Percutaneous pinning of the proximal part of the humerus. An anatomic study.

BACKGROUND: Closed reduction and percutaneous pinning of unstable proximal humeral fractures is a well-described technique with some theoretical advantages over open techniques. To our knowledge, the risk of injury to neurovascular structures from percutaneous pinning of the proximal part of the humerus has not been studied. We sought to quantify this risk using a cadaveric model. METHODS: In ten fresh-frozen cadaveric shoulders, the intact proximal part of the humerus was pinned under fluoroscopic guidance with use of an identical published technique. A total of five 2.5-mm terminally threaded AO pins, including two lateral, one anterior, and two greater tuberosity pins, were used in each shoulder. The specimens were then dissected to determine the distance of each pin from adjacent neurovascular structures as well as key anatomic relationships. RESULTS: The proximal lateral pins were located at a mean distance of 3 mm from the anterior branch of the axillary nerve. Four of the twenty lateral pins were noted to penetrate the articular cartilage of the humeral head. The anterior pins were located at a mean distance of 2 mm from the tendon of the long head of the biceps (perforating the tendon in three specimens) and of 11 mm from the cephalic vein (perforating the vein in one specimen). The proximal tuberosity pins were located at a mean distance of 6 and 7 mm from the axillary nerve and the posterior humeral circumflex artery (tenting the structures in two specimens with internal rotation), respectively. These pins moved away from the nerve with external rotation of the humerus. CONCLUSIONS: The technique used in this study may be associated with a risk of injury to important anatomic structures about the shoulder. Lateral pins should be distal enough to avoid injury to the anterior branch of the axillary nerve, and multiple fluoroscopic views should be obtained to avoid penetration of the humeral head cartilage. There may be a risk of injury to the cephalic vein, the biceps tendon, and the musculocutaneous nerve with use of anterior pins, and these pins should be employed with caution. Greater tuberosity pins should be placed with the arm in external rotation, should be aimed for a point 20 mm from the inferior aspect of the humeral head, and should not overpenetrate the cortex.

Extraskeletal myxoid chondrosarcoma.

The medical records and histologic material of 16 patients with extraskeletal myxoid chondrosarcoma were reviewed. The mean age of the patients was 52 years. Thirteen tumors arose in the lower extremity. Thirteen patients presented with primary, localized disease, whereas three presented with pulmonary metastases. Treatment of the primary site included wide excision or amputation in 13 patients and marginal or intralesional resections with radiation in three patients. The mean followup was 7.4 years. Five patients were continuously disease free (5- and 10-year event free survival 43% and 14%, respectively). Local recurrence developed in four, and metastases developed in six of 13 patients presenting with localized disease. Of six patients who received chemotherapy for systemic disease, four had disease progression and died, and two had a response to chemotherapy (one partial, one complete). The mean survival after onset of metastases was 45 months. Overall 5- and 10-year survival was 87% and 63%, respectively. The current series suggests that extraskeletal myxoid chondrosarcoma is an intermediate-grade neoplasm with a tendency toward recurrence and metastasis. Survival after relapse may be prolonged. More effective therapy for systemic disease is needed.

Synovial chondromatosis of the shoulder.

We describe a case of synovial chondromatosis involving the shoulder. Presenting symptoms, radiographic features, intraoperative findings, and treatment options are discussed.

Extraskeletal myxoid chondrosarcoma: a clinicopathologic, immunohistochemical, and ploidy analysis of 23 cases.

Twenty-three cases of extraskeletal myxoid chondrosarcoma, evaluated at the Mayo Clinic between 1968 and 1996, were studied for clinicopathologic features, immunohistochemical profile, Ki-67 activity, and ploidy status to identify adverse prognostic factors. Females and males were equally affected, and the median age at diagnosis was 50 years. The tumors were located mainly in the lower extremities (83%), and the median tumor size was 9.5 cm. Sixteen tumors showed low cellularity (70%), and eight tumors had high mitotic activity (more than two per 10 high-power fields). The tumors were immunoreactive for vimentin (89%), synaptophysin (72%), epithelial membrane antigen (28%), and S-100 protein (17%). Nine tumors were diploid, three aneuploid, and one tetraploid. Mean Ki-67 activity was 11% (range, 1 to 45%). The 10-year overall survival rate was 78%. On univariate analysis, tumor size > or = 10 cm, high cellularity, presence of anaplasia or rhabdoid features, mitotic activity more than two per 10 high-power fields, Ki-67 > or = 10%, and Ki-67 "hot spot" > or = 25% were associated with decreased metastasis-free or overall survival. Ploidy status was not associated with any adverse outcome. The presence of any of these adverse prognostic factors can indicate the possibility of a more aggressive behavior in extraskeletal myxoid chondrosarcoma, and a closer follow-up is suggested.

Fibroma of tendon sheath involving the patellar tendon.

Fibroma of tendon sheath is a benign soft-tissue tumor that usually arises in association with tendons or ligamentous structures. We describe, what is, to the best of our knowledge, the first reported case of fibroma of tendon sheath involving the patellar tendon.

Nonrhabdomyosarcoma soft tissue sarcomas in children. The Mayo Clinic experience.

Eighty-six children to 18 years of age were treated for nonrhabdomyosarcoma soft tissue sarcomas of the trunk and extremities. Synovial sarcoma (31), fibrosarcoma (13), malignant fibrous histiocytoma (11), epithelioid sarcoma (10), and clear cell sarcoma (7) were the most common diagnoses. Four patients presented with metastatic disease. A high percentage of patients presented after biopsy by the referring physician, although this could not be shown to affect outcome. Patients were treated with wide removal of the tumor when possible, with judicious use of adjuvant radiation, or with chemotherapy in selected cases. Mean followup was 11 years. Five- and 10-year survival was 92% and 84%, respectively. Tumors larger than 5 cm were associated with a worse prognosis. When compared with published data in adults, the prognosis of primary, localized nonrhabdomyosarcoma soft tissue sarcomas in children appears to be more favorable.

Extraction of a supracondylar nail through the proximal femur during total hip arthroplasty.

With the increasing popularity of supracondylar femoral intramedullary nails, removal of these devices may become necessary during total hip arthroplasty. The present article describes a technique for extracting these nails in a retrograde fashion through the proximal femur, thus sparing the patient a knee arthrotomy.

Malignant lesions arising in chronic osteomyelitis.

Neoplasia occurring in a sinus tract is a well known complication of chronic osteomyelitis. Previous series have been too small to permit survival analysis. Fifty-three consecutive patients (44 men and 9 women) from the authors' institution were reviewed, including 24 who previously were reported. There were 50 patients with squamous cell carcinomas, one with fibrosarcoma, one with myeloma, and one with lymphoma. Mean age was 59 years. One patient sought treatment elsewhere and was lost to followup. Forty-four patients underwent amputation, and eight underwent limb salvage. Followup averaged 9 years. Of 50 patients with squamous cell carcinoma, five died of disease. Overall survival in this group was not statistically different from that expected for age matched controls. Despite the low grade nature of most of these lesions, amputation often is chosen as the most reliable means of treating the tumor and the chronic infection.