Eva Haggstrom

Socket Versus Bone-Anchored Trans-Femoral Prostheses: Hip Range of Motion and Sitting Comfort:

This is the first study to report on hip range of motion (ROM) among active prosthesis users, when wearing and not wearing a trans-femoral socket prosthesis and to compare with individuals rehabilitated with an osseointegrated bone-anchored prosthesis. In addition, discomfort when sitting with the prosthesis is reported in both groups. The study group all had a non-vascular amputation and were divided into those supplied with a socket prosthesis (S group) (n = 43, mean age 51 years, 74% men) or a bone-anchored prosthesis (OI group) (n = 20, mean age 46 years, 75% men). Active hip ROM was measured with a goniometer, and self-reported problems with discomfort when sitting were recorded. The hip motion decreased in all directions when wearing the socket prosthesis compared to without it (P < 0.001 for all directions), and 37% of the subjects had less than 90° of hip flexion when wearing their prosthesis. Discomfort when sitting was reported among 44% (n = 19) in the S group and was more common among individuals with less than 90° of hip flexion motion (P = 0.025). In the OI group, no restriction in hip motion was measured with the prosthesis, and no subject had less than 90° of flexion and 5% (n = 1) reported discomfort when sitting. This study shows that a trans-femoral prosthetic socket significantly reduces the ROM of the hip and that discomfort when sitting is common among individuals wearing such prostheses. Further, the study confirms that individuals using a bone-anchored prosthesis have no restricted hip motion with the prosthesis and report very few problems with discomfort when sitting.

Monitoring of the load regime applied on the osseointegrated fixation of a trans-femoral amputee: A tool for evidence-based practice

This study aimed to provide a description of the continuous recording of the true load regime experienced during daily living by the abutment of a trans-femoral amputee fitted with an osseointegrated fixation. The specific objectives: (i) To present an apparatus and a procedure allowing recording of the load regime, and (ii) an example of the raw data and six performance indicators of the usage of the prosthesis obtained with this method. A subject was monitored for a period of 5 hours as he went about his daily activities. The load regime was directly measured and recorded using a commercial transducer and data logger. The overall load profile presented alternative periods of variable length of inactivity (64%) and activity (36%), respectively. The maximum load applied on the mediolateral, anteroposterior and the long axes represented 21%, 21% and 120% of the body weight, respectively. The anteroposterior, mediolateral and long components of the impulse were 395 kN.s, 359 kN.s and 2,323 kN.s, respectively. The amputee generated a total of 2312 gait cycles of the prosthetic leg, giving an approximate overall cadence of 8 stride/min. Preliminary outcomes indicated that the proposed method was an improvement on the current techniques as it provided the true loading and actual usage of the prosthesis during daily living. This study is a stepping stone in the development of future affordable, on-board and user-friendly load recording systems that can be used in evidence-based practice.

Load on osseointegrated fixation of a transfemoral amputee during a fall: loading, descent, impact and recovery analysis.

Falling represents a health risk for lower limb amputees fitted with an osseointegrated fixation mainly because of the potential damage to the fixation. The purpose of this study was to characterize a real forward fall that occurred inadvertently to a transfemoral amputee fitted with an osseointegrated fixation while attending a gait measurement session to assess the load applied on the residuum. The objective was to analyze the load applied on the fixation with an emphasis on the sequence of events, the pattern and the magnitude of the forces and moments. The load was measured directly at 200 Hz using a six-channel transducer. Complementary video footage was also studied. The fall was divided into four phases: Loading (240 ms), descent (620 ms), impact (365 ms) and recovery (2495 ms). The main impact forces and moments occurred 870 ms and 915 ms after the heel contact, and corresponded to 133% BW and 17 % BWm, or 1.2 and 11.2 times the maximum forces and moments applied during the previous steps of the participant, respectively. This study provided key information to engineers and clinicians facing the challenge to design equipment, and rehabilitation and exercise programs to restore safely the locomotion of lower limb amputees.

Vibrotactile evaluation: osseointegrated versus socket-suspended transfemoral prostheses.

This study investigated detection thresholds of vibrometric stimuli in patients with transfemoral amputation supplied with osseointegrated (OI) and socket-suspended prostheses. It included 17 patients tested preoperatively with socket-suspended prostheses and after 2 yr with OI prostheses and a control group (n = 17) using socket-suspended prostheses, evaluated once. Assessments on the prosthetic and intact feet were conducted at six frequencies (8, 16, 32, 64, 125, and 250 Hz). Furthermore, measurements were conducted to investigate how vibrometric signals are transmitted through a test prosthesis. The results showed that the OI group had improved ability to detect vibrations through the prosthesis at 125 Hz (p = 0.01) at follow-up compared with the preoperative measurement. Compared with the control group, the OI group at follow-up had better ability to detect high frequency vibrations through the prosthesis (125 Hz, p = 0.02; 250 Hz, p = 0.03). The vibrometric signal transmitted through the test prosthesis was reduced at 8, 125, and 250 Hz but was amplified at 16, 32, and 64 Hz. Differences between the OI and the control groups were found in the highest frequencies in which the test prosthesis showed reduction of the vibrometric signal. The study provides insight into the mechanisms of vibration transmission between the exterior and bone-anchored as well as socket-suspended amputation prostheses.

