title: Maximum temperatures of 89°C recorded during the mechanical preparation of 35 femoral heads for resurfacing.
abstract: OBJECTIVE
  We noticed that our instruments were often too hot to touch after preparing the femoral head for resurfacing, and questioned whether the heat generated could exceed temperatures known to cause osteonecrosis.
  
  
  METHODS
  Using an infra-red thermal imaging camera, we measured real-time femoral head temperatures during femoral head reaming in 35 patients undergoing resurfacing hip arthroplasty. 7 patients received an ASR, 8 received a Cormet, and 20 received a Birmingham resurfacing arthroplasty.
  
  
  RESULTS
  The maximum temperature recorded was 89°C. The temperature exceeded 47°C in 28 patients and 70°C in 11. The mean duration of most stages of head preparation was less than 1 min. The mean time exceeded 1 min only on peripheral head reaming of the ASR system. At temperatures lower than 47°C, only 2 femoral heads were exposed long enough to cause osteonecrosis. The highest mean maximum temperatures recorded were 54°C when the proximal femoral head was resected with an oscillating saw and 47°C during peripheral reaming with the crown drill. The modified new Birmingham resurfacing proximal femoral head reamer substantially reduced the maximum temperatures generated. Lavage reduced temperatures to a mean of 18°C.
  
  
  CONCLUSIONS
  11 patients were subjected to temperatures sufficient to cause osteonecrosis secondary to thermal insult, regardless of the duration of reaming. In 2 cases only, the length of reaming was long enough to induce damage at lower temperatures. Lavage and sharp instruments should reduce the risk of thermal insult during hip resurfacing.
authors: The Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK. richardbaker14@hotmail.com
authors: Richard
authors: R
authors: Baker
authors: Michael
authors: M
authors: Whitehouse
authors: Michael
authors: M
authors: Kilshaw
authors: Morreica
authors: M
authors: Pabbruwe
authors: Robert
authors: R
authors: Spencer
authors: Ashley
authors: A
authors: Blom
authors: Gordon
authors: G
authors: Bannister
mesh_terms: D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D001843:Bone Cements / Q000009:adverse effects; D005260:Female; D005270:Femur Head; D005271:Femur Head Necrosis / Q000209:etiology; D006622:Hip Prosthesis; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008297:Male
chemical_list: D001843:Bone Cements