Impairments in peroneal muscle size and activation in individuals with patellofemoral pain in weight-bearing position.

BACKGROUND: Patellofemoral pain (PFP) is characterized by chronic pain in the anterior aspect of the knee during loading activities. Many studies investigating muscle morphology changes for individuals with PFP focus on the proximal joints, however, few studies have investigated muscles of the foot and ankle complex. This study aimed to explore the differences in peroneal muscle size and activation between individuals with PFP and healthy controls using ultrasound imaging in weight-bearing. METHODS: A case-control study in a university lab setting was conducted. Thirty individuals with PFP (age: 20.23 ± 3.30 years, mass: 74.70 ± 27.63 kgs, height: 161.32 ± 11.72 cm) and 30 healthy individuals (age: 20.33 ± 3.37 years, mass: 64.02 ± 11.00 kgs, height: 169.31 ± 9.30 cm) participated. Cross-sectional area (CSA) images of the peroneal muscles were taken in non-weight bearing and weight-bearing positions. The functional activation ratio from lying to single-leg standing (SLS) was calculated. RESULTS: There was a statistically significant (p = 0.041) group (PFP, healthy) by position (non-weight-bearing, weight-bearing) interaction for the peroneal muscle CSA with a Cohen's d effect size of 0.2 in non-weight-bearing position and 0.7 in weight-bearing position. The functional activation ratio for the healthy group was significantly more (p = 0.01) than the PFP group. CONCLUSION: Peroneal muscles were found to be smaller in size in those with PFP compared to the healthy subjects in the weight-bearing SLS position. This study found that those with PFP have lower activation of peroneal muscles in functional position.

Dose atrophy of vastus medialis obliquus and vastus lateralis exist in patients with patellofemoral pain syndrome.

BACKGROUND: Whether vastus medialis obliquus atrophy exists in patients with patellofemoral pain syndrome and whether the amount of atrophy differs between the vastus medialis obliquus and vastus lateralis muscles remain unknown. MATERIALS: From June 2016 to March 2019, 61 patients with patellofemoral pain syndrome were retrospectively included in the study group, and an age-, sex-, and body mass index-matched cohort of 61 patients with normal knees was randomly selected as the control group. All enrolled subjects had undergone CT scans in the supine position. The cross-sectional areas of the vastus medialis obliquus and the vastus lateralis muscle in the sections 0, 5, 10, 15, and 20 mm above the upper pole of the patella were measured, and the vastus medialis obliquus/vastus lateralis muscle area ratio was evaluated. RESULTS: In the study group, the vastus medialis obliquus areas and the vastus lateralis muscle areas in the sections that were 0, 5, 10, 15, and 20 mm above the upper pole of the patella were significantly smaller than the respective areas in the control group (P < 0.05). The vastus medialis obliquus/vastus lateralis muscle area ratio was significantly smaller at the upper pole of the patella (the section 0 mm above the upper pole of the patella) than the corresponding ratio in the control group (P < 0.05). No significant difference was noted between the two groups in the sections 5, 10, 15, and 20 mm above the upper pole of the patella (P > 0.05). CONCLUSION: In patients with patellofemoral pain syndrome, vastus medialis obliquus and vastus lateralis muscle atrophy existed in sections 0-20 mm above the upper pole of the patella, compared with normal controls, and atrophy of the vastus medialis obliquus was more evident than that of the vastus lateralis muscle at the upper pole of the patella. These findings support the rationale for the use of general quadriceps exercise combined with vastus medialis obliquus strengthening exercise as part of the rehabilitation programme for the patients with patellofemoral pain syndrome.

Selective Atrophy of the Vastus Medialis: Does It Exist in Women With Nontraumatic Patellofemoral Pain?

BACKGROUND: A commonly cited theory related to the pathomechanics of patellofemoral pain (PFP) states that atrophy of the vastus medialis (VM) muscle leads to lateral tracking of the patella. However, isolated atrophy of the VM or atrophy of the quadriceps muscle group as a whole, has not been consistently reported in this population. PURPOSE: To compare individual and total quadriceps muscle volumes between women with nontraumatic PFP and women without PFP as measured on magnetic resonance imaging scans. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 52 women with nontraumatic PFP and 64 women without PFP between the ages of 18 and 45 years participated. Magnetic resonance imaging scans of the thigh were obtained from the anterior inferior iliac spine to the tibial plateau. Individual quadriceps muscle cross-sectional area measurements were obtained from each image, and muscle volumes for the VM, vastus lateralis, vastus intermedius, and rectus femoris were calculated. Muscle volume measurements were expressed in absolute values and normalized to body mass. Separate 2-way mixed-factorial analysis of variance (group × muscle) were used to compare absolute and normalized individual muscle volumes between groups. Independent t tests were used to compare absolute and normalized total quadriceps volumes between groups. RESULTS: There was no difference in absolute and normalized individual muscle volumes between individuals with and those without PFP. Additionally, absolute and normalized total muscle volumes did not differ between groups. CONCLUSION: Our findings do not support the concept of preferential atrophy of the VM or generalized quadriceps atrophy in women with nontraumatic PFP.

