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PubMed1992

Interface shear stresses during ambulation with a below-knee prosthetic limb.

Shear stresses on a residual limb in a prosthetic socket are considered clinically to contribute to tissue breakdown in below-knee amputees. When applied simultaneously with normal stresses, they can cause injury within the skin or can generate an abrasion on the surface. To gain insight into shear stresses and parameters that affect them, interface stresses were recorded on below-knee amputee subjects during walking trials. On the tibial flares, resultant shear ranged from 5.6 kPa to 39.0 kPa, while on the posterior surface it ranged from 5.0 kPa to 40.7 kPa. During stance phase, anterior resultant shears on a socket were directed toward the apex while posterior resultant shears were directed downward approximately perpendicular to the ground. Waveform shapes were usually double-peaked, with the first peak at 25% to 40% into stance phase and the second peak at 65% to 85% into stance. Application of these results to residual limb tissue mechanics and prosthetic design is discussed.

Adult↗
PubMedDate not supplied

A noncontact sensor for measurement of distal residual-limb position during walking.

A simple noncontact device was implemented for measuring the position of the distal residual limb relative to the prosthetic socket during ambulation. The device was a small and lightweight photoelectric sensor positioned within a frame mounted immediately beneath the socket. Calibration tests showed that the sensor had a displacement range of 60.0 mm. The root-mean-square error for all sources of error considered (different reflective surfaces, peak-to-peak signal noise, drift, nonlinearity, different surface tilt angles, surface curvature, and wetness [simulating sweating]) was <1.95% full-scale output. We used the sensor in a preliminary study on a unilateral, transtibial amputee with diabetes to assess pistoning during ambulation. Results showed an average 41.7 mm proximal displacement during swing phase relative to stance phase. When the subject was walking on a flat surface, pistoning was significantly less (p = 0.000) with a supracondylar strap compared with no supracondylar strap, although the difference was not substantial (0.8 mm). A 5 min rest period caused the limb to displace proximally in the socket approximately 4.8 mm during subsequent walking trials, possibly reflecting limb enlargement and thus a more proximal position in the socket after the rest period. The device can potentially be used in prosthetics research for evaluating clinical features that may affect limb position and pistoning and thus fit.

Amputation Stumps↗
PubMed1999

Amputations and prosthetics.

The author presents in a condensed way an overview of the principles of limb amputations and further treatment of patients who underwent such a procedure. The metabolic cost of walking, load transfer, and wound healing are reviewed in a concise manner. Particular attention is given to blood supply to the wound and methods to determine adequate perfusion with a clear analysis of the pro and cons of the Doppler method. Pediatric amputations, because of their specificity, are considered apart. Disarticulation of limbs is the method of choice in children, because of it retains growth potential of the bone and prevents bony overgrowth of the stump. The article discusses the main indications for limb amputations: trauma, peripheral vascular disease, musculoskeletal tumors and gas gangrene. In every case the specificity of the amputation is considered by the author. Postoperative care is also presented, with a short description of possible complications. Pain is the most common and treatment strategies should be similar to those used in treating patients with major reflex sympathetic causalgia. Edema, joint contracture, wound failure and dermatologic problems are all shortly reviewed. The last part of the article treats with the principles of prosthetics in both the upper and lower limb. These principles are presented basing on the level of amputation: for the upper limb hand, transradial, transhumeral amputations and shoulder disarticulation. For the lower limb foot and ankle, transtibial and transfemoral amputations are considered.

Adult↗
PubMed2003

Controversies in amputation surgery.

Amputation surgery should be the first step in the rehabilitation of a patient with a nonfunctional limb, rather than the final step in treatment. When faced with a difficult decision regarding lower extremity amputation compared with attempted limb reconstruction, expectations for a reasonable outcome must be determined. After reasonable goals have been set, the surgery should be directed toward interfacing with a prosthetic limb. Current surgical techniques of lower extremity amputation, paying special attention to transosseous versus disarticulation amputation, help to optimize prosthetic limb fitting and functional rehabilitation. With the evolution of end-bearing amputation levels, there is resurgent interest in the bone bridging technique of Johann Ertl and interest in a new pneumatic immediate postoperative prosthetic limb fitting system.

Amputation, Surgical↗
PubMed1995

The effect of prosthetic alignment on relative limb loading in persons with trans-tibial amputation: a preliminary report.

