Indications: Osteoarthritis, Rheumatoid Arthritis, Trauma etc.
2-3 weeks prior to surgery.
Patients are seen in this specific clinic approximately 2-3 weeks prior to surgery. Here they under a thorough assessment by both medical and nursing staff. This includes simple blood and urine tests as well as the taking of swabs which identify patients carrying certain bacteria including MRSA. Mr Hartwright sees patients at this point in order to explain the nature of the surgery and possible risks, identify any possible problems, obtain the patient’s consent to surgery and, of course, to answer any outstanding questions the patient may have.
Spinal or general.
Patients normally receive either a spinal (a needle into the spinal area causing numbness below the waist), or general anaesthetic. On the whole, spinal anaesthesia is preferred as it causes fewer possible cardiorespiratory problems. There are potential risks with either technique and patients are encouraged to discuss any issues they may have with the Anaesthetist pre-operatively.
If a patient is thought to have any anaesthetic risk factors which may cause problems during, or after surgery, they are seen in pre-assessment clinic or given an appointment to see an Anaesthetist well before the day of surgery.
An anterolateral approach.
Mr Hartwright performs the operation through a vertical incision over the middle of the knee (midline incision). He uses what is called a medial parapatellar approach which divides the deep tissues around the inside of the knee next to the knee cap.
He uses cemented implants (i.e. requiring cement to hold them in situ) but varies the actual implants depending upon what he feels is best for the patient. The usual implants are made of Cobalt chrome, Titanium and Ultra High Molecular Weight Polyethylene (UHMWPE). Occasionally Mr Hartwright uses OxiniumTM (oxidized zirconium) which is thought to improve the longevity of the TKR.
Approximately 1 week.
The average hospital stay is approximately 5 days but this depends upon how quickly the patient recovers and rehabilitates.
POST OPERATIVE RECOVERY
Start moving as soon as possible.
Mr Hartwright encourages patients to start mobilising as soon as comfort allows. This is done under the supervision of either the physiotherapists or nursing staff. Most patients start to walk on the day following surgery. Prior to discharge, patients are taught how to walk safely with crutches and climb a small flight of stairs. They are normally expected to achieve knee flexion of at least 90° (a right angle) before they are discharged.
Patients are provided with instructions as to the exercises that they should perform once discharged. It is vital that they do these exercises in order to optimise the results of surgery.
Mr Hartwright uses clips to close the skin. These are removed at 10-14 days post-operatively. This is normally performed by the patient’s district or practice nurse.
Patients are discharged with compression stockings which are worn in order to prevent blood clots (Deep Vein Thromboses – DVT). They are instructed to wear these for 6 weeks.
Patients are allowed to drive at 6 weeks post-operatively so long as they feel safe to drive (and are able to perform emergency manoeuvres).
RISKS OF SURGERY
There are always risks associated with surgery.
In general complications are more common with Revision Hip Surgery compared with primary (first time) replacements.
Mortality PE Wound Inf Readmission Dislocation
Primary THA 1% 0.9% 0.2% 4.6% 3.1%
Revision THA 2.6% 0.8% 0.95% 10% 8.4%
Rates of complications occurring within ninety days after surgery (Rates and Outcomes of Primary and Revision Total Hip Replacement in the United States Medicare Population. JBJS (Am) 85:27-32 (2003))
It is impossible to perform joint replacement surgery without some loss of blood. If the level of Haemoglobin (the substance that carries oxygen to the tissues) drops below a certain level (anaemia), this can cause significant problems with the heart and other vital organs. Consequently, Mr Hartwright and his team monitor blood loss and the Haemoglobin (Hb) level very carefully.
Pre-operatively, the Hb is checked and where necessary treated to bring it up to an acceptable level before surgery is considered.
During the operation, techniques (including careful haemostasis) are used to limit blood loss and a drain is inserted into the operative site which salvages any blood lost.
Post-operatively, blood collected in the drain is given back to the patient and the Hb is checked again. If the Hb level falls below a certain level (which is patient/symptom dependent) a blood transfusion may be deemed necessary. There are risks involved with receiving blood transfusions (please refer to blood transfusion on www.blood.co.uk).
There is a risk of infection with any surgical procedure. Infection in joint replacement surgery is particularly problematic as it can lead, ultimately, to the failure of the joint replacement. Mr Hartwright takes great care to ensure that the risks are put at a minimum.
Pre-operatively: Patients are pre-assessed so as to identify patients who are at greater risk of infection and measures are taken to decrease these risks e.g. Identifying and treating those patients who are MRSA carriers or who have urinary tract or other infections.
Patients are advised to take care of their skin pre-operatively; any cuts or scratches may allow bacteria to enter a patient’s system and consequently increase the risk of infection.
During the anaesthetic, intravenous antibiotics are given in order to limit the potential effects of bacteria entering the surgical site.
All instruments are sterilised to strict guidelines.
Joint replacement surgery is performed in specially designed theatres (with air filters and laminar flow) so as to decrease the risk of airborne infection.
The surgical site is prepared using antibacterial solution with the aim of preventing the entry of bacteria from the patient’s own skin.
All theatre staff directly involved in the procedure thoroughly wash their hands and wear sterile gowns and gloves such that no unsterile object comes into contact with the patient.
Patients are given two further doses of intravenous antibiotics whilst on the ward after surgery.
The surgical site is covered with a dressing so as to avoid infection from direct contact.
The rate of infection in patients undergoing joint replacement surgery is generally quoted as 1%. Link to RHCH infection rates.
Mr Hartwright’s rate of infection for joint replacement surgery is under 0.3%
Post-operatively most patients are provided with Patient Controlled Analgesia (PCA). This is an intravenous delivery system which allows the patient to give themselves a fixed dose of a morphine based analgesia through the pressing of a button.
Patients are encouraged to inform either the nursing and medical staff if they are experiencing pain. There are many analgesic agents at our disposal and there is no longer any need for patients to suffer in discomfort.
Following lower limb joint replacement surgery there is a risk of patients developing clots either in the deep veins of the legs (DVT) or in the lungs (Pulmonary Embolism – PE). The latter can be very serious, even fatal. Following surgery patients are given injections of a heparin based substance to prevent clot formation. They are also provided with compression stockings and mechanical foot pumps which encourage blood flow through the circulatory system. Most importantly, patients are encouraged to regain mobility as quickly as possible so as to prevent clot development.
The new femoral head (the ball of the ball and socket joint) is smaller than the patient’s own and is therefore less stable/more likely to come out of the socket. As previously mentioned, patients are educated as to movements that should be avoided thus preventing dislocation (including bending down and twisting the hip). Nonetheless, dislocations can still occur.
The rate of dislocation varies but is generally quoted as occurring in 1-4% of patients undergoing joint replacement surgery.
None of Mr Hartwright’s patients have suffered with a dislocation of their hip replacement.
When the new hip is implanted, the surgeon must assess the “tension” of the tissues. If the ball is very loose in the socket the hip is more likely to dislocate. If the ball is too tight in the socket, movements of the joint may be stiff. In an effort to establish the correct “tension”, it sometimes happens that the overall length of the leg is altered (normally the leg length is increased).
Usually, any difference in leg length is not noticed by the patient but if it is noticeable (normally a discrepancy of ?2cm) then a heal raise can be placed in the other shoe to offset this inequality.
There are many other potential risks but the above probably represent the most important and certainly most asked about.