EFFECTS OF ORTHOPAEDIC INSOLES ON PATIENTS WITH KNEE OSTEOARTHRITIS: A META-ANALYSIS AND SYSTEMATIC REVIEW

ObjectiveRecent clinical evidence supports that orthopaedic insoles, especially lateral-wedge insoles, can significantly benefit patients with knee osteoarthritis. The aim of this study is to explore the effects of orthopaedic insoles in patients with knee osteoarthritis.MethodsRandomized controlled trials evaluating the effects of orthopaedic insoles on patients with knee osteoarthritis, published up to 16 February 2021, were reviewed and outcomes quantitatively summarized.ResultsA total of 15 studies from 13 randomized controlled trials that involved 1,086 participants were included in this study. All the included studies exhibited a moderate bias risk and were of acceptable quality. The pooled mean difference of pain determined by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was –1.21 (p < 0.001, 95% confidence interval (95% CI) –2.61–0.18) with a high heterogeneity (I² = 75%). In the sensitivity analysis, the overall incidence was –0.20 (p= 0.62, 95% CI= –0.87–0.46) with an accepted heterogeneity (I² = 0%). No difference was observed between the Asian and Caucasian groups (p= 0.28). No significant difference was found in the pain score, Lequesne index or functional improvements.ConclusionMeta-analysis revealed that orthopaedic insoles do not provide relief of pain or improve functionality in patients with knee osteoarthritis.LAY ABSTRACTOsteoarthritis of the knee joint is a progressive degenerative disease, which is fairly common in older adults, and leads to major pain and disability. The development and progression of knee osteoarthritis is exacerbated by excessive load on the medial knee joint. Various forms of orthopaedic insoles, such as insoles that provide arch support, shock-absorbing insoles, and lateral-wedge insoles, are widely used by patients with knee osteoarthritis, and are claimed to provide comfort and better support during walking. However, this meta-analysis and systematic review of randomized controlled trials evaluating the effects of orthopaedic insoles on knee osteoarthritis patients found that orthopaedic insoles do not provide relief of pain or improve functionality in patients with knee osteoarthritis.Key words: osteoarthritis, knee, knee joint, systematic review, meta-analysis

Osteoarthritis (OA) of the knee joint is a chronic degenerative disease, which is progressive and disabling, and is fairly common in older adults. OA of the knee produces major pain and disability is a continuous burden for patients (1, 2). As no cure exists, the aims of clinical management are to minimize pain, improve knee functioning and, crucially, enhance the quality of life of patients. Therefore, conservative non-surgical strategies are normally the first choice for clinical management of knee OA (3).The development and progression of OA of the knee is exacerbated by an excessive load on the medial knee joint (4). Therefore, reducing this load is a vital management strategy for patients with knee OA. During the stance phase of walking, the knee varus moment has been measured to assess the effects of therapy (5). Non-surgical interventions, including valgus bracing, can effectively improve clinical results and reduce the knee adduction moment (6, 7). These treatments, however, are cumbersome and expensive, and may not be appropriate for long-term therapy. In recent years, footwear modifications have been considered as an extensive palliative treatment for patients with knee OA. Orthopaedic insoles are designed to limit medial knee compartment load and effectively to reduce knee varus moment in patients with OA. Various other forms of orthopaedic insoles, such as insoles that provide arch support, shock-absorbing insoles and lateral-wedge insoles, are widely used by patients with knee OA, and are claimed to provide comfort and better support during walking. In recent years, clinical evidence has shown that orthopaedic insoles, especially lateral-wedge insoles, can significantly benefit patients with knee OA (8, 9).A previous meta-analysis (10) reported that knee pain was not attenuated by lateral-wedge insoles and did not facilitate improvements in knee functioning in patients with OA compared with healthy control subjects. However, limited by few included studies, the previous study could not perform more stratified analyses and draw strong conclusions. Several recent randomized controlled trials (RCTs) (11, 12) have focused on this topic and provided new evidence. The current meta-analysis and systematic review investigated the potential benefits of orthopaedic insoles in subjects with knee OA.     

