Individual joint contributions to forward propulsion during treadmill walking in women with hip osteoarthritis.

As we age, reliance on the ankle musculature for push-off during walking reduces and increased reliance on the hip musculature is observed. It is unclear how joint pathology like osteoarthritis may affect this distal-to-proximal redistribution of propulsion. Here, we revisited a proof-of-concept study to study the effect of split-belt treadmill training, designed to reduce step length asymmetry, on forward propulsion during walking. Eleven women with hip osteoarthritis and five age-matched control participants walked on an instrumented split-belt treadmill at their preferred speed (hip osteoarthritis: 0.73 ± 0.11 m/s; controls: 0.59 ± 0.26 m/s). Women with hip osteoarthritis had less ankle power and propulsive force than controls, and greater hip contributions to forward propulsion on their involved limb. Following split-belt treadmill training, propulsive force increased on the involved limb. Five of 11 participants experienced a change in redistribution ratio that was greater than the minimal clinically meaningful difference. These "responders" had greater variability in pre-training redistribution ratio compared to non-responders. Women with hip osteoarthritis had poorer propulsive gait mechanics than controls yet split-belt treadmill training improved propulsive force. Redistribution ratio also changed in participants with high baseline variability. Our results suggest that split-belt treadmill training may be beneficial to people with hip osteoarthritis who have high variability in walking parameters. Further, the age-related shift to increased hip contributions to propulsion across populations of older adults may be due to increased variability during walking.

Diminished vibration perception and greater pressure pain sensitivity are associated with worse knee osteoarthritis outcomes across sex and race.

OBJECTIVE: To examine associations of vibration sensitivity and pressure pain sensitivity with knee osteoarthritis (OA) outcomes across sex and race, which may relate to known sex and race disparities in clinical outcomes. DESIGN: Data were from the 2013-2015 visit of the Johnston County Osteoarthritis Project. Exposures were vibration perception threshold (VPT) measured at the bilateral medial femoral condyle (MFC) and first metatarsophalangeal joint (MTP), and pressure pain threshold (PPT) measured at the bilateral upper trapezius. Outcomes were knee pain severity and presence of knee symptoms, radiographic knee OA, and symptomatic knee OA in each knee. Cross-sectional associations of the exposures with the outcomes were examined using logistic regression models, overall and separately by sex and race. RESULTS: In the VPT and PPT analyses, 851 and 862 participants (mean age 71 years, 68% female, 33% Black, body mass index 31 kg/m2) and 1585 and 1660 knees were included, respectively. Higher VPT (lower vibration sensitivity) at the MFC and first MTP joint was associated with all outcomes. Lower PPT (greater pressure pain sensitivity) was associated with greater knee pain severity. Associations of VPT and PPT with all outcomes were similar among females and males and Black and White individuals. CONCLUSIONS: Diminished vibration perception and greater pressure pain sensitivity were cross-sectionally associated with worse knee OA outcomes. Despite differences in VPT and PPT among females and males and Black and White adults, associations with knee OA outcomes did not differ by sex or race, suggesting neurophysiological differences do not relate to established disparities.

Gait speed and kinesiophobia explain physical activity level in adults with osteoarthritis: A cross-sectional study.

Identifying potential contributing factors for physical inactivity in people with knee osteoarthritis is vital for designing practical activity promoting interventions. Walking is a common activity, but it is unknown how gait characteristics may influence physical activity and if psychological factors, specifically fear of movement (kinesiophobia), contribute to this relationship. The aim of our study was to investigate the contributions of select gait parameters and kinesiophobia to activity levels. Cross-sectional data from 40 participants (F 24|M 16; age 57.6 ± 8.9 years; BMI 34.7 ± 7.0 kg/m2 ) with uni- or bilateral knee osteoarthritis were included. Physical activity and kinesiophobia were assessed by self-report using the University of California, Los Angeles activity rating scale, and Tampa scale for kinesiophobia, respectively. Gait parameters were collected with three-dimensional gait analysis while participants walked on an instrumented split-belt treadmill at a self-selected speed. Higher peak sagittal plane joint moments at the ankle (ρ = 0.418, p = 0.007), and hip (ρ = 0.348, p = 0.028), faster self-selected gait speed (ρ = 0.553, p < 0.001), and less kinesiophobia or fear of movement (ρ = -0.695, p < 0.001) were independently related to higher physical activity level in adults with knee osteoarthritis. In hierarchical regression models, after accounting for covariates, only self-selected gait speed, and kinesiophobia significantly contributed to explaining the variation in physical activity level. Statement of clinical significance: Interventions aimed at improving physical activity participation in those with lower limb osteoarthritis should consider assessing the contribution of pain-related fear of movement.

