A systematic review of double-bundle versus single-bundle posterior cruciate ligament reconstruction.

BACKGROUND: Posterior Cruciate Ligament (PCL) ruptures are common sports injuries. One of the key controversies in PCL reconstruction is whether double-bundle reconstruction provides biomechanical and clinical outcomes superior to single-bundle reconstruction. METHODS: We performed a comprehensive search in multiple databases to evaluate the advantages of single-bundle or double bundle reconstructions in anteroposterior stability, graft tension, rotational stability, and functional outcome. RESULTS: Biomechanical comparisons evaluating anteroposterior stability described either no difference or increased stability in double-bundle reconstructions. Comparing these results is complicated by different graft choices, tensioning techniques, and tunnel positions. Biomechanical studies of graft tension demonstrated conflicting results regarding the optimal reconstruction technique. Seven retrospective clinical studies of single- and double-bundle reconstructions with methodological limitations reported no difference in clinical outcome. CONCLUSIONS: The superiority of single-bundle or double-bundle posterior cruciate ligament reconstruction remains uncertain.

Application strategy of finite element analysis in artificial knee arthroplasty.

Artificial knee arthroplasty, as the most effective method for the treatment of end-stage joint diseases such as knee osteoarthritis and rheumatoid arthritis, is widely used in the field of joint surgery. At present, Finite element analysis (FEA) has been widely used in artificial knee replacement biomechanical research. This review presents the current hotspots for the application of FEA in the field of artificial knee replacement by reviewing the existing research literature and, by comparison, summarizes guidance and recommendations for artificial knee replacement surgery. We believe that lower contact stress can produce less wear and complications when components move against each other, in the process of total knee arthroplasty (TKA), mobile-bearing prostheses reduce the contact surface stress of the tibial-femoral joint compared with fixed-bearing prostheses, thus reducing the wear of the polyethylene insert. Compared with mechanical alignment, kinematic alignment reduces the maximum stress and maximum strain of the femoral component and polyethylene insert in TKA, and the lower stress reduces the wear of the joint contact surface and prolongs the life of the prosthesis. In the unicompartmental knee arthroplasty (UKA), the femoral and tibial components of mobile-bearing prostheses have better conformity, which can reduce the wear of the components, while local stress concentration caused by excessive overconformity of fixed-bearing prostheses should be avoided in UKA to prevent accelerated wear of the components, the mobile-bearing prosthesis maintained in the coronal position from 4° varus to 4° valgus and the fixed-bearing prosthesis implanted in the neutral position (0°) are recommended. In revision total knee arthroplasty (RTKA), the stem implant design should maintain the best balance between preserving bone and reducing stress around the prosthesis after implantation. Compared with cemented stems, cementless press-fit femoral stems show higher fretting, for tibial plateau bone defects, porous metal blocks are more effective in stress dispersion. Finally, compared with traditional mechanical research methods, FEA methods can yield relatively accurate simulations, which could compensate for the deficiencies of traditional mechanics in knee joint research. Thus, FEA has great potential for applications in the field of medicine.

[Effect of fascia iliaca compartment block on anterolateral small incision total hip arthroplasty].

OBJECTIVE: To compare the effects of simple intraspinal anesthesia and combined fascia iliaca compartment block(FICB) on total hip arthroplasty(THA) through anterior lateral small incision (orthop dische chirurgie München, OCM). METHODS: From January 2019 to October 2020, patients undergoing unilateral total hip arthroplasty were treated with intraspinal anesthesia combined with ultrasound-guided fascia iliaca compartment block(30 cases in group A) and simple intraspinal anesthesia(30 cases in group B). Two groups were treated with the same intravenous analgesia after operation. The operation time, the amount of bleeding, the peeling degree of middle gluteal muscle, the splitting of greater trochanter of femur, the visual analysis scale (VAS) of hip joint after operation, the abductor muscle strength of quadriceps femoris and hip joint before and 48 hours after operation, and the Harris score of hip joint function after operation were observed and compared between two groups. RESULTS: All patients were followed up for 48 to 62 weeks with an average of (54.2±4.0) weeks. The incision length, operation time and intraoperative bleeding in group A were significantly lower than those in group B (P<0.05). The level of hemoglobin 24 hours after operation in group A was significantly higher than that in group B (P<0.05). The abductor muscle strength of hip joint in group A was significantly higher than that in group B 48 hours after operation (P<0.05). The degree of middle gluteal muscle dissection in group A was significantly lower than that in group B (P<0.05). The VAS of group A at 8, 12 and 24 hours after operation was significantly lower than that of group B (P<0.05);The Harris score in group A was significantly higher than that in group B at 2 and 8 weeks after operation (P<0.05). CONCLUSION: The application of ultrasound-guided fascia iliaca compartment block in lateral position OCM approach THA can significantly shorten the operation time, reduce the amount of bleeding, reduce the perihip trauma such as the peeling of middle gluteal muscle during operation, and improve the early postoperative pain of patients, which is conducive to the clinical operation of OCM approach and the rapid postoperative recovery of patients.

