Endoprosthetics of hand joints (hand and wrist)

When a joint is destroyed - complete or partial - a person suffers unbearable pain. The organ loses its functional features, which can lead to disability. For some time, the patient can use painkillers and physiotherapeutic procedures, but only prosthetics can radically change the situation.

Medicine is trying to restore joint function using conservative methods, but serious changes are not amenable to such treatment. If there is damage to bone tissue or completely worn out cartilage, no medicine will correct the situation.

Endoprosthetics of hand joints is most often in demand among elderly people. It allows you to move actively and feel good. Thanks to such operations, the patient returns to his normal life without pain.

Prosthetics, like any operation, has risks. They are defined:

• health status;
• the severity of the problem;
• type of prosthetics.

Before the operation, a thorough examination is carried out to identify indications and contraindications for this action.

Indications for prosthetics

• joint deformation after injury;
• long-standing dislocation;
• chronic joint inflammation;
• pain that cannot be relieved.

What is prosthetics?

This is the restoration of lost limbs using artificial products. Depending on which part of the body was amputated, the patient is fitted with appropriate prostheses.

Modern prosthetics help people restore their physical tone and rehabilitate themselves in society.

Millions of people after amputation continue to live an active and fulfilling life, rejoice and enjoy every day. They travel, start families, work. Today the word amputation does not sound like a sentence.

Reasons for limb amputation

An absolute indication for amputation of limbs can be accepted by a doctor in the following cases:

* injuries;

* gangrene (infection, frostbite);

* oncology;

* rupture of blood vessels, soft tissues.

Relative indications, taking into account the patient’s health condition, include complex trauma when reconstruction of the limb is not possible, also as a result of paralysis or trophic ulcer.

How does the amputation process occur?

Amputation consists of several stages:

First stage. A meeting of doctors at which amputation options are discussed and approval for the patient's operation is obtained.

Second step. Includes the actual surgery to remove the limb. The patient is put under anesthesia and taken to the operating room. The doctor makes an incision in the soft tissue, and the vessels are ligated. The bone is cut down. There are certain ways to cut down bone to eliminate the risk of difficulties.

Last stage. Formation of a stump and covering it with skin flaps. The scar is not made at the base of the support so that there is no load on it.

Limb amputation occurs in such a way that the patient does not experience complications or phantom-type pain in the future, and there is also the possibility of trouble-free installation of prostheses.

Rehabilitation is not included in the program of the operation, but this part is important for the patient.

What types of prostheses are there?

The latest prosthetics technologies make it possible to create both entire limbs and parts. For example, prosthetic legs, prosthetic fingers.

Elbow joint, hip and shoulder, foot - this is not a complete list of prostheses presented on the Russian market.

Prostheses can be divided into 2 types:

· Cosmetic. Designed to hide some shortcomings in physiology.

· Functional. Allows the restoration of physical capabilities as a result of a lost limb.

Functional ones can be divided into:

· Workers;

· Mechanical;

· Bionic.

A working prosthesis is made in such a way that people can use it to perform work or play sports. The working prosthesis has different attachments that perform specific functions (for example, an attachment with a fork, screwdriver, etc.)

A mechanical prosthesis is made without electricity. It consists only of a cable and a spring. This is an inexpensive prosthesis, its price is significantly lower if you look at bionic models.

A bionic prosthesis is a prosthesis that has touch-type sensors, a microprocessor, an electric motor and a rechargeable battery, as well as many more complex components. It is considered the most expensive among those presented above.

What are dentures made of?

The prosthesis consists of a prosthetic sleeve, frame, and cosmetic shell.

A cosmetic prosthesis is made of silicone; if desired, freckles or moles can be applied to the coating; there are even types of cosmetics where you can paint your nails. And it all looks very realistic.

A bionic prosthesis is made of high-strength materials; sometimes a shell is made onto the bionics. However, this is how the bionic prosthesis is most often worn.

Prosthetic legs and arms are made in prosthetic workshops; in every region of Russia there are such enterprises, for example, a branch of the Federal State Unitary Enterprise “Moscow Prosthetic Enterprise” or private ones, such as the prosthetic and orthopedic center “Salut Orto”.

