One-year follow-up-case report of secondary tension pneumothorax in a COVID-19 pneumonia patient

PURPOSE The Coronavirus Disease 2019 (COVID-19) may result not only in acute symptoms such as severe pneumonia, but also in persisting symptoms after months. Here we present a 1~year follow-up of a patient with a secondary tension pneumothorax due to COVID-19 pneumonia. CASE PRESENTATION In May 2020, a 47-year-old male was admitted to the emergency department with fever, dry cough, and sore throat as well as acute chest pain and shortness of breath. Sputum testing (polymerase chain reaction, PCR) and computed tomography (CT) confirmed infection with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Eleven days after discharge, the patient returned to the emergency department with pronounced dyspnoea after coughing. CT showed a right-sided tension pneumothorax, which was relieved by a chest drain (Buelau) via mini open thoracotomy. For a period of 3~months following resolution of the pneumothorax the patient complained of fatigue with mild joint pain and dyspnoea. After 1~year, the patient did not suffer from any persisting symptoms. The pulmonary function and blood parameters were normal, with the exception of slightly increased levels of D-Dimer. The CT scan revealed only discrete ground glass opacities (GGO) and subpleural linear opacities. CONCLUSION Tension pneumothorax is a rare, severe complication of a SARS-CoV-2 infection but may resolve after treatment without negative long-term sequelae. LEVEL OF EVIDENCE V

Atrophy patterns in isolated subscapularis lesions

Background!#!While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon.!##!Methods!#!Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy.!##!Results!#!The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm!##!Conclusion!#!Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3

Effects of single and combined low frequency electromagnetic fields and simulated microgravity on gene expression of human mesenchymal stem cells during chondrogenesis

Introduction: Low frequency electromagnetic fields (LF-EMF) and simulated microgravity (SMG) have been observed to affect chondrogenesis. A controlled bioreactor system was developed to apply LF-EMF and SMG singly or combined during chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in 3D culture. Material and methods: An external motor gear SMG bioreactor was combined with magnetic Helmholtz coils for EMF (5 mT;15 Hz). Pellets of hMSCs (+/- TGF-beta 3)were cultured (P5) under SMG, LF-EMF, LF-EMF/SMG and control (1 g) conditions for 3 weeks. Sections were stained with safranin-O and collagen type II. Gene expression was evaluated by microarray and real-time polymerase chain reaction analysis. Results: Simulated microgravity application significantly changed gene expression;specifically, COLXA1 but also COL2A1, which represents the chondrogenic potential, were reduced (p < 0.05). Low frequency electromagnetic fields application showed no gene expression changes on a microarray basis. LF-EMF/SMG application obtained significant different expression values from cultures obtained under SMG conditions with a re-increase of COL2A1, therefore rescuing the chondrogenic potential, which had been lowered by SMG. Conclusions: Simulated microgravity lowered hypertrophy but also the chondrogenic potential of hMSCs. Combined LF-EMF/SMG provided a rescue effect of the chondrogenic potential of hMSCs although no LF-EMF effect was observed under optimal conditions. The study provides new insights into how LF-EMF and SMG affect chondrogenesis of hMSCs and how they generate interdependent effects

A Validated Preclinical Animal Model for Primary Bone Tumor Research

Funding for this study was provided by the German Research Foundation (Grant DFG WA 3606/1-1 to F. Wagner and Grant HO 5056/1-1 to B.M. Holzapfel), the Australian Research Council (Future Fellowship Program) and the Technical University Munich Hans Fischer Senior Fellowship (D.W. Hutmacher), and a Research Fellowship from the National Health and Medical Research Council (#1044091 to J.-P. Lévesque

Case report - calcification of the medial collateral ligament of the knee with simultaneous calcifying tendinitis of the rotator cuff

Calcification of the medial collateral ligament (MCL) of the knee is a very rare disease. We report on a case of a patient with a calcifying lesion within the MCL and simultaneous calcifying tendinitis of the rotator cuff in both shoulders. Case presentation: Calcification of the MCL was diagnosed both via x-ray and magnetic resonance imaging (MRI) and was successfully treated surgically. Calcifying tendinitis of the rotator cuff was successfully treated applying conservative methods. Conclusion: This is the first case report of a patient suffering from both a calcifying lesion within the medial collateral ligament and calcifying tendinitis of the rotator cuff in both shoulders. Clinical symptoms, radio-morphological characteristics and macroscopic features were very similar and therefore it can be postulated that the underlying pathophysiology is the same in both diseases. Our experience suggests that magnetic resonance imaging and x-ray are invaluable tools for the diagnosis of this inflammatory calcifying disease of the ligament, and that surgical repair provides a good outcome if conservative treatment fails. It seems that calcification of the MCL is more likely to require surgery than calcifying tendinitis of the rotator cuff. However, the exact reason for this remains unclear to date

