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Biomedical subjects

J R Davids

Publications and source records attributed to J R Davids.

At least 19 recordsLinked to original sources
PubMed2000

Clinical evaluation of bowed legs in children.

Early radiographic screening and/or referral to a clinical specialist are often used to distinguish between physiologic bow leg deformity and infantile tibia vara disease in young children. These practices are a consequence of the clinician's inability (based upon the clinical examination) to distinguish between the deformities associated with physiologic and pathologic bow legs. Because the great majority of these children have physiologic bowing, routine radiographic screening and referral are not cost effective and expose children to unnecessary radiation. This study describes and evaluates the efficacy of a simple clinical examination technique, the 'cover up' test, to identify young children with bow legs who are at high risk for having infantile tibia vara. The 'cover up' test qualitatively assesses the alignment of the proximal portion of the shank or lower leg relative to the thigh or upper leg. Obvious valgus alignment is considered a negative test and is indicative of physiologic bowing. Neutral or varus alignment is considered a positive test and suggests that the child is at greater risk for having infantile tibia vara. Eighteen children with infantile tibia vara, evaluated initially prior to 3 years of age, and followed to the time of surgical correction, were compared with 50 children with physiologic bowing, also evaluated initially prior to 3 years of age and followed to resolution (mean follow-up 3 years and 10 months). All of the children with infantile tibia vara had a positive 'cover up' test (sensitivity = 1.00). Eighteen of 25 children with a positive 'cover up' test actually had or developed infantile tibia vara (positive predictive value = 0.72). Forty-three of 50 children with physiologic bowing had a negative 'cover up' test (specificity = 0.86). All of the children with a negative 'cover up' test actually had physiologic bowing (negative predictive value = 1.00). We conclude that the 'cover up' test is an effective screening tool for the assessment of bow legs in children between 1 and 3 years of age. Children with a negative 'cover up' test do not require radiographic evaluation and should be followed clinically for resolution of the bowing. Children with a positive 'cover up' test should have radiographic evaluation of the lower extremities or be referred to a specialist for further evaluation and treatment.

Bone Diseases, Developmental↗
PubMed2000

A biomechanical analysis of gait during pregnancy.

BACKGROUND: There are many anatomical changes during pregnancy that could potentially lead to substantial alterations in gait. Gait deviations may contribute to a variety of musculoskeletal overuse conditions associated with pregnancy, such as low-back, hip, and calf pain. Because we are aware of little research on this topic, the purpose of this study was to objectively analyze gait during pregnancy. METHODS: Three-dimensional gait analysis was performed on fifteen women during the second half of the last trimester of pregnancy and again one year post partum. Selected kinematic and kinetic parameters for the pregnancy and one-year postpartum conditions were compared with use of paired t tests (95 percent significance level). RESULTS: Overall, gait kinematics were remarkably unchanged during pregnancy. No evidence of a so-called waddling gait during pregnancy was found. Maximum anterior pelvic tilt during gait increased a mean of 4 degrees during pregnancy, although individual subject-to-subject variation (range, an increase of 13 degrees to a decrease of 10 degrees) was observed. Significant increases in hip and ankle kinetic gait parameters, however, were observed during pregnancy (p < 0.05). CONCLUSIONS: Significant increases in kinetic gait parameters during pregnancy (p < 0.05) explain how gait motion remained relatively unchanged despite increases in body mass and width as well as changes in mass distribution about the trunk. This finding indicates that during pregnancy there may be an increased demand placed on hip abductor, hip extensor, and ankle plantar flexor muscles during walking.

Adult↗
PubMed1999

Cubitus varus associated with dislocation of both the medial portion of the triceps and the ulnar nerve.

Five patients with cubitus varus deformities from malunited childhood fractures had dislocation (snapping) of both the medial portion of the triceps and the ulnar nerve over the medial epicondyle. In addition to snapping, these patients had medial elbow pain or ulnar nerve symptoms. Cubitus varus shifts the line of pull of the triceps more medial, which can cause anteromedial displacement of the medial portion of the triceps during elbow flexion. The ulnar nerve is concomitantly pushed or pulled anteromedially by the triceps, and ulnar neuropathy may result from friction neuritis or from dynamic compression by the triceps against the epicondyle. Recognition of both the dislocating ulnar nerve and the snapping medial triceps is crucial in the successful treatment of this pathologic finding. In symptomatic individuals, we recommend either corrective valgus osteotomy of the distal humerus or partial excision or lateral transposition of the snapping medial triceps, or a combination of both. Alternatively, medial epicondylectomy can also eliminate the snapping. Transposition of the ulnar nerve can be performed for ulnar nerve symptoms and/or ulnar nerve instability. Using this approach, correction of the snapping and/or ulnar nerve symptoms was achieved in all cases.

