Inflammatory pseudotumor of nerve.

Two cases of inflammatory pseudotumor are described. The first patient, a 35-year-old white man, developed a progressive sensorimotor deficit in the right leg associated with a fusiform sciatic nerve mass in the posterior thigh. The lesion, compressive in nature and situated entirely within the epineurium, was totally resected. Histology revealed lymphocytic and plasmacellular inflammation as well as extensive fibrosis and collagen deposition. The patchy infiltrate consisted equally of CD2, CD3, CD5, and CD7 positive T-lymphocytes as well as CD20-and CD22-positive B-lymphocytes expressing both kappa and lambda immunoglobulin light chains. A selective biopsy of the encompassed and compressed nerve fascicles demonstrated both myelin loss and axonal injury. The second case was that of an 18-year-old woman with focal enlargement of a radial nerve by an epineurial infiltrate of multinucleate histiocytes and T as well as occasional B lymphocytes. No etiology was apparent in either case. The differential diagnosis includes non-neoplastic processes (amyloidoma and tuberculoid leprosy) as well as tumors (benign and malignant peripheral nerve sheath tumors, lymphoma). Although rare, inflammatory pseudotumors must be included in the differential diagnosis of tumor-like lesions of peripheral nerve.

Thigh injuries in athletes.

The thigh, which consists of the heavily muscled region around the femur, is vulnerable to many types of athletic injury. This review addresses the assessment, prevention, and rehabilitation of both the common thigh injuries associated with participation in sports, such as contusions and myositis ossificans traumatica, and a few relatively uncommon but diagnostically important entities that sports physicians must recognize when an athlete has pain or dysfunction attributable to the thigh. Dividing the thigh into anatomic compartments aids in both differential diagnosis and understanding of the pathomechanics that lead to injury. Rehabilitation is especially emphasized because improper selection of modalities or misuse of exercise can seriously impede or worsen recovery. Conversely, the use of appropriate rehabilitation principles and new concepts in exercise prescription can decrease morbidity and lead to rapid resumption of sports.

Injuries in youth ice hockey: a pilot surveillance strategy.

OBJECTIVE: To determine the incidence and type of injuries in youth hockey players during practice and games as well as to test the applicability of the current methods to a national surveillance study of youth hockey injuries. DESIGN: During the 1993 to 1994 season, we undertook a prospective observational analysis of youth hockey players on four competitive teams at three levels of participation: Squirt, Peewee, and Bantam. MATERIAL AND METHODS: In a study group of 66 youth hockey players, types and anatomic sites of injury, mechanisms of injury, player position affected, and occurrence of injuries during practice or games were determined and analyzed statistically. An injury was strictly defined, standardized reporting strategies were used, and a single physician examined all injured athletes and made the diagnoses. RESULTS: A total of 14 injuries occurred during the season. The on-ice injury rate (per 1,000 player-hours) was 1.0 at the Squirt level (ages 9 and 10 years), 1.8 at the Peewee level (ages 11 and 12 years), and 4.3 at the Bantam level (ages 13 and 14 years). No game injuries and only one mild practice injury occurred in Squirt players (N = 16), and only two mild injuries occurred during practice sessions for Peewees (N = 17). No differences were noted between practice injury rates at the various levels; all recorded game injuries occurred only in Bantam players (N = 33). The most common types of injuries were contusions, fractures, strains, and sprains. The arm and shoulder were most frequently injured. CONCLUSION: Further research is necessary to determine whether injuries in youth ice hockey can be reduced by changes in playing rules, enforcement of existing rules, improvements in protective equipment, alteration in coaching techniques, and institution of educational programs.

Chondromyxoid fibroma of bone: a clinicopathologic review of 278 cases.

