Jonathan L. Schaffer

Does This Patient Have a Torn Meniscus or Ligament of the Knee?: Value of the Physical Examination

ment, using the anterior drawer test, were 3.8 (95% confidence interval [CI], 0.7-22.0) for a positive examination and 0.30 (95% CI, 0.05-1.50) for a negative examination; the Lachman test, 25.0 (95% CI, 2.7-651.0) and 0.1 (95% CI, 0.0-0.4); and the composite assessment, 25.0 (95% CI, 2.1-306.0) and 0.04 (95% CI, 0.01-0.48), respectively. The LRs could not be generated for any specific examination maneuver for a posterior cruciate ligament tear, but the composite assessment had an LR of 21.0 (95% CI, 2.1-205.0) for a positive examination and 0.05 (95% CI, 0.01-0.50) for a negative examination. Determination of meniscal lesions, using McMurray test, had an LR of 1.3 (95% CI, 0.9-1.7) for a positive examination and 0.8 (95% CI, 0.6-1.1) for a negative examination; joint line tenderness, 0.9 (95% CI, 0.8-1.0) and 1.1 (95% CI, 1.0-1.3); and the composite assessment, 2.7 (95% CI, 1.4-5.1) and 0.4 (95% CI, 0.2-0.7), respectively. Conclusion The composite examination for specific meniscal or ligamentous injuries of the knee performed much better than specific maneuvers, suggesting that synthesis of a group of examination maneuvers and historical items may be required for adequate diagnosis.

Is cytoskeletal tension a major determinant of cell deformability in adherent endothelial cells

We tested the hypothesis that mechanical tension in the cytoskeleton (CSK) is a major determinant of cell deformability. To confirm that tension was present in adherent endothelial cells, we either cut or detached them from their basal surface by a microneedle. After cutting or detachment, the cells rapidly retracted. This retraction was prevented, however, if the CSK actin lattice was disrupted by cytochalasin D (Cyto D). These results confirmed that there was preexisting CSK tension in these cells and that the actin lattice was a primary stress-bearing component of the CSK. Second, to determine the extent to which that preexisting CSK tension could alter cell deformability, we developed a stretchable cell culture membrane system to impose a rapid mechanical distension (and presumably a rapid increase in CSK tension) on adherent endothelial cells. Altered cell deformability was quantitated as the shear stiffness measured by magnetic twisting cytometry. When membrane strain increased 2.5 or 5%, the cell stiffness increased 15 and 30%, respectively. Disruption of actin lattice with Cyto D abolished this stretch-induced increase in stiffness, demonstrating that the increased stiffness depended on the integrity of the actin CSK. Permeabilizing the cells with saponin and washing away ATP and Ca2+ did not inhibit the stretch-induced stiffening of the cell. These results suggest that the stretch-induced stiffening was primarily due to the direct mechanical changes in the forces distending the CSK but not to ATP- or Ca(2+)-dependent processes. Taken together, these results suggest preexisting CSK tension is a major determinant of cell deformability in adherent endothelial cells.We tested the hypothesis that mechanical tension in the cytoskeleton (CSK) is a major determinant of cell deformability. To confirm that tension was present in adherent endothelial cells, we either cut or detached them from their basal surface by a microneedle. After cutting or detachment, the cells rapidly retracted. This retraction was prevented, however, if the CSK actin lattice was disrupted by cytochalasin D (Cyto D). These results confirmed that there was preexisting CSK tension in these cells and that the actin lattice was a primary stress-bearing component of the CSK. Second, to determine the extent to which that preexisting CSK tension could alter cell deformability, we developed a stretchable cell culture membrane system to impose a rapid mechanical distension (and presumably a rapid increase in CSK tension) on adherent endothelial cells. Altered cell deformability was quantitated as the shear stiffness measured by magnetic twisting cytometry. When membrane strain increased 2.5 or 5%, the cell stiffness increased 15 and 30%, respectively. Disruption of actin lattice with Cyto D abolished this stretch-induced increase in stiffness, demonstrating that the increased stiffness depended on the integrity of the actin CSK. Permeabilizing the cells with saponin and washing away ATP and Ca2+ did not inhibit the stretch-induced stiffening of the cell. These results suggest that the stretch-induced stiffening was primarily due to the direct mechanical changes in the forces distending the CSK but not to ATP- or Ca2+-dependent processes. Taken together, these results suggest preexisting CSK tension is a major determinant of cell deformability in adherent endothelial cells.

