Proprioceptive deficit after total elbow arthroplasty: an observational study.

BACKGROUND: During total elbow arthroplasty (TEA), most of the joint capsule is removed, including many mechanoreceptors important for proprioception, which potentially limits the patient's postoperative functional recovery. We quantified proprioceptive loss by measuring the threshold to detection of passive motion (TTDPM) in patients after unilateral TEA compared with the contralateral side. METHODS: A continuous passive motion device moving the elbow at 0.5°/s was used to evaluate TTDPM in 8 patients (mean ± standard deviation age, 69.1 ± 9.93 years) at least 1 year after unilateral semiconstricted linked TEA for a range of diagnoses. Elbow function after TEA was assessed using the Mayo Elbow Performance Scale. RESULTS: Postsurgical Mayo scores revealed 4 excellent results, 2 good, and 2 poor. The TTDPM in the elbows undergoing arthroplasty was still significantly higher compared with the contralateral elbow at 4.2° (15.6 ± 6.9 seconds vs. 7.2 ± 2.6 seconds; D = 3.23, P = .01) equivalent to 8.4 seconds. CONCLUSIONS: Patients who have had severe joint disease requiring semiconstrained TEA have long-term proprioception deficits. A more conservative technique that maximally preserves insertions and soft tissues, might minimize upper limb proprioceptive deficit.

Effect of cooling foot sole skin receptors on achilles tendon reflex.

INTRODUCTION: This study investigated whether a controlled reduction of foot sole temperature affects the Achilles tendon stretch reflex and plantar flexion. Methods Five stretch reflexes in 52 healthy subjects were evoked by Achilles tendon taps. Short latency responses of 3 muscles of the lower limb and maximal force of plantar flexion were analyzed. Foot sole hypothermia was induced by a thermal platform at various foot temperature conditions: Stage I (25°C), Stage II (12°C), Stage IIIa (0°C), and Stage IIIb (0°C). Results Reduction of plantar cutaneous inputs resulted in a decrease in amplitude of medial gastrocnemius and soleus as well as delays in time to maximal force of plantar flexion. Medial gastrocnemius, lateral gastrocnemius, and soleus were affected differently by induced cooling. No inhibition effects in reflexes were observed at 12°C. Conclusions The results suggest that input on the plantar foot sole participates complementarily in the Achilles stretch reflex Muscle Nerve, 2015. Muscle Nerve 53: 965-971, 2016.

Children with ADHD show no deficits in plantar foot sensitivity and static balance compared to healthy controls.

The goal of this study was to investigate plantar foot sensitivity and balance control of ADHD (n=21) impaired children compared to age-matched healthy controls (n=25). Thresholds were measured at 200 Hz at three anatomical locations of the plantar foot area of both feet (hallux, first metatarsal head (METI) and heel). Body balance was quantified using the length, area and velocity described by the center of pressure (COP) during two-legged as well as one-legged stand (right and left legs). The comparison of vibration thresholds showed no differences between ADHD and healthy children at all anatomical locations of both feet. Whereas COP excursion and area were significantly lower in ADHD subjects compared to the healthy controls during two-legged stand, no differences were found in those variables when balancing on one leg. No differences in COP velocity between ADHD and healthy children were found in any analyzed conditions. The results indicate that the unusual and simple test situation may have increased the perception of vibration stimuli by the ADHD children. Furthermore, ADHD subjects seem to be less variable when performing simple tasks than healthy controls.

Whole body vibration training reduces plantar foot sensitivity but improves balance control of healthy subjects.

