A case report on Mycobacterium houstonense infection after total hip arthroplasty.

BACKGROUND: Mycobacterium houstonense is a category of rapidly growing mycobacteria that is gram-positive, acid-fast, polycrystalline, and non-spore-forming. There have been few reports of human infection caused by Mycobacterium houstonense worldwide. CASE PRESENTATION: We present a case of chronic periprosthetic joint infection caused by Mycobacterium houstonense in an elderly female patient. The patient developed signs of infection after undergoing total hip arthroplasty. Despite receiving antibiotic treatment and revision surgery, the signs of infection recurred repeatedly. Multiple bacterial cultures during the treatment period were negative. Later, we identified the pathogenic bacteria Mycobacterium houstonense through mNGS testing, isolated the bacteria from the ultrasonically centrifuged fluid of the prosthesis and obtained drug sensitivity results. Finally, we performed a revision surgery and treated the patient with moxifloxacin and clindamycin. After treatment, the patient did not show signs of infection recurrence during 24 months of follow-up. CONCLUSION: Through a relevant literature search, we believe that Mycobacterium houstonense may show higher sensitivity to amikacin and quinolone antibiotics. Additionally, clarifying occult infection sources through methods such as gene testing will improve the diagnosis and treatment of periprosthetic joint infection.

Alteration in Microcirculation With Osteonecrosis of the Femoral Head: A Study of Dynamic Contrast-Enhanced MRI.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is commonly used in clinical practice to detect tumor blood supply, and it has recently been applied to assess skeletal vasculature. In this study, we retrospectively analyzed DCE-MRI data from 37 patients with osteonecrosis of the femoral head to evaluate alterations in microvascular circulation of the femoral head. Time-intensity curves (TICs) in the region of interest were classified into different lesion stages. In the greater trochanter area, extracellular space volume per unit volume of tissue was significantly higher in Association Research Circulation Osseous (ARCO) stage III than in ARCO stage II (P<.05 and power ≥ 0.8), while other parameters showed no statistical difference (P>.05 and/or power < 0.8). In the necrotic area, contrast enhancement ratio and maximum slope of increase were significantly lower in ARCO stage III than in ARCO stage II (P<.05 and power ≥ 0.8), while other parameters showed no statistical difference (P>.05 and/or power < 0.8). In the repair reaction area, all parameters were significantly higher in ARCO stage III than in ARCO stage II (P<.05 and power ≥ 0.8). TIC classification showed that the greater trochanter area mainly exhibited type C (plateau type), the necrotic area mainly exhibited type B (out-flow type), and the repair reaction area mainly exhibited type A (inflow type). We believe that the exchange capacity of the vessels has a much greater impact on femoral head necrosis than the number of vessels, while the generation of the repair area greatly affects the prognosis of femoral head necrosis. These findings suggest that DCE-MRI can provide a good assessment of osteonecrosis of the femoral head perfusion and can serve as a new reference for clinical treatment decisions. [Orthopedics. 202x;4x(x):xx-xx.].

[Study of virtual reality technology combined with reduction plasty of femoral head in treatment of coxa plana].

Objective: To explore the feasibility of virtual reality (VR) technology combined with reduction plasty of the femoral head in the treatment of coxa plana and evaluate its effectiveness. Methods: Three patients with coxa plana were selected as the research objects between October 2018 and October 2020, all of them were male, aged 15-24 years. Preoperative surgical planning was performed using VR technology; 256 rows of CT data of hip joint were imported into software to generate three-dimensional (3D) imaging, simulate the surgical process, and determine the matching relationship between the femoral head and acetabulum. According to the preoperative planning, reduction plasty of the femoral head under surgical dislocation, relative lengthening of the femoral neck, and periacetabular osteotomy were performed. The reduction of osteotomy size of femoral head and rotation angle of acetabulum were confirmed by C-arm fluoroscopy. The healing of the osteotomy were assessed by radiological examination after operation. The Harris score of hip function and visual analogue scale (VAS) score were recorded before and after operation. The femoral head roundness index, center-edge (CE) angle, and femoral head coverage were measured by X-ray films. Results: Three operations were completed successfully, and the operation time was 460, 450, and 435 minutes, and the intraoperative blood loss was 733, 716, and 829 mL, respectively. All patients were infused with 3 U suspension oligoleucocyte and 300 mL frozen virus inactivated plasma after operation. No postoperative complication occurred, such as infection and deep vein thrombosis. Three patients were followed up 25, 30, and 15 months, respectively. CT showed good healing of the osteotomy at 3 months after operation. The VAS score and Harris score at 12 months after operation and at last follow-up, as well as the femoral head rounding index, hip CE angle, and femoral head coverage at 12 months after operation significantly improved when compared with those before operation; the hip function was evaluated by the Harris score at 12 months after operation, and all three patients were good. Conclusion: VR technology combined with reduction plasty of the femoral head can achieve satisfactory short-term effectiveness in the treatment of coxa plana.

