Oncogenic osteomalacia associated with soft tissue chondromyxoid fibroma.

Oncogenic osteomalacia is a rarely described clinical entity characterized by hypophosphatemia, phosphaturia, and a low concentration of 1,25-dihydroxyvitamin D(3). It is most often associated with benign mesenchymal tumor and can be cured with surgical removal of the tumor. In this paper, we present a case of oncogenic osteomalacia caused by chondromyxoid fibroma in the soft tissue of the sole of the foot in a 56-year-old woman.

Competitive exclusion against Salmonella gallinarum of Salmonella enteritidis infected chickens.

To evaluate the degree of competitive exclusion against Salmonella gallinarum(S. gallinarum) of Salmonella enteritidis(S. enteritidis) infected chickens, fifty-six, 4-week old Hyline layer suspected of S. enteritidis infection were challenged with S. gallinarum. All chickens were tested for S. enteritidis isolation using cloacal swabs and serum plate agglutination test using S. enteritidis Ag. before challenge and classified into four groups(SE isolated, SE nonisolated, SE seropositive and SE seronegative). None of the SE isolated and the SE seropositive groups died after challenge and the average weight gains were 245.5g and 254.6g, respectively. But in the SE nonisolated and the SE seronegative groups, mortality was 18.2% and 20.6% and the average weight gains were 150.1g and 111.2g. The incidence of reisolation of S. gallinarum of the SE isolated and the SE seropositive groups were 41.7% and 47.6% from liver, 33.3% and 47.6% from spleen and 8.3% and 14.3% from cecum, respectively, and the SE nonisolated and the SE seronegative group were 63.6% and 64.7% from liver, 84.1% and 88.2% from spleen and 47.7% and 52.9% from cecum. The serological response of the SE isolated and the SE seropositive groups hardly changed from 75.0 and 81.8% before challenge to 75.0 and 85.7% after. But, the other two groups were found to be significantly higher after challenge and increased from 0 and 18.2% to 100%. Consequently, S. enteritidis preinfected chickens were found to be significant different in terms of mortality, weight gain, reisolation of S. gallinarum and serological response compared to noninfected chickens. Moreover, our study shows that S. enteritidis infected chickens appear strong competitive exclusion against the colonization of S. gallinarum.

Arthroplasty of the hip in patients with aplastic anemia.

BACKGROUND: Patients with aplastic anemia are now living longer and therefore are at increased risk for the development of osteonecrosis of the hip. However, studies on the results of arthroplasty for the treatment of osteoarthritis of the hip in patients with aplastic anemia are lacking. METHODS: Twenty-six primary hip prostheses (one bipolar prosthesis fixed with cement, two bipolar prostheses fixed without cement, three hybrid total hip prostheses, and twenty total hip prostheses fixed without cement) were implanted, between March 1990 and May 1992, in nineteen patients who had been diagnosed with aplastic anemia. A specific prospective protocol was followed for the perioperative transfusion of platelets and blood. Twenty-five hips were replaced because of osteonecrosis of the femoral head, and one was replaced because of a femoral neck fracture. The patients were followed prospectively, with preoperative and serial postoperative Harris hip ratings as well as radiographs, for a minimum of six years or until death. RESULTS: No patient had excessive perioperative bleeding or a postoperative infection. After a mean duration of follow-up of seventy-nine months (range, seventy-two to ninety-five months), two patients had died with the original implant in place. No patients were lost to follow-up. The mean Harris hip score was 55 points (range, 42 to 68 points) preoperatively and 87 points (range, 56 to 95 points) at the time of the latest follow-up. At the time of this writing, no hip had been revised. One patient with a bipolar prosthesis had radiographic evidence of femoral loosening and will probably require revision. A second patient had some medial protrusion of a bipolar prosthesis, with mild symptoms. All of the acetabular components that had been fixed without cement and all of the other femoral components appeared to be stable on radiographs after a minimum of seventy-two months of follow-up. CONCLUSIONS: Total hip arthroplasty can be performed safely in patients with aplastic anemia. In the present intermediate-term study, the durability of implant fixation was maintained and the clinical results demonstrated a sustained increase in function of the hip.

Volumetric change of the graft bone after intertransverse fusion.

