NORMAL GAIT & BIOMECHANICS

NORMAL GAIT

•       It is the series of rhythmical, alternating movements of limb and trunk, which results in the forward progression of the center of gravity.

•       The gait cycle is the period of time between any two identical events in the walking cycle  e.g.: Time from heel strike to the next ipsilateral heel strike.  The gait cycle is divided into two periods

•       Stance Phase

o   It is the phase of gait cycle in which the foot is in contact with the ground and is bearing the body weight.

o   It is 60% of the total gait cycle.

•       Swing Phase

o   it is the phase of gait cycle in which the foot is not in contact with the ground and is not bearing the body weight.

o   It is 40% of the total gait cycle.

•       Step length

o   It is the linear distance in the plane of progression between corresponding successive contact points of opposite feet.

•       Stride length

o   It is the linear distance between the corresponding successive points of heel contact of the same foot.

•       Single support

o   It refers to the period when only one foot is in contact with floor.

•       Double support (20% of gait cycle)

o   It occurs when both feet are in contact with floor.

o   The absence of period of double support distinguishes running from walking.

•       Cadence

o   It is the number of steps taken per minute. It may vary from 70 in slow walking to 130 in fast walking,

o   Adult male covers 2.50 miles or 4 km in one hour.

 Sub divisions of stance phase

•       Heel contact

o   The instant when the heel of the reference limb touches the floor.

•       Ball contact

o   When the bases of the metatarsals of the reference limb’s foot touches the floor

•       Foot flat

o   The initial contact of the forefoot with the floor.

•       Mid stance

o   When the greater trochanter is in vertical alignment with the vertical bisector of foot.

•       Heel off

o   When the heel of the reference foot leaves the floor.

•       Toe off

o   When the toe of the reference foot leaves the floor.

OR

It can be divided into

•       Weight acceptance phase

o   begins at heel contact and ends with foot flat position.

•       Mid stance

o   Begins with foot flat and ends with heel off.

•       Push off

o   Extends from heel off to toe off.

•       Sub divisions of swing phase:

It can be divided in to:

•       Acceleration:

It is characterized by the rapid acceleration of the lower end of the limb shortly after the toe off.

•       Mid swing:

It is the interval when the swinging limb over takes and moves ahead of the limb in stance face (contra lateral limb).

•       Deceleration:

It is the interval when the swinging limb approaches the end of interval and slows down for heel contact.

 Path of center of gravity:

         The laws of mechanics make it clear that the least amount of energy is required when a body moves along straight lines, with center of gravity neither deviating neither up and down or side ways. Which is not possible in human beings?  So the body’s center of gravity deviates from straight line but for the sake of energy conservation, deviation should be kept to an optimal level. This is done by the muscles and ligaments of the body.

 Vertical displacement:

          In the normal walking pattern the center of gravity goes trough a rhythmical ups and downs as it moves forward but it is extremely smooth with no abrupt change in direction. The highest point is in the mid stance and the lowest point is in double support. The average amount of vertical displacement is 5cm or 2 inches.

Lateral displacement:

          As weight is transfers from one limb to the other one the pelvis also shifts to the weight bearing side and with it COG also shifts. The total amount of sideway movement of pelvis is 5cm or 2 inches. The limit is achieved in the mid stance and the path followed by the COG is extremely smooth.

Gait characteristics that influence the path of COG:

The characteristics that influence the path of COG are:

•       Flexion on knee during stance

Just after the heel contact, flexion of knee begins and continues until it reaches 20*. This characteristic of normal gait helps to smoothen the path of COG and limits it’s up and down osilation to an optimal level

•       Pelvic depth

In normal walking the pelvis drops on the swing side, i.e: stance hip adducts slightly. The amount of displacement of the pelvis from the horizontal is controlled with in 5* by the abductors of the hip of the contralateral side. In standing this dip found is the positive trendelenberg sign, in walking it is normal and serves to reduce the upward displacement of COG.

