Intra-articular knee joint effusion induces quadriceps avoidance gait patterns

The past and future of peri-operative interventions to reduce arthrogenic quadriceps muscle inhibition after total knee arthroplasty: A narrative review

Total knee arthroplasty (TKA) improves patient-reported function by alleviating joint pain, however the surgical trauma exacerbates already impaired muscle function, which leads to further muscle weakness and disability after surgery. This early postoperative strength loss indicates a massive neural inhibition and is primarily driven by a deficit in quadriceps muscle activation, a process known as arthrogenic muscle inhibition (AMI). To enhance acute recovery of quadriceps muscle function and long-term rehabilitation of individuals after TKA, AMI must be significantly reduced in the early post-operative period. The aim of this narrative review is to review and discuss previous efforts to mitigate AMI after TKA and to suggest new approaches and interventions for future efficacy evaluation. Several strategies have been explored to reduce the degree of post-operative quadriceps AMI and improve strength recovery after TKA by targeting post-operative swelling and inflammation or changing neural discharge. A challenge of this work is the ability to directly measure AMI and relevant contributing factors. For this review we focused on interventions that aimed to reduce post-operative swelling or improve knee extension strength or quadriceps muscle activation measured by twitch interpolation. For individuals undergoing TKA, the use of anti-inflammatory medications, tranexamic acid, cryotherapy, intra-articular drains, torniquets, and minimally invasive surgical techniques for TKA have limited benefit in attenuating quadriceps AMI early after surgery. However, interventions such as inelastic compression garments, voluntary muscle contractions, and neuro-muscular electrical stimulation show promise in mitigating or circumventing AMI and should continue to be refined and explored.

Quadriceps Weakness is Associated with Neuroplastic Changes Within Specific Corticospinal Pathways and Brain Areas After Anterior Cruciate Ligament Reconstruction: Theoretical Utility of Motor Imagery-Based Brain-Computer Interface Technology for Rehabilitation

Persistent quadriceps weakness is a problematic sequela of anterior cruciate ligament reconstruction (ACLR). The purposes of this review are to summarize neuroplastic changes after ACL reconstruction; provide an overview of a promising interventions, motor imagery (MI), and its utility in muscle activation; and propose a framework using a brain-computer interface (BCI) to augment quadriceps activation. A literature review of neuroplastic changes, MI training, and BCI-MI technology in postoperative neuromuscular rehabilitation was conducted in PubMed, Embase, and Scopus. Combinations of the following search terms were used to identify articles: "quadriceps muscle," "neurofeedback," "biofeedback," "muscle activation," "motor learning," "anterior cruciate ligament," and "cortical plasticity." We found that ACLR disrupts sensory input from the quadriceps, which results in reduced sensitivity to electrochemical neuronal signals, an increase in central inhibition of neurons regulating quadriceps control and dampening of reflexive motor activity. MI training consists of visualizing an action, without physically engaging in muscle activity. Imagined motor output during MI training increases the sensitivity and conductivity of corticospinal tracts emerging from the primary motor cortex, which helps "exercise" the connections between the brain and target muscle tissues. Motor rehabilitation studies using BCI-MI technology have demonstrated increased excitability of the motor cortex, corticospinal tract, spinal motor neurons, and disinhibition of inhibitory interneurons. This technology has been validated and successfully applied in the recovery of atrophied neuromuscular pathways in stroke patients but has yet to be investigated in peripheral neuromuscular insults, such as ACL injury and reconstruction. Well-designed clinical studies may assess the impact of BCI on clinical outcomes and recovery time. Quadriceps weakness is associated with neuroplastic changes within specific corticospinal pathways and brain areas. BCI-MI shows strong potential for facilitating recovery of atrophied neuromuscular pathways after ACLR and may offer an innovative, multidisciplinary approach to orthopaedic care.

Level of Evidence

V, expert opinion.

Changes and Associations Between Gait Biomechanics and Knee Inflammation After Aspiration and Glucocorticoid Injection for Knee Osteoarthritis

OBJECTIVE

Although knee inflammation is thought to adversely affect joint function in patients with knee osteoarthritis (OA), the effects of reducing knee inflammation on gait biomechanics and strength are unknown. Our objectives were to compare ultrasound (US) measures of knee inflammation, gait biomechanics, knee extension and flexion strength, and pain before and after knee aspiration and glucocorticoid injection, and to explore associations among changes.

METHODS

Forty-nine patients (69 knees) with symptomatic knee OA and synovitis were tested before and 3-4 weeks after US-guided knee aspiration and glucocorticoid injection. At each visit, participants completed US assessments for inflammatory features of knee OA, 3D gait analysis, isokinetic knee extension and flexion strength tests, and Knee Osteoarthritis Outcome Score (KOOS) pain subscales. Linear and polynomial mixed-effects regression models were used to investigate changes and their associations.

RESULTS

Changes were observed for the synovitis score (unstandardized β [post-injection minus pre-injection] -0.55/9 [95% confidence interval (95% CI) -0.97, -0.12]), effusion depth (-1.05 mm [95% CI -1.07, -0.39]), KOOS pain (unstandardized β 5.91/100 [95% CI 1.86, 9.97]), peak external knee flexion and extension moments (KFM; 3.33 Nm [95% CI 0.45, 6.22]), KEM (-2.99 Nm [95% CI -5.93, -0.05]), and knee extension strength (4.70 Nm [95% CI 0.39, 9.00]) and flexion strength (3.91 Nm [95% CI 1.50, 6.81]). The external KFM increased during 13-38% and 76-89% of stance post-injection. When controlled for time, greater synovitis was associated with lower knee extension strength, while lower pain was associated with increased knee extension and flexion strength.

CONCLUSION

In patients with knee OA and synovitis, reduced inflammation and pain after aspiration and glucocorticoid injection are associated with changes in knee gait biomechanics and strength.

Spinal Reflex Excitability of Lower Leg Muscles Following Acute Lateral Ankle Sprain: Bilateral Inhibition of Soleus Spinal Reflex Excitability

Neural changes in the ankle stabilizing muscles following ankle sprains are thought to be one contributing factor to persistent ankle dysfunction. However, empirical evidence is limited. Therefore, we aimed to examine spinal reflex excitability of lower leg muscles following acute ankle sprains (AAS). We performed a case-control study with 2 groups consisting of 30 young adults with AAS and 30 aged-matched uninjured controls. Hoffmann reflex (H-reflex) testing was performed to estimate spinal reflex excitability of lower leg muscles: soleus, fibularis longus (FL), tibialis anterior (TA). Maximal H-reflex (H_max) and motor responses (M_max) were determined by delivering a series of electrical stimuli at the sciatic nerve. H_max/M_max ratios were calculated to represent normalized spinal reflex excitability. Separate group-by-limb analyses of variance (ANOVA) with repeated measures found there were no significant interactions for any of the muscles (SL: F_1,56 = 0.95, p = 0.33, FL: F_1,51 = 0.65, p = 0.42, TA: F_1,51 = 1.87, p = 0.18), but there was a significant main effect of group in the soleus (F_1,56 = 6.56, p = 0.013), indicating the H_max/M_max ratio of soleus in the AAS group was significantly lower bilaterally (AAS = 0.56 ± 0.19, control = 0.68 ± 0.17, p = 0.013), with no significant group differences in the other muscles (FL: F_1,51 = 0.26, p = 0.61, TA: F_1,51 = 0.93, p = 0.34). The bilateral inhibition of the soleus spinal reflex excitability following AAS may be significant in that it may explain bilateral sensorimotor deficits (postural control deficits) following unilateral injury, and provide insights into additional therapies aimed at the neural change.

Feasibility and initial efficacy of a multimodal swelling intervention after total knee arthroplasty: A prospective pilot study with historical controls

BACKGROUND

Swelling after total knee arthroplasty (TKA) is often profound and persistent, increasing risks of DVT, infection, and wound dehiscence, and impairing rehabilitation. We investigated the feasibility and initial efficacy of a multimodal swelling control intervention (MSI), comprised of an inelastic adjustable compression garment (CG), manual lymph drainage (MLD) massage, and home exercise program (HEP) after total knee arthroplasty (TKA) compared to a control group.

METHODS

Sixteen individuals (mean age 64.7 ± 7.1y) performed MSI for three weeks after TKA, through day 21 (D21). Outcome measures included patient satisfaction, safety, patient adherence, and swelling measured by Single Frequency Bioimpedance Assessment (SF-BIA). All outcomes were measured preoperatively and at postoperative D4, D7, D14, D21 and, three weeks after discontinuing MSI, on D42. Efficacy of MSI was calculated with Hedge's g effect size estimates using the SF-BIA ratios for MSI versus CONTROL (N = 56; mean age 64.3 ± 9.3y) at key post operative time points.