Adolescent↗
PubMed1999

A survey of function in children with lower limb deficiencies.

Function and prosthesis technical problems were surveyed in 258 experienced paediatric lower-limb prosthesis wearers. The two-part survey form consisted of the modified Prosthesis Evaluation Scale and the core module of the American Academy of Orthopaedic Surgeons/Council of Musculoskeletal Specialty Societies (AAOS/COMSS) Lower Limb Outcomes instrument. Eighty-eight percent (88%) of these paediatric subjects were able to wear their prosthesis more than 9 hours/day; only 3 subjects (1%) were not able to wear their limb at all. The average distance walked per day was reported to be 5.24 kilometres. Sixteen percent (16%) reported pain as "moderate" or worse. A majority reported not having a problem with perspiration, however, 20% had problems serious enough to limit prosthesis wearing time significantly. The most common reasons for temporary loss of limb use were pain (62 responses) and prosthesis failure (59 responses), followed by tissue breakdown (42 responses) and perspiration (30 responses). In general, the paediatric population achieves full use at a high rate, is much more active than the adult population, and experiences less limb pain.

Adolescent↗
PubMed1998

Kinematic and kinetic analysis of running in children with cerebral palsy.

Computer-based analysis of gait was used to study walking and running in 19 children with spastic-diplegic cerebral palsy (CP) and 15 healthy control children. Temporospatial parameters, kinematic and kinetic data were compared and contrasted between groups for both types of gait. The majority of children with diplegic CP, who are independent ambulators, are able to run. These children increase their velocity by increasing their cadence, a mechanism that is distinct (and presumably less energy efficient) from that used by healthy children. Sagittal-plane kinematic and kinetic profiles at the ankle in children with CP were more similar to normal profiles in running than in walking, suggesting that the primary deviations at the ankle associated with CP are better tolerated at greater velocities. Relative power analysis showed that, like healthy children, those with CP depend more upon the proximal musculature about the hip for power generation as the velocity of gait increases. Children with CP achieve energy transfer between adjacent joints during walking and running in a manner comparable to unaffected children. Running is an important activity for children and should be considered in the functional assessment of those with CP.

Cerebral Palsy↗
PubMed1997

Dislocating medial triceps and ulnar neuropathy in three generations of one family.

Variations in the medial triceps in conjunction with bilateral ulnar neuropathy have been identified in three generations of one family also possessing the phenotype of Waardenburg syndrome (a rare autosomal-dominant disorder with clinical features including cochlear deafness, dystopia canthorum, and pigmentation problems). To our knowledge, no other inherited condition with triceps anomalies has been reported. Study of this family provided insight into the relationship between dislocating medial triceps and ulnar neuropathy and demonstrated that a broad spectrum of clinical presentations exists-from being completely asymptomatic to producing symptomatic snapping and ulnar neuropathy.

Adolescent↗
PubMed1997

Skin surface pressure beneath an above-the-knee cast: plaster casts compared with fiberglass casts.

Complications related to immobilization in a cast after an injury or an operation may be related to the materials used for the cast or to the techniques of application, or to both. To evaluate the widely held clinical opinion that the use of a fiberglass cast is dangerous and inappropriate when subsequent swelling of the extremity is anticipated, we studied the skin surface pressures that were generated beneath above-the-knee casts made with different materials and applied with different techniques. A prosthetic model of the lower extremity was designed with an expandable calf compartment to simulate swelling after an injury or an operation. With use of this model, we measured the skin surface pressure beneath a plaster-of-Paris cast, a fiberglass cast that had been applied with a standard technique, and a fiberglass cast that had been applied with a stretch-relax technique. The highest mean skin surface pressure after application of the cast (p < 0.001) and after simulated swelling of the limb (p = 0.04) was generated by the fiberglass cast that had been applied with a standard technique. The lowest mean skin surface pressure after application of the cast (p = 0.006), simulated swelling of the limb (p < 0.001), and all subsequent steps of the experimental protocol (p < 0.001) was generated by the fiberglass cast that had been applied with the stretch-relax technique. The mean skin surface pressure generated by the plaster cast and by the fiberglass cast applied with the standard technique did not return to the value before application of the cast until anterior and posterior longitudinal cuts had been made in the cast and the cast had been spread at those cuts. When the fiber-glass cast had been applied with the stretch-relax technique, the mean pressure returned to the baseline value after only an anterior longitudinal cut and spreading at that cut. The principal pitfall of the use of a fiberglass cast is related to the technique of application. When the fiberglass cast had been applied with the standard technique, it generated a mean skin surface pressure that was higher than that associated with the plaster cast and it accommodated simulated swelling poorly. When the fiberglass cast had been properly applied, with the stretch-relax technique, it generated a mean skin surface pressure that was significantly lower (p = 0.006) than that associated with the plaster cast and it better accommodated simulated swelling without the need to sacrifice the structural integrity of the cast.

