Musculoskeletal problems in association with cloacal exstrophy

A long-term outcome (up to 29 years) of bilateral iliac wings "bayonet osteotomies" for closure of bladder exstrophy

BACKGROUND

Several types of pelvic osteotomy techniques have been reported and employed by orthopedic surgeons to enhance the approximation of symphyseal diastasis in bladder exstrophy patients. However, there is limited evidence on a long-term follow-up to confirm which osteotomy techniques provide the most suitable and effective outcomes for correcting pelvic deformities. This study aimed to describe the surgical technique of bilateral iliac bayonet osteotomies for correcting pelvic bone without using fixation in bladder exstrophy and to report on the long-term clinical and radiographic outcomes following the bayonet osteotomies.

METHODS

We retrospectively reviewed patients with bladder exstrophy who underwent bilateral iliac bayonet osteotomies with the closure of bladder exstrophy between 1993 and 2022. Clinical outcomes and radiographic pubic symphyseal diastasis measurements were evaluated. From a total of 28 operated cases, eleven were able to attend a special follow-up clinic or were interviewed by telephone by one of the authors with completed charts and recorded data.

RESULTS

A total of 11 patients (9 female and 2 male) with an average age at operation of 9.14 ± 11.57 months. The average followed-up time was 14.67 ± 9.24 years (0.75-29), with the average modified Harris Hip score being 90.45 ± 1.21. All patients demonstrated decreased pubic symphyseal diastasis distance (2.05 ± 1.13 cm) compared to preoperative (4.58 ± 1.37 cm) without any evidence of nonunion. At the latest follow-up, the average foot progression angle was externally rotated 6.25° ± 4.79° with full hips ROM, and no patients reported abnormal gait, hip pain, limping, or leg length discrepancy.

CONCLUSIONS

Bilateral iliac wings bayonet osteotomies technique demonstrated a safe and successful pubic symphyseal diastasis closure with an improvement both clinically and radiographically. Moreover, it showed good long-term results and excellent patient's reported outcome scores. Therefore, it would be another effective option for pelvic osteotomy in treating bladder exstrophy patients.

Hip Prognosis in Patients With Congenital Diastasis of the Pubic Symphysis

BACKGROUND

Congenital diastasis of the pubic symphysis (CDPS) is a rare musculoskeletal malformation in the exstrophy-epispadias complex that is potentially associated with the development of hip dysplasia. The purpose of this study was to investigate the incidence and prognostic factors of hip dysplasia in patients with CDPS.

METHODS

Fifty-four hips in 27 patients with CDPS initially evaluated between 1983 and 2016 were retrospectively reviewed. The mean age at the first visit was 2.3 (0 to 8) years. The mean follow-up duration was 10.5 (1 to 36) years. Patient characteristics at the first visit, the clinical course at the most recent follow-up, and radiologic parameters on pubic malformation and hip dysplasia during at least 2 time points (first visit or age 1, and either the most recent visit or before hip surgery) were evaluated. Prognostic factors associated with the development of hip dysplasia were analyzed using univariate/multivariate analysis. The Kaplan-Meier survival curves were generated and compared based on these factors.

RESULTS

Nine of 27 patients (33%) and 13 of 54 hip joints (24%) with CDPS developed hip dysplasia. Paraplegia (odds ratio, 10.0; 95% confidence interval, 1.7-76.6) and center-edge angle of <5 degrees at the first visit or age 1 (P<0.001) were independent predictors of the development of hip dysplasia. Patients with CDPS and either paraplegia or center-edge angle <5 degrees at the first visit or age 1 were significantly more likely to develop hip dysplasia than other patients (hazard ratio, 29.3; 95% confidence interval, 3.4-250).

CONCLUSIONS

Approximately one third of patients with CDPS develop hip dysplasia. Paraplegia and center-edge angle of <5 degrees at the first visit are independent risk factors.

LEVEL OF EVIDENCE

Level III.

Towards the control of the biological identity of nanobiomaterials: Impact of the structure of 011¯0 surface terminations of nanohydroxyapatite on the conformation of adsorbed proteins

High-resolution transmission electron microscopy, ζ-potential and in-situ IR spectroscopy of adsorbed CO were combined for elucidating the ratio between {011¯0}_ Ca-rich: {011¯0}_ P-rich terminations of {011¯0} facets, i.e. the surfaces with the highest morphological importance, in two nanohydroxyapatite samples. Bovine serum albumin was found to form at least a monolayer on the surface left accessible to protein molecules by the agglomeration of nanoparticles when suspended in the buffered incubation medium. Noticeably, the conformation of adsorbed proteins appeared sensitive to the ratio between the two types of {011¯0} terminations, also resulting in a difference in the surface exposed toward the exterior by the adsorbed protein layer(s).

