Post traumatic osteolysis is commonly thought of as occurring in the distal clavicle secondary to trauma but is becoming more prominent in the pubis as the population ages. It most typically occurs, as in this case, in post menopausal women and typically with concommitant sacral insufficiency fractures. The differential diagnosis includes infection or tumor, although as in this case, a fluid collection can be present and not a soft tissue component, mitigating against tumor. Biopsy was performed with cultures obtained, both of which were negative.
Case 12 Diagnosis: Amyloidosis
Amyloidosis can occur as a primary, idiopathic process but is more commonly seen in the setting of renal pathology or multiple myeloma. There are multiple types of amyloid that can be deposited about the musculoskeletal system. Deposition is typically in the periarticular soft tissue, within tendons or ligaments, or within the bones about a joint. Deposition of the ossesous structures is seen as nonspecific radiolucencies which can appear as soft tissue or cyst like lesions on cross sectional imaging. There is classically a relative preservation of the joint space which on occasion may be narrowed from a long standing process or secondary processes such as osteonecrosis with secondary arthrosis.
Case 13 Diagnosis: CRMO
Chronic recurrent multifocal osteomyelitis (CRMO) is a poorly understood inflammatory process that overlaps with other inflammatory processes such as SAPHO and the seronegative arthropathies. SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) is more typical of adults while CRMO predominates in children. The delineation between these syndromes is not clear at the present time. CRMO is intermittent with exacerbations and typically has a good prognosis although medical management is somewhat limited at the present.
Case 14 Diagnosis: Myositis Ossificans
Case 15 Diagnosis: Ankylosing Spondylitis with insufficiency fracture
Ankylosing spondylitis has been previously described in an aforementioned case and again represents one of the seronegative arthropathies which causes prominent bone production within the axial skeleton or at the entheses. Although prominent bone is present, it is more predisposed to fracture secondary to rigidity, and fractures often will occur with minor trauma. Pseudarthrosis in ankylosing spondylitis is another common complication thought to represent sequelae of localized inflammatory process centered at the disc space or of previously undiagnosed minor trauma.
Case 16 Diagnosis: Stump Neuroma
Stump neuroma represents a disorganized proliferation of nerve fascicles and fibrosis at the site of a transected nerve in the setting of amputation. Stump neuromas are thought to play a part not only in the localized phenomenon of stump pain but in a more globalized phantom pain of the amputated extremity. The role of peripheral vs. central neurologic factors in the etiology of these phenomena is still to be explained. Recent therapies have utilized neurosclerosing agents such as phenol with limited success.
Case 17 Diagnosis: Aneurysmal Bone Cyst
Aneurysmal Bone Cyst, or ABC, is described histologically as an intraosseous vascular malformation with blood filled spaces. This accounts for the multiple fluid fluid levels seen on cross sectional imaging. Approximately 1/3 of ABC’s occur in the setting of another primary tumor with secondary ABC formation. Periosteal reaction does not occur typically unless there is associated trauma. Lesions are classically expansile, eccentric, and metaphyseal. Diaphyseal and epiphyseal extension does occur.
Case 18 Diagnosis: Tarsal Coalition
Tarsal coalition is an abnormal fusion of the tarsal bones. The fusion is either osseous or non-osseous (fibrous/cartilaginous). Coalitions can be congenital, related to trauma, or secondary to multiple other conditions. Tarsal coalition is one cause of a congenital rigid flatfoot with congenital vertical talus being the other. On imaging, there is bony or fibrocartilaginous tissue fusing the bones with irregular surfaces at the site of the fusion. Edema is elicited secondary to abnormal mechanics and can generate pain. Tarsal coalitions are bilateral 50-60% of the time.
Case 19 Diagnosis: Bucket Handle Tear
Bucket handle tear of the medial meniscus in the setting of a chronic disruption of the ACL. Additional anatomic variant of an oblique meniscomeniscal ligament that extends from the posterior horn of the lateral meniscus to the anterior horn of the medial meniscus. The bucket handle tear is a longitudinal tear with displacement of the meniscal fragment within the intercondylar notch. In a small percentage of people, 1 to 4 %, apart from the transverse meniscal ligament, meniscofemoral ligaments, and meniscotibial ligament, an oblique meniscomeniscal ligament can occur. This courses from the posterior horn of one meniscus to the anterior horn of the other. This can be confused with a bucket handle tear and is crucial to be identified prior to surgery to prevent inappropriate resection.
Case 20 Diagnosis: Juvenile Chronic Arthritis (JCA)
JCA is a heterogeneous collection of inflammatory arthropathies occurring in patients less than 16 years of age. It is typically divided into juvenile onset ankylosing spondylitis, juvenile onset psoriasis/inflammatory bowel disease, juvenile onset adult type RA, and Still’s disease. Still’s disease is then separated into pauciarticular, polyarticular, or systemic variants. Systemic implies serositis, renal disease, hepatosplenomegaly, and lymphadenopathy. The radiologic findings of JCA are similar to adult onset RA except that typically JCA will involve the larger joints first (knees, ankles, and elbow) and the smaller joints of the hand and wrist later. The early findings of JCA are pronounced osteopenia and periarticular soft tissue swelling. With continued hyperemia to the joint there is a ballooning of the ends of the bones, and as the disease progresses, erosions and then ankylosis become present.