A comparative analysis of subchondral replacement with polymethylmethacrylate or autogenous bone grafts in dogs

A comparative analysis was made of subchondral replacement with polymethylmethacrylate and autogeneic bone grafts in defects in the medial femoral condyles of dogs. The defect produced a 50% reduction in subchondral stiffness. An in vitro preparation helped establish that subchondral stiffness returned to normal after reconstruction with polymethylmethacrylate. The in vivo model demonstrated a reduction in subchondral stiffness in both groups at three weeks, but the bone grafted side returned to normal and the methylmethacrylate side recovered to 79% of the control at 12 weeks. There were no deleterious effects on the articular cartilage in either group when analyzed histologically and biochemically. A marked increase in new bone formation and subchondral porosity was found in the polymethylmethacrylate groups. This study supports the clinical use of subchondral polymethylmethacrylate after the exteriorization and curettage of benign bone tumors such as giant cell tumors.

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.

The effects of therapeutic doses of irradiation on experimental bone graft incorporation over a porous-coated segmental defect endoprosthesis

The incorporation of autogeneic bone graft into a porous coated segmental endoprosthesis after high-dose irradiation was studied in dogs. A mid-diaphyseal defect was surgically created and then reconstructed with a porous-coated segmental endoprosthesis in 16 dogs. Autogeneic bone grafts were placed over the porous-coated regions of the endoprosthesis and at the endoprosthesis-bone junctions to achieve extracortical fixation. In eight dogs, the reconstructed femora were treated with a time-equivalent dose of 5500 cGy, delivered over a five-week period, beginning three weeks after surgery. In eight dogs, which served as the control group, the reconstructed femora were not irradiated. Dogs were killed 12 weeks after surgery, and the reconstructed femora were evaluated clinically, roentgenographically, mechanically, and histologically. Extracortical bone formation and bone ingrowth into the porous-coated segmental endoprosthesis were significantly inhibited by high-dose irradiation. Nonirradiated reconstructed femora had higher maximum torque at the implant-bone junction than irradiated femora. Nonirradiated femora had significantly greater bone ingrowth within the porous space than irradiated femora. Intracortically, irradiated femora had greater unlabeled bone and less porosity as well as more new bone than nonirradiated femora at 12 weeks postsurgery. Extracortically, irradiated femora had greater original cortical bone and less porosity as well as more new bone than nonirradiated femora at 12 weeks postsurgery. Mineral apposition was less in the irradiated femora from the initiation of radiotherapy to the time of killing five weeks after cessation of irradiation.

General perspectives, pathogenesis, pathophysiology, and skeletal dysfunction

A better understanding of the pathogenesis and pathophysiology of the metastatic process is leading to improvements in diagnosis and treatment. Evaluation of specific areas of disorder of skeletal function, including hematopoiesis, mineral metabolism, and structural support, is important. Continued developments are necessary to minimize or prevent effects on the skeleton related to the metastatic process.

Metastatic bone disease: current concepts of clinicopathophysiology and modern surgical treatment

Metastases to bone are a common problem confronting both the orthopaedic oncologist and cancer specialists. Early diagnosis requires a knowledge of the pathogenesis of bone metastases. A primary route of metastatic cells is via Batson's vertebral vein plexus. An understanding of the pathophysiology enables the surgeon to plan effective treatment. As many patients continue to survive for prolonged periods following the detection of bone metastases, it is important to plan treatment that is durable and functional. Non-operative treatment is utilised for small lesions (less than 25 percent of the cortical diameter). Radiotherapy (generally 3000 cGy in ten fractions), patient education (to avoid excessive torsional loads), and systemic chemotherapy or hormonal therapy are the mainstays of non-operative treatment. The indications for surgical treatment include: (1) lesions greater than 50 percent the diameter of the cortex, (2) permeative lesions in high stress areas (subtrochanteric region of the hip, mid-femoral diaphysis, mid humeral metaphysis), and (3) lesions in which pain persists following external beam irradiation. Early and effective treatment improves the remaining quality of life in patients with metastatic bone disease. A knowledge of the pathogenesis and pathophysiology aids the clinician in making an early diagnosis.

