Mark D. Murphey

Distal Chevron Osteotomy with Lateral Release for Treatment of Hallux Valgus Deformity

From 1986 to 1990, 42 feet in 30 patients had a combined chevron osteotomy and lateral release to correct their painful bunion deformity. Seventeen patients, 23 feet, were available for follow-up. The purpose of this study was to evaluate the outcome of this procedure and to determine the incidence of avascular necrosis. The patients were examined by an independent examiner, radiographs obtained, and questionnaires filled out. Avascular necrosis was determined using plain films read by a musculoskeletal radiologist who did not know the outcomes. The average age was 45 years at the time of the procedure. Average follow-up was 50 months. The preoperative intermetatarsal angle averaged 13° and the hallux valgus angle averaged 31°. At study follow-up, the intermetatarsal angle averaged 8° and the hallux valgus angle averaged 17.5°. The results were graded by the Mayo Clinic Forefoot Scoring System (75-point scale) and a subjective scoring system. Average postoperative Mayo Clinic score was 67. Fifteen feet were subjectively rated as excellent, six as good, and two as fair. Complications occurred in four feet. Hallux varus occurred in two feet, extension contracture in one foot, and an infection in one foot. None of the feet developed definite radiographic evidence of avascular necrosis. Distal chevron osteotomy combined with a lateral release for corrective bunion surgery has come under scrutiny, because of the risk of avascular necrosis of the first metatarsal head. However, our study showed no evidence of avascular necrosis on radiographs. In addition, 91% of patients had good to excellent results at an average 50-month follow-up.

Improved differentiation of benign osteochondromas from secondary chondrosarcomas with standardized measurement of cartilage cap at CT and MR imaging

PURPOSE To validate a technique for reproducible measurement of the osteochondroma cartilage cap with computed tomography (CT) and magnetic resonance (MR) imaging and to reevaluate the correlation of the thickness of the cartilage cap with pathologic findings to improve noninvasive differentiation of benign osteochondromas from secondary chondrosarcomas. MATERIALS AND METHODS The institutional review board approved the study and waived the need for informed consent. HIPAA compliance was maintained. After validation of the measurement technique, 101 pathologically confirmed osteochondromas were retrospectively reviewed. Patient demographic data, histologic diagnosis, and chondrosarcoma grade were recorded. Two musculoskeletal radiologists used a standardized technique to independently measure the thicknesses of the cartilage caps on CT and MR images; these measurements were compared for interobserver agreement. Agreement between measurements with CT and MR imaging was also evaluated, as were the sensitivity and specificity of both modalities for differentiation of osteochondromas from chondrosarcomas. RESULTS Evaluated were 67 benign osteochondromas (from 49 male patients and 18 female patients; mean age, 23.4 years) and 34 secondary chondrosarcomas (from 27 male patients and seven female patients; mean age, 33.2 years). On the basis of the proposed measuring technique, there was 88% interobserver measurement agreement with MR imaging (95% confidence interval [CI]: 80%, 94%) and 93% with CT (95% CI: 84%, 98%). The median difference between measurements of cap thickness at CT and MR imaging was 0 cm (25th and 75th percentiles, -3 mm and 1 mm, respectively). With 2 cm used as a cutoff for distinguishing benign osteochondromas from chondrosarcomas, the sensitivities and specificities were 100% and 98% for MR imaging and 100% and 95% for CT, respectively. CONCLUSION The proposed measuring technique allows accurate and reproducible measurement of cartilage cap thickness with both CT and MR imaging. Cap thickness of 2 cm or greater strongly indicated secondary chondrosarcomas.

Langerhans' cell histiocytosis in patients older than 21 years.

In this retrospective review of 541 patients with Langerhans’ cell histiocytosis, 211 (39%) patients were older than 21 years of age, whereas 330 (61%) were younger than 21 years of age. The adult patients had a mean age of 32 years (range, 21–69 years) with 159 (75%) men and 52 (25%) women, whereas the pediatric patients consisted of 176 (55%) boys and 144 (45%) girls. This male predominance in adults was statistically significant. Three adults had the Hand-Schuller-Christian variant, whereas the remaining adults (208) had eosinophilic granuloma. The rib accounted for 25% of the adult lesions and only 8% of the pediatric lesions. Spine involvement was less common in the adult group (3% versus 10%) and was predominantly thoracic. The adult patients had 40 (77%) diaphyseal lesions, 12 (23%) metaphyseal lesions, and no epiphyseal lesions. The pediatric patients had 75 (54%) diaphyseal, 59 (42%) metaphyseal, and five (4%) epiphyseal lesions. Radiographic evaluation revealed similar margin and matrix patterns in both groups, with a geographic lesion without sclerotic borders being the most common pattern. Langerhans’ cell histiocytosis is considered a pediatric disease. However, this study showed a significant number (39%) of patients older than 21 years of age with this condition.

