The Effect of Surgeon Volume on Revision for Periprosthetic Joint Infection: An Analysis of 602,919 Primary Total Knee Arthroplasties

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication of total knee arthroplasty (TKA). An association between low surgeon volume and higher rates of infection following primary TKA has been suggested. The purpose of the present study was to determine if there was a relationship between surgeon volume and the rate of revision for infection after primary TKA.

METHODS

We searched the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to identify all primary TKA procedures that were performed for the treatment of osteoarthritis from September 1, 1999, to December 31, 2020, and were subsequently revised because of infection. Surgeon volume was defined as the annual volume of procedures performed by a surgeon during the same year in which the primary TKA (which was subsequently revised for infection) was performed. Surgeon volume was defined as <25, 25 to 49, 50 to 74, 75 to 99, or ≥100 primary TKA procedures/year. The cumulative percent revision (CPR) for infection was determined with use of Kaplan-Meier estimates. Cox proportional hazards methods were used to compare rates of revision for infection by surgeon volume, with subanalyses for patellar resurfacing and polyethylene use. Further analyses for patients <65 years of age and male patients were undertaken.

RESULTS

Overall, 602,919 primary TKA procedures were performed for the treatment of osteoarthritis, of which 5,295 were revised because of infection. High-volume surgeons (≥100 TKAs/year) had a significantly lower rate of revision for infection, with a CPR at 1 and 19 years of 0.4% (95% confidence interval [CI], 0.3 to 0.4) and 1.5% (95% CI, 1.2 to 2.0), respectively, compared with 0.6% (95% CI, 0.5 to 0.7) and 2.1% (95% CI, 1.8 to 2.3), respectively, for low-volume surgeons (<25 TKAs/year). Hazard ratios (HRs), adjusted for age and sex, comparing these 2 groups varied, depending on the time point, between 3.07 (95% CI, 2.02 to 4.68) and 1.44 (95% CI, 1.26 to 1.63) but remained significant (p < 0.001). When the analysis was adjusted for age, sex, American Society of Anesthesiologists (ASA) classification, and body mass index (BMI), there remained an increased risk of revision for PJI for all lower surgeon volume levels in comparison with the high- surgeon-volume group (≥100 TKAs/year). The results were similar when stratified by patellar resurfacing and cross-linked polyethylene (XLPE) and adjusted for age and sex.

CONCLUSIONS

High-volume surgeons had lower rates of revision for infection. A better understanding of how surgical volume contributes to decreasing this complication is important and requires in-depth study.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

A prospective review of appetite loss and recovery time in primary joint replacement patients

INTRODUCTION

Appetite loss is commonly reported by patients following major surgery, including total joint arthroplasty (TJA). A number of studies have examined related problems, particularly in relation to physiological responses to surgery. However, no published paper has looked specifically at the duration of appetite loss in total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients.

METHODS

A simple, established appetite screening tool was administered preoperatively and at 2-week intervals postoperatively in 50 TJA patients until appetite levels returned to preoperative levels. The results were examined for various descriptive parameters and compared using the chi-squared test.

RESULTS

Thirty-three patients underwent TKA and 17 THA. There were 27 female and 23 male patients. No patients were lost to follow-up. The median time for return of appetite in both male and female patients was 4 weeks (interquartile range [IQR]: male, 2-4; female, 4-6). The median time for return of appetite was 4 weeks both in TKA patients (IQR 4-6) and in those undergoing THA (IQR 4-4). The time to return of appetite was not significantly associated with either the gender of the patients (p=0.13) or the type of joint replacement (p=0.49).

CONCLUSIONS

The study provides a clear time frame for return of appetite in uncomplicated primary joint replacements. This is a commonly noted patient problem that has not previously been specifically reviewed.

Venous thromboembolism risk assessments in acute care

This article is aimed at nurses and other health professionals working in clinical practice and involved in venous thromboembolism (VTE) risk assessments. The article adds to the body of published literature relating to patient risk assessment for VTE by exploring practical clinical perspectives of introducing a sustainable risk assessment process. It reports on a series of small scale changes carried out during a project in an acute medicine unit at the Heart of England NHS Foundation Trust in Birmingham, which aimed to improve the level of compliance with carrying out VTE risk assessments and administering prophylaxis. The results of two audits conducted over a seven-month period at the beginning and end of the project illustrate an improvement in compliance from 6.25% to 62.5%. The article concludes that leadership from medical consultants acting as clinical champions is imperative and that nurses and healthcare assistants also have a pivotal role in promoting patient assessments, and in maintaining the momentum and sustainability of VTE risk assessments in clinical areas.

Impact of malocclusion and orthognathic reconstruction surgery on resonance and articulatory function: an examination of variability in five cases

Articulatory patterns and nasal resonance were assessed before and 6 months after orthognathic reconstruction surgery in five patients with dentofacial deformities. Perceptual and physiological assessments showed disorders of nasality and articulatory function preoperatively, two patients being hyponasal, and one hypernasal. Four patients had mild articulatory deficits, and four had reduced maximal lip or tongue pressures. Operation resulted in different patterns of change. Nasality deteriorated in three patients and articulatory precision and intelligibility improved in only one patient and showed no change in the other four. Operation improved interlabial pressures in three patients, while its impact on tongue pressures varied, being improved in one case, deteriorating in one, and remaining unchanged in the other three. The variability in the results highlights the need for routine assessment of speech and resonance before and after orthognathic reconstruction.

