Biomedical subjects

J M Czerniecki

Publications and source records attributed to J M Czerniecki.

At least 19 recordsLinked to original sources

PubMed2006

An equinus deformity of the ankle accounts for only a small amount of the increased forefoot plantar pressure in patients with diabetes.

Patients with diabetes mellitus may develop plantar flexion contractures (equinus) which may increase forefoot pressure during walking. In order to determine the relationship between equinus and forefoot pressure, we measured forefoot pressure during walking in 27 adult diabetics with a mean age of 66.3 years (sd 7.4) and a mean duration of the condition of 13.4 years (sd 12.6) using an Emed mat. Maximum dorsiflexion of the ankle was determined using a custom device which an examiner used to apply a dorsiflexing torque of 10 Nm (sd 1) for five seconds. Simple linear regression showed that the relationship between equinus and peak forefoot pressure was significant (p < 0.0471), but that only a small portion of the variance was accounted for (R(2) = 0.149). This indicates that equinus has only a limited role in causing high forefoot pressure. Our findings suggest caution in undertaking of tendon-lengthening procedures to reduce peak forefoot plantar pressures in diabetic subjects until clearer indications are established.

Adult↗

PubMed2001

Back pain as a secondary disability in persons with lower limb amputations.

OBJECTIVE: To evaluate the frequency, duration, intensity, and interference of back pain in a sample of persons with lower limb amputations. DESIGN: Retrospective, cross-sectional survey. SETTING: Community-based survey from clinical databases. PARTICIPANTS: Participants who were 6 or more months post lower limb amputation (n = 255). INTERVENTION: An amputation pain survey that included several standardized pain measures. MAIN OUTCOME MEASURES: Frequency, duration, intensity, and interference of back pain. RESULTS: Of the participants who completed the survey (return rate, 56%), 52% reported experiencing persistent, bothersome back pain. Of these, 43% reported average back pain intensity in the mild range (1-4 on 0-10 rating scale) and 25% reported pain of moderate intensity (5-6 on 0-10 scale). Most respondents with back pain rated the interference of their pain on function as none to minimal. However, nearly 25% of those with back pain described it as frequent, of severe intensity (>or=7 on 0-10 scale), and as severely interfering with daily activities including social, recreational, family, and work activities. CONCLUSIONS: Back pain may be surprisingly common in persons with lower limb amputations, and, for some who experience it, may greatly interfere with function.

Activities of Daily Living↗

PubMed2001

Effect of trans-tibial prosthesis pylon flexibility on ground reaction forces during gait.

This study explored the effects of trans-tibial prosthesis pylon flexibility on ground reaction forces (GRFs) associated with walking and step-down. Four (4) active subjects with unilateral trans-tibial amputation and pylon lengths ranging from 4.9 cm to 25.9 cm were studied wearing an aluminium (rigid) pylon and a nylon (more flexible) pylon. Ground reaction forces were collected for the amputated limb during walking at pre-measured self-selected velocity and when stepping down from a 20 cm box. Pylon material significantly affected the magnitudes and patterns of GRFs in both tests. During walking, the most notable differences were seen in the anteroposterior (AP) direction. With the flexible pylon, the AP propulsive peak was greater (p=0.031), and the irregularities in the AP force curve were reduced. Additionally, when walking with the flexible pylon, the vertical peak associated with weight acceptance occurred earlier (p=0.010), the vertical terminal stance peak occurred later (p=0.012), and stance time was longer (p=0.010). During step-down, the vertical loading rate (p=0.010) and the peak vertical force (p=0.010) were greater with the more flexible pylon. Subjective feedback indicated that subjects could distinguish between the two pylons and felt that the nylon component was more comfortable, more flexible, and would enable them to walk more quickly. These results suggest that the pylon may be an influential component of the prosthesis with respect to gait and comfort, and that some degree of flexibility is desirable.

Adult↗

PubMed2000

Chronic phantom sensations, phantom pain, residual limb pain, and other regional pain after lower limb amputation.

