Evaluation of bone-grafting materials in a new canine segmental spinal fusion model

This paper describes a new canine segmental spinal fusion model for the comparison of bone-grafting materials. The test sites in the model are three separate posterior interfacet-interlaminar fusion sites in the lumbar spine (L1-2, L3-4, and L5-6). The outcome was assessed by scoring of the fusion sites for union and by mechanical testing of fused segments. The results from two experiments are presented. Autogenous cancellous bone was the most effective material tested and had a statistically superior score for union compared with all other materials (p = 0.01). The results with an osteoconductive matrix of collagen and ceramic alone were no better than those with the controls (no graft). However, addition of an extract of matrix-derived proteins (15-30 kDa) to the collagen-ceramic carrier appeared to improve the score for union. The inclusion of nonresorbed ceramic granules had no evident effect on the mechanical properties of fusions, with a comparable score for union. This model appears to be a sensitive and efficient method for the comparison of graft materials. Advantages over previously described models are discussed.

Studies of the mechanism by which the mechanical failure of polymethylmethacrylate leads to bone resorption

The purpose of this study was to examine the relationship between the mechanical failure of polymethylmethacrylate and bone resorption at the bone-cement interface of a prosthesis. Evaluation of tissue that had been retrieved from the cement-bone interface of eighteen femoral components of total hip prostheses that were loose without associated infection revealed that a critical factor associated with bone resorption was the presence of particles that were small enough (one to twelve micrometers) to be phagocytized by macrophages. To study this phenomenon in vitro, macrophages in tissue culture were exposed to three preparations of polymethylmethacrylate cement. A novel method of cement preparation was used with control for solid and soluble contaminants, which provided a sensitive and specific technique for the determination of which mediators were released from the macrophages. Electron microscopy demonstrated phagocytosis of particles of less than twelve micrometers in size, regardless of the type of cement preparation. Exposure to all three cement preparations resulted in toxicity, as reflected by inhibition of 3H-thymidine incorporation. Exposure also led to increased release of tumor necrosis factor, but none of the three preparations resulted in release of prostaglandin E2. Division of the cement preparations into two groups on the basis of the size of the particles demonstrated that exposure to particles that were small enough to be phagocytized led to inhibition of 3H-thymidine incorporation and release of tumor necrosis factor, while exposure to particles that were too large to be phagocytized did not. Neither exposure to small particles nor exposure to large particles of cement led to release of prostaglandin E2. Our results show that when the mechanical failure of cement produces particles that are small enough to be phagocytized, phagocytosis of the particles results in the increased production of tumor necrosis factor by the macrophages, which may in turn lead to bone resorption and prosthetic loosening. These small particles also decrease 3H-thymidine uptake by the macrophages.

Management of extremity soft-tissue sarcomas

Management of extremity soft-tissue sarcomas requires accurate clinical staging, pathologic diagnosis, surgical resection with a wide margin, and adjuvant radiation therapy for high-grade lesions. Brachytherapy offers a clean benefit in local control for large (> 5 cm) high-grade sarcomas. The role of radiation therapy for small high-grade and all low-grade soft-tissue sarcomas still is being evaluated. Survival is function of histologic grade, age of patient, size and location of the tumor, metastases, and adequacy of the surgical resection. Efficacy of chemotherapy has yet to be proven.

A PCR-based linkage map of human chromosome 1

A genetic linkage map of human chromosome 1 based entirely on PCR-typable markers has been developed using 38 simple sequence repeat (SSR) polymorphisms. These SSRs include 36 dinucleotide repeats and 2 tetranucleotide repeats. The average heterozygosity at these markers was 0.73 and ranged from 0.52 to 0.95. Multipoint linkage analysis was used to develop a map of these 38 markers in which the relative placement of each locus is supported by likelihood odds > 1000:1. This PCR-based map was anchored at the centromere by the D1Z5 alpha-satellite polymorphism, and the ends of the map were defined by D1Z2 and D1S68, which are the most distal loci in the CEPH consortium map of chromosome 1. The sex-averaged, male, and female maps extend for 328, 273, and 409 cM, respectively. The average distance between markers on the sex-averaged map is 8 cM, and the largest interval is 32 cM. This map of highly informative PCR-based markers will provide a rapid means of screening human chromosome 1 for the presence of disease genes.

