Falls Associated with Muscle Strength in Patients with Knee Osteoarthritis and Self-reported Knee Instability

Biomechanical adaptation to compensate balance recovery in people with knee osteoarthritis

BACKGROUND

Older adults with knee osteoarthritis are twice as likely to fall compared to healthy counterparts. Furthermore, in healthy older adults, greater trunk flexion is associated with increased falling. While spatio-temporal and strength measures have been connected to balance dysfunction in osteoarthritis, to date no studies have investigated compensation of both upper and lower body kinematics on balance recovery in this population.

METHODS

Forty-eight older people with knee osteoarthritis (age 71.02 ± 6.76 years, 54 % females, BMI 29.10 ± 4.58) and 15 asymptomatic controls (age 72.47 ± 4.81, 27 % females, BMI 26.17 ± 3.06) completed balance recovery during a simulated forwards fall. Ankle, knee, hip, trunk and head kinematics were collected and analysed using three trial types (no additional, cognitive dual-task and physical dual-task). Two-way MANCOVA were conducted to identify group differences in ankle, knee, hip, and trunk angle, and head position (control and knee osteoarthritis), trial differences (no additional, cognitive and physical dual-task) and group by trial differences.

FINDINGS

Postural differences in older adults with knee osteoarthritis included greater knee flexion (p = .02) and lower hip and trunk flexion (p < .01).

INTERPRETATION

Following a simulated fall, older adults with knee osteoarthritis showed greater knee flexion at first contact which might suggest inability to resist forwards motion of the body.The more extended hip in this group and the resulting compensation of the upper body posture may lead to no difference in number of steps taken when compared to controls.

A Comparative Study of Risk Factors for Falls in Total Hip and Knee Arthroplasty Patients and Community-Dwelling Older Adults

OBJECTIVES

Falls in older adults are a public health concern, yet little is known about falls in adults with hip or knee total joint arthroplasty (TJA) who may be at a higher risk than the general population. The study objectives were to compare the number of fallers and fear of falling in TJA patients to age and sex matched community controls, and determine whether the type of risk factors for falls reported in TJA differed from the community group.

METHODS

A cross sectional comparative study was conducted with patients waiting or recovering from TJA and age and sex matched comparison group of older adults residing in the community. Reported falls and risk factors for falling were compared to age and sex matched controls from the community. Fear of falling was measured using the Activities-specific Balance Confidence (ABC) Scale. Logistic regression was used to determine risk factors associated with falls in TJA and community participants.

RESULTS

Of the 198 TJA participants, 29% (n = 57) reported falls within the past 12 months compared to 24% (n = 24) of 100 participants in the control group (p = 0.36). Of those who fell, 25 (44%) were recurrent fallers in the TJA cohort compared with 6 (25%) in the community cohort. Eleven participants reported falls after TJA surgery. Fear of falling was greater in the TJA group (ABC score, mean ± SD: 67.1 ± 24.4) than in the community group (88.1 ± 14.9) (p < 0.001).

CONCLUSION

Although the number of participants who reported falls was comparable in both groups, the TJA group had more recurrent falls, different risk factors for falls, and more fear of falling. Fall prevention programs should be embedded in pre-operative programs for patients undergoing surgery for TJA.

Gait stability improves following unilateral total ankle arthroplasty

End-stage ankle arthritis is often treated surgically by total ankle arthroplasty (TAA) due to its potential to improve gait through increased joint range of motion and reduce pain. However, TAA's effect on gait stability is not well understood. This study explores the impact of TAA on gait stability, measured by Margin of Stability (MoS), in 148 patients with end-stage ankle arthritis. Kinematic data were collected pre-operatively, at 1-year post-op, and at 2-years post-op and the MoS was determined at heel strike and midstance for the anteroposterior (MoSAP) and mediolateral (MoSML) directions. A linear mixed effects model including gait speed as a factor was used to assess the effects of limb, session, and their interaction on outcome measures. A significant interaction (p < 0.002) between limb (surgical, nonsurgical) and session (pre-op, 1-year post-op, 2-years post-op) was identified for each MoS variable of interest. Cumulatively, our results suggest that the nonsurgical limb, MoSAP at heel strike and MoSML at midstance improved (increased) as time from surgery increased. These results suggest patients developed a compensatory movement pattern to navigate surgical limb single support. TAA reduces this compensation improving side-to-side symmetry, while not fully restoring symmetry by 2-years post-op. These results indicate that TAA could improve gait stability in patients with end-stage ankle arthritis, but further work is needed to understand the impact of TAA on altering fall risk.

Effects of Long-Term Walking Exercise on Structural Progression, Symptoms, and Extensor Muscle Strength in Patients With Mild or at High Risk of Knee Osteoarthritis: Data From the Osteoarthritis Initiative

OBJECTIVE

The aim of the study is to assess the relationship between walking exercise and medial joint space narrowing progression, symptoms, and knee extensor muscle strength in early knee osteoarthritis patients.

METHODS

This nested cohort study within the Osteoarthritis Initiative included participants aged 50 yrs and older with knee osteoarthritis (Kellgren-Lawrence grades 0-2). Walking exercisers were identified using a modified Historical Physical Activity Survey Instrument. Differences in medial joint space narrowing, Knee Injury and Osteoarthritis Outcome Score, and knee extensor muscle strength were evaluated through the three-way analysis of variance.

RESULTS

Among 896 participants, 83.4% reported walking exercise. Female walkers showed significant improvements in symptoms (Knee Injury and Osteoarthritis Outcome Score-pain: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-symptom: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-quality of life: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-function, sports, and recreational activities: P = 0.007). Similar results were observed in male walkers (Knee Injury and Osteoarthritis Outcome Score-pain: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-symptom: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-quality of life: P = 0.001; Knee Injury and Osteoarthritis Outcome Score-function, sports, and recreational activities: P = 0.009). Walkers showed significantly increased knee extensor muscle strength at 24 mos (female: P < 0.001; male: P = 0.003). Female nonwalkers had significantly decreased knee extensor muscle strength at 24 mos ( P < 0.001). Walkers showed significant improvement in medial joint space narrowing (odds ratio = 1.1, 95% confidence interval = 1.0-1.2) and Kellgren-Lawrence grade (OR = 1.0, 95% CI = 1.0-1.1) compared with nonwalkers.

CONCLUSIONS

Walking exercise prevents structural progression and improves symptoms. Meanwhile, the increased knee extensor muscle strength in all walkers further supports the validity of recommending walking exercises for early-stage knee osteoarthritis patients.

The test-retest reliability and concurrent validity of 360° turn test in patients with knee osteoarthritis

PURPOSE

The aim of this study is to determine whether the 360° turn test is a reliable and valid evaluator that can be used to assess dynamic balance in patients with early (radiographic grades I and II) and advanced (radiographic grades III and IV) knee osteoarthritis.

MATERIALS AND METHODS

This study is a methodological research. For the test time and step count of 360° turn test; test-retest reliability were determined by calculating the intraclass correlation coefficient and concurrent validity in patients with knee osteoarthritis was investigated by correlation with the timed up and go test time.