OBJECTIVES: To determine the characteristics of phantom limb sensation, phantom limb pain, and residual limb pain, and to evaluate pain-related disability associated with phantom limb pain. DESIGN: Retrospective, cross-sectional survey. Six or more months after lower limb amputation, participants (n = 255) completed an amputation pain questionnaire that included several standardized pain measures. SETTING: Community-based survey from clinical databases. PARTICIPANTS: A community-based sample of persons with lower limb amputations. MAIN OUTCOME MEASURES: Frequency, duration, intensity, and quality of phantom limb and residual limb pain, and pain-related disability as measured by the Chronic Pain Grade. RESULTS: Of the respondents, 79% reported phantom limb sensations, 72% reported phantom limb pain, and 74% reported residual limb pain. Many described their phantom limb and residual limb pain as episodic and not particularly bothersome. Most participants with phantom limb pain were classified into the two low pain-related disability categories: grade I, low disability/low pain intensity (47%) or grade II, low disability/high pain intensity (28%). Many participants reported having pain in other anatomic locations, including the back (52%). CONCLUSIONS: Phantom limb and residual limb pain are common after a lower limb amputation. For most, the pain is episodic and not particularly disabling. However, for a notable subset, the pain may be quite disabling. Pain after amputation should be viewed from a broad perspective that considers other anatomic sites as well as the impact of pain on functioning.

Adult↗

PubMed1998

The role of ankle plantar flexor muscle work during walking.

Impaired ankle plantar flexor (APF) function is a frequent cause of gait limitations, but the role of the APF in the forward propulsion of the body remains controversial. To better understand both the direct and indirect effects of the APF during push-off and through advancement of the leg, mechanical work and inverse dynamic analyses were performed on 8 normal subjects during level walking. During push-off, 23.1 joules (J) of energy were generated, primarily by the APF, but only 4.2 J of this energy is transferred into the trunk. Ankle plantar flexor work is primarily used to accelerate the leg into swing. Most of the energy, 18.6 J, is recovered by transfer into the trunk at the end of swing. The timing of the energy transfers relative to the trunk motion imply that the APF contributes to the forward kinetic energy of the trunk but that other mechanisms likely account for the work used to raise the trunk against gravity.

Adult↗

PubMed1996

Energy transfer mechanisms as a compensatory strategy in below knee amputee runners.

Below knee amputee runners exhibit abnormalities in the mechanical work characteristics of the lower extremity musculature during stance phase. The most significant abnormality is a marked reduction in the mechanical work done in the stance phase prosthetic limb. Energy transfer across the hip joint to the trunk during deceleration of the swing phase leg may be an important energy distribution mechanism to compensate for the reduced work done during prosthetic stance phase. Five unilateral below knee amputee runners wearing the SACH prosthetic foot and 5 normal subjects were studied. All subjects ran at a controlled velocity of 2.8 ms(-1) while kinematic and ground reaction force data were collected. Using a four segment linked segment model and an inverse dynamics approach joint moments, muscle power outputs, mechanical work values and energy transfers across the hip were calculated. The total amount of energy transferred during swing phase and the energy transferred out of the swing phase leg into the trunk were both significantly greater than normal. Energy transfer mechanisms are important in influencing the lower extremity energetics during swing phase. In addition, the 74 percent increase in energy transfer out of the intact swing phase limb combined with the temporal characteristics of this energy flow suggests that energy transfer may be an adaptive mechanism that allows energy redistribution to the trunk which may partially compensate for the reduced power output of the stance phase prosthetic limb.

Adaptation, Physiological↗

PubMed1996

Mechanical work adaptations of above-knee amputee ambulation.