There are also companies on the market that produce semi-finished products, individual feet or knee modules. The most popular will be Ossur (iceland), Ottobock (Germany), Steplife (Russia), Vincent Systems (Germany), Taska (new Zealand), Steeper (Great Britain), Metiz (Russia).

Let's look at how a bionics-based prosthesis works.

The bionic prosthetic arm works by reading the energy potential from the muscles of the stump. The sensor picks up the signal, sends it to the processor, which then converts these signals into a driving process.

When a person tenses his muscles, the product begins a gripping action; when he relaxes, the prosthesis also returns to its original position.

A bionic prosthetic leg is more complex because it is a support point. The basic principle of its operation is that it contains various sensors for speed, angle of inclination, acceleration, information from which is fed to the processor installed on this prosthesis. A bionic prosthesis allows a person to walk more naturally.

Preparation for prosthetics

When an amputation has occurred, after 30 days you can begin installing a temporary prosthesis, or it is also called a therapeutic-training prosthesis. It is needed in order for the limb to adapt to the product for constant wear.

It can take 3 to 6 months for the stump to get used to the prosthesis. During this time, the patient focuses on his feelings: whether he is comfortable or not. At this stage, the prosthesis is adjusted to the person’s size and adjusted to his wishes.

At the moment, the prosthesis looks unpresentable; it is intended only for temporary wear.

At the same time, a training hip prosthesis helps the patient learn to walk, get used to the design, and the main task of such a prosthesis will be the correct formation of the stump of the lower limb.

A hip prosthesis is a complex design to manufacture. It is made from an individual plaster cast based on a detailed medical analysis, and takes into account all the patient’s health characteristics.

A specialist from the prosthetic center will tell you how to get a permanent hip prosthesis, and he will also advise on possible options for making prostheses.

Prosthetics of the upper and lower extremities

Lower limb prosthetics involves many factors. The specialist pays attention to many factors: age, weight of the patient, physiological characteristics.

It is necessary to take into account what part of the leg was amputated; if it is the hip, then there is a modular and non-modular hip prosthesis, frame or splint-leather.

The most important thing in a modular prosthesis is the knee module. Locking (mechanical) knee modules of hip prostheses are used as a primary prosthesis for an inactive group of patients.

For an active group of people, modules with pneumatic control and hydraulic control are used.

Modular helps restore the patient’s full functionality and mobility, while such a prosthesis is completely safe to wear.

A non-modular prosthesis is most often installed in older people who are not highly active.

A modular prosthesis is many times superior to splint-leather and frame prostheses.

Advantages of a modular prosthesis:

✔unlimited movement;

✔ ability to regulate speed;

✔easy to replace components;

✔ look close to natural.

It is worth considering that with the help of simple prostheses you can take leisurely walks, but for people leading an active lifestyle, more modern options are suitable.

Upper limb prosthetics include hand and finger prostheses.

Amputation of these parts is often associated with accidents and injuries or damaging accidents that prevent limb salvage.

In the modern prosthetics market, there are many options for prostheses that will take into account the nuances of using products. For example, to drive a car, you can use either a special attachment for a working prosthesis or a prosthesis equipped with electronic control.

Prosthetic fingers are now only cosmetic in nature until a prosthesis has been created that can recreate the functionality of the individual finger.

As for hand prosthetics, the choice is wide, from cosmetic to functional.

Don’t forget that it is possible to get a prosthesis for free, you just need to know the rules for free lower limb prosthetics in Russia.

Contraindications

• amyotrophy;
• disturbance of blood supply;
• destruction, inability to retain the endoprosthesis;
• concomitant diseases in the acute stage;
• high physical activity with the impossibility of limiting the high load on the joint requiring replacement;
• If the patient refuses to follow instructions.

Endoprosthetics of the finger joint to restore their mobility is used for rheumatoid polyarthritis. As a means of recovery from injuries, the use of the technique is limited, and even vice versa - damage to tendons and ligaments due to injuries is considered a contraindication to prosthetics.

The problem is solved in stages:

• restore the correct anatomical structure;
• prepare the soft joint;
• a prosthesis is installed.