Artificial intelligence and machine learning as a viable solution for hip implant failure diagnosis-Review of literature and in vitro case study.

The digital health industry is experiencing fast-paced research which can provide digital care programs and technologies to enhance the competence of healthcare delivery. Orthopedic literature also confirms the applicability of artificial intelligence (AI) and machine learning (ML) models to medical diagnosis and clinical decision-making. However, implant monitoring after primary surgery often happens with a wellness visit or when a patient complains about it. Neglecting implant design and other technical errors in this scenario, unmonitored circumstances, and lack of post-surgery monitoring may ultimately lead to the implant system's failure and leave us with the only option of high-risk revision surgery. Preventive maintenance seems to be a good choice to identify the onset of an irreversible prosthesis failure. Considering all these aspects for hip implant monitoring, this paper explores existing studies linking ML models and intelligent systems for hip implant diagnosis. This paper explores the feasibility of an alternative continuous monitoring technique for post-surgery implant monitoring backed by an in vitro ML case study. Tribocorrosion and acoustic emission (AE) data are considered based on their efficacy in determining irreversible alteration of implant material to prevent total failures. This study also facilitates the relevance of developing an artificially intelligent implant monitoring methodology that can function with daily patient activities and how it can influence the digital orthopedic diagnosis. AI-based non-invasive hip implant monitoring system enabling point-of-care testing.

Sagittal plane ankle kinetics are associated with dynamic hip range of motion and gait efficiency in women with hip osteoarthritis.

Loss of sagittal plane hip range of motion (ROM) is a commonly reported walking gait impairment in people with hip osteoarthritis (OA). The purpose of this study was to evaluate whether sagittal plane hip ROM reduction and the resulting altered sagittal plane ankle kinetics during gait influence the energy cost of walking in people with hip OA. We evaluated 24 women with unilateral hip OA (60 ± 9.1 years; 29.4 ± 6.1 kg/m2 ). Sagittal plane hip ROM and peak ankle dorsiflexion moment were assessed by instrumented gait analysis. We also used a portable metabolic system to measure the energy cost of walking. Pearson correlations and regression analyses were performed to test our hypotheses. We found that greater involved limb sagittal plane hip ROM was associated with a larger ankle peak dorsiflexion moment at push-off during gait (R = 0.50, p = 0.01). Greater involved limb peak ankle dorsiflexion moment at push-off was associated with a lower oxygen consumption during gait (R = -0.51, p = 0.01). Involved limb peak ankle dorsiflexion moment at push-off predicted 26% of the variance in O2 cost. Statement of Clinical Significance: Sagittal plane hip ROM was associated with peak ankle dorsiflexion moment at push-off during gait in women with hip OA. Moreover, peak ankle dorsiflexion moment at push-off was associated with the energy cost of walking. Therefore, modifying sagittal plane hip ROM and peak ankle dorsiflexion moment could be a possible rehabilitation strategy to improve gait efficiency in women with hip OA.

Fall experiences from the perspectives of people with osteoarthritis: in their own words.

PURPOSE: To explore real-life experiences of people with osteoarthritis (OA) to increase understanding of how they perceive contributing factors to falls, circumstances at time of falls, and consequences of falls. MATERIALS AND METHODS: Four focus groups of 3-7 people with OA from the Chicago, IL, USA, and neighboring areas were conducted remotely via web-based videoconferencing. Inclusion criteria included history of falls in previous 12 months and hip and/or knee OA. Focus group transcripts were coded and analyzed using a modified grounded theory approach to identify themes. RESULTS: Focus group participants (n = 17) described experiences associated with fall-related events that resulted in the identification of four themes: (1) perception of falls and fall risks can be influenced by OA symptoms, (2) ability to remember circumstances of falls are influenced by consequences, (3) behaviors and attitudes that address OA symptoms and avoidance of falls are similar and (4) OA symptoms and falls have common psychological impacts on lives. CONCLUSION: Our study highlights how people with OA define falls, perceive contributing factors to falls, and describe general and OA-related factors that contributed to their fall experiences. The shared experiences contributed to the creation of themes that represented various aspects of the circumstances and impact of falls. Consideration for the identified themes may enhance recording and reporting of falls, contribute to development of improved fall risk assessment tools, and prioritize research into the biopsychosocial effects of falls in people with OA.IMPLICATIONS FOR REHABILITATIONInformation about circumstances of a fall such as location, activity, and symptoms of osteoarthritis may be beneficial in creating tailored fall prevention training and education.Falls are a common problem for people with lower limb osteoarthritis that can lead to negative changes in activity and quality of life.The psychological impact of osteoarthritis symptoms may be contributing to fear of falling and decrease participation in daily activities.Awareness of the perceptions people with osteoarthritis have about their symptoms may provide educational and training opportunities to address the benefits of different therapeutic treatments.Awareness of perceptions people with osteoarthritis have about their risk of falling may provide educational and training opportunities to address the benefits of different therapeutic treatments.

