Shoulder after surgery: MR imaging with surgical validation.

To assess the accuracy of magnetic resonance (MR) imaging in the evaluation of the shoulder after surgery, MR examinations were performed in 31 patients before repeated surgery, and MR findings were correlated with the subsequent operative findings. In addition, the MR findings associated with prior surgery were reviewed, including altered structure of the acromion, soft-tissue metal artifacts, a surgical trough in the humeral head, nonvisualization of the subacromial-subdeltoid fat stripe, and intermediate signal intensity within the substance of the rotator cuff on images obtained with all pulse sequences. The MR criteria for full-thickness tears in the shoulder after surgery are the presence of fluidlike signal intensity on T2-weighted images that extends through an area of the rotator cuff or the nonvisualization of a portion of the rotator cuff.

Isokinetic and isometric measurement of strength of external rotation and abduction of the shoulder.

The strength of active external rotation and of abduction of the shoulder when the humerus was in the plane of the scapula (30 degrees of horizontal flexion anterior to the coronal plane) was measured isokinetically and isometrically in thirty-nine normal volunteers, who were stratified by age and sex. The angles at which peak torque was produced were similar when tested isokinetically and isometrically; these angles were similar for external rotation (at 60 and 30 degrees of internal rotation) and for abduction (at 30 and 60 degrees of abduction). Isometric peak torque was greater than slow-speed (90 degrees per second) isokinetic peak torque, which in turn was greater than fast-speed (210 degrees per second) isokinetic peak torque.

The inositol phosphate pathway as a mediator in the proliferative response of rat calvarial bone cells to cyclical biaxial mechanical strain.

Isolated newborn rat calvarial bone cells grown in monolayer on polyurethane membranes in specially constructed culture chambers and subjected to a cyclical biaxial mechanical strain of 0.17% at a frequency of 1 Hz for 30 min demonstrated a 16% increase in DNA synthesis during the subsequent 24 h. The metabolites of the inositol phosphate pathway, shown to be an important second messenger in many cell types, were shown to be elevated using high-performance liquid chromatography to separate and quantitate the various inositol polyphosphates.

The normal glenohumeral relationships. An anatomical study of one hundred and forty shoulders.

We measured the dimensions of the humeral and glenoid articular surfaces in 140 shoulders that were representative of a given population of patients, and also evaluated several glenohumeral relationships. Ninety-six measurements were made in the shoulders of cadavera and forty-four, on magnetic resonance-imaging studies of living patients. Eighty-five per cent of the humeral measurements fell within eight fixed combinations of the radius of curvature and the thickness of the humeral head, in two-millimeter increments.

Avulsion fracture of the supraglenoid tubercle: A variation of the SLAP lesion.

Tears of the anterior and posterior/superior labrum (SLAP) are often associated with overhead throwing sports. This lesion may be present in the absence of glenohumeral instability. Fracture of the supraglenoid tubercle associated with a SLAP lesion has not been previously reported.

Magnetic resonance imaging of the shoulder.

The authors have reviewed the field of magnetic resonance imaging of the shoulder. This review includes abnormalities of the rotator cuff mechanism and glenoid labrum, and other disorders.

The vascularity of the rotator cuff.

The major arterial supply to the rotator cuff is derived from the ascending branch of the anterior humeral circumflex artery, the acromial branch of the thoracoacromial artery, as well as the suprascapular and posterior humeral circumflex arteries. The pathogenesis of rotator cuff tears has been considered to be influenced by the microvascular supply of the rotator cuff tendons. Most cadaver studies have demonstrated a hypovascular area within the critical zone of the supraspinatus tendon.

Synthesis and characterization of magnetically responsive albumin microspheres containing cis-hydroxyproline for scar inhibition.

Magnetically responsive albumin microspheres containing the proline analog, cis-hydroxyproline, were synthesized and their in-vitro physical properties were characterized. These microspheres have an average size of 1.1 +/- 0.

Comparison of morphological and biochemical characteristics of cultured chondrocytes isolated from proliferative and hypertrophic zones of bovine growth plate cartilage.

Primary cultures of chondrocytes isolated from the proliferative and hypertrophic zones of bovine growth plate cartilage were established, and their morphological and biosynthetic characteristics were compared. High-cell-density monolayer cultures maintained a predominantly chondrocytic morphology, preserved their zone-specific collagen phenotype, and produced an abundant proteoglycan matrix. In contrast, monolayer cultures plated at low cell densities contained many cells with fibroblastic morphology and initiated the synthesis of type I collagen within 72 h following seeding.

Magnetic resonance imaging of the shoulder. Sensitivity, specificity, and predictive value.

The sensitivity, specificity, and predictive value of magnetic resonance imaging in the diagnosis of lesions of the rotator cuff, glenohumeral capsule, and glenoid labrum were evaluated in ninety-one patients and fifteen asymptomatic volunteers. Magnetic resonance imaging demonstrated 100 per cent sensitivity and 95 per cent specificity in the diagnosis of complete tears, and it consistently predicted the size of the tear of the rotator cuff. There was a definite correlation between atrophy of the supraspinatus muscle and the size of a complete, chronic tear of the rotator cuff.

Growth plate physiology and pathology.

The growth plate is made of cartilaginous, bony, and fibrous components, which act together to achieve longitudinal bone growth. The unique metabolism of the growth plate is a result of its unique microcirculation and extracellular microenvironment. The growth plate chondrocytes are responsive to both mechanical and hormonal stimuli, which can alter their normal function.

