P.R. Serrão

Knee extensor torque of men with early degrees of osteoarthritis is associated with pain, stiffness and function

BACKGROUND Osteoarthritis (OA) is a chronic-degenerative disease. The knee is the most commonly affected joint and the symptoms are generally attributed to quadriceps muscle weakness. However, few studies have evaluated this relationship in a population with early stages of knee OA. OBJECTIVE To investigate whether a correlation among the knee extensor torque and the three subscales of the WOMAC questionnaire in men with early stages of knee OA exists. METHOD Twenty-one men with knee OA grades I or II (according to Kellgren and Lawrence criteria) participated in this study. The concentric and eccentric knee extensor torque were assessed using a Biodex System 3 Pro® isokinetic dynamometer, at a speed of 90º/s. Self-reported symptoms and disability were assessed using the WOMAC questionnaire. Spearmans correlation coefficient was used to test the relationship between the dependent variables (three subscales of WOMAC questionnaire) and the independent variables (average knee extensor peak torque). RESULTS We found a strong negative correlation between the concentric extensor torque and pain (r=-0.7, p<0.001) and a moderate and negative correlation among the concentric extensor torque and stiffness (r=-0.62, p=0.002) and physical function (r=-0.54, p=0.011). Eccentric extensor torque presented a moderate and negative correlation with the three subscales of the WOMAC (r=-0.40 to 0.69, p<0.05). CONCLUSIONS The concentric and eccentric knee extensor torque is significantly correlated with self-report symptoms of patients in initial stages of knee OA. Therefore, the strengthening of the quadriceps muscles, through concentric and eccentric exercise is indicated for these patients in order to minimize these symptoms.

Male subjects with early-stage knee osteoarthritis do not present biomechanical alterations in the sagittal plane during stair descent

Patients with osteoarthritis (OA) of the knee show a loss of functional independence due to difficulty performing tasks that require high demand of the knee joint, such as descending stairs. However, it is unclear how muscular and biomechanical changes were present in patients with OA in the early stages. Thus, the purpose of this study was to analyze the kinetics, kinematics and muscle activation of men with early-stage knee OA during stair descent and compare them with a healthy control group. We evaluated 31 volunteers who were divided into two groups. The Osteoarthritis Group (OAG) included 17 men with grade I or II knee OA (53 ± 6 years) and the Control Group (CG) included 14 healthy men (50 ± 6 years). We performed a kinematic evaluation of stair descent in the sagittal plane in order to analyze knee flexion angles. Electromyography (EMG) of the vastus lateralis muscle was also performed and the vertical ground reaction force was measured. The WOMAC questionnaire was administered to all volunteers. Statistical analysis consisted of the nonparametric Mann-Whitney U test for intergroup comparisons of all variables (p>0.05). There were no significant kinematic, kinetic or EMG differences between groups. For the WOMAC, the intergroup differences were significant in all three sections (pain: p=0.001, stiffness: p=0.008 and function: p=0.0005). In men with knee OA grade I or II, the stair decent is preserved in the sagittal plane, indicating that at these stages of the disease the functional adaptations are not expressed.

Isometric medial and lateral rotations torque steadiness in female workers with shoulder impingement

This study compared peak torque and torque steadiness during isometric lateral and medial rotations in workers with shoulder impingement syndrome (SIS) and those with no upper limb disorders. Twenty-nine female workers were evaluated. The SIS group consisted of 14 workers (36.57± 5.23 years) with unilateral SIS. The control group consisted of 15 healthy workers (35.53 ± 5.46 years). Three maximal voluntary isometric contractions (MVIC) of 5-s duration were performed to determine the peak torque, which was used to calculate the target torque (50% MVIC). For assessment of the torque steadiness 3 trials were performed at the target torque for 5 s each, with visual feedback. Standard deviation (SD) and coefficient of variati on (CV) were measured from the steadiness trials. Peak torque, SD and CV were not different (P > 0.05) between groups neither between affected and unaffected sides of the SIS group for both rotations. It was possible to suggest that torque steadin ess, during isometric medial and lateral rotations of the shoulder, is n ot altered in workers with SIS when compared to healthy workers, and that maintenance of regular work activities may play an important role in preservation of the steadiness in this populat ion.

Measuring postural control during mini-squat posture in men with early knee osteoarthritis

Studies have suggested a compromised postural control in individuals with knee osteoarthritis (OA) evidenced by larger and faster displacement of center of pressure (COP). However, quantification of postural control in the mini-squat posture performed by patients with early knee OA and its relation to muscle strength and self-reported symptoms have not been investigated. The main aim of this cross-sectional, observational, controlled study was to determine whether postural control in the mini-squat posture differs between individuals with early knee OA and a control group (CG) and verify the relation among knee extensor torque (KET) and self-reported physical function, stiffness and pain. Twenty four individuals with knee OA grades I and II (OAG) (mean age: 52.35±5.00) and twenty subjects without knee injuries (CG) (mean age: 51.40±8.07) participated in this study. Participants were assessed in postural control through a force plate (Bertec Mod. USA), which provided information about the anterior-posterior (AP) and medial-lateral (ML) COP displacement during the mini-squat, in isometric, concentric and eccentric knee extensor torque (KET) (90°/s) through an isokinetic dynamometer (BiodexMulti-Joint System3, Biodex Medical Incorporation, New York, NY, USA), and in self-reported symptoms through the WOMAC questionnaire. The main outcomes measured were the AP and ML COP amplitude and velocity of displacement; isometric, concentric, and eccentric KET and self-reported physical function, stiffness and pain. No significant differences were found between groups for postural control (p>0.05). Significant lower eccentric KET (p=0.01) and higher scores for the WOMAC subscales of pain (p=<0.001), stiffness (p=0.001) and physical function (p<0.001) were found for the OAG. Moderate and negative correlations were found between the AP COP amplitude of displacement and physical function (ρ=-0.40, p=0.02). Moderate and negative correlations were observed between the AP COP velocity of displacement and physical function (ρ=0.47, p=0.01) and stiffness (ρ=-0.45, p=0.02). The findings of the present study emphasize the importance of rehabilitation from the early degrees of knee OA to prevent postural instability and the need to include quadriceps muscle strengthening, especially by eccentric contractions. The relationship between the self-reported symptoms and a lower and slower COP displacement suggest that the postural control strategy during tasks with a semi-flexed knee should be further investigated.

