Biomedical subjects

J S Keene

Publications and source records attributed to J S Keene.

At least 19 recordsLinked to original sources

PubMed2007

Classification and localization of acetabular labral tears.

OBJECTIVE: The purpose of this study was to compare the findings on hip MR arthrography (MRA) with the published MRA and arthroscopic classifications of hip labral tears and to evaluate a clock-face method for localizing hip labral tears. DESIGN/PATIENTS: We retrospectively reviewed 65 hip MRA studies with correlative hip arthroscopies. Each labrum was evaluated on MRA using the classification system of Czerny and an MRA modification of the Lage arthroscopic classification. In addition, each tear was localized on MRA by using a clock-face description where 6 o'clock was the transverse ligament and 3 o'clock was anterior. These MRA findings were then correlated with the arthroscopic findings using the clock-face method of localization and the Lage arthroscopic classification of labral tears. RESULTS: At MRA, there were 42 Czerny grade 2 and 23 grade 3 labral tears and 22 MRA Lage type 1, 11 type 2, 22 type 3 and 10 type 4 tears. At arthroscopy, there were 10 Lage type 1 flap tears, 20 Lage type 2 fibrillated tears, 18 Lage type 3 longitudinal peripheral tears and 17 Lage type 4 unstable tears. The Czerny MRA classification and the modified MRA Lage classification had borderline correlation with the arthroscopic Lage classification. Localization of the tears using a clock-face description was within 1 o'clock of the arthroscopic localization of the tears in 85% of the patients. CONCLUSIONS: The Lage classification, which is the only published arthroscopic classification system for hip labral tears, does not correlate well with the Czerny MRA or an MRA modification of the Lage classification. Using a clock-face description to localize tears provides a way to accurately localize a labral tear and define its extent.

Acetabulum↗

PubMed1995

MR imaging of a meniscal ossicle.

We report the MR appearance of a meniscal ossicle, which is an unusual etiology for knee pain. The role of MR in differentiating a meniscal ossicle from a loose body is presented. The MR images also demonstrated associated tibial cartilage thinning and a possible meniscal tear. These MR findings led to arthroscopic treatment rather than conservative management. A review of the literature on meniscal ossicles is also presented.

Adult↗

PubMed1994

Risk factors for restricted motion after anterior cruciate reconstruction.

A retrospective review of 373 patients who had undergone anterior cruciate ligament (ACL) reconstruction utilizing the central third of the patellar tendon was undertaken to identify those factors that placed a patient at risk for restricted postoperative motion (flexion < or = 125 degrees or flexion contracture > or = 10 degrees). Stepwise logistic regression analysis determined that the variables most strongly correlated with restricted final range of motion (ROM) were open surgery (P = .0008) and reconstruction performed < or = 7 days after the initial injury (P = .004). Age, associated meniscal repair, or associated collateral ligament injuries did not significantly affect the ROM. A subgroup of 204 patients arthroscopically reconstructed more than 7 days post-injury were significantly less likely to have limited motion when ROM exercises were begun within 2 days of surgery (P = .008). These data support delayed, arthroscopic ACL reconstruction followed by early ROM exercises as useful techniques for avoiding postoperative motion problems.

Adolescent↗

PubMed1993

Diagnosis of meniscal tears of the knee with MR imaging: effect of observer variation and sample size on sensitivity and specificity.

OBJECTIVE: A wide range in the efficacy of MR imaging for the diagnosis of meniscal tears of the knee has been reported. To evaluate two possible causes for this variation, we studied how sensitivity and specificity are affected when different observers and sample sizes are used. MATERIALS AND METHODS: Two hundred MR examinations of the knee in patients for whom the results of arthroscopy were available were used for the study. One hundred eight medial meniscal tears and 58 lateral meniscal tears were found at arthroscopy. The sensitivity and specificity for detection of meniscal tears were determined for the original interpretations and retrospective evaluations by three observers. Comparisons were also made between sample sizes of 25 and 100. chi 2 analysis was used for unmatched data sets and McNemar's statistic was used for matched sets. RESULTS: For the 200 examinations, the sensitivity was 0.89-0.93 for medial meniscal tears and 0.79-0.83 for lateral meniscal tears. The specificity was 0.86 for medial meniscal tears and 0.90-0.92 for lateral meniscal tears. Sensitivity and specificity varied widely among different observers and different sample sizes. However, we found no significant difference between any of the comparisons at the p < .05 level. The largest interobserver variation occurred in the detection of lateral meniscal tears, with a sensitivity of 0.71 for one observer and 0.88 for another observer (p = .16). The largest variation between sets of 100 examinations was a change in sensitivity for detection of lateral meniscal tears from 0.74 to 0.88 for the original interpretations (p = .10). For the sample sets of 25 cases, the variation was even larger, with the sensitivity for detection of lateral meniscal tears varying from 0.5 for one set to 1.0 for another. CONCLUSION: We conclude that chance variation related to sample size can cause large but not statistically significant variations in sensitivity and specificity in this setting. These variations are of sufficient magnitude to explain many of the differences in reported sensitivity and specificity for MR imaging in the diagnosis of meniscal tears. We found no significant difference in observer performance.

Adolescent↗

PubMed1993

MR diagnosis of meniscal tears of the knee: importance of high signal in the meniscus that extends to the surface.

OBJECTIVE: The presence of intrameniscal signal in contact with the surface is a commonly used criterion for the diagnosis of meniscal tear. This signal presumably represents the actual tear in the meniscus. However, some menisci with signal that contacts the surface are noted to be intact at arthroscopy whereas other menisci that have no signal in contact with the surface are found to be torn. We investigated the relationship between the presence of a meniscal tear at arthroscopy and the location within the menisci of signal that contacted the surface. We hypothesized that patterns were present that would improve the accuracy of MR diagnosis of a meniscal tear. MATERIALS AND METHODS: We reviewed the MR and arthroscopic findings from 200 consecutive patients who had both knee MR examinations and knee arthroscopy. There were 108 medial and 58 lateral meniscal tears on arthroscopy. Each MR examination was reviewed for three aspects of intrameniscal signal: the number of images showing signal possibly or definitely contacting the surface, the specific surfaces involved, and the signal location. The coronal and sagittal images were evaluated separately. We correlated each of these features with the presence of a meniscal tear at arthroscopy. RESULTS: Menisci with signal possibly contacting the surface had the same frequency of tears (three tears in 33 menisci) as menisci without signal contacting the surface (15 tears in 194 menisci). More than 90% of menisci with signal contacting the surface on more than one image were torn, but only 55% of medial and 30% of lateral menisci with such signal on only one image were torn. In the torn menisci with signal contacting the surface, such signal was seen only on sagittal MR images in 31% of the medial menisci and 45% of the lateral menisci. Sixteen percent of the torn lateral menisci had signal contacting the meniscal surface in only the anterior two thirds of the meniscus, whereas this was true in only 2% of the torn medial menisci. Distinct patterns were not seen in the association between tears and signal contacting either the superior or the inferior surface. CONCLUSION: We found definite patterns in the location of intrameniscal signal that comes in contact with the meniscal surface. These patterns vary in the frequency of associated meniscal tears. Although menisci with internal signal in contact with the surface are usually torn, a tear is less likely if such signal is present on only one image. Tears may be identifiable on only one image plane. Tears in the anterior horn of the lateral meniscus are not uncommon. Knowledge of these patterns should help in the MR diagnosis of meniscal tears.

Adolescent↗

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↗