The prosthetic sockets of 14 independent persons with unilateral trans-tibial (BK) amputation were mounted on an adjustable alignment pylon. Vertical ground reaction forces were recorded in neutral prosthetic alignment and in 10 degrees of prosthetic socket varus, valgus, flexion, and extension. Stance phase time, peak vertical ground reaction force, and impulse were all found to be increased on the sound limb when compared to the amputated residual limb. Significant differences were found in stance phase time and peak vertical ground reaction force when comparing malaligned with neutrally aligned prosthetic limbs. Significant differences were also seen in impulse between neutrally aligned and malaligned prosthetic limbs. The results suggest that prosthetic malalignment in persons with trans-tibial amputation leads to increased loading of the contralateral limb.

Adult↗
PubMed1996

Parametric analysis using the finite element method to investigate prosthetic interface stresses for persons with trans-tibial amputation.

A finite element (FE) model of the below-knee residual limb and prosthetic socket was created to investigate the effects of parameter variations on the interface stress distribution during static stance. This model was based upon geometric approximations of anthropometric residual limb geometry. The model was not specific to an individual with amputation, but could be scaled to approximate the limb of a particular subject. Parametric analyses were conducted to investigate the effects of prosthetic socket design and residual limb geometry on the residual limb/prosthetic socket interface stresses. Behavioral trends were illustrated via sensitivity analysis. The results of the parametric analyses indicate that the residual limb/prosthetic socket interface stresses are affected by variations in both prosthetic design and residual limb geometry. Specifically, the analyses indicate: 1) the residual limb/prosthetic liner interface pressures are relatively insensitive to the socket stiffness; 2) the stiffness of the prosthetic liner influences the interface stress distribution for both the unrectified and patellar-tendon-bearing (PTB) rectified models-the external load state appears to influence the interface pressure distribution, while the prosthetic socket rectification appears to influence the interface shear stress distribution; 3) the interface pressures are very sensitive to the prosthetic rectification; 4) the shape and relative bulk of soft tissue may significantly influence the interface pressure distribution; 5) the interface pressure distribution is also influenced by the residual limb length; and 6) the stiffness/compliance of the residual limb soft tissues may significantly alter the interface pressure distribution.

Amputation, Surgical↗
PubMed2004

A picture of amputees and the prosthetic situation in Haiti.

PURPOSE: The purpose of this study is to present the situation of Haitian amputees and to outline some of the major barriers in Haiti that prevent people from receiving prosthetic treatment. METHOD: Interviews were conducted with amputees throughout Haiti using a 42-question questionnaire. Additionally, interviews were conducted with traditional healers, health care workers, and leaders of handicap associations. Each interview was manuscripted and the data were subsequently coded and analysed in the USA. RESULTS: There are three full-time prosthetic shops and two part-time prosthetic shops in Haiti, all of which are severely limited in the scope of services they are able to provide amputees due to insufficient supplies and inadequately trained personnel. Only 25% of the 164 amputees interviewed had ever had a prosthetic limb. Typically prosthetic treatment is inaccessible and unaffordable for amputees, which prevents many from seeking treatment. The most common cause of amputation in Haiti is infection, followed by motor vehicle accidents. CONCLUSION: There must be additional cooperation between Haitian patients, doctors, traditional healers, prosthetists, and government officials in order to provide more adequate prosthetic care. Prosthetic treatment in Haiti can be successful with cooperation of different entities, proper rehabilitation therapy, adequately trained personnel, and development of culturally appropriate limbs.

Adolescent↗
PubMed2006

Skin problems in lower limb amputees: a systematic review.

PURPOSE: Skin problems of the stump in lower limb amputees are relative common in daily rehabilitation practice, possibly impeding prosthetic use. This impediment may have great impact in daily life. Our objective was to review literature systematically concerning incidence and prevalence of skin disorders of the stump in lower limb amputees. METHOD: A literature search was performed in several medical databases (MEDLINE, CINAHL, EMBASE, RECAL) using database specific search strategies. Reference lists in the identified publications were used as threads for retrieving more publications missed in the searches. Only clinical studies and patient surveys were eligible for further assessment. RESULTS: 545 publications were initially found. After selection, 28 publications were assessed for research methodology. Only one publication fulfilled the selection criteria. The prevalence of skin problems in a series of 45 lower leg amputees of 65 years and older was 16%. CONCLUSIONS: Prevalence and incidence of skin problems of the stump in lower limb amputees are mainly unknown.

Amputation Stumps↗
PubMed2005

Factor structure of the Trinity Amputation and Prosthesis Experience Scales (TAPES) with individuals with acquired upper limb amputations.