Effects of footwear on medial compartment knee osteoarthritis

This pilot study investigated whether lateral-wedge insoles inserted into shock-absorbing walking shoes altered joint pain, stiffness, and physical function in patients with symptomatic medial compartment knee osteoarthritis (OA). Twenty-eight subjects wore full-length lateral-wedge insoles with an incline of 4 degrees in their walking shoes for 4 weeks. Pain, stiffness, and functional status were measured with the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index at baseline and 4 weeks postintervention. Significant improvements were observed in all three WOMAC subscales (pain, stiffness, and function). Pain scores were significantly reduced for the most challenging activity-stair climbing. Subjects wore insoles daily and tolerated them well. The results of this study indicated that lateral-wedge insoles inserted into shock-absorbing walking shoes are an effective treatment for medial compartment knee OA.     

Immediate Efficacy of Laterally Wedged Insoles With Arch Support on Walking in Persons With Bilateral Medial Knee Osteoarthritis

ObjectiveTo investigate the immediate efficacy of laterally wedged insoles with arch support (LWAS) on gait in persons with bilateral medial knee osteoarthritis (OA).DesignA prospective case-control intervention study.SettingA gait laboratory with a 6-camera motion analysis system and 2 forceplates.ParticipantsFifteen women with bilateral medial knee OA and 15 healthy control subjects (N=30).InterventionsLWAS.Main Outcome MeasuresSubjective knee pain and objective biomechanical indices, namely, joint angles and moments in the frontal plane, frontal plane ground reaction force and lever arm, as well as medial/lateral center of mass and center of pressure during gait.ResultsWhen wearing the LWAS, knee pain during gait in persons with medial knee OA decreased (P=.01). Peak internal knee abductor moments were also reduced (P<.001) with increasing foot progression angles, laterally shifted center of pressure, and a shortened frontal plane lever arm (all P<.05). However, ankle invertor moments were increased (P<.05) when wearing the LWAS.ConclusionsAlthough peak internal knee abductor moment and knee pain were immediately reduced during gait when wearing the LWAS, increased ankle invertor moments were found, suggesting that the LWAS should be used with caution. Strengthening and monitoring the condition of the ankle invertor muscles may be necessary if the LWAS is used as an intervention for persons with bilateral medial knee OA.     

The influence of sex and obesity on gait biomechanics in people with severe knee osteoarthritis scheduled for arthroplasty

BackgroundSex and body mass may influence knee biomechanics associated with poor total knee arthroplasty (TKA) outcomes for knee osteoarthritis (OA). This study aimed to determine if gait differed between men and women, and overweight and class I obese patients with severe knee OA awaiting TKA.Methods34 patients with severe knee OA (average age 70.0 (SD 7.2) years, body mass index 30.3 (4.1 kg/m²)) were recruited from a TKA waiting list. Three-dimensional gait analysis was performed at self-selected walking speed. Comparisons were made between men and women, and overweight (body mass index (BMI) 25.0–29.9 kg/m²) and class I obese (BMI 30.0–34.9 kg/m²) participants. Biomechanical outcomes included absolute and body size-adjusted peak knee adduction moment (KAM), KAM impulse, peak knee flexion moment, as well as peak knee flexion and varus-valgus angles, peak varus-valgus thrust, and peak vertical ground reaction force (GRF).FindingsMen had a higher absolute peak KAM, KAM impulse and peak GRF compared to women, and this sex-difference in frontal plane moments remained after adjusting for body size. However, when additionally adjusting for static knee alignment, differences disappeared. Knee biomechanics were similar between obesity groups after adjusting for the greater body weight of those with class I obesity.InterpretationMen had greater KAM and KAM impulse even after adjustment for body size; however adjustment for their more varus knees removed this difference. Obesity group did not influence knee joint kinematics or moments. This suggests sex- and obesity-differences in these variables may not be associated with TKA outcomes.     

The use of a lateral wedge insole to reduce knee loading when ascending and descending stairs in medial knee osteoarthritis patients

Background

Stair climbing is a challenging task to the elderly being the task with the first complaint in patients with mild to moderate knee osteoarthritis. Stair climbing results in around six times more compressive load transmitted through the knee joint than walking on level ground. The purpose of this study was to assess whether lateral wedge insoles would reduce medial compartment knee loading when ascending and descending stairs in patients with medial knee osteoarthritis.

Methods

Eight patients with medial knee osteoarthritis were tested in random order with and without a pair of 5° off-the-shelf lateral wedge insoles for two separate activities (stair ascent and stair descent). Kinematic and kinetic data were collected for the lower extremity using a sixteen camera motion capture system and two force plates. Primary outcome measures were the external knee adduction moment and the knee adduction angular impulse.