Load-Relief of Walking Aids on Osseointegrated Fixation: Instrument for Evidence-Based Practice

Clinicians are currently in demand of tools enabling individual assessment during their daily practice of load-relief of walking aids. The first aim of this article is to describe a portable kinetic system that could be used to measure directly the true load applied on the residuum during assisted walking. The second aim is to present the information that can be derived from the raw loading data. The third aim is to provide an example for a participant. One active transfemoral amputee fitted with an osseointegrated fixation was asked to walk in straight level line with no aid, one stick, one and two elbow crutches on a 20 m walkway. The load-relief was measured using a six-channel transducer and recorded using a data logger. The overall loading was decreased by 2% using one stick, 5% using one crutch and by 10% using two crutches. This study presents a method that can be used by clinicians facing the challenge of prescribing and assessing walking aids to restore the locomotion of lower limb amputees in the framework of an evidence-based practice.

Physiological cost index (PCI) and walking performance in individuals with transfemoral prostheses compared to healthy controls.

Purpose. Uncomplicated methods for evaluation of prosthetic walking performance for individuals with lower limb amputations are valuable. The Physiological Cost Index (PCI), the comfortable walking speed (CWS) and self-reported walking distances are three examples of such measures. The aim was to obtain values for these measures for individuals walking with transfemoral prostheses and to compare the results with healthy controls. Method. Individuals with an established transfemoral amputation for reasons other than vascular disease (TFA-group, n = 41, 30 male/11 female, mean age 49, SD 11.5) were compared to age-and gender matched healthy controls (Healthy group, n = 22). PCI was assessed walking in CWS for 5 min and self-reported distances accomplished outdoors was assessed with the Walking Habit Score (0 – 100). Results. Mean PCI was 0.55 (SD 0.19) in the TFA-group and 0.31 (SD 0.09) in the Healthy group (p < 0.001). The CWS was 62 (SD 12.6) and 90 (SD 12.8) m/min and the Walking Habit Score 48 (SD 19) and 74 (SD 16) score-points respectively (p < 0.001). Conclusions. By using uncomplicated and inexpensive methods, this study shows that walking with transfemoral prostheses is done with considerably increased energy cost, slower CWS and that limited walking distances outdoors are performed compared to healthy controls.

Osseoperception and Osseointegrated Prosthetic Limbs

During the last decade, bone anchorage of prosthetic limbs has become a realistic alternative to socket prostheses for patients with amputations due to causes other than severe peripheral vascular disease. The theoretical advantages that could be assumed to exist with an artificial limb attached to the bone as an extension of the residual skeleton, were first described more than 20 years ago (1) and could be summarized as follows: a stable attachment of the prosthetic device with elimination of any movements of a socket, better proprioception due to the stable attachment directly to the bone; elimination of skin and pain problems related to a prosthetic socket; and a better potential to control the prosthetic limb. However, it is through recent clinical research that these advantages have become a reality for patients. The first successful clinical applications of patients treated with bone-anchored amputation prostheses was by the use of the method of osseointegration (2). The discovery that implants made of commercially pure titanium could provide a stable anchorage for an implant in bone tissue was made by the Swedish Professor Per-Ingvar Branemark, during the 1950s. This phenomenon was later named osseointegration (3). Since 1965 the method of osseointegration has been in successful clinical practice for dental applications (4,5) and to date there have been more than two million patients who have been treated with dental implants due to edentulousness worldwide. Currently the same method is, for example, also used for treatment with bone-anchored hearing aids, for anchorage of prostheses due to other defects in the head and neck area (6), for finger joint prostheses (7,8), and for thumb amputation prostheses (9). Treatment with an osseointegrated (OI) transfemoral amputation prosthesis was performed for the very first time in 1990 in Sweden (2). Since then, the treatment has continued to be performed in Sweden and more recently also in the United Kingdom (10,11). Until today, most patients treated have had a transfemoral amputation, but individuals with amputations on the upper extremity, that is, transhumeral, transradial, and thumb amputations, have also been treated with OI prostheses. To date, more than 120 patients have been treated with OI prostheses worldwide, with most patients treated at the Sahlgrenska University Hospital in Gothenburg, Sweden. The treatment includes two surgical sessions. At the first surgery (S1), a titanium implant (fixture) is inserted in the residual bone and left unloaded for 3 to 6 months. At the second surgery (S2), a titanium rod (abutment) is inserted into the distal end of the fixture and then penetrates out of the skin on the residual limb (Fig. 10.1). Prosthetic suspension is obtained by connecting the OI prosthesis to the abutment with a specific attachment device (Figs. 10.2 and 10.3). After the second surgery, the patient undergoes a period of rehabilitation. For

