Wear particle-induced periprosthetic inflammatory osteolysis and resultant aseptic loosening are major causes of orthopedic implant failure, for which there are no effective treatments other than revision surgery. Crocin, a carotenoid compound derived from crocus flowers, has anti-inflammatory properties, but its immunomodulatory function and role in particle-induced osteolysis are not well characterized. Here we report the effect of crocin on titanium (Ti) particle-induced macrophage polarization and osteogenic differentiation. We found that crocin induced anti-inflammatory (M2) macrophage polarization and attenuated Ti particle-induced inflammation by promoting the expression of anti-inflammatory cytokines in vitro as well as in vivo in a mouse air-pouch model. Additionally, crocin pre-treated macrophages promoted osteogenic differentiation of co-cultured mouse bone mesenchymal stem cells (BMSCs). These effects were mediated via inhibition of p38 and c-Jun N-terminal kinase signaling. Our results indicate that crocin suppresses Ti particle-induced inflammation and enhances osteogenic differentiation of BMSCs by inducing M2 macrophage polarization, highlighting its therapeutic potential for preventing wear particle-induced osteolysis.

Recent studies have indicated that the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is an ideal therapeutic target for osteoporosis because it affects the differentiation of osteoblasts and osteoclasts. RNA sequencing utilizing multifunctional graphene oxide (GO) nanosheets revealed a correlation between GO nanomaterials and the NLRP3 inflammasome, as well as osteogenic genes in macrophages. This study aimed to construct a bone microenvironment-responsive multifunctional two-dimensional GO coating on the surface of microporous sulfonated polyetheretherketone (SPEEK) via polydopamine modification (SPEEK@PDA-GO). In vitro analysis showed that the SPEEK@PDA-GO implants weakened the STAT3-mediated NLRP3/caspase-1/IL-1β signaling pathway in macrophages and subsequently prevented the formation of an extracellular inflammatory microenvironment, which is crucial for osteoclastogenesis. SPEEK@PDA-GO displayed significantly higher expression of M2 macrophage markers and osteogenic genes, indicating that the multifunctional GO nanosheets could facilitate bone regeneration via their immunomodulatory properties. The ability of SPEEK@PDA-GO to stimulate new bone formation and block bone loss caused by estrogen loss due to ovariectomy was also analyzed. The findings of this study offer valuable information on the possible involvement of the NLRP3 inflammasome in the interaction between the immune system and bone health in patients with osteoporosis.

Objective: In revision total hip arthroplasty (THA), reconstruction of severe acetabular bone defect continues to be problematic for orthopedic surgeons. This study reports the mid‐ to long‐term survivorship, radiological outcomes, and complications of impaction bone grafting (IBG) and metal mesh with a cemented acetabular component in the reconstruction of severe acetabular bone defects in revision THA.Methods: This retrospective consecutive study included 26 patients (29 hips: type II B, four; type II C, three; type III A, 10; and type III B, 12) who underwent revision THA, which was performed using IBG and metal mesh, between 2007 and 2014 in our institution. All patients were followed up regularly for clinical and radiographical assessments. Migration and loosening of prosthesis graft integration and complications were observed and analyzed. Survival analysis was performed using a Kaplan–Meier survival analysis.Results: At the time of revision, 75.9% of the hips (22 hips) were classified as type III bone defects. The average follow‐up period was 9.4 ± 2.8 (range, 2.4–14.0) years. Of the 29 hips, four hips (13.8%) were assessed as clinical failures; at the last follow‐up, two had undergone re‐revision THA, and two had not been scheduled for re‐revision THA despite radiological failure of the acetabular component. Among them, three clinical failures (10.3%) were due to aseptic loosening, and one (3.4%) was due to infection. Radiographic evaluation showed bone graft integration in all hips during the follow‐up. The Kaplan–Meier survivorship analysis revealed an acetabular reconstruction survival rate of 86.5% (95% confidence interval, 61.4%–95.7%) at 10 years.Conclusion: IBG and metal mesh with a cemented acetabular component for revision THA is an effective technique for treating severe acetabular bone defects, with effective mid‐ to long‐term outcomes due to the solid reconstruction of the acetabular bone defect and restoration of the hip rotation center.

Objective: Retention or sacrifice of the posterior cruciate ligament (PCL) is one of the most controversial issues while performing total knee arthroplasty (TKA). This study aimed to evaluate the impact of PCL resection on flexion–extension gaps, femoral component rotation, and bone resection amounts during robot‐assisted TKA.Methods: This prospective study included 40 patients with knee osteoarthritis who underwent robot‐assisted posterior‐stabilized (PS) TKA between September 2021 and February 2022. Of the patients, 75% were women (30/40) with a mean age and BMI of 72.6 years and 27.4 kg/m², respectively. The guidance module and camera stand assembly were used to capture gaps before and after PCL resection. Measurements of femoral component rotation and bone resection amounts were made in cruciate‐retaining (CR) TKA mode and PS‐TKA mode.Results: After PCL resection, the mean change in the medial and lateral compartments of flexion gaps increased by 2.0 and 0.6 mm, respectively (p < 0.001). Compared with the CR‐TKA mode group, the bone resection amounts of the medial posterior condyle and the lateral posterior condyle in the PS‐TKA mode group decreased by 2.0 ± 1.1 and 1.1 ± 1.1 mm, respectively, and the external rotation of the femoral prosthesis relative to the posterior condylar axis and trans‐epicondylar line was reduced by 1.0° ± 1.3° and 1.2° ± 1.6°, respectively (p < 0.001).Conclusion: The release of the PCL did not affect the extension gap, but significantly increased the flexion gap. Moreover, the increases in the medial flexion gap were greater than those of the lateral flexion gap. After PCL resection, less external rotation of the femoral prosthesis and fewer bone cuts of the posterior femur were needed in PS‐TKA.

Avascular necrosis of the femoral head (ANFH) is a debilitating bone disease, characterized by collapse of the femoral head and subsequent loss of hip joint function. Heterozygous mutations in COL2A1 have been identified to cause familial ANFH. Here we report on a large Chinese family with ANFH and a novel heterozygous mutation (c.3517 G > A, p.Gly1173Ser) in exon 50 of COL2A1 in the Gly-X–Y domain. Previously, only five different COL2A1 mutations have been described in patients with familial ANFH. Therefore, our findings provide significant clues to the phenotype–genotype relationships in familial ANFH and may be helpful in clinical diagnosis. Furthermore, these results should assist further studies of the mechanisms underlying collagen diseases.

Avascular necrosis of the femoral head (ANFH) is a debilitating bone disease, characterized by collapse of the femoral head and subsequent loss of hip joint function. Heterozygous mutations in COL2A1 have been identified to cause familiar ANFH. Here we report on a large Chinese family with ANFH and a novel heterozygous mutation (c.3517 G > A, Gly1173Ser) in exon 50 of COL2A1 in the Gly-X-Y domain. Previously, only five different COL2A1 mutations have been described in patients familiar ANFH. Therefore, our findings provide significant clues to the phenotype-genotype relationships in familiar ANFH and may be helpful in clinical diagnosis. Furthermore, these results should assist further studies of the mechanisms underlying collagen diseases.