Incorporating interactive workshops into bedside teaching: completion of a multi-modal rheumatology rotation significantly increases internal medicine residents' competency and comfort with comprehensive knee examinations.

BACKGROUND: Studies have elucidated the lack of competency in musculoskeletal (MSK) examination skills amongst trainees. Various modalities have been studied, however, there remains a dearth of literature regarding the effectiveness of bedside teaching versus dedicated workshops. Our aim was to determine if incorporating a workshop into a rheumatology rotation would be effective in increasing medicine residents' competency and comfort with knee examinations when compared to the rotation alone. METHODS: Over 16 months, rotators were randomized to workshop plus rotation versus rotation alone. Participants were tested on their knee examination skills using an objective structured clinical examination (OSCE). Surveys were administered assessing to what degree the rotation was beneficial. Comfort and helpfulness were measured using a 5-point Likert scale. Paired and independent samples t-tests were used for comparisons. RESULTS: Fifty-seven residents participated. For both groups, there were improvements between pre- and post-OSCE scores (workshop p < 0.001, no workshop p = 0.003), and levels of comfort with examination (workshop p < 0.001, no workshop p < 0.001). When comparing groups, there were differences favoring the workshop in post-OSCE score (p = < 0.001), mean change in OSCE score (p < 0.001) and mean change in comfort with knee examination (p = 0.025). CONCLUSION: An elective in rheumatology augmented residents' MSK competency and comfort. Incorporation of a workshop further increased knowledge, skills and comfort with diagnosis and treatment. Current educational research focuses on alternatives to traditional methods. This study provides evidence that a multi-modal approach, combining traditional bedside and interactive models, is of benefit.

Health Disparities Among Hispanics With Rheumatoid Arthritis: Delay in Presentation to Rheumatologists Contributes to Later Diagnosis and Treatment.

OBJECTIVE: The aim of this study was to evaluate referral and treatment delays by ethnicity/race in patients with rheumatoid arthritis (RA) treated at an academic rheumatology center. METHODS: We reviewed the medical records of all RA patients evaluated at an outpatient clinic between 2011 and 2016 to identify newly diagnosed and naive-to-treatment patients. We determined the durations between symptom onset and first rheumatology visit and time to initiate treatment. Data extraction included referral source, demographics, treatment, and laboratory tests. Routine use of a multidimensional health assessment questionnaire allowed us to calculate baseline RAPID3 (routine assessment of patient index data 3) scores. Comparisons between self-reported ethnicity/race groups were performed. We used logistic regression models to analyze associations between baseline variables and early referral. RESULTS: Data from 152 disease-modifying antirheumatic drug-naive RA patients were included in the study; 35% were white, 37% black, 20% Hispanic, and 8% other. The range in median time to first rheumatology visit was 6 to 8 months for all patient groups, except Hispanic. This group had a median time of 22.7 months (p = 0.01). The referral pattern was considerably variable between-groups; 40% of Hispanic patients were self-referred (p = 0.01). There were no statistically significant between-group differences for time to treatment initiation according to ethnicity/race. RAPID3 scores (p = 0.04) and erythrocyte sedimentation rates (p = 0.01) were significantly higher in the black and Hispanic groups. A high C-reactive protein value at baseline was associated with earlier referral. CONCLUSIONS: There is significant delay in initial presentation to a rheumatologist that was associated with a higher disease severity at presentation, especially for Hispanic patients.

Discordance of global assessment by patients and physicians is higher in osteoarthritis than in rheumatoid arthritis: a cross-sectional study from routine care.

