Self-Warming Blanket Versus Forced-Air Warming in Primary Knee or Hip Replacement: A Randomized Controlled Non-Inferiority Study.

OBJECTIVE: After primary total knee/hip replacement (TKR or THR respectively) a prosthetic joint infection (PJI) could develop. Hypothermia could raise the risk of infection. Heating by forced-air can disrupt laminar airfl ow in the operation room (OR), potentially raising the risk of infection. We aimed to study non-inferiority of an active self-heating blanket (SHB) compared to a forced-air blanket (FAB) in preventing hypothermia. METHODS: A randomized controlled non-inferiority trial (N = 86 patients) was performed comparing a SHB versus a FAB in elective primary TKR/THR patients. Primary outcome was lowest measured temperature during surgery. Secondary outcomes were patients' core temperature before, during, and after surgery, thermal comfort visual analogue score (VAS) and complications during hospitalization. RESULTS: Lowest measured temperature was 35.9°C (± 0.6) in SHB and 36.1°C (± 0.5) in FAB group (p = 0.05). No signifi cant correlation was found with duration of surgery or temperature of the OR. No signifi cant difference in core temperature was found before surgery (SHB = 36.8°C [± 0.4], FAB = 36.8°C [± 0.5], p = 0.49), after induction of anaesthesia (SHB = 36.6°C [± 0.5], FAB = 36.7°C [± 0.5], p = 0.22) nor as a mean during surgery (SHB = 35.8°C [± 1.6], FAB = 36.0°C [± 1.3], p = 0.68). SHB patients were "colder" at the recovery bay, 35.8°C (± 0.6) compared to FAB patients, 36.1°C (± 0.5) (p = 0.04). Mean VAS thermal comfort was 53.3 (± 15.7) in SHB and 52.9 (± 12.3) in FAB patients. No difference in complication rate was found. CONCLUSIONS: In this study neither kind of the warming blanket prevented perioperative hypothermia. Although a difference of 0.2°C was found between both groups at the end of TKR/THR surgery, this is most probably not clinically relevant. Complication rate in both groups was the same.

Conversion from knee arthrodesis to arthroplasty: systematic review.

PURPOSE: Arthrodesis (AD) of the knee reduces pain and provides stability, but has severe functional and social limitations. There has been ample discussion on the value of a conversion of an AD to a total knee arthroplasty (TKA). The aim of this study was to perform a review and meta-analysis of the current literature on conversion of an AD to TKA and assess clinical outcome, complication rate, surgical technique and overall patient-related outcome measures. METHODS: PubMed, Embase, Web of Science, Cochrane, CENTRAL, CINAHL, Academic Search Premier, ScienceDirect and searching by hand for papers on conversion of AD of the knee to TKA. Two reviewers independently reviewed all titles and abstracts, and extracted the available data. Study eligibility criteria were: conversion of knee AD to TKA, five cases or more and non-oncology patients. Data consisted of study characteristics, patient demographics, clinical outcome and complications. Additionally, details on surgical technique were reviewed. RESULTS: Of the 866 unique references identified, six papers were included for further analyses, comprising a total of 123 knees with conversion of AD of the knee to TKA. Mean gain of knee flexion was 80 degrees and the mean HSS score improved with 20 points. A complicated postoperative course was found in 65 % of all cases. The most frequent complication was skin necrosis (25 %), followed by arthrofibrosis (13 %), infection (11 %) and revision (11 %). Major complications such as refusion, amputation and death occurred in less than 5 % of all cases. DISCUSSION: The majority of the papers consisted of small case series of moderate methodological quality, resulting in 123 included knees. Further series are necessary to draw definitive conclusions. CONCLUSIONS: This is the first systematic review and meta-analysis on conversion of a knee arthrodesis to TKA. Good clinical results can be expected after conversion, albeit at a high risk of postoperative complications.