Intra-Articular Injection of Interleukin-8 Neutralizing Monoclonal Antibody Effectively Attenuates Osteoarthritis Progression in Rabbits.

OBJECTIVE: Cytokines are implicated in the pathogenesis of osteoarthritis (OA), and this study aims to assess the therapeutic potential of an IL-8 neutralizing monoclonal antibody (mAb) for OA intervention. DESIGN: The study employed a rabbit model of OA induced by anterior cruciate ligament transection (ACLT) surgery to investigate the effects of an interleukin (IL)-8 neutralizing mAb, with hyaluronic acid (HA) used as a positive control. Primary outcomes assessed in the rabbits included cartilage repair, synovitis, joint effusion, changes in footprints, and lower limb loading conditions. RESULTS: Compared to HA, intra-articular injection of the IL-8 neutralizing mAb demonstrated a more pronounced attenuation of OA progression and enhancement of cartilage repair. We observed a reduction in synovitis and joint effusion, indications of bone marrow edema, as well as improvements in lower limb function. In knees treated with the neutralizing IL-8 mAb, there was a significant decrease in IL-8 levels within the synovial tissues. CONCLUSIONS: The IL-8 neutralizing mAb exhibits promising therapeutic potential in the management of OA by attenuating inflammation and facilitating cartilage repair. However, further investigations are warranted to comprehensively elucidate the underlying mechanisms, optimize treatment protocols, and ensure the long-term safety and efficacy of this innovative therapeutic approach.

A Torn Discoid Lateral Meniscus Impacts Lower-Limb Alignment Regardless of Age: Surgical Treatment May Not Be Appropriate for an Asymptomatic Discoid Lateral Meniscus.

BACKGROUND: A discoid lateral meniscus (DLM) is more prone to tear, and treatment of this condition is challenging. The purpose of the present study was to investigate (1) whether a torn DLM is associated with more varus alignment than a torn semilunar lateral meniscus (SLM) and (2) whether the lower-limb alignment associated with a torn DLM changes with age. METHODS: Consecutive patients who underwent arthroscopic knee surgery for a torn lateral meniscus were included. Patients with a torn DLM (confirmed on arthroscopy) were allocated to the DLM group; those with a torn SLM were allocated to the SLM group. After strict screening according to the inclusion and exclusion criteria, 436 and 423 patients were included in the DLM and SLM groups, respectively. The mechanical axis deviation (MAD), hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle, and medial proximal tibial angle were compared between the 2 groups after propensity score matching. Additionally, the correlation of the HKA and MAD with age was evaluated within the DLM group. RESULTS: After propensity score matching, all baseline characteristics were well balanced between the 2 groups. The DLM group had significantly more varus alignment than the SLM group (MAD: 3.6 mm ± 9.6 mm versus 1.1 mm ± 10.3 mm, respectively, p = 0.001; HKA: 179.1° ± 2.9° versus 179.9° ± 3.0°, respectively, p = 0.001). Within the DLM group, the MAD (R = 0.10, p = 0.032) and HKA (R = -0.13, p = 0.007) had a weak correlation with age. CONCLUSIONS: Patients with a torn DLM had more varus knee alignment than those with a torn SLM, and this trend did not increase with age after minimizing the effects of osteoarthritis. Therefore, surgical treatment may not be appropriate for asymptomatic DLM. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Hip Pain after Distal Femoral Derotational Osteotomy for a Patient with Patellar Instability: A Case Report.