RESULTS

Patient satisfaction was 93% with no adverse events. Adherence to CG, MLD, and HEP were 85%, 99%, and 97% respectively. Peak swelling reduction with MSI was at D21 (Hedges' g = 1.60 at D21 (95% CI 0.99, 2.21)). Minimal change in swelling was observed three weeks after cessation of MSI on D42.

CONCLUSIONS

The self-administered MSI program is feasible and demonstrated strong initial efficacy to control swelling after TKA. Minimal rebound swelling was observed once MSI was withdrawn at D21. Future studies should examine the efficacy of inelastic adjustable compression in a randomized controlled trial.

Arthrogenic Muscle Inhibition Following Anterior Cruciate Ligament Injury

Arthrogenic muscle inhibition (AMI) is a common impairment in individuals who sustain an anterior cruciate ligament (ACL) injury. The AMI causes decreased muscle activation, which impairs muscle strength, leading to aberrant movement biomechanics. The AMI is often resistant to traditional rehabilitation techniques, which leads to persistent neuromuscular deficits following ACL reconstruction. To better treat AMI following ACL injury and ACL reconstruction, it is important to understand the specific neural pathways involved in AMI pathogenesis, as well as the changes in muscle function that may impact movement biomechanics and long-term structural alterations to joint tissue. Overall, AMI is a critical factor that limits optimal rehabilitation outcomes following ACL injury and ACL reconstruction. This review discusses the current understanding of the: (1) neural pathways involved in the AMI pathogenesis following ACL injury; (2) consequence of AMI on muscle function, joint biomechanics, and patient function; and (3) development of posttraumatic osteoarthritis. Finally, the authors review the evidence for interventions specifically used to target AMI following ACL injury.

Synovial tissue perivascular edema is associated with altered gait patterns in patients with knee osteoarthritis

OBJECTIVE

To explore mechanisms of mechanoinflammation, we investigated the association between the presence of knee synovial perivascular edema and gait biomechanics that serve as surrogate measures of knee load in patients with knee osteoarthritis (OA).

DESIGN

Patients with symptomatic, radiographic knee OA and neutral to varus alignment undergoing total knee arthroplasty or high tibial osteotomy participated in this cross-sectional analysis. All participants underwent 3D gait analysis prior to surgery. Synovial biopsies were obtained during surgery for histopathological assessment. The association between the presence of synovial perivascular edema (predictor) and the external knee moment (outcome) in each orthogonal plane was analyzed using multivariate linear regression and polynomial mixed effects regression models, while adjusting for age, sex, BMI, and gait speed.

RESULTS

Ninety-two patients with complete gait and histopathological data were included. When fitted over 100% of stance, regression models indicated substantial differences between patients with and without synovial perivascular edema for knee moments in frontal, sagittal and transverse planes. The knee adduction moment was higher in patients with edema from 16 to 74% of stance, with the largest difference at 33% of stance (β = 6.87 Nm [95%CI 3.02, 10.72]); whereas the knee flexion-extension moment differed from 15 to 92% of stance, with the largest difference in extension at 60% of stance (β = -10.80 Nm [95%CI -16.20, -5.40]).

CONCLUSIONS

In patients with knee OA, the presence of synovial perivascular edema identified by histopathology is associated with aberrant patterns of knee loading throughout stance, supporting the link between biomechanics and synovial inflammation.

Preoperative muscle thickness influences muscle activation after arthroscopic knee surgery

PURPOSE

The aim of this study was to compare the correlation between preoperative quadriceps femoris muscle thickness and postoperative neuromuscular activation and quadriceps femoris strength in patients with and without patellofemoral pain after arthroscopic partial meniscectomy.

METHODS

A series of 120 patients were prospectively analysed in a longitudinal cohort study of patients scheduled for arthroscopic partial meniscectomy. The patellofemoral pain group included patients who developed anterior knee pain after surgery while the control group included those who had not done so. Patients with preoperative patellofemoral pain, previous knee surgeries as well as those on whom additional surgical procedures had been performed were excluded. Of the 120 initially included in the study, 90 patients were analysed after the exclusions.

RESULTS

There is a direct correlation between preoperative quadriceps femoris muscle thickness and the neuromuscular activity values and the strength of the muscle at 6 weeks after surgery. These results were seen exclusively in the group of patients who do not develop patellofemoral pain (0.543, p = 0.008). The group of patients who developed anterior knee pain in the postoperative period did not show this correlation (n.s.).

CONCLUSION

In patients without patellofemoral pain after meniscectomy, the greater the preoperative thickness of the quadriceps femoris, the more postoperative neuromuscular activation and strength they had. This correlation did not occur in those patients who develop patellofemoral pain after meniscal surgery.

LEVEL OF EVIDENCE

II.

Anterior knee pain independently alters landing and jumping biomechanics

Background Biomechanical effects of anterior knee pain are difficult to distinguish from effects of other factors also related to knee injury (e.g., joint effusion). The purpose of this study was to evaluate independent effects of anterior knee pain on landing and jumping biomechanics. Methods Thirteen healthy participants performed a land and jump movement task, under three experimental conditions (pre-pain, pain, and post-pain), during one data collection session. One 1-ml injection of hypertonic saline into the infrapatellar fat pad was used to induce experimental anterior knee pain during the pain condition. Participant-perceived anterior knee pain was measured every 2 min throughout data collection. Landing and jumping biomechanics were measured and compared between the experimental conditions using a functional statistical approach. Findings The aforementioned injection increased mean participant-perceived anterior knee pain, from zero during the pre-pain condition to 2.6 ± 0.71 cm during the pain condition. Vertical ground reaction force, knee flexion angle, and internal knee extension moment decreased by approximately 0.100 body weights, 3°, and 0.010 Nm/body weight × body height, respectively, between the pre-pain and pain conditions. Conversely, hip flexion angle and internal hip extension moment increased by approximately 3° and 0.006 Nm/body weight × body height, respectively, between the pre-pain and pain conditions. Several biomechanical changes persisted after anterior knee pain abatement (the post-pain condition). Interpretation Anterior knee pain alters landing and jumping biomechanics, independent of other injury-related factors. These altered biomechanics likely change knee joint loading patterns and might increase risk for chronic knee joint injury and/or pathology.

Mechanisms of Arthrogenic Muscle Inhibition

CONTEXT

Arthrogenic muscle inhibition (AMI) continues to be a limiting factor in joint rehabilitation as the inability to volitionally activate muscle significantly dampens recovery. New evidence acquired at higher brain centers and in clinical populations continues to reshape our perspective of what AMI is and how to treat it. This review aims to stimulate discussion about the far-reaching effects of AMI by exploring the interconnected pathways by which it evolves.

OBJECTIVES

To discuss how reflexive inhibition can lead to adaptations in brain activity, to illustrate how changes in descending motor pathways limit our ability to contract muscle following injury, and to summarize the emerging literature on the wide-reaching effects of AMI on other interconnected systems.

DATA SOURCES

The databases PubMed, SPORTDiscus, and Web of Science were searched for articles pertaining to AMI. Reference lists from appropriate articles were cross-referenced.

CONCLUSION

AMI is a sequential and cumulative neurological process that leads to complex clinical impairments. Originating with altered afferent information arising from an injured joint, patients experience changes in afferent information, reflexive muscle inhibition, deficiencies in somatosensation, neuroplastic compensations in higher brain centers, and ultimately decreased motor output to the muscle surrounding the joint. Other aspects of clinical function, like muscle structure and psychological responses to injury, are also impaired and influenced by AMI. Removing, or reducing, AMI should continue to be a focus of rehabilitation programs to assist in the optimization of health after joint injury.

Joint Corticosteroid Injection Associated With Higher Physical Therapy Compliance in Knee Osteoarthritis

Background Knee corticosteroid injection (KCSI) and physical therapy (PT) are two efficacious treatments for knee osteoarthritis (KOA). However, poor adherence to PT in resource-limited communities might limit its effectiveness. KCSI prior to PT might improve adherence in this population. Methodology This was a retrospective cohort analysis of patients referred to PT for KOA from January 01, 2018 to December 31, 2019 from an adult primary care resident clinic in Hartford, Connecticut, USA. Patients were divided into two groups, namely, those who had a KCSI around the time of the referral versus those who did not. PT adherence was evaluated in both groups. Results A total of 143 patients referred to PT were selected, and 11 patients were excluded. In total, 38/132 patients had a KCSI within a four-month window of the PT referral. Patients were mostly Hispanic (no injection 79.8% vs. injection 78.9%) females (80.9% vs. 71.1%), the average age was in the 60s, and over 90% were insured by either Medicaid or Medicare. In the injection group, 18/38 patients completed at least one PT visit (47.4%) versus 21/94 patients (22.3%) in the noninjection group. The odds ratio of undergoing PT was 1.38 (95% confidence interval [CI] = 1.14-1.69; p = 0.002), and the rate ratio of PT visits was 2.50 (95% CI = 1.82-3.42; p = 1.36 × 10-8), both adjusted for age, sex, and severity. Among those who attended at least one session, the mean number of PT visits was 5.4 in both injection and noninjection groups (median 5 versus 4).  Conclusions In a predominantly Hispanic patient population, those who underwent KCSI were more likely to undergo PT and, as a group, attend more sessions.

