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

Concentrating to avoid falling: interaction between peripheral sensory and central attentional demands during a postural stability limit task in sedentary seniors

Evidence suggests falls and postural instabilities among seniors are attributed to a decline in both the processing of afferent signals (e.g., proprioceptive, vestibular) and attentional resources. We investigated the interaction between the non-visual and attentional demands of postural control in sedentary seniors. Old and young adults performed a postural stability limit task involving a maximal voluntary leaning movement with and without vision as well as a cognitive-attentional subtraction task. These tasks were performed alone (single-task) or simultaneously (dual-task) to vary the sensory-attentional demands. The functional limits of stability were quantified as the maximum center of pressure excursion during voluntary leaning. Seniors showed significantly smaller limits of postural stability compared to young adults in all sensory-attentional conditions. However, surprisingly, both groups of subjects reduced their stability limits by a similar amount when vision was removed. Furthermore, they similarly decreased their anterior-posterior stability limits when concurrently performing the postural and the cognitive-attentional tasks with vision. The overall average cognitive performance of young adults was higher than seniors and was only slightly affected during dual-tasking. In contrast, older adults markedly degraded their cognitive performance from the single- to the dual-task situations, especially when vision was unavailable. Thus, their dual-task costs were higher than those of young adults and increased in the eyes-closed condition, when postural control relied more heavily on non-visual sensory signals. Our findings provide the first evidence that as posture approaches its stability limits, sedentary seniors allot increasingly large cognitive attentional resources to process critical sensory inputs.

Analysis of Postural Control in Patients Diagnosed with Unilateral Knee Osteoarthrosis and Its Relationship with the Risk of Falls

Introduction

Knee osteoarthrosis, whether subtle or marked, appears to alter the stability and performance of the knee joint in activities of daily living that prevent the maintenance of bipedal posture. However, there is still a gap in the literature as to how knee osteoarthritis can affect static balance.

Objective

To analyze the performance of postural control in elderly diagnosed with unilateral knee osteoarthrosis.

Materials and Methods

40 elderly people of both sexes participated in this study, divided into two groups containing 20 elderly each. Group 1 (G1) consists of elderly patients who have received a diagnosis of unilateral knee osteoarthritis. Despite undergoing conservative treatment, their condition has shown insufficient improvement, leading to a clinical recommendation for total knee arthroplasty (TKA). The G2 group was made up of 20 elderly with an average age of 71.09 years, considered active, who do not have a diagnosis of osteoarthritis in the knee joint and practice physical activity. With the aid of a Baroscan pressure platform, the center of pressure (COP) displacement in the anteroposterior (COPAP) direction and mediolateral direction (COPML) and the area of center of pressure displacement were evaluated during bipedal postural control with eyes open and eyes closed.

Results

During postural control with eyes open and eyes closed, the G1 group showed greater displacement of the COP in the anteroposterior direction-COPAP (p = 0.007)-and mediolateral direction-COPML (p = 0.033)-when compared to the G2 group. As for the area of displacement of the COP, group G1 presented a larger area of displacement (p = 0.002) than group G2 during bipedal postural control with open eyes. For the condition with eyes closed, both groups showed similar behaviors, which resulted in no present statistically significant differences.

Conclusion

The results suggest that unilateral knee osteoarthritis influences bipedal postural control and activities of daily living that require this static balance, since information from the somatosensory system is reduced, resulting in stability of tasks that require body control and promoting the risk of falls. From a clinical perspective, the results suggest that the assessment of bipedal postural control can assist orthopedic physicians in assessing joint stability in patients with unilateral knee osteoarthrosis.

Comparison of the asymmetries in muscle mass, biomechanical property and muscle activation asymmetry of quadriceps femoris between patients with unilateral and bilateral knee osteoarthritis

