Clinical efficacy of arthroscopic high-intensity suture binding combined with button plate suspension fixation in the treatment of posterior cruciate ligament tibial avulsion fractures.

PURPOSE: To assess the clinical efficacy of arthroscopic treatment for posterior cruciate ligament (PCL) tibial avulsion fractures using high-intensity suture binding combined with button plate suspension fixation. METHODS: We retrospectively analyzed clinical data from 32 patients with PCL tibial avulsion fractures treated at our hospital from July 2020 to August 2023. We recorded operation time, intraoperative and postoperative complications, and used imaging to assess fracture reduction and healing. Pain and knee function were evaluated using the Visual Analogue Scale (VAS), range of knee motion, Lysholm score, and International Knee Documentation Committee (IKDC) score. STUDY DESIGN: Case series; Level of evidence, 4. RESULTS: All patients were followed for 6 to 18 months, averaging 13.6 months. All incisions healed successfully without postoperative complications. X-rays taken on the first postoperative day showed satisfactory fracture reduction. Three-month post-surgery imaging confirmed healed fractures and no internal fixation failures. At the final follow-up, knee function was well recovered, with only one patient exhibiting a positive posterior drawer test of degree I. Furthermore, the mean VAS score was 0. 5 (range 0.0 to 1.0), active knee extension was 2. 2° (range 0.0 to 5.0), and active knee flexion was 137.7° (range 130.0 to 145.0). The mean Lysholm score was 91.5(range 89.3 to 94.0), and the IKDC score averaged 83.8 ± 3.7, and these outcomes showed statistically significant improvement from preoperative levels (P < 0.001). CONCLUSIONS: Arthroscopic high-intensity suture binding combined with button plate suspension fixation for PCL tibial avulsion fractures offers several benefits: it is minimally invasive, results in less postoperative pain, enables earlier functional exercise, and provides satisfactory clinical outcomes with fewer complications.

[Prognostic evaluation of hip joint function following capsule repair based on a threedimensional finite element analysis model].

OBJECTIVE: To construct a three-dimensional (3D) finite element mechanical model of total hip arthroplasty for comparison of biomechanical differences of the hip joint following capsule repair and postoperative rehabilitation. METHODS: Six frozen specimens of hip joint posterior capsule ligament complex were collected in a bone-capsule-bone manner, and the load-strain curve and other mechanical properties of the specimens were tested using a universal material testing machine. Thin-section CT data of the pelvis and lower limbs obtained from a volunteer were imported into Mimics software to construct a 3D model of the hip joint. Digital models of the cup, femoral prosthesis and joint capsule were created in CATIA software and imported into Mimics to simulate total hip arthroplasty; the assembled data were imported into ABAQUS software. The properties of the capsule were set according to results of the mechanical test, anatomical studies, and constitutive equations, and the biomechanics of the anatomically repaired and conventionally repaired capsules were compared during hip flexion. RESULTS: The results of testing on the 6 capsule specimens showed a mean ultimate tensile strain of (39.21±5.23)% and a mean of ultimate tensile strength of 1.65±0.38 MPa. The stress-strain curve of the finite element model was consistent with the results of mechanical test on the specimens and the biochemical characteristics of the capsule. The stress was distributed evenly in the anatomically repaired capsule during hip flexion but not in the capsule repaired through the conventional approach; the tensile stress in the lower part of the conventionally repaired capsule reached the ultimate tensile stress measured on the capsule specimens at a 90° flexion. CONCLUSIONS: The finite element model allows dynamic, quantitative and visual assessment of stress distribution in the hip joint capsule, and compared with the conventional approach, anatomical repair can achieve better biomechanical properties of the capsule.

[Anatomical and tensile mechanical analysis of hip joint capsule repair in total hip replacement].

