Computer-assisted total knee arthroplasty using patient-specific templating

Current techniques used for total knee arthroplasty rely on conventional instrumentation that violates the intramedullary canals. Accuracy of the instrumentation is questionable, and assembly and disposal of the numerous pieces is time consuming. Navigation techniques are more accurate, but their broad application is limited by cost and complexity. We aimed to prove a new concept of computer-assisted preoperative planning to provide patient-specific templates that can replace conventional instruments. Computed tomography-based planning was used to design two virtual templates. Using rapid prototyping technology, virtual templates were transferred into physical templates (cutting blocks) with surfaces that matched the distal femur and proximal tibia. We performed 45 total knee arthroplasties on 16 cadaveric and 29 plastic knees, including a comparative trial against conventional instrumentations. All operations were performed using patient-specific templates with no conventional instrumentations, intramedullary perforation, tracking, or registration. The mean time for bone cutting was 9 minutes with a surgical assistant and 11 minutes without an assistant. Computer-assisted analyses of six random computed tomography scans showed mean errors for alignment and bone resection within 1.7 degrees and 0.8 mm (maximum, 2.3 degrees and 1.2 mm, respectively). Patient-specific templates are a practical alternative to conventional instrumentations, but additional clinical validation is required before clinical use.

Consanguineous matings in the Egyptian population

A total of 26 554 Egyptians was ascertained to study the incidence of consanguineous marriages. They were of different ages, different socioeconomic standards, and from different areas. There were 7646 from urban areas, 11 280 from suburban areas, and 7628 from rural areas. The incidence of consanguineous matings in the general population was found to be 28.96% with an average inbreeding coefficient of 0.010, which could be considered high. The highest incidence was that in the rural areas. First cousin marriages occurred more often than the other types of consanguinity.

Human Prop-1: cloning, mapping, genomic structure. Mutations in familial combined pituitary hormone deficiency

Prop-1 is a newly isolated pituitary-specific paired-like homeodomain transcription factor whose cDNA sequence is well known in mouse. To study its involvement in human combined pituitary hormone deficiency (CPHD), we have isolated the human cDNA ortholog and determined the exon/intron organization and chromosomal localization of the human gene. A Prop-1 defect was characterized in three CPHD families. One missense mutation (R73C) involves a residue conserved in 95% of the more than 400 homeodomain proteins so far identified; in vitro splicing assays demonstrated the functional importance of the second defect, whereas the remaining mutation is a frameshift. Given the disease phenotype documented in the patients, these data, which will facilitate molecular investigations in other patients, demonstrate the crucial role of Prop-1 in the proper development of somatotrophs, lactotrophs, thyreotrophs and gonadotrophs.

Radiation exposure to the hands of orthopaedic surgeons: are we underestimating the risk?

INTRODUCTION

Previous studies reported that the radiation exposure to the hands of orthopaedic surgeons was far below the acceptable limit. However, the risk could have been underestimated as some factors were overlooked, namely monitoring trainees during average workload, placing dosimeters over the most susceptible locations, measuring the cumulative dosage of radiation and considering the dose limit for non-classified workers.

MATERIALS AND METHODS

We performed a prospective study in two centres to estimate the radiation dose to the hands of two consultant trauma surgeons and two trainees (one assisting and one operating) while performing 47 fluoroscopy-assisted procedures. We used validated thermoluminescent dosimeters (TLDs) rings and fingerstalls for monitoring the cumulative dosage.

RESULTS

Trainees were at higher risk while performing intramedullary nailing and during assistance. Higher radiation doses were recorded from dominant index fingers and particularly fingertips.

CONCLUSION

The risk of radiation exposure appears to be higher than previously reported. Fingertips are more susceptible to radiation exposure and should therefore be monitored in forthcoming studies.

Reconstructive surgery in spinal tumours

AIMS

This study reports 21 patients who underwent reconstructive surgery for destructive spinal tumours.

MATERIALS AND METHODS

The mean age was 49 years (range: 39-71 years). Primary lesions were met in two cases. Secondary spinal tumours were diagnosed in 19 cases. Thirteen were breast carcinoma metastases (61.9%). The cervical spine was involved in four cases, thoracic spine in six cases, and the lumbar spine in 11 cases. One patient underwent decompression laminectomy and posterior pedicle screw stabilization. The others underwent tumour tissue excision, with spinal reconstruction with autogenous bone grafting, with or without vertebral body replacement prosthesis. Anterior and posterior stabilization of the vertebral column was also used.