Background: More and more attention has been paid to the research of muscle mass and muscle quality of quadriceps femoris (QF) in knee osteoarthritis (KOA). This study aimed to explore the asymmetric changes of muscle mass, biomechanical property and muscle activation in the inter-limbs QF of KOA patients, and tried to provide a novel insight for the evaluation, prevention and treatment of KOA. Methods: A total of 56 Participants with unilateral or bilateral KOA were included in this study: 30 patients with unilateral pain and 26 patients with bilateral pain were assigned to the bilateral group (BG) and unilateral group (UG), respectively. The symptom severity of bilateral lower limbs was evaluated by visual analogue scale, and the relatively serious leg (RSL) and relatively moderate leg (RML) were classified. The thickness of rectus femoris (RF), vastus intermedius (VI), vastus medialis (VM) and vastus lateralis (VL) were measured by ultrasound. The Shear wave elastography (SWE) techniqie was used to measure the shear modulus of RF, VM and VL. Surface electromyography (sEMG) was used to assess the root mean square (RMS) of the RF, VM, and VL during straight leg raising in a sitting position and squatting task. We calculated the asymmetry indexes of inter-limbs for the corresponding indices of the measured muscles. Result: Thickness of RF, VI and VL of RSL was lower than those on RML (p < 0.05), and thickness of VM was lower more significant (p < 0.01). Thickness of RF, VI and VL of RSL was also lower than those of RML in BG (p < 0.05), however, there was no significant difference in VM thickness (p > 0.05). There were no significant difference in Asymmetry indexes of all measured muscle thickness between the two groups (p > 0.05). The Shear modulus of RF, VM, and VL in the RML of UG and BG was higher than those in the RSL (p < 0.05). In sitting and straight leg raising task, the RMS of RF, VM and VL in RML were higher than those in RSL, UG and BG both showed this trend (p < 0.05). About squatting task, in UG, the RMS of the three muscles in RML of patients were also higher than those in the RSL (p < 0.05). However, the difference was not significant in BG (p > 0.05). In the straight leg raising task, the asymmetry indexes of RMS in RF, VM, and VL of both the two groups were positively correlated with VAS scores (p < 0.05). Conclusion: The muscle thickness, shear modulus and muscle activation electromyography of QF in RML were higher than those of RSL in unilateral KOA patients. The VM of RML in bilateral KOA patients may show muscle thickness degeneration earlier, which is closer to the VM of RSL. The shear modulus of RF, VM, and VL were higher on the RML side during the single-leg task, but there may be passive compensation for muscle activation in both lower limbs during the bipedal task. In conclusion, there is a general asymmetry of QF muscle mass, biomechanics Characteristic and performance in patients with KOA, which may provide new ideas for the assessment, treatment and rehabilitation of the disease.

Early Osteoarthritis Questionnaire (EOAQ): a tool to assess knee osteoarthritis at initial stage

Background

Early stage of osteoarthritis (OA) is characterized by joint stiffness and pain as well as by subclinical structural changes that may affect cartilage, synovium, and bone. At the moment, the lack of a validated definition of early osteoarthritis (EOA) does not allow to make an early diagnosis and adopt a therapeutic strategy to slow disease progression. Also, no questionnaires are available to evaluate the early stage, and therefore this remains an unmet need.

Objective

Therefore, the purpose of the technical experts panel (TEP) of 'International Symposium of intra-articular treatment' (ISIAT) was to create a specific questionnaire to evaluate and monitor the follow-up and clinical progress of patients affected by early knee OA.

Design

The items for the Early Osteoarthritis Questionnaire (EOAQ) were identified according to the following steps: items generation, items reduction, and pre-test submission.

Methods

During the first step, literature has been reviewed and a comprehensive list of items about pain and function in knee EOA was drafted. Then, during the ISIAT (5th edition 2019), the draft has been discussed by the board, which reformulated, deleted, or subdivided some of the items. After the ISIAT symposium, the draft was submitted to 24 subjects affected by knee OA. A score based on the importance and the frequency was created and the items with a score ⩾0.75 were selected. After intermediate evaluation made by a sample of patients, the second and final version of the questionnaire EOAQ was submitted to the whole board for final analysis and acceptance in a second meeting (29 January 2021).

Results

After an exhaustive elaboration, the final version of the questionnaire contains two domains (Clinical Features and Patients Reported Outcome) with respectively 2 and 9 questions, for a total of 11 questions. Questions mainly explored the fields of early symptoms and patients reported outcomes. Marginally, the need of the symptoms treatment and the use of painkillers were investigated.

Conclusions

Adoption of diagnostic criteria of early OA is strongly encouraged and a specific questionnaire for the whole management of the clinical features and patients' outcome might really improve the evolution of OA in the early stages of the disease, when the treatment is expected to be more effective.

Neuromuscular joint function in knee osteoarthritis: A systematic review and meta-analysis

BACKGROUND

Neuromuscular alterations are common in people with knee osteoarthritis (KOA). A comprehensive understanding of these alterations is important to enable targeted rehabilitation strategies.

OBJECTIVES

This systematic review and meta-analysis aimed to comprehensively understand the neuromuscular alterations around the knee joint in people with KOA.

METHODS

Moderate- and high-quality studies based on a modified version of the Downs and Black checklist, comparing neuromuscular function of peri‑articular muscles between people with KOA and controls were retrieved from five databases from inception to October 2020. Outcomes included normalized isokinetic strength, muscle size, voluntary activation, cortical and spinal-reflex excitability, and torque-related outcomes. Data were pooled according to structural KOA severity with sensitivity analysis based on sex. Evidence levels are presented in evidence gap maps.

