Why does PAIN occur? Understand the Mechanism of Pain

Pain is an unpleasant and distressing physical sensation caused by disease or injury, which induces hurt and anxiety in those suffering from it.
There are many different manifestations of pain, ranging from short term (acute pain) to long term (chronic pain). Other classifications include pain in the internal organs (visceral pain), injured tissue (inflammatory pain), nerves (neuropathic pain), etc.

The reason for the occurrence of pain depends on the cause and kind of pain being experienced. In most cases, pain acts as a warning sign that the body has been afflicted by a disorder of some sort, which may have arisen due to internal sickness or external wounding. Acute pains are generally cured on their own through rest or simple medication. Chronic pains, on the other hand, are more complicated in nature and the treatment requires more elaborate diagnosis.

The mechanism of pain

Pain is an extremely personal and subjective experience and affects each individual to varying degrees. The pain signals, which can arise in any part of the body, travel through the spinal cord to the brain along thousands of specialized nerves and nerve fibres. In the brain, it is processed in the centres associated with anxiety, emotions, memory, appetite, etc. Signals and pain inputs are then returned from the brain to the spinal cord, which may heighten or diminish pain.

In some cases, pain may also be induced by damage to the brain and spinal cord, which happens after a stroke.
A constant barrage of pain signals may cause the cells at the end of nerve fibres to become over-sensitized. This is known as 'wind-up' and is one of the most common causes of chronic pain that occurs even though the root of the problem has been identified and treated.

The causes and effects of pain differ from case to case depending on the signals received by the brain and its interpretation. It affects the individual's day to day activities and if persistent, can also have a harmful impact on mental health and psychosis. Pain is always handled, diagnosed and treated differently in all patients by drawing out the best possible solution to the problem.





Why does PAIN occur? Understand the Mechanism of Pain

Knee is a hinge joint where the lower leg bone tibia meets the thigh bone femur. During osteoarthritis, cartilage or ligament defects and degenerative arthritis, knee replacement surgery is recommended world-wide to get relief from extreme pain. Knee replacement surgery, also known as knee arthroscopy, is a surgical procedure, in which the affected knee joint is replaced with synthetic material. The most likely candidates for total knee replacement are the patients with severe destruction of the knee joint coupled with progressive pain and impaired function.

Modern technological advances have made computer assisted knee replacement surgery extremely popular around the globe. In this surgery, the surgeon is assisted by a computer to remove the optimum amount and angle of the bone, which otherwise is done by inspecting manually. This is an excellent example of surgery through small incision and it eliminates the chances of human error. A perfect alignment and balance is achieved and hence longevity is also increased to 20 - 30 years. Knee replacement surgery is also specific to gender as the anatomy of male and female patients is different.

There are many types of knee replacements, most common being the total knee replacement or Total Knee Arthroplasty. In addition, there is partial knee replacement, bilateral knee replacement, revision knee replacement and knee arthroscopy.

In knee replacement surgery, the worn out surfaces of joints of knee are replaced with artificial implant of plastic and metal. The lower end of the femur bone is removed and replaced with a metal shell. The upper end of the lower leg bone (tibia) is also removed and replaced with a channelled plastic implant with a metal stem. A plastic ball is also added under the kneecap depending on its condition. These artificial components are commonly referred as prosthesis. The design of these highly flexible implants replicate knee, with the rotating knee replacement implants assist in backward and forward swing of the legs.

Patients whose knee joints have been damaged by either trauma or progressive arthritis should consider total knee replacement surgery. Post-surgical hospital stay after knee joint replacement is usually three to five days. The surgery has a very high success rate and shows dramatic improvement after a month. This improvement is most notable one month or more after surgery. The pain caused by the damaged joint is reduced significantly when the new gliding surface is constructed during surgery. Initially, patient will walk with the help of a walking aid until the knee is able to support full body weight. After six weeks, patient can walk comfortably with minimal assistance. Patients with artificial joints are prescribed to take antibiotics during the course of any elective invasive procedures including dental work. Physiotherapy is an essential part of rehabilitation and it will increase the muscle strength and patient can enjoy most activities, except running and jumping.

Knee Replacement

Knee replacement can be extremely painful. Previously, opioids or narcotics were administered for pain relief. But excessive addition of opioids is not exactly effective for controlling pain. 

Multimodal pain management has become an important part of the perioperative care of patients undergoing total joint replacement. The principle of multimodal therapy is to use interventions that target several different steps of the pain pathway, allowing more effective pain control with fewer side effects. Many different protocols have shown clinical benefit. The goal of this review is to provide a concise overview of the principles and results of multimodal pain management regimens as a practical guide for the management of joint arthroplasty patients.

Multimodal denotes administering two or more than two types of medications that work with different mechanisms. The following are the techniques used:

Pre-operative Femoral Nerve Block: Prior to the surgery, a catheter is placed beside the femoral nerve for blocking it. This nerve is located in the upper thigh. Medication is delivered through the catheter for the nerve to be numbed for 24 hours. Thus, pain signals to the brain are blocked. This method reduces the use of narcotics and the consequent side effects.

Patient Controlled Analgesia (PCA): This method is also known as  Pain Pump . An intravenous pump is used to administer pain relief medications, such as oxymorphone or morphine, after the surgery. The control button of the machine could be pressed, by the patient for 6 to 10 times per hour. The machine is used for two post-operative days.

Oral Medications: The oral medications include Non-Steroidal Anti-Inflammatory drugs or NSAID; such as Celebrex which is similar to aspirin, structurally. Alternatively, acetaminophen, such as Tylenol or its equivalent composition, can also be used.

