Evaluation and Treatment of Knee Pain: A Review.

Importance: Approximately 5% of all primary care visits in adults are related to knee pain. Osteoarthritis (OA), patellofemoral pain, and meniscal tears are among the most common causes of knee pain. Observations: Knee OA, affecting an estimated 654 million people worldwide, is the most likely diagnosis of knee pain in patients aged 45 years or older who present with activity-related knee joint pain with no or less than 30 minutes of morning stiffness (95% sensitivity; 69% specificity). Patellofemoral pain typically affects people younger than 40 years who are physically active and has a lifetime prevalence of approximately 25%. The presence of anterior knee pain during a squat is approximately 91% sensitive and 50% specific for patellofemoral pain. Meniscal tears affect an estimated 12% of the adult population and can occur following acute trauma (eg, twisting injury) in people younger than 40 years. Alternatively, a meniscal tear may be a degenerative condition present in patients with knee OA who are aged 40 years or older. The McMurray test, consisting of concurrent knee rotation (internal or external to test lateral or medial meniscus, respectively) and extension (61% sensitivity; 84% specificity), and joint line tenderness (83% sensitivity; 83% specificity) assist diagnosis of meniscal tears. Radiographic imaging of all patients with possible knee OA is not recommended. First-line management of OA comprises exercise therapy, weight loss (if overweight), education, and self-management programs to empower patients to better manage their condition. Surgical referral for knee joint replacement can be considered for patients with end-stage OA (ie, no or minimal joint space with inability to cope with pain) after using all appropriate conservative options. For patellofemoral pain, hip and knee strengthening exercises in combination with foot orthoses or patellar taping are recommended, with no indication for surgery. Conservative management (exercise therapy for 4-6 weeks) is also appropriate for most meniscal tears. For severe traumatic (eg, bucket-handle) tears, consisting of displaced meniscal tissue, surgery is likely required. For degenerative meniscal tears, exercise therapy is first-line treatment; surgery is not indicated even in the presence of mechanical symptoms (eg, locking, catching). Conclusions and Relevance: Knee OA, patellofemoral pain, and meniscal tears are common causes of knee pain, can be diagnosed clinically, and can be associated with significant disability. First-line treatment for each condition consists of conservative management, with a focus on exercise, education, and self-management.

Prevalence of Trochlear Dysplasia and Associations with Patellofemoral Pain and Instability in a Skeletally Mature Population.

BACKGROUND: Patellar instability among adolescents has an incidence of 29 to 43 per 100,000 per year. Trochlear dysplasia has been found in up to 85% of those with recurrent patellar instability. The prevalence of trochlear dysplasia in the general population has not yet been defined. The purpose of the present study was to determine the prevalence of trochlear dysplasia as defined by ultrasound in a skeletally mature population and to characterize associations of trochlear dysplasia with a history of patellofemoral instability or pain. METHODS: Skeletally mature adolescents and parents of patients (≤50 years of age) who had presented to orthopaedic clinics were prospectively enrolled from 2019 to 2020. Those presenting with knee pain, open physes, prior intra-articular fracture, total knee arthroplasty, and syndromic ligamentous laxity or neuromuscular disease were excluded. Information regarding a history of anterior knee pain, patellar instability, and/or surgery was obtained, and an abbreviated Anterior Knee Pain Scale (AKPS) was collected. An AKPS score of ≥4 was considered positive. Bilateral ultrasound of the knee was performed, and the osseous sulcus angle of the trochlea and the trochlear depth were measured. Basic descriptive statistics are reported. RESULTS: One hundred and two patients (203 knees) were studied. The mean sulcus angle was 144.1° ± 6.8°, and the mean trochlear depth was 5.5 ± 1.4 mm. High-grade trochlear dysplasia was defined as the 95th percentile and above, which was shown to be a sulcus angle of ≥154° or a trochlear depth of ≤3 mm for female patients and ≤4 mm for male patients. The prevalence of high-grade trochlear dysplasia was 5.4% based on the sulcus angle and 9.9% based on trochlear depth. Knees with high-grade trochlear dysplasia based on the sulcus angle were 11 times more likely to have had previous patellar instability (p = 0.013). CONCLUSIONS: The prevalence of high-grade trochlear dysplasia in the general population is approximately 10%, and there may be an association with patellar instability. The use of ultrasound to diagnose trochlear dysplasia may prove to be a rapid and useful tool for guiding patient education and treatment decisions. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Validation of the cultural adaptation of the Kujala score in Arabic.

