Is markerless, smart phone recorded two-dimensional video a clinically useful measure of relevant lower limb kinematics in runners with patellofemoral pain? A validity and reliability study
Design: Validity/reliability study.
Setting: Biomechanics laboratory.
Participants: Males/females with PFP (n = 21, 10 males, 11 females, age 32.1 months [±12.9]).
Main outcome measures: Manually synchronised 2D and 3D measurement of peak hip adduction (HADD) and peak knee flexion (KFLEX) during running.
Results: 2D and 3D measures of peak KFLEX (p = 0.02, d = 1.13), but not peak HADD (p = 0.25, d = −0.27), differed significantly. Poor validity was identified for 2D measurement of peak HADD (ICC 0.06, 95% CI -0.35, 0.47) and peak KFLEX ICC 0.42, 95% CI (−0.10, 0.75). Moderate intra-rater reliability was identified for both variables (ICC 0.61–65), alongside moderate inter-rater reliability for peak KFLEX (ICC 0.71) and poor inter-rater reliability for peak HADD (ICC 0.31).
Conclusions: Measurement of peak HADD and KFLEX in runners with PFP using markerless, smart phone collected 2D video, analysed using the Hudl technique Application is invalid, with poor to moderate reliability. Investigation of alternate 2D video approaches to increase precision is warranted. At present, 2D video analysis of running using Hudl Technique cannot be advocated.
Two Weeks of Wearing a Knee Brace Compared With Minimal Intervention on Kinesiophobia at 2 and 6 Weeks in People With Patellofemoral Pain: A Randomized Controlled Trial
Design: Single-blind randomized controlled trial (1:1), parallel.
Participants: Individuals with PFP (N=50).
Main Outcome Measures: Primary - kinesiophobia (Tampa Scale for Kinesiophobia). Secondary - self-reported function (Anterior Knee Pain Scale), physical activity level (International Physical Activity Questionnaire), and objective function (forward step-down test). Outcomes were assessed at baseline (T0), at the end of the intervention (2wk) (T1), and at 6 weeks after baseline (T2).
Intervention: Participants were randomly assigned to 1 of 2 interventions groups: (1) use of knee brace for 2 weeks during daily living, sports, or painful tasks (brace group) and (2) educational leaflet with information about PFP (leaflet group).
Results: The knee brace reduced kinesiophobia in people with PFP compared with minimal intervention with moderate effect size at T1=mean difference (95% CI) −5.56 (−9.18 to −1.93) and T2=−5.24 (−8.58 to −1.89). There was no significant difference in self-reported and objective function and physical activity level.
Conclusions: The knee brace improved kinesiophobia immediately after intervention (at 2wk) and at 6-week follow-up in people with PFP compared with minimal intervention. A knee brace may be considered within clinically reasoned paradigms to facilitate exercise therapy interventions for people with PFP.
Gait Retraining as an Intervention for Patellofemoral Pain
Recent Findings: The majority of studies reviewed demonstrated some improvement in patellofemoral pain symptoms and overall function. However, the degree of improvement as well as the persistence of improvement over time varied between studies. The greatest pain reduction and persistent changes were noted in those studies that incorporated a faded feedback design including between 8 and 18 sessions over 2–6 weeks, typically 3–4 sessions per week. Additionally, dosage in these studies increased to 30–45 min during later sessions, resulting in 177–196 total minutes of retraining. In contrast, pain reductions and persistence of changes were the least in studies where overall retraining volume was low and feedback was either absent or continual.
Summary: Faulty movement patterns have been associated with patellofemoral pain. Studies have shown that strengthening alone does not alter these patterns, and that addressing the motor program is needed to effect these changes. Based upon the studies reviewed here, retraining faulty patterns, when present, appears to play a significant role in addressing patellofemoral pain. Therefore, movement retraining, while adhering to basic motor control principles, should be part of a therapist’s intervention skillset when treating patients with PFP.