Total hip replacement monitoring: numerical models for the acoustic emission technique.

Any mechanical instability associated with total hip replacement (THR) excites elastic waves with different frequencies and propagates through the surrounding biological layers. Using the acoustic emission (AE) technique as a THR monitoring tool provides valuable information on structural degradations associated with these implants. However, several factors can compromise the reliability of the signals detected by AE sensors, such as attenuation of the detected signal due to the presence of biological layers in the human body between prosthesis (THR) and AE sensor. The main objective of this study is to develop a numerical model of THR that evaluates the impact of biological layer thicknesses on AE signal propagation. Adipose tissue thickness, which varies the most between patients, was modeled at two different thicknesses 40 mm and 70 mm, while the muscle and skin thicknesses were kept to a constant value. The proposed models were tested at different micromotions of 2 µm, 15-20 µm at modular junctions, and different frequencies of 10-60 kHz. Attenuation of signal is observed to be more with an increase in the selected boundary conditions along with an increase in distance the signals propagate through. Thereby, the numerical observations drawn on each interface helped to simulate the effect of tissue thicknesses and their impact on the attenuation of elastic wave propagation to the AE receiver sensor.

Strength and physical activity in osteoarthritis: The mediating role of kinesiophobia.

The aim of this study was to investigate the association between muscle strength and physical activity level in people with knee osteoarthritis (OA), and determine whether this association is mediated by pain-related fear of movement (kinesiophobia) and self-reported pain. Cross-sectional data from 37 subjects (age 58.8 ± 8.6 years, 25F/12M, BMI 33.5 ± 6.4 kg/m2 ) with OA of the knee were used. Isometric knee extensor and flexor muscle strength were measured using an isokinetic dynamometer. Physical activity, kinesiophobia, and pain were assessed by self-report using the University of California, Los Angeles activity rating scale, Tampa Scale for Kinesiophobia, and The Knee Injury and Osteoarthritis Outcome Score pain subscale, respectively. The associations between strength measures, physical activity, kinesiophobia, and pain scores, were modeled by performing a parallel multiple mediation analysis and the significance of mediational effects (kinesiophobia and pain) were tested using a bootstrap approach. Lower knee flexion and extension strength were associated with lower physical activity scores and these relationships were mediated by higher kinesiophobia scores (more fear) but not pain scores. Knee extension strength was directly associated with physical activity scores after controlling for kinesiophobia and pain scores. These results suggest that muscle strength can influence physical activity directly and indirectly through fear of movement. Assessing these measures together in this population may help clinicians identify patients that are more likely to avoid physical activities due to not only muscle weakness but also fear of movement.

Impact of step length asymmetry on walking energetics in women with hip Osteoarthritis: A pilot study.

A step length difference between the involved and uninvolved limbs in participants with hip osteoarthritis (OA) has been reported. The implications of step length asymmetry on other aspects of walking mechanics are as yet unknown. The objective of the current study was to evaluate the consequences of step length asymmetry on motion of the center of mass (COM) and energy cost of walking. We hypothesized that (i) increased step length asymmetry is associated with decreased mechanical energy exchange; (ii) decreased mechanical energy exchange is associated with increased O2 cost; (iii) increased step length asymmetry is associated with increased oxygen O2 cost during walking in women with hip OA. We evaluated 24 women with unilateral hip OA using motion analysis as participants walked on a treadmill at self-selected speeds. Kinematic data were collected to compute step length asymmetry and mechanical energy exchange through the motion of COM. We also used a portable metabolic system to measure the energy cost of walking simultaneously. We used Pearson correlations and linear regression to test our hypotheses. We found that more asymmetric step lengths were associated with lower mechanical energy exchange (R2 = 0.231, p = 0.017). More mechanical energy exchange was associated with lower O2 cost during gait (R2 = 0.284, p = 0.009). Mechanical energy exchange predicted 54.5% of the variance in O2 cost after adjusting for self-selected walking speed. Findings suggest that modifying step length asymmetry could enhance metabolic gait efficiency indirectly by improving mechanical energy exchange in participants with hip OA.