BACKGROUND: Patellofemoral pain is a common condition. The Kujala score is a well-established scoring system to assess anterior knee pain and has been translated into many languages including Arabic. The purpose of this cross-sectional study is to culturally adapt the Arabic version of the Kujala score and determine its validity. METHODS: The Kujala score is composed of 13 multiple-choice questions. We modified two questions in the score; running and squatting, and were replaced with questions related to walking on different terrain and prostration, each with the same number of answer choices as the original questions so as not to affect the final score. These modifications were written in Arabic by the same group who translated and validated the original score into Arabic. The original and modified Kujala scores was printed and given to patients complaining of patellofemoral pain to be filled during their visit to the orthopedic outpatient clinics. Final scores for the original and modified questionnaires were calculated. Data was analyzed using SPSS statistics version 21.0 measuring Cronbach's alpha, intraclass correlation coefficient, and Pearson correlation. RESULTS: Ninety-four patients were included in the study, 28 (29.8%) men and 66 (70.2%) women. The mean age for the included patients was 43.67 (± 14.46) years. The mean score for the modified initial questionnaire was 63.91 (± 16.32), and the mean score for the modified re-test questionnaire was 66.52 (± 17.50). There was a statistically significant difference between the mean scores (p = 0.041), with a mean difference of 1.97 (95% CI 0.08 to 3.856). We found a significant strong correlation between the score before and after changing the questions with a p value of < 0.001. CONCLUSIONS: The culturally modified Arabic Kujala questionnaire is shown to be a valid, well-designed tool and an appropriate method of measuring patellofemoral pain.

Different Patellar Indices and Their Role in Decision-Making: An MRI-Based Study.

Magnetic resonance imaging (MRI) of knee has become the integral part of knee evaluation, hence any MRI based study adds more value if it helps in the decision-making process, especially for surgery in treating patellofemoral pain. We tried to determine normal patellar indices using knee MR images and the correlation between them and also compared the results with different ethnic population. We analyzed the prospectively collected MR images of 117 knees/patients, and Insall-Salvati (IS) index, modified IS index, patellotrochlear (PT) index, and patellophyseal (PP) index were calculated. Two standard deviations from the mean were used to define the normal and abnormal patellar position. Cohen's kappa values were used to assess the agreement between the indices and the correlation between them was analyzed using Pearson's correlation. The mean values for IS index, modified IS index, PT index, and PP index were 1.00, 1.53, 0.40, and 0.58, respectively. There was very good agreement between PT index and PP index. There was weak correlation between all the indices except the one between PT and PP indices which had a strong negative correlation. Based on commonly used methodology, there were 4% of asymptomatic patients who were outside the standardized cut-off values and different indices classified different knees as abnormal. This indicates patellar position should be one among the many other factors, not as a sole factor when making a surgical decision in patellofemoral pain. We also noted that the indices compared fairly with other populations. Further research is needed to determine the clinical applicability of these indices.

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

BACKGROUND: Patellar maltracking is widely accepted as an underlying mechanism of patellofemoral pain. However, methodological differences in the literature hinder our ability to generate a universal quantitative definition of pathological patellofemoral kinematics (patellar maltracking) in patellofemoral pain, leaving us unable to determine the cause of patellofemoral pain. PURPOSE: To systematically review the literature to provide evidence regarding the influence of confounding variables on patellofemoral kinematics. STUDY DESIGN: Systematic review and random effects meta-analysis of control-case studies. METHODS: A literature search of case-control studies that evaluated patellofemoral kinematics at or near full extension and were written in English was conducted using Embase, PubMed, Scopus, and Web of Science up to September 2019. Cases were defined as patients with patellofemoral pain. Studies were eliminated if they lacked quantitative findings; had a primary aim to assess therapy efficacy; or included participants with osteoarthritis and/or previous trauma, pathology, or surgery. A quality assessment checklist was employed to evaluate each study. Meta-analyses were conducted to determine the influence of confounding variables on measures of patellofemoral kinematics. RESULTS: Forty studies met the selection criteria, with quality scores ranging from 13% to 81%. Patient characteristics, data acquisition, and measurement methods were the primary sources of methodological variability. Active quadriceps significantly increased lateral shift (standardized mean difference [SMD]shift = 0.33; P = .0102) and lateral tilt (SMDtilt = 0.43; P = .006) maltracking. Individuals with pain secondary to dislocation had greater effect sizes for lateral maltracking than had those with isolated patellofemoral pain (ΔSMDshift = 0.71, P = .0071; ΔSMDtilt = 1.38, P = .0055). CONCLUSION: This review exposed large methodological variability across the literature, which not only hinders the generalization of results, but ultimately mitigates our understanding of the underlying mechanism of patellofemoral pain. Although our meta-analyses support the diagnostic value of maltracking in patellofemoral pain, the numerous distinct methods for measuring maltracking and the limited control for cofounding variables across the literature prohibit defining a single quantitative profile. Compliance with specific standards for anatomic and outcome measures must be addressed by the scientific and clinical community to establish methodological uniformity in this field.

