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.

[The first Belgian hand transplantation case. Nine years follow-up]. / Le premier cas belge de transplantation de main. Résultat à neuf ans.

The authors report the clinical result at 9 years followup of a unilateral hand transplantation performed on the dominant side after traumatic forearm amputation. The patient is back to work and sporting activities. The allograft has been fully incorporated into his self-image. The satisfaction index is 10/10, the DASH 5/100, and the 400-points score 68.1 %. The Lanzetta HTSS score is 91 (excellent). Good function of extrinsic and intrinsic muscles is observed. The grasping strength is markedly decreased (7.4 % as compared to the normal non-dominant side). The patient has experienced several rejection episodes, controlled by the immunosuppressant drugs.

Endometrial expression of selected transcripts involved in prostaglandin synthesis in cows with endometritis.

Several cytokines and prostaglandins play an important role in preparing the endometrium for implantation and mediating pro-inflammatory events. The aim of the present study was to examine mRNA expression of interleukin 1alpha (IL-1alpha), interleukin receptor antagonist (IL-1-RN), cytosolic prostaglandin E synthase (cPGES), microsomal PGES (mPGES-1 and mPGES-2) and lipocalin-type PGDS (L-PGDS) in the bovine endometrium. Endometrial epithelium samples were collected ex vivo from cows with different status of health at day 21-27 postpartum on a dairy farm. Three groups (n=9 animals each) were defined: (1) healthy cows with no signs of endometritis (control group), (2) cows with subclinical endometritis, and (3) cows with signs of clinical endometritis. Oestrous cycle-dependent mRNA expression pattern was investigated using bovine endometrial epithelial cells from healthy uteri collected at the abattoir. These uteri were classified into post-ovulatory, early-to-mid luteal, late luteal or pre-ovulatory phase (n=8 animals for each cycle phase). After collecting endometrial epithelium using the cytobrush-method, mRNA analysis was performed by real-time RT-PCR. L-PGDS, IL-1alpha and IL-1-RN mRNA were expressed significantly higher (P<0.05) in the endometrium of cows with subclinical or clinical endometritis compared with healthy cows. A twofold lower cPGES mRNA expression (P<0.05) was detected in cows with subclinical endometritis compared to healthy cows. L-PGDS and IL-1-RN mRNA expression was increased (P<0.05) after ovulation compared with the pre-ovulatory or luteal phase, respectively. These results support the hypothesis that a dys-regulated cytokine and/or prostaglandin profile in the uterus could be induced by subclinical endometritis or clinical endometritis.

Atypical acute rejection after hand transplantation.

Skin rejection after hand transplantation is characterized by a maculopapular erythematous rash that may be diffuse, patchy or focal, and distributed over forearms and dorsum of the hands. This 'classical' pattern of rejection usually spares the skin of the palm and does not affect the nails. Herein, we report the experience on four cases presenting with an 'atypical' pattern of rejection that is novel in involving the palmar skin and the nails. All patients were young and exposed to repetitive and persistent mechanical stress of the palm. Characteristic features of rejection included a desquamative rash associated with dry skin, red papules, scaling and lichenification localized to the palm. Skin lesions were associated with nail dystrophy, degeneration, deformation or loss. Histology of the skin and nail bed revealed a lymphocytic infiltrate with predominance of T cells (CD3+, CD4+ and CD8+), with small numbers of B cells (CD20+ and CD79a+) and a low number of Forkhead transcription factor 3 (FOXP3)-positive cells in one patient. The lesions persisted over weeks to months, responded poorly to steroid treatment and were managed with antithymocyte globulin (ATG; Thymoglobulin, Genzyme, Cambridge, MA), alemtuzumab and/or intensified maintenance immunosuppression.

Predictors of mortality: a comparison between two burn wound treatment policies.

