The metabolic response of trauma may mimic infection and the reliability of serological parameters for diagnosing infection may be questionable. We prospectively assessed the changes in the acute inflammatory markers, febrile response and the immune profiles of 101 patients following primary hip arthroplasty and their association with infection. Method: The clinical outcome of 101 patients was monitored. Serological analysis was performed pre-operatively and on the second and 8th post-operative day as well as in an out patient clinic 6 weeks following surgery. The serological markers included total white blood cell count along with T and B lymphocyte function. Levels of CD4, CD8 and CD56 were analysed for T helper, T Cytotoxic cell and Natural Killer cell activity. Inflammatory makers included plasma viscosity and CRP. Serological titres of Staph. Aureus and Staph. Epidermis were performed preoperatively and on day 8 and week 6 following surgery. Results: post-operative complications included 19 UTI, 11 chest infections and three URTI and six a confirmed deep vein thrombosis. Twenty patients had elevated ASO titres and 19 patients had raised Staph. Epidermis titres. Statistical comparison of WBC, Plasma viscosity, temperature profiles and T helper, T cytotoxic cell and NK cell assays is not different between patients with and without systemic infection or raised titres of Staph. Aureus or Staph. Epidermis. Conclusion: The acute phase responses following surgery and metabolic response to trauma obscures the changes seen in infective complications up to six weeks post-operatively. Their use in diagnosing infection appears unjustified.

The metabolic response of trauma may mimic infection and the reliability of serological parameters for diagnosing infection may be questionable. We prospectively assessed the changes in the acute inflammatory markers, febrile response and the immune profiles cytokine activation and collagen markers of 101 patients following primary hip arthroplasty and their association with infection.

Method: The clinical outcome of 101 patients was monitored. Serological analysis was performed pre-operatively and on the second and 8th post-operative day as well as in an out patient clinic 6 weeks following surgery. The serological markers included total white blood cell count along with T and B lymphocyte function. Levels of CD4, CD8 and CD56 were analysed for T helper, T Cytotoxic cell and Natural Killer cell activity. Inflammatory makers included plasma viscosity and CRP. Cytokine assays included IL-1, IL-6, IL-10 and TNF. Collagen markers included P1CP and P1NP as markers of Type I and Type III collagen synthesis. Serological titers of Staph. Aureus and Staph. Epidermis were performed pre-operatively and on day 8 and week 6 following surgery.

Results: Post-operative complications included 19 UTI, 11 chest infections and three URTI and six a confirmed deep vein thrombosis. Wound complications included 10 patients with wound erythema and 4 patients had pus discharge. 20 patients had elevated ASO titers and 19 patients had raised Staph. Epidermis titers.

Statistical comparison of WBC, Plasma viscosity, temperature profiles and T helper,

T cytotoxic cell and NK cell assays is not different between patients with and without systemic infection or raised titres of Staph. Aureus or Staph. Epidermis. Collagen markers were significantly higher in wound complications.

Conclusion: The acute phase responses following surgery and metabolic response to trauma obscures the changes seen in infective complications up to six weeks post-operatively. The use of serological parameters that are components of the acute phase response of surgery does not allow differentiation of infection from normal physiological changes.

Blood transfusion is associated with an increased incidence of post-operative nosocomial infections following surgery. In a prospective study we evaluated the association of blood transfusion and the changes in the immune status with the incidence of infection in the post-operative period following primary hip arthroplasty and subsequently for two years following surgery

Method: Prospective analysis of 100 patients undergoing primary total hip replacement. 25 patients received predonated autologus blood transfusions, 26 received SAGM whole blood, 23 received leukocyte depleted blood and 26 did not require a transfusion.

T-helper cell, cytotoxic T cell and NK cell activity was recorded using a Beckton Dickson flow cytometer and assays of Plasma viscosity, CRP, Staph. Epidermis and ASO titres were analysed. All infections were recorded for 2 years following surgery.

Results: he incidence of confirmed or suspected nosocomial infections following hip replacement was the same in non transfused patients as those receiving predonated autologus blood (19%). The incidence of nosocomial infection in patients receiving leukocyte depleted blood was 32% and 42% in those receiving a SAGM blood transfusion. ASO titres were raised in 16.9% of the patients on day 8 following surgery and Staph. Epidermis assays were raised in 20.2% of the patients however the frequency was unrelated to the type of blood transfusion.

The incidence of nosocomial infections was reflected by a greater reduction in NK activity and CD4: CD8 ratio following surgery in patients receiving SAGM blood transfusion.

Conclusion: Homologus blood transfusion may produce an immune compromise in patients, which is still detectable at 6 weeks following surgery. This is clinically reflected by a higher incidence of systemic infections in the postoperative period.

Homologus blood should be used judiciously in joint arthroplasty with a preference to either leukocyte depleted blood or predonated autologus blood.