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Biomedical subjects

J S Keene

Publications and source records attributed to J S Keene.

At least 19 recordsLinked to original sources
PubMed1992

Signs of patellar chondromalacia on sagittal T2-weighted magnetic resonance imaging.

We incidentally noted distinctive high signal defects or fissures in the patellar articular cartilage on sagittal T2-weighted magnetic resonance (MR) images in 4 patients. At subsequent arthroscopy all 4 patients were found to have patellar chondromalacia. To determine the reliability of these signs, we retrospectively evaluated, in a blinded manner, sagittal T2-weighted MR images of the knee in 75 patients who were undergoing arthroscopic assessment of their patellar articular cartilage. We identified high signal defects or fissures in the patellar cartilage of 5 patients. Patellar chondromalacia was noted at arthroscopy in all 5 patients. Arthroscopy demonstrated patellar chondromalacia in an additional 21 patients with normal MR images. We conclude that high signal defects or fissures on sagittal T2-weighted images are useful signs of patellar chondromalacia. This single imaging sequence will, however, detect only a small number of the cartilage lesions that may be present.

Adolescent↗
PubMed1992

Iliac crest versus spinous process grafts in posttraumatic spinal fusions.

Results of posttraumatic spine fusions in 34 patients who had autogenous iliac crest grafts were compared with those of 70 patients who had autogenous spinous process grafts. The two groups of patients were otherwise homogenous, and fusion occurred in 32 (94%) of the iliac crest graft patients and 70 (100%) spinous process graft patients. However, average operative time (225 vs. 200 minutes) and operative blood loss (1371 vs. 1136 cc) were significantly higher in iliac crest graft patients (P less than 0.05), and five iliac crest graft patients had significant donor site complications. Use of spinous process grafts eliminated donor site problems, reduced operative time and blood loss, and produced a rate of arthrodesis equal to that of iliac crest grafts.

Adult↗
PubMed1991

Results of Harrington instrumentation in type A and type B burst fractures.

Comparisons of the reductions achieved with posterior Harrington instrumentation of 21 type A and 26 type B burst fractures revealed that the percent correction of angular deformity at surgery was significantly higher (type A, 52% versus type B, 65%) and was better maintained at 6 (type A, 13% versus type B, 36%) and 12 months (type A, 0% versus type B, 28%) after surgery in type B fractures (p less than 0.05). Percent correction of anterior compression achieved at surgery was similar for both groups (type A, 33% versus type B, 37%), but maintenance of correction 6 (type A, 9% versus type B, 23%) and 12 months after surgery (type A, 3% versus type B, 23%) also was significantly better in type B fractures (p less than 0.05). Percent correction of sagittal plane displacement immediately following surgery (type A, 71% versus type B, 73%), and 6 (type A, 62% versus type B, 61%) and 12 months after surgery (type A, 60% versus type B, 56%) was the same in both groups. Results of posterior instrumentation of burst fractures appears to be dependent upon the type of burst injury; significantly better reductions were achieved and maintained in Denis type B fractures.

Adolescent↗
PubMed1991

Unusual causes of back pain in athletes.

Typical causes of back pain in the athlete include muscle strain, intervertebral disc injury, interspinous bursitis, and spondylolysis. If initial evaluation does not indicate that any of these potential conditions is the cause, the physician or trainer should consider less common conditions. In this report, we discuss the identification and management of five unusual causes of back pain in the high school and college athlete: (a) disc space collapse after herniated disc excision, (b) sacralization of L5, (c) facet fracture of L5, (d) fracture of the lumbar vertebral apophysis, and (e) interosseous herniation of the lumbar disc.

Adolescent↗
PubMed1991

Improved postoperative course after spinous process segmental instrumentation of thoracolumbar fractures.

This article compares the postoperative course of 40 patients who had Harrington instrumentation with 40 patients who had Harrington instrumentation and interspinous process segmental instrumentation of unstable thoracolumbar fractures and reviews the findings. The two groups of patients were otherwise homogeneous, and average operative time, total blood loss, and days to oral intake were similar for both groups of patients. On average, however, patients undergoing interspinous process segmental instrumentation were out of bed sooner (4.5 versus 7.7 days, P less than 0.0001), discharged sooner (32 versus 38 days, P less than 0.079), and brace-free earlier (2.1 versus 5.9 months, P less than 0.001) and had fewer fixation-related complications than did patients undergoing Harrington instrumentation alone. Comparison of average hospital costs documented a savings of $5,160 for the typical patient undergoing interspinous process segmental instrumentation.

