It is largely unknown how the CNS regulates multiple muscle systems in the presence of pain. This study used muscle synergy analysis to investigate multiple forearm muscles in individuals with chronic elbow pain during the development of grip force. Eleven individuals with chronic elbow pain and 11 healthy age-matched control subjects developed grip force to 15% and 30% of maximum voluntary contraction (MVC). Surface electromyography was obtained from six forearm muscles during force development before nonnegative matrix factorization was performed. The relationship between muscle synergies and standard clinical tests of elbow pain were examined by linear regression. During grip force development to 15% MVC the pain group had a lower number of forearm muscle synergies, increased similarity in spatial activation patterns, increased cocontraction of forearm flexors, and a greater magnitude of muscle weightings across the forearm when performing the task. During the 30% MVC grip the numbers of muscle synergies were the same for both groups; however, the pain group had lower activation and reduced variability in the timing of peak activation. The timing of peak activation was delayed in the pain group regardless of the task, and performing the grip in different wrist postures did not affect muscle synergy characteristics in either group. Although localized pain causes direct dysfunction of an affected muscle, this study provides evidence that the timing and amplitude of agonist and antagonist muscle activity are also affected with chronic pain. Muscle activation patterns of individuals with chronic elbow pain are simplified compared with healthy individuals. This is apparent as individuals with pain exhibit fewer forearm muscle synergies, and increased similarity of activation patterns between forearm muscles, when performing pain-free isometric gripping. As such, even during pain-free tasks it is possible to observe changes in motor control in people with chronic pain.

ObjectiveTo investigate the relationship between tendon structural changes determined by static ultrasound images (US) and sensory changes using quantitative sensory testing (QST), and clinical measures in lateral epicondylalgia.Materials and methodsBoth elbows of 66 adult participants with a clinical diagnosis of lateral epicondylalgia were investigated. Using a standardised ultrasound image rating scale, common extensor hypoechogenicity, heterogenicity, neovascularity, and bony abnormalities at the enthesis were scored, and tendon thickness (longitudinal and transverse plane) was measured by a trained assessor. Sensory measures of pressure, heat and cold pain thresholds and vibration detection threshold were recorded. Pain and function were assessed using the patient-rated tennis elbow (PRTEE), pain-free grip strength, pain visual analog scale (PVAS) and quality of life (EuroQoL EQ -5D). Univariate and multivariate linear regression analyses were used to explore the association between tendon structural, sensory and clinical variables which were adjusted for age, gender and duration of symptoms.ResultsA negative correlation was identified between the presence of neovascularity and cold pain threshold (P = 0.015). Multiple regression analyses revealed that a combination of female gender (P = 0.044) and transverse tendon thickness (P = 0.010) were significantly associated with vibration detection threshold in affected elbows, while gender (P = 0.012) and total ultrasound scale score (P = 0.024) were significantly associated with heat pain threshold and vibration detection threshold in unaffected elbows. Heat pain threshold and gender were significantly associated with pain and disability (PRTEE; P < 0.001), and pain-free grip strength (P < 0.001) respectively, in the affected elbows.ConclusionGenerally, structural and sensory measures were weakly correlated. However, neovascularity and transverse tendon thickness may be related to sensory system changes in LE.

Despite suggestions that tourniquet inflation during total knee replacement reduces bleeding and hence improves cement penetration, no studies exist supporting this widely held belief. In this single-blinded, single-surgeon, randomized controlled trial, the tourniquet inflation during cementation group ( n = 20) did not have greater tibial cement penetration compared to a no tourniquet group ( n = 20). No statistically significant differences in semiautomatic digitally measured average and central radiographic tibial plateau penetration values were observed between the two groups ( p = 0.93; p = 0.84). Tourniquet inflation during cementation does not appear to improve tibial cementation penetration.

Background Lateral epicondylalgia (tennis elbow) is a common, debilitating and often treatment-resistant condition. Two treatments thought to address the pathology of lateral epicondylalgia are hypertonic glucose plus lignocaine injections (prolotherapy) and a physiotherapist guided manual therapy/exercise program (physiotherapy). This trial aimed to compare the short- and long-term clinical effectiveness, cost effectiveness, and safety of prolotherapy used singly and in combination with physiotherapy. Methods Using a single-blinded randomised clinical trial design, 120 participants with lateral epicondylalgia of at least six weeks’ duration were randomly assigned to prolotherapy (4 sessions, monthly intervals), physiotherapy (weekly for 4 sessions) or combined (prolotherapy+physiotherapy). The Patient-Rated Tennis Elbow Evaluation (PRTEE) and participant global impression of change scores were assessed by blinded evaluators at baseline, 6, 12, 26 and 52 weeks. Success rate was defined as the percentage of participants indicating elbow condition was either 'much improved' or 'completely recovered.’ Analysis was by intention-to-treat. Results 88% completed the 12-month assessment. At 52 weeks, there were substantial, significant improvements compared with baseline status for all outcomes and groups, but no significant differences between groups. The physiotherapy group exhibited greater reductions in PRTEE at 12 weeks than the prolotherapy group (p = 0.014). Conclusion There were no significant differences amongst the Physiotherapy, Prolotherapy and Combined groups in PRTEE and global impression of change measures over the course of the 12-month trial.

BackgroundLateral epicondylalgia (tennis elbow) is a common, debilitating and often treatment-resistant condition. Two treatments thought to address the pathology of lateral epicondylalgia are hypertonic glucose plus lignocaine injections (prolotherapy) and a physiotherapist guided manual therapy/exercise program (physiotherapy). This trial aimed to compare the short- and long-term clinical effectiveness, cost effectiveness, and safety of prolotherapy used singly and in combination with physiotherapy.MethodsUsing a single-blinded randomised clinical trial design, 120 participants with lateral epicondylalgia of at least 6 weeks’ duration were randomly assigned to prolotherapy (4 sessions, monthly intervals), physiotherapy (weekly for 4 sessions) or combined (prolotherapy+physiotherapy). The Patient-Rated Tennis Elbow Evaluation (PRTEE) and participant global impression of change scores were assessed by blinded evaluators at baseline, 6, 12, 26 and 52 weeks. Success rate was defined as the percentage of participants indicating elbow condition was either ‘much improved’ or ‘completely recovered.’ Analysis was by intention-to-treat.ResultsEighty-eight percent completed the 12-month assessment. At 52 weeks, there were substantial, significant improvements compared with baseline status for all outcomes and groups, but no significant differences between groups. The physiotherapy group exhibited greater reductions in PRTEE at 12 weeks than the prolotherapy group (p = 0.014).ConclusionThere were no significant differences amongst the Physiotherapy, Prolotherapy and Combined groups in PRTEE and global impression of change measures over the course of the 12-month trial.Trial registrationACTRN12612000993897.