Benefits of the Genium microprocessor controlled prosthetic knee on ambulation, mobility, activities of daily living and quality of life: a systematic literature review.

PURPOSE: The benefits of advanced hydraulic microprocessor controlled knee (MPK) joints have been well established and repeatedly confirmed. The Genium knee was introduced in 2011 containing an enhanced control concept including additional sensors and improved algorithms enabling a range of new functions for transfemoral amputees (TFAs). A systematic review was conducted to evaluate the effect of the Genium knee on ambulation, mobility, activities of daily living (ADLs) and quality of life compared to standard MPKs. MATERIALS AND METHODS: The review was conducted according to PRISMA Guidelines and Recommendations of the State-of-Science Evidence Report Guidelines of the American Academy of Orthotists & Prosthetists. RESULTS: Twelve articles were included in the review and reported primarily on active subjects (MFCL-3/4) transitioning from C-Leg to Genium knee systems. The overall validity of the evidence was medium to high with the exception of one article having low validity. Synthesis of biomechanical analyses concludes that gait during level walking, stairs and ramps is more physiological and symmetric following accommodation and use of the Genium in community ambulating TFAs. Further, sound side loading and compensatory motions are reduced. Transitioning from C-Leg to the Genium knee additionally resulted in significant improvements in mobility, quality of life and the performance in activities of daily living (ADLs). CONCLUSION: A high level of evidence was identified when assessing the ability of Genium to improve gait quality and safety and performance in ADLs. While individual studies report significant improvements in terms of quality of life and mobility, additional studies are needed to increase the evidence level.Implications for rehabilitationMicroprocessor controlled prosthetic knees (MPKs) are well-established devices to serve patients with transfemoral amputation. Studies conducted mostly with the C-Leg MPK show that such knees significantly increase patient safety, ambulation, mobility, performance in activities of daily living and quality of life.Genium MPK includes advanced features which enable a range of new functions and functional benefits to patients. Transitioning from conventional MPKs (i.e., C-Leg) to Genium MPK resulted in more physiological gait, more equally distributed loading between the prosthetic and sound limbs, as well as reduced compensatory movements on the sounds side. These outcomes could potentially reduce the long-term risks of secondary physical complications in prosthetic users (i.e., osteoarthritis, osteoporosis). Genium significantly improved mobility, performance in activities of daily living, and quality of life in the patients using a conventional MPK (C-Leg).Different functioning principles of the MPKs presently available are responsible for different performance levels the knees offer to users. The amount of clinical evidence is also knee-dependent, with the C-Leg knee being most extensively tested in clinical studies. This systematic review concludes that Genium offers further advantages to transfemoral patients as compared to conventional MPKs (C-Leg).

First results concerning the safety, walking, and satisfaction with an innovative, microprocessor-controlled four-axes prosthetic foot.

BACKGROUND: The microprocessor-controlled foot Meridium is a prosthetic component with adjustable stance-phase characteristics. OBJECTIVES: To investigate subjects' and prosthetists' perception of safety, walking, and satisfaction during first routine fittings. STUDY DESIGN: Multicenter, prospective, observational cohort study. METHODS: Data regarding demographics, fitting process, safety, daily life activities, and satisfaction were obtained through questionnaires. The follow-up period was 7 months. RESULTS: In all, 89% of 70 users were satisfactorily fitted within the first two visits. Compared to previous feet, users reported improvements in walking on level ground (54% of subjects), uneven ground (82%), ascending (97%), and descending ramps (91%). More than 45% of the users perceived an improvement in safety and stability while standing and walking. No difference was observed in concentration, exertion, and pain. Overall user satisfaction with Meridium was 50% and the foot was preferred by 40% of users. Amputation level, age and mobility grade did not influence subjects' preference. Prosthetists recommended Meridium for 59% of subjects. A correlation analysis revealed that transfemoral amputees fitted with Genium and/or having a long residual limb strongly preferred Meridium ( p < 0.05). CONCLUSION: Meridium was appreciated by amputees with a preference for natural walking and requirement to safely and comfortably negotiate uneven terrain and slopes. Clinical relevance Amputees preferring Meridium perceive benefits with safe, comfortable, and natural walking. While the perception of benefits regarding the negotiation of uneven terrain and slopes is very high, the correlation to product preference is moderate. Individual assessment and trial fitting might be essential to identify patients who benefit greatly.

Mathematical models of proprioceptors. II. Structure and function of the Golgi tendon organ.

We developed a physiologically realistic mathematical model of the Golgi tendon organ (GTO) whose elements correspond to anatomical features of the biological receptor. The mechanical interactions of these elements enable it to capture all salient aspects of GTO afferent behavior reported in the literature. The model accurately describes the GTO's static and dynamic responses to activation of single motor units whose muscle fibers insert into the GTO, including the different static and dynamic sensitivities that exist for different types of muscle fibers (S, FR, and FF). Furthermore, it captures the phenomena of self- and cross-adaptation wherein the GTO dynamic response during motor unit activation is reduced by prior activation of the same or a different motor unit, respectively. The model demonstrates various degrees of nonlinear summation of GTO responses resulting from simultaneous activation of multiple motor units. Similarly to the biological GTO, the model suggests that the activation of every additional motor unit to already active motor units that influence the receptor will have a progressively weaker incremental effect on the GTO afferent activity. Finally, the proportional relationship between the cross-adaptation and summation recorded for various pairs of motor units was captured by the model, but only by incorporating a particular type of occlusion between multiple transduction regions that were previously suggested. This occlusion mechanism is consistent with the anatomy of the afferent innervation and its arrangement with respect to the collagen strands inserting into the GTO.

Mathematical models of proprioceptors. I. Control and transduction in the muscle spindle.

We constructed a physiologically realistic model of a lower-limb, mammalian muscle spindle composed of mathematical elements closely related to the anatomical components found in the biological spindle. The spindle model incorporates three nonlinear intrafusal fiber models (bag(1), bag(2), and chain) that contribute variously to action potential generation of primary and secondary afferents. A single set of model parameters was optimized on a number of data sets collected from feline soleus muscle, accounting accurately for afferent activity during a variety of ramp, triangular, and sinusoidal stretches. We also incorporated the different temporal properties of fusimotor activation as observed in the twitchlike chain fibers versus the toniclike bag fibers. The model captures the spindle's behavior both in the absence of fusimotor stimulation and during activation of static or dynamic fusimotor efferents. In the case of simultaneous static and dynamic fusimotor efferent stimulation, we demonstrated the importance of including the experimentally observed effect of partial occlusion. The model was validated against data that originated from the cat's medial gastrocnemius muscle and were different from the data used for the parameter determination purposes. The validation record included recently published experiments in which fusimotor efferent and spindle afferent activities were recorded simultaneously during decerebrate locomotion in the cat. This model will be useful in understanding the role of the muscle spindle and its fusimotor control during both natural and pathological motor behavior.