Altered pain processing and sensitisation is evident in adults with patellofemoral pain: a systematic review including meta-analysis and meta-regression
Methods: The protocol was prospectively registered with PROSPERO (CRD42019129851). PubMed, CINAHL, Web of Science and EMBASE were systematically searched from inception to April 2019 for studies investigating pain processing in PFP patients compared to controls using quantitative sensory testing. Each included paper was assessed for methodological quality using a modified version of Downs and Black. Means and standard deviations were extracted to calculate standardised mean differences (SMD) and 95% confidence intervals (95% CI). Where possible meta-analysis and meta-regression were performed using a random effects model.
Results: Eleven studies were identified, two medium and nine high quality. Meta-analysis indicates moderate evidence for decreased pressure pain thresholds (SMD −0.68, 95% CI −0.93 to −0.43), increased tactile detection thresholds (SMD 1.35, 95% CI 0.49–2.22) and increased warmth detection thresholds (SMD 0.61, 95% CI 0.30–0.92) in PFP patients compared to controls. Secondary analysis indicates moderate evidence for decreased pressure pain thresholds in female compared to male patients (SMD −0.75, 95% CI −1.34 to −0.16). Meta-regression indicates a moderate correlation between decreasing local and distal pressure pain thresholds and decreasing patient age (local R2 = 0.556, p = 0.0211; distal R2 = 0.491, p = 0.0354) but no correlation with symptom duration (p > 0.05).
Conclusions: Evidence from this systematic review with meta-analysis and meta-regression appears to suggest the presence of altered pain processing and sensitisation in patients with PFP with increased sensitivity indicated in female patients and younger patients.
Implications: With evidence of altered pain processing and sensitisation in PFP, it may be beneficial for clinicians to consider management approaches that aim specifically at adressing neuropathic pain, for example neuroscience education, to improve patients outcomes. With female patients and younger patients indicated as experiencing greater degree of sensitivity, this may be a good demographic to start screening for sensitisation, in order to better identify and treat those most affected.
Pressure pain thresholds in adults with patellofemoral pain and patellofemoral joint osteoarthritis: a case-control study
Methods: 13 PFP patients plus 20 matched controls and 15 PFJOA patients plus 34 matched controls were recruited from a UK mixed-sex adult population. Controls were matched on age, sex and activity level. Demographic details, Tegner activity level score, symptom duration, condition severity (Kujala and KOOS-PF scores for PFP and PFJOA, respectively) and knee function (Modified Whatman score rating of five single leg squats) were recorded. PPTs were measured at six sites: five local around the knee, one remote on the contralateral leg. Between-group differences were tested using a two-way mixed model analysis of variance with repeated measures. Strength of association between PPTs and condition severity and knee function were tested using Spearman’s rank order correlation.
Results: No statistically significant difference in PPTs were observed between the PFP patients [F(1,31) = 0.687, p = 0.413, η2 = 0.022] or PFJOA patients [F(1,47) = 0.237, p = 0.629, η2 = 0.005] and controls. Furthermore, no correlation was found between PPTs and condition severity or knee function in PFP or PFJOA (p > 0.05).
Conclusions: Results suggest mechanical pain sensitisation is not a dominant feature of UK mixed-sex adults with PFP or PFJOA.
Implications: PFP and PFJOA remain persistent pain complaints which may not be well explained by objective measures of sensitivity such as PPTs. The findings suggest that peripheral pain processing changes leading to pain sensitisation is not a key feature in PFP or PFJOA. Instead the underlying pain pathway is likely to remain primary nociceptive, possibly with a subgroup of patients who experience pain sensitisation and might benefit from a more targeted management approach.
Increased hip adduction during running is associated with patellofemoral pain and differs between males and females: A case-control study
Risk factors for patellofemoral pain: a systematic review & meta-analysis.
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.
Medial and Lateral Patellofemoral Joint Retinaculum Thickness in People With Patellofemoral Pain: A Case‐Control Study
Methods: Medial and lateral patellofemoral joint retinaculum thicknesses of 32 knees (16 with patellofemoral pain and 16 asymptomatic) were measured with B‐mode ultrasound at 0.5, 1, and 1.5 cm from the patella border. Participants with patellofemoral pain completed a Kujala questionnaire, and both groups underwent a single‐leg squat performance assessment. Two‐way analyses of variance (site × group) determined the overall effect, and Cohen d values were calculated to describe the magnitude of the difference for each measurement.
