PubMed Health⌕ Search

Biomedical subjects

A A Allen

Publications and source records attributed to A A Allen.

At least 19 recordsLinked to original sources
PubMed2005

In vivo healing after capsular plication in an ovine shoulder model.

Traditionally, arthroscopic management of shoulder instability has been reserved for patients with isolated Bankart lesions without any capsular laxity or injury. To date, there are no animal studies evaluating the healing potential of capsular plication and/or capsulo-labral repair. The purpose of this in vivo animal study was to determine if the histological capsular healing of an open capsular plication simulating an arthroscopic plication is equivalent to the more traditional open capsular shift involving cutting and advancing the capsule. Twenty-six skeletally mature sheep were randomized to either an open capsular plication simulating arthroscopic plication (n = 13), or an open traditional capsular shift (n = 13). A sham operation (n = 4) was also performed involving exposure to visualize the capsule. Normal non-operated control shoulders were also analyzed. A pathologist blinded to the treatment evaluated both hematoxylin and eosin (H&E) sections and polarized light microscopy. Qualitative scoring evaluated fibrosis, mucinous degeneration, fat necrosis, granuloma formation, vascularity, inflammatory infiltrate and hemosiderin (0 to 3 points). Both the capsular plication and open shift groups demonstrated healing by fibrosis at the site of surgical manipulation. There were no statistical differences in the capsular healing responses between the two groups with regard to fibrosis, granuloma formation and vascularity. The open shift group demonstrated significantly more mucinous degeneration (p = 0.038). Fat necrosis was present in 4/13 specimens in the open shift group and none in the capsular plication specimens. Both groups demonstrated disorganized collagen formation under polarized light microscopy. There were no differences between non-operated control specimens and sham surgery specimens. Our findings support the hypothesis that histologic capsular healing is equivalent between the plication group and the open shift group. In addition, the open shift group demonstrated significantly more changes indicative of tissue injury. This basic science model confirms capsular healing after simulated arthroscopic plication, providing support for arthroscopic capsular plication in practice.

Animals↗
PubMed2003

Methylcellulose gel is a superior contrast agent for ultrasound examination of the cervix in obstetric patients.

OBJECTIVE: To determine the superior contrast agent for cervical sonography: water-soluble methylcellulose gel vs. normal saline. METHODS: Women with an indication for cervical sonography underwent placement of 10 mL water-soluble methylcellulose gel or normal saline. Assessment of cervical dimensions and contour was performed via transperineal sonography prior to and after contrast placement. RESULTS: Twenty-five patients with similar demographic characteristics and indications for ultrasonography were enrolled into each group. Administration of contrast improved the ability to visualize the external os or vaginal fornices in 18 women in the gel group vs. six in the saline group (P = 0.002). In the gel group, 17 patients had easier identification of the external os and visualization of the fornices was enhanced in 13 patients. The assessment of cervical length prior to and after contrast administration was not statistically different with the use of either of these agents. CONCLUSION: Intravaginal soluble gel is superior to normal saline as a cervical contrast agent. Intravaginal contrast may allow for easier identification of cervical anatomy during ultrasonographic examination in selected patients.

Adult↗
PubMed2001

Prenatal diagnosis and outcome of a ruptured aneurysm arising from the left atrium.

Prenatal diagnosis of a fetal cardiac aneurysm or diverticula is rare. We report what we believe to be the first case of an atrial wall aneurysm diagnosed as ruptured or leaking by fetal pericardiocentesis. Spontaneous resolution of the anomaly was observed in the third trimester with delivery of a vigorous newborn at term. The infant did not require surgical intervention after birth and has done well at follow-up examinations.

Adult↗
PubMed2001

Reliability, validity, and responsiveness of four knee outcome scales for athletic patients.