Findings

During stair ascent and descent, lateral wedge insoles significantly (P < 0.05) reduced the 1st peak external knee adduction moment in early stance (ascent 6.8%, descent 8.4%), the trough in mid stance (ascent 13%, descent 10.7%), 2nd peak in the late stance (ascent 15%, descent 8.3%) and the knee adduction angular impulse compared to the control (standard shoe) with large effect sizes (0.75–0.95).

Interpretation

In this first study on stairs, lateral wedge insoles consistently reduced the overall magnitude of medial compartment loading during stair ascent and descent. Further research is needed to determine the relationship of this with clinical results when ascending and descending stairs with lateral wedge insoles.     

Effects of disease severity on response to lateral wedged shoe insole for medial compartment knee osteoarthritis

OBJECTIVE: To determine the effects of lateral wedged insoles on knee kinetics and kinematics during walking, according to radiographic severity of medial compartment knee osteoarthritis (OA). DESIGN: A prospective case control study of patients with medial compartment OA of the knee. SETTING: Gait analysis laboratory in a university hospital. PARTICIPANTS: Forty-six medial compartment knees with OA of 23 patients with bilateral disease and 38 knees of 19 age-matched healthy subjects as controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We measured the peak external adduction moment at the knee during the stance phase of gait and the first acceleration peak after heel strike at the lateral side of the femoral condyles. Kellgren and Lawrence grading system was used for radiographic assessment of OA severity. RESULTS: The mean value of peak external adduction moment of the knee was higher in OA knees than the control. Application of lateral wedged insoles significantly reduced the peak external adduction moment in Kellgren-Lawrence grades I and II knee OA patients. The first acceleration peak value after heel strike in these patients was relatively high compared with the control. Application of lateral wedged insoles significantly reduced the first acceleration peak in Kellgren-Lawrence grades I and II knee OA patients. CONCLUSIONS: The kinetic and kinematic effects of wearing of lateral wedged insoles were significant in Kellgren-Lawrence grades I and II knee OA. The results support the recommendation of use of lateral wedged insoles for patients with early and mild knee OA.     

Association of Hypertension with Knee Pain Severity Among People with Knee Osteoarthritis

PurposeTo examine the association of hypertension with knee pain severity in individuals with knee osteoarthritis (OA).DesignCross-sectional study of baseline data collected by the Osteoarthritis Initiative.MethodsParticipants with knee OA (N=1,363) were categorized into four groups based on blood pressure (BP): 1) systolic < 120 mm HG and diastolic < 80 mm Hg; 2) 120 ≤ systolic < 130 mm Hg and diastolic < 80 mm Hg; 3) 130 ≤ systolic < 140 mm Hg or 80 ≤ diastolic < 90 mm Hg; 4) systolic ≥ 140 mm Hg or diastolic ≥ 90 mm Hg. OA knee pain severity was measured by Pain subscale of Western Ontario and McMaster Universities Osteoarthritis Index in the past 48 hours, Pain subscale of Knee Injury and Osteoarthritis Outcome Score (KOOS) in the past 7 days, and numeric rating scale (NRS) in the past 30 days. Linear regression was used to examine the relationship between hypertension and knee pain severity.ResultsCompared with the normal BP group, individuals with stage 2 hypertension reported significantly higher OA knee pain severity by KOOS in the past 7 days (β=-2.05 [95% CI -4.09, -0.01], p=0.049) and by NRS in the past 30 days (β=0.31 [95% CI 0.01, 0.62], p=0.045) after adjustments for demographic and medical factors.ConclusionsHypertension was associated with higher OA knee pain severity in individuals with knee OA.Clinical ImplicationsNurses can recommend adjunctive non-pharmacological treatments and adherence strategies to help control hypertension, which may help decrease OA knee pain.     