Arthroscopic Microdiscectomy and Selective Fragmentectomy

A prospective outcome study to determine the efficacy and complications associated with posterolateral arthroscopic discectomy was initiated in April 1988. One hundred seventy-five patients with symptoms consistent with a lumbar disc herniation and correlative imaging studies were treated operatively, and 169 were available for followup evaluation. Fifty-nine patients with a central herniation or a nonmigrated sequestered fragment were treated using bilateral biportal posterolateral access, whereas 116 patients with radiographic evidence of a paramedial, foraminal, or extraforaminal herniation were treated using the unilateral uniportal approach. The minimum duration of nonoperative management ranged from 3.5 to 28 months (average, 16 months), and all patients had a minimum of 24 months of postoperative followup. Outcome analysis indicated that 149 procedures were successful, whereas 20 (11.8%) procedures were failures because of persistent radicular symptoms that, in some cases, required open laminotomy. Complications associated with the procedures included one disc space infection, one transient peroneal neuropraxia, and four index extremity skin hypersensitivity. All of these complications resolved without sequelae, and there were no neurovascular complications directly related to the surgical approach.

Development of degenerative spondylosis of the lumbar spine after partial discectomy : comparison of laminotomy, discectomy, and posterolateral discectomy

Study Design The development of degenerative spondylosis after successful operative decompression of the affected nerve root was prospectively evaluated in a comparative case series of 100 patients with a herniated lumbar nucleus pulposus. Objectives The objective of this study was to compare the relative incidence of degenerative spondyloarthrosis after successful posterior laminotomy and discectomy and posterolateral extradural discectomy for decompression of a compromised lumbar nerve root. Summary of Background Data The relationship between the radiographic appearance of degenerative spondylosis and prior operative procedures has been controversial and at times contradictory. The posterior operative approach with a partial discectomy has been associated with a significant incidence of postoperative degenerative spondylosis and intraneural and perineural fibrosis, complications that may be minimized, or perhaps even eliminated, with the posterolateral evacuation of the offending intervertebral disc fragment. Methods Each patient had: 1) not responded favorably to nonoperative treatment, 2) a persistent radiculopathy, 3) correlative imaging studies with no preoperative spondyloarthrosis and 4) minimum 2-year follow-up. Fifty patients were treated by posterior laminotomy and discectomy and fifty were treated by a posterolateral extradural discectomy. Postoperative spondylosis was graded based on the radiographic presence or absence of osteophytes, the intervertebral disc height, the vertebral body alignment and the facet joint changes. Results At an average postoperative follow-up of 65 months, the incidence of a one grade increase in degenerative spondylosis was 80% of the laminotomy and discectomy patients as compared to 39% of the posterolateral discectomy patients. Conclusions The increased incidence of spondyloarthrosis with the posterior approach suggests that minimally invasive posterolateral extradural procedures should be considered for the decompression of a compromised lumbar nerve root.

Outcomes of care and resource utilization among patients with knee or shoulder disorders treated by general internists, rheumatologists, or orthopedic surgeons