Adult↗
PubMed1990

Magnetic resonance imaging of muscle tears.

Magnetic resonance scans were obtained on 17 patients with acute, subacute, or chronic muscle tears. These patients presented with complaints of persistent pain or a palpable mass. Magnetic resonance findings were characterized according to alterations in muscle shape and the presence of abnormal high signal within the injured muscle. These areas of high signal were noted on both T1-weighted and T2-weighted scans and were presumed to represent areas of intramuscular hemorrhage.

Accidents, Traffic↗
PubMed1990

Anterior plating of unstable cervical spine fractures.

Medical records and radiographs of 16 patients who had anterior decompression, bone grafting, and plating of grade III and IV (Allen 1982) unstable cervical spine injuries were reviewed. Surgery was performed within 15 days of injury, reductions were achieved and maintained at follow-up, and fusion occurred in all cases. Neurologic function stabilised or improved in all cases. However, 3 patients (19%) had complications that necessitated additional surgery: one patient with undiagnosed non-contiguous posterior instability, and 2 patients for broken plates. These complications, in retrospect, could have been avoided.

Adolescent↗
PubMed1990

Results of hypotensive anesthesia in operative treatment of thoracolumbar fractures.

In a retrospective study of 109 patients who had Harrington instrumentation of thoracolumbar fractures, the results of normotensive anesthesia (75 patients) were compared with those of deliberate hypotensive anesthesia (34 patients). Estimated blood loss (EBL) and EBL per minute were significantly less (p less than 0.05) with hypotensive anesthesia. Neurological status of patients with incomplete or no deficits, monitored intraoperatively with either the Stagnara wake-up test (63 patients) or with somatosensory evoked potentials (23 patients), did not change during either the normotensive or hypotensive anesthesia. Deliberate hypotensive anesthesia is a safe and effective method for reducing blood loss during posttraumatic spinal stabilizations.

Adolescent↗
PubMed1989

Diagnosis of undetected knee injuries. Interpreting subtle clinical and radiologic findings.

The vast majority of knee problems can be diagnosed by taking a complete history, performing a comprehensive physical examination, and obtaining appropriate x-ray films. However, diagnosis of anterior and posterior cruciate ligament tears, patellofemoral subluxation, tibial tubercle fracture, and fibular head dislocation is challenging because they often present like common, less serious knee disorders. Accurate assessment of these five injuries depends upon the examiner's knowledge of the specific presenting complaints and the subtle clinical and radiologic findings associated with these conditions.

Adolescent↗
PubMed1989

Significance of acute posttraumatic bony encroachment of the neural canal.

Neurologic status (NS) of 80 consecutive patients with acute, traumatic thoracic, thoracolumbar, or lumbar fractures was correlated with the amount of neural canal impingement (NCI) demonstrated by computerized axial tomography (CT). Average NCI was significantly higher in the 34 patients with neurologic deficits, but the range of NCI was similar to that observed in the 46 patients with no deficits. Burst fractures and fractures in the lumbar spine had the highest average NCI but the lowest percentage of patients with neurologic deficits. The immediate, posttraumatic NS of the 80 patients studied did not directly correlate with the percent of NCI demonstrated on their CT scans.

Adult↗
PubMed1989

Back injuries in college athletes.

Frequency and types of back injuries sustained by intercollegiate athletes were determined by examining medical records of 4,790 athletes that competed in 17 varsity sports over a 10-year period. These athletes sustained 333 back injuries, an injury rate of 7 per 100 participants. Injury rates were significantly higher in football and gymnastics, and 80% of the injuries occurred in practice, 6% in competition, and 14% during preseason conditioning. Muscle strains occurred with much greater frequency than other types of injuries, and acute back injuries were much more prevalent (59%) than overuse injuries (12%) or injuries associated with pre-existing conditions (29%).

Athletic Injuries↗
PubMed1989

Evaluation of patients for high tibial osteotomy.

Fifty-one osteoarthritic knees evaluated by arthroscopic, roentgenographic, and clinical examinations prior to high tibial valgus osteotomy were reevaluated roentgenographically and clinically after a minimum follow-up period of five years (average, 6.2 years; range, 5-8.3 years). The number of good and excellent results decreased over time but was unrelated to the preosteotomy condition of the lateral and patellofemoral compartments as documented by arthroscopy. Knees with 7 degrees to 13 degrees of valgus angulation at the follow-up evaluation had significantly better results than knees with less than 7 degrees of valgus, regardless of the arthroscopic findings. Preosteotomy arthroscopic findings had no predictive value in evaluating patients for this procedure.