Effects of a 12-week home exercise therapy program on pain and neuromuscular activity in patients with patellofemoral pain syndrome.

INTRODUCTION: The aim of this study is to evaluate the effects of a 12-week home exercise therapy program on pain, function and neuromuscular activity of the vastus medialis and vastus lateralis. MATERIALS AND METHODS: Fifty patients with patellofemoral pain syndrome were treated with a 12-week online home exercise program. The primary outcomes of pain and function were assessed at the 12-week follow-up using the Visual Analog Scale and Kujala Score, respectively. Secondary outcomes were the muscle onset time and the ratio of vastus medialis and vastus lateralis during different daily activities. RESULTS: After 12 weeks, patients showed significant (p < 0.05) improvements of 27 points on the Visual Analog Scale and 10 points on Kujala Score. Differences in pre-post comparison regarding both temporal and amplitude-related neurophysiological differences between the vastus medialis and lateralis were only found when the subjects were divided into groups of different electromyographic patterns. Then changes in the pre-post comparison were particularly evident in the patient group with a delayed vastus medialis onset and a lower activity of the vastus medialis compared to the VL. CONCLUSION: Pain and function improved significantly after a home exercise therapy program in patients with patellofemoral pain syndrome. In addition, patients with a delayed onset or reduced activity of the vastus medialis compared to the vastus lateralis experienced a reduction in this imbalance.

Lower extremity alignment due to patellofemoral syndrome and dynamic postural balance.

STUDY DESIGN: This study is a prospective study. AIM: Lower extremity malalignment is an important etiologic factor in patellofemoral pain syndrome (PFPS). We hypothesized that lower limb malalignment may affect dynamic balance and physical function. This prospective study was conducted to investigate the relationship between the lower limb alignment and the dynamic balance and physical function in patients with PFPS. METHODS: The study included 62 individuals with unilateral PFPS. Pain severity was assessed by the numerical pain scale and the pain duration was recorded. Lower extremity bone alignment was evaluated by the lateral distal femoral angle (LDFA) and the medial proximal tibia angle. Dynamic postural balance was assessed by the star excursion balance test. The functional status of the patients was evaluated by the 30-second chair stand test. RESULTS: The mean duration of the pain was 24.2 ± 31.5 months and the mean pain severity was 8.1 ± 1.4. Although there was a significant difference found between the affected and unaffected LDFA values of lower extremities (p < 0.05), there was no difference found with regard to the dynamic balance values of the lower extremities (p > 0.05). However, significant changes of posterolateral balance were identified at a painful side without causing a postural dynamic imbalance (p < 0.05). CONCLUSION: In our study, we found a valgus deformity as a deterioration in the lower limb alignment of patients with PFPS which may cause a deterioration of posterolateral balance only. However, no change in postural dynamic balance was observed in the comparison of affected side and unaffected side. Dynamic postural balance has been influenced by many kinematic changes related to lower extremities including pelvis, hip, and ankle. Thus, reciprocal mechanisms in the anatomical structures may compensate the postural balance dynamically.

The Aberdeen Weight-Bearing Test (Knee): a new objective test for anterior knee discomfort.

