Joint Center

Damage on the knee joint

01 Outlines

Structure of a knee joint

As the biggest joint in a human’s body, the knee joint’s bone structure is formed with thigh bone, shin bone, and the patella. This bone structure is surrounded with various ligaments such as medial & lateral collateral ligament(knee), anterior & posterior cruciate ligament, and medial & lateral meniscal, with other soft tissues like muscle and tendon.

Damage on the knee joint

Since the knee joint has a unstable structure compared to other joints and located in a vulnerable point at our body, it is easily damaged by external shock. So the various soft tissues in and out of the joint places a huge role in the joint’s safety and protection.

Therefore when symptoms like pain and edema occurs, it is of course important to confirm the existence of bone damage like perigenual fracture. But it is also important to detect damage on the lateral meniscal, cruciate ligaments, collateral ligament(knee), cartilage, surrounding muscles and tendons, which plays a huge role as much as the bone structure. If a patient has a fracture around the knee joint doesn’t mean that it is the only injured part. We should not only think about the fracture, but also not overlook the damage on the particular soft tissues.

Knee joint examination

During the procedure of examining the knee joint injury, the damage on the bones are somewhat able to diagnose with simple radiographic inspection. However the damage on the cartilaginous plate and ligaments are not easy to diagnose with simple radiographic inspection. So a thorough medical examination using the MRI(magnetic resonance imaging) is needed. It is important to receive medical treatment from a experienced doctor when you have a injured knee joint, but it is also important for the patient oneself to know the injury’s medical history, symptoms, current conditions, progress and inform to the doctor about it.

Now we will learn about some of the major injuries that can occur to the knee joint such as semilunar cartilage injury, cruciate and collateral ligament(knee) injury, cartilage injury, intra-articular fractures.

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02 Ligament Injuries


Yes there are various ligaments in the knee joint, but the most important 4 ligaments will be anterior cruciate ligament, rear cruciate ligament, medial collateral ligament(knee) and lateral collateral ligament(knee). Since these ligaments play a key role in the stability of the knee joint, when damaged you may experience instability in the anterior and posterior, flank, and rotation. At the acute phase which is referred as the situation right after the damage, many patients cannot receive accurate diagnosis because of pain, edema, tension and cramp on the muscle. So a constant examination of the physical and symptom change should be proceeded with giving some time.

Anterior cruciate ligament injury

- Symptoms

The anterior cruciate ligament is the most commonly injured ligament within the knee joint. Suppose that a man and woman exercise the same amount and degree, the risk of anterior cruciate ligament damage are about 4~8 times higher for woman. Many patients experience anterior cruciate ligament damage during exercise such as soccer, skiing, contact or non-contact damage by excessively moving the knee joint. Patients tend to feel a smacking sound on the knee, and experience severe pain, edema on the joints after the injury.

- Diagnosis

First we confirm the instability of the anterior, posterior or rotation, then proceed additional examinations such as stress radiograph, MRI(magnetic resonance imaging), arthrometer test for accurate diagnosis. When in a chronic condition, you may experience constant instability, the ineffectualness in the knee joint, repeated relapse of the edema, etc. The patient complains difficulties when walking uneven ground, stairs, slopes or when changing directions. As the muscular strength at the muscle quadriceps femoris which is surrounding the knee joints, gradually weakens muscle dystrophy proceeds.

- Treatment

For the treatment of anterior cruciate ligament, it differs depending on the degree and location of the damage, degree of the instability, patient’s age, patient’s livelihood, patient’s physical activity degree, but in general many proceed surgical treatment. Since the anterior cruciate ligament lacks of self-healing powers than the collateral ligament(knee), it rarely recovers functioning by non-surgical conservative therapy. Except some patients with old age, a certain degree of osteoarthritic changes progressed, low physical activity degree, partial rupture patients that has no symptoms, we usually proceed into surgical treatment.

A method that sutures the ruptured ligaments are currently not used well, we usually proceed arthroscopic ACL(anterior cruciate ligament) reconstruction with auto or homo transplantation. We reconstruct the ligament into one or two strands and also reconstruct by using the computer assisted navigation device too.

- Complications

Complications that may occur after operation are pain on the patello femoral joint, patellar fracture, joint fibroma, exercise limitation.

