Biomedical subjects

A M Pappas

Publications and source records attributed to A M Pappas.

At least 19 recordsLinked to original sources

PubMed1998

Shoulder and elbow injuries and painful syndromes.

Childhood participation in organized sports has led to increased incidence of orthopedic complaints in the pediatric and adolescent populations, and year-round participation in a single sport allows no rest period from muscle use, bone development, and maturation. What effect do these factors have on the musculoskeletal system of the young athlete? They may lead to injuries such as dislocations, fractures, and problems of bone growth. This comprehensive review of shoulder and elbow anatomy and mechanisms of injury includes specific recommendations for rehabilitation.

Adolescent↗

PubMed1996

Pitcher's arm: an electrodiagnostic enigma.

Every major league baseball pitcher, most minor league pitchers, but only few amateur pitchers that we have studied have had reduced sensory nerve action potentials in the throwing arm. We present 6 clinical cases which demonstrate the spectrum of "pitcher's arm." These cases suggest that the phenomenon is a pathologic process, probably an example of a repetitive use syndrome affecting the brachial plexus. Although it does not appear to impact performance, it has clear implications for the interpretation of electrodiagnostic studies in symptomatic pitchers.

Action Potentials↗

PubMed1992

CT and MR evaluation of the labral capsular ligamentous complex of the shoulder.

Stability of the glenohumeral articulation is dependent on the integrity of the rotator cuff, labrum, glenohumeral ligaments, capsular elements, and bony glenoid. The importance of the soft-tissue elements in maintaining stability has been well documented in the surgical literature but has only recently been introduced into the radiologic literature. The purpose of this essay is to illustrate the normal labrum, capsular complex, and glenohumeral ligaments, including common congenital variations as depicted by CT arthrography and MR imaging, and to describe the pathologic findings leading to shoulder instability.

Humans↗

PubMed1990

Axillary artery compression and thrombosis in throwing athletes.

A 28-year-old major league baseball pitcher sustained an axillary artery thrombosis which was successfully treated with intraarterial urokinase. Subsequent angiography and duplex scanning with the arm elevated in the pitching position demonstrated inducible compression of the axillary artery by the humeral head as well as compression at the thoracic outlet. To determine the incidence of axillary and subclavian artery compression and to investigate the mechanism of injury, brachial artery blood pressures and duplex scans of the subclavian and axillary arteries were performed in both the neutral position and the throwing position in the 92 extremities of 19 major league baseball pitchers, 16 non-pitching major league players, and 11 nonathlete controls. A drop in blood pressure of greater than 20 mm Hg was noted in the position in 56% of extremities tested, with a loss of a detectable blood pressure in 13%. Compression of the axillary artery by the humeral head was documented in 83% of extremities, but in only 7.6% was a greater than 50% stenosis inducible. No statistical difference was found in the incidence of arterial compression between the three groups tested or between their dominant and nondominant extremities. Dissection of the axillary artery in two cadavers documented that abduction and external rotation of the arm causes compression of the axillary artery by the humeral head, which acts as a fulcrum. We conclude that the repetitive mechanical trauma of the throwing motion can cause intermittent compression and contusion of the axillary artery by the humeral head and predisposes the athlete who throws to thrombosis of the axillary artery.

Adult↗

PubMed1984

In vivo strain patterns in the four major canine knee ligaments.

Using mercury gauges, we measured strains in vivo in the four major ligaments of the canine knee joint as the tibia was loaded in valgus or varus at fixed angles of knee flexion. Free axial rotation of the tibia on the femur was allowed. Forces up to 78.4 N were applied to the tibia, producing moments of approximately 9 N-m. We found that with valgus loading, significant strains were observed in the medial collateral ligament at extension. At 45 degrees of flexion, the medial collateral, posterior cruciate, and anterior cruciate were strained. At 90 degrees of flexion, all four ligaments were strained. With varus loading, significant strains were found in the lateral collateral and anterior cruciate at extension. The lateral collateral and anterior cruciate ligaments were strained at 45 degrees of flexion. At 90 degrees of flexion, the lateral collateral, anterior cruciate, and posterior cruciate ligaments were strained. With valgus loading, the tibia rotated internally and the degree of axial rotation increased with flexion. External rotation of the tibia resulted from varus loading, and was relatively constant through the range of flexion. Thus when axial rotation is allowed, stability of the knee in response to valgus and varus loads is maintained by the cruciates as well as the collaterals, and the role of the cruciates increases with flexion and axial rotation.

