Mass perturbation of a body segment: 1. Effects on segment dynamics

Investigators often use mass perturbation of body segments as an experimental paradigm to study movement coordination. To analyze the effect of mass perturbation on small-amplitude oscillations, the authors linearize the equation of motion of a single segment moving in a vertical plane and derive the effect of added mass on the undamped eigenfrequency, the relative damping, and the low-frequency control gain of the segment. Mass addition results in a decrease in both the relative damping and the low-frequency control gain; the undamped eigenfrequency increases for mass addition between the pivot point and

Weighing weight : effect of below-knee prosthetic inertial properties on gait

In this thesis, the influence of prosthetic inertial properties (mass, mass distribution and moment of inertia) on the gait of transtibial amputation (TTA) subjects is studied. Chapter 1 introduces the present ideas on prosthetic mass. It describes that the general design effort has always been, and still is, to reduce prosthetic mass. However, as far as we know, lightweight design has never been advocated in the present literature. The Chapter introduces the opposite view, found in a relatively large body of literature, that lightweight design might not be beneficial for prosthetic gait. The aim of this thesis, therefore, is to determine the optimal inertial properties of the prosthetic leg

Item reduction of the patient-rated wrist evaluation using decision tree modelling

Background: The aim of this study is to assess the viability of a decision tree version of an often used questionnaire to measure wrist pain and disability, the Patient Rated Wrist Evaluation. Methods: Patient Rated Wrist Evaluation scores were collected from a cohort of 10394 patients who are part of a routine outcome measurement system. A decision tree version of the Patient Rated Wrist Evaluation (PRWE) was created. The intraclass correlation was used to evaluate the inter-version reliability between the original PRWE and the decision tree version. Results: The decision tree reduced the number of questions from 5 to 3 for the pain subscale, and from 10 to 3 for the disability subscale. The intraclass correlation between the original PRWE and the decision tree version was 0.97. The mean difference between the Patient Rated Wrist Evaluation and the decision tree Patient Rated Wrist Evaluation total sumscore was 0.35 (95% CI 9.92–10.62). Conclusions: We found that the decision tree was successful at reducing the items of the Patient Rated Wrist Evaluation from fifteen to only six questions with very high similarity to the scores of the full questionnaire

The difference between actual and prescribed weight bearing of total hip patients with a trochanteric osteotomy: long-term vertical force measurements inside and outside the hospital

OBJECTIVE: To determine whether patients load the operated leg at a prescribed weight-bearing target load during postoperative recovery. DESIGN: A descriptive prospective study. SETTING: Orthopedic clinic and patients' homes. PARTICIPANTS: Fifty patients who had undergone total hip arthroplasty (THA) with trochanteric osteotomy. INTERVENTION: Patients were verbally instructed by a physical therapist to perform partial weight bearing at a 10% body weight (BW) target load (n=33) or at a 50% BW target load (n=17). MAIN OUTCOME MEASURES: Mean peak load (%BW) and percentage of patients and mean percentage of steps below, equal to, and above the target load. Weight bearing was measured when patients walked with (condition 1) and without (condition 2) a physical therapist in the hospital and walked at home (condition 3). RESULTS: The mean peak load was significantly higher than the target in the 10% BW group for all 3 conditions (condition 1, 19.2% BW; condition 2, 20.0% BW; condition 3, 26.8% BW). In the 50% BW group, the mean peak load was significantly lower than the target in conditions 1 (28.1% BW) and 2 (32.5% BW). No significant difference in weight bearing was found when walking with or without a physical therapist (change in 10% BW, -0.1% BW; change in 50% BW, -3.17% BW). At home, the mean peak load was significantly larger compared with walking without a physical therapist in the hospital (change in 10% BW, -7.0% BW; change in 50% BW, -11.5% BW). CONCLUSIONS: Partial weight bearing at a specific target load was not achieved by patients with a THA when given verbal instructions. Especially when using a low target load and when walking at home with no supervision of a physical therapist, patients loaded the operated leg higher and more frequently above the target load. Other training methods (eg, biofeedback) have to be evaluated to use as training tools for partial weight bearing at specific target loads