Yolk shell nanocomposite particles as bioactive bone fillers and growth factor carriers

The efficient delivery of bioactive molecules via rationally designed nanoparticles is an important focus in regenerative medicine. The yolk shell nanocomposite particles described herein are composed of silk fibroin movable cores formed within voided calcium carbonate shells to load and control the release of labile cytokines. These particles are excellent carrier vehicles of potent molecules as they sustained the release of bioactive Bone Morphogenetic Protein 2 (BMP-2) for more than 28 days in vitro. Implantation into bone defects in rabbits corroborates the in vitro results and also reveals that upon contact with phosphate containing body fluids, implanted yolk shell particles agglomerate and transform into a filler that adapts to defect contour to further act as an absorbable hemostatic agent. Taken together, the fabrication of these yolk shell particle-based "bone fillers" could expand the horizon for the development of newer generations of advanced bioactive materials in tissue regeneration applications.

Minimizing Stress Shielding and Cement Damage in Cemented Femoral Component of a Hip Prosthesis through Computational Design Optimization

The average life expectancy of many people undergoing total hip replacement (THR) exceeds twenty-five years and the demand for implants that increase the load-bearing capability of the bone without affecting the short- or long-term stability of the prosthesis is high. Mechanical failure owing to cement damage and stress shielding of the bone are the main factors affecting the long-term survival of cemented hip prostheses and implant design must realistically adjust to balance between these two conflicting effects. In the following analysis we introduce a novel methodology to achieve this objective, the numerical technique combines automatic and realistic modeling of the implant and embedding medium, and finite element analysis to assess the levels of stress shielding and cement damage and, finally, global optimization, using orthogonal arrays and probabilistic restarts, were used. Applications to implants, fabricated using a homogeneous material and a functionally graded material, were presented.

Incidence of Hip Dysplasia Associated With Bladder Exstrophy

BACKGROUND

Exstrophy of the bladder is a rare congenital defect seen in 2.15 children out of every 100,000 live births, with the most severe variant, cloacal exstrophy (CE), only occurring in 1 in 200,000. Developmental dysplasia of the hip (DDH) describes a spectrum of disease ranging from mild hip instability to frank dislocation. Underlying malformations, such as myelomeningocele and arthrogryposis, are often associated with the most severe variant of hip dysplasia, teratologic hip dislocation. The varying degrees of severity in DDH have been encountered in classic bladder exstrophy (CBE) patients, but the exact incidence is unknown. We sought to determine the incidence of DDH in CBE and CE patients.

METHODS

We performed a retrospective review of all children with CBE or CE presenting to a single pediatric center between 1994 and 2014. Each chart was reviewed for correct diagnosis of CBE or CE, patient age and demographics, associated medical conditions, pertinent surgeries performed, and the age at operation. Patient imaging was reviewed to determine whether bilateral hip imaging was available.

RESULTS

In a 20-year retrospective review, we identified 66 patients who were diagnosed with either CBE or CE and had available hip imaging (38 males and 28 females). Of these, 11 patients were found to have radiographic evidence of DDH, for an incidence of 16.7% (11/66). Five of these patients had CE, whereas 6 presented with CBE. The first radiographic evidence of DDH was noted at a mean age of 5.75 years (range, birth to 22 y).

CONCLUSIONS

We advocate the use of routine hip screening ultrasound in all infants born with either CBE or CE. Early identification of DDH in these patients may allow additional treatment options to coincide with frequently used osteotomy and orthopaedic interventions.

LEVEL OF EVIDENCE

Level III-retrospective study.

Massive femoral osteolysis secondary to loosening of a cemented roughened long stem: a case report

The surface finish of a femoral stem plays an important role in the longevity of cemented total hip arthroplasty. In efforts to decrease the rate of aseptic loosening, some prostheses have been designed to have a roughened surface that enhances bonding between the prosthesis and cement, but clinical outcomes remain controversial. We present a rare case of massive osteolysis with extreme femoral expansion that developed after cemented revision total hip arthroplasty. The destructive changes in the femur were attributable to abnormal motion of the stem and were aggravated by the roughened precoated surface of the long femoral component. Revision surgery using a total femur prosthesis was performed because there was insufficient remaining bone to fix the new prosthesis. The surgical technique involved wrapping polypropylene meshes around the prosthesis to create an insertion for the soft tissue, which proved useful for preventing muscular weakness and subsequent dislocation of the hip.

Cloacal exstrophy: a single center experience

OBJECTIVE

Cloacal exstrophy is an exceedingly rare and complex anomaly. The records of 23 patients treated in a tertiary care center with limited infrastructure were analyzed for anatomic types, associated anomalies, surgical procedures adopted, and the outcome.

MATERIALS AND METHODS

There were 14 males. Seventeen babies were preterm with an average weight of 1.92 kg. The time of presentation, gestational age, birth weight, position of the hemibladders and associated malformations were noted. Reconstruction procedures involved dismantling of the hemibladders and primary turn in, tubularization of the bowel with an end colostomy, and reconstruction of the abdominal wall. Results of the primary surgical repair, bowel function, and outcome of secondary procedures were analyzed.