Survival and management considerations in postirradiation osteosarcoma and Paget's osteosarcoma

Postirradiation and Paget's osteosarcomas are high-grade malignancies. The five-year survival was only 10% in recent experience at the author's institution. Progressive pain is an important clinical feature in both conditions. Careful roentgenographic studies demonstrate cortical destruction and a soft-tissue mass in virtually all patients. Metastasis was present in 25% of both groups of patients at presentation. In contrast to previous series, more than 80% of the patients with postirradiation osteosarcoma had had irradiation for malignant entities and more than 70% had been treated with modern radiotherapy regimens (cobalt-60 or linear accelerator). Twice as many patients with postirradiation osteosarcoma were evaluated and treated in the 1980s than in the previous decade. The initial indication for irradiation often was carcinoma of the breast, uterus, or cervix, or lymphoma. Two-thirds of the patients had progressive disease that was not controllable within six months after diagnosis. Early detection may be the only effective means of improving survival with postirradiation or Paget's osteosarcoma. These patients require lifelong follow-up evaluations.

Metastatic bone disease. A study of the surgical treatment of 166 pathologic humeral and femoral fractures

A retrospective study of the surgical treatment of 166 metastatic lesions of the humerus and femur in 147 patients was performed. There were 106 women and 41 men whose average age was 62 years. Two-thirds of the patients were treated for complete fractures, while one-third were treated for impending fractures. Breast, lung, and kidney carcinoma accounted for the majority of the primary lesions. One-half of the patients died within nine months of surgery, while one-quarter were alive 19.1 months after surgery. The patients with breast cancer had the best prognosis, while the patients with lung cancer had the worst. The probability of implant failure increased linearly with time to 33% at 60 months. The probability of failure for the femoral lesions was greater, with 44% at 60 months. The average survival in the patients with failed fixation in the femoral lesions was 34.5 months with a mean interval to failure at 17.7 months. The failure rate was high (23%) in proximal femoral lesions treated with a compression screw or nail plate. Common reasons for failure included poor initial fixation, improper implant selection, and progression of disease within the operative field. Bone cement augmentation should be used with the fixation device when possible. Complications due to hip-screw cut-out from the head may also be reduced by applying bone cement around the screw threads.

Metastatic diaphyseal fractures of the shaft of the humerus. The structural strength evaluation of a new method of treatment with a segmental defect prosthesis

The surgical treatment of extensive metastatic diaphyseal lesions of the humerus with pathologic fractures is difficult. Patients with failed internal fixation often have large segments of bone loss. Rigid fixation often is not possible in these cases. Four patients were treated with a titanium segmental defect (SD) prosthesis with good clinical results. A comparative in vitro analysis of fixation with the SD prosthesis, a Rush rod, and a dynamic compression plate (DCP) augmented with methylmethacrylate was performed. The SD prosthesis performed better than the Rush rod and DCP in both the nondestructive four-point bending test and the destructive torsional test. The reconstructed humeri using the SD prosthesis had a torsional strength approaching that of an intact specimen. Hence, the SD prosthesis is a useful adjunct device in treating patients with extensive destructive lesions of the humerus secondary to metastatic disease and hematologic malignancies and in patients with malignant diseases who have had failed attempts at internal fixation.

Primary malignant bone tumors of the hand

Malignant bone tumors of the hand are rare and few centers have extensive experience in the care of patients with these lesions. Eighteen patients with 22 lesions were evaluated at our institution. There were nine chondrosarcomas, four hemangioendothelial sarcomas, two cases each of osteosarcoma and fibrosarcoma, and a single case of Ewing's tumor. The average age of the patients was 39 years. Ten lesions each were located in the metacarpals and phalanges, with two lesions in the carpus. There were nine local recurrences, which appeared at an average of 24.5 months (range, 3 to 74 months). Curettage procedures resulted in the highest rate of local recurrence (85%). Three patients died of metastatic disease. Surgical control of these lesions requires careful preoperative planning and wide surgical margins. Regular oncologic follow-up is necessary.

