What are the risks and complications associated with this surgery?
As with any major surgery, there are some potential risks after hip replacement surgery. Risks which a patient should be aware of are:
1. Deep Venous Thrombosis (clot formation in the leg veins)
2. Infection
3. Dislocation
Deep Venous Thrombosis (DVT)
DVT may occur after any major surgery on the lower limbs or pelvis including joint replacement surgery. DVT as such may not cause any symptoms but in a small proportion of patients (less than 1%) the clot can dislodge from the leg veins and cause blockage of major blood vessels in the lungs (pulmonary embolism) or in the brain (cerebral embolism). In such an eventuality patients need supportive therapy and intensive monitoring in the intensive care. Patients with previous history of DVT, obesity and smokers are at a higher risk of getting DVT.
After any such surgery, therefore all efforts are taken to minimize the risk of DVT. Most surgeons may use one or more of the following methods:
1. Low molecular weight heparin (LMWH) – Blood thinning injections
2. Coumadin (Warfarin) or Aspirin – Blood thinning tablets
3. Elastic stocking – TED stockings
4. Intermittent Pneumatic Compression pumps – Flowtron pump
5. Early mobilization – getting a patient out of bed as soon as possible
Patients who develop clots (established DVT) in the post-op period will need heparin injections for a few days followed by warfarin tablets for about 3 months post-op.
Infection
As with any major surgery, there is a potential risk of infection with any joint replacement surgery. The overall risk of infection with hip replacement surgery is quite low (about 1%). Every effort is made to prevent infection after joint replacement surgery.
How does one reduce the chances of infection after hip replacement surgery?
Every patient is assessed carefully before surgery for risk of infection. Patients with pre-existing diabetes have a higher chance of infection, and need good control of their blood sugar levels. Patients with urinary tract infection, bad teeth or with any other infection in the body should wait until their infection is treated and cleared. Patients are given higher antibiotics before and immediately after surgery as a precautionary measure (prophylactic antibiotics). These surgeries are performed in clean air operating theatres.
What happens if a patient if a patient develops infection after hip replacement?
The treatment of infection after knee replacement surgery depends on whether the infection is superficial or deep.
Most superficial infections (redness of wound) can be treated with a prolonged course of antibiotics (6-8 weeks) given initially intravenously orally later. Deep infections which present early (up to 3-4 weeks after surgery) need urgent surgery in form of arthrotomy and wash out (opening of the wound and wash-out of the joint with normal saline) and prolonged antibiotic therapy intravenously followed by oral antibiotics. When treated early, it is possible to retain the patients’ prosthesis and expect control of infection. Deep infections which present late (weeks or months after the surgery) may need two stage surgeries whereby the existing prosthesis is removed and a cement spacer is kept between cut bony surfaces (first stage), followed by intravenous antibiotics for about 6-8 weeks to achieve control of infection. Once the infection is under control, a new prosthesis can be implanted at a subsequent surgery (second stage). In some instances where the infection is difficult to control, it may be necessary to consider doing an excision arthroplasty (the infected implants are removed and the space between the bones is filled with muscles and soft tissues).
Dislocation
This implies that the femoral head comes out of the acetabular cup. The head can come out in the front of the joint (anterior dislocation) or behind the joint (posterior dislocation). The chance of getting a dislocation after hip replacement surgery is about 1-2%.
Treatment of dislocation involves closed reduction of the hip (pushing the head back manually without having to cut open the joint) under sedation or general anaesthetic. This is followed immobilization (rest) and use of a brace (external support) for a period of few weeks. Recurrent dislocation (repeated dislocations) may revision surgery (removing one or more components and replacing with a new component) after careful evaluation to assess the cause of dislocation.