STUDY DESIGN: Patients in whom good intertransverse fusion had been achieved were selected for the volumetric study of the fusion mass using sequential computed tomography scans. OBJECTIVES: To assess the natural volumetric change of intertransverse fusion mass and the effect of the disease entity and spinal instrumentation on the fusion mass volume. SUMMARY OF BACKGROUND DATA: The magnitude of volumetric change of the graft bone after intertransverse fusion is still inconclusive. METHODS: Fifteen adult patients who underwent decompression surgery with single-level lumbar and lumbosacral intertransverse fusion were selected for this study. Preoperative diagnoses were degenerative spondylolisthesis in nine patients and isthmic spondylolisthesis in six. Seven of the 15 patients received pedicle screw fixation. They were categorized into two major groups: 1) instrumented and noninstrumented groups and 2) isthmic and degenerative groups. To assess the volumetric change of the graft bone, sequential computed tomography scans were obtained 2 weeks after surgery and again 18 months after surgery. RESULTS: The overall initial mean graft volume was 6251 mm3, which decreased to 2842 mm3 by 18 months after surgery (P < 0.001). The overall mean volume loss between the two periods was 54.8% of the initial graft volume. Although there was no significant difference in the mean graft volume between the groups at either 2 weeks or 18 months after surgery (P > 0.05 in all comparisons), the mean graft volume in each group decreased significantly during the observation period (P < 0.01 in all comparisons). There was no significant difference in the mean volume loss or in the ratio of residual volume to the initial graft volume between the groups during the study period (P > 0.05 in all comparisons). The initial graft volume correlated positively with the graft volume at 18 months after surgery (r = 0.612, P < 0.01) and volume loss (r = 0.949, P < 0.01), but negatively with the residual volume ratio (r = -0.507, P < 0.01). CONCLUSIONS: These results showed that more than one half of the initial graft bone volume was being absorbed during the consolidation processes of the graft bone, and that the volume loss during the period was not significantly affected by the spinal instrumentation or by the disease entity. It was also found that the greater the amount of the initial graft bone, the larger the fusion mass at 18 months after surgery. The volume loss, however, increased proportionally to an increase in the initial graft bone volume. The efficiency (ratio of residual volume to the initial graft volume) of the intertransverse fusion also tended to decline as the initial graft volume increased.

Fate of the facet joints after instrumented intertransverse process fusion.

A success or failure of an intertransverse process fusion has been determined by the fusion status of the intertransverse fusion mass alone, and little consideration has been given to the fusion status of the facet joint. The purpose of this study was to assess the fusion status of the facet joints at the fusion level and its impact on the overall fusion outcome. Sixteen patients (19 levels) treated with decompression and intertransverse process fusion using pedicle screw fixation without facet arthrodesis were entered into a cross sectional study in which the fusion status of the intertransverse fusion masses and facet joints at each fusion level were evaluated and combined at an average duration of followup of 35 months (range, 22-61 months). Union rate of the intertransverse process fusion (58%, 22 of 38) was lower than the spontaneous fusion rate of the facet joint (68%, 26 of 38). However, the combination of the two fusion statuses at each fusion level generated 89% of the overall fusion rate (17 of 19 levels). With surgery, all patients had a good or excellent clinical outcome, but the outcome had no relation to the overall fusion status. The results suggest that the fusion status of the facet joint should be considered in determining overall fusion status after combined decompression with instrumented intertransverse process fusion.

Hydroxyapatite impregnated bone cement: in vitro and in vivo studies.

Hydroxyapatite (HA) particle impregnated polymethylmethacrylate (PMMA) bone cement was fabricated in order to induce bony tissue ingrowth into the pores left behind by resorption of the HA. The amount of HA was 0%, 10%, and 30% by weight. After mixing the HA with bone cement it was cast in a 4 mm inside diameter glass tube (10 mm long). Each specimen was cut into half and used for in vitro and in vivo experiment. Diametral tensile and flexural bend tests were made to evaluate its mechanical properties. SEM (scanning electron microscope) and ESCA (electron spectroscopy for chemical analysis) were used to evaluate the surface characteristics of the specimen. Push-out test and histology studies were made after implanting the specimens for six weeks in the distal portion of rabbit femur. The mechanical test results showed significant decrease of the flexural and diametral tensile strength linear with the increased amount of HA (p < 0.05). The SEM and ESCA analyses showed no definite exposure of HA particles on the surface of the specimens due to the covering by PMMA. The interfacial shear strength of the implanted specimens showed significant increases in the 30% HA specimens compared with the 0% ones but the 10% specimens did not show any difference. Histological observation showed little HA particle apposition to new bone in 10% specimens but more in the 30% ones. In conclusion, this study showed the decreased mechanical properties both by increasing the amount of HA particles and with the bone particles impregnated bone cement. In vivo study showed much lower interfacial shear strength due to implant site compared to other studies but the 30% HA specimens showed statistically significant increase in the push-out strength after implanting into the distal end of rabbit femora.

