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This study examines the use of a devitalized biological knee as a scaffold for repopulation with chondrocytes and tests the hypothesis that the devitalized scaffold would become repopulated with the foreign chondrocytes when placed in a suitable environment. Chimeric knee constructs were engineered in vitro and their ectopic in vivo fate was examined in SCID mice. The constructs were made by applying porous collagen sponges that contained viable bovine articular chondrocytes to shaved articular surfaces of devitalized embryonic chick knees. The chimeric joints were cultured for 1 week and were subsequently transplanted into dorsal subcutaneous pouches of 5-week-old mice. Specimens were prepared for histological analysis at 1, 3, 6, or 8 weeks after transplantation. Controls included empty collagen sponges, collagen sponges seeded with viable bovine chondrocytes, and devitalized chick knees without collagen sponge inserts. One week after in vitro incubation of the constructs, the porous collagen sponges with viable bovine chondrocytes were adherent to the shaved articular surfaces of the devitalized chick joints. There was abundant metachromatic neomatrix around the chondrocytes in the collagen sponges. During maintenance of the constructs in vivo, the chimeric joints exhibited dramatic changes. Bovine chondrocytes proliferated in the collagen sponges and formed abundant new matrix. Bovine chondrocytes migrated into preexisting chick cartilage canals at 1 week. Subsequently, bovine chondrocytes invaded the matrix of the devitalized chick knees. Bovine neocartilage obliterated the interface between the collagen sponge and the devitalized chick cartilage. With time in vivo, the bovine neocartilage expanded and replaced the chick matrix. The devitalized cartilage appears to provide a framework for supporting chondrogenesis in a chimeric joint.

Background: The avascular portion of the meniscus cartilage in the knee does not have the ability to repair spontaneously., Hypothesis: Cell-based therapy is able to repair a lesion in the swine meniscus., Study Design: Controlled laboratory study., Methods: Sixteen Yorkshire pigs were divided into four groups. A longitudinal tear was produced in the avascular portion of the left medial meniscus of 4 pigs. Autologous chondrocytes were seeded onto devitalized allogenic meniscal slices and were secured inside the lesion with two sutures. Identical incisions were created in 12 other pigs, which were used as three separate control groups: 4 animals treated with an unseeded scaffold, 4 were simply sutured, and 4 were left untreated. Meniscal samples were collected after 9 weeks, and the samples were analyzed grossly, histologically, and histomorphometrically., Results: Gross results showed bonding of the lesion margins in the specimens of the experimental group, whereas no repair was noted in any of the control group specimens. Histological and histomorphometrical analysis showed multiple areas of healing in the specimens of the experimental group., Conclusions: This study demonstrated the ability of seeded chondrocytes to heal a meniscal tear., Clinical Relevance: Cell-based therapy could be a potential tool for avascular meniscus repair.

Chondroblastomas are benign cartilaginous lesions; however, intervention is necessary to stop progression and alleviate pain. The authors evaluated three patients in whom minimally invasive percutaneous radio-frequency heat ablation was used to treat pathologically proven chondroblastoma to determine whether this treatment demonstrated long-term success. The authors found that this approach may be an effective alternative to surgical intervention in some cases.

In this study, devitalized meniscal tissue pre-seeded with viable cultured chondrocytes was used to repair a bucket-handle incision in meniscal tissue transplanted to nude mice. Lamb knee menisci were devitalized by cyclic freezing and thawing. Chips measuring four by two by one-half millimeters were cut from this devitalized tissue to serve as scaffolds. These chips were then cultured either with or without viable allogeneic lamb chondrocytes. From the inner third of the devitalized meniscal tissue, rectangles were also cut approximately 8 x 6 mm. A 4 mm bucket-handle type incision was made in these blocks. The previously prepared chips either with (experimental group) or without viable chondrocytes (control group) were positioned into the incisions and secured with suture. Further control groups included blocks of devitalized menisci with incisions into which no chips were positioned and either closed with suture or left open with no suture. Specimens were transplanted to subcutaneous pouches of nude mice for 14 weeks. After 14 weeks, seven of eight experimental specimens (chips with viable chondrocytes) demonstrated bridging of the incision assessed by gross inspection and manual distraction. All the control groups were markedly different from the experimental group in that the incision remained grossly visible. Histological analysis was consistent with the differences apparent at the gross level. Only the experimental specimens (chips with viable chondrocytes) with gross bridging demonstrated obliteration of the interface between incision and scaffold. None of the control specimens revealed any cells or tissue filling the incision. Tissue engineering using scaffolds and viable cells may have an application in meniscal repair in vivo.

