Positive Intraoperative Cultures in Cup Revisions of THA: What Happens to the Stem?

BACKGROUND: Positive intraoperative cultures (PICs) are encountered in some patients undergoing revision of the acetabular cup after a previous THA. It is unknown whether PIC of the cup indicates whether the stem is infected as well and what happens to the stem during follow-up. QUESTIONS/PURPOSES: (1) What proportion of patients undergoing THA who undergo cup revision have PICs? (2) What is the survival of the stem during follow-up in cup revisions with PICs versus that of those with negative cultures? (3) Does antibiotic treatment of PIC of the cup prevent revision THA during follow-up? METHODS: In this retrospective, comparative multicenter study, five surgeons at four centers performed 338 acetabular cup revisions between January 2015 and December 2017. After evaluating the data, we excluded one patient because of an incomplete dataset and 77 patients because fewer than three intraoperative cultures were obtained during surgery, leaving 260 patients for analysis. Follow-up was 2 years. Patients were stratified into three cohorts: no PIC, one PIC, and two or more PICs. RESULTS: The proportion of patients with one or more PIC was 15% (39 of 260). A total of 8% (21 of 260) had one and 7% (18 of 260) had two or more PICs. Stem survival was lower in patients with two or more PICs, but stem revision for periprosthetic joint infection was similar between groups. Two-year survival, which was defined as freedom from revision for any cause or infection, was 97% (95% confidence interval 95% to 99%) in the group without PICs, 100% (95% CI 95% to 100%) in the group with one PIC, and 86% (95% CI 68% to 100%; p = 0.08) in the group with two or more PICs. None of the patients in the no PIC and one PIC groups were treated with antibiotics. In the two or more PICs cohort, 12 of 18 patients were treated. The stem survived in one of 12 patients treated with antibiotics versus two of six patients who were not treated with antibiotics. CONCLUSION: When treated with antibiotics, more than two PICs isolated during cup revision surgery do not have a major impact on survival of the stem during follow-up. A larger cohort of patients with PICs during cup revision might confirm these findings. LEVEL OF EVIDENCE: Level III, therapeutic study.

Preclinical model for lumbar interbody fusion in small ruminants: Rationale and guideline.

Lumbar interbody fusion (IF) is a common procedure to obtain fusion of the spine by replacement of the intervertebral disc with a cage. Optimization of spinal cages is ongoing to reduce complications such as a pseudoarthrosis and subsidence of the cage. IF animal models (primate, dog, pig, goat and sheep) remain important to assess implant effectivity. But currently the available literature is dispersed and not IF model specific. Therefore unwanted inconsistencies between studies occur that limit generalizability. Based on our experience, anatomical preparation and literature research, we present a rationale for species selection and a practical guide for the surgical procedure in the goat animal model. The translational Potential of this Article: Rigorous methodologic design is an important means to improve translational value and generalizability of large animal IF efficacy studies. This paper provides a rationale and practical guide for animal selection and surgical decision making that can help reduce unnecessary variation between models and improve methodologic rigor and documentation for future experiments.

Nuclear imaging does not have clear added value in patients with low a priori chance of periprosthetic joint infection. A retrospective single-center experience.

Background: A low-grade periprosthetic joint infection (PJI) may present without specific symptoms, and its diagnosis remains a challenge. Three-phase bone scintigraphy (TPBS) and white blood cell (WBC) scintigraphy are incorporated into recently introduced diagnostic criteria for PJI, but their exact value in diagnosing low-grade PJI in patients with nonspecific symptoms remains unclear. Methods: In this retrospective study, we evaluated patients with a prosthetic joint of the hip or knee who underwent TPBS and/or WBC scintigraphy between 2009 and 2016 because of nonspecific symptoms. We reviewed and calculated diagnostic accuracy of the TPBS and/or WBC scintigraphy to diagnose or exclude PJI. PJI was defined based on multiple cultures obtained during revision surgery. In patients who did not undergo revision surgery, PJI was ruled out by clinical follow-up of at least 2 years absent of clinical signs of infection based on MSIS 2011 criteria. Results: A total of 373 patients were evaluated, including 340 TPBSs and 142 WBC scintigraphies. Thirteen patients (3.5 %) were diagnosed with a PJI. TPBS sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were 71 %, 65 %, 8 % and 98 %, respectively. Thirty-five percent of TPBS showed increased uptake. Stratification for time intervals between the index arthroplasty and the onset of symptoms did not alter its diagnostic accuracy. WBC scintigraphy sensitivity, specificity, PPV and NPV were 30 %, 90 %, 25 % and 94 %, respectively. Conclusion: Nuclear imaging does not have clear added value in patients with low a priori chance of periprosthetic joint infection.

