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Biomedical subjects

D A McGuire

Publications and source records attributed to D A McGuire.

At least 19 recordsLinked to original sources
PubMed2000

Bioscrew fixation of patellar tendon autografts.

Biodegradable interference screw fixation was studied using patellar tendon autografts in a randomized, prospective multicenter comparison of the PLLA Bioscrew and a metal interference screw. sixty-eight of 114 (60%) patients (34 Bioscrew and 34 metal screw) enrolled were available for follow up an average of 35 months after surgery (range 24-65). There were 42 males and 26 females with an average age of 29 years (16-50). Tourniquet times and associated surgical findings were similar for the two groups. Postoperative KT, Tegner, and Lysholm scores were not statistically different between the two groups. Average follow up KT maximum manual side-to-side difference was 0.9 mm for Bioscrews and 1.4 mm for metal screws. Postoperative Lachman and pivot shift testing were equivalent for the two groups. Other than six of the 7 mm Bioscrews breaking during insertion in the femoral tunnel, there were no problems related to the PLLA implants. No statistical difference was found between the Bioscrew and the metal screw groups, and there were no osteolytic or other reactive bone changes observed associated with the PLLA Bioscrew. These data indicate that the PLLA Bioscrew functions reliably as an interference fixation screw for patellar tendon autografts.

Adolescent↗
PubMed1998

Continuous-flow cold therapy for outpatient anterior cruciate ligament reconstruction.

This prospective, randomized study evaluated continuous-flow cold therapy for postoperative pain in outpatient arthroscopic anterior cruciate ligament (ACL) reconstructions. In group 1, cold therapy was constant for 3 days then as needed in days 4 through 7. Group 2 had no cold therapy. Evaluations and diaries were kept at 1, 2, and 8 hours after surgery, and then daily. Pain was assessed using the VAS and Likert scales. There were 51 cold and 49 noncold patients included. Continuous passive movement (CPM) use averaged 54 hours for cold and 41 hours for noncold groups (P=.003). Prone hangs were done for 192 minutes in the cold group and 151 minutes in the noncold group. Motion at 1 week averaged 5/88 for the cold group and 5/79 the noncold group. The noncold group average visual analog scale (VAS) pain and Likert pain scores were always greater than the cold group. The noncold group average Vicodin use (Knoll, Mt. Olive, NJ) was always greater than the cold group use (P=.001). Continuous-flow cold therapy lowered VAS and Likert scores, reduced Vicodin use, increased prone hangs, CPM, and knee flexion. Continuous-flow cold therapy is safe and effective for outpatient ACL reconstruction reducing pain medication requirements.

Acetaminophen↗
PubMed1998

Arthroscopic Lachman test: a new technique using anatomic references.

Using familiar anatomic references viewed during a standard arthroscopic evaluation, an arthroscopic Lachman test can help the surgeon identify anterior cruciate ligament deficiency. This test is especially useful in those patients where a false-negative report as a result of guarding, meniscal tears or other factors is suspected. Additionally, this test can be used after anterior cruciate ligament reconstruction to verify that the abnormal anterior laxity has been eliminated.

Anterior Cruciate Ligament Injuries↗
PubMed1998

The footprint: a method for checking femoral tunnel placement.

Anterior placement of the femoral tunnel during anterior cruciate ligament reconstruction results in nonisometric placement, and posterior placement can lead to posterior tunnel blow out or troughing. Creating a pretunnel footprint before final placement and drilling allows the surgeon to visually verify that proper femoral tunnel placement has been obtained.

Anterior Cruciate Ligament↗
PubMed1997

The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion.

