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Biomedical subjects

D R Anderson

Publications and source records attributed to D R Anderson.

At least 127 records · Page 7Linked to original sources
PubMed1994

Efficacy of injectable anticholinergic drugs against soman-induced convulsive/subconvulsive activity.

Six FDA approved, injectable compounds [benztropine (BZT); biperiden (BIP); dicyclomine (DCL); l-hyoscyamine (HYO); orphenadrine (ORP); scopolamine (SCP)] were each compared to diazepam (DZ, the standard) in male guinea pigs against ongoing soman-induced convulsive or sub-CV (CV/sub-CV) activity. Three trained graders concurrently assigned CV/sub-CV scores to each animal based on signs of intoxication at various times post-soman. Animals received (im) pyridostigmine (26 micrograms/kg) 30 min before soman (56 micrograms/kg; 2 x LD50), atropine (2 mg/kg) admixed with 2-PAM (25 mg/kg) at one min after soman, and the candidate drug preparation at 5.67 min post soman, a time when CV activity was assured. BIP and SCP were effective over dosage ranges between 10 and 0.3, and 1.0 and 0.13 mg/kg, respectively, while the other preparations were less effective at their respective maximum dosages. At the most effective dosages of SCP (1.0 mg/kg) and BIP (10 mg/kg), the CV/sub-CV scores were significantly lower (p < 0.05) than those of DZ. Only 33% survival was observed at each of two doses of ORP and one dose of HYO; therefore, no further testing was done with these compounds. Using freshly prepared solutions, DCL (up to 40 mg/kg) and BZT (up to 96 mg/kg) were tested with mixed results; DCL lowered lethality while BZT increased lethality. CV/sub-CV scores for the most effective dose of DCL and BZT were, however, lower than those of DZ. SCP is an antimuscarinic drug devoid of antinicotinic activity, while BIP possesses antimuscarinic, antinicotinic, antispasmodic and anti-N-methyl-D-aspartate activity. Recent evidence suggests that, in late stages of intoxication by nerve agents, noncholinergic, excitatory amino acid receptors may become involved and necessitate the use of a multi-action drug like BIP. The findings herein suggest that SCP and BIP are superior to DZ, but further studies are needed to determine which drug or drug class should be pursued in more advanced testing.

Animals↗
PubMed1994

Efficacy comparison of scopolamine (SCP) and diazepam (DZ) against soman-induced lethality in guinea pigs.

Diazepam (DZ) and scopolamine (SCP) are known to be beneficial when each is used in combination with atropine (AT) + oxime therapy against intoxication by soman, but the efficacy of each might be expected to vary with the dosage of AT. Thus the therapeutic efficacy of SCP (5 doses; 0-0.86 mg/kg) versus DZ (5 doses; 0-5 mg/kg), when used in conjunction with AT (3 doses; 0.5-8 mg/kg) + 2-PAM (25 mg/kg) therapy, was tested in groups of pyridostigmine pretreated guinea pigs exposed to 1.6, 2.0, 2.5 or 3.2 LD50s of soman. Response surface methodology was employed to describe the relationship between lethality and the AT/DZ or AT/SCP dosages. Results show that within the indicated dose ranges used, the efficacy of SCP is not dependent on the presence of AT, whereas AT is needed for DZ to maintain the lowest probability of death. These findings suggest that in guinea pigs SCP could supplement AT or replace DZ as therapy against nerve agent intoxication.

Animals↗
PubMed1994

Relaxation of retinal pericyte contractile tone through the nitric oxide-cyclic guanosine monophosphate pathway.

PURPOSE: Pericytes are contractile cells outside the endothelial lining of capillaries. The study investigated whether nitric oxide, known to cause relaxation of vascular smooth muscle cells, also relaxes pericytes. METHODS: Cultured bovine pericytes were exposed to a nitric oxide donor, sodium nitroprusside, and to 8-bromoguanosine 3':5'-cyclic monophosphate (8-bromo cGMP) in the presence and in the absence of methylene blue, an inhibitor of guanylate cyclase. Relaxation was assessed by counting the loss of wrinkles induced by pericytes when they are cultured on thin sheets of silicone. Intracellular cyclic guanosine monophosphate (cGMP) was measured by radioimmunoassay. RESULTS: Pericytes relaxed to sodium nitroprusside (3 x 10(-8) to 10(-4) M) in a concentration-dependent manner (ED50: 10(-6) M). The maximal response was characterized by the loss of almost all the wrinkles. The half-maximal relaxation was strongly inhibited by methylene blue (3 x 10(-7) M). Sodium nitroprusside (3 x 10(-6) M) caused a 14-fold increase in the intracellular concentration of cGMP, an effect inhibited by methylene blue (3 x 10(-7) M). The cGMP analogue, 8-bromo-cGMP (10(-5) and 3 x 10(-5) M) strongly relaxed the cells in a concentration-dependent manner, but the relaxation was not reduced by methylene blue (3 x 10(-7) M). CONCLUSIONS: Sodium nitroprusside, which releases nitric oxide, strongly relaxes pericytes through an increase of cGMP. Therefore, the presence of the endothelium-derived relaxing factor nitric oxide in the microcirculation can modulate the tone of pericytes, and it thus has the potential to influence blood flow in capillaries.