Adult↗
PubMed1988

Undetected posttraumatic instability of "stable" thoracolumbar fractures.

A review of 106 consecutive patients who had operative stabilization of thoracolumbar fractures revealed that 16 patients had surgery 4 months to 13 years after injury, for chronic instability. In these 16 patients, there were 8 wedge-compression fractures, 6 flexion-distraction injuries, 1 burst fracture, and 1 fracture-dislocation. All six patients with flexion-distraction injuries and the two patients with either a burst fracture or a fracture-dislocation had good results. Only two of the eight patients with wedge-compression fractures had good results. We concluded from this study that: (a) instability that presents without a progressive spinal deformity may go unrecognized; (b) all types of spine fractures can produce chronic, painful instability; and (c) poor results predominate in wedge-compression fractures operated more than 13 months after injury, regardless of the type of surgical treatment rendered.

Adolescent↗
PubMed1987

Management of non-contiguous vertebral fractures.

Non-contiguous vertebral fractures are not common. In 78 consecutive patients with acute thoracolumbar fractures, we found that 13 patients (16.7%) had non-contiguous spinal injuries. Five patients had a combination of cervical and thoracolumbar injuries and eight had a combination of thoracic and lumbar injuries. Four of the eight patients in the thoracic and lumbar group had posterior surgical stabilisation procedures. Two patients had instrumentation of all injured, non-contiguous vertebrae and healing occurred uneventfully, and two patients had instrumentation of only the major fracture and a progressive deformity occurred at the site of the minor fracture. We concluded that: patients with a spinal fracture should have radiographic evaluation of their entire spine to rule out non-contiguous fractures; if non-contiguous fractures are evident on standard radiographs, all levels of injury should be evaluated with computerised tomography; and all unstable or potentially unstable injuries should be reduced, stabilised, and fused.

Adult↗
PubMed1987

Thoracolumbar fractures in winter sports.

Thoracolumbar fractures occur in 14% of snowmobile injuries, and 5% of Alpine and 8% of freestyle skiing injuries. Proper management of these injuries requires: an awareness that neurologic deficits (specifically genitourinary dysfunction) may be present in spite of a normal neurologic examination; radiographic evaluation that includes computed tomography for the assessment of the middle column of the spine (the key anatomic determinant of spine stability), and standard lateral radiographs of the entire spine to diagnose the 4%-5% of noncontiguous fractures that occur; an understanding of the biomechanical principles of spinal instrumentation; accurate classification of the type of injury (e.g., wedge-compression, flexion-distraction, etc.); and selection of the appropriate instrumentation (bilateral distraction, bilateral compression, or compression combined with distraction) when open reduction and internal fixation are indicated.

Athletic Injuries↗
PubMed1986

Diagnostic dilemmas in foot and ankle injuries.

Differential diagnosis of foot and ankle injuries should include stress fractures of the great toe sesamoids, the shaft of the fifth metatarsal, and the tarsal navicular bone; transchondral talar-dome fractures; fractures of the os trigonum; and dislocating peroneal tendons. Diagnosis of these injuries is challenging because the initial roentgenograms often are normal, and special clinical tests and ancillary studies are required.

Ankle Injuries↗
PubMed1986

Compression-distraction instrumentation of unstable thoracolumbar fractures: anatomic results obtained with each type of injury and method of instrumentation.

The quality of the reductions achieved in a consecutive series of 55 patients with unstable thoracolumbar fractures were correlated with the method of instrumentation, the type and level of injury, the effects of laminectomy and end-plate fractures, and the length of time from injury to surgery. It was found that many of these variables were associated with significant differences (less than 0.05) in the percent correction achieved in anterior compression, angle of deformity, and sagittal plane translation. Specifically: compression combined with distraction produced the best overall anatomic results, but bilateral compression and bilateral distraction were most effective for reducing flexion--distraction and flexion--axial compression (burst) fractures, respectively; two or more level laminectomies adversely affected reductions; end-plate fractures did not; the best reductions were obtained in flexion--distraction injuries; and the poorest reductions occurred in flexion--axial compression injuries, lumbar fractures, and fractures operated on 6 weeks or more after injury.

Adolescent↗