The study compares patient-physician discordance in global assessment in patients with osteoarthritis (OA) versus patients with rheumatoid arthritis (RA) seen in routine care. This is a cross-sectional study conducted at an academic rheumatology center at which all patients are asked to complete a Multi-Dimensional Health Assessment Questionnaire (MDHAQ), which includes a patient global assessment (PATGL). Rheumatologists are encouraged to complete a physician questionnaire, which includes a physician global assessment (DOCGL). Patients with either OA or RA were identified using ICD9 codes and classified as positive discordance (PATGL-DOCGL ≥ 2), negative discordance (PATGL-DOCGL≤ - 2), and concordance (absolute difference between the two assessments < 2). Discordance was assessed by diagnosis. Agreement between patient and physician global assessments was evaluated using intraclass correlations. Logistic regression was performed to identify explanatory variables for positive discordance. The analysis included 243 OA and 216 RA patients. Mean PATGL was higher in OA versus RA (5.4 versus 4.2, p = 0.005), while mean DOCGL was similar (4.0 versus 3.8, p = 0.23) leading to a higher patient-physician discordance in OA (1.35 versus 0.43, p < 0.001). Positive discordance occurred in 34% of OA versus 18% of RA patients (p < 0.001). Intraclass correlation coefficients were 0.43 in OA versus 0.60 in RA patients. In logistic regressions, pain was the only statistically significant explanatory variable for discordance in both OA (OR 1.34, 95% CI 1.12-1.78) and RA (OR 1.47 95% CI 1.04-2.07). Patients with OA are more likely to be discordant with their rheumatologists than patients with RA because of a higher PATGL. Similarly to RA, the most important explanatory variable for discordance was higher pain.

Somatosensation in OA: exploring the relationships of pain sensitization, vibratory perception and spontaneous pain.

BACKGROUND: Pain in osteoarthritis (OA) remains poorly understood. Different types of somatosensory alterations exist in OA including hyperesthesia and increased sensitivity to painful stimuli as well as those of decreased sensitivity to cutaneous stimuli including vibratory perception threshold. The relationship between these different somatosensory measures has not been previously evaluated in OA. In this observational study, we evaluated relationships between vibratory perception (VPT), pressure pain detection thresholds (PPT), allodynia and subjective pain in knee OA. METHODS: Forty-two persons with moderate to severe knee OA and 12 controls without OA were evaluated. VPT was measured using a biothesiometer. Allodynia was measured by application of a 60 g Von Frey monofilament repeatedly to predetermined sites. PPTs were measured using a pressure algometer. RESULTS: Increased vibratory acuity was associated with lower PPTs and presence of allodynia. Allodynia was more common in OA than controls (54.8% vs 16.6%, p = 0.024 in the ipsilateral knee, and 42.9% vs 0%, p = 0.005 in the contralateral knee). OA participants with allodynia had lower PPTs than those without allodynia. In those with OA, spontaneous knee pain was associated with lower PPTs and with allodynia. CONCLUSION: This study confirms the presence of somatosensory alterations in OA. Sensory alterations (vibratory perception) were shown to be related to nociceptive alterations (sensitization) in OA, showing a general increased sensitivity to cutaneous mechanical stimulation. Understanding these relationships is an important step in delineating the complicated pathophysiology of pain processing in OA.

Morning Versus Evening Bright Light Treatment at Home to Improve Function and Pain Sensitivity for Women with Fibromyalgia: A Pilot Study.

Objective: To test the feasibility, acceptability, and effects of a home-based morning versus evening bright light treatment on function and pain sensitivity in women with fibromyalgia. Design: A single blind randomized study with two treatment arms: 6 days of a 1 hour morning light treatment or 6 days of a 1 hour evening light treatment. Function, pain sensitivity, and circadian timing were assessed before and after treatment. Setting: Participants slept at home, except for two nights in Sleep Center. Participants: Ten women meeting the American College of Rheumatology's diagnostic criteria for fibromyalgia, including normal blood test results. Methods: Self-reported function was assessed with the Fibromyalgia Impact Questionnaire (FIQ). Pain sensitivity was assessed using a heat stimulus that gave measures of threshold and tolerance. Circadian timing was assessed with the dim light melatonin onset. Results: Both morning and evening light treatments led to improvements in function and pain sensitivity. However, only the morning light treatment led to a clinically meaningful improvement in function (>14% reduction from baseline FIQ) and morning light significantly increased pain threshold more than evening light ( P < 0.05). Phase advances in circadian timing were associated with an increase in pain tolerance (r = 0.67, P < 0.05). Conclusions: Bright light treatment appears to be a feasible and acceptable adjunctive treatment to women with fibromyalgia. Those who undergo morning light treatment may show improvements in function and pain sensitivity. Advances in circadian timing may be one mechanism by which morning light improves pain sensitivity. Findings can inform the design of a randomized controlled trial.

