Complications of total knee replacement

Complications ofTotal Knee Replacement

Vaishnavi Suresh Nair

The knee is one of the largest and most complex joints in

the body. The knee joins the thigh bone (femur) to the shin

bone (tibia). The smaller bone that runs alongside the tibia

(fibula) and the kneecap (patella) are the other bones that

make the knee joint.

Tendons connect the knee bones to the leg muscles that

move the knee joint. Ligaments join the knee bones and

provide stability to the knee:

•The anterior cruciate ligament prevents the femur from

sliding backward on the tibia (or the tibia sliding forward

on the femur).

•The posterior cruciate ligament prevents the femur

from sliding forward on the tibia (or the tibia from sliding

backward on the femur).

•The medial and lateral collateral ligaments prevent the

femur from sliding side to side.

Two C-shaped pieces of cartilage called the medial and

lateral menisci act as shock absorbers between the

femur and tibia.

Numerous bursae, or fluid-filled sacs, help the knee move

smoothly.

KNEE-ANATOMY

Nerves, Blood Vessels, and Lymphatics of the Knee and Leg

BLOOD SUPPLY & DRAINAGE:

•Popliteal artery

•Genicular arteries

•Anterior tibial artery

•Posterior tibial artery

•Fibular artery

•Lateral superior genicular vein

•Lateral inferior genicular vein

•Great saphenous vein

•Small saphenous vein

The lymph nodes

The popliteal fossa also contains a few lymph nodes.

Popliteal lymph nodes receive lymph from superficial and deep lymphatic vessels and the joint

capsule.

Superficial lymphatic vessels from the lateral side of the foot and leg accompany the small

saphenous vein to the popliteal nodes.

The deep lymphatic vessels follow along sides of the deep veins of the leg to the popliteal nodes. The

lymph from these nodes flows in the deep lymphatic vessels of the thigh to the deep inguinal nodes.

INNERVATION:

•Tibial nerve

•Common fibular (peroneal)

nerve

•Medial sural cutaneous nerve

•Lateral sural cutaneous nerve

Total knee replacement

• A total knee replacement is a surgical procedure whereby

the diseased knee joint is replaced with artificial material.

• During a total knee replacement, the end of the femur bone is

removed and replaced with a metal shell. The end of the lower leg

bone (tibia) is also removed and replaced with a channelled plastic

piece with a metal stem. Depending on the condition of the kneecap

portion of the knee joint, a plastic "button" may also be added under

the kneecap surface. The artificial components of a total knee

replacement are referred to as the prosthesis.

• In total knee replacement surgery, the posterior cruciate ligament is

either retained, sacrificed, or substituted by a polyethylene post.

Conditions that can be treated with knee replacement

•Knee replacement can be used to replace a knee joint affected by a range of conditions including Severe arthritis such as (osteoarthritis, rheumatic arthritis, traumatic arthritis•Ligament damage or infection that leads to severe osteoarthritis•Rheumatoid arthritis•Haemophilia•Crystal deposition diseases such as gout and ‘pseudo gout’•Avascular necrosis – death of bone following loss of blood supply•Bone dysplasia – disorders of the growth of bone.

Indications for Knee Replacement Surgery

•Total knee replacement may be recommended when other treatment options (e.g., weight loss, pain relievers) no

longer reduce knee pain and disability effectively. Symptoms of knee damage that may require knee replacement

surgery include the following:

•Knee pain that hinders walking, climbing stairs, or getting in and out of a chair

•Knee pain that interferes with sleep or does not subside with rest

•Inability to cope with side effects of pain relief medication

•Knee swelling that does not respond to treatment and that limits bending or straightening the knee

•Significant bowing in or out of the knee

Benefits of Knee Replacement Surgery

• Reduction of joint pain.• Increased mobility.• Correction of deformities.• Increased stability.

Knee Replacement Surgery

Total knee replacement surgery generally takes about 2 hours to perform. The procedure involves removing

damaged bone, tissue, and knee cartilage and fitting these three replacement pieces:

•Femoral component (metal piece that attaches to the thighbone)

•Tibial component (plastic and metal piece that attaches to the shinbone or tibia)

•Patellar component (plastic piece that replaces the kneecap or patella)

Types of Knee Replacement Surgery

There are several different kinds of total knee replacement surgery. In most cases, the orthopedic surgeon

determines which type of surgery is best for each individual patient.

Minimally invasive surgeryis a type of knee replacement performed using smaller incisions with less disruption of surrounding tissue. This

procedure is not used if there is considerable misalignment of the thigh and lower leg.

Bilateral total knee replacementinvolves replacing both knees at the same time. Candidates for this type of surgery must be in good overall health.