RESULTS

A total of 7 high-quality and 22 moderate-quality studies were retained (1146 people with KOA and 1353 age- and sex-matched controls). Studies demonstrated quadriceps and hamstring strength deficits and increased hamstring-to-quadriceps strength ratios across KOA severities. Women presented lower quadriceps strength at early KOA (very limited evidence) and lower voluntary activation at end stage KOA (very limited evidence) as compared with controls, whereas men did not (moderate evidence). People with KOA also demonstrated lower quadriceps force control ability with no change in rapid force production (very limited evidence). Voluntary activation deficits for quadriceps were evident (moderate evidence), with no change in quadriceps cortical excitability (very limited evidence) or soleus spinal reflexes (very limited evidence). No muscle size change was demonstrated except for the vastus medialis (limited evidence). Evidence gaps were found for neural and torque-related measures and differences in hamstring, gastrocnemius, soleus, and popliteus.

CONCLUSIONS

Neuromuscular deficits are evident across different structural KOA severities and are seen in muscle strength, voluntary activation, muscle size, and force control ability. Women may exhibit these alterations to a greater extent than men.

PROSPERO REGISTRATION NUMBER

CRD42019160845.

Asymmetries and relationships between muscle strength, proprioception, biomechanics, and postural stability in patients with unilateral knee osteoarthritis

Background: The pathological mechanism of knee osteoarthritis (KOA) is unknown. KOA degeneration may be associated with changes in muscle strength, proprioception, biomechanics, and postural stability.

Objective: This study aimed to assess asymmetries in muscle strength, proprioception, biomechanics, and postural stability of bilateral lower limbs in patients with unilateral KOA and healthy controls and analyze correlations between KOA and these parameters.

Methods: A total of 50 patients with unilateral KOA (age range: 50-70) and 50 healthy subjects were recruited as study participants (age range: 50-70). Muscle strength, proprioception, femorotibial angle (FTA), femoral condylar–tibial plateau angle (FCTP), average trajectory error (ATE), and center of pressure (COP) sways areas were accessed in study participants, and the correlation between these variables was investigated.

Results: In patients with unilateral KOA, lower limb muscle strength was significantly lower on the symptomatic side than on the asymptomatic side (p < 0.01), while the proprioception (degree error), FTA, FCTP, and ATE were substantially higher compared to the asymptomatic side (p < 0.01). However, no significant difference was observed in the healthy controls (p > 0.05). Patients with unilateral KOA had lower muscle strength than healthy controls (p < 0.05), but their proprioception (degree error: the difference between the target and reproduction angles), ATE, and COP sway areas were higher (p < 0.05). Muscle strength was found to be negatively correlated with ATE and COP sways areas (p < 0.05), whereas proprioception (degree error) was positively correlated with ATE and COP sways areas (p < 0.05) in all study participants. However, no correlation was found between FTA, FCTP, and ATE, COP sways areas in patients with unilateral KOA (p > 0.05).

Conclusion: In patients with unilateral KOA, muscle strength, proprioception, biomechanics, and postural stability of bilateral limbs are asymmetrical in unilateral KOA patients. Muscle strength, proprioception, and postural stability are significantly associated variables, and changes in these variables should be considered in KOA prevention and rehabilitation.

Hyperalgesia affects muscle activity and knee range of motion during a single-limb mini squat in individuals with knee osteoarthritis: a cross-sectional study

BACKGROUND

The effect of hyperalgesia on functionality remains uncertain for individuals with knee osteoarthritis (KOA). This study aimed examine the clinical measures and hyperalgesia's effect on muscle activity, knee range of motion (ROM) and postural control during the single-leg mini squat (SLMS) in individuals with KOA, determining the correlation between variables.

METHODS

In this cross-sectional study, 60 individuals, 30 healthy (HG, 57.4 ± 6.86 years), and 30 with mild to moderate KOA (KOAG, 59.4 ± 5.46 years) were evaluated by the visual analog scale (VAS), Western Ontario and McMaster Universities Index (WOMAC), and the pressure pain threshold (PPT) in subcutaneous, myotomal, and sclerotomal structures. Muscle activity, knee ROM and postural control were assessed during a SLMS. The analyses were performed in the two phases of the SLMS. Phase 1 - during descending movement (eccentric contraction), Phase 2 - during ascending movement (concentric contraction). Analysis of covariance was applied for each variable separately, using weight as a co-variable. We used Spearman's test for determining the correlation.