RESULTS

The objectives of surgery were achieved, in that early ambulation, easier nursing care, pain relief and neurological recovery were reported in all cases. No surgery-related complications were encountered.

CONCLUSIONS

We recommend surgical intervention for such lesions where reasonable longevity is anticipated.

Genetic susceptibility in pityriasis versicolor

300 patients with pityriasis versicolor, 168 males and 132 females, of different ages were included in this study. Each was subjected to a detailed structured questionnaire. All the available relatives had been examined. Pedigrees were constructed and segregation analysis was done using the mathematics of population genetics. The collected data showed genetic susceptibility which is inconsistent with any of the single gene defects but fulfill the criteria of multifactorial (genetic-environmental) inheritance. The heritability was estimated to be 22.2% in the first-degree relatives.

HLA-antigens and tuberculosis in the Egyptian population

Peripheral blood lymphocytes from 42 unrelated Egyptian patients with tuberculosis and 156 healthy persons were HLA phenotyped for the A,B and DR loci using the NIH lymphocytotoxicity tests. Statistical analysis of the results showed that A2 and B5 had significantly increased frequencies among patients with tuberculosis compared with the controls. Patients with A2 had more severe disease than did patients without A2 and the number with B5 antigen was less than those without the antigen. This observation suggests that A2 and B5 may influence susceptibility to tuberculosis, but not the course of the disease. Furthermore, a linkage disequilibrium was found between A2 and B5 antigen among tuberculous patients, but their association bore no relation to the severity of the disease.

Improved erythrocyte survival with combined vitamin E and selenium therapy in children with glucose-6-phosphate dehydrogenase deficiency and mild chronic hemolysis

To study the antioxidant effect of high-dose vitamin E alone and in combination with selenium in patients with glucose-6-phosphate dehydrogenase deficiency with mild chronic hemolysis, 36 male children with such manifestations were enrolled consecutively into two equal groups. Group 1 received 800 IU vitamin E daily, and group 2 received 800 IU vitamin E in combination with 25 micrograms selenium. Hematologic status before and 2 months after treatment was evaluated. After treatment there was a significant change toward normal in both groups. The mean red cell half-life increased in group 1 from 16.9 to 22.8 days (P less than 0.01), and in group 2 from 15.6 to 24.3 days (P less than 0.01). A comparison of the mean difference of paired values in the two groups revealed a more significant increase in hemoglobin (0.9 +/- 0.1 gm/dl vs 1.2 +/- 0.2 gm/dl, P less than 0.05), hematocrit (2.4% +/- 0.4% vs 3.8% +/- 0.3%, P less than 0.05), and red cell half-life (5.9 +/- 3.0 days vs 9.1 +/- 4.4 days, P less than 0.01), and more significant reduction in reticulocytes (-0.7% +/- 0.2% vs -1.5% +/- 0.4%, P less than 0.01) in group 2. Clinical assessment and follow-up indicated no side effects related to the drugs.

Spinal dysraphism: experience with 250 cases operated upon

During a period of 4 years (December 1983-December 1987) 250 children were operated upon by the authors. At the outpatient clinic of the New Children's Hospital 313 infants and children suffering a myelodysraphic lesion were seen, 63 of whom were not treated surgically owing to the presence of severe hydrocephalus in 16 cases and complete flaccid paraplegia with marked sphincteric disturbances in 47. All of the patients came from poor families. Malnutrition, many siblings per family, poor maternal care, and repeated pregnancies and abortions have added to the large incidence of such a handicap in Egypt. The clinical features, diagnosis, and management of 200 cases of spinal bifida aperta (SBA) and 50 of spina bifida occulta (SBO) are summarized. SBA cases were operated upon as soon as possible from the time of their presentation; their preliminary assessment included an exhaustive general, neurological, urological, and orthopedic examination; and investigations such as plain X-rays to the back and skull, CT scanning of the cranium, spinal myelogram, and metrizamide CT scanning to the back were performed. The surgical outcome is far from being satisfactory in the sense of producing an ambulatory, intelligent, healthy individual, especially in a meningomyelocele patient having a high-level lesion. The authors believe that there is still much to be done for these children marked by fate, and the neurosurgeon should be one among several other physicians devoted to the amelioration or at least the prevention of worsening, if possible, of the condition in such unfortunate and handicapped children.

