Knee Osteoarthritis

Last updated date: 18-Jul-2022

Gleneagles Hospital Penang

13 mins read

Overview

Knee Osteoarthritis

Knee osteoarthritis (OA), commonly known as degenerative joint disease of the knee, is caused by wear and strain and gradual articular cartilage loss. It affects the elderly the most. Primary and secondary osteoarthritis of the knee can be distinguished. Primary osteoarthritis is articular deterioration that has no obvious cause. Secondary osteoarthritis develops as a result of an aberrant distribution of force across the joint, such as after a severe injury, or abnormal articular cartilage, such as in rheumatoid arthritis (RA).

Osteoarthritis is a condition that usually worsens with time and can lead to impairment. The severity of clinical symptoms varies from person to person. Over time, however, they usually grow more severe, more frequent, and debilitating. Each person's rate of advancement is likewise different.

Knee pain that develops gradually and increases with movement, knee stiffness and swelling, discomfort after extended sitting or sleeping, and pain that worsens with time are all common clinical signs. When conservative treatment approaches for knee osteoarthritis fail, surgical therapy alternatives are considered. 

 

What is Knee Osteoarthritis? 

Osteoarthritis

Osteoarthritis is a condition of the knee characterized by wear or degeneration of the knee cartilage due to repeated stress on the cartilage.

A more detailed description of osteoarthritis and an interview with a leading orthopedist from South Korea:

Knee Arthrosis Facts - Viewpoints from Expert Doctors

 

Anatomy

knee anatomy

The knee is the largest and strongest joint in your body. It is made up of the lower end of the femur (thighbone), the upper end of the tibia (shinbone), and the patella (kneecap). The ends of the three bones that form the knee joint are covered with articular cartilage, a smooth, slippery substance that protects and cushions the bones as you bend and straighten your knee.

Two wedge-shaped pieces of cartilage called meniscus act as "shock absorbers" between your thighbone and shinbone. They are tough and rubbery to help cushion the joint and keep it stable.

The knee joint is surrounded by a thin lining called the synovial membrane. This membrane releases a fluid that lubricates the cartilage and reduces friction.

 

Epidemiology

The most prevalent kind of arthritis identified is knee osteoarthritis, and its prevalence will continue to climb as life expectancy and obesity increases. According to various sources, symptomatic knee osteoarthritis affects around 13% of women and 10% of men aged 60 and over. The frequency increases to as high as 40% among persons over the age of 70.

Males have a lower frequency of knee osteoarthritis than females. Surprisingly, not everyone with radiographic evidence of knee osteoarthritis will have symptoms. Only 15% of individuals with radiographic evidence of knee OA were symptomatic, according to one research. Without taking into account age, the annual incidence of symptomatic knee osteoarthritis is around 240 cases per 100,000 individuals.

 

Knee osteoarthritis causes

Knee osteoarthritis causes

Depending on the etiology, knee osteoarthritis is classed as either primary or secondary. Primary knee osteoarthritis occurs when articular cartilage degrades for no apparent cause. This is commonly thought of as age-related deterioration as well as wear and tear. The outcome of articular cartilage deterioration owing to a recognized cause is secondary knee osteoarthritis.

Possible Causes of Secondary Knee OA

  • Posttraumatic
  • Postsurgical
  • Scoliosis
  • Rickets
  • Hemochromatosis
  • Gout
  • Pseudogout
  • Acromegaly
  • Rheumatoid arthritis
  • Infectious arthritis
  • Psoriatic arthritis

 

Risk Factors for Knee OA

Modifiable

  • Articular trauma
  • Occupation – prolonged standing and repetitive knee bending
  • Muscle weakness or imbalance
  • Weight
  • Health – metabolic syndrome

Non-modifiable

  • Gender - females more common than males
  • Age
  • Genetics
  • Race

 

Pathophysiology

knee osteoarthritis

Type II collagen, proteoglycans, chondrocytes, and water make up the majority of articular cartilage. Healthy articular cartilage maintains a steady balance between each of the components, ensuring that any cartilage deterioration is countered by synthesis. As a result, healthy articular cartilage is preserved. Matrix metalloproteases (MMPs), or degradative enzymes, are overexpressed in osteoarthritis, upsetting the balance and resulting in a loss of collagen and proteoglycans.

