Adipose-Derived Mesenchymal Stem Cells-Conditioned Medium Modulates the Expression of Inflammation Induced Bone Morphogenetic Protein-2, -5 and -6 as Well as Compared with Shockwave Therapy on Rat Knee Osteoarthritis

The dose-dependent effects of adipose-derived mesenchymal stem cell-conditioned medium (ADSC-CM) were compared with those of shockwave (SW) therapy in the treatment of early osteoarthritis (OA). Anterior cruciate ligament transaction (ACLT) with medial meniscectomy (MMx) was performed in rats divided into sham, OA, SW, CM1 (intra-articular injection of 100 μL ADSC-CM into knee OA), and CM2 (intra-articular injection of 200 μL ADSC-CM) groups. Cartilage grading, grading of synovium changes, and specific molecular analysis by immunohistochemistry staining were performed. The OARSI and synovitis scores of CM2 and SW group were significantly decreased compared with those of the OA group (p < 0.05). The inflammatory markers interleukin 1β, terminal deoxynucleotidyl transferase dUTP nick end labeling and matrix metalloproteinase 13 were significantly reduced in the CM2 group compared to those in the SW and CM1 groups (p < 0.001). Cartilage repair markers (type II collagen and SRY-box transcription factor 9, SOX9) expression were significantly higher in the CM2 group than in the other treatment groups (p < 0.001; p < 0.05). Furthermore, inflammation-induced growth factors such as bone morphogenetic protein 2 (BMP2), BMP5, and BMP6 were significantly reduced in the treatment groups, and the CM2 group showed the best results among the treatments (p < 0.05). In conclusion, ADSC-CM and SW ameliorated the expression of inflammatory cytokines and inflammation-induced BMPs to protect the articular cartilage of the OA joint.

Detection and Evaluation of Serological Biomarkers to Predict Osteoarthritis in Anterior Cruciate Ligament Transection Combined Medial Meniscectomy Rat Model

Biomarkers are essential tools in osteoarthritis (OA) research, clinical trials, and drug development. Detecting and evaluating biomarkers in OA research can open new avenues for researching and developing new therapeutics. In the present report, we have explored the serological detection of various osteoarthritis-related biomarkers in the preclinical model of OA. In this surgical OA model, we disrupted the medial tibial cartilage’s integrity via anterior cruciate ligament transection combined with medial meniscectomy (ACLT+MMx) of a single joint of Wistar rats. The progression of OA was verified, as shown by the microscopic deterioration of cartilage and the increasing cartilage degeneration scoring from 4 to 12 weeks postsurgery. The concentration of serological biomarkers was measured at two timepoints, along with the complete blood count and bone electrolytes, with biochemical analysis further conducted. The panel evaluated inflammatory biomarkers, bone/cartilage biomarkers, and lipid metabolic pathway biomarkers. In chronic OA rats, we found a significant reduction of total vitamin D3 and C-telopeptide fragments of type II (CTX-II) levels in the serum as compared to sham-operated rats. In contrast, the serological levels of adiponectin, leptin, and matrix metallopeptidase (MMP3) were significantly enhanced in chronic OA rats. The inflammatory markers, blood cell composition, and biochemical profile remained unchanged after surgery. In conclusion, we found that a preclinical model of single-joint OA with significant deterioration of the cartilage can lead to serological changes to the cartilage and metabolic-related biomarkers without alteration of the systemic blood and biochemical profile. Thus, this biomarker profile provides a new tool for diagnostic/therapeutic assessment in OA scientific research.

