Pain sensitization and degenerative changes are associated with aberrant plantar loading in patients with painful knee osteoarthritis

Associations between static foot posture, dynamic in-shoe plantar foot forces and knee pain in people with medial knee osteoarthritis: A cross-sectional exploratory study

OBJECTIVE

To investigate relationships between static foot posture, dynamic plantar foot forces and knee pain in people with medial knee osteoarthritis (OA).

DESIGN

Data from 164 participants with symptomatic, moderate to severe radiographic medial knee OA were analysed. Knee pain was self-reported using a numerical rating scale (NRS; scores 0-10; higher scores worse) and the Knee Injury and Osteoarthritis Outcome Score pain subscale (KOOS; scores 0-100; lower scores worse). Static foot posture was assessed using clinical tests (foot posture index, foot mobility magnitude, navicular drop). Dynamic plantar foot forces (lateral, medial, whole foot, medial-lateral ratio, arch index) were measured using an in-shoe plantar pressure system while walking. Relationships between foot posture and plantar forces (independent variables) and pain (dependent variables) were evaluated using linear regression models, unadjusted and adjusted for sex, walking speed, Kellgren & Lawrence grade, shoe category, and body mass (for dynamic plantar foot forces).

RESULTS

No measure of static foot posture was associated with any knee pain measure. Higher medial-lateral foot force ratio at midstance, and a higher arch index during overall stance, were weakly associated with higher knee pain on the NRS (regression coefficient = 0.69, 95% confidence interval (CI) 0.09 to 1.28) and KOOS (coefficient=3.03, 95% CI 0.71 to 5.35) pain scales, respectively.

CONCLUSION

Dynamic plantar foot forces, but not static foot posture, were associated with knee pain in people with medial knee OA. However, the amount of pain explained by increases in plantar foot force was small; thus, these associations are unlikely to be clinically meaningful.

Robotic-arm assisted versus manual total knee arthroplasty: Functional gait analysis from a randomised controlled trial

The primary aim of this study was to assess whether measures of functional gait assessment were improved with robotic total knee arthroplasty (rTKA) when compared to manual TKA (mTKA). Gait analysis was performed as part of a randomised controlled trial. Walking and relaxed standing assessments were performed using an instrumented mat system. Spatiotemporal variables included gait cycle parameters, anteroposterior and lateral sway, and plantar pressure ratios. Measurements were recorded at pre-operative baseline and 12 months post-operatively. 100 patients were randomised, 50 to each group. Complete gait cycle data were available for 26 rTKA and 23 mTKA patients. Cadence and walking velocity showed overall improvements following surgery, with no difference between the two groups. In the operated limb, overall step and stride times decreased, while step and stride lengths increased. Subgroup analysis showed reduced propulsion time with rTKA, and decreased foot flat and mid stance times with mTKA. Lateral sway was decreased in the rTKA group. Plantar pressure ratios showed an overall increase in hindfoot loading on the operated limb, with no difference between the two groups. No other significant differences were identified between rTKA and mTKA at 12 months, and limitations may include statistical error. A small sample of the study cohort was followed up; analysis may represent the results of satisfied patients with well-functioning TKA. Further study could incorporate proprioceptive and 3D gait analysis techniques to analyse knee kinetics and kinematics with robotic surgery. Pressure mapping could further subdivide the plantar surfaces to explore any nuances in differential loading.

Interplay between noxious heat sensitivity and temporal summation magnitude in patients with fibromyalgia and long-term opioid use

Introduction

In chronic pain conditions such as fibromyalgia (FM), pain amplification within the central nervous system, or "central sensitization," may contribute to the development and maintenance of chronic pain. Chronic pain treatments include opioid therapy, and opioid therapy may maladaptively increase central sensitization, particularly in patients who take opioids long-term. However, it has remained unknown how central sensitization is impacted in patients who use opioids long-term.

Methods

To investigate how long-term opioid therapy affects central sensitization, we used the validated measure of temporal summation. The temporal summation measurement consists of applying a series of noxious stimuli to a patient's skin and then calculating changes in the patient's pain rating to each stimulus. Using this measurement, we evaluated temporal summation in study participants with fibromyalgia who take opioids long-term (i.e., greater than 90 days duration; n = 24, opioid-FM). We compared opioid-FM responses to 2 control groups: participants with fibromyalgia who do not take opioids (n = 33, non-opioid FM), and healthy controls (n = 31). For the temporal summation measurement, we applied a series of 10 noxious heat stimuli (sensitivity-adjusted temperatures) to the ventral forearm (2s duration of each stimulus, applied once every 3 s). Additionally, we collected responses to standard pain and cognitive-affective questionnaires to assess pain severity and other factors.