BACKGROUND: Increased torsional deformity of femur is one of the most important factors in recurrent patellofemoral instability. And distal femoral derotational osteotomy is an effective treatment option in patients with increased femoral torsional deformity. However, groin pain is a rare complication after femoral derotational osteotomy. CASE PRESENTATION: The patient was a 23-year-old female suffering from anterior knee pain and patellar instability in her left leg. Continuous CT scans of the hip, knee, and ankle were performed and the femoral anteversion was 44.99°. Considering the significant enlargement of the femoral internal torsion which may contribute most for dislocation of patella, we did a derotational osteotomy of distal femur. The anterior knee pain and patellar instability were resolved after surgery. The femoral internal torsion angle was corrected to 21.47°. But she developed left hip pain in the groin area which she had never encountered before 1 year after the surgery. We believed that the hip pain was closely related to the surgery. And the imaging and follow-up partly confirmed this. CONCLUSIONS: The situation of the hip joint should be carefully evaluated before doing derotational osteotomy in recurrent patellofemoral instability and patient should be informed that derotational osteotomy may cause hip pain. Clinical studies are needed to further clarify the impact of derotational osteotomy on the hip.

Proximal external femoral torsion increases lateral femoral shaft bowing: a study based on 3D CT reconstruction models.

PURPOSE: Femoral bowing influences the genesis and management of knee osteoarthritis (OA). The aim of this study was to investigate the relationship between the femoral torsion angle (FTA) and femoral bowing angle (FBA) in a southern Chinese population. It was hypothesized that a greater FTA would lead to a greater lateral FBA. METHODS: A total of 381 lower extremities from 381 osteoarthritic patients (298 women, 83 men; 201 left, 180 right; mean age 66.5 ± 8.9 years) were retrospectively reviewed. Age, sex, body mass index (BMI), side, height, femoral length (FL), hip-knee-ankle angle (HKA) and FTA were set as FBA-related factors. The three-dimensional (3D) FBA, the angle between the anatomical axis of the proximal femur and the anatomical axis of the distal femur in the plane they form, and its projection on the coronal (lateral FBA) and sagittal (anterior FBA) planes were measured on 3D computed tomography (CT) models. The correlation of the 3D, lateral and anterior FBAs with each of the FBA-related factors was explored using multiple linear regression analysis. The correlation between the FBA and FTA was explored and verified after using propensity score matching to control for the other FBA-related factors. RESULTS: The mean lateral and anterior FBAs were 5.5°, with 53.5% greater than 5°, and 12.7°, with 70.3% greater than 11°, respectively. 3D FBA was positively correlated with age (Std.Co = 0.113, P < 0.05) and HKA (Std.Co = 0.129, P < 0.05). Lateral FBA was positively correlated with age (Std.Co = 0.118, P < 0.05), female sex (Std.Co = 0.206, P < 0.05), HKA (Std.Co = 0.184, P < 0.05) and FL (Std.Co = 0.220, P < 0.05). Anterior FBA was positively correlated with age (Std.Co = 0.108, P < 0.05) and male sex (Std.Co = 0.108, P < 0.05). When the related factors were balanced between the two groups (NS), FTA did not significantly affect 3D FBA or anterior FBA (NS), while FTA was positively correlated with lateral FBA (Std.Co = 0.165, P < 0.05). CONCLUSION: External torsion of the proximal femur increases the lateral FBA by twisting a partial anterior FBA into a lateral FBA, especially in the female population. If a patient is found to have a large lateral FBA preoperatively, one should be alert to the possibility of a concomitant large FTA, as there are implications for femoral orthopedics, TKA and patellofemoral pressure distribution. LEVEL OF EVIDENCE: III.

Surgical Transepicondylar Axis Is Not a Reliable Reference when there Was Lateral Femoral Bowing.