Synovial fluid concentrations of matrix Metalloproteinase-3 and Interluekin-6 following anterior cruciate ligament injury associate with gait biomechanics 6 months following reconstruction

OBJECTIVE

To compare gait biomechanics 6 months following anterior cruciate ligament (ACL) reconstruction (ACLR) between patients with the highest and lowest concentrations of synovial fluid (SF) interleukin-6 (IL-6) and matrix metalloproteinase-3 (MMP-3), as well as compared to uninjured controls.

DESIGN

SF concentrations of IL-6 and MMP-3 were collected 7 ± 4 days post injury in 38 ACL injured patients (55% female, 21±4yrs, 25.3 ± 5.2BMI). ACL injured individuals were stratified into the lowest and highest quartiles based on IL-6 (IL-6_Lowest and IL-6_Highest) and MMP-3 (MMP-3_Lowest and MMP-3_Highest) concentrations. Gait biomechanics were collected on the injured limb 6 months post-ACLR and in 38 uninjured controls (50% female, 21±3yrs, 23.8 ± 2.8BMI). Functional analyses of variance were used to compare vertical ground reaction force (vGRF), knee flexion angle (KFA), and internal knee extension moment (KEM) waveforms throughout stance phase of gait to determine the proportions of stance differing between limbs and groups.

RESULTS

Compared to uninjured controls, IL-6_High and MMP-3_High ACL subgroups demonstrated lesser vGRF (largest differences: IL-6, 7.88%BW; MMP-3, 11.05%BW) during early-stance and greater vGRF (largest differences: IL-6, 6.21%BW; MMP-3, 5.85%BW) in mid-stance, lesser KFA (largest differences: IL-6, 3.11°; MMP-3, 3.72°) and lesser KEM (largest differences: IL-6, 0.96%BW•m; MMP-3, 1.07%BW•m) in early-stance, as well as greater KFA in mid-stance (largest differences: IL-6, 1.5°; MMP-3, 2.95°).

CONCLUSIONS

High SF concentrations of a proinflammatory cytokine and a degradative enzyme early post-ACL injury are associated with aberrant gait biomechanics in the injured limb at 6 months post-ACLR (i.e., lesser vGRF, KFA and KEM) linked to posttraumatic osteoarthritis development.

Isokinetic knee strength deficit in patients with moderate haemophilia

INTRODUCTION

Knee joint bleedings are responsible for quadriceps atrophy and strength deficit in patients with severe haemophilia. Little is known about patients with moderate haemophilia (PWMH).

AIM

To evaluate isokinetic quadriceps and hamstrings strength in PWMH and to assess correlation with radiological and clinical parameter.

METHODS

18 PWMH aged 37.1 ± 11.4 and 18 healthy age-, weight- and height-matched controls performed a knee isokinetic test at 180°/s to assess quadriceps and hamstrings strength. In the PWMH group, knee Pettersson's score was pursued and Haemophilia Joint Health Score 2.1 (HJHS) was performed to determine unaffected knees (knee HJHS = 0) and affected ones (knee HJHS >0).

RESULTS

Affected knees had a decrease of quadriceps strength compared to controls, 1.26 ± 0.47 vs 1.64 ± 0.27 Nm/kg and a decrease of hamstring strength, 0.60 ± 0.29 vs 1.03 ± 0.21 Nm/kg, (P < 0.001). Unaffected knees also had a decrease of quadriceps strength compared to controls, 1.36 ± 0.31 vs 1.64 ± 0.27 Nm/kg and a decrease of hamstring strength, 0.69 ± 0.18 vs 1.03 ± 0.21 Nm/kg, (P < 0.001). The conventional hamstring-to-quadriceps ratio was significantly decreased in affected knees compared to controls, 0.46 ± 0.15 vs 0.64 ± 0.13 (P < 0.001) but also in unaffected knees, 0.53 ± 0.16 vs 0.64 ± 0.13 (P = 0.02).No correlation was found between strength and HJHS or Pettersson's score.

CONCLUSION

PWMH have a significant knee strength deficit, both on the quadriceps and the hamstrings, which is responsible for an important muscle imbalance.

Biomechanical analysis on total knee replacement patients during gait: Medial pivot or posterior stabilized design?

BACKGROUND

Total Knee Replacement surgery restores joint function in patients with advanced osteoarthritis. There are several prostheses available based on different mechanisms, which guarantee knee stability during Activities of Daily Living. The aim of this study is to compare ball-in-socket (or Medial Pivot) and post-cam mechanisms to detect possible differences in terms of biomechanical parameters between these two prosthesis designs and to evaluate which design is closer to physiological biomechanics.

METHODS

A kinematics, kinetics and electromyography lower limb analyses were performed during gait on sixty subjects: twenty with Medial Pivot prosthesis, twenty with posterior stabilized prosthesis and twenty healthy subjects to obtain a physiologic reference.

FINDINGS

Total Knee Replacement gait pattern for both patient groups were characterized by reduced walking speed, reduced stride length and increased stance time respect to control group. Comparison between Medial Pivot and Posterior Stabilized groups showed a reduction of knee flexion and flexor moment in patients with ball-in-socket mechanism. A prolonged muscular activity of rectus femoris was observed in Medial Pivot patients compared to Posterior Stabilized and control groups.

INTERPRETATION

"Stiff knee pattern" mechanism was showed for both patient groups but more enhanced in Medial Pivot patients. Even though the Posterior Stabilized design introduces the non-physiological paradoxical motion and the Medial Pivot design seems to better reproduce the physiological condylar movement as gait analysis parameters, including kinematics, kinetics and electromyographic parameters were closer to control group and, in turn, to physiological gait for the Posterior Stabilized than Medial Pivot group parameters.

Recurrent patellar dislocations in adolescents result in decreased knee flexion during the entire gait cycle

PURPOSE

To evaluate the kinematics/kinetics of the ankle, knee, hip in the sagittal plane in adolescents with recurrent patellar dislocation in comparison to a healthy control.

METHODS

Case-control study. Eighty-eight knees (67 patients) with recurrent patellar dislocation (mean age 14.8 years ± 2.8 SD) were compared to 54 healthy knees (27 individuals, 14.9 years  ± 2.4 SD). Kinematics/kinetics of ankle, knee, hip, and pelvis were captured using 3D-gait analysis (VICON, 12 cameras, 200 Hz, Plug-in-Gait, two force plates). One cycle (100%) consisted of 51 data-points. The mean of six trials was computed.

RESULTS

The loading-response increased by 0.02 s ± 0.01SE (10.8%) with dislocations (0.98% of total gait, P < 0.01). The mid-stance-phase decreased equally (P < 0.01). Dislocation decreased knee flexion during the entire gait cycle (P < 0.01), with the largest difference during mid-stance (9.0° ± 7.2 SD vs. 18.5° ± 6.7 SD). Dislocation increased plantar-flexion during loading response 4.1° ± 0.4 SE with (P < 0.01), afterward, the dorsal-extension decreased 3.2° ± 0.3 SE, (P < 0.01). Dislocation decreased hip flexion during all phases (P < 0.01). Maximal difference: 7.5° ± 0.5 SE during mid-stance. 80% of all patients developed this gait pattern. Internal moments of the ankle increased, of the knee and hip decreased during the first part of stance.

CONCLUSION

Recurrent patellar dislocation decreases knee flexion during the loading-response and mid-stance phase. A decreased hip flexion and increased plantar-flexion, while adjusting internal moments, indicate a compensation mechanism.

LEVEL OF EVIDENCE

III.