OBJECTIVES: To investigate the factorial composition of the Trinity Amputation and Prosthesis Experience Scales (TAPES), a multidimensional assessment of adaptation to amputation and prosthesis, for use with individuals with acquired upper limb amputations. DESIGN: Cross-sectional survey of members of the British Limbless Ex-Service Men's Association. RESULTS: A total of 101 individuals (men, 100; mean age, 73.8 yrs, SD 11.94) with acquired upper limb amputations (98 traumatic cases) completed the TAPES. Principal components analyses with varimax rotation revealed four psychosocial subscales (general adjustment, social adjustment, optimal adjustment, and adjustment to limitation), four activity-restriction subscales (restriction of lifestyle, social restriction, occupational restriction, and restriction of mobility), and a single prosthesis-satisfaction subscale. Each of these subscales had high internal reliability. CONCLUSIONS: The TAPES structure can be meaningfully represented in terms of nine internally consistent subscales. Additional research needs to be done on the TAPES for use with individuals with upper limb amputations. In particular studies of the scales, predictive validity is warranted.

Aged↗
PubMed1977

Complete brachial plexus lesions: a ten-year follow-up of twenty cases.

Twenty patients with complete brachial plexus lesions were reviewed approximately nine and a half years after injury. Thirteen were amputees and seven had received no surgical treatment. Amputation did not alleviate pain and a prosthesis was frequently of no greater use of the patient than the useless limb it replaced: only two of the thirteen amputees were true prosthetic users and they both had dominant limb involvement, the rest adapting easily to being one-handed. Initial treatment should therefore be conservative, with intensive rehabilitation and retraining. It is recommended that amputation should not be considered until a year after injury and only if the flail limb causes repulsion, prevents sporting activities or if the patient has difficulty in converting to the non-dominant limb. In no instance should smputation be done for relief of pain.

Amputation, Surgical↗
PubMed1993

Gait analysis of dysvascular below-knee and contralateral through-knee bilateral amputees: a preliminary report.

Four elderly peripheral vascular insufficiency below-knee amputees, average age 58, underwent contralateral through-knee amputation for gangrene. All four became household ambulators with end-weight bearing designed prosthetic sockets and four-bar linkage knees. Gait analysis was performed with two AMTI (Newton, Mass) Biomechanics Force Platforms and a Watsmart Motion Monitoring System (Waterloo, Ontario). All four were observed to apparently "lock" the four-bar linkage prosthetic knee into extension during midstance and double limb support phases of gait. All subjectively felt that their through-knee limb was their more stable limb. Weight-bearing occurred during 63% of the gait cycle on the below-knee limb, 54% on the through-knee limb, and 17% in double limb support. Walking propulsion, as measured by forefoot impulse, was similar in the two limbs. The first peak of vertical force, corresponding to the elevation of the center of body weight as it passes over the weight-bearing limb, averaged 98% of body weight on the through-knee limb and only 93% on the below-knee limb. The second peak, corresponding to the kinetic energy of the falling trunk and muscle function providing linear acceleration of the center of body weight during propulsion, averaged 96% of body weight on the through-knee limb, and only 73% on the below-knee limb. Progression of the center of pressure, a qualitative measure of limb stability, was more orderly in the through-knee limbs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2001

Problems with excessive residual lower leg length in pediatric amputees.

We studied six pediatric amputees with long below-knee residual limbs, in order to delineate their functional and prosthetic situations, specifically in relation to problems with fitting for dynamic-response prosthetic feet. Three patients had congenital pseudoarthrosis of the tibia secondary to neurofibromatosis, one had fibular hemimelia, one had a traumatic amputation, and one had amputation secondary to burns. Five patients had Syme's amputations, one had a Boyd amputation. Ages at amputation ranged from nine months to five years (average age 3 years 1 month). After amputation, the long residual below-knee limbs allowed fitting with only the lowest-profile prostheses, such as deflection plates. In three patients, the femoral dome to tibial plafond length was greater on the amputated side than on the normal side. To allow room for more dynamic-response (and larger) foot prostheses, two patients have undergone proximal and distal tibial-fibular epiphyseodeses (one at age 5 years 10 months, the other at 3 years 7 months) and one had a proximal tibial-fibular epiphyseodesis at age 7 years 10 months. (All three patients are still skeletally immature.) The families of two other patients are considering epiphyseodeses, and one patient is not a candidate (skeletally mature). Scanogram data indicate that at skeletal maturity the epiphyseodesed patients will have adequate length distal to their residual limbs to fit larger and more dynamic-response prosthetic feet.

Amputees↗