five major themes that emerged from the data were: (1) impact on self; (2) uncertainty, confusion and sense making; (3) exercise and activity beliefs; (4) behavioural coping strategies and (5) expectations of the future.

CONCLUSIONS

These findings offer an insight into the lived experience of individuals with PFP. Previous literature has focused on pain and biomechanics, rather than the individual experience, attached meanings and any wider context within a sociocultural perspective. Our findings suggest that future research is warranted into biopsychosocial targeted interventions aimed at the beliefs and pain-related fear for people with PFP. The current consensus that best-evidence treatments consisting of hip and knee strengthening may not be adequate to address the fears and beliefs identified in the current study. Further qualitative research may be warranted on the impact and interpretation of medical terminology commonly used with this patient group, for example, 'weakness' and 'patellar mal-tracking' and its impact and interpretation by patients.

TRIAL REGISTRATION NUMBER

ISRCTN35272486; Pre-results.

Incidence and prevalence of patellofemoral pain: A systematic review and meta-analysis

BACKGROUND

Patellofemoral pain is considered one of the most common forms of knee pain, affecting adults, adolescents, and physically active populations. Inconsistencies in reported incidence and prevalence exist and in relation to the allocation of healthcare and research funding, there is a clear need to accurately understand the epidemiology of patellofemoral pain.

METHODS

An electronic database search was conducted, as well as grey literature databases, from inception to June 2017. Two authors independently selected studies, extracted data and appraised methodological quality. If heterogeneous, data were analysed descriptively. Where studies were homogeneous, data were pooled through a meta-analysis.

RESULTS

23 studies were included. Annual prevalence for patellofemoral pain in the general population was reported as 22.7%, and adolescents as 28.9%. Incidence rates in military recruits ranged from 9.7-571.4/1,000 person-years, amateur runners in the general population at 1080.5/1,000 person-years and adolescents amateur athletes 5.1%-14.9% over 1 season. One study reported point prevalence within military populations as 13.5%. The pooled estimate for point prevalence in adolescents was 7.2% (95% Confidence Interval: 6.3%-8.3%), and in female only adolescent athletes was 22.7% (95% Confidence Interval 17.4%-28.0%).

CONCLUSION

This review demonstrates high incidence and prevalence levels for patellofemoral pain. Within the context of this, and poor long term prognosis and high disability levels, PFP should be an urgent research priority.

PROSPERO REGISTRATION

CRD42016038870.