Question: In patients having primary total knee arthroplasty (TKA)
in a bloodless field with use of a pneumatic tourniquet, are there differences
with respect to skin injuries (blisters) among an elastic stockinette, cast
padding, and no protective material?
Design: Randomized (unclear allocation concealment), unblinded, and
controlled trial with follow-up to removal of the tourniquet.
Setting: A hospital in Stockholm, Sweden.
Patients: 94 patients having primary TKA for osteoarthritis or
rheumatoid arthritis were enrolled. 92 patients (mean age, 71 y; 65% women)
completed the study.
Intervention: Patients were allocated to a 2-layer elastic
stockinette (n = 33) or cast padding (n = 29) under the pneumatic tourniquet,
or to no protective material (n = 30). Patients received a 140-mm-wide conical
cuff or a 100-mm-wide cylindrical cuff at the discretion of the surgical
nurse, with recommended cuff pressures of 70 to 100 mm Hg (conical) and 100 to
150 mm Hg (cylindrical) above the patient's systolic blood pressure as
determined by the surgeon.
Main outcome measures: Presence of blisters, recorded by the nurse
inspecting the skin directly after removing the tourniquet at the completion
of surgery.
Main results: No patients who received the elastic stockinette had
blisters (Table). Fewer
patients who received cast padding had blisters than patients with no
protective material, but the difference did not reach significance
(Table).
Conclusion: In patients having primary total knee arthroplasty in a
bloodless field with use of a pneumatic tourniquet, an elastic stockinette
under the tourniquet prevented the development of blisters better than no
protective material.
The study by Olivecrona and colleagues confirms that protection underneath
pneumatic tourniquets during TKA is advantageous. The study was underpowered
to explore other variables related to the risk of skin breakdown, such as
diagnosis, gender, and body mass index. For example, patients with rheumatoid
arthritis have more fragile skin caused by disease-modifying medications that
alter collagen cross-linking; diabetes may be associated with compromised skin
vascularity, increasing the predisposition to skin ulceration; and body mass
index correlates with the thickness of the subcutaneous layer, which in turn
may have an effect on pressure distribution and skin breakdown.
The difference between patients with a higher compared with a lower rate of
blister formation may have been secondary to tourniquet time (112 vs 94 min,
respectively; p = 0.04). Tourniquets with wider cuffs produce lower readings
of blood pressure relative to narrow
cuffs1. However, in
this study, 8 of 41 patients with conical tourniquets (140 mm wide) had
blisters compared with 2 of 50 patients with cylindrical cuffs (100 mm
wide).
This study clearly identifies that protection (padding or stockinette) is
better than no protection under the tourniquet. From a resource utilization
perspective, protection adds little cost to the procedure, and it is an
effective means of averting skin breakdown and postoperative wound care. A
more in-depth study to identify the factors that would predispose patients
having a TKA to skin breakdown would be very helpful.
Moore MR, Garfin SR, Hargens AR. Wide tourniquets eliminate blood
flow at low inflation pressures. J Hand Surg [Am].1987;12:
1006-11.121006
1987
[PubMed]