The Effects of Lateral Meniscus Posterior Root Tear and its Repair on Knee Stability of Internal Rotation and Forward Shift: A Biomechanical Kinematics Cadaver Study.

Objective: Lateral meniscal posterior root (LMPR) is an important stabilizer for knee joint, providing the stability during tibia forward shifting and internal rotating. It is still controversial that whether the LMPR tear (LMPRT) should be repaired together with ACL reconstruction. This study aims to investigate the effects of LMPR on knee stability with intact ACL. Methods: Eight cadaver knees were used and performed the biomechanical kinematics tests in orders of: Group A: the LMPR was intact; Group B: the LMPR was cut off from its tibial end; Group C: the LMPRT has been repaired. 1) An internal rotation moment (5 Nm) was given to the tibia, then the internal rotation angle of the tibia was measured; 2) An forward shifting force (134 N) was given to the tibia, then the anterior displacement of the tibia was measured; 3) An internal rotation moment (5 Nm) and a valgus moment (10 Nm) were given to the tibia, then the internal rotation angle and the anterior displacement was measured. The stability was inferred from smaller rotation angle and displacement, and all of the angles and displacements were measured at knee flexion of 0°, 30°, 60° and 90°, respectively. Results: Comparing to Group A, the internal rotation angle in Group B was increased significantly at knee flexion of 30° (p = 0.025), 60° (p = 0.041), 90° (p = 0.002); the anterior tibia displacement in Group B was increased significantly at knee flexion of 30° (p = 0.015), 60° (p = 0.024); at knee valgus, the internal rotation angle was also increased significantly at knee flexion of 60° (p = 0.011), 90° (p = 0.037). Comparing to Group B, the internal rotation angle in Group C was decreased significantly at knee flexion of 30° (p = 0.030), 60° (p = 0.019), 90° (p = 0.021); the anterior displacement in Group C was decreased significantly at knee flexion of 30° (p = 0.042), 60° (p = 0.037); at valgus, the internal rotation angle was also decreased significantly at knee flexion of 60° (p = 0.013), 90° (p = 0.045). Comparing to Group A, only the internal rotation angle (p = 0.047) and anterior displacement (p = 0.033) in Group C were increased at knee flexion of 30°. Conclusion: In simulated knee with intact ACL, LMPRT can still lead to the notable internal rotational instability at knee flexion from 30° to 90°, as well as the anterior shift instability at knee flexion from 30° to 60°. LMPRT repair help to improve the internal rotation stability at 30° and restore it at 60° to 90°, and improve the anterior shift stability at 30° and restore it at 60°.

The effects of different repair methods for a posterior root tear of the lateral meniscus on the biomechanics of the knee: a finite element analysis.

PURPOSE: To explore the impact of different repair methods for a lateral meniscus posterior root tear on the biomechanics of the knee joint using finite element analysis. METHODS: Finite element models of a healthy knee were established on the basis of MRI data from a volunteer using Mimics software, and the validity of the models was tested. The changes in the contact mechanics and kinematics of these finite element models under different repair approaches were then analyzed and compared. RESULTS: The normal meniscus had the maximum joint contact area, the minimum contact pressure, and the minimum contact stress. When total meniscectomy of the lateral meniscus was performed, the lateral compartment had the minimum joint contact area, the maximum contact pressure and the maximum contact stress. When complete avulsions of the posterior root of the lateral meniscus occurred, the maximum values of contact pressure and contact stress were between those of an intact meniscus and those of a meniscus treated with total meniscectomy. Lateral meniscal root attachment reconstruction by the single-stitch and double-stitch techniques resulted in a significant decrease in joint contact pressure and contact stress, leading to values comparable to those of a normal knee joint, and the double-stitch technique performed better than the single-stitch technique. CONCLUSIONS: Repair surgery for lateral meniscal posterior root avulsions can effectively restore the contact mechanics and kinematics of the knee joint, and the double-stitch technique can result in better clinical outcomes than the single-stitch technique.