Retrospective review of outcomes and experiences of a single burn centre between two time periods during which a new wound care technique was employed after the first period. The time period was divided into two: 1977-1984 and 1984-1990. Due to the use of cerium nitrate-silver sulphadiazine, the introduction of serial excision and grafting became possible in the second time period. Multivariate risk-analysis was done by logistic regression analysis. The mortality rate decreased from 13.7% (1997-1983) to 4.7% (1984-1990). Results of multiple logistic regression analysis indicate that the change in periods was advantageous for patients with >50% TBSA, within the age group, 0 to 30 years. Obviously, the care which a patient receives has improved significantly. Many developments occurred simultaneously and it appears impossible to conclude that only the use of cerium nitrate-silver sulphadiazine was the reason for improved survival. Nevertheless, the use of cerium nitrate-silver sulphadiazine enables sequential excision and grafting and in consequence allows for many of these developments to occur.

Efficacy of a mouthrinse based on hydroxyapatite to reduce initial bacterial colonisation in situ.

OBJECTIVE: The present in situ - investigation aimed to specify the impact of pure hydroxyapatite microclusters on initial bioadhesion and bacterial colonization at the tooth surface. DESIGN: Pellicle formation was carried out in situ on bovine enamel slabs (9 subjects). After 1min of pellicle formation rinses with 8ml of hydroxyapatite (HA) microclusters (5%) in bidestilled water or chlorhexidine 0.2% were performed. As negative control no rinse was adopted. In situ biofilm formation was promoted by the intraoral slab exposure for 8h overnight. Afterwards initial bacterial adhesion was quantified by DAPI staining and bacterial viability was determined in vivo/in vitro by live/dead-staining (BacLight). SEM analysis evaluated the efficacy of the mouthrinse to accumulate hydroxyapatite microclusters at the specimens' surface and spit-out samples of the testsolution were investigated by TEM. RESULTS: Compared to the control (2.36×106±2.01×106bacteria/cm2), significantly reduced amounts of adherent bacteria were detected on specimens rinsed with chlorhexidine 0.2% (8.73×104±1.37×105bacteria/cm2) and likewise after rinses with the hydroxyapatite testsolution (2.08×105±2.85×105bacteria/cm2, p<0.001). No demonstrable effect of HA-particles on Streptococcus mutans viability could be shown. SEM analysis confirmed the temporary adsorption of hydroxyapatite microclusters at the tooth surface. Adhesive interactions of HA-particles with oral bacteria were shown by TEM. CONCLUSION: Hydroxyapatite microclusters reduced initial bacterial adhesion to enamel in situ considerably and could therefore sensibly supplement current approaches in dental prophylaxis.

Necrotizing fasciitis of the first ray caused by group A streptococcus.

Necrotizing fasciitis of the hand is a rare clinical entity, frequently with devastating functional consequences. A case of necrotizing fasciitis of the thumb and thenar eminence caused by Group A Streptococcus is reported and the management of this condition in the upper limb discussed.

The first Belgian hand transplantation--37 month term results.

The first Belgian hand transplant was a 22 year-old man with a traumatic amputation of his dominant hand at the junction of the middle and distal thirds of the forearm. The donor and recipient had three HLA mismatches. The cross-match was negative. The total ischaemic time was slightly over 6 hours. Immunosuppression included antithymocyte globulins at induction and tacrolimus, mycophenolate mofetil and prednisolone as induction and maintenance therapy. There has been no episode of rejection. The only significant complications, except for transient hyperglycaemia, were psychological. At 37 months post-transplantation, the patient has fully incorporated his transplant into his self-image and is back at work. He has good sensibility (two-point discrimination of 6mm at the thumb and index finger pulps), acceptable wrist and finger motion with functioning intrinsic muscles. According to Chen's criteria, the result is good to excellent.

Hypothenar fat pad flap surgery for end stage and recurrent carpal tunnel syndrome.

One year follow-up results after hypothenar fat pad flap surgery for recurrent and end stage carpal tunnel syndrome (CTS) are reported. Before surgery, the patients' complaints with a recurrent CTS were mainly pain and return of pathological symptoms (tingling, nocturnal pain, etc.) whereas the patients with end stage CTS reported problems of loss of sensation. Both groups (8 patients in each group) reported a limited functional status for activity of daily living (ADL) prior to surgery. Evaluations of sensibility, strength, pain and Boston Carpal Tunnel Questionnaire were made preoperatively and postoperatively at 3, 6 and 12 months. The major clinical issues for both groups were statistically significantly improved after one year, but already significant results were noted after 3 months. We confirm that the hypothenar fat pad flap is a good solution for recurrent CTS. Moreover, end stage CTS could be a new and promising indication for the use of this vascularized flap.