BACKGROUND: Many patient-based knee-rating scales are available for the evaluation of athletic patients. However, there is little information on the measurement properties of these instruments and therefore no evidence to support the use of one questionnaire rather than another. The goal of the present study was to determine the reliability, validity, and responsiveness of four knee-rating scales commonly used for the evaluation of athletic patients: the Lysholm scale, the subjective components of the Cincinnati knee-rating system, the American Academy of Orthopaedic Surgeons sports knee-rating scale, and the Activities of Daily Living scale of the Knee Outcome Survey. METHODS: All patients in the study had a disorder of the knee and were active in sports (a Tegner score of 4 points). Forty-one patients who had a knee disorder that had stabilized and who were not receiving treatment were administered all four questionnaires at baseline and again at a mean of 5.2 days (range, two to fourteen days) later to test reliability. Forty-two patients were administered the scales at baseline and at a minimum of three months after treatment to test responsiveness. The responses of 133 patients at baseline were studied to test construct validity. RESULTS: The reliability was high for all scales, with the intraclass correlation coefficient ranging from 0.88 to 0.95. As for construct validity, the correlations among the knee scales ranged from 0.70 to 0.85 and those between the knee scales and the physical component scale of the Short Form-36 (SF-36) and the patient and clinician severity ratings ranged from 0.59 to 0.77. Responsiveness, measured with the standardized response mean, ranged from 0.8 for the Cincinnati knee-rating system to 1.1 for the Activities of Daily Living scale. CONCLUSIONS: All four scales satisfied our criteria for reliability, validity, and responsiveness, and all are acceptable for use in clinical research.

Adolescent↗
PubMed2001

Arthroscopic bankart repair: experience with an absorbable, transfixing implant.

The use of arthroscopic means to address shoulder instability has provided a technically advantageous way to approach Bankart lesions while posing complex questions regarding the specific indications for such an intervention. A successful outcome with arthroscopic Bankart repair is a function of proper surgical indication and patient selection. Several authors have evaluated the causes of failure and reasons for success with the Suretac device. The development of a bioabsorbable repair device at the authors' institution was precipitated by a desire to address and repair Bankart lesions arthroscopically while avoiding the frequent complications associated with the metal staple and the transglenoid suture technique. The Suretac represents the first generation of bioabsorbable transfixing devices. The initial objectives of the Suretac device were to adequately and dynamically tension soft tissue to bone, while providing a bioabsorption profile that mirrored the native healing response. The Suretac device is an appropriate surgical tool for arthroscopically repairing Bankart lesions in a carefully selected patient population.

Absorbable Implants↗
PubMed1999

Proprioception in the posterior cruciate ligament deficient knee.

This study was undertaken to evaluate knee proprioception in patients with isolated unilateral posterior cruciate ligament (PCL) injuries. Eighteen subjects with isolated PCL tears were studied 1-234 months after injury. The threshold to detect passive motion (TTDPM) was used to evaluate kinesthesia and the ability to passively reproduce passive positioning (RPP) to test joint position sense. Two starting positions were tested in all knees: 45 degrees (middle range) and 110 degrees (end range) to evaluate knee proprioception when the PCL is under different amounts of tension. TTDPM and RPP were tested as the knee moved into flexion and extension from both starting positions. A statistically significant reduction in TTDPM was identified in PCL-injured knees tested from the 45 degrees starting position, moving into flexion and extension. RPP was statistically better in the PCL-deficient knee as tested from 110 degrees moving into flexion and extension. No difference was identified in the TTDPM starting at 110 degrees or in RPP with the presented angle at 45 degrees moving into flexion or extension. These subtle but statistically significant findings suggest that proprioceptive mechanoreceptors may play a clinical role in PCL-intact and PCL-deficient patients. Further, it appears that kinesthesia and joint position sense may function through different mechanisms.

Adult↗
PubMed1999

Intravaginal saline as a contrast agent for cervical sonography in the obstetric patient.

