Search PubMed⌕ Search

Biomedical subjects

J M Fox

Publications and source records attributed to J M Fox.

At least 55 records · Page 3Linked to original sources
PubMed1992

Arthroscopic-assisted anterior cruciate ligament reconstruction with the semitendinosus tendon: comparison of results with and without braided polypropylene augmentation.

Fifteen chronic anterior cruciate ligament-deficient knees were arthroscopically reconstructed with a semitendinosus tendon polypropylene (STP) augmented composite graft. A comparison group of 28 reconstructions with the semitendinosus tendon (ST) but without augmentation was simultaneously reviewed. The mean follow-up in the STP group was 31 months (range of 24-42 months) and in the ST group it was 34 months (range 26-54 months). Both patient groups had similar age, sex, preinjury functional sports level, injury-to-surgery interval, and associated meniscal pathology. Good-to-excellent subjective results were reported in 86% of STP patients and 78% of ST patients, whereas 86% of the STP patients and 88% of the ST patients returned to sports activity. Objective examination revealed 73% of the STP group and 82% of the ST group to have a negative or 1+ Lachman test result. A negative pivot shift was noted at follow-up in 80% of the STP group and in 82% of the ST group. KT-1000 testing revealed 60% of the STP patients and 61% of the ST patients to have less than or equal to 3 mm of side-to-side difference. In the STP group there was no evidence of graft breakage, deep infections, or sterile effusions. Overall subjective and functional results were uniformly better than objective results in both patient groups. Analysis of subjective, objective, and functional results reveal no difference in outcome between the STP and the ST patient groups.

Adult↗
PubMed1992

Neural responses to visual texture patterns in middle temporal area of the macaque monkey.

1. We studied how neurons in the middle temporal visual area (MT) of anesthetized macaque monkeys responded to textured and nontextured visual stimuli. Stimuli contained a central rectangular "figure" that was either uniform in luminance or consisted of an array of oriented line segments. The figure moved at constant velocity in one of four orthogonal directions. The region surrounding the figure was either uniform in luminance or contained a texture array (whose elements were identical or orthogonal in orientation to those of the figure), and it either was stationary or moved along with the figure. 2. A textured figure moving across a stationary textured background ("texture bar" stimulus) often elicited vigorous neural responses, but, on average, the responses to texture bars were significantly smaller than to solid (uniform luminance) bars. 3. Many cells showed direction selectivity that was similar for both texture bars and solid bars. However, on average, the direction selectivity measured when texture bars were used was significantly smaller than that for solid bars, and many cells lost significant direction selectivity altogether. The reduction in direction selectivity for texture bars generally reflected a combination of decreased responsiveness in the preferred direction and increased responsiveness in the null (opposite to preferred) direction. 4. Responses to a texture bar in the absence of a texture background ("texture bar alone") were very similar to the responses to solid bars both in the magnitude of response and in the degree of direction selectivity. Conversely, adding a static texture surround to a moving solid bar reduced direction selectivity on average without a reduction in response magnitude. These results indicate that the static surround is largely responsible for the differences in direction selectivity for texture bars versus solid bars. 5. In the majority of MT cells studied, responses to a moving texture bar were largely independent of whether the elements in the bar were of the same orientation as the background elements or of the orthogonal orientation. Thus, for the class of stimuli we used, orientation contrast does not markedly affect the responses of MT neurons to moving texture patterns. 6. The optimum figure length and the shapes of the length tuning curves determined with the use of solid bars and texture bars differed significantly in most of the cells examined. Thus neurons in MT are not simply selective for a particular figure shape independent of whatever cues are used to delineate the figure.

Animals↗
PubMed1992

The postoperative knee.

Magnetic resonance (MR) has established itself as the gold standard for noninvasive imaging of the knee. As in arthroscopy, assessment of injuries to the menisci, articular surfaces, synovium, and cruciate ligaments can be made. Additionally, MR has an advantage over arthroscopy in being able to assess the para articular soft tissues and cortical and medullary bony compartments. Until recently, the role of MR in the postoperative knee has been less clear. New information, however, suggests that MR is capable of assessing the status of the partially resected meniscus, the adjacent articular surfaces, and subchondral medullary lesions that frequently occur. There has been recent interest in reestablishment of the stabilizing function of a previously torn anterior cruciate ligament by means of autogenous or allogenous materials. MR permits the surgeon to assess the isometry and possible sites of graft impingement that may occur following cruciate ligament reconstruction. The purpose of this article is to define the current status of MR in the assessment of the postoperative knee.