RESULTS

The final analysis was made on 117 participants. The intraclass correlation coefficient values for the test time and step count of 360° turn test in patients with early knee osteoarthritis are 0.931 and 0.902, respectively, while they are 0.923 and 0.943 in patients with advanced knee osteoarthritis. The Pearson correlation coefficients between the time and step count of 360° turn test and the test time of the timed up and go test in patients with early knee osteoarthritis, respectively; while they are 0.547 and 0.388, the correlation in patients with advanced knee osteoarthritis are 0.697 and 0.700, respectively (p < 0.01).

CONCLUSIONS

The 360° turn test is a evaluator that has excellent test-retest reliability and moderate to strong concurrent validity in patients with both early and advanced knee osteoarthritis and can be used in the assessment of dynamic balance in this population.

Postural stability and its relation to knee flexor/extensor strength ratio in women with mild to moderate unilateral knee osteoarthritis: a case-control study

PURPOSE/AIM

Knee muscles strength is an important factor influencing postural stability in patients with knee osteoarthritis (KOA). However, there is no evidence regarding the relationship between the knee flexor/extensor strength ratio, which is suggested to be a good indicator of knee stability, and postural stability. We aimed to investigate postural stability and its relation to knee flexor and extensor strength and strength symmetry in women with KOA.

MATERIALS AND METHODS

Thirty-five women with unilateral KOA and thirty-five asymptomatic women were assessed with the Prokin system to collect the following parameters during quiet standing with eyes-open and eyes-closed: ellipse area, perimeter, forward-backward standard deviation, mediolateral standard deviation, the average centre of pressure displacement on the x- and y-axises (COPX and COPY), and the limit of stability (LoS) score. Higher scores mean better balance for LoS and poorer balance for other parameters. Knee flexor and extensor strength were assessed bilaterally with the Lafayette hand-held dynamometer.

RESULTS

The COPX during standing with eyes-closed was higher in women with KOA than controls and the LoS score was lower (p < 0.05, Cohens'd = 0.72 and 0.65). Postural stability was correlated with knee muscles strength and the flexor/extensor strength ratios in both groups (r = between 0.395 and 0.456 for LoS, r = between -0.335 and -0.639 for the others, p < 0.05).

CONCLUSIONS

Women with KOA had poorer postural stability in the mediolateral direction during standing with eyes-closed and a worse LoS score than controls. Postural stability was related to knee flexor and extensor strength and the flexor/extensor strength ratio in women.

A controlled randomized trial with a 12-week follow-up investigating the effects of medium-frequency neuromuscular electrical stimulation on pain, VMO thickness, and functionality in patients with knee osteoarthritis

BACKGROUND

One of the major contributors to disability in Knee osteoarthritis (KOA) patients is weakness in the Quadriceps Femoris muscle. Neuromuscular electrical stimulation (NMES) has been used in rehabilitation for patients suffering from muscle weakness. Thus, the purpose of the study was to assess the effectiveness of NMES and exercise therapy, for improving pain, muscle weakness and function among patients with KOA.

METHODS

A randomized controlled trial was conducted with 75 female patients diagnosed with KOA. Participants were divided into three intervention groups: NMES-only, exercise therapy (Exs) alone, and a combination of NMES and exercise (NMES + Exs). All patients underwent 12 supervised treatment sessions, three times a week. Outcome measures included pain intensity measured by visual analog scale (VAS), knee flexion range of motion (FROM), thigh muscle girth (TG), thickness of the Vastus Medialis Oblique (VMO), timed up and go test (TUG), six-minute walk test (6MWT), and WOMAC scores. Statistical analyses (ANOVA and Kruskal-Wallis) methods were done to compare the amounts at the baseline, immediately after treatment and after 12 weeks.

RESULTS

The NMES group exhibited a significant reduction in pain at the 12-week follow-up compared to the other groups(p = 0.022). The NMES + Exs group showed better outcomes in terms of FROM, TG, and VMO thickness post-intervention (p < 0.0001, p < 0.004, p = 0.003, respectively) and at the 12-week follow-up (p < 0.0001, p < 0.0001, p < 0.0001, respectively). Additionally, NMES was superior in improving TUG and 6MWT post-intervention (p < 0.0001, p = 0.038, respectively) and during the follow-up assessments (p < 0.0001, p = 0.029, respectively). The NMES + Exs group achieved better WOMAC stiffness scores at both post-intervention and follow-up evaluations (p < 0.0001, p < 0.0001, respectively). Furthermore, at the 12-week follow-up, NMES + Exs group outperformed the others in WOMAC pain and function subscales (p = 0.003, p = 0.017, respectively), while the NMES group demonstrated better WOMAC total scores compared to the other groups (p = 0.007).

CONCLUSION

The combination of NMES and exercise seems to be an efficient approach for managing KOA, as it enhances knee flexion range and TG, increases VMO thickness, and improves WOMAC scores. On the other hand, NMES alone was found to be effective in improving the physical function of KOA patients.

TRIAL REGISTRATION

IRCT20101228005486N7 (06-02-2020).

Examination of the Increased Risk for Falls Among Individuals With Knee Osteoarthritis: A Canadian Longitudinal Study on Aging Population-Based Study

OBJECTIVE

To characterize the profile of individuals with and without knee osteoarthritis (OA) who fell, and to identify factors contributing to an individual with knee OA experiencing 1 or multiple injurious falls.

METHODS

Data are from the baseline and 3-year follow-up questionnaires of the Canadian Longitudinal Study on Aging, a population-based study of people ages 45-85 years at baseline. Analyses were limited to individuals either reporting knee OA or no arthritis at baseline (n = 21,710). Differences between falling patterns among those with and without knee OA were tested using chi-square tests and multivariable-adjusted logistic regression models. An ordinal logistic regression model examined predictors of experiencing 1 or more injurious falls among individuals with knee OA.

RESULTS

Among individuals reporting knee OA, 10% reported 1 or more injurious falls; 6% reported 1 fall, and 4% reported 2+ falls. Having knee OA significantly contributed to the risk of falling (odds ratio [OR] 1.33 [95% confidence interval (95% CI) 1.14-1.56]), and individuals with knee OA were more likely to report having a fall indoors while standing or walking. Among individuals with knee OA, reporting a previous fall (OR 1.75 [95% CI 1.22-2.52]), previous fracture (OR 1.42 [95% CI 1.12-1.80]), and having urinary incontinence (OR 1.38 [95% CI 1.01-1.88]) were significant predictors of falling.

CONCLUSION

Our findings support the idea that knee OA is an independent risk factor for falls. The circumstances in which falls occur differ from those for individuals without knee OA. The risk factors and environments that are associated with falling may provide opportunities for clinical intervention and fall prevention strategies.

The test-retest reliability and concurrent validity of performance-based task tests in patients with knee osteoarthritis

BACKGROUND

The measurement tool used for an accurate balance assessment should produce valid and reliable results in the population in which it is used.