Effectiveness of a lateral-wedge insole on knee varus torque in patients with knee osteoarthritis

OBJECTIVES: To test whether a lateral-wedged insole, inclined at 5 degrees or 10 degrees, significantly reduces knee varus torque during walking in patients with knee osteoarthritis compared with both using no insole and with wearing nonwedged control insoles of the same material and average thickness. DESIGN: Patients with medial knee osteoarthritis were studied while they walked wearing their comfortable shoes (1) without an insole; (2) with a 5 degrees lateral wedge compared with a nonwedged, 3.175-mm (1/8-in) even-thickness control insole; and (3) with a 10 degrees lateral wedge compared with a nonwedged 6.35-mm ((1/4)-in) even-thickness control insole. SETTING: A gait laboratory with 3-dimensional motion analysis and force platform equipment. PARTICIPANTS: Fifteen patients with clinical and radiographic osteoarthritis of the medial compartment of 1 knee. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak external knee varus torques during the stance period of gait. Data regarding lower-extremity joint torques and motions were collected, and knee joint torques using the different insoles and wedges were compared by analysis of variance. RESULTS: Although responses varied among individuals, as a group, both the 5 degrees and 10 degrees lateral-wedge insoles significantly reduced the knee varus torque during walking compared with walking with no insole and walking with nonwedged 3.175-mm and 6.35-mm control insoles. Compared with no insole, the 5 degrees wedge reduced the peak knee varus torque values by about 6% and the 10 degrees wedge reduced the peaks by about 8%. Although there were no significant differences in speed of walking between the conditions, the 10 degrees wedge and 6.35-mm control insoles were associated with varying degrees of discomfort. CONCLUSION: Both wedge insoles are effective in reducing the varus torque during walking beyond what theoretically could be explained by a reduced walking speed or cushioning effect from the insole. These data imply that wedged insoles are biomechanically effective and should reduce loading of the medial compartment in persons with medial knee osteoarthritis. Although the effect of the 5 degrees wedge was smaller, it may be more comfortable than the 10 degrees wedge to wear inside one's own shoes.     

Gait differs between unilateral and bilateral knee osteoarthritis

Creaby MW, Bennell KL, Hunt MA. Gait differs between unilateral and bilateral knee osteoarthritis.ObjectivesTo compare walking biomechanics in the most painful leg, and symmetry in biomechanics between legs, in individuals with (1) unilateral pain and structural osteoarthritis (OA), (2) unilateral pain, but bilateral structural OA, and (3) bilateral pain and structural OA and in (4) an asymptomatic control group.DesignCohort study.SettingLaboratory based.ParticipantsParticipants with symptomatic and/or radiographic medial tibiofemoral OA in one or both knees (n=91), and asymptomatic control participants (n=31).InterventionsNot applicable.Main Outcome MeasureThe peak knee adduction moment, peak knee flexion moment, knee varus-valgus angle, peak knee flexion angle, toe-out, and trunk lean were computed from 3-dimensional analysis of walking at a self-selected speed.ResultsAfter controlling for walking speed, greater trunk lean toward the more painful knee and reduced flexion in the more painful knee were observed in all OA groups compared with the control group. Between-knee asymmetries indicating greater varus angle and a lower external flexion moment in the painful knee were present in those with unilateral pain and either unilateral or bilateral structural OA. Knee biomechanics were symmetrical in those with bilateral pain and structural OA and in the pain free control group.ConclusionsThe presence of pain unilaterally appears to be associated with asymmetries in knee biomechanics. Contrary to this, bilateral pain is associated with symmetry. This suggests that the symptomatic status of both knees should be considered when contemplating unilateral or bilateral biomechanical interventions for medial knee OA.     

Hindfoot Flexibility Influences the Biomechanical Effects of Laterally Wedged Insoles and Ankle-Foot Orthoses in Medial Knee Osteoarthritis

ObjectiveTo investigate the relationship of frontal plane ankle mobility with the effects of an ankle-foot orthosis (AFO) and a laterally wedged insole (LWI) on knee adduction moment (KAM) in the treatment of medial knee osteoarthritis.DesignRandomized, nonblinded crossover trial.SettingOutpatient clinic of university hospital.ParticipantsReferred sample of 20 patients (N=20) with medial knee osteoarthritis stage 1-3 (Kellgren and Lawrence), aged 56.4±6.5 years; 58 patients were assessed, 21 were included, and 1 was a dropout. There were 14 healthy reference participants without knee osteoarthritis (convenience sample) who were matched by age.InterventionsPatients received AFO and LWI for 6 weeks each with gait analysis after each 6-week intervention. Patients underwent additional barefoot gait analysis, walking on even ground and on a cross slope of 5° lateral elevation and standing on inclinations of 0°, 5°, 10°, and 20°.Main Outcome MeasuresSpearman correlation between the immediate change in first peak of KAM with each aid and the change in hindfoot varus on the cross slope relative to level ground.ResultsThe KAM reduction with AFO correlated significantly with hindfoot varus reaction to the cross slope during walking: the greater the hindfoot valgization on the cross slope, the greater the KAM reduction with AFO (Spearman ρ=0.53, P=.02).The KAM reduction with LWI correlated moderately negatively with the change in hindfoot varus: the greater the hindfoot valgization on the cross slope, the smaller the KAM reduction with LWI (r=?0.31 P=.18).ConclusionsLWI may be suitable for patients with limited to normal frontal plane ankle mobility. Patients with greater frontal plane ankle mobility benefit most from frontal plane ankle bridging with AFO. Studies with larger samples are necessary.     