The risk of side effects increases if:

• a person is actively involved in sports;
• gives physical stress to the joint;
• with a tendency to fall;
• for infectious and allergic diseases.

After the operation, doctors monitor the recovery process to ensure a favorable outcome.

Rules and procedure for obtaining prostheses

After amputation, rehabilitation is necessary, since the prosthesis is not installed immediately. First, the limb needs to heal completely, and only then a prosthesis is selected.

How to get a prosthesis for free?

Each region has a prosthetic center, which can be found through the help desk or the Internet. You can also contact the regional office of the Social Insurance Fund and they will tell you which prosthetic center will be most convenient and closest in distance. According to Russian Federal Law No. 181, people in need can receive a prosthetic limb free of charge. He can also pay with his own funds and then receive compensation from the state. Reimbursement varies from region to region, so please contact your local prosthetic center for advice.

Second generation of prostheses

The second generation of implants was associated with a change in the locking mechanism. The rigid rectangular shape, which excludes abduction/adduction, has been transformed into the “ball & socket” shape. Thus, the possibility of two degrees of freedom was realized in the prostheses. The friction pair more often began to be metal and polyethylene. Using the Griffit-Nikoll prosthesis as an example, a proximal phalanx roller component made of steel was presented, juxtaposed with a metacarpal cup component made of polypropylene. The hemispherical matching portion was coated with silicone to minimize soft tissue damage.

A three-year series of studies [11] showed a very low fracture rate of such implants. The additional degree of freedom appears to have contributed to the redistribution of stress across the nodal joint. The central problem was the return of ulnar deviation, as well as several cases of infection. On the other hand, the return of ulnar deviation can be explained by insufficient preparation of the soft tissue component surrounding the joint. In other words, the question arose about individual plastic reconstruction of the tendon-ligamentous apparatus or expanding the possibilities of the geometry of the articulating surfaces.

This was followed by a huge number of developments of implant models from different types of materials. All studies were conducted on small groups of patients and presented a high rate of complications. As a result, most of them - Garcia-Moral, Strickland, Walker I, Walker II, etc. - were banned from use [12]. The positive side of these works were the conclusions about the need to study many issues. The researchers worked on the length, number, cross-sectional shape and roughness of the prosthetic legs. The latter, together with notches and transverse notches, may have been aimed at increasing the stability of the fixation of components in the bone canal. In connection with the use of the new material, complications appeared due to the formation of polyethylene decomposition products, and difficulties in revision surgical interventions with the cement method of fixation were also noted [12].

An example of work of that time assessing early and mid-term results is the research of R. Beckenbaugh and A. Steffee [13]. The authors consistently presented three models of the Mark prosthesis (Fig. 3).

Rice. 3. Implants Mark I (a), Mark II (b) [15]. The models were a metal-polyethylene friction pair fixed with cement. Each model was studied for 10 years, starting in 1964. The results of the latest model were published in 1997. Complications occurred in 50% of cases, after which the last modification (the Mark III prosthesis) was also prohibited from use. The decomposition products of the metal-polyethylene friction pair also caused the development of inflammatory and resorptive processes. Cementing, in turn, became a “stumbling block” during revision operations, since removing cement was a technical difficulty.

In terms of identifying new complications, an important milestone was the work of B. Adams et al. [16] using Shultz models (Fig. 4, a).

Rice. 4. Appearance of implants Schultz (a), Steffee (b), St. Georg-Buchholtz (c) [14]. The two-component prosthesis was represented by a friction pair of high-performance polyethylene and cobalt-chrome. It was installed using cementation. HDPE polyethylene is characterized by hardness, rigidity, tensile and compressive strength, chemical resistance, flexibility and elasticity in the temperature range from –70 to 100 °C. As for the cobalt-chrome alloy, the mechanical strength properties of cobalt are supported by the anti-corrosion properties of chromium. An alloy processed by the “polishing” method is characterized by exceptionally low roughness and a correspondingly low level of formation of decomposition and friction products. The main problem of the prosthesis was frequent cases of fractures of components near the junction, heterotopic ossification in 100% of cases and loosening of components, confirmed by x-ray changes in the surrounding bone tissue in the form of stripes of increased intensity. In addition, after installation of prostheses, ulnar deviation occurred. The results give reason to think about the direction of tension forces, “shearing” forces, and maximum permissible loads in relation to each of the designs.