•       Pelvic rotation

In addition to the dipping the pelvic rotates forward in the horizontal plane. This rotation is 4* on each side of the COG. This helps to reduce the vertical displacement of COG.

•       Width of the walking base

In figure WB is the width of the walking base that falls within the range of 5-10cm or 2-4 inches. As the pelvic shifts towards the supporting side to maintain the stability so the normal narrow walking base minimizes the lateral shifting of the COG.

Parts of Transtibial Prosthesis

Transtibial prosthesis consist the following parts

•       Socket

•       Socket adopter

•       Shank

•       Foot adopter

•       Foot

Note: All the above mentioned components are discussed in detail.

Prosthetics sockets

•       Prosthetic socket connect the residual limb to the prosthesis.

•       It provides optimum support to the patient and ensures a good prosthesis fitting.

•       The prosthetic socket consists of a liner and a matching closure system.

•       The liner acts as a sort of “second skin” between the movable soft tissue of the residual limb (muscles, tissue, skin) and the hard shell of the socket.

•       It is custom–made according to the shape and condition of the residual limb and the respective mobility grade.

OBJECTIVES OF SOCKET

•       Total Contact.

•       Good sensory feed back.

•       Loading Pressure Tolerant Areas.

•       Relieving Pressure Sensitive Areas.

•       Light in Weight.

•       Cosmetically Acceptable.

•       Strong enough for weight bearing.

•       Suspend the prosthesis.

•       5-10° of socket flexion exposes more of the anterior wall for weight bearing.

PARTS OF SOCKET

•       Prosthetic socket consist of

o   Soft inliner(second skin)

o   Laminated socket 

SECOND SKIN

The “second skin” is

•       thin protective membrane

•       made of a flexible material

•       Rolled over the residual limb.

•       It connects the residual limb of patient to the socket.

•       Selection of right liner is essential so that prosthesis fits well and is comfortable to wear.

•       For optimum patient safety and comfort there should be a good combination of liner and closure system.

The single most critical aspect of any
prosthesis is the quality of the interface
between the residual limb and the
prosthesis.” Marks & Michael (2001)

FORCE ACTS ON A SOCKET

There are three types of forces act on socket during normal gait.

·          Impact forces generated when heel strikes the ground.

§  Soft liner and shock-absorbent feet minimize impact forces.

·         Rotation forces occur during the stance phase can cause rotation in the socket. The shape of the socket combined with special connective techniques (e.g. negative pressure) can be used to minimize rotation forces.

·         Shear forces also known as lifting forces. Occur during the swing-through phase, and can be controlled with the help of the right liner material and correct closure system. 

    MATERIALS USED IN A SOCKET

•       P.V.A files

•       Stockinet

o   Perlone

o   Nylone

o   Dacron

o   Cotton

•       Fiber glass/carbon fiber

•       Risins

•       Hardner

•       Accelerator(catalyst)

•       Socket adapter

TYPES OF SOCKET

•       Leather sockets(Provide flexibility and Adjustment),

•       Wooden Sockets.

•       laminated/moulded

o   They are total contact sockets.

•       Flexible

•       Rigid

•       Mainly there are four types of sockets

1.       Patellar Tendon Bearing (PTB).

2.       Kondylen buttlen munster (KBM)

3.       Supra condylar (medial wedge).

4.    Supra-condylar and supra-patellar. 

TYPES OF PROSTHESES

TYPES OF PROSTHESES 

·         There are five generic types of prostheses: postoperative, initial, preparatory, definitive, and special-purpose prostheses.

·         Although progression through all five levels may be desirable, only selected amputees will receive the postoperative or initial prostheses, which are directly molded on the residual limb.

·         Most amputees will have preparatory and definitive prostheses, but a much smaller number will receive special-purpose prostheses for showering or for swimming and other sports.