Thermal and mechanical pain sensitization in patients with osteoarthritis of the knee

Objective: The aim was to assess sensitization using quantitative sensory testing in mechanical and thermal modes in individuals with and without osteoarthritis (OA) of the knee. Pain thresholds were correlated with functionality, symptoms of depression and intensity of pain. Methods: Thirty control volunteers and 30 patients with OA of the knee were assessed. Punctate pain thresholds using Von Frey filaments and thermal pain thresholds using a Thermal Sensory Analyzer were evaluated in the periarticular region of the knee and forearm. Using a digital pressure algometer, pressure pain thresholds were assessed in the periarticular region of the knee and on the root exit zone on the lumbar and sacral spine. Results: Punctate, pressure, and thermal pain thresholds differed significantly between participants with and without OA (p < 0.05). Values in those with OA were consistent with pain sensitization. Pressure pain thresholds also showed moderate and negative correlations with data on functionality, symptoms of depression and intensity of pain (?0.36 < r > ?0.56), contributing up to 30% of their variability. Conclusions: Allodynia and hyperalgesia were demonstrated in the OA group, suggesting central sensitization in patients with mild to moderate severity of joint damage. Correlation between mechanical hypersensitivity and psychosocial factors seems to be small, despite of its significance.     

Heightened Flexor Withdrawal Response in Individuals With Knee Osteoarthritis Is Modulated by Joint Compression and Joint Mobilization

Patients with chronic pain often present with hyperalgesia, possibly due to hyperexcitability of nociceptive pathways. The aim of the present study was to investigate alterations in flexor withdrawal reflex (FWR) excitability in individuals with knee osteoarthritis (OA) and the potential effect of specific physical inputs or therapeutic interventions (ie, joint compression and mobilization) on these behaviors. Ten subjects with and 10 without knee OA (age 45–75) were recruited. The FWR was examined utilizing suprathreshold, noxious electrocutaneous stimuli applied at the medial foot. Surface electromyographic (EMG) was recorded from the tibialis anterior (TA) and biceps femoris (BF), and peak joint torques recorded at the hip, knee, and ankle. FWR threshold was ascertained and responses at 2× threshold recorded after the following conditions: a maximal, volitional, joint-compression task, a sham hands-on intervention, and a Grade III oscillatory joint-mobilization intervention. A decreased threshold-to-flexor withdrawal response was found in the OA vs control group (P < .01). EMG and joint-torque FWR responses were further augmented in the OA group following the maximal joint-compression task (P < .05), yet remained unchanged or diminished in controls. Joint mobilization, but not sham intervention, reduced reflex responses significantly, although primarily by decreasing BF activity and knee torques (P < .05).PerspectiveApplication of specific physical inputs to individuals with knee OA similar to those encountered during activity of daily living or during therapeutic interventions appear to modulate involuntary, nociceptive reflex responses. Routine weight-bearing activities such as walking may potentially enhance heightened FWR responses, while joint mobilization, a commonly used clinical intervention, may diminish reflex excitability.     