Knee effusion evaluated by ultrasonography warns knee osteoarthritis patients to develop their muscle atrophy: a three-year cohort study

This study aimed to elucidate the relationship between the quantitative value of suprapatellar effusion and the longitudinal changes in lower-extremity muscle mass (MM) in a cohort with knee osteoarthritis (KOA). Fifty-three subjects (106 legs) with bilateral radiographic KOA at baseline (BL) were enrolled. MM was calculated by bioimpedance analysis three times at BL, and at the one-year (1Y) and three-year (3Y) follow-ups. The longitudinal change in the lower-extremity MM was calculated by subtracting MM_BL from MM_1Y, and MM_1Y from MM_3Y. Subjects with ≥1.0 z-score loss were defined as having severe MM loss (SMML). Effusion was evaluated as the sagittal area of suprapatellar pouch (mm²) by ultrasonography. The ROC curve was drawn to determine the cut-off of effusion area. General estimating equations (GEEs) were conducted with the prevalence of SMML as the dependent variable and with the cut-off of effusion area as the independent variable. Sixteen legs (15.1%) demonstrated SMML_BL-1Y and another sixteen legs demonstrated SMML_1Y-3Y. GEEs revealed that individuals with ≥90 mm² effusion had significantly higher odds of SMML_BL-1Y prevalence (Odds ratio: 21.561; P-value: 0.003). Individuals with leachate knee effusion at BL had a significant risk of losing MM through the first year of the initial knee effusion assessment.

Acoustic Emissions as a Non-invasive Biomarker of the Structural Health of the Knee

The longitudinal assessment of joint health is a long-standing issue in the management of musculoskeletal injuries. The acoustic emissions (AEs) produced by joint articulation could serve as a biomarker for joint health assessment, but their use has been limited by a lack of mechanistic understanding of their creation. In this paper, we investigate that mechanism using an injury model in human lower-limb cadavers, and relate AEs to joint kinematics. Using our custom joint sound recording system, we recorded the AEs from nine cadaver legs in four stages: at baseline, after a sham surgery, after a meniscus tear, and post-meniscectomy. We compare the resulting AEs using their b-values. We then compare joint anatomy/kinematics to the AEs using the X-ray reconstruction of moving morphology (XROMM) technique. After the meniscus tear the number and amplitude of the AE peaks greatly increased from baseline and sham (b-value = 1.33 ± 0.15; p < 0.05). The XROMM analysis showed a close correlation between the minimal inter-joint distances (0.251 ± 0.082 cm during extension, 0.265 ± .003 during flexion, at 145°) and a large increase in the AEs. This work provides key insight into the nature of joint AEs, and details a novel technique and analysis for recording and interpreting these biosignals.

A prospective randomized trial examining the use of a closed suction drain shows no influence on strength or function in primary total knee arthroplasty

Aims

The aim of this study was to determine whether closed suction drain (CSD) use influences recovery of quadriceps strength and to examine the effects of drain use on secondary outcomes: quadriceps activation, intra-articular effusion, bioelectrical measure of swelling, range of movement (ROM), pain, and wound healing complications.

Patients and Methods

A total of 29 patients undergoing simultaneous bilateral total knee arthroplasty (TKA) were enrolled in a prospective, randomized blinded study. Patients were randomized to receive a CSD in one limb while the contralateral limb had the use of a subcutaneous drain (SCDRN) without the use of suction (‘sham drain’). Isometric quadriceps strength was collected as the primary outcome. Secondary outcomes consisted of quadriceps activation, intra-articular effusion measured via ultrasound, lower limb swelling measured with bioelectrical impendence and limb girth, knee ROM, and pain. Outcomes were assessed preoperatively and postoperatively at day two, two and six weeks, and three months. Differences between limbs were determined using paired Student’s t-tests or Wilcoxon’s signed-rank tests.

Results

No significant differences were identified between limbs prior to surgery for the primary or secondary outcomes. No significant differences in quadriceps strength were seen between CSD and SCDRN limbs at postoperative day two (p = 0.09), two weeks (primary endpoint) (p = 0.7), six weeks (p = 0.3), or three months (p = 0.5). The secondary outcome of knee extension ROM was significantly greater in the CSD limb compared with the SCDRN (p = 0.01) at two weeks following surgery, but this difference was absent at all other intervals. Secondary outcomes of quadriceps activation, intra-articular effusion, lower limb swelling, and pain were not found to differ significantly at any timepoint following surgery.

Conclusion

The use of CSD during TKA did not influence quadriceps strength, quadriceps activation, intra-articular effusion, lower limb swelling, ROM, or pain. These results have limited drain use by the authors in primary uncomplicated TKA. Cite this article: Bone Joint J 2019;101-B (7 Supple C):84–90

The relationship between lower extremity swelling, quadriceps strength, and functional performance following total knee arthroplasty

BACKGROUND

The relationships between swelling after total knee arthroplasty (TKA) and quadriceps strength and functional performance are poorly understood. Therefore, the aim of this study was to examine the relationships between lower extremity swelling, measured using bioelectrical impedance assessment (SF-BIA), and quadriceps strength and timed up and go (TUG) times following TKA.

METHODS

53 participants (64 ± 9.5 y/o, 43% male) undergoing primary unilateral TKA were recruited for the longitudinal observational study with repeated measures. Quantities of swelling were examined for contribution to two and six-week outcomes of strength and TUG time using hierarchical regression controlling for age, sex, and the baseline value of the dependent variable. Swelling was assessed using bioelectrical impedance assessment and quantified as the peak level of swelling and cumulative swelling (integral) over the post-TKA time window. Maximum isometric quadriceps strength (MVIC) was measured using a electromechanical dynamometer and participant functional performance measured using the TUG.

RESULTS

Neither peak swelling nor cumulative swelling significantly contributed to the variance of two-week quadriceps strength. At six weeks, peak swelling significantly improved the variance in maximal quadriceps strength by an additional four percent (p = 0.05), while cumulative swelling did not significantly contribute. Peak swelling significantly contributed to the variance in two-week (16%) and six-week (five percent) TUG times (p < 0.05), but the cumulative swelling did not.

CONCLUSIONS

Peak swelling represents a value of post-TKA swelling that is associated with strength and function. Reducing the peak level of swelling, occurring early after surgery, may improve patient functional recovery.

LEVEL OF EVIDENCE

Level II - Prospective observational study.

Evaluation of early musculoskeletal disease in patients with haemophilia: results from an expert consensus

: Early joint damage in patients with haemarthrosis often escapes diagnosis because of insufficient investigation of biomechanical changes. Arthropathy in haemophilia requires complex assessment with several tools. Considering the increased emphasis on an integrated approach to musculoskeletal (MSK) outcomes, re-evaluation of MSK assessment to address individual patient needs is warranted. To advise on the optimal use of current assessment tools and strategies for tailored MSK evaluation in patients with haemophilia. A panel of experts in haemophilic arthropathy evaluated internationally recognized assessment tools through published literature and personal expertise. Each tool was considered, scored and ranked for their utility in the clinical assessment of MSK damage. Subsequently, a patient evaluation table detailing advice on type and frequency of assessments for different patient populations was constructed. To obtain a complete MSK assessment, multiple tools must be used to ensure each criterion is evaluated. For patients with haemophilia, clinical examination of the joint, disease-specific structure/function scores, and activity/participation scores including quality of life are important, and should be performed on a regular basis according to age and clinical condition. Joint imaging is recommended in the prevention, diagnosis and follow-up of haemophilic arthropathy and should be used in conjunction with joint structure and function scores. An integrated approach to MSK assessment using combinations of tools will allow earlier management of dysfunction and may improve long-term outcomes. This approach could be used in long-term follow-up of all patients independent of age and disease stage, especially in children to prevent arthropathy.

A hierarchy in functional muscle roles at the knee is influenced by sex and anterior cruciate ligament deficiency

BACKGROUND

Sex-related neuromuscular differences have been linked to greater risk of anterior cruciate ligament injuries in females. Despite this, it remains unclear if sex-related differences are present after injury. This study sought to determine if sex differences are present in the functional roles of knee joint muscles in an anterior cruciate ligament deficient population.

METHODS

An isometric, weight-bearing, force-generation protocol required injured and healthy males and females to modulate ground reaction forces. Electromyography was used to classify the functional role of 10 lower limb muscles in their contribution to knee joint stability during various loading directions. These roles were compared between the four groups at 12 loading directions using a directional analysis.

FINDINGS

Functional muscle roles were different between groups, except for injured males and healthy females. Healthy males had either joint actuators or specific joint stabilisers, but no general stabilisers; the vastus medialis and lateralis of injured males and healthy females were classified as general stabilisers while injured females added the gluteus medialis and medial gastrocnemius as general stabilisers.

INTERPRETATION

A population-based hierarchy in functional muscle roles was discovered. Healthy males demonstrated the most specific muscle roles, which can be viewed as more adaptive to variable loading conditions. The more generalised stabilisation strategies seen in injured males and females would alter joint loading which may be detrimental to the knee joint health over time. In summary, (1) these injuries alter muscle roles; (2) these alterations are sex-specific; (3) rehabilitation might be optimised if sex-differences are considered.