Bone Transplantation↗
PubMed1991

The anaesthetic management of a patient with a phaeochromocytoma and acute stroke.

A case is reported of a young woman in whom the diagnosis of a phaeochromocytoma was made after a major stroke. Preoperative preparation included the introduction of phenoxybenzamine, 10 mg.day-1, and propranolol, 80 mg.day-1, over a two-week period. The presence of cerebrovascular disease and the marked orthostatic changes in blood pressure and heart rate to low-dose phenoxybenzamine prevented the establishment of full alpha blockade. Incomplete alpha blockade probably contributed to the hypertensive response to manipulation of the tumour (220/150 mmHg) and hypotension occurred after removal of the tumour (80/45 mmHg). An anaesthetic technique was chosen to provide haemodynamic stability as well as protection against cerebral ischaemia. Invasive haemodynamic monitoring, a four-channel processed electroencephalograph and somatosensory evoked potentials were used to accomplish these goals.

Adrenal Gland Neoplasms↗
PubMed1991

Osteonecrosis of the knee after arthroscopic surgery: diagnosis with MR imaging.

Spontaneous osteonecrosis about the knee typically is a disease of the elderly characterized by an acute onset of pain. The exact cause of this condition has long been debated, although a causative relationship between meniscal tears and spontaneous osteonecrosis about the knee has been postulated. Seven patients with knee pain, meniscal tears, and chondromalacia without initial evidence of osteonecrosis at magnetic resonance (MR) imaging underwent arthroscopic surgery with meniscal recontouring or repair and cartilage shaving. These patients returned within 2-14 months with recurrent pain in the treated knee. MR imaging then demonstrated abnormalities consistent with osteonecrosis. Osteonecrosis of the femoral condyle or tibial plateau may be a late sequela of meniscal injury in association with chondromalacia and arthroscopic surgery. This diagnosis should be suspected in patients with recurrent knee pain after arthroscopic repair of meniscal tears. The precise relationship of this pattern of osteonecrosis to that previously described as spontaneous requires further investigation.

Arthroscopy↗
PubMed1991

Accuracy of diagnoses from magnetic resonance imaging of the knee. A multi-center analysis of one thousand and fourteen patients.

Magnetic resonance images of the knee were made for 1014 patients, and the diagnosis was subsequently confirmed arthroscopically. The accuracy of the diagnoses from the imaging was 89 per cent for the medial meniscus, 88 per cent for the lateral meniscus, 93 per cent for the anterior cruciate ligament, and 99 per cent for the posterior cruciate ligament. The magnetic resonance examinations were done at several centers, and the results varied substantially among centers. The accuracy ranged from 64 to 95 per cent for the medial meniscus, from 83 to 94 per cent for the lateral meniscus, and from 78 to 97 per cent for the anterior cruciate ligament. The results from different magnetic-resonance units were also compared, and the findings suggested increased accuracy for the units that had a stronger magnetic field. Of the menisci for which the magnetic resonance signal was reported to be Grade II (a linear intrameniscal signal not extending to the superior or inferior meniscal surface), 17 per cent were found to be torn at arthroscopy.

Adolescent↗
PubMed1990

Evaluation of patients with persistent symptoms after lateral retinacular release by kinematic magnetic resonance imaging of the patellofemoral joint.

The arthroscopic lateral retinacular release is typically performed to treat patellar pain and instability. This procedure was previously considered to be relatively benign with a low associated complication rate. However, a high incidence of medial subluxation of the patella was recently reported in patients with persistent symptoms after lateral retinacular release. Because the use of physical examination criteria may not always be sufficient to assess patellar alignment, 40 patients (43 knees) were evaluated by the newly developed technique of kinematic magnetic resonance imaging of the patellofemoral joint. One (2%) patellofemoral joint had normal patellar alignment, 10 (23%) had lateral subluxation of the patella, 1 (2%) had excessive lateral pressure syndrome, 27 (63%) had medial subluxation of the patella, and 4 (9%) had lateral-to-medial subluxation of the patella. Seventeen of 40 patients (43%) with unilateral arthroscopic lateral retinacular releases had medially subluxated patellae on the unoperated joints. Because patellar malalignment commonly affects bilateral joints, medial subluxation of the patella may have been present before the lateral retinacular release but was not recognized in these patients.