- Rehabilitation after surgery

Rehabilitation after anterior cruciate ligament surgery is crucial. With the adequate period of protection and timely exercise, a use of knee brace is generally needed. You must avoid hyper-extension on the knees, and try not to get bending build-up which is a disease that cannot fully stretch the knee joints. Do not make a sudden stretch on the flexion angle, stretch the knee brace’s angles stages by stages. This is also applied in weight bearing too, we first proceed partial weight bearing and when the surgery is over then we fully proceed weight bearing. Exercising for strengthening of the muscles are very important, but since the early time after the surgery the solidity of ligaments are weak, no excessive load should be bore on the knees.

Posterior cruciate ligament injury

- Symptoms

Posterior cruciate ligament injury are commonly occurred by the immediate impact on the shin bone’s upper unit while the knee joint is curved. It may occur in many cases such as: by a car crash, especially a motorcycle accident or injury on the dashboard, an athlete falling while curving the planta pedis on the foot. When you experience hyper-extension damage on the knee joint, injury could happen with not only the posterior cruciate ligament but also the other ligaments.

Like anterior cruciate ligament injury, patients also experience pain and edema after the injury. However since the symptoms of hemarthrosis and instability tend to rarely occur than the ACL(anterior cruciate ligament) injury, not many posterior cruciate ligament injuries are diagnosed at acute phase and overlooked. So the condition of the external wound should be confirmed through detailed medical history hearing.

Posterior cruciate ligament injury has very low repetition rates than anterior cruciate ligament injury. This ligament prevents the shin bone, which is located at the lower bone of the knee joint, transpose backwards and is also the central axis in the knee joint’s rotation. The injury can be diagnosed through the pain in acute phase, instability symptoms in the chronic phase, examining about the instability, stress radiograph, MRI(magnetic resonance imaging). As many patients experience multiple ligament damage rather than isolated ligament damage, about 60% of injuries are accompanied by posterior ligament complex and other ligament damages. So it is crucial to check the existence of accompanied damage on other ligaments.

- Treatment

Compared to ACL(anterior cruciate ligament), PCL(posterior cruciate ligament) injury treatment has many non-surgical treatable cases. With the case of low instability and partial or isolated injury, we usually treat with non-surgical treatments. We protect the injured ligaments by fixating the knee and forbidding weight bearing. After certain time, a gradual exercise and weight bearing is proceeded.

As for avulsion fracture that has damaged with fractured pieces, if not treated with conservative therapy we perform a fixation surgery using the screw nail. And for the damage in the ligament itself, we perform a reconstruction with auto or homo transplantation. The result of these reconstruction’s subjective satisfaction levels are quite high, but in the respect of objective safety it is lower than ligament reconstruction surgery.

Collateral ligament(knee) injury

- Symptoms

Medial collateral ligament(knee) injuries are usually occurred by the valgus force which makes the legs bend outwards, and in the contrary, lateral collateral ligament(knee) is usually damaged by varus force that bends the legs inwards. At acute phase, there may be symptoms and physical examination opinions such as : pain, edema, an oppressive pain in the interval space of the joints, increase of interval space of the joints. In chronic phase, the patient may subjectively feel the instability in the joints and show instability at physical examinations.

- Examination

In collateral ligament(knee) examinations, MRI(magnetic resonance imaging) and stress radiograph which tests by giving varus or valgus force on the knee, are very effective.

- Treatment

When treating medial collateral ligament(knee) injuries, not many patients go through surgery. They are usually treated with conservative therapy like drug treatment, banning weight bearing, knee braces, rehabilitation therapy. Same for lateral collateral ligament(knee) injuries, it may differ depending on the degree of accompanied damage but many are treated with conservative therapy. In case of collateral ligament(knee) surgery, there are two types. One is a surgery that conserves or strengthens the ligament itself, and the other is the one that performs reconstruction with auto or homo transplantation.

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03 Cartilage injury


Patients visit us when they experience : when the cartilage in the joint peels off because go external injury, subchondral separation, depending on the degree it may occur loose body(joint mice). Usually after external wound a necrosis impression called desquamative osteochondritis, a disease that is caused because of the pieces of the ligament and subchondral coming off from the articular surface, is occurred. This is the most common cause of the loose body(joint mice) in company with the osteochondral fracture.

How to cure desquamative osteochondritis

Except patients with active growth plate that has stable lesion without experiencing complete peeling on the joints, many desquamative osteochondritis patients go under a surgical treatment. But for adult patients with symptoms, even if it’s a stable lesion since it has little chance of self-healing, a surgery is necessary.

