The role of muscle weakness in the pathogenesis of osteoarthritis

Genetic link between depression and musculoskeletal disorders: insights from Mendelian randomization analysis

Background

The association between depression and musculoskeletal diseases has long been a subject of contentious debate. However, the causal relationship between the two remains uncertain. This study employs a two-sample Mendelian randomization (MR) analysis to investigate the causality between depression and six musculoskeletal diseases.

Methods

In this study, we performed MR analysis to systematically explore the causal relationship between depression and six musculoskeletal disorders. Single nucleotide polymorphisms (SNPs) that are linked to depression were employed as instrumental variables. To ensure robust and reliable conclusions, multiple analytical approaches were utilized, including inverse variance weighting(IVW), weighted median, and MR-Egger regression. Additionally, sensitivity analysis methods such as the MR-Egger intercept test, Cochran's Q test, leave-one-out analysis, and funnel plot were employed.

Results

Our MR analysis revealed a significant association between depression and cervical spondylosis (depression: OR 1.003, 95% CI 1.002-1.005, P = 8.32E-05; major depressive disorder: OR 1.003, 95% CI 1.001-1.005, P = 0.0052). Furthermore, a strong correlation was noted between major depressive disorder (MDD) and knee osteoarthritis (KOA) (OR 1.299, 95% CI 1.154-1.463, P = 1.50E-5). Sensitivity analysis confirmed the robustness of these findings. Our independent validation study also corroborated these results.

Conclusion

The MR analysis conducted in this study provides evidence supporting a genetic link between depression and cervical spondylosis, as well as KOA. Targeted interventions to manage depression in susceptible populations may contribute to lowering the risk of cervical spondylosis and KOA in these cohorts.

Relationship of the weaknesses of knee- and hip-spanning muscles with knee compression forces during stair ascent and descent

BACKGROUND

The musculoskeletal models have been improved to estimate accurate knee compression force (KCF) and have been used to reveal the causal relationship between KCF and muscle weakness. Previous studies have explored how muscle weakness influences the KCF during gait; however, the influence of muscle weakness is possibly larger during activities that require deeper knee flexion (e.g., stair ambulation) than other activities (e.g., gait) because of the small knee contact area of articular surfaces.

RESEARCH QUESTION

To explore how muscle weakness influences the KCF during stair ambulation.

METHODS

Ten young adults performed stair ascent and descent tasks at a comfortable speed. Based on a previous study, we created muscle weakness models of rectus femoris (RF), vastus muscles (VAS), gluteus medius (Gmed), and gluteus maximus (Gmax), and the medial and lateral KCF (KCFmed and KCFlat) during stair ambulation were calculated.

RESULTS

Similar to the gait, the Gmed weakness increased KCFmed and decreased KCFlat during stair ascent and descent. Whereas, unlike the gait, the Gmax weakness increased KCFmed during stair ascent and the VAS weakness decreased KCFmed and KCFlat during stair ascent and descent. Moreover, the percentage changes in KCF were similar (or large) during stair ambulation compared with those during gait.

SIGNIFICANCE

Considering the KCF alterations caused by each muscle weakness, the weaknesses in Gmax and Gmed might lead to cartilage loss and pain in the knee, and the VAS weakness might lead to low stability of the knee. The symptom during stair ambulation might help precisely identify the muscle requiring rehabilitation.

Balancing act: Unraveling the link between muscle strength, proprioception, and stability in unilateral hip osteoarthritis

The objectives of this study are to compare hip muscle strength, hip joint proprioception, and functional balance between individuals with unilateral hip OA and asymptomatic individuals and to examine the relationships among these variables in the hip OA population. In a prospective cross-sectional study, 122 participants (unilateral Hip OA: n = 56, asymptomatic: n = 56) were assessed at the CAMS/KKU musculoskeletal Physical Therapy laboratory. Ethical standards were upheld throughout the research, with informed consent obtained. Hip muscle strength was measured using a hand-held dynamometer, hip joint proprioception with a digital inclinometer, and functional balance using the Berg Balance Scale (BBS) and Timed Up and Go (TUG) test. Hip OA individuals exhibited significantly lower muscle strength and proprioceptive accuracy, and poorer functional balance than controls (p < 0.003). Correlation analyses revealed a positive correlation between muscle strength and BBS scores (r = 0.38 to 0.42) and a negative correlation with TUG test times (r = -0.36 to -0.41). Hip joint reposition sense (JRS) in flexion showed a negative correlation with balance (r = -0.46), while JRS in abduction was positively correlated (r = 0.46). The study highlights the clinical importance of muscle strength and proprioception in functional balance among individuals with unilateral hip OA. The results support the incorporation of muscle strengthening and proprioceptive training in interventions to improve balance and mobility in this population.

Osteoarthritis

The clinical appearance and radiological pattern of osteoarthritis have been identified in the skeletons of dinosaurs some 50-70 million years old, and in Egyptian mummies, and in ancient skeletons in England. Osteoarthritis patterns of joint involvement, often referred to as primary osteoarthritis, can be seen in the hands, spinal facet joints, hips, knees and feet, but can also be termed secondary osteoarthritis when seen in any joint that has had trauma, sepsis, surgery or metabolic insult. The prevalence of osteoarthritis increases with age. The histology and pathophysiology both demonstrate an inflammatory process. While there have been studies of genetic predisposition, the basic cause of primary osteoarthritis has not been determined.

Exercise-induced fatigue affects knee proprioceptive acuity and quadriceps neuromuscular function more in patients with ACL reconstruction or meniscus surgery than in healthy individuals

PURPOSE

To observe how knee proprioceptive acuity and quadriceps neuromuscular function change during and after repeated isokinetic knee-extension exercise in patients with anterior cruciate ligament reconstruction (ACLR) or meniscus surgery.

METHODS

Patients with ACLR or meniscus surgery and matched controls (n = 19 in each group) performed knee-flexion replication at 15° and 75°, and quadriceps peak torque (PT), central activation ratio (CAR) and rate of torque development (RTD) at baseline and immediately after every five sets of isokinetic knee-extension exercise (times 1-5).

RESULTS

Compared to the baseline, the ACLR and control groups displayed errors in knee-flexion replication at 75° only at time 5 (115.9-155.6%; p ≤ 0.04, d ≥ 0.97), whereas the meniscus surgery group exhibited errors at all time points (142.5-265.6%; p ≤ 0.0003, d ≥ 1.4). Significant percentage reductions in quadriceps CAR were observed between times 4 and 5 in the ACLR group (-5.8%; p = 0.0002, d = 0.96), but not in the meniscus surgery (-1.4%; n.s.) and control (0.1%; n.s.) groups. Significant percentage reductions in quadriceps RTD were observed between times 4 and 5 in the ACLR (-24.2%; p = 0.007, d = 0.99) and meniscus surgery (-23.0%; p = 0.01, d = 0.85) groups, but not in the control group (-0.2%; n.s.).

CONCLUSION

Patients with ACLR or meniscus surgery displayed a greater loss in knee proprioceptive acuity and quadriceps neuromuscular function during and after exercise than healthy individuals. Evidence-based interventions to enhance exercise-induced fatigue resistance should be implemented following ACLR or meniscus surgery, aiming to prevent proprioceptive and neuromuscular changes within the knee joint and quadriceps.

LEVEL OF EVIDENCE

III.

A self-managed exercise therapy program for wrist osteoarthritis: study protocol for a randomized controlled trial

BACKGROUND

Post-traumatic wrist osteoarthritis (OA) can eventually lead to pain, muscular weakness, and stiffness of the wrist, which can affect the function of the entire upper limb and reduce the quality of life. Although there is strong evidence that all patients with OA should be offered adequate education and exercises as a first-line treatment, an effective self-management program, including structured education and therapeutic exercises, has not yet been introduced for individuals with wrist OA. This trial aims to evaluate the effectiveness of an exercise therapy program with joint protective strategies to improve neuromuscular control (intervention group) compared to a training program with range of motion exercises (control group).

METHODS

This is a single-blinded randomized controlled trial (RCT) with two treatment arms in patients with symptomatic and radiographically confirmed wrist OA. The trial will be conducted at a hand surgery department. The participants will be randomly assigned either to a neuromuscular exercise therapy program or to a training program with range of motion exercises only. Participants in both groups will receive a wrist orthosis and structured education on wrist anatomy, pathophysiology, and joint protective self-management strategies. The programs consist of home exercises that will be performed twice a day for 12 weeks. The Patient-Rated Wrist Evaluation (PRWE) is the primary outcome measure of pain and function. Wrist range of motion (ROM), grip strength, the Numeric Pain Rating scale (NPRS), Disabilities of the Arm, Shoulder, and Hand (DASH), the General Self-Efficacy Scale (GSES), Global Rating of Change (GROC), and conversion to surgery are the secondary measures of outcome. Assessments will be performed at baseline and at 3, 6, and 12 months after baseline by a blinded assessor.

DISCUSSION

The upcoming results from this trial may add new knowledge about the effectiveness of a self-managed exercise therapy program on pain and function for individuals with wrist OA. If the present self-management program proves to be effective, it can redefine current treatment strategies and may be implemented in wrist OA treatment protocols.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05367817. Retrospectively registered on 27 April 2022. https://clinicaltrials.gov .

