The intraoperative use of a calliper predicts leg length and offset after total hip arthroplasty. Component subsidence influences the leg length.

BACKGROUND: The purpose of total hip arthroplasty (THA) post-surgery and proper physiotherapy is positive recovery for the patient. Consideration is given to hip replacement biomechanics by ensuring no discrepancies in limb length (LL) and a stable prosthesis. Therefore, the patient must have proper preoperative planning and communication and a clear understanding of what to expect. METHODS: A prospective series of 59 THA operated by a single surgeon via Hardinge approach was studied, using an intraoperative calliper (CAL) to predict the change of LL and offset. We compared the results of the intraoperative changes before and after THA implantation with the reference of these values on anteroposterior x-ray pelvis. The importance of leg length balance and a good offset restoration is questioned, and the effect of component subsidence on leg length is considered. RESULTS: The average preoperative leg length discrepancy was -6.0 mm, postoperatively +3.6 mm. There was a strong correlation between the CAL measurements and the values on the x-ray (LL, r=0.873, p<0.01; offset, r=0.542, p<0.01). Reliability is better for limb length than for offset. These results are comparable within the literature and the statistical results from other studies reviewed. In addition, we evaluate the importance of subsidence of the prosthesis components for long-term results. CONCLUSION: The intraoperative use of CAL gives excellent results in predicting the final LL and offset after THA. Considering subsidence of prosthesis components, a target zone around +5 mm might be more suitable for leg length directly postoperatively. Moreover, surgeons must discuss the topic of leg length discrepancy (LLD) intensively with the patient pre-operatively. LEVEL OF EVIDENCE: Level 4, prospective cohort study.

Comparative dose levels between CT-scanner and slot-scanning device (EOS system) in pregnant women pelvimetry.

PURPOSE: To estimate fetal absorbed doses for pregnant women pelvimetry, a comparative study between EOS imaging system and low-dose spiral CT-scanner was carried out. For this purpose three different studies were investigated: in vivo, in vitro and Monte Carlo calculations. METHODS: In vivo dosimetry was performed, using OSL NanoDot dosimeters, to determine the dose to the skin of twenty pregnant women. In vitro studies were established by using a cubic phantom of water, in order to estimate the out of field doses. In the latter study, OSLDs were placed at depths corresponding to the lowest, average and highest position of the uterus. Monte Carlo calculations of effective doses to high radio-sensitive organs were established, using PCXMC and CTExpo software suites for EOS imaging system and CT-scanner, respectively. RESULTS: The EOS imaging system reduces radiation exposure 4 to 8 times compared to the CT-scanner. The entrance skin doses were 74% (p-values <0.01) higher with the CT-scanner than with the EOS system. In the out of field region, the measured doses of the EOS system were reduced by 80% (p-values <0.02). Monte Carlo calculations confirmed that effective doses to organs are less accentuated for EOS than for CT pelvimetry. CONCLUSIONS: The EOS system is less irradiating than the CT exam. The out-of-field dose which is significant, is lower in the EOS than in the CT-scanner and could be reduced even further by optimizing the time used for image acquisition.

[A technic of magnetic resonance tomographic pelvimetry in obstetrics]. / Technik der kernspintomographischen Beckenmessung in der Geburtshilfe.

Magnetic resonance imaging (MRL) allows for the first time direct determination of maternal pelvic dimensions without ionising radiation. Phantom measurements and the correlation with traditional pelvimetric measurements in 10 patients after Caesarean section have shown mean differences of +/- 2 mm, with a maximum of 5 mm. The evaluation of pelvic configuration is obtained analogous to the conventional roentgenogram. In addition to conventional or digital x-ray pelvimetry, the soft tissues of the maternal pelvis and the presenting part of the foetus is delineated with high contrast. Positioning in the body coil can be accomplished even late in pregnancy or in impending labour, acceptance by the pregnant women being high. Whereas in a given indication after delivery conventional x-ray pelvimetry continues to be performed, antenatally MRI pelvimetry has now been established in our Departments as the method of choice--based on meanwhile 107 examinations. Present drawbacks are the relatively high cost and the limited availability of MR units.

[MR pelvimetric reference values]. / MR-pelvimetrische Referenzwerte.

Complete pelvimetry can be easily performed via MR. As shown by comparing the measurements of 4 observers its reproducibility is acceptable. The reference diameters obtained on 53 patients by MR are in 7 out of 9 dimensions larger than those of anatomical and obstetrical textbooks, which have not changed in the last 100 years. Hence, with the general increase in population size an increase in pelvic diameters has taken place.

The accuracy of the Palpation Meter (PALM) for measuring pelvic crest height difference and leg length discrepancy.