Animals↗
PubMed1993

Efficacy and cost of low-molecular-weight heparin compared with standard heparin for the prevention of deep vein thrombosis after total hip arthroplasty.

PURPOSE: To compare the efficacy, safety, and cost-effectiveness of low-molecular-weight heparin with standard heparin for the prevention of deep vein thrombosis after total hip arthroplasty. DATA IDENTIFICATION: Studies were identified by MEDLINE search and review of bibliographies of retrieved articles. Hospital resources used in treating deep vein thrombosis and bleeding complications after total hip arthroplasty were estimated using retrospectively collected data from 447 patients who participated in a recently completed randomized controlled deep vein thrombosis prophylaxis trial at our center. STUDY SELECTION: Randomized controlled trials directly comparing a low-molecular-weight heparin preparation with standard heparin for the prevention of deep vein thrombosis after total hip arthroplasty were potentially eligible for the meta-analysis. DATA EXTRACTION: Data from eligible studies were extracted independently by two of the authors. Multiple regression analysis of data from the patient cohort was used to estimate the effect of deep vein thrombosis and bleeding on length of hospital stay. A hypothetical North American price for low-molecular-weight heparin was determined based on the ratio between low-molecular-weight heparin and standard heparin in France. Costs were based on weighted per-diem hospital expenditures and physician fees for procedures and reported in 1992 U.S. dollars. RESULTS OF DATA SYNTHESIS: Meta-analysis of six eligible trials determined that low-molecular-weight heparin was significantly more effective than standard heparin at preventing deep vein thrombosis after total hip arthroplasty (common odds ratio, 0.72; 95% CI, 0.53 to 0.95). However, this benefit was restricted to the prevention of proximal deep vein thrombosis (common odds ratio, 0.40; CI, 0.28 to 0.59). No significant differences were found in the rates of distal deep vein thrombosis or total, major, or minor bleeding between the two groups. Based on a 2.6 to 1 price ratio between low-molecular-weight heparin and standard heparin, use of low-molecular-weight heparin would save the health care system about $50,000 per 1000 patients treated. Sensitivity analysis shows that if the low-molecular-weight heparin/standard heparin price ratio exceeds 3.7 (the threshold value lies between 0.8 and 5.5 based on the extremes of the 95% CI of the common odds ratios for deep vein thrombosis and bleeding complications), use of low-molecular-weight heparin is more expensive. At a price ratio of 10, it would cost more than $250,000 to treat 1000 patients with low-molecular-weight heparin compared with standard heparin or about $5000 for each additional deep vein thrombosis prevented with low-molecular-weight heparin. CONCLUSIONS: Low-molecular-weight heparin is more effective and is at least as safe as standard heparin for the prevention of deep vein thrombosis after total hip arthroplasty. Based on the current French price ratio of low-molecular-weight heparin to standard heparin, the use of low-molecular-weight heparin in North America would result in overall savings in cost; however, the relative cost-effectiveness is critically dependent on the price ratio between the two drugs. Further research is needed to compare the cost-effectiveness of low-molecular-weight heparin with other prophylactic regimens and postoperative deep vein thrombosis management strategies.

Cost-Benefit Analysis↗
PubMed1993

Evaluation of a portable prothrombin time monitor for home use by patients who require long-term oral anticoagulant therapy.