RESULTS

The position of hemibladders was lateral in 11, upper confluent in 4 and lower confluent in 8. Associated anomalies were noted in 19 patients. Four patients presented late (>5 days). Five died preoperatively, all had major associated anomalies. Four of them were preterm with average weight of 1.4 kg. Two patients refused surgery. Single-stage surgical reconstruction was done in 15 patients. Five patients died postoperatively because of associated anomalies, prematurity, and sepsis. One patient is waiting for surgery. Six patients had follow-up at 3-42 months and are awaiting further reconstruction. Four patients were lost to follow-up.

CONCLUSIONS

Prematurity, late presentation, and sepsis are the major causes of high mortality noted in this series. In our experience, single-stage reconstruction without osteotomy gives satisfactory results.

Spectrum of cloacal exstrophy

Cloacal exstrophy, one of the most severe congenital anomalies compatible with life, occurs in up to 1 in 200,000 lives births. The condition affects nearly every major organ system with severe neurologic, skeletal, gastrointestinal, and genitourinary ramifications. With increased understanding of the anatomy and embryology combined with refinements in prenatal diagnosis and postnatal care, there is now near-universal survival of patients with cloacal exstrophy. Functional and cosmetic outcomes have improved with modifications in surgical technique. However, debate continues regarding the issue of gender identity, and long-term data are still accruing with respect to the best strategy for management. Despite the extensive malformations noted, many patients have gone on to live fruitful lives.

BILATERAL ANTERIOR PELVIC OSTEOTOMY FOR OLOSURE OF BLADDER EXSTROPHY: DESCRIPTION OF TECHNIQUE

Bladder and cloacal exstrophy are rare malformations associated with abnormalities in the pelvis. The objectives in reconstruction are to obtain a closed and continent bladder, with an acceptable cosmetic appearance. Treatment for the abnormalities of pelvic anatomy is an important part of achieving successful treatment for these urological conditions. This article aims to describe the technique of bilateral anterior pelvic osteotomy for treating bladder and cloacal exstrophy, and presents two cases to demonstrate the difficulties and applications of the technique.

Neuro-orthopedic manifestations of the omphalocele exstrophy imperforate anus spinal defects complex

PURPOSE

The omphalocele-exstrophy-imperforate anus-spinal defects complex is a severe multisystem congenital defect. To comprehensively care for these patients one must appreciate the neurological and orthopedic impact on the overall health of the child.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 73 children with omphalocele-exstrophy-imperforate anus-spinal defects who were treated at our institution, identifying neurological and orthopedic anomalies, ambulatory ability and voiding status.

RESULTS

No neurological data were available on 5 patients. Of the remaining 68 patients 9 had no spinal anomaly, 57 had spina bifida, 1 had hemivertebrae and 1 had coccygeal hypoplasia. We further classified the 47 spina bifida cases as spina bifida occulta in 6, meningocele/lipomeningocele in 12, myelomeningocele/lipomyelomeningocele in 24 and sacral agenesis in 6. Of the patients with spina bifida 35 had cord tethering. Commonly identified orthopedic anomalies were vertebral malformation in 59 patients, scoliosis in 25, clubfoot in 14 and limb length discrepancy in 8. Ambulatory status in 62 patients of walking age revealed that 37 ambulated fully, 15 ambulated with devices, 2 ambulated minimally with devices and 8 were wheelchair bound. Continence data were available on 61 closed cases. Of these patients 26 were incontinent, including 3 with conduit diversion, 1 with ureterostomy and 1 with vesicostomy. A total of 35 patients were socially continent, of whom 30 catheterized via a continent abdominal stoma and 5 voided/catheterized via the urethra.

CONCLUSIONS

Early evaluation for neurosurgical and orthopedic anomalies is vital in these children. Despite the high incidence of spinal pathology most patients ambulate without assistance. Few children with omphalocele-exstrophy-imperforate anus-spinal defects achieve continence via the urethra. Vigilant followup is necessary to identify potentially correctable conditions.

Acrylic bone cements: influence of time and environment on physical properties

Acrylic bone cements are in extensive use in joint replacement surgery. They are weight bearing and load transferring in the bone-cement-prosthesis complex and therefore, inter alia, their mechanical properties are deemed to be crucial for the overall outcome. In spite of adequate preclinical test results according to the current specifications (ISO, ASTM), cements with inferior clinical results have appeared on the market. The aim of this study was to investigate whether it is possible to predict the long term clinical performance of acrylic bone cement on the basis of mechanical in vitro testing. We performed in vitro quasistatic testing of cement after aging in different media and at different temperatures for up to 5 years. Dynamic creep testing and testing of retrieved cement were also performed. Testing under dry conditions, as required in current standards, always gave higher values for mechanical properties than did storage and testing under more physiological conditions. We could demonstrate a continuous increase in mechanical properties when testing in air, while testing in water resulted in a slight decrease in mechanical properties after 1 week and then levelled out. Palacos bone cement showed a higher creep than CMW3G and the retrieved Boneloc specimens showed a higher creep than retrieved Palacos. The strength of a bone cement develops more slowly than the apparent high initial setting rate indicates and there are changes in mechanical properties over a period of five years. The effect of water absorption is important for the physical properties but the mechanical changes caused by physical aging are still present after immersion in water. The established standards are in need of more clinically relevant test methods and their associated requirements need better definition. We recommend that testing of bone cements should be performed after extended aging under simulated physiological conditions. Simple quasistatic and dynamic creep tests seem unable to predict clinical performance of acrylic bone cements when the products under test are chemically very similar. However, such testing might be clinically relevant if the cements exhibit substantial differences.

