Orthopedics

KNEE REPLACEMENT SURGERY
The Normal Knee

This is a hinge joint. It is lined by articular cartilage and has two fibro-cartilage structures (menisci) which lead to enhanced stability, transfer of joint forces and nutrition of the joint. Stability is further achieved by the cruciate ligaments in the centre and collateral ligaments at the periphery of the joint, as well as surrounding muscles.

The Diseased Knee

Wear of the articular cartilage occurs because of a natural aging process or secondary to an underlying disease or trauma. The common conditions leading to joint degeneration are Osteoarthritis and Rheumatoid Arthritis.

Cartilage is not seen on an x-ray. A space will be seen instead between the femur and tibia. Wearing of the cartilage will present with a loss of this natural space, when viewed on xray.

Knee surgery in London may be needed if a worn joint presents with pain, swelling and restricted movement. There may also be a feeling of instability and noticeable deformity.

KNEE REPLACEMENT PROCEDURE
The Surgical Procedure

This involves replacing part or all of the joint surfaces of the knee.

Types of Implants

Implants are used to replace part of joint involved in the diseased process.

Indications for Surgery

Pain which is present at rest and at night that does not respond to simple analgesia. Instability, stiffness of the knee as well as progressive deformity are also indications.

Benefits of Surgery

Improvement in pain, function as well as deformity

Expected Surgical Outcome
  • Commence exercises on day of surgery if possible.
  • Mobilise 1st post-operative day.
  • Home at day 4/5.
  • Stair climbing by home discharge.
  • At least three months full recovery for total knee replacement and eight weeks for partial knee replacement.
  • At least pre-operative range of motion, but painfree.
Complications of Surgery
  • Infection
  • Deep vein thrombosis/ Pulmonary Embolism
  • Numbness lateral aspect scar.
  • Neurovascular injury
  • Fracture
  • Loosening
  • Anterior knee pain and scar tenderness.
RISK OF KNEE REPLACEMENT SURGERY
Infection

The risk is 1-2%. May be doubled in diabetic patients and those that are obese. The risk of MRSA is much less than this. Antibiotics are given to prevent infection before and after surgery. Most infection respond to antibiotics.

Blood clots (deep vein thrombosis)

This risk is also 1-2%. This is prevented by keeping you well hydrated, giving you special stockings to wear and also medicine to thin your blood throughout your hospital stay. Getting out of bed as soon as possible after surgery also minimises this risk. Rarely the blood clot can dislodge from the leg veins and travel to the lung with serious consequences. (Pulmonary embolism).

Fracture

Some force is required to attach the prosthesis to your bone. In doing so there is a risk of bone fracture. Any fracture occurring during surgery will be treated right away. This does not cause any long term problems but may prolong your requirement crutches post operatively.

Nerve and Artery Damage

Important nerves and arteries are in close proximity to the knee joint and hence are at risk of trauma during surgery. The risk to these structures is usually small.

Limp

Though most patients limp after surgery, this usually improves. The limp is due to weakness of the muscles around the knee as they have been cut during surgery. As they heal, the limp improves. In patients who were unable to exercise before surgery, the muscle becomes very weak. Following surgery a full recovery may not be possible.

Loosening

Most prostheses should last 10- 15 years. Many last beyond that if you keep your weight under control and avoiding activities that put excessive strain on the knee.

POST OPERATIVE CONSIDERATIONS
Post Operative Considerations of Knee Replacement Surgery

On returning to the ward following surgery you will have a drip (intravenous infusion) , a catheter, nasal tongs to give you oxygen and a device for self administration of analgesia. There may be a drain in situ to collect any blood collecting in your surgical wound.

Blood Transfusions

This is avoided wherever possible though will sometimes be necessary.

Physiotherapy

Generally begins the day of surgery. This involves exercises both in and out of the bed as well as mobilisation. Mobilisation initially commences with a Zimmer frame before progressing to crutches and then to sticks. On discharge you may be mobilising with sticks or independently.

Exercises will be advised that you need to perform regularly on discharge.

Not all surgical packages include the fees for crutches and walking aids. Check with the hospital prior to admission.

Occupational Therapy

You will see the Occupational therapist who will recommend equipment to assist you with your day to day activities. This may include raised toilet seat, grasper, long handled shoehorn, bath seat etc.