The surgical destabilization of the abductor muscle leads to development of instability-associated hip osteoarthritis in mice

Osteoarthritis (OA) of the hip is a common and debilitating painful joint disease. However, there is paucity of surgically induced hip OA models in small animals that allow scientists to study the onset and progression of the disease. A growing body of evidence indicates a positive association between periarticular myotendinous pathology and the development of hip OA. Thus, in the current study, we aimed to establish a novel mouse instability-associated hip OA model via selective injury of the abductor complex around the hip joint. C57BL6/J mice were randomized to sham surgery or abductor injury, in which the myotendinous insertion at the third trochanter and greater trochanter were surgically detached. Mice were allowed free active movement until they were sacrificed at either 3 weeks or 20 weeks post-injury. Histologic analyses and immunohistochemical staining of the femoral head articular cartilage were performed, along with microCT (µCT) analysis to assess subchondral bone remodeling. We observed that mice receiving abductor injury exhibited significantly increased instability-associated OA severity with loss of proteoglycan and type II collagen staining compared to sham control mice at 20 weeks post-surgery, while comparable matrix metalloproteinase 13 expression was observed between injury and sham groups. No significant differences in subchondral bone remodeling were found after 3 or 20 weeks following injury. Our study further supports the link between abductor dysfunction and the development of instability-associated hip OA. Importantly, this novel surgically induced hip OA mouse model may provide a valuable tool for future investigations into the pathogenesis and treatment of hip OA.

Unilateral transfemoral osseointegrated prostheses improve joint loading during walking

People with unilateral transfemoral amputation using socket prostheses are at increased risk for developing osteoarthritis in both the residual hip and intact lower-limb joints. Osseointegrated prostheses are a surgical alternative to socket prostheses that directly attach to the residual femur via a bone-anchored implant, however their multi-joint loading effect is largely unknown. Our objective was to establish how osseointegrated prostheses influence joint loading during walking. Motion capture data (kinematics, ground reaction forces) were collected from 12 participants at baseline, with socket prostheses, and 12-months after prosthesis osseointegration during overground walking at self-selected speeds. Subject-specific musculoskeletal models were developed at each timepoint relative to osseointegration. Internal joint moments were calculated using inverse dynamics, muscle and joint reaction forces (JRFs) were estimated with static optimization. Changes in internal joint moments, JRFs, and joint loading-symmetry were compared using statistical parametric mapping (p≤ 0.05) before and after osseointegration. Amputated limb hip flexion moments and anterior JRFs decreased during terminal stance (p = 0.002, <0.001; respectively), while amputated limb hip abduction moments increased during mid-stance (p < 0.001), amputated hip rotation moment changed from internal to external throughout early stance (p < 0.001). Intact limb hip extension and knee flexion moments (p = 0.028, 0.032; respectively), superior and resultant knee JRFs (p = 0.046, 0.049; respectively) decreased during the loading response following prosthesis osseointegration. These results may indicate that the direct loading transmission of these novel prostheses create a more typical mechanical environment in bilateral joints, which is comparable with loading observed in able-bodied individuals and could decrease the risk of development or progression of osteoarthritis.

Assessment of the Impact of Physical Activity on the Musculoskeletal System in Early Degenerative Knee Joint Lesions in an Animal Model

Osteoarthritis (OA) is one of the most prevalent diseases of the osteoarticular system. Progressive destruction of joints is accompanied by development of pathological changes in the muscle tissue, i.e., weakening, atrophy, and remodelling (sarcopenia). The aim of the present study is to assess the impact of physical activity on the musculoskeletal system in an animal model of early degenerative lesions in the knee joint. The study involved 30 male Wistar rats. The animals were allocated to three subgroups of 10 animals each. Each animal from the three subgroups received sodium iodoacetate by injection into the patellar ligament of the right knee joint, whereas saline was administered through the patellar ligament in the left knee joint. The rats in the first group were stimulated to exercise on a treadmill. The animals in the second group were allowed to lead a natural lifestyle (no treadmill stimulation). In the third group, all parts of the right hind limb muscle were injected with Clostridium botulinum toxin type A. The study demonstrated that, compared to the active rats, bone density in the immobilised rats decreased, as indicated by the densitometric assessment of the whole body and the examination of rats' hind limbs and knee joints alone. This clearly evidenced the impact of physical activity on bone mineralisation. The weight of both fat and muscle tissues in the physically inactive rats was reduced. Additionally, the adipose tissue had higher weight in the entire right hind limbs, where monoiodoacetic acid was administered to the knee joint. The animal model clearly showed the importance of physical activity in the early stages of OA, as it slows down the process of joint destruction, bone atrophy, and muscle wasting, whereas physical inactivity contributes to progression of generalised changes in the musculoskeletal system.

Risk of total hip arthroplasty after elite sport: linking 3304 former world-class athletes with the Norwegian Arthroplasty Register

OBJECTIVES

At present, there is no cure for osteoarthritis (OA), but severe hip joint degeneration can require total hip arthroplasty (THA). The literature on OA after elite sport is limited. We hypothesise that elite athletic activity increases the risk of receiving a THA later in life.

METHODS

We linked a cohort of former Norwegian world-class athletes (1402 females and 1902 males, active 1936-2006) to the Norwegian Arthroplasty Register (THA performed 1987-2020). We used standardised incidence ratio (SIR), one-minus Kaplan-Meier and relative Cox regression (relative HR, RHR), with 95% CIs, and funnel plots at age 75, to assess THA risk for different sport disciplines, joint impact categories of sport disciplines and sex. The risk of THA for the corresponding general Norwegian population was used as reference.

RESULTS

We found an overall increased risk for THA for the former elite athletes (SIR 2.11, 95% CI 1.82 to 2.40) at age 75 years, compared with the general population. THA risk at age 75 years was 11.6% for female athletes and 8.3% for male athletes. SIR was 1.90 (95% CI 1.49 to 2.31) for female and 2.28 (95% CI 1.87 to 2.70) for male athletes. Among males, high joint impact sport disciplines were associated with increased risk compared with low-impact sport disciplines (RHR 1.81, 95% CI 1.06 to 3.08, p=0.029).

CONCLUSION

Having been an elite athlete was associated with a doubling of THA risk compared with the general population for both sexes. High joint impact sport disciplines were associated with subsequent THA for male athletes.

Effects of a targeted resistance intervention compared to a sham intervention on gluteal muscle hypertrophy, fatty infiltration and strength in people with hip osteoarthritis: analysis of secondary outcomes from a randomised clinical trial

Background

People with hip osteoarthritis are typically offered a combination of education and exercise to address muscle atrophy and weakness. Limited evidence exists to assess the efficacy of exercise programs on muscle structure or function in this population. The aim of this study was to evaluate the effects of targeted resistance exercise on gluteal muscle hypertrophy and strength in people with mild-to-moderate hip osteoarthritis.

Methods

Twenty-seven participants with radiologically confirmed hip osteoarthritis recruited from a single site of a multi-site, double-blind clinical trial were randomly allocated to receive a 12-week targeted gluteal intervention or sham intervention. Magnetic resonance imaging and hand-held dynamometry were used to determine change in gluteal muscle volume, fatty infiltration and hip muscle strength. For gluteal muscle volume and strength outcomes mixed model analyses of variance (ANOVA) were conducted. A general linear model (ANOVA) analysis with fixed effects parameter estimates was used to assess the impact of sex on gluteal muscle size and strength of the affected limb only. For muscle fat index a mixed method ANOVA was used to assess the differences between groups and over time.

Results

In the targeted intervention group, gluteus minimus volume increased from baseline to post-intervention in both limbs (pooled mean difference: 0.06 cm³/kg, 95% confidence interval: 0.01 to 0.11) while no change occurred in the sham group (time x group effect: P = 0.025). Gluteus medius, gluteus maximus and tensor fascia lata volume did not change significantly over time. Hip strength (abduction, adduction, flexion, extension, external and internal rotation) improved similarly in both groups (time main effect: P ≤ 0.042). There was a consistent, albeit non-significant, pattern of reduced fatty infiltration after the targeted intervention.

Conclusion

Targeted resistance exercise resulted in gluteus minimus hypertrophy, but improvements in hip strength occurred in both groups. Clinicians delivering hip osteoarthritis rehabilitation programs might consider implementing a targeted exercise program to attenuate disease associated changes within gluteal muscles.

Trial registration

Australian New Zealand Clinical Trials Registry, ID: ACTRN12617000970347. Registered prospectively on 5 July 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05907-4.

A Novel Mobile App-based Neuromuscular Electrical Stimulation Therapy for the Management of Knee Osteoarthritis: Results From an Extension Study of a Randomized, Double-blind, Sham-controlled, Multicenter Trial

Mobile app-based neuromuscular electrical stimulation (NMES) is a promising treatment of knee osteoarthritis as previously demonstrated in a 12-week, randomized, double-blind, sham-controlled, multicenter trial (parent study).