OBJECTIVES

To examine whether two performance-based task tests are a reliable and valid measurement test to assess balance in patients with early and advanced knee osteoarthritis (KO).

DESIGN

Reliability and concurrent validity research.

METHOD

Test-retest reliability by calculating the intraclass correlation coefficient (ICC) between the first and second trial periods of performance-based task tests (Alternate Step Test & Pen Pick up Test); their correlations with the Timed Up and Go Test (TUGT) were calculated and their concurrent validity in balance assessment were examined.

RESULTS

A total of 100 patients (75% women, 25% men, mean 59 ± 10 years) with KO, 50 early (54 ± 7 years, 34 women, 16 men) and 50 advanced (64 ± 9 years, 41 women, 9 men), participated in the study. The ICC values for the Alternate Step Test (AST) and Pen Pick up Test (PPT) in patients with early KO are 0.881 (0.747-0.939, 95% confidence intervals) and 0.815 (0.689-0.892, 95% confidence intervals), respectively, while it is 0.852 (0.752-0.913, 95% confidence intervals) and 0.861 (0.756-0.922, 95% confidence intervals) in patients with advanced KO. Pearson correlation coefficient between AST & PPT times and TUGT time in patients with early and advanced KO was in the range of 0.535-0.746 (p < 0.01).

CONCLUSIONS

Both task tests are reliable and valid clinical measurement tests that can be used to assess balance in patients with both early and advanced KO.

Effect of Tai Chi on knee pain and muscle strength in middle-aged and older adults with knee osteoarthritis: a randomized controlled trial protocol

BACKGROUND

Knee osteoarthritis (KOA) is a common public health problem and a leading cause of long-term pain, decreased muscle strength, and even disability. Tai Chi has been proved effective and highly recommended for KOA management worldwide. However, little is known about its benefits on quadriceps strength which is closely associated with relieving knee pain. This trial is designed to evaluate the efficacy and safety of Tai Chi on knee pain and muscle strength in middle-aged and older adults with KOA.

METHODS

A total of 100 participants will be randomly divided into a Tai Chi group (TC group) (1x/week for 12 weeks) and a control group with a health education and stretching program (1x/week for 12 weeks) with a follow-up period of 6 weeks. The primary outcome is the change of Western Ontario and McMaster Universities (WOMAC) pain subscale at week 12 compared with baseline. Secondary outcomes include WOMAC stiffness and function subscales, data from isokinetic dynamometry, gait analysis with electromyography (EMG), and a 36-item short form health survey (SF-36). The daily dose of pain-relieving medication will also be recorded. All adverse effects will be assessed by the Treatment Emergent Symptom Scale (TESS).

DISCUSSION

We expect this randomized trial to evaluate the effectiveness of Tai Chi on relieving pain and increasing quadriceps strength in KOA patients. This protocol, if proven effective, will contribute to providing a promising alternative intervention for middle-aged and older adults with KOA.

TRIALS REGISTRATION NUMBER

This trial has been registered in the China Clinical Trials Registry (registration number: ChiCTR2300069339).

The Association Between Severity of Radiographic Knee OA and Recurrent Falls in Middle and Older Aged Adults: The Osteoarthritis Initiative

BACKGROUND

Knee osteoarthritis (KOA) is the most prevalent type of OA and a leading cause of disability in the United States. Falls are a major public health concern in older adults. Our aim was to examine how the severity of radiographic KOA affects recurrent falls in a cohort of middle-aged and older individuals enrolled in the Osteoarthritis Initiative.

METHODS

About 3 972 participants, mean age of 63 years, 58% female were included. Participants were divided into 5 mutually exclusive groups based on their worst Kellgren-Lawrence grade of radiographic KOA from annual x-rays from baseline to 36 months. Generalized estimating equations for repeated logistic regression were used to model the association between KOA severity and the likelihood of recurrent falls (≥2 falls/year) over 5 years of follow-up (>36 to 96 months).

RESULTS

Older adults (≥age 65) with KOA were at higher odds of recurrent falls in comparison to individuals without KOA in multivariate models (possible OA odds ratio [OR] = 2.22, 95% CI = 1.09-4.52; mild OA OR = 2.48, 95% CI = 1.34-4.62; unilateral moderate-severe OA OR = 2.84, 95% CI = 1.47-5.50; bilateral moderate-severe OA OR = 2.52, 95% CI = 1.13-5.62). Middle-aged adults (aged 45-64) with KOA did not have increased odds of recurrent falls in comparison to those without KOA except for possible KOA (OR = 1.86, 95% CI = 1.01-2.78; KOA severity × Age interaction = 0.025).

CONCLUSION

Older adults with radiographic evidence of KOA have an increased likelihood of experiencing recurrent falls in comparison to those without KOA independent of established risk factors. Our results suggest that fall prevention efforts should include older adults with all stages of KOA.

"I Remember the Fall": Memory of Falls in Older Adults

OBJECTIVES

While there is a large body of research on falls and their consequences in older adults, little is known about how older adults remember them. We addressed this gap by inviting older adults to remember falls and control memories.

METHODS

We analyzed specificity of memories and invited participants to rate emotional valence, mental time travel, visual imagery, importance, and rehearsal, as experienced during retrieval.

RESULTS

Although analysis demonstrated no significant differences between memories of falls and control memories regarding specificity, participants rated memories of falls as more negative than control memories. Furthermore, they rated memories of falls as triggering higher mental time travel, higher visual imagery, higher importance, and higher rehearsal than control memories.

CONCLUSIONS

The negative emotional valence of memories of falls, as well as their ability to trigger significant levels of mental time travel, visual imagery, importance, and rehearsal, demonstrate how these memories are different from other memories in older adults.

CLINICAL IMPLICATIONS

The findings demonstrate how falls can modulate memory of personal events in older adults.

Physiotherapeutic Strategies and Their Current Evidence for Canine Osteoarthritis

Osteoarthritis (OA) is a common and debilitating condition in domestic dogs. Alongside pharmaceutical interventions and weight loss, exercise and physiotherapy (PT) are important measures in maintaining patient mobility and quality of life. Physiotherapy for OA aims to reduce pain, optimize muscular function and maintain joint function. Physiotherapeutic plans typically include PT exercises combined with therapeutic modalities, lifestyle and environmental modifications to improve the patient's overall quality of life and function. Information on therapeutic clinical efficacy of physiotherapeutic measures for canine OA is still very limited. Thus, physiotherapeutic strategies are still primarily based on evidence extrapolated from human protocols tailored to people with OA. The authors propose a simple systematic PT approach for canine OA, prioritizing measures according to simplicity, cost effectiveness and practicality. This guide (the "Physiotherapy Pyramid") aims to provide a clear stratified approach to simplify decision making and planning for owners, veterinarians and veterinary physiotherapists, leading to more straightforward design and implementation of treatment plans. Measures are implemented starting at the base of the pyramid, subsequently progressing to the top, allowing effective and practical interventions to be prioritized. The levels of the pyramid are in ascending order: environmental modification, exercise plan, OA-specific home exercises and treatment by a veterinary physiotherapist.

