Introduction to Upper Limb Prosthetics
Prosthetic arms can be inert, body-powered or bionic. The inert type of prosthetic arm is not activated and therefore serves a cosmetic function only. A body-powered prosthesis uses existing body motion to activate a movement device. The most common form of body-powered upper limb prosthetic is the shoulder harness which is used to activate the arm or hand.
Myobock® Below Elbow Prosthesis
Roger Wolfson and Associates is certified to provide the Myobock® Below Elbow upper limb prosthetic.
The Myobock® Below Elbow is a myo-electrically controlled upper limb prosthesis that includes accessories and fittings to ensure the most dependable rehabilitation results. The components of the Myobock® Below Elbow prosthesis combine optimal outer appearance with high grip force and grip speed, as well as numerous other combination and adjustment options.
DynamicArm Transhumeral Prosthesis
Amputations above the elbow constitute a special challenge since the function of the elbow has to be replaced in addition to that of the hand. The DynamicArm elbow joint makes virtually natural movements possible with its special technology. Controlled by your muscle signals, the DynamicArm is driven by an electric motor. The control unit of the DynamicArm also transmits the muscle signals to the prosthetic hand, so that you are able to rotate the wrist unit in addition to opening and closing the hand with short response times. You can extend and flex the DynamicArm as well.
We recommend combining the DynamicArm with the Ottobock VariPlus Speed. It is equipped with a high-performance drive unit, and opens and closes almost three times as fast as other electric hands. A fitting with the DynamicArm and VariPlus Speed restores numerous abilities to hold objects, grasp and be active at work, in everyday life and recreation.
The Residual Limb
There are three major critical factors involved in the design and optimisation of trans humeral and elbow disarticulation prosthetics, including:
- Length of the bony lever arm
- Quality and nature of soft tissue coverage
- Shape and muscle tone of the residual limb
The above-elbow prosthesis consists of:
- A single plastic upper arm shell
- An elbow joint, usually with incorporated locking mechanism
- A plastic forearm
- A wrist joint
- A terminal device, either a hook or a hand.
A body-powered elbow unit consists of a simple hinge, with a half-dome-shaped plastic covering. To retain an elbow position two options are available, which take the form of either a friction or a locking mechanism. Such devices that function as locking mechanisms are operated using a knob located on the forearm or using a cable attached to the shoulder harness. To assist the user of a body-powered above elbow prosthesis in flexing the elbow, an elbow unit with a forearm lift assist is used, which acts as a spring mechanism that somewhat compensates for gravitational forces.
A wrist unit is used for:
- Attaching purposes
- Rotation purposes (passively with sound hand)
- Interchange between hands/hooks.
The function of the terminal device is to replace the grasp function of the hand.
Three types of terminal device are available:
- To grasp small objects
- To grasp, hold, carry, pull or push.
- To grasp large, round objects
- To grasp between thumb and first two fingers (three jaw chuck pattern)
- Entire passive, for cosmetic purposes only
As the term suggests, a body-powered prosthesis uses the patient’s own body power to activate motion of the artificial limb. Thus, where it concerns upper limb prosthetics, the body harness is a necessary and extremely important component. The harness transfers motion and forces from the residual limb, shoulder girdle and trunk directly to the prosthesis. In cases where there is a loss of an elbow, the harness is also fixed to the socket above the elbow stump. The higher the amputation level, the more difficult it becomes to control and fix the prosthesis. Nevertheless, a patient with a shoulder level amputation can still be fitted with a prosthetic.
A body harness can also be used to control elbow flexion and locking. In the case of a below elbow fitting, the harness activates the terminal device only.
A body-powered prosthesis together with natural muscle motion enables good functionality. The pressure of the harness on the body also gives the patient sensory feedback. However, the degree of sensory feedback depends on the fit of the prosthetic socket, the harness as well as the features of the prosthetic hand.
When fitting a body harness, no two people are the same. Hence, the fitting must be performed on an individual basis. Two patients with the same physical constitution may be different with respect to the motion and force in the shoulder girdle region as well as each residual limb is different.
To accommodate an above elbow prosthesis, two very different harness systems have been developed and proven in practice, enabling performance of the required functions consisting of activating the terminal device, below elbow flexing and independent locking or releasing of the elbow joint.