PURPOSE: We present the Aberdeen Weight-Bearing Test (Knee), an objective test specific for anterior knee discomfort assessed via load bearing. We assess its validity by performing it on normal subjects with no knee symptoms and subjects who had undergone anterograde tibial nailing. METHODS: Two scales are placed parallel on the floor with the dials concealed from the subject. The subject then kneels with one knee on each scale. The weight through each knee is recorded at 0, 15, 30, 45, and 60 s. The proportion of total body weight on each leg at each timepoint is calculated, and a ratio calculated from the values. A value of 1 equates to equal weight on each leg. The test was performed on 53 normal subjects and 38 subjects who had undergone tibial nailing. RESULTS: In the normal group, no significant difference in mean ratio of weight distribution (left:right) was seen at any timepoint (mean ratio range = 0.98-0.99, p value range = 0.18-0.64). In the tibial nail group, a difference was observed in mean ratio of weight distribution (injured:uninjured) favouring the uninjured leg, reaching significance at 0, 15, 30, and 45 s (mean ratio range = 0.88-0.94, p value range = 0.01-0.02). At 60 s, the mean ratio was 0.93 (p = 0.09). CONCLUSION: The Aberdeen Weight-Bearing Test (Knee) is an objective, easily reproducible, specific test for anterior knee discomfort. It produces different results in individuals who have undergone anterograde tibial nailing compared to individuals with no knee symptoms.

Patellofemoral Pain Syndrome.

Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain encountered in the outpatient setting in adolescents and adults younger than 60 years. The incidence in the United States is between 3% and 6%. The cardinal feature of PFPS is pain in or around the anterior knee that intensifies when the knee is flexed during weight-bearing activities. The pain of PFPS often worsens with prolonged sitting or descending stairs. The most sensitive physical examination finding is pain with squatting. Examining a patient's gait, posture, and footwear can help identify contributing causes. Plain radiographs of the knee are not necessary for the diagnosis of PFPS but can exclude other diagnoses, such as osteoarthritis, patellar fracture, and osteochondritis. If conservative treatment measures are unsuccessful, plain radiography is recommended. Treatment of PFPS includes rest, a short course of nonsteroidal anti-inflammatory drugs, and physical therapy directed at strengthening the hip flexor, trunk, and knee muscle groups. Patellar kinesiotaping may provide additional short-term pain relief; however, evidence is insufficient to support its routine use. Surgery is considered a last resort.

Higher pain level and lower functional capacity are associated with the number of altered kinematics in women with patellofemoral pain.

This study investigated whether women with patellofemoral pain (PFP) present kinematic alterations in proximal, local, and distal factors simultaneously, and determined the association between the number of kinematic alterations, pain level, and functional status. A three-dimensional motion analysis system was used to analyze the peak hip adduction, peak knee flexion, and peak rearfoot eversion, addressing the proximal, local, and distal factors, respectively, in fifty women. Functional status and pain level were assessed using the anterior knee pain scale (AKPS) and a visual analogic scale. Receiver operating characteristic curves were calculated to identify participants with and without kinematic alterations and the number of them was obtained for each participant. Associations between the number of kinematic alterations, pain level, and AKPS score were determined by the Pearson correlation. Results showed that 52% of women with PFP presented at least two kinematic alterations of which 24% were local/proximal, 16% local/distal, and 12% proximal/distal. Three kinematic alterations were found in 48% of the women with PFP. A strong positive correlation was found between the number of kinematic alterations and pain (r=0.78; p<0.001). A strong negative correlation was found between the number of altered kinematics and functional status (r=-0.79; p<0.001). Findings revealed that women with PFP presented at least two kinematic alterations and a higher number of kinematic alterations was associated with higher pain levels and lower functional status. Clinicians should carefully assess movement pattern of women with PFP as it could indicate a more severe condition, which is associated with a poor prognosis.

[Running and causes of running-related injuries].

Running is one of the most popular sports among the adult Danish population. Overuse injuries of the knee, such as runners knee, jumpers knee, patello-femoral pain syndrome and patello-femoral pre-arthrosis, are common and cause reduction of the health beneficial physical activity. Treatment should primarily focus on adjustment of training habits and physiotherapeutic guided rehabilitation. Other treatment options include changing landing pattern during running, corticosteroid injections, non-steroid anti-inflammatory drugs and ultimately surgery.