A retrospective study of arthroscopic anterior cruciate ligament reconstruction in 20 patients was conducted. These patients underwent computed tomography (CT) scans on the involved knee postoperatively to determine sagittal placement of the proximal end of the tibial tunnel (TTp) based on a distance from a specific anatomic reference known as the over-the-back (OTB) ridge. The distance from the posterior aspect of the TTp to the OTB ridge, defined as the backset, was measured from the CT scans. The mean backset was 6.2 mm. The anterior to posterior (AP) tibial plateau diameter was measured from the CT and by plain view radiograph. The mean AP diameter by CT scan was 55.1 mm and the mean AP diameter by radiograph was 55.4 mm. A Pearson correlation coefficient of r = .633 comparing backset versus AP diameter suggests a moderately significant positive relationship. For the AP diameter comparing measurement method, CT versus radiograph, r = .985, representing a highly significant positive relationship, confirming AP diameter sizing accuracy by inexpensive radiography versus CT scan. A proposed backset model based on these data uses three fixed distances, derived by ratio, within a 2-mm range. This model is defined by 5-, 6-, and 7-mm backset intervals for < 50 mm, 50 to 60 mm, and > 60 mm AP diameters respectively, and is currently under prospective clinical investigation.

Adult↗
PubMed1997

Consistent and accurate graft passage and interference screw guide wire placement during single incision anterior cruciate ligament reconstruction.

Misplacement and misalignment of trocar pins and guide wires during single-incision anterior cruciate ligament reconstructions can lead potentially to a number of complications. These complications include unacceptable trocar pin exit locations, difficulty repositioning the trocar pin along the initial track after unsuccessful attempts at graft passage, as well as guide wire impingement and graft transection during interference screw advancement. To help overcome these complications, a surgical technique using an eccentric aimer and two-pin passer was developed to help provide precise and repeatable placement of both a trocar pin and guide wire.

Anterior Cruciate Ligament↗
PubMed1996

Meniscal impingement syndrome.

The meniscal impingement syndrome consists of three elements: impaction on the anterior medial femoral condyle by the leading edge of the medial meniscus, articular cartilage damage of at least Outerbridge grade 3, and knee hyperextension of at least 5 degrees. This report reviews this condition in a series of seven knees with an average follow-up of 39 months. The time from the onset of symptoms until surgery averaged 45 months. Treatment consisted of a thorough arthroscopic knee evaluation and debridement of the articular cartilage fragmentation and any impinging synovitis. Postoperative rehabilitation includes extension block bracing, hamstring strengthening, and closed-chain exercise. With this regimen, there was improvement in the Tegner scores and a reduction in postoperative knee hyperextension. Identification of this uncommon condition requires a complete evaluation of the medial femoral condyle in patients with knee hyperextension.

Adolescent↗
PubMed1996

Is an anterior cruciate ligament reconstruction outcome age dependent?

Treatment of a torn anterior cruciate ligament (ACL) in older patients must be considered in relation to healing delays, rehabilitation difficulties, stiffness, arthritis, and actual athletic demands. This study compares ACL reconstructions in patients 40-years old and older with those under 40-years old and contrasts these to published nonoperative data in the 40 and older patient. Patients undergoing ACL reconstruction between 1992 and 1994 were preoperatively and postoperatively assessed with Lysholm, Tegner, KT, radiographic, and clinical examinations. They were divided into two groups: those 40 years and older (group 1) and those 39 years and younger (group 2). Group 1 had 33 patients with an average age of 44 years (range, 40 to 52 years). Radiographic Fairbank changes were absent. Group 2 had 170 patients with an average age of 27 years (range, 16 to 39 years). Group 1 preoperative instability and intake data were not statistically different from those of group 2. Average follow-up was 21 months for both groups. Both groups showed significant improvement in all parameters at 12- and 24-month follow-up examinations. Lysholm scores, Tegner scores, average KT manual maximum side-to-side differences, Lachman tests, and pivot shift testing were not statistically different in either group. Using Lysholm criteria, in group 1, 89% had excellent/good results, and 11% fair/poor results. This was not statistically different from group 2, which showed 91% excellent/good results and 9% fair/poor results at 24-month follow-up examination. For this age group, nonoperative treatment reports indicate 57% excellent/good results and 43% fair/poor results. The outcomes between these groups are the same and fail to establish the age of 40 years as a barrier to successful ACL reconstruction.