Knee joint biomechanics during gait improve from 3 to 6 months after anterior cruciate ligament reconstruction

Gait alterations after anterior cruciate ligament reconstruction (ACLR) are commonly reported and have been linked to posttraumatic osteoarthritis development. While knee gait alterations have been studied at several time points after ACLR, little is known about how these biomechanical variables change earlier than 6 months after surgery, nor is much known about how they differ over the entire stance phase of gait. The purpose of this study was to examine knee gait biomechanical variables over their entire movement pattern through stance at both 3 and 6 months after ACLR and to study the progression of interlimb asymmetry between the two postoperative time points. Thirty-five individuals underwent motion analysis during overground walking 3 (3.2 ± 0.5) and 6 (6.4 ± 0.7) months after ACLR. Knee biomechanical variables were compared between limbs and across time points through 100% of stance using statistical parametric mapping; this included a 2 × 2 (Limb × Time) repeated measures analysis of variance and two-tailed t-tests. Smaller knee joint angles, moments, extensor forces, and medial compartment forces were present in the involved versus uninvolved limb. Interlimb asymmetries were present at both time points but were less prevalent at 6 months. The uninvolved limb's biomechanical variables stayed relatively consistent over time, while the involved limb's trended toward that of the uninvolved limb. Statement of Clinical Significance: Interventions to correct asymmetrical gait patterns after ACLR may need to occur early after surgery and may need to focus on multiple parts of stance phase.

Biomechanical compensations during a stand-to-sit maneuver using transfemoral osseointegrated prostheses: A case series

BACKGROUND

Patients with transfemoral amputation and socket prostheses are at a heightened risk of developing musculoskeletal overuse injuries, commonly due to altered joint biomechanics. Osseointegrated prostheses, which involve direct anchorage of the prosthesis to the residual limb through a bone anchored prosthesis, are a novel alternative to sockets yet their biomechanical effect is largely unknown.

METHODS

Four patients scheduled to undergo unilateral transfemoral prosthesis osseointegration completed two data collections (baseline with socket prosthesis and 12-months after prosthesis osseointegration) in which whole-body kinematics and ground reaction forces were collected during stand-to-sit tasks. Trunk, pelvis, and hip kinematics, and the surrounding muscle forces, were calculated using subject-specific musculoskeletal models developed in OpenSim. Peak joint angles and muscle forces were compared between timepoints using Cohen's d effect sizes.

FINDINGS

Compared to baseline with socket prostheses, patients with osseointegrated prostheses demonstrated reduced lateral trunk bending (d = 1.46), pelvic obliquity (d = 1.09), and rotation (d = 1.77) toward the amputated limb during the stand to sit task. This was accompanied by increased amputated limb hip flexor, abductor, and rotator muscle forces (d> > 0.8).

INTERPRETATION

Improved lumbopelvic movement patterns and stabilizing muscle forces when using an osseointegrated prosthesis indicate that this novel prosthesis type likely reduces the risk of the development and/or progression of overuse injuries, such as low back pain and osteoarthritis. We attribute the increased muscle hip muscle forces to the increased load transmission between the osseointegrated prosthesis and residual limb, which allows a greater eccentric ability of the amputated limb to control lowering during the stand-to-sit task.

Knee extensor functional demand in individuals with knee osteoarthritis

BACKGROUND

Knee extensor (KE) weakness is commonly exhibited in individuals with knee osteoarthritis (KOA) and may contribute to disability due an increased muscle functional demand and resulting compensatory gait strategies during locomotion. Muscle functional demand is defined as the percentage of maximal strength that is used during a task.

RESEARCH QUESTION

The study aim was to quantify KE functional demand in KOA, the impact of walking speed and the relationships with the relative joint contribution to total limb work.

METHODS

Fourteen individuals with symptomatic KOA underwent gait analysis at preferred and faster speeds and isokinetic dynamometry for KE maximum voluntary isometric torque. The KE functional demand as well as the relative and peak joint work and powers were calculated. Paired samples t-test was used to compare functional demand and relative work between speeds and Pearson's correlation was used to assess the relationship between relative work and functional demand values (α = 0.05).

RESULTS

The KE functional demand was 36.0 ± 15.7 % for the preferred speed and significantly higher at 49.8 ± 16.1 % for the faster speed, (t(13) = -5.45, p .05). Knee flexion moment was also significantly higher for the faster speed (t(13) = -5.54, p .001). There were significant relationships between fast speed functional demand and relative ankle negative power (r = -0.57) and relative ankle positive work (r = 0.66), (all p .05).

SIGNIFICANCE

The results suggest that as functional demand nears or exceeds 50 % of the muscle capacity individuals with KOA reduce the relative effort at the knee and use an ankle-based compensation strategy to meet task demands.

Rate of force development in the quadriceps of individuals with severe knee osteoarthritis: A preliminary cross-sectional study

Knee osteoarthritis (KOA) is a leading cause of knee pain and disability due to irreversible cartilage degeneration. Previous studies have not identified modifiable risk factors for KOA. In this preliminary cross-sectional study, we aimed to test the following hypotheses: individuals with severe KOA would have a significantly lower quadriceps rate of force development (RFD) than individuals with early KOA, and the decrease in quadriceps RFD would be greater than the decrease in maximum quadriceps strength in individuals with severe KOA. The maximum isometric strength of the quadriceps was assessed in individuals with mild (Kellgren and Lawrence [K&L] grade 1–2) and severe KOA (K&L grade 3–4) using a handheld dynamometer. The RFD was analyzed at 200 ms from torque onset and normalized to the body mass and maximum voluntary isometric contraction torque. To test whether the quadriceps RFD was lowered and whether the lower in the quadriceps RFD was greater than the lower in maximum quadriceps strength in individuals with severe knee OA, the Mann–Whitney U-test and analysis of covariance were performed, respectively. The effect size (ES) based on Hedges’ g with a 95% confidence interval (CI) was calculated for the quadriceps RFD and maximum quadriceps strength. Sixty-six participants were analyzed. Individuals with severe KOA displayed significantly lower quadriceps RFD (p = 0.009), the lower being greater than the lower in maximum quadriceps strength (between-group difference, ES: 0.88, -1.07 vs. 0.06, -0.22). Our results suggest that a decreased quadriceps RFD is a modifiable risk factor for progressive KOA. Our finding could help in the early detection and prevention of severe KOA.

Reliability of hip joint position sense tests using a clinically applicable measurement tool in elderly participants with unilateral hip osteoarthritis

Hip joint proprioception is vital in maintaining posture and stability in elderly individuals. Examining hip joint position sense (JPS) using reliable tools is important in contemporary clinical practice. The objective of this study is to evaluate the intra-rater and inter-rater reliability of hip JPS tests using a clinically applicable measurement tool in elderly individuals with unilateral hip osteoarthritis (OA). Sixty-two individuals (mean age = 67.5 years) diagnosed with unilateral hip OA participated in this study. The JPS tests were evaluated using a digital inclinometer in hip flexion and abduction directions. The absolute difference between target and reproduced angle (repositioning error) in degrees was taken to measure JPS accuracy. The intraclass correlation coefficient (ICC (2.k), was used to assess the reliability. The Intra rater-reliability for hip JPS tests showed very good agreement in the lying position (hip flexion-ICC = 0.88–0.92; standard error of measurement (SEM) = 0.06–0.07, hip abduction-ICC = 0.89–0.91; SEM = 0.06–0.07) and good agreement in the standing position (hip flexion-ICC = 0.69–0.72; SEM = 0.07, hip abduction-ICC = 0.66–0.69; SEM = 0.06–0.08). Likewise, inter-rater reliability for hip JPS tests demonstrated very good agreement in the lying position (hip flexion-ICC = 0.87–0.89; SEM = 0.06–0.07, hip abduction-ICC = 0.87–0.91; SEM = 0.07) and good agreement in the standing position (hip flexion-ICC = 0.64–0.66; SEM = 0.08, hip abduction-ICC = 0.60–0.72; SEM = 0.06–0.09). The results support the use of hip JPS tests in clinical practice and should be incorporated in assessing and managing elderly participants with hip OA.

Estimates of voluntary activation in individuals with anterior cruciate ligament reconstruction: Effects of type of stimulator, number of stimuli, and quantification technique

BACKGROUND

Accurate quantification of voluntary activation is important for understanding the extent of quadriceps dysfunction in individuals with anterior cruciate ligament reconstruction (ACLR). Voluntary activation has been quantified using both percent activation derived from the interpolated twitch technique and central activation ratio (CAR) derived from the burst superimposition technique, as well as by using different types of electrical stimulators and pulse train conditions. However, it is unclear how these parameters affect voluntary activation estimates in individuals with ACLR. This study was performed to fill this important knowledge gap in the anterior cruciate ligament literature.

METHODS

Quadriceps strength and voluntary activation were examined in 18 ACLR participants (12 quadriceps/patellar tendon graft, 6 hamstring tendon graft; time since ACLR: 1.06 ± 0.82 years, mean ±  SD) at 90° of knee flexion using 2 stimulators (Digitimer and Grass) and pulse train conditions (3-pulse and 10-pulse). Voluntary activation was quantified by calculating both CAR and percent activation.

RESULTS

Results indicated that voluntary activation was significantly overestimated by CAR when compared with percent activation (p < 0.001). Voluntary activation estimates were not affected by pulse train conditions when using percent activation; however, 3-pulse stimuli resulted in greater overestimation than 10-pulse stimuli when using CAR (p = 0.003). Voluntary activation did not differ between stimulators (p > 0.05); however, the Digitimer evoked greater torque at rest than the Grass (p < 0.001).