The posterior approach reduces the risk of thin cement mantles with a straight femoral stem design

BACKGROUND AND PURPOSE

The properties of the cement mantle around a prosthesis are important. We investigated whether the surgical approach to the hip influences the quality and thickness of the cement mantle when using a straight femoral stem design.

METHODS

In a consecutive multi-surgeon series, we reviewed the radiographs of 270 patients after cemented Exeter total hip arthroplasty. 135 stems were introduced using an antero-lateral (transgluteal) approach and 135 stems were introduced using a posterior approach. Anterior-posterior and lateral radiographs were reviewed and cement mantle thickness was measured in Gruen zones 1-14. We graded cement mantle quality according to the Barrack classification.

RESULTS

Barrack grading did not reveal any difference in cement mantle quality between the two groups. AP and lateral radiographs showed no difference in stem alignment between the groups. The risk of a thin cement mantle (< 2 mm) was lower with a posterior approach (OR = 1.8, 95% CI: 1-3; p = 0.03). The greatest risk of a cement mantle thickness of < 2 mm occurred in Gruen zones 8-9 regardless of the surgical approach used.

INTERPRETATION

With a straight femoral stem design, the posterior approach to the hip joint appears to give a lower risk of a thin cement mantle. Irrespective of the approach, there was a risk of thin cement mantles in Gruen zones 8 and 9, which highlights the importance of lateral radiographs in the postoperative radiographic assessment of total hip replacements.

Cloacal exstrophy: a comprehensive review of an uncommon problem

OBJECTIVE

To provide a comprehensive overview of the clinical features, diagnosis, current management strategies, and outcomes of cloacal exstrophy.

METHODS

A PUBMED/Medline search of the literature was performed on cloacal exstrophy focusing on associated anomalies, treatment, and quality of life issues.

RESULTS

The incidence of cloacal exstrophy is between 1 in 200,000 and 400,000 live births. Survival rates now approach 100% secondary to improved understanding of underlying abnormalities and advances in neonatal care and surgical technique. Important principles of initial management include proper nutritional support, early closure of exstrophy, and preservation of intestinal length. The achievement of urinary and fecal continence remains a challenge. Data for long-term outcomes are now emerging which provide new insight into issues of gender identity, function, and psychosocial development of these patients.

CONCLUSION

Cloacal exstrophy remains a rare and complex congenital anomaly, characterized by an array of anatomical defects affecting multiple organ systems. A multidisciplinary approach to management is advocated with a focus on optimization of patient function and quality of life.

Comparative finite element analysis of the debonding process in different concepts of cemented hip implants

Damage accumulation in the cement mantle and debonding of the bone-cement interface are basic events that contribute to the long-term failure of cemented hip reconstructions. In this work, a numerical study with these two process coupled is presented. Previously uniform bone-cement interface mechanical properties were only considered. In this work, a new approach assuming nonuniform and random bone-cement interface mechanical properties was applied to investigate its effect on cement degradation. This methodology was also applied to simulate and compare the degradation process of the cement and bone-cement interface in three different concepts of design: Exeter, Charnley, and ABG II stems. Nonuniform and random mechanical properties of the bone-cement interface implied a simulation closer to reality. The predicted results showed that the cement deterioration and bone-cement interface debonding is different for each implant depending on the stem geometry. Lower cement deterioration was obtained for the Charnley stem and lower bone-cement interface debonding was predicted for the Exeter stem, while the highest deterioration (cement and bone-cement interface) was produced for the ABG II stem.

The exstrophy-epispadias complex

Exstrophy-epispadias complex (EEC) represents a spectrum of genitourinary malformations ranging in severity from epispadias (E) to classical bladder exstrophy (CEB) and exstrophy of the cloaca (EC). Depending on severity, EEC may involve the urinary system, musculoskeletal system, pelvis, pelvic floor, abdominal wall, genitalia, and sometimes the spine and anus. Prevalence at birth for the whole spectrum is reported at 1/10,000, ranging from 1/30,000 for CEB to 1/200,000 for EC, with an overall greater proportion of affected males. EEC is characterized by a visible defect of the lower abdominal wall, either with an evaginated bladder plate (CEB), or with an open urethral plate in males or a cleft in females (E). In CE, two exstrophied hemibladders, as well as omphalocele, an imperforate anus and spinal defects, can be seen after birth. EEC results from mechanical disruption or enlargement of the cloacal membrane; the timing of the rupture determines the severity of the malformation. The underlying cause remains unknown: both genetic and environmental factors are likely to play a role in the etiology of EEC. Diagnosis at birth is made on the basis of the clinical presentation but EEC may be detected prenatally by ultrasound from repeated non-visualization of a normally filled fetal bladder. Counseling should be provided to parents but, due to a favorable outcome, termination of the pregnancy is no longer recommended. Management is primarily surgical, with the main aims of obtaining secure abdominal wall closure, achieving urinary continence with preservation of renal function, and, finally, adequate cosmetic and functional genital reconstruction. Several methods for bladder reconstruction with creation of an outlet resistance during the newborn period are favored worldwide. Removal of the bladder template with complete urinary diversion to a rectal reservoir can be an alternative. After reconstructive surgery of the bladder, continence rates of about 80% are expected during childhood. Additional surgery might be needed to optimize bladder storage and emptying function. In cases of final reconstruction failure, urinary diversion should be undertaken. In puberty, genital and reproductive function are important issues. Psychosocial and psychosexual outcome depend on long-term multidisciplinary care to facilitate an adequate quality of life.

