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A solitary intraosseous neurofibroma is rare and mostly occurs in the mandible. We report a case of a solitary intraosseous neurofibroma of the tibia. The radiographic findings were nonspecific and showed an eccentrically located, osteolytic lesion with a thin sclerotic border in the diaphysis of the left proximal tibia. The entity of intraosseous neurofibroma is briefly reviewed.
The association between congenital pseudoarthrosis and osteofibrous dysplasia of the tibia and fibula is a rare entity that has been recently recognized. We report a male newborn who was found to have swelling and deformity of the left lower leg. Radiographs and magnetic resonance imaging showed an extensive destructive lesion of the tibial shaft, with dysplastic congenital pseudoarthrosis of the lower fibula. Histopathological examination confirmed the diagnosis of congenital pseudoarthrosis of the tibia and fibula with underlying osteofibrous dysplasia involving both bones. Immunohistochemical stains showed cytokeratin positivity.
Radiographic, computed tomographic and scintigraphic findings of a patient with separated, multilocular periosteal ganglion are reported. Multiple periosteal cystic masses with calcification in small parts of the cyst walls were demonstrated in the surface of the left tibia by plain radiograms and CT. The accumulations of technetium-99m hydroxymethylene diphosphonate and pentavalent technetium-99m dimercaptosuccinic acid were shown in the calcification in the periosteum and wall of the cyst. Needle puncture revealed that the masses were filled with jelly-like fluid. The masses were diagnosed as multiple ganglionic cysts at the periosteum of the left tibia.
We used Magnetic resonance imaging (MRI) in five patients (six knees), mean age 13.2 (12-15) years, with late-onset tibia vara (Blount's disease), to study the growth plate and its abnormalities. The MRI study was classified for severity of disease and compared with a radiographic classification. In severely involved knees, MRI indicated severe growth-plate changes on both sides of the knee joint. Widening in the entire proximal tibial growth plate, involvement of the distal femoral growth plate, as well as cartilage invaginations into the metaphyses, were constant findings. Three knees were treated operatively with oblique tibial osteotomy and three with lateral hemiepiphysiodesis. Two severely involved patients treated initially with hemiepiphysiodesis required additional surgery. The three patients with mild disease treated with tibial osteotomy had good clinical and functional results. This study suggests that extensive growth-plate changes in severe, late-onset tibia vara preclude successful treatment by tibial hemiepiphysiodesis. In addition, oblique osteotomy, which was successful in mild cases, was problematic in severe cases.
We analysed 20 patients with 24 knees affected by idiopathic genu recurvatum who were treated with an anterior opening wedge osteotomy of the proximal tibia because of anterior knee pain. We managed to attain full satisfaction in 83% of the patients with a mean follow-up of 7.4 years. The mean Hospital for Special Surgery score was 90.3 (range 70.5-99.5), and the mean Knee Society score score was 94.6 (70-100) for function and 87.7 (47-100) for pain. The mean Western Ontario and McMaster University Osteoarthritis Index score for knee function was 87.5 (42-100), for stiffness 82.8 (25-100) and for pain 87.3 (55-100). Radiographs showed a significant increase in posterior tibial slope of 9.4 deg and a significant decrease of patellar height according to the Blackburne-Peel method of 0.16 postoperatively. No cases of non-union, deep infection or compartment syndrome were seen. No osteoarthritic changes in the lateral or medial knee compartment were found with more than 5 years' follow-up in 16 patients with 19 affected knees. Three out of the four dissatisfied patients had a patella infera which led to patellofemoral complaints. One patient in the study underwent a secondary superior displacement of the patella with excellent results. We conclude that in a selected group of patients with idiopathic genu recurvatum and anterior knee pain an opening wedge osteotomy of the proximal tibia can be beneficial.
A 12-year-old boy with osteosarcoma in the proximal tibia underwent a successful limb-saving operation with preservation of the epiphyseal and articular cartilage of the proximal tibia as a result of his remarkable response to chemotherapy. There was no evidence of tumour invasion to the adjacent physis, as demonstrated by image findings. The bone defect was reconstructed using autoclaved autogeneous bone with a vascularized fibula. The patient exhibits excellent function of the affected limb, and the knee joint remains disease-free 55 months postoperatively.