Vibratory sense deficits in patients with symptomatic femoroacetabular impingement.

OBJECTIVE: Sensory deficits, measured through vibratory perception threshold (VPT), have been recognized in hip and knee osteoarthritis (OA), but have not been evaluated in femoroacetabular impingement (FAI), thought to be a pre-OA condition. This study aimed to assess VPT in symptomatic FAI pre- and 6-months post-arthroscopy vs. METHODS: FAI patients and controls were assessed for VPT at the first metatarsophalangeal joint. Pain was assessed using a visual analog pain scale. FAI participants were evaluated again 6-months after surgery for FAI. Differences between groups and pre- and post- surgery were evaluated with independent and paired sample t-tests, respectively. Secondary analysis was performed using repeated-measures ANOVA to evaluate the effect of pain and time since surgery on VPT pre- and post-operatively. RESULTS: No differences in age and BMI were seen between groups (p>0.05). Reduced VPT (higher value is worse) was evident in the pre- (8.0±3.9V, t=2.81, p=0.009) and post-operative (6.8±2.8V, t=2.34, p=0.027) patients compared to controls (4.7±1.3V). After hip arthroscopy, there was a trend toward improved VPT (t=1.97, p=0.068). Preoperative and 6-months postoperative pain and time since surgery were not found to influence VPT (F-ratio⋝0.00, p⋝0.427). CONCLUSION: Sensory deficits were observed in FAI patients both before and 6-months after hip arthroscopy.

The Feasibility of Using Augmented Auditory Feedback From a Pressure Detecting Insole to Reduce the Knee Adduction Moment: A Proof of Concept Study.

The objective of this work was to conduct a proof of concept study utilizing auditory feedback from a pressure-detecting shoe insole to shift plantar pressure medially in order to reduce the knee adduction moment (KAM). When compared with normal walking, 32 healthy subjects significantly reduced their peak KAM using feedback (p < 0.001). When compared with medial thrust gait, an established gait modification, walking with pressure-based feedback was equally effective at reducing the peak KAM, yet it successfully mitigated other potentially detrimental gait measures such as the peak knee flexion moment (KFM), knee internal rotation moment (KIrM), and a reduction in speed.

Improvement in knee loading after use of specialized footwear for knee osteoarthritis: results of a six-month pilot investigation.

OBJECTIVE: Biomechanical interventions for knee osteoarthritis (OA) aim to improve pain and retard disease progression by decreasing knee loading. This study was undertaken to evaluate the effects of 6 months of use of flat, flexible footwear (the mobility shoe) on knee loading in OA. METHODS: Subjects with knee OA underwent baseline gait analyses under conditions of walking in their own shoes, walking in mobility shoes, and walking barefoot. Thereafter, subjects wore the mobility shoes at least 6 hours per day for 6 days per week. Gait evaluations were repeated at 6, 12, and 24 weeks. An intent-to-treat analysis was performed to assess the longitudinal effects on knee loading with the shoe intervention. RESULTS: Compared to knee loading at baseline with the participants' own shoes, there was an 18% reduction in the knee adduction moment (KAM) by 24 weeks with the mobility shoes (P < 0.001) and no significant differences in the KAM by 24 weeks between mobility shoe and barefoot walking (P = 0.192). Over the 6 months of followup, participants also experienced an 11% reduction in the KAM when walking in their own shoes (P = 0.002) and a 10% reduction in the KAM when walking barefoot (P = 0.002 for the whole followup), as compared to these values at baseline under the same conditions. CONCLUSION: This study suggests that use of flat, flexible footwear results in significant reductions in knee loading in subjects with OA. By 24 weeks, there is evidence of a gait adaptation with sustained load reduction even when the mobility shoes are removed, suggesting that footwear may serve as a biomechanical training device to achieve beneficial alterations in gait mechanics for knee OA.

The relationship of vibratory perception to dynamic joint loading, radiographic severity, and pain in knee osteoarthritis.

