Increased perfusion in dynamic gadolinium-enhanced MRI correlates with areas of bone repair and of bone necrosis in patients with Kienböck's disease

Perfusion Imaging of the Musculoskeletal System

Perfusion imaging is the aspect of functional imaging, which is most applicable to the musculoskeletal system. In this review, the anatomy and physiology of bone perfusion is briefly outlined as are the methods of acquiring perfusion data on MR imaging. The current clinical indications of perfusion related to the assessment of soft tissue and bone tumors, synovitis, osteoarthritis, avascular necrosis, Keinbock's disease, diabetic foot, osteochondritis dissecans, and Paget's disease of bone are reviewed. Challenges and opportunities related to perfusion imaging of the musculoskeletal system are also briefly addressed.

Second-look arthroscopic and magnetic resonance analysis after internal fixation of osteochondral lesions of the talus

The purpose of this study was to evaluate cartilage quality after internal fixation of osteochondral lesion of the talus (OLT) using second-look arthroscopies and MRIs. Thirty-four patients underwent internal fixation of OLTs involving large bone fragments. Twenty-one of these patients underwent second-look arthroscopies and 23 patients underwent MRIs postoperatively. The arthroscopic findings were assessed using the International Cartilage Repair Society (ICRS) grading system, and the MRI findings were evaluated using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Five of the patients who underwent second-look arthroscopies showed normal cartilage, 12 showed nearly normal cartilage, 3 showed abnormal cartilage, and 1 showed severely abnormal cartilage, according to the overall ICRS repair grades. All the patients who achieved bone fragment union showed normal, or nearly normal cartilage upon second-look arthroscopy. The ICRS and MOCART scores were significantly higher for the patients with bone fragment union compared to those with nonunion (ICRS scores: 10.3 ± 1.5 vs. 6.0 ± 2.0, p < 0.001, MOCART score: 88.3 ± 10.0 vs. 39.0 ± 20.4, p < 0.001). Low signal intensities of the bone fragments on preoperative T1-weighted MRIs were not associated with nonunion (Fisher's exact test, p = 0.55), and the signal intensities increased postoperatively to levels similar to the underlying talus when bone union was achieved. Second-look arthroscopy and MRI showed normal, or nearly normal, cartilage after internal fixation of OLTs when bone union was achieved. The nonunion of bone fragments resulted in inferior cartilage quality.

Rare earth smart nanomaterials for bone tissue engineering and implantology: Advances, challenges, and prospects

Bone grafts or prosthetic implant designing for clinical application is challenging due to the complexity of integrated physiological processes. The revolutionary advances of nanotechnology in the biomaterial field expedite and endorse the current unresolved complexity in functional bone graft and implant design. Rare earth (RE) materials are emerging biomaterials in tissue engineering due to their unique biocompatibility, fluorescence upconversion, antimicrobial, antioxidants, and anti-inflammatory properties. Researchers have developed various RE smart nano-biomaterials for bone tissue engineering and implantology applications in the past two decades. Furthermore, researchers have explored the molecular mechanisms of RE material-mediated tissue regeneration. Recent advances in biomedical applications of micro or nano-scale RE materials have provided a foundation for developing novel, cost-effective bone tissue engineering strategies. This review attempted to provide an overview of RE nanomaterials' technological innovations in bone tissue engineering and implantology and summarized the osteogenic, angiogenic, immunomodulatory, antioxidant, in vivo bone tissue imaging, and antimicrobial properties of various RE nanomaterials, as well as the molecular mechanisms involved in these biological events. Further, we extend to discuss the challenges and prospects of RE smart nano-biomaterials in the field of bone tissue engineering and implantology.

Perspective on optical imaging for functional assessment in musculoskeletal extremity trauma surgery

SIGNIFICANCE

Extremity injury represents the leading cause of trauma hospitalizations among adults under the age of 65 years, and long-term impairments are often substantial. Restoring function depends, in large part, on bone and soft tissue healing. Thus, decisions around treatment strategy are based on assessment of the healing potential of injured bone and/or soft tissue. However, at the present, this assessment is based on subjective clinical clues and/or cadaveric studies without any objective measure. Optical imaging is an ideal method to solve several of these issues.

AIM

The aim is to highlight the current challenges in assessing bone and tissue perfusion/viability and the potentially high impact applications for optical imaging in orthopaedic surgery.

APPROACH

The prospective will review the current challenges faced by the orthopaedic surgeon and briefly discuss optical imaging tools that have been published. With this in mind, it will suggest key research areas that could be evolved to help make surgical assessments more objective and quantitative.

RESULTS

Orthopaedic surgical procedures should benefit from incorporation of methods to measure functional blood perfusion or tissue metabolism. The types of measurements though can vary in the depth of tissue sampled, with some being quite superficial and others sensing several millimeters into the tissue. Most of these intrasurgical imaging tools represent an ideal way to improve surgical treatment of orthopaedic injuries due to their inherent point-of-care use and their compatibility with real-time management.

CONCLUSION

While there are several optical measurements to directly measure bone function, the choice of tools can determine also the signal strength and depth of sampling. For orthopaedic surgery, real-time data regarding bone and tissue perfusion should lead to more effective patient-specific management of common orthopaedic conditions, requiring deeper penetrance commonly seen with indocyanine green imaging. This will lower morbidity and result in decreased variability associated with how these conditions are managed.