In the early phases of osteoarthritis, chondrocytes release tissue inhibitors of MMPs (TIMPs) in an attempt to match the degradative process with increased proteoglycan production. This healing process, however, is insufficient. The breakdown of balance causes a drop in the number of proteoglycans despite increasing synthesis, an increase in water content, a disordered collagen pattern, and finally articular cartilage elasticity loss. On a macroscopic level, these alterations result in cartilage cracking and fissuring, as well as articular surface degradation.

Although knee osteoarthritis is strongly linked to age, it is crucial to remember that it is a separate illness from aging. The changes in cartilage noticed with osteoarthritis and aging support this theory. Furthermore, the enzymes that cause cartilage breakdown are overexpressed in knee osteoarthritis, whereas they are underexpressed in normal aging cartilage.

 

What are the symptoms of osteoarthritis?

symptoms of osteoarthritis

Knee discomfort is the most common problem that patients bring to their doctor. As a result, obtaining a full history of their symptoms is critical. Knee pain might be referred from the lumbar spine or the hip joint, so pay attention to the history. It's also crucial to have a thorough medical and surgical history to see whether there are any risk factors for secondary knee OA.

The history of the present illness should include the following: 

  • Onset of symptoms
  • Specific location of pain
  • Duration of pain and symptoms
  • Characteristics of the pain
  • Alleviating and aggravating factors
  • Any radiation of pain
  • Specific timing of symptoms
  • Severity of symptoms
  • The patient's functional activity

 

Clinical Symptoms of Knee OA

Knee Pain

  • Gradual onset
  • Worse with prolonged activity
  • Worse with repetitive bending or stairs
  • Worse with inactivity
  • Worsening over time
  • Better with rest
  • Better with ice or anti-inflammatory medication
  • Knee stiffness
  • Knee swelling
  • Decreased ambulatory capacity

A visual assessment of the knee should be the first step in the physical evaluation. Look for periarticular erythema and edema, quadriceps muscle atrophy, and varus or valgus deformities while the patient is standing. Examine your walk for indicators of knee joint discomfort or irregular motion, which might suggest ligamentous instability. Next, check the surrounding skin for any scars from past surgical operations, underlying indications of trauma, or soft tissue lesions, and note their position.

The range of motion (ROM) test is an important part of the knee examination. Active and passive flexion and extension ranges of motion should be measured and recorded. Any knee exam should include palpation of the bone and soft tissue structures. The medial, midline, and lateral structures of the knee can be examined using a palpatory exam.

A comprehensive neurovascular examination should be carried out and documented. It is critical to check the quadriceps and hamstring muscles' strength, as these muscles frequently atrophies in the presence of knee discomfort. A sensory examination of the femoral, peroneal, and tibial nerves should be performed to rule out any related neurogenic complaints. Any anomalies in the popliteal, dorsalis pedis, or posterior tibial pulses should raise concerns about vascular issues.

 

Knee Osteoarthritis Diagnosis 

Knee Osteoarthritis Diagnosis

Radiographic imaging is necessary in addition to a complete history and physical examination. Standing anteroposterior (AP), standing lateral in extension, and a skyline view of the patella are all recommended views. A standing 45-degree posteroanterior (PA) image of the knee may be acquired, which allows for a more accurate assessment of the knee's weight-bearing surface.

Long leg standing films are occasionally taken to evaluate the degree of deformity and general alignment of the lower extremity. It's crucial to remember that radiographs of the knee must be taken when the patient is standing. This accurately depicts the joint space narrowing that is present. Films are frequently obtained with the patient lying down, which gives a misleading perception of joint space and alignment and should not be utilized to assess suspected knee OA.

 

Radiographic Findings of OA

  • Joint space narrowing
  • Osteophyte formation
  • Subchondral sclerosis
  • Subchondral cysts

 

What is the treatment for osteoarthritis?

treatment for osteoarthritis

Non-surgical and surgical treatment options for knee osteoarthritis are available. Therapy begins with non-surgical techniques and progresses to surgical treatment once non-surgical procedures have failed. For the treatment of knee osteoarthritis, a variety of non-surgical options are available. These treatments do not change the underlying illness process, but they can reduce pain and impairment significantly.