Achilles Tendon↗
PubMed1996

Use of an endoscopic aimer for femoral tunnel placement in anterior cruciate ligament reconstruction.

Accurate placement of the femoral tunnel is a technically difficult aspect of anterior cruciate ligament reconstruction. Various drill guides have been developed to aid in the selection of this site. The purpose of this article is to describe a new drill guide designed to ensure anatomic placement of the femoral tunnel. The guide is used as part of a single-incision arthroscopic anterior cruciate ligament reconstruction technique with a bone-patellar tendon-bone graft secured with interference screws. An intraoperative check of the "pretunnel footprint" can be made to verify correct placement by the remaining cortical margins measurement within an acceptable 1 to 2 mm range before drilling the tunnel to depth. If necessary, minor adjustments to the guidepin location can be made to prevent posterior tunnel margin dimensions of less than 1 mm (troughing) or greater than 2 mm.

Anterior Cruciate Ligament↗
PubMed1995

Preliminary results of an absorbable interference screw.

A randomized, prospective multicenter comparison was done of a bioabsorbable interference screw (Bioscrew; Linvatec Corp, Largo, FL) made from poly L-lactic acid and a metal interference screw produced by the same company. Assignment was randomized by sealed envelopes. A total of 110 patients underwent arthroscopic patellar tendon autografts. A minimum 12 months follow-up is available on 85 patients (mean 19 months, range 12 to 33) including 42 with Bioscrews and 43 with metal screws. There were 56 male and 29 female patients. The average age was 29 years (16 to 50 years). Tourniquet times and associated surgical findings were similar for the two groups. Postoperative Tegner and Lysholm scores were not statistically different between the two groups. KT tests at 1 year showed an average 20-lb laxity of 1.8 mm for the Bioscrew and 1.2 mm for the metal screw groups. The average 1-year KT maximum manual side-to-side difference was 1.6 mm for Bioscrews and 1.6 mm for metal screws. A pivot shift was absent in 83% of Bioscrews and 90% of metal screws at follow-up. Six of 85 Bioscrews inserted (7%) broke on insertion (all were 7-mm diameter screws at the femoral site). No additional fixation was required in four cases. In two, the broken screw was replaced. No lytic bone changes or tunnel widening were found with any Bioscrew. One metal screw had tibial tunnel widening. No statistical difference was found between the Bioscrew and the metal screw groups. Short-term data support the conclusion that the Bioscrew is a reasonable alternative to metal interference screws.

Absorption↗
PubMed1993

Comparison of ketorolac and opioid analgesics in postoperative ACL reconstruction outpatient pain control.

Pain control is an important postoperative consideration with any surgical procedure. Technological and procedural improvements have contributed to the reduction in both the degree of surgical difficulty and the postsurgical complications associated with intricate surgeries. As a result, certain surgeries have potential for being performed on an outpatient basis, dependent upon appropriate pain-management regimens and the degree of potential for postoperative complications. Arthroscopic anterior cruciate ligament (ACL) reconstruction is a common procedure. Because of the reduction in invasiveness that arthroscopy provides, outpatient surgery is now routinely employed for ACL patients. The arguments against ACL outpatient surgery have included the reluctance to use ambulatory, indwelling, intravenous pain-pump delivery systems for opioid pain medication. The purpose of this study was to determine the efficacy of a ketorolac tromethamine used for the management of the postoperative pain produced as a result of outpatient ACL reconstruction. When the ketorolac pain management regimen is compared in this setting with meperidine or morphine, pain control is as good as, or in some cases better than, either of the opioid drugs. Additionally, the adverse side effects associated with opioid drugs are significantly reduced at a substantially lower direct cost to the patient.

Adolescent↗
PubMed1990

Kinematic-based technique for event time determination during gait.