OBJECTIVE: To explore the tensile mechanics and anatomical characteristics of the posterior hip capsule, and provide biomechanical and anatomical evidence for capsule repair in total hip replacement. METHODS: Six bone-capsule-bone specimens were obtained from posterior hip joint of fresh frozen cadavers. The maximum strain, load, elastic modulus and load strain curves of the capsule ligament complex specimens were recorded by Instron Universal Material Testing Machine. Twelve cadaveric hip specimens were dissected to the capsule. The tensile strain of normal capsule and conventionally reconstructed capsule at 90 degrees of hip flexion were documented. The suture area of the posterior capsule was divided into nine sections, and the thicknessof different sections was measured and compared. Posterior capsule of the cadavers was repaired in conventionally way and anatomical way separately and simulated rehabilitation was conducted. The effect of rehabilitation on the repaired capsule was observed. RESULTS: The load-strain curve of capsule ligament complex conforms to rheological and viscoelastic characteristics. The maximum tensile strain of the complex was (39.21±5.23)%, the maximum load was (142.06± 34.15) N, the tensile strength was (1.65±0.38) MPa, and the elastic modulus is (14.23±5.62) MPa. At 90 ° hip flexion, the tensile strain of repaired capsule was higher than that of normal capsule, and the difference was statistically significant (P< 0.05). Tensile strain of conventionally reconstructed capsule is:upper part (37.0±4.9)%, middle part ( 53.3±1.1)%, lower part (68.3±6.2)%, tensile strain of normal capsule is:upper part (17.0±2.6)%, middle part (24.1±1.4)%, lower part (26.0± 4.3)% . The thickness of the posterior joint capsulein different sections is statistically significant (P<0.05), and capsule at 0.5cm proximal to the femoral insertion is suitable for suture. There the average thickness of capsule is:upper part (3.48 ± 0.11) mm, middle part (2.36 ± 0.09) mm, lower part (1. 59±0.24) mm. The posterior inferior joint capsule is thinnest at (1.42± 0.02) cm proximal to the femoral insertion, and sutures should be avoided here. After simulating rehabilitation, avulsion occurred in the lower part of the posterior capsule repaired conventionally (10/12), and the anatomically repaired capsule remained intact. CONCLUSION: The lower part of conventionally repaired capsule is overstretched and tends to fail. Anatomically repaired capsule conforms to tensile mechanics and is helpful to reduce the failure rate of repair.

Development of a centrally vascularized tissue engineering bone graft with the unique core-shell composite structure for large femoral bone defect treatment.

Great effort has been spent to promote the vascularization of tissue engineering bone grafts (TEBG) for improved therapeutic outcome. However, the thorough vascularization especially in the central region still remained as a major challenge for the clinical translation of TEBG. Here, we developed a new strategy to construct a centrally vascularized TEBG (CV-TEBG) with unique core-shell composite structure, which is consisted of an angiogenic core and an osteogenic shell. The in vivo evaluation in rabbit critical sized femoral defect was conducted to meticulously compare CV-TEBG to other TEBG designs (TEBG with osteogenic shell alone, or angiogenic core alone or angiogenic core+shell). Microfil-enhanced micro-CT analysis has been shown that CV-TEBG could outperform TEBG with pure osteogenic or angiogenic component for neo-vascularization. CV-TEBG achieved a much higher and more homogenous vascularization throughout the whole scaffold (1.52-38.91 folds, p < 0.01), and generated a unique burrito-like vascular network structure to perfuse both the central and peripheral regions of TEBG, indicating a potential synergistic effect between the osteogenic shell and angiogenic core in CV-TEBG to enhance neo-vascularization. Moreover, CV-TEBG has generated more new bone tissue than other groups (1.99-83.50 folds, p < 0.01), achieved successful bridging defect with the formation of both cortical bone like tissue externally and cancellous bone like tissue internally, and restored approximately 80% of the stiffness of the defected femur (benchmarked to the intact femur). It has been further observed that different bone regeneration patterns occurred in different TEBG implants and closely related to their vascularization patterns, revealing the potential profound influence of vascularization patterns on the osteogenesis pattern during defect healing.

Anatomical principles for minimally invasive reconstruction of the acromioclavicular joint with anchors.