Complications of gamma knife surgery for Parkinson disease.

BACKGROUND: Many medical centers throughout the world offer radiosurgery with the gamma knife (GK) for pallidotomy and thalamotomy as a safe and effective alternative to radiofrequency ablative surgery and deep brain stimulation for Parkinson disease (PD). The reported incidence of significant complications varies considerably, and the long-term complication rate remains unknown. DESIGN: We describe 8 patients seen during an 8-month period referred for complications of GK surgery for PD. RESULTS: Of the 8 patients, 1 died as a result of complications, including dysphagia and aspiration pneumonia. Other complications included hemiplegia, homonymous visual field deficit, hand weakness, dysarthria, hypophonia, aphasia, arm and face numbness, and pseudobulbar laughter. In all patients, lesions were significantly off target. CONCLUSIONS: The 8 patients with PD seen in referral at our center for complications of GK surgery highlight a spectrum of potential problems associated with this procedure. These include lesion accuracy and size and the delayed development of neurological complications secondary to radiation necrosis. Gamma knife surgery may have a higher complication rate than has been previously appreciated due to delayed onset and underreporting. We believe that the risk-benefit ratio of the GK will require further scrutiny when considering pallidotomy or thalamotomy in patients with PD. Physicians using this technique should carefully follow up patients postoperatively for delayed complications, and fully inform patients of these potential risks.

Incidence, determinants and significance of fixed retrograde conduction in the region of the atrioventricular node. Evidence for retrograde atrioventricular nodal bypass tracts.

Of 104 consecutive patients studied in our laboratory with His bundle electrograms, atrial and ventricular pacing and the atrial and ventricular extrastimulus techniques, 18 patients in whom the existence and utilization of ventriculoatrial (V-A) bypass tracts were excluded demonstrated evidence for fixed and rapid retrograde conduction in the region of the atrioventricular node (A-V) as suggested by the following: (1) short (36 +/- 2 msec [mean +/- standard error of mean]) and constant retrograde H2-A2 intervals during retrograde refractory period studies; (2) significantly (P less than 0.025) better V-A than A-V conduction; (3) significantly (P less than 0.025) shorter retrograde functional refractory period of the V-A conducting system than of the A-V conduction system; and (4) the retrograde effective refractory period of the A=V nodal region was not attainable in any of the 18 patients. Fourteen of the 18 patients (77 percent) had a history of palpitations and 10 (51 percent) had documented paroxysmal supraventricular tachycardia; in 13 (72 percent) single echoes or sustained reentrant supraventricular tachycardia, or both, could be induced during atrial pacing or atrial premature stimulation studies, or both. During tachycardia all these 13 patients had a short (37 +/- 2.4 msec) and constant conduction time in the retrograde limb (H-Ae interval) of the reentrant circuit that was identical to the H2-A2 interval. In conclusion, fixed and rapid retrograde conduction in the region of the A-V node (1) is seen in approximately 17 percent of patients, (2) is associated with a large incidence of reentrant paroxysmal supraventricular tachycardia, and (3) suggests the presence of A-V nodal bypass tracts (intranodal or extranodal functioning in retrograde manner).

Methods used for liver computed tomography scanning in community radiology practice.

RATIONALE AND OBJECTIVES: A survey conducted in 1987 of mostly academic radiologists revealed that 8 of 22 (36%) respondents used bolus enhanced dynamic technique when performing computed tomography (CT) of the liver. In the current study, the authors performed a new survey of private practice radiologists that was over four times larger and had more comprehensive questions. METHODS: An 18-item questionnaire was sent to 260 members of the American College of Radiology. The answers from 98 usable responses were tallied and analyzed. RESULTS: Forty-six percent of the radiologists polled use bolus enhanced dynamic CT. Thirty-three percent still use ionic contrast, and a significantly lower iodine dose was used when nonionic contrast was chosen. CONCLUSIONS: There is general agreement in the imaging literature that dynamic enhanced scanning is the method of choice for detecting liver masses with CT. The authors speculate that cost and convenience considerations strongly influence such decisions, because less than 50% of radiologists we polled use this somewhat more expensive and time-consuming technique.