Extraosseous Ewing's sarcoma. A study of 42 cases

Fifty patients at the Mayo Clinic (Rochester, MN) from 1935 to 1985 met the histologic criteria for extraosseous Ewing's sarcoma. Forty-two had soft tissue primaries without bony involvement and formed the basis for this retrospective study of the clinical behavior and management of extraosseous Ewing's sarcoma. There were 19 male and 23 female patients (mean age, 22 years). Metastases were documented in 30 of the patients, six at the time of presentation and 24 occurring up to 11 years later, most commonly to lungs or bone. Three patients were lost to follow-up. Sixteen of 35 patients (46%) had local recurrence. Overall survival was 15 of 39 (38.5%) at 5 years. Decreased survival was noted with pelvic tumors, incomplete resections, and presence of metastatic disease, whereas increased survival was associated with wide surgical resection with negative microscopic margins, adjuvant local radiation therapy, and presentation since 1970 (48% 5-year survival compared with 28% before 1970).

Extraosseous Ewing's sarcoma. A study of 42 cases

Fifty patients at the Mayo Clinic (Rochester, MN) from 1935 to 1985 met the histologic criteria for extraosseous Ewing's sarcoma. Forty-two had soft tissue primaries without bony involvement and formed the basis for this retrospective study of the clinical behavior and management of extraosseous Ewing's sarcoma. There were 19 male and 23 female patients (mean age, 22 years). Metastases were documented in 30 of the patients, six at the time of presentation and 24 occurring up to 11 years later, most commonly to lungs or bone. Three patients were lost to follow-up. Sixteen of 35 patients (46%) had local recurrence. Overall survival was 15 of 39 (38.5%) at 5 years. Decreased survival was noted with pelvic tumors, incomplete resections, and presence of metastatic disease, whereas increased survival was associated with wide surgical resection with negative microscopic margins, adjuvant local radiation therapy, and presentation since 1970 (48% 5-year survival compared with 28% before 1970).

Solitary plasmacytoma of bone: Mayo Clinic experience

A review of 46 cases of solitary plasmacytoma of bone was undertaken in an attempt to better define the clinical features and prognostic indicators associated with this disease. Criteria for inclusion in the study included the following: (a) solitary lytic bone lesion on skeletal survey; (b) histologic confirmation of the lesion; and (c) bone marrow plasmacytosis of less than 10 percent. Patients with extramedullary plasmacytomas and osteosclerotic lesions were excluded. All patients were evaluated with serum and urine protein studies at the time of diagnosis. The median follow-up was 90 months with a minimum of 30 months. Fifty-four percent of the lesions involved the vertebral column. The thoracic spine was the single most commonly involved site (13/46 patients). The initial lesion was treated with radiotherapy in all but three patients in whom complete surgical resection was achieved. Total doses ranged from less than 20 Gy to 70 Gy with a median of 39.75 Gy. Overall, 54% developed multiple myeloma, 2% failed with new bone lesions without multiple myeloma, and 11% developed local recurrences. No patient receiving 45 Gy or more to the solitary lesion had a local failure. While the median time to progression was 18 months, 23% of the failures occurred after 60 months. The five local failures occurred at 7, 12, 18, 40, and 114 months. The overall survival was 74% at 5 years and 45% at 10 years. The 5- and 10-year disease-free survivals, however, were 43 and 25%, respectively. Evidence of abnormal serum and/or urine protein was found in 25 of 46 patients. Neither survival nor disease-free survival was significantly influenced by the presence of abnormal proteins even if they persisted after irradiation.

Aneurysmal bone cyst: clinicopathologic features and treatment of ten cases involving the hand

Ten cases of aneurysmal bone cyst in the hand were identified among 208 such lesions in our institutional files. The patients (six women and four men) had a mean age of 27.3 years. Two patients had open physes. Seven lesions were in the metacarpals. Radiographic examination showed that in all cases the lesion was both expansile and completely lucent. There were no recurrences in the three patients treated by complete excision and bone grafting. Curettage and bone grafting in seven cases was associated with four recurrences. Three of these four local recurrences were treated successfully with curettage procedures. Treatment of aneurysmal bone cysts of the small bones of the hand requires either thorough exteriorization, curettage, and bone grafting or excision and bone grafting.