 

Non-Surgical Treatment Options 

  • Patient education
  • Activity modification
  • Physical therapy
  • Weight loss
  • Knee bracing
  • Acetaminophen
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • COX-2 inhibitors
  • Glucosamine and chondroitin sulfate
  • Corticosteroid injections

 

Patient education and physical therapy are the first-line treatments for all individuals with symptomatic knee osteoarthritis. The highest outcomes have been seen when supervised activities are combined with a home exercise regimen. If the workouts are abandoned after 6 months, the advantages are gone.

Unloader-type braces that move the weight away from the affected knee compartment are used in arthritic knee bracing. This might be beneficial in situations when the lateral or medial compartments of the knee are implicated, such as a valgus or varus deformity.

For individuals with symptomatic osteoarthritis, drug therapy is also the first-line treatment. There are many different NSAIDs to choose from, and the decision should be made based on medical preference, patient acceptance, and cost. The duration of NSAID medication should be determined by the efficacy, side effects, and previous medical history.

Dietary supplements such as glucosamine and chondroitin sulfate are available. They are structural components of articular cartilage, and it is assumed that taking a supplement can help articular cartilage stay healthy. According to the AAOS recommendations, there is no good evidence that these supplements are effective in knee OA; in fact, there is significant evidence against their usage. Taking the supplement has no significant drawbacks. It is a pretty safe alternative if the patient knows the research behind these supplements and is prepared to take them. Supplemental benefits are almost certainly attributable to the placebo effect.

Intra-articular corticosteroid injections can help with symptomatic knee osteoarthritis, especially if there is a lot of inflammation. The administration of a corticosteroid directly into the knee may lessen local inflammation associated with osteoarthritis while also reducing the steroid's systemic effects.

Another injectable option for knee osteoarthritis is intra-articular hyaluronic acid injections (HA). HA is a glycosaminoglycan that can be found all over the human body and is found in synovial fluid and articular cartilage. HA degrades with the progression of osteoarthritis, contributing to articular cartilage degradation, stiffness, and pain.

Local HA distribution into the joint functions as a lubricant and may aid in increasing the joint's natural HA production. HA can be made in the lab from avian cells or bacterial cells, depending on the brand, and should be taken with caution in people who have avian allergies.

Depending on the extent of the knee condition, some mild or early osteoarthritis can be treated with non-surgical treatments such as radiofrequency ablation (RFA), platelet-rich plasma (PRP), hyaluronic acid injections. Nick (HA) and stem cells.

Radiofrequency stops the nerve that brings pain to the knee by coagulating it, especially at three specific points of the knee. The advantage of this procedure is that the patient can stay awake during the procedure and the procedure only takes about 20 minutes. It is a cheaper option compared to surgery and the patient can walk immediately after. Radiofrequency of the knee can be performed as a day care procedure.

Mild cases of knee pain can be treated with glucosamine alone or in combination with chondroitin. Doctors also recommend injecting hyaluronic acid into the knee. Hyaluronic acid injections help mild to moderate osteoarthritis by lubricating as well as relieving knee pain. These injections generally provide relief for approximately 6 months to 1 year.

Platelet-rich plasma (PRP) injection is a procedure in which we extract the patient's own blood, which is centrifuged, receive a small amount of pure PRP and inject it into the knee. The advantage of this procedure is that it does not require surgery, is cheaper than surgery and can be performed in an outpatient clinic.

Through the above treatment options, we aim to provide pain-free knees for our patients, as well as delay the need for knee replacement and the progression of osteoarthritis.

 

Severe osteoarthritis

If all of the above treatments don't work, or if the disease is too severe, the only option is surgery. Total knee replacement surgery is the best option for these patients. For patients 65 years and older with severe osteoarthritis, total knee replacement surgery offers the best solution to relieve pain and improve patient function and quality of life.

 

Surgical Treatment for knee osteoarthritis

Surgical Treatment osteoarthritis

Surgical options include:

  • Osteotomy
  • Unicompartmental knee arthroplasty (UKA)
  • Total knee arthroplasty (TKA)

Noncompartmental knee osteoarthritis accompanied with malalignment may need a high tibial osteotomy (HTO). An HTO is commonly used to treat varus deformities in which the medial compartment of the knee has become worn and arthritic. A youthful, active patient who would fail arthroplasty owing to excessive component wear would be a great candidate for an HTO.