CONCLUSION

These results indicate that percent activation derived from the interpolated twitch technique provides superior estimates of voluntary activation than CAR derived from burst superimposition and is less affected by pulse train conditions or stimulators in individuals with ACLR.

The three-dimensional quadriceps vector is most parallel to the spherical axis in Japanese varus osteoarthritic knees

BACKGROUND

The quadriceps femoris may be a reliable reference to proper alignment in total knee arthroplasty (TKA). We previously showed the quadriceps vector (QV) to be the most parallel to the spherical axis (SA-center hip to center medial condyle) for healthy knees. The purpose of this study was to determine whether the QV is the most parallel to the SA in knees with varus osteoarthritis (OA).

METHODS

CT imaging for 35 varus OA and 40 healthy Japanese knees was used to construct 3D models of the femur, patella and each quadriceps component for each subject. The QV was calculated using principal component analysis for direction and was compared with the relationship of the QV to the measurement axes of the lower extremity, including the anatomical, mechanical and spherical axes.

RESULTS

The direction of the QV for the OA knee group was different from that for the healthy knee group in 3D space (medio-lateral direction: women, p = 0.532, men, p = 0.540; antero-posterior direction: women, p = 0.141, men, p < 0.001). However, the angle of the QV in relation to measurement axes in the coronal plane was closest to the SA in both groups (around 1°), with no difference between the groups (women, p = 0.382, men, p = 0.943).

CONCLUSION

In the coronal plane, the SA most closely approximates the QV for both healthy and OA knees. The more posterior QV position in the 3D space may affect the patellofemoral joint.

A Mendelian randomization study on the role of serum parathyroid hormone and 25-hydroxyvitamin D in osteoarthritis

OBJECTIVE

Serum parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] have been demonstrated to be associated with pathogenesis and progression of osteoarthritis (OA). This study aimed to determine the potential causal relationship between serum PTH and 25(OH)D levels and risk of OA.

DESIGN

We applied the two-sample Mendelian randomization (MR) approach to estimate the causal roles of serum PTH and 25(OH)D on OA. The instrumental variables for serum PTH and 25(OH)D were derived from two large genome-wide association studies (GWAS), which included 29,155 and 79,366 individuals, respectively. Summary-level data for overall, hip and knee OA were extracted from a GWAS meta-analysis, including 455,221 individuals. All participants included in this study were from the European population.

RESULTS

An inverse association was observed between serum PTH levels and risk of OA (random-effects: Effect = 0.71; 95% CI: 0.54 to 0.92; fixed-effects: Effect = 0.71; 95% CI: 0.61 to 0.82). Stratified by site, serum PTH levels were found to be inversely associated with knee OA (random-effects: Effect = 0.53; 95% CI: 0.41 to 0.68; fixed-effects: Effect = 0.53; 95% CI: 0.41 to 0.68). However, there was no evidence of the causal effect of serum 25(OH)D levels on OA.

CONCLUSIONS

The present study indicates an inverse causal relationship between serum PTH concentrations and development of OA. Moreover, a site-specific association was also observed between serum PTH levels and knee OA. The potential mechanisms by which serum PTH affects OA need to be further investigated.

Joint position sense impairments in older adults with carpometacarpal osteoarthritis: A descriptive comparative study

STUDY DESIGN

This study has a descriptive-comparative, cross-sectional design.

INTRODUCTION

Sensorimotor (SM) impairments have been observed after common wrist and hand injuries such as distal radius fractures. However, there is a lack of research regarding SM impairments in patients with carpometacarpal (CMC) osteoarthritis (OA).

PURPOSE OF THE STUDY

This study sought to quantify proprioception deficits in older adults with CMC OA as compared with healthy adults using the joint position sense (JPS) test.

METHODS

The active JPS test was used to measure proprioception function in 29 thumbs with CMC OA and their 29 matched-control healthy counterparts. For comparison, participants with unilateral CMC OA were matched against themselves, whereas those with lateral CMC OA were age matched with a healthy participant. Data analysis was performed to compute the mean error of JPS; an unpaired t test was used to compare the mean error of the non-CMC OA group with the healthy control group.

RESULTS

The mean positional error measured from subjects with CMC OA was 9.53° compared with 1.32° for the age-matched healthy subjects. The effect size for the difference in means was D = 1.96.

CONCLUSIONS

Thumb SM impairments were found to be greater in subjects with CMC OA than in their healthy counterparts when using the JPS test to assess proprioception.

Knee pain in young adult women- associations with muscle strength, body composition and physical activity

BACKGROUND

Knee pain is studied mostly in older age groups, although in young adults it may be an indicator of future impaired musculoskeletal health. Therefore, the aim of this study was to examine the longitudinal association between knee pain and thigh muscle strength in young adult women and to explore the associations between muscle strength, body composition, physical activity and knee pain.

METHODS

The PEAK-25 cohort consists of women aged 25 at baseline (N=1064). At the 10-year follow-up n=728 attended for DXA-measured body composition and muscle strength assessment and n=797 answered the questionnaire on health and lifestyle. Independent samples t-test was used to compare women with and without knee pain, Spearman correlation was used to test the longitudinal association between strength and knee pain.

RESULTS

Knee pain was reported by one third of the women at follow-up (n=260, 33%), although physical activity levels were similar in those with and without pain (high level 50 vs 45 % (p= 0.18). Body composition differed, however. Women with knee pain had higher BMI (25.6 vs 24.1), fat mass index (9.2 vs 8.2) and % total body fat mass (34.7 vs 33.2). Simultaneously, they had lower % lean mass (total body 61.5 vs 62.8; legs 20.6 vs 21.0) and lower thigh muscle strength (extensors 184.9 vs 196.8, flexors 96.6 vs 100.9, p<0.05), but slightly higher hamstrings-to -quadriceps ratio (0.53 vs 0.51, p=0.04). Muscle strength at baseline weakly correlated with knee pain at follow-up (extensor r_s= -0.04; flexor -0.02, p>0.2). Overweight women had higher absolute thigh muscle strength, but lower weight-adjusted strength than normal weight women (p<0.001). Leg lean mass explained 26-34% of the variation in muscle strength and adjustment for physical activity level had little effect.

CONCLUSION

Knee pain is already common among women in their mid-thirties. Lower thigh muscle strength in the mid-twenties was not associated with future knee pain, however women with knee pain tended to have lower thigh muscle strength and a body composition of higher body fat combined with lower lean mass. Maintaining a healthy body composition and adequate thigh muscle strength may be beneficial for knee joint health.

Trunk movement compensation identified by inertial measurement units is associated with deficits in physical performance, muscle strength and functional capacity in people with hip osteoarthritis

BACKGROUND

Trunk movement compensation characterized as ipsilateral trunk lean and posterior rotation with respect to pelvis during stance phase of walking is common in people with hip osteoarthritis and a biomarker of deficits in physical function in older adults. However, the relationship between trunk movement compensation on deficits in physical performance, muscle strength and functional capacity is unknown.

METHODS

A cross-sectional study design was used. Two inertial measurement units were used to assess trunk movement compensation during the six-minute-walk-test. Knee extension, knee flexion and hip abduction strength were measured using hand-held dynamometer. Multivariate regression models, controlling for self-reported hip pain, were used to regress trunk movement compensation onto six-minute-walk-test and muscle strength measures. Pairwise t-tests were used to evaluate the difference trunk movement compensation has on functional capacity by comparing the first and last minute of the six-minute-walk-test.

FINDINGS

Thirty-five participants (63.3 ± 7.4 years, 57% male, 28.6 ± 4.5 kg/m²) were enrolled. Greater trunk movement compensation was related to poorer six-minute-walk-test (p = 0.03; r = -0.46). Greater hip abduction weakness was related to increased trunk movement compensation in both the sagittal (p = 0.05; r = -0.44) and frontal (p = 0.04; r = -0.38) planes. Participants demonstrated greater frontal plane trunk movement compensation during the last minute compared to the first minute of the six-minute-walk-test (p < 0.01).

INTERPRETATION

Trunk movement compensation, identified by inertial measure units, is a clinically relevant measure and has a moderate-to-strong relationship on deficits in physical performance, muscle strength and functional capacity. Inertial measurement units can be used as a practical means of measuring movement quality in the clinical setting.

Association of Sports Participation With Osteoarthritis: A Systematic Review and Meta-Analysis

Background:

The association between participating in sport and osteoarthritis is not fully understood.

Purpose:

To investigate the association between osteoarthritis and participating in sports not listed in previous reviews: American football, archery, baseball, bobsleigh, curling, handball, ice hockey, shooting, skeleton, speed skating, and wrestling.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

We searched 4 electronic databases and hand searched recent/in-press editions of relevant journals. The criteria for study selection were case-control studies, cohort studies, nested case-control studies, and randomized trials with a control group that included adults to examine the effect of exposure to any of the included sports on the development of osteoarthritis.