Stronger relation between impairment and manual capacity in the non-dominant hand than the dominant hand in congenital hand differences; Implications for surgical and therapeutic interventions

Objectives To evaluate manual activity capacity (i.e. activity capacity to perform hand activities) and its relation with body functions of the hand and forearm in children with congenital hand differences (CHD) Methods We assessed 10-14 year-old children with CHD (N = 106) using a functional handgrips test. Measurements of body functions included joint mobility and muscle strength. Patient characteristics were hand dominance and severity. Results We found a stronger relation between body functions and manual activity capacity in non-dominant hands than dominant hands. Dominant hands scored significantly higher on manual activity capacity than nondominant hands that were similarly impaired at body functions level. Severity of the CHD and body functions had only small effects on manual activity capacity. Conclusion The relation between body functions and manual activity capacity is stronger in non-dominant hands than dominant hands, indicating that improvement in body functions lead to larger changes in manual activity capacity in the non-dominant hand. This may suggest that in bilaterally-affected children surgery should be done at the non-dominant hand first since this hand would benefit most from surgery-induced body functions improvement

Hand therapy or not following collagenase treatment for Dupuytren's contracture? Protocol for a randomised controlled trial

Background: Dupuytren’s contracture (DC) is a fibrotic hand condition in which one or more fingers develop progressive flexion deformities. Quality of life is diminished due to disabling limitations in performing everyday activities. For DC patients treated with collagenase, referral for subsequent hand therapy is inconsistent. It is unknown whether subsequent hand therapy is beneficial compared to no therapy. The purpose of this study is to determine whether hand therapy improves DC patients’ performance of and satisfaction with performing everyday activities one year after collagenase treatment. Methods: We will conduct a randomised controlled trial with two treatment groups (hand therapy vs. control) of DC patients who have received collagenase treatment. DC patients with contracted metacarpophalangeal joint(s) (MCPJ) (hand therapy, n = 40; control, n = 40) and those with proximal interphalangeal joint(s) (PIPJ) involvement (hand therapy, n = 40; control, n = 40) comprise two subgroups, and we will study if the treatment effect will be different between both groups (n = 160). Patients with a previous injury or treatment for DC in the treatment finger are excluded. Hand therapy includes oedema and scar management, splinting, movement exercises, and practice of everyday activities. The main outcome variable is patients’ performance of and satisfaction with performing everyday activities, as assessed with the Canadian Occupational Performance Measure. Secondary outcomes are DCspecific activity problems, as assessed with the Unité Rhumatologique des Affections de la Main scale, and active/ passive flexion/extension of treated joints and grip force using standard measuring tools, and self-reported pain level. Demographic and clinical variables, degree of scarring, cold hypersensitivity, number of occupational sickleave days are collected. Self-reported global impression of change will be used to assess patient satisfaction with change in hand function. Assessments are done pre-injection and 6 weeks, 4 months, and 1 year later. Standard univariate and multivariate statistical analyses will be used to evaluate group differences. Discussion: This study aims to assess whether hand therapy is beneficial for activity-related, biomechanical, and clinical outcomes in DC patients after collagenase treatment. The results will provide an objective basis for determining whether hand therapy should be conducted after collagenase treatment

Patient’s satisfaction beyond hand function in Dupuytren’s disease: analysis of 1106 patients

This study investigates the outcomes of 1106 patients with Dupuytren’s disease treated with limited fasciectomy or percutaneous needle fasciotomy over 16 years according to the different domains of patient-reported hand function. These patients completed the Michigan Hand Outcomes Questionnaire before and 3 months after surgery. Scores for the various outcome parameters were calculated and linear regression analyses were used to examine associations between the changes in digital extension d