Purpose:To evaluate patellar kinematics of volunteers without knee pain at rest and during isometric contraction in open-and closed-kinetic-chain exercises. Methods: Twenty individuals took part in this study. All were submitted to magnetic resonance imaging (MRI) during rest and voluntary isometric contraction (VIC) in the open and closed kinetic chain at 15°, 30°, and 45° of knee flexion. Through MRI and using medical e-film software, the following measurements were evaluated: sulcus angle, patellar-tilt angle, and bisect offset. The mixed-effects linear model was used for comparison between knee positions, between rest and isometric contractions, and between the exercises. Results: Data analysis revealed that the sulcus angle decreased as knee flexion increased and revealed increases with isometric contractions in both the open and closed kinetic chain for all kneeflexion angles. The patellar-tilt angle decreased with isometric contractions in both the open and closed kinetic chain for every knee position. However, in the closed kinetic chain, patellar tilt increased significantly with the knee flexed at 15°. The bisect offset increased with the knee flexed at 15° during isometric contractions and decreased as knee flexion increased during both exercises. Conclusion: VIC in the last degrees of knee extension may compromise patellar dynamics. On the other hand, it is possible to favor patellar stability by performing muscle contractions with the knee flexed at 30° and 45° in either the open or closed kinetic chain.

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The purpose of this study was to correlate the trochlear shape and patellar tilt angle and lateral patellar displacement at rest and maximal voluntary isometric contraction (MVIC) exercises during open (OKC) and closed kinetic chain (CKC) in subjects with and without anterior knee pain. Subjects were all women, 20 who were clinically healthy and 19 diagnosed with anterior knee pain. All subjects were evaluated and subjected to magnetic resonance exams during OKC and CKC exercise with the knee placed at 15, 30, and 45 degrees of flexion. The parameters evaluated were sulcus angle, patellar tilt angle and patellar displacement using bisect offset. Pearson's r coefficient was used, with p < .05. Our results revealed in knee pain group during CKC and OKC at 15 degrees that the increase in the sulcus angle is associated with a tilt increase and patellar lateral displacement. Comparing sulcus angle, patellar tilt angle and bisect offset values between MVIC in OKC and CKC in the knee pain group, it was observed that patellar tilt angle increased in OKC only with the knee flexed at 30 degrees. Based on our results, we conclude that reduced trochlear depth is correlated with increased lateral patellar tilt and displacement during OKC and CKC at 15 degrees of flexion in people with anterior knee pain. By contrast, 30 degrees of knee flexion in CKC is more recommended in rehabilitation protocols because the patella was more stable than in other positions.

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OBJECTIVE: As patellofemoral pain syndrome (PFPS) is a common disorder characterized by multifactorial etiology and whose the most prevalent symptom is a diffuse pain, usually located on the retropatellar region, however, it also shows signs and symptoms that can be related as excessive subtalar pronation, external tibial torsion, patellar displacement alterations, painful range of motion of the knee, pain in the patellar borders, muscular tightness and changes in quadriceps angle (Q Angle), the objective of this work was to determine the frequency of these signs and symptoms associated to a previous knee pain questionnaire. METHODS: Thirty-nine sedentary female volunteers had been evaluated, divided in two groups, PFPS (19) and Control (20). These subjects were evaluated for signs and symptoms described above, in addition to pain assessment by questionnaire. RESULTS: The results demonstrated a high frequency of pain in six of the thirteen questions in relation to the control group. CONCLUSION: According to these findings, we conclude that the functional evaluation of individuals with PFPS should consist of a previous knee pain questionnaire and an evaluation of the characteristic signs and symptoms for examination of the entire lower limb during static and functional situations. Level of Evidence II, Diagnostic Studies.

OBJECTIVE: To evaluate the patellar height of volunteers with and without patellofemoral pain syndrome (PPS) during maximal voluntary isometric contraction (MVIC) in open kinetic chain (OKC) and closed kinetic chain (CKC) exercises. METHODS: Twenty healthy women, and nineteen women with patellofemoral pain syndrome were evaluated and subjected to nuclear magnetic resonance imaging during rest and MVIC in OKC and CKC at 15°, 30°, and 45° knee flexion. The patellar height was assessed by the K-Pacs program,using the Insall-Salvati index. For each exercise and knee position, patellar height was measured three times and the procedure was repeated after seven days. RESULTS: These data did not confirm our hypothesis that OKC exercises promote increased patellar height. CONCLUSION: Patellar height is not associated with PPS and suggests that CKC exercises lead an increased patellar height during knee position at 15º and 45º flexion for the PPS group. Level of Evidence II, Comparative Prospective.

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