The effects of McConnell patellofemoral joint and tibial internal rotation limitation taping techniques in people with Patellofemoral pain syndrome.

BACKGROUND: Taping is frequently used as part of the multi-modal management for patellofemoral pain syndrome (PFPS). McConnell Patellofemoral Joint Taping (PFJT) and Tibial Internal Rotation Limitation Taping (TIRLT) are proposed to be useful adjuncts to the management of PFPS. However, it is unclear if TIRLT offers similar benefits to PFJT, and its effect on pain and lower limb kinematics have not been investigated previously. RESEARCH QUESTION: What are the effects of TIRLT, PFJT and no taping on perceived pain and lower limb kinematics during a lunge and single leg squat (SLS) in people with PFPS? METHODS: This cross-sectional study compared the effects of TIRLT, PFJT and no taping, on knee pain and lower limb kinematics during two pain-provoking movements in people with PFPS. Participants with PFPS (n = 23) performed a lunge and SLS under three randomised conditions: TIRLT, PFJT and no taping. The Codamotion system captured and analysed lower limb kinematic data in the sagittal, transverse and coronal planes. Peak knee pain intensity during the movement was assessed using the Numerical Rating Scale (NRS). RESULTS: Participants reported significantly less pain with the TIRLT and PFJT techniques compared with no tape during the lunge (p = 0.005 and p = 0.011, respectively) and SLS (p= 0.002 and p = 0.001, respectively). There was no evidence of altered lower limb kinematics accompanying pain reductions with either taping technique. SIGNIFICANCE: Both forms of taping may be useful adjuncts as the short-term benefit of pain relief may enable participation in more active forms of rehabilitation.

Prevalência e fatores associados à Síndrome da dor Patelofemoral em escolares de Natal/RN / Prevalence and factors associated with Patellofemoral pain syndrome in schoolchildren from Natal/RN

Objetivo: Estimar a prevalência e analisar os fatores relacionados à Síndrome da dor Patelofemoral (SDPF) em escolares de ambos os sexos, entre 10 e 18 anos, matriculados no ensino público fundamental e médio do município de Natal/RN. Métodos: A pesquisa teve caráter exploratório descritivo, transversal e quantitativo realizada no município de Natal-RN. Foi avaliada a presença da SDPF, o nível de atividade física, a qualidade do movimento, o índice de massa corporal (IMC), o tipo de pé, o nível de dor e o comprometimento funcional. As prevalências foram calculadas a partir do desenho complexo de amostragem com a inclusão dos pesos e efeitos de cluster. Para a análise de associação, foram calculadas as Razões de Prevalência (RP) ajustadas e os respectivos intervalos de confiança (95%) do desfecho em relação às variáveis independentes e adotado um nível de significância de 5%. Resultados: Participaram da pesquisa 144 escolares, 51,4 % (IC:41,6 ­ 61,1) da amostra tem o sexo masculino. Foi observada uma prevalência de 29,7% (IC:21,5 ­ 39,4) da SDPF. No modelo ajustado a SDPF foi mais prevalente no sexo feminino (p = 0,02) (RP: 1,82 IC: 1,0 ­ 3,0), nos indivíduos ativos (p = 0,02) (RP:2,3 IC: 1,13 ­ 4,9), nos jovens abaixo do peso (p = 0,03) (RP: 1,9 IC:1,0 ­ 3,6). Quando avaliados por sexo, os homens apresentaram uma associação positiva entre a pobre qualidade do movimento do membro direito (p: 0,01) (RP: 6,0 IC: 1,3 ­ 26) e o desfecho e o sexo feminino obteve uma associação com a presença do valgo dinâmico do joelho esquerdo (p: 0,03) (RP: 2,4 IC:1,0 ­ 5,8). Conclusões: A prevalência da SDPF foi maior no sexo feminino, em jovens ativos, e com baixo peso, ao mesmo tempo, a pobre qualidade do movimento foi associada aos jovens homens com a síndrome e a presença do valgo dinâmico do joelho nas jovens (AU).