Unjumbling Procedure in the Algorithmic Analysis of Biomechanical Torques Induced by Electrical Stimulation: Case Study of the Lower Limb

Functional Electrical Stimulation (FES) uses electrical pulses to cause muscles to contract synthetically. When muscles contract due to stimulation, torques are produced around joints attached to the muscle. It is important to understand torques being produced, for reasons such as safety and indirect fatigue measurement. Given the translatability of FES devices into the home for therapy, having ways to non-invasively measure muscle responses to stimulation is essential for understanding and diagnosing the biomechanical response of the human body. Here, we present data from a stimulation experiment examining knee joint torques (KJTs) arising when quadriceps are subjected to electrical stimulation. A novel algorithm for computing and summarizing KJT data into a series of simplified parameters was developed using MATLAB software. From this, we draw some conclusions about the effect of changing the stimulation duty cycle on the resultant KJT. We believe this method will provide researchers with a tool to measure torque in a semi-automated, convenient fashion.

Benefits and Mechanisms of Exercise Training for Knee Osteoarthritis

Knee osteoarthritis is a chronic degenerative disease. Cartilage and subchondral bone degeneration, as well as synovitis, are the main pathological changes associated with knee osteoarthritis. Mechanical overload, inflammation, metabolic factors, hormonal changes, and aging play a vital role in aggravating the progression of knee osteoarthritis. The main treatments for knee osteoarthritis include pharmacotherapy, physiotherapy, and surgery. However, pharmacotherapy has many side effects, and surgery is only suitable for patients with end-stage knee osteoarthritis. Exercise training, as a complementary and adjunctive physiotherapy, can prevent cartilage degeneration, inhibit inflammation, and prevent loss of the subchondral bone and metaphyseal bone trabeculae. Increasing evidence indicates that exercise training can improve pain, stiffness, joint dysfunction, and muscle weakness in patients with knee osteoarthritis. There are several exercise trainings options for the treatment of knee osteoarthritis, including aerobic exercise, strength training, neuromuscular exercise, balance training, proprioception training, aquatic exercise, and traditional exercise. For Knee osteoarthritis (KOA) experimental animals, those exercise trainings can reduce inflammation, delay cartilage and bone degeneration, change tendon, and muscle structure. In this review, we summarize the main symptoms of knee osteoarthritis, the mechanisms of exercise training, and the therapeutic effects of different exercise training methods on patients with knee osteoarthritis. We hope this review will allow patients in different situations to receive appropriate exercise therapy for knee osteoarthritis, and provide a reference for further research and clinical application of exercise training for knee osteoarthritis.

The Impact of Pain on Functionality, Postural Control and Fall Risk in Woman Aged 45 to 64 Years Old

BACKGROUND

Ageing in women is associated with chronic degenerative pain leading to a functional decrease and therefore increase fall risk. It is therefore essential to detect early functional decreases in the presence of pain related to osteoarthritis.

OBJECTIVE

This cross-sectional study aimed to assess the impact of pain on functionality, postural control and fall risk in women aged between 45 to 64 years old.

METHODS

Twenty-one (21) women aged 45 to 64 were evaluated by clinical and functional measures such as a pain questionnaire (Lequesne Index), functional tests (Stair Step Test, 5 times sit-to-stand, 6MWD, Timed-up and Go) and postural performance (under force platform). Women were classified into 2 groups from the Lequesne Pain Index (PI): low pain (score ≤ 9) and strong pain (score ≥ 10) for subsequent comparisons on functionality (physical and postural control performance).

RESULTS

A significant impact was observed between the pain index (strong PI) and 3 of the 4 functional tests carried out including Stair Step Test (p = 0.001; g = 1.44), walking distance (p = 0.003; g = 1.31) and Timed-up and Go (p = 0.04; g = -0.93). The group with a strong PI score reported further poor postural control under force platform compared to the weak pain group.

CONCLUSION

Pain and severity based on the PI index negatively modulate physical and postural control performance in women aged 45 to 64 years old.

Knee flexor and extensor torque ratio in elderly men and women with and without obesity: a cross-sectional study

BACKGROUND

With aging and obesity lower limb torque deteriorates. Importantly, the ratio between knee flexor (KF) and extensor (KE) torque is an indicator of joint stability.

AIMS

We compared KF torque and KF/KE ratio in older subjects of both sexes with obesity (OB) or without (NOB) obesity.

METHODS

The maximal torque during KE and KF isokinetic contractions were evaluated at: 60, 90, 150, 180 and 210 deg/s in 89 elderly (68 ± 5 years) subjects with NOB (BMI < 30 kg/m²) and OB (BMI ≥ 30 kg/m²). Values were normalised for body weight (BW) and leg lean mass (i.e., muscle quality).

RESULTS

At all speeds men had higher absolute KF values (P < 0.001). When values were normalised for BW, sex differences remain in favour of men (P < 0.001) with lower values in both groups with OB than NOB (P < 0.001). Muscle quality and KF/KE ratio were lower in OB than NOB (P < 0.001).

CONCLUSIONS

The KF torque and KF/KE ratio decline with aging and with OB. In all groups, the KF/KE ratio was below the joint stability threshold. Thus, exercise physiologists should include exercises designed to train both KE and KF in older subjects with OB.

Association between hip and knee osteoarthritis with falls: A systematic review and meta-analysis

OBJECTIVE

To examine the association between hip and knee osteoarthritis (OA) and falls. Potentially relevant articles that examine the association between hip, knee, radiological, and self-reported OA and falls were retrieved from PubMed, EMBASE, Scopus, and Web of Science up until March of 2020.

METHODS

The pooled risk ratios (RRs) as well as their related 95% confidence intervals (CIs) were calculated. Statistic and subgroup analyses were performed. A total of 21 studies involving 146 965 participants were included.

RESULTS

No association was found between hip OA and falls. The pooled RRs value suggested a higher prevalence of falls in knee OA patients (RR = 1.35, 95% CI: 1.20 to 1.51, P < .00001) and self-reported OA (RR = 1.33, 95% CI: 1.23 to 1.45, P < .00001) than in non-OA subjects. The pooled RR value suggested no difference between prevalence of falls in radiological OA patients compared to non-OA subjects (RR = 1.82, 95% CI: 0.89 to 3.73, P = .10). Both radiological and self-reported knee OA seem to be positively associated with falls, while no obvious association was found between hip OA and falls.

CONCLUSIONS

Therefore, knee OA is a risk factor for falls which should be closely monitored.

Memories of Falls: Resolved or Unresolved Memories?

