Heterotopic ossification
| Classification according to ICD-10 | |
|---|---|
| M61 | Calcification and ossification of muscles |
| M61.0 | Traumatic myositis ossificans |
| M61.2 | Calcification and ossification of muscles in paralysis |
| M61.3 | Calcification and ossification of muscles in burns |
| ICD-10 online (WHO version 2019) | |
As heterotopic ossification of the reconstruction of soft tissue is outside the skeletal system in bony tissue called, interchangeably, the term comes myositis ossificans used.
causes
Heterotopic ossifications are generally the result of tissue damage. They are most often seen after hip joint replacement . However, they also occur in a number of other diseases or injuries, primarily fractures of large bones near the joints such as femoral neck fractures or shoulder joint fractures . Post-traumatic ossification is also very common on the elbow, which occurs in up to 55% after elbow dislocations , in up to 30% in fractures of the radial head and in up to 20% in supracondylar fractures of the humerus. Heterotopic ossifications often occur in explosion injuries due to the severe tissue injuries, as well as in polytrauma with prolonged unconsciousness.
In addition, neurogenic heterotopic ossifications are observed especially after a traumatic brain injury , a spinal cord injury (and especially in the case of paraplegia ), encephalitis or a peripheral plexus or nerve injury.
A third large group are ossifications in competitive athletes and in massive, repetitive muscular overuse. Examples are ossifications in the adductor muscles and gluteal muscles on the thigh in riders or calcifications on the tensor fasciae latae muscle in sprint athletes. Heterotopic ossifications can also be observed in some chronic degenerative diseases and in some rheumatic diseases such as Bechterew's disease .
Pathogenesis
Pathogenetically , so-called mesenchymal precursor cells are mostly responsible for the ossifications that develop outside the skeleton . Stimulated by so-called morphogens - the concentration of which increases sharply in the muscle and soft tissue area after trauma and operations - these cells can be transformed into osteoblasts via various intermediate stages or even trigger the transformation of myoblasts into osteoblasts. The ossification takes place endochondrally from previously cartilaginous tissue, then a lamellar bone is created.
About ten to twelve days after the operation or the trauma, the incipient ossification can become clinically noticeable through pain, swelling and reddening of the skin (usually without any laboratory signs of inflammation). After three to six weeks, they are initially visible radiologically as faint, indistinctly delimited shadows, but before that they can already be shown in the scintigraphy. The heterotopic ossifications are gradually rebuilt from their center to the periphery into solid bone substance, but their growth comes to a standstill after a while. After six months, most of the ossifications are mature, but growth of up to 20% can be seen up to a year later.
Diagnosis
As a rule, heterotopic ossifications are already clearly visible in conventional x-rays: when projected onto the affected muscle and soft tissue, there are partially faint, but later also easily delimited, lime-thick shadows . Computed tomography , magnetic resonance tomography and sonography are used for the precise localization of the ossifications and the assessment of their extent in the context of therapy planning . By scintigraphy can be determined whether the ossification are "grown" and then show no increased bone metabolism more, or are still in the process of growth and maturation represent a much higher metabolism. This is important when planning a surgical resection, as this should only be done after maturation is complete in order to reduce the risk of recurrence.
Symptoms and frequency
Heterotopic ossifications can remain completely asymptomatic , but they can also cause pain and pain-related or mechanical movement restrictions of all degrees of severity. The extent of the radiologically visible ossifications does not correlate with the extent of the complaints. If heterotopic ossifications occur after hip joint prosthesis implantation - the frequency is stated very differently in the literature with 2 to 70 percent - they lead to a stiffening ( ankylosis ) of the hip joint in around 4 percent . After severe hip joint injuries, severe joint-bridging ossifications with stiffening are observed much more frequently (around 15 percent). Disruptive heterotopic ossifications are rarely observed after the implantation of knee joint prostheses; Often (around 15 percent) there are small, clinically harmless ossifications in the course of the quadriceps tendon .
Postoperative heterotopic ossifications are naturally more common in the older age groups, in which the need for endoprostheses increases. The formation of heterotopic ossifications after bone and joint injuries, on the other hand, is independent of age; in these cases, however, it cannot be determined whether the injury itself or the operative therapy is the cause of the ossification.
The development of heterotopic ossifications depends on an individual predisposition. It is not known which factors this predisposition is based on. Individuals who are known to be predisposed to increased bony metaplasia (e.g. patients with ankylosing spondylitis ( Bechterew disease ) or diseases from the group of disseminated idiopathic skeletal hyperostoses ) are preferably affected by heterotopic ossifications. Heterotopic ossifications are also observed more frequently in men than in women.
