Knee Arthritis and Knee Joint Replacement

Knee arthritis is the end result of many processes affecting the knee joint and involves loss of joint cartilage with resulting pain, stiffness and deformity.
Usually affecting patients over 60 years of age, it can reach an advanced stage at an earlier age.
Some common causes include: Inflammatory (eg rheumatoid, psoriasis), crystal (gout), previous fractures or deformity of the bones, following meniscal removal, and simple old age.
Treatment is based on the stage of the condition, patients age and activities, and in a simplified form takes the form of a ladder starting with simple therapy and ending in major surgery in the form of knee joint replacement for advanced end stage arthritis.
Activity modification, painkillers, walking sticks, physiotherapy, injections including corticosteroids and hyaluronic acid ( synvisc, durolane or ostenil ) if appropriate, and keyhole surgery ( knee washout and debridement ) are some of the treatment methods with low complications and risks. These are alternatives to knee replacement surgery which is considered a last resort and is indicated for end stage severe arthritis primarily.

Knee Joint Replacement is the final surgical remedy and may be partial for certain patterns of arthritis, or complete. It is a major procedure, and does carry some important risks. It is a very successful procedure in the vast majority.
The worn out knee joint is replaced with a metal and plastic implant commonly cemented to the bones. This may be a partial or full knee replacement, depending on the pattern of wear seen on X-rays, and symptoms experienced by the individual.

The procedure (knee joint replacement) is now done routinely through less invasive exposures -Minimally Invasive TKR- than were previously used (average skin incision 10-12cm), and patients on average stay less than 2 days in hospital. Knee replacement recovery time takes place over a matter of many weeks however.
Implant technology and materials used are in continuous development and continue to improve.
Standard implants are composed of a highly polished metal alloy with stainless steel as its main constituent. Other metals are also part of the mix but in lesser volumes. An ultra high molecular weight polyethylene (plastic) insert provides the bearing interface between the metal components. Bone cement is used to bond the implants to the bones.

Precise surgical technique is important for success. Implants in correct alignment survive for longer periods than those in mal-alignment.
90% of implants survive well over 10 years or more.
An Audit of Knee Replacements performed by Mr Siddiqui revealed over 90% to be perfectly aligned, which is similar to what is obtained through computer and robot assisted procedures. Average length of stay in hospital <2 days,
Complications including infection, DVT, Pulmonary embolus, stiffness, can and do occur in up to 1% of cases and are mitigated with blood thinners, intra-operative antibiotics, and post operative physiotherapy & exercises.
Some residual pain after a knee replacement is normal and patients should not expect 100% pain relief.

Knee joint replacement recovery time is different between a partial knee and full knee replacement.
Recovery from a partial knee replacement is quicker than a full knee replacement, but both follow similar healing times.
Typical recovery after knee replacement is as follows:
Patients may only need to stay in 1 night on average
A period of 6 weeks or so will be in moderate discomfort. It is important in this stage to focus on keeping swelling down (rest and ice at regular intervals) and maintaining and improving the range of movement with regular exercise.
A balance between not doing too much and not doing enough has to be arrived at in order to get the best results from surgery.
Physiotherapists will usually work with patients during this period according to their progress.
At 3 months the knee will begin to feel a lot better than before the surgery in the majority of patients
At 6-12 months it will achieve its final function and this will remain the case in the majority.
Driving and embarking upon flights is permitted after 6 weeks
Kneeling may be uncomfortable following knee replacement.

The implants and techniques in present day knee joint replacement use have resulted in 90% of implants surviving beyond 10 years and they can even last for 20-30 years in a lot of patients
When they do fail, it is usually the bone that dissolves around the implant which renders it loose.
Once this happens, a revision procedure using special implants and performed by specialist revision knee surgeons may become necessary.