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Biomedical subjects

J Fronek

Publications and source records attributed to J Fronek.

10 recordsLinked to original sources
PubMed2001

In vivo changes after mechanical injury.

Chondrocytes undergo apoptosis in response to mechanical injury in vitro. The current clinical study correlates arthroscopic and magnetic resonance imaging results with biopsy specimens of cartilage from patients with knee injury. Twenty patients were evaluated at a mean 2.7 months after acute knee injury. The mean age of the patients was 32 years and the mean weight was 83 kg. Cartilage lesions were graded separately on magnetic resonance images and arthroscopy in a blinded manner. During arthroscopy, a 1.8 mm diameter biopsy specimen was obtained from the edge of cartilage lesion. The biopsy specimen underwent histologic examination by safranin O staining and detection of chondrocyte apoptosis by the presence of deoxyribonucleic acid fragmentation. There was a positive correlation in 50% (10 of 20) when the presence or absence of cartilage lesions by magnetic resonance imaging was correlated with arthroscopy. All cases of partial thickness or full-thickness cartilage loss that were seen by arthroscopy also were detected by magnetic resonance images. Apoptotic cells were significantly more numerous in biopsy specimens from lesions compared with control biopsy specimens. The findings of reduced cell viability attributable to apoptosis may have profound implications for cartilage repair. This opens potential therapeutic avenues for the treatment of posttraumatic cartilage lesions through apoptosis prevention.

Adult↗
PubMed1998

Exertional compartment syndrome of the upper extremity.

Exertional compartment syndrome is characterized by intracompartmental pressures that rise transiently following repetitive motion or exercise, thereby producing temporary, reversible ischemia, pain, weakness, and, occasionally, neurologic deficits. The exact cause or pathogenesis remains unclear; a disturbance of microvascular flow caused by elevated intramuscular pressure leads to tissue ischemia, depletion of high-energy phosphate stores, and cellular acidosis. Anatomic contributing factors may include a limited compartment size, increased intracompartmental volume, constricted fascia, loss of compartment elasticity, poor venous return, or increased muscle bulk. The diagnosis is suspected based on history and confirmed with physical examination and intramuscular pressure evaluation before and after exercise (stress test). Differential diagnosis includes claudication or other vascular abnormalities, myositis, tendinitis, periostitis, chronic strains or sprains, stress fracture, other compression or systemic neuropathies, and cardiac abnormalities with angina or referred extremity pain. Initial treatment includes activity modification; refractory symptoms can be managed with elective fasciotomy.

Chronic Disease↗
PubMed1989

Posterior subluxation of the glenohumeral joint.

Twenty-four patients who had posterior subluxation of the glenohumeral joint were assigned to one of two groups on the basis of the severity of the symptoms. The sixteen patients in Group I, who had less severe symptoms, were treated with a physical therapy program that was based on exercises to strengthen muscles. The eleven patients in Group II (three of whom had no success with physical therapy when they were originally in Group I) had a posterior capsulorrhaphy, with or without a bone block. According to an over-all rating, Group I had a rate of success of 63 per cent, and Group II had a rate of success of 91 per cent. The patients who had more severe ligamentous laxity were not more likely to fail either of the treatment programs. Although voluntary subluxation may be a subtle but important indicator of underlying emotional difficulties, it appears that, in the patient who is emotionally stable, the ability to voluntarily subluxate the shoulder posteriorly is not associated with a negative prognosis for either non-surgical or surgical treatment. Patients who have moderately disabling posterior subluxation of the shoulder should be treated with an intensive program that is designed to strengthen muscles. Patients who have symptoms that are severely disabling or who have had no success with non-operative treatment should be treated with posterior capsulorrhaphy. When the posterior aspect of the glenoid is severely deficient and when the posterior portion of the capsule or the infraspinatus tendon is attenuated, a bone block should augment the reconstruction.

Adolescent↗
PubMed1988

Disruption of the lateral capsule of the shoulder. A cause of recurrent dislocation.