OBJECTIVE: Patients with knee osteoarthritis (OA) have been shown to have somatosensory deficits of the lower extremity. This study was designed to assess the association of these deficits with dynamic joint loading and their relationship to the structural and symptomatic severity of knee OA. METHODS: Subjects with symptomatic knee OA underwent evaluation of the vibratory perception threshold (VPT) using a biothesiometer at 5 sites at the lower extremity. Dynamic joint loading was assessed through gait analyses. Knee pain was evaluated using a visual analog scale score for pain based on the Western Ontario and McMaster Universities OA Index. Radiographic severity of knee OA was assessed using the Kellgren/Lawrence (K/L) grading scale on radiographs obtained with the knee in a standing position. RESULTS: Dynamic knee joint loading was directly associated with the VPT at the metatarsophalangeal (MTP) joint (Spearman's rho=0.384, P=0.033), indicating that the worse the vibratory sense, the higher the knee load during gait. The K/L severity grade was directly associated with the VPT at the MTP joint and lateral femoral condyle, after adjustment for age, sex, body mass index, and knee pain. After adjustment for confounders, there were no significant associations observed between the VPT and pain at any of the sites tested. CONCLUSION: These findings demonstrate an association between greater somatosensory deficits and higher dynamic loads in OA. They also demonstrate structural consequences associated with somatosensory deficits in OA, since the extent of sensory loss directly correlated with the radiographic severity of knee OA. However, there was no relationship observed between vibratory sense and symptomatic knee OA pain.

Changes in medial-to-lateral knee joint loading patterns assessed by Dual-Energy X-ray Absorptiometry following supervised neuromuscular exercise therapy and patient education in patients with knee osteoarthritis: an exploratory cohort study.

BACKGROUND: The mechanisms underlying pain reductions following exercise therapy in patients with knee osteoarthritis (OA) are poorly understood. One mechanism could be changes in mechanical knee joint loading. OBJECTIVE: To investigate if a neuromuscular exercise therapy and patient education intervention could alter knee joint loading assessed by Dual-Energy X-ray Absorptiometry (DXA) in people with knee OA. METHODS: Participants with symptomatic knee OA were evaluated before and 26 weeks after an 8-week supervised neuromuscular exercise therapy and patient education intervention (Good Life with OsteoArthritis in Denmark). DXA scans were used to estimate the medial-to-lateral tibial plateau bone mineral density (BMD) ratio. The Knee Injury and Osteoarthritis Outcome Score was used to assess improvements in knee pain, symptoms, physical function, and knee-related quality of life. Changes in physical function were assessed with the 30-second chair stand test and the 40-meter fast paced walk test. RESULTS: Of 42 participants recruited, 30 (21 females, mean age 64 ± 7.9 years) had full data available. Medial-to-lateral tibial BMD ratio increased non-significantly by 0.02 (95% CI -0.01 to 0.06) (indicating higher medial load) from baseline to 26-weeks follow-up. Participants had statistically significant improvements of 21% in pain, 17% in symptoms, 14% in ADL, 17% in knee-related quality of life, 13% in chair stand ability, and 6% in walking speed. CONCLUSIONS: In this exploratory cohort study, following an 8-weeks supervised exercise therapy and patient education intervention, the medial-to-lateral tibial BMD ratio did not seem to change.

Asymmetric loading and bone mineral density at the asymptomatic knees of patients with unilateral hip osteoarthritis.

OBJECTIVE: In patients with unilateral end-stage hip osteoarthritis (OA), the contralateral knee is known to be at greater risk for end-stage knee OA compared to the ipsilateral (i.e., same-side) knee. The contralateral knee is known to have increased dynamic joint loads compared to the ipsilateral knee. The present study was undertaken to examine patients who had unilateral hip OA but who did not have symptoms of knee OA, in order to detect early asymmetries in knee loading. METHODS: Data on 62 patients with unilateral hip OA were evaluated. Patients underwent gait analyses of dynamic knee loads as well as dual x-ray absorptiometry for determination of bone mineral density (BMD) in both knees. Differences between knees were compared. RESULTS: Peak dynamic knee loads were significantly higher at the contralateral knee compared to the ipsilateral knee (mean ± SD 2.46 ± 0.71 percent of body weight × height versus 2.23 ± 0.81 percent of body weight × height; P = 0.029). Similarly, medial compartment tibial BMD was significantly higher in the contralateral knee compared to the ipsilateral knee (mean ± SD 0.897 ± 0.208 gm/cm(2) versus 0.854 ± 0.206 gm/cm(2); P = 0.033). Interestingly, there was a direct correlation between the contralateral:ipsilateral dynamic knee load and contralateral:ipsilateral medial compartment tibial BMD (ρ = 0.287, P = 0.036). CONCLUSION: The risk of developing progressive symptomatic OA in contralateral knees is higher compared to the risk in ipsilateral knees in patients with unilateral hip OA. The present study demonstrates that loading and structural asymmetries appear early in the disease course, while the knees are still asymptomatic. These early biomechanical asymmetries may have corresponding long-term consequences, providing further evidence for the potential role of loading in OA onset and progression.