The goal of this study was to investigate the effects of short-time whole body vibration (WBV) training on foot vibration sensitivity of healthy subjects. Furthermore, the effects of WBV on a balance task (one-leg stand) were also evaluated. 30 young healthy subjects participated in the study. Vibration perception thresholds and balance were measured prior and after a single session of a 4-min WBV training (27Hz, 2mm horizontal amplitude). Thresholds were measured at 200Hz at three anatomical locations of the plantar foot area (first and fifth metatarsal heads and heel). Body balance was quantified using the length as well as the area described by the center of pressure (COP) at quiet, one-leg standing. Whereas vibration thresholds significantly increased after WBV training at all measured locations, there was a significant decrease in the balance related parameters after WBV exercise. The results indicate that the above-threshold, sinusoidal vibration used during WBV training is not an adequate strategy to stimulate/improve vibration sensitivity. The improvements seen in balance after WBV are likely to have neuromuscular mechanisms as their main component rather than increased foot sensitivity.

Short-time lower leg ischemia reduces plantar foot sensitivity.

The aim of this study was to investigate the effects of short-time blood flow occlusion on plantar foot vibration sensitivity of healthy young adults. 39 subjects (20 female; 19 male) participated in the study. Blood flow reduction was evoked with a pneumatic tourniquet, placed about 10 cm above the popliteus cavity. Vibration thresholds (200 Hz) were measured at three anatomical locations of the plantar foot (heel, first metatarsal head and hallux) in three different cuff pressure conditions: baseline (0 mmHg), low (50 mmHg) and high (150 mmHg). Each pressure condition was held for 4 min prior to vibration threshold measurements. No reperfusion time was allowed between conditions. The results show a significant increase in vibration thresholds measured at all anatomical locations in the high pressure condition (150 mmHg), whereas low pressure (50 mmHg) caused a significant threshold increase only at the hallux, compared to baseline (0 mmHg) measurements. Short-time blood flow occlusion seems to affect the afferent transmission of vibration stimuli from Vater-Pacini corpuscles, resulting in decreased plantar foot sensitivity. The present study provides an insight into initial adaptations caused by reduced blood flow in plantar foot sensitivity of healthy young adults.

Foot sole skin temperature affects plantar foot sensitivity.

OBJECTIVE: Factors like age and polyneuropathic diseases are known to influence foot sensitivity and are considered when applying quantitative sensory testing. However, the effects of temperature on foot sensitivity are controversial. Therefore, the aim of this study was to investigate the influence of different foot sole temperature on vibration sensitivity of healthy subjects. METHODS: Forty healthy subjects (20 male, 20 female) were analyzed. Vibration thresholds were measured at three anatomical locations (Heel, 1st Metatarsal Head and Hallux) of both feet at 200Hz. Thresholds were measured at initial baseline temperature and after cooling/warming of the foot skin 5-6 degrees C. Comparisons between baseline and cooled/warmed thresholds as well as between genders were performed. RESULTS: There were no significant differences in vibration thresholds when comparing men and women. Thresholds were significantly higher after skin cooling for at all anatomical locations. After skin warming, thresholds were significantly lower at all measured anatomical locations. CONCLUSIONS: Small temperature changes significantly influence vibration sensitivity of healthy subjects and should be controlled during collection of foot sensitivity data. SIGNIFICANCE: The control of temperature is an important factor to enhance the quality of data acquired with quantitative sensory testing.

Effects of footwear on plantar foot sensitivity: a study with Formula 1 shoes.

The aim of this study was to investigate the influence of Formula 1 footwear on the ability of the plantar foot to detect vibration stimuli. Twenty-five male subjects participated in the study. Five foot/shoe conditions were analysed (barefoot and four shoe conditions). Vibration thresholds were measured at three anatomical locations of the plantar foot (heel, first metatarsal head and hallux) at two frequencies (30 and 200 Hz). The results show a frequency-dependent influence of footwear on foot sensitivity. The comparison between barefoot and shod conditions showed lower thresholds (P < 0.01) for the barefoot condition at 30 Hz, whereas lower thresholds (P < 0.01) were found for all shoe conditions at 200 Hz compared to barefoot. Lower thresholds (P < 0.01) were measured at 200 Hz in comparison to 30 Hz in all experimental conditions. The shoe outsole material seems to facilitate the transmission of high-frequent vibration stimuli to the skin, resulting in better vibration sensitivity at 200 Hz when wearing Formula 1 shoes compared to barefoot.