Objective: To estimate the prevalence and analysis the factors related to patellofemoral pain syndrome (PFPS) in schoolchildren of both genders, between 10 and 18 years old, enrolled in public elementary and high school in the city of Natal / RN. Methods: The research had an exploratory, descriptive, transversal, and quantitative character carried out in the city of NatalRN. The presence of PFPS was evaluated, as well as the level of physical activity through IPAQ, the quality of movement, body mass index, navicular drop test, pain level and Kujala questionnaire. The prevalence was calculated from the complex sampling design with the inclusion of weights and cluster effects. For an association analysis, adjusted Prevalence Ratios (PR) and the confidence intervals (95%) of the outcome in relation to the independent variables were calculated and a significance level of 5% was adopted. Results: 144 students participated in the research, 51.4% (CI: 41.6 - 61.1) of the sample is male. A prevalence of 29.7% (CI: 21.5 - 39.4) of PFPS was observed. In the adapted model, the PFPS was more prevalent in females (p = 0.02) (PR: 1.82 CI: 1.0 - 3.0), in physical active (p = 0.02) (PR: 2, 3 CI: 1.13 - 4.9), in underweight youth (p = 0.03) (PR: 1.9 CI: 1.0 - 3.6). When obtained by sex, men associated a positive association between poor quality of movement of the right limb (p: 0.01) (PR: 6.0 CI: 1.3 - 26) and the outcome and the female sex obtained an association with the presence of the dynamic valgus of the left knee (p: 0.03) (PR: 2.4 CI: 1.0 - 5.8). Conclusions: The prevalence of PFPS was higher in females, in active young people, and with low weight, at the same time, the poor quality of movement associated with young male people with the syndrome and the presence of dynamic knee valgus in young women (AU).

Patellofemoral cartilage stresses are most sensitive to variations in vastus medialis muscle forces.

The purpose of this study was to evaluate the effects of variations in quadriceps muscle forces on patellofemoral stress. We created subject-specific finite element models for 21 individuals with chronic patellofemoral pain and 16 pain-free control subjects. We extracted three-dimensional geometries from high resolution magnetic resonance images and registered the geometries to magnetic resonance images from an upright weight bearing squat with the knees flexed at 60°. We estimated quadriceps muscle forces corresponding to 60° knee flexion during a stair climb task from motion analysis and electromyography-driven musculoskeletal modelling. We applied the quadriceps muscle forces to our finite element models and evaluated patellofemoral cartilage stress. We quantified cartilage stress using an energy-based effective stress, a scalar quantity representing the local stress intensity in the tissue. We used probabilistic methods to evaluate the effects of variations in quadriceps muscle forces from five trials of the stair climb task for each subject. Patellofemoral effective stress was most sensitive to variations in forces in the two branches of the vastus medialis muscle. Femur cartilage effective stress was most sensitive to variations in vastus medialis forces in 29/37 (78%) subjects, and patella cartilage effective stress was most sensitive to variations in vastus medialis forces in 21/37 (57%) subjects. Femur cartilage effective stress was more sensitive to variations in vastus medialis longus forces in subjects classified as maltrackers compared to normal tracking subjects (p = 0.006). This study provides new evidence of the importance of the vastus medialis muscle in the treatment of patellofemoral pain.

Increased Patellar Volume/Width and Decreased Femoral Trochlear Width Are Associated With Adolescent Patellofemoral Pain.

