Knee Disarticulation Amputees Research Articles

A combined kinematic and kinetic analysis at the residuum/socket interface of a knee-disarticulation amputee

The bespoke interface between a lower limb residuum and a prosthetic socket is critical for an amputee's comfort and overall rehabilitation outcomes. Analysis of interface kinematics and kinetics is important to gain full understanding of the interface biomechanics, which could aid clinical socket fit, rehabilitation and amputee care. This pilot study aims to investigate the dynamic correlation between kinematic movement and kinetic stresses at the interface during walking tests on different terrains.One male, knee disarticulation amputee participated in the study. He was asked to walk on both a level surface and a 5° ramped surface. The movement between the residuum and the socket was evaluated by the angular and axial couplings, based on the outputs from a 3D motion capture system. The corresponding kinetic stresses at anterior-proximal (AP), posterior-proximal (PP) and anterior-distal (AD) locations of the residuum were measured, using individual stress sensors.Approximately 8° of angular coupling and up to 32 mm of axial coupling were measured when walking on different terrains. The direction of the angular coupling shows strong correlation with the pressure difference between the PP and AP sensors. Higher pressure was obtained at the PP location than the AP location during stance phase, associated with the direction of the angular coupling. A strong correlation between axial coupling length, L, and longitudinal shear was also evident at the PP and AD locations i.e. the shortening of L corresponds to the increase of shear in the proximal direction. Although different terrains did not affect these correlations in principle, interface kinematic and kinetic values suggested that gait changes can induce modifications to the interface biomechanics.It is envisaged that the reported techniques could be potentially used to provide combined kinematics and kinetics for the understanding of biomechanics at the residuum/socket interface, which may play an important role in the clinical assessment of prosthetic component settings, including socket fit quality.

A pressure and shear sensor system for stress measurement at lower limb residuum/socket interface

A sensor system for measurement of pressure and shear at the lower limb residuum/socket interface is described. The system comprises of a flexible sensor unit and a data acquisition unit with wireless data transmission capability. Static and dynamic performance of the sensor system was characterised using a mechanical test machine. The static calibration results suggest that the developed sensor system presents high linearity (linearity error ≤ 3.8%) and resolution (0.9 kPa for pressure and 0.2 kPa for shear). Dynamic characterisation of the sensor system shows hysteresis error of approximately 15% for pressure and 8% for shear. Subsequently, a pilot amputee walking test was conducted. Three sensors were placed at the residuum/socket interface of a knee disarticulation amputee and simultaneous measurements were obtained during pilot amputee walking test. The pressure and shear peak values as well as their temporal profiles are presented and discussed. In particular, peak pressure and shear of approximately 58 kPa and 27 kPa, respectively, were recorded. Their temporal profiles also provide dynamic coupling information at this critical residuum/socket interface. These preliminary amputee test results suggest strong potential of the developed sensor system for exploitation as an assistive technology to facilitate socket design, socket fit and effective monitoring of lower limb residuum health.

Gait adjustments in obstacle crossing, gait initiation and gait termination after a recent lower limb amputation

Objective: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process. Design: Prospective and descriptive study. Subjects: Fourteen subjects with a recent transfemoral, knee disarticulation or transtibial amputation. Methods: Subjects stepped over an obstacle and initiated and terminated gait at four different times during the rehabilitation process. Outcome measures: Success rate, gait velocity and lower limb joint angles in obstacle crossing, centre of pressure shift and peak anteroposterior ground reaction force in gait initiation and termination. Results: In obstacle crossing amputees increased success rate, gait velocity and swing knee flexion of the prosthetic limb. Knee flexion in transfemoral and knee disarticulation amputees was not sufficient for safe obstacle crossing, which resulted in a circumduction strategy. In gait initiation and termination amputees increased the anteroposterior ground reaction force and the centre of pressure shift in the mediolateral direction in both tasks. Throughout the rehabilitation process the centre of pressure was shifted anteriorly before single-limb stance on the trailing prosthetic limb in gait initiation, whereas in gait termination the centre of pressure in single-limb stance remained posterior when leading with the prosthetic limb. Conclusion: Subjects with a recent amputation develop adjustment strategies to improve obstacle crossing, gait initiation and gait termination. Innovations in prosthetic design or training methods may ease the learning process of these tasks.