As for surgical treatment of desquamative osteochondritis, it is determined depending on the degree of necrosis, malt modification of the bone splinters and lesional locations. We can fixate the fractured pieces using headless screw nails, with simultaneous or isolated perform of cartilage tissue regeneration surgery. There are various types of cartilage tissue regeneration : Micro-fracture that stimulates the bone marrow, auto or homo osteochondral transplantation, auto cartilage cell transplantation. Patients get to choose the adequate treatment that fits the health condition from these various treatments.

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04 Periarticular knee joint fracture

Periarticular knee joint intra-articular fracture

There are 3 big types in periarticular knee joint fracture: distal femur fracture, patellar fracture, tibial fracture. If you’re experiencing an invasion on the articular surface during these fractures, as it is a periarticular knee joint fracture, it is needed of even more aggressive treatment than those who aren’t. Although it is desirable to proceed early range of knee joint exercise after stabilized surgical fixation, it is also important to consider the conditions of the soft tissue and appropriate protection period. With plain radiograph and CT(Computed tomography) it is easy to identify the location and degree of the fracture. And when necessary, it is able to confirm the degree of accompanied damage using the MRI(Magnetic resonance imaging). For now, we will only inform you about the intra-articular fractures.

Intra-articular fracture of the distal femoral

A conservative treatment like casting knee braces may proceed after performing skeletal traction, but many patients are needed of surgical treatment.

Intra-articular fracture of the articularis patellae

If the stratiform on the articular surfaces are over 2mm, or the transposition of the fractured pieces are over 3mm a surgical treatment is necessary. For the case of conservation treatment are available, we first proceed cylindrical casting or long leg casting then wear a hinge knee brace, wearing a knee brace from the first step is also an option. When proceeding a surgical treatment, we fixate it by isolation or combination of the screw nail and steel wire. In case of severe rupture, we may perform removal of the fractured pieces.

Intra-articular fracture of the proximal tibia joint

It is usually caused by axial direction and load on the flank or when these two happen at the same time, making the thigh bone bump into the shin bone resulting the fracture on the tibial plateau(proximal joint region). Compared to medial tibia fracture, many of the patients visit the hospital because of lateral tibia fracture. Since the elderly patients have fragile bones, a depressed fracture is easily occurred. Besides the fracture, we must be careful of accompanied damage in the soft tissues such as ligaments, cartilaginous plate, nerves, blood vessels.

We usually recommend surgical treatments, but if there are no or least transposition there, we also proceed conservative therapy using the knee braces. When going through surgical treatment, isolated fixation with the screw nail, fixation using the metal plate and screw nail, external fixation is proceeded in a isolated or combined way. And if necessary, the help of arthroscope is available.

As for indications that can occur after surgery are infection, ankylosis, traumatic joint inflammation, mal-alignment, failure or non-union of the fixation, thromboembolism.

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05 FAQ

Q. I was while hurt playing soccer, and been diagnosed lateral meniscal tear after MRI scans. Is surgery mandatory when lateral meniscal is torn?

Not every lateral meniscal tear needs surgical treatment. If the fractured pieces that were caused by meniscal tear, move to the gap of the thigh bone and shin bone while knee joint movement, this may occur mechanical symptoms such as stiffness, slaphappiness, locking, pain on the articular surface, edema which needs surgical treatment. But if you’re rupture size is smaller than longitudinally 1cm, since it usually maintains stability, it does not need surgical treatment.

Q. When is the best timing for an anterior cruciate ligament injury operation?

As for acute reconstruction surgery on the ACL(anterior cruciate ligament) rupture, if you have no knee joint edema, inflammation diagnosis and are capable of bending the knee joint at least 125 degrees, the surgery is okay to proceed no matter the injured period. In general, many patients proceed the surgery 2 weeks after the injury.

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Medical Team

  • 이호민

    medical director

    Lee Homin


    Frozen shoulder, shoulder joint, arthroscope, knee/shoulder joint, high level difficulty trauma surgery, arthroplsty, ankle joint, rotator cuff tear, trauma clinic, pain clinic etc.

  • 서우석

    Vice president of the department of Orthopedics

    Seo Useok


    External wound(fracture, sprain), orthopedics diseases such as knee joints, trauma clinic, pain clinic, frozen shoulder, cruciate ligament damage etc.

  • 황순호

    Vice president of the department of Orthopedics

    Hwang Soonho


    Frozen shoulder, shoulder joint, arthroscope, knee/shoulder joint, high level difficulty trauma surgery, arthroplsty