Prosthetic replacement of the femoral head for fracture of the femoral neck in patients who have Parkinson disease

A retrospective study was performed of forty-nine patients (fifty fractures of the femoral neck) who had Parkinson disease and who had had an endoprosthetic replacement of the femoral head. The average age of the patients was seventy-four years (range, forty-seven to ninety-two years). All of the fractures were Garden Stage III or IV. An anterolateral surgical approach was used in twenty-five hips; a posterior approach, in twenty hips; and a transtrochanteric approach, in five hips. An adductor tenotomy was required in five patients to release an adduction contracture. Ten patients died by the sixth postoperative month. The remaining thirty-nine patients were followed for a minimum of two years (average, 7.3 years). Common postoperative complications were infection of the urinary tract (20 per cent) and pneumonia (10 per cent). There was only one dislocation. At the time of writing, nineteen (80 per cent) of the surviving patients could walk.

Treatment of chronic perilunate dislocations

Fifteen patients with 16 perilunate dislocations that had been untreated for a minimum of 6 weeks after the injury were evaluated after subsequent treatment at a mean of 6.4 years. The median time from injury to definitive treatment was 17 weeks. Ten wrists had completely ligamentous injuries and six had fracture-dislocations. Treatment consisted of open reduction and internal fixation in six patients, isolated carpal bone excision in four, wrist arthrodesis in two, proximal row carpectomy in two, and bilateral carpal tunnel release in one. In this series the results of excision of the lunate or scaphoid alone were uniformly poor. One of the two patients who had a proximal row carpectomy required secondary radial styloidectomy, and a pseudarthrosis developed in one of the two patients who had a wrist arthrodesis. All six patients treated by open reduction and internal fixation had satisfactory outcomes and none required additional surgery.

Hibernoma. A case report

Hibernoma is a rare soft-tissue tumor clinically presenting as a firm, freely movable, nontender mass, most commonly in the interscapular region. It is slow growing and usually asymptomatic. Examination of the overlying skin may demonstrate evidence of hypervascularity. On gross examination, the tumor is encapsulated and highly vascular, with its color varying from tan to reddish brown. Microscopic examination is usually diagnostic, demonstrating the characteristic multivacuolated oval or polygonal cells. Because of its benign character, treatment consists of simple excision. This article describes a case of a patient with hibernoma.

Primary malignant bone tumors of the shoulder girdle: surgical technique of resection and reconstruction

Limb ablation for tumors of the shoulder is a devastating procedure. Recent advances in preoperative investigative measures, adjuvant chemotherapy, and reconstructive techniques have resulted in an increased interest in limb-sparing resection. For limb-sparing procedures to present a viable alternative in these cases, recurrence rates must be comparable to those obtained with ablative surgery. In addition, the resection must result in an improvement over the status obtainable with prosthetic devices. Twenty-four patients underwent limb-salvage procedures of various forms for primary bone tumors of the shoulder girdle. At follow-up (average: 33 months), 19 patients were alive without disease, one was alive with disease, and four were dead. One patient had local recurrence. All surviving patients enjoyed nearly normal function of the distal extremity. Improvements in techniques of soft tissue reconstruction in an effort to gain function and stability after wide resection of these tumors are necessary. Results indicate that these limb-salvage attempts offer successful alternatives to mutilating and crippling proximal amputations of the upper extremity.

Dedifferentiated chondrosarcoma. A report of the clinicopathological features and treatment of seventy-eight cases

Dedifferentiated chondrosarcoma is a highly malignant variant of chondrosarcoma. Approximately 11 per cent of chondrosarcomas can be expected to dedifferentiate into more anaplastic lesions. In this report, we analyze the clinicopathological features and treatment of seventy-eight lesions of this type. The ages of the patients ranged from nineteen to eighty-two years (average, 54.6 years). The cartilaginous precursor was central in most patients. Eleven of the lesions developed in the site of a previously resected low-grade chondrosarcoma. Dedifferentiation was from low-grade chondrosarcoma to osteosarcoma in forty-two patients, to fibrosarcoma in thirty-three, and to malignant (fibrous) histiocytoma in three. Perforation of the cortex and a soft-tissue mass were found in most of the patients. Widespread metastatic disease within two years after resection was a frequent finding. The over-all five-year-survival rate was 10.5 per cent. Any potential for a "cure" is related to early diagnosis and adequate surgical treatment by amputation or resection.

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.