Around the same time, a series of studies of aluminum-ceramic KY prostheses were presented, based on the MINAMI model [17, 18]. Both models had a metacarpal stem made of polycrystalline aluminum and a proximal phalangeal stem made of monocrystalline aluminum coated with high-density polyethylene. All prostheses were installed without the use of cement. The prosthesis also had two degrees of freedom. The results revealed an extremely low mean range of motion in the postoperative period. The weaknesses of the prosthesis of this design were the quality of the ceramics, uncontrolled porosity of the material during manufacturing, the uniformity of the ceramic “grains” and the presence of additional inclusions. This probably explains the large number of fractures (Mahoney and Dimon series). Thus, the focus shifted to the use of other materials.

Obtaining a prosthesis at the expense of the state (for the first time).

To receive a prosthesis for free, you need to contact the manufacturer of the prostheses so that he can select the prosthesis and appoint a commission to issue a medical and technical report.

The second step will be to contact the hospital or medical center where you are registered at your place of residence. You receive a referral for a medical examination.

After passing the medical examination, you must receive a disability group.

After this, a referral is issued from the Social Insurance Fund with the opportunity to contact the manufacturer of prosthetic structures to obtain a prosthesis.

If you are going to buy a prosthesis at your own expense, then everything is simple. You receive a conclusion, order the product, pay and receive it. Next, you are paid compensation for the funds spent.

First generation of prostheses

Certain types of prostheses for metacarpophalangeal joints were created back in the 1950s. Experts have developed models of connected prostheses with a metal-metal friction pair. In 1959, E. Brannon and G. Klein [4] presented 2 cases of using titanium models for prosthetics of metacarpophalangeal joints. The prosthesis consisted of two components connected by a half-thread screw. The surface was beveled to reduce friction and irritation to surrounding soft tissue. Each section contained a centered leg with a triangular sectional plane to eliminate the rotational component after installation. The rigid rectangular contour of the nodal joint provided one degree of freedom in the joint.

The clinical study was limited to 2 cases of use with a follow-up of 2 years. The authors noted a significant decrease in the average range of motion of the joints and shortening of the fingers. One of the prostheses caused bone resorption with subsidence into the bone after surgery. Subsequently, they also provided information about the “magnetization” of surrounding tissues by metal components. In order to reduce the degree of subsidence, the modification of the prosthesis consisted of introducing special staples both through the legs of the prosthesis and through the hub connection (Fig. 1).

Rice. 1. Endoprosthesis proposed by E. Brannon and G. Klein (1959) [5]. Perhaps, in order to reduce magnetization, stainless steel was added to titanium [4]. Don't forget about "metallose". As a result of friction, wear products of components are formed. They induce a reaction with the formation of prostaglandins E2, which in turn activate osteoclasts, the result of which are local resorption processes that reduce the stability of components in bone canals [6]. Although the results of using a modification of this prosthesis are not reported in the literature, it is believed that this served as the basis for further study of the possibilities of finger prosthetics.

A. Flatt [7], taking the Brannon & Klein model [4] as a basis, modified the design of the prosthesis in 1960 and presented his own model. The material used was stainless steel, produced by vacuum from a low-carbon alloy. This material was characterized by the absence of the “magnetization” effect and high anti-corrosion properties. The prosthesis had dual intramedullary legs, which were supposed to increase the osseointegration capabilities of the prosthesis, reduce the rotational component and the effect of subsidence into the bone that occurred when implanting Brannon & Klein prostheses. However, it can be assumed that duplication of the legs contributed to the formation of a system of “tension” between them, an increase in the severity of local resorptive processes and, ultimately, instability of the components. This was confirmed by the results of x-ray examination: in the vast majority of cases, bone resorption was observed, defined as a gap between the bone and the prosthesis. This caused subsidence and then migration of the structure into the proximal phalanx or metacarpal bone [9]. The surgeon had four standard sizes in his arsenal (Fig. 2).

Rice. 2. X-ray of the hand 5.5 months after installation of the prosthesis Flatt (1961).