Efficacy and potential determinants of exercise therapy in knee and hip osteoarthritis: A systematic review and meta-analysis

BackgroundExercise is an effective treatment for osteoarthritis. However, the effect may vary from one patient (or study) to another.ObjectiveTo evaluate the efficacy of exercise and its potential determinants for pain, function, performance, and quality of life (QoL) in knee and hip osteoarthritis (OA).MethodsWe searched 9 electronic databases (AMED, CENTRAL, CINAHL, EMBASE, MEDLINE Ovid, PEDro, PubMed, SPORTDiscus and Google Scholar) for reports of randomised controlled trials (RCTs) comparing exercise-only interventions with usual care. The search was performed from inception up to December 2017 with no language restriction. The effect size (ES), with its 95% confidence interval (CI), was calculated on the basis of between-group standardised mean differences. The primary endpoint was at or nearest to 8 weeks. Other outcome time points were grouped into intervals, from < 1 month to ≥ 18 months, for time-dependent effects analysis. Potential determinants were explored by subgroup analyses. Level of significance was set at P ≤ 0.10.ResultsData from 77 RCTs (6472 participants) confirmed statistically significant exercise benefits for pain (ES 0.56, 95% CI 0.44–0.68), function (0.50, 0.38–0.63), performance (0.46, 0.35–0.57), and QoL (0.21, 0.11–0.31) at or nearest to 8 weeks. Across all outcomes, the effects appeared to peak around 2 months and then gradually decreased and became no better than usual care after 9 months. Better pain relief was reported by trials investigating participants who were younger (mean age < 60 years), had knee OA, and were not awaiting joint replacement surgery.ConclusionsExercise significantly reduces pain and improves function, performance and QoL in people with knee and hip OA as compared with usual care at 8 weeks. The effects are maximal around 2 months and thereafter slowly diminish, being no better than usual care at 9 to 18 months. Participants with younger age, knee OA and not awaiting joint replacement may benefit more from exercise therapy. These potential determinants, identified by study-level analyses, may have implied ecological bias and need to be confirmed with individual patient data.     

Immediate effects of a new microprocessor-controlled prosthetic knee joint: a comparative biomechanical evaluation

Bellmann M, Schmalz T, Ludwigs E, Blumentritt S. Immediate effects of a new microprocessor-controlled prosthetic knee joint: a comparative biomechanical evaluation.ObjectiveTo investigate the immediate biomechanical effects after transition to a new microprocessor-controlled prosthetic knee joint.DesignIntervention cross-over study with repeated measures. Only prosthetic knee joints were changed.SettingMotion analysis laboratory.ParticipantsMen (N=11; mean age ± SD, 36.7±10.2y; Medicare functional classification level, 3–4) with unilateral transfemoral amputation.InterventionsTwo microprocessor-controlled prosthetic knee joints: C-Leg and a new prosthetic knee joint, Genium.Main Outcome MeasuresStatic prosthetic alignment, time-distance parameters, kinematic and kinetic parameters, and center of pressure.ResultsAfter a half-day training and an additional half-day accommodation, improved biomechanical outcomes were demonstrated by the Genium: lower ground reaction forces at weight acceptance during level walking at various velocities, increased swing phase flexion angles during walking on a ramp, and level walking with small steps. Maximum knee flexion angle during swing phase at various velocities was nearly equal for Genium. Step-over-step stair ascent with the Genium knee was more physiologic as demonstrated by a more equal load distribution between the prosthetic and contralateral sides and a more natural gait pattern. When descending stairs and ramps, knee flexion moments with the Genium tended to increase. During quiet stance on a decline, subjects using Genium accepted higher loading of the prosthetic side knee joint, thus reducing same side hip joint loading as well as postural sway.ConclusionsIn comparision to the C-Leg, the Genium demonstrated immediate biomechanical advantages during various daily ambulatory activities, which may lead to an increase in range and diversity of activity of people with above-knee amputations. Results showed that use of the Genium facilitated more natural gait biomechanics and load distribution throughout the affected and sound musculoskeletal structure. This was observed during quiet stance on a decline, walking on level ground, and walking up and down ramps and stairs.     