BACKGROUND: The anticoagulant activity of warfarin sodium is monitored by the prothrombin time (PT). The introduction of a portable PT monitor has raised the possibility that patients could reduce the inconvenience of anticoagulant therapy by measuring their PT at home. We performed this study to determine the feasibility and accuracy of home use of the portable PT monitor. METHODS: A prospective cohort study was performed in consecutive eligible patients who required long-term anticoagulant therapy. Patients performed multiple measurements of their PT at home by means of the portable monitor and at their usual laboratory within a 4-hour interval. The accuracy of the portable monitor was evaluated by two criteria for agreement. Standard agreement was achieved if the portable monitor and laboratory results were both either within or outside the patient's targeted therapeutic range or if the two results were within 0.4 international normalized ratio units of each other. Expanded agreement was achieved if both the portable monitor and laboratory results were within +/- 0.4 international normalized ratio units of the targeted therapeutic range. RESULTS: Forty patients (19 men and 21 women, aged 25 to 74 years) were followed up for 6 to 24 months by means of the portable PT monitor. The mean level of agreement achieved per patient was 83% (95% confidence interval, 79% to 87%) by the standard criteria and 96% (95% confidence interval, 94% to 98%) by the expanded criteria. Twenty-seven patients (68%) and 39 patients (98%) achieved more than 80% agreement by the standard and the expanded criteria, respectively. Questionnaire results revealed that 97% of the patients preferred using the portable monitor to measure their PT. CONCLUSIONS: Patients receiving long-term anticoagulant therapy achieved a high rate of clinically important agreement between self-measurements of the PT with the use of a portable monitor and laboratory PT results. Patients strongly preferred using the portable monitor to measure their PT levels. The use of the portable monitor as the primary method for measuring the PT can be recommended in selected patients receiving long-term anticoagulant treatment.

Administration, Oral↗
PubMed1993

The effects of depth of penetration, screw orientation, and bone density on sacral screw fixation.

Obtaining adequate sacral fixation is an important and challenging clinical problem. Bicortical screw fixation has been used to provide improved mechanical strength. The goal of this study was to evaluate the effects of depth of penetration (unicortical versus bicortical), orientation (medial versus lateral), and bone density on the strength of the bone-screw interface. Seven-millimeter Steffee screws (Acromed, Cleveland, Ohio) were placed in human cadaveric sacra. The screws were placed either medially into the centrum of the S1 body or laterally into the sacral ala. The fixation systems used, either bicortical or unicortical, were tested on a Universal testing machine. The specimens were loaded to failure and biomechanical parameters were measured. Medially oriented screws sustained the highest load to failure. In an older population, unicortical fixation sustained load to failure and initial compliance findings were similar to those for bicortical fixation. The regional bone density in the centrum of the first sacral body was denser than that in the lateral alar region, and also provided more rigid bone screw fixation.

Aged↗
PubMed1993

The use of an indwelling Teflon catheter for subcutaneous heparin administration during pregnancy. A randomized crossover study.

BACKGROUND: The use of subcutaneous heparin, the therapy of choice for women requiring anticoagulant prophylaxis during pregnancy, is problematic because of the discomfort produced by repeated injections. An indwelling subcutaneous Teflon catheter that can be left in place for 1 week recently became available for use as an entry port for parenteral therapy. Since the use of this catheter has the potential to overcome some of the problems of long-term heparin therapy, we decided to compare this Teflon catheter with twice-daily subcutaneous injections in women requiring heparin during pregnancy. METHODS: In a randomized, multiple-crossover study, patients alternated every 2 weeks between having heparin administered through the indwelling Teflon catheter and receiving heparin via subcutaneous injections. After each 4-week cycle, patients completed a questionnaire designed to determine their preferred method of heparin administration. The side effects, doses, and anticoagulant activity of heparin with the two delivery systems were also compared. RESULTS: Twelve patients completed one to five 4-week cycles of heparin therapy. Ten of the patients selected the Teflon catheter as the preferred route of heparin administration (P = .04) and 11 patients reported that the catheter caused less pain and bruising than twice-daily subcutaneous injections (P < .01). Five patients developed urticarial reactions at the sites of heparin injections. These reactions tended to be more severe when the Teflon catheter was used, and two women discontinued using the catheter after the first cycle because of this complication. There were no differences in heparin dose requirements or achieved activated partial thromboplastin times between the two routes of heparin administration. CONCLUSIONS: Most pregnant women in our study preferred to have subcutaneous heparin administered through an indwelling Teflon catheter rather than by twice-daily injections. Heparin given through the Teflon catheter was bioavailable and caused less local bruising than twice-daily injections. Urticarial reactions to heparin tended to be more severe with the use of the Teflon catheter and resulted in the discontinuation of the device's use in two of 12 patients.