Mechanism of action of parathyroid hormone-induced proteoglycan synthesis in the growth plate chondrocyte.

In the growth plate chondrocyte, parathyroid hormone (PTH) stimulates phosphoinositol 4,5 bisphosphate (PIP2) degradation, which results in the rapid production of inositol (1,4,5) triphosphate (IP3). IP3 induced the release of calcium from an intracellular store, which caused a rapid increase in the cytosolic ionized calcium concentration. Parathyroid hormone also induced a 30-50% increase in proteoglycan synthesis.

Rotator cuff tears: diagnostic performance of MR imaging.

To determine the diagnostic performance of magnetic resonance (MR) imaging in the evaluation of suspected rotator cuff tears, eight asymptomatic volunteers and 32 patients with rotator cuff tendonopathy who underwent surgery were examined with MR imaging. Twenty-four of these patients also underwent contrast arthrography. The ability of MR imaging to depict the size of cuff tears and the quality of torn tendon edges was also evaluated.

Subcellular regulation of the ionized calcium pool in isolated growth-plate chondrocytes.

At a low total endogenous calcium content, as in the reserve and proliferative zone chondrocyte, cells buffer their ionized calcium pool at a low steady state between 150 and 300 nM. The endoplasmic reticulum appears to be primarily effective in the regulation of the ionized calcium pool under these conditions. With calcium loading of 20 to 30 nmol Ca+2/mg protein, as in the hypertrophic zone chondrocyte, the cells buffer their ionized calcium pool at a higher steady state between 600 and 700 nM.

Cytosolic ionized calcium concentration in isolated chondrocytes from each zone of the growth plate.

In isolated chondrocytes from the growth plate, there is an increase in both the cytosolic ionized calcium concentration and in total cell calcium content as the cells approach the mineralization front. The reserve zone chondrocytes have a cytosolic ionized calcium concentration, [Ca2+]i, of 124 +/- 23 nM and a total cell calcium content, CaT, of 12.8 +/- 6.

Treatment of the septic hip with total hip arthroplasty.

Forty-three patients, 23 with definite infection and 20 with probable infections before total hip arthroplasty (THA), were compared to 41 matched uninfected patients. The 43 infected patients were treated by 45 operative procedures: eight Girdlestone resections, 12 revisions of total hips, and 25 conversions from infected nontotal hip surgery to total hip arthroplasties. (Two revision THAs were converted to Girdlestones).

Cytosolic calcium concentration in bovine growth plate chondrocytes.

The cytosolic free calcium ion concentration for mammalian cell systems is believed to be maintained within a narrow range compatible with cellular homeostasis. Growth plate chondrocytes have been shown to accumulate large quantities of calcium within their mitochondria, but the cytosolic free calcium concentration has not been determined. This study measures the cytosolic free ionic calcium concentration in growth plate chondrocytes using two variations of the Quin II fluorescence technique.

Aseptic loosening after total hip arthroplasty. Incidence, clinical significance, and etiology.

Three hundred forty-one consecutive Charnley total hip arthroplasties were reviewed after a 3-10-year follow-up period to correlate the radiographic signs of aseptic loosening to clinical outcome, femoral cementing technique, and epidemiologic patient characteristics. High-grade femoral demarcation at the bone-cement interface (75-100%) correlated with a significantly higher incidence of unsatisfactory follow-up clinical scores. The incidence of high-grade femoral bone-cement demarcation and the associated radiographic signs of aseptic loosening had a direct correlation with the quality of the femoral cementing technique (P less than .

Calcium flux and endogenous calcium content in isolated mammalian growth-plate chondrocytes, hyaline-cartilage chondrocytes, and hepatocytes.

The role of chondrocyte mitochondria in endochondral ossification has been the subject of intensive investigation and controversy. The purpose of this study was to quantitate the endogenous calcium content and the maximum capacity for calcium accumulation and release in isolated mammalian growth-plate chondrocytes and hyaline-cartilage chondrocytes. The results indicated that the mitochondria of the isolated growth-plate and hyaline-cartilage chondrocytes possess a greater endogenous calcium content, a greater capacity for calcium accumulation, and a larger labile Ca+2 pool than do the mitochondria of hepatocytes.

Characterization of growth plate mitochondria.

The growth plate chondrocyte plays a central role in growth plate function. The purpose of this study was to characterize the respiratory and calcium transport properties of isolated mammalian growth plate chondrocytes and mitochondria obtained from these cells and to quantitate the mitochondrial weight and volume fraction in each zone of the growth plate. A new method was developed for isolation of mitochondria from chondrocyte suspensions.

Cellular swelling and irreversible myocardial injury. Effects of polyethylene glycol and mannitol in perfused rat hearts.

Irreversible injury was produced in Langendorf-perfused rat hearts by 60 minutes of hypoxic, substrate-free perfusion at 37 C. Upon reoxygenation, hearts suddenly released large amounts of creatine phosphokinase (CPK) and over 60% of cells contained contraction bands and appeared irreversibly injured by light and electron microscopic criteria. Ten percent polyethylene glycol (PEG) or mannitol (420 mOsmol/liter) prevented or reduced swelling of rat heart slices incubated in vitro in the cold or under anoxic conditions.