1.       Postoperative prosthesis.

2.       Initial prosthesis.

3.       Preparatory prosthesis.

4.       Definitive prosthesis.

5.       Special use prosthesis.

Initial Postoperative Prostheses (IPOP)

 There are more aggressive approaches to post operative care that may include the use of a rigid

Dressing or what is termed an Immediate Post-Operative Prosthesis or IPOP. An IPOP is an

Immediate postoperative prosthesis that is used as an early form of prosthetic intervention.

•       The benefit of being fit with IPOP prosthesis is early ambulation if allowed by your physician. IPOP prosthesis is also said to help with phantom limb sensation, because you can see that there is a leg, or in this sense, prosthesis attached.

•       IPOP prostheses also protect the residual limb from being injured.

•       Many times, a patient will wake up in the middle of the night to use the restroom, and

Forget that their limb has been amputated.

•       When they get out of bed and try to stand on both limbs, they fall down and re-injure

The surgery site.

•       An IPOP prosthesis will protect the end of the residual limb should this occur.

•       There are many different types of postoperative care and your physician will help you choose which the best is for you.

•       Postoperative prostheses are, by definition, provided within 24 hours of amputation.

•       These are often referred to by various acronyms including immediate postsurgical fitting (IPSF) and immediate postoperative prosthesis (IPOP).

•       Although technically feasible for virtually any amputation, postoperative fittings are currently most commonly prescribed for the younger, healthier individual undergoing amputation due to tumor, trauma, or infection.

•       Its use in the elderly or dys-vascular individual is controversial but can be successful when meticulous technique and close supervision are available.

Initial Prosthesis

•       The initial prosthesis is sometimes used for the postsurgical fitting and is provided as soon as the sutures are removed.

•       This is sometimes referred to as an early postsurgical fitting (EPSF). Due to the usual rapid atrophy of the residual limb, the EPSF is generally directly molded on the residual limb by using plaster of paris or fiberglass bandages.

•       An alternative is to use a weight-bearing rigid dressing. Such devices are used during the acute phase of healing, generally from 1 to 4 weeks after amputation, until the suture line is stable and the skin can tolerate the stresses of more intimate fitting.

•       Postoperative and initial prostheses are most commonly used in rehabilitation units or in hospitals with very active amputee programs. 

Preparatory Prosthesis

•       Preparatory prostheses are used during the first few months of the patient's rehabilitation to ease the transition into a definitive device.

•       They are also used in marginal cases to assess ambulatory or rehabilitation potential and help to clarify details of the prosthetic prescription.

•       The preparatory prosthesis accelerates rehabilitation by allowing ambulation before the residual limb has completely matured.

•       Preparatory prostheses may be applied within a few days following suture or staple removal, and limited gait training is started at that point.

•       Originally, the preparatory prosthesis was a very rudimentary design containing only primitive components.

•       The modern preparatory limb, however, usually incorporates definitive-quality endoskeletal componentry but lacks the protective and cosmetic outer finishing to reduce the cost.

•       It allows the therapist and Prosthetist to work together to optimize alignment as the amputee's gait pattern matures.

•       Different types of knee mechanisms or other components can be tested to see whether individual patient function is improved.

•       Preparatory prostheses are generally used for a period of 3 to 6 months following the date of amputation, but that time can vary depending on the speed of maturation of the residual limb and on other factors such as weight gain, weight loss, or health problems.

•       The new amputee may begin by wearing one thin prosthetic sock in the preparatory prosthesis; after 3 months, he may be wearing ten plies of prosthetic socks to compensate for atrophy.

•       When the number of plies of prosthetic socks the patient must wear remains stable over several weeks, it is usually an indication that the definitive prosthesis can be prescribed.

 Definitive Prosthesis 

•       The definitive prosthesis is not prescribed until the patient’s residual limb has stabilized to ensure that the fit of the new prosthesis will last as long as possible.