[Study on bone microstructure and pathology of type L2 and L3 osteonecrosis of the femoral head specimens classified by China-Japan Friendship Hospital classification based on "three-columns structure"].

Objective: To analyze the similarities and differences of bone microstructure and apoptosis phenotype of lateral column, middle column, and medial column in type L2 and L3 osteonecrosis of the femoral head (ONFH) specimens classified by China-Japan Friendship Hospital (CJFH) classification, so as to carry out a quantitative study of ONFH "three-columns structure theory" and to provide research support for the treatment of ONFH by rotational osteotomy through the base of femoral neck. Methods: Discarded femoral head specimens from 16 patients (16 hips) with CJFH type L2 and L3 ONFH undergone total hip arthroplasty between April 2020 and February 2021 were selected as the research objects. First, the "three-column structure" of the femoral head was three-dimensionally segmented by Micro-CT, and the bone volume to total volume (BV/TV), bone surface area to bone volume ratio (BS/BV), trabecular spacing/separation (Tb.Sp), trabecular thickness (Tb.Th), and trabecular number (Tb.N) in the lateral column, middle column, and medial column were analyzed to compare the similarities and differences of parameters related to bone mass and trabecular structure among the three columns. Then, the specimens were cut with a oscillating saw and made into paraffin sections for HE staining and immunohistochemical staining of B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax). The differences of apoptosis phenotype between the three columns of ONFH samples of CJFH type L2 and L3 were evaluated by comparing the rate of empty lacunae and the rate of positive cells of immunohistochemical staining. Results: There were significant differences in BV/TV, Tb.Th, and Tb.N among the three columns of CJFH type L2 ONFH femoral head ( P<0.05), with the largest in the medial column and the smallest in the lateral column; BS/BV and Tb.Sp of the lateral column were significantly greater than those of the medial column and middle column ( P<0.05), no significant difference was found between the middle column and medial column ( P>0.05). There was no significant difference in the bone parameters between the three columns of the CJFH type L3 ONFH femoral head ( P>0.05). There was no significant difference in the rate of empty lacunae between the three columns of the CJFH type L2 and L3 ONFH femoral head ( P>0.05). Immunohistochemical staining showed that a large number of tissue sections were detached, and only a small amount of non-specific staining was found in the sections without detachment, so the positive cell rate could not be calculated. Conclusion: The middle and medial columns of the CJFH type L2 ONFH has better trabecular structures than the lateral column, and there is no significant difference in trabecular structures among the three columns of the CJFH type L3 ONFH.

[Anatomic and clinical study of virtual reality technology assisted modified transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head].