In a study of the clinical, radiographic, and pathological features of chondromyxoid fibroma, the tumor was slightly more common in men, usually in the second decade of life. Almost half of the tumors involved the long bones, although the ilium and the small bones were also common sites. Roentgenograms showed a sharply marginated, lobulated, lucent defect in the metaphysis. The tumor involved the medullary bone in an eccentric fashion, and the cortex was thinned and expanded. Periosteal reaction and soft tissue extension were uncommon. Mineralization was identified in 13% of the lesions. Histologically, the tumors were almost always arranged in lobules, which were prominent (macrolobular) or somewhat indistinct (microlobular). The tumor cells were spindle-shaped or stellate and arranged in a myxoid matrix. Calcification was seen in more than one third of the cases but was rarely prominent. Hyaline cartilage and chondroblastoma-like areas were not uncommon. Approximately 18% of tumors showed bizarre nuclei. Permeation of bony trabeculae was uncommon. Treatment was conservative surgical removal; approximately one fourth of the patients had recurrence.

Well-differentiated liposarcoma. The Mayo Clinic experience with 58 cases.

The clinicopathologic results from 58 patients with well-differentiated liposarcomas are reported. Thirty-two tumors involved the extremities, 20 the retroperitoneum, 4 the scrotum, 1 the abdominal wall, and 1 the cheek. Most tumors were large (mean, 22.6 cm). There were 31 (53%) lipoma-like, 23 (40%) sclerosing, and 4 (7%) primary dedifferentiated tumors. Six tumors underwent dedifferentiation after recurrence. The average follow-up period was 9.3 years. Thirty-seven patients (64%) were alive with no evidence of disease; 7 (12%) were alive with disease; 8 (14%) died of disease; and 6 (10%) died of other causes. Dedifferentiation did not indicate imminent death; 5 of the 10 patients were alive with no evidence of disease. Three dedifferentiated tumors subsequently recurred as pure well-differentiated liposarcomas. Patients with extremity tumors had a significantly better prognosis than those with retroperitoneal or scrotal tumors (P = .006). Extremity tumors treated by wide local excision recurred in only 11% of cases, whereas 60% of those treated by marginal or simple excision recurred.

Repeat cDNA synthesis and RT-PCR with the same source of RNA.

A simple method has been developed that enables reextraction of RNA from an RNA-cDNA mixture. The reextracted RNA was converted to cDNA followed by polymerase chain reaction (PCR). Thus, cDNA synthesis (followed by PCR) was carried out two times on the same source of RNA. The method has been applied to 40 RNA samples of diverse tissue origin with a success rate of 100%. Thus, the method offers more versatile use of small but valuable RNA sources than currently possible.

High temperature cDNA synthesis by AMV reverse transcriptase improves the specificity of PCR.

The enzyme avian myeloblastosis virus reverse transcriptase (AMV-RT) is routinely used for cDNA synthesis, which is generally carried out at temperatures between 37 degrees C and 42 degrees C. We show that this enzyme can support cDNA synthesis, at temperatures as high as 70 degrees C. We have utilized this property of the AMV-RT to improve the specificity of polymerase chain reaction (PCR). Furthermore, this apparently thermophilic property of the enzyme, which is an important constituent of a mesophilic organism, raises intriguing questions regarding evolution of the enzyme structure.

Mechanical evaluation of six types of reconstruction following 25, 50, and 75% resection of the proximal femur.

The structural stiffness and the stiffness of the osteotomy site after six types of reconstruction of the proximal femur were compared by testing in axial compression, mediolateral bending, and axial torsion in a canine model. An osteotomy was carried out for 25, 50, or 75% of the length of each femur, and the proximal portion was replaced by one of five allograft/endoprosthetic composites or a segmental replacement. The reconstructions included (a) a composite press-fit proximally and cemented distally, (b) a composite cemented proximally and distally, (c) a composite cemented proximally and fixed with two plates at the allograft-host bone interface, (d) a composite cemented proximally and secured distally with bicortical screws, (e) a composite secured proximally and distally with bicortical screws, and (f) a segmental prosthesis cemented into the distal femur. The results showed that the segmental reconstruction and the reconstruction with double-plate fixation and a cemented endoprosthesis were structurally stiffer and had greater stiffness of the osteotomy site than the other reconstructions. In comparison, reconstructions that involved cement alone or cement and press-fit techniques generally were more compliant than the others, both structurally and at the osteotomy site.