A kinematic-based technique for the estimation of the times at which gait events occur is presented. A kinematic-based model (KM) is defined by the trajectory of a point, which has an anatomically fixed location on the subject's body, about a time at which a measurement system defined gait event takes place. The times at which subsequent occurrences of the gait event takes place are determined by identifying the kinematic pattern that best fits the previously defined KM. The results of an experiment that used the gait patterns of a normal and a pathological walker indicate that the accuracy of the algorithm is limited by the kinematic data sampling interval and that optimal kinematic predictors of gait event times occur within the primary (sagittal) plane of motion. The technique is intended to obviate the need for multiple force plates, instrumented floors and instruments which are worn by the subject for the purpose of determining the times at which gait events occur.

Adult↗
PubMed1989

New technique for acquiring three-dimensional orofacial nonspeech movements.

A new video-based motion analysis system is described that permits acquisition of kinematic patterns from multiple structures (upper lip, lower lip, and jaw), movement patterns to be captured in three dimensions, and acquisition of non-speech orofacial movement patterns without restricting natural head motion. The importance of acquiring three-dimensional lip and jaw movements during nonspeech (e.g., oral opening-closing and chewing motions) movements is emphasized.

Humans↗
PubMed1989

Articular cartilage lesions of the knee.

The pathogenesis and clinical significance of articular cartilage lesions of the knee persist as topics of considerable interest among orthopedic surgeons. This study was designed to assess the association of articular cartilage degeneration with concomitant intraarticular abnormalities and to correlate the prevalence and severity of articular cartilage damage with preoperative historical and physical exam findings in patients presenting with knee pain. Twenty-six history and physical exam data points were prospectively collected from 192 patients (200 knees), consecutively undergoing arthroscopic knee surgery. During surgery, all articular cartilage lesions were recorded with respect to size, location, and character and were graded according to Oglivie-Harris et al. All concomitant knee joint abnormalities were simultaneously recorded. Of 200 knees examined arthroscopically, 12 knees revealed no demonstrable etiology for the presenting symptoms, 65 knees revealed assorted intraarticular pathology but no articular cartilage degeneration, and the remaining 123 knees revealed a total of 211 articular cartilage lesions (103 femoral, 72 patellar, 36 tibial); 7 femoral, 6 patellar and 0 tibial lesions were completely isolated (no concomitant knee joint pathology). The concomitance of femoral defects with tibial lesions was highly significant (p = 0.01). Femoral and tibial articular cartilage lesions were strikingly correlated with the presence of an unstable torn meniscus (p less than 0.001). Medial compartment articular cartilage lesions were significantly more common (p = 0.001), more closely associated with meniscal derangement, and appreciably more severe than lateral compartment lesions. In 75% of anterior cruciate ligament-deficient knees with concomitant articular cartilage degeneration, the duration from injury to surgery was greater than 9 months, and in each of these cases, a history of reinjury to the knee was elicited. From these data one can conclude that: (a) in some patients with painful knees, isolated articular cartilage lesions may be the only abnormality noted at arthroscopy; (b) unstable meniscal tears are significantly associated with destruction of articular cartilage; (c) the medial compartment is particularly susceptible to articular cartilage degeneration; and (d) in our series, anterior cruciate ligament tears were increasingly associated with articular cartilage destruction as the elapsed time from injury to arthroscopy increased.

Adult↗
PubMed1985

Effect of verapamil on pH of ischemic canine myocardium.