Results and discussion

Group differences in sensitivity-adjusted stimulus temperatures were observed, with only the non-opioid FM group requiring significantly lower stimulus temperatures (The opioid-FM group also required lower temperatures, but not significantly different from the control group). However, all 3 groups exhibited similar magnitudes of temporal summation. Across combined FM groups, temporal summation negatively correlated with pain severity (r = -0.31, p = 0.021). Within the opioid-FM group, higher pain sensitivity to heat (i.e., lower sensitivity-adjusted temperatures) showed a trend relationship with higher opioid dosage (r = -0.45, p = 0.036), potentially reflective of opioid-related hyperalgesia. Our findings also indicated that heightened pain severity may skew sensitivity-adjusted temporal summation, thereby limiting its utility for measuring central sensitization. Overall, in participants taking opioids, temporal summation may be influenced by hypersensitivity to heat pain, which appeared to vary with opioid dosage.

Effects of a foot-ankle muscle strengthening program on pain and function in individuals with knee osteoarthritis: a randomized controlled trial

BACKGROUND

Foot-ankle exercises could improve pain and function of individuals with KOA and need to be tested.

OBJECTIVE

To investigate whether an 8-week foot-ankle muscle strengthening program is effective for individuals with KOA to reduce pain and improve function.

METHODS

In this randomized controlled trial, individuals diagnosed with clinical and radiographic KOA were randomized into the intervention (supervised foot-ankle strengthening exercise program three times a week for 8 weeks) or control (usual care and recommendations of the healthcare team) group. Effectiveness was assessed by changes in clinical and functional outcomes between baseline and 8 weeks with pain as the primary outcome. ANCOVA tests using the intervention group as a reference and sex, body mass index, and baseline values as covariates assessed between-group differences.

RESULTS

The intervention group showed lower pain scores (-4.4 units; 95%CI = -7.5, -1.1), better function (-7.1 units; 95%CI = -12.7, -1.4), higher total functional score (-11.9 units; 95%CI = -20.7, -3.1), with confidence intervals indicating a potential for the differences to be clinically meaningful, and better scores for the 30-s chair stand test (2.7 repetitions; 95%CI = 1.1, 4.1), with a confidence interval indicating a moderate clinically meaningful difference, compared to the controls.

CONCLUSION

The 8-week foot-ankle exercise program showed positive, and potentially clinically meaningful, effects on knee pain and physical function among individuals with KOA, when compared to usual care.

TRIAL REGISTRATION

NCT04154059. https://clinicaltrials.gov/ct2/show/NCT04154059.

Effects of Custom-made Insoles on Plantar Biomechanics and Upper Extremity Muscle Performance

OBJECTIVE

To investigate the effectiveness of molding custom-made insoles for female patients with foot pain.

METHODS

The study included 20 patients whose insoles were prescribed according to biomechanical evaluations and molded by repositioning the subtalar joint in its neutral position using a simple set of tools. Plantar biomechanics were measured under the following conditions: static stand, walking at self-comfortable walking speed (CWS) barefoot, walking in patient owned running shoes, and walking in running shoes plus insoles. Each patient's upper arm isometric muscle strength and subjective feelings before and after the insole intervention were assessed.

RESULTS

The molded insoles increased plantar contact area both during static standing and walking at CWS compared to the barefoot condition. The insoles also had more evenly distributed plantar contact area and loading rate, with the changes in the medial arch area being most significant. Moreover, the custom-made insole intervention immediately increased maximum resistance and duration of bilateral upper arms, as well as improved foot comfort, especially at the medial arch area during single leg squat tests.

CONCLUSION

Molding custom-made insoles by repositioning the subtalar joint in its neutral position can be accomplished with a simple set of tools, making this method highly applicable for a majority of less developed regions. Insoles molded using this method are effective in immediately improving plantar biomechanics disorders and enhancing isometric upper muscle performance in female patients with foot pain.

Effects of a foot-ankle strengthening programme on clinical aspects and gait biomechanics in people with knee osteoarthritis: protocol for a randomised controlled trial

INTRODUCTION

Studies have indicated that hip and knee muscle strengthening are effective in reducing pain, improving self-reported function and increasing lower limb strength, without, however, decreasing knee joint overload during gait in patients with knee osteoarthritis (KOA). Recent research has shown that strengthening the foot-ankle muscles improved function in diabetic patients and reduced patellofemoral pain. The aim of this paper is to investigate whether an 8-week therapeutic foot-ankle exercise programme improves pain, functionality, foot strength, foot kinematics and knee joint overload during gait, and decreases medication intake in individuals with KOA.

METHODS AND ANALYSIS

This two-arm, prospectively registered, randomised controlled trial with blinded assessors will involve 88 patients with medial tibiofemoral osteoarthritis. Subjects will be randomly allocated to a control group that will receive no specific foot intervention and will follow treatment recommended by the medical team; or an intervention group that will undergo an 8-week physiotherapist-supervised strengthening programme for extrinsic and intrinsic foot muscles, three times a week. The primary outcome will be the pain domain of the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). The secondary outcomes include WOMAC stiffness and function domains, total WOMAC score, physical function, foot muscle isometric strength, foot kinematics and knee kinetics during gait, and medication intake. Data will be analysed on intention-to-treat principles and a per protocol basis.

