Knee osteoarthritis

What is knee osteoarthritis?

Knee osteoarthritis is a degenerative joint condition. It is a “wear and tear” process involving the joint cartilage. As the wear process progresses it produces abnormal joint loading which in turn leads to the gradual onset of pain, deformity and loss of function.

What can cause it?

Many factors can contribute to knee osteoarthritis:

  • Age. With increasing age the muscles which provide support to the joint weaken. This places greater forces across the joint and can accelerate the degenerative process leading to osteoarthritis.
  • Weight. An increased body mass index places more stress across the joint and therefore can lead to osteoarthritis. Likewise in such situations, a joint replacement will loosen and fail quicker due to the increased forces placed across it.
  • Pre-existing joint conditions. Conditions such as Rheumatoid arthritis, psoriatic arthritis and gout.
  • Previous injury or surgery. A history of significant trauma. This may involve previous soft tissue or bony injuries. Previous extensive soft tissue or bony surgery can also lead to osteoarthritis.
  • Lifestyle. Activities which frequently place large twisting loads across the knee can also cause osteoarthritis.
  • Family history. Sometimes osteoarthritis can run in families.
  • Gender. Osteoarthritis of the knee is slightly more common in females.

What are the symptoms and signs?

There is an associated broad spectrum of symptoms ranging from a low-grade activity-related, dull ache through to a more debilitating, constant ache which can result in sleep disturbance, pain at rest along with significant compromise of activities of daily living. Often one’s quality of life is poor as a result of the ongoing symptoms. Symptom progression can often be monitored by a careful assessment of one’s painkiller requirement and walking distance. Associated mechanical symptoms may include stiffness, swelling, locking, clicking and giving way.

Objective signs

In my office, this may include:
an associated limp along with muscle wasting and deformity in and around the joint, suggestive of long-standing joint dysfunction. There may be significant joint line tenderness along with a reduced range of movement. A meticulous examination of the soft tissue around the joint along with the nerve and blood supply to the limb will also be performed.


What investigations may be required?

Plain radiograph (x-ray)

Weight-bearing plain radiographs are a quick and effective way of confirming arthritis in a joint. In the early stages when there is inflammation with no damage to the joint they may be normal. Most people, however, present when there is some structural damage.

The following are features of arthritis on a plain radiograph:

  • Decreased joint space
  • Subchondral sclerosis
  • Subchondral cysts
  • Osteophytes
  • Deformity (change in knee shape)

MRI provides excellent high definition static images. It is useful in preoperative planning and to exclude any other pathology in the knee. It is also useful in monitoring healing.

MRI is particularly useful in assessing:

  • Cartilage loss
  • Reactive bone changes
  • Effusion
  • Synovitis
  • Ligament damage
  • Tendon pathology (tenosynovitis, tendon tears)
  • Any other pathology

CT images give excellent information on the bone structure and are superior to plain radiography in that respect.

CT is particularly useful in the following cases:

  • 3D image reconstruction
  • Preoperative planning
  • Evaluating the joint in the presence of surgical hardware ie screws & plates.
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Can the problem get worse?

The problem can certainly progress and therefore careful clinical and x-ray monitoring is important.

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Potential complications

It should be borne in mind that complications may result from a condition with or without surgery. Complications of non-operative treatment include worsening pain, increased stiffness, increasing deformity, adjacent joint disease, pain elsewhere, for example in the ankle, hip or lower back (due to abnormal gait and compensatory mechanisms). Complications can occur with any type of surgery.

Potential general complications: risks and complications of anaesthesia, bleeding, infection, blood clots, the need for further surgery, persistent pain, complex regional pain syndrome and wound healing problems, genito-urinary complications and cardiovascular complications.

Potential complications which are specific to the surgery mentioned above include nerve damage/foot drop, intraoperative fracture, stiffness, instability, loosening, wear, the need for revision surgery and non-resolution of symptoms, partial resolution of symptoms, leg length discrepancy.


There is no one treatment that has a reliably successful, quick and easy cure for arthritis. Therefore researchers and doctors are constantly looking for new and better ways of treating arthritis. Many treatments have come into fashion and then gone away over the years once results had shown that the initial promise was premature and misplaced.

At The London Hip and Knee Clinic we do not promote or discourage new treatment options for arthritis. We would, however, advise a cautious approach to relatively untested treatment modalities with little or no evidence to back their use. Patients undergo these treatments at their own risk.


Non-surgical management

Non-surgical management of knee arthritis aims to relieve pain and return to full activity including sports whenever possible. It is likely to be most effective in the early stages of the condition.

It should always be the first line of treatment. Options include:

Activity modification

A period of rest from sports and exercise that bring on symptoms. Avoiding high impact activities with lots of turning and twisting.

Insoles & orthotics

The use of a supportive shoe with custom insoles can help correct alignment of the knee and therefore balance the forces across the knee.

Non steroidal anti-inflammatories.

The use of non-steroidal anti-inflammatory drugs (NSAIDs) can decrease discomfort in patients with knee arthritis by reducing inflammation in the joint.


The use of paracetamol and other painkillers can help reduce pain levels.


Physiotherapy works by strengthening muscles around not only the joint but the whole kinetic chain. Results are variable with arthritis and depend really on the severity of the disease. In a very stiff and damaged joint, physiotherapy may make your symptoms worse. Your surgeon will guide you.

Walking aids

The use of a walking stick or cane to reduce the forces going across the damaged joint.

Weight loss

Weight loss can relieve the pressure on painful damaged joints.

