Extracorporeal shockwave enhanced regeneration of fibrocartilage in a delayed tendon-bone insertion repair model

Extracorporeal shockwave therapy for degenerative meniscal tears results in a decreased T2 relaxation time and pain relief: An exploratory randomized clinical trial

PURPOSE

The optimal management of degenerative meniscal tears remains controversial. Extracorporeal shockwave therapy (ESWT) has been shown to promote tissue repair in both preclinical and clinical studies; however, its effect on degenerative meniscal tears remains unknown. This study aimed to examine whether ESWT improves meniscal degeneration.

METHODS

This randomized trial was conducted between 2020 and 2022 and involved patients with degenerative medial meniscal tears. Patients were allocated to receive either focused ESWT (0.25 mJ/mm2, 2000 impulses, 3 sessions with a 1-week interval) or sham treatment. Patients were evaluated using magnetic resonance imaging (MRI) before treatment and at 12 months after treatment. The primary endpoint was improvement in meniscal degeneration, as assessed by the change in T2 relaxation time from baseline on MRI T2 mapping. Knee pain and clinical outcomes were also examined at the same time.

RESULTS

Of 29 randomized patients, 27 patients (mean age 63.9 ± 8.7 years; females 37%; ESWT group 14 patients; control group 13 patients) were included in the final analysis. At 12 months postintervention, patients in the ESWT group showed a greater decrease in the T2 relaxation time (ESWT group -2.9 ± 1.7 ms vs. control group 1.0 ± 1.9 ms; p < 0.001) and had less knee pain (p = 0.04). The clinical outcomes at 12 months post-treatment were not statistically significant. No adverse events were reported.

CONCLUSION

ESWT decreased the T2 relaxation time in the meniscus at 12 months post-treatment. ESWT also provided pain relief, but no differences were observed in clinical outcomes.

LEVEL OF EVIDENCE

Level II.

A rabbit osteochondral defect (OCD) model for evaluation of tissue engineered implants on their biosafety and efficacy in osteochondral repair

Osteochondral defect (OCD) is a common but challenging condition in orthopaedics that imposes huge socioeconomic burdens in our aging society. It is imperative to accelerate the R&D of regenerative scaffolds using osteochondral tissue engineering concepts. Yet, all innovative implant-based treatments require animal testing models to verify their feasibility, biosafety, and efficacy before proceeding to human trials. Rabbit models offer a more clinically relevant platform for studying OCD repair than smaller rodents, while being more cost-effective than large animal models. The core-decompression drilling technique to produce full-thickness distal medial femoral condyle defects in rabbits can mimic one of the trauma-relevant OCD models. This model is commonly used to evaluate the implant's biosafety and efficacy of osteochondral dual-lineage regeneration. In this article, we initially indicate the methodology and describe a minimally-invasive surgical protocol in a step-wise manner to generate a standard and reproducible rabbit OCD for scaffold implantation. Besides, we provide a detailed procedure for sample collection, processing, and evaluation by a series of subsequent standardized biochemical, radiological, biomechanical, and histological assessments. In conclusion, the well-established, easy-handling, reproducible, and reliable rabbit OCD model will play a pivotal role in translational research of osteochondral tissue engineering.

Single-Dose Radial Extracorporeal Shock Wave Therapy Modulates Inflammation During Meniscal Tear Healing in the Avascular Zone

BACKGROUND

Extracorporeal shock wave therapy (ESWT) promotes tissue healing by modulating inflammation, which has implications for meniscal tear healing in the avascular zone.

PURPOSE

To evaluate the effects of a single dose of radial ESWT on the healing process and inflammation of the meniscus and knee joints after meniscal tears in the avascular zone.

STUDY DESIGN

Controlled laboratory study.