•       The definitive prescription is based primarily upon the experience the patient had when using the preparatory prosthesis.

•       The information learned during those months will demonstrate to the clinic team the patient's need for a lightweight design, special types of feet or suspension, or any special weight-bearing problems that may arise.

•       Unless a suction socket is used, the amputee wears prosthetic socks over the residual limb for the same reason that people wear socks when wearing shoes: the textile fibers provide cushioning and comfort, take up shear forces, and absorb perspiration.

•       An additional advantage is the ability to accommodate minor volume fluctuations by wearing more or fewer layers (plies) of prosthetic socks.

•       Once the amputee is wearing ten plies of prosthetic socks, the fit has degraded sufficiently that socket replacement should be considered.

•       A definitive prosthesis is not a permanent prosthesis since any mechanical device will wear out, particularly one that is used during every waking hour.

•       The average life span for a definitive prosthesis is from 3 to 5 years.

•       Most are replaced due to changes in the amputee's residual limb from atrophy, weight gain, or weight loss.

•       Substantial changes in the amputee's life-style or activities may also dictate a change in the prosthetic prescription.

•       Overall physical condition is also a factor since the more debilitated individual generally requires a very lightweight and stable prosthesis.

Special-Use Prostheses

·         A certain number of patients will require special-use prostheses designed specifically for such activities as showering, swimming, or skiing.

·         It is most economical if special-use devices are prescribed at the same time as a definitive replacement is necessary since both can be fabricated from the same positive model.

·         Most require specialized alignment. For example, swimming prostheses are made waterproof and aligned so that the patient can walk without a shoe.

·         In some cases the foot can be plantar-flexed and have a swim fin attached.

·         Snow skiing prostheses require an increase in dorsi-flexion at the ankle and may incorporate additional knee support or auxiliary suspension.

·         Special-use prostheses can be valuable to the amputee who wishes to expand his activities and participate in a full range of sports and recreational activities. 

STUMP PREPARATION PROTOCOLS

Prosthetics & Orthotics in Pakistan.

As Pakistan is among the Developing Nations, and Prosthetics & Orthotics Sciences is not priority for govenment and business sectors. Nationally it was introduced after the earthquake 2005 when there were hundreds and thousands of patients were reported with amputations and looking for some supportive devices for their mobility and social integrity. The provision of artifical limbs and supporting devices was the responsibility of sitting govenment but unfortunately the need was fulfilled by the NGO's and no initiative was taken at government level to establish the state of the art Prosthetics & Orthotics Department even in a teaching hospitals.

The second main factor of the delay in introduction of field at national level was the attitude of the very 1st Institution of Orthotics & Prosthetics Sciences in Pakistan. O&P was limited to a specific region and to the specific community and rest of the Nation was even unaware about the presence of that institution. Ater the earthquake a change was noted and foreign trained Rehabilitation and Orthopedic Surgeons worked for the establishment of O&P centres in teachning hospitals for the provision of services.

Currently 4 institutions are working for the education and training of Prosthetics & Orthotics in Pakistan.

Rawalpindi Medical College & Kind Edward Medical University are working in Punjab where as Pakistan Institute of Prosthetics & Orthotics Sciences in Peshawar and Dow University of Health Sciences in Karachi. 

No efforts are seen at government level to support the physically disabled population to start a new life with new aims, by using artificial limbs or supporting devices as they are unable to provide the food to all. Its very challenging for upcoming P&O to survive in this hard situation but there are lots of opportunities yet available to serve the nation other then government sector.

1st National Orthotics & Prosthetics Conference was organized by the Pioneer batch graduates of Rawalpindi Medical College and Founder Executive body of Prosthetics Orthotics Society of Pakistan. It was appriciated and a gross change was noticed in seniors attitude towards the promotion of profession. Many of them yet using the junior professional for personal businesses and benifits.