Functional vs. Traditional Analysis in Biomechanical Gait Data: An Alternative Statistical Approach

In human motion studies, discrete points such as peak or average kinematic values are commonly selected to test hypotheses. The purpose of this study was to describe a functional data analysis and describe the advantages of using functional data analyses when compared with a traditional analysis of variance (ANOVA) approach. Nineteen healthy participants (age: 22 ± 2 yrs, body height: 1.7 ± 0.1 m, body mass: 73 ± 16 kg) walked under two different conditions: control and pain+effusion. Pain+effusion was induced by injection of sterile saline into the joint capsule and hypertonic saline into the infrapatellar fat pad. Sagittal-plane ankle, knee, and hip joint kinematics were recorded and compared following injections using 2×2 mixed model ANOVAs and FANOVAs. The results of ANOVAs detected a condition × time interaction for the peak ankle (F1,18 = 8.56, p = 0.01) and hip joint angle (F1,18 = 5.77, p = 0.03), but did not for the knee joint angle (F1,18 = 0.36, p = 0.56). The functional data analysis, however, found several differences at initial contact (ankle and knee joint), in the mid-stance (each joint) and at toe off (ankle). Although a traditional ANOVA is often appropriate for discrete or summary data, in biomechanical applications, the functional data analysis could be a beneficial alternative. When using the functional data analysis approach, a researcher can (1) evaluate the entire data as a function, and (2) detect the location and magnitude of differences within the evaluated function.

Muscle contributions to knee extension in the early stance phase in patients with knee osteoarthritis

The aim of this study was to analyze individual muscle contributions to knee angular acceleration using a musculoskeletal simulation analysis and evaluate knee extension mechanics in the early stance phase in patients with knee osteoarthritis (OA). The subjects comprised 15 patients with medial knee OA and 14 healthy elderly individuals. All participants underwent gait performance test using 8 infrared cameras and two force plates to measure the kinetic and kinematic data. The simulation was driven by 92 Hill-type muscle-tendon units of the lower extremities and a trunk with 23° of freedom. We analyzed each muscle contribution to knee angular acceleration in the 5%-15% and 15%-25% periods of the stance phase (% SP) using an induced acceleration analysis. We compared accelerations by individual muscles between the two groups using an analysis of covariance for controlling gait speed. Patients with knee OA had a significantly lesser knee extension acceleration by the vasti muscles and higher knee acceleration by hip adductors than those in controls in 5-15% SP. In addition, knee OA resulted in significantly lesser knee extension acceleration by the vasti muscles in 15-25% SP. These results indicate that patients with knee OA have decreased dependency on the vasti muscles to control knee movements during early stance phase. Hip adductor muscles, which mainly control mediolateral motion, partly compensate for the weak knee extension by the vasti muscles in patients with knee OA.

Gait adaptations following multiple-ligament knee reconstruction occur with altered knee kinematics during level walking

PURPOSE

The biomechanical behaviour of the knee following multiple-ligament reconstruction (MLKR) may play a role in the pathogenesis of post-traumatic osteoarthritis. The aim of this study was to compare three-dimensional knee kinematics and gait characteristics of MLKR patients to healthy controls during level walking.

METHODS

Three-dimensional optoelectronic motion capture during overground walking was performed on 16 patients with MLKR and a group of healthy controls matched individually to each patient for age, gender, height and weight. Three-dimensional knee angles were extracted from the weight acceptance and propulsion sub-phases of gait. Statistical analysis was performed using group-aggregated data, as well as for each patient-control pair using a single-case approach.

RESULTS

Although group analysis detected few differences, single-case analysis revealed significant differences for a proportion of patients for all dependent variables during weight acceptance and propulsion sub-phases of stance. These kinematic differences occurred in the context of reduced gait velocity, step length and cadence, as well as increased time spent in double support.

CONCLUSION

Patients with MLKR display abnormalities in knee kinematics during gait at an average of 4.5 years after surgery. The pattern of kinematic abnormalities appears individual specific and may not be related to differences in spatiotemporal gait characteristics. The current findings describe detailed functional outcomes of MLKR reconstruction at average medium-term follow-up that provide improved prognostic information for clinicians to counsel patients with these types of injuries.

Knee muscle activity during gait in patients with anterior cruciate ligament injury: a systematic review of electromyographic studies

PURPOSE

This review compared knee muscle activity between ACL-deficient (ACLD) patients and healthy controls during gait, to find out whether the available electromyography (EMG) studies support Quadriceps (Q-ceps) inhibition or hamstring facilitation during gait in ACLD patients.

METHOD

A systematic review was conducted to retrieve the EMG studies of knee muscles during gait in ACLD patients. Cochrane library, PubMed, Medline, Ovid, CINAHL and Science Direct databases were searched entries from 1995 through October 2014 using the terms "anterior cruciate ligament" OR "ACL", "electromyography" Or "EMG" "gait" Or "walking". Articles that assessed subjects with ACL rupture that used surface EMG to assess the knee muscle activity were included. The quality of the included papers was assessed using the Critical Appraisal Skills Programme tool for observational studies.

RESULT

In total, 13 studies met the inclusion criteria. Seven studies consistently found no significant difference in magnitude of activity or timing of Q-ceps muscle between the chronic ACLD patients and control subjects. Two studies on acute ACLD patients and three studies on ACLD patients with unstable knee found the significantly reduced Q-ceps activity compared to control subjects. Six studies showed the significantly greater hamstring activity, and three studies found prolonged duration of activity in ACLD patients compared to the control subjects.

CONCLUSION

This review highlighted that the results of the studies are in favour of increased hamstring muscular activity. However, decreased Q-ceps activation exists in the acute stage and in ACLD patients that experience knee instability (non-copers).

LEVEL OF EVIDENCE

III.

Rehabilitation Principles of the Anterior Cruciate Ligament Reconstructed Knee: Twelve Steps for Successful Progression and Return to Play

The rehabilitation process begins immediately after injury to the anterior cruciate ligament (ACL). The goal of preoperative rehabilitation is to prepare the patient for surgery. Current rehabilitation programs focus on strengthening exercises and proprioceptive and neuromuscular control drills to provide a neurologic stimulus. It is also important to address preexisting factors, especially for the female athlete, that may predispose to future injury, such as hip and hamstring weakness. Our goal in the rehabilitation program is to restore full, unrestricted function and to assist the patient to return to 100% of the preinjury level while achieving excellent long-term outcomes.

GAIT ANALYSIS: SYSTEMS, TECHNOLOGIES, AND IMPORTANCE

Human gait is the identity of a person's style and quality of life. Reliable cognition of gait properties over time, continuous monitoring, accuracy of evaluation, and proper analysis of human gait characteristics have demonstrated their importance not only in clinical and medical studies, but also in the field of sports, rehabilitation, training, and robotics research. Focusing on walking gait, this study presents an overview on gait mechanisms, common technologies used in gait analysis, and importance of this particular field of research. Firstly, available technologies that involved in gait analysis are briefly introduced in this paper by concentrating on the usability and limitations of the systems. Secondly, key gait parameters and motion characteristics are elucidated from four angles of views; one: gait phases and gait properties; two: center of mass and center of pressure (CoM-CoP) tracking profile; three: Ground Reaction Force (GRF) and impact, and four: muscle activation. Thirdly, the study focuses on the clinical observations of gait patterns in diagnosing gait abnormalities of impaired patients. The presentation also shows the importance of gait analysis in sports to improve performance as well as to avoid risk of injuries of sports personnel. Significance of gait analysis in robotic research is also illustrated in this part where the study focuses on robot assisted systems and its possible applicability in clinical rehabilitation and sports training.

Patellar instability and quadriceps avoidance affect walking knee moments

PURPOSE

To classify patients with patellofemoral (PF) instability on the basis of their mechanical gait characteristics, and to relate gait deficits to patellofemoral congruence.

METHODS

Thirteen patients awaiting patellar stabilisation surgery were recruited for gait analysis and magnetic resonance imaging, MRI assessment of PF congruence. Patients were grouped into two subgroups (P1, P2) based on knee joint moment during stance, and their total support moments (TSMs) during stance were compared against eight healthy Control subjects. PF congruence was compared between groups from MRI data captured at 0, 20 and 40° of passive knee flexion and during dynamic extension.

RESULTS

Five patients were classified into group P1 because they demonstrated a knee extensor moment during early stance, and eight patients into group P2 because they did not. The TSM of the more affected limb in group P1 was not significantly different from Control values in early stance but the difference was significant (P<.05) in late stance. In group P2, both the less and more affected limbs were significantly different from Control TSM values in early stance, but only the more affected limb in late stance. Patellofemoral contact areas as measured by MRI were greatest for the Control patients, and least for patient group P2 especially during the active extension trials.