Aseptic loosening, not only a question of wear: a review of different theories

Today, aseptic loosening is the most common cause of revision of major arthroplasties. Aseptic loosening accounts for more than two-thirds of hip revisions and almost one-half of knee revisions in Sweden. Several theories on the cause of aseptic loosening have been proposed. Most of these theories, however, are based on empiric observations, experimental animal models or anecdotal cases. In this review, we discuss the most common theories concerning aseptic loosening. It emerges from this review that aseptic loosening has a multifactorial etiology and cannot be explained by a single theory.

In vitro fatigue behaviour of a cemented acetabular reconstruction

In this study, a hemi-pelvis of composite sawbone was implanted with a Charnley cup using a conventional bone cement and the acetabular replacement was tested under constant amplitude cyclic loads, simulating the maximum hip contact force during normal walking. The damage development in the reconstruction was detected and monitored using CT scanning at regular test intervals, verified by microscopy post testing. Three identical experimental results showed that extensive debonding at the bone-cement interface occurred around the dome region after 20 million cycles.

Genetische und molekularbiologische Aspekte des Blasenekstrophie-Epispadie-Komplexes (BEEK)

The bladder exstrophy and epispadias complex (BEEC) is an anterior midline defect with variable expression involving the infraumbilical abdominal wall including the pelvis, urinary tract, and external genitalia. The incidence varies with regard to ethnical background, sex, and phenotypic expression, and an incidence of 1:20,000 to 1:80,000 has been observed in the middle European population. No gene defect has been attributed to BEEC thus far and chromosomal aberrations or genetic syndromes associated with BEEC have only rarely been reported. According to epidemiological data, a complex genetic as well as a multifactorial mode of inheritance could underlie BEEC. However, no single teratogenic agent or environmental factor has been identified, which could play a dominant role in the expression of the BEEC.A risk of recurrence of 0.5-3% has been described in families with one affected subject. These values correspond to an increased recurrence risk estimated to be as high as 200- to 800-fold when compared to the common population. Due to the paucity of affected sib pairs and suitable multiplex families, conventional linkage analysis to identify candidate genes causally related with BEEC appears to be unfeasible. Large association studies and consecutive linkage disequilibrium mapping should therefore lead to the identification of candidate genes. Also new methods including matrix-based comparative genomic hybridization (CGH) are promising and have successfully been used in the past (e.g., CHARGE association). Moreover, the low incidence of the BEEC requires close cooperation between clinicians in the operative and nonoperative specialties as well as geneticists for successful gene search.

Effects of dorsal flanges on fixation of a cemented total hip replacement femoral stem

BACKGROUND

Although current designs of cemented femoral stems for total hip replacement include both those with and those without a flanged shape at the proximal end, the influence of anteroposterior dorsal flanges on the fixation of the stem is not completely understood. The purpose of this study was to assess the effects of flanges on femoral stem stability and load transfer to the femur with use of an in vitro model.

METHODS

We measured femoral surface strains and three-dimensional micromotion in synthetic femora under cyclic loading with four types of stems: those with flanges and those without flanges in two sizes each. The four types of stems were otherwise identical; that is, all of them were straight, polished, and collarless. Stem-cement micromotion measurements and strain measurements were repeated with three stems of each type, whereas bone-cement micromotion measurements were made with one stem of each type.

RESULTS

Flanges had a greater influence on femoral strains and micromotion than did the difference in the cement thickness resulting from the different stem sizes. Specifically, the flanged stems produced greater strains on the medial femoral surface but smaller strains on the anterior surface than did the non-flanged stems. Flanged stems achieved tighter mechanical interlock within the cement, but these stems increased bone-cement micromotion. Specifically, the motion per cycle of flanged stems within the cement mantle was smaller than that of non-flanged stems, whereas the motion per cycle of the cement mantle within the femoral canal was greater with the flanged stems than with the non-flanged stems.

CONCLUSIONS

Flanges on a total hip femoral stem increase the interlock between the stem and the cement and decrease the proximal-medial stress-shielding. However, these advantages occur with increased bone-cement interface motion, which may be detrimental to the survival of the implant.

Fetal bony pelvis in the bladder exstrophy complex: normal potential for growth?

