Joseph L. Roberts

In preclinical research focused on bone fracture repair, a significant gap exists in understanding and incorporating key variables that influence homeostasis and pathophysiological processes. Factors such as immune system responses, sex differences, pain and innervation, and microbiota are often overlooked. Preclinical studies frequently rely on rodent models housed under sterile, specific pathogen‐free conditions, resulting in naïve immune responses. Additionally, these studies typically use only one sex, fail to monitor stress behaviors, and do not assess infections or commensal microorganisms. While such controlled approaches enable the study of essential mechanisms, they may hinder the successful translation of findings to immunocompetent and diverse human populations, who do not live in sterile environments and vary widely in biological sex, gender, age, immune history, and living conditions. Here, we summarize the material presented at the Preclinical Models Section and International Section of Fracture Repair Workshop held during the 2026 Orthopaedic Research Society (ORS) Annual Meeting in Charlotte, North Carolina.

Robinow syndrome has characteristic craniofacial and dental features and can be caused by gain- or loss-of-function variants in Wnt family member 5A (WNT5A) non-canonical signaling. The craniofacial and dental manifestation of Robinow syndrome is heterogenous, as is the effect of altered Wnt5a in animal models. The relationship between Wnt5a and craniofacial and dental phenotypes is not fully understood. To investigate the role of Wnt5a in bone during craniofacial and dental development, we utilized a Wnt5a conditional loss-of-function (LOF: Wnt5a^fl/fl;Ctsk^cre) and a Wnt5a conditional gain-of-function (GOF: Rosa26-LSL-Wnt5a;Ctsk^cre) model to determine the effect of both LOF and GOF of Wnt5a in bone cells during craniofacial and dental development. Postnatal day 10 conditional LOF Wnt5a, GOF Wnt5a, and control skulls were scanned by micro-computed tomography and assessed using traditional and geometric morphometrics. Mandibular bone apoptosis was further assessed by TUNEL staining. Conditional Wnt5a LOF resulted in midface hypoplasia, increased maxillary intermolar width, increased rostral basisphenoid width, and delayed molar eruption. Wnt5a LOF mandibles did not have altered bone mineral density or bone microarchitecture unlike our previous study examining Wnt5a LOF femurs. In contrast, conditional Wnt5a GOF results in macrocephaly, shortened hard palate, increased zygomatic length, micrognathia, and mandibular process dysmorphology. The micrognathia and mandibular process dysmorphology in the Wnt5a GOF mice were not due to increased apoptosis. A partially penetrant snout deviation was present in both the Wnt5a LOF and GOF mice. Craniofacial and dental phenotype differed between mice with conditional GOF and LOF of Wnt5a, consistent with the craniofacial phenotype heterogeneity in WNT5A-associated Robinow syndrome. We detected tooth eruption delay, mandibular condyle dysmorphology, and facial asymmetry in mice with altered Wnt5a that have not been previously reported in patients with WNT5A-associated Robinow syndrome. Our data suggest precise regulation of Wnt5a is essential for proper craniofacial and dental development. Robinow syndrome is a rare disease that affects skull and facial bones. It is linked to changes in a gene called Wnt5a. To better understand how disruption of Wnt5a affects bone, researchers studied mice with either increased or decreased Wnt5a in bone cells. These mice showed a range of facial and dental anomalies, including changes in jaw and skull shape and tooth eruption timing. Some changes resembled those seen in people with Robinow syndrome, while others were new findings. This research shows that careful control of Wnt5a is crucial for the development of the face.

