Tendon-bone Healing Research Articles

Stem cell therapies in tendon-bone healing.

Tendon-bone insertion injuries such as rotator cuff and anterior cruciate ligament injuries are currently highly common and severe. The key method of treating this kind of injury is the reconstruction operation. The success of this reconstructive process depends on the ability of the graft to incorporate into the bone. Recently, there has been substantial discussion about how to enhance the integration of tendon and bone through biological methods. Stem cells like bone marrow mesenchymal stem cells (MSCs), tendon stem/progenitor cells, synovium-derived MSCs, adipose-derived stem cells, or periosteum-derived periosteal stem cells can self-regenerate and potentially differentiate into different cell types, which have been widely used in tissue repair and regeneration. Thus, we concentrate in this review on the current circumstances of tendon-bone healing using stem cell therapy.

Effects of purified exosome product on rotator cuff tendon-bone healing in vitro and in vivo

Exosomes have multiple therapeutic targets, but the effects on healing rotator cuff tear (RCT) remain unclear. As a circulating exosome, purified exosome product (PEP) has the potential to lead to biomechanical improvement in RCT. Here, we have established a simple and efficient approach that identifies the function and underlying mechanisms of PEP on cell-cell interaction using a co-culture model in vitro. In the in vivo trial, adult female Sprague-Dawley rats underwent unilateral surgery to transect and repair the supraspinatus tendon to its insertion site with or without PEP. PEP promoted the migration and confluence of osteoblast cells and tenocytes, especially during direct cell-cell contact. Expression of potential genes for RCT in vitro and in vivo models were consistent with biomechanical tests and semiquantitative histologic scores, indicating accelerated strength and healing of the RC in response to PEP. Our observations suggest that circulating exosomes provide an effective option to improve the healing speed of RCT after surgical repair. The regeneration of enthesis following PEP treatment appears to be related to a mutually reinforcing relationship between direct cell-cell contact and PEP activity, suggesting a dual approach to the healing process.

Preparation of Silk Fibroin Nanofiber Scaffold and Its Application in Tendon-Bone Healing and Sports Rehabilitation

ABSTRACTIn this work, polylactic acid/polycaprolactone/silk fibroin (PLA/PCL/SF) nanofiber scaffolds with different mass ratios were prepared by electrospinning technology. The morphology and structure of the nanofiber scaffold were characterized with the scanning electron microscope (SEM), and its porosity and adsorption were tested using the Fourier transform infrared spectrometer (FTIR). 24 New Zealand white rabbits were rolled into control group (n = 8, with autologous tendons) and experimental group (n = 16) randomly. The PLA/PCL/SF nanofiber scaffolds were adopted to wrap autologous tendons to establish extra-articular models. Tendon-bone healing was evaluated six weeks after surgery through histological and biomechanical tests, and the related gene expressions in tissue cells were detected. It turned out that mass ratio of PLA/PCL and SF components had a considerable impact on the morphology of the nanofiber scaffold. The surface of nanofiber with a mass ratio of 3:1 was distributed with dense pores. As the content of SF increased, the porosity and adsorption of the nanofiber scaffold gradually decreased. Moreover, the experimental results suggested that the addition of SF improved the hydrophilicity of PLA/PCL/SF scaffold, which was beneficial to the adhesion and proliferation of NIH/3T3 (a mouse embryonic fibroblast cell line established by the National Institutes of Health (NIH)). In addition, histological observation results showed that the width of the tendon-bone interface (TBI) of rabbits in control group was still relatively large at the 6th week after the surgery, with poor healing effect and disordered collagen arrangement. The widths of the TBI of the material group and rehabilitation group were substantially narrower relative to that in control group, and the collagen was arranged regularly. It was suggested that the healing effects between tendon and bone in material group and rehabilitation group were accelerated, and the effect in the rehabilitation group was superior to that of material group, indicating that rehabilitation exercise could organize the negative effects of training in postoperative rehabilitation training and promote the healing between tendons and bones.