OBJECTIVES

To provide the first look at the bony histologic features of fetuses with the exstrophy complex, specifically evaluating the endochondral ossification, stage of development, and microscopic potential for normal growth.

METHODS

Three fetuses between 28 and 30 weeks of gestation, one with classic bladder exstrophy, one with cloacal exstrophy, and one control, were obtained from France. The bony pelves were dissected and preserved in formalin, and multiple representative sections were sliced from all pelvic areas: pubis, ischium, ilium, and sacrum. These slices were sequentially processed as slides, stained with hematoxylin-eosin, and evaluated microscopically for histologic changes, developmental stage, and degree of endochondral ossification.

RESULTS

All slides from the three specimens showed cartilage analogue with endochondral ossification. Histologically the exstrophy specimens were identical to the control and appeared completely normal; bone development was occurring at an expected rate with the potential for continued normal growth.

CONCLUSIONS

These new findings illustrate that fetal bone in the exstrophy complex displays normal microscopic growth patterns and unhindered endochondral ossification at 28 weeks of gestation, well beyond the embryologic period. With no evident microscopic bony defect, the gross bony anomalies in exstrophy should be surgically correctable, leading us to conclude that early reapproximation of the physiologic shape of the pelvis could lead to more normal gross bone growth, decreased shortage of bone, and a more appropriate distribution of the mechanical and developmental forces on a closed, normally functioning pelvic ring.

Effects of preheating of hip prostheses on the stem-cement interface

BACKGROUND

Debonding of the cement from metal implants has been implicated in the loosening of cemented total hip prostheses. Strengthening of the stem-cement interface has been suggested as a way to prevent loosening of the component. Previously, it was reported that preheating the stem to 44 degrees C reduced the porosity of the cement at the stem-cement interface. The purpose of this study was to determine the effect of stem preheating on the characteristics of the stem-cement interface.

METHODS

The effects of stem preheating, at temperatures of 37 degrees C, 44 degrees C, and 50 degrees C, on the stem-cement interface were studied in a test model and a preparation that closely simulated the clinical situation. Static interface strength was determined initially and after the stems had been kept in isotonic saline solution at 37 degrees C for two weeks. Fatigue lifetimes were measured, and the nature and extent of porosity at the interface were quantified.

RESULTS

Stem preheating had significant effects on the stem-cement interface. Stems preheated to 37 degrees C had greater interface shear strength than stems at room temperature both initially (53% greater strength) and after simulated aging (155% greater strength). Fatigue lifetimes were also improved, and there was a >99% decrease in interface porosity. The setting time of the cement decreased 12%, and the maximum temperature at the cement-bone interface increased 6 degrees C. Similar effects were found after preheating to 44 degrees C and 50 degrees C.

CONCLUSIONS

Stem preheating had significant effects on the stem-cement interface, with significant improvements in the shear strength and cement porosity of the interface. Also, polymerization temperatures at the cement-bone interface increased. The possible biological effects of these increased interface temperatures at the cement-bone interface require further study.

Early failure of precoated femoral components in primary total hip arthroplasty

BACKGROUND

In an effort to decrease the rate of aseptic loosening, certain cemented femoral components were designed to have a roughened or textured surface with a methylmethacrylate precoating. Reports differ as to whether this step has increased or decreased the rate of failure. This study was designed to evaluate this issue.

METHODS

Five hundred and fourteen hips treated with a cemented Harris Precoat stem (Zimmer, Warsaw, Indiana) were evaluated clinically and radiographically and compared with 254 hips treated with an uncoated Harris Design-2 stem (Howmedica, East Rutherford, New Jersey). Prostheses that had been removed at revision were examined. The cementing and surgical techniques were identical and the population demographics were similar for these two groups.

RESULTS

The mean durations of follow-up were 8.4 and 13.5 years for the Precoat and uncoated Design-2 stems, respectively. At those times, at least forty-nine (9.5%) of the 514 Precoat components and at least ten (3.9%) of the 254 uncoated Design-2 stems had failed (p = 0.006). Five Precoat stems fractured, and no uncoated Design-2 stems fractured. Component failure was associated with use in young, active, heavy men with a diagnosis of avascular necrosis and generally with the use of smaller components. The cementing technique was satisfactory in the majority of the patients, and there were no qualitative differences in cementing technique between the hips that failed and those that did not. The mechanisms of failure of the Precoat prostheses included bone-cement loosening, focal osteolysis, stem fracture, and prosthesis-cement debonding. Fractures of smaller components occurred as a result of fatigue failure and were associated with good distal fixation but proximal stem loosening.

CONCLUSIONS

The rate of failure of roughened, precoated, cemented femoral components was considerably higher and occurred earlier than that of femoral components that were neither textured nor precoated with methylmethacrylate. Younger patients with avascular necrosis had a higher risk of failure; however, this factor alone did not completely explain the differences in outcome between these two components. The causes of aseptic loosening are multifactorial and may be related to component design and size as well as to precoating and surface finish.