Dietary suppliments

Dietary supplements are increasingly popular with people who have arthritis. The cartilage found in joints, normally contains glucosamine and chondroitin. It is thought that taking supplements of these natural ingredients may help to improve the health of damaged cartilage. Research has provided mixed results but on the whole suggests that glucosamine sulphate is more likely to be helpful than glucosamine hydrochloride. If you are thinking of taking glucosamine, we suggest taking 1,500 mg per day of glucosamine sulphate. If you notice no improvement in your symptoms after 3 months then you should probably discontinue it. If you do find it improves your symptoms then you need to continue taking the supplements. There is no extra benefit in taking glucosamine and chondroitin. Remember that supplements also have side effects and it is advisable to discuss with your GP before starting any new treatment.


Surgical management

This decision to undergo surgery a very individualised one. Surgery is to improve pain, alignment and function. As a rule, it is always a last resort once conservative measures have been exhausted.

Based on your unique clinical picture your surgeon will advise you on the best type of surgery available to suit your individualised requirements. Options include:

Knee arthroscopy (Keyhole knee surgery)

Arthroscopic washout and debridement may work in specific cases where there are defined soft tissue injuries or loose bodies (Osteocartilaginous debris) causing mechanical symptoms. Small isolated areas of cartilage loss can also be smoothened out or micro-fractured. For widespread advanced arthritis, keyhole techniques have a very limited role.

Click here for more information on knee arthroscopy surgery.


Re-alignment osteotomy which is a joint-preserving procedure may be beneficial in younger patients. This involves making a cut across the shin bone and opening out a wedge in such a way that it offloads the arthritic area of the joint.

Total knee replacement surgery

This involves replacing the knee joint i.e. the end of the thigh bone and the top of the shin bone. Precision cuts are performed to maintain as much natural bone and soft tissue constraints as possible. The state of the art high-performance components are then cemented in place. Prior to this, a thorough intraoperative check is performed to check that the knee is balanced, stabilised and is moving well.

There are many types of total knee replacements. Your surgeon will discuss which option is best for you and at all times reference will be made to the national joint registry to ensure that the selected prosthesis has a proven track record.

Click here for more information on total knee replacement surgery and joint preservation and realignment surgery

Custom made cutting blocks

This involves obtaining a scan of your knee from which cutting blocks are then manufactured unique to your anatomy.

Partial knee replacement

The knee consists of three compartments. The inner compartment is deeper and therefore more loads go through it. If there is isolated osteoarthritis in this compartment then it may be possible just to replace this. In selected patients, unicompartmental knee replacements recover quicker and have a better function. Research, however, suggests that a unicompartmental knee replacement is more likely to be revised (Redone) than a total knee replacement which is more predictable.

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Postoperative period and recovery

Remember that below is a guide to recovery and that everyone heals at different rates and some people do take longer. Use this information to help you understand your condition, possible treatment and recovery. The timeframes given below are a minimum, it is important that you appreciate this when considering surgery as your healing and recovery may take longer.

After your operation, a routine enhanced programme of recovery will commence. The main parallel work streams of this programme are as follows:


Mobilisation is commenced on Day One. Gradually there is an increase in the frequency of transfers in and out of bed. This then progresses onto stairs and mobilisation to the toilet/shower and back. Before discharge, the patient is well rehearsed in the exercise routine and the knee should bend to at least ninety degrees. It is extremely important to remain well motivated and perform your exercises after discharge to fully optimise the range of motion of the newly replaced knee.

Occupational therapy

Will focus more on activities of daily living, functional transfers and adaptation of the home environment.

Pain control

During the operation, spinal anaesthesia with local infiltration of anaesthetic around the hip is used. After the operation regular oral medication is then used. Ask for extra if required. Before discharge required prescriptions are provided.

Wound therapy

It is perfectly ok to experience an ooze from the wound especially as one mobilises. Your dressing may require changing. Before discharge, the wound should be dry and arrangements will be in place for staple removal by your practice nurse.

Nutrition, fluids and excretion

Immediately after the operation intravenous (directly into the veins) fluids are given. Medications such as routine antibiotics are also given via this route. Urine output is carefully monitored. A bedside commode may be needed during the first postoperative day.

Normal diet is introduced as soon as possible. The urine catheter is removed once mobile. Bowel habit should also return to normal before discharge.

Personal Hygiene

On the first morning after the operation ablutions are performed at the bedside. Showering is then gradually introduced – at first with assistance and then independently.


When should I stop using a walking aid?

Stop using a stick once you feel comfortable to do so. Do not worry if this takes a bit longer since we all recover at different rates. Your surgeon will advise you at your follow up appointment.

How much should I walk?

Walk as far as your general health permits you to do so. If there are any concerns with shortness of breath or dizziness then stop and seek help. It will take a while before you get used to the knee replacement so increase your walking distance gradually.

How far can I walk?

Following a routine primary total hip replacement, you should be able to walk the same distance as before the hip became symptomatic. Ensure that you don’t become tired, breathless or dizzy.

My knee remains swollen and warm - is this normal?

A total knee replacement can remain slightly swollen and warm for up to many months after the operation. This is often part of the normal healing process. If the changes are sudden or associated with a temperature or a discharge from the wound consult your surgeon at once since this could represent infection.

Infection caught early often requires a joint washout with an exchange of any removable parts of the knee. Delayed or established infection often involves a staged procedure to help eradicate the bug.

Why does my knee feel stiff?

In the early stages, the knee will try and stiffen up and scar down to its preoperative stage. Many soft tissue releases are performed during the operation to balance the knee. These releases will also begin to scar down. The best way to prevent this is to continue diligently with the physiotherapy programme.

Remain motivated and enthusiastic about the physiotherapy since at this stage it a crucial part of the recovery programme. If there are any setbacks in the first few weeks the scar tissue may consolidate and lead to a stiff knee. Such cases may require a manipulation under anaesthesia.

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