Acute Responses of Strength and Running Mechanics to Increasing and Decreasing Pain in Patients With Patellofemoral Pain.

CONTEXT: Patellofemoral pain (PFP) is typically exacerbated by repetitive activities that load the patellofemoral joint, such as running. Understanding the mediating effects of changes in pain in individuals with PFP might inform injury progression, rehabilitation, or both. OBJECTIVE: To investigate the effects of changing pain on muscular strength and running biomechanics in those with PFP. DESIGN: Crossover study. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Seventeen participants (10 men, 7 women) with PFP. INTERVENTION(S): Each participant completed knee pain-reducing and pain-inducing protocols in random order. The pain-reducing protocol consisted of 15 minutes of transcutaneous electric nerve stimulation (TENS) around the patella. The pain-inducing protocol was sets of 20 repeated single-legged squats (RSLS). Participants completed RSLS sets until either their pain was within at least 1 cm of their pain during an exhaustive run or they reached 10 sets. MAIN OUTCOME MEASURE(S): Pain, isometric hip and trunk strength, and running mechanics were assessed before and after the protocols. Dependent variables were pain, normalized strength (abduction, extension, external rotation, lateral trunk flexion), and peak lower extremity kinematics and kinetics in all planes. Pain scores were analyzed using a Friedman test. Strength and mechanical variables were analyzed using repeated-measures analyses of variance. The α level was set at P < .05. RESULTS: Pain was decreased after the TENS (pretest: 3.10 ± 1.95, posttest: 1.89 ± 2.33) and increased after the RSLS (baseline: 3.10 ± 1.95, posttest: 4.38 ± 2.40) protocols (each P < .05). The RSLS protocol resulted in a decrease in hip-extension strength (baseline: 0.355 ± 0.08 kg/kg, posttest: 0.309 ± 0.09 kg/kg; P < .001). Peak plantar-flexion angle was decreased after RSLS (baseline: -13.97° ± 6.41°, posttest: -12.84° ± 6.45°; P = .003). Peak hip-extension (pretest: -2.31 ± 0.46) and hip-abduction (pretest: -2.02 ± 0.35) moments decreased after both the TENS (extension: -2.15 ± 0.48 Nm/kg, P = .015; abduction: -1.91 ± 0.33 Nm/kg, P = .015) and RSLS (extension: -2.18 ± 0.52 Nm/kg, P = .003; abduction: -1.87 ± 0.36 Nm/kg, P = .039) protocols. CONCLUSIONS: This study presents a novel and effective method of increasing pain in persons with PFP. Functionally increased pain after RSLS coincides with reduced hip-extensor muscle strength and decreased plantar-flexion angle during running. The TENS treatment decreased pain during running in those with PFP but failed to influence strength. Hip moments were reduced by both protocols, which may demonstrate that acute increases or decreases in pain cause runners to change their mechanics.

A questionnaire to identify patellofemoral pain in the community: an exploration of measurement properties.

BACKGROUND: Community-based studies of patellofemoral pain (PFP) need a questionnaire tool that discriminates between those with and those without the condition. To overcome these issues, we have designed a self-report questionnaire which aims to identify people with PFP in the community. STUDY DESIGNS: comparative study and cross-sectional study. STUDY POPULATION: comparative study: PFP patients, soft-tissue injury patients and adults without knee problems. Cross-sectional study: adults attending a science festival. INTERVENTION: comparative study participants completed the questionnaire at baseline and two weeks later. Cross-sectional study participants completed the questionnaire once. The optimal scoring system and threshold was explored using receiver operating characteristic curves, test-retest reliability using Cohen's kappa and measurement error using Bland-Altman plots and standard error of measurement. Known-group validity was explored by comparing PFP prevalence between genders and age groups. RESULTS: Eighty-four participants were recruited to the comparative study. The receiver operating characteristic curves suggested limiting the questionnaire to the clinical features and knee pain map sections (AUC 0.97 95 % CI 0.94 to 1.00). This combination had high sensitivity and specificity (over 90 %). Measurement error was less than the mean difference between the groups. Test-retest reliability estimates suggest good agreement (N = 51, k = 0.74, 95 % CI 0.52-0.91). The cross-sectional study (N = 110) showed expected differences between genders and age groups but these were not statistically significant. CONCLUSION: A shortened version of the questionnaire, based on clinical features and a knee pain map, has good measurement properties. Further work is needed to validate the questionnaire in community samples.