CONCLUSIONS

Patients with patellofemoral pain and instability walked with a slightly flexed knee, avoiding extension. The MRI measurements of joint contact agreed with the patient groupings according to gait mechanics. Cartilage contact across the PF joint can be an objective measure of instability.

Post-operative bracing after ACL reconstruction has no effect on knee joint effusion. A prospective, randomized study

BACKGROUND

It is unclear what factors contribute to knee joint effusion after anterior cruciate ligament (ACL) injury and reconstruction. Knee homeostasis after injury and surgery is crucial for rehabilitation and knee well-being. We examined if effusion was affected by post-operative bracing, and if patients with effusion fit into a common profile.

METHODS

Patients were randomized to wearing or not wearing a post-operative brace for three weeks after ACL reconstruction with semitendinosus-gracilis tendons. Knee joint effusion was detected by computed tomography in 60 patients (22 women), before and three and 12 months after surgery. Joint effusion, clinical and subjective tests were analyzed.

RESULTS

This is the first prospective, randomized study on post-operative bracing for patients with a semitendinosus-gracilis graft showed that bracing had no effect on three-months presence of joint effusion. Excessive joint effusion was present in 68% of the patients three months after surgery and was associated to prior meniscus injury (p=0.05) and higher prior Tegner activity level (p=0.006). We found a positive association between longer time from injury to surgery and joint effusion three months post-operatively (rho=0.29, p<0.05). Twelve months post-operatively, joint effusion had diminished to baseline levels. Subjective scores and activity levels were lower for women. Three-months joint effusion predicted lower final outcome scores in women.

CONCLUSION

Prior meniscus injury and pre-injury Tegner activity levels are predictive significant variables for excessive knee joint effusion after ACL reconstruction. Post-operative bracing had no effect. A larger clinical cohort is needed to confirm findings of this logistic regression.

Effects of joint effusion on quadriceps muscles in patients with knee osteoarthritis

OBJECTIVES

To evaluate the effect of knee effusion on the quadriceps muscle in patients with knee osteoarthritis (OA).

DESIGN

Single-blind, randomized, controlled clinical trial.

SETTING

Single medical center.

PARTICIPANTS

Forty subjects with knee OA were assigned to a experimental (n = 20) or control (n = 20) group.

MAIN OUTCOME MEASURES

Quadriceps torque and root mean square (RMS) values of surface electromyography (EMG) of the vastus medialis and vastus lateralis muscles were measured during a maximal isometric contraction at 60° knee flexion. Thereafter, 20 mL of normal saline was injected into the knee joint of the experimental group. Quadriceps torque and RMS values were again measured.

RESULTS

Five subjects did not complete the study. No significant difference in quadriceps peak torque or RMS of EMG activity was observed at baseline, pre-effusion, or post-effusion measures in either group. The experimental group showed no significant change in quadriceps peak torque or RMS of EMG activity in any period compared with the control group.

CONCLUSIONS

These results demonstrate that a 20 ml joint effusion did not affect peak torque or RMS values of the quadriceps muscle in patients with knee OA.

Immediate Effects of Kinesiology Taping of Quadriceps on Motor Performance after Muscle Fatigued Induction

Objectives. The purpose of this cross-sectional single-blind study was to investigate the immediate effects of Kinesiology taping of quadriceps on motor performance after muscle fatigued induction. Design. Randomized controlled cross-sectional design. Subjects. Forty-five subjects participated in this study. Participants were divided into three groups: Kinesiology taping group, placebo taping group, and nontaping group. Methods. Subjects performed short-term exercise for muscle fatigued induction, followed by the application of each intervention. Peak torque test, one-leg single hop test, active joint position sense test, and one-leg static balance test were carried out before and after the intervention. Results. Peak torque and single-leg hopping distance were significantly increased when Kinesiology taping was applied (p < 0.05). But there were no significant effects on active joint position sense and single-leg static balance. Conclusions. We proved that Kinesiology taping is effective in restoring muscle power reduced after muscle fatigued induction. Therefore, we suggest that Kinesiology taping is beneficial for fatigued muscles.

Bioimpedance spectroscopy for swelling evaluation following total knee arthroplasty: a validation study

BACKGROUND

The evaluation of swelling is important for the outcome of total knee arthroplasty (TKA) surgery. The circumference or volume measurements are applicable at the bedside of the patient but are altered by muscular atrophy and the post-surgical dressing. Bioimpedance spectroscopy might overcome these limitations; however, it should be validated. This study aimed to explore the validity, the reliability and the responsiveness of bioimpedance spectroscopy for measuring swelling after TKA.

METHODS

The degree of swelling in 25 patients undergoing TKA surgery was measured using bioimpedance spectroscopy (BIS R0), knee circumference and limb volume. The measurements were performed on D-1 (day before surgery), D + 2 (2 days after surgery) and D + 8 (8 days after surgery). The BIS R0 measurements were repeated twice, alternating between two evaluators. The percentage of the difference between the limbs was calculated for BIS R0, circumference and volume. The intra- and inter-observer intraclass correlation coefficients (ICCs), limits of agreement (LOA), effect size (Cohen's d), correlations between the methods and diagnostic sensitivity were calculated.

RESULTS

BIS R0, circumference and volume detected swelling < 3.5% at D-1. The swelling at D2 and D8 was greater with BIS R0 [mean (SD) 29.9% (±9.8) and 38.27 (±7.8)] than with volume [14.7 (±9.5) and 14.9 (±8.2)] and circumference [11.1 (±5.7) and 11.7 (±4.1)]. The BIS R0 intra- and inter-evaluator ICCs ranged from 0.89 to 0.99, whereas the LOA were < 5.2%. The BIS R0 correlation was 0.73 with volume and 0.75 with circumference. The BIS R0 Cohen's d was 3.32 for the D-1-D2 evolution. The diagnostic sensitivity was 83% D2 and 96% at D8.

CONCLUSION

Bioimpedance is a valid method for the evaluation of swelling following TKA. BIS R0 also demonstrated excellent intra- and inter-evaluator reliability. The diagnostic sensitivity and responsiveness is superior to that of concurrent methods. BIS R0 is an efficient method for post-surgical follow up at the bedside of the patient. The measurement of BIS R0 is a straightforward, valid, reliable and responsive method for lower limb swelling following TKA surgery that could be used in clinics and research.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00627770.

Neural Excitability Alterations After Anterior Cruciate Ligament Reconstruction

CONTEXT

Neuromuscular dysfunction is common after anterior cruciate ligament reconstruction (ACL-R). However, little is known about quadriceps spinal-reflex and descending corticomotor excitability after ACL-R. Understanding the effects of ACL-R on spinal-reflex and corticomotor excitability will help elucidate the origins of neuromuscular dysfunction.

OBJECTIVE

To determine whether spinal-reflex excitability and corticomotor excitability differed between the injured and uninjured limbs of patients with unilateral ACL-R and between these limbs and the matched limbs of healthy participants.

DESIGN

Case-control study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 28 patients with unilateral ACL-R (9 men, 19 women; age = 21.28 ± 3.79 years, height = 170.95 ± 10.04 cm, mass = 73.18 ± 18.02 kg, time after surgery = 48.10 ± 36.17 months) and 29 participants serving as healthy controls (9 men, 20 women; age = 21.55 ± 2.70 years, height = 170.59 ± 8.93 cm, mass = 71.89 ± 12.70 kg) volunteered.

MAIN OUTCOME MEASURE(S)

Active motor thresholds (AMTs) were collected from the vastus medialis (VM) using transcranial magnetic stimulation. We evaluated VM spinal reflexes using the Hoffmann reflex normalized to maximal muscle responses (H : M ratio). Voluntary quadriceps activation was measured with the superimposed-burst technique and calculated using the central activation ratio (CAR). We also evaluated whether ACL-R patients with high or low voluntary activation had different outcomes.

RESULTS

The AMT was higher in the injured than in the uninjured limb in the ACL-R group (t27 = 3.32, P = .003) and in the matched limb of the control group (t55 = 2.05, P = .04). The H : M ratio was bilaterally higher in the ACL-R than the control group (F1,55 = 5.17, P = .03). The quadriceps CAR was bilaterally lower in the ACL-R compared with the control group (F1,55 = 10.5, P = .002). The ACL-R group with low voluntary activation (CAR < 0.95) had higher AMT than the control group (P = .02), whereas the ACL-R group with high voluntary activation (CAR ≥ 0.95) demonstrated higher H : M ratios than the control group (P = .05).