A one-week stay at an extended care facility is often necessary for recovery from bilateral total knee replacement.

Computer-assisted total knee replacement surgeryIt involves using computer technology to help better align the replacement joint. Better alignment may increase the

longevity of the prosthesis.

Anaesthesia

Two types of anesthesia may be used in knee replacement surgery. In some cases, general anesthesia is used

and in other cases, spinal or epidural anesthesia is used.

General anesthesia involves putting the patient to sleep so that he or she is unconscious during the surgery.

When spinal anesthesia is used, the patient is awake, but is numb from the waist down. The anesthesiologist and

surgeon determine which type of anesthesia to use after consulting with the patient and reviewing his or her

medical history.

COMPLICATIONS OF KNEE REPLACEMENT SURGERY:

Complications of total knee replacement (TKR) can be mainly divided into the following 3

categories:

•Complications specific to the operative procedure

•General perioperative complications (including complications of anaesthesia)

•Other medical complications (postoperative complications)

Complications From Anesthesia

SYMPTOMS INCLUDE:

•dizziness

•shivering

•sore throat

•aches and pains

•discomfort

•drowsiness

Possible complications from anaesthesia include heart

attack, stroke, pneumonia, and blood clots.

(It's important for the anaesthesiologist to be aware of the

patient’s medical history, especially past or current heart

and/or lung issues, before surgery.)

After knee replacement surgery, anticoagulants may be

used for a period of time to reduce the risk for blood clots.

Complications specific to knee replacement surgery

•injury to nerves or blood vessels in the leg

•loosening or dislocation of the prosthesis

•difference in leg length following the surgery

•stiffness in the joint

•pain that persists or worsens after surgery

•allergic reaction to the cement used to affix the prosthesis

Complications can interfere with full recovery of the replaced joint.

Blood Clots

Knee replacements are likely to cause blood clots (DVT). Typically, blood clots occur within two

weeks of surgery but they can take place within a few hours or even in the operating room.

Clots contained within the legs represent a relatively minor risk. However, a clot that dislodges and

travels through the body to the heart or lungs can cause serious health concerns and, in rare

instances, death.

To reduce the risk of clots after surgery, take blood-thinning medications such as warfarin

(Coumadin), heparin, or enoxaparin (Lovenox). Common preventative measures include support

stockings, lower leg exercises, calf pumps, or elevating your legs. All of these techniques help to increase circulation and prevent the formation of clots.

Infection

Patients with rheumatoid arthritis , diabetes , weakened immune system have a greater risk of

infection in the weeks following a procedure. ,an infection in another part of the body at the time of your

knee operation—in the mouth, kidneys, or prostate could lead to an infection in the knee, even months or years later.

In rare cases, infection can occur at the site of the incision or within the prosthesis. Risk for

infection in the prosthetic joint persists for the rest of the patient's life. To reduce this risk, some

patients who have undergone knee replacement surgery take preventive (prophylactic) antibiotics

before future surgical or dental procedures.

Complications from a Transfusion

Not everyone needs a blood transfusion during a TKR. But, if you do, there’s a tiny risk

• Incompatible blood transfusions

• haemolytic transfusion reaction, to the donor blood

Signs and symptoms of an adverse transfusion reaction usually occur within 24 hours and include hives, fever, chills, shortness of breath, and red urine

Prosthesis Problems/Implant Failure

An inherent risk with any joint replacement surgery is improper placement or a malfunction of the implant which can cause:

•Infection

•continued pain

•knee stiffness

•wear

•instability

•Loosening

•dislocation

Prosthetic joint infections are classified into three types based on the amount of time that has elapsed

from the surgery to the onset of infection:

Early infections occur within 3 months of surgery and are usually caused by microorganisms that

enter the body during the operation. People with these infections may suffer from a leaking wound,

fever, swelling and effusion around the implant.

Delayed infections can occur from 3 months to 12 months after the surgery and are also caused

by organisms entering the body during the surgery. The symptoms of these infections are usually

the same as those seen in early infections.

Late infections occur more than a year after surgery. These infections are usually haematogenus,

meaning they are acquired from another location in the body. Bacteria from other infections such

as a dental infection, pneumonia, skin infection or urinary tract infection can travel in the blood and

adhere to the prosthesis. To prevent these types of infections, doctors recommend that patients

with prostheses take antibiotics before any surgical procedure. In late infections, joint pain and

effusion are common symptoms. Sometimes, the joint is also inflamed, and sepsis may set in.

Artery Injuries

Because the major arteries of the leg are positioned directly behind the knee, there’s a slight risk that damage

could occur to these vessels. If damage does take place, a vascular surgeon can usually repair the arteries.