Arthroscopic Bursa-Augmented Rotator Cuff Repair: A Vasculature-preserving Technique for Subacromial Bursal Harvest and Tendon Augmentation

Rotator cuff repairs are associated with suboptimal outcomes and possibly greater incidence of retears if the biological healing environment is compromised. Strategies to optimize tendon–bone healing include the use of bioinductive scaffolds and regenerative stem cell therapy. The subacromial bursa has been shown to have significant pluripotent stem cell potency for tendon healing and has the advantage of easy accessibility and no added cost. However, a reproducible surgical technique for bursal mobilization, harvest, and vascularity preservation has not been described. We describe our technique for vasculature-preserving bursal mobilization and harvest of the entire posterosuperior and lateral subacromial bursa, and its use in rotator cuff repair augmentation is presented. The technique involves mobilization of the bursa as a continuous layer by maintain its medial and lateral vascularity. The bursa is advanced laterally, and the “vascular bursal duvet” and cuff tendons are repaired together as a tendon–bursa unit.

Surface modification of the simvastatin factor-loaded silk fibroin promotes the healing of rotator cuff injury through β-catenin signaling.

Rupture of the rotator cuff is a common injury of the shoulder joint in sports professionals. In addition, research on repair of the rotator cuff has gained popularity over the recent years. Given the high rate of re-tear after surgery, it is necessary to design and prepare biodegradable materials with good mechanical properties, for the management of the condition. Consequently, the present study conducted surface modification of the simvastatin factor-loaded silk fibroin for the repair of chronic rotator cuff injury in SD rats. The in vitro experiments were analyzed through scanning electron microscopy and the water contact angle. Additionally, the CCK-8 assay was used to observe the effect of the intervention on the proliferation of BMSCs. Moreover, the osteogenic differentiation of BMSCs was detected through the ALP and ARS assays while the expression of osteogenic genes was examined using qRT-PCR and Western blot analysis. Furthermore, a model for repairing chronic rotator cuff tears in SD rats was established in vivo. Thereafter, rotator cuff repair and healing were evaluated through HE staining while Masson and Sirius staining was used to detect the collagen formation ratio. Additionally, the study analyzed the mechanism underlying the effect of simvastatin-loaded silk fibroin. The results showed that the simvastatin-loaded silk fibroin membrane had better biocompatibility and the in vitro experiments confirmed that it could promote the proliferation and osteogenic differentiation of BMSCs. In addition, the in vivo HE staining experiments similarly confirmed that it could enhance tendon bone healing and alleviate inflammation in chronic rotator cuff injuries. On the other hand, Masson and Sirius staining showed that the simvastatin-loaded silk fibroin could promote the formation of collagen. Further analysis also revealed that it could promote the osteogenic differentiation of BMSCs by activating the β-catenin signaling pathway. In general, these findings suggested that surface modification of the simvastatin factor-loaded silk fibroin was a potential means of improving the healing of rotator cuff injuries and can be implemented in clinical practice in future.

Effect of Freshly Isolated Bone Marrow Mononuclear Cells and Cultured Bone Marrow Stromal Cells in Graft Cell Repopulation and Tendon-Bone Healing after Allograft Anterior Cruciate Ligament Reconstruction.

Graft cell repopulation and tendon-bone tunnel healing are important after allograft anterior cruciate ligament reconstruction (ACLR). Freshly isolated bone marrow mononuclear cells (BMMNCs) have the advantage of short isolation time during surgery and may enhance tissue regeneration. Thus, we hypothesized that the effect of intra-articular BMMNCs in post-allograft ACLR treatment is comparable to that of cultured bone marrow stromal cells (BMSCs). A rabbit model of hamstring allograft ACLR was used in this study. Animals were randomly assigned to the BMMNC, BMSC, and control groups. Fresh BMMNCs isolated from the iliac crest during surgery and cultured BMSCs at passage four were used in this study. A total of 1 × 107 BMMNCs or BMSCs in 100 µL phosphate-buffered saline were injected into the knee joint immediately after ACLR. The control group was not injected with cells. At two and six weeks post operation, we assessed graft cell repopulation with histological and cell tracking staining (PKH26), and tendon-bone healing with histological micro-computed tomography and immunohistochemical analyses for collagen I and monocyte chemoattractant protein-1 (MCP1). At two weeks post operation, there was no significant difference in the total cell population within the allograft among the three groups. However, the control group showed significantly higher cell population within the allograft than that of BM cell groups at six weeks. Histological examination of proximal tibia revealed that the intra-articular delivered cells infiltrated into the tendon-bone interface. Compared to the control group, the BM cell groups showed broader gaps with interfacial fibrocartilage healing, similar collagen I level, and higher MCP1 expression in the early stage. Micro-CT did not reveal any significant difference among the three groups. BMMNCs and BMSCs had comparable effects on cell repopulation and interfacial allograft-bone healing. Intra-articular BM cells delivery had limited benefits on graft cell repopulation and caused higher inflammation than that in the control group in the early stage, with fibrocartilage formation in the tendon-bone interface after allograft ACLR.

