3. STRUCTURE COMMENT
STRUCTURAL BONE TYPES
Cortical (compact) • Strong, dense bone, makes up 80% of the skeleton
• Composed of multiple osteons (haversians system) with
intervening interstitial lamellae
• Osteons are made up of concentric bone lamellae with a central
canal (haversian canal) containing osteoblasts (new bone
formation) and an arteriole supplying the osteon. Lamellae are
connected by canaliculi. Cement lines mark outer limit of osteon
(bone resorption ended)
• Volkmann’s canals: radially oriented, have arteriole, and connect
adjacent osteons
• Thick chortical bone is found in the diaphysis of long bones
Cancellous (spongy/trabecular)
• Crossed lattice structure, makes up 20% of the skeleton
• High bone turnover rate. Bone is resorbed by osteoclasts in
Howship’s lacunae and formed on the opposite side of the
trabeculae by osteoblasts
• Osteoporosis is common in cancellous bone, making it susceptible
to fractures (e.g., vertebral bodies, femoral neck, distal radius,
tibial plateau)
• Commonly found in the metaphysis and epiphysis of long bones
Cortical and Cancellous Bone
Thompson JC. Netter's Concise Orthopaedic Anatomy. 2nd ed. 2010. Saunders Elsevier.
4. CORTICAL BONE
• Strong, dense bone,
makes up 80% of the
skeleton
• Multiple osteons
(haversians system)
Haversian canal
containing osteoblasts
An arteriole supplying
the osteon
• Volkmann’s canals
• Diaphysis of long bones
5. ETIOLOGY
• Osteomyelitis : let just say it is an infection to the
bone
• The mere presence of bacteria in bone, whether
from bacteremia or from direct inoculation, is
insufficient to produce osteomyelitis
• Morrissy and Haynes have shown the relationship
of trauma to osteomyelitis
→ Also : illness, malnutrition, and inadequacy of
the immune system
6. Focus of infection
OSTEOMYELITIS
Picture (left): Salter RB.
Textbook of Disorders and
Injuries of the
Musculoskeletal System.
3rd ed. LWW. p:210.
+ underlie condition
eg.: trauma, illness, etc
7. ETIOLOGY
• The peculiarity of an abscess in bone is that it is contained within a
firm structure with little chance of tissue expansion
• As infection progress :
– Increase of puruluent material in the haversian system and
Volkmann canals
– Periosteum elevation from the surface of bone
– Pus in the medullary cavity + pus in the subperiosteal space →
necrosis of cortical bone (sequestrum)
• Sequestrum :
– Bacteria harbor
– Antibiotics and inflammatory cells cannot adequately access this
avascular area, resulting in failure of medical treatment of
osteomyelitis
8. ETIOLOGY
Risk of Infection Evaluation
Patient-
Dependent
Nutrition
Immuno-
logical
Status
Infection
at a
remote
site
Surgeon-Dependent
Prophy-
lactic AB
Skin &
wound
care
Operating
environ-
ment
Surgical
technique
Treatment
of
impending
infections
9. PATIENT-DEPENDENT
Nutritional Status
• Basal energy requirements of a traumatized or infected
patient increase from 30% to 55% of normal
• Fever of just 1°F above normal increases the body's
metabolic rate 13%
• Nutritional status can be determined preoperatively by :
1) Anthropometric measurements (BH, BW, triceps skin
fold thickness, & arm muscle circumference)
2) Measurement of serum proteins or cell types
(lymphocytes)
3) Antibody reaction to certain antigens in skin testing
10. PATIENT-DEPENDENT
Immunological Status
• The body's main defense mechanisms are :
1. Neutrophil response
2. Humoral immunity
3. Cell-mediated immunity
4. Reticuloendothelial cells
• A deficiency in production or function of any of these
predisposes the host to infection by specific groups of
opportunistic pathogens
• Deficiencies in the immune system :
– Acquired, or
– Congenital abnormalities
12. ISSUES TO REMEMBER
• There are bacteria on the skin (normal flora)
• Wound contamination exists anytime the skin
barrier is broken
• The skin (and the hair) can be sterilized, but can
never be disinfected completely
• It is almost impossible to sterilize the hair follicles
and sebaceous glands
• Hand washing
• Hair removal
SURGEON-DEPENDENT
Skin Preparation
13. Skin and Hair Issues
• The number of bacteria present can be reduced
markedly before surgery
• The hair follicles and sebaceous glands:
Normal place for bacteria to reside and reproduce
Oily environment → skin preparations can't
penetrate
Disinfectants that penetrate the oily environment
are absorbed by the body and have potentially toxic
side effects (e.g, hexachlorophene → neurotoxic)
SURGEON-DEPENDENT
Skin Preparation
14. Hand Washing
• Most important for prevention of nosocomial infection
• Studies: hand scrubbing for 2 minutes is as effective as
traditional hand scrubbing for 5 minutes
• The optimal duration?
SURGEON-DEPENDENT
Skin Preparation
Characteristics of Common Antiseptic Agents
Agent On Gram (+) On Gram (-) On Viruses (*)
On M.