Background: There is bourgeoning interest in how older adults remember their falls and research in this area has demonstrated how falls can reshape memory retrieval in older adults. We pursued this line of research by assessing whether older adults succeed in integrating memories of falls into their life story.Methods: We invited older adults to remember their falls and analyzed whether these memories were integrated or non-integrated.Results: Analysis demonstrated no significant differences between the number of integrated and non-integrated memories. Critically, however, higher anxiety and depression was observed in participants who produced non-integrated memories than in those who produced integrated ones.Discussion: The ability to integrate memories of falls in older adults is likely associated with anxiety and depression. Anxiety may result in avoidance of processing of the meaning of falls, and depression may hamper the ability to extract meaning from them, resulting in difficulties for older adults to integrate falls into their life story. Non-integrated memories of falls in older adults may be seen as unresolved memories and deserve special clinical attention.

Analysis of the Associations between Arthritis and Fall Histories in Korean Adults

(1) Background: the purpose of the present study was to analyze the associations between arthritis and fall histories in Korean adults. (2) Methods: data from the 2015 and 2017 Korean Community Health Survey were analyzed. In total, 322,962 participants aged ≥40 years were included. The participants were divided into two different groups. First, the participants were divided into the ‘arthritis (osteoarthritis or rheumatoid arthritis) for entire life’ and ‘nonarthritis for entire life (comparison I)’ groups. Subsequently, the participants were divided into the ‘current arthritis’ and ‘noncurrent arthritis (comparison II)’ groups. Afterwards, we analyzed the prevalence odds ratios (pORs) of the fall histories of the participants using a logistic regression analysis with the 95% confidence interval (CI). The variables of income, education level, region of residence, smoking status, alcohol consumption, obesity, subjective health status, stress level, physical activity, and sleep hours were adjusted for as covariates. (3) Results: both the arthritis for entire life and current arthritis groups had higher prevalence rates of falls than the comparison I and comparison II groups, respectively (each p < 0.001). The pORs of falling ≥1 time and ≥2 times per year in the arthritis for the entire life group were 1.42 (95% CI = 1.38–1.46) and 1.69 (95% CI = 1.62–1.76), respectively. The adjusted pORs for falling ≥1 time and ≥2 times per year in the current arthritis group were 1.35 (95% CI = 1.31–1.39) and 1.56 (95% CI = 1.50–1.63), respectively. (4) Conclusions: previous arthritis has a significant impact on the risk of falling.

Low Back Pain as a Risk Factor for Recurrent Falls in People With Knee Osteoarthritis

OBJECTIVE

Knee osteoarthritis (OA) has been suggested to increase the risk of falls. Low back pain (LBP) is a potential risk factor for falls in people with knee OA, but this issue has not been addressed adequately in previous studies. The objective of this study was to investigate the relationship between LBP and falls in people with knee OA in a 12-month period.

METHODS

Participants with knee OA (Kellgren/Lawrence [K/L] grade ≥1) completed questionnaires for LBP and falls that occurred in the preceding 12 months. Binary and ordinal logistic regression analyses were performed to assess the relationship between LBP or moderate-to-severe LBP (numeric rating scale ≥4 points) and any fall (≥1 fall) or recurrent falls (≥2 falls) after adjustment for age, sex, K/L grade, knee pain severity, and quadriceps strength. Sensitivity analyses were performed excluding people with sciatica, nonchronic LBP, K/L grade 1, and those receiving pain medications.

RESULTS

We included 189 participants (ages 61-90 years, 78.3% women) in this study. Of these participants, 41 (21.6%) reported falls in the preceding 12 months. People with any LBP (n = 101) and those with moderate-to-severe LBP (n = 45) had 2.7- and 3.7-times higher odds of recurrent falls, respectively. Sensitivity analyses revealed a strong correlation between moderate-to-severe LBP and recurrent falls.

CONCLUSION

Thorough investigation of LBP as a risk factor for recurrent falls in people with knee OA may provide a novel insight into the pathomechanics of recurrent falls in this population.

Physical and Psychological Factors Affecting Falls in Older Patients with Arthritis

As the population ages, falls are becoming one of the leading causes of morbidity and mortality. Joint disease (either osteoarthritis or rheumatoid arthritis) is a well-known predictor of falls, and these medical conditions increase in accordance with the aging population. This study aimed to describe individual, physical, and psychological characteristics between older adults with and without a fall history. Further, we aimed to identify statistically significant physical or psychological factors associated with falls by controlling individual variables. We analyzed data from the 2014 Survey of Living Conditions and Welfare Needs of Korean Older Adults. Adults aged 65 years or over with doctor-diagnosed joint disease were eligible. A total of 2707 women and 784 men (n = 3491) were enrolled. Of these, 1174 patients suffered a fall within a year (average number of falls = 2.4). We adopted individual variable-adjusted models and found that limited activities of daily living (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.04-1.87), fear of falling (OR 7.18, 95% CI 4.26-12.09), and depression (OR 1.28, 95% CI 1.09-1.50) significantly increased fall risks on logistic regression analysis. Our findings suggest that physical and psychological factors, especially the fear of falling, need to be addressed to prevent falls in elderly patients with arthritis.

Falls and fear of falling in older adults with total joint arthroplasty: a scoping review

BACKGROUND

Patients waiting or recovering from total joint arthroplasty (TJA) are at risk for falls which can lead to restriction of activity and negatively impact recovery. The objective of this scoping review is to critically appraise and synthesize the evidence in the reported number of falls, fear of falling, and risk factors associated with falls in older patients waiting for or recovering from TJA.

METHODS

Seven electronic databases were searched with no date limits and using language restriction (English). The inclusion criteria were 1) cohorts that included older adults 60+ years of age, 2) reported prevalence of falls, fear of falling, and/or risk factors for falls in patients who were waiting or recovering from TJA and 3) cross-sectional studies, cohort studies, and case control study designs. The quality assessment of selected articles was assessed using the SIGN Guidelines Checklist.

RESULTS

Of the 866 citations identified, 12 studies met the inclusion criteria and were reviewed. Prevalence of falls in pre-operative TJA patients and post-operative TJA patients ranged from 23 to 63%, and 13 to 42%, respectively. Of those five studies that examined fear of falling, pre-operative TJA patients reported greater fear of falling than post-operative patients. Modifiable risk factors for falls included fear of falling, joint range of motion, and depression.

CONCLUSIONS

An increased risk of falls in patients with TJA was reported both for patients waiting for and recovering from surgery. A number of modifiable risk factors were identified including fear of falling that could be targeted in fall prevention programs for TJA.

