Question: Do complication rates differ between daily and weekly
pin-site care in patients in whom an external fixator has been used to
stabilize a high tibial osteotomy in the treatment of gonarthrosis of the
knee?
Design: Randomized (unclear allocation concealment), unblinded,
controlled trial with follow-up to pin removal.
Setting: A university hospital in Lund, Sweden.
Patients: 50 patients (mean age, 54 y, 62% men) undergoing surgery
for gonarthrosis by the hemicallotasis technique with use of 2
hydroxyapatite-coated pins in the metaphyseal bone and 2 standard conical pins
in the diaphyseal bone. The Orthofix T-garche was used for external fixation.
Complete follow-up was achieved for all patients.
Intervention: Patients were allocated to weekly (n = 23) or daily (n
= 27) pin-site care. Pin-site care involved cleaning with 0.9% NaCl solution
and placing a sterile compress on each pin pair, and fixing the compress with
a soft dressing. Sterile material and clean gloves were used in the outpatient
clinic and by district nurses in the patients' homes. All patients received 3
doses of intravenous antibiotic prophylaxis with cloxacillin (2 g) and then
oral flucloxacillin (1 g, 3 times daily for 14 days). Acetaminophen and
dextropropoxyphene or tramadol were used for analgesia.
Main outcome measures: Infection rate and severity were assessed
with use of the Checketts-Otterburns classification system (grades I to III =
minor infection; grades IV to VI = major infection); bacterial cultures of
crusted material obtained from the pin sites were done at 1, 6, and 10 weeks
and at the time of pin removal; and pain was assessed with a 10-point visual
analog scale (0 = no pain; 10 = extreme pain).
Main results: No difference existed between the weekly and daily
pin-site care groups in terms of frequency or severity of infection. The mean
rates of grade-I or II infection were 14% and 4%, respectively, for weekly
care and 10% and 3%, respectively, for daily care. The rates at 10 weeks and
at the time of extraction are shown in the Table. No grade-III through
grade-VI infections occurred. The number of positive cultures was greater in
the weekly than in the daily pin-site care group at 6 weeks (36 vs 24; p =
0.02), but these numbers did not differ at any other time point. The groups
did not differ with regard to
pain.
Conclusions: Pin-site complications following surgery for
gonarthrosis were no more frequent with weekly than with daily pin-site care
in patients with an external fixator.
Pin-site infections are the most common and feared complication associated
with the use of external fixators. However, because there is a lack of
evidence to guide the management of the local skin wound at the pin site, the
techniques of pin care remain in the realm of anecdote and personal
preference1. This
study by W-Dahl and colleagues, which compares 2 different time-intervals for
pin care, provides valuable information by showing that there are no easily
measurable differences between daily and weekly pin-site care. A previous
trial has shown that no pin-site care at all leads to better results than
pin-site care with either of 2 cleansing
solutions2.
Together, these studies support a minimalist philosophy of pin care.
The development and severity of pin-site infections is probably associated
more with the mechanical integrity of the pin-bone interface than with the
technique of caring for the pin
site3. Topical
antibiotics, antibacterial pin coatings, and a variety of pin-care techniques
do not prevent clinically important pin-track infections. However, improving
mechanics and preventing pin-loosening with the use of bigger pins, tapered
pins, a greater number of pins, and, most recently, hydroxyapatite-coated pins
have all been shown to decrease the rate of pin-site
infection3.
The patients in this study underwent placement of tibial fixators, a
relatively stable frame-bone construct, for hemicallotasis during high tibial
osteotomy. The favorable mechanics at the pin-bone interface suggest a
relatively low risk for pin problems as shown by the absence of severe
infections in either group. Whether the results of this study could be
generalized to a more mechanically demanding external fixator-bone construct
is uncertain. It seems unlikely that any cleansing strategy could prevent
infections around mechanically loose pins; however, this study showed that,
with a mechanically stable pinbone interface, the pins performed well
regardless of cleansing techniques and frequency.
Temple J, Santy J. Pin site care
for preventing infections associated with external bone fixators and pins.
Cochrane Database Syst Rev.2004;1:
CD004551.1CD004551
2004
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