Patellofemoral joint kinematics in individuals with and without patellofemoral pain syndrome.

BACKGROUND: Patellofemoral pain syndrome is a prevalent condition in young people. While it is widely believed that abnormal patellar tracking plays a role in the development of patellofemoral pain syndrome, this link has not been established. The purpose of this cross-sectional case-control study was to test the hypothesis that patterns of patellar spin, tilt, and lateral translation make it possible to distinguish individuals with patellofemoral pain syndrome and clinical evidence of patellar malalignment from those with patellofemoral pain syndrome and no clinical evidence of malalignment and from individuals with no knee problems. METHODS: Three-dimensional patellofemoral joint kinematics in one knee of each of sixty volunteers (twenty in each group described above) were assessed with use of a new, validated magnetic resonance imaging-based method. Static low-resolution scans of the loaded knee were acquired at five different angles of knee flexion (ranging between -4 degrees and 60 degrees). High-resolution geometric models of the patella, femur, and tibia and associated coordinate axes were registered to the bone positions on the low-resolution scans to determine the patellar motion as a function of knee flexion angle. Hierarchical modeling was used to identify group differences in patterns of patellar spin, tilt, and lateral translation. RESULTS: No differences in the overall pattern of patellar motion were observed among groups (p>0.08 for all global maximum likelihood ratio tests). Features of patellar spin and tilt patterns varied greatly between subjects across all three groups, and no significant group differences were detected. At 19 degrees of knee flexion, the patellae in the group with patellofemoral pain and clinical evidence of malalignment were positioned an average of 2.25 mm more laterally than the patellae in the control group, and this difference was marginally significant (p=0.049). Other features of the pattern of lateral translation did not differ, and large overlaps in values were observed across all groups. CONCLUSIONS: It cannot be determined from our cross-sectional study whether the more lateral position of the patella in the group with clinical evidence of malalignment preceded or followed the onset of symptoms. It is clear from the data that an individual with patellofemoral pain syndrome cannot be distinguished from a control subject by examining patterns of spin, tilt, or lateral translation of the patella, even when clinical evidence of mechanical abnormality was observed.

Magnetic resonance imaging for in vivo assessment of three-dimensional patellar tracking.

We have developed a non-invasive measurement technique which can ultimately be used to quantify three-dimensional patellar kinematics of human subjects for a range of static positions of loaded flexion and assessed its accuracy. Knee models obtained by segmenting and reconstructing one high-resolution scan of the knee were registered to bone outlines obtained by segmenting fast, low-resolution scans of the knee in static loaded flexion. We compared patellar tracking measurements made using the new method to measurements made using Roentgen stereophotogrammetric analysis in three cadaver knee specimens loaded through a range of flexion in a test rig. The error in patellar spin and tilt measurements was less than 1.02 degrees and the error in lateral patellar shift was 0.88 mm. Sagittal plane scans provided more accurate final measurements of patellar spin and tilt, whereas axial plane scans provided more accurate measurements of lateral translation and patellar flexion. Halving the number of slices did not increase measurement error significantly, which suggests that scan times can be reduced without reducing accuracy significantly. The method is particularly useful for multiple measurements on the same subject because the high-resolution bone-models need only be created once; thus, the potential variability in coordinate axes assignment and model segmentation during subsequent measurements is removed.

Accurate assessment of patellar tracking using fiducial and intensity-based fluoroscopic techniques.

Accuracies of a point-based and an intensity-based fluoroscopic methods of assessing patella tracking were determined by comparing the pattern of patellar motion with respect to orientation (flexion, internal rotation, and lateral tilt) and translation (lateral, proximal, and anterior) with the pattern of patellar motion measured using Roentgen stereophotogrammetric analysis in three cadaver knee specimens. Each pose in the patellar motion could be obtained from single as well as multiple calibrated fluoroscopic images. The errors using the intensity-based method were slightly higher than those of the point-based method, but they appear to be sufficiently low to detect clinically significant differences in patellar kinematics.

Diagnosis of gastroesophageal reflux in pediatrics.

Gastroesophageal reflux (GER) may be normal, functional, or pathogenic. Normal GER is of short duration and seen in all individuals. Functional GER, or effortless regurgitation, is common during infancy, causing no ill effects. Pathogenic GER causes diseases such as failure-to-thrive, coughing, choking, aspiration, apnea and/or bradycardia, esophagitis with irritability and excessive crying. Clinically it becomes imperative to distinguish normal and functional from pathogenic GER. The tests presently employed to detect GER are roentgenogram of the upper gastrointestinal tract (showing barium GER), scintigraphy of the esophagus after ingestion of a 99mTc labeled meal (indicating meal GER) and prolonged pH probe monitoring the lower esophagus (depicting acid GER). There seems to be a controversy regarding the usefulness of these tests for the diagnosis of pathogenic GER. In the present study of 89 infants and children presenting with signs and symptoms of pathogenic GER, 70% had significant acid GER, while 36% and 17% had barium and meal GER respectively. No statistically significant correlations were detected between acid GER, barium GER, and meal GER. We conclude that these three tests probably represent different phenomena, and that prolonged esophageal pH monitoring should be considered the most reliable and gold standard for detection of pathogenic GER.