A. Flatt and M. Ellison [8] modified the prosthesis a few years later by placing the flexion and extension axis more volar with respect to the legs of the prosthesis in order to ensure better functioning. The Flatt & Ellison series described a significant decrease in mean range of motion in the postoperative period. It was also reported that the physiological functioning of the arcs of motion in the replaced joints was preserved and the range of motion in the associated interphalangeal joints was increased due to their reciprocal irritation.

Complications of using the same prosthesis are described in a series of observations [10]. Prostheses were installed not only in the metacarpophalangeal, but also in the interphalangeal joints. No division of complications by localization was presented. However, information was provided on four main types of complications: extensor dislocations, axial rotation of the fingers, return of ulnar deviation, and subsidence of implants. If the first three complications occurred in 50% of cases, then the frequency of the last complication reached 80%. These prostheses may be considered to have excessive hinge stiffness, allowing only one degree of freedom, as in the Brannon & Klein models. The excessive length of the legs of the proximal and distal components also attracts attention. Perhaps the author wanted to increase the stability of the implant due to the long lever of movement and a larger area of ​​contact “bone-material”. On the other hand, the long acting “arm” of the prosthesis leads to additional stress and the appearance of structural fractures in the future.

How to choose the right dentures

A properly selected prosthesis can improve the quality of life, restore a beautiful smile and a healthy appearance.

In case of complete absence of teeth, removable dentures on implants restore chewing function well and provide uniform load. This design is securely fixed. A cheaper option is plate dentures with suction cups.

In case of complete edentia, nylon dentures are not recommended; they have low suction ability and are difficult to chew solid food in.

In case of partial absence of teeth, clasp dentures have proven themselves well. They are firmly attached and distribute the load evenly.

The choice of prosthesis for the upper and lower jaws has its own characteristics. You can choose any suitable option for the upper jaw; it lends itself well to prosthetics due to the large palate. It is better to install a prosthesis on implants or a clasp prosthesis on the lower jaw, since the sublingual space is small and the fixation is worse.

Removable dentures are a good budget option for dental restoration. They are easy to care for. They effectively cope with their function and look aesthetically pleasing. In practice, acrylic, clasp dentures, Acry-free, QuattroTi have proven themselves well.

How much do the best dentures cost?

Which material is better and will last longer?

The degree of reliability of fixation, comfort and aesthetics during use depends on the material from which removable dentures are made.

The main requirements for them include:

• strength;
• biocompatibility with human tissues;
• lack of toxicity, allergenicity, effects on taste and olfactory receptors.

Acrylic is the most popular and affordable material. It does not change its properties over time; acrylic dentures have good aesthetics. But it has a porous structure and can accumulate bacteria that cause inflammation.

Nylon is a lightweight and flexible material. Does not cause an allergic reaction and does not accumulate bacteria. Although it is durable, due to its softness and elasticity it quickly becomes unusable, so nylon dentures perform a good aesthetic function, but do not cope well with their intended purpose, chewing.

Acry Free is a modern material for removable dentures (translucent plastic that does not contain acrylic). It is elastic, does not injure the mucous membrane, and structures made from it are resistant to mechanical stress. This material is suitable for patients with allergies to metal or acrylic and with hypertonicity of the masticatory muscles. The service life of dentures made from it is longer than that of acrylic ones. The cost is higher than acrylic and lower than nylon and clasp.

Which denture is best for missing teeth?

Which orthopedic design is best used will depend on the individual characteristics of the patient and the number of remaining teeth.

For example, on the upper jaw, plastic dentures are fixed quite well. It will be impossible to fix it well on the lower jaw if mini-implants are not installed under the prosthesis.

If there is a complete absence of teeth in the upper jaw, it is better to choose a prosthesis made of acrylic, since due to the high elasticity of nylon there will be no suction effect.

Dentures made of plastic are more comfortable and effective when chewing than nylon ones, but nylon ones are thinner and lighter. They have better aesthetics in comparison with plastic and clasp ones, because the clasps of a nylon prosthesis are made of pink nylon, and the clasp ones are made of metal. However, clasps are easier to get used to and their service life is longer.