Desmoid Fibromatosis Fused With a Lipoma in the Upper Arm

Lipoma, the most common mesenchymal tumor, often appears as a slow-growing mass in the musculoskeletal system (MSK). While generally non-invasive, their location can cause symptoms. Desmoid fibromatosis (DF), a rare and locally aggressive neoplasm, poses challenges in MSK system diagnosis and management due to its infiltrative nature. Despite lacking metastatic potential, DF has a high recurrence rate, classifying it as "intermediate, locally aggressive" in the WHO classification. Collaborative efforts among orthopedic surgeons, radiologists, and pathologists are crucial for accurate diagnosis and treatment planning for all tumors of the MSK system. This case report presents the first documented example of a DF within a lipoma, highlighting the challenges of diagnosing and treating musculoskeletal tumors.

Biochemical changes of the pericellular matrix and spatial chondrocyte organization-Two highly interconnected hallmarks of osteoarthritis

During osteoarthritis, chondrocytes change their spatial arrangement from single to double strings, then to small and big clusters. This change in pattern has recently been established as an image-based biomarker for osteoarthritis. The pericellular matrix (PCM) appears to degrade together alongside cellular reorganization. The aim of this study was to characterize this PCM-degradation based on different cellular patterns. We additionally wanted to identify the earliest time point of PCM-breakdown in this physiopathological model. To this end, cartilage samples were selected according to their predominant cellular pattern. Qualitative analysis of PCM degradation was performed immunohistochemically by analysing five main PCM components: collagen type VI, perlecan, collagen type III, biglycan, and fibrillin-1 (n = 6 patients). Their protein content was quantified by enzyme-linked immunosorbent assay (127 patients). Accompanying spatial cellular rearrangement, the PCM is progressively destroyed, with a pericellular signal loss in fluorescence microscopy for collagen type VI, perlecan, and biglycan. This loss in protein signal is accompanied by a reduction in total protein content from single strings to big clusters (P < .001 for collagen type VI, P = .003 for perlecan, and P < .001 for biglycan). As a result of an increase in the number of cells from single strings to big clusters, the amount of protein available per cell also decreases for collagen type III and fibrillin-1, where total protein levels remain constant. Biochemical changes of the PCM and cellular rearrangement are thus highly interconnected hallmarks of osteoarthritis. Interestingly, the earliest point in time for a relevant PCM impairment appears to be at the transition to small clusters.

Changes in stiffness and biochemical composition of the pericellular matrix as a function of spatial chondrocyte organisation in osteoarthritic cartilage

OBJECTIVE

During osteoarthritis (OA), chondrocytes seem to change their spatial arrangement from single to double strings, small and big clusters. Since the pericellular matrix (PCM) appears to degrade alongside this reorganisation, it has been suggested that spatial patterns act as an image-based biomarker for OA. The aim of this study was to establish the functional relevance of spatial organisation in articular cartilage.

METHOD

Cartilage samples were selected according to their predominant spatial cellular pattern. Young's modulus of their PCM was measured by atomic force microscopy (AFM) (∼500 measurements/pattern). The distribution of two major PCM components (collagen type VI and perlecan) was analysed by immunohistochemistry (8 patients) and protein content quantified by enzyme-linked immunosorbent assay (ELISA) (58 patients).

RESULTS

PCM stiffness significantly decreased with the development from single to double strings (p = 0.030), from double strings to small clusters (p = 0.015), and from small clusters to big clusters (p < 0.001). At the same time, the initially compact collagen type VI and perlecan staining progressively weakened and was less focalised. The earliest point with a significant reduction in protein content as shown by ELISA was the transition from single strings to small clusters for collagen type VI (p = 0.016) and from double strings to small clusters for perlecan (p = 0.008), with the lowest amounts for both proteins seen in big clusters.

CONCLUSIONS

This study demonstrates the functional relevance of spatial chondrocyte organisation as an image-based biomarker. At the transition from single to double strings PCM stiffness decreases, followed by protein degradation from double strings to small clusters.

Estimating Braking Performance in Osteoarthritis of the Knee or Hip with a Reaction Timer

Objective

To investigate if testing in a brake simulator can be replaced by a simple reaction timer setup imitating the ergonomic conditions of emergency braking when evaluating the ability to drive in patients with musculoskeletal problems of the lower extremities.

Methods

A cross‐sectional survey was performed in the Department of Orthopaedic Surgery in our University Hospital from October 2014 until May 2015. Patients attending our department with either osteoarthritis or arthroplasty of the knee or hip were asked to participate in the study if they had a valid driving license. The age limit was from 18 to 85 years. Both women and men were included. Registered demographic data were patient age, height, sex, body weight, and body mass index. Braking performance (brake response time [BRT]) was evaluated in a brake simulator that was embedded into a real car cabin (10 measurements). The values obtained were compared with those registered when simply testing (5 measurements) those patients with a normal reaction timer setup that imitated the sitting position in a car. Kendall's tau correlation coefficient was calculated between the values obtained from the brake simulator with those from the reaction timer setup.