Adult↗
PubMed1993

Limitations of impedance plethysmography in the diagnosis of clinically suspected deep-vein thrombosis.

OBJECTIVE: To re-evaluate the accuracy of impedance plethysmography (IPG) for the detection of proximal deep-vein thrombosis (DVT). PATIENTS: A total of 384 of 390 consecutive outpatients referred with their first episode of clinically suspected deep-vein thrombosis. SETTING: University-based tertiary care medical center associated with a cancer clinic. DESIGN: A retrospective analysis of a cohort of patients whose data were recorded and stored prospectively on a computerized data base over a 22-month period. MEASUREMENTS: Patients were evaluated by a physician and underwent IPG testing. Patients with abnormal IPG tests and those with normal IPG results in whom there was a high clinical suspicion of DVT or in whom follow-up IPG testing was not feasible were referred for venography. Venography and IPG results were interpreted by a panel of independent observers. Two models of the IPG instrument were used (Codman 200 and Electrodiagnostic Instruments 800). RESULTS: Venography (or compression ultrasound) was done in 57 patients with an abnormal IPG test and in 85 patients with normal IPG results. Impedance plethysmography was abnormal in only 37 of 56 patients with confirmed proximal-vein thrombosis (sensitivity, 66%; 95% Cl, 52% to 78%). Of the 57 patients with an abnormal IPG result, 37 had DVT (positive predictive value, 65%). The sensitivity for the detection of proximal DVT did not differ between the IPG 200 and 800 instruments (sensitivity, 63% and 71%, respectively; P > 0.2). Of the 19 proximal-vein thrombi not detected by IPG, 12 (63%) were occlusive and 11 (58%) involved at least the popliteal and superficial femoral veins. CONCLUSIONS: At our center, IPG has a far lower sensitivity for proximal-vein thrombosis than has been previously reported for symptomatic outpatients. The reason for this low sensitivity is unclear. Our findings indicate that centers using IPG as the initial diagnostic test for suspected DVT should be aware of this potential problem and should consider re-evaluating the sensitivity of their IPG machines by performing venography in a cohort of their patients with normal test results.

Female↗
PubMed1993

Evaluation of baseline-related suprathreshold testing for quick determination of visual field nonprogression.

OBJECTIVE: To evaluate a commercially available means of baseline-related suprathreshold examination designed to detect visual field worsening. DESIGN: Patients for whom results of a baseline series of static-threshold visual field examinations were available underwent both a second static-threshold examination (full-threshold strategy; average time, 15 minutes) and a baseline-related suprathreshold examination ("fast-threshold" strategy; average time, 5 minutes). RESULTS: Most of the 1702 points examined were apparently unchanged from baseline, showing with either method only the degree of variation expected from the measurement inconsistency (short-term fluctuation). For points that did show a change, the changes shown by the two methods were correlated. Change in the field as a whole, represented by a cluster of locations showing deterioration, was evident more frequently with the standard testing strategy: 11 of 37 field examinations showed deterioration by both methods and an additional 11 examinations showed deterioration by the full-threshold method only. CONCLUSIONS: Each examination method identified pointwise changes not detected by the other, the combined effect of false-positive errors (imperfect specificity) and false-negative errors (imperfect sensitivity) with each of the two methods. The findings relating to clusters could represent a better sensitivity of the full-threshold method in detecting visual field deterioration, a better specificity of the suprathreshold method, or both.

Evaluation Studies as Topic↗
PubMed1993

In vitro load transmission in the canine knee: the effect of medial meniscectomy and varus rotation.

The purpose of this study was to determine the in vitro load-transmission characteristics of the canine knee, paying particular attention to the positioning effect of the meniscus in the coronal plane. The intact joint was first loaded and then tested under two different loading conditions after a complete medial meniscectomy. The first set of test conditions attempted to simulate those used by previous investigators, by ignoring the spacer effect of the meniscus. The second set of tests were carried out following varus rotation of the joint (to account for the loss of the meniscal spacer) to assure initial contact in both tibiofemoral compartments at the start of test cycle. It is presumed that this varus realignment occurs during weight bearing following meniscectomy in vivo. As in previous studies, the joints experienced slightly larger displacements (although not statistically significant) and had lower stiffness values following medial meniscectomy than when intact. However, following varus realignment of the joint after meniscectomy, the displacement was markedly smaller (-35% to -49%; P < 0.01) and the structural stiffness was much greater (47-123%; P < 0.05) over the range of forces analyzed, compared with the intact joint. The ratio of dissipated to input energy was 42% for the intact joint, and increased following meniscectomy to 54% (P < 0.05) with realignment and 55% (P < 0.05) without realignment. Measured contact area decreased by 17% (P < 0.05) following meniscectomy alone, and by 12% (P < 0.05) following meniscectomy with realignment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The effect of simulated cataract on the glaucomatous visual field.

