Osteology, Volume 3, Issue 1 (March 2023) – 5 articles

Protrusio acetabuli is a unique osteological condition that has been long described in the literature and is known to potentially increase both the surgical complexity and the risk of complications when performing total hip arthroplasty. Although grading systems for native hip protrusio have been described in the past, there has not yet been a widely adopted classification system that categorizes the condition into separate classes in order to guide management. We propose a novel classification system with the goal of simplifying and standardizing the management of protrusio acetabuli in the context of modern total hip arthroplasty. This classification system describes protrusio based on the relationship of the femoral head to the ilioischial and iliopectineal lines, allowing for a more reproducible and consistent categorization of pathology. We also discuss general recommendations and technical pearls for total hip arthroplasty in the protrusio patient population, including the use of strategic soft tissue releases, fluoroscopy, navigation, bone graft, and augments. Full article

There is evidence to suggest that restoration of major/rare biominerals by supplementation can produce osteogenic and anti-resorptive effects in humans. LithoLexal^® is a natural extract harvested from a marine alga, Lithothamnion sp., with a porous microstructure and multimolecular composition rich in calcium (32% w/w) and magnesium (2.2% w/w) together with ~72 trace bioelements. In vitro, LithoLexal^® demonstrated cellular-level osteogenic efficacy through enhancing the maturation and activity of pre-osteoblasts. This extract also expressed the ability to suppress osteoclastogenesis by downregulating the pro-resorptive cytokines TNF-α and IL-1β and the master regulator of inflammation NF-κB. Parathyroid hormone inhibition of parathyroid hormone secretion is another bioactivity of LithoLexal^® Bone reported with both short- and long-term administration at a longer duration and higher magnitude than what calcium carbonate could induce. Due to these bioactivities that affect pathogenetic factors of osteoporosis, LithoLexal^® Bone is referred to as a disease-modifying adjunctive therapy (DMAT). In postmenopausal animal models, LithoLexal^® monotherapy preserved bone mineral density, microarchitecture, and biomechanical properties, while calcium carbonate failed to produce significant outcomes. The pro-resorptive effect of a high-fat diet was also efficiently counteracted in vivo by supplementary LithoLexal^®. A large clinical trial on postmenopausal women verified the mitigating effects of LithoLexal^® Bone on bone resorption and turnover rate. The characteristic composition of LithoLexal^® together with its lattice microstructure are suggested to underlie its in vivo bioactivities. In conclusion, adjunctive therapy with LithoLexal^® Bone is an attractive option for clinical prevention and treatment of osteopenia/osteoporosis. Full article

Vitamin D plays a pivotal role in calcium metabolism and bone mineralization. Sufficient vitamin D levels are important for the health and functionality of the musculoskeletal system. Hypovitaminosis D is a phenomenon affecting orthopedic patients worldwide. This study researched whether most orthopedic patients in two different cities of different countries had hypovitaminosis D, whether there was a correlation between sunshine hours and vitamin D serum levels, and whether hours of sunshine alone were enough to achieve vitamin D sufficiency among orthopedic patients regardless of their activities. The vitamin D serum levels of 500 orthopedic patients in Regensburg and 500 in Patras were assessed, in addition to their medical histories. The mean sunshine hours throughout the year were also calculated. Both the German and Greek groups showed hypovitaminosis D. Older patients were more affected. Although there were more hours of sunshine in Greece, Greek orthopedic patients also showed hypovitaminosis D. Hypovitaminosis D affects orthopedic patients independent of their latitude. Supplementation of vitamin D may be considered among orthopedic patients to achieve sufficient levels in serum. Sufficient vitamin D levels may be helpful for the treatment of orthopedic patients, reduce the negative effects of operations or postoperational settings. Full article

I previously reported that F-box/leucine-rich repeat protein 14 (FBXL14) expressed in periosteum-derived cells, and F-box and WD-40 domain-containing protein 2 (FBXW2) in the periosteum form a fiber-like structure. Here, two culture medium conditions, that is, media with and without ascorbic acid, were compared during explant culture. In the absence of ascorbic acid, the expression patterns of osteocalcin, FBXW2, and elastin were compared using fluorescent immunostaining during weeks 3–5. By observing the periosteum, cambium layer and bone, I demonstrated FBXL14 expression in micro-vessels and bone lacuna. Fluorescent immunostaining revealed that, without ascorbic acid, the FBXL14 layer was thin. Conversely, in the presence of ascorbic acid, FBXL14 formed a thick membrane-like structure inside the periosteum, and the multilayer of periosteum-derived cells (PDCs) was strong. The expression patterns of osteocalcin and FBXW2 were similar. Elastin retained its fiber structure for up to five weeks. Although osteocalcin and FBXW2 were expressed in regions similar to elastin, they could not retain their fiber structures. In conclusion, FBXL14 appears to play a role in preparing a native scaffold for forming a multilayered sheet of PDCs inside the periosteum. FBXW2 and osteocalcin appear to separate from elastic fibers during calcification. Full article