Rickard Brånemark

Consequences of non-vascular trans-femoral amputation: A survey of quality of life, prosthetic use and problems

Individuals with unilateral trans-femoral amputations due to non-vascular causes were studied in a mailed survey designed to investigate health-related quality of life (HRQL), prosthetic use and problems. The Swedish SF-36 Health Survey and a structured questionnaire designed for trans-femoral amputees were used. The series consisted of 97 subjects (60 men, 37 women), aged 20 to 69 years with a mean of 22 years since the amputation. Trauma was the cause of amputation in 55%, tumour in 35% and other causes in 10%. Ninety-two (92) subjects (95%) had a prosthesis and 80 (82%) used it daily. General HRQL was significantly lower than Swedish age- and gender-matched norms in all dimensions as measured by SF-36. Most frequently reported problems that had led to reduction in quality of life were heat/sweating in the prosthetic socket (72%), sores/skin irritation from the socket (62%), inability to walk in woods and fields (61%) and inability to walk quickly (59%). Close to half were troubled by stump pain (51%), phantom limb pain (48%), back pain (47%) and pain in the other leg (46%). One fourth considered themselves to have a poor or extremely poor overall situation. Trans-femoral amputation, due to non-vascular causes, has an evident impact on quality of life and there are considerable problems related to the amputation and the prosthesis. Efforts to improve the physical and the psychological well-being for this group, with a long life expectancy, are needed.

Biomechanical characterization of osseointegration during healing: an experimental in vivo study in the rat

This study reports torsion tests and pull-out tests on osseointegrated commercially pure titanium fixtures. The tests were performed in vivo on a total of 26 rats. Three fixtures with a diameter of 2.0 mm were installed bilaterally in the proximal tibia in each animal. The mechanical testing was performed immediately after installation, after 2, 4, 8 and 16 weeks of unloaded healing. The torsional strength started to increase after 4 weeks of unloaded healing and there was a significant increase with time during the initial 16 weeks. The pull-out load increased rapidly during the first 4 weeks; thereafter, a moderate increase occurred during the following 12 weeks. A histological evaluation was performed after 0, 4, 8 and 16 weeks. There were significant (P < 0.01) correlations between torque and percentage of bone in contact with the fixture, and between pull-out load and the bone thickness around the fixture (P < 0.001). Estimations of shear stresses and shear moduli in the bone tissue (pull-out test) and at the interface (torque test) indicated that the increase in bone volume around the implant substantially improved the mechanical capacity.

Osseointegrated trans-femoral amputation prostheses: Prospective results of general and condition-specific quality of life in 18 patients at 2-year follow-up

This is the first report on prospective outcome for individuals treated with bone-anchored trans-femoral amputation prostheses (OI-prostheses) using the method of osseointegration. The aim was to analyze general and condition-specific health related quality of life (HRQL) at 2-year follow-up as compared to the preoperative situation. The study population consists of the first 18 consecutively treated patients (8 male/10 female, mean age 45 years) in a clinical investigation with amputations mainly caused by trauma and tumour. At inclusion the mean time since the amputation was 15 years (10 months – 33 years). Two self-report questionnaires were answered preoperatively and at follow-up: the SF-36 Health Survey (SF-36) and the Questionnaire for persons with a Transfemoral Amputation (Q-TFA). At follow-up 17/18 patients used the OI-prosthesis; one did not due to pain and loosening of the implant. Four of the scales of the SF-36 (Physical Functioning, Role Functioning Physical, Bodily Pain and Physical Component Score) and all four scores of Q-TFA (Prosthetic Use, Prosthetic Mobility, Problems and Global Health) were statistically significantly improved at follow-up showing superior general physical HRQL, increased prosthetic use, better prosthetic mobility, fewer problems and a better global amputation situation. Thus, osseointegrated prostheses represent a promising development in the rehabilitation of individuals with transfemoral amputation and increase their quality of life.

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.