BACKGROUND: Patellofemoral pain is one of the most common forms of knee arthralgia in adolescent females. Unlike in adults, in whom the etiology of patellofemoral pain is considered to be multifactorial (eg, altered bone shape and musculoskeletal dynamics), the etiology of adolescent patellofemoral pain has been historically attributed to overuse. Although it is highly plausible that adolescent patellofemoral pain results from excessive maltracking, as suggested by recent research, an increase in patellar, relative to femoral, size could also contribute to patellofemoral pain through altered cartilage stresses/strains, resulting in overloading of the subchondral bone. Because the role of bone morphology in the genesis of patellofemoral pain in adolescent females remains largely unknown, research is needed in this area to improve our understanding of patellofemoral pain and advance diagnosis/treatment. QUESTIONS/PURPOSES: (1) Are patellar volume and width increased, and femoral trochlear width decreased, in female adolescents with patellofemoral pain compared with asymptomatic females? (2) Are measures of patellofemoral size correlated with patellofemoral tracking? METHODS: Twenty adolescent females with patellofemoral pain (age, 13.7 ± 1.3 years) and 20 asymptomatic female control participants (age, 13.6 ± 1.3 years) were enrolled in this case-control institutional review board-approved study. This study focused on a strict definition of patellofemoral pain, peripatellar pain in the absence of other structural pathologic conditions (eg, tendinitis, ligament injury, Osgood-Schlatter disease) or a history of dislocations/trauma. Control participants with no history of patellofemoral pain or other lower extremity pathology were matched for age (within 6 months) and body mass index (within 5 kg/m). Participants self-referred and were recruited through clinicaltrails.gov, printed advertisements, and word of mouth. Three-dimensional (3-D), static, T1-weighted, gradient recalled echo MR images were acquired, from which 3-D patellofemoral models were created. Patellar volume and width, patellar-to-femoral volume and width ratios, and femoral trochlear width were compared across cohorts. In addition, 3-D patellofemoral tracking was quantified from dynamic MR images captured during cyclical flexion-extension volitional movements of the lower extremity. The size measures and ratios were correlated to patellofemoral tracking. RESULTS: Compared with control participants, the cohort with patellofemoral pain had greater patellar volume (13,792 ± 2256 versus 11,930 ± 1902 mm; 95% confidence interval [CI], 1336 mm; p = 0.004; d = 0.89) and width (38.4 ± 3.0 versus 36.5 ± 2.7 mm; 95% CI, 1.8 mm; p = 0.021; d = 0.67). The femoral trochlear width was smaller (32.0 ± 1.8 versus 32.9 ± 1.8 mm; p = 0.043, d = 0.54). The patellar-to-femoral volume ratio and the patellar-to-trochlear width ratio were greater in adolescents with patellofemoral pain (0.15 ± 0.02 versus 0.13 ± 0.01, p = 0.006, d = 0.83 and 1.20 ± 0.09 versus 1.11 ± 0.09, p = 0.001, d = 1.02). No correlations were found between patellar size and patellofemoral tracking (r < 0.375, p > 0.103). CONCLUSIONS: In adolescent females with patellofemoral pain, the increased patellar volume/width and patellar-to-trochlear width ratio, along with the decreased femoral trochlear width, may initiate a pathway to pain through improper engagement of the patella within the femoral trochlea. Specifically, the mean differences between cohorts in patellar and femoral trochlear width (1.9 mm and 0.9 mm) are 58% and 37% of the mean patellar and femoral cartilage thickness in females, respectively, as reported in the literature. Further studies are needed to fully elucidate the mechanism of pain. LEVEL OF EVIDENCE: Level III, prognostic study.

Popping the cap: the constellation of MRI findings in patellofemoral syndrome.

Patellofemoral syndrome (PFS) is a common etiology of anterior knee pain, particularly among young female athletes. Despite recent advancements in the resolution of MRI, there still remains a paucity of literature that has investigated the MRI findings associated with PFS. This pictorial essay will describe our institution's experience with cases of PFS and review what we believe to be a constellation of findings associated with this diagnostic entity. This review will also describe common pitfalls encountered during the diagnosis of PFS.

Nível de ativação muscular do vasto medial em diferentes exercícios fisioterapêuticos / Activation level of vastus medialis muscle in different rehabilitation exercises

A Síndrome da Dor Femoropatelar (SDFP) tem como uma das causas a lateralização excessiva da patela, que ocorre frequentemente pelo enfraquecimento do músculo Vasto Medial (VM). Dessa forma, na prevenção e reabilitação da SDFP, o fortalecimento de VM é imprescindível. Objetivo: Comparar o nível de ativação do VM em quatro diferentes exercícios utilizados na prevenção e na reabilitação da SDFP compreendendo isometria de extensão de joelhos a 30° e 60° e isometria no agachamento a 60° associado ou não a adução de quadril. Métodos: A amostra foi de 14 sujeitos saudáveis sedentários, com idade entre 20 e 40 anos. O sinal EMG do músculo VM foi coletado durante Contração Isométrica Voluntária Máxima (CIVM) com duração de cinco segundos para cada exercício. Do sinal EMG captado foi recortado um período de três segundos e a partir disso foram obtidos os valores Root Mean Square (RMS) para cada exercício. Resultados: Demonstram que houve ativação do VM significativamente maior nos exercícios de extensão quando comparados com os exercícios de agachamento. Porém, não houve diferença significativa entre os dois exercícios de extensão, assim como entre os exercícios de agachamento. Conclusão: Os melhores exercícios para maximizar a ativação do VM são os exercícios isométricos de extensão do joelho, independente do ângulo avaliado, pois apresentam maior nível de ativação do VM, imprescindível para a prevenção e reabilitação da SDFP