Breath-holding capability of adults. Implications for spiral computed tomography, fast-acquisition magnetic resonance imaging, and angiography.

PURPOSE: The breath-holding capabilities of various groups of individuals were evaluated to develop protocols so that patients undergoing spiral computed tomography (CT), digital angiography, and breath-hold magnetic resonance imaging (MRI) can be studied successfully. METHODS: Twenty-five outpatients and 25 inpatients (all adults) were studied before undergoing body CT. Each subject was asked to hold his or her breath for as long as possible. Then each patient was asked to perform as many repetitive 12-second breath holds as possible. These data were correlated with demographic and historical information. RESULTS: The maximum breath-hold time for inpatients and those outpatients who were heavy smokers or had chronic obstructive pulmonary disease (COPD) or congestive heart failure (CHF) was 18 to 32 seconds (95% confidence interval) with a mean of 25 seconds. For all other outpatients, breath-hold time was 38 to 56 seconds (mean = 45 seconds). The 95% confidence interval for the number of 12-second breath holds for these two groups was 4 to 6 breath holds (mean = 4.9) and 6 to 7 breath holds (mean = 6.6), respectively. One inpatient could not hold his breath at all and three others were only able to hold their breath once for short periods. The sex and age of the patient had no significant effect on breath-holding performance. CONCLUSIONS: Breath-holding protocols must account for the diminished capabilities of most inpatients, and outpatients who are heavy smokers or have COPD or CHF. Most outpatients who are not heavy smokers or without COPD or CHF can achieve a single breath hold of 38 seconds, or up to six 12-second breath holds.

Effects of a multicomponent intervention on functional outcomes and process of care in hospitalized older patients: a randomized controlled trial of Acute Care for Elders (ACE) in a community hospital.

BACKGROUND: Older persons frequently experience a decline in function following an acute medical illness and hospitalization. OBJECTIVE: To test the hypothesis that a multicomponent intervention, called Acute Care for Elders (ACE), will improve functional outcomes and the process of care in hospitalized older patients. DESIGN: Randomized controlled trial. SETTING: Community teaching hospital. PATIENTS: A total of 1,531 community-dwelling patients, aged 70 or older, admitted for an acute medical illness between November 1994 and May 1997. INTERVENTION: ACE includes a specially designed environment (with, for example, carpeting and uncluttered hallways); patient-centered care, including nursing care plans for prevention of disability and rehabilitation; planning for patient discharge to home; and review of medical care to prevent iatrogenic illness. MEASUREMENTS: The main outcome was change in the number of independent activities of daily living (ADL) from 2 weeks before admission (baseline) to discharge. Secondary outcomes included resource use, implementation of orders to promote function, and patient and provider satisfaction. RESULTS: Self-reported measures of function did not differ at discharge between the intervention and usual care groups by intention-to-treat analysis. The composite outcome of ADL decline from baseline or nursing home placement was less frequent in the intervention group at discharge (34% vs 40%; P = .027) and during the year following hospitalization (P = .022). There were no significant group differences in hospital length of stay and costs, home healthcare visits, or readmissions. Nursing care plans to promote independent function were more often implemented in the intervention group (79% vs 50%; P = .001), physical therapy consults were obtained more frequently (42% vs 36%; P = .027), and restraints were applied to fewer patients (2% vs 6%; P = .001). Satisfaction with care was higher for the intervention group than the usual care group among patients, caregivers, physicians, and nurses (P < .05). CONCLUSIONS: ACE in a community hospital improved the process of care and patient and provider satisfaction without increasing hospital length of stay or costs. A lower frequency of the composite outcome ADL decline or nursing home placement may indicate potentially beneficial effects on patient outcomes.

Scanning electron microscopic analysis of the stapled microvascular anastomosis in the rabbit.