Search for bipolar disorder susceptibility loci: the application of a modified genome scan concentrating on gene-rich regions

Conducting genome wide screens for evidence of genetic linkage has become a well-established method for identifying regions of the human genome harboring susceptibility loci for complex disorders. For bipolar disorder, a number of such studies have been performed, and several regions of the genome have potentially been implicated in the disorder. The classic design for a genome screen involves examining polymorphic genetic markers spaced at regular intervals throughout the genome, typically every 10 cM, for evidence of linkage. An alternative design, based on the observation that genes do not appear to be evenly distributed, was proposed, enabling the number of markers examined in a genome wide screen to be reduced. This article describes the application of such a modified screen to a collection of 48 Irish families with bipolar disorder, comprising a total of 82 affected sib-pairs. From the results obtained a number of regions are highlighted for further study. One of these regions (17q11.1-q12) coincides with the location of a candidate gene, the serotonin transporter, whereas others concur with the findings of published studies. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:728-732, 2000.

Substituted indoles as potent and orally active 5-lipoxygenase activating protein (FLAP) inhibitors

This paper reports on the SAR investigation of inhibitors of 5-lipoxygenase activating protein (FLAP) based on MK-0591. Emphasis was made on modifications to the nature of the link between the indole and the quinoline moieties, to the substitution pattern around the two heterocycles and to possible replacements of the quinoline moiety. Lead optimization culminated in (3-[1-(4-chlorobenzyl)-3-(t-butylthio)-5-(pyridin-2-ylmethoxy)-ind ol-2-yl]-2,2-dimethylpropanoic acid (18k), as a potent inhibitor of leukotriene biosynthesis that is well absorbed and active in functional models.

Practice and education of nurse anaesthetists

A survey was conducted of the anaesthesia services provided by nurses and the education available to them in this field in 107 countries. Among the procedures carried out were general anaesthesia, spinal blocks and tracheal intubation. The implications of the findings for health planning and policy-making are discussed with particular reference to workforce structure and women's involvement in it.

A series of non-quinoline cysLT1 receptor antagonists: SAR study on pyridyl analogs of Singulair

The structure-activity relationship of a series of styrylpyridine analogs of MK-0476 (montelukast, Singulair) is described. This work has led to the identification of a number of potent and orally active cysLT1 receptor (LTD4 receptor) antagonists including 2ab (L-733,321) as an optimized candidate.

Effects of a selective phosphodiesterase IV inhibitor (CDP-840) in a leukotriene-dependent non-human primate model of allergic asthma

The activity of CDP-840, a novel, selective phosphodiesterase IV inhibitor was determined in a leukotriene-dependent non-human primate model of allergic asthma. Measurements of specific airway resistance (sRaw) were recorded in a dual chamber plethysmograph for 1 h and 3-5 h after challenge of allergic conscious squirrel monkeys with an aerosol of ascaris antigen. Orally administered CDP-840 (10 mg/kg; 1 h before challenge) produced partial inhibition (41 and 45%, respectively) of both the acute (1 h post antigen) response and the late (3-5 h post antigen) response to antigen but failed to alter the response to an aerosol of leukotriene D4. In a second series of experiments, intravenous CDP-840 (5 mg/kg; 30 min before challenge) showed improved potency, producing 82% inhibition of the early and 51% inhibition of the late phase response. CDP-840 was inactive when tested intravenously at 1 mg/kg and was inactive against the 3-5 h response when administered after the early phase response (5 mg/kg; i.v. 60 min post antigen challenge). The novel phosphodiesterase IV inhibitor CDP-840 selectively inhibited antigen-induced bronchoconstriction in conscious squirrel monkeys. This effect appears to be independent of any direct bronchodilator action. It is concluded that the activity of CDP-840 in this model may be due to an inhibitory effect on mediator (e.g., leukotriene) release.

Effects of a selective phosphodiesterase IV inhibitor (CDP-840) in a leukotriene-dependent non-human primate model of allergic asthma

The activity of CDP-840, a novel, selective phosphodiesterase IV inhibitor was determined in a leukotriene-dependent non-human primate model of allergic asthma. Measurements of specific airway resistance (sRaw) were recorded in a dual chamber plethysmograph for 1 h and 3-5 h after challenge of allergic conscious squirrel monkeys with an aerosol of ascaris antigen. Orally administered CDP-840 (10 mg/kg; 1 h before challenge) produced partial inhibition (41 and 45%, respectively) of both the acute (1 h post antigen) response and the late (3-5 h post antigen) response to antigen but failed to alter the response to an aerosol of leukotriene D4. In a second series of experiments, intravenous CDP-840 (5 mg/kg; 30 min before challenge) showed improved potency, producing 82% inhibition of the early and 51% inhibition of the late phase response. CDP-840 was inactive when tested intravenously at 1 mg/kg and was inactive against the 3-5 h response when administered after the early phase response (5 mg/kg; i.v. 60 min post antigen challenge). The novel phosphodiesterase IV inhibitor CDP-840 selectively inhibited antigen-induced bronchoconstriction in conscious squirrel monkeys. This effect appears to be independent of any direct bronchodilator action. It is concluded that the activity of CDP-840 in this model may be due to an inhibitory effect on mediator (e.g., leukotriene) release.Key words: selective phosphodiesterase IV inhibitor, CDP-840, antigen-induced bronchoconstriction, non-human primate.