OBJECTIVE: To explore the feasibility and effectiveness of the modified transtrochanteric curved varus osteotomy in the treatment of osteonecrosis of the femoral head (ONFH), clarify the key points of the operation, and then explore the effectiveness of modified transtrochanteric curved varus osteotomy in the treatment of ONFH assisted by virtual reality (VR) technology. METHODS: A 70-year-old adult female cadaver without formaldehyde fixation was taken. It was confirmed by anatomical study and simulated operation that the modified transtrochanteric curved varus osteotomy was suitable for type C1 (patients with involvement of the lateral column of the femoral head but partial integrity) classified by the Japanese Osteonecrosis Investigation Committee (JIC). Between October 2018 and August 2020, 11 patients (17 hips) with ONFH who met the selection criteria were treated with modified transtrochanteric curved varus osteotomy. VR technology was used to simulate varus osteotomy before operation to predict the angle of valgus of lower limbs and pronation of femoral head. Osteotomy, valgus, and pronation were performed according to the results of preoperative planning. After operation, X-ray films were used to evaluate the changes of varus and neck-shaft angle after VR assisted surgery, and Harris score was used to evaluate the hip function. RESULTS: The anteroposterior pelvic X-ray film was rechecked at 2 days after operation, of which 3 hips were consistent with the planned varus angle of VR preoperative planning, and the error value of varus angle of the remaining 14 hips was 1°-4°. The difference between VR preoperative planning and 2 days after operation was 6°-16°. All 11 patients were followed up 11-28 months, with an average of 19.2 months. All incisions healed by first intension. During the follow-up, 1 case (1 hip) developed greater trochanter fracture at 2 months after operation and was treated with open reduction and plate and screw internal fixation; 1 case (1 hip) had delayed healing at osteotomy at 4 months after operation and healed at 3 months after local injection of platelet rich plasma and oral supplementation of kidney blood-strengthening soup. At last follow-up, 17 hip osteotomies healed. The Harris score was 84.0±5.6, which was significantly higher than that before operation (57.2±5.5) ( t=-14.107, P=0.000); hip function was excellent in 2 hips, good in 13 hips, and fair in 2 hips. CONCLUSION: The modified transtrochanteric curved varus osteotomy for the treatment of ONFH is theoretically feasible, and the short-term effectiveness of this operation combined with VR technology is satisfactory.

[Genetic analysis and prenatal diagnosis of a fetus with harlequin ichthyosis].

OBJECTIVE: To carry out variant analysis for a fetus suspected with harlequin ichthyosis (HI). METHODS: Whole exome sequencing (WES) was employed to detect potential variant in the fetus. Suspected variant was validated by Sanger sequencing. RESULTS: A homozygous missense variant c.6858delT (p.F2286fs) was detected in the fetus, for which both parents were heterozygous carriers. Pathological analysis confirmed the diagnosis of HI. CONCLUSION: The c.6858delT variant of the ABCA12 gene probably underlies the disease in the fetus.

Association of C8orf4 expression with its methylation status, aberrant ß-catenin expression, and the development of cervical squamous cell carcinoma.

Chromosome 8 open reading frame 4 (C8orf4) is an activator of Wnt signaling pathway, and participates in the tumorigenesis and progression of many tumors. The expression levels of C8orf4 and ß-catenin were assessed via immunohistochemical staining in 100 cervical squamous cell carcinoma (CSCC) tissues, 50 high-grade squamous intraepithelial lesions (HSILs), 50 low-grade squamous intraepithelial lesions (LSILs), and 50 normal cervical tissues. Bisulfite sequencing polymerase chain reaction analysis was used to examine the methylation status of the C8orf4 locus in CSCC and normal cervical tissues. The expression rates of C8orf4 and ß-catenin were significantly higher in CSCCs or HSILs than in LSILs or normal cervical tissues (P < .05). C8orf4 expression was positively correlated with the poor differentiation of CSCCs (P = .009), and with aberrant expression of ß-catenin in CSCCs (P = .002) and squamous intraepithelial lesions (P < .001). The methylation rate of C8orf4 in CSCCs was significantly lower than that in normal cervical tissues (P = .001). The Cancer Genome Atlas genomics data also confirmed that the mRNA expression of C8orf4 was positively associated with the copy number alteration of C8orf4 (correlation coefficient = 0.213, P < .001), and negatively correlated with the methylation level of C8orf4 (correlation coefficient = -0.408, P < .001). In conclusion, the expressions of C8orf4 and ß-catenin were synergistically increased in CSCCs and HSILs and higher than those in LSILs and normal cervical tissues. The methylation level of C8orf4 is decreased in CSCCs and is responsible for the increased expression of C8orf4.