Gout in the axial skeleton.

Objective. Gout typically affects the peripheral joints of the appendicular skeleton and rarely involves the axial joints. The literature on axial gout is limited to case reports and case series. This preliminary study was conducted to identify the frequency and characteristics of axial gout. Methods. Six hundred thirty medical records with ICD codes 274.0, 274.82, and 274.9 for peripheral gout were reviewed. Ninety-two patients had clinical or crystal-proven gout, of which 64 had prior computed tomography (CT) images of the spine performed for various medical reasons. These CT images were reviewed for features of axial gout, which include vertebral erosions mainly at the discovertebral junction and the facet joints, deposits of tophi, and erosions in the vertebral body, epidural space, ligamentum flavum and pars interarticularis. Results. Nine of the 64 patients had radiographic changes suggestive of axial gout. Lumbar vertebrae were most commonly involved, with facet joint erosions being the most common finding. Isolated involvement of the sacroiliac joints was seen in 2 patients. Axial gout had been diagnosed clinically in only one patient. Conclusion. Radiologic changes of axial gout were more common than recognized clinically, with a frequency of 14%. Since not all patients had CT images, it is possible that the frequency of axial involvement was even greater. A prospective study is needed to further define this process.

World Health Organization classification of bone and soft tissue tumors: modifications and implications for radiologists.

The working group of the World Health Organization (WHO) for classification of tumors of soft tissue and bone met in 2002. The consensus of this conference led to modifications in the nomenclature primarily for soft tissue neoplasm, leaving osseous tumors largely unaltered. The most significant changes in nomenclature involved the group of fibrous and lipomatous malignancies. This article reviews the modifications of this nomenclature and the justification for these changes. The WHO suggested replacement of the term MALIGNANT FIBROUS HISTIOCYTOMA (MFH) with undifferentiated high-grade pleomorphic sarcoma and combining myxoid and round cell liposarcoma under the umbrella of myxoid liposarcoma. The imaging appearances of the fibrous and lipomatous malignancies is reviewed and emphasized in this article. It is important for radiologists involved in evaluation of these lesions to have an understanding of the current nomenclature. This allows improved uniformity in our discussions with pathologists and orthopedic oncologists in our team approach in the diagnosis and treatment of these patients.

Chondroblastoma of the Foot

A total of 322 cases of chondroblastoma were referred to the Armed Forces Institute of Pathology between 1960 and 1990. Ten additional cases of chondroblastoma were treated at Walter Reed Army Medical Center between 1985 and 1993. Forty-two of these involved the foot, two of which were treated at Walter Reed Army Medical Center. Patients with chondroblastoma of the foot were male in 35 (81%) cases, with a mean age of 25.5 years, which was significantly different from the mean age of 17.3 years in patients with chondroblastoma of the long bones (P < 0.0001). Chondroblastoma of the foot is most commonly found in the posterior subchondral areas of the talus and calcaneus as well as in the calcaneal apophysis. Radiographically, the lesion was associated with an articular surface or apophyseal area in all cases and appeared radiolucent, with little to no matrix production. The margins were generally well defined. Cystic features were noted grossly and histologically in 24 (57%) specimens, a feature seen in only 21% of all chondroblastomas overall. Treatment consists of thorough curetting and bone grafting with good oncologic and functional results.

Tenosynovial (extraarticular) chondromatosis: An analysis of 37 cases of an underrecognized clinicopathologic entity with a strong predilection for the hands and feet and a high local recurrence rate