Mechanical characteristics of proximal femoral reconstruction after 50% resection.

Six techniques of proximal femoral replacement were compared in vitro with the use of compression, bending, and torsional testing in a canine model. One femur of each pair was osteotomized in the midshaft region, and the proximal portion was replaced with one of six techniques. These techniques included (a) a segmental proximal femoral endoprosthesis cemented into the distal femur with no allograft (technique ES); (b) a long-stem endoprosthesis press-fit into an allograft and cemented into the distal femur with a transverse osteotomy (technique AT); (c) the same construct as technique AT, but with a step-cut at the osteotomy (technique AS); (d) a long-stem endoprosthesis interlocked into an allograft and cemented into the distal femur with a transverse osteotomy (technique AI); (e) a short-stem endoprosthesis cemented into an allograft combined with one plate laterally stabilizing the allograft to the distal femur with a transverse osteotomy (technique AP1); and (f) the same construct as technique AP1, but with an additional plate cranially (technique AP2). A long-stem endoprosthesis cemented into the contralateral intact femur served as the control. Techniques that involved a long-stem endoprosthesis and cementing distally (AT, AS, and AI) were more resistant in torsion than the plated replacement techniques (AP1 and AP2). The segmental replacement construct (ES) was equal to or stronger than all other techniques under each testing condition. In torsion, the addition of a step-cut (AS) significantly lowered angular displacement of the reconstruction when compared with the reconstruction with a transverse osteotomy (AT) (p < 0.05). Bones with one-plate fixation (AP1) were significantly weaker in torsional stiffness and maximum torque and in mediolateral bending (p < 0.05) than all other techniques. The addition of a second plate (AP2) increased the mechanical properties of the construct so that it was greater than the one-plate method and was equal to (bending and compression) or still weaker (torsion) than the other techniques. The results indicate that segmental replacement methods and allograft/endoprosthetic composites that involve long-stem endoprostheses fixed with cement are mechanically superior to methods that involve short-stem endoprostheses with single or double plating at the osteotomy sites.

Evidence for the upregulation of osteogenic protein-1 mRNA expression in musculoskeletal neoplasms.

Little is known about bone and cartilage tumors at the molecular level; thus, the identification of genes associated with these tumors may be useful as markers and therapeutic targets. To address this issue and to test the hypothesis that abnormal expression of one or more growth factors in the transforming growth factor-beta superfamily is associated with musculoskeletal neoplasia, degenerate primers based on the conserved sequences in these genes were made for screening tumor samples by reverse transcription-polymerase chain reaction. First, these primers were used to obtain a comparative profile between a low-grade chondrosarcoma and its dedifferentiated high-grade counterpart in the same patient. This experiment identified an amplified DNA product in the high-grade sample that was identical to osteogenic protein-1/bone morphogenetic protein-7. Osteogenic protein-1 mRNA expression was 17-fold greater in this high-grade sample than in the low-grade one. Osteogenic protein-1 was highly expressed (three of three) in human osteosarcoma cell lines but was not expressed (zero of four) in normal osteoblast samples. Screening for gene expression of osteogenic protein-1 in 57 osteosarcomas and chondrosarcomas indicated that 44% (range: 38-52%) of them were positive for osteogenic protein-1 mRNA. Screening of breast and prostate tumors revealed a similar association with osteogenic protein-1 mRNA expression.

A mechanical comparison of gluteus medius attachment methods in a canine model.