OBJECTIVE: To determine whether intravaginal saline alters visualization of the cervix during endovaginal sonographic examinations. DESIGN: A prospective trial with comparison of sonographic measurements of cervical length prior to and after administration of an intravaginal contrast agent. SUBJECTS: Patients with an indication for endovaginal ultrasonographic assessment of the cervix were considered as candidates for the study. METHODS: After assessment of cervical dimensions and contour of the internal cervical os, 10 ml of normal saline was placed intravaginally via a needleless syringe. Pre- and post-contrast sonographic examinations of the cervix were compared. RESULTS: Twenty-six patients were enrolled. No differences were observed in the identification of funnelling (37% in each group, p = 1.0) or the quantification of cervical length for the entire cohort (p = 0.95). However, in a subset of patients in whom the external os was not satisfactorily visualized (23%), intravaginal contrast resulted in a mean difference in cervical length pre- and post-saline infusion of 6.4 mm compared to 1.4 mm in patients in whom the external os could be easily identified (p < 0.001). No patient expressed undue discomfort related to the administration of contrast. CONCLUSION: Intravaginal saline assists in visualization of the cervix during endovaginal sonography for selected patients in whom precise identification of the external os is difficult.

Cervix Uteri↗
PubMed1998

Magnetic resonance imaging of articular cartilage in the knee. An evaluation with use of fast-spin-echo imaging.

The purpose of this study was to demonstrate that specialized magnetic resonance imaging provides an accurate assessment of lesions of the articular cartilage of the knee. Arthroscopy was used as the comparative standard. Eighty-eight patients who had an average age of thirty-eight years were evaluated with magnetic resonance imaging and subsequent arthroscopy because of a suspected meniscal or ligamentous injury. The magnetic resonance imaging was performed with a specialized sequence in the sagittal, coronal, and axial planes. Seven articular surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial plateaus) were graded prospectively on the magnetic resonance images by two independent readers with use of the 5-point classification system of Outerbridge, which was also used at arthroscopy. Six hundred and sixteen articular surfaces were assessed, and 248 lesions were identified at arthroscopy. Eighty-two surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep ulceration, fibrillation, or a flap without exposure of subchondral bone; and thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0 and 1 were regarded as disease-negative status and grades 2, 3, and 4 were regarded as disease-positive status. When the grades that had been assigned by reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent (144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the detection of a chondral lesion. Interobserver variability was minimum, as indicated by a weighted kappa statistic of 0.93 (almost perfect agreement). With use of this readily available modified magnetic resonance imaging sequence, it is possible to assess all articular surfaces of the knee accurately and thereby identify lesions that are amenable to arthroscopic treatment.

Adult↗
PubMed1997

Arthroscopic release of postoperative capsular contracture of the shoulder.

A loss of motion after an operation on the shoulder often cannot be treated successfully with physical therapy or closed manipulation. Although open release techniques generally improve motion, they involve extensive dissection. We developed a technique of arthroscopic capsular release and applied it in eighteen patients who had postoperative stiffness of the shoulder. The patients were selected for the arthroscopic release technique if a conservative program of physical therapy and an attempted closed manipulation had failed to restore motion and if they had no known extra-articular contractures. Five of the thirteen patients who had had a global loss of shoulder motion had motion restored with the anterior capsular release, and six needed an additional release of the posterior aspect of the capsule--that is, a combined (anterior and posterior) capsular release. The arthroscopic procedure could not be completed in the remaining two patients because of an extra-articular scar involving the subscapularis, but those patients were managed successfully with an open release. As five patients had lost only internal rotation and flexion, they had only a posterior capsular release. For the eleven patients who had had either an anterior or a combined (anterior and posterior) capsular release, the mean improvement in the score of Constant and Murley was 43 points (range, 31 to 62 points) and all improvements in motion were significant (p < 0.01). Flexion improved a mean of 51 degrees (range, 10 to 65 degrees); external rotation in adduction and abduction, 31 degrees (range, 10 to 50 degrees) and 40 degrees (range, 5 to 80 degrees), respectively; and internal rotation in adduction and abduction, six spinous-process levels (range, three to eleven levels) and 41 degrees (range, 20 to 70 degrees), respectively. For the five patients who had an isolated posterior capsular release, the score of Constant and Murley improved a mean of 20 points (range, 5 to 35 points) and the improvements in motion also were significant (p < 0.05 and 0.005). Internal rotation in adduction and abduction improved a mean of four spinous-process levels (range, one to ten levels) and 42 degrees (range, 30 to 60 degrees), respectively. Eight patients had an arthroscopic acromioplasty for concomitant impingement disease. One patient who had had a combined (anterior and posterior) release and one who had had a posterior capsular release continued to have pain because of injury of the articular cartilage from a previous operation. We concluded that arthroscopic capsular release is a reliable method for restoring motion with minimum morbidity in carefully selected patients who have postoperative stiffness of the shoulder. When necessary, it can be converted to an open release.