Excessive lateralization, which often occurs by the weakening of Vastus Medialis (VM) muscle of the patella, is one of the causes of Patellofemoral Pain Syndrome (PFPS) For prevention and rehabilitation of PFPS, the VM strength is essential. Objective: The aim of the study was to compare the VM activation level in four different exercises used in the prevention and rehabilitation of PFPS that are isometric knee extension at 30° and 60° and isometric squat at 60° with or without hip adduction. Methods: A sample of 14 sedentary healthy subjects, aged between 20 and 40 years was included. The EMG signal of VM muscle was collected during Maximal Voluntary Isometric Contraction with duration of five seconds for each exercise. From the captured EMG signal, a period of three seconds was cut and thereafter the Root Mean Square value for each exercise was obtained. Results: The results showed that there was significantly greater activation in VM extension exercises compared to squat exercises. However, there was no significant difference between the two extension exercises, as well as between squat exercises. Conclusion: It can be concluded that the best exercises to maximize the activation of the VM are the isometric knee extension, regardless of the rated angle, since they have greater VM activation level, essential for the prevention and rehabilitation of PFPS

No Difference on Quantitative Magnetic Resonance Imaging in Patellofemoral Cartilage Composition Between Patients With Patellofemoral Pain and Healthy Controls.

BACKGROUND: Retropatellar cartilage damage has been suggested as an etiological factor for patellofemoral pain (PFP), a common knee condition among young and physically active individuals. To date, there is no conclusive evidence for an association between cartilage defects and PFP. Nowadays, advanced quantitative magnetic resonance imaging (MRI) techniques enable estimation of cartilage composition. PURPOSE: To investigate differences in patellofemoral cartilage composition between patients with PFP and healthy control subjects using quantitative MRI. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients with PFP and healthy control subjects underwent 3.0-T MRI including delayed gadolinium-enhanced MRI of cartilage and T1ρ and T2 mapping. Differences in relaxation times of patellofemoral cartilage were compared between groups by linear regression analyses, adjusted for age, body mass index, sex, sports participation, and time of image acquisition. RESULTS: This case-control study included 64 patients and 70 controls. The mean (±SD) age was 23.2 ± 6.4 years and the mean body mass index was 22.9 ± 3.4 kg/m(2); 56.7% were female. For delayed gadolinium-enhanced MRI of cartilage, the mean T1GD relaxation times of patellar (657.8 vs 669.4 ms) and femoral cartilage (661.6 vs 659.8 ms) did not significantly differ between patients and controls. In addition, no significant difference was found in mean T1ρ relaxation times of patellar (46.9 vs 46.0 ms) and femoral cartilage (50.8 vs 50.2 ms) and mean T2 relaxation times of patellar (33.2 vs 32.9 ms) and femoral cartilage (36.7 vs 36.6 ms) between patients and controls. Analysis of prespecified medial and lateral subregions within the patellofemoral cartilage also revealed no significant differences. CONCLUSION: There was no difference in composition of the patellofemoral cartilage, estimated with multiple quantitative MRI techniques, between patients with PFP and healthy control subjects. However, clinically relevant differences could not be ruled out for T1ρ in the adolescent population. Retropatellar cartilage damage has long been hypothesized as an important factor in the pathogenesis of PFP, but study findings suggest that diminished patellofemoral cartilage composition is not associated with PFP.

Which patellofemoral joint imaging features are associated with patellofemoral pain? Systematic review and meta-analysis.