The healing of segmental bone defects, induced by recombinant human bone morphogenetic protein (rhBMP-2). A radiographic, histological, and biomechanical study in rats

Subcutaneous implants of a recombinant human form of the bone-inducing protein rhBMP-2 (recombinant human bone morphogenetic protein-2) in rats have resulted in the local induction of endochondral bone formation. To test the osteoinductive activity of rhBMP-2 in an osseous location, we created five-millimeter segmental defects in the femora of forty-five adult male Sprague-Dawley rats. Two doses of lyophilized rhBMP-2 (1.4 or 11.0 micrograms) were implanted in each defect, together with guanidine-hydrochloride extracted demineralized rat-bone matrix as a carrier, and the results were compared with those in rats that had implantation of guanidine-hydrochloride extracted demineralized rat-bone matrix only. The formation and healing of bone were determined by radiographic, histological, and mechanical analysis. Both doses of rhBMP-2 induced formation of endochondral bone in the osseous defects in a dose-related manner. Implantation of 11.0 micrograms of rhBMP-2 yielded significant (p less than 0.05) bone formation, resulting in radiographic, histological, and mechanical evidence of union. Despite new-bone formation in the defects that had received 1.4 micrograms of rhBMP-2, no instances of union were observed.

Newest factors in fracture healing

Natural selection has evolved a process of fracture healing that is characterized by callus formation and is enhanced by physical loading and motion at the fracture site. Internal fixation of fractures alters the biology of fracture healing, especially when rigid fixation using plates is performed. Intramedullary nails that allow some motion and loading usually are associated with callus formation. Plates that practically eliminate interfragmentary motion, however, prevent external periosteal callus formation. Primary osteonal healing can occur with plate fixation, but if interfragmental gaping of greater than 1 mm exists, delayed healing occurs. Closed treatment of fractures occasionally results in nonunion. In addition, physicians' high expectations for skeletal restoration have prompted vigorous research in areas of bone grafting, graft substitutes, and analysis of local and systemic factors that regulate fracture healing. A better understanding of the activity of bone morphogenetic protein and growth factors, such as transforming growth factor beta, will allow manipulation of the biology of healing to enhance the surgical treatment of skeletal trauma.

Soft-tissue management with prosthetic replacement for sarcomas around the knee

The soft-tissue management was reviewed in 46 consecutive primary and nine revision segmental knee resections with prosthetic reconstruction performed for sarcomas around the knee. From January 1983 until August 1986, before the extensive use of free-tissue transfer in these patients, 20 primary segmental knee reconstructions were performed with five patients receiving gastrocnemius rotation flaps, and one patient receiving a late free flap (Group I). In this group, three patients were converted to an above-knee amputation because of wound problems. From August 1986 to August 1988, free-tissue transfer was available and extensively used in addition to rotation flaps to manage 26 primary (Group II) and nine revision (Group III) segmental knee reconstructions. In contrast to Group I, none of the patients in Groups II or III required amputation or conversion to a nonlimb-sparing procedure for soft-tissue management. None of the patients in this study received radiation therapy to their extremities. Chemotherapy protocols were similar in Groups I and II with 22 of 26 patients in Group I and 19 of 20 in Group II receiving treatment. The availability and expertise to perform free and rotational flaps at the time of initial excision provides greater selection and improved outcome for those patients whose wounds are closed primarily. The capability to perform free and rotation flaps at initial resection and for postoperative wound management is a major determinant of ultimate success in patients having reconstruction after excision of sarcomas about the knee.

Survival, prognosis, and therapeutic response in osteogenic sarcoma. The Memorial Hospital experience