Tenosynovial chondromatosis is a multinodular cartilaginous proliferation that arises from the tenosynovial membranes. This report describes the clinical, radiologic, and histopathologic findings in 37 cases of this uncommon entity. There were 17 males and 20 females, ranging in age from 20 to 86 years (mean and median age, 46 years). The process involved tenosynovium of the fingers (n = 19), feet (n = 8), wrists (n = 4), ankles (n = 2), hand, not otherwise specified, or palm (n = 2), knee (n = 1), and forearm (n = 1). Signs of disease or symptoms were present for 5 weeks to 18 years (median duration, approximately 2 years) before surgical excision. The two most common complaints were a painless mass and a mass that was mildly tender with pressure. None of the tumors had clinical, radiologic, or histopathologic evidence of articular or bone involvement. Histologically, all tumors consisted of a multinodular cartilaginous proliferation involving tenosynovium and/or subsynovial connective tissue. Mild or moderate atypia, as encountered in chondroma of soft parts and synovial chondromatosis, was a frequent finding. Follow-up information was available for 16 patients (43%). Only two patients with follow-up information remained disease free after their initial surgical procedure. Seven patients had one recurrence and seven patients had two or more recurrences. Tenosynovial chondromatosis appears to be an extraarticular counterpart of synovial (intraarticular) chondromatosis. Our review indicates this process is often confused with chondroma of soft parts, in part, because both entities have a predilection for the hands and feet. Diagnosis of this underrecognized entity is of clinical importance because of the high local recurrence rate.

Magnetic Resonance Imaging of Benign Soft Tissue Neoplasms in Adults

This article reviews a spectrum of benign soft tissue tumors found in adults. Rather than presenting a complete review, the focus of this article is on benign tumors for which the diagnosis may be confidently made or strongly suggested on the basis of imaging. Diagnoses presented include nodular fasciitis, superficial and deep fibromatosis, elastofibroma, lipomatous lesions, giant cell tumor of the tendon sheath, pigmented villonodular synovitis, peripheral nerve sheath tumors, Morton neuroma, hemangioma, and myxoma.

From the Radiologic Pathology Archives: Ewing Sarcoma Family of Tumors: Radiologic-Pathologic Correlation

The Ewing sarcoma family of tumors includes osseous Ewing sarcoma, extraskeletal Ewing sarcoma, primitive neuroectodermal tumor, and Askin tumor. They share a karyotype abnormality with translocation involving chromosomes 11 and 22. Histologically, these lesions demonstrate crowded sheets of small round blue cells. Imaging features of osseous Ewing sarcoma often suggest the diagnosis, with aggressive long-bone destruction in the metadiaphysis of an adolescent or young adult and an associated soft-tissue mass. Focal areas of cortical destruction are frequent, allowing continuity between the intraosseous and extraosseous components. This continuity is also commonly seen as subtle channels extending through the cortex at computed tomography or magnetic resonance (MR) imaging, a finding that reflects the underlying pathologic appearance. Extraskeletal Ewing sarcoma commonly demonstrates a nonspecific radiologic appearance of a large soft-tissue mass affecting the paraspinal region or lower extremity. Askin tumor represents extraskeletal Ewing sarcoma involving the chest wall. Imaging typically reveals a large pleural-based mass and associated pleural effusion. Treatment of these tumors is usually a combination of neoadjuvant chemotherapy followed by surgical resection, which may be supplemented with radiation therapy. Imaging, particularly MR, is also vital to evaluate response to neoadjuvant therapy, direct surgical resection, and detect local recurrence or metastatic disease.

Incidental Enchondromas of the Knee

OBJECTIVE The purpose of our study was to determine the prevalence of incidental enchondromas on routine MR knee imaging. MATERIALS AND METHODS We retrospectively reviewed 449 consecutive routine knee MR examinations for the presence of enchondromas. MRI was considered positive when a focal geographic area of lobular marrow replacement (nonsubchondral) was identified on T1 weighting and high signal intensity was seen on T2 weighting. Patients with enchondromas were further evaluated for demographics; lesion site, size, and relationship to the physeal plate; aggressive imaging features described with chondrosarcoma; concurrent internal derangement; and study indication. RESULTS The prevalence of incidental enchondromas was 2.9% on routine knee MR examinations. The prevalence was highest in the distal femur (2.0%), followed by the proximal tibia (0.7%) and the proximal fibula (0.2%). The average lesion size was 1.9 x 1.2 x 1.3 cm (57% of lesions were < 1 cm). Most lesions were located in the metaphysis (71%) or diaphysis (21%). Enchondromas were within 1.5 cm of the physeal plate in 72% of cases. No aggressive imaging features to suggest chondrosarcoma were seen. All patients had evidence of internal derangement as the cause of symptoms and the request for imaging. CONCLUSION Incidental enchondromas can be identified on 2.9% of routine MR knee examinations, most frequently in the distal femur (2.0%). This significant prevalence is much higher than in an autopsy series (0.2%), likely reflecting the increased sensitivity of MRI for detecting small lesions, and is important to recognize to avoid confusion with other pathologic entities.