OBJECTIVES: To review the association between patellofemoral joint (PFJ) imaging features and patellofemoral pain (PFP). DESIGN: A systematic review of the literature from AMED, CiNAHL, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PEDro, EMBASE and SPORTDiscus was undertaken from their inception to September 2014. Studies were eligible if they used magnetic resonance imaging (MRI), computed tomography (CT), ultrasound (US) or X-ray (XR) to compare PFJ features between a PFP group and an asymptomatic control group in people <45 years of age. A pooled meta-analysis was conducted and data was interpreted using a best evidence synthesis. RESULTS: Forty studies (all moderate to high quality) describing 1043 people with PFP and 839 controls were included. Two features were deemed to have a large standardised mean difference (SMD) based on meta-analysis: an increased MRI bisect offset at 0° knee flexion under load (0.99; 95% CI: 0.49, 1.49) and an increased CT congruence angle at 15° knee flexion, both under load (1.40 95% CI: 0.04, 2.76) and without load (1.24; 95% CI: 0.37, 2.12). A medium SMD was identified for MRI patella tilt and patellofemoral contact area. Limited evidence was found to support the association of other imaging features with PFP. A sensitivity analysis showed an increase in the SMD for patella bisect offset at 0° knee flexion (1.91; 95% CI: 1.31, 2.52) and patella tilt at 0° knee flexion (0.99; 95% CI: 0.47, 1.52) under full weight bearing. CONCLUSION: Certain PFJ imaging features were associated with PFP. Future interventional strategies may be targeted at these features. PROSPERO REGISTRATION NUMBER: CRD 42014009503.

Patellofemoral Pain in Adolescence and Adulthood: Same Same, but Different?

The mainstay of patellofemoral pain (PFP) treatment is exercise therapy, often in combination with adjunct treatments such as patient education, orthoses, patella taping and stretching, making the intervention multimodal in nature. The vast majority of randomised controlled trials among patients with PFP have investigated the effect of treatment among adults (>18 years of age). So, while systematic reviews and meta-analyses provide evidence-based recommendations for treating PFP, these recommendations are largely based upon the trials in adults. In the present article, we have summarised the findings on the efficacy of multimodal treatment (predominantly exercise) from the three largest trials concerning patients with PFP, focusing on the long-term success-rate 1 year after receiving multimodal treatment, and with a particular focus on the success rate across the different age groups, including both adolescents, young adults and adults. The results of this paper show that there appears to be a difference in the success rate between adolescents and adults, despite providing similar exercise treatment and having similar exercise compliance. While PFP may present in a similar fashion in adolescence and adults, it may not be the same underlying condition or stage, and different treatments may be required. Collectively, this highlights the importance of increasing our understanding of the underlying pathology, pain mechanisms and why treatment may-or may not-work in adolescents and adults with PFP.

Atrophy of the Quadriceps Is Not Isolated to the Vastus Medialis Oblique in Individuals With Patellofemoral Pain.

STUDY DESIGN: Cross-sectional. Objectives To determine if quadriceps atrophy was present in people with patellofemoral pain (PFP), and whether the vastus medialis oblique (VMO) was selectively involved. BACKGROUND: Despite the lack of research investigating individual quadriceps muscle size in individuals with PFP, it has been suggested that selective atrophy of the VMO relative to the vastus lateralis could be associated with PFP. METHODS: The quadriceps muscle sizes of 35 participants with PFP (22 with unilateral and 13 with bilateral symptoms) and 35 asymptomatic control participants matched for age and sex were measured using real-time ultrasound. The thicknesses of the VMO, vastus lateralis, vastus medialis, rectus femoris, and vastus intermedius were measured. Paired-samples t tests were used to compare muscle thickness between limbs in those with unilateral PFP, and independent t tests were used to compare muscle thickness between groups with and without PFP. Results In those with unilateral PFP, the thickness of all portions of the quadriceps muscle was statistically smaller in the symptomatic compared to the asymptomatic limb: VMO (P = .038), vastus medialis (P<.001), vastus lateralis (P = .005), vastus intermedius (P = .013), and rectus femoris (P = .045). No difference was found in thickness of any of the portions of the quadriceps on the affected side of people with PFP compared to asymptomatic controls: VMO (P = .148), vastus medialis (P = .474), vastus lateralis (P = .122), vastus intermedius (P = .466), and rectus femoris (P = .508). CONCLUSION: Atrophy of all portions of the quadriceps muscles is present in the affected limb of people with unilateral PFP. There was no atrophy of the quadriceps in individuals with PFP compared to those without pathology. Selective atrophy of the VMO relative to the vastus lateralis was not identified in people with PFP.

Can ultrasound measurements of muscle thickness be used to measure the size of individual quadriceps muscles in people with patellofemoral pain?