STUDY DESIGN: Test-retest reliability and validity. OBJECTIVE: To determine the validity and reliability of the Palpation Meter (PALM). BACKGROUND: Leg length discrepancy (LLD) has been associated with a variety of musculoskeletal disorders. Therefore, the clinical measurement of LLD has become a routine and important part of the physical examination. The PALM is an instrument that was recently developed to indirectly measure LLD, but little is known about its measurement properties. METHODS AND MEASURES: Fifteen healthy and 15 symptomatic subjects with suspected LLD participated in this study. Measurements of pelvic crest height difference (PD) were obtained by 2 examiners using the PALM. A standing antero-posterior (AP) radiograph of each subject's pelvis was taken, and PD and LLD (femoral head height difference) were determined from the radiograph for comparison with the PALM values. Intraclass correlation coefficients (ICCs) were calculated to determine the validity and reliability estimates of the PALM. RESULTS: For all subjects, the validity estimates (ICC2,3) of the PALM for PD were excellent (0.90 for rater 1 and 0.92 for rater 2) when compared with the standing AP radiograph of the pelvis. The PALM was less accurate (ICC2,3 of 0.76 and 0.78 for rater 1 and 2, respectively) as an indirect estimate of LLD. Intrarater reliability for each rater was excellent (ICC3,3 = 0.97 and 0.98) and interrater reliability was very good (ICC2,3 = 0.88). CONCLUSION: The PALM is a reliable and valid instrument for measuring PD. Clinicians should consider this convenient, cost-effective clinical tool as an alternative to radiographic measurement of pelvic crest height difference.

Ultrasonic pelvimetry. A method for preliminary estimation of the pelvic outlet.

Vaginal sound, with transmitter crystals of 2 MHz, is used when measuring the interspinous diameter. The echo from pelvic wall, the effect on the measured spinal diameter by altering the position of the ultrasonic transmitter, and the influence of air or faeces between the ultrasound transmitter and the pelvic wall, have been analysed in a series of model trials on a dummy submerged in water. Thereafter clinical trials were performed on 102 women, pregnant in their 9th month. The results obtained when measuring the interspinous diameter on the ultrasonic tomogram were compared with the results obtained when measuring the same distance on a frontal x-ray picture taken using the orthographic technique according to Borell-Frenström. The method is suitable for selecting those cases with suspect constriction of the pelvic outlet for an x-ray examination by the Borell-Fernström technique.

[Computerized tomography pelvimetry: recent advances]. / Lapelvimétrie par scanner: récentes évolutions.

We describe a new technique of pelvimetry by computerized tomography (CT), using multislice-CT. This new technique can provide measurements of the classical diameters and is able to bring new informations on anatomical aspect of the bony pelvis, especially of the superior strait, with images easier to understand by obstetricians and midwives. It is a simple technique to perform, without increasing cost. No additional irradiation is needed, but this point has to be confirmed by multicenter evaluation.

[An error in the determination of the bi-ischial diameter by the Thoms grid (author's transl)]. / Erreur sur la détermination du diamètre bi-épineux par la grille de Thoms.

After recalling the principles of homothetics which are the basis of radiological pelvimetry by the Thoms method, the authors carry out a study of the pelvimetry accessory presently the most distributed in France. It turns out that the grid introduces an error that, depending upon the conditions under which it is used, can reach levels of 4% underestimation. This error of 4% of something that itself is merely a calculation has little impact since it only affects 8% of the results.

[Use of a microprocessor for pelvimetry (author's transl)]. / Application d'un micro-processeur à la pelvimétrie.

Calculating machines have made the use of Thoms grid unnecessary, and have many advantages: the exact measurements of the different diameters can be obtained, and it is now possible to establish a more precise prognosis by introducing supplementary data such as those obtained by ultrasonography.

[Low dose helical CT pelvimetry: evaluation of radiation dose and image processing]. / Pelviscanner hélicoïdal en basse dose: évaluation de la dose d'irradiation et du traitement d'images.