ETHICS AND DISSEMINATION

Investigators and sponsors will communicate trial results to participants and healthcare professionals through scientific databases and social media. In addition, findings will be reported in peer-review publications, and at national and international conference presentations. Ethics approval: Ethics Committee of the Universidade Federal de São Carlos, São Carlos, SP, Brazil (N° 3.488.466).

TRIAL REGISTRATION NUMBER

NCT04154059.

The relation of peripheral and central sensitization to muscle co-contraction: the MOST study

OBJECTIVE

To examine the relation of pain sensitization to altered motor activity in knee OA as assessed by hamstrings muscle co-contraction during maximal effort knee extension.

DESIGN

Medial, lateral, and overall hamstring co-contraction was assessed in the Multicenter Osteoarthritis (MOST) Study cohort using electromyography during isokinetic knee extension at 60°/second. Mechanical temporal summation of pain (TS) was assessed at the right wrist and pressure pain thresholds (PPT) were assessed at the patellae; PPTs were categorized into sex-specific tertiles. Muscle co-contraction was categorized into age- and sex-specific tertiles. We evaluated the relation of measures of sensitization to muscle co-contraction using a generalized logistic regression model.

RESULTS

1633 participants were included: mean age and BMI was 67.3 ± 7.7 years and 30.3 ± 5.6 kg/m2, respectively; 58% were female. Presence of TS was associated with higher overall (OR 1.3, 95% confidence interval (CI) (1.0-1.8)), medial (1.4 (1.0-1.9), and lateral (1.3 (1.0, 1.9)) hamstring co-contraction. The lowest PPT tertile (greater sensitivity) was associated with higher overall (1.5 (1.0, 2.3)) and medial (1.5 (1.0, 2.3)) hamstring co-contraction compared with those in the highest PPT tertile.

CONCLUSION

Greater pain sensitization, as assessed by presence of TS at the wrist and low patellar PPT, was associated with greater overall and medial hamstring co-contraction during knee extension. This provides support to the possibility that peripheral and/or central nervous system alterations may not only affect pain sensitivity, but also motor function.

Effect of Tai Chi Training on Plantar Loads during Walking in Individuals with Knee Osteoarthritis

Tai Chi is an available method for the treatment of knee osteoarthritis (KOA). The impacts of Tai Chi on plantar loads of individuals with KOA are not fully understood. 46 participants with knee osteoarthritis were randomly assigned into the Tai Chi group (n = 23) or the control group (n = 23). The Tai Chi group attended a 6-month Tai Chi program, and the control group participated in a wellness education program. Novel Pedar-X system was used to collect the peak pressure (PP) and maximum force (MF) during walking before and 6 months after the intervention. Significant higher peak pressure and maximum force were observed in the 4th and 5th metatarsophalangeal joints in the Tai Chi group. However, there were significant declines in the peak pressure of the whole foot and the 2nd and 3rd metatarsophalangeal joints and maximum force of the heel in the control group. These results suggested that individuals with KOA might change the pattern of plantar loads during walking through Tai Chi, and plantar loads would be useful as a parameter to assess the effect of Tai Chi on knee osteoarthritis. This trial is registered with Clinical Trials: CHiCTR-TRC-13003264.

Tarsal Tunnel Mechanosensitivity Is Increased in Patients with Asthma: A Case-Control Study

Background: Based on changes in lung function and musculoskeletal disorders in patients with asthma, this study aimed to compare the tarsal tunnel and fibular bone pressure pain thresholds (PPTs) of patients with asthma and healthy matched-paired controls. Methods: A case-control study was performed. One hundred participants were recruited: 50 asthma patients and 50 healthy matched-paired controls. Bilaterally, tarsal tunnel and fibula bone PPTs were registered. Results: Statistically significant differences (p < 0.01) were shown bilaterally for tarsal tunnel PPT. With the exception of fibula PPT (p > 0.05), asthma patients presented less tarsal tunnel PPT than healthy participants. Statistically significant differences (p < 0.05) were shown for two linear regression prediction models of the right (R² = 0.279) and left (R² = 0.249) tarsal tunnels PPTs as dependent variables, and based on sex, group, contralateral tarsal tunnel PPT and ipsilateral fibula PPT as independent variables. Conclusions: The study findings showed that a bilateral tarsal tunnel mechanosensitivity increase is exhibited in patients diagnosed with asthma. The presence of asthma may bilaterally predict the PPT of tarsal tunnel. These findings may suggest the presence of central sensitization in asthma patients, which could clinically predispose them to musculoskeletal disorders, such as tarsal tunnel syndrome.