The Radiated Deep-frozen Xenogenic Meniscal Tissue Regenerated the Total Meniscus with Chondroprotection.

Meniscal allograft transplantation yields good and excellent results but is limited by donor availability. The purpose of the study was to evaluate the effectiveness of radiated deep-frozen xenogenic meniscal tissue (RDF-X) as an alternative graft choice in meniscal transplantation. The xenogenic meniscal tissues were harvested from the inner 1/3 part of the porcine meniscus and then irradiated and deeply frozen. The medial menisci of rabbits were replaced by the RDF-X. Meniscal allograft transplantation, meniscectomy and sham operation served as controls. Only a particular kind of rabbit-anti-pig antibody (molecular ranging 60-80 kD) was detected in the blood serum at week 2. The menisci of the group RDF-X grossly resembled the native tissue and the allograft meniscus with fibrocartilage regeneration at postoperative 1 year. Cell incorporation and the extracellular matrix were mostly observed at the surface and the inner 1/3 part of the newly regenerated RDF-X, which was different from the allograft. The biomechanical properties of the group RDF-X were also approximate to those of the native meniscus except for the compressive creep. In addition, chondroprotection was achieved after the RDF-X transplantation although the joint degeneration was not completely prevented. To conclude, the RDF-X could be a promising alternative for meniscal transplantation with similar tissue regeneration capacity to allograft transplantation and superior chondroprotection. The potential minor immunological rejection should be further studied before its clinical application.

3D-Printed Poly(ε-caprolactone) Scaffold Augmented With Mesenchymal Stem Cells for Total Meniscal Substitution: A 12- and 24-Week Animal Study in a Rabbit Model.

BACKGROUND: Total meniscectomy leads to knee osteoarthritis in the long term. The poly(ε-caprolactone) (PCL) scaffold is a promising material for meniscal tissue regeneration, but cell-free scaffolds result in relatively poor tissue regeneration and lead to joint degeneration. HYPOTHESIS: A novel, 3-dimensional (3D)-printed PCL scaffold augmented with mesenchymal stem cells (MSCs) would offer benefits in meniscal regeneration and cartilage protection. STUDY DESIGN: Controlled laboratory study. METHODS: PCL meniscal scaffolds were 3D printed and seeded with bone marrow-derived MSCs. Seventy-two New Zealand White rabbits were included and were divided into 4 groups: cell-seeded scaffold, cell-free scaffold, sham operation, and total meniscectomy alone. The regeneration of the implanted tissue and the degeneration of articular cartilage were assessed by gross and microscopic (histological and scanning electron microscope) analysis at 12 and 24 weeks postoperatively. The mechanical properties of implants were also evaluated (tensile and compressive testing). RESULTS: Compared with the cell-free group, the cell-seeded scaffold showed notably better gross appearance, with a shiny white color and a smooth surface. Fibrochondrocytes with extracellular collagen type I, II, and III and proteoglycans were found in both seeded and cell-free scaffold implants at 12 and 24 weeks, while the results were significantly better for the cell-seeded group at week 24. Furthermore, the cell-seeded group presented notably lower cartilage degeneration in both femur and tibia compared with the cell-free or meniscectomy group. Both the tensile and compressive properties of the implants in the cell-seeded group were significantly increased compared with those of the cell-free group. CONCLUSION: Seeding MSCs in the PCL scaffold increased its fibrocartilaginous tissue regeneration and mechanical strength, providing a functional replacement to protect articular cartilage from damage after total meniscectomy. CLINICAL RELEVANCE: The study suggests the potential of the novel 3D PCL scaffold augmented with MSCs as an alternative meniscal substitution, although this approach requires further improvement before being used in clinical practice.

The Chondrogenic Potential of Progenitor Cells Derived from Peripheral Blood: A Systematic Review.