METHODS

Avascular tears were induced in the medial meniscus (MM) of 72 Sprague-Dawley rats. One week postoperatively, the rats received a single session of radial ESWT with a Power+ handpiece (ESWT group; n = 36) or with a fake handpiece (sham-ESWT group; n = 36). The rats were then euthanized at 2, 4, or 8 weeks postoperatively. The MMs were harvested for analysis of healing (hematoxylin-eosin, safranin O-Fast Green, and collagen type 2 staining) and inflammation (interleukin [IL]-1β and IL-6 staining). Lateral menisci and synovia were obtained to evaluate knee joint inflammation (enzyme-linked immunosorbent assay of IL-1β and IL-6). Cartilage degeneration was assessed in the femurs and tibial plateaus using safranin O-Fast Green staining.

RESULTS

The ESWT group showed significantly better meniscal healing scores than the sham-ESWT group at 4 (P = .0066) and 8 (P = .0050) weeks postoperatively. The IL-1β level was significantly higher in the sham-ESWT group than in the ESWT group at 2 (MM: P = .0009; knee joint: P = .0160) and 8 (MM: P = .0399; knee joint: P = .0001) weeks. The IL-6 level was significantly lower in the sham-ESWT group than in the ESWT group at 2 (knee joint: P = .0184) and 4 (knee joint: P = .0247) weeks but higher at 8 weeks (MM: P = .0169; knee joint: P = .0038). The sham group had significantly higher osteoarthritis scores than the ESWT group at 4 (tibial plateau: P = .0157) and 8 (femur: P = .0048; tibial plateau: P = .0359) weeks.

CONCLUSION

A single dose of radial ESWT promoted meniscal tear healing in the avascular zone, modulated inflammatory factors in the menisci and knee joints in rats, and alleviated cartilage degeneration.

CLINICAL RELEVANCE

Radial ESWT can be considered a potential option for improving meniscal tear healing in the avascular zone because of its ability to modulate inflammation.

Strategies to promote tendon-bone healing after anterior cruciate ligament reconstruction: Present and future

At present, anterior cruciate ligament (ACL) reconstruction still has a high failure rate. Tendon graft and bone tunnel surface angiogenesis and bony ingrowth are the main physiological processes of tendon-bone healing, and also the main reasons for the postoperative efficacy of ACL reconstruction. Poor tendon-bone healing has been also identified as one of the main causes of unsatisfactory treatment outcomes. The physiological process of tendon-bone healing is complicated because the tendon-bone junction requires the organic fusion of the tendon graft with the bone tissue. The failure of the operation is often caused by tendon dislocation or scar healing. Therefore, it is important to study the possible risk factors for tendon-bone healing and strategies to promote it. This review comprehensively analyzed the risk factors contributing to tendon-bone healing failure after ACL reconstruction. Additionally, we discuss the current strategies used to promote tendon-bone healing following ACL reconstruction.

Strategies for promoting tendon-bone healing: Current status and prospects

Tendon-bone insertion (TBI) injuries are common, primarily involving the rotator cuff (RC) and anterior cruciate ligament (ACL). At present, repair surgery and reconstructive surgery are the main treatments, and the main factor determining the curative effect of surgery is postoperative tendon-bone healing, which requires the stable combination of the transplanted tendon and the bone tunnel to ensure the stability of the joint. Fibrocartilage and bone formation are the main physiological processes in the bone marrow tract. Therefore, therapeutic measures conducive to these processes are likely to be applied clinically to promote tendon-bone healing. In recent years, biomaterials and compounds, stem cells, cell factors, platelet-rich plasma, exosomes, physical therapy, and other technologies have been widely used in the study of promoting tendon-bone healing. This review provides a comprehensive summary of strategies used to promote tendon-bone healing and analyses relevant preclinical and clinical studies. The potential application value of these strategies in promoting tendon-bone healing was also discussed.