Evidence of chromosomal instability in neurofibromatosis

Blood lymphocytes from six unrelated patients with neurofibromatosis and three normal controls were examined for their response to different doses (0, 75, 150, 300, 400 rad) of x-radiation, as measured by chromosome aberrations (gaps, breaks, dicentrics, centric rings, acentric ring, fragments, and minutes). Cytogenetic studies on phytohemagglutinin-stimulated cells revealed chromosomal instability in the neurofibromatosis lymphocytes as shown by the significant increase in the in the incidence of gaps, breaks and dicentrics. This increase paralleled the increase in the dose of irradiation. The significance of these findings is discussed.

Hepatocellular carcinoma in Egyptians with and without a history of hepatitis B virus infection: association with hepatitis C virus (HCV) infection but not with (HCV) RNA level

The aim of this study was to analyze the association of hepatocellular carcinoma (HCC) with hepatitis C virus (HCV) in Egypt, using hepatitis B virus (HBV) and hepatitis E virus (HEV) as virus controls. In addition, the association of HCC with HCV RNA levels among persons seropositive for HCV was analyzed. We compared 131 patients with proven HCC, 247 with bladder cancer, and 466 healthy hospital employees. Age, sex, and place of residence were recorded to study confounding factors. Among the healthy controls, 16% were seropositive for HCV, 21% for HBV, and 31% for HEV. When healthy controls were age-matched with HCC patients, the latter were significantly (P < 0.001) more often HCV seropositive (67%) than were the controls (30%). The seropositivity for HBV and HEV did not differ significantly in frequency between the two groups. The seropositivity for HCV was also significantly (P < 0.001) more often found in HCC patients (76%) than in BC patients (47%), with seroprevalences for HBV and HEV not differing significantly in these age-matched groups. In HBV-negative HCC and bladder cancer patients, seroprevalence for HCV was significantly (P = 0.002) higher in HCC patients (68%) than in bladder cancer patients (36%). This difference was even more pronounced (P < 0.001) in HBV-positive HCC and bladder cancer patients (78% versus 52%, respectively). Of HCV-seropositive individuals, 49% were HCV RNA positive by branched DNA assay, and of these, 96% were infected by HCV genotype 4. No correlation between HCV RNA load and seropositivity of HBV or age or disease state was found. Infection with HCV and HCV-HBV double infection, but not HBV or HEV infection alone, is strongly correlated with HCC in Egypt.

HLA antigens and acute rheumatic fever: evidence for a recessive susceptibility gene linked to HLA

From 60 probands with acute rheumatic fever (ARF), 19 multiplex families segregating for ARF were ascertained. The parents and rheumatic and normal sibs of the probands in these 19 families were also studied. HLA typing using the microlymphocytotoxic assay was then performed on the 60 unrelated probands, the multiplex families, and 234 unrelated controls using 23 antigens from the HLA-A and -B loci. The controls lacked a past history of ARF and were from the same geographic locality. Calculations of relative risk demonstrate an increase of HLA-B5 antigen in the 60 patients, but the result might not be significant from the point of view of multiple comparisons. Nevertheless, affected sib pairs from the multiplex families show 93% concordance for both or one HLA haplotype. A formal linkage analysis demonstrates that a recessive etiology is most likely (lod score of 3.3) with approximately 68% of cases being due to a gene closely linked to HLA and in linkage disequilibrium with HLA-B5. The remaining 32% of cases are due to other familial factors such as polygenic inheritance or common environmental factors. The results confirm a strong genetic predisposition to ARF and its heterogeneous nature in families.

A new beta-thalassemia mutation produced by a single nucleotide substitution in the conserved dinucleotide sequence of the IVS-I consensus acceptor site (AG----AA)

An Egyptian child with thalassemia major was found to carry two different haplotypes (I and VI) associated with two beta-thalassemic chromosomes. Analysis with several oligonucleotides and restriction enzymes, which identify the mutations most common in the Mediterranean area, allowed the identification of only one mutation, namely T----C at position 6 of the first intervening sequence (IVS-I). In order to characterize the other mutation the beta gene was amplified with polymerase chain reaction and sequenced. A G----A substitution was found at position 130 of the IVS-I which alters the conserved dinucleotide AG present in the consensus acceptor sequence, thus producing a beta (0)-thalassemia. This mutation was further confirmed by restriction analysis since it creates a new restriction site for the enzyme Afl II. It is concluded that this subject carries the IVS-I-6 mutation associated with haplotype VI, frequently observed in Mediterranean areas, and a new mutation at the acceptor site of the IVS-I, which has not been described before, associated with haplotype I. This thalassemic gene can be added to the list of mutations that can be identified by Southern analysis using Afl II.