OBJECTIVE: The surgical transepicondylar axis (sTEA) is believed to be a consistent reference for femoral rotation axis, and the reliability of its orientation seriously affects the accuracy and outcome of total knee arthroplasty (TKA). This study was designed to investigate the relationship between the orientation of sTEA and femoral bowing angle (FBA) and posterior condylar line (PCL) using three-dimensional (3D) computed tomography (CT) reconstruction models to verify its reliability. METHODS: This study retrospectively collected lower extremity images of 443 southern Chinese osteoarthritic patients (347 women, 96 men; 234 left, 209 right; mean age 66.5 ± 9.3 years) from August 2016 to June 2018. The hip-knee-ankle angle (HKA) was measured on anteroposterior weight-bearing full lower extremity standing radiographs. Measurements on 3D CT models of the femurs included lateral angle between the femoral mechanical axis and sTEA coronal angle, angle between sTEA and distal joint line (distal condylar axis angle, DCA); angle between sTEA and PCL (sTEA axial angle); angle between anatomical axis of proximal femur and anatomical axis of distal femur in the plane they form (actual FBA) and its projection on the coronal (lateral FBA) and sagittal (anterior FBA) planes. The correlations between sTEA coronal angle, sTEA axial angle and actual FBA, lateral FBA, anterior FBA, HKA, DCA were explored using the Spearman correlation test. RESULTS: The mean value of actual FBA is (14.4 ± 3.6)°, of lateral FBA is (6.0 ± 4.0)°, and of anterior FBA is (12.7 ± 3.0)°. The mean value of sTEA coronal angle is (88.7 ± 3.6)°, of sTEA axial angle is (2.1 ± 2.8)°. The sTEA coronal angle was positively correlated with actual FBA (r = 0.320, P < 0.01), lateral FBA (r = 0.448, P < 0.01), anterior FBA (r = 0.113, P < 0.05), HKA (r = 0.482, P < 0.01) and DCA (r = 0.486, P < 0.01). The sTEA axial angle was positively correlated with DCA (r = 0.168, P < 0.01), but not significantly correlated with all FBAs and HKA (NS). CONCLUSION: The sTEA cannot be used as a stable reference when there was an obvious femoral bowing deformity. As the lateral femoral bowing increases, the orientation of sTEA becomes more varus, no matter the knee is varus or valgus.

A case report: anatomical translocation in tibial insertion of semitendinosus tendon after tibial lengthening.

BACKGROUND: There is the most common method for arthroscopic anterior cruciate ligament (ACL) reconstruction by using the semitendinosus and gracilis tendons and single-tunnel technique. However, anatomic translocation of hamstring tendon attachment is very rare. CASE PRESENTATION: A 45-year-old male who need to receive right knee ACL reconstruction due to sprain injury while playing table tennis was found to have a translocation at tibial attachment of semitendinosus tendon. The tibial insertion of left semitendinosus was then explored by ultrasound and found to be identical to the contralateral limb. The patient has a history of bilateral tibial lengthening. CONCLUSIONS: This is the first case as far as we know that reported anatomic translocation of the tibial attachment of the hamstring tendon after tibial lengthening. Surgeons should be aware of this specific situation when hamstring tendon need to be harvested to avoid unnecessary complications.

Application of three-dimensional-printed porous tantalum cones in total knee arthroplasty revision to reconstruct bone defects.

Purpose: Three-dimensional (3D) printing technology has emerged as a new treatment method due to its precision and personalization. This study aims to explore the application of a 3D-printed personalized porous tantalum cone for reconstructing the bone defect in total knee arthroplasty (TKA) revision. Methods: Between November 2017 and October 2020, six patients underwent bone reconstruction using 3D-printed porous tantalum cones in TKA revision. The knee function was assessed using the Hospital for Special Surgery (HSS) score pre- and postoperatively. The pain was measured by the visual analog scale (VAS) pre- and postoperatively. The quality of life was measured using the 36-Item Short Form Health Survey (SF-36) to pre- and postoperatively evaluate the relief of pain. Operation time, intraoperative blood loss, postoperative drainage volume, and complications were also recorded. At the last follow-up, all patients received X-ray and computed tomography (CT) to confirm the effect of bone reconstruction. Results: After an average follow-up duration of 26.3 months, no patients developed any operation-related complications. The average intraoperative blood loss and postoperative drainage volumes were 250.1 ± 76.4 ml and 506.7 ± 300.8 ml, respectively. At the last follow-up, the HSS score was significantly higher than that before operation, indicating that the knee function was significantly improved (p < 0.001). During the follow-up, the mean VAS score decreased and the mean SF-36 score increased, both of which were significantly improved compared with preoperative conditions (p < 0.001). Radiological examination at the final follow-up showed that cones implanted into the joint were stable and bone defects were effectively reconstructed. Conclusion: This study demonstrated that 3D-printed porous tantalum cones could effectively reconstruct bone defects and offer anatomical support in TKA revision. Further studies are still needed to confirm the long-term effect of 3D-printed tantalum cones for reconstructing bone defects.