Suture technique for rotator cuff tears' repair under arthroscopic

Shoulder arthroscopic as a conventional method usually is applied to repair rotator cuff tears. In clinical, plenty single-row, double-row and transosseous tunnels suture technique are performed, but the ideal suture technique for rotator cuff repair is not found. Compared with single-row, double-row has better strength in biomechanics property. As the two best suture technique among the single-row, massive cuff stitch and modified Mason-Allen suture have the strongest biomechanics property. Clinical trials indicate that double-row could improve healing rates, but there are no significant difference in clinical outcome functional scores. Transosseous tunnel techniques possess a better bio-mechanic property, which could improve regional micro-environment and induce tendon-bone healing. Transosseous tunnel techniques are better for small to media size rotator cuff tears and osteoporosis patient. The author suggest that optimal rotator cuff repair technique should performed according to skill of performer and individual of patient by analysing bio-mechanic properties, clinical outcome, operative complexity and patient situation. The technique should follow simple opertaion, rapid, less trauma, stable fixation and utility to perform.

Conditioned medium of human bone marrow-derived stem cells promotes tendon-bone healing of the rotator cuff in a rat model

Rotator cuff repair is a common surgery in sports medicine. During the surgery, torn tendon was re-fixed onto the bony surface. The majority of patients gain good results. However, re-tear occurs in some patients. The reason under this phenomenon is that the normal tendon-bone enthesis cannot be reconstructed. In order to strengthen the tendon-bone healing and promote enthesis regeneration, numerous manners are tested, among which stem cell related therapies are preferred. Stem cells, due to the ability of multi-lineage differentiation, are widely used in regenerative medicine. However, safety and ethics concerns limit its clinical use. Recent studies found that it is the secretome of stem cells that is biologically effective. On ground of this, we, in the current study, collected the conditioned medium of human bone marrow-derived stem cells (hBMSC-CM) and tested whether this acellular method could promote tendon-bone healing in a rat model of rotator cuff repair. By using histological, radiological, and biomechanical methods, we found that hBMSC-CM promoted tendon-bone healing of the rat rotator cuff. Then, we noticed that hBMSC-CM exerted an impact on macrophage polarization both in vivo and in vitro by inhibiting M1 phenotype and promoting M2 phenotype. Further, we proved that the benefit of hBMSC-CM on tendon-bone healing was related to its regulation on macrophage. Finally, we proved that, hBMSC-CM influenced macrophage polarization, which was, at least partially, related to Smad2/3 signaling pathway. Based on the experiments above, we confirmed the benefit of hBMSC-CM on tendon-bone healing, which relied on its immune-regulative property. Considering the accessibility and safety of acellular hBMSC-CM, we believe it is a promising candidate clinically for tendon-bone healing.

Vitamin C in orthopedic practices: Current concepts, novel ideas, and future perspectives

Vitamin C (ascorbic acid), is an important antioxidant that has been applied broadly in the field of orthopaedics. Current research on vitamin C examines the molecule's role in bone and tendon physiology, as well as joint replacement and Postoperative pain. Most laboratory and human studies associate the use of vitamin C with improved bone health and tendon healing. Recent literature moderately supports the use of vitamin C to improve functional outcomes, decreased postoperative pain, and prevent complex regional pain syndrome following orthopaedic procedures. The perioperative use of vitamin C in patients undergoing joint replacement surgery and anterior cruciate ligament reconstruction is still under investigation. Overall, there is need for high-quality human trials to confirm whether vitamin C can potentiate the outcomes of orthopaedic procedures and to determine optimal dosage and means of administration to maximize its proposed benefits. The purpose of this review was to summarize the application of vitamin C in orthopaedic practices and to identify potential areas for future study.