An increasing number of studies have detected mesenchymal stromal cells (MSCs) and mesenchymal progenitor cells (MPCs) in the peripheral blood (PB). This study aimed to systematically review the possibility of using the PB as a source for chondrogenic progenitors. PubMed, the Web of Science, and Embase were searched for relevant articles. The findings of the studies were reviewed to evaluate the biological characteristics of PB-derived MSCs, chondrogenic MPCs, and their applications in cartilage repair. Thirty-six articles were included in the final analysis, 29 of which indicated that PB is a potential source for chondrogenic progenitor cells. Thirty-two studies reporting in vitro data, including 79.2% (19/24) of studies on PB MSCs and 75% (6/8) of studies on chondrogenic PB MPCs, confirmed the existence of PB MSCs and PB MPCs, respectively; all in vivo investigations showed that using PB as a cell source enhanced cartilage repair. PB MSCs were found in most of the animal studies (12/13), whereas 7 of 11 human studies described the presence of PB MSCs. This systematic review strongly indicates the existence of MSCs in the PB of animals, whereas the presence of MSCs in human PB is less clear. Although the presence of both MSCs and chondrogenic MPCs in the PB, as well as a few favorable outcomes associated with the use of PB-derived progenitors for cartilage repair in vivo, suggests that the PB is a potential alternative source of chondrogenic progenitor cells for cartilage repair, the efficacy of these cells has not been compared to those from other sources, such as bone marrow or adipose tissue in controlled studies.

Chondrogenic Potential of Peripheral Blood Derived Mesenchymal Stem Cells Seeded on Demineralized Cancellous Bone Scaffolds.

As a cell source with large quantity and easy access, peripheral blood mesenchymal stem cells (PBMSCs) were isolated and seeded in porcine demineralized cancellous bone (DCB) scaffolds, cultured in chondrogenic medium and evaluated for in vitro chondrogenesis. Bone marrow MSCs (BMMSCs) and articular cartilage chondrocytes (ACCs) underwent the same process as controls. The morphology, viability and proliferation of PBMSCs in DCB scaffolds were similar to those of BMMSCs and ACCs. PBMSCs and BMMSCs showed similar chondrogenesis potential with consistent production of COL 2 and SOX 9 protein and increased COL 2 and AGC mRNA expressions at week 3 but the COL 2 protein production was still less than that of ACCs. Minimal increase of hypertrophic markers was found in all groups. Relatively higher ALP and lower COL 10 mRNA expressions were found in both MSCs groups at week 3 than that in ACCs, whereas no significant difference of COL 1 and SOX 9 mRNA and MMP 13 protein was found among all groups. To conclude, PBMSCs shared similar proliferation and chondrogenic potential with BMMSCs in DCB scaffolds and could be an alternative to BMMSCs for cartilage tissue engineering. Further optimization of chondrogenesis system is needed regardless of the promising results.

Role of scaffold mean pore size in meniscus regeneration.

UNLABELLED: Recently, meniscus tissue engineering offers a promising management for meniscus regeneration. Although rarely reported, the microarchitectures of scaffolds can deeply influence the behaviors of endogenous or exogenous stem/progenitor cells and subsequent tissue formation in meniscus tissue engineering. Herein, a series of three-dimensional (3D) poly(ε-caprolactone) (PCL) scaffolds with three distinct mean pore sizes (i.e., 215, 320, and 515µm) were fabricated via fused deposition modeling. The scaffold with the mean pore size of 215µm significantly improved both the proliferation and extracellular matrix (ECM) production/deposition of mesenchymal stem cells compared to all other groups in vitro. Moreover, scaffolds with mean pore size of 215µm exhibited the greatest tensile and compressive moduli in all the acellular and cellular studies. In addition, the relatively better results of fibrocartilaginous tissue formation and chondroprotection were observed in the 215µm scaffold group after substituting the rabbit medial meniscectomy for 12weeks. Overall, the mean pore size of 3D-printed PCL scaffold could affect cell behavior, ECM production, biomechanics, and repair effect significantly. The PCL scaffold with mean pore size of 215µm presented superior results both in vitro and in vivo, which could be an alternative for meniscus tissue engineering. STATEMENT OF SIGNIFICANCE: Meniscus tissue engineering provides a promising strategy for meniscus regeneration. In this regard, the microarchitectures (e.g., mean pore size) of scaffolds remarkably impact the behaviors of cells and subsequent tissue formation, which has been rarely reported. Herein, three three-dimensional poly(ε-caprolactone) scaffolds with different mean pore sizes (i.e., 215, 320, and 515µm) were fabricated via fused deposition modeling. The results suggested that the mean pore size significantly affected the behaviors of endogenous or exogenous stem/progenitor cells and subsequent tissue formation. This study furthers our understanding of the cell-scaffold interaction in meniscus tissue engineering, which provides unique insight into the design of meniscus scaffolds for future clinical application.

