Arthrofibrosis: Causes, Symptoms, and Treatment

Arthrofibrosis is a dreaded, in its etiology largely unexplained joint disease following surgery or injury, resulting in a more or less severe, sometimes painful restriction of joint mobility.

A distinction is made between the following:

  • Primary arthrofibrosis, which is characterized by generalized scarring in the joint.
  • Secondary arthrofibrosis, in which local mechanical irritations are the cause of a restriction of movement.

Most studies in the literature have dealt with the development of arthrofibrosis of the knee joint after injuries and cruciate ligament plastic surgery.

From a clinical point of view, arthrofibrosis of the knee joint is defined by a permanent restriction of movement of > 10° for extension and <125° for flexion.

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Symptoms of arthrofibrosis

A characteristic feature of arthrofibrosis is the restriction of movement of the affected joint.

If a local mechanical problem is the cause of the movement restriction, symptoms sometimes occur as pinching symptoms (scar impingement) with shooting pain. Overall, however, no uniform pain pattern can be described for arthrofibrosis. Except for an obligatory restriction of movement, the joint can be completely free of pain.

In primary arthrofibrosis, pain is usually experienced when an attempt is made to overcome the scarred, fixed final position of the joint. Less frequently, patients also complain of pain at the rest of the joint as an indication of an ongoing inflammatory process of the joint. Clinical picture (symptoms and complaints) of arthrofibrosis is, therefore, very heterogeneous (diverse).

Pain in arthrofibrosis

Pain usually occurs in connection with arthrofibrosis of the knee joint. In most cases, the patient can also assign the pain exactly to the knee joint and, after more specific examinations, specify more precisely in which area the pain occurs. Sometimes, however, pain radiates. Similarly, pain in the hip can occur as a result of a relieving posture or incorrect weight-bearing, and one must look more specifically for the cause in the knee joint and not in the hip.

The pain is often motion-dependent, which means that the pain is more likely to occur when the knee is loaded, for example, when standing or walking. In relaxed positions when sitting or lying down, when the knee is not moved, the pain does not occur or occurs less in comparison.

Often the pain responds well to the use of painkillers so that the pain can be relieved with appropriate medication.

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Therapy of arthrofibrosis

The therapy of secondary arthrofibrosis is surgical. Individual scar strands can be easily removed arthroscopically, thus removing the mechanical obstacle. In cruciate ligament surgery, space can be made available for the misplaced graft by expanding the knee roof (emergency plastic surgery), thus preventing the graft from striking again.

The therapy of primary arthrofibrosis is far more complicated and less successful.

In contrast to secondary arthrofibrosis, it often cannot be repaired arthroscopically. In the worst case, multiple arthroscopic operations, in particular, can lead to further activation of the chronically occurring inflammatory processes.

The use of arthroscopic surgery in symptomatic conservative therapy is one of the most critical aspects of arthroscopic surgery:

  • Physiotherapy/physiotherapy
  • NSAIDs (non-steroidal anti-rheumatic drugs)
  • Physical therapy (heat, cold, electrotherapy, ultrasound, etc.)

While secondary arthrofibrosis is usually caused by manual surgical errors, the cause of primary arthrofibrosis is still not fully understood. Different research results are contrasted with each other. It seems inevitable, however, that several factors are responsible for triggering and maintaining primary arthrofibrosis.

In secondary arthrofibrosis following cruciate ligament replacement surgery, manual surgical errors are decisive for a persistent restriction of knee joint movement.

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For example, incorrect graft placement can lead to the graft being trapped (impingement) on the roof of the knee joint when the knee is extended. This problem, which can be observed quite frequently, is caused by a tibial drill channel placed too far forward. Repeated incarcerations during knee extension continuously damage the graft, which can ultimately lead to spherical scarring on the graft (cyclops syndrome). The ability to stretch the knee joint is limited.

In the area of the ankle joints, a capsule/ligament rupture in the context of a twisting trauma (accident event) occasionally leads to intra-articular (in the joint) scarring in the area of the injured structure or generalized. In this respect, the transition from secondary arthrofibrosis to primary arthrofibrosis can be fluid.

Primary arthrofibrosis is characterized by scarring that involves the entire joint (multiplication of connective tissue).

This quantitative component is accompanied by the fact that the connective tissue formed is also altered in its composition. Connective tissue fibers are cross-linked with each other, which further reduces joint mobility.