Lower limb osteoarthritis: biomechanical alterations and implications for therapy.

PURPOSE OF REVIEW: To review the role of biomechanics in the pathogenesis of lower-extremity osteoarthritis and recent advances in biomechanically active intervention strategies for osteoarthritis. RECENT FINDINGS: The conventional approach to treating knee osteoarthritis with analgesics and physical therapy has not been shown to alter the natural history of the disease, suggesting that novel strategies are necessary. Progression of lower-extremity osteoarthritis is mediated by aberrant biomechanics, which can be assessed using gait analyses and validated markers of dynamic knee loading such as the peak adduction moment (AddM) and adduction angular impulse (AddImp). Recognition of the mechanical component of osteoarthritis progression has led to intervention strategies that seek to reduce functional loads at the knee, and thereby, potentially, to palliate pain and retard disease progression. SUMMARY: Biomechanically active interventions have been demonstrated to reduce dynamic loading of the knees in patients with osteoarthritis, and are potentially promising strategies to treat symptoms as well as to alter disease progression in osteoarthritis.

The biomechanics of osteoarthritis: implications for therapy.

The pathophysiology of osteoarthritis (OA) has been extensively studied. However, the basic approach to therapy, which consists of pain relief and maintenance of function, has not changed for decades. At present, there are no nonsurgical methods that clearly interfere with the natural history of OA or provide prolonged pain palliation. Much of OA disease progression is mediated by aberrant biomechanical forces or through pathologic responses to those forces. As understanding of these mechanisms improves, novel therapeutic approaches are being studied that may provide prolonged reductions in loading of OA joints. These new therapies may ultimately be shown to retard disease progression and palliate pain. This article reviews some of these strategies.

Unsupervised gait retraining using a wireless pressure-detecting shoe insole.

BACKGROUND: The knee adduction moment (KAM) is a surrogate measure of mediolateral distribution of loads across the knee joint and is correlated with progression and severity of knee osteoarthritis (OA). Existing biomechanical approaches for unloading the arthritic medial knee compartment vary in their effectiveness in reducing KAM. This study employed a completely wireless, pressure-detecting shoe insole capable of generating auditory feedback via a smartphone. RESEARCH QUESTION: To investigate whether auditory cues from a smartphone can prompt subjects to adjust their gait pattern and reduce KAM. METHODS: Nineteen healthy subjects underwent gait training inside the lab (Phase 1) and received auditory cues during mid- and terminal stance to medialize their foot COP (center-of-pressure). This initial training period was continued unsupervised while walking around campus (Phase 2). RESULTS: After Phase 1, subjects reduced their KAM by 20.6% (p = 0. 001), a finding similar to a previous study that used a wired, lab-based insole system. After further unsupervised training outside the lab during Phase 2, subjects were able to execute the newly learned gait pattern without auditory feedback still showing a KAM reduction of 17.2% (p < 0.001). Although, speed at Phase 2 was lower than at baseline (p = 0.013), this reduction had little effect on KAM (r = 0.297, p = 0.216). In addition, the adduction angular impulse was reduced (p = 0.001), despite the slower speed. SIGNIFICANCE: Together, these results suggest that the wireless insole is a promising tool for gait retraining to lower the KAM and will be implemented in a home-based clinical trial of gait retraining for subjects with knee OA.

Hip joint moments in symptomatic vs. asymptomatic people with mild radiographic hip osteoarthritis.