Physical Rehabilitation in Zoological Companion Animals

Animal physical rehabilitation is one of the fast-growing fields in veterinary medicine in recent years. It has become increasingly common in small animal practice and will continue to emerge as an essential aspect of veterinary medicine that plays a vital role in the care of animals with physical impairments or disabilities from surgery, injuries, or diseases.1 This is true now more than ever because of the increasing advances in lifesaving treatments, the increased lifespan of companion animals, and the growth of chronic conditions, of which many are associated with movement disorders. The American Association of Rehabilitation Veterinarians (AARV) defines APR as "the diagnosis and management of patients with painful or functionally limiting conditions, particularly those with injury or illness related to the neurologic and musculoskeletal systems." Rehabilitation not only focuses on recovery after surgical procedures but also on improving the function and quality of life in animals suffering from debilitating diseases such as arthritis or neurologic disorders. The overall goal of APR is to decrease pain, reduce edema, promote tissue healing, restore gait and mobility to its prior activity level, regain strength, prevent further injury, and promote optimal quality of life. Typically, a multimodal approach with pharmaceutical and nonpharmaceutical interventions is used by APR therapists to manage patients during their recovery. The purpose of this article aims to provide knowledge and guidance on physical rehabilitation to help veterinarians in the proper return of their patients with ZCA safely after injury and/or surgery.

The Effects of the Exposure of Musculoskeletal Tissue to Extracorporeal Shock Waves

Extracorporeal shock wave therapy (ESWT) is a safe and effective treatment option for various pathologies of the musculoskeletal system. Many studies address the molecular and cellular mechanisms of action of ESWT. However, to date, no uniform concept could be established on this matter. In the present study, we perform a systematic review of the effects of exposure of musculoskeletal tissue to extracorporeal shock waves (ESWs) reported in the literature. The key results are as follows: (i) compared to the effects of many other forms of therapy, the clinical benefit of ESWT does not appear to be based on a single mechanism; (ii) different tissues respond to the same mechanical stimulus in different ways; (iii) just because a mechanism of action of ESWT is described in a study does not automatically mean that this mechanism is relevant to the observed clinical effect; (iv) focused ESWs and radial ESWs seem to act in a similar way; and (v) even the most sophisticated research into the effects of exposure of musculoskeletal tissue to ESWs cannot substitute clinical research in order to determine the optimum intensity, treatment frequency and localization of ESWT.

The Effects of Three and Six Sessions of Low Energy Extracorporeal Shockwave Therapy on Graft Incorporation and Knee Functions Post Anterior Cruciate Ligament Reconstruction

Introduction

One session of high energy extracorporeal shockwave therapy (ESWT) was found to improve the healing of anterior cruciate ligament (ACL) after reconstruction in animal and human studies. This study investigated the effects of three and six sessions of low energy ESWT on graft incorporation and knee functions post ACL reconstruction in humans.

Materials and methods

Thirty participants with ACL injuries were recruited and assigned equally into three groups with 10 participants per group (n=10). Participants in the control group received physiotherapy alone without low energy ESWT. Participants in the 3ESWT group underwent three sessions of low energy ESWT (one session per week) combined with physiotherapy, and participants in the 6ESWT group received six sessions of low energy ESWT (one session per week) combined with physiotherapy. However, five participants were lost to follow-up. Evaluations of graft incorporation of the tibial tunnel using magnetic resonance (MRI) and Lysholm score were carried out before ACL reconstruction and after six months post ACL reconstruction.

Results

The number of grafts with partial incorporation in the tibia tunnel in 6ESWT was significantly higher compared with the number of grafts with non-incorporation at six months post-operatively, X2 (1, N=9) =5.44, p =0.02. However, there was no significant difference between frequencies of graft incorporation in tibia tunnel in the control and 3ESWT groups, X2 (1, N=7) =3.57, p =0.06 and X2 (1, N=9) =2.78, p =0.10, respectively at 6 months postoperatively. Lysholm scores were significantly higher at 6 months post ACL reconstruction compared to the baseline value for each group (p<0.002, respectively). However, there was no significant difference in the Lysholm score between each group (F = 2.798, p = 0.083).

