Rest-activity daily rhythm and physical activity levels after hip and knee joint replacement: the role of actigraphy in orthopedic clinical practice.

Elective hip and knee joint replacement for osteoarthritis are cost-effective surgical procedures requiring specific rehabilitation programs. Actigraphy is widely used in both research and clinical practice to study activity patterns with great accuracy and validity but it has never been utilized in orthopedic patients. Therefore, the aim of this study was to objectively assess, through actigraphy, physical activity (PA) levels and rest-activity daily rhythm (RAR) in patients undergoing hip or knee joint replacement and hospitalized for ten days after surgery. Twenty subjects (11 males and 9 females; age: 62.68 ± 10.39 years old; BMI: 29.03 ± 3.92 kg/m2) wore the Actiwatch 2 actigraph (Philips Respironics, Portland, OR) to record both PA levels and RAR for 11 consecutive days and data on subjective scores of pain, by a visual analog scale (VAS), and functional and clinical scores were collected. The following time-points were considered for the statistical analysis: pre-surgery (PRE), the first (POST1), the fourth (POST4) and the tenth (POST10) day after surgery. RAR were processed with the population mean cosinor to describe the rhythm's characteristics (acrophase, amplitude and MESOR) while data on actigraphy-based PA, VAS, and functional clinical scores were compared among PRE, POST1, POST4 and POST 10 with the RM-ANOVA or the non-parametric Friedman test. The day after surgery the subjects had a flattened RAR compared to the other conditions: lower values were detected in POST1 compared to both PRE, POST4 and POST10 for MESOR (p < .0001; η2p = .71, large) and amplitude (p < .0001; η2p = .63, large) while RAR's acrophase (p < .0001; η2p = .61, large) was delayed in PRE (16:45) compared to POST1 (12:42), POST4 (14:38), and POST10 (14:38). PA levels were significantly lower at POST 1 (76.7 ± 33.4) compared to PRE (192.3 ± 91.5; p < .0001 and ES: 1.68, large), POST4 (137.9 ± 45.9; p < .0001 and ES: 1.54, large), and POST10 (131.2 ± 54.3; p < .0001 and ES: 1.21, large) whereas VAS and functional clinical values significantly improved at POST10. Hip and knee joint replacement negatively influenced RAR and PA the first day after surgery but a progressive improvement in the circadian pattern of rest-activity cycle, PA levels, VAS and functional ability was recorded from POST4 to POST10. Actigraphy has the ability to collect real-life data without interfering with clinical practice and give clinicians a new measure of performance that is currently not available. This tool could allow to identify patients with disrupted circadian rhythm and reduced PA in the peri-operative period in orthopedic surgery, and timely intervene on these subjects with personalized rehabilitative intervention.

Motor imagery training speeds up gait recovery and decreases the risk of falls in patients submitted to total knee arthroplasty.

With Motor imagery (MI), movements are mentally rehearsed without overt actions; this procedure has been adopted in motor rehabilitation, primarily in brain-damaged patients. Here we rather tested the clinical potentials of MI in purely orthopaedic patients who, by definition, should maximally benefit of mental exercises because of their intact brain. To this end we studied the recovery of gait after total knee arthroplasty and evaluated whether MI combined with physiotherapy could speed up the recovery of gait and even limit the occurrence of future falls. We studied 48 patients at the beginning and by the end of the post-surgery residential rehabilitation program: half of them completed a specific MI training supported by computerized visual stimulation (experimental group); the other half performed a non-motoric cognitive training (control group). All patients also had standard physiotherapy. By the end of the rehabilitation, the experimental group showed a better recovery of gait and active knee flexion-extension movements, and less pain. The number of falls or near falls after surgery was significantly lower in the experimental group. These results show that MI can improve gait abilities and limit future falls in orthopaedic patients, without collateral risks and with limited costs.

The Importance of Cognitive Executive Functions in Gait Recovery After Total Hip Arthroplasty.

OBJECTIVE: To determine the influence of cognitive functioning on gait recovery after total hip arthroplasty. DESIGN: Prospective cohort study. SETTING: Rehabilitation hospital. PARTICIPANTS: Patients (N=40) who underwent a total hip arthroplasty, with normal cognitive functioning and without any other relevant medical condition, were recruited and studied before surgery and at the beginning and the end of the rehabilitation program. MAIN OUTCOME MEASURES: Gait speed (10-Meter Walk Test [10MWT]) and gait functional mobility (Timed Up and Go [TUG] test), measured at the time of discharge from the rehabilitation unit, were the primary outcomes. The candidate predictors were the cognitive and psychological variables collected in the presurgery phase, together with other potentially informative measures such as age, education, perceived pain, body mass index, presurgical gait speed and functional mobility. RESULTS: Our results suggest the existence of a direct relationship between cognitive functioning, with specific reference to high-level frontal executive functions, and the postoperative gait progress: the better the cognitive functioning in the preoperative phase, the better the course of recovery in terms of gait speed and functional mobility. In particular, the performance of the Frontal Assessment Battery test, together with age, perceived pain. Presurgical gait speed and functional mobility, was the best predictor of recovery of walking measured by 10MWT and TUG. CONCLUSIONS: The present study highlights the importance of cognitive functioning, together with clinical and demographic features, in the postsurgical recovery of walking, even in the absence of cognitive decline. In particular, these data show the crucial role of higher-order cognitive processes, such as executive functions, involved in the formulation of motor plans and their integration with proprioceptive and visual cues.

How aging affects the premotor control of lower limb movements in simulated gait.

