Osteoporosis is a degenerative disease characterized by decreased bone mass and destruction of bone microstructure. At present, previous studies have found that the structure and content of type Ⅰ collagen fibers are closely related to osteoporosis. However, there have been few studies on the prevention and treatment of osteoporosis using type Ⅰ collagen fibers as therapeutic targets. In this paper, the relationships between type Ⅰ collagen fibers and osteoporosis, biomechanics, bone matrix and bone strength are discussed. At the same time, the regulation of type Ⅰ collagen-related signaling pathways in osteoporosis is summarized, such as the signaling pathways of cathepsin K, transforming growth factor-β/Sma- and Mad-related protein, transforming growth factor-β/bone morphogenetic protein, c-jun N-terminal protein kinase and Wnt/β-catenin, in order to provide a new therapeutic direction for the prevention and treatment of osteoporosis.
ObjectiveTo summarize research progress of change in bone mineral density (BMD) after knee arthroplasty and its diagnostic methods, influencing factors, and drug prevention and treatment.MethodsThe relevant literature at home and abroad was reviewed and summarized from research status of the advantages and disadvantages of BMD assessment methods, the trend of changes in BMD after knee arthroplasty and its influencing factors, and the differences in effectiveness of drugs.ResultsThe central BMD and mean BMD around the prosthesis decrease after knee arthroplasty, which is closely associated with body position, age, weight, daily activities, and the fixation methods, design, and material of prosthesis. Denosumab, bisphosphonates, and teriparatide et al. can decrease BMD loss after knee arthroplasty.ConclusionBMD after knee arthroplasty decreases, which is related to various factors, but the mechanism is unclear. At present, some inhibitors of bone resorption can decrease BMD loss after knee arthroplasty. However, its long-term efficacy remains to be further explored.
ObjectiveTo investigate biomechanical effects of pseudo-patella baja on stress of patellofemoral joint after total knee arthroplasty (TKA) by using finite element analysis (FEA).MethodsA series of CT and MRI of the left knee joint of two healthy volunteers and three-dimensional (3D) scanned data of TKA prosthesis were taken, and the 3D models of knee before and after TKA were established. The finite element model of pseudo-patella baja, normal patella, and alta patella after TKA were constructed by Insall-Salvafi (IS) ratio and Blackburne-Peel (BP) ratio. The load was applied along the direction of quadriceps femoris. After testing the validity of the finite element model, the high contact stress of patellofemoral joint was measured on the von Mise stress nephogram of pseudo-patella baja, normal patella, and alta patella after TKA when the knee flexion was 30°, 60°, and 90°. The average contact area was calculated according to two volunteers’ data.ResultsOn the finite element model of the normal patella after TKA with knee flexion 30°, 475 N pressure was applied along the direction of quadriceps femoris. The contact stress of patellofemoral joint was (1.29±0.41) MPa, which was similar to the results reported previously. The finite element model was valid. The von Mise stress nephogram showed that the stress mainly focused on the medial patellofemoral articular surface during knee flexion, and the contact point gradually moved up with the knee flexion deepened. The stress on the medial and lateral patellofemoral articular surface increased with the knee flexion deepened but decreased with the increase of patellar height. The effects of patellar height and knee flexion on the high contact stress of patellofemoral joint were similar among the finite element models after TKA based on the data of two volunteers. The high contact stress of patellofemoral joint increased with the knee flexion deepened in the same patellar height models (P<0.05), but decreased with the increase of patellar height in the same knee flexion models (P<0.05). The high contact stress of patellofemoral joint of pseudo-patella baja model was significantly higher than normal and alta patella models (P<0.05). The average contact area of patellofemoral joint of pseudo-patella baja was bigger than normal and alta patella models with the knee flexion deepened.ConclusionThe pseudo-patella baja after TKA has an important effect on the biomechanics of patellofemoral joint. Reserving the joint line and avoiding the occurrence of pseudo-patella baja can decrease the risk of anterior knee pain, patellar arthritis, and other complications caused by the increasing of contact stress of patellofemoral joint.
ObjectiveTo review the research progress on finite element analysis (FEA) of unicompartmental knee arthroplasty (UKA) in medial knee compartmental osteoarthritis.MethodsThe FEA research literature on the medial knee UKA at home and abroad was reviewed, and the progress on the aspects of the influences of the prosthesis arrangement and the postoperative joint line on the mechanical distribution of the knee joint, the improvement of the UKA prosthesis, and the related research of different types of prostheses were summarized.ResultsAt present, scholars have conducted a large number of FEA studies on UKA in the medial knee compartmental osteoarthritis. The results of the study show that the recommended coronal alignment and the tibial slope angle of tibial component in medial fixed-bearing UKA are 0° and 5°-7°, respectively; and the coronal alignment and the tibial slope angle of tibial component in mobile-bearing UKA are 4° varus to 4° valgus and 5°-7°, respectively. The femoral component is arranged in the neutral position of the distal femur. The joint line is recommended to be the primary alignment. The anatomical UKA prosthesis can restore the biomechanical properties of the normal knee joint.ConclusionFEA research can clarify the best arrangement and joint line of the medial knee UKA prosthesis based on the mechanical distribution results, and guide the design of UKA prostheses that are more suitable for patients.