RESULTS

There was no difference between groups for age, height, and postural control (p > 0.059), but KOAG presented the highest values for VAS and WOMAC (p = 0.000). In addition, EMG activity was higher in KOAG for gastrocnemius medialis and tibialis anterior muscles during phase 1 (p < 0.027), and for gastrocnemius medialis and gluteus medius muscles during phase 2 (p < 0.007), and reduced values for PPT and knee ROM (p = 0.000). Also, the correlations between PPT with muscle activity and postural control were moderate (rho< 0.482), while strong relationships were observed between some PPT points with VAS and WOMAC (rho> 0.507).

CONCLUSION

Hyperalgesia affects the functionality during a single-limb mini squat. There is an important correlation between hyperalgesia and muscle activity, postural control, and clinical measures in individuals with KOA.

Assessment of the musculoskeletal performance with squat tests and performance-oriented measurements in older adults

BACKGROUND

Balance and mobility impairments, declined musculoskeletal strength and performance, limited range of motion, and poor flexibility are fairly common among older adults.

OBJECTIVES

To determine the lower extremity muscle force and to verify the correlation with the gait characteristics and balance in community dwelling older adults.

METHODS

Seventy-five adults with a mean age of 75.07 ± 6.28 years were included in the study. All participants were evaluated with the following tests: half squat (HS), decline squat (DS), foot print analysis (step length, step wide, stride length, walking velocity and cadence) and Tinetti Performance Oriented Mobility Assessment (POMA).

RESULTS

HS and DS test scores were significantly correlated with Tinetti Balance and Gait Assessment scores and gait characteristics, except step wide (p< 0.01). The results of this study showed that the participants who have higher scores in the squat tests, showed higher scores in terms of POMA (p< 0.01).

CONCLUSION

Appropriate and direct assessment of lower limb power and performance in balance and gait tests should be done to identify functioning of the older adults. Half and eccentric decline squat tests used in this study were useful, cheap and easy. The squat tests can be used to determine the relationship between balance and gait characteristics, in addition to predicting the musculoskeletal performance in older adults.

Biomechanical analysis during single-leg squat in individuals with knee osteoarthritis

Backgroud: The single-leg squat (SLS) is a functional task to evaluate the abnormal movement patterns and potential neuromuscular deficits in the lower limbs. Still, it is unknown if SLS could provide information to older adults with knee osteoarthritis (KOA). The study's objective was to analyze the EMG pattern, kinematics, and postural control in individuals with and without KOA during SLS.

METHODS

Participated in this study, 60 volunteers of both sexes, 30 had KOA (allocated into the KOA group - KOAG), and 30 were healthy (allocated into the Healthy Group - HG) performing the single-leg squat. Surface electromyography (EMG) was assessed for the gastrocnemius medialis (GM), biceps femoris (BF), gluteus medius (GLM), rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), and tibialis anterior (TA) in two phases (downward - P1 and upward - P2). The kinematic data was evaluated using an electrogoniometer. The center of pressure (CoP) was obtained using data collected from a force plate.

RESULTS

EMG activity was increased for GM and TA muscles during the P1 of the movement and the GM and GLM muscles during P2 of the movement. The angular displacement of the KOAG was lower when compared with the HG. There was no statistical difference for the co-contraction and postural control data.

CONCLUSIONS

The SLS analysis showed that EMG activity of the muscles TA, GM, and GLM was increased in the KOAG, but this pattern could be affected by fear of movement leading to reduced knee angular displacement.

Proprioception deficiency in articular cartilage lesions of the knee

Purpose

The purpose of this study is to investigate the proprioceptive function of patients with isolated articular cartilage lesions of the knee as compared to normal controls.

Methods

The Cartilage group consisted of eight subjects with radiologically and arthroscopically confirmed, isolated, unilateral, articular cartilage lesions of the knee (Outerbridge grade III or IV). They were compared to 50 normal controls. Knee proprioception was assessed by dynamic postural stabilometry using the Biodex Balance SD System. Patient-reported outcome measures (PROMs) were used to evaluate all subjects.

Results

Proprioception of the injured knee of the Cartilage group was significantly poorer compared to that of the control group (p < 0.001). A significant proprioceptive deficit also was observed when the uninjured knees of the Cartilage group were compared to those in the Control group (p = 0.003). There was no significant proprioceptive difference between the injured and the contra-lateral uninjured knee of the Cartilage group (p = 0.116). A significant correlation was found between the proprioception measurements of the injured and uninjured knee of the Cartilage group (r = 0.76, p = 0.030). A significant difference was observed in all PROMs (p < 0.001) between the Cartilage and Control groups.