Calcium Sulfate↗
PubMed1996

Pediatric knee. Clinical assessment and common disorders.

Knee pain and injury are commonly seen in children and adolescents. A comprehensive evaluation of the knee is built on an appreciation of the anatomy, biomechanics, and pathophysiology of common disorders. This article considers these issues and describes a sequential technique for physical examination of the knee. Relevant imaging options and management strategies also are discussed.

Adolescent↗
PubMed1996

Longitudinal deficiency of the fibula. Operative treatment.

We reviewed the results of early amputation and prosthetic fitting in twenty-five children (thirty-one extremities) who had longitudinal deficiency of the fibula and were managed between 1977 and 1992. The median age at the time of the initial operation was thirteen months (range, eight months to nine years and eight months). The median duration of follow-up was eight years and ten months (range, two years and six months to sixteen years and eleven months). A Syme amputation was performed on fifteen extremities (thirteen children), and a modified Boyd amputation (which included resection of the distal tibial physis) was performed on sixteen extremities (thirteen children). (One child had a Syme amputation on one side and a Boyd amputation on the other and is thus included in both groups). In twenty-seven extremities, simultaneous excision of the fibular anlage was performed to prevent the development of a deformity secondary to the potential tethering effect. In twelve extremities, a diaphyseal osteotomy of the tibia also was performed to correct tibial bowing and to improve the mechanical alignment of the extremity. At the time of follow-up, the patients who had had a Syme amputation had more problems related to reformation of the calcaneus, instability of the heel pad, prosthetic suspension, and excessive length of the residual extremity. The modified Boyd amputation improved the function of the heel pad and the prosthetic suspension and provided the optimum length of the residual extremity. We also found that an early diaphyseal osteotomy of the tibia to correct severe bowing improved prosthetic fitting. This study did not support the concept that early resection of the fibular anlage or a diaphyseal osteotomy of the tibia prevents the development of hypoplasia of the lateral femoral condyle and associated genu valgum deformity.

Amputation, Surgical↗
PubMed1995

Operative treatment of bone overgrowth in children who have an acquired or congenital amputation.

Fifty-three children who were less than thirteen years old were followed for a median of seven years and ten months (range, two years and nine months to fourteen years and six months) after operative treatment for overgrowth of the tibia or humerus after amputation. During the thirty-one years in which these children were managed, three operative techniques were used in successive periods. Thus, the fifty-three children could be divided into three groups: thirty-one who had had a resection and revision, nine in whom the bone had been capped with a synthetic device, and thirteen in whom the bone had been capped with an autogenous tricortical bone graft from the iliac crest. A retrospective review was performed to determine the result and complications associated with each of these techniques. Survival analysis revealed that subsequent procedures were performed in twenty-six (84 per cent) of the thirty-one patients who had had a resection and revision, in seven of the nine in whom the bone had been capped with a synthetic device, and in four of the thirteen in whom the bone had been capped with an autogenous bone graft. The estimated mean survival time (that is, the time to a subsequent procedure) was five years in the group that had had the bone capped with an autogenous graft and three years and six months in the group that had had resection and revision; the difference is significant (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Rotational deformity and remodeling after fracture of the femur in children.

The remodeling potential of angular deformities in the coronal and sagittal planes in children is widely appreciated, and has been studied extensively. The short-term clinical consequences and remodeling potential of torsional deformity after fracture of the femur are less well understood. Computerized axial tomography (CT) was used to identify and follow children with torsional malunion after standard treatment (traction/spica cast) of a closed femur fracture. Seven fracture patients with torsional differences greater than 10 degrees were selected and observed. Computed axial tomography scans were performed at the time of spica cast removal and at the one-year follow-up examination. Four cases showed diminished femoral torsion (one case retroversion), and three cases showed increased femoral torsion. The deformity ranged from 13 degrees to 38 degrees. Follow-up CTs one year later showed no significant correction of deformity. Clinically, deformity of up to 25 degrees was well tolerated. The only symptomatic patient (38 degrees malunion) had a third CT done 28 months after injury, which showed no further correction of deformity. This study confirms the poor remodeling potential of significant posttraumatic torsional deformity of the femur in children.

