Shoulder joint is the most mobile joint in human body. It consists of a head of humerus and a glenoid cavity. As all other joints, shoulder joint is surrounded by a glenoid cavity that produces glenoid fluid. It reduces friction in joint, nourishes articular cartilage and stabilizes the joint.
Endoprostheses of shoulder joint allow restoring the angle and size of head of humerus and a glenoid cavity that are individual in every patient.
Besides, when needed, a worn cartilage in head of humerus can be replaced by an artificial joint. When the damaged cartilage of the head of humerus is replaced, a prosthesis of humerus head is used.
Today, the life cycle of an artificial shoulder joint is about 10-15 years. Besides, it also depends on the level of load, quality of bone tissue, and material and construction of endoprosthesis.
When the results of preliminary research are evaluated, your doctor will evaluate the most suitable type of endoprosthesis and the method of fixation in bone tissue. It depends on patient’s age, quality of bone tissue, severity of arthrosis and degree of damage of rotator cuff.
If arthrosis has mainly damaged the head of humerus, and the glenoid cavity has enough cartilaginous tunic, and there are no considerable deformations, it will be enough to replace only this part of joint with an endoprosthesis.
There are two main types of endoprostheses. In most cases, a prosthesis of a head of humerus is used – all allows restoring the relation of proportions and axes in head of humerus. The core of the prosthesis is tightly fixed in bone pipe of shoulder.
Alternatively, only surface of head of humerus can be worn. In this case, it is closed with a metal “cap”, s0-called superficial prosthesis. In such instance, fixation of endoprosthesis in bone pipe is not appropriate. When a lot of tissue in head of humerus is damaged, a superficial prosthesis is not enough, because it cannot be fixed reliably.
When the cartilaginous tunic is seriously damaged, and there’s pronounced deformation of head of humerus together with glenoid cavity, as a rule, both parts of joint should be replaced. In this cases, a total endoprosthesis of a shoulder joint is required.
Patients with total endoprosthesis of shoulder joint experience less painful sensations and have better mobility of joint compared to patients who have a humerus head prosthesis implanted. However, replacement of glenoid cavity is not possible in case of amphiarthrosis and in patients experiencing considerable load on shoulders and serious loss of bone fluid in the area of cavity.
When rotator cuff is damaged and patient experiences arthrosis, movement of arms can be restricted, so a patient may need a special endorposthesis. Such implant is not suitable for movement of joint within a rotator cuff, and is called an inverse (contrary) endoprosthesis. Head of prosthesis is fixed in the glenoid cavity in a way differing from the one used during fixation of a usual total endoprosthesis of shoulder joint.
Fixation of head of endoprothesis is made with the help of screws without cementation. To fix endoprosthesis of a shoulder joint, a doctor typically uses bone cement. A sliding polyethylene cover is put in the upper part of endoprosthesis to ensure sliding movement around the head.
The success of operation depends on patient, as well. Use the time before shoulder surgery to prepare for it and solve all organizational issues. Visit doctors after the operation, if you feel well: it will help you to get back to normal active life after the operation.
For how long do patients stay in the clinic?
Practice shows that patients usually stay in the hospital for 10-14 days. After that, rehabilitation measures are taken (that can be done in a hospital, or a special rehabilitation clinic).
Stages of surgery
The operation is made while patient is half-sitting. You will feel comfortable, as if you were sitting in a chaise longue.
To open the shoulder joint, a doctor makes a 15-20 cm long cut on the skin above the front part of shoulder. After that, a surgeon removes damaged elements of joint surface of head of humerus and glenoid cavity, worn elements of ligaments and synovial bursa, and inflamed mucous layer of the joint.
With the help of special instruments, damaged elements of cartilage and bone surface of head of humerus and glenoid cavity are prepared for implantation of the new shoulder joint.
Complications rarely occur after implantation of shoulder joint endoprosthesis. However, risks exist after any surgical invasion. These can be bleeding, secondary bleeding, or damage of adjacent nerves. Your doctor will consult you about risks.
Next day after operation, you can stand up and move in your ward and hospital. To reduce pain in the area of wound, you should spend first days after the operation with raised bed-head and take pain killers regularly.
To stop uncontrolled movements of joint, a patient should have his arm fixed with the help of a many-tailed bandage for several weeks. Movement of elbow and hand is allowed after operation. It helps to maintain blood circulation in the operated arm and prevents swelling. Experienced specialists of physical therapy will show the patient suitable exercises that should be performed several times a day.
Movement of the artificial shoulder joint is allowed in 2-3 days after the operation – the surgeon defines to which extent they can be moved. It’s necessary to follow doctor’s instructions to have ligaments and bones grow together correctly.
As a rule, restoration of function of operated shoulder joint relatively to horizontal surface is a pretty long-lasting process. Partial results are reached a year after the operation. Be patient and continue performing exercises for strengthening muscles and stretching joint capsule.