Basic functions of the harness system
The main function of the harness is to suspend the prosthesis to the residual limb. In so doing it should:
- Distribute load as much as possible
- Be well suited to the patient’s body structure
- Be stable in all normal positions of use
Upper limb prosthetic rehabilitation
Follow up consultation sessions are the most important aspect of the upper limb prosthetic rehabilitation process. Yet, most often, this process is neglected. There are three important aspects to consider following the initial prosthetic fitting:
- Maintenance of the socket fit, suspension and comfort of the patient, especially where this pertains to volume changes in the residual limb.
- Ongoing monitoring to ensure that the patient fully masters the functions of the prosthesis at home as well as in the work environment.
- Re-evaluation of socket style, harness design and component selection based on the experience of the individual.
There are numerous aspects to upper limb prosthetic rehabilitation that cannot be addressed until the patient has had a reasonable amount of time to assimilate the use of the new prosthetic. Questions need to be answered and new skills need to be mastered. In line with goals and aspirations, the fit, comfort and function of the prosthesis need to be maintained and optimized over time.
Successful long term use of an upper limb prosthesis depends primarily on its comfort and perceived value. Innovative design and careful custom adaptation of socket and harness principles, careful attention to follow up adjustments and prescription revisions based on changing needs are essential to successful prosthetic rehabilitation.
From surgery to rehabilitation to the fitting of your prosthesis – The journey: part 2 – Learning about prosthetic limbs and their technicalities
Modern prosthetics work so effectively nowadays and look so convincing that often, you may not be able to detect that one is being worn. Those with prosthetic legs can often walk, run and even swim as though they were using natural limbs. Nowadays, prosthetic technologies are available that enable the wearer of prosthetic arm and hands to have individual control of all five fingers.
Prosthetic limbs rank high among the world’s greatest inventions and provide a great boosting in terms of optimism and independence – key factors in dramatically improving quality of life.
What do prosthetics involve?
Prosthetics, also known as artificial limbs, are an artificially constructed substitute for a limb that could have been lost through either a congenital condition which is present at birth, illness, wartime injury or accident.
A cosmesis has little function and is worn for prosthetic reasons
A type of prosthetic known as a cosmesis is designed purely for cosmetic reasons and has little or no function. Artificial hands often fall into this category.
Other prosthetics are highly functional and have little or no cosmetic value, which artificial legs designed to be covered by trousers are a typical example and are often little more than metal rods and wires.
Types of prostheses
Any part of the body, from the ear or nose to the finger or toe could be replaced by a prosthesis in theory. However, in practice there are four common types of prosthetic limbs that are designed to replace either a partial or complete loss of an arm or leg.
- A below the knee, also known as a BK or transtibial prosthetic consists of a prosthetic lower leg which is attached to an intact upper leg.
- An above the knee, also known as a AK or tranfemoral prosthetic consists of a prosthetic lower and upper leg which includes a prosthetic knee,
- A below the elbow, also known as a BE or transradial prosthetic consists of a prosthetic forearm.
- An above the elbow, also known as a transhunmeral prosthetic consists of a prosthetic lower and upper arm which includes a prosthetic elbow.
- Above the knee (AK, transfemoral): A prosthetic lower and upper leg, including a prosthetic knee.
- Below the elbow (BE, transradial): A prosthetic forearm.
- Above the elbow (AE, transhumeral): A prosthetic lower and upper arm, including a prosthetic elbow.
At Roger Wolfson and Associates we firmly believe that the more you know about what goes on behind the scenes with prosthetics, the better equipped you will be to get the best out of your new limb. Give Roger a call on (011) 640 7198 and send an email to email@example.com.
From surgery to rehabilitation to the fitting of your prosthesis – the journey: part 1
The aim of this two-part article is to offer a concise overview of your journey towards your ultimate goal of a successful prosthetic outcome – that is, to restore your mobility.
So that you can lead an active and normal life, your therapy team, which includes doctors, therapists your prosthetist and not to mention you and your loved ones, will all band together to help you achieve independence.
An average indication is that the rehabilitation process can take anything from two to six months. The length of time this process takes can vary considerably taking various factors into account such as how well your prosthesis fits and your own levels of motivation.
