Jim Richards

A comparison of knee braces during walking for the treatment of osteoarthritis of the medial compartment of the knee

In this cross-over study, we evaluated two types of knee brace commonly used in the conservative treatment of osteoarthritis of the medial compartment. Twelve patients confirmed radiologically as having unilateral osteoarthritis of the medial compartment (Larsen grade 2 to grade 4) were studied. Treatment with a simple hinged brace was compared with that using a valgus corrective brace. Knee kinematics, ground reaction forces, pain and function were assessed during walking and the Hospital for Special Surgery scores were also determined. Significant improvements in pain, function, and loading and propulsive forces were seen with the valgus brace. Treatment with a simple brace showed only significant improvements in loading forces. Our findings suggest that although both braces improved confidence and function during gait, the valgus brace showed greater benefit.

The biomechanics and clinical efficacy of footwear adapted with rocker profiles—Evidence in the literature

BACKGROUND Rocker profiles are the most commonly prescribed external therapeutic shoe modification. However, the prescription criteria for rocker profiles have historically been based on theoretical considerations with minimal scientific study and validation. OBJECTIVE Rocker profiles are used to afford pressure relief for the plantar surface of the foot, to limit the need for sagittal plane motion in the joints of the foot and to alter gait kinetics and kinematics in proximal joints. This paper reviews the literature relating to biomechanical and clinical efficacy. METHOD A literature search was undertaken in Medline, PubMed, Recal, Cochrane database and Scopus. RESULTS AND CONCLUSIONS Efficacy is demonstrated with regards to relief of forefoot plantar pressures. However, the definitive profile shape has not been demonstrated. The effectiveness of rocker-soled shoes in restricting sagittal plane motion in individual joints of the foot is unclear. Rocker profiles have minimal effect on the kinetics and kinematics of the more proximal joints of the lower limb, but more significant effects are seen at the ankle. Further research is warranted on the effects of rocker profiles on individual joints of the foot and the manner in which they effect lower limb muscle activity and gait patterns.

A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis

Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect.

The effect of three different (-135°C) whole body cryotherapy exposure durations on elite rugby league players.

Background Whole body cryotherapy (WBC) is the therapeutic application of extreme cold air for a short duration. Minimal evidence is available for determining optimal exposure time. Purpose To explore whether the length of WBC exposure induces differential changes in inflammatory markers, tissue oxygenation, skin and core temperature, thermal sensation and comfort. Method This study was a randomised cross over design with participants acting as their own control. Fourteen male professional first team super league rugby players were exposed to 1, 2, and 3 minutes of WBC at −135°C. Testing took place the day after a competitive league fixture, each exposure separated by seven days. Results No significant changes were found in the inflammatory cytokine interleukin six. Significant reductions (p<0.05) in deoxyhaemoglobin for gastrocnemius and vastus lateralis were found. In vastus lateralis significant reductions (p<0.05) in oxyhaemoglobin and tissue oxygenation index (p<0.05) were demonstrated. Significant reductions (p<0.05) in skin temperature were recorded. No significant changes were recorded in core temperature. Significant reductions (p<0.05) in thermal sensation and comfort were recorded. Conclusion Three brief exposures to WBC separated by 1 week are not sufficient to induce physiological changes in IL-6 or core temperature. There are however significant changes in tissue oxyhaemoglobin, deoxyhaemoglobin, tissue oxygenation index, skin temperature and thermal sensation. We conclude that a 2 minute WBC exposure was the optimum exposure length at temperatures of −135°C and could be applied as the basis for future studies.

Three-dimensional kinematic comparison of treadmill and overground running

The treadmill is an attractive device for the investigation of human locomotion, yet the extent to which lower limb kinematics differ from overground running remains a controversial topic. This study aimed to provide an extensive three-dimensional kinematic comparison of the lower extremities during overground and treadmill running. Twelve participants ran at 4.0 m/s ( ± 5%) in both treadmill and overground conditions. Angular kinematic parameters of the lower extremities during the stance phase were collected at 250 Hz using an eight-camera motion analysis system. Hip, knee, and ankle joint kinematics were quantified in the sagittal, coronal, and transverse planes, and contrasted using paired t-tests. Of the analysed parameters hip flexion at footstrike and ankle excursion to peak angle were found to be significantly reduced during treadmill running by 12° (p = 0.001) and 6.6° (p = 0.010), respectively. Treadmill running was found to be associated with significantly greater peak ankle eversion (by 6.3°, p = 0.006). It was concluded that the mechanics of treadmill running cannot be generalized to overground running.

A clinical study of the biomechanics of step descent using different treatment modalities for patellofemoral pain

INTRODUCTION In the previous study we have demonstrated that in healthy subjects significant changes in coronal and transverse plane mechanics can be produced by the application of a neutral patella taping technique and a patellar brace. Recently it has also been identified that patients with patellofemoral pain syndrome (PFPS) display alterations in gait in the coronal and transverse planes. OBJECTIVE This study investigated the effect of patellar bracing and taping on the three-dimensional mechanics of the knee of patellofemoral pain patients during a step descent task. METHOD Thirteen patients diagnosed with patellofemoral pain syndrome performed a slow step descent. This was conducted under three randomized conditions: (a) no intervention, (b) neutral patella taping, (c) patellofemoral bracing. A 20cm step was constructed to accommodate an AMTI force platform. Kinematic data were collected using a ten camera infra-red Oqus motion analysis system. Reflective markers were placed on the foot, shank and thigh using the Calibrated Anatomical System Technique (CAST). RESULTS The coronal plane knee range of motion was significantly reduced with taping (P=0.031) and bracing (P=0.005). The transverse plane showed a significant reduction in the knee range of motion with the brace compared to taping (P=0.032) and no treatment (P=0.046). CONCLUSION Patients suffering from patellofemoral pain syndrome demonstrated improved coronal plane and torsional control of the knee during slow step descent following the application of bracing and taping. This study further reinforces the view that coronal and transverse plane mechanics should not be overlooked when studying patellofemoral pain.