Adult↗
PubMed1997

Neurologic injury in the upper extremity after total hip arthroplasty.

The results of 7150 consecutive primary and revision total hip arthroplasties performed between 1976 and 1990 were reviewed retrospectively. Sixteen upper extremity neurologic palsies were identified in 16 patients. The incidence of upper extremity nerve palsies after total hip arthroplasty was 0.22%. There were five men and 11 women (average age, 59.5 years; range, 27-81 years). The neurologic injuries consisted of 10 ulnar palsies, four brachial plexopathies, one axillary nerve palsy, and one median nerve palsy. Patients were evaluated with respect to age, gender, preoperative diagnosis, type of procedure (primary versus revision), and surgical approach. Preoperative diagnoses included: inflammatory arthritis (11), osteoarthritis (two), avascular necrosis (one), developmental dysplasia of the hip (one), and posttraumatic arthritis (one). Fourteen of 16 patients (88%) had complete recovery. Two patients (12%) had persistent symptoms despite operative intervention. The only significant predisposing factor to developing an upper extremity neurologic injury after total hip arthroplasty was the preoperative diagnosis of an inflammatory arthropathy. Upper extremity neurologic injuries after total hip arthroplasty are rare. Patients with the preoperative diagnosis of an inflammatory arthropathy are at greater risk for experiencing upper extremity neurologic injury. The prognosis is favorable, with 88% of patients having complete recovery. Cautious induction of anesthesia and careful attention to patient positioning in the perioperative, intraoperative, and postoperative period are essential to help minimize the incidence of neurologic injuries in the upper extremity after total hip arthroplasty.

Adult↗
PubMed1996

Temperature changes in the knee joint during arthroscopic surgery.

Normal joint conditions are altered during arthroscopic surgery, and these changes have uncertain ultrastructural and biomechanical effects on articular cartilage. Experimental studies have shown that temperature variations affect the biomechanical properties of articular cartilage. We documented the temperature of the knee joint in 40 patients at the beginning and end of an arthroscopic procedure (anterior cruciate ligament reconstruction or meniscectomy). The intra-articular measurements were obtained using a digital thermometer connected to a sterile stainless steel probe. Correlation coefficients and linear regression techniques were used to determine which variables are independent predictors of joint temperature at the end of surgery. The mean knee joint temperature before surgery was 35.1 degrees +/- 1.0 degrees C and at the end of surgery 24.6 degrees +/- 1.5 degrees C. The joint temperature at the end of surgery was significantly affected by the temperature of the saline irrigant used and the length of arthroscopic procedure. The clinical implications of our findings must be clarified in animal models.

Adolescent↗
PubMed1995

Shoulder instability in the athlete.

Glenohumeral instability in the athlete represents a spectrum of disorders, which has been recognized and treated with increasing frequency. The first challenge for a clinician treating an athlete with shoulder instability is recognition and understanding of the instability pattern. The second challenge is to make the right therapeutic decision that will enable the athlete to return to his or her previous level of function with the shortest possible period of disability. Although most patients can be managed nonoperatively, arthroscopic and open stabilization are good options when these procedures are warranted.

Adolescent↗
PubMed1992

Use of blood glucose data by families of children and adolescents with IDDM.