The objective of this study was to evaluate the biomechanical properties of newly formed cartilaginous tissue synthesized from isolated chondrocytes. Cartilage from articular joints of lambs was either digested in collagenase to isolated chondrocytes or cut into discs that were devitalized by multiple freeze-thaw cycles. Isolated cells were incubated in suspension culture in the presence of devitalized cartilage matrix for 3 weeks. Multiple chondrocyte/matrix constructs were assembled with fibrin glue and implanted subcutaneously in nude mice for up to 6 weeks. Testing methods were devised to quantify integration of cartilage pieces and mechanical properties of constructs. These studies showed monotonic increase with time in tensile strength, fracture strain, fracture energy, and tensile modulus to values 5-10% of normal articular cartilage by 6 weeks in vivo. Histological analysis indicated that chondrocytes grown on dead cartilage matrix produced new matrix that integrated individual cartilage pieces with mechanically functional tissue.

More than 50 surgical procedures have been described for treatment of chronic lateral ankle instability. Anatomic repairs have come into favor in the recent literature based on short-term studies, which have used objective measures for outcome. A long-term (range, 7-20 years; average, 12.6) patient-oriented outcome analysis was performed on 20 patients that underwent a modified Evans procedure for chronic lateral ankle instability by the senior author over a 13-year period. There was a 91% follow-up on all located patients (20 of 22). All patients had mechanical and functional instability, and all had failed conservative therapy. A questionnaire, based on the outcomes questionnaire developed by the American Academy of Orthopaedic Surgeons was used to determine functional stability. The patient's ability to perform recreational or competitive sporting activities at specific time intervals were also assessed (preinjury, 1 year postoperatively, present time). Overall result was considered satisfactory if five criteria were met: patents (a) were happy with the outcome of surgery, (b) were able to perform desired level of activities, (c) had functional stability, (d) were pain free performing desired level activities, (e) would undergo procedure again. The entire cohort demonstrated satisfactory results in 19 (95%) of 20 respondents at 1 year and 17 (85%) at present time. Grouping patients into competitive (12 cases) and recreational (eight cases) athletes demonstrated six of 12, and seven of eight reached their preinjury level (p = 0.074). In this study, we showed that surgical reconstruction using a modified Evans procedure is a reliable and effective treatment for chronic lateral instability. This procedure has proved to stand the test of time, as demonstrated by a patient-oriented outcome analysis. The elite athlete may be better served by a procedure using the principles of anatomic rather than augmented repair; however, the long-term data to our knowledge has yet to be published.

The clinical response of growth plate to exogenous forces is well recognized, although the organ-level mechanisms are poorly understood. Physeal cartilage from 5- to 7-day-old bovine distal radii was subjected to 245 N of tension or 245 N of compression (0.012 MPa) in organ culture over a 24-h period. Eleven specimens (six tension, five compression) were assayed for cellular proliferation with tritiated thymidine. Eighteen specimens (12 tension, six compression) were assayed for synthetic activity with radioactive sulfate. Media were assayed for prostaglandin production. Tension increased whereas compression decreased synthetic activity and prostaglandin production by physeal cartilage in explant culture over a 24-h period. There was no significant change in thymidine uptake. Physeal cartilage can respond to both tension and compression and, in the short term, appears to alter synthetic activity without changing the rate of cell proliferation. This study system allows local sampling and manipulation of the physeal organ environment and may lead to ways of approaching growth-plate pathologies in vivo.

A number of proteins have recently been identified which play roles in regulating bone development. One important example is Indian hedgehog (Ihh) which is secreted by the prehyprtrophic chondrocytes. Ihh acts as an activator of a second secreted factor, parathyroid hormone-related protein (PTHrP), which, in turn, negatively regulates the rate of chondrocyte differentiation. Here we examine the expression of these genes and their molecular targets during different stages of bone development. In addition to regulating PTHrP expression in the perichondrium, we find evidence that Ihh may also act on the chondrocytes themselves at particular stages. As bone growth continues postnatally in mammals and the developmental process is reactivated during fracture repair, understanding the molecular basis regulating bone development is of medical relevance. We find that the same molecules that regulate embryonic endochondral ossification are also expressed during postnatal bone growth and fracture healing, suggesting that these processes are controlled by similar mechanisms.