Other predisposing factors are profuse intraoperative bleeding and bruising as well as infections. The type of surgical approach and the surgical technique also seem to have an influence on the frequency. In particular, further tissue trauma through vigorous movements of the bone fracture ends towards each other or through abrupt repositioning movements increases the risk of heterotopic ossifications, as does delayed surgical treatment. On the other hand, the rehabilitation has no influence on the frequency; it is independent of whether the joint concerned is immobilized, active or passive.
Heterotopic ossifications after hip replacement
Heterotopic ossifications after hip replacement with endoprostheses are classified by means of the classification according to Brooker (1973) using an X-ray image in the frontal plane and divided into four grades:
- Individual, non-contiguous small calcifications in the tissue near the joint
- Ossifications that start from the large roll mound or the ischium, but still leave a gap of at least one centimeter
- Ossifications from the large roll mound or the ischium, but with a gap of less than one centimeter
- Ankylosis, the ossification bridging the joint, which firmly connects the large rolling hillock with the ischium
The disadvantage of this classification is that the complex three-dimensional structure is only classified using a single two-dimensional X-ray image. According to Rader and Barthel, ossifications with clinically relevant symptoms were found in 10 to 20 percent of patients.
treatment
Asymptomatic heterotopic ossifications usually do not require treatment. In the case of movement disorders and / or chronic pain, surgical removal of the calcifications must be considered. It should not be ignored here that any surgical manipulation can itself be the cause of new ossifications. Surgical removal of the ossifications often does not achieve the treatment goal of improving objective mobility or subjective pain perception.
The timing of a resection or arthrolysis is controversial. On the one hand, there are indications of a significantly increased risk of recurrence if the ossifications are not yet "mature" and are still growing at the time of removal, on the other hand, the functional results appear to be better, especially on the elbow and shoulder joints, if the operation is carried out in the first six months. The functional results appear better after resection of heterotopic ossifications that have formed after traumatic brain injury.
prevention
Patients in whom the occurrence of heterotopic ossifications is already known due to previous interventions or trauma are often subjected to radiation shortly before or within three days after a planned major bone operation (hip prosthesis) , which increases the probability of renewed heterotopic ossifications of about 30 10-14% reduced.
Indomethacin has long been used for the prophylaxis of heterotopic ossifications. In recent years, high-dose non-steroidal anti-inflammatory drugs such as ibuprofen or diclofenac have also been used for this purpose. These can also help reduce the incidence of heterotopic ossification, so they are usually administered for several weeks after major orthopedic surgery regardless of a patient's need for analgesics.
Individual evidence
- ^ A b F. W. Koch: Heterotopic postoperative ossifications . In: K. Peters (Ed.): Bone Diseases: Clinic, Diagnosis, Therapy . Steinkopf, Darmstadt 2002, ISBN 3-7985-1325-2 , p. 151-154 .
- ^ FJ Seibert, R. Szyszkowitz, G. Schippinger: Trauma and trauma consequences . In: Christian Tschauner (Ed.): The hip . Enke-Verlag, Stuttgart 1997, ISBN 3-432-29981-8 , p. 301 ff.
- ^ Franz Müller: Heterotopic ossifications. In: Bernhard Weigel, Michael Nerlich (eds.): Praxisbuch Unfallchirurgie. Volume 2, Springer-Verlag, Berlin 2005, ISBN 3-540-41115-1 , Chapter 18.2.3, pp. 1086-1088.
- ↑ CP Rader, T. Barthel: Heterotopic ossifications after hip TEP implantation . In: Klaus M. Peters, Dietmar Pierre König (Ed.): Advanced training in Osteology 1 . Springer, Heidelberg 2006, ISBN 3-7985-1601-4 , p. 92-99 .
- ^ Bernhard Weigel: Heterotopic ossifications. In: Bernhard Weigel, Michael Nerlich (eds.): Praxisbuch Unfallchirurgie. Volume 2, Springer-Verlag, Berlin 2005, ISBN 3-540-41115-1 , Chapter 6.3.3, pp. 330-332.
- ↑ Keith Baldwin, Surena Namdari, Harish Hosalkar, David A. Spiegel, Mary Ann Keenan: What's new in Orthopedic Rehabilitation. In: Journal of Bone and Joint Surgery. Volume 94-A, Issue 22, November 21, 2012, pp. 2106-2111. doi: 10.2106 / JBJS.L.00948
- ↑ Michael Wannenmacher, Jürgen Debus, Frederik Wenz: Radiotherapy . Springer, 2006, ISBN 3-540-22812-8 , pp. 820-847 ( books.google.com ).