Animals↗

PubMed1984

Axillary arthrotomography of the glenoid labrum.

In a study of 67 shoulders evaluated by axillary arthrotomography, tears of the glenoid labrum were accurately detected in all 26 surgically confirmed cases. One false-positive case was identified in the five patients without labral tears; there were no false-negative cases. Only 40% of the patients had clinical evidence of subluxation or dislocation. Axillary arthrotomography provides important information about the integrity of the labrum that may be helpful in planning surgery for patients with anatomic instability. Its greatest utility seems to be in those patients without clinical subluxation or dislocation but with pain, clicking, or vague shoulder discomfort secondary to labral pathology (functional instability). In these patients, the arthrotomogram forms the basis for surgical intervention.

Axilla↗

PubMed1984

Asymmetrical arrest of the proximal tibial physis and genu recurvatum deformity.

We are reporting six cases of premature asymmetrical closure of the proximal tibial physis and associated genu recurvatum deformity and have reviewed the fourteen cases reported in the English-language literature. No single etiological factor could be implicated as the cause of the physeal arrest. Trauma, prolonged immobilization, tibial wire traction, and a surgical procedure involving the proximal tibial physis were observed risk factors among our patients. In our patients, established genu recurvatum due to deformity of the proximal end of the tibia and associated tibial length discrepancy were managed successfully by an opening-wedge osteotomy through the proximal one-third of the tibia and bone-grafting. Epiphyseodesis in the contralateral extremity may be required in patients with significant shortening of the tibia.

Adolescent↗

PubMed1984

Congenital posteromedial bowing of the tibia and fibula.

Patterns of growth and development are presented for 33 patients with congenital posteromedial bowing of the tibia and fibula. The bowing is accompanied by shortening of the tibia and fibula, an initial calcaneovalgus deformity of the foot, and a decrease in ankle motion that does not improve with age. In general, the greater the initial bowing, the greater the ultimate extremity length discrepancy. The proportionate length differences between the normal and the bowed tibiae remained stable after the age of 12 months. This allowed a projection of anticipated extremity length discrepancy at maturity and a determination of the proper treatment. At birth the bowing varied from approximately 25 to 70 degrees, and at maturity the absolute tibial length discrepancies varied from 3.3 to 6.9 cm. Both the posterior and the medial components of the bow became markedly reduced with increasing age, but a mild residual medial portion of the bow remained. Soft tissue enlargement was observed in the posterior aspect of the affected legs in early life and developed to a relative muscle atrophy in later years.

Child↗

PubMed1984

Acquired valgus deformity of the tibia in children.

Nine cases of acquired valgus deformity following injury to the proximal tibial metaphysis in children are presented. The deformity is of a dual nature, involving both angular deformity and longitudinal overgrowth. The angular component reaches a maximum within 2 years after the injury. There is some indication that the angular component will remain static or spontaneously correct if treated nonoperatively. Treatment intervention in the majority of the cases has precluded an analysis of the natural history of the longitudinal overgrowth. Early intervention in the form of corrective osteotomy during the growth years has resulted in an unacceptably high rate of recurrence of both components of the deformity. Nonoperative treatment seems to be the treatment of choice for the angular component of valgus deformity following proximal tibial fracture in children. Significant longitudinal overgrowth may be corrected with appropriately timed epiphysiodeses calculated from observed growth rates and skeletal maturational patterns.

Child↗

PubMed1983

Congenital abnormalities of the femur and related lower extremity malformations: classification and treatment.

Congenital abnormalities of the femur vary from a deficiency of the entire femur with abnormal development of the pelvis to a hypoplastic femur of normal configuration. Previous classification systems that have focused on either congenital coxa vara, hypoplastic femur, or proximal femoral focal deficiency provide a limited definition of congenital abnormalities and are included within the combined classification system outlined in this text. This system, based on embryological, teratological, biological, and anatomical considerations of 125 patients with 139 affected femora, classifies deficiencies of the proximal end, middle, and distal end of the femur and associated lower extremity abnormalities. Unlike previous classification systems, congenital femoral abnormalities principally involving the middle and distal end of the femur are recognized in distinct classes when appropriate. Associated abnormalities range from severe growth retardation of the tibia and an absent fibula accompanied by a deficiency of ischiopubic structures with an absent acetabulum to a mild tibial and fibular growth retardation. Treatment objectives include pelvic-femoral stability, prosthetic management, extremity length equality, knee stability, ankle and foot stability, and anatomical alignment.

Ankle↗

PubMed1982