Experimental work has shown that dislocation of the shoulder may involve disruption of the capsule from its lateral humeral attachment. We report two patients with recurrent dislocation due to this injury. Lateral repair gave good results. It is suggested that this injury be considered and looked for when glenoid labral injury is minimal or absent.

Adult↗
PubMed1987

Posterior shoulder instability.

The incidence, basic pathophysiology, and clinical and radiologic examination in posterior instability of the shoulder are discussed. Conservative treatment protocols and surgical procedures are presented.

Humans↗
PubMed1987

Management of chronic exertional anterior compartment syndrome of the lower extremity.

Eighteen patients (28 compartments) with chronic exertional compartment syndrome and 14 normal asymptomatic volunteers (18 compartments) were studied. Evaluation included clinical assessment followed by quantitative determination of intracompartmental pressures as monitored by wick or slit catheters before and after exercise. Intramuscular pressures measuring greater than or equal to 10 mmHg at rest and/or greater than or equal to 25 mmHg five minutes after exercise were defined as abnormally elevated. The patients with chronic compartment syndrome described reproducible exertional anterolateral leg pain, and 39% of these patients had a fascial hernia. Such a defect was present in less than five percent of the normal volunteers. Nonsurgical treatment was selected by five patients and all five reported persistent inability to participate in athletics because of their exertional pain. Of the remaining 13 patients, 12 were treated by decompressive fasciotomy and 11 of the 12 (92%) had pain relief and increased exercise tolerance. A single patient had had fascial closure instead of fasciotomy, and this procedure produced an acute compartment syndrome. Effective treatment of the chronic compartment syndrome consists of reduction of exertional activities or surgical decompression by fasciotomy.

Adolescent↗
PubMed1984

Tendons and ligaments: a morphological and biochemical comparison.

The purpose of this study was to compare selected rabbit tendons and ligaments morphologically and biochemically. Five representative structures from each of six age- and sex-matched rabbits were compared. Biochemical analyses included total collagen, reducible collagen cross-links, quantitative collagen typing, DNA, and glycosaminoglycans. Histological and chemical differences were demonstrated between the tendons and the ligaments. Smaller differences were also found between the individual ligaments (collateral and cruciate) and between the two tendons (patellar and Achilles) that were examined. These findings suggest that ligaments are more metabolically active than tendons, having more plump cellular nuclei, higher DNA content, larger amounts of reducible cross-links, and the presence of more type III collagen, as compared with tendons. They also contain slightly less total collagen than tendons and more glycosaminoglycans. We conclude that the tendons and ligaments studied have unique histological and biochemical characteristics, despite their gross similarities. Relatively increased metabolic activity in ligaments, implied by our findings, may be species specific, age related (transient), or may truly represent a structural expression of functional need for more rapid adaptation. Further investigation of other similarities or differences between particular ligaments (or tendons) is indicated, and attention is directed toward the importance of such variables in development of models for tendon and ligament studies.

Animals↗
PubMedDate not supplied

Intra-articular pressure determination during glenohumeral joint arthrography. Preliminary investigation.

Utilizing cadaveric and patient shoulders, normal values of intra-articular pressure were established during injection of increasing volumes of fluid within the glenohumeral joint. The characteristic biphasic pressures vs. volume curve that was normally observed was then compared with curves obtained in patients with a tear of the rotator cuff or with adhesive capsulitis. This method of examination should allow accurate objective assessment of the presence and severity of adhesive capsulitis.

Humans↗
PubMedDate not supplied

The Bennett lesion of the shoulder.

In this article we review the imaging features and significance of the Bennett lesion of the shoulder. Standard radiographic, computed arthrotomographic, and MR findings in three baseball pitchers diagnosed with Bennett lesions of the shoulder are discussed. A crescent-shaped region of mineralization at the posteroinferior aspect of the glenoid rim, consistent with a Bennett lesion, arises at the insertion of the posterior joint capsule. The diagnosis of this lesion, typically in baseball pitchers, should raise suspicion for associated labral and rotator cuff abnormalities.

Adult↗