Slight femoral under-correction versus neutral alignment in total knee arthroplasty with preoperative varus knees: a comparative study.

BACKGROUND: This study aimed to compare the short-term clinical results of slight femoral under-correction with neutral alignment in patients with preoperative varus knees who underwent total knee arthroplasty. METHODS: The medical records and imaging data were retrospectively collected from patients who had undergone total knee arthroplasty in our hospital from January 2016 to June 2019. All patients had varus knees preoperatively. Upon 1:1 propensity score matching, 256 patients (256 knees) were chosen and divided into a neutral alignment group (n=128) and an under-correction group (n=128). The patients in the neutral group were treated with the neutral alignment. In the under-correction group, the femoral mechanical axis had a 2° under-correction. The operative time, tourniquet time and the length of hospital stay in the two groups were recorded. The postoperative hip-knee-ankle angle, frontal femoral component angle and frontal tibial component angle were measured. Patient-reported outcome measures were also compared. RESULTS: The operative time, tourniquet time and the length of hospital stay in the under-correction group were significantly shorter than the neutral alignment group (P<0.05). At the 2-year follow-up, the under-correction group had a larger varus alignment (P<0.05) and a larger frontal femoral component angle (P<0.05), and the frontal tibial component angles of the two groups were comparable. Compared with the neutral alignment group, the slight femoral under-correction group had significantly better patient-reported outcome measures scores (P<0.05). CONCLUSION: For varus knees treated with total knee arthroplasty, alignment with a slight femoral under-correction has advantages over the neutral alignment in terms of the shorter operative time and better short-term clinical results. LEVEL OF EVIDENCE: III.

Methacrylated pullulan/polyethylene (glycol) diacrylate composite hydrogel for cartilage tissue engineering.

Pullulan hydrogels are widely used in tissue engineering and drug delivery. However, these hydrogels do not meet the requirements of articular cartilage repair because of their fast degradation rate and poor mechanical strength. Herein, we fabricated a hybrid hydrogel system by combining pullulan with synthetic polymers polyethylene (glycol) diacrylate (PEGDA). In this study, pullulan was modified with methacrylic anhydride (MA) to obtain photo-crosslinkable methacrylated pullulan (PulMA). Moreover, the lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (LAP) was used as a water-soluble UV photoinitiator to form the PulMA/PEGDA hydrogel by photopolymerization strategy. Compared with the pure PulMA hydrogel, the increase of PEGDA concentration led to a slower degradation rate and an increase of residual mass from 63.9% to 86.8%. There was about 8-fold increase in storage modulus (G') (reach to 16.0 × 103 Pa) and 13-fold increase in compressive modulus (reach to 1.17 ± 0.17 MPa) with increasing the concentration of PEGDA to 15% (w/v) in the hydrogel. In cell culture in vitro, the rabbit's mesenchymal stem cells (MSCs) encapsulated in the PulMA/PEGDA hydrogel could adhere and proliferate, indicating that the PulMA/PEGDA hydrogel had a good biocompatibility. Furthermore, the hydrogels supported glycosaminoglycan (GAG) synthesis, and chondrogenic phenotype of MSCs with TGF-ß3-containing chondrogenic medium. This study demonstrated that the photo-crosslinking PulMA/PEGDA hydrogels, with good mechanical properties and slow degradation rate are promising scaffolds for cartilage repair and regeneration.