OBJECTIVE: Prospective evaluation of the use of blood glucose test results for treatment actions by families of youth with IDDM. RESEARCH DESIGN AND METHODS: Forty-seven patients with IDDM used reflectance meters with memory for SMBG for 28 days. Parents kept weekly diaries of six types of uses of SMBG data. We collected SMBG data from the reflectance meters, HbA1 and serum fructosamine assays, and measures of behavioral factors that could affect use of SMBG data. RESULTS: Families recorded a mean of 4.85 data-based actions during the 28-day study, and 74% of the families reported at least one such action. Fifty percent of recorded actions consisted of management of hypoglycemia and, among the remainder, only 18% were anticipatory, proactive actions. Partial correlation analysis showed that families with more frequent use of SMBG data had less parent-child conflict about diabetes, more diabetes knowledge, and better overall treatment adherence. Use of SMBG data was unrelated to objective indices of the need for treatment adjustments or to diabetic control. CONCLUSIONS: Most families made active use of their SMBG data, but few of these actions were proactive. Behavioral factors were stronger predictors of family use of SMBG data than were objective indices of the need for treatment adjustments. The results illustrate the need for further research on use of SMBG data and methods to enhance its impact on diabetic control.

Adolescent↗
PubMed1992

Anatomy, histology, and vascularity of the glenoid labrum. An anatomical study.

We studied the gross, histological, and vascular anatomy of the glenoid labrum in twenty-three fresh-frozen shoulders from cadavera to demonstrate its cross-sectional anatomy, its microvascularity, and its attachments. The superior and anterosuperior portions of the labrum are loosely attached to the glenoid, and the macro-anatomy of those portions is similar to that of the meniscus of the knee. The superior portion of the labrum also consistently inserts directly into the biceps tendon, while its inferior portion is firmly attached to the glenoid rim and appears as a fibrous, immobile extension of the articular cartilage. The arteries supplying the periphery of the glenoid labrum come from the suprascapular, circumflex scapular, and posterior circumflex humeral arteries. In general, the superior and anterosuperior parts of the labrum have less vascularity than do the posterosuperior and inferior parts, and the vascularity is limited to the periphery of the labrum. Vessels supplying the labrum originate from either capsular or periosteal vessels and not from the underlying bone.

Adult↗
PubMedDate not supplied

Limb myokymia.

Thirty-eight patients with myokymic discharges localized to limb muscles on needle electromyography had various neurologic lesions, both acute and chronic. Of the 38 patients, 27 had had previous radiation therapy and the clinical diagnosis of radiation-induced plexopathy, myelopathy, or both. For the remaining 11 patients, the diagnoses included multiple sclerosis, inflammatory polyradiculoneuropathy, ischemic neuropathy, inflammatory myopathy, and chronic disorders of the spinal cord and peripheral nerves. The clinical presentations and results of local ischemia, peripheral nerve block, and percutaneous stimulation suggest that most limb myokymic discharges arise focally at the site of a chronic peripheral nerve lesion.

Adolescent↗
PubMedDate not supplied

Biologic fixation of ligament prostheses and augmentations. An evaluation of bone ingrowth in the dog.

The biologic fixation (bone ingrowth) of three prosthetic ligament devices (bovine xenograft Xenotech Laboratories, Inc., Irvine, CA; Gore-Tex, W. L. Gore and Associates, Flagstaff, AZ; and knitted dacron, Stryker, Kalamazoo, MI) and one ligament augmentation device (LAD, braided polypropylene, 3M, St. Paul, MN) were evaluated in vivo. The devices were placed unstressed, in an extraarticular location in the cortical-cancellous bone of the proximal femur and humerus of dogs. Six months following implantation tissue ingrowth was evaluated using high resolution radiography, routine histology, scanning electron microscopy, and biomechanical tensile tests to measure the ultimate (maximum) pull-out strength of the devices. The knitted dacron and Gore-Tex prosthesis showed marked ingrowth of trabecular bone into the interstices of the device with evidence of bone growth around individual fibers of the prosthesis. The bovine xenograft demonstrated bone immediately adjacent to the material with evidence of spicular ingrowth of bone into the natural clefts of the prosthesis. The LAD showed no evidence of bone ingrowth and demonstrated a fibrous tissue interface between the prosthesis and surrounding trabecular bone. Six months following implantation the pull-out strengths of the devices were as follows: knitted dacron, 445.7 +/- 151.0N; Gore-Tex, 438.1 +/- 131.94N; bovine xenograft, 332.8 +/- 64.2N; and LAD, 78.4 +/- 47.9N. Statistical analysis revealed no significant difference between the pull-out strengths of the knitted dacron, Gore-Tex, and bovine xenograft.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