As we as I belive no one is perfect in her/his field but needs continous strugle and hardwork. I belive that we should promote the research work and go for establishment of our own resource centres. We need to be unite and productive for the national and humanitarian intrests. No nation can grow in the absence of their own standards and litratures. So beyond the racial and personal interests we should need to work for the profession and for the professionals. This will ultimately give us respect and honour.

Carrier in OnP

Job Description of Prosthetist & Orthotist (P&O) 

P&O is one among the key players of Rehabilitation team. In simple words Rehabilitation team is nothing in the absence of a P&O. They can work either work as

1. Rehabilitation Team Member.
2. Practitioner.
3. Industrial Manufacturer.
4. Material/Components Distributor.
5. Researcher.
6. Trainer.

Government Level Jobs in Pakistan

Currently there is no job structure of Orthotics & Prosthetics Professionals in Government Sector. As the services are very costly and Governments are providing free of cost medical services, its difficult for them to start standard rehabilitation centres at district level. That is why there are a few government jobs are available. Most of the professionals are working with NGO's or at their own by establishing their own Orthotics & Prosthetics Clinics.

No Master degree course is available till now is Pakistan. Many of professionals are looking fedup and frustrated. As well as student futrue is concerned they should focus on their curricular activities and practical work. This is the only key which can lead to excellen in Professional life. Students must having good practical knowledge and skills needs nothing to be worried in future as they can work any where in Country and even in World. Masters degree is easy and you can accomplish your task without any hurdle and hardwork if one have good practical experience and knowledge.

In current Science race and professional needs to work more hard then past for recognition. In recent decades Clinical Research has become a very important aspect for success. One who is working in any speciality sould be a good research so that he or she could be able to contribute new things and to share his practical experience with professional communities and researchers.

Introduction to Orthotics & Prosthetics Sciences

      Orthotics and Prosthetics Sciences is branch of Physical Medicine and Rehabilitation (PM&R). It is the combination of two different speciality known as "Orthotics" and "Prosthetics". The Detailed Introduction is given below.

Orthotics Sciences

                            It is the branch of PM&R deals with the prescription, designing, fabrication and fitting of the appropriate orthopaedic appliance to the physically disabled person or with other muskuloskeletal disorders.

                            Orthotist is a Professional, asses the patient, prescribe the appropriate appliance, Fabricate and design and then fit to the patient.

Prosthetics Sciences

                            It is the branch of PM&R deals with the prescription, designing, fabrication and fitting of the appropriate orthopaedic appliance (artificial limb) to the person with amputation.

                            Prosthetist is a Professional, who asses the patient, prescribe the appropriate appliance, Fabricate and design and then fit to the patient.

History of Orthotics & Prosthetics in Pakistan.

Prosthetics & Orthotics Sciences in Pakistan was started by German Organization GTZ during/after Afghan & Russian War. 1st Institution was established named "PETCOT" in Peshawar later on renamed and now working as "PIPOS". May graduates are serving nationally and internationally. The field was remained silent and there was no public awareness about this speciality. After the earth quack 2005, the field came under the consideration as it was highly needed for the physical rehabilitation of amputees because there was a high rate of amputees due to earth quack. After this NGO's started their work and delivered the state of the art Orthotics & Prosthetics appliances.

After that 3 Institutions University of Health Sciences at Rawalpindi Medical College, King Edward Medical University Lahore and DOW University of Health Sciences started 4 years graduation in Orthotics & Prosthetics Sciences. In 2012 their 2 batches has passed out and now working Nationally and Internationally.

There are so many academic programs, that were organized by the institutions but great turn was came in history when Prosthetics Orthotics Society of Pakistan and Rawalpindi Medical College, Rawalpindi Organized 1st National Orthotics and Prosthetics Conference Successfully on 15,16 December 2012. After this conference so many changes were noted in Orthotics & Prosthetics profession in Pakistan and people start sharing their knowledge and expertise with each other as conference allowed them to get connected to each other.