Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.

Background: Evaluations of the stability of osteochondritis dissecans (OCD) lesions of the elbow using magnetic resonance imaging (MRI) have resulted in reports with variable accuracy. Therefore, the International Cartilage Repair Society (ICRS) classification remains the gold standard to determine OCD lesion stability. Because OCD commonly occurs in pediatric patients, a noninvasive method comparable with the ICRS classification is desired. Hypothesis/Purpose: Based on the previous literature, the capitellum of unstable OCD lesions has an irregular outline on MRI because of displacement or dislocation of the lesion via synovial fluid inflow. Therefore, we defined a 4-stage classification, similar to the ICRS classification, which focused on the outline of the capitellum and articular cartilage status on MRI without subchondral bone information. The purpose of this study was to validate this MRI-based staging system against the ICRS classification and to verify its accuracy in diagnosing unstable OCD lesions of the elbow. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 81 patients with OCD of the elbow who were surgically treated were evaluated. The MRI-based stages were as follows: stage 1, normal-shaped capitellum and articular cartilage without signal intensity change; stage 2, normal-shaped capitellum and articular cartilage with signal intensity change; stage 3, irregular-shaped capitellum and discontinuity of the articular cartilage; and stage 4, dislocated lesion with an articular cartilage defect. Agreement between the MRI and ICRS classifications was evaluated, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for lesion instability were determined. The intraclass correlation coefficient (ICC) for intrarater and interrater reliability of the MRI-based staging system was calculated. Results: Agreement between the MRI-based staging system and the ICRS classification was 88.9%, with a sensitivity of 98.4%, specificity of 84.2%, PPV of 95.3%, and NPV of 94.1% for diagnosing an unstable lesion. The ICC was high for both intrarater (0.925) and interrater (0.915-0.939) reliability. Conclusion: The MRI-based staging system corresponded well with the ICRS classification, providing an accurate preoperative assessment of OCD lesions of the elbow, even with minimal subchondral bone information.

The carpal scaphoid is the most commonly fractured carpal bone in young adults after a fall on an outstretched arm that results in acute dorsal flexion of the wrist. However, stress fractures of the scaphoid are relatively rare. To the best of our knowledge, we describe the first case in the literature of carpal scaphoid stress fracture in a tennis player. An 18-year-old Japanese man who was an elite junior tennis player was referred to our hospital after radiography and computed tomography revealed a carpal scaphoid fracture. The patient presented with pain in the wrist joint and tenderness over the anatomical snuff-box with diffuse swelling and reduced active dorsal flexion and flexion of the right wrist. The patient was treated conservatively and resumed participation in competitive events 5 months after his initial presentation. In this case, the scaphoid stress fracture had resulted from repetitive practicing of the attacking backhand high volley, which involved excessive dorsal flexion of the wrist. Although rare, scaphoid stress fractures must be considered in tennis players with chronic wrist pain.

We report the case of a patient who noticed muscle weakness in his left arm 5 years earlier. On examination, a biloculate mass was observed in the left supraclavicular area, and Tinel's sign caused paresthesia in his left arm. Magnetic resonance imaging showed a continuous, multinodular, plexiform tumor from the left C5 to C7 nerve root along the course of the brachial plexus to the left brachia. Tumor excision was attempted. The median and musculocutaneous nerves were extremely enlarged by the tumor, which was approximately 40 cm in length, and showed no response to electric stimulation. We resected a part of the musculocutaneous nerve for biopsy and performed latissimus dorsi muscle transposition in order to repair elbow flexion. Morphologically, the tumor consisted of typical Antoni A areas, and immunohistochemistry revealed a Schwann cell origin of the tumor cells moreover, there was no sign of axon differentiation in the tumor. Therefore, the final diagnosis of plexiform Schwannoma was confirmed.

The digital nerves are important for normal hand function. In addition to conventional therapies such as neurolysis, direct repair, and auto/allografts, new treatments administering growth factors and cells for promoting nerve regeneration exist. Platelet‐rich plasma (PRP), an autologous product with proven therapeutic effects for musculoskeletal disorders, is a new treatment option for peripheral nerve injury. We hypothesized that PRP could stimulate healing of digital nerve injuries. In the current case report, intraoperative local administration of PRP was performed during neurolysis surgery for a healthy 28‐year‐old woman with digital nerve crush injury. Five weeks postinjury, surgery was performed due to severe uncontrollable neuropathic pain and no sensory nerve action potential derivation of the index finger. Therapeutic effects were assessed by physical examination, visual analog scale for pain, and nerve conduction study. Postoperatively, early neuropathic pain relief and good functional recovery were obtained with no PRP‐related adverse events. This case report demonstrates the therapeutic potential of intraoperative PRP to enhance the healing process of nerve crush injury in the acute phase and to decrease the neuropathic pain, thus enhancing healing of peripheral nerve crush injury.