Biological Mechanism of Extracorporeal Shock Wave Combined with Platelet-Rich Plasma on the Healing of Reconstructed Tendon Bone in a Rabbit Model of Rotator Cuff Tear

To investigate the biological mechanism of the effect of extracorporeal shock wave combined with plateletrich plasma on the healing of reconstructed tendon bone in a rabbit model of rotator cuff tear. 40 New Zealand white rabbits aged 4-5 mo were selected, 32 rabbits were randomly selected and each rabbit was executed at 4-8 w postoperatively and these rabbits were randomly divided into control group, shockwave group, platelet-rich plasma group and shockwave+platelet-rich plasma group. The tendon bone healing site was observed at 2, 4 and 8 w after surgery and the content of transforming growth factor beta 1 and basic fibroblast growth factor were measured by reverse transcription-polymerase chain reaction and western blot, while the biomechanical test was performed on the tendon bone healing specimens. The results showed that the content of neovascularization at the tendon-bone interface at 4 w and 8 w was significantly increased in shockwave, platelet-rich plasma and shockwave+platelet-rich plasma groups. The basic fibroblast growth factor and transforming growth factor beta 1 messenger RNA and protein expression tended to increase after surgery in all four groups and the levels in shockwave, plateletrich plasma and shockwave+platelet-rich plasma groups was significantly increased, while the highest expression in shockwave+platelet-rich plasma group. The maximum load force of the 3 experiment groups was all significantly increased. Besides, the maximum tensile distance was significantly longer in shockwave+platelet-rich plasma group. The combination of extracorporeal shockwave and plateletrich plasma showed optimal performance in the tensile performance of the supraspinatus tendon-bone combination, the maturity of the tendon-bone interface and the content of growth factors that promote the healing of the tendon bone, indicating that the combination of extracorporeal shock wave and plateletrich plasma can promote the healing process of the tendon bone after rotator cuff tears and improve its strength and ultimate load.

Clinical Effect of PRP with DPASB on Full-Thickness Rotator Cuff Tears and Its Role in VAS, SST, and Constant Scores of Patients.

The aim of the study is to probe the effects of platelet-rich plasma (PRP) plus double-row anchor suture bridge (DRASB) under shoulder arthroscopy on the postoperative VAS, SST and Constant scores, rotator cuff tendonbone healing, and re-tear of patients with full-thickness rotator cuff tear (RCT). A total of 60 patients with full-thickness RCT treated in our institution from August 2019 to January 2020 were picked and assigned to either group A (n = 30) or group B (n = 30) on a voluntary basis. Group B received DRASB under shoulder arthroscopy, whereas group A underwent DRASB under shoulder arthroscopy plus PRP. We compared the curative effects of both groups. Week 2, 4, 8, 12 after surgery and 6 months after surgery, VAS scores of patients in both groups declined saliently, whereas SST and Constant scores elevated, and the decrease/increase amplitude of patients in group A was sharply higher than that in group B (p < 0.05). At T2 and T3, abduction 90° external rotation, abduction 90° internal rotation, abduction and anteflexion in both groups increased strikingly, and group A harbored a brilliantly higher increase than group B (p < 0.05). At T2 and T3, serum NO and IL-6 contents were prominently dwindled in both groups, and group A held a plainly higher decrease than group B (p < 0.05). At T3, in comparison to group B, the rotator cuff tendonbone healing rate and quality of life scores in group A were higher (p < 0.05), whereas retear rate was dramatically lower (p < 0.05). DRASB under shoulder arthroscopy plus PRP therapy can blatantly meliorate the curative effect of patients with full-thickness tear, improve the shoulder joint function and tendonbone healing rate, reduce the postoperative pain degree and the incidence of retear, and can be more broadly promoted and applied clinically.