Translation, cross-cultural adaptation and validation of the Turkish version of the Lower Extremity Functional Scale on patients with knee injuries.

INTRODUCTION: The Lower Extremity Functional Scale is a widely used questionnaire to evaluate the functional impairment in lower extremities. To date, the Lower Extremity Functional Scale has not been translated into Turkish. The aim of this study is to translate and culturally adapt the Lower Extremity Functional Scale into a Turkish version, and evaluate the psychometric properties of this version in patients with knee injuries. MATERIALS AND METHODS: The translation of the English version of the Lower Extremity Functional Scale into a Turkish version was performed using standard guidelines. Validity and reliability of Turkish version were tested in 134 patients with knee injuries. Association level between other outcomes measures (Kujala Patellofemoral Score, the Western Ontario and McMaster Universities Osteoarthritis Index, Lysholm Knee Scoring Scale and a Visual Analog Scale) and Turkish version of the Lower Extremity Functional Scale was analyzed to assess validation. Participants completed the questionnaire at baseline and after 2 days to test reliability. RESULTS: The Turkish version of the Lower Extremity Functional Scale was showed a high degree of internal consistency (Cronbach α = 0.93). ICCs were 0.96 and no floor or ceiling effects. The Lower Extremity Functional Scale had a high level of association with the Kujala Patellofemoral Score (r = 0.82), Lysholm Knee Scoring Scale (r = 0.80) and the Western Ontario and McMaster Universities Osteoarthritis Index scores (r = 0.69) (all, p < 0.05). CONCLUSION: The Turkish version of the Lower Extremity Functional Scale is a valid and reliable questionnaire that can be used to evaluate functional status in Turkish speaking patients with different knee disorders. LEVEL OF EVIDENCE: III.

Validation and cultural adaptation of "Kujala Score" in Spanish.

PURPOSE: To translate the patellofemoral disorder questionnaire "Kujala Score" into Spanish and to adapt it for Spanish culture . METHODS: International recommendations were followed to translate the "Kujala Score" into Spanish together with a cultural adaptation and validation. We analysed the following parameters: internal consistency, agreement construct validity, test-retest reliability, ceiling and floor effects, and responsiveness. The reproducibility and responsiveness were tested in 72 patients with patellofemoral pain syndrome in a test-retest design with follow-up testing at 7 days. The "Kujala Score" and the VISA-P were administered to 98 patients and 30 patients, respectively, who completed the "Kujala Score" and VISA-P after physiotherapy treatment, which consisted of rest, ice, proprioceptive exercise and manual therapy. RESULTS: The Spanish "Kujala Score" had high internal consistency (Cronbach α = 0.8; if an item was deleted, Cronbach α = 0.77-0.80), excellent reliability and agreement (interclass correlation coefficient = 0.99), and good construct validity that was significantly correlated with the outcome of the Spanish VISA-P (Spearman rho = 0.7; P < 0.001). No ceiling or floor effects was detected for the Spanish "Kujala Score" or the responsiveness of the participants based on 40 patients receiving physical therapy, rest, ice and proprioceptive exercises for 1 month, demonstrating that it is a good determinant of changes in the symptomatology of patients with knee pain. CONCLUSIONS: The Spanish adaptation of the patellofemoral disorder questionnaire "Kujala Score" proved to be valid and sensitive to clinical changes and to be a reliable instrument to assess the severity of pain and disability in patients with patellofemoral disorders. This questionnaire will be useful in clinical practice and research as an appropriate tool to evaluate and record the symptomatology of patients with patellofemoral pain syndrome among Spanish population. LEVEL OF EVIDENCE: Diagnostic study, Level I.

Analysis of patient-reported anterior knee pain scale: implications for scale development in children and adolescents.