Two hundred seventy-nine consecutive patients with Stage II osteogenic sarcoma of the appendicular skeleton treated between 1976 and 1986 were studied to identify predictors of long-term survival. Survival was 77% and 73% at 5 and 10 years, respectively, with continuously disease-free survival being 70% and 69%. On univariate analysis, the most significant predictors of survival were the location of the primary lesion, local control of the tumor, and the degree of necrosis in the primary tumor after intravenous neoadjuvant chemotherapy (histologic response). On initial multivariate analysis, similarly, only location and histologic response to chemotherapy predicted disease-free outcome. After statistical control for local recurrence, only histologic response to chemotherapy was retained as an independent predictor, suggesting that in this data set, the location of primary lesion exerted its effect only secondarily through its association with the ability to provide local control. The risk of local recurrence was almost fivefold higher in tumors of the femur than in tumors of other locations (relative risk, 4.6) and, within the femur, was more than threefold higher in the proximal femur than in the distal femur (relative risk, 3.4). None of the other primary tumor or patient characteristics studied yielded independent predictive significance for survival. The rate of failure was almost fivefold as high in those with an incomplete response to chemotherapy compared with those with a complete response to chemotherapy (relative risk, 4.9; 95% confidence interval, 2.2 to 11). Even in those patients with minimal or no necrosis in the primary tumor, ultimately 62% and 54% were disease-free at 5 and 10 years, respectively.

Primary skeletal non-Hodgkin's lymphoma in the pediatric age group

The authors discuss rare primary skeletal non-Hodgkin's lymphoma in 16 patients treated from 1973 to 1989. The symptoms of these patients related to bone lesions in 95% of the cases. These bone lesions were monostotic or polyostotic, with or without regional and distant metastases. The locations of these lesions were long bones in 13 patients, pelvic bones in seven patients, and skull and vertebral bodies in two patients. The anatomical locations of these lesions in the bones were diaphysis alone in one patient, epiphysis in two patients, metaphysis in three patients, and a combination of diaphyseal, epiphyseal, and metaphyseal lesions in seven patients. Extraskeletal involvement was present in nine patients; extraskeletal sites included regional or distant lymph node involvement in seven cases, the mediastinum in two, lung nodules in two patients, the skin and subcutaneous regions in four patients; bone marrow in three patients, and peripheral nervous system (PNS) in one patient. Two patients had stage I disease, three had stage II disease, eight had stage III disease, and three had stage IV disease. The majority of patients had large noncleaved cell diffuse lymphomas or DHL by Rappaport classification. All patients were treated with the LSA2-L2 protocol; six patients received radiation therapy to the affected bone, and ten patients received no radiation therapy. Three patients failed on treatment within the first 4 months of therapy. Two patients developed a second tumor, one in the radiation therapy field and the other in a patient who received no radiation therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of propranolol on bone metabolism in the rat

Propranolol, a nonspecific beta-blocker has many physiologic effects. Its effects on bone in vivo are unknown, although beta receptor sites have been found on osteoblasts. In this study, the hypothesis tested was that low doses of propranolol could alter bone properties and enhance orthotopic endochondral bone formation. In a group of nonsurgical rats, propranolol treatment increased femoral torsional strength on biomechanical testing. In the rat surgical model used, right femora were fixed to a polyethylene plate and then defects were created mid-diaphysis and subsequently filled with demineralized bone matrix. These rats (defect rats) were randomly divided into groups that were given propranolol or a saline carrier for 19 consecutive days. In the defect rats, increased trabecular femoral metaphyseal mineral apposition rates were observed in propranolol-treated groups. Densitometry and roentgenographic scoring of callus formation after 12 weeks in propranolol-treated rats revealed increased callus and bone union. The results of this study indicate that propranolol treatment can significantly affect bone properties.

Stage IIB osteogenic sarcoma

Two hundred seventy-one consecutive patients treated from 1976 through 1986 were reviewed to estimate long-term survival. Disease-free survival for the entire cohort was 77% at five years and 74% at ten years. Humeral lesions had the best probability of survival (84% at ten years), followed by tibial lesions (81%) and femoral lesions (67%). Histologic response to preoperative chemotherapy was the strongest predictor of outcome. Those with little response had a survival estimate of 54% at ten years as compared to 68% for partial responders and approximately 90% for complete responders. Local recurrence was seen in 6.6% and was associated with an adverse effect on survival. Only two of the 18 patients with local recurrence have been rendered long-term disease-free survivors.