Bone marrow mesenchymal stem cell-derived exosomes promote rotator cuff tendon-bone healing by promoting angiogenesis and regulating M1 macrophages in rats

BackgroundRotator cuff tears (RCTs) often require reconstructive surgery. Tendon-bone healing is critical for the outcome of rotator cuff reconstruction, but the process of tendon-bone healing is complex and difficult. Mesenchymal stem cells (MSCs) are considered to be an effective method to promote tendon-bone healing. MSCs have strong paracrine, anti-inflammatory, immunoregulatory, and angiogenic potential. Recent studies have shown that MSCs achieve many regulatory functions through exosomes. The purpose of this study was to explore the role of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) in tendon-bone healing.MethodsOur study found that BMSC-Exos promote the proliferation, migration, and angiogenic tube formation of human umbilical vein endothelial cells (HUVECs). The mechanism by which BMSC-Exos achieve this may be through the regulation of the angiogenic signaling pathway. In addition, BMSC-Exos can inhibit the polarization of M1 macrophages and inhibit the secretion of proinflammatory factors by M1 macrophages. After rotator cuff reconstruction in rats, BMSC-Exos were injected into the tail vein to analyze their effect on the rotator cuff tendon-bone interface healing.ResultsIt was confirmed that BMSC-Exos increased the breaking load and stiffness of the rotator cuff after reconstruction in rats, induced angiogenesis around the rotator cuff endpoint, and promoted growth of the tendon-bone interface.ConclusionBMSC-Exos promote tendon-bone healing after rotator cuff reconstruction in rats by promoting angiogenesis and inhibiting inflammation.

Magnesium-pretreated periosteum for promoting bone-tendon healing after anterior cruciate ligament reconstruction

Periosteum can improve tendon-bone healing when applied to wrap the tendon graft in both animal studies and clinical trials. As magnesium (Mg) ions can significantly elevate the levels of relevant cytokines involving in the osteogenic differentiation of periosteum-derived stem cells, the Mg-pretreated periosteum may be an innovative approach for enveloping the tendon graft. To test this hypothesis, we compared the effects of Mg-pretreated periosteum (M − P) and the stainless steel (SS)-pretreated periosteum (SS–P) in ACL reconstruction. We firstly found that the released Mg ions from the Mg implants were partially accumulated in periosteum, resulting in higher Mg/Ca ratio in the M − P compared to the SS-P. Additionally, the M − P showed significantly higher expression levels of calcitonin gene-related peptide (CGRP) and periostin than the SS-P due to the decrease in Cathepsin K (CTSK). Elevation of CGRP and periostin was beneficial for the osteogenic differentiation of periosteum-derived stem cells. More importantly, we demonstrated that the M − P remarkably increased the formation of fibrocartilage at the interface between the periosteum and tendon. Collectively, M − P group demonstrated significantly prevented peri-tunnel bone loss, more osseous ingrowth into the tendon graft and higher maximum load to failure as compared to the SS-P group. In summary, our study warrants further investigations for translating the current proof-of-concept findings to optimize the delivery of CGRP, periostin, and cells as novel practical therapeutic strategy for enhancing tendon-bone interface healing in patients undergoing ACL reconstruction.

Comparison of tendon-bone healing between a newly developed ultrasound device and the conventional metallic drill in a rabbit MCL reconstruction model

BackgroundLigament reconstructive surgeries demand tunnel creation using an over-drilling technique, though this technique has some problems such as metallic particle liberation or difficulties in tunnel creation other than circular cross-section. Recently, a new ultrasound (US) device for bone excavation to overcome these problems was developed. This study aimed to compare the tendon-bone healing in tunnels created using the new US device to that created using the conventional drill in a rabbit model. MethodsA total of 72 rabbits underwent a reconstruction for the anterior half of the medial collateral ligament (MCL) using a half of the patellar tendon. For the femoral tunnel creation, a new US device was used in 36 rabbits (US group), while a conventional metallic drill was used for the remaining 36 rabbits (DR group). At 4, 8, and 12 weeks postoperatively, biomechanical (n = 10) and histological (n = 2) evaluations were performed. ResultsThe ultimate failure load was almost equivalent between the US and DR groups at each period (US/DR; 4 weeks, 50.0 ± 12.8 N/43.4 ± 18.9 N, p = 0.62; 8 weeks, 78.6 ± 11.5 N/77.3 ± 29.9 N, p = 0.92; and 12 weeks: 98.9 ± 33.5 N/102.2 ± 38.3 N, p = 0.80). Pull-out failure from the femoral tunnel was only observed in two rabbits in the US group and one rabbit in the DR group at 4 weeks postoperatively. At 8 and 12 weeks, all specimens had a mid-substance tear. The collagen fiber continuity between tendon and bone occurred 8 weeks postoperatively in both groups and no histological difference was recognized throughout the evaluation period. ConclusionsThe tunnels created using the new US device and the conventional drill had equivalent biomechanical and histological features in tendon-bone healing. The bone excavation technology by the new US device may be applicable in ligament reconstructive surgeries.