Our primary objective was to examine external hip joint moments during walking in people with mild radiographic hip osteoarthritis (OA) with and without symptoms and disease-free controls. Three groups were compared (symptomatic with mild radiographic hip OA, n = 12; asymptomatic with mild radiographic hip OA, n = 13; OA-free controls, n = 20). Measures of the external moment (peak and impulse) in the sagittal, frontal and transverse plane during walking were determined. Variables were compared according to group allocation using mixed linear regression models that included individual gait trials, with group allocation as fixed effect and walking speed as a random effect. Participants with evidence of radiographic disease irrespective of symptoms walked 14-16% slower compared to disease-free controls (p = 0.002). Radiographic disease without symptoms was not associated with any altered measures of hip joint moment compared to asymptomatic OA-free controls once speed was taken into account (p ≥ 0.099). People with both mild radiographic disease and symptoms had lower external peak hip adduction moment (p = 0.005) and lower external peak internal rotation moment (p < 0.001) accounting for walking speed. Among angular impulses, only the presence of symptoms was associated with a reduced hip internal rotation impulse (p = 0.002) in the symptomatic group. Collectively, our observations suggest that symptoms have additional mechanical associations from radiographic disease alone, and provide insight into potential early markers of hip OA. Future research is required to understand the implications of modifying walking speed and/or the external hip adduction and internal rotation moment in people with mild hip OA.

Gait asymmetries in unilateral symptomatic hip osteoarthritis and their association with radiographic severity and pain.

INTRODUCTION:: Little is known about the loading patterns in unilateral hip osteoarthritis (OA) and their relationship to radiographic severity and pain. We aimed to examine the loading patterns at the hips of those with unilateral symptomatic hip OA and identify associations between radiographic severity and pain with loading alterations. METHODS:: 61 subjects with symptomatic unilateral hip OA underwent gait analyses and evaluation for radiographic severity (Kellgren-Lawrence [KL]-grade) and pain (visual analogue scale) at bilateral hips. RESULTS:: Hip OA subjects had greater range of motion and higher hip flexion, adduction, internal and external rotation moments at the contralateral, asymptomatic hip compared to the ipsilateral hip ( p < 0.05). Correlations were noted between increasing KL-grade and increasing asymmetry of contralateral to ipsilateral hip loading ( p < 0.05). There were no relationships with pain and loading asymmetry. DISCUSSION:: Unilateral symptomatic hip OA subjects demonstrate asymmetry in loading between the hips, with relatively greater loads at the contralateral hip. These loading asymmetries were directly related to the radiographic severity of symptomatic hip OA and not with pain. CONCLUSION:: Additional research is needed to determine the role of gait asymmetries in disease progression.

The Association of Vibratory Perception and Muscle Strength With the Incidence and Worsening of Knee Instability: The Multicenter Osteoarthritis Study.

OBJECTIVE: To examine neuromuscular factors that predict the incidence and progression of knee instability symptoms in older adults with or at high risk of knee osteoarthritis (OA). METHODS: At the 60-month clinic visit, participants in the Multicenter Osteoarthritis Study underwent evaluation of quantitative vibratory sense at the knee and isokinetic quadriceps muscle strength. At this 60-month visit, participants were also asked about knee buckling and sensations of knee shifting or slipping without buckling in the past 3 months and then were asked the same questions at the 72- and 84-month follow-up visits. We performed a person-based analysis using Poisson regression analysis with robust error variance to estimate adjusted relative risks (RRs) for the association of vibratory sense and muscle strength with the incidence and worsening of knee slipping/shifting, buckling, and overall knee instability symptoms (either buckling or knee shifting/slipping), with adjustment for relevant confounders. RESULTS: A total of 1,803 participants (61% women) were included. Approximately one-third of the participants reported incident or worsening of instability symptoms over the study period. After adjustment for relevant confounders, better vibratory acuity (adjusted RR 0.78, 95% confidence interval [95% CI] 0.56-1.09), P = 0.020 for trend) and greater quadriceps strength (adjusted RR 0.53, 95% CI 0.38-0.75, P < 0.001) protected against incident knee instability symptoms. Greater quadriceps strength (adjusted RR 0.73, 95% CI 0.58-0.92, P = 0.008) also protected against worsening of knee instability symptoms. CONCLUSION: Vibratory acuity and quadriceps muscle strength are important predictors of the incidence and worsening of knee instability over 2 years. These neuromuscular factors are potentially modifiable and should be considered in interventional studies of instability in persons with or at risk of knee OA.

