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There are 3 adhesive forces preventing dislodgement of debride or bacteria: capillary, molecular and electrostatic. Thus 3 types of forces to remove material are mechanical contact (eg. Brushing or scrubbing), inertial forces, and fluid dynamic pressure which is utilized by pulsatile lavage. Initial compression phase of the tissues under the impact of the pulse, followed by an interpulse decompression phase during the zero-pulse periods may loosen foreign material. Ejection of the material by the elastic recovery of the tissue during the zero-pulse period may assist in debridement.
Overall, pulsatile lavage has been shown to improve cement penetration in cancellous bone and increase mechanical strength at the cement–bone interface during in vitro studies. High-pressure pulsatile lavage should perhaps be reserved for severely contaminated wounds or for open injuries for which treatment will be delayed. Low-pressure irrigation might be useful if contamination is minimal or treatment is immediate. High-quality evidence is lacking regarding optimum lavage pressure in primary or revision TJA.
High-Volume Local Infiltration Analgesia
HVLIA has a reputation among surgeons as a simple, safe and convenient method that provides good analgesia without motor block of the lower limb.
There are potential benefits of infiltrating high volumes of local anaesthetics around the soft tissues of replaced hip and knee joints. The risk of systemic toxicity is minimized with diluted local anaesthetic solution, which also allows a high volume to be used. Some principal advantages include intra-operative administration of analgesic agents by the surgeon, thereby minimizing the need for additional invasive procedures. Analgesia may be prolonged up to 48 hours with long-acting local anaesthetics and the administration of supplemental doses via a wound catheter at regular intervals or continuous infusion.
Local infiltration analgesia uses a systematic infiltration of the periarticular soft tissues with a mixture of ropivacaine (a long-acting local anaesthetic with a superior cardiotoxicity profile in comparison to bupivacaine as well as for its intrinsic vasoconstrictor properties), ketorolac (an NSAID), and epinephrine (a vasoconstrictor).
The analgesic effect derived from the local anaesthetic mixture is due to the actions of the constituent drug (blockage of ion-gated Na channels on A and C-type nociceptive nerve endings). Local anaesthetics reduce the release of inflammatory mediators from neutrophils, reduce neutrophil adhesion to the endothelium, reduce formation of free oxygen radicals, and decrease oedema formation. In conjunction, NSAID’s reduce prostaglandin formation (Prostaglandins sensitize nociceptive fibers and lead to amplification and sustaining of pain).
The concept of HVLIA is a multimodal and multidisciplinary method of perioperative pain control, including patient education and rehabilitation support, as well as a potential reduction in opiate consumption, the achievement of early milestones, or a reduction in length of hospital stay.
What is the best skin preparation for the surgical site?
What is the optimum skin preparation agent? While Chlorhexidine gluconate (CHG) is the recommended agent for preventing intravenous catheter-related infections, there is currently no recommendation of one agent over another for prevention of Surgical site infections (SSI). When compared directly, results are conflicted as to whether CHG or povidone-iodine provides superior skin antisepsis and lowers the rate of SSI. To date, there are no prospective randomized studies comparing skin preps in patients undergoing total joint arthroplasty.
Alcohol is suggested to be an important element for skin antisepsis. Alcohol is used as an antiseptic because of its rapid antimicrobial action. It is suggested that whichever agent is chosen, that it be combined with alcohol. However, caution should be taken to allow time for adequate drying of alcohol-based products, given its flammable nature.
IN A NUTSHELL
ISAKOS NEWSLETTER 2015: Volume I 41