The capacity of isolated chondrocytes to join separate masses of cartilage matrix was investigated with composites implanted in subcutaneous pouches in nude mice. Slices of articular cartilage were harvested from lambs and were devitalized by cyclic freezing and thawing. The slices were then either co-cultured with viable allogeneic lamb chondrocytes (experimental) or cultured without such chondrocytes (control). Composites of three slices were constructed with use of fibrin glue and were implanted in nude mice for periods ranging from 7 to 42 days. Bonding of the experimental matrices with viable chondrocytes was achieved at 28 and 42 days, as assessed by direct examination, histology, thymidine uptake, and fluorescence. No bonding occurred in the control composites without viable chondrocytes. We conclude that devitalized cartilage matrix is a scaffold to which isolated chondrocytes can attach and begin to repopulate.

In a multicenter study of pediatric lawn-mower injuries (push or riding gas-powered machines), we reviewed 144 children at an average age of injury of 7.0 years; 77% were boys. Most injuries (92 of 104) occurred in the afternoon. The child was the machine operator in 36 cases, a bystander in 84, and a passenger in 21. The average hospital stay was 13.3 days with 2.6 surgeries per child. Amputations occurred in 67 children; 63 were unilateral and four bilateral; the most common level was the toes (63%). Blood transfusions were given to 35 children. Children injured by riding lawn mowers, when compared with those by push lawn mowers, were younger (5.4 vs. 11.0 years), less frequently the operator (15 vs. 60%), had longer hospitalizations (15.0 vs. 8.9 days), and required more surgeries (3.0 vs. 1.6) and blood transfusions (41 vs. 3%). Children with free flaps needed more transfusions (78 vs. 26%), and transfused children were younger (4.6 vs. 8.1 years), more likely to be bystanders (91 vs. 63%), required more surgeries (4.1 vs. 2.0), and were hospitalized longer (21.6 vs. 9.7 days). Soft-tissue infections occurred in eight of 118 and osteomyelitis occurred in six of 117 children. At an average follow-up of 1.9 years, there were 43 satisfactory and 84 unsatisfactory results. When excluding those children with amputations of digits, there were 42 satisfactory and 47 unsatisfactory results. If children younger than 14 years had not been permitted around lawn mowers, approximately 85% of the injuries in this report would have been prevented. Further public dissemination of the following information is needed: (a) children younger than 14 years should not operate lawn mowers, (b) children younger than 14 years should not be in the yard while the lawn is being mowed, and (c) no passengers, regardless of age, should be allowed on riding mowers.

Growth of chondrocytes into a xenogeneic chondroepiphyseal matrix was investigated in an in vitro experimental model by combining viable calf chondrocytes with chick epiphyseal matrix devoid of viable chondrocytes. The chondrocytes were harvested from the wrist joints of newborn calves and cultured for 2 days. The epiphyses were harvested from the distal femurs and the proximal tibias of fetal chicks after development was arrested at 17 days by freezing. The epiphyseal specimens were prepared in four ways. These included femoral and tibial epiphyses without holes and femoral and tibial epiphyses with holes made by a laser. These epiphyseal specimens were co-cultured with calf chondrocytes for various periods. After digestion of the epiphyseal matrix, viable chondrocytes were counted in suspension. Chondrocyte division in the matrix was assessed by [3H]thymidine incorporation. The growth of calf chondrocytes into the xenogeneic chick matrix was evaluated by fluorescence microscopy on fresh thick epiphyseal sections. The percentage of viable chondrocytes in the xenogeneic epiphyseal matrix increased with culture time to a maximum at day 21. The addition of laser-drilled holes was found to extend a plateau of chondrocyte viability until day 29. A decrease in cell viability was detected at later observation points. This study demonstrates that xenogeneic matrix may serve as a morphogenetic scaffold for chondrocytic growth.

Caffey's disease is a cortical hyperostosis, which presents during infancy. Etiology remains unclear. Familial occurrence has been documented in the literature. Reported here is infantile cortical hyperostosis that occurred in a father and his two daughters. The familial occurrence would suggest a genetic basis for Caffey's disease; however, it remains consistent with infection by an agent with a long latency period as has been strongly suggested in Paget's disease.

