Fx Cadera

AUTHOR(S):
SPANGEHL, M. J., M.D., F.R.C.S.(C)‡;
YOUNGER, A. S. E., M.B., M.SC., F.R.C.S.(C)‡;
MASRI, B. A., M.D., F.R.C.S.(C)‡;
DUNCAN, C. P., M.B., M.SC., F.R.C.S.(C)‡,
VANCOUVER, BRITISH COLUMBIA, CANADA
An Instructional Course Lecture, The American
Academy of Orthopaedic Surgeons
J Bone Joint Surg [Am] 1997; 79-A; 1578-88
High rates of infection complicated the early
experience withtotal hip arthroplasty and, although
the rates have decreased substantially over the last
few decades, infection still is a source of considerable
morbidity. In the 1960s, Charnley reported a rate of
infection of 9.5 per cent (nineteen infections after 199
total hip arthroplasties)(5). More recently, authors
have reported that infection causes failure after 1 per
cent (seventy-one of 5081and twenty-seven of 2084)
to 2 per cent (ninety-four of 5500 and thirty-six of
1798) of primary total hip arthroplasties(6,13,20,22,37,38,
42,58,61)
, and the rate is higher after revision
procedures. Although these percentages are small, the
large number of hip arthroplasties performed each
year results in a major burden on the health-care
system(62). Infection following total hiparthroplasty
is costly to treat because of the subsequent need for
reoperation and the prolonged hospitalization often
required to eradicate the infection. In the United
States, the cost per year to treat the 3500 to 4000
infections following total hip arthroplasty is between
150 and 200 million dollars(62). Because of an aging
population that will need an increasing number of
arthroplasties,methods to prevent, diagnose, and treat
infection must be perfected in order to reduce the cost
of total hip arthroplasty to society.
Infection following total hip arthroplasty can
present a diagnostic challenge. No test is 100 per cent
sensitive and 100 per cent specific; thus, the
diagnosis of infection relies on the surgeon's
judgment of the clinical presentation, the findings on
physicalexamination, and the interpretation of the
results of previous investigations. The consequences
of misdiagnosis are considerable. Reimplantation of a
prosthesis into an infected tissue bed, without
appropriate débridement, is likely to result in
persistent infection(41). Numerous investigations are
available for the workup and diagnosis of failed total
hip replacements. These investigations,as well as an
algorithm to rule out the presence of infection as a
cause of failure, will be presented.
Clinical Presentation
A thorough history and physical examination are of

paramount importance in the diagnosis of infection.
Although a conclusive diagnosis can be made in
many instances, there are no data, to our knowledge,
with regard to the efficacy of clinical assessment
alone.Even when a conclusive diagnosis cannot be
established, a careful history and physical
examination can help to guide the appropriate
investigations.
Coventry(9), and later Fitzgerald et al.(21), described
what is perhaps the most common system for the
classification of infection after total hip arthroplasty.
This three-stage classification system is based on the
mode or timing of thepresentation of infection.
Type-I infections occur in the immediate
postoperative period. The patient usually is seen
during the first postoperative month, and the
diagnosis is evident on the basis of the medical
history and the physical examination. Systemic signs
of infection, such as fever, chills, and sweating, may
be present. Pain is usually continuous. On
examination, the wound may beerythematous,
swollen, fluctuant, and tender. Wound drainage, if
present, is usually purulent. Type-I infections are
caused by infected hematomas or superficial wound
infections spreading contiguously to the
periprosthetic space. The diagnostic challenge is to
determine whether or not a superficial infection has
penetrated deep to the fascia.
Type-II infections also are believed to originate...