Verapamil has been shown to depress the contractility of ischemic myocardium. The present study was designed to determine whether that effect is due to an increase in ischemic injury caused by the drug or whether it might reflect a protective effect. A critical partial occlusion was effected on the left anterior descending coronary artery of 16 open chest foxhounds. A fiberoptic pH probe was implanted in the subendocardium of the ischemic zone, and coronary blood flow was reduced by 79% from a control value of 38 +/- 4 ml/min and held constant. Mean coronary perfusion pressure was decreased 48% from its control value of 90 +/- 6 mm Hg and remained constant. Eight animals were treated with intravenous verapamil, beginning 20 to 30 minutes after the onset of ischemia, in incremental doses (5, 10 and 20 micrograms/kg per min) and eight were treated with placebo. The pH of the ischemic zone increased after institution of treatment in the verapamil group (+ 0.04 +/- 0.05 pH unit) whereas it decreased in the placebo group (- 0.06 +/- 0.4 pH unit) during the first dose (p less than 0.05). Although the difference in pH between the two groups was marked at all doses (p less than 0.03) compared with control partial occlusion, verapamil caused no significant change in heart rate (+ 0.1 +/- 1 beat/min in the verapamil group versus + 0.6 +/- 4.5 beats/min in the placebo group), mean arterial pressure (- 7.5 +/- 4 versus - 4.3 +/- 3 mm Hg, respectively) or cardiac output (- 0.2 +/- 0.07 versus - 0.02 +/- 0.04 liters/min, respectively) comparing control with the first or the second dose of verapamil.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Transmural pH gradient in canine myocardial ischemia.

The subendocardium is more susceptible to ischemia than the subepicardium. Studies during critical coronary stenosis have demonstrated subendocardial hypoperfusion relative to the subepicardium and transmural gradients in certain tissue metabolites. Although ischemia causes acidosis, the existence of a transmural pH gradient has never been demonstrated or quantitated. Thus we reduced coronary blood flow to 20 +/- 5% of normal in eight open chest anesthetized (morphine sulfate and pentobarbital) dogs and to 45 +/- 5% in two dogs. We implanted specially designed miniature fiber-optic pH probes in normal and ischemic subendocardium (depth 5.5-8 mm) and subepicardium (depth 3-4 mm). Separate experiments validated use of the fiber-optic pH probe system to measure tissue pH. Although both probes were located in the ischemic zone, there was a large transmural gradient, i.e., from normal pH values (7.36) in the subepicardium to severely acidotic (pH 6.94) 2 mm deeper in the subendocardium. This marked difference in pH between nearby transmural layers may have important implications regarding arrhythmogenesis in the setting of acute myocardial ischemia.

Animals↗
PubMedDate not supplied

Bioabsorbable interference screws for graft fixation in anterior cruciate ligament reconstruction.

The central one third of the patellar tendon autograft is popular because the bone-tendon-bone (BTB) construct provides several graft fixation options, robust graft incorporation, and a mechanically sufficient substitute. Interference screw fixation is one method used to secure the graft. Bioabsorbable interference screws may offer advantages over metal interference screws. Bioabsorbable screws are made from poly L-lactic acid (PLLA) and are absorbed by the body. This prospective, randomized study compared the safety and efficacy of the PLLA screw with that of the metal cannulated interference screw for anterior cruciate ligament reconstruction. There were 204 patients randomly assigned to the Bioscrew (Linvatec, Largo, FL) (n = 103) or the metal interference screw (n = 101) groups at four sites. The mean age was 30 years. There were 66 women and 138 men. Mean follow-up was 30 months for Bioscrews and 28 months for metal screws; the average follow-up interval was 2.4 years. The Lysholm mean scores at 4 years for the 32 patients seen at this interval were 95.0 and 97.2 for the Bioscrew and metal screw group, respectively. Ligament laxity comparisons made with an instrumented arthrometer at manual maximum force resulted in side-to-side mean score differences of B = 1.8mm and M = 1.6mm. The Tegner activity level score means were B = 6.1 and M = 5.8. Other variables examined included pain, thigh size, meniscal tests, Lachman's test, range of motion, anterior drawer, pivot shift, patellofemoral crepitus and tenderness, and joint effusion. None of these variables showed a statistically significant difference between groups. No radiographic evidence of osteolytic change or bone resorption around the Bioscrews was observed. There were no complications related to loss of fixation, toxicity, allergenicity, or other evidence of osteolytic or inflammatory reaction. In every assessment between groups there was no difference found. There were 12 PLLA screws that broke during insertion without any adverse effects. The PLLA headless cannulated interference fit screws produce equal results to similarly designed metal screws.

Adolescent↗