Results:

The search returned 6197 articles after deduplication. Nine studies were included in the final review, covering hip, knee, and ankle osteoarthritis. There were no studies covering archery, baseball, skeleton, speed skating, or curling. The 6 sports included in the review were analyzed as a collective; the results of the meta-analysis indicated that participation in the sports analyzed was associated with an increased risk of developing osteoarthritis of the hip (relative risk [RR] = 1.67 [95% confidence interval (CI), 1.15-2.41]; P = .04), knee (RR = 1.60 [95% CI, 1.23-2.08]; P < .001), and ankle (RR = 7.08 [95% CI, 1.24-40.51]; P = .03) as compared with controls. Meta-analysis suggested a significantly increased likelihood of developing hip osteoarthritis through participating in wrestling (RR = 1.78 [95% CI, 1.20-2.64]; P = .004) and ice hockey (RR = 1.70 [95% CI, 1.27-2.29]; P < .001), while there was no significant difference through participating in handball (RR = 2.50 [95% CI, 0.85-7.36]; P = .10). Likelihood of developing knee osteoarthritis was significantly increased in wrestling (RR = 2.22 [95% CI, 1.59-3.11]) and ice hockey (RR = 1.52 [95% CI, 1.18-1.96]; both P < .002). According to the meta-analysis, shooting did not have a significant effect on the RR of knee osteoarthritis as compared with other sports (RR = 0.43 [95% CI, 0.06-2.99]; P = .39).

Conclusion:

The likelihood of developing hip and knee osteoarthritis was increased for ice hockey and wrestling athletes, and the risk of developing hip osteoarthritis was increased for handball athletes. The study also found that participation in the sports examined, as a collective, resulted in an increased risk of developing hip, knee, and ankle osteoarthritis.

Is Thumb Proprioception Decreased in Patients With Trapeziometacarpal Joint Osteoarthritis?

Proprioception is thought to be essential for normal joint homeostasis, and its decreased function has been associated with an increased risk of joint diseases. However, only a few studies have been performed on the association between proprioceptive function in the trapeziometacarpal joint (TMCJ) and osteoarthritis. The purpose of this study was to compare TMCJ proprioceptive function in elderly women with radiographic TMCJ osteoarthritis relative to age-matched control women without osteoarthritis. We enrolled 19 women (mean age, 66 years) with symptomatic, radiographic Eaton and Littler grade 2, 3, and 4 TMCJ osteoarthritis and 19 age-matched control women without osteoarthritis. We evaluated thumb proprioception by using a joint-position reproduction test and compared the reposition error (RE) between the groups. We carried out a multivariate analysis for factors potentially associated with increased RE, such as age, body mass index, hand dominance, the presence of diabetes, pain level, and the presence of osteoarthritis. Also, a logistic regression analysis was performed for factors associated with the occurrence of TMCJ osteoarthritis. Patients with TMCJ osteoarthritis had greater RE than did the control patients in the joint-position reproduction test at 20°, 30°, and 40° of thumb palmar abduction. The multivariate analysis indicated that increased RE was associated with the presence of osteoarthritis, but not with the other factors assessed. The occurrence of TMCJ osteoarthritis was associated with increased RE at 20°, 30°, and 40° of thumb palmar abduction. This study showed that decreased proprioceptive function was associated with the presence of osteoarthritis in the TMCJ, although the causality remains unknown. Further studies on the role of proprioception in the pathogenesis of TMCJ osteoarthritis and the potential role of its training for disease prevention or treatment are required.

Meta-analysis on the association between knee extensor strength and structural changes of knee osteoarthritis

This study aimed to perform a meta-analysis to evaluate whether knee extensor (KE) strength weakness was associated with increased structural worsening in knee osteoarthritis (KOA) including joint space narrowing (JSN) and cartilage loss. PubMed, Embase, Scopus, ScienceDirect, Web of Science, and Cochrane library were searched from their inception to May 2020, to identify eligible studies. Odds ratios (ORs) accompanied by 95% confidence intervals (CIs) were calculated for the relationship between KE strength and outcomes. Totally eleven longitudinal studies were included. The pooled crude OR indicated no significant association between KE strength weakness and KOA progression of JSN (OR: 1.13, 95% CI: 0.90, 1.42), and this result duplicated after confounders were adjusted (OR: 1.10, 95% CI: 0.87, 1.39). Subgroup analysis showed the association remained non-significant in sex-specific outcomes and subsets of neutral and malaligned knees, but there was a trend toward increased risk of JSN progression in female knees with low strength (OR: 1.24, 95% CI: 0.87, 1.76, I² = 82%). The pooled crude OR showed that KE strength weakness was associated with increased risk of cartilage loss (OR:1.43, 95% CI: 1.05, 1.95). After adjustment, we found a non-significant trend that low KE strength could increase the risk of cartilage loss (OR: 1.25, 95% CI: 0.95, 1.64), and this trend was separately observed in tibiofemoral or patellofemoral compartments. This meta-analysis suggested that KE strength weakness was not significantly associated with an increased risk of radiographic structural KOA progression in patients with KOA or known risk factors for KOA. However, there was a trend that women with weaker KE strength displayed a higher risk of JSN worsening and that KE strength weakness had an association with an increased risk of cartilage damage. Key points • Knee extensor strength weakness is not significantly associated with an increased risk of radiographic structural KOA progression in patients with or at risk of knee osteoarthritis. • There is a non-significant trend toward an increased risk of JSN progression in female knees with low knee extensor strength. • There is a trend that low KE strength can increase the risk of cartilage loss no matter in tibiofemoral or patellofemoral compartments, but it's not significant.

Knee Extensor and Flexor Torque Variability During Maximal Strength Testing and Change in Knee Pain and Physical Function at 60-Mo Follow-Up: The Multicenter Osteoarthritis Study (MOST)

ABSTRACT

As the population ages, there is a growing burden owing to musculoskeletal diseases, such as knee osteoarthritis, and subsequent functional decline. In the absence of a cure, there is a need to identify factors amenable to intervention to prevent or slow this process. The Multicenter Osteoarthritis Study cohort was developed for this purpose. In this study, associations between variability in peak knee flexor and extensor torque at baseline and worsening of pain and physical function over the subsequent 60 mos were assessed in a cohort of 2680 participants. The highest quartile of baseline knee flexor torque variability was found to be associated longitudinally with worsening pain (fourth quartile ß estimate, mean ± SE, 0.49 ± 0.19; P = 0.0115; with R2 = 0.28 and P for trend across quartiles = 0.0370) and physical function scores (fourth quartile ß estimate, mean ± SE, 1.39 ± 0.64; P = 0.0296; with R2 = 0.25 and P for trend across quartiles = 0.0371), after adjusting for baseline knee osteoarthritis and maximum knee flexor torque. There were no associations between baseline knee extensor torque and worsening pain or physical function by 60 mos. The presence of greater variability in maximum knee flexor strength may identify patients who may benefit from therapies aimed at preventing worsening knee pain and physical function.

Quadriceps Strength Symmetry Does Not Modify Gait Mechanics After Anterior Cruciate Ligament Reconstruction, Rehabilitation, and Return-to-Sport Training

BACKGROUND

After anterior cruciate ligament (ACL) reconstruction (ACLR), biomechanical asymmetries during gait are highly prevalent, persistent, and linked to posttraumatic knee osteoarthritis. Quadriceps strength is an important clinical measure associated with preoperative gait asymmetries and postoperative function and is a primary criterion for return-to-sport clearance. Evidence relating symmetry in quadriceps strength with gait biomechanics is limited to preoperative and early rehabilitation time points before return-to-sport training.

PURPOSE/HYPOTHESIS

The purpose was to determine the relationship between symmetry in isometric quadriceps strength and gait biomechanics after return-to-sport training in athletes after ACLR. We hypothesized that as quadriceps strength symmetry increases, athletes will demonstrate more symmetric knee joint biomechanics, including tibiofemoral joint loading during gait.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Of 79 athletes enrolled in the ACL-SPORTS Trial, 76 were participants in this study after completing postoperative rehabilitation and 10 return-to-sport training sessions (mean ± SD, 7.1 ± 2.0 months after ACLR). All participants completed biomechanical walking gait analysis and isometric quadriceps strength assessment using an electromechanical dynamometer. Quadriceps strength was calculated using a limb symmetry index (involved limb value / uninvolved limb value × 100). The biomechanical variables of interest included peak knee flexion angle, peak knee internal extension moment, sagittal plane knee excursion at weight acceptance and midstance, quadriceps muscle force at peak knee flexion angle, and peak medial compartment contact force. Spearman rank correlation (ρ) coefficients were used to determine the relationship between limb symmetry indexes in quadriceps strength and each biomechanical variable; alpha was set to .05.

RESULTS

Of the 76 participants, 27 (35%) demonstrated asymmetries in quadriceps strength, defined by quadriceps strength symmetry <90% (n = 23) or >110% (n = 4) (range, 56.9%-131.7%). For the biomechanical variables of interest, 67% demonstrated asymmetry in peak knee flexion angle; 68% and 83% in knee excursion during weight acceptance and midstance, respectively; 74% in internal peak knee extension moment; 57% in medial compartment contact force; and 74% in quadriceps muscle force. There were no significant correlations between quadriceps strength index and limb symmetry indexes for any biomechanical variable after return-to-sport training (P > .129).

CONCLUSION

Among those who completed return-to-sport training after ACLR, subsequent quadriceps strength symmetry was not correlated with the persistent asymmetries in gait biomechanics. After a threshold of quadriceps strength is reached, restoring strength alone may not ameliorate gait asymmetries, and current clinical interventions and return-to-sport training may not adequately target gait.

