An electromyographic exploratory study comparing the difference in the onset of hamstring and quadriceps contraction in patients with anterior knee pain

Metabolic syndrome reduces spinal range of motion: The Yakumo study

BACKGROUND

Excess visceral fat can accumulate owing to lack of exercise. The relationship between metabolic syndrome (MetS) and spinal range of motion (ROM) is not clear. The purpose of this study was to investigate the relationship between MetS and spinal alignment and ROM.

METHODS

Orthopedic evaluation was prospectively performed in 544 participants. The participants were classified into two groups on the basis of the Japanese-specific MetS criteria proposed by the Japanese Committee of the Criteria for MetS (JCCMS). Lower back pain (LBP), knee joint pain with the visual analog scale (VAS), Kellgren-Lawrence (K-L) grade for knee osteoarthritis, body mass index (BMI), and spinal alignment and ROM were evaluated.

RESULTS

Forty-four (8.1%) were diagnosed as having MetS. The prevalence rate of K-L grade 4 in the MetS group was significantly higher than that in the non-MetS group (p < 0.05). When sex, age, and BMI were evaluated as covariates, there were significant differences in the VAS score for knee pain (non-MetS group vs MetS group: 13.7 vs 23.3, p < 0.05), L1-S1 flexion spinal ROM (44.1° vs 38.1°, p < 0.001), flexion spinal inclination angle (SIA) ROM (107.6° vs 99.3°, p < 0.01), and SIA ROM (135.4° vs 124.0°, p < 0.05).

CONCLUSIONS

Knee pain increased and flexion spinal ROM decreased significantly in the MetS group as compared with non-MetS group. Systemic factors associated with MetS may have a specific impact on spinal ROM while promoting knee osteoarthrosis and increased knee pain.

Local neuromuscular characteristics associated with patellofemoral pain: A systematic review and meta-analysis

BACKGROUND

Local neuromuscular deficits have been reported in people with patellofemoral pain. We synthesised the neuromuscular characteristics associated with patellofemoral pain to help identify interventional targets and potential mechanisms.

METHODS

Five databases were searched for local neuromuscular characteristics in case-control studies. Electromyography, flexibility, muscle performance and cross-sectional area data were derived from functional or isolated task investigations and synthesised accordingly. An evidence gap map was constructed.

FINDINGS

Sixty-seven studies were included. In functional tasks, electromyographic investigations showed moderate evidence of small effect for vastus medialis onset-delays relative to vastus lateralis (0.44 [0.03, 0.85]) during stepping/stair negotiation tasks, and higher biceps femoris mean excitation amplitudes (0.55 [0.06, 1.04]) in single-leg triple-hop test. In isolated tasks, we found moderate evidence of medium effect for lower Hoffman-reflex amplitude of vastus medialis (-1.12 [-1.56, -0.67]). Muscle performance investigations showed; strong evidence with medium and small effects for lower extensors concentric (-0.61 [-0.81, -0.40]) and eccentric (-0.56 [-0.79, -0.33]) strength, and moderate evidence of medium effect of lower isometric (-0.64 [-0.87, -0.41]) strength, moderate evidence with small effect for rate of force development to 30% (-0.55[-0.89, -0.21]), 60% (-0.57[-0.90, -0.25]) and medium effect to 90% (-0.76[-1.43, -0.10]) of maximum voluntary contraction, and small effect for lower flexors concentric strength (-0.46 [-0.74, -0.19]) and extensors total work (-0.48 [-0.90, -0.07]). Flexibility investigations showed tighter hamstrings (-0.57 [-0.99, -0.14]).

INTERPRETATION

Differences within quadriceps and hamstrings motor-control, hamstrings tightness, and quadriceps and hamstrings weakness are associated with patellofemoral pain, and can be used to guide investigations of treatment effects.

Muscle Function and Kinematics during Submaximal Equine Jumping: What Can Objective Outcomes Tell Us about Athletic Performance Indicators?

Selection and training practices for jumping horses have not yet been validated using objective performance analyses. This study aimed to quantify the differences and relationships between movement and muscle activation strategies in horses with varying jump technique to identify objective jumping performance indicators. Surface electromyography (sEMG) and three-dimensional kinematic data were collected from horses executing a submaximal jump. Kinematic variables were calculated based on equestrian-derived performance indicators relating to impulsion, engagement and joint articulation. Horses were grouped using an objective performance indicator-center of mass (CM) elevation during jump suspension (Z_CM). Between-group differences in kinematic variables and muscle activation timings, calculated from sEMG data, were analyzed using one-way ANOVA. Statistical parametric mapping (SPM) evaluated between-group differences in time and amplitude-normalized sEMG waveforms. Relationships between movement and muscle activation were evaluated using Pearson correlation coefficients. Horses with the greatest Z_CM displayed significantly (p < 0.05) shorter gluteal contractions at take-off, which were significantly correlated (p < 0.05) with a faster approach and more rapid hindlimb shortening and CM vertical displacement and velocity, as well as shorter hindlimb stance duration at take-off. Findings provide objective support for prioritizing equestrian-derived performance indicators related to the generation of engagement, impulsion and hindlimb muscle power when selecting or training jumping horses.