Tissue-Engineered Decellularized Allografts for Anterior Cruciate Ligament Reconstruction.

Anterior cruciate ligament (ACL) reconstruction with allografts is limited by high immunogenicity, poor cellularization, and delayed tendon-bone healing. Decellularized tendons (DAs) have been used as bioscaffolds to reconstruct ligaments with variable success. In the study, four kinds of decellularized allogeneic hamstring tendons were prepared and their microstructure and cytocompatibility were examined in vitro. The results showed that decellularized allografts neutralized by 5% calcium bicarbonate had typical reticular and porous microstructures with optical cytocompatibility. Tissue-engineering decellularized allografts (TEDAs) were prepared with the selected decellularized allografts and tendon stem/progenitor cells and used for ACL reconstruction in a rabbit model. Histological staining showed that the TEDAs promoted cellular infiltration and new vessel formation significantly and improved tendon-bone healing moderately compared to decellularized allografts. Better macroscopic scores and biomechanical results were observed in TEDA groups, but there were no significant differences between DA and TEDA groups at months 1, 2, and 3 postoperatively. Immunohistochemical data showed that the tissue-engineering decellularized allografts enhanced the expression of collagen I at each timepoint and collagen III at months 1 and 2. ELISA analysis showed that the tissue-engineering decellularized allografts reduced the secretion of IgE and IL-1β within 1 month and promoted the secretion of IL-2, IL-4, IL-10, and IL-17 after 1 month. The results showed that tissue-engineering decellularized allografts strengthened intra-articular graft remodeling significantly and provided moderate improvements in tendon-bone healing by creating more suitable immune responses than decellularized allografts. The study revealed that tissue-engineering decellularized allografts as a promising option for ACL reconstruction could achieve more favorable outcomes.

Progress on improving tendon-to-bone healing for the enthesis of rotator cuff

Rotator cuff repair is a common treatment for rotator cuff tear, which could effectively relieve shoulder pain and improve shoulder movement, and the incidence of rotator cuff retear after rotator cuff repair is still high. The main reason is poor tendon-bone healing in rotator cuff enthesis after rotator cuff repair and could not recover the original histological structure and biomechanical properties. Therefore, the key to solve the problem is how to effectively improve the healing of tendon bone at the end of rotator cuff. With the in-depth study of rotator cuff enthesis, various treatments have made great progress on improving tendon to bone healing of rotator cuff. Our study will discuss the researchprogress on tendon to bone healing of rotator cuff in recent years from three following aspects to provide some guidance for the clinical treatment of rotator cuff tear:the factors affecting the tendon to bone healing of rotator cuff, the recovery of tendon to bone interface promoting the tendon to bone healing of rotator cuff and the application of tissue engineering in tendon to bone healing.