Epiphyseal replacement was performed via knee transplantation using donor tissue of different developmental times in a murine model. The performance of syngeneic donor tissue in a resection defect in 4-day-old mice of the same inbred strain was assessed over 2 weeks for cell viability, tritiated thymidine incorporation, and ability to attract a host blood supply, and at 2 months, with the existence of a joint and growth. Although there was variability within experimental groups, the syngeneic transplant was able to survive pending vascular invasion from the host. Growth occurred, although it never equaled normal growth. One possible approach to the difficult problem of joint reconstruction in the immature skeleton is to divide the endeavor into two parts: develop models of syngeneic joint transplantation in inbred strains of animals to assess the various problems that would occur were this tissue available and develop models of joint "synthesis" with autogeneic chondrocytes.

Abnormalities of the growth plate secondary to epiphyseal and metaphyseal injury were studied with magnetic resonance (MR) imaging, radiography, and histologic examination in 20 rabbits. Epiphyseal injury resulted in either the formation of a bony bridge across the growth plate or focal curving of the growth plate caused by a decrease in longitudinal growth. Metaphyseal injury resulted in interference with endochondral ossification, thickening of the growth plate, and extension of cartilage into the metaphysis. Serial MR images obtained during the first 6 weeks after injury showed persistence of abnormalities of the growth cartilage after epiphyseal injury, but resolution of abnormalities after metaphyseal injury. Abnormalities of the cartilage were best seen on T2-weighted images. Gadolinium enhancement showed reconstitution of metaphyseal vascularity after metaphyseal injury but did not enable detection of transphyseal vascularity after epiphyseal injury until a bony bridge formed.

Reconstruction of physeal regions excised from the distal femoral chondroepiphysis was attempted in a murine model. Cultured chondrocytes of varying developmental time from the same inbred strain of mice were used for replacement. Vascularity, matrix formation, and cell division, as well as growth, were assessed. The cultured chondrocytes did not produce growth. Consistent with this, cell division, as assessed with incorporation of tritiated thymidine, was not normal. However, the cultured chondrocytes did receive a nutritional supply from the host and did continue matrix formation after transplantation.

Reconstruction of physeal regions excised from the distal femoral chondroepiphysis was performed in a murine model. The excised regions were replaced with analogous blocks of syngeneic tissue. Vascularity, matrix formation, and cell division were assessed as well as growth. The blocks of tissue did not produce growth consistently, although individual specimens did show some growth. Tritiated thymidine incorporation by the proliferative zone of the transplanted block of tissue was not normal. The blocks of tissue did receive a nutritional supply from the host and did continue matrix formation after transplantation.

We studied a model of pin protrusion in rabbit hips to determine if chondrolysis is produced. Enzymatic degradation of the articular cartilage remote from the pin site and mechanical destruction of the acetabulum occurred. Loss of proteoglycans in the articular cartilage averaged approximately 30%, and matched the increase in neutral protease activity. This presumably accounts for the loss of height that occurs in chondrolysis, but throughout the study, the joint space did not narrow; instead, it increased. This suggests that some other factor is needed to produce chondrolysis, such as a slip or an immune response.

The effects of chondrodiatasis on chondrocyte division, matrix synthesis, and microcirculation in rabbit growth plate were studied. The procedure did not produce any significant change in the percentage of cells labeled with tritiated thymidine, the intensity of radioactive sulfate labeling of the matrix, or the blood supply of the physis. These findings suggest that the procedure does not work by stimulating cell division, synthetic function, or vascularity of the plate, but rather by stretching the matrix passively.

Hypointense epiphyseal marrow on T1-weighted magnetic resonance images often suggests disease. To determine whether hypointense marrow sometimes represents normal red marrow in a recently ossified epiphyseal center, the authors studied 38 infants without known marrow disease. Patients with hypointense epiphyseal marrow on T1-weighted images were younger (3.9 months +/- 3.2) than those with hyperintense marrow (9.6 months +/- 3.9) (P less than .001). T1-weighted imaging and histologic correlation were also performed in animals. The signal was hypointense and the marrow was red in the epiphyseal centers of all newborn animals, while all 6-week-old animals had hyperintense signal and yellow marrow. The authors conclude that hypointense marrow on T1-weighted images represents normal red marrow in a recently formed ossification center in newborn rabbits and lambs, and the same is probably true in humans. Epiphyseal marrow becomes hyperintense within a few months of development of the secondary center of ossification.