Results: The groups were matched for age, height, and weight. Compared to controls, participants with patellofemoral pain had thicker lateral (overall effect, P = .03) and medial (overall effect, P < 0.01) retinacula. No correlations between retinaculum thickness and Kujala scores (lateral retinaculum, r = 0.106 [0.5 cm], –0.093 [1 cm], and –0.207 [1.5 cm]; and medial retinaculum, r = 0.059, 0.109, and –0.219), symptom duration (lateral retinaculum, r = 0.001, –0.041, and 0.302; and medial retinaculum, r = –0.027, –0.358, and –0.346), or single‐leg squat performance scores (lateral retinaculum, r = 0.051, 0.114, and 0.046; and medial retinaculum, r = –0.119, –0.292, and 0.011) were observed.
Conclusions: Increased lateral and medial retinaculum thickness in individuals with patellofemoral pain compared to controls identifies structural changes that may be associated with the pathogenesis of patellofemoral pain. The absence of a significant correlation between retinaculum thickness and the symptom duration or function further shows a lack of an association between structure and function in individuals with patellofemoral pain.
How to manage patellofemoral pain – Understanding the multifactorial nature and treatment options
The effects & mechanisms of increasing running step rate: A feasibility study in a mixed-sex group of runners with patellofemoral pain
Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis
Running retraining to treat lower limb injuries: a mixed-methods study of current evidence synthesised with expert opinion
Objective: Synthesise published evidence with international expert opinion on the use of running retraining when treating lower limb injuries.
Design: Mixed methods.
Methods: A systematic review of clinical and biomechanical findings related to running retraining interventions were synthesised and combined with semistructured interviews with 16 international experts covering clinical reasoning related to the implementation of running retraining.
Results: Limited evidence supports the effectiveness of transition from rearfoot to forefoot or midfoot strike and increase step rate or altering proximal mechanics in individuals with anterior exertional lower leg pain; and visual and verbal feedback to reduce hip adduction in females with patellofemoral pain. Despite the paucity of clinical evidence, experts recommended running retraining for: iliotibial band syndrome; plantar fasciopathy (fasciitis); Achilles, patellar, proximal hamstring and gluteal tendinopathy; calf pain; and medial tibial stress syndrome. Tailoring approaches to each injury and individual was recommended to optimise outcomes. Substantial evidence exists for the immediate biomechanical effects of running retraining interventions (46 studies), including evaluation of step rate and strike pattern manipulation, strategies to alter proximal kinematics and cues to reduce impact loading variables.
Summary and relevance: Our synthesis of published evidence related to clinical outcomes and biomechanical effects with expert opinion indicates running retraining warrants consideration in the treatment of lower limb injuries in clinical practice.
Proximal muscle rehabilitation is effective for patellofemoral pain: a systematic review with meta-analysis
The ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’: incorporating level 1 evidence with expert clinical reasoning
Objective: Develop a comprehensive contemporary guide to conservative management of PFP outlining key considerations for clinicians to follow.
Design: Mixed methods.
Methods: We synthesised the findings from six high-quality systematic reviews to September 2013 with the opinions of 17 experts obtained via semistructured interviews. Experts had at least 5 years clinical experience with PFP as a specialist focus, were actively involved in PFP research and contributed to specialist international meetings. The interviews covered clinical reasoning, perception of current evidence and research priorities.
Results: Multimodal intervention including exercise to strengthen the gluteal and quadriceps musculature, manual therapy and taping possessed the strongest evidence. Evidence also supports use of foot orthoses and acupuncture. Interview transcript analysis identified 23 themes and 58 subthemes. Four key over-arching principles to ensure effective management included—(1) PFP is a multifactorial condition requiring an individually tailored multimodal approach. (2) Immediate pain relief should be a priority to gain patient trust. (3) Patient empowerment by emphasising active over passive interventions is important. (4) Good patient education and activity modification is essential. Future research priorities include identifying risk factors, testing effective prevention, developing education strategies, evaluating the influence of psychosocial factors on treatment outcomes and how to address them, evaluating the efficacy of movement pattern retraining and improving clinicians’ assessment skills to facilitate optimal individual prescription.