Results

Altogether, 137 patients (median age 67 years [range, 24–89 years]) with either osteoarthritis of the knee (n = 55) or hip (n = 82) were tested. Age was comparable in both collectives (P = 0.807). The mean body height was 1.70 m in both groups. Knee patients presented with a higher body weight of approximately 5 kg (P = 0.014) and consequently also had a higher body mass index (P = 0.023). The median BRT in the brake simulator was 628 ms (range, 390–1444 ms) for all subjects: 592 ms (range, 418–1146 ms) in the hip group and 696 ms (range, 390–1444 ms) in the knee group. Measurement values obtained by the reaction timer were significantly (P < 0.001) higher by approximately 15% (SD, 22%) than those measured in the brake simulator. A moderate correlation was found between the reaction timer and the brake simulator, with a Kendall's tau of 0.449 (P < 0.001) for all patients. Interestingly, hip patients showed a higher correlation (τ = 0.471) than knee patients (τ = 0.263).

Conclusion

Even though the measured correlations do not allow us to make a definite statement concerning braking performance, especially in knee patients, a simple reaction timer test can provide a low‐cost first estimate of BRT for patients and their treating physicians. For forensic statements, the brake simulator will, however, remain the gold standard.

Influence of spine surgery on the ability to perform an emergency stop while driving a car

BACKGROUND

Spinal surgeries have strongly increased in number over the past decade. The question of when it is safe to resume driving is thereby one the most frequently asked questions that patients ask of their treating physician.

OBJECTIVE

The aim of this study was to assess braking performance before and after spine surgery.

METHODS

Reaction time, foot transfer time (together brake response time [BRT]), and brake force (BF) were evaluated in a drive simulator. A longitudinal patient cohort (n= 27) was tested preoperatively and at the first follow-up. A cross-sectional cohort (n= 27) was tested at > 1 year postoperatively. The values from these groups were compared with a healthy age-matched control group of 24 volunteers.

RESULTS

No significant improvement in BRT was seen in lumbar fusion three months postoperatively (p= 0.597); BF was even weaker than it was preoperatively (p= 0.044). In comparison to the control group (median BRT 479 ms), preoperative BRT was already impaired in lumbar fusion patients (median 560 ms), representing an increased braking distance of 2.25 m at 100 km/h.

CONCLUSION

Although most patients performed adequately, about one third presented critical braking performance. Risk factors for impaired braking may include scheduled multisegmental fusion surgery, female sex, and pain.

Bacterial adhesion to suture material in a contaminated wound model: Comparison of monofilament, braided, and barbed sutures

Contaminated suture material plays an important role in the physiopathology of surgical site infections. Recently, suture material has been developed characterized by barbs projecting from a monofilament base. Claimed advantages for barbed sutures are a shortened wound closure time and reduced maximum wound tension. It has also been suggested that these sutures would be advantageous microbiologically. The aim of this study was to test the microbiological characteristics of the barbed Quill in comparison to the monofilament Ethilon II and the braided sutures Vicryl and triclosan-coated Vicryl Plus. In our study, sutures were cultivated on color-change agar with Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium, Escherichia coli, and Pseudomonas aeruginosa and the halo size was measured. In a second study arm with longer cultivation bacterial growth was followed by antibiotic treatment. Ethilon II and Quill showed good comparable results, whereas large halos were found around Vicryl. Vicryl Plus results depended on triclosan sensitivity. After longer bacterial cultivation and antibiotic treatment, halos were up to 3.6 times smaller on Quill than on Vicryl (p < 0.001), but 1.4 times larger than on Ethilon II (p < 0.001) regarding S. aureus. Confocal microscopy analysis showed bacterial colonization between the braided filaments on Vicryl and beneath the barbs on Quill. From a microbiological perspective, barbed sutures can be recommended in aseptic surgery, but should only be used carefully in septic surgery. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:925-933, 2017.

Pivotal roles for eomesodermin during axis formation, epithelium-to-mesenchyme transition and endoderm specification in the mouse

The T-box transcription factor eomesodermin (Eomes) has been implicated as an important component in germ layer induction and patterning in vertebrate embryos. In the mouse, Eomes is essential for development of the trophectoderm lineage and Eomes loss-of-function mutants arrest at implantation. Here, we have used a novel Eomes conditional allele to test Eomes functions in the embryo proper. Eomes-deficient embryos express both Fgf8 and its downstream target Snail at normal levels but surprisingly fail to downregulate E-cadherin. Eomes functional loss thus efficiently and profoundly blocks EMT and concomitant mesoderm delamination. Marker analysis as well as fate-mapping and chimera studies demonstrate for the first time that Eomes is required for specification of the definitive endoderm lineage. We also describe developmental abnormalities in Eomes/Nodal double heterozygotes, and demonstrate that these phenotypes reflect Eomes and Nodal interactions in different tissue sites. Collectively, our experiments establish that Eomes is a key regulator of anteroposterior axis formation, EMT and definitive endoderm specification in the mouse.