Conclusions

Six sessions of low energy ESWT improved graft incorporation in the tibial tunnel. Both three and six sessions of low energy of ESWT does not affect the knee function score at six months post ACL reconstruction.

Biodegradable magnesium pins enhanced the healing of transverse patellar fracture in rabbits

Displaced fractures of patella often require open reduction surgery and internal fixation to restore the extensor continuity and articular congruity. Fracture fixation with biodegradable magnesium (Mg) pins enhanced fracture healing. We hypothesized that fixation with Mg pins and their degradation over time would enhance healing of patellar fracture radiologically, mechanically, and histologically. Transverse patellar fracture surgery was performed on thirty-two 18-weeks old female New Zealand White Rabbits. The fracture was fixed with a pin made of stainless steel or pure Mg, and a figure-of-eight stainless steel band wire. Samples were harvested at week 8 or 12, and assessed with microCT, tensile testing, microindentation, and histology. Microarchitectural analysis showed that Mg group showed 12% higher in the ratio of bone volume to tissue volume at week 8, and 38.4% higher of bone volume at week 12. Tensile testing showed that the failure load and stiffness of Mg group were 66.9% and 104% higher than the control group at week 8, respectively. At week 12, Mg group was 60.8% higher in ultimate strength than the control group. Microindentation showed that, compared to the Control group, Mg group showed 49.9% higher Vickers hardness and 31% higher elastic modulus at week 8 and 12, respectively. At week 12, the new bone of Mg group remodelled to laminar bone, but those of the control group remained woven bone-like. Fixation of transverse patellar fracture with Mg pins and its degradation enhanced new bone formation and mechanical properties of the repaired patella compared to the Control group.

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Kirschner wires (K-wire) with tension band wire is widely used fixation implants for repairing of displaced patellar fractures.

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Fixation of patellar fracture with Mg pins enhanced new bone formation and mechanical properties of the repaired patella.

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With a stainless steel tension band wire, Mg pins may be an alternative to K-wire for fixation of patellar fractures.

Abnormal lacuno-canalicular network and negative correlation between serum osteocalcin and Cobb angle indicate abnormal osteocyte function in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a prevalent spinal deformity occurring during peripubertal growth period that affects 1-4% of adolescents globally without clear etiopathogenetic mechanism. Low bone mineral density is an independent and significant prognostic factor for curve progression. Currently, the cause underlying low bone mass in AIS remains elusive. Osteocytes play an important role in bone metabolism and mineral homeostasis, but its role in AIS has not been studied. In the present study, iliac bone tissues were harvested from 21 patients with AIS (mean age of 14.3 ± 2.20 yr old) with a mean Cobb angle of 55.6 ± 10.61° and 13 non-AIS controls (mean age of 16.5 ± 4.79 yr old) intraoperatively. Acid-etched scanning electron microscopy (SEM) images of AIS demonstrated abnormal osteocytes that were more rounded and cobblestone-like in shape and were aligned in irregular clusters with shorter and disorganized canaliculi. Further quantitative analysis with FITC-Imaris technique showed a significant reduction in the canalicular number and length as well as an increase in lacunar volume and area in AIS. SEM with energy-dispersive X-ray spectroscopy analysis demonstrated a lower calcium-to-phosphorus ratio at the perilacunar/canalicular region. Moreover, microindentaion results revealed lower values of Vickers hardness and elastic modulus in AIS when compared with controls. In addition, in the parallel study of 99 AIS (27 with severe Cobb angle of 65.8 ± 14.1° and 72 with mild Cobb angle of 26.6 ± 9.1°) with different curve severity, the serum osteocalcin level was found to be significantly and negatively associated with the Cobb angle. In summary, the findings in this series of studies demonstrated the potential link of abnormal osteocyte lacuno-canalicular network structure and function to the observed abnormal bone mineralization in AIS, which may shed light on etiopathogenesis of AIS.-Chen, H., Zhang, J., Wang, Y., Cheuk, K.-Y., Hung, A. L. H., Lam, T.-P., Qiu, Y., Feng, J. Q., Lee, W. Y. W., Cheng, J. C. Y. Abnormal lacuno-canalicular network and negative correlation between serum osteocalcin and Cobb angle indicate abnormal osteocyte function in adolescent idiopathic scoliosis.