PURPOSE: The aim of this study was to evaluate the outcome of a minimally invasive surgical technique for the treatment of patients with acromioclavicular joint dislocation. METHODS: Sixteen patients with complete acromioclavicular joint dislocation were enrolled in this study. All patients were asked to follow the less active rehabilitation protocol post-operatively. Computed tomography with 3-D reconstruction of the injured shoulder was performed on each patient post operatively for the assessment of the accuracy of the suture anchor placement in the coracoid process and the reduction of the acromioclavicular joint. Radiographs of Zanca view and axillary view of both shoulders were taken for evaluating the maintenance of the acromioclavicular joint reduction at each follow-up visit. The Constant shoulder score was used for function assessment at the final follow-up. RESULTS: Twenty seven of the 32 anchors implanted in the coracoid process met the criteria of good position. One patient developed complete loss of reduction and another had partial loss of reduction in the anteroposterior plane. For the other 14 patients, the mean Constant score was 90 (range, 82-95). For the patients with partial and complete loss of reduction, the Constant score were 92 and 76 respectively. All of them got nearly normal range of motion of the shoulders and restored to pre-operative life and works. CONCLUSION: With this minimally invasive approach and limited exposure of the coracoid, a surgeon can place the suture anchors at the anatomical insertions of the coracoclavicular ligament and allow the dislocated joint reduced and maintained well. LEVEL OF EVIDENCE: Level IV, Case series; therapeutic study.

Effects of mesenchymal stem cells on interleukin-1ß-treated chondrocytes and cartilage in a rat osteoarthritic model.

In the present study, the effects and mechanisms of mesenchymal stem cells (MSCs) on interleukin (IL)-1ß-stimulated rat chondrocytes, as well as cartilage from a rat model of osteoarthritis (OA) induced by anterior cruciate ligament transection and medial meniscectomy were investigated. Confluent rat chondrocytes were treated with IL-1ß (10 ng/ml), then cultured indirectly with or without MSCs at a ratio of 2:1. Total RNA and protein were collected at various time-points, and western blot and reverse transcription-quantitative polymerase chain reaction analyses were used to investigate the expression of type II collagen (Col2), aggrecan, matrix metalloproteinase-13 (MMP-13) and cyclooxygenase-2 (COX-2). The activation of extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB) p65 and inhibitory-κ-B-α (IκBα) were also assessed by western blotting. In addition, the in vivo effects of MSCs in a rat OA model were assessed by histology and western blot analysis. The results indicated that in vitro, IL-1ß markedly upregulated the expression of MMP-13, COX-2, phosphorylated ERK1/2, JNK, p38 MAPK and NF-κB p65, and inhibited the expression of Col2, aggrecan and IκBα. Conversely, MSCs enhanced the expression of Col2, aggrecan and IκBα, and inhibited the expression of MMP-13 and NF-κB p65 in IL-1ß-stimulated rat chondrocytes. In vivo histological and western blot analyses revealed analogous results to the in vitro findings. The results of the present study demonstrated that MSCs suppressed the inflammatory response and extracellular matrix degradation in IL-1ß­induced rat chondrocytes, as well as cartilage in a osteoarthritic rat model, in part via the NF-κB signaling pathway.

Comparison of the efficacy of bone marrow mononuclear cells and bone mesenchymal stem cells in the treatment of osteoarthritis in a sheep model.