Substituted (pyridylmethoxy)naphthalenes as potent and orally active 5-lipoxygenase inhibitors; synthesis, biological profile, and pharmacokinetics of L-739,010

Dioxabicyclooctanyl naphthalenenitriles have been reported as a class of potent and nonredox 5-lipoxygenase (5-LO) inhibitors. These bicyclo derivatives were shown to be metabolically more stable than their tetrahydropyranyl counterparts but were not well orally absorbed. Replacement of the phenyl ring in the naphthalenenitrile 1 by a pyridine ring leads to the potent and orally absorbed inhibitor 3g (L-739,010, 2-cyano-4-(3-furyl)-7-[[6-[3-(3-hydroxy-6,8-dioxabicyclo[3.2.1] octanyl)]-2-pyridyl]methoxy]naphthalene). Compound 3g inhibits 5-HPETE production by human 5-LO and LTB4 biosynthesis by human PMN leukocytes and human whole blood (IC50S of 20, 1.6, and 42 nM, respectively). Derivative 3g is orally active in the rat pleurisy model (inhibition of LTB4, ED50 = 0.3 mg/kg) and in the anesthetized dog model (inhibition of ex vivo whole blood LTB4 and urinary LTE4, ED50 = 0.45 and 0.23 microgram/kg/min, respectively, i.v. infusion). In addition, 3g shows excellent functional activity against ovalbumin-induced dyspnea in rats (60% inhibition at 0.5 mg/kg, 4 h pretreatment) and Ascaris-induced bronchoconstriction in conscious sheep (50% and > 85% inhibition in early and late phases, respectively at 2.5 micrograms/kg/min, i.v. infusion) and, more particularly in the conscious antigen sensitive squirrel monkey model (53% inhibition of the increase in RL and 76% in the decrease of Cdyn, at 0.1 mg/kg, po). In rats and dogs, 3g presents excellent pharmacokinetics (estimated half-lives of 5 and 16 h, respectively) and bioavailabilities (26% and 73% when dosed as its hydrochloride salt at doses of 20 and 10 mg/kg, respectively, in methocel suspension). Based on its overall biological profile, compound 3g has been selected for preclinical animal toxicity studies.

Dioxabicyclooctanyl naphthalenenitriles as nonredox 5-lipoxygenase inhibitors: structure-activity relationship study directed toward the improvement of metabolic stability

Naphthalenic lignan lactone 3a (L-702,539), a potent and selective 5-lipoxygenase (5-LO) inhibitor, is extensively metabolized at two different sites: the tetrahydropyran and the lactone rings. Early knowledge of the metabolic pathways triggered and directed a structure-activity relationship study aimed toward the improvement of metabolic stability in this series. The best modifications discovered, i.e., replacement of the lactone ring by a nitrile group, replacement of the tetrahydropyran ring by a 6,8-dioxabicyclo[3.2.1]octanyl moiety, and replacement of the pendant phenyl ring by a 3-furyl ring, were incorporated in a single molecule to produce inhibitor 9ac (L-708,780). Compound 9ac inhibits the oxidation of arachidonic acid to 5-hydroperoxy-eicosatetraenoic acid by 5-LO (IC50 = 190 nM) and the formation of leukotriene B4 in human polymorphonuclear leukocytes (IC50 = 3 nM) as well as in human whole blood (IC50 = 150 nM). The good inhibitory profile shown by naphthalenenitrile 9ac is accompanied by an improved resistance to oxidative metabolism. In addition, 9ac is orally active in the functional model of antigen-induced bronchoconstriction in allergic squirrel monkeys (95% inhibition at 0.1 mg/kg).

Insensitivity to anti-müllerian hormone due to a mutation in the human anti-müllerian hormone receptor

Anti-Müllerian hormone (AMH) and its receptor are involved in the regression of Müllerian ducts in male fetuses. We have now cloned and mapped the human AMH receptor gene and provide genetic proof that it is required for AMH signalling, by identifying a mutation in the AMH receptor in a patient with persistent Müllerian duct syndrome. The mutation destroys the invariant dinucleotide at the 5' end of the second intron, generating two abnormal mRNAs, one missing the second exon, required for ligand binding, and the other incorporating the first 12 bases of the second intron. The similar phenotypes observed in AMH-deficient and AMH receptor-deficient individuals indicate that the AMH signalling machinery is remarkably simple, consisting of one ligand and one type II receptor.