Maximum knee extension velocity without external load is a stronger determinant of gait function than quadriceps strength in the early postoperative period following total knee arthroplasty.

OBJECTIVE: Quadriceps weakness is considered the primary determinant of gait function after total knee arthroplasty (TKA). However, many patients have shown a gap in improvement trends between gait function and quadriceps strength in clinical situations. Factors other than quadriceps strength in the recovery of gait function after TKA may be essential factors. Because muscle power is a more influential determinant of gait function than muscle strength, the maximum knee extension velocity without external load may be a critical parameter of gait function in patients with TKA. This study aimed to identify the importance of knee extension velocity in determining the gait function early after TKA by comparing the quadriceps strength. METHODS: This prospective observational study was conducted in four acute care hospitals. Patients scheduled for unilateral TKA were recruited (n = 186; age, 75.9 ± 6.6 years; 43 males and 143 females). Knee extension velocity was defined as the angular velocity of knee extension without external load as quickly as possible in a seated position. Bilateral knee function (knee extension velocity and quadriceps strength), lateral knee function (pain and range of motion), and gait function (gait speed and Timed Up and Go test (TUG)) were evaluated before and at 2 and 3 weeks after TKA. RESULTS: Both bilateral knee extension velocities and bilateral quadriceps strengths were significantly correlated with gait function. The knee extension velocity on the operation side was the strongest predictor of gait function at all time points in multiple regression analysis. CONCLUSION: These findings identified knee extension velocity on the operation side to be a more influential determinant of gait function than impairments in quadriceps strength. Therefore, training that focuses on knee extension velocity may be recommended as part of the rehabilitation program in the early postoperative period following TKA. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR) UMIN000020036.

Analyzing the characteristics of rising from the bed in patients having undergone total hip arthroplasty immediately after surgery.

BACKGROUND: Immediately after patients undergo total hip arthroplasty (THA), they are often coached through the process of rising from the bed to prevent dislocation. However, motion analysis of this process, which can guide coaching methods, has not been conducted. The purpose of this study was to clarify whether there is a difference in hip joint angle, rise time, pain, and difficulty based on the method of rising from the bed in postoperative patients, immediately after THA. METHODS: Twenty patients who underwent THA were enrolled in this study. Seven days after surgery, 3-D motion analysis was performed while subjects rose from the bed using six different methods that include rising from the bed using either the affected or non-affected side either with or without assistance. Hip joint angle, rise time, pain, and difficulty were evaluated. RESULTS: In all six methods, the maximal hip joint angle of the affected side was in the safe range. The maximal hip adduction angle and adduction angle at maximum flexion of the affected side were significantly lower in patients who rose from the bed using their affected side than in those who rose using their non-affected side. There were no differences in maximal hip flexion angle, internal rotation angle, internal rotation angle at maximum flexion of the affected side, rise time, pain, or difficulty regardless of the direction of rising from the bed or the use of assistance. SIGNIFICANCE: Coaching patients to rise from the bed is better performed when using the most optimal method that takes into consideration the movement direction and patient's individuality.

Electrical stimulation ventilatory feedback facilitates maintenance of a prolonged expiration pattern during exercise: A proof-of-concept study in healthy adults.

This study aimed at verifying the safety and effects of electrical stimulation ventilatory feedback (ESVF) to provide feedback during expiration, which may assist with breathing control in patients with chronic obstructive pulmonary disease (COPD). Because this is a new therapy, we examined the feasibility of the therapy in healthy adults. The 23 healthy adult participants were randomized into two groups: a stimulation group that received ESVF and a placebo group with the ESVF device attached, but not activated. Sensory stimulation was provided at a frequency of 20 Hz and pulse duration of 200 µs. During breathing training, participants practiced a prolonged expiration pattern and were instructed to maintain the breathing pattern during exercise. A variety of parameters such as respiratory time from the gas analyzer monitor and quantitative load were measured during lower-extremity cycle ergometer exercise. The primary outcome was the expiratory to inspiratory time ratio, which was significantly higher in the stimulation group than in the placebo group, both during and after exercise. No side effects were reported during the use of electrical stimulation. Therefore, ESVF is safe and facilitates maintenance of a prolonged expiration pattern during and after exercise.

Electrically stimulated ventilation feedback improves the ventilation pattern in patients with COPD.

[Purpose] We aimed to determine the effects of ventilation feedback using electrical stimulation on ventilation pattern during exercise in patients with chronic obstructive pulmonary disease (COPD), and develop new rehabilitation methods. [Subjects] This randomized double-blind placebo-controlled trial included 24 patients with COPD. [Methods] Phasic electrical stimulation during expiration (PESE) or a placebo was given to all the cases. Minute ventilation (VE), tidal volume (TV), respiratory rate (RR), expiratory time (Te), total respiratory time (Ttot), dead-space gas volume to tidal gas volume (VD/VT), oxygen uptake (VO2), carbon dioxide output (VCO2), Borg scale (Borg), and percutaneous oxygen saturation (SpO2) during rest and exercise were assessed. [Results] The placebo group showed no obvious change in ventilation measurements at rest or during exercise. However, in the PESE group, TV, Te, and Ttot significantly increased, while RR and VD/VT significantly decreased during exercise compared with the baseline measurements. Borg scores, SpO2, VO2, or VCO2 did not differ significantly. [Conclusion] PESE improves the ventilation pattern during rest and exercise. Furthermore, PESE does not increase VO2, which may indicate an increased workload. Biofeedback may contribute to PESE effects. Stimulation applied during expiration may evoke sensations increasing prolonged expiration awareness, facilitating prolongation.