Pedicled perforator flaps for mid-tibial soft tissue reconstruction in medically compromised patients

Background: The soft tissue of the central pretibial area is difficult to reconstruct often requiring free tissue transfer. Especially medi- cally compromised patients are not ideal candidates for free tissue transfer and may benefit from expeditiously harvested local flaps with limited donor site morbidity. As muscle flaps are rare, pedi- cled flaps based on lateral perforators represent an alternative as the arc of rotation can often be limited to 90 °. Material and Methods: A retrospective analysis of patient data was conducted to identify patients over the age of 60 years with comor- bidities that underwent pretibial soft tissue reconstruction with a single-pedicle perforator flap. Patient demographics, size and cause of the defect, flap dimension, arc of rotation and complications were recorded. Results: Five patients with an average age of 71.4 years were in- cluded. The arc of rotation was 69 °, all flaps healed. There were two recurrences of osteomyelitis. Conclusion: Lateral perforators originating from the anterior tib- ial artery or peroneal artery are adequate source vessels for single pedicled perforator flaps even in medically compromised patients. A perforator located proximal to the defect allows limiting the arcof rotation to less than 90 °, which increases the safety of the flap. Patients benefit from a simple procedure without a microvascular anastomosis and a donor site confined to one extremit

In vitro evaluation of antibacterial efficacy of vancomycin-loaded suture tapes and cerclage wires

Usage of implants containing antibiotic agents has been a common strategy to prevent implant related infections in orthopedic surgery. Unfortunately, most implants with microbial repellent properties are characterized by accessibility limitations during daily clinical practice. Aim of this in vitro study was to investigate whether suture tapes and cerclage wires, which were treated with vancomycin, show a sustainable antibacterial activity. For this purpose, we used 24 stainless steel wire cerclages and 24 ultra-high molecular weight polyethylene and polyester suture tape test bodies. The test bodies were incubated for 30 min. in 100 mg/ml vancomycin solution or equivalent volumes of 0.9% NaCl. After measuring the initial solution uptake of the test bodies, antibacterial efficacy via agar diffusion test with Staphylococcus aureus and vancomycin elution tests were performed 1, 2, 3, and 6 days after incubation. Vancomycin-loaded tapes as well as vancomycin-loaded cerclage wires demonstrated increased bacterial growth inhibition when compared to NaCl-treated controls. Vancomycin-loaded tapes showed an additional twofold and eightfold increase of bacterial growth inhibition compared to vancomycin-loaded wires at day 1 and 2, respectively. Elution tests at day 1 revealed high levels of vancomycin concentration in vancomycin loaded tapes and wires. Additionally, the concentration in vancomycin loaded tapes was 14-fold higher when compared to vancomycin loaded wires. Incubating suture tapes and cerclage wires in vancomycin solution showed a good short-term antibacterial activity compared to controls. Considering the ease of vancomycin application on suture tapes or wires, our method could represent an attractive therapeutic strategy in biofilm prevention in orthopedic surgery

Revision knee arthroplasty with rotating hinge systems in patients with gross ligament instability

Purpose: The clinical and radiographic outcomes after revision total knee arthroplasty (TKA) for instability with two rotating hinge knee prostheses were compared. Methods: Fifty-one patients revised for TKA instability were prospectively randomized to either the Link Endo-Model (N = 26) or the EnduRo (N = 25). Clinical and radiographic outcome scores were compared pre-operatively and at 12 months’ follow-up. Failure mechanisms were recorded. Results: Age, BMI, operation, and tourniquet-time did not differ significantly between groups. Radiographic evaluation demonstrated correct implant alignment. The Endo-Model was implanted with a higher slope (p = 0.0001) and the mechanical lower extremity axis was straighter (p = 0.0323). Except for the patient function Knee Society Score and the Physical Health Component Summary Score in the EnduRo group, all clinical scores (range of motion/knee function Knee Society Score/Oxford Knee Score/Visual Analog Scale/Mental Health Component Summary Score) improved significantly for both prosthesis designs during the follow-up period. The Visual Analog Scale and Mental Health Component Summary score were significantly better (p = 0.045 and p = 0.0148) in the Endo-Model group at the 12 months’ follow-up. In the EnduRo group 2 patients (8%) and in the Endo-Model group 1 patient (3.8%) had to be revised for infection. Conclusion: Both prosthetic designs provide significant improvement in pain and function scores after TKA revision for gross instability. We found slight advantages in favor of the Endo-Model; however, no design yielded superior results throughout the study.</p