Factors to Consider When Assessing the Diagnostic Accuracy of Synovial Leukocyte Count in Periprosthetic Joint Infection.

Synovial white blood cell (WBC) count and the percentage of polymorphonuclear leucocytes (PMN%) is one of the diagnostic criteria to diagnose a periprosthetic joint infection (PJI). Although the test is widely available, the diagnostic accuracy of proposed cut-off levels are influenced by several factors, such as: the affected joint, co-morbid conditions, the causative microorganism and the gathering and processing of samples in the laboratory. In this narrative review we provide an overview on how and to what extent these factors can affect the synovial WBC count and PMN% in synovial fluid.

Puncture Protocol in the Diagnostic Work-Up of a Suspected Chronic Prosthetic Joint Infection of the Hip.

BACKGROUND: Diagnosing a chronic prosthetic joint infection (PJI) can be challenging. We hypothesized that obtaining preoperative tissue samples for culture in hip arthroplasty will increase the likelihood of diagnosing an infection before revision surgery. The aim of this cohort study was to determine the diagnostic accuracy of 2 tissue acquiring biopsy strategies to diagnose a PJI. METHODS: Patients with a painful hip arthroplasty, in which a chronic PJI was suspected, were included. Tissue samples were obtained either by ultrasound guidance with a 16-Gauge needle (2012-2013) or in the operating room with a thick-bore needle (2013-2016). Revision surgery tissue biopsies were used as the gold standard. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were calculated. RESULTS: A total of 16 patients in the ultrasound cohort and 29 patients in the surgical cohort were included. Thirty-one percent (n = 14) were finally diagnosed with a PJI. The addition of thick bore needle tissue biopsies resulted in 9% more diagnosed PJIs compared with synovial fluid alone. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio was 33%, 85%, 33%, 85%, 2.2, and 0.8, respectively, for the ultrasound-guided biopsy cohort and 82%, 100%, 100%, 90%, infinite, and 0.2, respectively, for the surgical biopsy cohort. CONCLUSION: Obtaining multiple good quality tissue biopsies in a sterile environment will contribute to the diagnosis of a chronic PJI of the hip, with a higher diagnostic accuracy compared with ultrasound-guided thin needle biopsies and compared with synovial fluid culture alone.

Synovial Calprotectin: An Inexpensive Biomarker to Exclude a Chronic Prosthetic Joint Infection.

BACKGROUND: To diagnose or exclude a chronic prosthetic joint infection (PJI) can be a clinical challenge. Therefore, sensitive and specific biomarkers are needed in the diagnostic work-up. Calprotectin is a protein with antimicrobial properties and is released by activated neutrophils, making it a specific marker for infection. Because of its low costs and ability to obtain a quantitative value as a point of care test, it is an attractive marker to use in clinical practice. In addition, the test is already used in routine care in most hospitals for other indications and therefore easy to implement. METHODS: Between June 2015 and June 2017 we collected synovial fluid of all consecutive patients who underwent revision surgery of a prosthetic joint because of chronic pain with or without prosthetic loosening. Synovial calprotectin was measured using a lateral flow immunoassay. A PJI was defined by the diagnostic criteria described by the Musculoskeletal Infection Society. RESULTS: Fifty-two patients with chronic pain were included. A PJI was diagnosed in 15 of 52 (29%) patients. The median calprotectin in the PJI group was 859 mg/L (interquartile range 86-1707) vs 7 mg/L (interquartile range 3-25) in the control group (P < .001). With a cut-off value of 50 mg/L, synovial calprotectin showed a sensitivity, specificity, positive predictive value, and negative predictive value of 86.7%, 91.7%, 81.3%, and 94.4%, respectively. CONCLUSION: Synovial calprotectin is a useful and cheap biomarker to use in the diagnostic work-up of patients with chronic pain, especially to exclude a PJI prior to revision surgery.

