Relationship of the functional recovery after hip arthroplasty to the neuroendocrine and inflammatory responses

We studied the relationship between the neuroendocrine and inflammatory res ponses to hip arthroplasty and functional recovery in 102 patients undergoi ng elective arthroplasty for osteoarthritis. Blood samples were collected f or up to 7 days after surgery and analysed for concentrations of norepineph rine, epinephrine, cortisol, interleukin-6 and C-reactive protein. The prim ary outcome measures were milestones in hospital, times to walk 10 and 25 m , pain on discharge from hospital, and function I and 6 months after surger y. Walking distances in hospital were significantly delayed in patients wit h greater interleukin 6 and C-reactive protein concentrations, but few neur oendocrine measures had significant correlations with functional recovery i n hospital. Multivariate analysis showed that the interleukin 6 concentrati on on day I was the unique predictor of time to walk 10 and 25 m, and that the day 2 concentration of C-reactive protein was the unique predictor of p ain on discharge from hospital. No significant correlations were found betw een the inflammatory and neuroendocrine variables and recovery at I and 6 m onths. We conclude that the inflammatory response affects immediate functio nal recovery after hip arthroplasty.