PURPOSE: The current study is designed to determine the effect of light scattering (simulated cataract) on glaucomatous visual fields. METHODS: Twelve patients with relative scotomas caused by glaucoma underwent the 30-2 threshold test with the Humphrey Visual Field Analyzer twice: once with and once without having a light-diffusing piece of ground glass in front of the eye, which, in previous experiments, has been shown to decrease perimetric threshold by 4.4 decibels (dB) in normal eyes. As controls, 12 patients underwent the same examination with and without a piece of clear glass in front of the eye. In each pair of fields, five points were analyzed within the relative scotoma and compared with five points in a normal area of the opposite hemifield. RESULTS: The diffusing ground glass produced a mean decrease of perimetric threshold of 5.7 dB (standard deviation [SD] = 3.3 dB) within the area of relative scotoma compared with 6.1 dB (SD = 2.4 dB) within the normal area and 4.4 dB (SD = 2.25 dB) at the fovea. The differences between means were not statistically significant. In addition, the diffusing glass did not affect the corrected pattern SD (CPSD) index (6.5 dB with the diffuser and 6.5 dB without). CONCLUSION: Light scattering depresses the glaucomatous visual field diffusely. Relative glaucomatous scotomas and normal areas are depressed equally, expressed as change in decibel of sensitivity. Therefore, in following patients with cataracts and glaucoma, depression of threshold sensitivity in glaucomatous areas out of proportion to normal areas should not be attributed to the light-scattering effect of the cataract, but rather to possible worsening of glaucomatous damage.

Aged↗
PubMed1993

The effects of non-weight-bearing and limited motion on the tensile properties of the meniscus.

Recent clinical studies have suggested that many of the complications of prolonged immobilization after knee surgery can be prevented by permitting early motion while minimizing loading of healing tissues. The purpose of this study was to determine the effects of such a regimen on the tensile properties of the meniscus. The right knee of 10 skeletally mature sheep received a sham operation after which the hindlimb was placed in a harness that prevented weight bearing while permitting limited knee motion. The left knee served as the nonoperated control. Twelve weeks after surgery, paired specimens from the medial meniscus of each limb were tested in tension with the load parallel to the circumferentially oriented collagen fibers. No significant differences in the modulus, tensile strength, and ultimate strain between treated and control medial menisci were identified. Our data thus suggest that preventing weight bearing while permitting even limited motion of the knee will prevent any detrimental effect on the tensile properties of the meniscus in the circumferential direction.

Animals↗
PubMed1993

Control of anticoagulant and antiplatelet therapy. Managing patients with acute thrombotic disorders.

Indications for using standard anticoagulants, heparin and warfarin; the dosage and route of administration; the importance of monitoring therapy with reliable laboratory indices; and complications of therapy are discussed. Acetylsalicylic acid and ticlopidine can be used as antiplatelet agents. Because their effect on platelet function is not monitored clinically, their clinical indications are emphasized.

Administration, Oral↗
PubMed1992

Thrombolytic therapy for the treatment of acute pulmonary embolism.

OBJECTIVES: To determine whether thrombolytic therapy reduces the rate of death or complications in patients with acute pulmonary embolism and whether a particular thrombolytic regimen is more effective than others. DATA SOURCES: The key words "fibrinolytic agents," "plasminogen activators," "streptokinase," "urokinase" and "pulmonary embolism" were used to search MEDLINE for relevant articles in English; the bibliographies of these articles were reviewed for additional publications. STUDY SELECTION: Articles were included if they were of a randomized controlled design; 10 such articles were found. DATA EXTRACTION: Ten trials were appraised with the use of the following methodologic criteria: a clear description of the study population; use of objective criteria to diagnose pulmonary embolism and to assess outcomes; use of clinically relevant outcomes; and blinded outcome assessments. RESULTS: In the nine trials that met the methodologic criteria thrombolytic therapy led to a more rapid resolution of the radiographic and hemodynamic abnormalities associated with acute pulmonary embolism than did anticoagulant therapy alone, although these benefits were short-lived. No difference was detected in the death rate or the resolution of symptoms between patients receiving thrombolytic therapy and those receiving anticoagulant therapy alone. In addition, bleeding complications were more frequent and serious in patients who received lytic therapy, although these events were related to the use of invasive procedures. CONCLUSION: There is a lack of evidence that thrombolytic therapy improves clinically relevant outcomes of patients with acute pulmonary embolism. This may be a reflection of the small sample size of the clinical trials. Further research is required to define the role of thrombolytic therapy in the management of patients with acute pulmonary embolism.