Quadriceps strength to body weight ratio is a significant indicator for initiating jogging after anterior cruciate ligament reconstruction

BACKGROUND

Quadriceps strength recovery after anterior cruciate ligament (ACL) reconstruction is an important criterion for progress in rehabilitation and return to sports. The purpose of this study was to determine whether quadriceps strength to body weight ratio (QS/BW) is a significant indicator for initiating jogging after ACL reconstruction.

METHODS

Isokinetic quadriceps strength at 60°/s was measured and a jogging trial was completed 3 months after ACL reconstruction with hamstring tendon autograft in 83 patients (36 male, 47 female; mean age, 26.6 ± 12.4 years). Based on the jogging trial results, patients were assigned to either a successful jogging group (mean velocity ≥ 9 km/h) or an unsuccessful jogging group (mean velocity < 9 km/h). The association between QS/BW and successful jogging after surgery was investigated by multivariate logistic regression analysis and the cut-off value was determined by receiver operating characteristic analysis.

RESULTS

Forty-four patients (53.0%) were assigned to the successful jogging group and 39 (47.0%) to the unsuccessful jogging group. QS/BW was independently associated with initiating jogging 3 months after surgery. The cut-off value of QS/BW for successful jogging was 1.45 Nm/kg (area under the curve = 0.94; sensitivity = 88.6%, specificity = 87.2%). All of the patients who initiated jogging with QS/BW of > 1.45 Nm/kg at 3 months returned to sports without recurrence or contralateral injury by 10 months after surgery.

CONCLUSIONS

QS/BW is a significant indicator for safely initiating jogging 3 months after ACL reconstruction. The cut-off value of QS/BW for initiating jogging was 1.45 Nm/kg.

Comparison of two different models of rehabilitation programs following total knee replacement operations

Background

Total knee replacement operation (TKR) is the treatment of choice in severe knee osteoarthritis (OA). Rehabilitation post-TKR is still not well studied. The aim of this study was to compare between the high-intensity (HI) rehabilitation program and the low-intensity (LI) rehabilitation program following TKR.

Results

At 1 month following the TKR operations, significant improvements were found in the first group compared to the second group in all the measured parameters except for the knee range of motion (ROM). At 3 and 12 months follow-up periods, there were statistically significant differences between both groups in all the evaluated parameters except for the numeric pain rating scale and the knee ROM.

Conclusions

Both high-intensity and low-intensity rehabilitation programs are effective; however, HI program had superior functional gain and patient-reported outcomes compared to the LI program. Moreover, HI group has a long-term functional gain.

Adapted protocol of rate of force development and relaxation scaling factor for neuromuscular assessment in patients with knee osteoarthritis

BACKGROUND

The linear relationship between muscle torque and rate of torque rise/relaxation during rapid muscle contractions has been recently introduced as a novel measure of muscle quickness, termed rate of torque development/relaxation scaling factor (RTD-SF/RTR-SF). Because the standard assessment protocol includes potentially painful muscle contractions, the first purpose of this study was to validate an adapted RTD-SF/RTR-SF protocol for knee extensor muscles that utilizes lower submaximal intensities and can be used in knee osteoarthritis patients.

METHODS

A cross-sectional study was performed on a group of healthy controls (n = 24) who underwent the standard RTD-SF/RTR-SF protocol (20-80% of maximum) and the knee osteoarthritis group (n = 24) who underwent the adapted protocol (20-60% of maximum). We calculated the RTD-SF, RTR-SF and the linearity (r²) for both relationships, based on both protocols in controls.

RESULTS

The validity of the adapted protocol was acceptable (intraclass correlation coefficient = 0.77-0.93), with low within-participant variation (coefficient of variability <10%) for both outcome measures. Compared with the control group, the knee osteoarthritis group had similar RTD-SF, but lower linearity of RTD-SF (0.90 vs. 0.82). The RTR-SF (8.0/s vs. 6.7/s) and its linearity (0.87 vs. 0.73) were significantly reduced. Comparing the affected and the unaffected leg in the knee osteoarthritis group, the unaffected leg had greater maximal torque (96.2 vs. 84.1 Nm) and higher linearity for RTD-SF (0.86 vs. 0.80) and RTR-SF (0.82 vs. 0.73).

CONCLUSIONS

We confirmed the validity of the adapted RTD/RTR-SF protocol and its sensitivity to impairments associated with knee osteoarthritis.

Effect of Body Weight-Supported Exercise on Symptoms of Knee Osteoarthritis: A Follow-up Investigation

OBJECTIVE

To examine the long-term effect of participation in a 12-week lower-body positive pressure (LBPP)-supported low-load treadmill exercise regime on knee joint pain, physical function, and thigh muscle strength in patients with knee osteoarthritis (OA).

DESIGN

Prospective, observational, repeated measures.

SETTING

Clinical orthopedic setting.

PATIENTS

Nineteen overweight patients with knee OA.

INTERVENTION

Participants exercised under low-load treadmill walking conditions 2×/week for 12 weeks using an amount of LBPP support that minimized knee pain while walking for a period of 30 minutes at a set speed of 3.1 mph at 0-degree incline.

MAIN OUTCOME MEASURES

Knee pain, function, thigh muscle strength, and body anthropometry were reassessed a minimum of 6 months after completion of the initial exercise regime and compared with results from baseline and postexercise evaluation.

RESULTS

Data suggested that: (1) patients were able to maintain improvements in knee joint pain and symptoms; (2) patients continued to report enhanced joint function and improved quality of life; and (3) patients maintained thigh muscle strength gains. Finally, a majority of patients continued to experience significant reductions in acute knee pain during full weight-bearing treadmill walking.

CONCLUSIONS

Data suggest that improvements in knee pain, joint function, and thigh muscle strength associated with participation in a 12-week LBPP-supported low-load exercise regime were maintained well after cessation of the program. These findings have important implications for the development and refinement of exercise strategies and interventions used in the long-term management of joint symptoms associated with knee OA in overweight patients.

The Importance of Functional Hamstring/Quadriceps Ratios in Knee Osteoarthritis

CONTEXT

Osteoarthritis (OA) is the most common chronic joint condition. Muscle dysfunction plays a critical role in the pathogenesis of knee OA.

OBJECTIVE

It has been suggested that the agonist-antagonist strength relationship for the knee may be better described by a functional hamstring/quadriceps (H/Q) ratio (Hconcentric/Qeccentric: the representative of knee flexion and Qeccentric/Hconcentric: the representative of knee extension). Therefore, in this study, the authors aimed to investigate this ratio and its importance for knee OA.

DESIGN

Cross-sectional study.

SETTING

Research clinic. Patients or Other Participant(s): Twenty healthy women and 20 women with grade 2 or grade 3 primer knee OA between the age of 50 and 80 years were included in this study.

INTERVENTION(S)

Concentric and eccentric peak torque of quadriceps and hamstring muscles were evaluated for all individuals in patient and control groups with a Cybex isokinetic device. Functional H/Q ratio is calculated manually.

MAIN OUTCOME MEASURE(S)

Functional H/Q torque ratios were analyzed between the patients with OA and healthy individuals by using the isokinetic system.

RESULTS

The values of peak torque of hamstring concentric and eccentric and quadriceps concentric for the patient group were significantly lower than the control group (P < .05). No statistically important difference was found for quadriceps eccentric peak torque between 2 groups (P > .05). H/Q ratio for extension in the patient group was significantly higher than the control group (P < .05), whereas the H/Q ratio for flexion in the patient group was significantly lower than the control group (P < .05).

CONCLUSION

This study showed the weakness of both quadriceps and hamstring muscles in patients with knee OA. The combination of functional H/Q ratio with hamstring and quadriceps muscles concentric and eccentric strength values can help to analyze the knee functions and develop preventive-therapeutic approaches for knee OA.

Influence of Antagonistic Hamstring Coactivation on Measurement of Quadriceps Strength in Older Adults

BACKGROUND

There is limited understanding of how antagonist muscle coactivation relates to measurement of strength in both individuals with and without knee osteoarthritis (KOA).

OBJECTIVE

This study sought to determine whether hamstring coactivation during a maximal quadriceps activation task attenuates net quadriceps strength.

DESIGN

Cross-sectional cohort analysis was conducted using data from the 60-month visit of the Multicenter Osteoarthritis Study (MOST).

SETTING

Laboratory.

PARTICIPANTS

A sample of 2328 community-dwelling MOST participants between the ages of 55 and 84 years, with or at elevated risk for KOA, completed the 60-month MOST follow-up visit. Of these, 1666 met inclusion criteria for the current study.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

Quadriceps strength; percentage of combined hamstring coactivation (HC), medial HC, and lateral HC. Quadriceps and hamstring strength were assessed using an isokinetic dynamometer. Surface electromyography was used to assess muscle activation patterns. General linear models, adjusted for age, BMI, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Kellgren-Lawrence (KL) grade and study site, modeled the relationship between antagonist hamstring coactivation and quadriceps strength.

RESULTS

Men had significantly greater quadriceps strength (P < .001), history of knee injury (P < .001) and surgery (P = .002), and greater presence of varus malalignment (P < .001). Women had greater pain (P < .001) and proportion of KL grade ≥2 (P = .017). Gender-specific analyses revealed combined HC (P = .013) and lateral HC inversely associated with quadriceps strength in women (P = .023) but not in men (combined HC P = .320, lateral HC P = .755). A nonlinear association was detected between quadriceps strength and medial HC. Assessment of quartiles of medial HC revealed the third quartile had reduced quadriceps strength when compared to the lowest quartile of coactivation in both men and women.