An osseointegrated human-machine gateway for long-term sensory feedback and motor control of artificial limbs

An osseointegrated interface allowed long-term stable and bidirectional communication between robotic prostheses and implanted neuromuscular electrodes for intuitive control with sensory feedback in one patient. A Bone-Anchored Arm Prosthetic An artificial limb should not only anatomically resemble its original counterpart but also function and feel just like it. Currently available prosthetic limbs allow for basic functions—closing a door or taking a step—but they often do not support fine-motor control or sensory perception. Ortiz-Catalan and coauthors describe a first-in-human trial of a bone-anchored (osseointegrated) upper-arm prosthetic that attached directly to the bone, nerves, and muscles of the remaining limb. The patient was followed for 1 year, demonstrating finer motor control (grasping, for example, an egg without breaking it) and a greater range of motion (touching toes and reaching arm overhead) compared with a conventional socket prosthesis with surface electrodes. Direct electrical stimulation of the peripheral nerves also provided the patient a sense of touch. The study was in only one patient, thus preventing quantification of improvement, which may vary depending on the amount of soft tissue and scar tissue remaining in the stump. Nevertheless, osseointegration could revolutionize the field of neuroprosthetics, giving patients more intuitive control and more freedom of movement. A major challenge since the invention of implantable devices has been a reliable and long-term stable transcutaneous communication. In the case of prosthetic limbs, existing neuromuscular interfaces have been unable to address this challenge and provide direct and intuitive neural control. Although prosthetic hardware and decoding algorithms are readily available, there is still a lack of appropriate and stable physiological signals for controlling the devices. We developed a percutaneous osseointegrated (bone-anchored) interface that allows for permanent and unlimited bidirectional communication with the human body. With this interface, an artificial limb can be chronically driven by implanted electrodes in the peripheral nerves and muscles of an amputee, outside of controlled environments and during activities of daily living, thus reducing disability and improving quality of life. We demonstrate in one subject, for more than 1 year, that implanted electrodes provide a more precise and reliable control than surface electrodes, regardless of limb position and environmental conditions, and with less effort. Furthermore, long-term stable myoelectric pattern recognition and appropriate sensory feedback elicited via neurostimulation was demonstrated. The opportunity to chronically record and stimulate the neuromuscular system allows for the implementation of intuitive control and naturally perceived sensory feedback, as well as opportunities for the prediction of complex limb motions and better understanding of sensory perception. The permanent bidirectional interface presented here is a critical step toward more natural limb replacement, by combining stable attachment with permanent and reliable human-machine communication.

Questionnaire for Persons with a Transfemoral Amputation (Q-TFA): initial validity and reliability of a new outcome measure.

The Questionnaire for Persons with a Transfemoral Amputation (Q-TFA) is a new self-report measure developed for nonelderly transfemoral amputees using a socket- or osseointegrated prosthesis to reflect use, mobility, problems, and global health, each in a separate score (0-100). This paper describes the initial measurement properties of the Q-TFA as completed by 156 persons with a transfemoral amputation using a socket prosthesis (67% male, 92% nonvascular cases, mean age 51 years). Criterion validity was determined by associations between scores of the Q-TFA and the Short-Form 36 (SF-36)-Item Health Survey. Reliability was assessed by retest (n = 48) and by determination of the internal consistency. Correlations between Q-TFA and SF-36-Item Health Survey scales matched hypothesized patterns. Intraclass correlations were between 0.89 and 0.97, and measurement error ranged from 10 to 19 points. Cronbachs alpha revealed good internal consistency, with no values less than 0.7. This study shows that the Q-TFA, applied to persons using a transfemoral socket prosthesis, has adequate initial validity and reliability.

Characterization of the surface properties of commercially available dental implants using scanning electron microscopy, focused ion beam, and high-resolution transmission electron microscopy

BACKGROUND Since osseointegration of the respective implant is claimed by all manufacturing companies, it is obvious that not just one specific surface profile including the chemistry controls bone apposition. PURPOSE The purpose was to identify and separate out a particular set of surface features of the implant surfaces that can contribute as factors in the osseointegration process. MATERIAL AND METHODS The surface properties of several commercially available dental implants were extensively studied using profilometry, scanning electron microscopy, and transmission electron microscopy. Ultrathin sections prepared with focused ion beam microscopy (FIB) provided microstructural and chemical data which have not previously been communicated. The implants were the Nobel Biocare TiUnite (Nobel Biocare AB, Göteborg, Sweden), Nobel Biocare Steri-Oss HA-coated (Nobel Biocare AB, Yorba Linda, CA, USA), Astra-Tech OsseoSpeed (Astra Tech AB, Mölndal, Sweden), Straumann SLA (Straumann AG, Waldenburg, Switzerland), and the Brånemark Integration Original Fixture implant (Brånemark Integration, Göteborg, Sweden). RESULTS It was found that their surface properties had differences. The surfaces were covered with crystalline TiO(2) (both anatase and rutile), amorphous titanium oxide, phosphorus doped amorphous titanium oxide, fluorine, titanium hydride, and hydroxyapatite, respectively. CONCLUSION This indicates that the provision of osseointegration is not exclusively linked to a particular set of surface features if the implant surface character is a major factor in that process. The studied methodology provides an effective tool to also analyze the interface between implant and surrounding bone. This would be a natural next step in understanding the ultrastructure of the interface between bone and implants.

Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient

A variety of treatments have been historically used to alleviate phantom limb pain (PLP) with varying efficacy. Recently, virtual reality (VR) has been employed as a more sophisticated mirror therapy. Despite the advantages of VR over a conventional mirror, this approach has retained the use of the contralateral limb and is therefore restricted to unilateral amputees. Moreover, this strategy disregards the actual effort made by the patient to produce phantom motions. In this work, we investigate a treatment in which the virtual limb responds directly to myoelectric activity at the stump, while the illusion of a restored limb is enhanced through augmented reality (AR). Further, phantom motions are facilitated and encouraged through gaming. The proposed set of technologies was administered to a chronic PLP patient who has shown resistance to a variety of treatments (including mirror therapy) for 48 years. Individual and simultaneous phantom movements were predicted using myoelectric pattern recognition and were then used as input for VR and AR environments, as well as for a racing game. The sustained level of pain reported by the patient was gradually reduced to complete pain-free periods. The phantom posture initially reported as a strongly closed fist was gradually relaxed, interestingly resembling the neutral posture displayed by the virtual limb. The patient acquired the ability to freely move his phantom limb, and a telescopic effect was observed where the position of the phantom hand was restored to the anatomically correct distance. More importantly, the effect of the interventions was positively and noticeably perceived by the patient and his relatives. Despite the limitation of a single case study, the successful results of the proposed system in a patient for whom other medical and non-medical treatments have been ineffective justifies and motivates further investigation in a wider study.

Bone response to laser-induced micro- and nano-size titanium surface features

UNLABELLED This study explored whether laser-induced, site-specific implant surface modifications with micro- and nano-scale topography were able to promote bone formation. The aim was to evaluate the biomechanical and histological response to partly laser-modified titanium implants in comparison with machined implants. After an early 8-week healing period in rabbit tibia and femur, a 250% increase in removal torque was demonstrated for the partly laser-modified surface. Further, different fracture mechanisms were demonstrated for the two surfaces. Histologically, significantly more bone was found in direct contact with the laser-modified surface for the implants in the tibia sites, and a similar amount of bone tissue was observed in contact with the implant in the femoral sites. In conclusion, an improved bone-implant interface anchorage was promoted by an increase in micro- and nano-scale implant surface topography and surface oxide induced by topological laser treatment. FROM THE CLINICAL EDITOR Nanosized grooves in titanium implants markedly improve bone-implant anchorage by increasing the amount of bone formed in direct contact with the metal prosthesis.

BioPatRec: A modular research platform for the control of artificial limbs based on pattern recognition algorithms

BackgroundProcessing and pattern recognition of myoelectric signals have been at the core of prosthetic control research in the last decade. Although most studies agree on reporting the accuracy of predicting predefined movements, there is a significant amount of study-dependent variables that make high-resolution inter-study comparison practically impossible. As an effort to provide a common research platform for the development and evaluation of algorithms in prosthetic control, we introduce BioPatRec as open source software. BioPatRec allows a seamless implementation of a variety of algorithms in the fields of (1) Signal processing; (2) Feature selection and extraction; (3) Pattern recognition; and, (4) Real-time control. Furthermore, since the platform is highly modular and customizable, researchers from different fields can seamlessly benchmark their algorithms by applying them in prosthetic control, without necessarily knowing how to obtain and process bioelectric signals, or how to produce and evaluate physically meaningful outputs.ResultsBioPatRec is demonstrated in this study by the implementation of a relatively new pattern recognition algorithm, namely Regulatory Feedback Networks (RFN). RFN produced comparable results to those of more sophisticated classifiers such as Linear Discriminant Analysis and Multi-Layer Perceptron. BioPatRec is released with these 3 fundamentally different classifiers, as well as all the necessary routines for the myoelectric control of a virtual hand; from data acquisition to real-time evaluations. All the required instructions for use and development are provided in the online project hosting platform, which includes issue tracking and an extensive “wiki”. This transparent implementation aims to facilitate collaboration and speed up utilization. Moreover, BioPatRec provides a publicly available repository of myoelectric signals that allow algorithms benchmarking on common data sets. This is particularly useful for researchers lacking of data acquisition hardware, or with limited access to patients.ConclusionsBioPatRec has been made openly and freely available with the hope to accelerate, through the community contributions, the development of better algorithms that can potentially improve the patient’s quality of life. It is currently used in 3 different continents and by researchers of different disciplines, thus proving to be a useful tool for development and collaboration.