Gait Analysis after Total Knee Arthroplasty Assisted by 3D-Printed Personalized Guide.

BACKGROUND: With the development of three-dimensional printing (3DP) technology, the patient-specific instrumentation (PSI) has been widely applied in total knee arthroplasty (TKA). The purpose of this study was to compare the gait parameters of patients with 3DP personalized guide-assisted and standard TKA. METHODS: Retrospective analysis of the advanced knee OA cases in our hospital between June 2017 and June 2018 was conducted. 30 cases received 3DP personalized guide-assisted TKA (group A), and 60 patients who underwent standard TKA during the same period were in group B and group C according to the computed tomography (CT) measurement results, each with 30 cases. Hip-knee-ankle angle (HKA), patella transverse axis-femoral transepicondylar axis angle (PFA), and gait parameters were statistically analyzed. The function was assessed by Hospital for Specific Surgery (HSS) and Knee Society Score (KSS). RESULTS: The mean follow-up period was 12.3 months in the three groups. The knee max flexion angle at the swing phase of group A was larger than group B and group C (P < 0.05), there was no statistically significant difference in other gait parameters. The mean PFA of group A was smaller than that of group B and group C (P < 0.05). While, the HKA, HSS, and KSS scores of three groups showed no significant difference. CONCLUSION: 3DP personalized guide technology could improve the gait parameters after surgery, specifically reflected in the knee max flexion angle at the swing phase. It could also assist in the reconstruction of more accurate patellar tracking and rotational alignment in TKA, avoiding the occurrence of insufficient or excessive extorsion.

Asiatic acid attenuates hypertrophic and fibrotic differentiation of articular chondrocytes via AMPK/PI3K/AKT signaling pathway.

BACKGROUND: Osteoarthritis (OA), the most common joint disorder, is characterized by a progressive degradation of articular cartilage. Increasing evidence suggests that OA is closely associated with cartilage pathologies including chondrocyte hypertrophy and fibrosis. METHODS: In this study, we showed that asiatic acid (AA) treatment reduced chondrocyte hypertrophy and fibrosis. First, the cytotoxicity of AA (0, 5, 10, and 20 µM) to chondrocytes was evaluated, and 5 µM was selected for subsequent experiments. Then, we detected the gene and protein level of chondrocyte hypertrophic markers including type X collagen (COL-X), matrix metalloproteinase-13 (MMP-13), alkaline phosphatase (ALP), and runt-related transcription factor 2 (Runx2); chondrocyte fibrosis markers including type I collagen (COL-Ι) and alpha-smooth muscle actin (α-SMA); and chondrogenic markers including SRY-related HMG box 9 (SOX9), type II collagen (COL-II), and aggrecan (ACAN). Further, we tested the mechanism of AA on inhibiting chondrocyte hypertrophy and fibrosis. Finally, we verified the results in an anterior cruciate ligament transection (ACLT) rat OA model. RESULTS: We found that AA treatment inhibited the hypertrophic and fibrotic phenotype of chondrocytes, without affecting the chondrogenic phenotype. Moreover, we found that AA treatment activated AMP-activated protein kinase (AMPK) and inhibited phosphoinositide-3 kinase/protein kinase B (PI3K/AKT) signaling pathway in vitro. The results in an ACLT rat OA model also indicated that AA significantly attenuated chondrocyte hypertrophy and fibrosis. CONCLUSION: AA treatment could reduce hypertrophic and fibrotic differentiation and maintain the chondrogenic phenotype of articular chondrocytes by targeting the AMPK/PI3K/AKT signaling pathway. Our study suggested that AA might be a prospective drug component that targets hypertrophic and fibrotic chondrocytes for OA treatment.