Seven techniques of gluteus medius attachment were compared in vitro in a canine model. Four methods were used for tendon to tendon attachment: (a) two modified Bunnell-Mayer sutures, (b) two Kessler locking loop sutures, (c) two horizontal mattress sutures, and (d) two sutures with a looped suture technique. The two methods of tendon to bone attachment were repair with a 1 cm spiked staple and repair with a spiked washer and screw, and the method of bone to bone attachment involved two figure-eight cerclage wires. The contralateral limb served as a control. Compared with the bone to bone attachment, the four tendon to tendon attachments and the two tendon to bone attachments had significantly less strength (31 and 30% of the ultimate load for bone to bone repair, respectively) and tensile stiffness (24 and 39% of the tensile stiffness for bone to bone attachment, respectively) (p < 0.0001). The control specimens were significantly stronger and stiffer than all specimens (p < 0.05) except those that had bone to bone fixation. There were no significant differences among the four tendon to tendon suture repairs with regard to either strength or stiffness; the values ranged from 28-45% of those of the controls. Among the tendon to bone repairs, fixation with a spiked washer and screw was significantly stronger than that with a spiked staple (p = 0.032), but there was no difference between these two techniques with regard to stiffness.

Effect of cisplatin chemotherapy on extracortical tissue formation in canine diaphyseal segmental replacement.

The reconstruction of large bone and joint defects after the resection of malignant tumors remains a major challenge. Chemotherapy has significantly lowered the risk of metastasic disease, but complications associated with reconstructive techniques continue to result in late morbidity. In the present study, biomechanical torsion testing, gait analysis, and histomorphometric and scanning electron microscopic evaluations of 24 dogs were used to examine the effects of preoperative and postoperative administration of cisplatin on the biologic fixation of a porous-coated segmental replacement prosthesis. The chemotherapy consisted of four cycles of cisplatin administered at a dosage of 75 mg/m2 preoperatively or postoperatively. The healing was enhanced by use of an autogenous corticocancellous bone graft. The graft was placed evenly around the prosthesis and the adjacent femoral cortex. Mechanical analyses of torsional stiffness, yield strength, and maximum strength revealed no statistically significant differences between the groups at 12 weeks. Such lack of difference was mainly due to the penetration of highly organized fibrous tissue into the porous surface; this provided strong fixation of the implant to bone even in the absence of bone ingrowth. Although bone ingrowth into the prostheses was not affected, electron microscopic, histomorphometric, and radiologic analyses showed a clear difference in the formation of new bone around the prosthesis. Preoperative chemotherapy did not alter the formation of new bone, but specimens from animals treated postoperatively with cisplatin showed significantly less bone graft resorption and less new bone formation. Hence, the effect of cisplatin administration caused only a temporary delay, not a permanent effect, on extracortical capsule formation. The formation of extracortical bone and soft tissue might prevent debris-incised osteolysis and, therefore, prevent late complications by forming a tight capsule around the bone-prosthetic interface.

Comparison of healing of allograft/endoprosthetic composites with three types of gluteus medius attachment.

This study compared three methods of gluteus medius tendon attachment to an allograft/endoprosthetic composite of the proximal 25% of the femur in a canine model. The three methods were bone to bone, tendon to bone, and tendon to tendon attachment. In an in vivo study, 24 dogs were assigned to three groups of eight dogs each, and serial radiography and weight-bearing analyses were performed throughout the study. The dogs were killed at 6 months, and the specimens were tested in tension to failure and were analyzed histologically. In an in vitro study, each repair was done on six limbs, with a contralateral limb serving as a control for each. In these specimens, the bone to bone attachments were significantly stronger (99.1% of the controls) than the tendon to bone attachments (71.8% of the controls) and the tendon to tendon attachments (40.0% of the controls); there were no differences in tensile stiffness among the three types of attachment. By 6 months, the tensile strength of the tendon to tendon attachments increased significantly and that of the tendon to bone attachments decreased significantly. There were no significant differences in tensile strength among the three types of attachment. The tensile stiffness of the bone to bone attachments (91.0% of the controls) was significantly greater than that of the tendon to bone attachments (40.8% of the controls) but not significantly different from that of the tendon to tendon attachments (63.2% of the controls). The bone to bone attachment was associated with increased bone resorption, bone remodeling, and bone porosity, accompanied by thinner allograft cortices, when compared with the other types of attachment. In dogs with a bone to bone attachment, weight-bearing increased more slowly than in dogs with either of the other two attachments. These changes associated with the bone to bone attachment may merely be secondary to healing of the bone to bone attachment to the greater trochanter; therefore, they may only be temporary phenomena or they may be the portents for long-term complications. Longer term studies of at least 1-2 years must be performed before these questions can be answered.

