Imaging of the patellofemoral joint.

The patellofemoral (PF) joint is a complex articulation, with interplay between the osseous and soft tissue structures to maintain the balance between knee mobility and stability. Disorders of the PF joint can be a source of anterior knee pain (AKP). In this article, radiographic and magnetic resonance imaging of the PF joint are reviewed, including normal anatomy, imaging techniques, and imaging-based measurements. Common imaging findings associated with AKP are reviewed, including symptomatic normal variants, tendinopathy, apophysitis, osteoarthritis, chondromalacia patella, trochlear dysplasia, excessive lateralization of tibial tuberosity, patellar maltracking, patellar dislocation and fractures, anterior bursitis, Morel-Lavallée effusions, and fat pad edema.

Os cuboideum secundarium: a rare accessory ossicle with the potential to mimic a mass on magnetic resonance imaging.

Accessory ossicles are common incidental findings on radiographs of the ankle and foot. While typically asymptomatic and of no clinical significance, they are sometimes associated with local pain or even mistaken for pathological conditions such as fractures. Given the potential for misinterpretation, it is important to understand their typical locations and appearances. This case highlights an exceptionally rare accessory ossicle called the os cuboideum secundarium, located adjacent to the cuboid and calcaneus. Interestingly, this case demonstrates the potential for this rare ossicle to mimic a mass on magnetic resonance imaging (MRI). Furthermore, despite the significant improvements in the understanding of musculoskeletal pathology afforded by advancements in cross-sectional imaging techniques, this case is a reminder of certain pitfalls that remain. Lastly, it highlights the importance of radiographs as an initial diagnostic study in evaluating foot pain.

The clinical evaluation of bone tumors.

Bone tumors are uncommon clinical entities that are often a source of diagnostic and therapeutic uncertainty. Evaluating these lesions starts with a patient history and physical examination Imaging then begins with radiographs, followed by advanced imaging modalities, such as magnetic resonance imaging, computed tomography, or bone scan. Biopsy can be performed to establish histologic diagnosis by either closed or open means. Treatment options range from observation to wide resection with reconstruction or amputation. Surveillance schedules vary depending on the type of tumor that is being treated. An algorithm for the evaluation, work-up, and diagnosis of bone tumors is presented.

The clinical evaluation of soft tissue tumors.

Soft tissue tumors range from benign subcutaneous lipomas to malignant deep high-grade sarcomas. Patients are evaluated with a thorough history and physical examination followed by imaging studies. Magnetic resonance imaging is the modality of choice, although radiographs, computed tomography, and other modalities may be of value. Open or closed biopsy can be performed to establish a diagnosis. Treatment depends on the diagnosis and includes observation or marginal excision for benign lesions and wide resection for malignant masses, with radiation therapy or chemotherapy for large, high-grade tumors. An algorithm for the evaluation, diagnosis, and treatment of soft tissue tumors is presented.

Mimics of bone and soft tissue neoplasms.

Many benign nonneoplastic entities can mimic bone and soft tissue tumors on imaging examinations. Distinguishing between neoplastic and nonneoplastic entities depends on history and physical examination findings and imaging findings, and is an important early step in the patient's overall workup and treatment plan. This article describes some of the pseudotumors seen on imaging studies in our orthopedic oncology clinic, as well as mimics of bone and soft tissue neoplasms described in the medical literature. Tumor mimics resulting from anatomic and developmental variants, trauma, infection and inflammation, osteonecrosis and myonecrosis, articular and juxta-articular conditions, and miscellaneous causes are discussed.

The incidence and prognosis of osteosarcoma skip metastases.

The poor prognosis for patients with osteosarcoma skip metastases has been established in the literature; however, most of the data in the literature concerning osteosarcoma skip metastases were collected before routine use of magnetic resonance imaging and before the use of modern multiagent chemotherapy regimens. This retrospective multiinstitutional study was done to evaluate the efficacy of magnetic resonance imaging to detect skip metastases and to evaluate the prognosis for these patients when treated with modern multiagent chemotherapy protocols. In a group of 155 patients who were younger than 26 years when diagnosed and treated for high-grade osteosarcoma of the long bones, 10 (6.5%) patients with skip metastases were identified. Eight of the 10 lesions were detected on pretreatment magnetic resonance imaging scans and two were detected only from the surgical pathology specimens. Five patients had concomitant pulmonary metastases at presentation and five patients had no other known site of diseases. All 10 patients died, with an average survival of 32.5 months (range 11-71 months). The five patients with only skip metastases at presentation survived an average of 27.2 months (range 15-44 months). Despite advances in the treatment of patients with osteosarcomas, those with skip metastases continue to have a poor prognosis, and they should be counseled regarding the limitations of current therapies.

A comparison study of staging systems for bone sarcomas.

A retrospective study of 250 patients treated at one institution was done to evaluate the prognostic significance of the new American Joint Committee on Cancer staging system compared with the Musculoskeletal Tumor Society staging system for patients with sarcomas of bone. Regarding the Musculoskeletal Tumor Society system, there were significant differences in survival among patients with Stage I, Stage II, and Stage III disease. There were no significant differences between patients with Stages I-A and I-B disease, nor between patients with Stages II-A and II-B disease. Similarly, regarding the new American Joint Committee on Cancer staging system, there were significant differences among patients with Stage I, Stage II, and Stage IV disease. No significant differences were seen between patients with Stages I-A and I-B disease, between patients with Stages II-A and II-B disease, nor between patients with Stages IV-A and IV-B disease. A significant advantage in the ability to predict prognosis for one staging system over the other staging system was not shown with the relatively small number of patients in this study.