Bone Malalignment↗
PubMed1993

Common gait abnormalities of the knee in cerebral palsy.

Gait abnormalities in children with cerebral palsy are the consequence of contractures across joints, muscle spasticity, and phasically inappropriate muscle action. Though abnormalities involving one of the major joints of the lower extremity will usually have consequences on the function of the other joints, it is possible to recognize certain primary disorders at each joint. The most common gait abnormalities of the knee in patients with cerebral palsy occur in the sagittal plane. Based on the experience gained from performing gait analysis on more than 588 patients with cerebral palsy, four primary gait abnormalities of the knee have been identified: jump knee, crouch knee, stiff knee, and recurvatum knee. In this review, each abnormality is described by its motion analysis laboratory profile (physical examination, motion parameters, electromyography [EMG] data, and force plate data). The most common etiologies and the consequences for gait of each disorder are also considered. Appreciation of the most common pathologic patterns of gait should facilitate accurate and detailed analysis of the individual patient with gait abnormalities.

Biomechanical Phenomena↗
PubMed1991

Fracture through the stalk of pedunculated osteochondromas. A report of three cases.

Although fracture through the base of an osteochondroma is a well-recognized clinical entity, the fate of such fractures has never been documented. Recommendations concerning the treatment of these fractures are contradictory. Of the three cases of fracture through the base of a pedunculated osteochondroma observed in the last 12 years, two healed without problem, one in a patient with a solitary osteochondroma, the other in a patient with multiple osteochondromas. The third patient remained symptomatic one year after injury, and histologic evaluation of the specimen after surgical excision confirmed the diagnosis of fibrous nonunion of the fracture. Experience with fractures through the base of a pedunculated osteochondroma suggests that the majority of these fractures will heal without complication, regardless of whether they involve solitary or multiple osteochondromas. However, symptomatic fibrous nonunion of such a fracture may occur particularly when an osteochondroma is located near large, mobile tendons.

Bone Neoplasms↗
PubMed1990

Orthopaedic aspects of fragile-X syndrome.

Fragile-X syndrome is one of the most common inherited forms of mental retardation. An associated connective-tissue disorder involving elastin accounts for the most frequent musculoskeletal manifestations, which include severe flexible flat feet, excessive laxity of the joints, and scoliosis. At our institution, seventy-five (50 per cent) of the 150 male patients who had fragile-X syndrome had flat feet, eighty-five (57 per cent) had excessive laxity of the joints, and ten had scoliosis. Twenty-nine of the patients who had flat feet had been evaluated or treated, or both, by an orthopaedic surgeon before the diagnosis of fragile-X syndrome had been made. Only one of these patients had been referred for developmental and genetic evaluation, which suggests that the orthopaedic community is not familiar with this syndrome. The orthopaedist should consider the diagnosis of fragile-X syndrome in the evaluation of a mentally retarded boy or man who has a family history of mental retardation. The presence of flat feet and excessive laxity of the joints, associated with the characteristic facies, macro-orchidism, and behavior, justifies a referral for developmental and genetic evaluation. Early diagnosis is important for several reasons, including genetic counseling for the family, more efficacious medical treatment, and specialized education.

Adolescent↗
PubMed1990

Luxatio erecta humeri. A case report.

Luxatio erecta humeri is a rare type of glenohumeral dislocation. The pathomechanics of this injury involve either direct axial loading on a fully abducted extremity or leverage of the humeral head across the acromion by a hyperabduction force. The clinical presentation of this type of shoulder dislocation is unique, with the affected extremity held rigidly above the head in abduction. Reduction is accomplished by a form of traction-countertraction under intravenous sedation and analgesia. A variety of neurologic and vascular injuries may be associated with luxatio erecta humeri, involving the brachial plexus and axillary artery, respectively. Concomitant fracture of the acromion, clavicle, coracoid, greater tuberosity, and humeral head may also be seen. A computed tomography scan of the case reviewed here revealed a large humeral head defect oriented perpendicular to the classic Hill-Sachs lesion. Luxatio erecta humeri is associated with significant late morbidity, including recurrent dislocation, instability, and adhesive capsulitis.

Adult↗