Accuracy of a Novel 3D-Printed Patient-Specific Intramedullary Guide to Control Femoral Component Rotation in Total Knee Arthroplasty.

OBJECTIVE: Total knee arthroplasty (TKA) is one of the most universal and effective means for treating terminal stage osteoarthritis (OA) of knee. Accurate intramedullary guide of femur is the basis for the distal femoral cuts. Determining the surgical transepicondylar axis (sTEA) is the key to reconstruction of the femoral rotational alignment, because the correct rotational alignment can place the femoral component in the right position, balance the flexion gap so that the inner and outer tension is equal, get stability during the flexion process of the knee, and enhance the quality of life of patients. With the development of three-dimensional printing (3DP) technology in the medical domain, the application of patient-specific instrumentation (PSI) in arthroplasty has become more common. The aim of this study was to evaluate the accuracy of a novel 3D-printed patient-specific intramedullary guide to control femoral component rotation in TKA. METHODS: Eighty patients (65 females and 15 males) with knee OA were included in this prospective randomized study. The patients were divided into two groups by random number table method, 40 in each group. TKA assisted by PSI (PSI group) and conventional TKA (conventional group) was performed respectively. Clinical outcomes [operation time, postoperative drainage volume, duration of drainage, Hospital for Special Surgery knee score (HSS), American Knee Society knee score (AKS)] and radiological outcomes [hip-knee-ankle angle (HKA), posterior condylar angle (PCA), patella transverse axis-femoral transepicondylar axis angle (PFA), depth of intramedullary guide] were compared between and within the two groups. RESULTS: PSI group had less postoperative drainage volume but longer operation time than the conventional group (P < 0.05). The AKS and HSS scores after surgery were improved compared with those before surgery in each group (P < 0.05). However, there was no significant difference in the duration of drainage and range of motion (ROM) after surgery between the two groups. For the radiological results, the HKA and PFA were improved after surgery in both groups (P < 0.05).The postoperative PFA and PCA of the PSI group were closer to 0°, which was better than that of the conventional group (P < 0.05). The depth of intramedullary guide in the PSI group was less than the conventional group (P < 0.05). But there was no significant difference in HKA before and after surgery between the two groups as well as the preoperative PFA. CONCLUSION: The short-term clinical efficacy of TKA assisted by PSI was similar to the conventional TKA. Although TKA assisted by PSI spent more time during operation, it could assist in intramedullary guide and align femoral rotation more accurately.

An Arthroscopic Second-Look Study on the Effect of Remnant Preservation on Synovialization of Bone-Patellar Tendon-Bone Allograft in Anterior Cruciate Ligament Reconstruction.

PURPOSE: To assess the effects of preserved more anterior cruciate ligament (ACL) remnant on synovial coverage, knee stability, and function after bone patellar-tendon-bone (BPTB) allograft reconstruction through second-look arthroscopy and follow-up study. METHODS: From June 2007 to February 2009, 51 patients received single bundle BPTB allograft ACL reconstruction and second arthroscopic examination. The patients were divided into 4 types according to the types of ACL remnant: type 1, 18 had bridging between the posterior cruciate ligament and the tibia; type 2, 21 had bridging between the intercondylar notch roof and the tibia; type 3, 4 had bridging between the lateral condyle and the tibia; and type 4, 8 subjects had no ACL remnants. Clinical results were evaluated with the KT-1000 maximum displacement test and Lysholm scale at mean 12.3- and 53.5-month follow-up. Second-look synovium coverage was recorded as follows: covering 25% or less, 25% to 50%, 50% to 75%, and more than 75%. RESULTS: Mean percentage of synovium coverage, Lysholm scale, and KT-1000 side-to-side difference were poorer in types 3 and 4 than the other 2 types at mean 12.3-month follow-up without statistical differences. The result of the final follow-up was comparable with the first one. Four patients had ruptured grafts and accepted revision surgery. Three of them belonged to types 3 and 4, and 1 patient with sport trauma belonged to type 2. There were other 11 patients with different types of impingement and partial absorption of grafts. CONCLUSIONS: Although lack of statistical power, follow-up study and second-look arthroscopy showed that preserved type 3 and 4 ACL remnant caused poorer synovium coverage and might lead to earlier failure when using BPTB allograft. Early minor laxity at 12.3-month follow-up seemed to be not progressive at the final follow-up. LEVEL OF EVIDENCE: Level III, case-control study.