Evaluation Studies as Topic↗
PubMed1992

Immune-related disease and normal-tension glaucoma. A case-control study.

We reviewed the charts of 67 patients with the diagnosis of normal-tension glaucoma listed in the Bascom Palmer Eye Institute computer database. These patients were matched with respect to age, race, and sex with an equal number of patients having ocular hypertension. All medical diagnoses in the charts for both groups were tabulated and classified as either immune-related or non-immune-related. Twenty (30%) patients with normal-tension glaucoma had one or more immune-related disease(s) compared with five (8%) patients in the comparison group (P = .00134, McNemar statistic with continuity correction).

Aged↗
PubMed1992

Bilateral striopallidodentate calcinosis: cerebrospinal fluid, imaging, and electrophysiological studies.

We report the genetic, clinical, electrophysiological, and imaging studies in a family with bilateral striopallidodentate calcinosis (Fahr's disease). The intracerebral calcium deposits occurred before onset of the symptoms in the third decade of life. Progressive neurological deterioration occurred in the fifth decade of life in the proband. Cerebrospinal fluid homocarnosine, a central nervous system-specific peptide, was increased twofold in patients with autosomal dominant bilateral stripallidodentate calcinosis; in sporadic cases, there was no detectable homocarnosine and a decreased level of histidine. With advancing age, the amount of calcification increases, but it has not been determined if a critical amount must be reached before symptoms occur. Computerized tomography is superior to magnetic resonance imaging for radiological diagnosis. Despite diffuse striatal calcification, striatal 6-[18F]fluoro-L-dopa uptake did not reveal any difference between patients and control subjects, from which we infer persisting integrity of the nigrostriatal dopaminergic pathway.

Adult↗
PubMed1992

Healing of the medial collateral ligament following a triad injury: a biomechanical and histological study of the knee in rabbits.

The effect of a partial medial meniscectomy and anterior cruciate ligament (ACL) transection on medial collateral ligament (MCL) healing was studied in skeletally mature rabbits. Two groups of animals, group I (isolated MCL rupture) and group II (MCL rupture with ACL transection and partial medial meniscectomy), were examined. At 6 and 12 weeks postoperatively, histological examination of the healing MCL and biomechanical evaluation of the varus-valgus (V-V) knee rotation and tensile properties of the femur-MCL-tibia complex (FMTC) were performed. Group II animals experienced substantial joint degeneration by 6 weeks. Progressive osteophyte formation was observed adjacent to the MCL insertions along with proximal migration of the MCL tibial insertion between 6 and 12 weeks. Histologic examination of the healing MCL substance from both groups showed disorganized collagen, inflammation, and fibroblast proliferation that decreased over time. For group II knees, the V-V knee rotation was found to be significantly elevated (4.7 to 5.2 times the contralateral control), and did not decrease with time. In contrast, the V-V knee rotations of the group I specimens were 1.8 times greater than control immediately following injury, and approached control values by 12 weeks. Tensile testing of the FMTCs revealed that the ultimate load increased with time for both groups, but group I had significantly higher values than group II. The linear stiffness in group I was not different than that group II and did not increase with time. For the mechanical (material) properties of the healed MCL substance, the modulus of the healing tissue for group II was only 40% that of group I. The structural properties of the FMTC and the mechanical properties of the MCL substance from both groups at 6 and 12 weeks were significantly different from the contralateral controls. We further demonstrated that immediately after ACL reconstruction, the V-V rotation of group II knees could be restored to group I levels. Recent clinical studies of MCL healing following isolated complete ligament tears have suggested that nonoperative management without immobilization leads to excellent treatment outcome. However, in more severe injuries involving additional tissues, poor quality of the healed ligament tissue and articular degeneration are observed. Our results demonstrate the deleterious effects of an untreated triad injury on the healing of the MCL substance and its insertions. Examination of the MCL substance suggests that a much larger healing mass is formed following a triad injury, which partially compensates for inferior ligament mechanical properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