Reconstruction of cranial bone defects using a quick-setting hydroxyapatite cement and absorbable plates.

We examine the 6-month histology of a quick-setting hydroxyapatite cement (Mimix), with and without absorbable plates (LactoSorb), after placement in critical size defects made in the skull of 20 New Zealand white rabbits. Two 10-mm-diameter parietal defects were made in each rabbit. One defect was placed on each side of the sagittal suture. In 10 animals, the left defect was filled with Mimix alone, and in the other 10, an absorbable plate was placed across the base of the left defect before Mimix placement. The right-sided defect served as a control in all animals, with no material placed in or across this defect. The rabbits were killed 6 months postoperatively. A bone pathologist performed histologic examinations of the specimens looking specifically for evidence of inflammatory reaction and bone formation. There was no inflammation around the dura or any other negative histologic reaction in either the study groups or the control. Growth of new bone into the Mimix was found along the periphery in all specimens. We found no migration or displacement of the Mimix from any of the calvarial defects.

Recruitment of osteoclast precursors by stromal cell derived factor-1 (SDF-1) in giant cell tumor of bone.

Giant cell tumor (GCT) of bone is a unique bone lesion that is characterized by an excessive number of multinucleated osteoclasts. GCT consists of neoplastic stromal cells, multinucleated osteoclasts and their precursors, thus serving as a naturally occurring human disease model for the study of osteoclastogenesis. It still remains unclear how stromal cells of GCT recruit osteoclast precursors. In the present study, we characterized the cellular components of GCT and confirmed the presence of CD14(+)-monocytes/CD68(+)-macrophages and CD34(+)-hematopoetic stem cells that express CXCR4, a specific receptor for SDF-1; SDF-1 gene expression and presence of SDF-1 protein were confirmed by real time RT-PCR, in situ hybridization, and immunohistochemistry in the GCT tissue and cultured cells. SDF-1 was present at 25-50 ng/ml in the conditioned media from the GCT cultures, which is in the range of physiological chemotactic concentration. Migration of osteoclast precursors was 2.5-fold higher in response to GCT conditioned media compared to the control media; and migration was inhibited by an average of 36% with anti-SDF-1 neutralizing antibody or competing recombinant SDF-1. These results suggest that SDF-1 is one of the significant chemoattractant factors involved in the recruitment of hematopoietic osteoclast precursor cells during tumor-induced osteoclastogenesis.

Novel translocation (9;12)(q22;q24) in secondary chondrosarcoma arising from hereditary multiple exostosis.

We report a new translocation in a patient with a history of hereditary multiple exostosis (HME) who developed a recurrent grade I chondrosarcoma involving the sacrum and retroperitoneum. Karyotypic analysis of the tumor revealed a sole chromosome abnormality t(9;12)(q22;q24.3). To our knowledge, this translocation has not been previously identified in either chondrosarcoma, HME, or related tumor types. Our novel translocation may be related to the sarcomatous degeneration of the pre-existing exostosis.

The role of flexor tenosynovectomy in the operative treatment of carpal tunnel syndrome.

BACKGROUND: We conducted a prospective, randomized study to evaluate the effect of flexor tenosynovectomy as an adjunct to open carpal tunnel release for the treatment of idiopathic carpal tunnel syndrome and reviewed the histological characteristics of the flexor tenosynovium to identify possible correlations between histopathology and symptoms. METHODS: Eighty-eight wrists in eighty-seven patients with idiopathic carpal tunnel syndrome were randomized to open carpal tunnel release with or without flexor tenosynovectomy. A validated self-administered questionnaire for the assessment of symptom severity and functional status was completed both before and after the operation to assess patient outcome. The study group included fifteen men and seventy-two women with a mean age of fifty-eight years. All patients were followed for a minimum of twelve months after the operation. Intraoperatively, the tenosynovium of all patients was graded on the basis of its gross appearance. Half of the wrists were then treated with a flexor tenosynovectomy through the operative incision, and the tenosynovium was graded histologically. Correlations were sought between the gross appearance of the tenosynovium and the preoperative and postoperative symptoms and functional status, between the histologic appearance of the tenosynovium and the preoperative and postoperative symptoms and functional status, and between the gross and the histologic findings. RESULTS: After the operation, both groups improved significantly with respect to symptom severity and functional status (paired t test), with no significant difference between the groups (unpaired t test). No significant correlation was found between the gross appearance of the tenosynovium and the preoperative or postoperative symptoms and functional status, between the histologic appearance of the tenosynovium and the preoperative or postoperative symptoms and functional status, or between the gross and the histologic findings. CONCLUSIONS: We observed neither an added benefit nor an increased rate of morbidity in association with the performance of a flexor tenosynovectomy at the time of carpal tunnel release. We identified no clinical correlations that might predict which individuals would benefit from flexor tenosynovectomy on the basis of either the gross (intraoperative) or histologic evaluation of the flexor tenosynovium. Our findings suggest that routine flexor tenosynovectomy offers no benefit compared with sectioning of the transverse carpal ligament alone for the treatment of idiopathic carpal tunnel syndrome.