CONCLUSIONS

Hamstring coactivation attenuates measured quadriceps strength in women with or at elevated risk for KOA.

LEVEL OF EVIDENCE

II.

Functional movement compensations persist in individuals with hip osteoarthritis performing the five times sit-to-stand test 1 year after total hip arthroplasty

Background

Methods to quantify and evaluate function are important for development of specific rehabilitation interventions. This study aimed to evaluate functional movement compensation in individuals with hip osteoarthritis performing the five times sit-to-stand test and change following total hip arthroplasty. To this end, trajectories of the body’s center of mass in the medial-lateral and anterior-posterior dimensions were quantified prior to and 1 year after total hip arthroplasty and compared to a healthy control group.

Methods

Twenty-eight individuals with hip osteoarthritis and 21 matched healthy controls were enrolled in this prospective study. Within 1 month prior to and 1 year after total hip arthroplasty, performance on the five times sit-to-stand test was evaluated using three-dimensional motion analysis and perceived pain using a visual analog scale. The center of mass trajectories for the medial-lateral and the anterior-posterior dimensions were identified, and the area under the curve was calculated, respectively. Repeated measures ANOVA were used to evaluate differences in the area under the curve, between pre- and postoperative performance, and between participants with hip osteoarthritis and controls.

Results

Preoperatively, individuals with hip osteoarthritis displayed a larger contralateral shift (p < 0.001) and forward displacement of the center of mass (p = 0.022) compared to controls. After surgery, deviations in both dimensions were reduced (medial-lateral p = 0.013; anterior-posterior p = 0.009). However, as compared to controls, the contralateral shift of the center of mass remained larger (p = 0.010), indicative of persistent asymmetric limb loading. Perceived pain was significantly reduced postoperatively (p < 0.001).

Conclusions

By quantifying the center of mass trajectory during five times sit-to-stand test performance, functional movement compensations could be detected and evaluated over time. Prior to total hip arthroplasty, individuals with hip osteoarthritis presented with an increased contralateral shift and forward displacement of the center of mass, representing a strategy to reduce pain by unloading the affected hip and reducing required hip and knee extension moments. After surgery, individuals with total hip arthroplasty displayed a persistent increased contralateral shift as compared to controls. This finding has implications for rehabilitation, where more focus must be directed towards normalizing loading of the limbs.

Association between severity of depressive symptoms and chronic knee pain in Korean adults aged over 50 years: a cross-sectional study using nationally representative data

OBJECTIVES

To identify the association between the presence and severity of depressive symptoms and those of chronic knee pain.

DESIGN

A retrospective cross-sectional study.

PARTICIPANTS

We used data from the sixth Korea National Health and Nutrition Examination Survey (KNHANES VI-2) performed in 2014. Overall, 7550 patients were included in the KNHANES VI-2.

OUTCOME MEASURES

Participants were asked whether they had chronic knee pain, and each answer was either 'yes' or 'no'. Patient Health Questionnaire-9 (PHQ-9) was used as a screening tool for depressive symptoms, and PHQ-9 scores of 10 or higher was classified as the depressed group. In total, 527 patients reported that they had pain in their knee, of whom 91 also had depressive symptoms.

RESULTS

The prevalence of chronic knee pain in the Korean population aged over 50 years was 19.8%. Multiple logistic regression was conducted after adjustment for sex, age, smoking, alcohol drinking, education level, household income, physical activity, sleep duration and comorbidity. The analysis revealed a significant association between depressive symptoms and chronic knee pain (adjusted OR=2.333, p<0.001). In contrast, the severity of depressive symptoms was linearly correlated with the intensity of chronic knee pain (p for trend <0.001). In participants with no chronic knee pain (Numerical Rating Scale; NRS=0) or mild chronic knee pain (NRS=1-4), the prevalence of moderate and severe depressive symptoms was 3.4% and 0.6%, respectively. However, in those with severe chronic knee pain (NRS=8-10), there was a higher prevalence of moderate and severe depressive symptoms (10.1% and 5.8%, respectively) (p<0.001).

CONCLUSIONS

A strong association was observed between the presence and severity of depressive symptoms and the presence of chronic knee pain. The association became stronger with higher levels of depressive symptoms, indicating a positive correlation between depressive symptoms severity and chronic knee pain.

Abnormal Joint Loading During Gait in Persons With Hip Osteoarthritis Is Associated With Symptoms and Cartilage Lesions

BACKGROUND

Hip joint loading in persons with hip osteoarthritis (OA) is not well studied, and its associations with symptoms and lesions are unknown.

OBJECTIVES

To determine whether hip joint loading differs between people with and without radiographic hip OA, and to identify its associations with patients' symptoms and cartilage morphology.

METHODS

Forty-eight patients (28 male; mean ± SD age, 56.0 ± 12.2 years) with hip OA and 95 controls (40 male; age, 43.2 ± 13.6 years) participated in this cross-sectional analysis. Pelvic radiographs, questionnaires, magnetic resonance imaging (MRI), and gait analysis were conducted. The Hip disability and Osteoarthritis Outcome Score (HOOS) was used to assess symptoms. Cartilage morphology was graded on MRI scans using the Scoring Hip Osteoarthritis with Magnetic Resonance Imaging (SHOMRI) system. Biomechanical variables included peak external hip joint moment (Newton meters per kilogram) and moment impulses (Newton meters times milliseconds per kilogram) in all planes. Generalized estimating equations were used to compare the biomechanical characteristics between groups. In the patients with OA, associations of moment impulses with HOOS and SHOMRI scores were assessed with partial correlations.

RESULTS

The OA group exhibited higher peak external hip flexion and adduction moments (P<.001) and higher hip flexion, adduction, and external rotation moment impulses (P = .001-.039). Increased hip flexion moment impulses were correlated with worse HOOS subscale scores (r = -0.361 to -0.424, P<.05) and worse femoral SHOMRI grades (ρ = 0.256-0.315, P<.05). Increased hip external rotation moment impulses were correlated with worse femoral SHOMRI grades (ρ = 0.283-0.372, P<.05).

CONCLUSION

Persons with hip OA exhibited abnormally high hip joint loads during walking, and high loads were associated with worse self-reported symptoms and cartilage morphology. J Orthop Sports Phys Ther 2019;49(12):917-924. Epub 14 Oct 2019. doi:10.2519/jospt.2019.8945.

Dao Yin (a.k.a. Qigong): Origin, Development, Potential Mechanisms, and Clinical Applications

Dao Yin is a form of exercise combining physical movements, mental focus, and breathing originated in ancient China. In this review, we introduce the history in the development and the scope of Dao Yin, the relationship between Dao Yin with Taoist culture and Qigong, and the potential mechanisms of how Dao Yin promotes health and alleviate illnesses. Empirical research studies using Dao Yin for treatment of lumbar spondylosis, peripheral musculoskeletal diseases, cervical spondylosis, heart diseases, central nervous system disorders, immunological dysfunction, and psychological disorders are detailed.

Biomechanical Changes Following Knee Arthroplasty During Sit-To-Stand Transfers: Systematic Review

BACKGROUND

Knee arthroplasty (KA) is a common and effective surgical procedure that allows patients with knee osteoarthritis to restore functional ability and relieve pain. Sit-to-stand is a common demanding task during activities of daily living and is performed more than 50 times per day. The purpose of this systematic review is to obtain a comprehensive understanding of biomechanical changes during sit-to-stand transfers following KA.

METHODS

Relevant articles were selected through MEDLINE (PubMed), Scopus, Embrace, and Web of Science. Articles were included if they met the following inclusion criteria: (1) underwent KA without restriction on the arthroplasty design, (2) involve kinematic, kinetic, or muscle activity variables as the primary outcome measure, (3) evaluated sit-to-stand, and (4) were written in English.

RESULTS

A total of 13 articles were included in the current systematic review. The KA group exhibited altered movement patterns as compared to healthy controls. Considering the time course of recovery, improvement in knee joint kinematics was found up to 2 years but kinetic changes indicate intensified contralateral limb loading. For comparisons for limbs, limb differences were apparent, but those differences were resolved by 1 year.

CONCLUSION

Despite the inevitable changes in kinematics, kinetics, and muscle activity in sit-to-stand since KA, it appears to be important to restore quadriceps strength for the operative limb in order to minimize risk for subsequent joint problems.

Establishing outcome measures in early knee osteoarthritis

The classification and monitoring of individuals with early knee osteoarthritis (OA) are important considerations for the design and evaluation of therapeutic interventions and require the identification of appropriate outcome measures. Potential outcome domains to assess for early OA include patient-reported outcomes (such as pain, function and quality of life), features of clinical examination (such as joint line tenderness and crepitus), objective measures of physical function, levels of physical activity, features of imaging modalities (such as of magnetic resonance imaging) and biochemical markers in body fluid. Patient characteristics such as adiposity and biomechanics of the knee could also have relevance to the assessment of early OA. Importantly, research is needed to enable the selection of outcome measures that are feasible, reliable and validated in individuals at risk of knee OA or with early knee OA. In this Perspectives article, potential outcome measures for early symptomatic knee OA are discussed, including those measures that could be of use in clinical practice and/or the research setting.