Tuberculosis
On Fungi
Alcohol +++ +++ ++ +++ +++
Clorhexidine +++ ++ ++ ++ ++
Iodophors +++ +++ ++ ++ ++
Triclosan ++ ++ ++ + -
From Wong KC, Leung KS: Current concepts review: transmission and prevention of occupational infections in orthopaedic surgeons, J Bone Joint Surg 86A:1065, 2004.
* All agents are effective against enveloped viruses, which include hepatitis B virus, hepatitis C virus, human immunodeficiency virus, and coronavirus. +++, excellent; ++,
good; +, fair; −, poora
15. Hair Removal
• Hair removal at the operative site is not
recommended unless done in the operating room
• Shaving the operative site the night before surgery
can cause local trauma that produces a favorable
environment for bacterial reproduction
Surgical Gloves
• At a minimum, surgical gloves should be changed
every 2 hours
SURGEON-DEPENDENT
Skin Preparation
16. Airborne bacteria:
• Another source of wound contamination in the
operating room
• Usually are gram-positive and originate almost
exclusively from humans in the operating room
• May be reduced by at least 80% with laminar-
airflow systems and even more with personnel-
isolator systems
• UV light also has been shown to decrease the
incidence of wound infection
SURGEON-DEPENDENT
Operating Room Environment
17. SURGEON-DEPENDENT
Prophylactic Antibiotic Therapy
GOLDEN PERIOD :
The first 6 hours
FIRST 2 HOURS
The host defense
mechanism works to
decrease the overall
number of bacteria
NEXT 4 HOURS
The number of bacteria
remains fairly constant,
with the bacteria that
are multiplying and the
bacteria that are being
killed by the host
defenses being about
equal
> 6 HOURS
The bacteria
multiply
exponentially
The administration of prophylactic antibiotics
EXPANDS the golden period
In the first 24 hours, infection depends on the NUMBER of bacteria present
18. • Prophylactic antibiotic:
– Safe
– BACTERICIDAL
– Effective
• Major source of orthopaedic infection → the skin (S.
aureus, S. epidermidis)
• In the US, 1st-generation cephalosporins have been
favored for many reasons (nontoxic, inexpensive, and
effective)
SURGEON-DEPENDENT
Prophylactic Antibiotic Therapy
19. • Ideally → immediately before surgery
– ≤ 2 hours before incision
– Ideally 30 minutes before skin incision
• A maximal dose should be given
• Can be repeated :
– Every 4 hours intraoperatively, or
– Whenever the blood loss exceeds 1000 to 1500
mL
SURGEON-DEPENDENT
Prophylactic Antibiotic Therapy
20. THINGS YOU SHOULD KNOW
• AB coverage > 72 hours
– Little is gained
– The possibility of side effects is increased
(thrombophlebitis, allergic reactions, superinfections,
or drug fever)
• Namias et al. : AB coverage for > 4 days led to increased
bacteremia and IV line infections in patients in ICU
• Evidence now shows that 24 hours of AB administration
is just AS BENEFICIAL AS 48 to 72 hours
SURGEON-DEPENDENT
Prophylactic Antibiotic Therapy
21. ETIOLOGY
Foreign Material
• Implants, cement, allograft bone & connective
tissue, and synthetic suture material may
increase the risk of infection
• Experimental studies indicate that all
biomaterials commonly used for total joint
arthroplasty increase the incidence of S.
aureus infections
23. DIAGNOSIS
• May be obvious or obscure
• Signs and symptoms VARY with the rate and extent of
bone and joint involvement
• The classic triad :
– Fever,
– Swelling
– Tenderness or pain
• Pain probably is the most common symptom
• NO SINGLE TEST IS ABLE to serve as a definitive indicator
of the presence of musculoskeletal infection
24. DIAGNOSIS
Laboratory Studies
• Evaluation of :
– Complete blood count (CBC), including differential
and erythrocyte sedimentation rate (ESR)
– C-reactive protein (CRP)
• The WBC count is an unreliable indicator of infection
and often is normal even when infection is present
• The differential shows increases in NEUTROPHILS in
acute infections
25. TIMETABLE
NOTES
INCREASE PEAK RETURN TO NORMAL
ESR After 48
hours
3-5 days
after
infection
Approximately 3
weeks after treatment
is begun
Elevate in infection, malignancy,
other diseases, etc.
Unreliable in :
1. Neonates
2. Sickle cell disease
3. Patients taking steroids
4. Symptoms have been
present for < 48 hours
CRP Within 6
hours of
infection
2 days after
infection
Within 1 week after
adequate treatment
has begun
DIAGNOSIS
Laboratory Studies
28. TREATMENT
The principles of treatment are:
1) To provide analgesia and general supportive measures
2) To rest the affected part
3) To identify the infecting organism and administer
effective antibiotic treatment or chemotherapy
4) To release pus as soon as it is detected
5) To stabilize the bone if it has fractured
6) To eradicate avascular and necrotic tissue
7) To restore continuity if there is a gap in the bone
8) To maintain soft-tissue and skin cover
Editor's Notes
Formidable : berat, hebat, memerlukan usaha besar untuk mengatasi