The information that follows outlines a number of helpful suggestions to aid your rehabilitation and recovery. However, it should be borne in mind that the instructions you receive from those on your rehabilitation team should take priority since it is those individuals who are best qualified to evaluate your individual situation.
Whether you have recently found out about your amputation or have known for a length of time, it is important to always remember that you are not alone. Your physicians are there to offer support, answer your questions and find you the solutions that will work best for you.
Pre-surgical examinations and discussions
If you are to undergo a planned amputation surgical procedure, you will be examined several times in great detail prior to surgery. Your doctors will explain what takes place during surgery and what will take place after the operation has been performed.
In the case of a traumatic accident, such conversations will happen post-surgery.
You have the opportunity to ask any questions that are important to you during these discussions and it is a good idea to note down anything that you may wish to ask your doctor prior to these discussions. Always remember that it is the task of the physician to clearly explain things clearly.
Preparation in advance
Talk to your prosthetist about the types of prostheses available and what is best suited to you
It is of critical importance that you talk to your prosthetist about the types of prostheses available and what is best suited to you in terms of your lifestyle needs.
If at all possible, it is a good idea to begin therapy exercises that you will use after the amputation surgery before your surgery takes place. This will enable you to strengthen your muscles in advance. It is also a good idea to practice moving properly from the bed to the wheelchair. This advance preparation can make the time after the operation a lot easier on you. Of course, your medical team are there to guide when it comes to the exercises most suitable for you.
Counselling and psychological support
Undergoing an amputation represents a big change in your life and it is always helpful to seek counselling and psychological support which can greatly assist you in working through any issues or fears you may have, while taking the weight off of yourself as well as your friends and family.
Engaging with other amputees
We strongly recommend that you engaging with other amputees who have also undergone amputation surgery. Others will offer their opinions and advice and will be able to share tips on everything to do with using your new prosthesis.
At Roger Wolfson and Associates we are here to answer your questions and put you in touch with those that offer support in numerous ways. Call us on (011) 640 7198 or drop Roger a mail at firstname.lastname@example.org.
3 important questions you should ask prior to undergoing a lower limb amputation
Statistics show that for every 1000 people in South Africa there are approximately 1.5 amputees.
The main reasons behind why and how amputations occur include:
- Vascular disease which covers diabetes and peripheral arterial diseases
In this article we address three important questions you should consider prior to undergoing a lower limb amputation which can be either below the knee (trans tibial) or above the knee (trans femoral).
- At one point should I consult with a prosthetist?
To ensure optimal prosthetic outcomes, it is critical that you consult with a prosthetist prior to undergoing surgery.
The process begins with an overall evaluation of your mobility and lifestyle expectations as well as an analysis of the various details involved in your condition as well as the nature of the upcoming surgery.
A number of surgeons see this process as invaluable especially in determining whether certain surgical techniques should be used that could enhance desired outcomes post-surgery.
Detailed knowledge and understanding of the specifics involved in your situation greatly assist the prosthetist to fabricate and fit a prosthetic that will work best for you.
- How do I prepare for the initial prosthesis fitting
The time it takes before a prosthesis can be worn varies from person to person, and can also depend upon the nature of the surgery as well as your own unique circumstances and can even be influenced by surgical techniques such as Immediate Post-Prosthesis (IPOP).
Your surgeon, your prosthetist and your physical therapist all play very important roles in your rehabilitation. Your residual limb is bandaged and treated immediately post-surgery in order for your surgical wound to effectively heal. It is crucial that you follow the recommendations of all professionals involved in your recovery.
Taking the appropriate time to heal and wear compression stockings to decrease the swelling are both key factors in preparing you for your initial prosthesis fitting.
- What takes place during physical therapy in the prosthesis fitting process?
Post-operative physical therapy ensures that you retain the function of your residual limb and prepare the area for your temporary and then your definitive prosthesis. Physical therapy is important in maintaining and expanding mobility and activity levels during the prosthesis fitting process.
Maintaining a positive mental attitude is vital to successful recovery
The role of maintaining a positive mental attitude cannot be underestimated in successful recovery and it is not uncommon for a patient to discover that they have greater mobility once accustomed to a new prosthesis as opposed to living with an unhealthy limb prior to surgery.
If you would like to know more about what to do prior to undergoing surgery for an amputation or need to ask Roger a question call us on (011) 640 7198 or drop us an email at email@example.com.
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