Conclusions

Patients with isolated articular cartilage lesions of the knee had a significant proprioceptive deficit as compared to normal controls. The deficiency was profound and even affected the proprioceptive function of the contra-lateral uninjured knee. This study has shown that articular cartilage lesions have a major influence on knee proprioception. However, it remains uncertain as to whether a proprioceptive deficit leads to osteoarthritis or is a consequence of it.

Age-related changes in leg proprioception: implications for postural control

In addition to being a prerequisite for many activities of daily living, the ability to maintain steady upright standing is a relevant model to study sensorimotor integrative function. Upright standing requires managing multimodal sensory inputs to produce finely tuned motor output that can be adjusted to accommodate changes in standing conditions and environment. The sensory information used for postural control mainly arises from the vestibular system of the inner ear, vision, and proprioception. Proprioception (sense of body position and movement) encompasses signals from mechanoreceptors (proprioceptors) located in muscles, tendons, and joint capsules. There is general agreement that proprioception signals from leg muscles provide the primary source of information for postural control. This is because of their exquisite sensitivity to detect body sway during unperturbed upright standing that mainly results from variations in leg muscle length induced by rotations around the ankle joint. However, aging is associated with alterations of muscle spindles and their neural pathways, which induce a decrease in the sensitivity, acuity, and integration of the proprioceptive signal. These alterations promote changes in postural control that reduce its efficiency and thereby may have deleterious consequences for the functional independence of an individual. This narrative review provides an overview of how aging alters the proprioceptive signal from the legs and presents compelling evidence that these changes modify the neural control of upright standing.

Increased postural stiffness during challenging postural tasks in patients with knee osteoarthritis with high pain sensitization

BACKGROUND

Postural stability is affected in knee osteoarthritis patients who present with pain but the link to pain sensitization is unclear.

METHODS

Patients with knee osteoarthritis completed the Knee Injury and Osteoarthritis Outcome Score and pressure pain thresholds were assessed bilaterally at the knee, lower leg and forearm prior to standing quietly (1 min) on a force platform in four conditions: Firm surface with open eyes, firm surface with closed eyes, soft surface with open eyes, and soft surface with closed eyes. Pain intensity during standing was assessed via numerical rating scale. Postural stability was assessed by the range, velocity, and standard deviation of the Center of Pressure (CoP) extracted from the force platform. The means of three repeated measures per standing condition were analysed. High-sensitization and low-sensitization groups were defined based on bilateral pressure pain thresholds from leg and arm.

FINDINGS

Fifty-six patients were included. Compared with the low-sensitization group, the high-sensitization group demonstrated 1) smaller pressure pain thresholds at the knee (P < 0.05) although the Knee Injury and Osteoarthritis Outcome Score and pain intensity were not significantly different between groups, and 2) smaller range of the CoP in the anterior-posterior direction during the soft surface with closed eyes condition (P < 0.05).

INTERPRETATION

Smaller CoP range suggest that patients with more widespread pain sensitivity have increased postural stiffness compared with the low-sensitization group. The greater stiffness found in high-sensitization patients under sensory restrictions (closed eyes and reduced proprioception) might relate to restricted integration of sensory information due to widespread pain sensitization.

The relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy

BACKGROUND

Patellar tendinopathy is a common condition resulting in persistent pain, frequently reported during physical activity. The relationship between dynamic postural stability and pain in these individuals is unclear and how it may affect postural stability.

RESEARCH QUESTION

Is there a relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy?

METHODS

Twenty-two recreationally active individuals with patellar tendinopathy participated. Participants performed a two-legged jump and landed on a single test-limb on a force platform. They completed 100 mm visual analogue scales (VAS) before and after landing trials. Anterior-posterior (APSI), medial-lateral (MLSI), vertical (VSI), and composite (DPSI) stability indices were calculated from ground reaction force data. The relationship between stability indices and VAS for pain as well as pain change scores were assessed via non-parametric Spearman's rho (ρ) rank correlations (p≤.05).

RESULTS

Baseline pain was not significantly correlated with any stability indices. Post-landing pain was significantly correlated with MLSI (ρ = 0.540, p = 0.004) while, VSI (ρ = 0.353, p = 0.053) and DPSI (ρ = 0.347, p = 0.057) had moderate, yet insignificant correlations. Pain change scores demonstrated a large correlation with MLSI (ρ = 0.598, p = 0.002).

SIGNIFICANCE

As pain increased in individuals with patellar tendinopathy, dynamic postural stability indices values increased, indicating more difficulty transitioning from a dynamic to static state. Although balance deficits are not typically associated with patellar tendinopathy, it appears pain and dynamic postural stability may be related in these individuals.