Oral administration of N-acetyl cysteine prevents osteoarthritis development and progression in a rat model

The number of osteoarthritis patients is increasing with the rise in the number of elderly people in developed countries. Osteoarthritis, which causes joint pain and deformity leading to loss of activities of daily living, is often treated surgically. Here we show that mechanical stress promotes accumulation of reactive oxygen species (ROS) in chondrocytes in vivo, resulting in chondrocyte apoptosis and leading to osteoarthritis development in a rat model. We demonstrate that mechanical stress induces ROS accumulation and inflammatory cytokine expression in cultured chondrocytes in vitro and that both are inhibited by treatment with the anti-oxidant N-acetyl cysteine (NAC). In vivo, osteoarthritis development in a rat osteoarthritis model was also significantly inhibited by oral administration of NAC. MMP13 expression and down-regulation of type II collagen in chondrocytes, both of which indicate osteoarthritis, as well as chondrocyte apoptosis in osteoarthritis rats were inhibited by NAC. Interestingly, osteoarthritis development in sham-operated control sides, likely due to disruption of normal weight-bearing activity on the control side, was also significantly inhibited by NAC. We conclude that osteoarthritis development in rats is significantly antagonized by oral NAC administration. Currently, no oral medication is available to prevent osteoarthritis development. Our work suggests that NAC may represent such a reagent and serve as osteoarthritis treatment.

Knee Osteoarthritis and the Risk of Medically Treated Injurious Falls Among Older Adults: A Community-Based US Cohort Study

OBJECTIVE

The risk of falls among adults with knee osteoarthritis (OA) has been documented, yet, to our knowledge no studies have examined knee OA and the risk of medically treated injurious falls (overall and by sex), which is an outcome of substantial clinical and public health relevance.

METHODS

Using data from the Health Aging and Body Composition Knee Osteoarthritis Substudy, a community-based study of white and African American older adults, we tested associations between knee OA status and the risk of injurious falls among 734 participants with a mean ± SD age of 74.7 ± 2.9 years. Knee radiographic OA (ROA) was defined as having a Kellgren-Lawrence grade of ≥2 in at least 1 knee. Knee symptomatic ROA (sROA) was defined as having both ROA and pain symptoms in the same knee. Injurious falls were defined using a validated diagnosis code algorithm from linked Medicare fee-for-service claims. Cox regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs).

RESULTS

The mean ± SD follow-up time was 6.59 ± 3.12 years. Of the 734 participants, 255 (34.7%) had an incident injurious fall over the entire study period. In the multivariate model, compared with those without ROA or pain, individuals with sROA (HR 1.09 [95% CI 0.73-1.65]) did not have a significantly increased risk of injurious falls. Compared with men without ROA or pain, men with sROA (HR 2.57 [95% CI 1.12-5.91]) had a significantly higher risk of injurious falls. No associations were found for women or by injurious fall type.

CONCLUSION

Knee sROA was independently associated with an increased risk of injurious falls in older men, but not in older women.

The effect of a portable electrical muscle stimulation device at home on muscle strength and activation patterns in locomotive syndrome patients: A randomized control trial

The aim of the present study was to quantify the effect of electrical muscle stimulation (EMS) intervention using a portable device on muscle strength and activation patterns in locomotive syndrome. Nineteen women were randomly assigned to the intervention group (n = 10; age = 71-82 years) and control group (n = 9; age = 70-84 years). Participants in the intervention group used a portable EMS device to stimulate the bilateral quadriceps muscles for 8 weeks (23 min/5 days/week). To understand the effects of EMS, the following measurements were made at baseline, 8 weeks, and 12 weeks: locomotive syndrome assessment score, knee extensor strength, vastus lateralis muscle activation patterns during a maximal isometric knee extension contraction using multi-channel surface electromyography, and muscle thickness. The locomotive syndrome assessment, muscle strength, muscle thickness, and muscle activity patterns in the intervention group were significantly different to control after 8 weeks (p < 0.05). However, these results were not sustained at 12 weeks. EMS increased locomotor assessment scores, which were accompanied by enhanced muscle strength, increased muscle thickness, and changes in muscle activation patterns in locomotive syndrome patients. These results suggest that EMS is potentially useful for improving muscle neural activation and force output in locomotive syndrome.

Self-reported Instability in Knee Osteoarthritis: A Scoping Review of Literature

BACKGROUND

Knee Osteoarthritis (OA) is a disabling musculoskeletal condition among the elderly. Self-reported instability is one of the impairments associated with osteoarthritis. A complete understanding of the self-reported instability in knee OA is essential, to identify the best strategies for overcoming this impairment. The focus of this scoping review is to provide an overview of evidence supported information about the prevalence and other associated features of selfreported instability in Knee OA. A broad search of the database PubMed with keywords such as knee osteoarthritis and instability resulted in 1075 articles. After title abstract and full-text screening, 19 relevant articles are described in the review. Overall, there is less amount of published literature on this topic. Studies reported prevalence rates of more than 60% for self-reported instability in knee osteoarthritis, which causes functional deterioration and high fear of falls. The most probable causative factors for self-reported instability in knee OA were altered sensory mechanisms and decreased muscle strength.

CONCLUSION

To conclude, self-reported knee instability in knee OA requires thorough evaluation and directed treatment with further studies providing rationalistic evidence-based management strategies. The current literature regarding self-reported knee instability is summarized, highlighting the research gaps.

Primary knee osteoarthritis increases the risk of falling

OBJECTIVES

The aim of this study was to investigate the effect of primary knee osteoarthritis on the risk of falling.

MATERIALS AND METHODS

One hundred participants (50 with knee osteoarthritis and 50 healthy controls) were included in this study. Primary knee osteoarthritis was diagnosed according to the American College of Rheumatology (ACR) criteria. Patients who were grade 2 or 3 by Kellgren-Lawrence criteria according to weight-bearing knee radiographs were included in this study. The risk of falling was evaluated by the interactive balance and coordination device both in the osteoarthritis and control groups. The functional status and pain were evaluated with respectively Lequesne Index and Visual Analogue Scale.

RESULTS

No statistically significant differences were found between the group of primary knee osteoarthritis and control in terms of age, BMI, and gender. The median falling index was 52 in the group with knee OA, whereas it was 31 in the control group. It was determined that primary knee osteoarthritis increased the risk of falling significantly and grade 3 primary knee osteoarthritis was statistically significantly higher than grade 2 (p < 0.001). The pain and functional status did not appear to be effective on the risk of falling in those patients (p > 0.05).

DISCUSSION

Falling is among the important causes of mortality and morbidity in advanced age. Therefore, assessment of risk factors for falling and the strategies to prevent it are important. Primary knee osteoarthritis is one of the risk factors associated with falling. Therefore, medical approaches, proprioception training, balance-gait training, muscle strengthening exercises, and arrangements to prevent domestic injurious falling should be planned to reduce the risk of falling in the presence of primary knee osteoarthritis.

Evidence-Based Cutoff Threshold Values from Receiver Operating Characteristic Curve Analysis for Knee Osteoarthritis in the 50-Year-Old Korean Population: Analysis of Big Data from the National Health Insurance Sharing Service

We aimed to investigate the characteristics of patients with osteoarthritis (OA), using the data of all Koreans registered in the National Health Insurance Sharing Service Database (NHISS DB), and to provide ideal alternative cutoff thresholds for alleviating OA symptoms. Patients with OA (codes M17 and M17.1–M17.9 in the Korean Standard Classification of Disease and Causes of Death) were analyzed using SAS software. Optimal cutoff thresholds were determined using receiver operating characteristic curve analysis. The 50-year age group was the most OA pathogenic group (among 40~70 years, n = 2088). All exercise types affected the change of body mass index (p < 0.05) and the sex difference in blood pressure (BP) (p < 0.01). All types of exercise positively affected the loss of waist circumference and the balance test (standing time on one leg in seconds) (p < 0.01). The cutoff threshold for the time in seconds from standing up from a chair to walking 3 m and returning to the same chair was 8.25 (80% sensitivity and 100% specificity). By using the exercise modalities, categorized multiple variables, and the cutoff threshold, an optimal alternative exercise program can be designed for alleviating OA symptoms in the 50-year age group.