The following causes of excessive scar formation are discussed:

  • Activation and proliferation of fibroblasts (connective tissue cells) during an initial inflammatory process
  • Chronic inflammatory reaction as part of an immunoreactive process.
  • Dysbalances in cytokines (inflammatory messengers).
  • Hypoxia – reperfusion damage – theory
  • Circulatory problem
  • Genetic factors

To date, it has not been clarified by which stimuli and in which patients primary arthrofibrosis occurs. However, retrospective observations after cruciate ligament arthroplasty could identify risk factors that led to concrete recommendations for the prophylaxis of arthrofibrosis.

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Arthrofibrosis after knee TEP

Arthrofibrosis in the knee joint is a relatively common consequence after surgical interventions on the knee joint (arthroscopic interventions). Such operations also include knee TEP (total endoprosthesis of the knee joint).

With a knee TEP, the knee joint is replaced by an artificial knee joint. This can lead to arthrofibrosis as a result of the operation. This means that increased scar tissue is formed, which limits the function of the knee joint. A few days to weeks after the operation, the knee joint stiffens up, causing increased pain and difficulty under stress or insufficient mobility in the knee joint.

There are various forms of treatment to maintain or promote the mobility of the knee. Firstly, regular exercise therapy should be carried out as a preventive measure.

The movement and load on the joint reduces the strong formation of scar tissue after the operation. If severe scarring and limited movement have already occurred, therapy can be carried out as in other cases of arthrofibrosis (physiotherapy, anesthetic mobilization, surgical removal of scar tissue).

Differential diagnoses (alternative causes)

Other clinical pictures must be distinguished from arthrofibrosis, which can also lead to a loss of knee joint function.

Inadequate post-operative follow-up treatment and too prolonged immobilization can lead to capsule shrinkage of the knee joint, resulting in a persistent restriction of movement. The reasons for this are insufficient post-operative pain elimination, whereby progress in physiotherapy is made more difficult due to pain, and a lack of motivation and education of the patient about the importance of post-operative physiotherapy, physical therapy, medical training therapy, etc.

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MRI of the knee joint

The imaging procedure of choice for the knee joint is the standard X-ray. This allows the joint and possible changes in the joint space to be assessed. If the cartilage, meniscus, or capsule-ligament apparatus are to be better assessed, an MRI (magnetic resonance imaging) is the method of choice.

This makes an MRI instead an additional diagnostic option. In the case of arthrofibrosis of the knee joint, it is particularly useful that the joints and possible changes can be well depicted in the MRI. Thus a diagnosis can usually be made with great certainty.

How can arthrofibrosis be prevented?

Due to the problematic therapy of an arthrofibrosis that has only just occurred, the prophylaxis of this disease is of particular importance. In particular, we investigated which precautionary measures can minimize the risk of arthrofibrosis after cruciate ligament replacement.

Preoperative prophylaxis

After a traumatic rupture of the cruciate ligament, surgery should not be performed too soon. Several studies had shown that the risk of developing arthrofibrosis was significantly increased in the first three weeks after the accident when a cruciate ligament replacement operation was performed.

A general “joint irritation” (acute traumatic, inflammatory reaction) caused by the trauma is seen as the cause for this, with the risk of transition to chronic joint inflammation due to additional surgical traumatization.

A recovery period of about six weeks before the operation is recommended. At the time of surgery, the knee joint should be freely movable and “non-irritant” (painless, no joint effusion). Accompanying injuries (especially injuries to the inner ligament) should have been treated beforehand. If the knee joint is free of irritation, physiotherapy can be started preoperatively.

The patient must be informed about the severity of the injury and the consequences resulting from it, especially post-operative follow-up treatment, and motivated to cooperate.

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Intraoperative prophylaxis

A surgical misplacement of the cruciate ligament graft must be avoided at all costs. A frequent mistake is too far forward (ventrally) placed the tibial (tibial) drill channel. Other possible errors are a too traumatic or prolonged operation, a misplacement of the femoral drill channel, and a faulty graft fixation.

Post-operative prophylaxis

Physiotherapy should be started immediately after the operation. An adequate elimination of pain with suitable analgesics is necessary for this. Active and passive (motor splint) movement exercises and exercises for patella mobilization are used.

The patient must be motivated to cooperate.

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