CONCLUSIONS

The higher VM AMT in the injured limbs of ACL-R patients suggested that corticomotor deficits were present after surgery. Higher bilateral H : M ratios in ACL-R patients may be a strategy to reflexively increase excitability to maintain voluntary activation.

Quadriceps corticomotor excitability following an experimental knee joint effusion

PURPOSE

Deficits in quadriceps strength and voluntary activation are common following knee injury. These deficits are hypothesized to generate from a neural level, however, it remains unclear how corticomotor pathways are affected following acute injury. The purpose of this investigation was to examine whether corticomotor alterations of the quadriceps were present following a simulated knee joint injury using an experimental effusion model.

METHODS

Participants completed two testing sessions, an experimental knee effusion and control session, separated by 7 days. The central activation ratio was used to assess change in quadriceps activation. Corticomotor excitability was assessed pre- and post-intervention via active motor thresholds (AMTs) and motor evoked potentials (MEPs) normalized to maximal muscle responses. MEPs were assessed at different percentages of AMT, and associated slopes between these percentages were analysed. Paired-sample t tests were performed on percentage change scores calculated from pre-intervention outcome measures to assess change in corticomotor excitability and changes in the slope of MEP values as percentage of AMT increased.

RESULTS

Quadriceps activation significantly decreased during the effusion session. AMT and MEP change scores were not different between effusion and control conditions. No substantial differences were found in slope between any percentages of AMT.

CONCLUSIONS

An experimental knee effusion did not induce changes in corticomotor excitability. Further research is needed to understand how corticomotor pathways are affected following joint injury. Corticomotor excitability alterations may not be the cause of acute changes in neuromuscular activation following joint effusion. Future research should determine whether clinically altering corticomotor excitability will improve physical function.

LEVEL OF EVIDENCE

II.

Quadriceps neural alterations in anterior cruciate ligament reconstructed patients: A 6-month longitudinal investigation

The purpose of this investigation was to evaluate differences in quadriceps corticospinal excitability, spinal-reflexive excitability, strength, and voluntary activation before, 2 weeks post and 6 months post-anterior cruciate ligament reconstruction (ACLr). This longitudinal, case-control investigation examined 20 patients scheduled for ACLr (11 females, 9 males; age: 20.9 ± 4.4 years; height:172.4 ± 7.5 cm; weight:76.2 ± 11.8 kg) and 20 healthy controls (11 females, 9 males; age:21.7 ± 3.7 years; height: 173.7 ± 9.9 cm; weight: 76.1 ± 19.7 kg). Maximal voluntary isometric contractions (MVIC), central activation ratio (CAR), normalized Hoffmann spinal reflexes, active motor threshold (AMT), and normalized motor-evoked potential (MEP) amplitudes at 120% of AMT were measured in the quadriceps muscle at the specific time points. ACLr patients demonstrated bilateral reductions in spinal-reflexive excitability compared with controls before surgery (P = 0.02) and 2 weeks post-surgery (P ≤ 0.001). ACLr patients demonstrated higher AMT at 6 months post-surgery (P ≤ 0.001) in both limbs. No MEP differences were detected. Quadriceps MVIC and CAR were lower in both limbs of the ACLr group before surgery and 6 months post-surgery (P ≤ 0.05) compared with controls. Diminished excitability of spinal-reflexive and corticospinal pathways are present at different times following ACLr and occur in combination with clinical deficits in quadriceps strength and activation. Early rehabilitation strategies targeting spinal-reflexive excitability may help improve postoperative outcomes, while later-stage rehabilitation may benefit from therapeutic techniques aimed at improving corticospinal excitability.

Persistent neuromuscular and corticomotor quadriceps asymmetry after anterior cruciate ligament reconstruction

CONTEXT

Return to activity in the presence of quadriceps dysfunction may predispose individuals with anterior cruciate ligament reconstruction (ACLR) to long-term joint degeneration. Asymmetry may manifest during movement and result in altered knee-joint-loading patterns; however, the underlying neurophysiologic mechanisms remain unclear.

OBJECTIVE

To compare limb symmetry of quadriceps neuromuscular function between participants with ACLR and participants serving as healthy controls.

DESIGN

Descriptive laboratory study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 22 individuals with ACLR (12 men, 10 women) and 24 individuals serving as healthy controls (12 men, 12 women).

MAIN OUTCOME MEASURE(S)

Normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg), quadriceps central activation ratio (CAR) (%), quadriceps motor-neuron-pool excitability (Hoffmann reflex to motor wave ratio), and quadriceps active motor threshold (AMT) (% 2.0 T) were measured bilaterally and used to calculate limb symmetry indices for comparison between groups. We used analyses of variance to compare quadriceps Hoffmann reflex to motor wave ratio, normalized knee-extension MVIC torque, quadriceps CAR, and quadriceps AMT between groups and limbs.

RESULTS

The ACLR group exhibited greater asymmetry in knee-extension MVIC torque (ACLR group = 0.85 ± 0.21, healthy group = 0.97 ± 0.14; t44 = 2.26, P = .03), quadriceps CAR (ACLR group = 0.94 ± 0.11, healthy group = 1.00 ± 0.08; t44 = 2.22, P = .04), and quadriceps AMT (ACLR group = 1.13 ± 0.18, healthy group = 1.02 ± 0.11; t34 = -2.46, P = .04) than the healthy control group.

CONCLUSIONS

Asymmetries in measures of quadriceps function and cortical excitability were present in patients with ACLR. Asymmetry in quadriceps strength, activation, and cortical excitability persisted in individuals with ACLR beyond return to recreational activity. Measuring the magnitude of asymmetry after ACLR represents an important step in understanding long-term reductions in self-reported function and increased rate of subsequent joint injury in otherwise healthy, active individuals after ACLR.

Changes in voluntary quadriceps activation predict changes in muscle strength and gait biomechanics following knee joint effusion

BACKGROUND

It has been hypothesized that arthrogenic muscle inhibition is responsible for altering physical function following knee injury. The association between the onset of arthrogenic muscle inhibition, measured using voluntary quadriceps activation, and changes in muscle strength and gait biomechanics are unknown.

METHODS

Outcomes were collected before and following a 60 ml experimental knee effusion in eighteen healthy participants. Voluntary quadriceps activation was the predictor variable, while the criterion variable included, maximal voluntary isometric strength, peak knee flexion angle, peak internal knee extension moment, and peak vertical ground reaction forces during the first half of stance phase upon stair descent. Percent change scores (Δ) were imputed into linear regression equations to determine associations between predictor and criterion variables.

FINDINGS

The variance in Δ voluntary quadriceps activation significantly predicted 87% the variance in the Δ strength (R(2)=0.87, P<0.001; Δ strength=-2.15+1.77Δ voluntary quadriceps activation) and 25% of the Δ vertical ground reaction force following effusion (R(2)=0.25, P=0.04; Δ vertical ground reaction force=-6.1+0.57 Δ voluntary quadriceps activation). After accounting for Δ knee flexion angle, Δ voluntary quadriceps activation predicted an additional 29% (Δ R(2)=0.29, P=0.007) of the variance in the Δ knee extension moment (R(2)=0.54, P=0.003, Δ knee extension moment=-10.79+0.74Δ knee flexion angle+1.64Δ voluntary quadriceps activation) following knee effusion.

INTERPRETATION

Immediate quadriceps activation deficits following joint effusion result in immediate alterations in muscle strength, knee extensor moment and vertical ground reaction force during gait.

Intra-articular pressures and joint mechanics: should we pay attention to effusion in knee osteoarthritis?

What factors play a role to ensure a knee joint does what it should given the demands of moving through the physical environment? This paper aims to probe the hypothesis that intra-articular joint pressures, once a topic of interest, have been left aside in contemporary frameworks in which we now view knee joint function. The focus on ligamentous deficiencies and the chondrocentric view of osteoarthritis, while important, have left little attention to the consideration of other factors that can impair joint function across the lifespan. Dynamic knee stability is required during every step we take. While there is much known about the role that passive structures and muscular activation play in maintaining a healthy knee joint, this framework does not account for the role that intra-articular joint pressures may have in providing joint stability during motion and how these factors interact. Joint injuries invariably result in some form of intra-articular fluid accumulation. Ultimately, it may be how the knee mechanically responds to this fluid, of which pressure plays a significant role that provides the mechanisms for continued function. Do joint pressures provide an important foundation for maintaining knee function? This hypothesis is unique and argues that we are missing an important piece of the puzzle when attempting to understand implications that joint injury and disease have for joint function.