A reduction in the knee adduction moment with medial thrust gait is associated with a medial shift in center of plantar pressure.

The knee adduction moment (KAM) is an established marker of compartmental load distribution across the tibiofemoral joint. Research suggests a link between the magnitude of the KAM and center of plantar pressure (COP) thus alterations in the two may be related. The objective of this study was to investigate whether the COP predictably shifts when the KAM is reduced through a gait adaptation. Twenty healthy adults underwent gait analysis walking with their normal gait pattern and with medial thrust gait, a gait adaptation known to significantly reduce the KAM. Simultaneous COP and 3-D kinetics were acquired to allow for a comparison of the change in COP to the change in the KAM. The COP was quantified by determining a customized medial-lateral pressure index (MLPI) which compares the COP tracing line during the first and second halves of stance to the longitudinal axis of the foot. Linear regressions assessing the association between the changes in KAM and MLPI indicated that 48.3% (p=0.001) of the variation in MLPI during the first half of stance can be explained by the KAM during the same period. A trend was observed between the association between the KAM and MLPI during the second half of stance (R(2)=0.16, p=0.080). Backwards elimination regression analysis was used to explore whether simultaneous consideration of the KAM and other potential confounding factors such as sagittal plane knee moments and speed explained variance in the MLPI during the first half of stance. Only the KAM exhibited explanatory power (ß=0.695, p=0.001). During medial thrust gait, a reduction in the KAM was associated with a medial shift in the MLPI, and an increase in the KAM was associated with a lateral shift in the MLPI, especially in the first half of the stance phase. Together, these results demonstrate an inherent link between foot pressure and the KAM during medial thrust gait, and suggest that manipulating foot pressure may be a biomechanical mechanism for an intervention designed to improve loading conditions at the knee.

Symptoms of Knee Instability as Risk Factors for Recurrent Falls.

OBJECTIVE: Whether knee instability contributes to the increased risk of falls and fractures observed in persons with knee osteoarthritis (OA) has not been studied. We examined the association of knee buckling with the risk of falling and fall-related consequences in older adults with, or at high risk for, knee OA. METHODS: At the 60-month visit of the Multicenter Osteoarthritis Study, men and women ages 55-84 years were asked about knee buckling in the past 3 months and whether they fell when a knee buckled. Falls and fall-related injuries in the past 12 months and balance confidence were assessed at 60 and 84 months. Multivariate logistic regression was used to assess the association of knee buckling with falls and their consequences. RESULTS: A total of 1,842 subjects (59% women, mean ± SD age 66.9 ± 7.8 years, and body mass index 30.3 ± 5.7) were included. At 60 months 16.8% reported buckling and at 84 months 14.1% had recurrent (≥2) falls. Bucklers at 60 months had a 1.6- to 2.5-fold greater odds of recurrent falls, fear of falling, and poor balance confidence at 84 months. Those who fell when a knee buckled at baseline had a 4.5-fold, 2-fold, and 3-fold increased odds 2 years later of recurrent falls, significant fall injuries, and fall injuries that limited activity, respectively, and were 4 times more likely to have poor balance confidence. CONCLUSION: Interventions that reduce knee buckling may help prevent falls, fall-related injuries, and adverse psychological consequences of falls in persons with knee OA.

Aging or osteoarthritis: which is the problem?

OA is not an inevitable consequence of aging, but aging-related changes in the musculoskeletal system increase the risk of developing OA if other risk factors are also present. The joint is a functioning biomechanical unit of the neuromuscular system. Factors that contribute to the development of joint pain and loss of joint function include those associated with aging, those associated with underuse or misuse of the musculoskeletal system, and those associated directly with the development of OA. Complex interactions exist among many of these factors such as strength, balance, and proprioception, which are affected by aging, underuse, and OA. Many older adults who have joint pain and loss of function do not exhibit structural changes of OA that can be detected by standard radiography. When structural damage is present, its contribution to pain and disability is not always clear. In the absence of pharmacologic agents that can prevent the progression of structural damage in OA, management of older adults who have joint pain and loss of function should focus on improving neuromuscular function and preventing further declines.