Ketogenic Diet Ameliorates Inflammation by Inhibiting the NLRP3 Inflammasome in Osteoarthritis

Background: The nucleotide oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome has been reported to be involved in the pathological process of osteoarthritis (OA) inflammation. The ketogenic diet (KD), which previously demonstrated to inhibit NLRP3 inflammasome activation, was evaluated to elucidate its protective mechanism against OA in rats. Methods: Anterior cruciate ligament transaction (ACLT) together with partial medial meniscectomy was used to create an OA model of rat knee joint. After treatment with KD or standard diet (SD) for 8 weeks, the knee specimens were obtained for testing. Results: KD significantly increased the content of β-hydroxybutyrate (βOHB) in rats. Compared with the SD group, KD significantly reduced the damage caused by OA in the articular cartilage and subchondral bone. NLRP3 inflammasome and inflammatory cytokines interleukin-1 β (IL-1 β) and IL-18 were significantly increased in the SD group compared with the Sham group, while their expressions were significantly decreased in rats treated with KD. In addition, MMP13 in the KD group was significantly decreased compared with that in the SD group, while COL2 was significantly increased. Conclusions: This study confirmed that KD can protect the articular cartilage and subchondral bone in a rat OA model, and its mechanism is that KD reduces the OA inflammatory response by inhibiting the activation of NLRP3 inflammasome.

Biomechanical Analysis of Segmental Medial Meniscal Transplantation in a Human Cadaveric Model

Background: Meniscal deficiency has been reported to increase contact pressures in the affected tibiofemoral joint, possibly leading to degenerative changes. Current surgical options include meniscal allograft transplantation and insertion of segmental meniscal scaffolds. Little is known about segmental meniscal allograft transplantation. Purpose: To evaluate the effectiveness of segmental medial meniscal allograft transplantation in the setting of partial medial meniscectomy in restoring native knee loading characteristics. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen human cadaveric knees underwent central midbody medial meniscectomy and subsequent segmental medial meniscal allograft transplantation. Knees were loaded in a dynamic tensile testing machine to 1000 N for 20 seconds at 0°, 30°, 60°, and 90° of flexion. Four conditions were tested: (1) intact medial meniscus, (2) deficient medial meniscus, (3) segmental medial meniscal transplant fixed with 7 meniscocapsular sutures, and (4) segmental medial meniscal transplant fixed with 7 meniscocapsular sutures and 1 suture fixed through 2 bone tunnels. Submeniscal medial and lateral pressure-mapping sensors assessed mean contact pressure, peak contact pressure, mean contact area, and pressure mapping. Two-factor random-intercepts linear mixed effects models compared pressure and contact area measurements among experimental conditions. Results: The meniscal-deficient state demonstrated a significantly higher mean contact pressure than all other testing conditions (mean difference, ≥0.35 MPa; P < .001 for all comparisons) and a significantly smaller total contact area as compared with all other testing conditions (mean difference, ≤140 mm2; P < .001 for all comparisons). There were no significant differences in mean contact pressure or total contact area among the intact, transplant, or transplant-with-tunnel groups or in any outcome measure across all comparisons in the lateral compartment. No significant differences existed in center of pressure and relative pressure distribution across testing conditions. Conclusion: Segmental medial meniscal allograft transplantation restored the medial compartment mean contact pressure and mean contact area to values measured in the intact medial compartment. Clinical Relevance: Segmental medial meniscal transplantation may provide an alternative to full meniscal transplantation by addressing only the deficient portion of the meniscus with transplanted tissue. Additional work is required to validate long-term fixation strength and biologic integration.

Kinematic Alterations After Anterior Cruciate Ligament Reconstruction via Transtibial Techniques With Medial Meniscal Repair Versus Partial Medial Meniscectomy