Correlation of residual limb length and gait parameters in amputees

There is a lack of objective data on acceptable transection levels for transfemoral amputation. We retrospectively correlated the residual limb length of 13 young, athletic transfemoral and knee disarticulation amputees with temporal-spatial, kinematic, and kinetic outcomes after gait analysis. It was hypothesised that shorter residual limb lengths would correlate with greater gait deviations. Patients' residual femoral lengths ranged from 57% to 100% of their intact femoral length. With the exception of one patient, pelvic tilt excursion was inversely related to residual limb length. Limb length did not significantly correlate with any other temporal-spatial, kinematic, or kinetic parameter investigated. Consequently, these results suggest that if the femur is at least 57% of the length of the contralateral femur, length does not dramatically alter gait. This implies that surgeons may have more flexibility to amputate at a higher level to preserve soft tissue quality and improve prosthetic fitting without sacrificing gait function.

Skin problems of the stump and hand function in lower limb amputees

The aim of this study was to investigate the relationship between liner-related skin problems of the stump in patients with a lower limb amputation and impaired hand function. Sixty patients who were treated in a rehabilitation hospital from 1998-2006 were included in an historic cohort study. Data were collected concerning the amputation, skin problems of the stump, co-morbidity, hand function, the prosthesis, liner use and mobility score. The study population consisted of 50 trans-tibial and 10 knee disarticulation amputees, 43 male and 17 female, with a mean age of 62.3 years. The majority (63%) had a vascular reason for amputation. Blisters, folliculitis, rash and surface wounds on the stump were operationalized as being liner related. In patients with an impaired hand function, 70% had experienced liner-related skin problems of the stump, whereas 32% of the patients with a normal hand function had experienced skin problems (p = 0.035). This study shows that impaired hand function poses an increased risk for skin problems in the amputation stump in patients with a lower limb amputation and liner use in their prosthesis.

Residual limb length and gait kinematics in transfemoral and knee disarticulation amputees: Preliminary results

0.80 0.30 15.3 8.2 37.9 6.0 Cluster 9 0.9 0.2 13.6 5.2 0.61 0.40 33.3 6.4 39.0 8.8 involvement by showing a discrete foot drop during swing phase. The ankle of patients in cluster 3 was in plantar flexion during the main part of the gait cycle. Because of the characteristics this cluster was called reversed second ankle rocker with premature knee extension. Cluster 4, double bump with jump knee, was characterised by a double bump pattern at the ankle and an increased flexion at the hip (p4/1, 4/5, 4/7, 4/8 and 4/9 < 0.001) and the knee. Patients of cluster 5 were presented with a recurvatum knee. These children walked slower (significantly different between all clusters p < 0.001 except for cluster 9) compared to normal subjects, with a clearly decreased ankle power generation at push off (p5/1, 5/2, 5/3, 5/4, 5/6 and 5/7 < 0.001). Cluster 6 was characterised by a neutral to dorsiflexed ankle, with a double bump pattern in the sagittal plane. Therefore this cluster was called apparent equinus. Due to the reversed second ankle rocker, these patients had a large power absorption at the ankle at midstance (p6/2, 6/4, 6/7 and 6/8 < 0.001). Several features of cluster 6 indicated a stiff knee pattern and a flexed hip. Cluster 7, mild crouch, demonstrated an increased dorsiflexion at loading response (p7/1, 7/2, 7/3, 7/5 and 7/9 < 0.001). Also typical for this group was the increased knee flexion throughout the stance phase. The most outstanding feature of cluster 8 was the severe crouch pattern. Furthermore the ankle showed a lack of plantar flexion during the gait cycle (p8/2, 8/3, 8/5 and 8/9 < 0.0001). Patients in cluster 9 demonstrated continuous plantar flexion at the ankle and flexion at the hip and knee, and could therefore be described as a typical triple flexion pattern. The S.D. and mean of five important parameters were illustrated in Table 1.