Multiple giant cell tumors and Paget disease of bone: radiographic and clinical correlations

The clinical and radiographic findings of four patients with multicentric giant cell tumor (GCT) of bone and Paget disease were retrospectively reviewed. Three patients underwent magnetic resonance (MR) imaging evaluation; all patients underwent computed tomography (CT). The MR characteristics of the bone component in pagetic GCT appeared to reflect the pagetic phase; a sclerotic pattern was largely represented by hypointense marrow signal intensity on images obtained with both long and short repetition times (TRs) and echo times (TEs). Conversely, a tumor appearing in a mixed pagetic phase demonstrated more heterogeneous signal intensity with all pulse sequences. Extensive soft-tissue components, noted in all cases, showed largely intermediate signal intensity on short TR/TE images and foci of increased signal intensity on longer TR/TE images. In most cases, dramatic reduction in tumor bulk was noted with the use of steroids alone. An awareness of this entity is important because the appearance of lytic lesions with soft-tissue extension in patients with Paget disease does not necessarily imply a grave prognosis. Serial CT or MR imaging is helpful in monitoring the remissions and exacerbations that reflect response to therapy in Paget disease and GCT.

Breast-feeding among women attending women, infants, and children clinics in Georgia, 1987

Breast-feeding is an important determinant of the health and nutritional status of children, particularly in lower socioeconomic populations. A major goal of the Georgia Special Supplemental Food Program for Women, Infants, and Children (WIC) is to increase the practice of breast-feeding among the women it serves. Breast-feeding practices were determined among a random sample of 404 women from a cohort of 2010 who attended WIC prenatal clinics in Georgia in 1986 and were expected to deliver in February 1987. Respondents were interviewed 6 months postpartum. Of these women, 24% initially breast-fed, but only 6% continued for 6 months or longer. The initiation of breast-feeding was associated with greater maternal education and with being married. The adjusted odds of breast-feeding for mothers who were married or living as married were 3.0 (95% confidence interval, 1.7 to 5.3) times greater than for mothers who were not married or living as married. Mothers with more than 12 years, 12 years, or 10 to 11 years of education were 5.2 (1.8 to 15.3), 2.7 (1.0 to 6.9), and 2.5 (0.9 to 6.9) times more likely, respectively, to breast-feed than mothers with 9 or fewer years of education. After adjustment was made for marital status and education, the remaining variables (ethnicity, parity, age, and employment status) did not influence the initiation of breast-feeding in this low-income population. The need for vigorous promotion of breast-feeding by the Georgia WIC program is emphasized by the low rate of initiation and short duration of breast-feeding in this low-income population.

Prosthetic arthroplasty of the knee after resection of a sarcoma in the proximal end of the tibia. A report of sixteen cases

The results of a specific type of prosthetic reconstruction of the knee (total replacement arthroplasty) after resection of a sarcoma of the proximal part of the tibia in sixteen patients were retrospectively reviewed. The diagnosis was stage-IIB osteogenic sarcoma in nine patients, stage-IIB malignant fibrous histiocytoma in three patients, and stage-IB sarcoma of various types in four patients. The length of tibial resection ranged from 100 to 257 millimeters. Of the eleven patients who were available for functional examination (mean duration of follow-up, sixty-three months), three patients had an excellent result, seven had a good result, and one had a fair result. Of the five patients who were not available for functional testing, one who was doing well was lost to follow-up at eighty months, one had died of metastases at sixteen months, and three had had a secondary amputation for infection or for loosening of the prosthesis.

Biochemical and genetic characterization of the HBA71 Ewing's sarcoma cell surface antigen

Monoclonal antibody HBA71 detects a cell surface antigen of human Ewing's sarcomas and peripheral neuroepitheliomas that distinguishes these tumors from other small round cell tumors of childhood and adolescence. In the present study, we show that monoclonal antibody HBA71 reacts with polypeptides of Mr 32,000 and 30,000 and that the HBA71-coding gene segregates with human chromosomes X and Y in rodent-human hybrids. Therefore, we compared HBA71 to the T-cell leukemia antigen 12E7, which is encoded by the pseudoautosomal region of chromosomes X and Y. We show that monoclonal antibodies HBA71 and 12E7 (a) detect polypeptides of identical size, (b) react with mouse cells transfected with complementary DNA corresponding to the 12E7-coding gene, MIC2, and (c) give similar patterns of reactivity with human tumor cell lines and small round cell tumor tissues. Thus, HBA71 and 12E7 are identical or closely related antigens and the available MIC2 probes will facilitate analysis of the molecular mechanisms that determine differential HBA71 expression in small round cell tumors of childhood and adolescence.