Primitive malignant neoplasms affecting the distal third of the tibia are altogether rare, and their treatment is considerably controversial. The authors describe the diagnostic procedure and a particular surgical strategy of limb salvage in a case of malignant fibrous histiocytoma located at the distal third of the tibia, in particular pointing out the difficulties in restoring the continuity of the skeletal tissues and of the muscle, and with a review of the relevant literature.
A 23-year-old, male patient previously operated on four times for a recurring, benign, paranasal mass was admitted to our clinic with pain and swelling under the knee. Physical and radiological examination revealed a malignant process. The histopathological examination of the fine-needle biopsy specimen of the tibia was a malignant mixed tumor. Then. en-bloc resection, free fibular grafting, and fixation with blade plate was performed for one-third of the tibia, conserving the knee joint. Recurrences and metastasis were not observed after surgery and radiotherapy.
Cortical bone responses following administration of parathyroid hormone (PTH) were evaluated using a four-point bending device to clarify the relationship between the effect of PTH and mechanical loading. Female Wistar rats, 6-months-old, [corrected] were used. Rats were randomized into three groups (n = 10/group), namely PTH-5 (5 microgram PTH/kg body weight), PTH-30 (30 microgram PTH/kg body weight), and PTH-v (vehicle). PTH (human PTH (1-34)) was injected subcutaneously three times/week for 3 weeks. Loads on the right tibia were applied in vivo at 29.1 +/- 0.3 N for 36 cycles at 2 Hz 3 days/week for 3 weeks using four-point bending. The administration of PTH and tibial mechanical loading were performed on the same day. After calcein double labeling, rats were killed and tibial cross-sections were prepared from the region with maximal bending at the central diaphysis. Histomorphometry was performed over the entire periosteal and endocortical surfaces of the tibiae, dividing the periosteum into lateral and medial surfaces. The in vivo average peak tibial strains (predicted) on the lateral periosteal surface were 1392.4, 1421.8 and 1384.7 (mu)strain in PTH-v, PTH-5 and PTH-30 groups, respectively, showing no significant difference among the three groups. Significant loading-related increases in the bone formation surface, mineral apposition rate, and bone formation rate were observed at the periosteal and endocortical surfaces. Significant differences between PTH groups were also seen. Interaction between mechanical loading and PTH was significant at both periosteal and endocortical surfaces. It is concluded that PTH has a synergistic effect on the cortical bone response to mechanical loading.
Bone changes in both actively growing (6-week-old) and mature (6-month-old) rats with collagen-induced arthritis (CIA) were investigated in order to clarify the mechanisms of osteoporosis near inflamed joints in patients with early rheumatoid arthritis (RA) and juvenile RA. In female Sprague-Dawley rats, the proximal tibiae from the CIA and control groups early after immunization, when any influence of immobilization due to joint pain and swelling is minimal, were studied using dual X-ray absorptiometry and histomorphometry after double-labeling with tetracycline. Arthritis developed within 10-14 days after immunization in both growing and mature rats. Physical activity, growth, and body weight continued to resemble that of the control group for at least 10 days. The bone mineral density in the proximal tibia did not differ significantly between the CIA and control groups. In growing rats, a highly significant increase in bone resorption, and decreases in bone formation and trabecular bone volume became evident histomorphometrically before visible signs of arthritis had developed. In mature rats, bone formation was markedly decreased without an increase in bone resorption. The differences in the reaction between growing and mature rats reflected a difference in the number of remodeling sites (units) and an uncoupling between osteoblasts and osteoclasts. We conclude that osteoporosis near inflamed joints results from an imbalance between bone resorption and formation caused by immune reactions in the CIA rats. Moreover, a decrease in bone formation may, in part, precede the clinical onset of arthritis.
Reconstruction of the knee joint for osteosarcoma of the proximal tibia is a formidable challenge. Here we present two patients whose knees were reconstructed with autologous grafts of whole-knee joint treated by extracorporeal pasteurization. Incorporation at the junction between host and pasteurized bone was evident. On the other hand, direct reattachment of the patellar tendon to the pasteurized tibia was not successful in case 1. In case 2, in contrast, the patella was divided followed by successful reconstruction at the osseous site. Avoiding reattachment of pasteurized ligamentous structure is recommended. The operation protocol is not ideal but so far may be superior to other reconstruction procedures because there are many fundamental complications such as low long-term survival of a massive prosthesis and the lethal risk of transfection (e.g. human immunodeficiency virus); moreover, immunological responses of the allograft can be avoided.