PURPOSE Previous studies have suggested that specialists may achieve better clinical outcomes for patients, albeit often at greater cost. We sought to compare outcomes of care and resource utilization among patients with shoulder or knee problems who were treated by general internists, rheumatologists, and orthopedic surgeons. SUBJECTS AND METHODS Outpatients with knee or shoulder complaints who were seen by general internists, rheumatologists, or orthopedic surgeons at an academic medical center were administered questionnaires at enrollment in the study and again 3 months later. The questionnaires included validated measures of satisfaction, functional status, and pain severity, as well as resource utilization. We compared baseline clinical characteristics, satisfaction with care, resource utilization, and changes in function and symptoms during 3 months of follow-up among patients who were cared for by the three different types of providers. RESULTS A total of 534 patients responded to the baseline survey and 436 (82%) to the 3-month follow-up survey. About 60% (n = 323) had knee pain. Orthopedists cared for 40% (n = 211) of the patients, with the remainder treated in approximately equal numbers by general internists or rheumatologists. At baseline, patients of internists had less severe pain (differences of 0.3 to 0.6 points on a 1 to 5 scale, P <0.05) and functional limitations (differences of 0.4 to 0.6 points on a 1 to 5 scale, P <0.0006) than patients of rheumatologists and orthopedic surgeons. Adjusting for baseline differences, there were no significant differences among provider groups in pain relief or functional improvement during follow-up. However, in adjusted analyses, patients with shoulder pain who were cared for by orthopedic surgeons were least satisfied with the office environment [adjusted mean (+/- SD) satisfaction score of 1.6 +/- 0.8 on a 1 to 4 scale for orthopedic surgeons vs 1.3 +/- 0.8 for rheumatologists and 1.4 +/- 0.8 for internists, P = 0.004]. Among patients with knee pain, those treated by rheumatologists and orthopedic surgeons were more satisfied with the doctor-patient interaction (adjusted mean satisfaction scores of 1.1 +/- 0.9 for rheumatologists and 1.2 +/- 0.7 for orthopedic surgeons on a 1 to 4 scale vs 1.4 +/- 0.8 for general internists, P = 0.003). Orthopedic surgeons obtained significantly more radiographs of the knee or shoulder and more magnetic resonance imaging scans of the knee. Rheumatologists performed significantly more aspirations or injection procedures. Among all patients, those treated by rheumatologists were most satisfied with the physician interaction, and those treated by orthopedic surgeons were most satisfied with treatment results. CONCLUSION The relative benefits of specialist compared with generalist care for patients with knee or shoulder pain depend on the importance attached to resource utilization, patient satisfaction, and health outcomes.

Developmental restriction of embryonic calvarial cell populations as characterized by their in vitro potential for chondrogenic differentiation

The mechanism(s) by which the cells within the calvaria tissue are restricted into the osteogenic versus the chondrogenic lineage during intramembranous bone formation were examined. Cells were obtained from 12‐day chicken embryo calvariae after tissue condensation, but before extensive osteogenic differentiation, and from 17‐day embryo calvariae when osteogenesis is well progressed. Only cell populations from the younger embryos showed chondrogenic differentiation as characterized by the expression of collagen type II. The chondrocytes underwent a temporal progression of maturation and endochondral development, demonstrated by the expression of collagen type II B transcript and expression of collagen type X mRNA. Cell populations from both ages of embryos showed progressive osteogenic differentiation, based on the expression of osteopontin, bone sialoprotein, and osteocalcin mRNAs. Analysis using lineage markers for either chondrocytes or osteoblasts demonstrated that when the younger embryonic cultures were grown in conditions that were permissive for chondrogenesis, the number of chondrogenic cells increased from ∼15 to ∼50% of the population, while the number of osteogenic cells remained almost constant at ∼35–40%. Pulse labeling of the cultures with BrdU showed selective labeling of the chondrogenic cells in comparison with the osteogenic cells. These data indicate that the developmental restriction of skeletal cells of the calvaria is not a result of positive selection for osteogenic differentiation but a negative selection against the progressive growth of chondrogenic cells in the absence of a permissive or inductive environment. These results further demonstrate that while extrinsic environmental factors can modulate the lineage progression of skeletal cells within the calvariae, there is a progressive restriction during embryogenesis in the number of cells within the calvaria with a chondrogenic potential. Finally, these data suggest that the loss of cells with chondrogenic potential from the calvaria may be related to the progressive limitation of the reparative capacity of the cranial bones.

Development and validation of a patient satisfaction scale for musculoskeletal care

OBJECTIVE To test the hypothesis that 3 distinct domains of patient satisfaction with musculoskeletal care--satisfaction with the office environment, provider-patient interaction, and treatment outcomes--can be measured reliably and, when considered separately, are more valid indicators of satisfaction than global measures. METHODS Three hundred ninety-nine outpatients who presented with knee or shoulder pain were enrolled in a prospective cohort study. We measured patient satisfaction with musculoskeletal care by adapting a widely used generic satisfaction survey. RESULTS Each domain of the scale was internally consistent, with Cronbachs alphas for satisfaction with the office environment, provider-patient interaction, and treatment outcome subscales of 0.68, 0.95, and 0.93, respectively. Validity correlations demonstrated the greater specificity of the subscales than global measures for particular aspects of musculoskeletal care. CONCLUSIONS The musculoskeletal-specific satisfaction scale has excellent reliability and good discriminant validity. From a policy perspective, the distinct subscale structure is critical because problems within each domain may have different remedies.