Reliability and validity of the Turkish version of Activities-specific Balance Confidence scale in symptomatic knee osteoarthritis

BACKGROUND

Activities-specific Balance Confidence (ABC) scale is a well known tool to evaluate the functional balance. Balance impairment may accompany to knee osteoarthritis.

OBJECTIVE

The aim was to investigate the reliability and validity of the Turkish version of ABC in knee osteoarthritis.

METHODS

Forty-nine patients with knee osteoarthritis were included. All the participants were evaluated by ABC and Berg Balance Scale (BBS). Knee Injury and Osteoarthritis Outcome Score (KOOS) was used for the assessment of the knee related condition.

RESULTS

Mean age was 64.7 ± 9.2. Eighty-five percent was women. Mean ABC score was 53.5% and BBS score was 40. Interclass correlation coefficient was 0.95. There was a statistically significant positive correlation between the test-retest results (t= 1.90, p= 0.063). Correlation coefficient was high (p= 0.001, r= 0.953). Cronbach's alpha was 0.97. There was a significant positive correlation between ABC-T and BBS, the symptoms, daily living activities and quality of life subscales of KOOS (r= 0.555, p< 0.001; r= 0.424, r= 0.379, r= 0.621, p< 0.01). ABC-T correlated negatively with the radiological severity (r = -0.316, p< 0.05).

CONCLUSIONS

ABC-T is a reproducible test with excellent internal consistency and construct validity in knee osteoarthritis. Balance confidence was moderate and related with the symptoms, daily living activities, disease severity and quality of life.

The effect of primary total knee arthroplasty on the incidence of falls and balance-related functions in patients with osteoarthritis

Knee osteoarthritis (OA) is an established risk factor for falls and balance impairment. This study investigated the incidence of falls, balance-related outcomes and risk factors for falls before and after primary total knee arthroplasty (TKA). Three hundred seventy-six OA patients scheduled to undergo TKA were included. Falls data within the preoperative, first postoperative and second postoperative years were collected, balance-related functions were assessed using the Assessment of Quality of Life (AQoL), WOMAC, Falls Efficacy Scale International (FES-I), Activities-specific Balance Confidence (ABC), knee extension strength, Berg Balance Scale (BBS) and Timed Up and Go (TUG) before surgery and 1 and 2 years after surgery. Compared with preoperative values, the incidence of falls significantly decreased (14.89%, 6.23% and 3.14% within the preoperative, first postoperative and second postoperative years, respectively) and the AQoL, WOMAC, FES-I, ABC, knee extension strength, BBS and TUG significantly improved after TKA. Logistic regression analysis revealed that Kellgren-Lawrence grade ≥ 3 of the contralateral knee was an independent risk factor for falls before and after TKA. Conclusively, primary TKA is associated with a reduced incidence of falls and improved balance-related functions, and the contralateral knee should be considered in the design of fall-prevention strategies in patients with OA.

Preoperative methylprednisolone does not reduce loss of knee-extension strength after total knee arthroplastyA randomized, double-blind, placebo-controlled trial of 61 patients

Background and purpose - Patients undergoing total knee arthroplasty (TKA) face challenges related to postoperative reduction in knee-extension strength. We evaluated whether inhibition of the inflammatory response by a single preoperative dose of methylprednisolone (MP) reduces the pronounced loss of knee-extension strength at discharge after fast-track TKA. Patients and methods - 70 patients undergoing elective unilateral TKA were randomized (1:1) to preoperative intravenous (IV) MP 125 mg (group MP) or isotonic saline IV (group C). All procedures were performed under spinal anesthesia without tourniquet, and with a standardized multimodal analgesic regime. The primary outcome was change in knee-extension strength from baseline to 48 hours postoperatively. Secondary outcomes were knee joint circumference, functional performance using the Timed Up and Go (TUG) test, pain during the aforementioned tests, rescue analgesic requirements, and plasma C-reactive protein (CRP) changes. Results - 61 patients completed the follow-up. The loss in quadriceps muscle strength was similar between groups; group MP 1.04 (0.22-1.91) Nm/kg (-89%) vs. group C 1.02 (0.22-1.57) Nm/kg (-88%). Also between-group differences were similar for knee circumference, TUG test, and pain scores. MP reduced the inflammatory response (CRP) at 24 hours postoperatively; group MP 33 (IQR 21-50) mg/L vs. group C 72 (IQR 58-92) mg/L (p < 0.001), and 48 hours postoperatively; group MP 83 (IQR 56-125) mg/L vs. group C 192 (IQR 147-265) mg/L (p < 0.001), respectively. Interpretation - Preoperative systemic administration of MP 125 mg did not reduce the pronounced loss of knee-extension strength or other functional outcomes at discharge after fast-track TKA despite a reduced systemic inflammatory response.

Tibiofemoral Osteoarthritis and Varus-Valgus Laxity

The purpose of this study was to systematically review and synthesize the literature measuring varus-valgus laxity in individuals with tibiofemoral osteoarthritis (OA). Specifically, we aimed to identify varus-valgus laxity differences between persons with OA and controls, by radiographic disease severity, by frontal plane knee alignment, and by sex. We also aimed to identify if there was a relationship between varus-valgus laxity and clinical performance and self-reported function. We systematically searched for peer-reviewed original research articles in PubMed, Scopus, and CINAHL to identify all existing literature regarding knee OA and objective measurement of varus-valgus laxity in vivo. Forty articles were identified that met the inclusion criteria and data were extracted. Varus-valgus laxity was significantly greater in individuals with OA compared with controls in a majority of studies, while no study found laxity to be significantly greater in controls. Varus-valgus laxity of the knee was reported in persons with OA and varying degrees of frontal plane alignment, disease severity, clinical performance, and self-reported function but no consensus finding could be identified. Females with knee OA appear to have more varus-valgus laxity than males. Meta-analysis was not possible due to the heterogeneity of the subject populations and differences in laxity measurement devices, applied loading, and laxity definitions. Increased varus-valgus laxity is a characteristic of knee joints with OA. Large variances exist in reported varus-valgus laxity and may be due to differences in measurement devices. Prospective studies on joint laxity are needed to identify if increased varus-valgus laxity is a causative factor in OA incidence and progression.

Effects of attentional focus on walking stability in elderly

INTRODUCTION

Balance performance in the elderly is related to psychological factors such as attentional focus. We investigated the effects of internal vs. external focus of attention and fall history on walking stability in healthy older adults.