OBJECTIVE: To quantify the muscular adaptations of above-knee amputee patients' ambulation using an experimental and modeling approach. DESIGN: Nonrandomized controlled study. SETTING: A referral center for treatment of veterans with amputation. SUBJECTS: Eight normal ambulators and 8 nondysvascular above-knee amputee subjects wearing the same lightweight prostheses were studied with a gait analysis system, walking at self-selected speeds. MAIN OUTCOME MEASURES: Using an inverse dynamics linked segment model, the mechanical torque, power output, and work done were calculated at the hip, knee, and ankle joints. RESULTS: The mean concentric ankle plantarflexor work done was much greater for the normal subjects compared to the prosthetic limb in pushoff (25.2 +/- 3.7 J vs 4.9 +/- 2.1 J), but greatest for the intact limb of the amputee subjects (34.2 +/- 6.6 J). Also, the concentric hip extensor work done in early stance was greater for the intact limb of the amputee subjects than for normal subjects (9.9 +/- 5.5 J vs 3.6 +/- 2.6 J), presumably compensating for the coincident decreased pushoff of the prosthetic limb. Other compensatory mechanisms are also discussed. CONCLUSIONS: Increased joint torques and power outputs of the amputee subjects' intact limb compared to normal ambulation may be viewed as providing additional gait progression and upright stance during parts of the gait cycle when the amputated limb lacks needed active muscle support.

Adaptation, Physiological↗

PubMed1996

Rehabilitation in limb deficiency. 1. Gait and motion analysis.

This self-directed learning module highlights new advances in this topic area. It is part of the chapter on rehabilitation in limb deficiency in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article discusses normal gait, the influence of prosthetic alignment on amputee function, and the effects of prosthetic components on the metabolic costs and the biomechanical function of the amputee. The biomechanics of normal ambulation are presented as a background to enable the practitioner to gain an understanding of the typical gait adaptations that occur in below-knee and above-knee amputees. The effects of newer prosthetic components and socket designs on the biomechanical adaptations are reviewed. The metabolic costs of amputee ambulation are significantly greater than normal. The theoretical mechanisms for this are discussed, and the effects of newer socket designs, ultra-light-weight components, and energy-storing prosthetic components are presented.

Adaptation, Physiological↗

PubMed1993

Gait parameters of children with spastic diplegia: a comparison of effects of posterior and anterior walkers.

The purpose of this study was to compare the effects of posterior and anterior walkers on the gait parameters of five children with spastic diplegic cerebral palsy. Computer-based kinematic analysis was used to investigate differences in gait. Gait laboratory data indicated that use of the posterior walker (1) facilitated more upright posture in these subjects, as seen in decreased trunk and hip flexion during stance phase; (2) decreased double stance time; and (3) increased walking velocity. According to parent report, both the parents and their children preferred the posterior walker. Most parents also reported that when using the posterior walker, their children walked more normally with increased stability and interacted more easily with other children.

Ankle↗

PubMed1992

Insights into amputee running. A muscle work analysis.

Five young, active, unilateral below knee amputees wearing the SACH prosthetic foot, and six normal subjects participated in the study. Subjects ran at a controlled velocity of 2.8 m/s +/- 10% over a ground reaction force plate while being filmed with a video camera. Joint moments, power outputs and mechanical work characteristics were then calculated. During stance phase the amputee prosthetic limb exhibited a marked reduction in total work. There was a reduction in the mechanical work at the knee and the prosthetic foot/ankle with a compensatory increase in mechanical work by the hip musculature. The intact stance phase limb mechanical work characteristics were not significantly different from normal. The hip flexors were the only muscle group in the swing phase prosthetic limb with a significant increase in muscle work compared with normal subjects. The intact swing phase limb in contrast exhibited a marked increase in concentric muscle work by the hip flexors and eccentric muscle work by the knee flexors in early swing phase, and an increase in concentric hip extensor and eccentric knee flexor muscle work in late swing phase. The major compensatory patterns, therefore, that allow below knee amputees to run appear to be an increase in stance phase hip muscle work on the prosthetic limb and increased hip and knee muscle work on the intact limb during swing phase.

Amputation, Surgical↗

PubMed1991

Joint moment and muscle power output characteristics of below knee amputees during running: the influence of energy storing prosthetic feet.