Michel's anomaly, type I microtia and microdontia.

Michel's anomaly is an extremely rare cause of congenital sensorineural hearing loss. We present a 2-1/2 year old white female with this inner ear defect associated with type I microtia and microdontia. Assessment of anatomic structures of the ear is critical in an infant with abnormal auditory brainstem responses to determine whether a structural lesion is present and the most appropriate rehabilitative approach available.

Radiographic findings in early onset neonatal group b streptococcal septicemia.

Chest roentgenograms obtained in the first two days of life from 67 infants with respiratory distress were reviewed to determine whether the radiographic features of group B streptococcal septicemia were diagnostic or distinctive. The retrospective review contained 24 infants with proven and 14 with suspected septicemia, as well as 29 patients with other causes of respiratory distress. The films were reviewed in random order by two pediatric radiologists without their prior knowledge of clinical or laboratory data. Typical radiographic appearance of pneumonia was present in only ten of the 24 proven and two of the 14 suspected cases of group B streptococcal sepsis. The radiographic pattern of respiratory distress syndrome (RDS) was just as common among these patients. The most prominent associated radiographic feature of infants with proven septicemia was cardiomegaly which was significantly increased when compared with infants who had other causes of respiratory distress (P less than .001). X-ray recognition of neonatal group B streptococcal septicemia is limited because of superimposition of roentgen patterns probably related to associated disorders. Pediatrics, 59:1006-1011, 1977, NEWBRON, SEPTICEMIA, GROUP B STREPTOCOCCUS.

The course of the cerebrocostomandibular syndrome.

Three children with the cerebrocostomandibular syndrome have been studied. They were from unrelated families. The sib of one of them may demonstrate partial expression of a disorder that varies in severity, so that long-term survival is possible. Long-term survival may be complicated by restrictive pulmonanry disease and cardiac failure. A disorder of cellular growth may account for the symptoms.

Possible adverse effect of methylglucamine diatrizoate compounds on the bowel of newborn infants with meconium ileus.

Gastrografin (methylglucamine diatrizoate) enemas were carried out in 2 newborn infants with meconium ileus. Evacuation was slow and incomplete. Both patients died within 72 hours following enemas from bowel necrosis, perforation and peritonitis. Although it is not possible to implicate Gastrografin directly as the cause, it is suggested that it may have contributed substantially to bowel necrosis. Recent experimental evidence of colonic inflammation and occasionally necrosis caused by Gastrografin lends support to this hypothesis. Caution should be exercised to prevent not only the systemic osmotic effects of Gastrografin, but also potential local injury to the bowel, especially when underlying disease interferes with intestinal viability.

Congenital absence of the ductus venosus: with direct connection between the umbilical vein and the distal inferior vena cava.

Umbilical vessel catheterization in a neonate with Noonan's syndrome disclosed a unique developmental anomaly of the umbilical vein. There was no evidence of a ductus venosus nor any connection between the vein and the portal hepatic venous system. The umbilical vein instead entered the inferior vena cava directly at the level of the iliac veins. There was a single umbilical artery.

Duodenojejunal atresia with "apple-peel" small bowel. A distinct form of intestinal atresia.

Prenatal occlusion of the superior mesenteric artery results in a distinct type of distal duodenal or proximal jejunal atresia in which the dorsal mesentery is absent and the distal small bowel assumes a spiral configuration around its vascular stalk, strongly resembling an apple peel. In some instances the condition is transmitted genetically as an autosomal recessive disorder. The mortality rate is much higher than in either simple duodenal or jejunal atresia because of deficient collateral circulation to the small intestine. The authors tell of 2 patients who died of necrotizing enterocolitis, a disease related to vascular insufficiency.

Radiologic features of "adult type" polycystic kidney disease in the neonate.

Two cases are reported of adult type polycystic renal disease (autosomal dominant) presenting in the newborn as a unilateral abdominal mass. The radiographic findings in the involved kidney simulated the ectatic tubules of infantile polycystic disease, yet histologic examination was consistent with the adult variety and both infants had other family members with adult type polycystic kidneys. These cases emphasize some of the ambiguities that exist in the definition and classification of polycystic renal disease.

The distended gastric fundus: simulation of a left suprarenal mass.

A discrete region of low or absent activity in the left suprarenal area, simulating an avascular mass on renal imaging or radionuclide angiography, can result from dilatation of the gastric fundus.

Barium enema findings in type I hepatorenal glycogen storage disease.

Four children with Type I hepatorenal glycogen storage have been studied by barium enema. All showed strikingly similar changes of a smooth-walled, slightly narrow but normal length colon without any haustration. The findings simulated colitis but the patients had either mild diarrhea or no gastrointestinal complaints. Small bowel series was normal. Endoscopy and biopsy failed to provide an adequate explanation, there being no evidence of glycogen storage in the biopsy material and the degree of colitis in two patients who were endoscoped was minimal. The explanation for these radiographic findings is not known at present, although they have similarities to the "cathartic colon syndrome" described in adults.