Biomechanical differences between military patients with patellar tendinopathy and asymptomatic controls during single-leg squatting and gait – A statistical parametric mapping study

BackgroundPrior identification of biomechanical differences between patients with patellar tendinopathy and healthy controls has utilised time-discrete analysis which is susceptible to type I error when multiple comparisons are uncorrected. We employ statistical parametric mapping to minimise the risk of such error, enabling more appropriate clinical decision-making.MethodsLower-limb biomechanics of 21 patients with patellar tendinopathy and 22 controls were captured during walking and three types of squats. A statistical parametric mapping two-sample t-test was used to identify kinematic and kinetic differences between groups for each joint. Paired t-tests were used to compare pain before and after tasks, in patients with patellar tendinopathy.FindingsDuring walking, cases demonstrated reduced knee joint power during initial contact and hip joint power during terminal stance. In squatting, cases demonstrated increased knee abduction angles at various time points of the small knee bend and single-leg squat. Cases demonstrated reduced knee internal rotation moment during the deepest portion of the single-leg squat and single-leg decline squat.InterpretationGait appears unaffected by patellar tendinopathy, likely due to low task difficulty. Elevated knee abductions angles during squatting were confirmed as a key difference in patients with patellar tendinopathy. Reduced knee internal rotation moments in patients were attributed to a potential reduction in hip external rotator strength and possible pain avoidance strategy; however further evidence is required to substantiate these claims. Findings provide a clear rationale for rehabilitation programs to focus on knee stabilisation and strengthening of the muscles surrounding the hip.     

Assessment of Movement-Evoked Pain in Osteoarthritis by the Knee-Bend and CatWalk Tests: A Clinically Relevant Study

Although there are several reports on pain behavioral tests in rat models of knee osteoarthritis (OA), most of them focus on the paw. The aim of this study was to investigate pain-related behaviors on the affected knee joint, the primary source of nociception, in animals with mono-iodoacetate–induced OA, using the knee-bend (which provides information on movement pain) and pin-prick tests, and to evaluate nociception elicited by walking using the CatWalk test. The von Frey and Randall-Selitto tests applied to the paw allowed us to compare our study results with previous studies. A further aim was to compare the behavioral nociceptive responses of the most used doses of mono-iodoacetate, 2 and 3 mg. Knee-bend score of OA animals was higher than those of control animals throughout the study (P < .05). At every time point, the ipsilateral hind-paw load of OA rats, as measured by the CatWalk test, was lower than that of control rats (P < .05), and paw withdraw threshold to von Frey filaments was also decreased (P < .01). No changes were observed in pin-prick and Randall-Selitto tests. Results obtained with the 2 doses of mono-iodoacetate were similar. The knee-bend and CatWalk tests are effective for evaluating movement-related nociception, a hallmark of clinical OA, which was present throughout the experimental period.PerspectiveBehavioral characterization of models of OA pain is important and useful for use in future studies to test pharmacological treatments. Furthermore, it is important to find methods that correlate better with the human symptoms of OA.     

Heightened Flexor Withdrawal Responses in Subjects With Knee Osteoarthritis

Patients with osteoarthritic (OA) knee pain often present with impaired muscle activation and function that may be attributed in part to hyperexcitability of flexion withdrawal reflexes (FWRs). The aim of this study was to investigate alterations in the excitability of FWR in individuals with knee OA and its potential associations with impaired quadriceps activation (QA) and subjective reports of pain. Twenty subjects with and 20 without knee OA (age, 45 to 75 years) participated. Impaired QA was determined in OA subjects during maximal volitional contraction of the quadriceps. FWRs were tested in isometric conditions using electrocutaneous stimulation applied at the medial foot at 1× and 2× FWR threshold and surface electromyographic recordings obtained from tibialis anterior (TA) and biceps femoris (BF). Joint torques at the hip, knee, and ankle were calculated and normalized to body mass. FWR threshold was significantly diminished in OA versus the control group (P < .01). In addition, FWR latencies were consistent with spinally mediated responses, with significantly earlier responses in OA versus control subjects of TA at threshold (P = .002) and BF at suprathreshold stimulation (P = .0006). Impaired QA was found in 4 of 20 OA subjects but was not correlated to FWR threshold or pain levels. Peak joint torques were diminished in the OA versus the control group (P < .0006).PerspectiveIncreased excitability of FWRs was evident in subjects with chronic knee osteoarthritis, including those subjects without resting pain, but was not associated with impaired QA. Management strategies for this patient population must consider altered pain processing in addition to addressing impairments found at the knee.     