Special Advice Following Knee Replacement Surgery

It takes at least three months to make a recovery following Total Knee Replacement Surgery

Kneeling: Do not kneel on your knee post operatively for at least three months.

Driving: This can commence once you can bend your knee more than 90 degrees and are sufficiently pain free to perform an emergency stop safely.

Exercises: It is very important that you perform the exercises advised by the Physiotherapist regularly. These are designed to strengthen the muscles around the knee and improve the range of movement.

Pre-operative considerations of Knee Replacement Surgery

Prior to surgery you will require:- blood tests and xrays of your knee. You may also require a chest xray and echocardiogram (ECG).

A urine sample will also be taken to exclude any underlying infection and you will be checked to ensure you are not a carrier for MRSA. (Methicillin Resistant Staphylococcus Aureus)

Special Considerations

Patients on Aspirin or other anticoagulants such as Warfarin and Clopidogrel need to cease taking the medication 5-7 prior to surgery. Advice will be given as to whether other medication needs to be substituted. Blood tests will be required just before surgery to ensure clotting factors are back to normal.

If there is any sign of infection such as a skin rash, tooth abscess or dental decay, chest infection, these need to be treated prior to surgery as they are a potential source of infection for your prosthesis

If you are a smoker you are at an increased risk of a chest infection following your procedure. If possible reduce or give up smoking prior to the operation. Post operative knee function is determined by pre-operative function. Hence the more you exercise and strengthen your muscles prior to surgery, the better your outcome will be after surgery M

HIP REPLACEMENT SURGERY
The Normal Hip

This is composed of a ball (femoral head) and socket (acetabulum) joint. Both sides of the joint are lined with articular cartilage.

The most common disease affecting the hip joint is osteoarthritis. This is essentially a wearing away of the articular cartilage, to expose underlying bone. This may come on primarily or secondary to preceding trauma or deformity. Other diseases such as Rheumatoid Arthritis and other inflammatory diseases can also affect the hip.

When the articular cartilage is worn, you will experience symptoms of pain in the groin or knee as well as stiffness and restriction of movement

The Diseased Hip
Minimally Invasive Hip Surgery

Minimally invasive hip surgery in London involves inserting the hip prosthesis of choice through an incision generally less than 10cms. However depending on the patient’s body habitus, a >10cm incision may still qualify as minimally invasive. There is less muscle cutting and more muscle splitting in a minimally invasive approach compared with a conventional approach.

With a minimally invasive approach there is less blood loss, faster recovery and a more cosmetic scar.

Not all patients are suitable for this approach however. Suitability for this approach will be discussed during the consultation.

WHAT IS HIP REPLACEMENT

This is a surgical procedure that involves replacing the joint surfaces of the hip. The replacement of the femoral joint surface may involve a prosthesis with a stem that is placed deep in the femur (conventional hip replacement) or sits on its surface (hip resurfacing). The acetabular joint surface is also replaced with these procedures.

There are other considerations with Joint Replacement such as what keeps the prosthesis in the bone and what the ball and socket are made of.

Prostheses can be fixed on/in the bone with or without cement. The ball and socket can me made up of metal on both sides, metal on the ball side with polyethylene on the socket, ceramic on both sides or ceramic on the ball side and polyethylene on the socket side.Shape and condition of the bone as well as age of the patient will affect these variables.

Indications for Surgery

Pain in the hip or knee at rest and/or at night that does not respond to painkillers and modification of activity, in association with changes in the hip on x-ray. Marked stiffness of the joint is also an indication.

Age is not a determinant factor. If you are medically well enough to tolerate an anaesthetic, you can have a hip replacement.

Benefits of Surgery

The benefits from surgery are the relief of pain and improvement in range of hip motion.

The hip replacement can be inserted though a conventional or minimally invasive approach. Your suitability for minimally invasive surgery will be discussed at your consultation.

RISK OF HIP REPLACEMENT SURGERY
Infection

The risk is 1-2%. May be doubled in diabetic patients and those that are obese. The risk of MRSA is much less than this. Antibiotics are given to prevent infection before and after surgery. Most infection respond to antibiotics.

Blood clots (deep vein thrombosis)

This risk is also 1-2%. This is prevented by keeping you well hydrated, giving you special stockings to wear and also an injection to thin your blood throughout your hospital stay. Getting out of bed as soon as possible after surgery also minimises this risk. Rarely the blood clot can dislodge from the leg veins and travel to the lung with serious consequences. (Pulmonary embolism).

