Hoffa-Kastert Syndrome: Causes, Symptoms & Treatment

Hoffa-Kastert syndrome manifests as a thickening (hypertrophy) of the Hoffa fat body, which extends within the knee joint capsule from the lower edge of the patella to the tibial plateau. It is easily palpable from the outside as a soft elastic structure. Hypertrophy of the Hoffa fat body is not a disease in its own right, but usually represents an inflammatory response to recurrent or single traumatic impacts to the knee or to inflammatory processes in the knee joint.

What is Hoffa-Kastert syndrome?

Hoffa-Kastert syndrome is characterized by hypertrophy of the Hoffa fat body in the knee joint. The Hoffa fat body (corpus adiposum infrapatellare) is located within the knee joint capsule and extends from the lower edge of the kneecap (patella) to the tibial plateau. Similar to bursae, the structure not only serves as padding, but also fulfills a variety of sensorimotor functions. It is therefore intensively supplied with blood and innervated by a network of fast-conducting C-fibers. The orthopedist Albert Hoffa first described hypertrophy of the fat body as an independent disease in 1904. It was not until 50 years later that surgeon Josef Kastert postulated that hypertrophy of the fat body was usually associated with lesions in the knee such as meniscal or cartilage damage or with inflammation of specific structures in the knee. The original term Hoffa’s disease for hypertrophy of the corpus adiposum infrapatellare has been substituted by the term Hoffa-Kastert syndrome, which more aptly represents the medical facts.

Causes

The multitude of sensorimotor tasks performed by the Hoffa fat body, in addition to its mechanical cushioning and displacement function, conditions its complex and delicate fine structure. The adipose body constantly provides feedback to the brain about movement sequences in the knee, so that motor correction instructions are unconsciously given to the relevant muscle parts on the basis of the messages. With regard to its sensorimotor tasks, the Hoffa fat body 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 is very sensitive to recurrent external pressure stimuli and to unusual movements or injuries in the knee. Inflammatory reactions are often triggered as a result. Inflammatory reactions may 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 surrounding structures. Inflammatory reactions in the fat body lead to its hypertrophy.

Symptoms, complaints, and signs

Inflammatory reactions in the corpus adiposum infrapatellare and the associated hypertrophy of the structure lead to restricted knee motion, with flexion being particularly affected. Soft resistance to angulation of the knee develops. In this, the symptoms differ markedly from meniscal damage, which leads to a harder and more accentuated blockage of the joint. The symptoms are accompanied by increasing pain in the knee. Most notably, tension pain is evident when attempting flexion. Typically, bulging swellings with soft to coarse texture are seen on both sides of the patellar ligament. The visible and palpable swellings are tender to pressure. In many cases, but not always, the knee swells overall, making the typical symptoms of Hoffa-Kastert syndrome less obvious.

Diagnosis and course of the disease

At the beginning of a diagnosis to be made, the main focus is on recording the visible and palpable symptoms and the pain patterns (clinical examination). The medical history, which can provide information about the onset and cause of the complaints, is also important. If the diagnosis made in this way leaves questions unanswered that need to be clarified before determining a therapy, imaging procedures such as X-ray, magnetic resonance imaging (MRI) and computer tomography (CT) may 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 performed at the same time. The course of the disease Hoffa-Kastert syndrome depends mainly on the causative underlying disease, which often consists of a lesion of certain structures in the knee.If the hypertrophy of the fat body is maintained for a long time, fibrous remodeling initially takes place in the structure. This results in the increased incorporation of collagen fibers, which harden the corpus adiposum and lead to significant functional restriction. As it progresses, calcification or ossification may even occur within the adipose body, which can severely limit the joint function of the knee.

Complications

Hoffa-Kastert syndrome results in various complaints and symptoms that can occur in the area of the knee. Various inflammations and infections develop, which can severely limit the patient’s daily life and movement. Above all, ordinary bending is no longer possible due to Hoffa-Kastert syndrome or is usually associated with relatively severe pain. The affected person is no longer able to bear weight and can no longer perform any sporting activities. The pain can also occur in the form of pain at rest, leading to sleep problems at night. It is not uncommon for swelling to occur and for negative psychological symptoms to develop as a result of the constant pain. Patients may thus suffer from depression and other psychological upsets. The treatment of Hoffa-Kastert syndrome is always causal and is rarely associated with complications. The primary treatment is the underlying disease, and in some cases surgery is necessary. This is associated with the usual complications and risks of surgery. The patient’s life expectancy is not affected by Hoffa-Kastert syndrome. After treatment, there are usually no further symptoms.

When should you see a doctor?

