Mark C. Leeson

Thermal aspects of the use of polymethylmethacrylate in large metaphyseal defects in bone : a clinical review and laboratory study

The potential necrotizing effects of the heat produced by the exothermic polymerization process has raised questions regarding the use of polymethylmethacrylate (PMMA) in orthopedic surgery. An experimental model was used to: (1) analyze the amplitude and distribution of heat in bone taken from autopsy specimens when large metaphyseal defects (simulating tumor excision) were filled with curing PMMA and (2) to observe any significant necrotizing temperatures. The experimental design included two experimental groups of five distal femora into which either a small- or large-bore defect was made in the lateral epicondylar region. These defects were filled with either one or two packs of PMMA cement, and temperature probes were used to record temperature elevations at the cement core, the bone-cement interface, and the surrounding 1-, 2-, 3-, and 5-mm bone intervals. To simulate physiologic temperature and fluid environment, the experiment was conducted in a 37 degrees normal saline bath. There is clinical evidence suggesting that the large amounts of PMMA used in tumor reconstructive surgery (often two packs or more) may lead to thermal necrosis of remaining tumor cells in the curetted cavity. This may explain, at least in part, the decrease in recurrence of giant-cell bone tumor after curettage and PMMA cementation.

Treatment of advanced metastatic lesions of the acetabulum using the saddle prosthesis

Current methods of treating advanced patients with metastatic periacetabular disease are complex and result in high complication rates. The purpose of this study was to show whether the implantation of the saddle prosthesis would serve as an additional tool to help treat metastatic disease in these patients. From 1991 to 2003, 20 patients with advanced metastatic periacetabular lesions (Harrington Class III) were treated using the saddle prosthesis. Goals of surgery were a decrease in pain, functional restoration, and ambulation. The mean age was 61 years. Average length of followup was 20 months. Postoperatively, ambulation was achieved in 16 of 20 patients. There were four postoperative complications (20%) in three patients. Surgical goals were met in 18 of 20 patients. The MSTS–ISOLS emotional score was 2.9 of 5. The average total MSTS–ISOLS score was 16.6 of 30 (55%). Using the Allan scoring system consisting of analgesia, independence and ambulation, and mobility, all scores had significant improvements postoperatively. Careful surgical indications and technique should result in a stable, functional reconstruction allowing patients the ability to ambulate outside the house with a cane. Patients can expect to be emotionally satisfied with the procedure while using nonnarcotic analgesia and can expect an improved quality of life despite bone metastasis.

Primary amyloidoma of the spine. A case report and review of the literature

Primary amyloidosis of bone is a rare disease process. When amyloid lesions do occur in bone, they are often associated with myeloma or other plasma cell dyscrasias. Because of Its rarity and its protean clinical and radiographic picture adequate biopsy tissue for histopathologic studies is essential for accurate diagnosis. This case presents a 43-year-old man with nondescript back pain and an impressive radiographic lesion in his lower thoracic spine demonstrating the need for careful diagnostic evaluation and a high incidence of suspicion. When occurring primarily in a localized anatomic area, the prognosis for survival is excellent, and cure can be expected by local excision and reconstruction, as necessary.

Thermal Aspects of the Use of Polymethylmethacrylate in Large Metaphyseal Defects in Bone

The potential necrotizing effects of the heat produced by the exothermic polymerization process has raised questions regarding the use of polymethylmethacrylate (PMMA) in orthopedic surgery. An experimental model was used to: (1) analyze the amplitude and distribution of heat in bone taken from autopsy specimens when large metaphyseal defects (simulating tumor excision) were filled with curing PMMA and (2) to observe any significant necrotizing temperatures. The experimental design included two experimental groups of five distal femora into which either a small- or large-bore defect was made in the lateral epicondylar region. These defects were filled with either one or two packs of PMMA cement, and temperature probes were used to record temperature elevations at the cement core, the bone-cement interface, and the surrounding 1-, 2-, 3-, and 5-mm bone intervals. To simulate physiologic temperature and fluid environment, the experiment was conducted in a 37 degrees normal saline bath. There is clinical evidence suggesting that the large amounts of PMMA used in tumor reconstructive surgery (often two packs or more) may lead to thermal necrosis of remaining tumor cells in the curetted cavity. This may explain, at least in part, the decrease in recurrence of giant-cell bone tumor after curettage and PMMA cementation.