Adult↗
PubMed1990

A psychogeriatric nursing assessment protocol for use in multidisciplinary practice.

The assessment of geriatric patients with psychiatric or neurobehavioral problems demands a multidisciplinary approach linking nursing, psychiatry, neurology, geriatrics, and internal medicine. While the medical disciplines have relatively well-established approaches to assessing psychogeriatric patients, nursing lacks a comprehensive assessment strategy that supports both nursing and multidisciplinary practice. This article describes the Psychogeriatric Nursing Assessment Protocol (Abraham, 1989) developed for use in a multidisciplinary geriatric neuropsychiatric outpatient clinic. The relationship of the protocol to psychiatric, neurological, geriatric, and medical assessments is discussed in an attempt to clarify the linkages of knowledge and care required for successful service delivery to geriatric patients with psychiatric or neurobehavioral problems, as well as to their families and formal and informal caregivers.

Activities of Daily Living↗
PubMed1990

Peripheral meniscal tears: MR findings after conservative treatment or arthroscopic repair.

Follow-up knee magnetic resonance (MR) examinations were performed on 17 patients (18 menisci) with arthroscopically proved tears of the outer third of the meniscus who were treated either conservatively (six patients) or with surgical repair (11 patients). All patients satisfied accepted clinical orthopedic criteria for meniscal healing. MR examinations obtained 3-27 months after injury revealed persistent signal intensity (grade 3), unchanged from that seen on the preoperative study, in all 15 patients in whom both pre- and postoperative studies were obtained and in three of four menisci that were proved to be healed at second-look arthroscopy. It appears that grade 3 signal from both conservatively treated and repaired menisci may persist long after the tear has become asymptomatic and has presumably healed. The presence of such signal should not be interpreted as necessarily indicating meniscal retear in these patients. Persistent signal intensity at the site of previous injuries may account for some reported cases of disagreement between MR and arthroscopic findings.

Adolescent↗
PubMed1990

Results of arthroscopic meniscectomy.

It would appear that arthroscopic partial menisectomy offers as good, if not better, results compared with open meniscectomy. Authors who have compared patients undergoing open meniscectomy with those undergoing arthroscopic meniscectomy have also shown that the other variables and parameters so important to the patient in the early postoperative period weight very heavily in favor of arthroscopic meniscectomy.

Arthroscopy↗
PubMed1990

Acute anterior cruciate ligament reconstruction. Analysis of complications.

One hundred fifty-six patients treated with intraarticular anterior cruciate ligament (ACL) reconstruction were analyzed to determine the incidence of complications. The study group of 31 patients (Group I) was treated with repair or reconstruction of an acute ACL injury. A comparison group of 125 patients had reconstruction for chronic ACL instability (Group II). The patients were evaluated clinically and by roentgenograms. The average follow-up time for the study group was 52.2 months. In Group I, 35% developed fibroarthrosis postoperatively that required arthroscopic lysis of adhesions and manipulation to restore motion. In Group II, only 12% developed this complication. However, developing this complication did not affect a patient's long-term clinical result when properly recognized and promptly treated.

Adolescent↗
PubMed1989

Patellar tracking abnormalities: clinical experience with kinematic MR imaging in 130 patients.

A kinematic magnetic resonance (MR) imaging technique for assessment of malalignment of the patella, involving the acquisition of multiple sequential axial images of the patellofemoral joint during the early increments of passive knee flexion, was used to evaluate 130 patients (235 symptomatic patellofemoral joints) showing clinical evidence of having patellar tracking abnormalities. Twenty-three of the patellofemoral joints had undergone previous surgical procedures for patellar realignment. In addition, 14 (28 patellofemoral joints) asymptomatic control subjects were studied. Normal patellar tracking was observed in all of the asymptomatic subjects and in 43 (17%) of the 260 patellofemoral joints in the patient population, 18 (7%) of which were symptomatic. Sixty-nine (26%) of the patellofemoral joints had lateral subluxation of the patella, 106 (41%) had medial subluxation of the patella, 21 (8%) had excessive lateral pressure syndrome, 19 (7%) had lateral-to-medial subluxation of the patella, and two (1%) had dislocation of the patella. Of the 235 patellofemoral joints with suspected abnormalities, 217 (93%) had patellar malalignment. Of the 23 patellofemoral joints that had undergone prior surgery, 20 (87%) had abnormal patellar tracking. Thirteen of 14 (93%) patellofemoral joints that had undergone a prior arthroscopic lateral retinacular release had a medially displaced patella.

