Take care of your knees, knee osteoarthritis is more than just wear and tear!

This is the 4201st article of Da Yi Xiao Hu

Aunt Huang is 69 years old. She has had recurrent left knee pain for the past six months, especially when going up and down stairs and sitting or standing for long periods of time. She was very distressed about this, so her family took her to the hospital for treatment. The doctor diagnosed "left knee osteoarthritis" based on symptoms, signs and imaging examinations. Considering that the injury site was on the medial articular surface of the left knee and the cartilage of the lateral compartment of the left knee was good, the doctor performed a minimally invasive left knee unicompartmental replacement on Aunt Huang. A few days after the operation, she was able to walk in the ward, and Aunt Huang showed a relaxed smile. Osteoarthritis is a chronic disease that people often encounter in life, and it can seriously affect daily life. Today, let's talk about knee osteoarthritis!

What is knee osteoarthritis?

Before we get into the topic, let's first understand an important structure of the knee joint - knee cartilage. In order to avoid direct contact between two hard bones, relieve joint pressure and reduce wear, there is a thin layer of cartilage on the contact surface of the femur and tibia in the knee joint, and the gap between the two is filled with two crescent-shaped fibrous cartilages, namely menisci, which further enhance the protection of the knee joint.

The source of knee osteoarthritis is the lesions of these cartilages. It is a chronic joint disease characterized by degenerative lesions of knee cartilage, narrowing of joint space and secondary osteophytes. Based on the pathological characteristics of osteophyte hyperplasia, it is more commonly known as "bone hyperplasia" in clinic and among the public. The following X-ray of Aunt Huang before surgery shows very typical manifestations of osteoarthritis.

Preoperative X-ray of Aunt Huang

(The red arrow indicates the narrowing of the joint space, and the black arrow indicates bone hyperplasia)

Knee osteoarthritis is one of the most common joint diseases, affecting more women than men. The incidence rate increases rapidly with age due to joint aging. More than half of the population over 65 years old is affected by it, and the disability rate is high.

What are the symptoms of knee osteoarthritis?

1. Joint pain

The first thing most people feel is joint pain. In the early stage, the pain is mild to moderate and can be relieved by rest. The pain can be induced or aggravated by cold. As the disease progresses, the pain may first affect going up and down stairs or squatting and standing up. If it continues to develop, it will further affect walking on flat ground. In the late stage, persistent pain may occur and significantly affect activities, even affecting sleep and non-weight-bearing activities.

2. Limited joint movement

When you get up in the morning, your joints become stiff and your range of motion decreases, which is called "morning stiffness". It usually lasts for 30 minutes and can be relieved by moving around. In the late stage, joint movement can be significantly limited, and even lead to disability.

3. Joint deformity

The deformity is not obvious in the early stage, but as the disease progresses, obvious varus, valgus, and rotation deformities may appear. Genu varum deformity ("O"-shaped legs, bow legs, and bow legs) is the most common. Many patients will deny that they have "O"-shaped legs, saying that they did not have them when they were young, but as a doctor, you should correctly inform the patient that the appearance of knee varus deformity at this time is a degenerative disease.

4. Joint swelling

Some knee joints may experience joint swelling due to bone hyperplasia or joint effusion. The most likely areas to experience visible swelling include the suprapatellar bursa, which is the structure above the patella of the knee joint, and the knee pit.

5. Bone friction (sound)

When the articular cartilage is destroyed and the joint surface is uneven, a feeling of friction or creaking may occur during joint movement.

How to treat knee osteoarthritis?

A pyramid-style step-by-step treatment is often used for knee osteoarthritis, including basic treatment, drug treatment, and surgical treatment (reparative and reconstructive).

Step therapy diagram

(Wang Bo, Yu Nansheng. Expert consensus on step-by-step treatment of knee osteoarthritis (2018 edition)[J]. Chinese Journal of Joint Surgery (Electronic Edition), 2019, 13(01): 124-130.)

1. Basic treatment

For people with mild lesions and symptoms, basic treatment is usually the main treatment, combined with daily health care, changing bad living habits and work habits in daily life. Long-term bad postures, such as jumping, squatting, running, etc., should be avoided, and climbing mountains and stairs should be avoided. Obese people should lose weight appropriately.

With appropriate exercise, do some low-intensity aerobic exercise such as jogging, brisk walking, cycling, swimming, etc. under the guidance of a doctor. Strengthen the strength training of muscles around joints. You can use equipment or freehand training to carry out isokinetic, isometric, and isotonic exercises. Train joint function, perform flexion and extension activities in a non-weight-bearing position, maximize joint mobility, and improve training effects through passive stretching. You can also use some mobility aids, such as walkers, canes, joint braces, etc. In addition, physical therapy such as heat therapy, cold therapy, hydrotherapy, massage, etc. can also be used to improve local blood circulation.

2. Drug treatment

Appropriate drug treatment can be carried out under the guidance of a doctor. Commonly used drugs include non-steroidal anti-inflammatory drugs and drugs that protect articular cartilage (such as glucosamine). When oral topical medications are not effective, doctors often choose joint cavity drug injection treatment. Commonly used drugs include glucocorticoids and sodium hyaluronate.

Glucocorticoids are usually mixed with local anesthetics such as lidocaine and injected into the painful area. This is the blockade therapy we often hear about. Many patients are afraid of blockade and think that it is a harmful treatment. In fact, this is a misunderstanding. For persistent pain and obvious inflammation, especially when 4 to 6 weeks of oral medication is ineffective, the guidelines recommend the use of blockade therapy. However, it is also necessary to recognize that long-term hormone treatment may aggravate articular cartilage damage and worsen symptoms. Therefore, generally no more than 3 to 4 injections per year! Sodium hyaluronate is similar to artificial joint fluid, which can improve the internal environment of the joint cavity by increasing the viscosity and elasticity of the joint surface, relieving inflammation in the joint cavity, and activating the production of endogenous hyaluronic acid.

3. Surgical treatment

If conservative treatment is ineffective after 3 months, symptoms continue to worsen, and seriously affect daily walking, surgical treatment is required. Surgery can be divided into two categories: restorative (arthroscopic cleaning, osteotomy, etc.) and reconstructive (joint replacement). The specific indications of each procedure are also different. Patients should discuss with their attending physicians based on their own conditions and choose the appropriate surgical plan.

Keeping the "knee" in mind - Unicompartmental knee replacement

The unicompartmental knee replacement that Aunt Huang underwent only involves surface replacement of the medial or lateral chamber of the knee joint. The main purpose is to use an artificial prosthesis to replace the damaged part, retaining the normal structure of the opposite side. This can achieve the treatment effect without having to replace the entire joint. It is similar to what we often call tooth replacement. The part with the problem is replaced, and the treatment is more precise.

Schematic diagram of unicompartmental surgery

X-ray of Aunt Huang after surgery

(The red arrow is the prosthesis, and the black arrow is the joint space)

Although unicompartmental knee replacement is currently widely used in clinical practice, it has the advantages of short operation time, less trauma, less postoperative pain, quick recovery, good postoperative function, and low infection rate. However, it should be noted that unicompartmental knee replacement also has strict indications. It requires that the lesion is concentrated in the unilateral "compartment", the ligaments in the knee joint are intact, and there are certain requirements for the range of motion of the joint. Do not blindly "follow the crowd" because of the efficacy of others.

Author: Yueyang Hospital of Integrated Traditional Chinese and Western Medicine affiliated to Shanghai University of Traditional Chinese Medicine

Zhu Bo and Feng Shengyi from Orthopedic Center