Conclusions and relevance: Effective management of PFP requires consideration of a number of proven conservative interventions. An individually tailored multimodal intervention programme including gluteal and quadriceps strengthening, patellar taping and an emphasis on education and activity modification should be prescribed for patients with PFP. We provide a ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’ outlining key considerations.
Dynamic foot function as a risk factor for lower limb overuse injury: a systematic review
Methods: A systematic search was performed using Medline, CINAHL, Embase and SportDiscus in April 2014 to identify prospective cohort studies that utilised dynamic methods of foot assessment. Included studies underwent methodological quality appraisal by two independent reviewers using an adapted version of the Epidemiological Appraisal Instrument (EAI). Effects were expressed as standardised mean differences (SMD) for continuous scaled data, and risk ratios (RR) for nominal scaled data.
Results: Twelve studies were included (total n = 3,773; EAI 0.44 to 1.20 out of 2.00, representing low to moderate quality). There was limited to very limited evidence for forefoot, midfoot and rearfoot plantar loading variables (SMD 0.47 to 0.85) and rearfoot kinematic variables (RR 2.67 to 3.43) as risk factors for patellofemoral pain; and plantar loading variables (forefoot, midfoot, rearfoot) as risk factors for Achilles tendinopathy (SMD 0.81 to 1.08). While there were significant findings from individual studies for plantar loading variables (SMD 0.3 to 0.84) and rearfoot kinematic variables (SMD 0.29 to 0.62) as risk factors for ‘non-specific lower limb overuse injuries’, these were often conflicting regarding different anatomical regions of the foot. Findings from three studies indicated no evidence that dynamic foot function is a risk factor for iliotibial band syndrome or lower limb stress fractures.
Conclusion: This systematic review identified very limited evidence that dynamic foot function during walking and running is a risk factor for patellofemoral pain, Achilles tendinopathy, and non-specific lower limb overuse injuries. It is unclear whether these risk factors can be identified clinically (without sophisticated equipment), or modified to prevent or manage these injuries. Future prospective cohort studies should address methodological limitations, avoid grouping different lower limb overuse injuries, and explore clinically meaningful representations of dynamic foot function.
Foot posture as a risk factor for lower limb overuse injury: a systematic review and meta-analysis
The immediate effects of foot orthoses on hip and knee kinematics and muscle activity during a functional step-up task in individuals with patellofemoral pain
Methods: Hip muscle activity and kinematics were measured during a step-up task with and without an anti-pronating foot orthoses, in people (n = 20, 9 M, 11 F) with patellofemoral pain. Additionally, we measured knee function, foot posture index, isometric hip abductor and knee extensor strength and weight-bearing ankle dorsiflexion.
Findings: Reduced hip adduction (0.82°, P = 0.01), knee internal rotation (0.46°, P = 0.03), and decreased gluteus medius peak amplitude (0.9 mV, P = 0.043) were observed after ground contact in the ‘with orthoses’ condition. With the addition of orthoses, a more pronated foot posture correlated with earlier vastus medialis oblique onset (r = − 0.51, P = 0.02) whilst higher Kujala scores correlated with earlier gluteus medius onset (r = 0.52, P = 0.02).
Interpretation: Although small in magnitude, reductions in hip adduction, knee internal rotation and gluteus medius amplitude observed immediately following orthoses application during a task that commonly aggravates symptoms, offer a potential mechanism for their effectiveness in patellofemoral pain management. Given the potential for cumulative effects of weight bearing repetitions completed with a foot orthoses, for example during repeated stair ascent, the differences are likely to be clinically meaningful.
Outcome Predictors for Conservative Patellofemoral Pain Management: A Systematic Review and Meta-Analysis
Objective: Our aim was to systematically review the literature that identifies outcome predictors of specific conservative interventions in the management of PFP, including quality of the current evidence, to guide clinical practice and future studies investigating outcome predictors within this population.
Data Sources: The AMED, CINAHL, EMBASE, MEDLINE and Web of Science databases were searched from inception to April 2013.