Immunogenetic susceptibility for post-schistosomal hepatic fibrosis

In 19 children with hepatic fibrosis as the result of continued schistosomiasis mansoni and 20 children without hepatic fibrosis, the following studies were carried out: HLA antigen typing for 30 antigens, immune response of T lymphocytes to schistosome antigen by measuring DNA synthesis evidenced by 3H-thymidine uptake, and measurement of total OKT3+, OKT4+, and OKT8+ cells using monoclonal antibodies. Patients with hepatic fibrosis were mostly high responders in contrast with those without fibrosis. High immune response and susceptibility to post-schistosomal hepatic fibrosis were associated with a high frequency of A2 and B12 antigens and a lack of DR2 antigens, while low response was associated with the presence of the DR2 antigen. The T4+:T8+ ratio showed increased suppressor proportions in patients with low immune response and/or with no hepatic fibrosis. We suggest an immunogenetic susceptibility for post-schistosomal hepatic fibrosis, probably controlled by HLA-linked genes via the suppressor T cells.

HLA antigens and idiopathic epilepsy

Fifty-two mentally normal Egyptian children with idiopathic epilepsy were human leukocyte antigen (HLA) typed. They were divided into two subgroups: generalized tonic-clonic seizures (36 cases) and absences (16 cases). When the frequencies of HLA antigens were compared statistically with those of 120 normal controls, HLA-A9 was found to be significantly higher in the total epilepsy group and the two subgroups. This finding, together with the low HLA-A9 gene frequency in our group of normal Egyptians as compared with other ethnic populations, strongly suggests an association between antigen A9 and one or more of the polygenes controlling the development of idiopathic epilepsy. The relative risk indicated that persons having antigen A9 are 16 times more susceptible to epilepsy than persons lacking it.

Characterization of spinal cord lesion in patients attending a specialized rehabilitation center in Bangladesh

STUDY DESIGN

This study was designed as a cross-sectional study.

OBJECTIVES

The objective of this study was to find out the clinical types and sociodemographic characteristics of patients with spinal cord lesion (SCL).

SETTING

Centre for the Rehabilitation of the Paralysed (CRP).

METHODS

Data were collected by face-to-face interview, with a structured interview schedule from admitted patients. Descriptive measures and χ(2)-test were applied for data analysis.

RESULTS

Of 107 patients, majority (20%) belonged to age group of 25-29 years (mean 31±12.2 years). About 83% were males; 65% married and 54% illiterate. Agricultural and other day laborers constituted the major occupation groups with mean monthly family income of US $60 (±$53). About 92% came from rural area and 84% belonged to nuclear family. About one-third of the patients were referred by the medical college hospitals. About 65% of the patients were admitted at 1-29 days of lesion with longest duration of 3 years. Patients were mostly (93%) traumatic. Fifty-four percent had paraplegia and most common skeletal level segment was cervical (44%). About 43% had pressure sores at admission. Eighty-nine percent needed management for bladder function through the use of catheter. Age, sex and occupation were associated with type of paralysis, skeletal level of injury and neurological condition; physical status, causes of lesion, type of injury and skeletal level of injury; and skeletal level of injury, respectively (P<0.05).

CONCLUSION

Major cause of SCL was traumatic. Available treatment facilities were inadequate and needed improvement through government and private initiatives.

"Failure" of forearm intramedullary elastic nails

Elastic nails are an established modality for treating forearm fractures in children. These nails are usually removed 6-9 months after surgery as refracture may occur in 10% of cases if the nails removed earlier. We report a case of refracture of the forearm bones with elastic nails in situ, 5 months after the original fractures. The fracture was angulated approximately 80 degrees with the apex pointing anteriorly. Closed reduction was difficult and resulted in breakage of the ulnar nail. The authors describe the details and outline the management of this unreported complication.

Chromosomal analysis of neuroblastoma

Ten children with abdominal neuroblastoma were included in the study. Biopsies from the neuroblastomas were taken during surgical operations, nine from the primary tumours and one from a metastasis. Histopathology was done for diagnosis. Chromosomal cultures of neuroblastoma cells and peripheral blood lymphocytes were performed. The peripheral blood lymphocytes revealed normal chromosomal complements. The 10 tumours were in the peridiploid range with random gains or losses of chromosomes. Deletion of the short arm of chromosome number 1 distal to band p31 occurred in 6 tumours. Other structural changes and giant markers were found. It was concluded that a regulatory gene controlling the transformation gene of neuroblastoma, is present at or distal to lp31.

