Ultrasound-Guided Periprosthetic Biopsy in Failed Total Hip Arthroplasty: A Novel Approach to Test Infection in Patients With Dry Joints

BackgroundTo diagnose periprosthetic joint infection (PJI) preoperatively, ultrasound-guided joint aspiration (US-JA) may not be performed when effusion is minimal or absent. We aimed to report and investigate the diagnostic performance of ultrasound-guided periprosthetic biopsy (US-PB) of synovial tissue to obtain joint samples in patients without fluid around the implants.MethodsOne-hundred nine patients (55 men; mean age: 68 ± 13 years) with failed total hip arthroplasty (THA) who underwent revision surgery performed preoperative US-JA or US-PB to rule out PJI.ResultsSixty-nine of 109 patients had joint effusion and underwent US-JA, while the remaining 40 with dry joint required US-PB. Thirty-five of 109 patients (32.1%) had PJI, while 74/109 (67.9%) had aseptic THA failure. No immediate complications were observed in both groups. Technical success of US-PB was 100%, as the procedure was carried on as planned in all cases. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of US-JA were 52.2%, 97.8%, 92.3%, 80.3%, and 82.6%, while for US-PB, they were 41.7%, 100%, 100%, 80%, and 82.5%, respectively, with no significant difference (P = .779). Using the final diagnosis as reference standard, we observed a moderate agreement with both US-JA (k = 0.56) and US-PB (k = 0.50).ConclusionWe present a novel US-guided technique to biopsy periprosthetic synovial tissue of failed THA to rule out PJI. We found similar diagnostic performance as compared with traditional US-JA. This supports future larger studies on this procedure that might be applied in patients without joint effusion.     

Biomechanical and clinical study of single posterior oblique cage POLIF in the treatment of degenerative diseases of the lumbar spine

Introduction

Aim of the study was to evaluate the biomechanical stability and the clinical efficacy of a lumbar interbody fusion obtained by single oblique cage implanted by a posterior approach.

Method

Through the realization of three finite element models (FEMs), the biomechanics of POLIF was compared to PLIF and TLIF. Ninety-four patients underwent interbody fusion by POLIF with instrumented posterolateral fusion. Clinical and radiographic outcomes were evaluated at regular intervals for at least 6 months.

Results

The FEMs showed no statistically significant differences in stability in compression and flexion–extension. Mean preoperative VAS score was 7.1, decreased to 2.1 at follow-up. Mean preoperative SF-12 value was 34.5 %, increased to 75.4 % at follow-up. All patients showed a good fusion rate and no hardware failure.

Discussion

POLIF associated to instrumented posterolateral fusion is a viable and safe surgical technique, which ensures a biomechanical stability similar to other surgical techniques.

     

Normovolaemic haemodilution in spinal fusion for scoliosis

Summary Since January 1979 spinal fusions for scoliosis have been carried out at the Galeazzi Orthopaedic Institute in Milan using normovolaemic haemodilution. The object is to eliminate the risks of blood transfusion and to reduce thromboembolic complications. The method is indicated in patients who are not anaemic and when the blood loss during operation can be controlled.This paper analyses the results in 95 consecutive spinal fusion operations for scoliosis. The authors conclude that the method can be safely used for this type of operation, particularly in young patients with moderate scoliosis (a curve of 50° to 60°). The aim of the operation in these cases is to improve the appearance of the back and prevent further deformity.

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Résumé Depuis Janvier 1979, à l'Institut Orthopédique Galeazzi de Milan, les greffes pour scoliose sont réalisées en utilisant l'hémodilution normovolémique. Le but est de supprimer les risques inhérents aux transfusions sanguines et de diminuer le nombre de complications thrombo-emboliques. Cette méthode s'applique aux malades qui ne présentent pas d'anémie pré-opératoire et chez qui les pertes sanguines per-opératoires peuvent être contrôlées.Cet article analyse les résultats d'une série de 95 greffes vertébrales consécutives pour scoliose. Les auteurs concluent que cette méthode peut être utilisée en toute sécurité dans ce type d'opération, particulièrement chez les sujets jeunes avec une scoliose modérée (courbure de 50 ° à 60 °). Le but de l'intervention, dans ces cas, est d'améliorer la morphologie du dos et d'empêcher l'aggravation de la déformation.

     

Electrophysiological mechanisms of the effect of allapinin in patients with paroxysmal supraventricular tachycardia

An intracardiac electrophysiological study was undertaken to examine 15 patients with paroxysmal supraventricular tachycardias. Allapinin intravenously given in a dose of 0.4 mg/kg, was tested for effects. The agent was demonstrated to cause a substantial inhibition of rapid retrograde pathway function in atrioventricular nodal tachycardia and abnormal antero- and retrograde pathway function. This is the major aspect of the drug's action that prevents the development of episodes of paroxysmal supraventricular tachycardias. The agent fails to virtually affect the function of the atrioventricular node in the anterograde direction in the two types of the tachycardia. Thus, allapinin has the mechanism of action that is typical of quinidine-like drugs used in supraventricular tachycardias.     

Thoraco-lumbar selective fusion in adolescent idiopathic scoliosis with Lenke C modifier curves: clinical and radiographic analysis at 10-year follow-up

Purpose

To examine the radiological and clinical outcomes of a single-center case series of selective thoracic fusions (STF) in adolescent idiopathic scoliosis with Lenke C modifier curves, with a long-term follow-up.

Methods

We evaluated at 6 months and 10 years different radiological parameters on both thoracic and lumbar districts: coronal curves, sagittal curves, apical vertebral translation (AVT), and apical vertebral rotation (AVR). The clinical outcome was determined using the SRS 22 score. Data were also analyzed dividing the patients by their Risser and Lenke scores.