Ankle strength impairments associated with knee osteoarthritis

Background Knee Osteoarthritis seems to negatively impact ankle biomechanics. However, the effect of knee osteoarthritis on ankle muscle strength has not been clearly established. This study aimed to evaluate the ankle strength of the plantar flexors and dorsiflexors of patients with knee osteoarthritis in different degrees of severity. Methods Thirty‐seven patients with knee osteoarthritis and 15 controls, subjected to clinical and radiographic analysis, were divided into three groups: control, mild, and moderate knee osteoarthritis. Participants answered a self‐reported questionnaire and accomplished a muscle torque assessment of the ankle using the Biodex dynamometer in isometric, concentric and eccentric modes. Findings The mild osteoarthritis group (peak torque = 26.85(SD 3.58)) was significantly weaker than the control (peak torque = 41.75(SD 4.42)) in concentric plantar flexion (P < 0.05). The control and mild osteoarthritis groups were not significantly different from the moderate osteoarthritis group (peak torque = 36.12(SD 4.61)) in concentric plantar flexion. There were no significant differences for dorsiflexion among the groups; however the control and moderate osteoarthritis groups presented large and medium standardized mean differences. The mild osteoarthritis group was significantly lower than the control and moderate osteoarthritis groups in the concentric plantar flexion by concentric dorsiflexion torque ratio. Interpretation Ankle function exhibited impairments in patients with knee osteoarthritis, especially in the plantar flexion torque, in which the mild osteoarthritis group was weaker than the control. Interestingly, patients with moderate knee osteoarthritis showed results similar to the control group in plantar flexion torque. The results raise the possibility of a compensatory mechanism of the plantar flexors developed by patients in more advanced degrees to balance other muscle failures. HighlightsKnee osteoarthritis subjects exhibit impairment in muscle strength of the ankle.Mild osteoarthritis subjects had lower plantar flexion torque than healthy subjects.Moderate osteoarthritis subjects had similar plantar flexion torque to healthy subjects.The results suggest a possible compensation mechanism carried out by the plantar flexors.

Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA). METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed. RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143). CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA.

FRI0580-HPR Correlation between Self-Reported Physical Function and Isokinetic Total Muscle Work in Early Degrees of Knee Osteoarthritis

Background Knee osteoarthritis (OA) is the most common chronic joint disease. Quadriceps is the muscle around the knee joint more affected by the disease, resulting in a reduction in functional muscle parameters. This may contribute to substantial functional deficits, however it is not clear if functional muscle parameters, like total muscle work, correlates to physical function in early degrees of knee osteoarthritis. Objectives The aim of this study was to evaluate the correlation between functional impairment and knee extensor total muscle work in men with Grades I or II knee OA. Methods Fourteen men with knee OA grade I or II (according to Kellgren & Lawrance criteria) participated in this study. The physical function section of the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) questionnaire was applied before the isokinetic evaluation. The concentric and eccentric knee extensor total muscle work were assessed using Biodex System 3 Pro isokinetic dynamometer, at a speed of 90°/s. Spearmans correlation coefficient was used to detect the relationship between the dependent variables (WOMAC questionnaire physical function section score) and the independent variables (average total muscle work). For all the statistical tests, the significance level was p<0.05. Results The data analysis revealed a moderate and negative correlation between self-reported physical function and eccentric extensor total muscle work (r= -0.8, p=0,001). The self-reported physical function presented no correlation with concentric extensor total muscle work (r= -0.5, p=0,07).These results indicate that the higher the knee extensor eccentric total muscle work, the lower the level of functional impairment self-reported by these individuals. Conclusions Our results indicate that correlation between eccentric knee extensor total muscle work and self-reported physical function are already present in individual with early degrees of knee OA. These results also indicate the lower the total work, the greater the functional deficit.Thus, physical therapy programs are indicated for these patients to improve physical function, especially in functional activities involving eccentric contraction of the quadriceps. References American College of Rheumatology Subcommittee on Osteoarthritis Guidelines.Recommendations for the medical management of osteoarthritis of the hip and knee: 2000 update. Arthritis Rheum 2000; 43:1905-15. Brandt KD, Dieppe PA, Eric R. Etiopathogenesis of osteoarthritis.Med Clin N Am 2009; 93: 1-24. Kellgren, J H, Lawrence, J S. Radiological assessment of osteo-arthrosis. Ann Rheum Dis, 1957; 16: 494-502. Weber JC, Lamb DR. Statistics and Research in Physical Education. Saint Luis: C.V; Mosby Company; 1970. Acknowledgements The Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP), São Paulo, Brazil for financial support (#2007/07200-4; #2011/06619-7). Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.3807