Posterior instrumentation and anterior interbody fusion for tuberculous kyphosis of dorsal and lumbar spines.

STUDY DESIGN: Thirty-nine adults and five children with active spinal tuberculosis and resulting kyphosis of the dorsal and lumbar spine who had combined posterior instrumentation and anterior interbody fusion were observed to determine whether the corrected spinal deformity could be maintained until solid fusion. OBJECTIVE: To evaluate the effectiveness of the combined two-stage procedure for treating kyphosis due to active spinal tuberculosis. SUMMARY OF BACKGROUND DATA: Until 1970, with all methods of treatment, kyphosis due to active spinal tuberculosis tended to increase during therapy. Most of the patients treated with these methods were not happy with this residual kyphosis, even though their disease was arrested or cured. Kyphosis became their main concern regarding further treatment. METHODS: A combined two-stage procedure, under the cover of 18 months of triple chemotherapy, was used for all patients. For posterior stabilization, the Harrington distraction system, Rush nails or Steinmann pins and wires, and Texas Scottish Rite Hospital instrumentation were used. The diagnosis of successful interbody fusion was made if there was no loss of correction, no graft resorption or graft bed resorption, and if there was visible graft remodeling, such as trabeculation between the graft beds and graft and the graft hypertrophy. RESULTS: In the 39 adults, average preoperative, immediate postoperative, and last follow-up kyphosis angles were 37 degrees, 16 degrees, and 18 degrees, respectively. In four children, the average preoperative, immediate postoperative, and last follow-up kyphosis angles were 55 degrees, 28 degrees, and 31 degrees, respectively. The loss of correction did not exceed 3 degrees. For one-segment spondylodesis, the average fusion times were 4 months in adults and 3.5 months in children. For a two-segment fusion, the average fusion times were 6 months in adults and 6.3 months in children. CONCLUSION: Posterior instrumental stabilization and anterior interbody fusion were found helpful in arresting the disease early, providing early fusion, preventing progression of kyphosis, and correcting the kyphosis.

Meniscal regeneration and its effects on articular cartilage in rabbit knees.

The incidence and size of meniscal regeneration after medial meniscectomy on the right knee and lateral meniscectomy on the left knee of 44 rabbits was observed and correlated with development of degenerative arthritis. Complete meniscal regeneration was found in 23% of medial meniscectomy knees, partial regeneration in 68%, and no regeneration in 9%. Among 44 lateral meniscectomies, only 5% had complete meniscal regeneration, and 68% had no meniscal regeneration. The remaining 27% of knees had partial regeneration. Degenerative changes of articular cartilage in the tibiofemoral joints of all knees were inversely correlated with the size of the regenerated meniscus. These observations suggest that poor results following lateral meniscectomy may be due to a lower level of meniscal regeneration and relatively poor morphological regeneration of the lateral meniscus compared to the medial meniscus.

Conservative treatment of tuberculosis of the thoracic and lumbar spine in adults and children.

We have treated 75 cases of spinal tuberculosis with chemotherapy as outpatients. The drugs used were INH, rifampicin and ethambutol for the 48 adults, and INH, rifampicin and PAS for the 27 children. No operations, apart from the evacuation of large abscesses, were carried out. Every patient was followed up for at least three years and the outcome was judged to be favourable in 95%. This is better than in some series in which radical surgery has been used. Although we recognize the advantages of operation in certain circumstances, we believe that our conservative regimen can be confidently recommended for use in less privileged countries, where adequate facilities for hospital treatment may not be available.

Less rigid internal fixation plates: historical perspectives and new concepts.