Diagnostic value and limitations of fluorine-18 fluorodeoxyglucose positron emission tomography for cartilaginous tumors of bone.

BACKGROUND: A variety of imaging modalities are currently used for the preoperative evaluation of cartilage tumors. Although the anatomic details of the lesions are demonstrated well on computerized tomography and magnetic resonance images, those studies yield little information about the biologic activity of the tumors. In this study, we investigated the glucose metabolism of cartilage tumors measured by positron emission tomography and its correlation with histopathologic grades. METHODS: Thirty-five biopsy-proven cartilaginous tumors in twenty-seven patients were studied with plain radiographs, bone-scanning, magnetic resonance imaging, and positron emission tomography. The glucose metabolism in these cartilaginous tumors was measured quantitatively by calculating the maximal standardized uptake value of the region of interest. This value was then correlated with histopathologic grade, tumor size, recurrence, and metastasis. RESULTS: There were thirteen benign bone tumors, twelve grade-I chondrosarcomas, and ten high-grade (grade-II or III) chondrosarcomas. The mean maximal standard uptake values were 1.147 +/- 0.751 in the benign tumors, 0.898 +/- 0.908 in the grade-I chondrosarcomas, and 6.903 +/- 5.581 in the high-grade chondrosarcomas. There was no significant difference in these values between the benign cartilage tumors and the grade-I chondrosarcomas (p > 0.05). However, there was a significant difference between the low-grade (benign and grade-I) and high-grade chondrosarcomas (p = 0.009). Metastasis, but not tumor size or recurrence, was associated with a higher standard uptake value (p = 0.031). Two large pelvic grade-I chondrosarcomas demonstrated no radioisotope uptake on bone-scanning or on positron emission tomography. Positron emission tomography demonstrated grade-II and III metastatic lesions in the lung and other anatomic locations. When the cutoff for the standardized uptake value was set at 2.3 for grade-II or III chondrosarcomas, the positive predictive value was 0.82 (95% confidence interval, 0.48 to 0.97) and the negative predictive value was 0.96 (95% confidence interval, 0.77 to 1.00). CONCLUSIONS: Grade-II and III chondrosarcomas have a higher glucose metabolism than do low-grade cartilage tumors. However, the measurement of glucose metabolism by positron emission tomography alone cannot distinguish between benign and grade-I malignant cartilaginous tumors. It is important to understand the advantages and disadvantages of imaging modalities for accurate interpretation of results. Although positron emission tomography has limitations, it may be useful for predicting high-grade chondrosarcomas. LEVEL OF EVIDENCE: Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference "gold" standard]). See Instructions to Authors for a complete description of levels of evidence.

Mucormycosis of the upper extremity in a patient with alcoholic encephalopathy.

UNLABELLED: Cutaneous mucormycosis is a rare opportunistic infection caused by fungi of the class Zygomycetes that can be rapidly fatal if unrecognized. The diagnosis of this infection is often made by infectious disease, dermatologic, or intensive care specialists. Lesions that affect the upper limb may require a hand surgeon to diagnose the infection. The diagnosis may be difficult to make, because these infectious lesions can be confused with ischemic pathology. We report on a rare case of cutaneous mucormycosis caused by Rhizopus arrhizus in a patient with cirrhosis and renal failure who presented with an ischemic hand. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic V.

18FDG-PET applications for cartilage neoplasms.