Hoffa-Kastert syndrome always requires a visit to a doctor. There is no self-healing in this condition and usually worsening of symptoms if treatment is not initiated. Patients need to see a doctor in Hoffa-Kastert syndrome when there is severe pain and swelling in the knee area. These are usually also accompanied by restricted movement, and sensory disturbances may also occur. Frequently, especially permanent pain in the knees indicates Hoffa-Kastert syndrome, which should be reason for a visit to the doctor. The swellings do not disappear by themselves and are often visible to the naked eye. Especially after external violence or after an accident, a medical examination is necessary. In acute emergencies, the hospital can be visited for Hoffa-Kastert syndrome. Furthermore, the general practitioner or an orthopedist can also identify Hoffa-Kastert syndrome and initiate treatment. There is usually a positive course of the disease.

Treatment and therapy

Treatment of Hoffa-Kastert syndrome is primarily aimed at ameliorating the underlying disease causing the condition. Underlying conditions may include damage to the meniscus or lesions of one or more ligaments. Fractures or diseases of the articular cartilage can also be the trigger for an inflammatory reaction of the fat body. In cases where primary damage to the knee has been identified and successfully treated, Hoffa-Kastert syndrome regresses on its own. This does not result in lasting functional impairments. In exceptional cases where fibrous structures in the form of villi have already formed and are constricting the joint space, a partial resection of the fatty body is performed to restore knee mobility. In some cases, it is also necessary to perform a partial resection because the fat body obstructs access to the structure whose damage is to be repaired by arthroscopy. In general, resections or partial resections of the fat body are performed more cautiously than in the past to minimize interference with the multiple functions of the corpus adiposum infrapatellare.

Outlook and prognosis

The prognosis of Hoffa-Kastert syndrome is generally favorable. In a large number of cases, the underlying disease present can be completely cured. This simultaneously leads to a cure of Hoffa-Kastert syndrome. In order for there to be a good chance of a cure, an early and accurate diagnosis is required. If this is given, 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 there is a restriction of movement within the course of recovery, the otherwise very favorable prognosis deteriorates. In some patients, fibrous structures may form on the knee. These must be removed in further treatment to restore full range of motion to the joint. In addition, the underlying condition may result in the need for surgical intervention. Since any surgery carries risks, there is a possibility of further injury or damage. Optimally, after surgery, there is rapid wound healing as well as recovery of the patient. If this is the case, Hoffa-Kastert syndrome will regress on its own. In case of a recurrence of the knee injury, the syndrome may develop in the course of life. The prognosis is also favorable if it recurs.

Prevention

Because Hoffa-Kastert syndrome is usually caused by lesions or inflammation of other structures of the knee, no directly preventive behaviors exist to prevent the disease from occurring. The best prevention is to protect the knee from injury, misuse, and overuse.

Aftercare

In Hoffa-Kastert syndrome, aftercare measures are very limited or even impossible. In this case, the affected person is primarily dependent on a rapid diagnosis and treatment at an early stage. This is the only way to prevent further complications or a further worsening of the symptoms. The symptoms of Hoffa-Kastert syndrome cannot always be completely alleviated, so that a complete cure is not always possible. As a rule, the underlying disease responsible for the inflammatory reaction must first be identified. Only then can the symptoms be alleviated. In many cases, Hoffa-Kastert syndrome therefore requires surgical intervention. After such an operation, the affected person should take it easy and not perform any strenuous activities. Stressful activities should also be avoided. It is not uncommon for physiotherapy measures to be useful. Many exercises can be performed in the patient’s own home, thus increasing mobility again. Some patients are also dependent on the help and support of friends and acquaintances. Hoffa-Kastert syndrome does not reduce the life expectancy of the affected person. Contact with other patients can also be useful, as this leads to an exchange of information.

What you can do yourself

Medical treatment of Hoffa-Kastert syndrome can be supported by the affected person through sparing and moderate exercise. This is usually accompanied by physiotherapy treatment, which patients can supplement with individual exercises at home. The sports physician or physiotherapist in charge can answer the question of which measures to take in detail. In addition to these general therapeutic measures aimed at alleviating the symptoms, the accompanying symptoms themselves can be alleviated. For pain in the knee, targeted massages are recommended, as well as rest and cooling. Sometimes natural painkillers such as calendula ointment or extracts from devil’s claw also help. These remedies also help with tension pain and similar complaints in the area of the knee. For swelling and bruising, wraps and cooling compresses have proven effective. If movement 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 further complaints occur or the above-mentioned measures do not have any effect, the doctor should be consulted again. Although Hoffa-Kastert syndrome is usually not a serious illness, unusual symptoms must still be clarified.