Evaluation of a health trainer–led service for people with knee, hip and back pain

Aims:

Chronic knee, hip and back pain is extremely prevalent. Management guidelines emphasise maintaining physical activity and healthy weight to reduce pain and improve physical and mental wellbeing. Unfortunately, few people receive support to make lifestyle changes. We evaluated whether a health trainer—led ‘joint pain advice’ (JPA) service delivering person-centred lifestyle coaching was feasible, acceptable and effective for people with knee, hip and back pain.

Methods:

Feasibility of delivering a JPA service was assessed by documenting whether the health trainers could deliver JPA and its uptake. Nine health trainers delivered JPA. Participants were offered up to four appointments. At each appointment, health trainers gave people information about their condition, co-developed care plans, suggested self-management strategies and used behavioural change techniques (motivational interviewing, goal-setting and action planning) to increase physical activity and reduce body weight. Pain, function, physical activity and body mass index (BMI) were collected at baseline, 3 weeks, 6 weeks and 6 months. Focus groups captured people’s opinions of the service’s effectiveness, acceptability and usefulness.

Results:

Of the 105 people who enquired about JPA, 85 (81%) used the service, after which their physical activity and function improved, and pain, use of analgesia and BMI decreased. They felt more knowledgeable and better motivated to adopt and maintain healthier behaviours. They attributed these improvements to the JPA service, because of its better consultations and collaborative holistic approach. Only a minority attended all four appointments because they felt they received sufficient advice from the initial appointments. The health trainers gained knowledge and skills to support clients with musculoskeletal conditions.

Conclusions:

Using a holistic, patient-centred approach, health trainers can deliver lifestyle advice to people with chronic knee, hip or back pain safely, effectively and efficiently. The service was popular with recipients and health trainers, and helped people adopt healthier lifestyles that lead to reduced pain and other clinical improvements.

Patients With Unilateral Femoroacetabular Impingement Syndrome Have Asymmetrical Hip Muscle Cross-Sectional Area and Compensatory Muscle Changes Associated With Preoperative Pain Level

PURPOSE

To compare the symptomatic hip muscle cross-sectional area (CSA) in patients with unilateral femoroacetabular impingement syndrome (FAIS) with the asymptomatic-side hip muscle CSA and to determine whether correlations exist between the hip muscle CSA and preoperative pain level, preoperative symptom duration, and postoperative function.

METHODS

We performed a retrospective review of magnetic resonance imaging data of patients who underwent hip arthroscopy from January 2012 through June 2015 for the treatment of unilateral FAIS and who had a minimum of 2 years' follow-up after hip arthroscopy for FAIS. A picture archiving and communication system workstation with an embedded region-of-interest tool was used to measure the muscle CSA of both the symptomatic and asymptomatic sides in FAIS patients. One-way repeated-measures analyses of variance were used to determine differences between symptomatic and asymptomatic hip muscle CSAs. Spearman rank correlations were used to determine relations between the symptomatic-side hip muscle CSA and preoperative pain level, preoperative symptom duration, and multiple validated patient-reported outcomes to quantify the level of function.

RESULTS

A total of 50 patients met the inclusion criteria and were analyzed. The mean age of the patients was 34.22 ± 14.12 years, and 64% were women. Specific muscles of the symptomatic hip displaying significantly decreased CSAs compared with the asymptomatic hip included the gluteus maximus (P = .007), gluteus minimus (P = .022), and rectus femoris (P = .028). The tensor fascia lata (ρ = 0.358; P = .011), pectineus (ρ = 0.369, P = .008), adductor longus (ρ = 0.286, P = .044), and obturator externus (ρ = 0.339, P = .016) showed a moderate positive correlation with preoperative pain level on a visual analog scale in unilateral FAIS patients. No associations were found between the symptomatic-side hip muscle CSA in patients with unilateral FAIS and symptom duration or patient-reported function.

CONCLUSIONS

Patients with unilateral FAIS have a significantly decreased muscle CSA in the symptomatic hip compared with the asymptomatic hip. The symptomatic-side hip muscle CSA was correlated with the preoperative pain level on a visual analog scale. The association between the muscle CSA and preoperative pain level may represent a compensatory change in muscle function around the hip joint in patients with unilateral FAIS.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Ligamento-Muscular Reflex Patterns Following Stimulation of a Thumb Carpometacarpal Ligament: An Electromyographic Study

PURPOSE

The dorsoradial ligament (DRL) is essential for stability of the first carpometacarpal joint (CMC1) and is innervated with nerve endings and mechanoreceptors known to contribute to joint proprioception. The influence of these nerve endings on the neuromuscular stability of CMC1 is not yet known. This study investigated whether a ligamento-muscular reflex pathway is present between the DRL and CMC1 muscles.

METHODS

Ten healthy subjects (5 women and 5 men, mean age 28 years; range, 24-37 years) were included. Four primary CMC1 stabilizing muscles were investigated: the extensor pollicis longus, abductor pollicis longus (APL), abductor pollicis brevis, and first dorsal interosseous. Needle electrodes were inserted into each muscle and a fine-wire electrode was inserted into the DRL. The DRL was stimulated at 200 MHz while EMG activities in the muscles were recorded during isometric tip, key, and palmar pinch. Average EMG values were analyzed to compare prestimulus (t₁) with post-stimulus (t₂) activity.

RESULTS

Poststimulus changes were observed in all 4 muscles and 3 positions tested. During tip pinch we observed mass inhibition with a decrease in all muscle amplitudes. In key pinch we observed a rapid co-contraction response. Rapid inhibitory response of antagonistic musculature was observed during palmar pinch. The APL was the only muscle to react within 20 ms after stimulation.

CONCLUSIONS

We identified CMC1 ligamento-muscular reflexes. The mass inhibition of activity observed during tip pinch indicated a protective ligamento-muscular relation that affects all 4 muscles. The co-contractions observed promote joint stability. The fast response in the APL, coupled with its neuroanatomical proximity to the DRL, indicate a particular role in CMC1 proprioception.

CLINICAL RELEVANCE

Proper ligamentous support and retained innervation is likely important for adequate joint function; their innate functions ought to be considered when planning surgical or orthotic treatments.

Short-term effects of neuromuscular electrical stimulation and ultrasound therapies on muscle architecture and functional capacity in knee osteoarthritis: a randomized study

Objective:

To determine the effects of ultrasound therapy and neuromuscular electrical stimulation (NMES) application on the muscle architecture and functional capacity in patients with knee osteoarthritis.

Design:

A randomized study.

Subjects:

A total of 60 patients with knee osteoarthritis.

Interventions:

Participants were randomized into one of the following two intervention groups, five days a week, for three weeks: the combination of NMES application, hot pack, and exercise therapy was applied to the NMES group. The combination of therapeutic ultrasound, hot pack and exercise therapy was applied to the ultrasound therapy group.

Main measures:

Subjects were evaluated for pain and functional capacity with the use of the visual analog pain scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 15 meter walking test. The muscle architecture (muscle thickness, pennation angle and fascicle length) was assessed from vastus lateralis and quadriceps femoris muscles bilaterally by ultrasonography.

Results:

Two groups presented significant improvements in all outcome measures before and after treatment ( P < 0.01). There were significant improvements in VAS rest pain ( P < 0.05), VAS activity pain ( P < 0.05), WOMAC pain ( P < 0.05), WOMAC stiffness score ( P < 0.05), and WOMAC physical function ( P < 0.05) for the ultrasound therapy group in comparison to the NMES group. NMES group exhibited more increases in the muscle thickness and fascicle length values when compared to ultrasound therapy group ( P < 0.05).

Conclusion:

Ultrasound therapy appears to be an effective treatment in reducing pain and improving functional capacity. NMES application has more effects on the muscle architecture.

Strengthening the quadriceps femoris muscle versus other knee training programs for the treatment of knee osteoarthritis

People with knee osteoarthritis have atrophy of the muscles surrounding the knee joint. Therefore, exercise programs primarily have been focused on the strengthening of quadriceps femoris muscle (QFM). Primary aim of this systematic review was to determine which exercise increases strength of the QFM and describe the details of the training programs. Secondary aim was to determine effectiveness of strengthening of the QFM alone on pain and dysfunction in patient with knee osteoarthritis. PubMed, PEDro, and Cochrane were searched. PEDro for methodological quality of randomized controlled trials and Cochrane Collaborations' tool for risk of bias were used. A total of 1128 articles were identified from the database searches. Ten studies which were moderate-to-high level of evidence were included. In the comparison of different strengthening exercises of the QFM, significant difference was not found between training groups. However, strengthening of the QFM exercise training was superior to proprioceptive training. Additional hot packs plus shortwave diathermy or ultrasound or transcutaneous electrical nerve stimulation had superiority to isokinetic strengthening of the QFM alone. Only additional Russian electrical stimulation showed the significant difference compared with strengthening of the QFM exercise. Most of the included studies showed that strengthening of the QFM exercises has an effect on pain reduction and improvement of function. This review indicated that the strengthening of QFM training compared with other knee exercises provided muscle strengthening, pain reduction, and improved function while combination with other electrotherapy modalities or combination with Russian electrical stimulation had superiority to alone strengthening QFM training.