Chronic osteomyelitis is a persistent bone infection that can arise from various causes, including untreated acute osteomyelitis, tuberculosis, or fungal infections, and remains more prevalent in developing countries. Diagnosis typically involves clinical symptoms and radiological examinations, with treatment primarily surgical, aiming to remove dead bone and infected tissue. Common complications include acute flare-ups of infection, growth abnormalities, and, in rare cases, malignancy from chronic sinuses.

1. CHRONIC OSTEOMYELITIS
Dr.Akshay (PT)

2. Introduction
• The term ‘chronic osteomyelitis’ is used for chronic
pyogenic osteomyelitis.
• Although, its incidence is on the decline in developed
countries, it continues to be an important problem in
developing countries.
• The other causes of chronic osteomyelitis are
tuberculosis, fungal infections etc.
There are three types of chronic osteomyelitis:
a) Chronic osteomyelitis secondary to acute osteomyelitis.
b) Garre’s osteomyelitis.
c) Brodie’s abscess.

3. PATHOLOGY
• Acute osteomyelitis commonly leads to chronic osteomyelitis
because of one or more of the following reasons:
a) Delayed and inadequate treatment: This is the
commonest cause for the persistence of an osteomyelitis.
• Delay causes spread of pus within the medullary cavity and
subperiosteally.
• This results in the death of a part of the bone (sequestrum
formation).
• Destruction of cancellous bone leads to the formation of
cavities within the bone. Such ‘non-collapsing’ bone cavities
and sequestra are responsible for persistent infection.

4. b) Type and virulence of organism:
• Sometimes, despite early, adequate treatment of
acute osteomyelitis, the body’s defense
mechanism may not be able to control the
damaging influence of a highly virulent
organism, and the infection persists.

5. c) Reduced host resistance:
• Malnutrition compromises the body’s defense
mechanisms, thus letting the infection persist.

6. Pathology
• Sequestrum is a piece of dead bone, surrounded by
infected granulation tissue trying to ‘eat’ the
sequestrum away. It appears pale and has a smooth
inner and rough outer surface because the latter is
being constantly eroded by the surrounding
granulation tissue.
• Involucrum is the dense sclerotic bone overlying a
sequestrum. There may be some holes in the
involucrum for pus to drain out. These holes are called
cloacae. The bony cavities are lined by infected
granulation tissue.

7. DIAGNOSIS
• Diagnosis is suspected clinically but can be
confirmed radiologically by its characteristic
features.
• The disease begins in childhood but may present
later.
• The lower-end of the femur is the commonest
site.

8. Presenting complaints
• A chronic discharging sinus is the commonest presenting
symptom.
• The onset of sinus may be traced back to an episode of acute
osteomyelitis during childhood.
• Often sinuses heal for short periods, only to reappear with each
acute exacerbation.
• Quality of discharge varies from seropurulent to thick pus.
• There may be a history of extrusion of small bone fragments from
the sinus.
• Pain is usually minimal but may become aggravated during acute
exacerbations.
• Generalised symptoms of infection such as fever etc., are present
only during acute exacerbations.

9. Examination:
• Some of the salient features observed on examination
are as follows:
• Chronic discharging sinus: This is a characteristic
feature of chronic infection. A sinus fixed to the
underlying bone indicates that infection is coming from
the bone.
• There may be sprouting granulation tissue at its
opening, indicating a sequestrum within the bone.
• The sequestrum may be visible at the mouth of the sinus
itself. The sinus may be surrounded by healed puckered
scars, indicating previous healed sinuses.

10. Examination :
• Thickened, irregular bone: This can be
appreciated on comparing the girth of the affected
bone with that of the bone on the normal side
• Tenderness on deep palpation, usually mild,
is present in some cases
• Adjacent joint may be stiff, either due to
excessive scarring in the soft tissues around the
joint, or because of associated arthritis of the
joint.

11. INVESTIGATIONS
Radiological examination: The following are some of the
salient radiological features seen in chronic osteomyelitis:
• Thickening and irregularity of the cortices
• Patchy sclerosis
• Bone cavity: This is seen as an area of rarefaction surrounded
by sclerosis
• Sequestrum: This appears denser than the surrounding
normal bone because the decalcification which occurs in
normal bone, does not occur in dead bone. Granulation tissue
surrounding the sequestrum gives rise to a radiolucent zone
around it. A sequestrum may be visible in soft tissues.
• Involucrum and cloacae may be visible.

12. INVESTIGATIONS
Sinogram: In this test, a sterile thin catheter is introduced
into the sinus as far as it can go. Then, a radio-opaque dye
is injected, and X-rays taken. The radio-opaque dye travels
to the root of the infection, and thus helps localise it better.
It is indicated in situations where one cannot tell on X-rays
where the pus may be coming from.
CT scan and MRI: are sometimes indicated in patients
where diagnosis is in doubt. CT scan is of particular use in
better defining the cavities and sequestra, which sometimes
cannot be seen on routine X-rays. Exact localisation of a
cavity or sequestrum has bearing on surgical treatment.