Acetaminophen: It acts on the Central Prostaglandin Synthesis and relieves the patient of pain through multiple mechanisms.

Epidural Analgesia: It produces lower pain scores and involves less time for achieving physical therapy goals. However, this is subject to side effects such as dizziness, urinary retention and itchiness.

Gabapentinoids: These medications include membrane stabilizers such as Gabapentin and Pregabalin.

The objective of multimodal treatments is to provide quick relief to the patient and immediately so. Earlier the rehabilitation, more successful will be the knee replacement surgery.

Multimodal Pain Relief After Total Knee Replacement

Causes and symptoms of knee pain

Knee pain is characterized by a feeling of pain in the knee joint caused by injury or overuse. The knee joint consists of small bone structures, the kneecap, supporting ligaments and cartilage of the knee. This joint bears the full weight of the body, which makes it very vulnerable to injury.

Causes of knee pain

Knee pain is usually caused by injuries to the knee such as exposure to a direct force on the knee, abnormal twisting of the knee or falling on your knees. Some causes of knee pain are -

Knee strains and sprains - Overworking the knee joints can damage the tissues of the knee joint resulting in knee sprains and strains

Osteoarthritis - it is condition where the protective cartilage around the kneecap is damaged, resulting in knee pain

Bursitis - Excessive movement of the knee or kneeling down for extended periods can irritate the bursa (a fluid sac below the skin above the knee joint) that causes swelling and pain, thereby giving rise to this condition

Gout - This condition is characterized by the accumulation of uric acid in crystal form around the knee joint, causing inflammation and pain

Tendon disorders - Tendons connect the muscles to the bones, and overworking the knee can cause the tendons around the knee to become sore and painful

Kneecap dislocation - Injuries may cause the kneecap to shift out of its position, this causes swelling and pain in the knee joint

Symptoms of knee pain

Severe knee pain can restrict movements such as walking or standing. The symptoms vary according to the extent of the damage suffered by the knee. Most common symptoms of knee pain are problems in climbing stairs, inability to extend the knees, limping and swelling of the knee joint. In some cases, knee pain may also cause fever.

Causes and Symptoms of Knee Pain

Pain in the joints continues to bug mankind till this very day. There are different types of joint pains, which might occur all of a sudden, with no signs of receding. The most common of them all are arthritis, tennis elbow, frozen shoulder, back pain and repetitive muscular strain. These joint pains are sometimes impossible to diagnose properly by the regular modes of diagnosis. In those cases, resorting to the homeopathic mode of medication might be a good idea as it is a medication based on treating the actual cause of the disease and sustained use might result in complete remission of the pain.

Some commonly used homeopathic medications for pain in the joints are as follows:
1. Rhus Tox: This is the most commonly used in homeopathic preparation for severe joint pains, the symptoms of which include severe pain after relaxation, pain triggered by slightly wet weather and pain after walking or running for a long time.

2. Arnica Montana: When the symptoms are pain in every joint of the body resulting in body aches and pertaining injuries due to accidents, Arnica Montana serves as the perfect medication.

3. Actea Spicata: This medicine is primarily used as a remedy for pains in the small joints of the hands. The symptoms for which the medication can be implemented are rheumatoid arthritis in the joints of the finger and swollen wrists after usage of the hand.

4. Colchium: This medicine can be used in case of Rheumatoid Arthritis (inflammatory and chronic form of arthritis).

5. Bryonia Alba: This medication can work wonders if the symptoms include severe pain in the knee joints while walking, severe swollen joints and osteoarthritis (affects the flexible tissues present at the bone ends).

However, it is always advisable to take medication as prescribed by your doctor, as the potency and frequency can only be decided by your doctor.

Homeopathic Treatment for Pain in the Joints

Your knee is a very complex structure consisting of bones, ligaments, cartilage, tendons, muscles and meniscus. Most people encounter knee pain at some point in their lives. If your knee pain is chronic in nature, then it may last for a prolonged period.

Many causes may be responsible for your knee pain. Some of the causes are stated as follows:
1. Your knee is very much prone to injuries. Knee injuries may happen due to accidents, falling down carelessly or while playing sports. The most common knee injuries that may be the cause for your knee pain are mentioned as follows: 
a) Fractures may cause you to feel pain in the areas of your knee bones.
b) Anterior Cruciate Ligament injury (ligament injury caused by twisting and a sudden motion) or Medial Collateral Ligament injury (injury to the tissue in the insides of your knee) is very common to sportspersons and may be the reason for severe knee pain.
c) Sometimes your knee bones may get dislocated from their usual alignment. This can also make you experience severe knee pain.
d) Ligament injuries, meniscus tear or tendon tear can also be responsible for your knee pain.

2. Sometimes pain in your buttock or foot region can also result in mild knee pain.

3. At times chronic problems like osteoarthritis that affects the cartilage can cause the problem of knee pain. Other chronic problems like Gout, rheumatoid arthritis can also cause severe knee pain.

4. Being overweight can also result in knee pain.
The symptoms of knee pain may be different in each case. The most common symptoms are mentioned below:
a) Stiffness of knee
b) Swelling of your knee
c) You may also feel unstable
d) Difficulty in walking or bending of your knee.
e) You may notice redness in your knee area.

Knee pain must not be ignored. It is highly recommended for you to seek advice from an orthopedic as soon as you encounter any of the above mentioned symptoms.

Suffering from Knee Pain - Know What Causes it? 

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