Magnesium (Mg) based interference screws developed for promoting tendon graft incorporation in bone tunnel in rabbits

How to enhance tendon graft incorporation into bone tunnels for achieving satisfactory healing outcomes in patients with anterior cruciate ligament reconstruction (ACLR) is one of the most challenging clinical problems in orthopaedic sports medicine. Several studies have recently reported the beneficial effects of Mg implants in bone fracture healing, indicating the use potential of Mg devices in promoting the tendon graft osteointegration. Here, we developed an innovative Mg-based interference screws for fixation of the tendon graft in rabbits underwent ACLR and investigated the biological role of Mg-based implants in the graft healing. The titanium (Ti) interference screw was used as the control. We demonstrated that Mg interference screw significantly accelerated the incorporation of the tendon graft into bone tunnels via multiscale analytical methods including scanning electronic microscopy/energy dispersive spectrometer (SEM/EDS), micro-hardness, micro-Fourier transform infrared spectroscopy (μFTIR), and histology. Our in vivo study showed that Mg implants enhanced the recruitment of bone marrow stromal stem cells (BMSCs) towards peri-implant bone tissue, which may be ascribed to the upregulation of local TGF-β1 and PDGF-BB. Besides, the in vitro study revealed that higher Mg ions was beneficial to the improvement of capability in cell adhesion and osteogenic differentiation of BMSCs. Thus, the enhancement in cell migration, cell adhesion and osteogenic differentiation of BMSCs may contribute to an improved tendon graft osteointegration in the Mg group. Our findings in this work may further facilitate clinical applications of Mg-based interference screws for enhancing tendon graft-bone junction healing in patients indicated for ACLR.

STATEMENT OF SIGNIFICANCE

How to promote tendon-bone junction healing is one of the major challenging issues for satisfactory clinical outcomes in patients after ACL reconstruction. The improvement of bony ingrowth into the tendon graft-bone interface can enhance the tendon graft osteointegration. In this study, we applied Mg based interference screws to fix the tendon graft in rabbits and found the use of Mg screws could accelerate and significantly increase mineralized matrix formation at the tendon-bone interface in animals when compared to those with Ti screws. We elucidated the mechanism behind the favorable effects of Mg screws on the graft healing in both in vitro and in vivo studies from multiscale technologies. The optimized interface structure and function in Mg group may be ascribed to the improved cell migration capability, enhanced cell adhesion strength and promoted osteogenic differentiation ability of BMSCs under the stimuli of Mg ions degraded from implanted Mg screws. Our findings may help us broaden our thinking in the application potential of Mg interference screws in future clinical trials.

Preliminary investigation of a biological augmentation of rotator cuff repairs using a collagen implant: a 2-year MRI follow-up

BACKGROUND

the inability to restore the normal tendon footprint and limit strains on the repair site are thought to contribute to re-tearing following rotator cuff repair. The purpose of this study was to use a collagen implant to augment rotator cuff repairs through the restoration of the native tendon footprint and the induction of new tissue to decrease overall tendon strain.

METHODS

repairs of full-thickness rotator cuff lesions in 9 adult patients were augmented with a novel collagen implant placed over the bursal surface of the repair. Tendon thickness and footprint anatomy were evaluated using MRI at 3, 6, 12, and 24 months. Clinical results were assessed using standard outcome metrics. Mean follow-up for all patients was 25.8 months.

RESULTS

the implant induced significant new tissue formation in all patients by 3 months. This tissue matured over time and became indistinguishable from the underlying tendon. At 24 months all repairs remained intact and normal footprint anatomy of the tendon was restored in all patients. All clinical scores improved significantly over time.