Negative Pressure Incision Management System in the Prevention of Groin Wound Infection in Vascular Surgery Patients.

Objectives. Groin wounds following vascular surgery are highly susceptible to healing disturbances, with reported site infections reaching 30%. Negative pressure incision management systems (NPIMS) are believed to positively influence the prevention of surgical wound-healing disturbances (WHD) and surgical site infections (SSI). NPIMS placed directly after closure of the surgical wound is thought to result in fewer infections; we analysed its effect on postoperative wound infections in patients after vascular surgery via the groin. Methods. From May 2012 to March 2013 we included 90 surgical patients; 40 received a NPIMS. All patients with WHDs were labelled and subanalysed for surgical site infection in case of positive microbiological culture. These infections were graded according to Szilagyi. Number of WHDs and SSIs were compared across cohorts. Results. Patient and perioperative characteristics were equal, except for a significantly higher number of emergency procedures among non-NPIMS patients. We found no significant differences in number of WHDs, SSIs, or Szilagyi grades between the two cohorts. Conclusion. The equal number of SSIs across cohorts showed that NPIMS could not reduce the number of surgical site infections after vascular groin surgery.

Survival, clinical and radiological outcome of the Zweymüller SL/Bicon-Plus total hip arthroplasty: a 15-year follow-up study.

AIM: The primary aim of this study is to analyse the long-term results of the third generation of the "Zweymüller" total hip arthroplasty (THA) comprising the SL-Plus Stem and the Bicon-Plus cup. METHODS: We evaluated 208 patients with a SL/Bicon-Plus primary THA (218 hips). Survival analysis was performed with a follow-up of 13 to 15 years. Complementary clinical and radiological analysis was performed using the "Hip Injury and Osteoarthritis Outcome Score" (HOOS) and x-rays of the hips. RESULTS: The probability of survival of the stem and cup with revision for any reason was respectively 0.96/0.97 at 10 years and 0.92/0.94 at 15 years. The probability of survival of the stem and cup with revision for aseptic loosening was respectively 0.99/0.97 at 10 years and 0.95/0.94 at 15 years. Clinical assessment of the patients, reported by the HOOS, were scored with a median for the subdivisions: symptoms 90%, pain 93%, function in daily activity 87%, function in leisure or sport 75%, and quality of life with 75%. Periprosthetic radiolucent lines were observed in half of all hips in Gruen zones 1 and 7. Mean linear wear of the polyethylene was 1.8 mm which corresponds to 0.12 mm/year. 2/3 of the hips show heterotopic ossifications, mostly Brooker type 1 and 2. CONCLUSIONS: The "third generation" Zweymüller total hip arthroplasty consisting of the SL stem and the Bicon cup has good long term results in terms of survival, clinical and radiological outcome.

Radiolunate and radioscapholunate arthrodeses as treatments for rheumatoid and psoriatic arthritis: long-term follow-up.

PURPOSE: We evaluated long-term results for radiolunate and radioscapholunate arthrodeses for patients with rheumatoid or psoriatic arthritis to determine the durability and efficacy of the procedures. The results are described and compared with those in the literature. METHODS: We carried out arthrodesis of the radiolunate joint (33 wrists) and the radioscapholunate joint (13 wrists) to achieve pain reduction and ulnar translation of the carpus in patients with rheumatoid (42 wrists) or psoriatic arthritis (4 wrists). At follow-up, 11 patients (13 wrists) had died, 2 patients (4 wrists) were lost to follow-up, and in 6 wrists an additional midcarpal arthrodesis had been performed. We evaluated the remaining 23 wrists (19 radiolunate and 4 radioscapholunate, and 1 psoriatic arthritic wrist) after a mean of 11 years. RESULTS: Clinical outcome was good, with a mean visual analog score of 2 out of 10 for pain, mean grip strength of 13 kg, and mean range of flexion-extension of 60°. Outcomes as measured by questionnaires were good. Radiographs demonstrated deterioration of all intracarpal joints as noted by an increased Larsen score and evidence of carpal translation. We noted no significant change in carpal height. CONCLUSIONS: Despite radiographic progression, radiolunate and radioscapholunate arthrodeses yield good clinical results at long-term follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.