Comparison of allograft/endoprosthetic composites with a step-cut or transverse osteotomy configuration.

This study was designed to compare the biomechanical and functional characteristics of allograft/endoprosthetic composites of the proximal 25% of the femur repaired with either a transverse or a step-cut osteotomy, using a canine model (10 dogs, five with each type of osteotomy). Serial radiography and weight-bearing studies were performed monthly, and mechanical testing was done 6 months after surgery. The femora were tested in torsion and compared with the contralateral control (insertion of a femoral component but no osteotomy). At 6 months, the composites with a step-cut osteotomy had 36% greater structural stiffness than the composites with a transverse osteotomy (p < 0.005) and 121% greater maximum torque at failure than the controls (p < 0.005), without greater structural stiffness. Evaluation of peak vertical ground reaction forces revealed significantly greater weight-bearing on the experimental limb in dogs with a transverse osteotomy. The results of this relatively short-term study were mixed. Despite the increased structural stiffness of the allograft/endoprosthetic composite with a step-cut osteotomy, the dogs with this type of reconstruction had decreased weight-bearing throughout the course of the study. The step-cut osteotomy may augment the stability of the allograft/endoprosthetic composite, allowing faster healing (as demonstrated by the results of mechanical testing), but in some way, not understood, may cause pain in the reconstructed limb. Longer term studies are needed to answer these questions and to determine whether alteration of the traditional transverse osteotomy has any advantage.

Condensing osteitis of the clavicle. A review of the literature and report of three cases.

Condensing osteitis of the clavicle is a rare and benign idiopathic entity that is probably degenerative or mechanical in etiology. It is usually seen in women of late child-bearing age as a variably painful and tender swelling over the medial end of the clavicle. Radiographs show sclerosis and slight expansion of the medial one-third of the clavicle. Although malignant tumor of bone must be considered in the differential diagnosis of a disease that has such radiographic findings, numerous and expensive screening tests for a presumed primary malignant lesion are not recommended for most patients. It is recommended, however, that an excisional or (preferably) incisional biopsy be performed in all patients unless pain is insignificant and the clinical presentation strongly supports the diagnosis of condensing osteitis. Many patients who have slight pain do not need treatment. Anti-inflammatory medications are variably effective. Patients in whom the lesion is refractory respond well to excision of the medial one-third of the clavicle.

Metastases from histologically benign giant-cell tumor of bone.

Metastasis from a giant-cell tumor of bone that is histologically benign has become a recognized entity. To date, thirty-one pathologically proved cases have been reported in the world literature. To this, we add eight cases from our experience of more than 400 cases of histologically benign giant-cell tumor of bone. The lungs are the principal site of metastasis, the lesions being pathologically indistinguishable from the primary tumor. The metastatic process is unpredictable as to clinical aggressiveness, and the mortality rate is approximately 25 per cent. We advise aggressive attempts at complete extirpation of metastases.

Vascularized free fibular transfer combined with autografting for the management of fracture nonunions associated with radiation therapy.