Why knee disarticulation (through-knee amputation) is appropriate for non ambulatory patients

Purpose : To determine the reason why 79% of knee disarticulation amputees had not received a prosthesis. Method : A 10 year survey was carried out of all patients who had undergone a knee disarticulation at our medical centre. Results : Seventeen of the 37 patients that had not received a prosthesis were recognized to be non-ambulators prior to the surgery. Four patients died after the surgery and in 16 of the patients their general condition limited functional ambulation. An effort had been made to ambulate the patients but had failed. Conclusions : From a biomechanical point of view many advantages are to be gained for sedentary and bedridden amputees when the level of amputation is through-the-knee.

Walking speed of normal subjects and amputees: aspects of validity of gait analysis.

This study investigated some aspects of the validity of walking speed recording in 15 normal subjects, 16 trans-femoral amputees and 8 knee disarticulation amputees. The variability and test-retest reliability of walking speed and the influence of simultaneous recording of EMG and goniometry on comfortable and fast walking speeds were studied. The variability between sessions was mainly determined by the variance within each session. The variance of speed within sessions while walking with fast speed, was higher when walking without equipment than when walking with equipment. The variances of speed within sessions of the normal subjects were higher than those for both amputee groups. The test-retest reliability, expressed by the intra-class correlation coefficient, was good: between 0.83 and 0.98. The speed when walking without equipment was significantly higher both in normal subjects and amputees than the speed when walking with equipment.

Stubby prostheses: An alternative to conventional prosthetic devices

Stubby prostheses offer potential advantages over conventional prosthetic devices in terms of safety, stability, and energy efficiency. Although cosmesis is compromised in the process, these short nonarticulated pylon prostheses may be a viable option to consider in bilateral A-K or knee disarticulation amputee patients under the following circumstances: (1) as a training tool to determine whether progression to full-length articulated devices is feasible; (2) as permanent prostheses for the patient whose primary need for ambulation is within his own home; (3) for the elderly bilateral amputee in whom ambulation is feasible but safety and energy efficiency are of particular importance; and (4) as a definitive device in the patient who expresses a preference for them. Two patients who have become successful users of stubby prostheses are presented to illustrate these points.

Amputations of the Leg for Peripheral Vascular Insufficiency

From July 1964 to July 1970, 193 major lower-extremity amputations were performed on 177 consecutive patients for ischemia by the Prosthetics Research Study team. Of these amputations, 101 were performed in diabetic patients; eighty-three in non-diabetic patients; and four in patients with Buerger's disease. The initial levels of amputation were above-the-knee in twenty-eight, below-the-knee in 157, Syme in two, and knee disarticulation in three. The final levels were above the knee in forty, knee disarticulation in three, below the knee in 145 (two bilateral) and Syme in two (one bilateral). Selection of the level for amputation, the technique of below-the-knee amputation, the rigid dressing, immediate postsurgical prosthetic regimen, the procedure for weight-bearing and ambulation, and the method of follow-up are described. The results in terms of rehabilitation of the patients to a functional status are analyzed. Only nine of the 132 below-the-knee and Syme amputees and eight of the thirty-one above-the-knee and knee-disarticulation amputees who were fitted with a definitive prosthesis failed to gain independence out of the home. Seventy-four of the eighty-one below-the-knee and Syme amputees, who were sixty years old or older, were fitted with a definitive prosthesis and gained full independence out of their homes. Twelve below-the-knee amputations failed to heal and reamputation above the knee was required. Of these failures, seven could be attributed to incorrect selection of the level and five to inadequate postoperative management. It is concluded that with strict adherence to the precepts outlined with respect to the selection of the level, surgical technique, and postsurgical management. consistently high rates of healing and rehabilitation can be achieved after below-the-knee amputation for vascular insufficiency.