A comparison of short term radiological alignment outcomes of the patient specific and standard instrumentation for primary total knee arthroplasty: A systematic review and meta-analysis.

OBJECTIVE: The aim of this study was to review the radiological alignment outcomes of patient Specific (PS) cutting blocks and Standard Instrumentation in Primary Total Knee Arthroplasty. METHODS: We hypothesized that the use of PS techniques would significantly improve sagittal, coronal and rotational alignment of the prosthesis on short term. We performed a systematic review and a meta-analysis including all the randomised controlled trials (RCT) using PS and standard (ST) total knee arthroplasty to date. RESULTS: A total of 538 PS TKA and 549 ST TKA were included in the study. Statistical analysis of the outliers for femoral component sagittal, coronal and rotational positioning, tibial component sagittal and coronal positioning and the overall mechanical axis were assessed. We found that there was no significant benefit from using PS instrumentation in primary knee arthroplasty to aid in the positioning of either the tibial or femoral components. Furthermore sagittal plane tibial component positioning was worse in the PS than the traditional ST group. CONCLUSION: Our results suggest that at present PS instrumentation is not superior to ST instrumentation in primary total knee arthroplasty. LEVEL OF EVIDENCE: Level 1, Systematic review of therapeutic studies.

Pyrexia following total knee replacement.

This study aims to determine the incidence and factors associated with pyrexia following total knee replacement (TKR). We performed a retrospective analysis of the temperature charts and histories of patients who underwent 170 TKRs. There was a statistically significant increase in mean temperature from pre-operation to post-operation, and this increase remained significant through to 5 days post surgery (p<0.0001). Sixty-two (36.5%) patients were pyrexial (>or=38 degrees C) at some point. Fourteen patients developed a clinical infection, but only four of these were pyrexial. There was no association between pyrexia and infection, allogenic blood transfusion, haemoglobin loss, use of urinary catheter, rheumatoid arthritis, anaesthetic type, and previous pyrexia following TKR. Pyrexia as a diagnostic test for the development of infection had a sensitivity of 0.286 (95% CI=0.084-0.581), specificity of 0.628 (95% CI=0.548-0.704) and positive predictive value of 0.065 (95% CI=0.018-0.157). Pyrexia in the first 5 days following TKR is usually a normal physiological response and should not cause undue concern about the presence of infection.