Adult↗
PubMed1989

Intraarticular versus intraarticular and extraarticular reconstruction for chronic anterior cruciate ligament instability.

One hundred twenty-seven patients were evaluated for the results of surgical stabilization in chronic anterior cruciate ligament instability. Eighty-four patients had been treated with intraarticular reconstruction alone, while 43 patients had been treated with a combination of intraarticular and extraarticular stabilization. Patients were evaluated by questionnaire to assess subjective and functional status by clinical examination of objective findings, and by roentgenograms and instrumented ligamentous stability testing. The follow-up interval averaged 45.2 months for the entire group (range, 24-90 months). Using a 200-point scale, the rating for the group treated with intraarticular reconstruction alone was 169.1, while the average rating for the group treated with combined intraarticular and extraarticular stabilization was 166.2. Overall, an excellent or good result was obtained in 67% of patients in the intraarticular only group and in 70% of the patients in the combined reconstruction group. There were no significant differences between the two groups in terms of changes seen on roentgenograms or in terms of residual laxity measured by instrumented testing. Thus, there is no demonstrable benefit derived from combined intraarticular and extraarticular stabilization procedures for chronic anterior cruciate ligament instability, provided that a well-placed intraarticular substitute of sufficient strength is functional.

Adolescent↗
PubMed1988

Oral flecainide pharmacokinetics in patients with impaired renal function.

The pharmacokinetics of flecainide acetate were studied in 20 patients with varying degrees of renal impairment following a single oral dose. The patients were divided into two groups, on the basis of renal creatinine clearance (CLCR), for statistical and kinetic analysis. Patients with a CLCR between 4 and 41 mL/min/m2 were designated group 1 and those below 4 mL/min/m2 or unmeasurable because of lack of urine output were designated group 2. In both groups peak plasma flecainide concentrations, time to peak concentrations, and apparent volume of distribution (Vd) were similar to those reported in healthy subjects with normal renal function. The mean flecainide plasma elimination half-lives from both groups 1 and 2 were longer than those previously reported by several investigators in normal subjects. Nine patients in group 1 and seven patients in group 2 had half-lives within the range reported in healthy subjects. Therefore, CLCR alone is not a good predictor of plasma elimination half-life following a single oral dose of flecainide. Although renal clearance of flecainide is significantly reduced in end-stage renal disease (ESRD), total plasma clearance of flecainide (CLflec) was not reduced to the same degree, although there was a significant, modest correlation with CLCR. Less than 1% of the administered oral dose of flecainide was removed during hemodialysis. The relationship between dosage and plasma elimination half-life in patients with ESRD needs further study to evaluate possible dose-dependent kinetics.

Administration, Oral↗
PubMed1988

Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities.

The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.

Adult↗
PubMed1988

Reconstruction of the anterior cruciate ligament using a torn meniscus.

In eighty of 100 patients, reconstruction of the anterior cruciate ligament using a torn meniscus was successful in restoring stability. The length of follow-up ranged from two to six years and the mean interval from injury to operation was two years. Preoperatively, all but one patient had a positive (2+ or 3+) Lachman test and a positive pivot-shift test. Only ten patients had evidence of major instability, as seen on either test. The result was the same regardless of whether the patient had had a concomitant extra-articular (Ellison) procedure. The results of arthroscopic biopsy in eleven patients did not support the hypothesis that the meniscus underwent metaplasia to ligamentous tissue. Although this procedure yielded results similar to those of other procedures in which autogenous tissues are used to reconstruct the ligament, the meniscus should rarely, if ever, be used for reconstruction of the anterior cruciate ligament. The procedure is indicated only for patients who, in addition to needing reconstruction of the anterior cruciate ligament, also have a torn meniscus that would otherwise have to be totally excised.

Adolescent↗