Discoid lateral meniscus tears and concomitant articular cartilage lesions in the knee.

PURPOSE: The purpose of this study was to investigate the relation between isolated discoid lateral meniscus (DLM) tears and the presence of articular cartilage lesions. METHODS: From January 2010 to January 2012, 252 consecutive patients diagnosed with an isolated DLM tear during an arthroscopic procedure were included in this study. Demographic variables, including gender, age, body mass index (BMI), traumatic history, time course, and date of the DLM tear, were recorded. The relation between DLM tears and the presence of articular cartilage lesions was analyzed by the χ(2) test. Logistic regression analysis was used to analyze the relation between these variables and articular cartilage lesions. RESULTS: Of the patients with DLM tears, 67 (26.6%) also had articular cartilage lesions. The most common type of DLM tear was the complex tear (46.8%). The most common location of articular cartilage lesions was the lateral tibial plateau (11.6%). Lesions on the opposing articular surfaces of the lateral compartment and patellofemoral joint of the knee were found in 12 patients (4.8%) and 11 patients (4.4%), respectively. There were no significant differences in the incidences of articular cartilage lesions in patients with different types of DLM tears (P > .05). Gender (odds ratio [OR], 2.289; P = .012), BMI (OR, 1.991; P = .023), and time course (OR, 2.050; P = .034) were significantly associated with articular cartilage lesions. CONCLUSIONS: DLM tears were more common in the context of degenerative tears. There was no significant difference in the incidence of articular cartilage lesions among patients with different types of DLM tears. Female patients, patients with a BMI greater than 23.0 kg/m(2), or patients with a time course of greater than 6 months were more frequently observed to also have articular cartilage lesions. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Use of intravenous tranexamic acid in total knee arthroplasty: a meta-analysis of randomized controlled trials.

OBJECTIVE: The effect of tranexamic acid (TA) on patients receiving total knee arthroplasty (TKA) has been reported in many small clinical trials. But single trials are not sufficient enough to clarify the effectiveness and safety of TA. So, we carried out a meta-analysis of randomized controlled trials to investigate the efficacy and safety of the intravenous use of TA in TKA. METHODS: Literatures were retrieved in Cochrane Library, OVID, PubMed, EMBASE, CNKI and Wanfang Data. All the related literatures were checked by two independent investigators and only the high quality randomized controlled trials were enrolled. Relevant data were analyzed using RevMan 5.1 to compare the difference of blood loss, transfusion and complications between TA group and control group. RESULTS: There were 353 related literatures and only 22 randomized controlled trials met the inclusion criteria. The use of TA in TKA significantly reduced total blood loss by a mean of 435.41 ml (95% CI 300.62-570.21, P less than 0.01), post-operative blood loss by a mean of 406.69 ml (95% CI 333.16-480.22, P less than 0.01). TA also significantly lowered the transfusion rate (risk difference 0.30, 95% CI 0.21-0.39, P less than 0.01) and transfusion volume (mean difference 0.95 unit, 95% CI 0.53-1.37, P less than 0.01). The risks between TA group and control group in developing deep vein thrombosis and pulmonary embolism were not statistically significant. CONCLUSION: TA is beneficial for patients undergoing TKA, which can significantly reduce total blood loss, postoperative blood loss, transfusion rate, and transfusion volume. Meanwhile TA is recommended to reduce deep vein thrombosis and pulmonary embolism following TKA.