HLA-antigens in Guillain-Barré syndrome

A microlymphocytotoxicity test determined serologically the frequency of HLA antigens in 32 patients with Guillain-Barré syndrome and in 234 healthy control subjects. The results demonstrated significantly increased frequencies of A3 and B8. The relative risk was estimated to be 9.6 and 4.6 for the A3 and B8 antigens, respectively. Study of the gametic association revealed weak positive linkage disequilibrium and biological association. The results are discussed, and it is concluded that the aberrant genetic make-up of the patients makes them more susceptible to develop the syndrome after exposure to the environmental factor(s).

HLA-antigens in the Egyptian population

HLA-A, -B and -DR markers were determined for 380 normal unrelated Egyptians of both sexes. Typing for 9 A-locus, 15 B-locus and 6 DR-locus alleles was done. Antigen, gene and haplotype frequencies and delta-values were estimated. The data obtained were statistically compared to those of Arabs at Gaza Strip, European and American Caucasians, American Blacks, African Blacks and Japanese (Orientals). The Egyptian genetic make-up was found to be heterogenous and some HLA markers differ significantly from that of other ethnic groups as well as Arabs from the Gaza Strip.

Enhanced response to the induction of sister chromatid exchange by gamma radiation in neurofibromatosis

The study included 8 unrelated patients with neurofibromatosis, and 10 unrelated normal and healthy persons as controls. Whole blood samples were divided into plastic T flasks and exposed at room temperature to gamma rays. The radiation dose was 36 rad/minute, and the doses delivered were 0, 75, 150 and 300 rad. The lymphocytes were cultured in (RPMI) 1640 tissue culture medium and autologous serum (20%). Phytohemagglutinin and bromodeoxyuridine (Brdu) (10 microM) were added at initiation of culture and harvesting was done 64 to 68 hours after culture initiation. Slides were coded, differential staining was done, and sister chromatid exchanges (SCEs) and aberrations (gaps, breaks, dicentrics, fragments and minutes) were counted. In the controls no significant increase in frequency of SCE has been found (P greater than 0.5). In the patients, the frequencies significantly increased with the increase of dose of irradiation (P less than 0.001). Furthermore, after irradiation, the incidence of gaps, breaks, and dicentrics were significantly increased in patients compared with controls. Moreover, the incidence increased with the increase in the dose of radiation. The results are discussed with a conclusion that the results add to the indication of a genetic predisposition to develop cancer in neurofibromatosis patients.

Closed talar body fracture with talonavicular dislocation; a case report

Closed fracture dislocation of the body of the talus is rare. The dislocation of the subtalar and ankle joints (associated with fracture body) has been reported and already described in the current classifications. We report a case of closed fracture of the body of the talus associated with talonavicular dislocation. Open reduction and internal fixation was performed after failed attempt of closed reduction. The fracture has healed and there is no evidence of avascular necrosis after 2 years follow up. We recommend early evaluation of this injury by CT scan or by proper radiographic views under sedation and urgent open reduction if one attempt at closed reduction has failed.

Immunogenetic study of the response to streptococcal carbohydrate antigen of the cell wall in rheumatic fever

An immunogenetic study of the response to streptococcal carbohydrate antigen of the cell wall was carried out on members of 15 multiplex families each having more than one sib affected with rheumatic heart disease. They comprised 30 parents and 61 sibs (32 with rheumatic disease and 29 without). Fifty healthy unrelated subjects served as controls. A history was taken and clinical examination carried out. Rheumatic activity was determined and HLA typing was carried out for nine A antigens, 15 B antigens, and six DR antigens. The immune response of lymphocytes to streptococcal polysaccharide antigen of the cell wall of group A beta haemolytic streptococci in vitro was studied by tritiated thymidine uptake. The results were statistically and genetically analysed. It was found that (a) all subjects with rheumatic disease were highly responsive to the streptococcal polysaccharide antigen of the cell wall, the sib pairs being mostly HLA identical; (b) all low responders had no rheumatic disease and their phenotypes were mostly different from those of the rheumatic member of their sib pair; (c) correlation of immune responsiveness (high or low) between HLA-identical sibs was significant, but insignificant between haplotype identical and non-identical sibs; (d) the gene responsible for high responsiveness to the streptococcal polysaccharide antigen of the cell wall is recessive and closely linked to HLA. In conclusion, it was found that exposure to pharyngeal infection with group A beta haemolytic streptococci may lead to acute rheumatic fever in those with an inherited recessive gene responsible for high responsiveness to the streptococcal polysaccharide antigen of the cell wall.