The thermal effects of lavage on 57 ox femoral heads prepared for hip resurfacing arthroplasty.
OBJECTIVE
Previously, we have documented surface temperatures recorded by thermography great enough to cause osteonecrosis of the femoral head during hip resurfacing. We now performed an in vitro investigation with 3 questions: (1) whether water irrigation reduced bone surface temperature, (2) whether external bone temperatures were similar to core temperatures, and (3) whether blunting of the reamer affected temperature generation.


METHODS
Using an ox-bone model, 57 femoral heads were peripherally reamed. The surface temperatures of bone were measured using a thermal camera and internal bone temperatures were measured using 2 theromocouples. We measured the effects of cooling with water at room temperature and with ice-cooled water. Progressive blunting of reamers was assessed over the 57 experiments.


RESULTS
Mean and maximum temperatures generated during peripheral reaming were greater when no irrigation was used. Ice-cold saline protected femoral heads from thermal damage. External bone temperatures were much greater than internal temperatures, which were not sufficiently elevated to cause osteonecrosis regardless of lavage. Blunting of the reamer was not found to have a statistically significant effect in this study.


CONCLUSIONS
Cooling with ice-cooled water is recommended. Internal bone temperatures are not elevated despite the high surface temperatures reached during femoral head resurfacing.
The Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK.
Richard P
RP
Baker
Michael R
MR
Whitehouse
Angus
A
Maclean
Ashley W
AW
Blom
Gordon C
GC
Bannister
D000704:Analysis of Variance; D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods*; D001831:Body Temperature; D002417:Cattle; D003080:Cold Temperature; D004868:Equipment Failure; D005270:Femur Head / Q000601:surgery*; D006358:Hot Temperature / Q000009:adverse effects; D061646:Operative Time; D010020:Osteonecrosis / Q000209:etiology; D012965:Sodium Chloride; D013525:Surgical Instruments; D007507:Therapeutic Irrigation / Q000379:methods
D012965:Sodium Chloride