Randomized controlled trials (RCTs) and cohort studies.
Study Appraisal and Synthesis Methods
Following initial searching, all potential papers were assessed by two independent reviewers for inclusion using a checklist developed from the inclusion criteria. Cited, and citing, references were also searched in Google Scholar, but unpublished work was not sought. Methodological quality was assessed using a previously designed quality assessment scale. Definitions for levels of evidence were guided by recommendations made by van Tulder et al.
Results: Fifteen low-quality (LQ) cohort studies were included. No RCTs were found. This systematic review identified the evaluation of 205 conservative management outcome predictor variables. Of this large number of variables that have been assessed, 19 (9 %) were found to significantly predict a successful outcome. Where two or more outcome predictors and success determinants were consistent between studies, data were pooled. Within these studies, the low number of participants per output variable, and absence of controls, is likely to compromise the validity of the predictor’s accuracy. Very limited evidence identified higher functional index questionnaire scores (mean 0.82, 95 % confidence interval [CI] 0.18–1.46), greater forefoot valgus (mean 0.67, 95 % CI 0.05–1.28) and greater rearfoot eversion magnitude peak (mean −0.93, 95 % CI −1.84 to −0.01) to significantly predict improved outcomes with orthoses interventions. Shorter symptom duration (p = 0.019), lower frequency of pain (p = 0.012), younger age, faster vastus medialis oblique reflex response time (p = 0.026), negative patella apprehension, absence of chondromalacia patella, tibial tubercle deviation of <14.6 mm and greater total quadriceps cross-sectional area on magnetic resonance imaging (p = 0.01), and reduced eccentric average quadriceps peak torque (p = 0.015) significantly predicted exercise intervention success following multivariate statistical analysis. Limited evidence identified increased Q-angle (mean 0.38, 95 % CI 0.05–0.72) and very limited evidence identified greater usual pain (mean 0.43, 95 % CI 0.01–0.85) to predict taping intervention success.
Conclusions: This systematic review provides a comprehensive summary of current derivation level studies identifying indicators of prediction for conservative PFP management. The overall strength of evidence was low. With appropriate caution, clinicians should consider taping for those with greater usual pain, orthoses for older individuals and exercise for younger individuals, and orthoses intervention for patients with greater forefoot valgus and rearfoot eversion magnitude peak. RCTs with evaluation of outcome prediction as a primary aim are clearly warranted to provide clinicians with robust evidence and facilitate evidence-informed, tailored intervention to this heterogeneous patient population.
The effect of anti-pronation foot orthoses on hip and knee kinematics and muscle activity during a functional step-up task in healthy individuals: A laboratory study
Patellar taping for patellofemoral pain: a systematic review and meta-analysis to evaluate clinical outcomes and biomechanical mechanisms
Methods: The MEDLINE, CINAHL, SPORTSDiscus, Web of Science and Google Scholar databases were searched in January 2013 for studies evaluating the effects of patellar taping on pain and lower-limb biomechanics in individuals with PFP. Three independent reviewers assessed each paper for inclusion and two assessed for quality. Means and SDs were extracted from each included study to allow effect size calculations.
Results: Twenty studies were identified. There is moderate evidence that (1) tailored (customised to the patient to control lateral tilt, glide and spin) and untailored patellar taping provides immediate pain reduction of large and small effect, respectively and (2) tailored patellar taping promotes earlier onset of vastus medialis oblique (VMO) contraction (relative to vastus lateralis contraction). There is limited evidence that (1) tailored patellar taping combined with exercise provides superior pain reduction compared to exercise alone at 4 weeks, (2) untailored patellar taping added to exercise at 3–12 months has no benefit and (3) tailored patellar taping promotes increased internal knee extension moments.
Conclusions: Tailoring patellar taping application (ie, to control lateral tilt, glide and spin) to optimise pain reduction is important for efficacy. Evaluation of tailored patellar taping beyond the immediate term is limited and should be a research priority. Possible mechanisms behind patellar taping efficacy include earlier VMO onset and improved knee function capacity (ie, ability to tolerate greater internal knee extension moments).