The pathogenesis of bone metastases may require the activation of osteoclasts by tumor-secreted factors, which promote important interactions with the bone microenvironment. We utilized an intratibial model of bone metastasis with bioluminescent imaging (BLI) to measure the effect of osteoclast inhibition on the interaction of human lung cancer cells with bone, and on tumor growth. Mice were injected with luciferase-transduced tumor cells (HARA, human pulmonary squamous carcinoma) and divided into three groups: (1) untreated, (2) twice weekly treatment with the bisphosphonate zoledronic acid (ZOL), or (3) osteoprotegerin (OPG). Histomorphometry and imaging were used to evaluate tumor burden, and parameters of osteoclast activity. Mice in the treated groups had increased bone density and decreased osteoclast numbers in nontumor-bearing tibiae. There was greater than 60% reduction in mean tumor volume in both treatment groups when evaluated by histomorphometry (P = 0.06 [OPG], P = 0.07 [ZOL]). However, bioluminescent imaging failed to show a reduction in tumor burden due to wide variability in the data. Osteoclast numbers along tumor-associated bone were significantly increased compared to tumor-free bone, and were not reduced by either treatment. Plasma calcium concentration was increased in all groups. Plasma tartrate-resistant acid phosphatase 5b was reduced in both treatment groups. Plasma PTHrP was significantly increased in the untreated tumor-bearing group, but was not significantly different in the two treatment groups compared to normal mice. OPG or ZOL did not change tumor cell proliferation, but ZOL increased HARA cell apoptosis. OPG and ZOL reduced tumor growth in the tibiae of treated mice, however, PTHrP production by HARA cells may have resulted in a high concentration in the bone microenvironment, partially overriding the antiosteoclast effects of both OPG and ZOL.
Forskolin (FSK), an activator of adenylate cyclase in many tissues, was investigated to determine its potential for studying cyclic AMP-mediated, physiological events in bone. Tibiae from 14-day chick embryos were cultured in modified Eagle's medium for up to 8 hr, and the cyclic AMP and Ca2+ efflux responses to parathyroid hormone (PTH) and FSK were observed. FSK caused a concentration-related increase in tissue cyclic AMP, with 10(-6) M FSK producing a cyclic AMP response of similar magnitude to that elicited by 10(-6) M PTH (1-34). However, while 10(-6) M PTH was the maximally-activating PTH concentration, a further elevation was produced by 10(-5) M FSK. Chick embryo tibiae cultured for 8 hr in the presence of PTH exhibited a concentration-related stimulation of Ca2+ efflux up to 10(-6) M PTH. When this physiological effect was examined in bones cultured in the presence of FSK, a biphasic response to increasing FSK concentrations was found; Ca2+ efflux was stimulated by 10(-6) M and 3 X 10(-6) M FSK, but not by 10(-7) M or 10(-5) M FSK. In summary, concentrations of FSK, which produced tissue cyclic AMP accumulation similar to that produced by physiologically effective PTH concentrations, also resulted in net Ca2+ efflux from bone. These results indicate that FSK may be a useful agent for studying the role of cyclic AMP in the response of bone to hormones.
Osteogenesis in the embryonic long bone rudiment occurs initially within an outer periosteal membrane and subsequently inside the cartilaginous core as a consequence of the endochondral ossification process. In order to investigate the development of these two different mechanisms of bone formation, embryonic chick tibial cell isolates were prepared from sites of first periosteal bone formation and from the immediately underlying hypertrophic cartilaginous core region. Mid-diaphyseal periosteal collars and the corresponding cartilage core were microdissected free from Hamburger-Hamilton stage 35 (Day 9) chick tibias and separately digested with a trypsin-collagenase enzyme mixture. The released cell populations were cultivated in vitro and characterized by morphological analysis, histochemical localization of alkaline phosphatase, alizarin red S staining for mineral deposition, growth rate [( 3H]thymidine uptake), and proteoglycan content. Results of these studies showed that periosteal collar cell cultures form nodule-like structures that stain positive with alkaline phosphatase and alizarin red S. Light and electron microscopic observation revealed cell and matrix morphologies similar to that of intact periosteum. The nodules were composed of plump cell types embedded within a mineralized matrix surrounded by a fibroblastic cell layer. Core cartilage cell cultures displayed typical characteristics of the hypertrophic state in their visual appearance and proteoglycan composition. The formation of osseous-like structures in periosteal collar cell cultures but not in core chondrocyte cell cultures demonstrates the relatively autonomous nature of intramembranous ossification while emphasizing the dependence of the endochondral ossification process upon an intact vascularized environment present in the developing tibia.