Stance phase joint moments, muscle power outputs and mechanical energy characteristics were determined in five normal and five below knee amputee subjects running at 2.8 m s-1. The amputees were studied sequentially on three different prosthetic feet: the SACH foot (solid ankle cushion heel), and two energy storing feet, Seattle and Flex. While wearing the SACH foot, the amputees exhibited major alterations in the distribution and magnitude of muscle power output and muscle work: (1) the total work done by the lower extremity was reduced; (2) the hip extensors became the main source of energy absorption and generation, while in normal subjects the ankle plantarflexors were the major energy generators and the knee extensors the major energy absorbers; (3) the eccentric and concentric knee extensor power outputs were reduced and an abnormal concentric knee flexor power output was noted immediately after heel contact. In four of the amputees, energy storing feet resulted in improvements in the power output and mechanical work characteristics of the lower extremity: (1) the energy storing prosthetic feet generated 2-3 times greater energy than the SACH foot; (2) with the Flex foot the amputees exhibited a more normal pattern and magnitude of hip and knee extensor muscle work. One of the subjects, however, exhibited increased abnormalities with the energy storing prosthetic feet. The amount of energy restored relative to the amount of energy absorbed by each of the prosthetic feet was greater with the energy storing feet than the SACH foot (Flex 84%, Seattle 52%, SACH 31%).

Amputation Stumps↗

PubMed1991

Biomechanical analysis of the influence of prosthetic feet on below-knee amputee walking.

Although energy storing prosthetic feet have achieved widespread clinical acceptance, the effect of these components on the biomechanics of below-knee amputee gait is poorly understood. The purpose of this study was to determine the biomechanical adaptations used by the below-knee amputee while wearing a conventional prosthetic foot and to assess the influence of energy storing prosthetic feet on these adaptations. Mechanical power outputs of the lower extremity in five normal and five below-knee amputee subjects using the SACH, Seattle and Flex feet were studied. Ground reaction forces and kinematic data were collected at a walking speed of 1.5 m/s and were used to determine the muscular power outputs of the lower extremity during stance. Consistent patterns of muscular power output at the hip and knee of the residual limb occur. While wearing the SACH foot, negligible energy generation occurs at the prosthetic foot during pushoff. A decrease in energy absorption at the knee during the first half of stance and an increase in energy generation by the hip extensors were the major adaptations noted in the proximal muscle groups. Compared to the SACH foot, the energy storing feet demonstrated increased energy generation during pushoff. Despite the improvements in the performance of the energy storing prosthetic feet, no significant differences were found in the pattern or magnitude of knee and hip power outputs compared to the SACH foot.

Adult↗

PubMed1990

The effects of age and peripheral vascular disease on the circulatory and mechanical response of skin to loading.

The skin and subcutaneous soft tissues of amputation residual limbs are required to withstand externally applied loads of greater magnitude than similar tissues of the intact lower limb. Increased age and poor circulatory status may contribute to the increased risk of tissue injury seen in this population. This study evaluates the effects of age and circulatory status as risk factors for skin injury resulting from externally applied forces. Twelve young control (YC), six elderly control (OC) and 11 subjects with peripheral vascular disease (PVD) were studied. After base-line ankle arm index (AAI) measurements, TcPO2 electrodes were applied 10 cm below the knee over the medial surface of the tibia and the muscle belly of tibialis anterior. TcPO2 measurements and tissue displacements were obtained under the influence of incremented, normally oriented, external loads. The sensitivity of the tissues to applied loads was determined by calculating the load at which the TcPO2 reached zero. The stiffness of the tissues (displacement/load) was calculated under high (greater than 40 mm Hg) and low (less than 20 mm Hg) loading conditions. No difference was noted in tissue sensitivity to applied loads between the OC and YC populations. The TcPO2 decreased to zero in the PVD population at significantly lower applied loads than both the OC and YC populations. The tissue stiffness of the PVD and the OC populations over bone was greater than the YC population, but no significant differences were noted between the PVD and the OC populations. In summary, increased age does not result in a greater tissue sensitivity to externally applied loads, in spite of the demonstrated increased tissue stiffness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Reflex sympathetic dystrophy in an amputee: case study.