Nerve or Neurovascular Damage

Damage to the nerves is also uncommon. However, it is possible for the nerve or blood vessel that’s associated

with the muscles leading to the foot to experience numbness following a procedure. The problem usually

disappears after a few months as nerves and tissue heals.

Knee Stiffness and Loss of Motion in the Knee

In some cases, scar tissue or other complications diminish motion within the knee. This problem can often be

resolved with special exercises and/or physical therapy. Severe cases of stiffness, also called arthrofibrosis, may

require a follow-up procedure in order to break-up scar tissue or adjust the prosthesis inside the knee.

Instability of LigamentsWhen ligaments are cut, damaged or improperly balanced after surgery, the knee can become unstable. Since most

knee implants are intended to work with a patient’s existing ligaments, if they are damaged, the implant may not

move correctly. This can cause the knee to give way, usually from side to side. This typically improves over time after

the ligaments heal, but occasionally a knee brace may be required to prevent buckling after surgery.

Arthrofibrosis (Joint Stiffness)Patients who have knee replacement surgery are susceptible to significant joint stiffness. If the person is obese, has

diabetes or is slow to mobilize after surgery, it can worsen this condition. This usually happens when excessive scar

tissue builds up around the joint. Doctors treat this by anesthetizing the knee and manipulating it to break down the

scar tissue. When the scar tissue is extensive, another surgery may be required to remove it.

Extensor Mechanism DisruptionExtensor mechanism disruption is one of the most serious mechanical complications that can occur after knee

replacement. This occurs when the tendon attached to the patella moves away from the tibia during or after surgery.

When this happens, the knee cannot extend. Surgery is required to repair the tendon, and a tendon graft may be

required.

Patella Tracking ProblemsA healthy patella glides up and down in a groove over the femur. Sometimes the patella dislocates after surgery. This

is most commonly associated with patellas that have been resurfaced with a plastic button, which can cause the

patella to track differently or catch and “clunk” as it passes over the metal flange of the knee. In some cases, the

tracking problem is severe enough to warrant revision surgery.

Allergy to Metal Components

Occasionally, a patient suffers a reaction to the metal used in the artificial knee joint. The metal materials used in

implants are typically made from titanium or cobalt-chromium based alloy. Most likely, you will know if you have a

metal allergy. If that is the case, make sure to tell your surgeon about the allergy well before your surgery. If you

are unsure, take the time to discuss the topic with your surgeon or medical team.

Wound and Bleeding Complications

Typically, the sutures or staples used to close the wound are removed after about two weeks. In some cases,

however, wounds may be slow to heal and bleeding complications can occur for several days following surgery.

The hospital staff will monitor your wound during the time you are there. Blood thinners can contribute to

problems and, in some cases, the surgeon might need to re-open the wound and drain fluid. You could also

experience a Baker’s cyst, which is a build up of fluid behind the knee. This may require draining with a needle to

remove the fluid. In addition, if the skin does not heal properly, you might require a skin graft at the wound site.

Osteolysis

Osteolysis is a complication of knee replacement that occurs when particles are generated by the plastic pieces

of the implant. These particles activate the body’s defences, including white blood cells. The white blood cells

digest these foreign particles, but they also can digest bone. The result is bone damage and implant loosening.

This condition is more common in implants that are made of polyethylene. While this material allows for more

natural joint function, it is also more susceptible to wear. When severe bone loss occurs, the implant loosens

and revision surgery is required.

Some general complications that can arise as a result of the

surgery include:

• Stroke• DVT• Congestive heart failure• Hyperglycemia• Hemorrhage• Limping• scarring.• Cardiac arrhythmias

• Edema• Wound problems

Knee is inflamed and infected

after total knee replacement

surgery

Mortality

The risk of death from knee replacement is very low, but it does occur.

A 2010 study published in the Journal of Bone and Joint Surgery estimated the risk of mortality

to be 0.1 percent.

The risk is highest during the first month after surgery.

Prognosis

The results of a total knee replacement are often excellent. The operation relieves pain for most

people. Most people do not need help walking after they fully recover.

Most artificial knee joints last 10 to 15 years. Some last as long as 20 years before they loosen and

need to be replaced again.

• For an optimal outcome after total knee replacement surgery, it is important for patients to

continue in an outpatient physical-therapy program along with home exercises during the healing

process. Patients will be asked to continue exercising the muscles around the replaced joint to

prevent scarring (and contracture) and maintain muscle strength for the purposes of joint stability.

These exercises after surgery can reduce recovery time and lead to optimal strength and

stability.

• Patients also should watch for warning signs of infection, including abnormal redness, increasing

warmth, swelling, or unusual pain.

• Patients with joint replacements should alert their doctors and dentists that they have an artificial

joint.

• Future activities are generally limited to those that do not risk injuring the replaced joint.