Clinically-relevant measures associated with altered contact forces in patients with anterior cruciate ligament deficiency

BACKGROUND

Knee joint contact forces are altered after anterior cruciate ligament injury during walking and may be related to clinically-relevant measures of impairments or self-reported function. The purpose of this study was to investigate the association of several clinically-relevant measures with altered knee contact forces in patients with anterior cruciate ligament injury.

METHODS

Data for this study represent a cross-sectional observational analysis of thirty-seven (23 M, 14 F) patients with complete unilateral anterior cruciate ligament injury. Gait analysis with electromyography was used to obtain estimates of tibiofemoral joint contact force using an electromyography-driven musculoskeletal model. Multivariable linear regression was used to identify measures associated with tibiofemoral joint contact force.

FINDINGS

Involved knee extensor muscle strength and patient-reported knee function on the Global Rating Scale of perceived function were significantly associated with peak tibiofemoral contact force for the involved limb. Patients who were stronger and who perceived higher knee function walked with greater contact forces on their involved knees. After controlling for walking speed, involved extensor strength explained 8.9% of the variance in involved peak tibiofemoral contact force and score on the Global Rating Scale explained an additional 9.4% of the variance.

INTERPRETATION

Improvements in involved quadriceps strength and overall function as measured by patient self-report may be important for increasing involved limb contact forces, thereby restoring loading symmetry in these patients who demonstrate decreased involved limb loading after injury. These results highlight the potential value of studying the recovery of strength, self-reported function and joint loading symmetry in patients with anterior cruciate ligament injury.

Manual therapy directed at the knee or lumbopelvic region does not influence quadriceps spinal reflex excitability

Manual therapies, directed to the knee and lumbopelvic region, have demonstrated the ability to improve neuromuscular quadriceps function in individuals with knee pathology. It remains unknown if manual therapies may alter impaired spinal reflex excitability, thus identifying a potential mechanism in which manual therapy may improve neuromuscular function following knee injury.

AIM

To determine the effect of local and distant mobilisation/manipulation interventions on quadriceps spinal reflex excitability.

METHODS

Seventy-five individuals with a history of knee joint injury and current quadriceps inhibition volunteered for this study. Participants were randomised to one of five intervention groups: lumbopelvic manipulation (grade V), lumbopelvic manipulation positioning (no thrust), grade IV patellar mobilisation, grade I patellar mobilisation, and control (no treatment). Changes in spinal reflex excitability were quantified by assessing the Hoffmann reflex (H-reflex), presynaptic, and postsynaptic excitability. A hierarchical linear-mixed model for repeated measures was performed to compare changes in outcome variables between groups over time (pre, post 0, 30, 60, 90 min).

RESULTS

There were no significant differences in H-reflex, presynaptic, or postsynaptic excitability between groups across time.

CONCLUSIONS

Manual therapies directed to the knee or lumbopelvic region did not acutely change quadriceps spinal reflex excitability. Although manual therapies may improve impairments and functional outcomes the underlying mechanism does not appear to be related to changes in spinal reflex excitability.

Disinhibitory interventions and voluntary quadriceps activation: a systematic review

OBJECTIVE

To determine the effects of various therapeutic interventions on increasing voluntary quadriceps muscle activation.

BACKGROUND

Decreased voluntary quadriceps activation is commonly associated with knee injury. Recently, research has focused on developing specific disinhibitory interventions to improve voluntary quadriceps activation; yet, it remains unknown which interventions are most effective in promoting this improvement.

DATA SOURCES

We searched Web of Science from January 1, 1965 through September 27, 2012, using the key words quadriceps activation and transcutaneous electrical nerve stimulation, transcranial magnetic stimulation, cryotherapy, focal joint cooling, joint mobilization, joint mobilisation, joint manipulation, manual therapy, and neuromuscular electrical stimulation.

STUDY SELECTION

Studies evaluating the effect of disinhibitory interventions on volitional quadriceps activation were used in our review. Standardized effect sizes (Cohen d) and 95% confidence intervals (CIs) were calculated from voluntary quadriceps activation means and standard deviations measured at baseline and at all available postintervention time points from each study.

DATA SYNTHESIS

Ten studies were grouped into 5 categories based on intervention type: manual therapy (4 studies), transcutaneous electrical nerve stimulation (2 studies), cryotherapy (2 studies), neuromuscular electrical stimulation (2 studies), and transcranial magnetic stimulation (1 study). Transcutaneous electrical nerve stimulation demonstrated the strongest immediate effects (d = 1.03; 95% CI = 0.06, 1.92) and long-term effects (d = 1.93; 95% CI = 0.91, 2.83). Cryotherapy (d = 0.76; 95% CI = -0.13, 1.59) and transcranial magnetic stimulation (d = 0.54; 95% CI = -0.33, 1.37) had moderate immediate effects in improving voluntary quadriceps activation, whereas manual therapy (d = 0.38; 95% CI = -0.35, 1.09) elicited only weak immediate effects. Neuromuscular electrical stimulation produced weak negative to strong positive effects (range of d values = -0.50 to 1.87) over a period of 3 weeks to 6 months.

CONCLUSIONS

Transcutaneous electrical nerve stimulation demonstrated the strongest and most consistent effects in increasing voluntary quadriceps activation and may be the best disinhibitory intervention for improving the same.

Quadriceps intramuscular fat fraction rather than muscle size is associated with knee osteoarthritis

OBJECTIVES

To compare thigh muscle intramuscular fat (intraMF) fractions and area between people with and without knee radiographic osteoarthritis (ROA); and to evaluate the relationships of quadriceps adiposity and area with strength, function and knee magnetic resonance imaging (MRI) lesions.

METHODS

Ninety six subjects (ROA: Kellgren-Lawrence (KL) > 1; n = 30, control: KL = 0, 1; n = 66) underwent 3-T MRI of the thigh muscles using chemical shift-based water/fat MRI (fat fractions) and the knee (clinical grading). Subjects were assessed for isometric/isokinetic quadriceps/hamstrings strength, function Knee injury and Osteoarthritis Outcome Score (KOOS), stair climbing test (SCT), and 6-minute walk test (6MWT). Thigh muscle intraMF fractions, muscle area and strength, and function were compared between controls and ROA subjects, adjusting for age. Relationships between measures of muscle fat/area with strength, function, KL and lesion scores were assessed using regression and correlational analyses.

RESULTS

The ROA group had worse KOOS scores but SCT and 6MWT were not different. The ROA group had greater quadriceps intraMF fraction but not for other muscles. Quadriceps strength was lower in ROA group but the area was not different. Quadriceps intraMF fraction but not area predicted self-reported disability. Aging, worse KL, and cartilage and meniscus lesions were associated with higher quadriceps intraMF fraction.

CONCLUSION

Quadriceps intraMF is higher in people with knee OA and is related to symptomatic and structural severity of knee OA, whereas the quadriceps area is not. Quadriceps fat fraction from chemical shift-based water/fat MR imaging may have utility as a marker of structural and symptomatic severity of knee OA disease process.

Influência de diferentes tipos de calçado na atividade eletromiográfica do músculo quadríceps de mulheres ao subir e descer degrau

INTRODUÇÃO: A síndrome da dor femoropatelar (SDFP) é caracterizada por dor difusa na região retropatelar, aumentada durante realização de tarefas diárias, tais como subir e descer escadas e ajoelhar. A SDFP tem maior prevalência em mulheres jovens e sua etiologia não é totalmente conhecida. OBJETIVO: Avaliar a influência do uso de diferentes tipos de calçados na atividade dos músculos estabilizadores da patela durante as tarefas de subir e descer degrau. MATERIAIS E MÉTODOS: Participaram do estudo dez mulheres saudáveis e dez mulheres com SDFP. As voluntárias realizaram as tarefas de subir e descer um degrau em três situações: descalças, usando tênis e salto alto de 10 cm. Durante a realização das tarefas, foi registrada com eletrodos superficiais a atividade eletromiográfica dos músculos vasto medial oblíquo (VMO), vasto lateral (VL) e reto femoral (RF). A comparação intergrupos foi realizada com o teste t não pareado; para a análise intragrupo, utilizou-se ANOVA com medidas repetidas e post hoc Tukey, todos com um nível de significância de 5%. RESULTADOS: Os resultados demonstraram, no grupo controle, aumento da atividade do VMO nas tarefas concêntrica e excêntrica realizadas com salto alto. No entanto, no grupo SDFP, a atividade do VMO não foi influenciada em nenhuma das condições testadas. Não foram observadas diferenças estatísticas na razão VMO/VL e no tempo de ativação dos músculos. CONCLUSÃO: Os resultados sugerem que em mulheres assintomáticas uso do calçado de salto alto modificou a atividade de todos os músculos. Entretanto, mulheres com SDFP não apresentaram alterações no VMO.