Fracture Risk Increases After Total Knee Replacement

Researchers from Molndal, Sweden have published initial results of a fracture risk study based on the analysis of data gathered from medical records from 1987-2002, which covered Swedish citizens who were born between 1902-1952.

The research

Over 3,000 patients qualified for the study as they had both a total knee replacement (TKR) done and had sustained a hip fracture.

The hazard ratio (HR) in patients who were diagnosed with osteoarthritis (OA) of the knee and who had sustained a hip fracture before a TKR averaged around 0.58, and the hazard ratio during the 10 years after surgery had increased to average around 1.04. The HR in patients who were diagnosed with osteoarthritis (OA) of the knee and who had developed a vertebral fracture before a TKR averaged around 0.55, and the hazard ratio during the 10 years after surgery had increased to average around 1.19.

These values still remained the same even when adjustments were done to include other factors such as age, gender, latitude and calendar year values.

Summary of the findings

A reasoning behind these finding could be that OA is linked with increased bone mass and there's reduced physical activity due to pain experienced in the knee(s). This would result in less activities being performed which would otherwise increase the risk of sustaining an injury which could result in a fracture. The increased risk of sustaining a fracture, in the 10 years following TKR, would then be explained by a reduction in pain and increased mobility of the patient.

The clinical significance

These findings suggest that further research needs to be done in order to further understand this increased risk of possible fractures, seeing that thousands of knee replacements are done annually worldwide.

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Complications of hip fractures

Hip fractures can cause great morbidity and increase a person's mortality risk, too. In 50% of cases of hip fractures, patients won't be able to regain their ability to live independently again.

Hip fractures can cause one to become immobile for a long period of time and this can result in further complications, such as:

• Bedsores - these can become infected and lead to septicaemia.
• Pneumonia - due to immobility, mucous builds up in the airways which is an excellent breeding ground for bacteria.
• Urinary tract infections - prolonged catheter placement after surgery can lead to this.
• Thromboembolic events - blood clots can develop in the deep venous system of the lower legs, called deep venous thrombosis or DVT. These clots can cause further complications if they detach, thus becoming an embolus, and travel to and cause an obstruction in the pulmonary veins. This causes decreased blood flow to the lungs and may be fatal.
• Loss of muscle mass - immobility leads to muscle atrophy, which causes weakness in the body and therefore increases the risk of falls and further injury.

Osteoarthritis - The Most Common Form Of Arthritis

Osteoarthritis (OA) is the most common form of arthritis and it affects millions of people worldwide. It occurs over a relatively long period of time, when there's deterioration or wearing down of the protective cartilage which is found on the ends of bones.

The smooth and slick surface of this cartilage eventually wears down and one is left with bony surfaces rubbing against each other. This then leads to inflammation and pain which is associated with OA. 

Even though OA can cause damage to any joint in the body, it seems that the most involved joints are those of the spine, hands, hips and knees.

Risk factors

• Advancing age is a risk factor for developing OA.
• Gender - females are more likely that males to develop OA and the reason for this is unknown.
• Genetic factors - there seems to be that certain people inherit a tendency to develop OA.
• Obesity - having to carry extra weight results in increased stress being applied to weight-bearing joints such as the hips and knees. Obesity is also associated with fat tissue producing proteins which can cause inflammation in and around the joints. 
• Injuries to the joints - joint injuries can be sustained due to sporting activities or accidents and these events can speed up the progression to OA, even if the incidents occurred years before and had seemingly healed.
• Bone deformities - the risk of OA is increased in patients with malaligned bones, defective cartilage or malformed joints.

Signs and symptoms

OA develops slowly and becomes worse over time. Signs and symptoms of this condition could include the following:

• Pain - can occur during or after moving the affected limb.
• Stiffness - this may be more pronounced when getting up in the morning or after a period of being inactive. Stiffness due to OA tends to improve, but not resolve, as the day goes on.
• Tenderness - applying light pressure on the affected joint may elicit tenderness.
• Grating sensation - 'crepitus' is when one feels or hears a grating sensation when moving the affected joint.
• Decreased flexibility - there's loss of flexibility with OA and patients can't seem to make use of the full range of motion of the affected joint.
• Bone spurs - these are extra pieces of bone which form around the affected joint due to chronic inflammation.

READ Pain Relief | How to Effectively Avoid Hip Pain

Complications 

Diagnosis

OA is usually diagnosed based on clinical findings. X-rays and MRI's are performed to help determine the extent of damage to the affected joint and would help in determining the correct form of management for the patient.

Treatment

The management of OA depends on the severity of the condition. In most cases, medications such as paracetamol or anti-inflammatories as well as physical therapy are enough to help alleviate symptoms. If the OA is so severe that it affects the patient's quality of life or conservative therapies are no longer effective, then surgical intervention may be necessary.