Walking energetics and fatigue are associated with physical activity in people with knee osteoarthritis.

BACKGROUND: Aberrant biomechanics may influence osteoarthritis-associated physical activity limitations. Our purpose was to evaluate the association of walking energetics, fatigue, and fatigability on physical activity in people with knee osteoarthritis. We hypothesized that using increased energy for walking, experiencing more fatigue, or being more fatigable are associated with less activity, and that fatigue and fatigability mediate the relationships between walking energetics and physical activity. METHODS: We tested our hypothesis in 30 people with knee osteoarthritis (age 58 ± 9 years, 10 Male/20 Female). Physical activity was assessed using the University of California Los Angeles score. We used a six-minute walk test to predict VO2max. Next we used a portable oxygen exchange system to measure relative energy used (100 * VO2rate/VO2max) and VO2cost during walking at preferred speeds. We used the Knee injury and Osteoarthritis Outcome Score subscale to quantify pain, and the Patient Reported Outcome Measurement Instrument System Fatigue survey and a treadmill-based fatigability test to assess fatigue and fatigability. Spearman correlations, regression, and mediation analysis were used to test our hypotheses. FINDINGS: Greater energy used during walking, fatigue, and fatigability were all associated with lower physical activity (rho = -0.585 to -0.379, P = 0.001 to 0.043). These associations persisted when incorporating pain into the models. Fatigue and fatigability mediated the associations between walking energetics and physical activity. INTERPRETATION: Walking energetics could be a useful target to promote physical activity in people with osteoarthritis. Further, the effect of walking energetics on physical activity may work through its impact on fatigability.

Walking energetics and abductor strength are associated with physical activity in older women with hip osteoarthritis.

BACKGROUND: Osteoarthritis (OA) can hinder physical activity in older adults for reasons that are not fully understood. Functional barriers may exist such as reduced muscle strength around the affected joint, potentially affecting physical activity. Aging-associated declines in energy capacity may also be exacerbated by OA. These factors may work together to influence physical activity in people with OA. RESEARCH QUESTION: Our objective was to evaluate the combined role of walking energetics and hip abductor strength on physical activity in older women with hip OA. METHODS: We evaluated 30 women with moderately symptomatic hip OA (61 ± 10 yrs; 30.7 ± 4.9 kg/m2) in this cross-sectional observational study. We measured physical activity using the UCLA activity score and quantified activity frequency and intensity using accelerometers worn for seven days (7 ± 2 days). We used a portable oxygen exchange system to measure energy used during walking at preferred speeds (relative to total energy capacity assessed using a six-minute walk test) and a dynamometer to measure hip abductor strength. We used Pearson correlations and regression analysis to test our hypotheses. RESULTS: Greater energy used during walking was associated with lower self-reported physical activity (R=-0.626, p < 0.001), more sedentary time (R = 0.567, p = 0.002), and less light activity time (R=-0.644, p < 0.001). Lower hip abductor strength was associated with lower self-reported physical activity (R = 0.406, p = 0.039). While there was no association between hip abductor strength and energy used during walking, together these variables predicted 55.5 % of the variance in self-reported physical activity. SIGNIFICANCE: Results suggest intervention targets to promote physical activity in this population.

Aerobic capacity and fatigability are associated with activity levels in women with hip osteoarthritis.