PURPOSE: to estimate from phantom measurements the radiation dose and the accuracy of helical ct pelvimetry. MATERIALS AND METHODS: Eight helical CT acquisitions using different tube current (100, 50, 25 or 10mAs) and pitch factor (1.125 or 1.375) settings but identical collimation (2mm) and kilovoltage (120 kVp) were evaluated using a four-channel MDCT scanner and compared with conventional CT pelvimetry including a single scout and two transverse images. A plexiglas phantom combined with an ionization chamber was used to calculate the CTDIw and DLP for each acquisition. Then, an ex vivo phantom of bony pelvis was used to evaluate the accuracy of helical acquisitions for the measurement of pelvic diameters (i.e. the antero-posterior inlet, the transverse inlet and the interspinous distance). Reconstructions of helical acquisitions were performed using 2D MPR, 3D MIP and 3D SSD algorithms. RESULTS: CTDIw and DLP of conventional pelvimetry were 26 mGy and 42 mGy.cm respectively. The radiation dose of helical acquisitions decreased linearly with tube current (CTDIw: from 13 to 1.3 mGy, DLP: from 218.3 to 18.7 mGy.cm). Compared to conventional CT, the dose was nearly similar at 25 mAs and reduced at 10 mAs. Helical acquisitions provided accurate measurements of pelvic diameters with a pitch of 1.125 and a 2D MPR algorithm to evaluate the AP inlet and a 3D MIP algorithm to evaluate the transverse inlet and the interspinous distance. Variations of tube current did not influence the accuracy of pelvic diameter measurement. CONCLUSION: Our results suggest that accurate low-dose helical CT pelvimetry using 10-25 mAs and a pitch factor of 1.125 combined with 2D MPR and 3D MIP reconstructions is possible.

CAD modeling of the birth process. Part II.

We are engaged in studying the process of human birth by developing a computer-based dynamic model that can be adapted to specific birth scenarios. The individual characteristics of a given pregnant woman and fetus, embedded in their clinical measurements and CT and MRI images, are captured in the model. One can thereby predict adverse events that might happen during labor and delivery. Based on our findings from a preliminary design and execution of this model, we believe it holds great promise as an accurate, cost-effective diagnostic and teaching tool that will help predict conditions during individual labor scenarios that might cause traumatic birth injuries, and thereby enable us to make the most informed clinical decisions possible.

An appraisal of computed tomography pelvimetry in patients with previous caesarean section.

This study was conducted to determine the value of computed tomography (CT) pelvimetry in patients with previous caesarean section. Of 219 pregnant women with one previous caesarean section, 100 had antenatal CT pelvimetry and a control group of 119 women had no CT pelvimetry. In the CT pelvimetry group, 51.0% delivered by caesarean section, 28.0% underwent elective caesarean section for contracted pelvis based on the findings of CT pelvimetry and 23% underwent emergency caesarean section after a trial labour. In the control group, 21.8% underwent emergency caesarean section. The differences in birth weight and Apgar scores between the groups were not statistically significant. CT pelvimetry increased the rate of caesarean delivery, suggesting that CT pelvimetry before a vaginal birth after a previous caesarean delivery is of limited value.

[Intraobserver and interobserver variation in measurement of the pelvic diameter using DeLee's internal pelvimeter in Cesarean section]. / Intra- og interobservatørvariation ved måling af conjugata vera obstetrica med DeLee's interne pelviometer ved sectio caesarea.

The method of measuring the true conjugata with DeLee's Internal Pelviometer at caesarean section was evaluated. In 58 women the true conjugata were blindly measured three times by the surgeon and also, in fifty cases, three times by the assistant. Only a slight intraobserver difference was found: median range was 0.42 cm. There was no significant interobserver variation. We conclude that DeLee's Internal Pelviometer can be used to measure the true conjugata at caesarean section, but the use of pelviometry in modern obstetrics is questioned.

An evaluation of the EOS X-ray imaging system in pelvimetry.

OBJECTIVES: To demonstrate the reliability of the EOS imaging system in measuring the internal diameters of the bony pelvis. MATERIALS AND METHODS: A prospective study comparing the results of the pelvimetry of 18 dry pelvises carried out on the EOS imaging system to measurements taken manually and using the two current gold standard CT methods. Pelvimetric measurements of each pelvic bone were obtained using four methods and compared: direct manual measurements, spiral and sequential CT pelvimetry, and 2D-3D low-dose biplanar X-rays. The various obstetric diameters were measured to the millimetre and compared. RESULTS: There was no significant difference in the different diameters assessed, with the exception of the interspinous diameter. There was a highly significant correlation (P < 0.001) between the values measured manually and by EOS for the Magnin index (Pearson = 0.98), the obstetric conjugate diameter (Pearson = 0.99), and the median transverse diameter (Pearson = 0.87). CONCLUSION: The EOS imaging system allows for an ex vivo determination of the obstetrical diameters that is reliable enough to estimate obstetric prognosis, producing comparable measurements to CT. In view of concerns about protection from radiation, this low-dose imaging technique could become, after in vivo prospective validation, the new gold standard for pelvimetry and therefore a good alternative to CT.