Characteristics of Plantar Loads During Walking in Patients with Knee Osteoarthritis

BACKGROUND Knee osteoarthritis (KOA) is a common disease that can change the load on lower limbs during walking. Plantar loads in patients with KOA may provide a basis for clinical decisions regarding footwear and foot orthoses. This study aimed to compare plantar loads in females with and without KOA during gait. MATERIAL AND METHODS Plantar pressure during walking was recorded in 23 females with KOA and 23 females without KOA. Maximum force (MF), contact area (CA), and peak pressure (PP) were measured at 7 different regions underneath the foot, named heel (M1), midfoot (M2), first metatarsophalangeal joint (MPJ) (M3), second MPJ (M4), third to fifth MPJ (M5), hallux (M6), and lesser toes (M7). RESULTS PPs for M2 and (M3) in females with KOA were higher than those in females without KOA. High PPs were also found in females with KOA for M2, M3, and M4. CONCLUSIONS Increased plantar loading in females with KOA may lead to foot pronation and gait changes during walking. Plantar loading may be offered to patients with KOA when considering footwear and foot orthoses.

Perioperative pain management in fast-track knee arthroplasty

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Do foot & ankle assessments assist the explanation of 1 year knee arthroplasty outcomes?

OBJECTIVE

Whilst a number of risk factors for poor patient reported outcome measures (PROMs) following knee arthroplasty (KA) have been identified, unexplained variability still remains. The role of pre-operative foot and ankle status on such outcomes has not been investigated. The aim of this study was therefore to determine the association of clinical foot and ankle assessments with patient reported outcomes 1 year following KA.

DESIGN

One hundred and fifteen participants from the Clinical Outcomes in Arthroplasty Study (COASt), underwent detailed foot and ankle assessments at baseline, prior to KA (2012-2014) and were followed up for self-reported outcomes 1 year after surgery.

RESULTS

Thirty nine percent of subjects reported foot pain at baseline. Mean pre-operative Oxford Knee Score (OKS; 0 [worst] to 48 [best outcome]) was 21 and post-operative OKS score was 38. In fully adjusted analysis pre-operative foot pain was significantly associated with 1 year outcome (risk ratio [RR] 0.78 95% confidence interval [95% CI] 0.62, 0.98). No significant association was observed between ankle dorsiflexion or foot posture and outcome.

CONCLUSIONS

Patients with pre-operative foot pain are more likely to have poorer clinically important outcomes 1 year following KA than patients without foot pain. Static ankle dorsiflexion and foot posture do not further explain post-operative KA outcomes. Consideration should also be given to address pre-operative foot pain when attempting to achieve a good clinical outcome for KA.

Unilateral anterior crossbite induces aberrant mineral deposition in degenerative temporomandibular cartilage in rats

OBJECTIVE

To investigate whether mechanical stress induces mineral deposits that contribute to matrix degradation at the onset of osteoarthritis (OA) in temporomandibular joint (TMJ) cartilage.

DESIGN

Female Spraguee-Dawley rats were subjected to an unilateral anterior crossbite (UAC) procedure. Histology, electron microscopy, and energy dispersive spectrometer (EDS) were used to examine cartilage matrix structures and composition of mineral deposit in the affected TMJ cartilage. Protein and/or RNA expression of phenotypic markers and mineralization modulators and matrix degradation was analyzed by immunohistochemistry and/or real-time PCR. Synthetic basic calcium phosphate (BCP) and calcium pyrophosphate dehydrate (CPPD) crystals were used to stimulate ATDC5 cells for their impact on cell differentiation and gene expression.

RESULTS

Fragmented and disorganized collagen fibers, expanded fibrous spaces, and enhancement of matrix vesicle production and mineral deposition were observed in matrices surrounding hypertrophic chondrocytes in cartilage as early as 2-weeks post-UAC and exacerbated with time. The mineral deposits in TMJ cartilage at 12- and 20-weeks post-UAC had Ca/P ratios of 1.42 and 1.44, which are similar to the ratios for BCP. The expression of mineralization inhibitors, NPP1, ANK, CD73, and Matrix gla protein (MGP) was decreased from 2 to 8 weeks post-UAC, so were the chondrogenic markers, Col-2, Col-X and aggrecan. In contrast, the expression of tissue-nonspecific alkaline phosphatase (TNAP) and MMP13 was increased 4-weeks post-UAC. Treating ADTC5 cells with BCP crystals increased MMPs and ADAMTS5 expression, but reduced matrix production in a time-dependent manner.

CONCLUSION

UAC induces deposition of BCP-like minerals in osteoarthritic cartilage, which can stimulate matrix degradation by promoting the expression of cartilage-degrading enzymes to facilitate OA progression.