According to abbreviationfinder, the Hoffa-Kastert syndrome manifests itself in a thickening (hypertrophy) of the Hoffa fat pad, which extends within the knee joint capsule from the lower edge of the kneecap to the tibial plateau. As a soft, elastic structure, it can be easily felt from the outside. The hypertrophy of Hoffa’s fat pad is not an independent disease, but usually represents an inflammatory reaction to recurring or one-off traumatic effects on the knee or to inflammatory processes in the knee joint.
What is Hoffa-Kastert Syndrome?
Hoffa-Kastert syndrome is characterized by hypertrophy of Hoffa’s fat pad in the knee joint. The Hoffa fat pad (corpus adiposum infrapatellare) is located within the knee joint capsule and extends from the lower edge of the kneecap (patella) to the tibia head. The structure is not only used for padding – similar to bursae – but also fulfills a variety of sensorimotor tasks.
It is therefore intensively supplied with blood and innervated by a network of fast-conducting C-fibers. In 1904, the orthopedist Albert Hoffa was the first to describe hypertrophy of the fat body as an independent disease. It was not until 50 years later that the surgeon Josef Kastert postulated that hypertrophy of the fat pad is usually associated with lesions in the knee, such as meniscus or cartilage damage, or with inflammation of certain structures in the knee.
The original term Hoffa’s disease for hypertrophy of the infrapatellar corpus adiposum was replaced by the term Hoffa-Kastert syndrome, which more accurately represents the medical situation.
The large number of sensorimotor tasks of the Hoffa fat pad, which it is responsible for in addition to its mechanical cushioning and shifting function, causes its complex and sensitive fine structure. The fat body constantly sends feedback to the brain about movement sequences in the knee, so that motor correction instructions are unconsciously sent to the affected muscle parts on the basis of the reports.
With regard to its sensorimotor tasks, the Hoffa fat pad also supports the proprioceptive system, which enables the perception and coordination of the position of the body and its limbs in three-dimensional space. The corpus adiposum infrapatellare reacts very sensitively to recurring external pressure stimuli and to unusual movements or injuries in the knee.
This often triggers inflammatory reactions. Inflammatory reactions can also occur if other structures in the knee joint are inflamed. The fat body is interspersed with immune cells that can be activated by messenger substances from other immune cells in the surrounding structures. Inflammatory reactions in the fat body lead to its hypertrophy.
Symptoms, Ailments & Signs
Inflammatory reactions in the infrapatellar corpus adiposum and the associated hypertrophy of the structure lead to restricted movement of the knee, with flexion being particularly affected. There is a soft resistance against bending of the knee. This clearly distinguishes the symptoms from meniscus damage, which leads to a harder and more accentuated blockage of the joint.
The symptoms are accompanied by increasing pain in the knee. Above all, tension pains appear when attempting to bend. Typically, lumps of soft to firm texture are seen on either side of the patellar ligament.
The visible and palpable swellings are sensitive to pressure. In many cases, but not always, the knee swells up overall, making the typical symptoms of Hoffa-Kastert syndrome less noticeable.
Diagnosis & disease progression
At the beginning of a diagnosis to be made, the focus is on recording the visible and palpable symptoms and the pain pattern (clinical examination). The anamnesis is also important, as it can provide information about the onset and cause of the symptoms.
If the diagnosis made in this way leaves questions unanswered that need to be clarified before determining therapy, imaging methods such as X -rays, magnetic resonance imaging (MRI) and computed tomography (CT) can be considered. Depending on the findings, knee arthroscopy may be an option, during which a diagnosis can be made more precise and a minimally invasive surgical procedure is carried out at the same time.
The course of the disease in Hoffa-Kastert syndrome depends primarily on the underlying disease that caused it, which often consists of a lesion of certain structures in the knee. If the hypertrophy of the fat body persists over a long period of time, a fibrous remodeling takes place in the structure.
There is increased incorporation of collagen fibers, which harden the corpus adiposum and lead to significant functional limitations. In the further course, calcium deposits or ossifications can even occur within the fat body, which can severely limit the joint function of the knee.
The Hoffa-Kastert syndrome causes various complaints and symptoms that can occur in the knee area. Various inflammations and infections develop, which can severely restrict the patient’s everyday life and movement. Above all, the usual bending is no longer possible due to the Hoffa-Kastert syndrome or is usually associated with relatively severe pain.
The affected person is no longer resilient and can no longer carry out any sporting activities. The pain can also occur in the form of rest pain and can also lead to sleep problems at night. It is not uncommon for swelling to occur and the constant pain to develop negative psychological symptoms. Patients can thus develop depression and other mental disorders.
The treatment of Hoffa-Kastert syndrome is always causal and rarely associated with complications. The underlying disease is treated in particular, although in some cases surgical intervention is also necessary. This is associated with the usual complications and risks of an operation. The life expectancy of the patient is not affected by the Hoffa-Kastert syndrome. After the treatment, there are usually no further complaints.
When should you go to the doctor?