Physical activity is important for physical function and pain relief in people with lower extremity osteoarthritis (OA). Unfortunately, people with OA are not as active as their peers without OA. The objective of this study was to determine whether aerobic capacity and fatigability are associated with physical activity in women with hip OA. We conducted a cross-sectional analysis of 36 women with hip OA. We assessed aerobic fitness as predicted VO2 max from a 6-min walk test. We assessed fatigability using a treadmill test. Finally, we assessed self-reported physical activity using the UCLA activity scale and quantified steps per day and activity intensity using accelerometers. We used Pearson correlations to determine associations. We used regression analysis to determine whether fatigability mediated the association between aerobic fitness and physical activity. On average, subjects were moderately active via the UCLA score (5.2 ± 1.3 out of 10). Aerobic fitness (R = 0.582, p < .001) and fatigability (R = 0.516, p =.003) were significantly correlated with UCLA scores. However, aerobic fitness was the best predictor of UCLA scores, as well as sedentary time, and time spent in light activity. Fatigability was not a mediator between aerobic fitness and UCLA scores. Aerobic fitness and fatigability may be modifiable barriers to physical activity in people with OA. Future interventional studies should examine whether improving aerobic fitness improves physical activity or fatigability.

Task-Specific Perturbation Training Improves the Recovery Stepping Responses by Women With Knee Osteoarthritis Following Laboratory-Induced Trips.

Trip-specific training improves the kinematics of trip-specific compensatory stepping response (CSR) in the laboratory and reduces prospectively measured trip-related fall-rate of middle age and older women. We examined whether one session of trip-specific perturbation training could improve recovery step kinematics in women with knee osteoarthritis (OA), a condition known to increase fall risk. Seventeen women with self-reported symptomatic knee OA (age 61.1 ± 7.7 years, body mass index [BMI] 29.7 ± 5.9 kg/m2 ) and 22 control women (age 59.5 ± 6.8 years, BMI 28.4 ± 6.2 kg/m2 ) completed a brief training protocol consisting of 20 trials of treadmill-delivered trip-specific perturbations. We assessed pre- and post-training recovery step length and trunk kinematics at the instant of recovery step completion. Repeated-measures analysis of variance was used to determine the significance of between-group differences following the training protocol, and to evaluate the significance of within-group pre-to-post changes in the variables of interest. The group by training interaction effects for step length (p = 0.466), trunk flexion angle (p = 0.751), and trunk angular velocity (p = 0.413) were not significant and the pre-to-post changes in step length were not significant (p = 0.286). However, pre-to-post trunk flexion angle improved by 26% and 34% in the OA and control groups, respectively (p < 0.001) and trunk flexion angular velocity decreased by 193% in the OA group and by 32% in the control group, respectively (p < 0.001), often reflecting a transition to the direction of extension. The results suggest that trip-specific training can improve CSR kinematics in women with knee OA. It is important to determine, the effectiveness of trip-specific training in decreasing trip-specific fall-rate by women with knee OA. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:663-669, 2020.

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.

Static and dynamic abductor function are both associated with physical function 1 to 5 years after total hip arthroplasty.

BACKGROUND: A subset of total hip arthroplasty patients experience functional impairments past the first postoperative year. Poor hip abductor function is common before and in the early postoperative period. It is not known if abductor impairment is associated with long-term functional impairment. This study evaluated the relationships between static and dynamic abductor function and performance-based and self-reported function >1 year post-total hip arthroplasty. METHODS: Eighteen adults 1-5 years post-total hip arthroplasty participated. Static and dynamic abductor function were assessed through dynamometry and gait analysis, respectively. Subjects completed four physical performance tests and two self-report instruments. FINDINGS: Higher peak isometric abductor strength was associated with better performance-based function (P ≤ 0.001-0.030) and with self-reported function (P ≤ 0.001-0.012). Higher peak external adduction moment was associated with better results on 3 of 4 performance tests (P = 0.007-0.026). Together, static and dynamic abductor function predicted 35-77% of the variation in physical function. Abductor strength best predicted walking test results and self-reported function, while dynamic abductor function best predicted tests involving sit-to-stand INTERPRETATION: Static and dynamic abductor function were associated with physical function 1-5 years after total hip arthroplasty. These results support further investigation of interventions targeting abductor function for persons experiencing persistent impairments.

Step Length Asymmetry and Its Associations With Mechanical Energy Exchange, Function, and Fatigue After Total Hip Replacement.