Is There a Biomechanical Link Between Patellofemoral Pain and Osteoarthritis? A Narrative Review

The patellofemoral (PF) joint is the knee compartment most commonly affected by osteoarthritis (OA). Even mild PF OA is associated with considerable pain and functional limitations. Despite its prevalence and impact, little is understood of the etiology or structural and functional features of PF OA. The clinical symptoms of PF OA, such as anterior knee pain during stair ambulation and squatting, share many similarities with PF pain in adolescents and young adults. PF joint OA is most commonly diagnosed in people aged >40 years, many of whom report a history of PF pain. As such, there is growing evidence that PF pain and PF OA form a continuum of disease. This review explores the possible relationship between the presence of PF pain and the development of PF OA. We review the evidence for altered neuromotor control and biomechanical factors that may be associated with altered PF loading in people with PF pain and PF OA. In doing so, we highlight similarities and differences that may evolve along the continuum. By improving our understanding of the neuromotor and biomechanical links between PF pain and PF OA, we may highlight potential targets for new rehabilitation strategies.

Patellofemoral pain in athletes

Patellofemoral pain (PFP) is a frequent cause of anterior knee pain in athletes, which affects patients with and without structural patellofemoral joint (PFJ) damage. Most younger patients do not have any structural changes to the PFJ, such as an increased Q angle and a cartilage damage. This clinical entity is known as patellofemoral pain syndrome (PFPS). Older patients usually present with signs of patellofemoral osteoarthritis (PFOA). A key factor in PFPS development is dynamic valgus of the lower extremity, which leads to lateral patellar maltracking. Causes of dynamic valgus include weak hip muscles and rearfoot eversion with pes pronatus valgus. These factors can also be observed in patients with PFOA. The available evidence suggests that patients with PFP are best managed with a tailored, multimodal, nonoperative treatment program that includes short-term pain relief with nonsteroidal anti-inflammatory drugs (NSAIDs), passive correction of patellar maltracking with medially directed tape or braces, correction of the dynamic valgus with exercise programs that target the muscles of the lower extremity, hip, and trunk, and the use of foot orthoses in patients with additional foot abnormalities.

Reliability of electromyography parameters during stair deambulation in patellofemoral pain syndrome

Reliability is essential to all aspects of the measure, as it shows the quality of the information and allows rational conclusions with regard to the data. There has been controversial results regarding the reliability of electromyographic parameters assessed during stair ascent and descent in individuals with patellofemoral pain syndrome (PFPS). Therefore, this study aims to determine the reliability of time and frequency domain electromyographic parameters on both gestures in women with PFPS. Thirty-one women with PFPS were selected to participate in this study. Data from vastus lateralis and medialis were collected during stair deambulation. The selected parameters were: automatic onset, median frequency bands of low, medium and high frequency. Reliability was determined by intraclass correlation coefficient and the standard error of measurement. The frequency domain variables have shown good reliability, with the stair ascent presenting the best rates. On the other hand, onset has proved to be inconsistent in all measures. Our findings suggest that stair ascent is more reliable than stair descent to evaluate subjects with PFPS in the most cases.

The Patella Pro study - effect of a knee brace on patellofemoral pain syndrome: design of a randomized clinical trial (DRKS-ID:DRKS00003291)

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a frequent cause of anterior knee pain predominantly affecting young female patients who do not have significant chondral damage. Development of PFPS is probably multifactorial, involving various knee, hip, and foot kinematic factors. Biomechanical studies have described patellar maltracking and dynamic valgus (functional malalignment) in patients with patellofemoral pain syndrome. The literature provides evidence for short-term use of nonsteroidal anti-inflammatory drugs; short-term medially directed taping; and exercise programs focusing on the lower extremity, hip, and trunk muscles. Evidence supporting the use of patellar braces is limited because previous studies have been low quality. The aim of this article is to publish the design of a prospective randomized trial that examines the outcomes of patients with PFPS after treatment with a new patellar brace (Patella Pro) that applies medially directed force on the patella.

METHODS/DESIGN

For this multicenter trial, 156 patients (adolescents and young adults) with PFPS were recruited from orthopedic practices and orthopedic hospitals and randomly allocated to 3 months of supervised physiotherapy in combination with the Patella Pro brace or supervised physiotherapy alone. The primary outcome measures are pain (numerical analog scale); knee function (Kujala score and Knee Injury and Osteoarthritis Outcome Score); and self-reported perception of recovery at baseline, 6 weeks, 3 months, and 1 year.

DISCUSSION

Only limited evidence for the use of a patellar brace for the treatment of PFPS exists in the literature. Disputable evidence for the use of orthoses for PFPS patients has been presented in one meta-analysis, in which only one of three studies found the effect of a medially directed patellar brace to be significant. Because of these low-quality studies, the authors concluded that this evidence should be regarded as limited, and we feel there is a need for further well-designed studies to evaluate the effect of patellar bracing on PFPS-related pain. The Patella Pro study is a prospective randomized trial in which supervised physiotherapy in combination with a patellar brace is compared with supervised physiotherapy alone. This trial started in April 2012 and finished in October 2013.

TRIAL REGISTRATION

DRKS-ID:DRKS00003291, January 3rd, 2012.

Patellofemoral pain syndrome

The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes.

LEVEL OF EVIDENCE

V.

The non-operative treatment of anterior knee pain

Anterior knee pain is a common presenting complaint, and in many cases no identifiable cause can be found. In these circumstances it is commonly known as anterior knee pain syndrome or patellofemoral pain syndrome. The management for this condition is most commonly non-operative. Treatment strategies include physiotherapy, pharmacotherapy, orthoses and combinations of the above. There are many described methods in the literature with a wide spectrum of outcomes, which in itself is testimony to the lack of any generally accepted gold standard of care for these patients. It is thus unclear to the health care professional treating these patients which is the best treatment to offer. In this review we aim to summarise historical and most up to date literature on the subject and in so doing allow the health care professional pick whichever treatment strategy they feel most beneficial and also provide a guide for appropriate patient education.

Patellofemoral pain: proximal, distal, and local factors, 2nd International Research Retreat

Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.