Background: The treatment strategies for meniscal injuries during anterior cruciate ligament (ACL) reconstruction remain a topic of debate. Hypothesis: After ACL reconstruction, knee kinematics would be affected by different medial meniscal treatment (partial medial meniscectomy [PMM] and medial meniscal repair [MMR]). Study Design: Controlled laboratory study. Methods: A total of 161 patients underwent primary single-bundle ACL reconstruction and simultaneous medial meniscal treatment. Of these, 32 patients were eligible to participate in the kinematic assessment at 24.8 ± 1.7 months after surgery. Patients were divided into 2 groups: (1) those who underwent MMR (Group MMR; n = 18) and (2) those who underwent PMM (Group PMM; n = 14). Twenty healthy participants (Group Intact) were recruited who were comparable in age, body mass index, and sex. The kinematic parameters were collected using an optical tracking system during treadmill gait. Range of motion and kinematic parameters at key events during the gait cycle were compared between the 3 groups. The primary outcomes were the differences in adduction/abduction and internal/external rotation. Results: Patients in Group PMM walked with increased adduction as compared with those in Group Intact during the early stance phase ( P = .003; η2 = 0.172) and midstance phase ( P = .003; η2 = 0.167). In terms of internal/external rotation, patients in Group PMM walked with significantly larger tibial external rotation when compared with Group MMR by approximately 3.4° to 3.7° (loading response: P = .026, η2 = 0.090; midstance: P = .035, η2 = 0.093) and Group Intact ( P = .028; η2 = 0.095) in the early stance phase. In addition, there was significantly increased anterior tibial translation in Groups MMR and PMM compared with Group Intact. Conclusion: ACL reconstruction (via transtibial technique) with concurrent PMM demonstrated larger adduction and external tibial rotation at 24 months of follow-up during level walking. Clinical Relevance: Patients undergoing different medial meniscal treatment strategies in the presence of ACL reconstruction showed distinct knee kinematics. These results suggest that MMR is strongly recommended during ACL reconstructive surgery to reduce the abnormal kinematics close to that of the ACL-intact condition.

PARP-1 inhibition attenuates the inflammatory response in the cartilage of a rat model of osteoarthritis

Aims Poly (ADP-ribose) polymerase (PARP) inhibitor has been reported to attenuate inflammatory response in rat models of inflammation. This study was designed to investigate the effect of PARP signalling in osteoarthritis (OA) cartilage inflammatory response in an OA rat model. Methods The OA model was established by anterior cruciate ligament transection with medial meniscectomy in Wistar rats. The poly (ADP-ribose) polymerase 1 (PARP-1) shRNA (short hairpin (sh)-PARP-1) and negative control shRNA (sh-NC) were delivered using a lentiviral vector and were intra-articularly injected into rats after surgery. The weight-bearing distribution of the hind limbs and the knee joint width were measured every two weeks. The expression levels of PARP-1, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in cartilage were determined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. The serum concentrations of inflammatory cytokines were detected using enzyme-linked immunosorbent assay (ELISA). Results PARP-1 expression level significantly increased in the cartilage of the established OA rat model. sh-PARP-1 treatment suppressed PARP-1 levels, decreased the Δ Force (the difference between the weight on ipsilateral limb and contralateral limb) and the knee joint width, inhibited cartilage matrix catabolic enzymes, and ameliorated OA cartilage degradation and attenuated inflammatory response. Conclusion PARP-1 inhibition attenuates OA cartilage inflammatory response in the OA rat model. Cite this article: Bone Joint Res 2021;10(7):401–410.

Tibial tuberosity transposition advancement for treatment of concomitant cranial cruciate ligament rupture and medial patellar luxation in four feline stifles

Case series summary Three cats (four stifles) were diagnosed with varying grades of medial patellar luxation and stifle instability in cranial tibial thrust. Radiographs showed periarticular osteophytosis, intra-articular mineralization and opacification encroachment of the infrapatellar fat pad. Stifle exploration revealed either partial (n = 2) or complete (n = 2) cranial cruciate ligament tear and medial meniscal injury in all cases. Medial meniscectomy, partial parasagittal patellectomy, femoral trochleoplasty and tibial tuberosity transposition advancement using a 6 mm cage, two-fork plate and 4 mm spacer were performed in four stifles. Screws (2.0 mm) and washers were used in the cranial cage ears rather than conventional 2.4 mm screws. By the 2-week recheck, lameness was minimal and stifles were stable. Radiographic follow-up at 8 weeks showed appropriate progression of osseous union in all cases. One cat experienced a major complication, suffering tibial fracture following a lapse in exercise restriction, and revision surgery was performed successfully with subsequent osseus union of the osteotomy site. At the mid-term follow-up, all cats had a return to previous level of function, as assessed by both owner questionnaire and clinical evaluation. Relevance and novel information Tibial tuberosity transposition and advancement has been shown to be successful in dogs for the treatment of concomitant medial patellar luxation and cranial cruciate ligament rupture. To date, there have been no reports of tibial tuberosity transposition and advancement in cats. A benefit of this approach is concomitant alignment of the extensor mechanism and neutralization of the femorotibial shear force. Our case series describes successful use of tibial tuberosity transposition advancement in cats.