Trends in knee magnetic resonance imaging.

Objective. To assess trends in knee magnetic resonance imaging (MRI) use and accompanying management changes to determine whether indications for this test have changed over time. Data Sources. Large administrative database containing health care information for 587,010 people living in 1 state who were enrolled in the Medicare or Medicaid programs. They all had used health services during 3 consecutive years between 1991 to 1995. Methods. We performed a retrospective cohort study examining the rates of lower extremity MRI in successive years and calculated the proportion of patients who were seen by a knee specialist or underwent knee surgery subsequent to the MRI. Results. The annual rate of knee MRI was 1.4 per 1000 person-years in 1991 and increased by 140% to 3.4 per 1000 person-years by 1995 (P = 0.001). Approximately half of patients who underwent a knee MRI in 1991 had a diagnosis of internal derangement of the knee in the prior year; this figure dropped to 35% in 1995 (P < 0.001). The percentage of patients undergoing a knee MRI who had no record of any knee diagnosis in the prior year grew from 13% in 1991 to 33% in 1995 (P < 0.001). Over the 5 years of the study, the percentage of patients whose knee MRI was followed by specialist care or knee surgery decreased from 68% to 58%, a relative change of 15% (P < 0.005). Conclusion. Knee MRI use increased sharply during the study period, but the proportion of such patients who had a prior diagnosis of internal derangement or subsequently saw a knee specialist or underwent knee surgery decreased. This finding indicates that the criteria for knee MRI appear to have broadened substantially during this period.

Physical properties of hydrated tissue determined by surface interferometry of laser-induced thermoelastic deformation

Knee meniscus is a hydrated tissue; it is a fibrocartilage of the knee joint composed primarily of water. We present results of interferometric surface monitoring by which we measure physical properties of human knee meniscal cartilage. The physical response of biological tissue to a short laser pulse is primarily thermomechanical. When the pulse is shorter than characteristic times (thermal diffusion time and acoustic relaxation time) stresses build and propagate as acoustic waves in the tissue. The tissue responds to the laser-induced stress by thermoelastic expansion. Solving the thermoelastic wave equation numerically predicts the correct laser-induced expansion. By comparing theory with experimental data, we can obtain the longitudinal speed of sound, the effective optical penetration depth and the Grüneisen coefficient. This study yields information about the laser tissue interaction and determines properties of the meniscus samples that could be used as diagnostic parameters.

Arthroscopic microdiscectomy: Comparison of preoperative and postoperative imaging studies

Forty-three patients with symptomatic lumbar disc herniations underwent paralumbar arthroscopic disc extraction by a uniportal or biportal approach and postoperative imaging studies. Thirty-one patients were subjected to immediate postoperative computed tomography (CT) at the operative site. The other 12 underwent magnetic resonance imaging (MRI at varying times postoperatively. Images obtained before and after surgery were magnified; the herniation area (H) and the spinal canal area (C) were measured by computerized digitization. The H/C ratio was calculated, and the percentage of canal clearance was obtained in each case. Immediate postoperative CT imaging in 16 of 18 patients with subligamentous and extraligamentous nonmigrated herniation showed a significant change in the external geometry of the annulus and canal clearance (75% to 100% canal clearance). Less compelling change in the postoperative CT images was unexpectedly seen with extraforaminal and foraminal herniations. This result may be attributable to limitations in our study methodology and not to inadequate decompression. Follow-up MRI on these patients within 8 weeks postoperatively did eventually show significant change in two cases that were initially not significant. This study confirms that the arthroscopic microdiscectomy technique effectively extracts herniated disc fragments and alters posterior annular contour, including removal of sequestered pieces.