The effect of chemotherapy on growth in the skeletally immature individual

One hundred twenty-two children with nonmetastatic osteogenic or Ewing's sarcoma were studied to assess the effect of multiagent adjuvant chemotherapy on skeletal growth and final stature. No deviations from the height distributions of a normal population were noted at diagnosis. There was a marked retardation of linear growth during the year of intensive chemotherapy. Only 15% of the patients grew at the expected rate during that year. The distribution of nutritional status scores was significantly different at the end of the first year than at baseline. The distribution of ultimate height scores was significantly different than the baseline distribution. The overall final distribution was also significantly different from the normal population expectation. Any absolute difference in height, however, is likely to be small. The subgroups that were observed to full adult stature showed mean heights of 162 cm for girls and 176 cm for boys.

The Van Nes tibial rotationplasty. A functionally viable reconstructive procedure in children who have a tumor of the distal end of the femur

Twelve patients who had a malignant tumor of the distal end of the femur were treated with a Van Nes tibial rotationplasty. The survival rates were comparable with those for above-the-knee amputees and patients who had an endoprosthetic replacement. The results of functional testing showed that these patients performed as well as those who had endoprosthetic replacement and better than those who had above-the-knee amputation. Rotationplasty is therefore a favorable alternative to amputation or endoprosthetic replacement, either as a primary or as a salvage procedure.

Percutaneous bone marrow grafting of delayed union and nonunion in cancer patients

Bone marrow is a source of osteoprogenitor cells that are key elements in the process of bone formation and fracture healing. Eight patients with primary sarcomas treated by extensive en bloc resections and reconstruction using internal fixation who developed delayed unions or nonunions were treated by injection of autogeneic bone marrow into the site of failed healing. Five of the eight patients received chemotherapy, with one patient receiving radiation therapy in addition. Bone formation was noted in seven patients after injection. Union was achieved in five of the patients. These results, obtained in difficult clinical circumstances, are encouraging and suggest that autogeneic bone marrow grafting is a useful technique in the treatment of delayed unions and nonunions and warrant further clinical studies.

New advances and concepts in amputee management after treatment for bone and soft-tissue sarcomas

Amputation is still necessary to achieve disease-free margins in some patients with osteogenic sarcoma. Improving the quality of life for this largely young patient population has become increasingly important considering the dramatic increase in their survival rate. A multidisciplinary approach should include prosthetic devices that are comfortable and lightweight, and produce an energy-efficient gait, an aggressive postoperative rehabilitation, and an objective evaluation of progress. This approach will help improve the high net energy expenditure of ambulation and the asymmetrical stance time experienced by this group of individuals and allow them to gain equal status in society.

Paget's disease of bone

Paget's disease of bone is defined as a process of increased bone remodeling; the primary event is increased resorption (osteoclastic activity) followed by subsequent reactive bone formation (osteoblastic activity). It is usually asymmetric and may be asymptomatic. The etiology is unknown, but recent evidence appears to support the theory that a virus is an important etiologic factor. It may present with a wide variation in the clinical and radiographic picture. The most frequent sites of involvement include the spine, femora, cranium, pelvis, and sternum. The most common complaints are pain, skeletal deformity, and change in skin temperature. Pathologic fractures may be the presenting manifestations or complications in a patient with known Paget's disease. They occur most frequently in the long weight-bearing bones of the lower extremities such as the femoral neck and subtrochanteric and tibial regions. The two major therapeutic agents available for treatment are calcitonins (porcine, salmon, or human) and diphosphonates. The aim of such therapy is to control the metabolic activity of the disease, to normalize the biochemical parameters, and to improve the symptoms. Fortunately, tumors are rare; early diagnosis may give rise to more effective palliation, if not a significant cure rate.

Treatment of pathologic fractures of the distal femur with the Zickel supracondylar nail

Thirteen patients with 14 pathologic, supracondylar, and distal femoral fractures were evaluated retrospectively. The Zickel supracondylar device was easy to use and applicable to a wide range of clinical problems. It provided good functional and symptomatic results in 11 of 14 cases. Two patients required a removal of metal implants due to soft-tissue irritation. Attention to the detail of insertion of the Zickel device may prevent complications.