OBJECTIVES: Selective atrophy of vastus medialis oblique (VMO) may be present in patellofemoral pain (PFP). This study investigated the validity of real-time ultrasound in measuring the thickness of each quadriceps muscle. DESIGN: Cross sectional-Validity. SETTING: University laboratory. PARTICIPANTS: 10 limbs, 5 people with unilateral PFP. MAIN OUTCOME MEASURES: The thickness of VMO, vastus lateralis (VL), vastus intermedius (VI), rectus femoris (RF), and vastus medialis (VM) measured with ultrasound were compared to magnetic resonance imaging (MRI) muscle thickness measurements, using Pearson's (r), and compared to MRI muscle cross-sectional area (CSA) measurements, using Spearman's correlation coefficient (rho). RESULTS: There was a good correlation between ultrasound and MRI measures of the thickness of each superficial quadriceps muscle VMO (r = 0.86), VM (r = 0.86), VL (r = 0.94), RF (r = 0.86), and a poor for VI (r = 0.37). Ultrasound measures had a good correlation to MRI muscle CSA measures for VL (rho = 0.83) and RF (rho = 0.88), moderate for VM (rho = 0.73), and poor for VMO (rho = 0.20), and VI (rho = 0.310). CONCLUSION: Real-time ultrasound muscle thickness measurements are correlated to MRI measured thickness of superficial quadriceps muscles (VMO, VL, VL, and RF) in PFP.

MR imaging of extrasynovial inflammation and impingement about the knee.

The knee has unique anatomy regarding the relationship between the synovial and capsular layers, with interposed fat pads at certain locations. The extrasynovial impingement and inflammation syndromes about the knee are underdiagnosed and should be included in the differential diagnosis of anterior knee pain. MR imaging is the best imaging modality for evaluation of the anatomy and disorders of these extrasynovial compartments.

In vivo measurements of patellar tracking and finite helical axis using a static magnetic resonance based methodology.

Patellofemoral (PF) maltracking is a critical factor predisposing to PF pain syndrome. Many novel techniques of measuring patellar tracking remain research tools. This study aimed to develop a method to measure the in vivo patellar tracking and finite helical axis (FHA) by using a static magnetic resonance (MR) based methodology. The geometrical models of PF joint at 0°, 45°, 60°, 90°, and 120° of knee flexion were developed from MR images. The approximate patellar tracking was derived from the discrete PF models with a spline interpolation algorithm. The patellar tracking was validated with the previous in vitro and in vivo experiments. The patellar FHA throughout knee flexion was calculated. In the present case, the FHA drew an "L-shaped" curve in the sagittal section. This methodology could advance the examination of PF kinematics in clinics, and may also provide preliminary knowledge on patellar FHA study.

Abordagens fisioterapêuticas na síndrome da dor patelofemoral: revisão de literatura / Physiotherapeutic approaches in patellofemoral pain syndrome: literature review

Introdução: Síndrome da dor patelofemoral (SDPF) é um termo comumente usado para descrever dor anterior de joelho, com gênese devido a diversos fatores, sendo agravada em movimentos de subir e descer escadas, permanecer sentado por muito tempo. Objetivo: Revisar na literatura as abordagens fisioterapêuticas utilizadas no tratamento da síndrome da dor femoropatelar, ressaltando os mais recentes protocolos de tratamento, analisar os efeitos dessas técnicas à patologia, avaliar e discutir a viabilidade desses tratamentos. Métodos: Realizou-se uma busca na literatura, nas bases de dados Lilacs, Medline e PubMed, utilizando palavras-chave dos Descritores em Ciências da Saúde (DECS), nos idiomas português, inglês e espanhol. Para a seleção dos artigos, foi usada a escala metodológica de Jadad. Resultados: Foram selecionados 12 estudos, incluindo 930 pacientes em diversos protocolos de tratamento da patologia estudada. Conclusão: Identificaram-se estudos com novos tratamentos para dor femoropatelar, aumentando, assim, a gama de protocolos para essa doença.

Introduction: Patellofemoral Pain Syndrome is a term commonly used to describe anterior knee pain – arising due to several factors – and is aggravated on moving up and down stairs or sitting for long period of time. Objective: To review in the literature physiotherapy resources used in the treatment of patellofemoral pain syndrome, highlighting the newest treatment protocols, analyzing the effect of these resources to pathology, evaluate and discuss the feasibility of such treatments. Methods: A literature search was performed in Lilacs, Medline and PubMed databases using MeSH keywords – Health Sciences Descriptors in Portuguese, English and Spanish languages. For the selection of articles was used methodological Jadad scale. Results: Twelve studies were selected including, 930 patients undergoing various treatment protocols for the pathology under study. Conclusion: Studies of new treatments for patellofemoral pain were identified, thus increasing the range of the protocols for this disease.

The association of patellofemoral joint morphology with chondromalacia patella: a quantitative MRI analysis.