In the application of "rigid" plates for diaphyseal fractures, lack of callus healing and overprotection of the underlying bone are viewed by many investigators as undesirable consequences. Potential solutions offered to overcome these deficiencies include modification of the timing of plate removal, use of biologically degradable materials for plates so that stress-shielding can be minimized, and use of less rigid plate fixation systems. This study emphasizes the selection of appropriate design criteria for less rigid plate-fixation systems. To accomplish this goal, the axial, bending, and torsional stiffness parameters are considered in place of the oversimplified terms such as "flexible plate" or "elastic fixation." With the aid of finite element modeling and simplified bench experiments, we performed parametric studies and singled out the plate axial stiffness as the dominant factor in altering the bone stresses. As a result, we designed two experimental plates, one a thin Ti-6Al-4V (titanium with 6% aluminum and 4% vanadium) alloy plate with low stiffness in axial and bending directions, and the other a tubular stainless steel plate with low stiffness in the axial direction but moderate stiffness in bending and torsional directions. The low-stiffness Ti-6Al-4V alloy plate was first tested in a demanding bilateral canine midshaft osteotomy, and proved to be inadequate. Both experimental plates were successful in the unilateral osteotomies, with the tubular plate yielding the best results. After 6 months of plating, the bones beneath the tubular plate had superior mechanical and structural properties as compared to those of the control "rigid" stainless steel and the Ti-6Al-4V alloy plates. Application of this plate prolonged for 9 months did not cause reduction in bone properties and strength. The success of the tubular plate is due to its moderate bending and torsional stiffnesses, which provide adequate fixation to achieve callus union, while its low axial stiffness permits the underlying bone to share the physiological stresses needed for bone remodeling. These drastic changes in mechanical demands on the internal fixation plate during the early healing phase and the postunion remodeling phase are discussed.

Technical aspects of perichondrial grafting in the rabbit.

A screening process to determine the most appropriate model for the study of cartilage growth from perichondrium obtained from the rabbit's left tenth costal cartilage has resulted in the following observations: (1) best growth is achieved when fixation of the graft is secure and conformity to the recipient bed is complete; (2) immobilization enhances fixation, but permits fibrous tissue growth onto the graft, and (3) diminishing periods of immobilization enhance perichondrial growth, but have a deleterious effect on fixation.

Mechanical properties of tendons and ligaments. II. The relationships of immobilization and exercise on tissue remodeling.

The primary goal of this investigation is to study whether soft tissue homeostatic responses secondary to decrease or increase in physiological stress levels and range of motion are a change of mechanical properties or a change of mass, or both. Two experimental animal studies are presented. One is a stress and motion deprivation study by immobilization of a rabbit knee, and the other is an increase in stress and motion study by running exercise of the miniature swine. The findings are that changes in stress and motion significantly altered the tissue properties as well as mass in the case of ligaments and digital extensor tendons. Whereas, no significant changes in properties and mass were detected for the digital flexor tendons. Possible mechanisms of the difference in tissue responses to stress and motion are discussed, and nonlinear relationships between stress and tissue remodeling are suggested.

Anterior interbody fusion in fractures and fracture-dislocations of the spine.

Twenty-five cases of unstable fractures and fracture-dislocations of the spine are reviewed. They were treated at the Catholic Medical College and Centre in a 3-year period, 1975 to 1978. 1. Eleven of the 25 patients were treated by anterior interbody fusion performed at 6 to 8 weeks from injury or initial surgery. 2. Eleven patients had neurological deficits, 3 with incomplete lesions and 8 with complete lesions. Open reduction and decompression laminectomies were performed on patients having neurological deficits prior to anterior interbody fusion. Two patients with incomplete paraplegia showed marked neurological recovery whilst one with complete paraplegia regained some sensation. 3. Solid clinical fusion was obtained in all but one patient within four months of interbody fusion. 4. Amongst the 18 patients with kyphosis at the time of admission 10 had a final improvement of their kyphosis ranging from 3 to 10 degrees (average 6 degrees). Three had no change and 5 demonstrated a mild increase of kyphosis (average 4 degrees). 5. Pain was relieved in 21 patients out of 25. The advantages of this technique include effective stabilization, prevention of late deformity and relatively early mobilization without internal fixation.

Endorphin release: a possible mechanism of acupuncture analgesia.

The action of acupuncture stimulation on analgesia has been investigated. The brain and serum extracts of acupunctured rabbits injected into rabbits produced a marked analgesic effect on the recipient, as shown by a great increase of their pain threshold. This effect is counteracted by a specific opiate anatagonist, naloxone. The data suggest that the release of the endogenous substances with morphine-like biological properties, endorphins, is increased by acupuncture stimulation, thus inhibiting pain perception.