The effects of an articulated ankle-foot orthosis with resistance-adjustable joints on lower limb joint kinematics and kinetics during gait in individuals post-stroke

BackgroundResistance is a key mechanical property of an ankle-foot orthosis that affects gait in individuals post-stroke. Triple Action® joints allow independent adjustment of plantarflexion resistance and dorsiflexion resistance of an ankle-foot orthosis. Therefore, the aim of this study was to investigate the effects of incremental changes in dorsiflexion and plantarflexion resistance of an articulated ankle-foot orthosis with the Triple Action joints on lower limb joint kinematics and kinetics in individuals post-stroke during gait.MethodsGait analysis was performed on 10 individuals who were post-stroke under eight resistance settings (four plantarflexion and four dorsiflexion resistances) using the articulated ankle-foot orthosis. Kinematic and kinetic data of the lower limb joints were recorded while walking using a three-dimensional Vicon motion capture system and a Bertec split-belt instrumented treadmill.FindingsRepeated measures analysis of variance revealed that adjustment of plantarflexion resistance had significant main effects on the ankle (P < 0.001) and knee (P < 0.05) angles at initial contact, while dorsiflexion resistance had significant (P < 0.01) main effects on the peak dorsiflexion angle in stance. Plantarflexion and dorsiflexion resistance adjustments appeared to affect the peak knee flexor moment in stance, but no significant main effects were revealed (P = 0.10). Adjustment of plantarflexion resistance also demonstrated significant (P < 0.05) main effects in the peak ankle positive power in stance.InterpretationThis study demonstrated that the adjustments of resistance in the ankle-foot orthosis with the Triple Action joints influenced ankle and knee kinematics in individuals post-stroke. Further work is necessary to investigate the long-term effects of the articulated ankle-foot orthoses on their gait.     

Comparison of peak knee adduction moment and knee adduction moment impulse in distinguishing between severities of knee osteoarthritis

Background

The peak knee adduction moment is a valid proxy for medial knee joint loading. However as it only measures load at one instance of stance, knee adduction moment impulse, a measure that takes into account both the magnitude and duration of the stance phase, may provide more comprehensive information. This study directly compared the abilities of peak knee adduction moment and knee adduction moment impulse to distinguish between knee osteoarthritis severities.

Methods

169 participants with medial knee osteoarthritis completed radiographic and magnetic resonance imaging, the Western Ontario and McMaster Universities Arthritis Index to assess pain and a three-dimensional gait analysis. Participants were classified using four dichotomous classifications: Kellgren–Lawrence grading, alignment, medial tibiofemoral bone marrow lesions, and pain.

Findings

When using Kellgren–Lawrence grade and alignment classifications, the area under the receiver operator curves were significantly greater for knee adduction moment impulse than for peak knee adduction moment. Based on analysis of covariance, knee adduction moment impulse was significantly different between Kellgren–Lawrence grade and alignment groups while peak knee adduction moment was not significantly different. Both peak knee adduction moment and knee adduction moment impulse distinguished between bone marrow lesion severities while neither measure was significantly different between pain severity groups.

Interpretations

Findings suggest knee adduction moment impulse is more sensitive at distinguishing between disease severities and may provide more comprehensive information on medial knee joint loading. Future studies investigating biomechanics of knee osteoarthritis should include knee adduction moment impulse in conjunction with peak knee adduction moment.     

Longitudinal evidence links joint level mechanics and muscle activation patterns to 3-year medial joint space narrowing

BackgroundIt is currently not known if there are different mechanical factors involved in accelerated rates of knee osteoarthritis structural progression. Data regarding the role of the transverse plane moment along with the contributions to joint loading from muscle activity, a primary contributor to the joint loading environment, is not well represented in the current literature on knee OA radiographic progression. The objective of this study was to understand if a 3-year end point corroborates what has been shown for longer term radiographic progression or provides more insight into factors that may be implicated in more accelerated radiographic progression than those shown previously.Methods52 participants visited the Dynamics of Human Motion laboratory at baseline for three-dimensional, self-selected speed over ground walking gait analysis. Differences in magnitude and patterns of 3D knee moments and electromyography waveforms between participants who progressed radiographically from those that did not were compared using t-tests (P < 0.05).FindingsFeatures of the frontal and transverse plane knee moments along with muscle activation patterns for the lateral gastrocnemius and lateral hamstrings differentiated the progression group from the non-progression group at baseline.InterpretationIn general, the walking gait biomechanics of the progression group in this 3-year radiographic study aligned well with previously reported characteristics of diagnosed or symptomatic osteoarthritis. The higher rotation moment range during stance found with the progression group is a novel finding that points to a need to better understand torsional joint loading and its implications for loading of the knee joint tissues.