PURPOSE: The purpose of this investigation was to estimate and document the reliability and validity of the Anterior Knee Pain Scale (AKPS) and to estimate its relative prediction accuracy of anterior knee pain in young females. METHODS: Data from a prospective, epidemiologic study to diagnose patellofemoral knee pain among female athletes (n = 499) using the Anterior Knee Pain Scale (AKPS). Data were treated in 4 phases (descriptive phase, reliability phase, scale refinement phase) and a final validation stage that was focused on an effort to test and document the validation of the AKPS short form and perform head-to-head comparisons of the 6-item short form with the original, 13-item form. RESULTS: The AKPS was reduced from 13 items (αCoeff = 0.77, σSEM = 0.004) to 6 items (αCoeff = 0.78, σSEM = 0.004). Point-biserial correlations with patellofemoral pain diagnosis were comparable: r [498] = 0.70 (R(2) = 0.49, short form) and r [498] = 0.71 (R(2) = 0.51, long form), as was sensitivity: 84% (short form) and 80% (long form), and specificity: 89% (short form) and 90% (long form; AUC = 0.94 both). CONCLUSION: The current analyses indicate that a subset of measures from the AKPS is responsive to patellofemoral pain symptoms and may support screening for related diagnoses. A simpler and quicker scale optimized for diagnostic accuracy could reduce the demand on patients, clinicians and research teams focused on the identification and management of patellofemoral pain. LEVEL OF EVIDENCE: III.

Test de Zohlen y su relación con el ángulo Q en población sin dolor patelofemoral / Zohlen's test and its relation to the Q angle in a population without patellofemoral pain

Determinar qué porcentaje de una población sin dolor anterior de rodilla tiene un test de Zohlen positivo, además determinar el ángulo Q de esta población y buscar si existe alguna relación entre la positividad del test de Zohlen y alteraciones en el ángulo Q. Material y método: Estudio descriptivo-prospectivo observacional. Aplicación del test de Zohlen y medición del ángulo Q. La población se dividió en 2 grupos: test de Zohlen positivo y test de Zohlen negativo. Cuantificación y comparación de medias del ángulo Q en los dos grupos. Resultados: 90 sujetos evaluados, promedio de edad 20,18 años (18-40). Veinte sujetos (22,2 por ciento) con test de Zohlen positivo. Ángulo Q promedio en los sujetos con test de Zohlen negativo: 14,95°; ángulo Q promedio en los sujetos con test de Zohlen positivo: 16,9° (p < 0,05). Ángulo Q promedio en hombres con test de Zohlen negativo 13,4°; ángulo Q promedio en hombres con test de Zohlen positivo: 16° (p < 0,05). Ángulo Q promedio en mujeres con test de Zohlen negativo: 16,5°; ángulo Q promedio en mujeres con test de Zohlen positivo: 18°, sin diferencias estadísticamente significativas entre ambos grupos. Conclusiones: El test de Zohlen tiene una correlación positiva con el ángulo Q en sujetos de sexo masculino. Dada la correlación entre un ángulo Q alterado y la presencia de dolor anterior de rodilla, en los pacientes que presentan un test de Zohlen positivo sin haber consultado por dolor anterior de rodilla, la prevención primaria de dolor anterior de rodilla puede ser de utilidad...

To determine the percentage of a population without anterior knee pain with a positive Zohlen test, and also to determine the Q angle of this population and to determine if there is any relationship between the Zohlen test and Q angle anomalies. Methods:A prospective observational study was conducted in which Zohlen¿s test was applied and the Q angle was measured. The population was divided into 2 groups: Zohlen¿s positive and Zohlen¿s negative. Q angle was compared in the 2 groups. Results: The study included 90 subjects, with a mean age 20.18 years (18-40), of whom 20 subjects (22.2 percent) had positive Zohlen¿s test. The mean Q angle in subjects with negative Zohlen¿s test was 14.95°, and the mean Q angle in subjects with positive Zohlen¿s test was 16,9° (p<.05). The mean Q angle in men with negative Zohlen¿s test was 13.4°, and the mean Q angle in men with positive Zohlen¿s test was 16° (p < .05). The mean Q angle in women with negative Zohlen¿s test was 16.5°, with a mean Q angle of 18° in women with positive Zohlen¿s test, with no statistically significant differences found between groups. Conclusions: Zohlen¿s test has a positive correlation with the Q angle in male subjects. Given the correlation between the Q angle and the presence of anterior knee pain in patients who have a positive test without symptoms, primary prevention of anterior knee pain can be achieved...