Abnormalities in gait remain after total hip replacement (THR). The purpose of this study was to evaluate step length asymmetry and its links to other aspects of gait and physical function after THR and to investigate links with mechanical energy exchange. The rationale is that step length asymmetry may influence gait efficiency, which could adversely influence fatigue and physical function. We evaluated 18 participants (6 males and 12 females) 1-5 years post-THR. Step length symmetry and mechanical energy exchange were assessed by instrumented gait analysis. Fatigue was assessed using a PROMIS Fatigue Short Form. We assessed physical function using a 6-minute walk test (6MWT). We used a one sample T test to determine whether the symmetry index (SI) was significantly different from 0 and Pearson's correlations to explore associations among the variables. The step length SI was statistically significantly different from zero (p=0.01). A more symmetric step length was associated with better 6MWT (R=-0.57, p=0.03). Higher (better) mechanical energy exchange was associated with more fatigue (R=0.50, p=0.04). Mechanical energy exchange was not associated with step length SI or 6MWT. Better 6MWT was associated with less fatigue (R=-0.61, P=0.01). This suggests that the association between step length symmetry and function is not directly governed by its effect on the energy exchange. Additionally, after a relatively long period of postsurgery, participants may have adapted their gait by increasing mechanical energy exchange to minimize fatigue. Statement of Clinical Significance: A gait retraining intervention targeting step length symmetry could improve function without adversely affecting walking energetics in THR patients. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1563-1570, 2019.

Hypoesthesia after anterior cruciate ligament reconstruction: The relationship between proprioception and vibration perception deficits in individuals greater than one year post-surgery.

BACKGROUND: While surgical reconstruction restores mechanical stability following anterior cruciate ligament (ACL) rupture, many experience early-onset osteoarthritis despite surgery. Neurophysiological changes are hypothesized to contribute to knee osteoarthritis progression. Proprioceptive deficits have been reported following ACL injury/reconstruction; however, vibration perception threshold (VPT) has been less studied. This study explored relationships between pain, VPT, proprioception, function, and strength following ACL-reconstruction. METHODS: Twenty individuals (27 ±â€¯6 years; 10 males) (standard deviation) status-post ACL-reconstruction were compared with a control group. Measurements included VPT, proprioception (threshold to detect passive movement), pain, function (Knee Outcome Survey (KOS)) and isometric quadriceps strength. Group differences were assessed using Mann-Whitney U tests, side-to-side differences with Wilcoxon Signed Rank tests, and associations evaluated using Spearman correlations. RESULTS: The ACL-reconstruction group had minor functional deficits (15 ±â€¯11%) and resting pain (1.8 ±â€¯1.7). Impaired VPT and proprioception (hypoesthesia) were demonstrated on surgical compared to contralateral and control limbs (p ≤ 0.008). Proprioception was significantly different between contralateral and control knees, but not VPT. Surgical knee proprioceptive deficits and VPT deficits were positively correlated (ρ = 0.462, p = 0.047) but not in controls (ρ = -0.042, p = 0.862). Strength was negatively correlated to pain (ρ = -0.589; p = 0.006), but not to KOS scores, proprioception or VPT (p ≥ 0.099). CONCLUSION: Proprioceptive deficits following ACL injury have been ascribed to loss of afferent input from the torn ligament. Alternatively, multi-modality as well as contralateral sensory deficits suggest a spinal/supraspinal source of neurophysiological findings which may predispose to early osteoarthritis. LEVEL OF EVIDENCE: III.

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.

Duration of symptoms is associated with conditioned pain modulation and somatosensory measures in knee osteoarthritis.

Impaired descending pain inhibition has been linked to chronic pain and poorer patient outcomes. Vibration perception threshold (VPT) has also been observed and linked to radiographic stage of OA. However, it is not known how duration of symptoms may influence these neurophysiological measures. Our purpose was to evaluate the relationship between duration of symptoms and conditioned pain modulation (CPM), a measure of descending pain inhibition, and VPT, and to determine whether these relationships differed in men and women seeking orthopedic care. We evaluated 18 men and 27 women with moderate to severe knee OA. We assessed CPM using a submaximal-effort tourniquet test: Pressure pain threshold (PPT) at the symptomatic knee was evaluated before and after a noxious stimulus. CPM impairment was indicated by a ratio of pre-to-post stimulus PPT ≥1. VPT was assessed using a biothesiometer at the medial femoral condyle. We used chi-square, t-tests and Pearson correlations to address study questions. 72% of men, but only 44% of women had CPM impairment. Duration of symptoms was associated with CPM impairment in women (R = 0.566, p = 0.003) but not men (R = 0.366, p = 0.135). Duration of symptoms was also associated with VPT in both men (R = 0.580, p = 0.012) and women (R = 0.406, p = 0.039). These results suggest that longer duration of knee OA may predict more severe pain sensitization and that important sex differences exist in descending pain inhibition in people with chronic knee OA that may affect disease and course of treatment in male and female patients. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.