The relationship of patellofemoral congruency with chondromalacia patellae (CP) was retrospectively evaluated. Lateral patellar tilt angle (LPTA), sulcus angle (SA), trochlear depth (TD), and patella angle (PA) were measured at 301 knee magnetic resonance images and compared between groups with and without CP. In the CP group, LPTA and TD were significantly low (P<.01), SA was high (P<.01), while PA showed no difference (P>.05). The parameters were also compared between groups with mild and severe CP, and no significant difference was found (P>.05). Our results demonstrate that patellar tilt and trochlear dysplasia are related to the presence but not the degree of CP.

Patellofemoral friction syndrome: magnetic resonance imaging correlation of morphologic and T2 cartilage imaging.

OBJECTIVE: This study aimed to investigate whether patellofemoral T2 cartilage changes are associated with lateral patellofemoral friction syndrome (PFS), as indicated by an edema-like signal within the superolateral infrapatellar (Hoffa) fat pad. METHODS: In this institutional review board-approved retrospective study of 510 consecutive patients, 49 patients with 50 knee magnetic resonance imaging examinations demonstrating normal or low-grade patellofemoral cartilage abnormalities (whole-organ magnetic resonance imaging score [WORMS] score, ≤2) were included. Twenty-two examinations with PFS (cases) were compared with an age- and sex-matched cohort of 28 examinations without PFS (controls). A 3-T magnetic resonance imaging was performed with multi-echo, spin-echo T2 mapping. Two readers measured in consensus malalignment parameters, including patellar height index, tibial tuberosity to trochlear groove distance, and sulcus angle. Bulk T2 cartilage values in the lateral and medial patellofemoral compartment, central weight-bearing medial and lateral femoral condyles were measured independently. Interobserver agreement was quantified using concordance correlation coefficients. Demographics, anatomic measurements, whole-organ magnetic resonance imaging scores, and cartilage T2 values were compared between cases and controls using Fisher exact test, Wilcoxon rank sum test, and mixed-effects models. RESULTS: Cases demonstrated higher patellar height index (P = 0.002) and tibial tuberosity to trochlear groove distance (P = 0.02). Interobserver agreement for T2 values was good overall (concordance correlation coefficient range, 0.65-0.93). Cases demonstrated higher medial facet patellar bulk T2 (38.1 [7.5] ms) versus controls (33.6 [7.3] ms) (P = 0.02); otherwise, there were no significant differences in regional T2 values. CONCLUSIONS: T2 mapping in patients with PFS demonstrates increased cartilage T2 in the medial patellar facet, possibly reflecting collagen alteration from early chondromalacia (softening) or increased water content related to altered contact pressures.

Does quadriceps atrophy exist in individuals with patellofemoral pain? A systematic literature review with meta-analysis.

STUDY DESIGN: Systematic literature review. OBJECTIVES: To investigate whether quadriceps atrophy is present in the affected limb of individuals with patellofemoral pain (PFP). BACKGROUND: PFP is a common condition. Atrophy of the quadriceps femoris, in particular the vastus medialis obliquus, is often assumed to be present by clinicians, and its resolution may underpin the reported effectiveness of quadriceps strengthening intervention in PFP rehabilitation. METHODS: A systematic search of the literature was conducted to identify studies that measured the size of the quadriceps in individuals with PFP. Meta-analyses were performed to determine whether quadriceps size in limbs with PFP differed from that in comparison limbs. Separate meta-analyses were performed for quadriceps size measured as girth and quadriceps size measured with imaging (thickness, cross-sectional area, and volume). RESULTS: Ten studies were included in this review. The meta-analysis of girth measurements (3 studies) found no atrophy in limbs with PFP (P = .638). The meta-analyses for imaging techniques (thickness, cross-sectional area, or volume measurements) showed atrophy in the limb with PFP compared to both the asymptomatic limb (3 studies) (P = .036) and limbs from a comparison group (3 studies) (P = .001). The single study that compared the vastus medialis obliquus and vastus lateralis in individuals with PFP found atrophy of both the vastus medialis obliquus and vastus lateralis but no significant difference in the amount of atrophy between them (P = .179). CONCLUSION: Quadriceps muscle atrophy was shown to be present in PFP when analyzed by imaging, but not by girth measures. Insufficient data were available to determine if there was greater atrophy of the vastus medialis obliquus than the vastus lateralis. These findings support the rationale for use of quadriceps strengthening as part of a rehabilitation program for PFP.