Reflex sympathetic dystrophy (RSD) has been described primarily in the upper extremity and is infrequently considered part of the differential diagnosis of postamputation pain. The manifestations of autonomic dysfunction may mimic other potential diagnoses of postoperative stump pain. We report a 47-year-old man who developed RSD of the knee during the mobilization phase after below-knee amputation for atherosclerotic peripheral vascular disease. The diagnosis was made by clinical examination, radiography, and scintigraphy without the need for any invasive studies. The characteristic diagnostic findings for the knee during the acute phase are emphasized and the therapy described.

Amputees↗

PubMed1989

Circulatory and mechanical response of skin to loading.

We investigated the tolerance of skin to mechanical loading over the tibia and over the tibialis anterior muscle in 12 normal volunteers. Surface load, subcutaneous tissue pressure, skin deformation under load, and transcutaneous partial pressure of oxygen (TcPO2) were simultaneously monitored. The skin over bone showed a significantly stiffer load deformation relationship than the skin over muscle (p less than 0.001). The displacement required to reduce TcPO2 to 0 over bone, 1.1 +/- 0.3 mm (mean +/- standard deviation), was significantly less than that required over tibialis anterior muscle, 5.4 +/- 1.1 mm (p less than 0.001). The applied pressure required to reduce TcPO2 to 0 was significantly greater for skin over muscle (71 +/- 16 mm Hg) than for skin over bone (42 +/- 8 mm Hg) (p less than 0.001). However, the subcutaneous pressure required to reduce TcPO2 to 0 was not significantly different for skin over muscle (36 +/- 11 mm Hg) than for skin over bone (28 +/- 10 mm Hg) (p greater than 0.05). Our results indicate that skin over muscle tolerates greater locally applied loads and deformations because the pressure is lower within the tissue than when similar loads and deformation are applied to skin over bone. Cutaneous perfusion, as indicated by TcPO2, seems to be linked more closely to the subcutaneous tissue pressure than to the surface load or deformations. These results provide some data for predicting mechanical and physiologic response to locally applied loads such as those that may be encountered in prosthetic wear.

Adult↗

PubMed1989

Prosthetic feet.

Explore the source record for details and available documents.

Biomechanical Phenomena↗

PubMed1988

Foot and ankle biomechanics in walking and running. A review.

The biomechanics of the foot and ankle are initially discussed, as a series of isolated joints and segments, and subsequently as an integrated unit during the functional activities of walking and running. The kinematics and kinetics of the foot and ankle during the three major components of stance phase are reviewed. The first component, between foot contact and foot flat, is characterized primarily by force absorption. The portion of the gait cycle between foot flat and heel off is associated with controlled forward progression of the center of mass and maximum mobility of the transverse tarsal joint. In the third phase, supination of the foot results in increased rigidity of the transverse tarsal joint, and therefore improved force transmission. The controversy regarding the function of the triceps surae during this phase of the gait cycle is discussed.

Ankle↗

PubMedDate not supplied

Effect of alterations in prosthetic shank mass on the metabolic costs of ambulation in above-knee amputees.

The metabolic costs of above-knee amputee ambulation are significantly greater than normal. The role of prosthetic mass and mass distribution on the metabolic costs of walking has received limited study. The metabolic costs of eight unilateral traumatic above-knee amputees were therefore studied under varying mass conditions. All of the subjects were active young amputees with a common prosthetic prescription, which included a total contact ischial containment, suction suspension socket with a graphlite knee assembly and a hydraulic unit, with a Seattle Light Foot (Model and Instrument Development, Seattle, WA). Expired gases were collected during over-ground ambulation at their self-selected walking speed and at three control speeds (.6, 1.0 and 1.5 m/s). The expired volumes and gas concentrations were measured, and the metabolic cost (ml/kg/m) at each ambulation speed was calculated. Data were collected on two further sessions with the addition of 0.68 and 1.34 kg to the center of mass of the shank, after a 1 wk acclimatization period. Results show that in the unweighted condition, the self-selected walking speed had the lowest metabolic energy expenditure and that the addition of weight to the shank did not significantly alter the metabolic costs of ambulation at any of the speeds studied. The common request for lighter weight prostheses does not appear to be based on the metabolic costs of ambulation.

Adult↗