OEIS complex (omphalocele-exstrophy-imperforate anus-spinal defects): a review of 14 cases

OEIS complex refers to a combination of defects consisting of omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects. Possible embryologic mechanisms proposed for these findings have included: a single defect of early blastogenesis or a defect of mesodermal migration during the primitive streak period. Fourteen cases with OEIS complex and related malformations were reviewed for demographic features, prenatal and family histories, and clinical, radiological and pathological findings including the frequency and types of associated anomalies. The pathogenetic mechanisms causing OEIS complex and related malformations, such as anorectal and spinal defects, are discussed. The findings in these cases illustrate the spectrum of defects that can occur in the embryologic development of the cloaca and the urorectal septum. Differences in the timing and extent of mesenchymal ingrowth as well as cloacal membrane rupture may account for these variable findings. A developmental field defect involving the intraembryonic mesoderm suggests a possible etiologic role for homeobox genes, such as HLXB9 with mutations, resulting in anorectal and spine abnormalities, or retinoic acid receptors. OEIS complex with its mostly sporadic occurrence suggests etiologic heterogeneity with a possible role for environmental and genetic causes.

Cloacal exstrophy--improving the quality of life: the Johns Hopkins experience

PURPOSE

Exstrophy of the cloaca is a multisystem anomaly involving the gastrointestinal, nervous, musculoskeletal and genitourinary tracts which should be managed with a multidisciplinary approach. Improvement in management has led to survival for the majority of infants, and the focus has shifted to improvement in quality of life. The experience with management of cloacal exstrophy at a large center is evaluated.

MATERIALS AND METHODS

Demographic data as well as functional results of management of the multiple anomalies in 37 patients with cloacal exstrophy were evaluated. Surgical reconstruction was aimed at providing the best functional and cosmetic results.

RESULTS

Average patient age at review was 13.6 years. Most patients (32 of 37) had undergone an initial attempt at bladder closure from birth to greater than 24 months of age. Colostomy was performed when possible and if initial ileostomy was performed, the bowel was augmented later with the hindgut segment. When the hindgut segment was not used for bowel reconstruction, it was preserved for bladder augmentation or genital reconstruction. While urinary continence was achievable in many children, it was usually after augmentation and/or continent diversion.

CONCLUSIONS

Improvements in perinatal management have increased survival in cloacal exstrophy. Therefore, the focus of reconstruction has shifted to reduction in the numbers of incontinent stomas, assistance with ambulation and improved cosmesis. All of these goals are achievable using a multidisciplinary approach to the management of this complex anomaly.

Exstrophic anomalies: recent advances and long-term outlook

Exstrophy-epispadias complex has been a difficult disease to treat. As in the minds of the public and most physicians alike, these children are crippled with life-long ailments and multiple operations. Much of the morbidity of this condition relates to failure to preserve urogenital tract function in these children. In recent years, through better understanding of the exstrophic anatomy and improved surgical techniques, complete repair of the exstrophic anomaly has become possible as soon as the child is born. Results of such closure indicate that such repair is not only feasible but mandatory for a successful outcome. Continence rate and cosmetic appearance are superior to the conventional 3-stage technique. Such repair is also socially acceptable as the parents will bring home a normal-looking baby with much fewer operations expected in the future. It is anticipated that complete one-stage exstrophy closure in the newborn period will revolutionize the outcome of all exstrophy patients.

Vertebral column and spinal cord malformation in children with exstrophy of the cloaca, with emphasis on their functional correlates

Exstrophy of the cloaca is a dramatic malformation whose embryology is poorly understood. While the management of this disorder has received significant attention in the urology and general surgery literature, the neurologic status of these children has been poorly addressed. In order to better characterize the spinal cord and vertebral column malformations found in children with exstrophy of the cloaca, we undertook a clinical review of 26 consecutive children with exstrophy of the cloaca who had been seen at a single institution over 28 years. The prevalence of vertebral malformations in the 25 children who could be evaluated was 25/25 (100%). Twenty (80%) of the children had at least one vertebral fusion, most frequently at T-7. Twenty-two (88%) of the children had at least one vertebra with deficient posterior elements, and the spinal levels most frequently involved were S-2, S-3, S-4 and S-5. Nine (36%) of the children had at least one vertebra with a narrowed interpedicular distance, most frequently at T-7. Nine (36%) of the children had at least one vertebra with atrophic facet anatomy, most frequently at L-3. The prevalence of myelodysplasia in the 19 children for whom spinal magnetic resonance imaging or intraoperative findings were available was 100%. Of these 19 children, 15 (79%) had myelocystocele, 2 (11%) had a lipomeningocele, 2 (11%) had a meningocele, 2 (11%) had hydromyelia, and 4 (21%) had a tethered cord. These data suggest that spinal cord and vertebral column malformations are very common in children with exstrophy of the cloaca.

Anatomical basis of a common embryological origin for epispadias and bladder or cloacal exstrophies

Epispadias, bladder exstrophy and its variants are in the first place usually considered as urological anomalies. Embryological theses and therapeutic approaches are mainly based upon this aspect. We challenge this point of view, in order to bring out a new axis of research about this still misknown pathologic field. A review of 16 cases of bladder exstrophy, 6 epispadias cases, and one cloacal exstrophy case, which had never been described before, revealed that the almost constant bony defect of the pelvic ring was linked with the severity of the visceral features, and with the continence status in epispadias cases. The commonly admitted theories about exstrophy development are based on a primary defect of the cloacal membrane. We suggest that the first anomaly could lie in a lack of rotation in the pelvic ring primordia.

