KHỚP HÁNG CÁN NGẮN: PHÂN LOẠI VÀ KẾT QUẢ PHẪU THUẬT

Mục tiêu: Cập nhật, hệ thống lại phân loại cũng như kết quả trên lâm sàng của khớp háng cán ngắn. Đối tượng và phương pháp: Đối tượng của chúng tôi là các bài báo trên dữ liệu Pubmed, qua các tài liệu tìm được tiến hành phân tích, phân loại khớp háng cán ngắn và tổng hợp kết quả điều trị phẫu thuật theo từng phân loại đó. Kết quả: Có hai phân loại được sử dụng nhiều hơn cả đó là phân loại theo Khanuja H.S. (4 loại) và phân loại theo Hội nghiên cứu và phẫu thuật khớp (Joint implant surgery and research foundation-JISRF) 2 loại: Nhóm cố định vùng cổ và nhóm cố định vùng hành xương. Tại Việt Nam chỉ mới có khớp háng cán ngắn Spiron. Kết luận: khớp háng cán ngắn được phân loại tùy theo hình dáng, vị trí cố định và mức độ bảo tồn xương. Kết quả theo dõi chủ yếu tập trung trong thời gian ngắn hạn và trung hạn và tương đối khả quan.

Human osteoblasts obtained from distinct periarticular sites demonstrate differences in biological function in vitro

Aims Accumulated evidence indicates that local cell origins may ingrain differences in the phenotypic activity of human osteoblasts. We hypothesized that these differences may also exist in osteoblasts harvested from the same bone type at periarticular sites, including those adjacent to the fixation sites for total joint implant components. Methods Human osteoblasts were obtained from the acetabulum and femoral neck of seven patients undergoing total hip arthroplasty (THA) and from the femoral and tibial cuts of six patients undergoing total knee arthroplasty (TKA). Osteoblasts were extracted from the usually discarded bone via enzyme digestion, characterized by flow cytometry, and cultured to passage three before measurement of metabolic activity, collagen production, alkaline phosphatase (ALP) expression, and mineralization. Results Osteoblasts from the acetabulum showed lower proliferation (p = 0.034), cumulative collagen release (p < 0.001), and ALP expression (p = 0.009), and produced less mineral (p = 0.006) than those from the femoral neck. Osteoblasts from the tibia produced significantly less collagen (p = 0.021) and showed lower ALP expression than those from the distal femur. Conclusion We have demonstrated for the first time an anatomical regional variation in the biological behaviours of osteoblasts on either side of the hip and knee joint. The lower osteoblast proliferation, matrix production, and mineralization from the acetabulum compared to those from the proximal femur may be reflected in differences in bone formation and implant fixation at these sites. Cite this article: Bone Joint Res 2021;10(9):611–618.

Design and Evaluation of a Hip Joint Implant Wear Simulator

Every year a high number of total hip arthroplasty is reported worldwide and an increase in this number is expected. Several factors may cause hip wear, such as osteoarthritis, obesity, traffic accidents and sport practicing. Wear is a concern when considering hip prostheses, since a prosthesis presents finite life that in many cases is shorter than patient life, and leads to substitution. Also, research is constant and new developments have to be tested, which leads to the necessity of testing devices that reproduce real conditions of hip joint implant functioning. This work describes a low-cost device, according to the ISO 12242. The equipment was built, a set of three commercially available prostheses was tested and the results show wear values coherent with those found in literature. It was found a value of wear rate of (13.30 ± 3,81) mg/106 cycles; wear factor found was (0.41 ± 0,09) x 10-6 mm3 /Nm. After testing, the device was evaluated and no component presented significant wear. Keywords: Hip joint simulator; Prostheses; Wear; Arthroplasty; Test machine.

The T Cell Repertoires from Nickel Sensitized Joint Implant Failure Patients

Nickel (Ni2+) is one of the most common allergens, affecting around 10–15% of the general population. As the demand for orthopedic implant surgery rises, the number of surgical revisions due to joint implant failure also increases. There is evidence that some patients develop joint failure due to an immune response to a component of the implant, and we have found that Ni2+ is an especially important cause. Hence, understanding the mechanisms by which Ni2+ allergy induces joint implant failure becomes a critical research question. The structural basis of Ni2+ activation of pathogenic T cells is still not clear. The purpose of this study was to characterize Ni2+-reactive T cell repertoires derived from the peripheral blood of joint failure patients due to Ni2+ sensitization using single-cell sequencing techniques. We stimulated the proliferation of Ni2+ -reactive T cells from two implant failure patients in vitro, and sorted them for single-cell VDJ sequencing (10× genomics). We identified 2650 productive V-J spanning pairs. Both TCR α chains and β chains were enriched. TRBV18 usage is the highest in the P7 CD4+ population (18.1%), and TRBV5-1 usage is the highest in the P7 CD8+ population (12.1%). TRBV19 and TRBV20-1 segments are present in a high percentage of both P7 and P9 sequenced T cells. Remarkably, the alpha and beta chain combination of TRAV41-TRBV18 accounts for 13.5% of the CD4+ population of P7 patient. Compared to current Ni specific T cell repertoire studies of contact dermatitis, the Vα and Vβ usages of these joint implant failure patients were different. This could be due to the different availability of self-peptides in these two different tissues. However, TRBV19 (Vβ17) was among frequently used TCR β chains, which are common in previous reports. This implies that some pathogenic T cells could be similar in Ni2+ hypersensitivities in skin and joints. The alignment of the TCR CDR3β sequences showed a conserved glutamic acid (Glu) that could potentially interact with Ni2+. The study of these Ni2+ specific TCRs may shed light on the molecular mechanism of T cell activation by low molecular weight chemical haptens.