OBJECTIVE: To evaluate the therapeutic efficacy of uncultured bone marrow mononuclear cells (BMMCs) and bone mesenchymal stem cells in an osteoarthritis (OA) model of sheep. METHODS: Induction of sheep OA was performed surgically through anterior cruciate ligament transection and medial meniscectomy. After 12 weeks, concentrated BMMCs obtained from autologous bone marrow harvested from anterior iliac crest or a single dose of 10 million autologous bone mesenchymal stem cells (BMSCs) suspended in phosphate-buffered saline (PBS) was delivered to the injured knee via direct intra-articular injection. Animals of the PBS group received vehicle alone. The contra-lateral joints were selected randomly as the control group. Knees of the four groups were compared macroscopically and histologically, and glycosaminoglycan (GAG) contents normalized to cartilage wet weight were measured at lesions of cartilage from medial condyle of the femur head. Gene expression levels of type II collagen (Col2A1), Aggrecan and matrix metalloproteinase-13 (MMP-13) in cartilage were measured based on RT-PCR and prostaglandin E2 (PGE2), Tumor Necrosis Factor-α (TNF-α) and Transforming Growth Factor beta (TGF-ß) concentrations in synovial fluid were determined with ELISA assays at 8 weeks after injection. RESULTS: At 8 weeks post cell transplantation, partial cartilage repair was observed in the cell therapy, but not the PBS group (P<0.05). The BMSCs group showed higher regeneration of cartilage and lower proteoglycan loss than the BMMCs group (P<0.05). Concentrated BMMCs injection led to a weaker treatment effect, but also inhibited PGE2, TNF-α and TGF-ß levels in synovial fluid and promoted higher levels of Aggrecan and Col2A1 and downregulation of MMP-13 in sheep chondrocytes in a similar manner to BMSCs, compared with the PBS group. CONCLUSIONS: Bone marrow cells showed therapeutic efficacy in a sheep model of OA. Despite similar therapeutic potential, the easier and faster process of collection and isolation of BMMCs supports their utility as an effective alternative for OA treatment in the clinic.

Immunomodulatory effectiveness of tacrolimus in preventing epidural scar adhesion after laminectomy in rat model.

There was no previous study about topical application of tacrolimus (FK506) could inhibit fibroblast proliferation and prevent epidural scar adhesion after laminectomy. We intended to illustrate the effect of FK506 on inhibiting fibroblast proliferation and preventing epidural scar adhesion after laminectomy in rat model. In our study, seventy-two rats were randomly divided into four groups (0.1mg/ml group, 0.05 mg/ml group, 0.01 mg/ml group and control group). Laminectomy was performed at Lumbar-1 level, and then different concentrations of FK506 and saline were applied to the laminectomy sites. Four weeks later the rats were killed and the epidural adhesion was evaluated. Macroscopic assessment, hydroxyproline content analysis, histological analysis and mRNA measurements were used to evaluate the effect of FK506 on reducing epidural scar adhesion. The results showed that FK506 could prevent epidural scar adhesion in a dose-dependent manner. Little epidural adhesions were seen in the laminectomy sites treated with 0.1mg/ml FK506. The hydroxyproline content, the number of fibroblasts, the mRNA expression level of IL-2 and TGF-ß1 in 0.1mg/ml FK506 group were significantly less than those of 0.05 mg/ml FK506 group, 0.01 mg/ml FK506 group and control group. However, dense epidural adhesions were found in 0.01 mg/ml FK506 group and control group. The hydroxyproline content and the number of fibroblasts in 0.01 mg/ml group showed no significant difference compared with those of control group. In conclusion, topical application of 0.1mg/ml FK506 could inhibit fibroblast proliferation and prevent epidural scar adhesion after laminectomy in rat model.

A comparative study of the preventive effects of mitomycin C and chitosan on intraarticular adhesion after knee surgery in rabbits.

We sought to compare the preventive effects of mitomycin-C(MMC) and chitosan on intraarticular adhesion after knee surgery in rabbits. For this purpose, 48 New-Zealand rabbits were randomly and equally divided into MMC, chitosan, and control groups. Approximately 10 × 10 mm(2) of the cortical bone was removed from both sides of left femoral condyle and the cancellous bone underneath was exposed. The decorticated areas were topically treated with MMC and chitosan while control group was treated with physiological saline. The lower left limb was fixed in flexed position with Kirschner-wire for 4 weeks postoperatively. After 4 weeks, gross and histopathological examination, biochemical analysis, and fibroblast counts were performed on knee intraarticular adhesion in each group. The data show mild membrane-like fibrous intraarticular adhesion, presented in loose, in MMC group. There was moderate intraarticular adhesion in chitosan group while in controls; there was large-size compact fibrous tissue adhesion. Hydroxyproline contents and fibroblast quantity of MMC and chitosan groups were lower (P < 0.05) than that of control group. We, therefore, concluded that MMC and chitosan could prevent intraarticular adhesion of the knee in rabbits by inhibiting fibroblast proliferation and reducing collagenous fiber formation while MMC had a better preventive effect than that of chitosan.