Late-onset tibia vara: a histopathologic analysis. A comparative evaluation with infantile tibia vara and slipped capital femoral epiphysis

Histopathologic and histochemical studies were performed on the entire physes and contiguous structures of five knees (three patients) with late-onset tibia vara (Blounts disease). A constellation of abnormalities of both medial and lateral physeal components resulted in disorganization and misalignment of the physeal zones. The changes were remarkably similar to those observed in both infantile tibia vara and slipped capital femoral epiphysis, suggesting a common etiology. Our evaluation indicates that asymmetric compressive and shear forces acting across the proximal tibial physis effect its disruption and causes suppression and deviation of normal endochondral ossification, thereby resulting in tibia vara.

Soft-Tissue Myxomas and Fibrous Dysplasia of Bone: A Case Report and Review of the Literature

An association between fibrous dysplasia and myxomas (soft-tissue neoplasms of mesenchymal origin) has been described in the literature. The authors report another such case of fibrous dysplasia/myxoma coexistence: a patient with polyostotic fibrous dysplasia who developed right anterior thigh pain from a solitary intramuscular myxoma. After a thorough review of the literature, the authors found that a causal relationship between fibrous dysplasia and myxomata remains uncertain. To ensure an adequate and accurate diagnosis, however, patients with soft-tissue myxomas should be thoroughly evaluated for fibrous dysplasia. A proper investigation of soft-tissue masses also should be carried out to exclude malignancy.

Primary epiphyseal transplants and bone overgrowth in childhood amputations

Seventeen children aged newborn to 14 years underwent major through-bone amputations or revision at our two institutions. Ten patients (group 1) had primary autogenous epiphyseal transplants taken from the amputated limb and used to cap the open medullary canal of the residual limb. Seven patients (group 2) did not have epiphyseal transplants. Nine of 10 patients in group 1 (90%) had no problems related to bone overgrowth or delay in prosthetic fitting. In group 2, six of seven patients (86%) had clinically symptomatic bony overgrowth of 20 months after the index amputation on the average. Four patients had surgical revisions. Therefore, provided healthy autogenous donor epiphyses are available, we recommend primary epiphyseal transplants to avoid the complications of bone overgrowth in childhood through-bone amputations.

Ganglioneuroma of the Sacrum

Ganglioneuromas (GNs) are benign, slow-growing, rare soft-tissue tumors that arise from the sympathetic nervous system and comprise less than 1% of all soft-tissue neoplasms. Although GNs are slow-growing, they can and will invade bone and pressure local adjacent structures by their continued growth. In a 20-year-old woman, GN produced a large presacral mass. This case illustrates the diagnostic features at various stages of growth, histopathology, and treatment of GN.

Eosinophilic granuloma of bone in the growing epiphysis.

Eosinophilic granuloma of bone is a rare skeletal manifestation of one of the spectrum of diseases known as histiocytosis X. These lesions often simulate other pathophysiologic processes (Ewing sarcoma, chronic osteomyelitis, Brodie abscess, and chondroblastoma) and may present significant diagnostic problems. Three additional cases of eosinophilic granuloma in an epiphysis are reviewed in this report. Transphyseal extension was present in all our cases and in five of 10 cases documented in the literature. Diagnosis demands accurate biopsy and histopathologic evaluation. Treatment and prognosis are individualized.

Unique size and location of a glomus tumor with a review of the literature

Glomus tumors are a tumor of perivascular, temperatureregulating bodies; 75% occur in the hand, 50% of these are subungual, and 50% occur with erosion of the distal phalanges. They are typically less than 1 cm in diameter. The tumor may often present as a small, bluish-red nodule. Nail ridging is a common finding. Magnetic resonance imaging (MRI) is helpful in making the diagnosis. Treatment is marginal excision.