OBJECTIVE: To assess the value of [18F]fluoro-2-deoxy-D-glucose positron emission tomography (18FDG-PET) in defining aggressive cartilage neoplasms, particularly those with problematic or borderline histologic, imaging and clinical characteristics. DESIGN AND PATIENTS: From 2000 to 2003, 29 cartilage lesions were studied with whole-body 18FDG-PET scans (Siemens Ecat Exact, Knoxville, Tenn.). Analyses of data in 20 females and nine males, 11-85 years old, were based on maximum standard uptake values (SUVs) in regions of interest (ROIs) on axial 3.37 mm thick, 3x3 pixel images. A statistically significant maximum SUV cutoff of 2.0 was used to distinguish benign from malignant cartilage neoplasms and correlated with the postoperative histopathologic findings. RESULTS: In 26 operated cases the overall sensitivity of whole-body 18FDG-PET in separating benign and malignant lesions was 90.9% (10/11), specificity 100% (18/18) and accuracy 96.6%. CONCLUSIONS: Whole-body 18FDG-PET is a valuable adjunct in identifying primary, recurrent and metastatic cartilage malignancies. It supplements classic histology and morphologic imaging with functional data which may facilitate management in individual cases.

Extranodal Rosai-Dorfman disease of bone, subcutaneous tissue and paranasal sinus mucosa with a review of its pathogenesis.

We report an unusual case of extranodal Rosai-Dorfman disease presenting in a 36-year-old man with lesions of bone, subcutaneous tissue of the arm and maxillary sinus mucosa unassociated with lymphadenopathy or systemic symptoms. These lesions appeared metachronously within a 6-month period. The diagnostic light microscopic and immunohistochemical findings and pathogenesis of this interesting disease are discussed.

Osseous sarcoidosis of the hand: pathologic analysis and review of the literature.

A destructive granulomatous process involving the right fifth metacarpal and the soft tissues of the right thumb and nose of an African-American woman without pulmonary disease is described. The initial biopsy examination of the metacarpal showed caseating and noncaseating granulomata. After a fifth-ray amputation the disease progressed, leading to the referral of the patient to our institution. A biopsy examination of this recurrence showed a predominance of solid noncaseating granulomata. The diagnosis of sarcoidosis was made on the basis of the morphology of the granulomata and by exclusion of infectious and neoplastic causes. Steroid therapy has resulted in cessation of clinical and radiographic disease progression at a 3-year clinical follow-up evaluation.

The effects of implant composition on extensor tenosynovitis in a canine distal radius fracture model.

PURPOSE: Dorsal plating of distal radius fractures with titanium plates has resulted in clinically observed tenosynovitis and tendon rupture. The goal of this study was to investigate whether titanium-based implants result in more extensor tendon inflammation than matched stainless-steel implants in a canine fracture model. METHODS: An osteotomy was created in the distal radius of 18 beagles and fixed with 2.7-mm 4-hole plates composed of commercially pure titanium, titanium alloy (Ti-Al6-V4), or 316L stainless steel. Animals were killed at an average of 4 months. Tendon gliding was assessed by applying a force at the extensor musculotendinous junction and noting gliding. Histologic grading (mild, moderate, severe) was based on cellular hypertrophy, hyperplasia, and leukocytic infiltration. RESULTS: Tendons glided freely in 100% stainless-steel specimens, 75% of titanium alloy, and 43% of commercially pure titanium groups. A severe inflammatory reaction was identified in 60% of the titanium alloy (Ti-A16-V4) group, 57% of the pure titanium group, and 0% of the stainless-steel group. CONCLUSIONS: Dorsal plating of the canine radius with commercially pure titanium or titanium alloy implants produced a greater inflammatory peritendinous response than matched stainless-steel implants.

Magnetic resonance imaging depiction of tight iliotibial band in melorheostosis associated with severe external rotation deformity, limb shortening and patellar dislocation in planning surgical correction.

We present the case of a 14-year-old male with melorhesotosis and severe iliotibial band tightness which was associated with femoral shortening, severe external rotational deformity of the femur, genu valgum and patellar dislocation in the right lower extremity. Skeletal survey revealed irregular radiodense streaks involving the pelvis, femoral head, femoral shaft, distal femoral epiphysis, talus and middle phalangeal bones of the foot. Magnetic resonance (MR) imaging showed thickening of the iliotibial band in addition to low MR signal changes in the bone. Intraoperatively fibrosis in the subcutaneous layer and a thickened iliotibial band were found. MR images were very useful in understanding the soft tissue pathoanatomy in melorheostosis and planning surgical correction.