Physeal reconstruction was performed in a murine model by transplanting corresponding postnatal tissue from 4-day-old C57B mice to resection defects. The site of the reconstruction, the murine distal femoral epiphysis, is completely cartilaginous and avascular at this stage of development. The tissue transplanted into the defect was demonstrated to have high kinetic activity by its incorporation of tritiated thymidine. The physeal reconstruction as performed restored only 25% of normal growth. While transplanting cell populations is feasible, the method will require a great deal of work before clinical application.

Epiphyseal reconstruction in the immature skeleton could have great clinical significance. Hemiepiphyseal reconstruction was performed in a murine model by transplanting fetal tissue to surgically created defects in postnatal mice. Reconstruction is facilitated by the existence of inbred strains. While the reconstruction as performed here did not completely restore the growth characteristics of the epiphysis, the model represents a potentially fruitful interface between basic and clinical biology.

Longitudinal bone growth is the ultimate characteristic clinically desired from the physis. Measuring relatively short-term parameters in comparison with growth may help facilitate investigation of physeal reconstruction. We monitored the viability and metabolism of cartilage transplanted to physeal regions in rabbits. In addition to measuring growth, we performed histochemistry and autoradiographic studies. The results indicated that cartilage transplanted in an avascular fashion could remain viable, synthesize proteoglycan, and be associated with growth (although less than normal) relative to controls. Such measurements may be of benefit in pursuing the goal of clinical physeal reconstruction.

Eighteen cases of Sprengel deformity in sixteen patients were treated by the same surgeon. The operation was a modification of Green's procedure; all muscular attachments to the scapula are freed, the omovertebral band is cut, and the scapula is sutured into a pocket in the latissimus dorsi after the scapula has been rotated and moved caudad to a more normal position. No spring or wire traction is employed. The ages of the patients at operation ranged from twenty months to five years and ten months. The duration of follow-up ranged from three years to fourteen years and three months. In eleven of the fifteen patients who were available for follow-up, there was a moderate or dramatic improvement in appearance postoperatively. Preoperatively, the total abduction of the shoulder averaged 91 degrees (range, 60 to 120 degrees), and postoperatively, the abduction averaged 148 degrees. A radiographic geometric method was devised to quantitate lowering and derotation of the scapula. The lowering did not change appreciably with time. The original malrotation of the scapula was corrected initially but usually recurred after two years; however, this did not compromise the large increase in abduction postoperatively.

The advances of developmental biology are beginning to unravel the mechanisms behind congenital anomalies and should, in the not too distant future, have an impact upon their treatment. Much of classic developmental biology represents careful descriptions of the developing body form, in this case the upper limb. There is a great deal to be learned from this approach. More recent experimental manipulations of limb development are serving to establish the basic processes by which form is generated in each cycle of life. Such experimental manipulations might also be regarded as potential prototypes for surgical interventions of the future.

The stereochemical constraints originally used to construct two- and three-stranded alpha-helical coiled-coils were generalized for aggregates of alpha-helices containing from 4 to 14 alpha-helices in tubular bundles. Certain features of bacteriorhodopsin show excellent correlations with these stereochemical constraints.

The purpose of this study was to see if kinetic and biochemical heterogeneity could be documented in vertebrate chondroepiphyseal regions as they develop from mesenchymal condensations to cartilage. The kinetics of developing proximal and distal femoral chondroepiphyseal regions were studied from early limb bud stage to newborn animals in chicks, mice, and rabbits with thymidine autoradiography. Proteoglycan synthesis in the proximal femoral chondroepiphyseal region of the rabbit was studied with radioactive sulfate incorporation at 28 days of gestation and at 1 and 4 days after birth. The results indicated that these kinetic and biochemical characteristics of the developing chondroepiphyseal regions became heterogeneous very early in development. This early programming of populations of cells for division and for different biochemical functions existed during the fetal period when heterogeneity has been described histologically but has not been well documented.

