Arthrofibrosis (from
Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
: ''arthro-'' joint, ''fibrosis'' – scar tissue formation) has been described in most joints like knee, hip, ankle, foot joints, shoulder (
frozen shoulder,
adhesive capsulitis), elbow (stiff elbow), wrist, hand joints as well as spinal vertebrae. It can occur after injury or surgery or may arise without an obvious cause. There is excessive scar tissue formation within the joint and/or surrounding soft tissues leading to painful restriction of joint motion that persists despite physical therapy and rehabilitation. The scar tissue may be located inside the knee joint or may involve the
soft tissue
Soft tissue connective tissue, connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, Adipose tissue, fat, fibrous tissue, Lymphatic vessel, lymph and blood vessels, fasciae, and synovial membranes.� ...
structures around the knee joint, or both locations.
The pathology that causes arthrofibrosis also causes other forms of
fibrosis. Injury and inflammation activates
fibroblasts
A fibroblast is a type of biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibrobla ...
and other cell types, turning them into
myofibroblasts which create scar tissue and more inflammation.
Arthrofibrosis of the knee (frozen knee)
Arthrofibrosis of the knee, also known as "frozen knee", has been one of the more studied joints as a result of its frequency of occurrence.
Arthrofibrosis can follow knee injury and knee surgeries like arthroscopic knee surgery or
knee replacement
Knee replacement, also known as knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability, most commonly offered when joint pain is not diminished by conservative sources. ...
.
Scar tissue can cause structures of the knee to become contracted, restricting normal motion. Depending on the site of scarring,
knee cap mobility and/or joint
range of motion
Range of motion (or ROM) is the linear or angular distance that a moving object may normally travel while properly attached to another.
In biomechanics and strength training, ROM refers to the angular distance and direction a joint can move be ...
(i.e.
flexion
Motion, the process of movement, is described using specific anatomical terminology, anatomical terms. Motion includes movement of Organ (anatomy), organs, joints, Limb (anatomy), limbs, and specific sections of the body. The terminology used de ...
,
extension, or both) may be affected. Symptoms experienced as a result of arthrofibrosis of the knee include stiffness, pain, limping, heat, swelling,
crepitus, and/or weakness.
Clinical diagnosis may also include the use of
magnetic resonance imaging (or MRI) to visualize the knee compartments affected. The consequent
pain
Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...
may lead to the cascade of
quadriceps
The quadriceps femoris muscle (, also called the quadriceps extensor, quadriceps or quads) is a large muscle group that includes the four prevailing muscles on the front of the thigh. It is the sole extensor muscle of the knee, forming a large ...
weakness,
patellar tendon
The patellar tendon is the distal portion of the common tendon of the quadriceps femoris, which is continued from the patella to the tibial tuberosity. It is also sometimes called the patellar ligament as it forms a bone to bone connection whe ...
shortening and scarring in the tissues around the
knee cap—with an end stage of permanent
patella infera—where the
knee cap is pulled down into an abnormal position where it becomes vulnerable to joint surface damage.
Arthrofibrosis after knee injury, knee arthroscopy or other surgeries
The first step in treating arthrofibrosis is appropriately directed
physical therapy
Physical therapy (PT), also known as physiotherapy, is a healthcare profession, as well as the care provided by physical therapists who promote, maintain, or restore health through patient education, physical intervention, disease preventio ...
with a focus on icing and elevating and passive stretching exercises such as continuous passive motion (CPM).
Passive stretching can increase range of motion if conducted frequently and carefully so that tissues are not torn.
There are a number of treatment options and treatment varies depending on the knowledge of the treating clinician and on the cause and duration of the fibrosis. Often physical therapy is used as an attempt at conservative management. Knowledge of the role of inflammation in arthrofibrosis has led a cautionary approach to exercise, because exercise increases inflammation. Advice to AF patients now typically consists of "listen to your knee" and stop, or reduce, activities that increase pain during and after exercise.
Aggressive exercise of the affected limb may cause permanent damage.
If physical therapy fails options include manipulation under anaesthesia (MUA), arthroscopic lysis of adhesions and open lysis of adhesions. Although MUA and surgery can be successful, the resulting increase in inflammation may cause scar tissue to rapidly return and symptoms can worsen.
Pharmacological interventions such as anti-inflammatory medications and supplements are increasingly used to treat arthrofibrosis. Biologics that reduce the signalling of the major inflammatory cytokines TNF-α (Simponi, Humira) and IL-1β (anakinra) are promising treatments.
Consultation with a rheumatologist can help to determine appropriate medications.
After knee replacement
Arthrofibrosis can occur after total knee replacement or partial knee replacement, when excessive scar tissue (
collagen
Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...
fibril) deposition occurs in and around the knee. This can be accompanied by shortening of the patellar tendon (patella baja/infera) which can also contribute to limited flexion. The rates of AF after TKA vary widely in the literature as there is no standard definition. One study's definition is a total range of motion (ROM) <90 degrees constitutes AF, another definition is flexion contracture >10 degrees, or inability to flex the knee >100 degrees. AF is a diagnosis of exclusion; before making a final diagnosis of arthrofibrosis, other causes of stiffness following knee replacement should be excluded (ex: infection, malposition of the implants, or mechanical block to motion).
In the case of AF after total knee arthroplasty (TKA) management traditionally consisted of aggressive physical therapy, and in the case that failed, manipulation under anesthesia (MUA). As discussed above, aggressive exercise is now avoided. The rates of MUA after TKA vary widely. There are several reasons for this: there is no definite consensus to when a MUA is required (different surgeons follow different indications), there is no standardized definition of arthrofibrosis (see above), and MUA is not always a reliable treatment. MUAs can lead to adverse outcomes, including fractures, rupture of tendons, damage to the prosthesis, heterotrophic ossification, muscle tears and bleeding and the return of scar tissue.
For these reasons treatment patterns vary widely. MUA after TKA is more likely to be to be successful if performed in the first 8–12 weeks after surgery. After 12 weeks manipulation is much less likely to have an acceptable outcome.
If the fibrosis is chronic (more than 12 weeks) there is a decreased likelihood of success with MUA, and open lysis of adhesions is sometime performed. However, this carries with it the attendant risks of another open procedure (i.e., infection, blood clots, blood loss, etc.) and the return of scar tissue.
References
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External links
* https://arthrofibrosis.info
* http://www.kneeguru.co.uk/KNEEnotes/primers/complications-rehabilitation/key-arthrofibrosis-resources-kneeguru-site
Gross pathology