Knee Pain and Patellofemoral Symptoms in Patients With Cerebral Palsy.

BACKGROUND: Knee pain in cerebral palsy (CP) is associated with increased patellofemoral forces present when walking with flexed knees. In typically developing children, knee pain and patellofemoral dysfunction are associated with obesity, genu valgum, femoral anteversion, and external tibial torsion. These problems are also common in CP, and may contribute to knee problems in this population. The purposes of this study were to define the prevalence of knee pain and patellofemoral dysfunction in children with CP, and to identify physical and gait characteristics (using 3-dimensional gait analysis data) that predispose them to such problems. METHODS: Retrospective review of 121 children with CP, Gross Motor Function Classification System level I to IV, who underwent computerized gait analysis testing. Demographics, range of motion, body mass index and hip, knee, and ankle kinematics were compared between subjects with and without knee pain. RESULTS: Twenty-five of 121 subjects (21%) reported knee pain at the time of testing. Three of 121 subjects (2%) had a history of patellar subluxation/dislocation. Age and sex were significantly related to presence of knee pain. The likelihood of knee pain was almost 5 times higher in females (odds ratio=4.9, [95% confidence interval, 1.8-13.3], P=0.002), with a prevalence of 40% (17/42) in females versus 10% (8/79) in males. The likelihood of knee pain increased with age by approximately 13% per year (odds ratio=1.13, [95% confidence interval, 1.00-1.28], P=0.058). Malignant malalignment syndrome showed a potential relationship to more severe knee pain (P=0.05), which warrants further investigation. Body mass index, pes valgus, and degree of stance knee flexion showed no statistically significant relationships to knee pain (P>0.16). CONCLUSIONS: The prevalence of knee pain in ambulatory patients with CP is approximately 21%. Patellar subluxation (2%) and dislocation are rare in these patients. Knee pain is not always related to crouch, femoral anteversion, external tibial torsion, genu valgum, or pes valgus. Knee pain in these patients is more prevalent in females, and increases with increasing age. LEVEL OF EVIDENCE: Level III-case-control study.

The Patella Pro study - effect of a knee brace on patellofemoral pain syndrome: design of a randomized clinical trial (DRKS-ID:DRKS00003291).

BACKGROUND: Patellofemoral pain syndrome (PFPS) is a frequent cause of anterior knee pain predominantly affecting young female patients who do not have significant chondral damage. Development of PFPS is probably multifactorial, involving various knee, hip, and foot kinematic factors. Biomechanical studies have described patellar maltracking and dynamic valgus (functional malalignment) in patients with patellofemoral pain syndrome. The literature provides evidence for short-term use of nonsteroidal anti-inflammatory drugs; short-term medially directed taping; and exercise programs focusing on the lower extremity, hip, and trunk muscles. Evidence supporting the use of patellar braces is limited because previous studies have been low quality. The aim of this article is to publish the design of a prospective randomized trial that examines the outcomes of patients with PFPS after treatment with a new patellar brace (Patella Pro) that applies medially directed force on the patella. METHODS/DESIGN: For this multicenter trial, 156 patients (adolescents and young adults) with PFPS were recruited from orthopedic practices and orthopedic hospitals and randomly allocated to 3 months of supervised physiotherapy in combination with the Patella Pro brace or supervised physiotherapy alone. The primary outcome measures are pain (numerical analog scale); knee function (Kujala score and Knee Injury and Osteoarthritis Outcome Score); and self-reported perception of recovery at baseline, 6 weeks, 3 months, and 1 year. DISCUSSION: Only limited evidence for the use of a patellar brace for the treatment of PFPS exists in the literature. Disputable evidence for the use of orthoses for PFPS patients has been presented in one meta-analysis, in which only one of three studies found the effect of a medially directed patellar brace to be significant. Because of these low-quality studies, the authors concluded that this evidence should be regarded as limited, and we feel there is a need for further well-designed studies to evaluate the effect of patellar bracing on PFPS-related pain. The Patella Pro study is a prospective randomized trial in which supervised physiotherapy in combination with a patellar brace is compared with supervised physiotherapy alone. This trial started in April 2012 and finished in October 2013. TRIAL REGISTRATION: DRKS-ID:DRKS00003291, January 3rd, 2012.