Bone fractures represent common traumatic injuries associated with significant morbidity due to acute and, in some cases, persistent chronic pain. Emerging evidence suggests the gut microbiota plays a critical role in modulating inflammatory and nociceptive signaling; however, its potential as a therapeutic target for alleviating fracture‐related pain remains largely unexplored. In this study, we examined the effects of probiotic supplementation with Bifidobacterium longum ( B. longum ) or Lacticaseibacillus casei ( L. casei ) on pain‐related behaviors, functional recovery, and systemic metabolic changes after unilateral femoral fracture in female C57BL/6J mice. While probiotic supplementation did not significantly alter body composition or whole‐body bone mineral density, B. longum supplementation resulted in a modest but significant increase in lumbar spine bone mineral density. Both probiotic strains significantly attenuated pain behaviors compared to vehicle‐treated controls, with B. longum demonstrating more rapid and pronounced analgesic effects, including improved hindlimb gait symmetry and reduced compensatory limb usage. Untargeted metabolomic analysis revealed strain‐specific and time‐dependent changes in systemic metabolic profiles, notably affecting pathways involved in neurotransmitter biosynthesis, tryptophan metabolism, and inflammatory signaling. Collectively, these findings highlight the therapeutic potential of microbiota‐targeted strategies as nonpharmacological interventions for improving functional recovery and reducing pain behavior following traumatic bone injury.

Over the past decade, significant attention has been directed toward understanding the role of the gut microbiome in health and disease. The gut microbiota, comprising a complex and diverse community of microorganisms, has been linked to numerous conditions, including metabolic disorders, gastrointestinal diseases, and inflammatory or autoimmune conditions. Recently, a growing body of evidence has revealed a compelling relationship between gut microbiota composition and musculoskeletal injury recovery, highlighting its potential as a novel therapeutic target. Musculoskeletal injuries, including fractures, post-traumatic osteoarthritis, and tendon or ligament injuries, commonly lead to changes in the community structure of the gut microbiota, intestinal permeability, and systemic inflammation, processes known to negatively influence tissue repair. Preclinical studies demonstrate that microbiota-targeted interventions, such as probiotics, prebiotics, and fecal microbiota transplantation, effectively restore gut barrier integrity, modulate inflammation, and normalize gut-derived metabolite profiles. Despite these promising findings, critical gaps remain in translating these effects into clinical practice, particularly regarding the mechanisms linking specific microbiota changes to improved musculoskeletal healing outcomes. Future research incorporating rigorous clinical trials, multi-omics analyses, and advanced predictive tools, including artificial intelligence and microbiome-informed digital twins, is urgently needed to fully harness the therapeutic potential of microbiome-based interventions in musculoskeletal injury recovery. This narrative review provides insights into our evolving understanding of the relationship between the gut microbiota and musculoskeletal injury and explores the potential of gut microbiota-targeted therapies for improved healing outcomes.

Introduction: Robinow syndrome has characteristic craniofacial and dental features and can be caused by gain- or loss-of-function variants in Wnt family member 5A ( WNT5A ) non-canonical signaling. The craniofacial and dental manifestation of Robinow syndrome is heterogenous, as is the effect of altered Wnt5a in animal models. The relationship between Wnt5a and craniofacial and dental phenotypes is not fully understood. Methods: To investigate the role of Wnt5a in craniofacial and dental development, we utilized a Wnt5a conditional loss-of-function (LOF: Wnt5a ^fl/fl ;Ctsk ^cre ) and a Wnt5a conditional gain-of-function (GOF: Rosa26-LSL-Wnt5a;Ctsk ^cre ) model to determine the effect of both LOF and GOF of Wnt5a in bone cells during craniofacial and dental development. Postnatal day 10 conditional LOF Wnt5a , GOF Wnt5a , and control skulls were scanned by micro-computed tomography and assessed using traditional and geometric morphometrics. Mandibular bone apoptosis was further assessed by TUNEL staining. Results: Conditional Wnt5a LOF resulted in midface hypoplasia, increased maxillary intermolar width, increased rostral basisphenoid width, and delayed molar eruption. Wnt5a LOF mandibles did not have altered bone mineral density or bone microarchitecture unlike our previous study examining Wnt5a LOF femurs. In contrast, conditional Wnt5a GOF results in macrocephaly, shortened hard palate, increased zygomatic length, micrognathia, and mandibular process morphology changes. The micrognathia and mandibular process morphology changes in the Wnt5a GOF mice were not due to increased apoptosis. A partially penetrant snout deviation was present in both the Wnt5a LOF and GOF mice. Conclusions: Craniofacial and dental phenotype differed between mice with conditional GOF and LOF of Wnt5a , consistent with the craniofacial phenotype heterogeneity in Wnt5a -associated Robinow syndrome. We detected tooth eruption delay, mandibular condyle dysmorphology, and facial asymmetry in mice with altered Wnt5a that have not been previously reported in patients. Our data suggest precise regulation of Wnt5a is essential for proper craniofacial and dental development.

