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Which of the following processes relies on an exopolysaccharide glycocalyx?
Metastatic bone disease
Endochondral bone formation
Intramembranous bone formation
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Exopolysaccharide glycocalyx allows bacteria to adhere to orthopaedic implants and elude antimicrobial therapies through the creation of biofilms.
Biofilms are defined as a structured community of bacterial cells enclosed in a self-produced polymeric matrix and adherent to an inert or living surface. Biofilm production usually occurs within 4 weeks, and is extraordinarily hard to eradicate with antibiotic therapy alone. In the setting of a chronic infection of an orthopaedic implant (>4 weeks), explantation of the implant followed by antimicrobial therapy is the most reliable method of curing the infection.
Nguyen et al. reviewed 21 patients who underwent revision arthroplasty with negative intraoperative cultures. After standard cultures were obtained (all negative), the implants underwent an ultrasound protocol to theoretically disrupt the biofilm. 1 of the 21 implants grew coag-negative Staph after the bath.
Fux et al. reviewed biofilms with respect to orthopaedic and non-orthopaedic conditions. They discussed how aspirations are often falsely negative possibly because the microorganisms persist only within a biofilm on the synovia but not in planktonic form.
Illustration A and the video provided show the process of biofilm formation.
Answer 1: Osteoclast differentiation relies on the RANK-RANKL signaling pathway.
Answer 3: Osteolytic bone lesions are also caused by the RANK-RANKL pathway.
Answer 4: Endochondral bone formation occurs when osteoblasts lay down bone on a cartilaginous framework. Exopolysaccharide glycocalyx does not play a role in this.
Answer 5: Intramembranous bone formation does not involve exopolysaccharide glycocalyx.
Nguyen LL, Nelson CL, Saccente M, Smeltzer MS, Wassell DL, McLaren SG
Clin. Orthop. Relat. Res.. 2002 Oct;(403):29-37. PMID: 12360004 (Link to Abstract)
Fux CA, Stoodley P, Hall-Stoodley L, Costerton JW.
Expert Rev Anti Infect Ther. 2003 Dec;1(4):667-83. PMID: 15482163 (Link to Abstract)
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After open reduction and internal fixation of long bone fractures, at what time period should C-reactive protein start to decrease?
C-reactive protein (CRP) should peak by 48 hours after surgical fixation of bony orthopedic injuries, and decrease thereafter. This is important to recognize, as an increasing CRP after 48 hours is predictive for postoperative infection, and is more predictive in the first postoperative week than local erythema, persistent serous drainage, and increasing serial ESR.
The first referenced study by Waleczek et al noted that CRP was the earliest sign of developing infection and that clinical diagnosis, ultrasound, and WBC counts all lagged significantly behind CRP as a diagnostic tool. They report that latency to the clinical diagnosis based on clinical signs, ultrasound, WBC in blood and wound drainage was up to 14 days, while there was no patient with CRP increasing after day 2 without an infection.
The second referenced article by de Zwart et al noted an increased sensitivity and specificity of CRP as compared to ESR in the scenario of a clinically suspected infection. They advocate for determination of two CRP-levels with a short interval to screen for a clinically suspected infection.
Furthermore, Mok et al found that CRP showed an exponential decrease with a half-life of 2.6 days in postoperative spine patients. They found that CRP is a reliable test in the early postoperative period compared with ESR.
Waleczek H, Kozianka J, Everts H.
Chirurg. 1991 Dec;62(12):866-70. PMID: 1773631 (Link to Abstract)
de Zwart PM, Müller JE, Ebert B.
Aktuelle Traumatol. 1994 Oct;24(6):228-31. PMID: 7801820 (Link to Abstract)
Mok JM, Pekmezci M, Piper SL, Boyd E, Berven SH, Burch S, Deviren V, Tay B, Hu SS
Spine. 2008 Feb;33(4):415-21. PMID: 18277874 (Link to Abstract)
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Which of the following is the most sensitive parameter to detect the increased inflammatory response seen with both postoperative infection and the use of instrumentation in spinal surgery?
Erythrocyte sedimentation rate
The most sensitive parameter to detect inflammation elicited by implants and infection is the C-reactive protein (CRP).
CRP is an acute phase reactant that increases sharply immediately after surgery within 6 hours after tissue damage. CRP then peaks 2-3 days later and returns to normal levels 5-21 days after the inciting event. In contrast, ESR reaches its peak on days 4-11, then remains elevated for a prolonged period of time.
Takahashi et al performed a Level 3 study of patients who had undergone spinal surgery with and without instrumentation, with a primary outcome of infection. They concluded that renewed elevation of C-reactive protein, white blood cell count, and body temperature after postoperative days 4 to 7 may be a key indicator of postoperative infection.
Takahashi J, Ebara S, Kamimura M, Kinoshita T, Itoh H, Yuzawa Y, Sheena Y, Takaoka K
Spine. 2001 Aug;26(15):1698-704. PMID: 11474357 (Link to Abstract)
Average 3.0 of 20 Ratings
HPI - patient was reffered by the general physician patient had come to the physcian with c/o of cough since a week and a chest xray was done and this is what they saw. she was reffered to the cardiothoracic surgeon but then patient did not follow up
removal of wires or leave it alone