Gait control becomes more demanding in healthy older adults, yet what cognitive or motor process leads to this age-related change is unknown. The present study aimed to investigate whether it might depend on specific decay in the quality of gait motor representation and/or a more general reduction in the efficiency of lower limb motor control. Younger and older healthy participants performed in fMRI a virtual walking paradigm that combines motor imagery (MI) of walking and standing on the spot with the presence (Dynamic Motor Imagery condition, DMI) or absence (pure MI condition) of overtly executed ankle dorsiflexion. Gait imagery was aided by the concomitant observation of moving videos simulating a stroll in the park from a first-person perspective. Behaviorally, older participants showed no sign of evident depletion in the quality of gait motor representations, and absence of between-group differences in the neural correlates of MI. However, while younger participants showed increased frontoparietal activity during DMI, older participants displayed stronger activation of premotor areas when controlling the pure execution of ankle dorsiflexion, regardless of the imagery task. These data suggest that reduced automaticity of lower limb motor control in healthy older subjects leads to the recruitment of additional premotor resources even in the absence of basic gait functional disabilities.

A functional limitation to the lower limbs affects the neural bases of motor imagery of gait.

Studies on athletes or neurological patients with motor disorders have shown a close link between motor experience and motor imagery skills. Here we evaluated whether a functional limitation due to a musculoskeletal disorder has an impact on the ability to mentally rehearse the motor patterns of walking, an overlearned and highly automatic behaviour. We assessed the behavioural performance (measured through mental chronometry tasks) and the neural signatures of motor imagery of gait in patients with chronic knee arthrosis and in age-matched, healthy controls. During fMRI, participants observed (i) stationary or (ii) moving videos of a path in a park shown in the first-person perspective: they were asked to imagine themselves (i) standing on or (ii) walking along the path, as if the camera were "their own eyes" (gait imagery (GI) task). In half of the trials, participants performed a dynamic gait imagery (DGI) task by combining foot movements with GI. Behavioural tests revealed a lower degree of isochrony between imagined and performed walking in the patients, indicating impairment in the ability to mentally rehearse gait motor patterns. Moreover, fMRI showed widespread hypoactivation during GI in motor planning (premotor and parietal) brain regions, the brainstem, and the cerebellum. Crucially, the performance of DGI had a modulatory effect on the patients and enhanced activation of the posterior parietal, brainstem, and cerebellar regions that the healthy controls recruited during the GI task. These findings show that functional limitations of peripheral origin may impact on gait motor representations, providing a rationale for cognitive rehabilitation protocols in patients with gait disorders of orthopaedic nature. The DGI task may be a suitable tool in this respect.

Mental steps: Differential activation of internal pacemakers in motor imagery and in mental imitation of gait.

Gait imagery and gait observation can boost the recovery of locomotion dysfunctions; yet, a neurologically justified rationale for their clinical application is lacking as much as a direct comparison of their neural correlates. Using functional magnetic resonance imaging, we measured the neural correlates of explicit motor imagery of gait during observation of in-motion videos shot in a park with a steady cam (Virtual Walking task). In a 2 × 2 factorial design, we assessed the modulatory effect of gait observation and of foot movement execution on the neural correlates of the Virtual Walking task: in half of the trials, the participants were asked to mentally imitate a human model shown while walking along the same route (mental imitation condition); moreover, for half of all the trials, the participants also performed rhythmic ankle dorsiflexion as a proxy for stepping movements. We found that, beyond the areas associated with the execution of lower limb movements (the paracentral lobule, the supplementary motor area, and the cerebellum), gait imagery also recruited dorsal premotor and posterior parietal areas known to contribute to the adaptation of walking patterns to environmental cues. When compared with mental imitation, motor imagery recruited a more extensive network, including a brainstem area compatible with the human mesencephalic locomotor region (MLR). Reduced activation of the MLR in mental imitation indicates that this more visually guided task poses less demand on subcortical structures crucial for internally generated gait patterns. This finding may explain why patients with subcortical degeneration benefit from rehabilitation protocols based on gait observation. Hum Brain Mapp 38:5195-5216, 2017. © 2017 Wiley Periodicals, Inc.

Length of stay and short-term functional outcomes after total knee arthroplasty: Can we predict them?

BACKGROUND: To identify variables influencing length of stay (LOS) and short-term functional outcome in patients undergoing total knee arthroplasty (TKA). A secondary aim was to verify the effect of the same variables on blood management and the rate of postoperative infection. METHOD: We retrospectively reviewed 353 patients, 258 females and 85 males, who underwent primary TKA in a single specialist orthopaedic centre. Anamnestic and anthropometric data and the Modified Barthel Index Score (MBI) at admission were recorded, and entered as covariates in four longitudinal regression models, separately carried out for female and male groups. The regression outcomes were LOS, MBI change, rate of infection and blood transfusion. Statistical significance was set at p<0.05. RESULTS: Mean LOS was 15.93±4.97days for females and 13.41±3.63days for males. Mean MBI improvement was statistically significant in both groups. 46.3% females and 29.4% males needed at least one blood transfusion, while infections complicated the hospitalization in 14.6% and 4.7% cases respectively. Among females, older age was predictive for a longer LOS and poorer post-operative MBI improvement. Lower MBI at admission was related to a longer LOS and to a higher risk of post-surgical infections in the female group, but to a better improvement of functional outcome in both groups. A higher rate of blood transfusion postoperatively was associated to lower pre-surgical haemoglobin levels and, for females, to older age and lower BMI. CONCLUSION: An accurate characterization of TKA candidates might help in reducing LOS and in achieving a better early functional outcome.