Aseptic Revision and Reoperation Risks After Meniscectomy at the Time of Anterior Cruciate Ligament Reconstruction

Background: An intact meniscus is considered a secondary stabilizer of the knee after anterior cruciate ligament reconstruction (ACLR). While loss of the meniscus can increase forces on the anterior cruciate ligament graft after reconstruction, it is unclear whether this increased loading affects the success of the graft after ACLR. Purpose: To identify the risk of subsequent knee surgery when meniscectomy, either partial or total, is performed at the time of index ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: We conducted a matched cohort study using data from the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry. Patients were identified who had a primary ACLR performed between January 1, 2005 and December 31, 2016, with up to 12 years of follow-up. The study sample comprised patients with ACLR who had a lateral meniscectomy (n = 2581), medial meniscectomy (n = 1802), or lateral and medial meniscectomies (n = 666). For each meniscectomy subgroup, patients with ACLR alone were matched to patients with a meniscectomy on a number of patient and procedure characteristics. After the application of matching, Cox proportional hazards regression was used to evaluate the risk of aseptic revision, while competing risks regression was used to evaluate the risk of cause-specific ipsilateral reoperation between meniscectomy and ACLR alone. Analysis was performed for each meniscectomy subgroup. Results: After the application of matching, we failed to observe a difference in aseptic revision risk for patients with ACLR and a meniscectomy—lateral (hazard ratio [HR], 0.80; 95% CI, 0.63-1.02), medial (HR, 0.95; 95% CI, 0.70-1.29), or both (HR, 1.25; 95% CI, 0.77-2.04)—as compared with ACLR alone. When compared with patients who had ACLR alone, patients with a lateral meniscectomy had a higher risk for subsequent lateral meniscectomy (HR, 1.89; 95% CI, 1.18-3.02; P = .008), and those with a medial meniscectomy had a lower risk for manipulation under anesthesia (HR, 0.13; 95% CI, 0.02-0.92; P = .041). Conclusion: No difference in aseptic revision risk was observed for patients undergoing primary ACLR between groups with and without meniscectomy at the time of index surgery. Partial lateral meniscectomy at the time of index ACLR did associate with a higher risk of subsequent lateral meniscectomy.

Evaluation of CCL21 role in post-knee injury inflammation and early cartilage degeneration

The expression of some chemokines and chemokine receptors is induced during the development of post-traumatic osteoarthritis (PTOA), but their involvement in the pathogenesis of the disease is unclear. The goal of this study was to test whether CCL21 and CXCL13 play a role in PTOA development. For this purpose, we evaluated the expression profiles of the chemokines Ccl21 and Cxcl13, matrix metalloproteinase enzymes Mmp3 and Mmp13, and inflammatory cell markers in response to partial medial meniscectomy and destabilization (MMD). We then assessed the effect of local administration of CCL21 neutralizing antibody on PTOA development and post-knee injury inflammation. The mRNA expression of both Ccl21 and Cxcl13 was induced early post-surgery, but only Ccl21 mRNA levels remained elevated 4 weeks post-surgery in rat MMD-operated knees compared to controls. This suggests that while both CXCL13 and CCL21 are involved in post-surgery inflammation, CCL21 is necessary for development of PTOA. A significant increase in the mRNA levels of Cd4, Cd8 and Cd20 was observed during the first 3 days post-surgery. Significantly, treatment with CCL21 antibody reduced post-surgical inflammation that was accompanied by a reduction in the expression of Mmp3 and Mmp13 and post-MMD cartilage degradation. Our findings are consistent with a role for CCL21 in mediating changes in early inflammation and subsequent cartilage degeneration in response to knee injury. Our results suggest that targeting CCL21 signaling pathways may yield new therapeutic approaches effective in delaying or preventing PTOA development following injury.