13. INVESTIGATIONS
Blood: A blood examination is usually of no help. ESR
may be normal or mildly elevated. Total blood counts
may be normal, may be increased during acute
exacerbation only.
• Pus: Pus culture may grow the causative organism.
This should be taken from depth of the sinus after
proper cleaning of the skin. If an organism is grown, it
may be useful in controlling the acute on chronic stage
of the disease. It may also help in selecting the pre-
operative antibiotics as and when operation is
performed.

14. DIFFERENTIAL DIAGNOSIS
a) Tubercular osteomyelitis: The discharge is often thin and
watery. A tubercular sinus may show its characteristic features like
undermined margins and bluish surrounding skin. Tubercular
osteomyelitis is often multifocal. Patient may be suffering from or
may have suffered from pulmonary tuberculosis.
b) Soft tissue infection: A longstanding soft tissue infection with
a discharging sinus may mimic osteomyelitis. Absence of
thickening of underlying bone, and absence of sinus fixed to the
bone, may point towards the infection not coming from the bone.
Absence of any radiological changes in the bone would help
conform the diagnosis.
c) Ewing’s sarcoma: A child with Ewing’s sarcoma sometimes
presents with a rather sudden onset pain and swelling, mostly in
the diaphysis. Radiological appearance often resembles that of
osteomyelitis. A biopsy will settle the diagnosis.

15. TREATMENT
Principles of treatment: Treatment of chronic
osteomyelitis is primarily surgical. Antibiotics
are useful only during acute exacerbations and
during postoperative period. Aim of surgical
intervention is:
(i) removal of dead bone; (ii) elimination of dead
space and cavities; and (iii) removal of infected
granulation tissue and sinuses.

16. Operative procedures
Following are some of the operative procedures
commonly performed:
a) Sequestrectomy: This means removal of the
sequestrum. If it lies within the medullary cavity,
a window is made in the overlying involucrum
and the sequestrum removed. One must wait for
adequate involucrum formation before
performing sequestrectomy.

17. Operative procedures
b) Saucerisation: A bone cavity is a ‘non-collapsing
cavity’, so that there is always some pentup pus inside
it. This is responsible for the persistence of an infection.
In saucerisation, the cavity is converted into a ‘saucer’
by removing its wall. This allows free drainage of the
infected material.
c) Curettage: The wall of the cavity, lined by infected
granulation tissue, is curetted until the underlying
normal-looking bone is seen. The cavity is sometimes
obliterated by filling it with gentamycin impregnated
cement beads or local muscle flap.

18. Saucerisation

19. Operative procedures
d) Excision of an infected bone: In a case where the
affected bone can be excised en bloc without
compromising the functions of the limb, it is a good
method e.g., osteomyelitis of a part of the fibula. With
the availability of Ilizarov’s technique, an aggressive
approach, i.e., excising the infected bone segment and
building up the gap by transporting a segment of the
bone from adjacent part has shown good results .
e) Amputation: It may, very rarely, be preferred in a
case with a long standing discharging sinus, especially
if the sinus undergoes a malignant change.

21. Operative procedures
• In most cases, a combination of these procedures is
required.
• After surgery the wound is closed over a continuous
suction irrigation system.
• This system has an inlet tube going to the medullary
cavity, and an outlet tube bringing the irrigation fluid
out.
• A slow suction is applied to the outlet tube. The irrigation
fluid consists of suitable antibiotics and a detergent.
• The medullary canal is irrigated in this way for 4 to 7
days.

22. Continuous
suction
irrigation

23. COMPLICATIONS
1. An acute exacerbation or ‘flare up’ of the infection occurs commonly. It subsides
with a period of rest, and antibiotics, either broad-spectrum or based on the pus
culture and sensitivity report.
2. Growth abnormalities: Osteomyelitis may cause growth disturbances at the
adjacent growth plate, in one of the following ways:
• Shortening, when the growth plate is damaged.
• Lengthening because of increased vascularity of the growth plate due to the nearby
osteomyelitis.
• Deformities may appear if a part of the growth plate is damaged and the remaining
keeps growing.
3. Pathological fracture may occur through a weakened area of the bone. Treatment
is by conservative methods.
4. Joint stiffness may occur because of scarring of soft tissues around the joint or due
to the joint gettting secondarily involved.
5. Sinus tract malignancy is a rare complication. It occurs many years after the onset
of osteomyelitis. It is usually a squamous cell carcinoma. The patient may need
amputation.
6. Amyloidosis: As with all other long standing suppurations, this is a late
complication of osteomyelitis.

24. PROGNOSIS
To cure a bone infection is very difficult. Operative
intervention may be useful if there is an obvious
factor responsible for the persistence of the
infection e.g., sequestrum, cavity etc.

25. THANK YOU . . .