Hoffa-Kastert syndrome always requires a visit to a doctor. This disease does not heal itself and the symptoms usually worsen if no treatment is initiated. Patients with Hoffa-Kastert syndrome must see a doctor if they experience severe pain and swelling in the knee area. These are usually accompanied by movement restrictions, which can also lead to sensory disturbances.
Persistent pain in the knees in particular is often an indication of Hoffa-Kastert syndrome, which should be the reason for a doctor’s visit. The swelling does not go away on its own and is often visible to the naked eye. A medical examination is particularly necessary after external violence or an accident. In acute emergencies, the hospital can be visited with Hoffa-Kastert syndrome. Furthermore, the general practitioner or an orthopedist can identify the Hoffa-Kastert syndrome and initiate treatment. The course of the disease is usually positive.
Treatment & Therapy
Treatment of Hoffa-Kastert syndrome is primarily aimed at improving the underlying disease that caused it. Underlying diseases can be, for example, damage to the meniscus or lesions in one or more ligaments. Fractures or diseases of the articular cartilage can also trigger an inflammatory reaction in the fat body.
In those cases in which a primary damage in the knee could be recognized and successfully treated, the Hoffa-Kastert syndrome regresses on its own. This does not result in any lasting reduction in functionality. In exceptional cases, in which fibrous structures in the form of villi have already formed and are pinching the joint space, a partial resection of the fat pad is performed in order to restore the mobility of the knee.
In some cases, it is also necessary to perform a partial resection because the fat pad obstructs access to the structure whose damage is to be repaired by arthroscopy. In general, resections or partial resections of the fat pad are performed more cautiously than in the past, in order to impair the diverse functions of the infrapatellar corpus adiposum as little as possible.
Outlook & Forecast
The prognosis of Hoffa-Kastert syndrome is generally favorable. In a large number of cases, the underlying disease can be completely cured. At the same time, this leads to a healing of the Hoffa-Kastert syndrome. In order to have a good chance of recovery, an early and accurate diagnosis is required. If this is the case, freedom from symptoms can be achieved within a few weeks or months with optimal therapy. If no further complications occur, no consequential damage is to be expected after completion of the treatment. There are no impairments and the knee can gradually be fully loaded again.
If, during the course of recovery, there is a restriction in mobility, the otherwise very favorable prognosis deteriorates. In some patients, fibrous structures can form on the knee. These must be removed in a further treatment so that full mobility of the joint is restored. In addition, the underlying disease can lead to a need for surgical intervention. Because any surgery involves risk, there is a possibility of further injury or damage. In the best-case scenario, the wound heals quickly and the patient recovers quickly after an operation. If this is the case, the Hoffa-Kastert syndrome regresses on its own.
If the knee is injured again, the syndrome can develop over the course of life. The prognosis is also favorable in the event of a recurrence.
Because Hoffa-Kastert syndrome is usually caused by lesions or inflammation in other structures of the knee, there are no direct preventive behaviors that could prevent the disease from occurring. The best prevention is to protect the knee from injuries, improper strain and overload.
In the case of Hoffa-Kastert syndrome, the aftercare measures are very limited or even not possible at all. The person concerned is primarily dependent on a quick and early diagnosis and treatment. This is the only way to prevent further complications or a further deterioration of the symptoms.
The symptoms of Hoffa-Kastert syndrome cannot always be completely alleviated, so that complete healing is not always possible. As a rule, the underlying disease that is responsible for the inflammatory reaction must first be identified. Only then can the symptoms be alleviated. In many cases, Hoffa-Kastert syndrome therefore also requires surgical intervention.
After such an operation, the person concerned should take it easy and not carry out any strenuous activities. Stressful activities should also be avoided. It is not uncommon for physiotherapy measures to be useful. Many exercises can also be carried out at home, which increases mobility again.
Some of those affected also depend on the help and support of friends and acquaintances. The Hoffa-Kastert syndrome does not reduce the life expectancy of those affected. Contact with other patients can also be useful, as this leads to an exchange of information.
You can do that yourself
The medical treatment of Hoffa-Kastert syndrome can be supported by those affected by rest and moderate exercise. Accompanying this, physiotherapeutic treatment is usually initiated, which the patients can supplement with individual exercises at home. The responsible sports physician or physiotherapist can answer the detailed measures to be taken.
In addition to these general therapeutic measures aimed at relieving the symptoms, the accompanying symptoms themselves can be alleviated. Targeted massages as well as rest and cooling are recommended for pain in the knee. Sometimes natural pain relievers such as marigold ointment or extracts from devil’s claw also help. These remedies also help with tension pain and similar complaints in the knee area. Wraps and cooling pads have proven effective for swelling and bruising. If mobility is restricted, aids such as crutches or a wheelchair can be used. In less severe cases, it is usually sufficient to reduce the load on the affected leg.
If you have other symptoms or if the measures mentioned are ineffective, you should talk to your doctor again. Although the Hoffa-Kastert syndrome is usually not a serious illness, unusual symptoms must be clarified.