Pelvimetry in Squirrel Monkeys (Saimiri scireus Linnaeus, 1758) / Pelvimetria em macacos-de-cheiro (Saimiri scireus Linnaeus, 1758)

Saimiri sciureus is a neotropical primate widely used in research. However, there are still difficulties regarding their reproduction in vivaria due to the high incidence of dystocia. Dystocia in primates can be caused by cephalopelvic disproportion and in Squirrel Monkeys, pregnancy of large fetuses were reported. This paper describes pelvimetry data of adult females and subadults in specimens of Squirrel Monkeys, from a research colony of Para, Brazil. Pelvic radiographs were obtained in ventrodorsal projections and the following measurements were taken: superior bi-iliac diameter (SBID); inferior bi-iliac diameter (IBID); bi-iliac average diameter (BIAD); right diagonal diameter (RDD); left diagonal diameter (LDD); sacro-pubic diameter (SPD); Based on the obtained diameters, the entrance area of the pelvis (EAP) was also calculated. The average values of the pelvic diameters and EAP in adult females were SBID 1.714cm, BIAD 1.957cm, IBID 1.686cm, RDD 2.771cm, LDD 2.764cm, SPD 2.543cm and EAP 3.9056cm2; and subadult females: 1.588cm SBID, 1.850cm BIAD, 1.625cm IBID, 2.50cm RDD, LDD 2.474cm, 1.95cm SPD and 2.8293 cm2 EAP. Saimiri sciureus pelvis is characterized as dolichopelvic. There was statistical significance between the values for adult females and subadults to SBID, BIAD, RDD, LDD, SPD and EAP. The values of SBID and IBID were lower when compared to the published data for the same species. The result found on this paper will serve as a basis for future studies using pelvic measurements and dystocia prediction of neotropical primates and comparison between different vivaria.(AU)

Saimiri sciureus é uma espécie de primata neotropical muito utilizada como animal de pesquisa. No entanto ainda há dificuldades em biotérios quanto a sua reprodução devido à alta ocorrência de distocia. A distocia em primatas pode ter origem devido à desproporção cefalopélvica, sendo que em macacos-de-cheiro é relatada a gestação de fetos grandes. O presente trabalho descreve dados de pelvimetria em espécimes de macaco-de-cheiro, fêmeas adultas e subadultas provenientes de uma colônia de pesquisa do Pará, Brasil. Foram realizadas radiografias da pelve em projeção ventrodorsal e por meio destas mensurados os diâmetros biilíaco superior (DBIS); diâmetro biíliaco inferior (DBII); diâmetro biilíaco médio (DBIM); diâmetro diagonal direito (DDD); diâmetro diagonal esquerdo (DDE); diâmetro sacro-púbico (DSP); com base nos diâmetros obtidos também foi calculada a área de entrada da pelve (AEP). Os valores médios dos diâmetros pélvicos e da AEP em fêmeas adultas foram: DBIS 1,714cm, DBIM 1,957cm, DBII 1,686cm, DDD 2,771cm, DDE 2,764cm, DSP 2,543cm e AEP 3,9056cm2; e para fêmeas subadultas: 1,588cm DBIS, 1,850cm DBIM, 1,625cm DBII, 2,50cm DDD, 2,474cm DDE, 1,95cm DSP e 2,8293 cm2 AEP. Observou-se que a pelve de Saimiri sciureus é dolicopélvica. Houve diferença estatística significativa entre os valores para fêmeas adultas e subadultas para DBIS, DBIM, DDD, DDE, DSP e AEP. Em comparação com dados da literatura de pelvimetria para S. sciureus observaram-se menores valores de DBIS e DBII. O resultado deste trabalho servirá como base para futuros estudos utilizando-se mensurações pélvicas e predição de distocia em primatas neotropicais e referência para comparação entre S. sciureus de diferentes biotérios.(AU)

[Relation between pelvis malposition and functional knee pain by long distance running]. / Zusammenhang zwischen einseitiger Beckenfehlstellung und funktionell bedingten Knieschmerzen am Beispiel des Langstreckenlaufs.

PURPOSE: During endurance run knee problems often appear. This study wants to show the connection between a one- sided malposition of the pelvis and knee joint pain during endurance running. METHOD: We tested endurance runners which had pelvis malposition and knee pain. Therefore 100 athletes were tested, 50 with knee pain and 50 without knee pain. Manual examination and clinical instruments were used for examination of sacroiliac joints for measurement of vertical distances between spinae iliacae anteriores superiores. Collected data were analyzed by appropriate statistical methods. RESULTS: The results show that there is a connection between a one- sided pelvic malposition and knee pain during endurance running. These relations are probably realized by changes in lower extremity dysfunction as a result of pathological chains. The one sided pelvis malposition was in the control group significant higher (0.9 ± 0.4 cm) than in the control group (0.3 ± 0.2 cm). CONCLUSION: There is a correlation between knee pain and os coxae malposition. (It is necessary in examine and treat the the cause- and effect chain to prevent injuries).