The real knee joint, including the cruciate ligaments, is preserved with an HTO, and the patient can return to high-impact activities once recovered. It takes longer to heal than an arthroplasty, is more prone to problems, is dependent on bone and fracture healing, is less effective at relieving pain, and does not replace or repair any cartilage that has already been lost. An osteotomy can postpone arthroplasty for up to ten years.

 

Knee replacement surgery 

Knee replacement surgery is very successful with minimal risks. Knee replacements can last 15 to 20 years and more if the operation is done properly. Perfect accuracy in all knee replacement surgeries can be achieved continuously using Computer Aided Surgery (CAS). CAS is the latest technology in knee replacement surgery that produces more accurate results compared to other knee replacement surgeries. with general knee replacement surgery

Knee replacement surgery is the best surgery for severe osteoarthritis of the knee. However, this should only be done after trying all other treatment options. It should be reserved as a salvage procedure when all other treatment options have failed. The disadvantages of knee replacement surgery include:

  • It is an important operation that requires a long recovery time.
  • Dental implants have a lifespan of only 15-20 years.
  • Restriction of activities after surgery, such as inability to kneel, crouch, sit cross-legged

Newer surgical options, such as the nearby fibula osteomy (PFO), are gaining in popularity. In this procedure, a small portion of the fibula bone of the leg is removed and this restores the natural mechanical axis of the affected knee. Removal of a small portion of the fibula bone does not cause any functional limitations in the knee or leg. The advantages of PFO are:

  • Short surgery duration (15-20 minutes)
  • good value
  • Can walk the same day or the next day.
  • There are no metal implants in the body.

 

Recovery

Physical therapy

There is a healing period after any sort of knee surgery for arthritis. The length of recovery and rehabilitation is determined on the type of surgery performed.

Physical therapy may be recommended by your doctor to help you regain knee strength and range of motion. Depending on your operation, you may need to use crutches or a cane for a period of time. Surgery, in most situations, improves discomfort and makes it easier to do everyday tasks.

 

Can osteoarthritis be avoided?

Prevent knee injuries

The breakdown and wear and tear of cartilage is inevitable as we age. However, we can take some steps to reduce knee pain and to prevent the stiffness caused by osteoarthritis.

  • Body weight control

Being obese or overweight makes wearing cartilage worse due to the extra strain on the cartilage. Losing weight will slow down the mobility of osteoarthritis.

  • Exercise regularly

Exercising our joints, especially our knees, helps to strengthen the muscles around the joints. The strong muscles as a result of regular exercise protect our knees and absorb part of the stress exerted on them. Exercise also helps prevent stiffness in the joints. Exercises that are beneficial for the knee include cycling and swimming.

  • Prevent knee injuries

Knee injuries put cartilage at a higher risk for osteoarthritis. Therefore, adequate warm-up before exercise and wearing protective gear such as knee guards help prevent knee injuries. If you have developed any sports injuries, the knee is treated early by an orthopedic surgeon.

We should take these precautions while our knees remain healthy. However, even if we develop mild or early osteoarthritis, we can still practice these measures to maintain good knee function and to prevent osteoarthritis from getting worse.

 

Conclusion

Knee osteoarthritis is a prevalent debilitating ailment that affects one-third of people over the age of 65. Exercise, weight loss, physical therapy, intra-articular corticosteroid injections, nonsteroidal anti-inflammatory medications, and the use of braces or heel wedges can all help to relieve discomfort and improve function. Acetaminophen, glucosamine, ginger, capsaicin cream, topical nonsteroidal anti-inflammatory medications, acupuncture, and tai chi are some of the treatments that may help. Tramadol has a poor risk-benefit ratio and is thus not commonly prescribed.

Individuals with moderate to severe pain or a reduced quality of life are increasingly using opioids, but because of the medications' intrinsic side effects, these patients must be carefully selected and managed. Injections of intra-articular corticosteroids are useful, however the evidence for hyaluronic acid injections is inconsistent. In the case of knee osteoarthritis, arthroscopic surgery has been demonstrated to be ineffective. When conservative symptomatic therapy fails, total joint replacement of the knee should be explored. 

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