Arthroscopic reconstruction of anterior cruciate ligament with autologous ipsilateral peroneus longus tendon

To investigate the effectiveness of anterior cruciate ligament (ACL) reconstruction with the autologous ipsilateral peroneus longus tendon (PLT) under arthroscopy. A retrospective study was conducted on 35 patients with ACL rupture who underwent ACL reconstruction with autologous ipsilateral PLT under arthroscopy between October 2017 and October 2018. There were 19 males and 16 females with an average age of 43.4 years (range, 18-60 years), with 20 cases of left knee and 15 cases of right knee. The causes of injury included traffic accident in 14 cases, falling injury in 13 cases, and sports injury in 8 cases. The time from injury to operation ranged from 3 to 9 days (mean, 4.7 days). The patients suffered from swelling, pain, and limited mobility of knee joint before operation. The anterior drawer test, Lachman test, and pivot-shift test were positive before operation, whereas MRI was taken to confirm the ACL rupture. After operation, the patients were followed up every 3 months until the knee joint's function returned to normal. MRI and X-ray films were used to observe the tendon-bone healing as well as the position of Endobutton suspension plate and hollow nail. The anterior drawer test, Lachman test, and pivot-shift test were conducted to observe the improvement of knee joint mobility. The functional improvements were evaluated by the International Knee Documents Committee (IKDC) score, Lysholm score, knee injury and osteoarthritis (KOOS) score. All the 35 patients were followed up 12-18 months, with an average of 14.2 months. The incisions healed by first intention, and no complications such as infection, joint stiffness, and rerupture occurred. Postoperative anterior drawer test, Lachman test, and pivot-shift test turned to be negative of all patients. MRI showed that the ACL was continuous, and the tendon-bone in the distal femur tunnel and proximal tibia tunnel recovered well after operation. X-ray films showed that the positions of Endobutton suspension plate and hollow nail were stable. The IKDC, Lysholm, and KOOS scores at 3, 6, and 12 months after operation were significantly improved when compared with those before operation, and the scores were further improved with time after operation ( P<0.05). For patients with ACL rupture, ACL reconstruction with the autologous ipsilateral PLT under arthroscopy has satisfactory effectiveness of quick recovery, good function, and great stability.

Repair of Tendon Disruption Using a Novel Synthetic Fiber Implant in Dogs and Cats: The Surgical Procedure and Three Case Reports.

Surgical management of tendon rupture is challenging. One concern is to provide adequate tensile strength to prevent distraction during weight-bearing and gap formation following repair, associated with an increased risk of repair failure. Additional challenges may arise from the nature or the chronicity of the lesion. In the event of avulsion, when the tendon is torn off at the bone insertion, its reinsertion on the bone is generally difficult and may even be impossible in the presence of an avulsion fracture, especially when the bone fragment is too small or fragmented. Repair management is also complicated in chronic cases, as degeneration of the tendon may lead to excessive scar tissue formation, tendon retraction, and muscle atrophy, resulting in a large gap and inadequate tissue for reconstruction. The authors describe the surgical procedure for implanting a novel implant, illustrated by three characteristic clinical cases: (1) an acute Achilles tendon avulsion; (2) a chronic patellar tendon rupture; and (3) a chronic avulsion fracture of the triceps tendon. In these three cases, complete recovery of the function was observed at the last clinical evaluation (6 or 8 months), and no complication was noted. A splinted dressing (6 to 8 weeks) was used successfully in two cases. A resin cast (8 weeks) was preferred in case 1, a very active dog. In conclusion, this novel implant represents a simple procedure for the effective repair of chronic tendon rupture, as well as an effective tendon reinsertion on the bone and adequate support for bone tendon healing in the treatment of tendon avulsion, even in cases of fragmented bone fracture. The thinness of the implant facilitates its insertion into the native tendon, while the bone-screw-implant interface provides immediate and lasting mechanical support. This may facilitate the healing process and potentially shorten the period of immobilization.

Clinical study on reconstruction of posterior cruciate ligament with platelet rich plasma combined with 3-strand peroneus longus tendons