Persistent cloaca and caudal spinal agenesis in calves: three cases

Three newborn calves were affected by caudal spinal dysgenesis or agenesis (coccygeal vertebra) and persistent cloaca. The cloacas were lined by a mixture of transitional and colonic epithelium. The vertebral column of one calf was internalized into the cloaca. The association of persistent cloaca and caudal spinal anomalies is thought to be related to cell loss in the caudal cell mass, which affects caudal spinal column formation and cleavage of the cloaca by the urorectal septum. This association is well documented in humans and has been reported in Manx cats. By extrapolation, it appears likely to exist also in neonatal calves. Identification of cloacal lesions in neonatal animals should be cause for careful examination of the vertebral column because many of the associated spinal lesions are occult.

Early loosening of the femoral component at the cement-prosthesis interface after total hip replacement

Between 1980 and 1990, 1941 total hip replacements were performed with use of the Iowa femoral component fixed with cement. Twenty-seven of these patients (twenty-nine hips) had early loosening of the femoral component two to ten years (average, five years) after the operation. The average age of these patients at the time of the operation was fifty-nine years (range, forty-one to seventy-seven years). The acetabular cup had been inserted without cement in seventeen hips, and the cup had been inserted with cement in twelve. The femoral stems had a matte finish; twenty had been precoated with polymethylmethacrylate and nine had not been precoated. The pattern of loosening of the femoral stem was unique: in each hip, the loosening was initially reflected by debonding (a superolateral lucency between the cement and the prosthesis in zone 1 of Gruen et al.), and this was followed by progressive loosening at the cement-prosthesis interface with maintenance of the bone-cement interface. In twenty hips, the debonding was followed by extensive osteolysis. Twenty patients (twenty-one hips) had a revision, and one was considering a revision at the time of writing. The average time from the onset of the symptoms to the revision for the nineteen hips for which this information was available was nine months. We believe that both the geometry (a cylindrical shape distal to the proximal cobra shape) and the surface finish of the Iowa femoral component were responsible for the pattern of progressive loosening.(ABSTRACT TRUNCATED AT 250 WORDS)

Theories of wear and loosening in hip prostheses. Wear-induced loosening vs loosening-induced wear--a review

The observation of perioprosthetic granulomas containing wear debris around apparently well-fixed as well as around loose-fitting prosthetic components has led to the development of the hypothesis of wear-induced loosening. However, the hypothesis of wear-induced loosening can neither explain the rapid early prosthetic migration detected by roentgen stereophotogrammetry nor the epidemiology of clinical failure without supplementary ad hoc-assumptions. By contrast, apart from explaining the rapid early prosthetic migration detected by roentgen stereophotogrammetry, the theory of early loosening can explain the development of wear granulomas as well as to a great extent the epidemiology of clinical failure.

Cloacal exstrophy: experience with 20 cases

Exstrophy of the cloaca, a rare anomaly, is among the most complex malformations of infancy. Features include omphalocele, imperforate anus, and exstrophy of two hemibladders, between which lies the everted cecum. A small colon ends blindly in the pelvis, and the terminal ileum often prolapses out of the exposed cecum. Formerly, most of these infants died. From 1974 to 1992, 20 of these patients were treated, the majority in the past decade. Six were managed primarily; 14 were referred after prior surgery elsewhere. Current treatment of a newborn with cloacal exstrophy includes closure of the omphalocele, separation of the gastro-intestinal tract from the hemibladders, and closure of the two hemibladders as a single viscus. The colon can be pulled through in some cases, either immediately or later (6 cases). The bladder must be augmented in all cases to provide adequate volume and compliance; stomach is ideal for this (10 cases). A bladder continence mechanism must be constructed by narrowing the outlet (9 cases), or inserting a reversed small bowel nipple (7 cases). Intermittent catheterization is needed for the patient to empty the reconstructed bladder. Although two thirds of these patients are genetic males, they should be raised as females because they lack adequate tissue to construct a phallus. Magnetic resonance imaging of the spine has shown tethering of the cord in all patients; most were released neurosurgically. Lessons provided by these cases demonstrate that a satisfactory surgical and social outcome can be achieved today in most children with cloacal exstrophy.

Musculoskeletal involvement in children with gastroschisis and omphalocele

A review of 58 children with gastroschisis and 8 children with omphalocele showed 14 musculoskeletal problems in 11 children. These problems consisted of limb deformities in 6 children, spinal deformities in 4 children, and osteopenia in 3 children, with 1 of the osteopenic children developing pathological fractures. About one third (5/14) of the problems were arthrogrypotic in nature. The remainder were mild digital deformities, developmental or spondylodysplastic scolioses, and, rarely, congenital spinal deformities.