This report documents the clinical testing of scanning beam digital radiography as an imaging method in patients with scoliosis. This type of digital imaging requires a skin exposure of only 2.4 mR (0.619 microC/kg) per image, compared with the lowest possible posteroanterior screen-film exposure of 10 mR (2.58 microC/kg) at the chest and 60 mR (15.48 microC/kg) at the lumbar spine. Digital radiographic and screen-film images were obtained on multiple test objects and 273 patients. Scoliosis measurements using screen-film radiographs and digital radiographs were comparable to within a mean difference of 1 degrees at many different degrees of severity. The low-dose digital images were found to be useful and accurate for the detection and measurement of scoliosis after the first screen-film radiographs have excluded tumors and structural abnormalities.

Because of the information it provides, computerized tomography has gained wide acceptance. However, the radiation delivered is considerable, and the gonads cannot be shielded effectively. Transaxial tomography also produces a cross-sectional image. While the image has less resolution, it is obtained at a fraction of the exposure. The use of transaxial tomography in several clinical situations is outlined here.

Low-dose transaxial tomography is a technique that can produce cross-sectional images of the hips and femurs in children to permit calculation of the angle of femoral anteversion. Transaxial tomography was compared with computed tomography in terms of measured radiation dose and image quality. Transaxial tomography was found to require at least 90% less radiation dose, and the images were judged to be acceptable for the determination of anteversion.

Although the formation of a secondary center of ossification is often compared with that of the primary center, there are striking differences between these processes. In the formation of the primary center, vascular invasion is always associated with the maturation of chondrocytes, whereas vascularization of the epiphysis can proceed in two different ways. In some species, the epiphysis is vascularized by cartilage canals before the appearance of the secondary center. However, in the mouse, the distal femoral epiphysis is vascularized by peripheral vascular invasion without pre-existing cartilage canals. Histological study of serial sections and studies of vascularization by injection with India ink demonstrated the relationship between hypertrophic chondrocyte formation, vascular invasion, and the formation of the secondary center of ossification in the murine distal femoral epiphysis.

Thirty-eight cases of musculoskeletal pain in a pediatric population that defied diagnosis are reviewed. The time between the onset of symptoms and the final diagnosis averaged 11.4 months, but in many cases was greater than 1 year. The most common diagnoses included reflex sympathetic dystrophy, osteoid osteoma, osteomyelitis, intraarticular hemangiomata, slipped epiphyses, and rheumatoid variants. There were several uncommon causes of pain, such as soft tissue hemangiomata, dystonia, and Addison disease. The pitfalls and causes of error are reviewed.

Epiphyseal transplantation has long been a goal of orthopaedic surgeons. While microvascular surgery has raised hopes that this goal could be achieved, factors other than blood supply also appear capable of affecting the function of the epiphysis. Basic research into the biology of the epiphysis appears to be required. This would be facilitated with a model of epiphyseal transplantation using a small mammal. The purpose of this experiment was to develop such a model in the mouse. Developing CD1 mouse or Lewis rat limb tissue was used to replace knee tissue that had been resected from CD1 postnatal mouse hosts. Donor tissue ranged from 14-day embryonic mouse to 9-day postnatal mouse or 18- and 19-day fetal rat, which has a gestation similar to the mouse. The murine tissue is known to be avascular prior to the sixth postnatal day. The limbs were analyzed radiographically and histologically. The results show that epiphyseal replacement could be studied using developing tissue donors in a murine model. The results suggest that donor tissue prior to vascularization and tissue combinations with the least developmental time mismatch (the least heterochronicity) produced relatively the best, although still abnormal epiphyses.

Poor results with pediatric forearm fractures, while infrequent, do occur. Systematic analysis is required to identify this relatively rare, evolving problem. The purpose of this retrospective study was to identify and organize factors that would help in this process. Sixty-nine patients aged one-17 years with displaced forearm fractures were identified retrospectively. Pre- and postreduction radiographs were analyzed in comparison to standards for displacement, angulation, bow, shortening, and rotation. Those patients who seemed most likely to have problems following treatment were recontacted. Even with the use of stringent criteria in a group weighted toward more severe fractures, 85% of the patients achieved satisfactory results. With careful analysis of fractures for changes in angulation, bow, and disruption of the proximal or distal radioulnar joints, these problems should be avoidable. Analysis relative to standard radiographs aids in the identification of subtle malalignments that would otherwise be easily overlooked.