METHOD

Walking stability of twenty-eight healthy older adults was assessed by applying random unilateral decelerations on a split-belt treadmill and analysing the resulting balance recovery movements. The internal focus instruction was: concentrate on the movement of your legs, whereas the external focus instruction was: concentrate on the movement of the treadmill. In both conditions participants were asked to look ahead at a screen. Outcome measures were coefficient of variation of step length and step width, and characteristics of the centre of mass velocity time-series as analysed using statistical parametric mapping. Fall history was assessed using a questionnaire.

RESULTS

After each perturbation participants required two to three strides to regain a normal gait pattern, as determined by the centre of mass velocity response. No effects were found of internal and external focus of attention instructions and fall history on any of the outcome measures.

DISCUSSION

We conclude that, compared to an internal focus of attention instruction, external focus to the walking surface does not lead to improved balance recovery responses to gait perturbations in the elderly.

Influence of focus of attention, reinvestment and fall history on elderly gait stability

Falls represent a substantial risk in the elderly. Previous studies have found that a focus on the outcome or effect of the movement (external focus of attention) leads to improved balance performance, whereas a focus on the movement execution itself (internal focus of attention) impairs balance performance in elderly. A shift toward more conscious, explicit forms of motor control occurs when existing declarative knowledge is recruited in motor control, a phenomenon called reinvestment. We investigated the effects of attentional focus and reinvestment on gait stability in elderly fallers and nonfallers. Full body kinematics was collected from twenty-eight healthy older adults walking on a treadmill, while focus of attention was manipulated through instruction. Participants also filled out the Movement Specific Reinvestment Scale (MSRS) and the Falls Efficacy Scale International (FES-I), and provided details about their fall history. Coefficients of Variation (CV) of spatiotemporal gait parameters and Local Divergence Exponents (LDE) were calculated as measures of gait variability and gait stability, respectively. Larger stance time CV and LDE (decreased gait stability) were found for fallers compared to nonfallers. No significant effect of attentional focus was found for the gait parameters, and no significant relation between MSRS score (reinvestment) and fall history was found. We conclude that external attention to the walking surface does not lead to improved gait stability in elderly. Potential benefits of an external focus of attention might not apply to gait, because walking movements are not geared toward achieving a distinct environmental effect.

Are people following hip and knee arthroplasty at greater risk of experiencing a fall and fracture? Data from the Osteoarthritis Initiative

INTRODUCTION

Falls are a major challenge for older people and are a significant source of mortality and morbidity. There has been uncertainty as to whether people with total hip (THA) or knee (TKA) arthroplasty have a greater risk of falls and associated fractures. This analysis was to explore this question with a large community dataset.

MATERIALS AND METHODS

Data from all people enroled onto the US Osteoarthritis Initiative programme who had undergone a THA (n = 104) or TKA (n = 165), within a 12-month period, were compared to those who had not undergone an arthroplasty (n = 4631). Data were collected on: the number of participants who reported a fall within a 12-month period; the frequency of falls in this period; and whether a fracture was sustained during this period. Odd ratios were calculated for the probability of experiencing a fall or fracture between the groups.

RESULTS

There was no statistical difference in falls between people following THA (OR 0.90; 95 % CI 0.58-1.41) or TKA (OR 0.95; 0.67-1.35) compared to a non-arthroplasty cohort. Whilst there was no statistical difference in fracture risk between people following TKA compared to non-arthroplasty individuals (OR 1.25; 95 % CI 0.57-2.70), those who underwent THA had a 65 % lower chance of experiencing a fracture in the initial 12 post-operative months compared to the non-THA cohort (OR 0.35; 95 % CI 0.19-0.65; p < 0.01).

CONCLUSIONS

There appears a lower chance of experiencing a fracture for people following THA compared to those who have not.

Is there an increased risk of falls and fractures in people with early diagnosed hip and knee osteoarthritis? Data from the Osteoarthritis Initiative

AIMS

To assess the probability of individuals with early-diagnosed hip or knee osteoarthritis experiencing a fall and/or fracture compared to a cohort without osteoarthritis.

METHODS

Data were analyzed from the Osteoarthritis Initiative dataset. We identified all people who were diagnosed with hip or knee osteoarthritis within a 12 month period, compared to those without osteoarthritis. We determined whether there was a difference in the occurrence of falls, with or without consequential fractures, between people newly diagnosed with hip or knee osteoarthritis compared to those who had not, using odd ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Five hundred and fifty-two individuals with hip osteoarthritis were compared to 4244 individuals without hip osteoarthritis; 1350 individuals with knee osteoarthritis were compared to 3445 individuals without knee osteoarthritis. People with knee osteoarthritis had a 54% greater chance of experiencing a fall compared to those without (OR: 1.54; 95% CI: 1.35-1.77). People with hip osteoarthritis had a 52% greater chance of experiencing a fall compared to those without hip osteoarthritis (OR: 1.52; 95% CI: 1.26-1.84). People with knee and hip osteoarthritis demonstrated over an 80% greater chance of experiencing a fracture in the first 12 months of their diagnosis compared to those without hip or knee osteoarthritis (total knee arthroplasty: OR 1.81; total hip arthroplasty: OR 1.84).

CONCLUSIONS

There is an increased risk of falls and fractures in early-diagnosed knee and hip osteoarthritis compared to those without osteoarthritis. International guidelines on the management of hip and knee osteoarthritis should consider the management of falls risk.

Effects of noxious stimulation to the back or calf muscles on gait stability

Gait stability is the ability to deal with small perturbations that naturally occur during walking. Changes in motor control caused by pain could affect this ability. This study investigated whether nociceptive stimulation (hypertonic saline injection) in a low back (LBP) or calf (CalfP) muscle affects gait stability. Sixteen participants walked on a treadmill at 0.94ms(-1) and 1.67ms(-1), while thorax kinematics were recorded using 3D-motion capture. From 110 strides, stability (local divergence exponent, LDE), stride-to-stride variability and root mean squares (RMS) of thorax linear velocities were calculated along the three movement axes. At 0.94ms(-1), independent of movement axes, gait stability was lower (higher LDE) and stride-to-stride variability was higher, during LBP and CalfP than no pain. This was more pronounced during CalfP, likely explained by the biomechanical function of calf muscles in gait, as supported by greater mediolateral RMS and stance time asymmetry than in LBP and no pain. At 1.67ms(-1), independent of movement axes, gait stability was greater and stride-to-stride variability was smaller with LBP than no pain and CalfP, whereas CalfP was not different from no pain. Opposite effects of LBP on gait stability between speeds suggests a more protective strategy at the faster speed. Although mediolateral RMS was greater and participants had more asymmetric stance times with CalfP than LBP and no pain, limited effect of CalfP at the faster speed could relate to greater kinematic constraints and smaller effects of calf muscle activity on propulsion at this speed. In conclusion, pain effects on gait stability depend on pain location and walking speed.