|Annals of the MBC - vol. 4 - n' 3 - September 1991
POST- BURN HETEROTOPIC JOINT OSSIFICATIONS
First Orthopaedic Department, Teaching Hospital, Prague, Czechoslovakia
SUMMARY. In a 10-year period 3322 burn in-patients were treated. Out of this number 68 patients developed heterotopic joint ossifications - either symptomless or limiting joint movement extent in various degrees up to ankylosis. The present work attempts to determine: a) causes which could lead to heterotopic ossifications; b) clinical signs in the period, of presupposed heterotopic ossifications; c) methods for detecting heterotopic ossification maturity prior to planned resection.
Extensive bum trauma leaves almost 50% of patients with changes variously limiting joint movement. The causes of this condition are the following: scar contractures of the skin, tendons and articulare capsule, and heterotopic ossifications (H0) in the joint area. In soft tissue contractures limiting movement, the surgical treatment is clear. HO may be clinically symptomless or may limit joint movement extent in various degree up to ankylosis.
Patients and methods
In the years 1976-1986 3322 burn in-patients were treated at our Burns Centre. Out of this number 68 patients w ' ith HO development limiting joint movement were detected by systematic follow-up, including orthopaedic specialist participation, i.e. 2%, which is in agreement with other authors' data (1).
Age of Patients - Table I
Cause of Bum - Table II
Incidence in Indivual Joints - Table III
In the above population of handicapped patients the author attempted to.determine:
A. The evaluation of the acute phase thermal injury was based on case records of patients who subsequently developed HO with joint movement limitation.
The follow-up of these data was based
on references(2) dealing with HO development after brain injury accompanied by long-term
unconsciousness. Out of our population under study 7 patients were unconscious.
2. Septic fevers
Elevated temperature is a typical feature in thermal trauma: in this study patients with a septicaemia temperature curve lasting more than 3 weeks were followed. This criterion applied to 8 of the patients, in whom intra-articular ankylosis developed. The septic condition might threaten the joint with septic destruction and subsequent intraarticular ankylosis.
Second- and third-degree bums affecting the whole circumference of the limb may lead to the occurrence of the compartment syndro.me(3). Compressed soft tissues in the compartment area undergo necrotic changes which may turn into HO. Escharotomy decreases the danger of compartment syndrome sequelae. In patients treated from the beginning at a Bums Centre the intervention was always timely and of sufficient extent, and there were therefore not so many IjO cases as in patients brought from other surgical departments where escharotomy was not performed in time, or incorrectly.
4. Inborn and acquired joint alterations
Out of the population under study with HO in the joint area, 5 patients were found to have a history of severe trauma or malformation of the joint prior to the thermal injury. Although the number of such cases is not high, more attention should be paid to these joints during thermal injury treatment.
5. Individual tendency to HO development
Some case reports (5) mention the development of HO after every blunt trauma. answers were indefinite, the mean value according to the above scale being 1.2. References to the incidence of identical HO types in 2 burned brothers are also known (1). The key to this genetic predisposition may be in the HLA system distribution. A survey by means of HLA B27 showed the HLA distribution in normal population to be 7%, compared to 70% in HO patients. In our patients the response concerning the tendency to HO was never positive, but its possibility should also be considered in burn patients.
B. Radiological evidence of HO begins in the period from 9-18 weeks after the thermal injury. The possibility of HO development may manifest itself by the following facts:
1. Depth, extent and localization of burned skin area
2. Total immobility period of the patient
The mean time spent in hospital in our HO patients was 2 months. This confirms the reports of other authors (7, 8) that 2 months' total immobility predisposes to HO development: early mobilization, together with adequate kinesiotherapy,significantly reduces the occurrence of HO.
3. Itching in the site of the affected joint
Some case reports (6) mention itchin& in the site of HO development. Our patients were asked about itching over the site of periarticular HO, the evaluaton of its intensity being as follows: 0 = none, I = slight, 2 = moderate, 3 = severe.
4. Pain in the site of the affected joint
The intensity of pain in the area of the affected joint was tested by means of a subjective sensation scale analogous to that used for itching. The resulting mean value was 1.93. It can therefore be assumed that there may be pain in a joint with developing HO. Other causes of such pain must however also be taken into account, e.g. incipient infection.
5. Joint movement extent
In patients with HO in joint areas, the extent of joint movement varied from normal to total ankylosis. The movement extent was influenced by:
In many cases only the peroperative finding clarified the contribution of the above factors to the limited joint movement. The joint movement extent cannot therefore in most cases be correlated with X-ray findings. It is only the X-ray picture of joint destruction with intra-articular ankylosis and ankylosis due to massive bone bridging round the joint which corresponds to the clinical findings.
C. Extra-articular HO that limit joint movement are removed by their resection, and in joint devastation followed by intra-articular bone ankylosis by means of arthroplasty. Resection may be performed only in mature bone: after removal of immature bone the ossification process in the joint area recurs resulting again in limited movement.
1. Skin cover condition
The following facts were found, in correlation with the examinations mentioned below, in all patients studied:
2. Calcium and inorganic phosphorus levels
These were followed up in the period of developing HO as well as in their maturity, which was assessed by other methods. In all patients the level of these minerals in both periods studied was in the normal range, which provides evidence of the dystrophic origin of HO but also shows that it is not necessary to follow these data in HO in everyday practice.
3. Serum alkaline phosphatase level
The alkaline phosphatase isoenzyme is without doubt an osteoblastic activity index. The alkaline phosphatase level (in microcatals) was studied in children (4-15 years of age) and adult patients with HO. The assessment was peformed both in the period of HO development and of mature pyrophosphate activity in immature bone, i.e. the disappearance of ostcoblastic activity = maturity of HO. The scintigraphic investigation prior to planned HO resection is therefore highly recommended.
4. Enumeration and evaluation of possible methods for determining HO and their maturity
Alkaline Phosphatase Level (in microcatals) - Our investigations show that: a) the normal alkaline phosphatase not exclude the occurrence of ectopic ossification;level does b) periodical alkaline phosphatase follow-up may significantly contribute to determination of HO maturity.
Scintigraphic investigation: in cooperation with the Institute of Nuclear Medicine, HO osteoblastic activity assessment was performed by the scintigraphic method using short-time labelled pyrophosphate compounds. The investigations were carried out in the period of first-noticed subjective joint difficulties as well as in the period when according to X-ray pictures the bone was considered mature for resection. Comparison of the two examinations showed a marked decrease of the previously high level
RESUME Pendant une période de 10 ans 3322 patients brélés ont W hospitalisés. D'entre eux é8 ont présenté des ossifications hétérotopiques des articulations, ou sans symptémes ou avec une limitation de la capacité de mouvement des articulations plus ou moins grande, jusqu'd Pankylose. Cet article cherche A déterminer: a) les causes qui pourraient conduire aux ossifications hétérotopiques; b) les signes cliniques pendant la période des ossifications hétérotopiques présupposées; c) les méthodes pour dépister la maturité des ossifications hétérotopiques avant la résection planifiée.