BACKGROUND: Despite the high percentages of experimental and clinical patency rates achieved using so-called mechanical anastomotic devices (Unilink; 3M, St. Paul, MN; vascular staples) they remain little known and occasionally used. METHODS: The VCS Auto Suture microstapler technique for microvascular anastomosis was tested experimentally and compared with the conventional "gold standard" 10/0 end-to-end microvascular technique. Thirty carotid arteries on one side of 30 rabbits were stapled using nonpenetrating 0.9-mm (small) VCS Auto Suture microclips, and the other 30 carotid arteries on the other side were sutured in a conventional way with 10/0 monofilament nylon. A 100% patency rate was achieved on both sides. Biopsy was performed in five groups of rabbits at different time intervals postoperatively, and the specimens were examined under scanning electron microscopy. RESULTS: All 60 anastomoses were patent. Histomorphologic examination of the anastomotic site revealed no major differences between sutured and stapled groups. CONCLUSIONS: Stapled microvascular anastomosis technique is fast and reliable.

Diffusion-weighted MR imaging of the normal human spinal cord in vivo.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging is a robust technique for evaluation of a variety of neurologic diseases affecting the brain, and might also have applications in the spinal cord. The purpose of this study was to determine the feasibility of obtaining in vivo diffusion-weighted images of the human spinal cord, to calculate normal apparent diffusion coefficient (ADC) values, and to assess cord anisotropy. METHODS: Fifteen healthy volunteers were imaged using a multi-shot, navigator-corrected, spin-echo, echo-planar pulse sequence. Axial images of the cervical spinal cord were obtained with diffusion gradients applied along three orthogonal axes (6 b values each), and ADC values were calculated for white and gray matter. RESULTS: With the diffusion gradients perpendicular to the orientation of the white matter tracts, spinal cord white matter was hyperintense to central gray matter at all b values. This was also the case at low b values with the diffusion gradients parallel to the white matter tracts; however, at higher b values, the relative signal intensity of gray and white matter reversed. With the diffusion gradients perpendicular to spinal cord, mean ADC values ranged from 0.40 to 0.57 x 10(-3) mm2/s for white and gray matter. With the diffusion gradients parallel to the white matter tracts, calculated ADC values were significantly higher. There was a statistically significant difference between the ADCs of white versus gray matter with all three gradient directions. Strong diffusional anisotropy was observed in spinal cord white matter. CONCLUSION: Small field-of-view diffusion-weighted images of the human spinal cord can be acquired in vivo with reasonable scan times. Diffusion within spinal cord white matter is highly anisotropic.

MR characteristics of muslin-induced optic neuropathy: report of two cases and review of the literature.

Muslin-induced optic neuropathy is a rarely reported but important cause of delayed visual loss after repair of intracranial aneurysms. Most of the previously reported cases were published before the introduction of MR imaging. We describe the clinical features and MR appearance of two cases of delayed visual loss due to "muslinoma," and compare them with the 21 cases reported in the literature.

Isolated straight sinus and deep cerebral venous thrombosis: successful treatment with local infusion of urokinase. Case report.

A 23-year-old woman presented with headache and progressive lethargy. The diagnosis of isolated thrombosis of the straight sinus and of the deep cerebral venous system was established using cranial computerized tomography, magnetic resonance imaging, phase-contrast magnetic resonance venography, and cerebral angiography. Because of the rapid deterioration in the patient's clinical condition, the authors used direct transcatheter infusion of urokinase into the straight sinus. This treatment resulted in a successful outcome.

Intratumoral LAK cell and interleukin-2 therapy of human gliomas.

Adoptive immunotherapy using lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2) offers the possibility of a new treatment for patients with malignant glial tumors. In a clinical trial, the effectiveness of a 5-day treatment cycle of direct intratumoral administration of both LAK cells and IL-2 via a reservoir/catheter system in patients with recurrent malignant gliomas was studied. Ten patients were entered into the study, nine of whom were treated with 15 cycles of LAK cells (0.9 to 21.0 x 10(9) cells) and IL-2 (49 to 450 x 10(3) U/kg). The 10th patient in the study was not treated because of the onset of severe neurological deficits prior to beginning immunotherapy. Of the nine patients treated, one had a partial tumor response to immunotherapy as documented by computerized tomography. Neurological side effects occurred in all patients undergoing treatment and were related to increases in cerebral edema that appeared to be mediated by the immunotherapy. This report demonstrates the present limitations of regional adoptive immunotherapy with LAK cells and IL-2 in the treatment of human glial tumors.