A retrospective review of 29 patients with surgically treated intraspinal lipomas was conducted in a determination of their manner of presentation and response to treatment. The average age at the time of diagnosis for the entire group was 12.8 years. Only five patients were neurologically normal by clinical examination at the time of diagnosis, and these five patients were all less than 6 months old. Orthopedic intervention was judged successful in each of the 11 foot-procedures done after surgery on the lipoma, but in only two of the five foot procedures done before such surgery. We conclude that consideration of intraspinal lipoma is worthwhile in several circumstances, including pediatric foot deformities.

Although several theories have been advanced about etiology of idiopathic scoliosis, the pathogenesis still remains unknown. One study detected a decrease in the glycosaminoglycan content of the nucleus pulposus in idiopathic scoliosis, and it was theorized that this represented increased degradation. The present study was designed to investigate degradative enzyme activity in scoliotic intervertebral disks. Twenty-three disks from 5 patients with idiopathic scoliosis and 18 disks from 3 patients with scoliosis resulting from myelomeningocele were obtained at surgery (Dwyer procedure). Five disks were obtained during 2 postmortem examinations. Analyses of hydroxyproline, hexosamine and acid phosphatase were performed separately on the annulus and nucleus of each disk. Hexosamine was decreased in idiopathic scoliotic nuclei versus controls (p less than 0.001) by approximately 25%. Hydroxyproline was proportionately increased (p less than 0.05). Similar changes of a greater magnitude were seen when comparing myelomeningoceles to controls. In both types of scoliosis, acid phosphatase was elevated in nuclear and annular tissue. Acid phosphatase activity and hexosamine varied inversely in the nucleus. Finding similar biochemical patterns in idiopathic and neurovascular scoliosis raises the possibility that these changes may be secondary.

To attempt to understand the etiology of failures of chemonucleolysis, biochemical analyses were performed on intervertebral disk material to determine if the enzyme had actually digested the nucleus pulposus proteoglycans. This information was then correlated with the clinical laboratory data to see if a pattern evolved for the failures. Nine chymopapain treated disks, 6 untreated herniated disks and 6 lumbar disks from scoliotic patients were obtained at surgery. The results indicated that 6 out of 9 patients treated with chymopapain had a marked reduction in the proteoglycan (hexosamine) content of their disk compared to the untreated controls. There was a significant inverse correlation of intrinsic lysosomal enzymes and hexosamine content in those cases where the chymopapain failed to destroy the proteoglycan. The other 3 patients, however, had hexosamine levels virtually identical to those disks not treated with chymopapain. The clinical evaluation, consisting of preoperative myelograms, diskograms, the surgeon's observations at laminectomy and evaluation of the postoperative regimen did not explain the failures. This study suggests that the chymopapain failures are not the result of inactivity of the enzyme or failure to digest the nuclear material in at least 6 of the 9 cases. However, there were 3 patients where either the enzyme was not reaching the nuclear material or it was inactive.

We studied the behavior of the distal femoral and proximal tibial physes after whole knee-joint replantation in skeletally immature New Zealand White Rabbits. We developed an operative model in which a rabbit's knee was isolated on a vascular pedicle and was then replanted using microvascular technique. In a short-term study (three weeks or less) of ten rabbits, the patency of the vascular repairs and the resumption of metabolic activity of the cells in the growth plates were assessed. A long-term study (ninety days) of eight rabbits was designed to monitor growth after replantation. The results indicated that in rabbits, the femoral and tibial growth plates could be removed and returned to place during whole-joint replantation. If the blood supply was successfully re-established, metabolic function of the cells in the physes remained normal during the early postoperative period, and at ninety days (near the time of skeletal maturity) bone growth in the limb that was operated on was about equal to that of the opposite limb which was not operated on.

The literature documents progression of spondylolisthesis, most commonly during the adolescent growth spurt. Twenty-eight patients with Grades I and II spondylolisthesis were treated with antilordotic braces. Presenting signs and symptoms included back pain (61%), tight hamstrings (53%), increased lordosis (25%), and mild scoliosis (21%). Three patients presented with spondylolysis and progressed to a slip prior to initiation of brace treatment. Mean duration of brace treatment was 25 months. In the brace, lateral roentgenograms demonstrated a significant reduction of lumbar lordosis and sacral inclination. At the conclusion of brace treatment all patients were pain-free and none had demonstrated a significant increase in slip percent.