The therapeutic implications of the physical aspects of fractures have not yet been clearly defined. We have studied the fracture characteristics of the tibia of mature male rabbits by producing fractures manually and mechanically. The fractures were studied by radiology, by recording fracture strains graphically and by direct measurement of the magnitude of the fracture force. The fracture behaviour of the mature rabbit tibia was found to be similar to that of adult human bone in that they were brittle and fractured in the tension mode without plastic deformation. Angulatory forces were observed to produce transverse and oblique fractures and spiral forces produced spiral fractures in all cases. The maximum bending moment before fracture was 4000 Nmm, the maximum shear moment was 1870 Nmm and the mean of the maximum tensile stress in each case was 20 N/mm2. It was concluded from this that fractures produced by angulatory forces caused the greater damage to the surrounding soft tissues compared with spiral fractures.
Many studies have been conducted to determine the biomechanical properties of the anterior cruciate ligament (ACL). The method of holding the femur-ACL-tibia complex (FATC) test specimen, the strain rate applied, the angle of knee flexion and the direction of the applied loads have an important effect on the outcome. It is felt that the tensile properties and strength of the ligament should be measured by applying the tensile force along the axis of the ligament. A versatile clamp was designed to accomplish this purpose. Fifty-seven rabbit knee specimens were tested at angles of flexion of 0 degrees, 30 degrees or 90 degrees. In addition, a comparative study of 25 pairs of rabbit legs were performed, whereby loading was either along the ligament or along the tibial axis. Cyclic hysteresis, ultimate load, energy absorbed, and stiffness were determined. The ultimate load values for the FATC decreased with increased knee flexion for those loaded along the tibial axis, while no such change was detected for FATC tested along the ligament axis. Other structural properties measured followed similar trends. It is concluded that the structural properties of the rabbit FATC change minimally with knee flexion (from 0 to 90 degrees) when loaded along the ligament axis, but decrease significantly with knee flexion when loaded along the axis of the tibia. Therefore, the data obtained in this field of study can be compared only if the direction of loading with respect to the ACL is similar.
A method is proposed to measure the phase velocities of the first mode of flexural waves in the human tibia. Keeping in mind the dispersive nature of flexural waves in beam-like bodies, a two point measurement method was developed which enables the calculation of the phase difference of the propagating wave between two observation points for a selected frequency range. The method for dispersion analysis was tested with synthetic and observed signals for a cylinder. This was done by comparison of observed radial acceleration on the surface of a PVC-cylinder with computed synthetic signals consisting only of first mode flexural waves. An in vivo study was performed with 43 subjects. The phase velocity measurements in human tibia show a good correlation with the bone mineral content estimated by means of the Cameron-Sorenson technique (Cameron and Sorenson, 1963). The bone mineral loss is reflected by decreasing phase velocities. This indicates that phase velocity measurements of flexural waves can be used for an estimation of bone mineral content in vivo.
The anatomical variation of orthotropic elastic moduli of the cancellous bone from three human proximal tibiae was investigated using an ultrasonic technique. With this technique, it was possible to measure three orthogonal elastic moduli and three shear moduli from cubic specimens of cancellous bone as small as 8 mm per side. Correlation with mechanical tensile testing has shown this technique to offer a precise measure of cancellous modulus (Eten = 0.94Eult + 144.6 MPa, r2 = 0.96, n = 34). The cancellous bone of the proximal tibia was found to be very inhomogeneous, with the axial modulus ranging between 340 and 3350 MPa. A course map is presented, showing measured Young's moduli as a function of anatomical position. The anisotropy of the cancellous bone, determined by the relative differences between the three orthogonal moduli, was shown to be relatively constant over the entire range of cancellous densities tested. The relationship between the axial elastic modulus and the apparent density was found to be approximately linear, as reported by others for proximal tibial cancellous bone.