ObjectiveTo study the expressions of Renin, angiotensin converting enzyme (ACE), angiotensin receptor 1 (AT1R), and AT2R in synovial tissue of osteoarthritis (OA) at different stages.MethodsThe patients who were treated with upper knee amputation because of trauma or total knee arthroplasty for OA between January 2018 and December 2018 were enrolled. Among them, 32 patients who met the selection criteria were included in the study. According to the Kellgren-Lawrence (K-L) X-ray classification, they were allocated to normal synovial group (group A, n=9), moderate OA synovial group (group B, n=11, K-L level 3), and advanced OA synovial group (group C, n=12, K-L level 4). The relative expressions of Renin, ACE, AT1R, and AT2R mRNAs and proteins were detected by real-time fluorescence quantitative PCR (qRT-PCR) and Western blot.ResultsThe relative expressions of Renin, ACE, and AT1R mRNAs and proteins were significantly higher in group B and group C than in group A (P<0.05). The relative expressions of ACE and AT1R mRNAs and proteins and Renin protein were significantly higher in group C than in group B (P<0.05). However, the relative expressions of AT2R mRNA and protein were lower in group B and group C than in group A (P<0.05), and in group C than in group B (P<0.05).ConclusionThe expressions of Renin, ACE, and AT1R in synovial tissue of osteoarthritis significantly increase as the K-L level increased, and the expression of AT2R decreases. Renin, ACE, AT1R, and AT2R have a certain degree of correlation with the development of OA.
ObjectiveTo summarize research progress of the effect of knee flexion position on postoperative blood loss and knee range of motion (ROM) after total knee arthroplasty (TKA).MethodsThe relevant literature at home and abroad was reviewed and summarized from mechanism, research status, progress, and clinical outcome. The differences of clinical results caused by different positions, flexion angles, and keeping time were compared.ResultsKeeping knee flexion after TKA can reduce postoperative blood loss through the angle change of blood vessels and increase knee early ROM by improving flexion muscle strength. When the flexion angle of the knee is large and the flexion position is keeping for a long time, the postoperative blood loss and the knee ROM can be significantly improved. However, the amount of blood loss and ROM are not further improved in the patients with keeping knee flexion for more than 24 hours compared with less than 24 hours.ConclusionKeeping knee flexion after TKA is a simple and effective method to reduce postoperative blood loss and improve knee ROM. However, the optimal knee flexion angle and time are needed to be further explored.
Objective To evaluate early to medium-term effectiveness of total hip arthroplasty (THA) in patients with a history of hip preservation surgery with secondary severe osteoarthritis for developmental dysplasia of the hip (DDH). Methods The clinical data of 25 DDH patients (31 hips) who had severe osteoarthritis after hip preservation surgery and received THA between September 2009 and March 2021 were retrospectively analyzed. There were 1 male and 24 females; the age ranged from 18 to 65 years, with an average age of 43 years; 8 hips were classified into Crowe type Ⅰ, 9 hips were type Ⅱ, 3 hips were type Ⅲ, and 11 hips were type Ⅳ. The time between osteotomy and THA ranged from 31 to 51 years, with an average of 31.96 years. Preoperative hip flexion range of motion was (69.31±29.72)°, abduction range of motion was (24.00±14.79)°; and Harris hip score was 45.3±15.5. Postoperative Harris hip score, hip range of motion, complications, radiographic findings, and implant survival rate were analyzed. Results Patients in both groups were followed up 2-132 months, with an average of 51 months. During the follow-up, periprosthetic fracture occurred in 1 case; there was no complication such as dislocation, periprosthetic infection, nerve palsy, or deep vein thrombosis. At last follow-up, the hip flexion range of motion was (109.52±11.17)°, abduction range of motion was (41.25±5.59)°, showing significant differences when compared with preoperative values (t=8.260, P=0.000; t=6.524, P=0.000). The Harris hip score was 91.5±4.1, and the difference was significant when compared with preoperative score (t=11.696, P=0.000); among them, 13 cases were excellent and 12 cases were good. Radiographic evaluation showed that the center of acetabular rotation moved up 0-18 mm (mean, 6.35 mm). The cup abductor angle was 28°-49° (mean, 37.74°) and the coverage rate was 69.44%-98.33% (mean, 81.04%). All femoral stems were fixed in neutral position without varus or valgus. No osteolysis, radiolucent line, or implant migration was observed. By the end of follow-up, none of the patients underwent revision and the survival rate of prothesis was 100%. ConclusionTHA is still the gold standard for the treatment of DDH patients with secondary osteoarthritis after hip preservation surgery. The postoperative joint function can be rapidly restored, the patients’ quality of life can significantly improve, and the early to medium-term survival rate of the prosthesis is satisfactory.
Objective To review the research progress of mitochondrial dynamics mediated by optic atrophy 1 (OPA1) in skeletal system diseases. MethodsThe literatures about OPA1-mediated mitochondrial dynamics in recent years were reviewed, and the bioactive ingredients and drugs for the treatment of skeletal system diseases were summarized, which provided a new idea for the treatment of osteoarthritis. Results OPA1 is a key factor involved in mitochondrial dynamics and energetics and in maintaining the stability of the mitochondrial genome. Accumulating evidence indicates that OPA1-mediated mitochondrial dynamics plays an important role in the regulation of skeletal system diseases such as osteoarthritis, osteoporosis, and osteosarcoma. Conclusion OPA1-mediated mitochondrial dynamics provides an important theoretical basis for the prevention and treatment of skeletal system diseases.