Prosthesis of the shoulder
The metal components can be fixed to the bone thanks to a special resin (acrylic cement) or a simple embedding that will allow a later "biological" fixing (non-cemented prosthesis).
The choice among the different kinds of prosthesis is based on different factors (quality of the bone tissue, type of pathology, degree of joint deformity, age of the patient).
The aim of the operation is to make the joints not hurt anymore, to put them in a good axis, to ensure sufficient mobility range that allows walking and most common everyday movements.
We must not forget, though, that, contrary to human body tissue, prosthesis do not have any biological maintenance power and therefore, once they are implanted, they are eventually going to wear. The better the joint is used, the slower the wearing process will be in time. It is therefore vital to take good care of the operated joint, follow simple behavioural rules and take simple precautions: it is important to avoid traumatisms and useless stress.
In the few months right after the operation, other movements (extrarotation of the limb) that might induce the luxation of the prosthesis, that is the disassembly and the consequent loss of connection between the two components of the joint, need to be carefully avoided.
Right before the operation (when it is possible), a blood pre-deposit is usually required (a certain amount of blood is taken from the patient) so that it is available during the operation (self-blood transfusion) should the need arise to compensate losses due to the operation.
The kind of anaesthesia used can be either general or peripheral (interscalenic brachial plexus). The choice will be made by the anaesthetist in line with the patient's general conditions.
In the first few hours before and after the operation, the patient will have to follow an anticoagulant therapy (in order to decrease the risk of phlebo-thrombosis), an antibiotic therapy (to decrease risk of infections), and an analgesic therapy (only if necessary).
The following POST-OPERATIVE COURSE can be described as follows:
Passive movement of the limb starts the first day after the operation (as soon as the drainage tubes are removed);
The passive kinesitherapy phase continues for three weeksand the physiotherapist helps the movement of the shoulder in all the movement directions, being very careful not to stress extrarotation too much. While pausing, the limb is kept in a soft anti-rotatory bandage; active pendular movement is allowed.
Usually, the patient leaves the hospital 4-5 days after the operation.
After 20 days, the active kinesitherapy begins; the bandages are removed and the assisted active movements begin.
Physiotherapy usually continues for about 2 months after the operation; passive movement of the whole joint area continue and re-habilitation in special pools (hydrokinesitherapy) can actually begin.
Active movements can be carried out freely; later on, new exercises, with higher resistance and increasing difficulty, will be introduced. Rubber bands may be used to increase resistance in the exercises.
Out-patients check-up examinations are performed:
A few days after leaving the hospital to remove surgical stitches (in case this did not happen during hospitalisation);
45 days after the operation with X-rays of the shoulder in front-back and axial projection (axillary);
every following year, with new X-rays (see above).
POSSIBLE COMPLICATIONS LINKED TO THE ARTHROPROSTHETIC SURGERY OF THE SHOULDER
In the past few years, the prosthetic surgery of the shoulder has definitely seen an improvement of the prognosis aspects, thanks to advanced techniques and to the continuous improvement of the material used.
However, in order to provide correct and adequate information to the patients, it is also necessary to remind that the primary aim of this kind of surgery is the complete disappearence (or drastic reduction)of painful symptoms, while the rehabilitation of the joint's active functionality cannot be precisely predicted as it depends on a variety of different factors such as:
type of basic pathology: functional rehabilitation is definitely greater in the case of prosthetic surgery for primary arthrosis. In the other cases, functional impediments depending on the muscular efficiency should always be envisaged. In particular surgery, in the case of traumatic pathologies and, more frequently, in case of rotator cuff deficiencies, only allows a partial rehabilitation of movements which cannot be predicted before the operation.
Quantity and quality of the rehabilitation program.
Patient's collaboration.
Intra-operative complications:
Fractures occurring during surgical manoeuvres: usually a consequence of the poor mechanical characteristics of the bone tissue. They might require a change in the technique used.
Vascular lesions (possible, and sometimes large, blood losses).
Nerve lesions to the axillary nerve or other branches of the brachial plexus.
Post-operative complications:
Luxation of the prosthesis: it indicates the loss of connection between the two components of the new joint; it is often induced by wrong postures and movements; moreover, it can also be the result of muscular insufficiency of the shoulder girdle. Statistically, however, this is a rather rare complication if compared to the arthroprosthetic surgery of the hip.
Thrombosis of the deep veins of the leg: definitely, this complication arises far less frequently if compared to any prosthetic surgery performed on the lower limbs (prosthesis of the hip and of the knee); its signs are a large swelling of the foot and the leg itself, a strong sense of heaviness of the limb and calf pain. In order to decrease the occurrence of such complication, it is necessary to carefully follow the heparin therapy recommended when leaving the hospital, start the rehabilitation therapy as soon as possible and follow it consistently.
Pulmonar embolism: it indicates the detachment of a thrombus that has developed in one of the veins as a consequence of the previously described complication. The thrombus reaches the lungs and causes chest pain, difficulties in breathing, cough, sometimes bronchial catarrh containing a little bit of blood. This is a very dangerous complication that requires immediate hospitalisation in an internal medicine ward. In order to prevent such complication from arising, the same preventive measures for deep vein thrombosis need to be followed.
Infection: the signs of its acute form are a very high fever, strong pain in the operated knee, which feels particularly swollen and hot. The signs of its subacute form, instead, are a light but constant fever, strong pain in the operated knee which appears swollen and very hot. This complication is very important but sometimes it can be overcome with a new heavy-dose antibiotic therapy to be followed for a few weeks, often during hospitalisation. If this treatment does not lead to any improvement, then the removal of the prosthesis may be envisaged.
Aseptic detachment of the prosthesis: this is usually a late complication; this term indicates a progressive detachment of the components of the prosthesis from the bone, which is not a consequence of infection. If it is very extended, it may require a re-implant of a new prosthesis.
Peri-prosthetic ossifications: they develop (for unknown reasons) during the first few months after the operation and lead to a partial loss of the range of motion of the joint.