Comparison of prosthetic costs and service between osseointegrated and conventional suspended transfemoral prostheses

Background: Nowadays, a transfemoral amputation prosthesis can be fitted to the skeleton using an osseointegrated implant, that is, without a socket. Treated patients have reported improvements in quality of life. Objectives: To investigate differences in prosthetic costs and service of osseointegrated prostheses compared to socket-suspended prostheses. Study Design: Retrospective cost analysis and survey. Methods: Costs and noted visits during in mean ~10 years were taken from one prosthetic workshop and included 50 patients with unilateral transfemoral amputation (36 socket-suspended prostheses, 20 osseointegrated prostheses, 6 patients used both kinds of prostheses). A survey comprised 71 patients (69% males; mean age = 52.3 year; cause: 66% trauma, 23% tumour, 11% other). Results: Statistically significant fewer workshop visits were shown with osseointegrated prostheses compared to socket-suspended prostheses (cost analysis: 3.1 vs. 7.2 visits/year, survey: 3.4 vs. 9.2 visits/year). The mean total annual cost of new prostheses, services, repairs and adjustments was 14% lower for osseointegrated prostheses than socket-suspended prostheses (€3149 and €3672 respectively, p = 0.632). A subgroup analysis of recent produced prostheses revealed cost of material to account for 92.5% for osseointegrated prostheses and 70% for socket-suspended prostheses. Conclusion: Despite significantly fewer visits for prosthetic service the annual mean costs for osseointegrated prostheses were comparable with socket-suspended prostheses. This study suggests it is due to more advanced prosthetic components being used with osseointegrated prostheses. Clinical relevance Patients with osseointegrated transfemoral prostheses require fewer visits for prosthetic service than patients with socket-suspended prostheses. The total prosthetic cost does not seem to differ between the two kinds of prostheses. However, more sophisticated prosthetic knees were more frequently used with osseointegrated prostheses, which could explain the lack of differences.

Load applied on bone-anchored transfemoral prosthesis: characterization of a prosthesis-a pilot study.

The objectives of this study were to (1) record the inner-prosthesis loading during activities of daily living (ADLs), (2) present a set of variables comparing loading data, and (3) provide an example of characterization of two prostheses. The load was measured at 200 Hz using a multi-axial transducer mounted between the residuum and the knee of an individual with unilateral transfemoral amputation fitted with a bone-anchored prosthesis. The load was measured while using two different prosthetic knees, mechanical (PRO1) and micro processor-controlled (PRO2), during six ADLs. The characterization of the prostheses was achieved using a set of variables split into four categories, including temporal characteristics, maximum loading, loading slopes, and impulse. Approximately 360 gait cycles were analyzed for each prosthesis. PRO1 showed a cadence improved by 19% and 7%, a maximum force on the long axis reduced by 11% and 19%, and an impulse reduced by 32% and 15% during descent of incline and stairs compared with PRO2, respectively. This work confirmed that the proposed apparatus and characterization can reveal how changes of prosthetic components are translated into inner-prosthetic loading.

Activités quotidiennes d’un amputé transfémoral équipé d’une fixation ostéo-intégrée : enregistrement continu des efforts pour une pratique fondée sur des preuves

Resume Les buts de cette etude sont de fournir a) une description detaillee de l’enregistrement continu du regime de la mise en charge de la prothese des amputes transfemoraux equipes d’une fixation osteo-integree durant les activites de la vie quotidienne et b) un cadre conceptuel d’analyse base sur les caracteristiques intrinseques des efforts mesures. Les forces et les moments appliques sur la fixation sont mesures et enregistres directement pendant cinq heures de la vie quotidienne par un capteur d’efforts connecte a un enregistreur de donnees. Cette etude montre que l’enregistrement peut etre divise en quatre activites comprenant la locomotion directionnelle, la deambulation reduite, les efforts stationnaires et l’inactivite representant respectivement 51 %, 25 %, 14 % et 10 % du total de l’impulsion. De plus, cette etude demontre que, dans le cas presente, seulement 50 % des efforts durant les periodes d’activites auraient pu etre estimes par les techniques conventionnelles. Cette technique a le potentiel d’etre largement utilisee par les cliniciens et les ingenieurs dans le cadre d’une pratique fondee sur des preuves.