Are there three main subgroups within the patellofemoral pain population? A detailed characterisation study of 127 patients to help develop targeted intervention (TIPPs).

Background Current multimodal approaches for the management of non-specific patellofemoral pain are not optimal, however, targeted intervention for subgroups could improve patient outcomes. This study explores whether subgrouping of non-specific patellofemoral pain patients, using a series of low cost simple clinical tests, is possible. Method The exclusivity and clinical importance of potential subgroups was assessed by applying à priori test thresholds (1 SD) from seven clinical tests in a sample of adult patients with non-specific patellofemoral pain. Hierarchical clustering and latent profile analysis, were used to gain additional insights into subgroups using data from the same clinical tests. Results 130 participants were recruited, 127 had complete data: 84 (66%) female, mean age 26 years (SD 5.7) and mean body mass index 25.4 (SD 5.83), median (IQR) time between onset of pain and assessment was 24 (7–60) months. Potential subgroups defined by the à priori test thresholds were not mutually exclusive and patients frequently fell into multiple subgroups. Using hierarchical clustering and latent profile analysis three subgroups were identified using 6 of the 7 clinical tests. These subgroups were given the following nomenclature: (1) ‘strong’, (2) ‘weak and tighter’ and (3) ‘weak and pronated foot’. Conclusions We conclude that three subgroups of patellofemoral patients may exist based on the results of six clinical tests which are feasible to perform in routine clinical practice. Further research is needed to validate these findings in other data sets and, if supported by external validation, to see if targeted interventions for these subgroups improve patient outcomes.

EMG Biofeedback Based VR System for Hand Rotation and Grasping Rehabilitation

Individuals who have upper limb movement problems include people with cerebral palsy (CP) and stroke victims. Both these conditions lead to difficulties in daily activities such as reaching, grasping etc. Virtual reality (VR), which could provide a repetitive multimodal task-oriented rehabilitation environment for patients to undertake self-training in safety, is considered to be a suitable tool for medical health rehabilitation. Using electromyography (EMG) biofeedback in rehabilitation could provide patients with opportunities to improve the ability by assessing their muscle activity response and learning self-control of movement during specific training tasks. This paper presents a study on developing EMG as an important interactive tool in a VR based system for hand rotation and grasping motion rehabilitation. The input interface includes an EMG system and a real-time magnetic motion tracking system, and the output interface is a PC monitor. The developed EMG biofeedback based VR system enables the user to interact with virtual objects in real-time with multiform feedback. Ten healthy subjects participated in the preliminary task evaluation test, and the results suggest that the specified skills have improved during training. The beneficial effects of the developed system indicate the potential values for further clinical application.

A Biomechanical Investigation of A Single-Limb Squat: Implications for Lower Extremity Rehabilitation Exercise

CONTEXT Single-limb squats on a decline angle have been suggested as a rehabilitative intervention to target the knee extensors. Investigators, however, have presented very little empirical research in which they have documented the biomechanics of these exercises or have determined the optimum angle of decline used. OBJECTIVE To determine the involvement of the gastrocnemius and rectus femoris muscles and the external ankle and knee joint moments at 60 degrees of knee flexion while performing a single-limb squat at different decline angles. DESIGN Participants acted as their own controls in a repeated-measures design. PATIENTS OR OTHER PARTICIPANTS We recruited 10 participants who had no pain, injury, or neurologic disorder. INTERVENTION(S) Participants performed single-limb squats at different decline angles. MAIN OUTCOME MEASURE(S) Angle-specific knee and ankle moments were calculated at 60 degrees of knee flexion. Angle-specific electromyography (EMG) activity was calculated at 60 degrees of knee flexion. Integrated EMG also was calculated to determine the level of muscle activity over the entire squat. RESULTS An increase was seen in the knee moments (P < .05) and integrated EMG in the rectus femoris (P < .001) as the decline angle increased. A decrease was seen in the ankle moments as the decline angle increased (P = .001), but EMG activity in the gastrocnemius increased between 16 degrees and 24 degrees (P = .018). CONCLUSIONS As the decline angle increased, the knee extensor moment and EMG activity increased. As the decline angle increased, the ankle plantar-flexor moments decreased; however, an increase in the EMG activity was seen with the 24 degrees decline angle compared with the 16 degrees decline angle. This indicates that decline squats at an angle greater than 16 degrees may not reduce passive calf tension, as was suggested previously, and may provide no mechanical advantage for the knee.

Intra-individual movement variability during skill transitions: A useful marker?

Abstract Applied research suggests that athletes and coaches need to be challenged in knowing when and how much a movement should be consciously attended to. This is exacerbated when the skill is in transition between two more stable states, such as when an already well-learnt skill is being refined. Using existing theory and research, this paper highlights the potential application of movement variability as a tool to inform a coachs decision-making process when implementing a systematic approach to technical refinement. Of particular interest is the structure of co-variability between mechanical degrees-of-freedom (e.g., joints) within the movement systems entirety when undergoing a skill transition. Exemplar data from golf are presented, demonstrating the link between movement variability and mental effort as an important feature of automaticity, and thus intervention design throughout the different stages of refinement. Movement variability was shown to reduce when mental effort directed towards an individual aspect of the skill was high (target variable). The opposite pattern was apparent for variables unrelated to the technical refinement. Therefore, two related indicators, movement variability and mental effort, are offered as a basis through which the evaluation of automaticity during technical refinements may be made.