Results

In examining 90 patients we reported a radiological benefit from STF on both thoracic and lumbar districts. The corrections in the values of both coronal curves, AVT, and AVR are relevant at 6 months and do not significantly vary at the latest follow-up. Sagittal curves are not relevantly affected at any time point. All the SRS 22 score evaluations showed significant improvement at 6 months, in particular, the self-image analysis. A further improvement was also reported at 10 years, in particular in pain and function scores. At no time point were significant differences retrieved by comparing SRS 22 results as divided by Risser or Lenke grading systems.

Conclusions

STF is an effective treatment option both in clinical and radiographical terms. The results at 10-year follow-up confirm both the stability of the correction and the improvement of the clinical outcome scores. Risser and Lenke grading systems are not relevant variables predictive of clinical efficacy.

     

Determinants of the biomechanical and radiological outcome of surgical correction of adolescent idiopathic scoliosis surgery: the role of rod properties and patient characteristics

Purpose

Aim of the study was to evaluate the role of the mechanical properties of the rod and of the characteristics of the patients (age, skeletal maturity, BMI, and Lenke type) in determining the deformity correction, its maintenance over time and the risk of mechanical failure of the instrumentation.

Methods

From March 2011 to December 2014 120 patients affected by AIS underwent posterior instrumented fusion. Two 5.5-mm CoCr rods were implanted in all patients. For every patient, age, sex, Risser grade, Lenke type curve, flexibility of the main curve, body mass index (BMI), and percentage of correction were recorded. In all patients, the Cobb angle value and rod curvature angle (RC) were evaluated. RC changes were registered and correlated to each factor to establish a possible statistically significance in a multivariate analysis. A biomechanical model was constructed to study the influence of rod diameter and material as well as the density of the anchoring implants in determining stress and deformation of rods after contouring and implantation.

Results

Radiographic and biomechanical analysis showed a different mean rod deformation for concave and convex side: 7.8° and 3.9°, respectively. RC mean value at immediate follow-up was 21.8° for the concave side and 14.6° for the convex. At 2-year minimum follow-up, RC value increases 1.5° only for the concave side. At 3.5-year mean follow-up, RC value increases 2.7°, p = 0.003, for the concave side and 1.3° for the convex, p = 0.06. The use of the stiffest material as well as of the lowest diameter resulted in higher stresses in the rods. The use of either a low or a high instrumentation density resulted only in minor differences in the loss of correction.

Conclusions

Rod diameter and material as well as patient characteristics such as BMI, age, and Risser grade play an important role in deformity correction and its maintenance over time.

     

Ceramic–ceramic coupling with big heads: clinical outcome

The wear and the friction torque are proportional to the head diameter in THA. That is the reason why, in the past, according to Charnley’s “low friction arthroplasty”, the head diameter was as small as possible employing metal–polyethylene coupling. On the contrary with ceramic–ceramic, the head diameter raise does not increase in a considerable way neither the wear rate nor the friction torque. A bigger diameter head leads to a more stable artificial joint and to a wider range of motion. An acetabular component with a 36 mm liner-head ceramic–ceramic coupling has been developed and implanted since 2001. We performed a prospective study to investigate the dislocation rate of this new prosthesis in the first 2 years after the operation. We matched two groups of patients, comparable in diagnosis and age: the first one (370 cases, from March 2001 to March 2004) in which 36 mm heads were implanted, and the second one (223 cases, from January 2001 to March 2004) in which 28 mm heads were used. The surgical technique (postero–lateral approach), the surgeons and the stems (cemented and uncemented) were the same. We compared the number of dislocations in the two groups. There were four dislocations (1.08%) in the first group and 10 (4.48%) in the second. The data confirmed that there was a statistically significant (P = 0.011) decrease of the dislocations in the group of 36 mm heads. Moreover, we are able now to evaluate the recurrent dislocations that needed a revision: one in the group of 36 mm head (0.27%) and three in the group of 28 mm (1.34%), confirming the lower rate in the bigger heads.     

Higher risk of dural tears and recurrent herniation with lumbar micro-endoscopic discectomy

Existing studies on micro-endoscopic lumbar discectomy report similar outcomes to those of open and microdiscectomy and conflicting results on complications. We designed a randomised controlled trial to investigate the hypothesis of different outcomes and complications obtainable with the three techniques. 240 patients aged 18–65 years affected by posterior lumbar disc herniation and symptoms lasting over 6 weeks of conservative management were randomised to micro-endoscopic (group 1), micro (group 2) or open (group 3) discectomy. Exclusion criteria were less than 6 weeks of pain duration, cauda equina compromise, foraminal or extra-foraminal herniations, spinal stenosis, malignancy, previous spinal surgery, spinal deformity, concurrent infection and rheumatic disease. Surgery and follow-up were made at a single Institution. A biomedical researcher independently collected and reviewed the data. ODI, back and leg VAS and SF-36 were the outcome measures used preoperatively, postoperatively and at 6-, 12- and 24-month follow-up. 212/240 (91%) patients completed the 24-month follow-up period. VAS back and leg, ODI and SF36 scores showed clinically and statistically significant improvements within groups without significant difference among groups throughout follow-up. Dural tears, root injuries and recurrent herniations were significantly more common in group 1. Wound infections were similar in group 2 and 3, but did not affect patients in group 1. Overall costs were significantly higher in group 1 and lower in group 3. In conclusion, outcome measures are equivalent 2 years following lumbar discectomy with micro-endoscopy, microscopy or open technique, but severe complications are more likely and costs higher with micro-endoscopy.