Dislocation

This should not occur if instructions given by the physiotherapist and nurses are followed. The risk is small, though greatest in the first three months after surgery.

Leg length discrepancy

Though every effort is made to keep your legs of equal length, discrepancies can occur. If your leg was very short before surgery, it may not be possible to make both legs of equal length. The difference in length if present, is easily corrected with an insert in the shoe.

Fracture

Prostheses that are held in the bone without cement have to be wedged in place. In doing so there is a risk of bone fracture. This does not cause any long term problems but may require you to use crutches post operatively, for six to twelve weeks.

Nerve and Artery Damage

Important nerves and arteries are in close proximity to the hip joint and hence are at risk of trauma during surgery. The risk to these structures is usually small.

Limp

Though most patients limp after surgery, this usually improves. The limp is due to weakness of the muscles around the hip as they have been cut during surgery. As they heal, the limp improves. In patients who were unable to exercise before surgery, the muscle becomes very weak. Following surgery a full recovery may not be possible.

Loosening

Most prostheses should last 10-15 years. Many last beyond that.

PRE-OPERATIVECONSIDERATIONS
Pre-operative considerations of Hip Replacement Surgery

Prior to surgery you will require:- blood tests and x-rays of your hip. You may also require a chest x-ray, echocardiogram (ECG) and tests relating to any underlying medical conditions.

A urine sample will also be taken to exclude any underlying infection and you will be checked to ensure you are not a carrier for MRSA. (Methicillin Resistant Staphylococcus Aureus)

Special Considerations

Patients on Aspirin or other anticoagulants such as Warfarin and Clopidogrel need to cease taking the medication 5-7 prior to surgery. Other medication may need to be substituted and you wil be advised accordingly. Blood tests will be required just before surgery to ensure clotting factors are back to normal.

If there is any sign of infection such as a skin rash, tooth abscess or dental decay, chest infection, these need to be treated prior to surgery as they are a potential source of infection for your prosthesis.

If you are a smoker you are at an increased risk of a chest infection following your procedure. If possible reduce or give up smoking prior to the operation

Post operative function is determined by pre-operative function. Hence the more you exercise and strengthen your muscles prior to surgery, the better your outcome will be after surgery!

You will have the opportunity to discuss your anaesthetic with the anaesthetist prior to the procedure.

POST-OPERATIVE CONSIDERATIONS

On returning to the ward following surgery you will have a drip (intravenous infusion) , possibly a catheter, nasal tongs to give you oxygen and a device for self administration of analgesia. There may be a drain in situ to collect any blood collecting in your surgical wound.

Blood Transfusions

This is avoided wherever possible. During surgery whenever possible your blood will be collected, filtered and transfused to you. This minimises the need for a blood transfusion from someone else.

Physiotherapy

This follows the Enhanced Recovery protocol and begins on the day of surgery. Physiotherapy involves exercises both in and out of the bed as well as mobilisation. Mobilisation commences with a Zimmer frame before progressing to crutches and then to sticks. On discharge you may be mobilising with sticks or independently. Aim is to be discharged home around 4 days post op.

Exercises will be advised that you need to perform regularly on discharge.

Not all surgical packages include the fees for crutches and walking aids. Check with the hospital prior to admission.

Occupational Therapy

You will see the Occupational therapist who will recommend equipment to assist you with your day to day activities. This may include raised toilet seat, grasper, long handled shoehorn, bath seat etc.

Special Precautions to prevent hip dislocation

Care should be taken in the first three months after surgery to allow the muscles around the hip to heal and hence reduce the risk of dislocation. These will be shown to you prior to discharge but essentially involves avoiding crossing your legs, flexing the hip beyond 90 degrees and avoiding any twisting movements.

Movements to avoid:

1. Crossing of legs, when sitting or lying. Place a pillow between legs at night to prevent you doing this whilst sleeping. If you need to lie on your side (try not to do this for six weeks!), lie with the operated leg down. This will prevent crossing of operated leg.

2. Twisting or pivoting movements. This will lead to excessive tension on muscles trying to heal post surgery. Poor healing of hip muscles will increase the risk of dislocation.

3. Bending hip more than 90 degrees. To prevent this, do not bring operated leg up towards body or attempt to bend forward such that your hand can reach below your knee.