BACKGROUND: The purpose of this study was to evaluate the functional results, rates of union, and complications associated with vascularized free fibular transfer combined with autografting for the treatment of nonunions in previously irradiated bone. METHODS: Seventeen patients who had had eighteen vascularized free fibular transfers combined with autografting for the treatment of nonunion of a fracture in previously irradiated bone were included in this study. There were eleven female patients and six male patients. Eight patients had a bone neoplasm and nine, a soft-tissue neoplasm. The diagnosis was Ewing sarcoma in four patients; lymphoma, malignant fibrous histiocytoma, and rhabdomyosarcoma in two patients each; and cavernous hemangioma, metastatic breast carcinoma, reticulum-cell sarcoma, myxosarcoma, hemangiopericytoma, and fibrosarcoma in one patient each. The remaining patient had a soft-tissue tumor for which the diagnosis was not known. All patients received radiation therapy. The average dose was 5564 centigray. There were no recurrent tumors. The average interval between the radiation therapy and the original fracture was 111 months. The fracture was in the femur in thirteen patients, in the humerus in three, and in the tibia in one. All patients had operative or nonoperative treatment, or both, of the initial fracture, and two had iliac-crest bone-grafting after the initial open reduction and internal fixation procedure. The ages of the patients ranged from thirteen to eighty-two years at the time of the vascularized free fibular transfer. All fibular transfers were applied as onlay grafts because no nonunion was associated with a large segmental defect. Cancellous autogenous bone graft from the iliac crest was used as an additional graft at the proximal and distal junctions of the graft with the bone and at the fracture site in all patients. The average duration of follow-up after the vascularized free fibular transfer was fifty-seven months (range, twenty-eight to 112 months). RESULTS: Sixteen of the eighteen fracture sites united, after an average of 9.4 months (range, three to twenty-four months). Thirteen patients had an excellent result, one had a good result, two had a fair result, and one had a failure of treatment. Four patients had an infection, including one who continued to have a nonunion. The other three patients had union after treatment with antibiotics, debridement, and removal of the hardware. Another patient who had a recalcitrant nonunion eventually required an above-the-knee amputation. CONCLUSIONS: On the basis of this review, we suggest that microvascular fibular transfer combined with autografting is an appropriate treatment option for difficult nonunions associated with previously irradiated bone.

Extra-abdominal desmoid tumors.

One hundred and ninety-four patients with extra-abdominal desmoid tumors, most of them in the extremities, have been treated at the Mayo Clinic. One hundred and thirty-two patients (68 per cent) experienced a recurrence at an average of 1.4 years after the first treatment. A greater tendency for recurrence was evident in female patients, in patients who were more than thirty years old, in certain anatomical locations (especially the foot and calf), and most importantly after treatment by intralesional or marginal excision. In view of the excellent prognosis for survival, we recommend wide local excision when anatomically feasible or marginal excision and postoperative radiation therapy when function of the extremity would be severely compromised if excision with wide margins were done. A recurrent lesion that does not appear to be growing should be followed until evidence of growth of the lesion precipitates a secondary wide excision.

Secondary malignant giant-cell tumor of bone. Clinicopathological assessment of nineteen patients.

Twenty-six patients who had a malignant giant-cell tumor of bone--a sarcoma either juxtaposed to a zone of typical benign giant-cell tumor or occurring at the site of a previously documented benign giant-cell tumor--have been seen at the Mayo Clinic. Of the twenty-six tumors, nineteen were secondary to a previous attempt at local control of a benign giant-cell tumor. All but one of these nineteen patients with a secondary tumor had received therapeutic irradiation four to thirty-nine years earlier. The nature and duration of the symptoms and the sites of predilection of the malignant giant-cell tumors were the same as for benign giant-cell tumor. Fibrosarcoma occurred three times as frequently as osteosarcoma. The best results of treatment of the secondary sarcoma were obtained with early ablation.

Unilateral facet dislocation of the cervical spine. An analysis of the results of treatment in 26 patients.

Twenty-six patients with unilateral facet dislocation of the cervical spine were analyzed to determine the best method of treatment of this injury, the incidence of late pain and instability, and the indications for surgical stabilization. This review showed that all patients with a unilateral facet dislocation of the cervical spine should be treated initially with halo traction in an attempt to obtain reduction. If reduction is obtained, then nonoperative treatment in the form of a halo thoracic apparatus may be the best method of treatment. Failure to obtain reduction with axial traction is an indication for open reduction and one-level posterior cervical fusion. Patients left in the displaced position and allowed to heal in that position usually develop late pain as a complication of this method of treatment.