CONCLUSION

the ability of a collagen implant to induce new host tissue formation and restore the normal footprint anatomy may represent a significant advancement in the biological augmentation and ultimate durability of rotator cuff repairs.

A Comparative Study on the Biomechanical and Histological Properties of Bone-to-Bone, Bone-to-Tendon, and Tendon-to-Tendon Healing: An Achilles Tendon-Calcaneus Model in Goats

BACKGROUND

Surgical repair around the bone-tendon insertion (BTI) may involve bone-to-bone (BB), bone-to-tendon (BT), or tendon-to-tendon (TT) reattachment with varying healing outcome.

HYPOTHESIS

The repair of Achilles tendon-calcaneus (ATC) by reattachment of homogeneous tissue (BB or TT) would heal faster, with respect to tensile properties at the healing complex, than those of reattachment of heterogeneous tissues (BT) over time.

STUDY DESIGN

Controlled laboratory study.

METHODS

Forty-seven adolescent male Chinese goats were divided into BB, BT, and TT groups. Osteotomy of the calcaneus, reattachment of Achilles tendon to the calcaneus after removal of the insertion, and tenotomy of the Achilles tendon were performed to simulate BB, BT, and TT repair, respectively. The ATC healing complexes were harvested at 6, 12, or 24 weeks postoperatively. Mechanical and morphological properties of the healing ATC complexes were assessed by tensile testing and qualitative histology, respectively. The contralateral intact ATC complex was used as the control.

RESULTS

Failure load of BT was 33.4% lower than that of TT (P = .0243) at week 12. Ultimate strength of BT was 50.2% and 45.3% lower than that of TT at weeks 12 (P = .0002) and 24 (P = .0001), respectively. Tissue morphological characteristics of the BB and TT groups showed faster remodeling. The BT group showed limited regeneration of fibrocartilage zone and excessive formation of fibrous tissue at the healing interface.

CONCLUSION

BTI repair between homogeneous tissues (BB and TT healing) showed better healing quality with respect to mechanical and histological assessments than did healing between heterogeneous tissues (BT healing).

CLINICAL RELEVANCE

Anatomic reconstruction of ATC complex injury may be a primary concern when selecting the proper surgical approach. However, it is recommended to select fracture fixation (BB) or tendon repair (TT) instead of bone-tendon reattachment (BT) if possible to ensure better outcome at the healing interface.

Tissue engineering of ligaments for reconstructive surgery

PURPOSE

The use of musculoskeletal bioengineering and regenerative medicine applications in orthopaedic surgery has continued to evolve. The aim of this systematic review was to address tissue-engineering strategies for knee ligament reconstruction.

METHODS

A systematic review of PubMed/Medline using the terms "knee AND ligament" AND "tissue engineering" OR "regenerative medicine" was performed. Two authors performed the search, independently assessed the studies for inclusion, and extracted the data for inclusion in the review. Both preclinical and clinical studies were reviewed, and the articles deemed most relevant were included in this article to provide relevant basic science and recent clinical translational knowledge concerning "tissue-engineering" strategies currently used in knee ligament reconstruction.

RESULTS

A total of 224 articles were reviewed in our initial PubMed search. Non-English-language studies were excluded. Clinical and preclinical studies were identified, and those with a focus on knee ligament tissue-engineering strategies including stem cell-based therapies, growth factor administration, hybrid biomaterial, and scaffold development, as well as mechanical stimulation modalities, were reviewed.

CONCLUSIONS

The body of knowledge surrounding tissue-engineering strategies for ligament reconstruction continues to expand. Presently, various tissue-engineering techniques have some potential advantages, including faster recovery, better ligamentization, and possibly, a reduction of recurrence. Preclinical research of these novel therapies continues to provide promising results. There remains a need for well-designed, high-powered comparative clinical studies to serve as a foundation for successful translation into the clinical setting going forward.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.