To investigate the effectiveness of the reconstruction of posterior cruciate ligament (PCL) with platelet rich plasma (PRP) and 3-strand peroneal longus tendons under arthroscope. Between June 2014 and December 2017, 58 patients with PCL rupture were randomly divided into two groups: the trial group (PRP assisted reconstruction of 3-strand peroneal longus tendons) and the control group (4-strand hamstring tendon reconstruction alone), 29 cases in each group. There was no significant difference in gender, age, injury side, Kellgren-Lawrence grade, time from injury to operation, and preoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, International Knee Documentation Committee (IKDC) score, Lysholm score between the two groups ( P>0.05). Before operation, at 3 months and 12 months after operation, the IKDC score and Lysholm score of the two groups were recorded to evaluate the knee joint function, AOFAS ankle-hindfoot score was used to evaluate ankle function; KT-2000 examination (knee flexion of 90°, 30 lbs) was used to evaluate the difference of bilateral knee joint posterior relaxation at 12 months after operation, and MRI was used to evaluate ligament reconstruction; CT was used to evaluate the bone tunnel expansion of femur and tibia at 3 months and 12 months after operation. The operation was completed successfully in both groups, there was no complication in the donor tendon area. All the incisions healed by first intention. All the patients were followed up for more than 1 year. The follow-up time of the trial group was 13-17 months, with an average of 15.0 months; that of the control group was 15-20 months, with an average of 15.4 months. At 3 and 12 months after operation, there was no significant difference in AOFAS ankle-hindfoot score when compared with preoperative score and between the two groups ( P>0.05). At 3 and 12 months after operation, the IKDC score and Lysholm score of the two groups were significantly improved, and further improvement was found at 12 months when compared with at 3 months ( P<0.05); the scores in the trial group were significantly better than those of the control group ( P<0.05). At 12 months after operation, the difference of the posterior relaxation of the bilateral knees in the trial group was less than 5 mm in 27 cases, 6-10 mm in 2 cases; in the control group was less than 5 mm in 20 cases, 6-10 mm in 6 cases, and >10 mm in 3 cases; the difference between the two groups was not significant ( Z=0.606, P=0.544). At 12 months after operation, MRI of knee joint showed that all patients had good PCL graft. The MRI score of the trial group was better than that of the control group ( t=2.425, P=0.019). CT examination at 3 and 12 months after operation showed that the bone tunnel expansion of femur and tibia in the trial group were significantly better than those in the control group ( P<0.05). PRP combined with 3-stand peroneal longus tendons can significantly improve the function and stability of knee joint, effectively promote graft remodeling, and promote tendon bone healing, reduce the expansion of bone tunnel. The effectiveness is satisfactory.

Biomechanical, histologic, and molecular characteristics of graft-tunnel healing in a murine modified ACL reconstruction model.

SummaryPurposeThe purpose of our study was to introduce and validate a metal-free, reproducible and reliable mouse model of anterior cruciate ligament (ACL) reconstruction (ACLR) surgery as an effective tool for a better understanding of molecular mechanisms of graft-tunnel healing after ACLR.MethodsA total of 150 C57BL/6 mice were randomly allocated into five Groups: Group 1 (mice with intact ACL), Group 2–4 (mice underwent modified ACLR surgery and sacrificed 1-, 2-, and 4-weeks after surgery), and Group 5 (mice underwent unmodified ACLR surgery and sacrificed 4 weeks after surgery). Micro-computed tomography (CT), biomechanical histological as well as immunohistochemical (IHC) analyses were performed to characterize the modified ACLR.ResultsMicro-CT analysis demonstrated there is a non-significant increase in BV/TV and BMD of the bone tunnel during the tendon-to-bone healing following ACLR. Biomechanical tests showed that the mean load-to-failure forces of Group 3 and 4 are equal to 31.7% and 46.0% of that in Group 1, while the stiffness was 33.1% and 57.2% of that of Group 1, respectively. And no obvious difference in biomechanical parameters was found between Group 4 and 5. Histological analysis demonstrated that formation of fibrovascular tissue in the tibial tunnel and aperture in Groups 4 and 5 and direct junction appeared between tendon graft and tunnel both in Groups 4 and 5. IHC results showed that there are gradually enhanced expression of Patched1, Smoothened and Gli2 concomitant with decreased Gli3 protein in the tendon-bone interface during the tendon-bone healing process.ConclusionWe introduced a metal-free, reproducible and reliable mouse model of ACLR compared to the unmodified ACLR procedure, and characterized the expression pattern of key molecules in Ihh signaling during the graft healing process.The translational potential of this articleIn the present study we introduced and validated, for the first time, a metal-free, reproducible and reliable ACLR mouse model, which could be used to investigate the detailed molecular mechanisms of graft-tunnel healing after ACLR. We also explored new strategies to promote the healing of tendon-to-bone integration.