Novel customized template designing for patellar resurfacing in total knee arthroplasty.

Due to the irregular shape of patella and difficulty in identifying its bony landmarks, it can be a challenge for surgeons to accurately and symmetrically perform patellar resurfacing. Three-dimensional (3D) models of 20 patellae were generated from computed tomographic images. Using a computer-assisted preoperative planning technique, customized template designs were developed to guide patellar resurfacing. The patellar models and corresponding templates were produced through rapid prototyping. The accuracy of this technique was assessed after applying the templates on patellar models and cadaver specimens, respectively. Using preoperative planning and predesigned templates, a significant improvement in symmetric patellar resurfacing, with a mean angle of 1.21° mediolateral (ML) obliquity and 1.95° superoinferior (SI) obliquity, was observed compared with the conventional sawguide technique (mean angle of ML and SI was 4.13°, 4.95°, respectively). Additionally, the use of customized templates reproduced the desired preplanned patellar resection. Preoperative planning with 3D imaging and customized templates improved the accuracy of patellar resurfacing in terms of the obliquity and thickness. CLINICAL RELEVANCE: A novel customized template designed for patellar resectioning will benefit surgeons in performing patellar resurfacing. This technique will provide accurate patellar resurfacing in clinical practice. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1798-1803, 2016.

Thermogel-Coated Poly(ε-Caprolactone) Composite Scaffold for Enhanced Cartilage Tissue Engineering.

A three-dimensional (3D) composite scaffold was prepared for enhanced cartilage tissue engineering, which was composed of a poly(ε-caprolactone) (PCL) backbone network and a poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PLGA⁻PEG⁻PLGA) thermogel surface. The composite scaffold not only possessed adequate mechanical strength similar to native osteochondral tissue as a benefit of the PCL backbone, but also maintained cell-friendly microenvironment of the hydrogel. The PCL network with homogeneously-controlled pore size and total pore interconnectivity was fabricated by fused deposition modeling (FDM), and was impregnated into the PLGA⁻PEG⁻PLGA solution at low temperature (e.g., 4 °C). The PCL/Gel composite scaffold was obtained after gelation induced by incubation at body temperature (i.e., 37 °C). The composite scaffold showed a greater number of cell retention and proliferation in comparison to the PCL platform. In addition, the composite scaffold promoted the encapsulated mesenchymal stromal cells (MSCs) to differentiate chondrogenically with a greater amount of cartilage-specific matrix production compared to the PCL scaffold or thermogel. Therefore, the 3D PCL/Gel composite scaffold may exhibit great potential for in vivo cartilage regeneration.

Potential of centrifugal seeding method in improving cells distribution and proliferation on demineralized cancellous bone scaffolds for tissue-engineered meniscus.

Tissue-engineered meniscus offers a possible solution to the regeneration and replacement problem of meniscectomy. However, the nonuniform distribution and declined proliferation of seeded cells on scaffolds hinder the application of tissue-engineered meniscus as a new generation of meniscus graft. This study systematically investigated the performances of different seeding techniques by using the demineralized cancellous bone (DCB) as the scaffold. Static seeding, injection seeding, centrifugal seeding, and vacuum seeding methods were used to seed the meniscal fibrochondrocytes (MFCs) and mesenchymal stem cells (MSCs) to scaffolds. Cell-binding efficiency, survival rate, distribution ability, and long-term proliferation effects on scaffolds were quantitatively evaluated. Cell adhesion was compared via cell-binding kinetics. Cell viability and morphology were assessed by using fluorescence staining. Combined with the reconstructed three-dimensional image, the distribution of seeded cells was investigated. The Cell Counting Kit-8 assay and DNA assay were employed to assess cell proliferation. Cell-binding kinetics and cell survival of the MFCs were improved via centrifugal seeding compared to injection or vacuum seeding methods. Seeded MFCs by centrifugation showed a more homogeneous distribution throughout the scaffold than cells seeded by other methods. Moreover, the penetration depth in the scaffold of seeded MFCs by centrifugation was 300-500 µm, much higher than the value of 100-300 µm by the surface static and injection seeding. The long-term proliferation of the MFCs in the centrifugal group was also significantly higher than that in the other groups. The results of the MSCs were similar to those of the MFCs. The centrifugal seeding method could significantly improve MFCs or MSCs distribution and proliferation on the DCB scaffolds, thus providing a simple, cost-effective, and effective cell-seeding protocol for tissue-engineered meniscus.