Background: Celiac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten, affecting approximately 1% of the global population and two million Americans. An increasing number of studies have identified a link between celiac disease and adverse maternal and fetal outcomes during pregnancy and after birth. Additionally, both celiac disease and pregnancy are associated with an increased risk for nutrient deficiencies, specifically vitamin B12 and folate. Methods: This review examines the current literature related to the folate trap and vitamin B12 deficiency in patients with celiac disease and pregnant women independently and provides rationale for future research to explore the relationship between the folate-to-12 ratio in pregnant women with celiac disease. Results: Deficiencies in vitamin B12 are linked with several negative maternal and fetal health outcomes including pre-eclampsia, gestational diabetes, spontaneous abortion/miscarriage, preterm birth, neural tube defects, intrauterine growth restriction, and low gestational age and birthweight. Conclusions: Folic acid supplementation is widely recommended during pregnancy, but complementary vitamin B12 supplementation is not standard. Physicians should consider celiac disease screening during pregnancy as well as vitamin B12 supplementation.

Celiac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten, affecting approximately 1% of the global population and two million Americans. An increasing number of studies have identified a link between celiac disease and adverse maternal and fetal outcomes during pregnancy and after birth. Additionally, both celiac disease and pregnancy are associated with an increased risk for nutrient deficiencies, specifically vitamin B12 and folate. Deficiencies in these key nutrients are linked with several negative maternal and fetal health outcomes including preeclampsia, gestational diabetes, spontaneous abortion/miscarriage, preterm birth, NTDs, Intrauterine Growth Restriction, and low gestational age and birthweight. This review examines the current literature related to the folate trap and vitamin B12 deficiency in patients with celiac disease and pregnant women independently, and to provide rationale for future research to explore the correlation between the folate to B12 ratio in pregnant woman with celiac disease.

Fracture healing is a complex series of events that requires a local inflammatory reaction to initiate the reparative process. This inflammatory reaction is important for stimulating the migration and proliferation of mesenchymal progenitor cells from the periosteum and surrounding tissues to form the cartilaginous and bony calluses. The proinflammatory cytokine interleukin (IL)-17 family has gained attention for its potential regenerative effects; however, the requirement of IL-17 signaling within mesenchymal progenitor cells for normal secondary fracture healing remains unknown. The conditional knockout of IL-17 receptor a (Il17ra) in mesenchymal progenitor cells was achieved by crossing Il17ra^F/F mice with Prx1-cre mice to generate Prx1-cre; Il17ra^F/F mice. At 3 months of age, mice underwent experimental unilateral mid-diaphyseal femoral fractures and healing was assessed by micro-computed tomography (µCT) and histomorphometric analyses. The effects of IL-17RA signaling on the osteogenic differentiation of fracture-activated periosteal cells was investigated in vitro. Examination of the intact skeleton revealed that the conditional knockout of Il17ra decreased the femoral cortical porosity but did not affect any femoral trabecular microarchitectural indices. After unilateral femoral fractures, Il17ra conditional knockout impacted the cartilage and bone composition of the fracture callus that was most evident early in the healing process (day 7 and 14 post-fracture). Furthermore, the in vitro treatment of fracture-activated periosteal cells with IL-17A inhibited osteogenesis. This study suggests that IL-17RA signaling within Prx1+ mesenchymal progenitor cells can influence the early stages of endochondral ossification during fracture healing.