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D W Jackson

Publications and source records attributed to D W Jackson.

At least 19 recordsLinked to original sources
PubMed1992

The correlation between anterior-posterior translation and cross-sectional area of anterior cruciate ligament reconstructions.

Total anterior-posterior translation is commonly used to assess the integrity of the cruciate ligaments and the success of reconstructive surgery. The purpose of this study was to determine, after surgical reconstruction of the anterior cruciate ligament with a biological graft, if total anterior-posterior translation correlated with graft length, cross-sectional area, or mechanical properties. These factors were investigated by analyzing data from three previous studies. These studies involved replacement of the anterior cruciate ligament in cynomolgus monkeys and goats, with free and vascularized patellar tendon autografts and both patellar tendon and anterior cruciate ligament allografts. Data were available at time periods of 6 and 12 months after surgery. We found statistically significant inverse correlations between the amount of anterior-posterior translation and cross-sectional area of a graft at the time of sacrifice. The Pearson correlation coefficients ranged from -0.966 (p < 0.002) to -0.830 (p < 0.05). We hypothesize that these correlations result from the following mechanism: the increased anterior translation reflects a slack graft; a slack graft is stress shielded by other structures about the knee; the reduced in vivo stresses on the graft modulate cellular metabolism in a way that over time produces a small cross-sectional area.

Analysis of Variance↗
PubMed1992

The biomechanical effects of geometric configuration of bone-tendon-bone autografts in anterior cruciate ligament reconstruction.

This study provides biomechanical support for a new technique of autograft anterior cruciate ligament reconstruction featuring circular bone plugs and endosteal interference fit fixation. Six matched pairs of fresh frozen human knees were utilized. Femoral interference fit pull-out strength was determined from material-testing-machine-generated oscillograph recordings at a strain rate of 100%/s. Circular bone plugs, obtained with a circular oscillating saw, provided 19.9% greater interference fit pull-out strength compared with identically fixed trapezoidal bone plugs. Different geometric defects were compared in three- and four-point bending on an Instron machine with frozen patellae and an artificial bone composite. Circular defects have 107% greater strength than matched trapezoidal patellar defects in three-point bending. In a bone composite, circular defects are 53% stronger than triangular and 25% stronger in four-point bending than trapezoidal defects. A new technique of harvesting bone plugs with endosteal interference fit fixation is described and biomechanically supported. To date, this technique has been performed on over 500 cases clinically without evidence of patellar fracture or fixation failure. This study demonstrates the efficacy of this simple and reproducible technique compared with previously reported procedures.

Aged↗
PubMed1992

Videoarthroscopy: review and state of the art.

Since the introduction of videoarthroscopy, there has been rapid technological advancement. The charged couple device (CCD) has become the standard small pickup unit for the present cameras. The video signal processing and transfer has been modified and improved. New Y/C or super VHS and red, green, blue (RGB) systems have been associated with improvements in monitors, video recorders, and video printers. Measurements of video quality such as resolution, signal-to-noise ratio, pixels, and contrast have been confusing to clinicians evaluating these new systems. Equipment compatibility and the weak-link theory is important to understand when selecting new equipment. This review article presents an update for the clinician who wants more information to differentiate among the new video arthroscopic systems.

Arthroscopy↗
PubMed1992

Office arthroscopy: a diagnostic alternative.

Twenty patients with enigmatic knee symptoms were selected for evaluation by both magnetic resonance imaging (MRI) and office arthroscopy. Office arthroscopy was performed in a standard examination room using a miniature (1.7 mm) fiberoptic arthroscope under local anesthesia. All MRI scans were performed on a state-of-the-art 1.5-T magnet unit, and included specialized cartilage sequences in 7 patients. In 14 patients, 26 areas showed articular cartilage changes by arthroscopy (grade 2-3). Only nine of these areas were detected by MRI (sensitivity 34.6%). There were five false-positive and four false-negative readings of meniscal tears by MRI as compared with office arthroscopy. These results improved when postoperative menisci were excluded. Only one of three anterior cruciate ligament (ACL) disruptions identified by MRI could be verified by arthroscopy. The one posterior cruciate ligament (PCL) disruption was confirmed by both techniques. MRI was superior to arthroscopy in identifying bone contusions, subchondral sclerosis, and medial cruciate ligament (MCL) sprains. Office arthroscopy is an accurate and cost-efficient alternative to MRI in diagnostic evaluation of knee pathology in patients with enigmatic symptomatology.

Adolescent↗
PubMed1992

Survival of cells after intra-articular transplantation of fresh allografts of the patellar and anterior cruciate ligaments. DNA-probe analysis in a goat model.

The fate of donor cells in fresh allografts of the patellar and anterior cruciate ligaments was assessed after transplantation of the allografts as substitutes for the anterior cruciate ligament in goats. DNA-probe analysis was used to distinguish between the DNA of individual goats. Donor DNA was completely replaced by recipient DNA in both the transplanted patellar and anterior cruciate ligaments within a four-week period. Simultaneous full-thickness skin transplants in the same animals were not rejected during the interval of rapid loss of donor DNA from the allografts. The absence of rejection of the skin grafts at the one-week interval suggests that no pre-existing antibody associated with an immune reaction was responsible for the rapid loss of DNA in the allografts.

Animals↗
PubMed1991

Occult osseous lesions documented by magnetic resonance imaging associated with anterior cruciate ligament ruptures.

Magnetic resonance images (MRI) were performed within three weeks of anterior cruciate ligament (ACL) rupture on 75 skeletally mature patients. Occult bony lesions were documented in 64 (85%) of the patients. Of the 64 patients with bone injuries, 83% had lesions of the lateral compartment. The lateral femoral condyle was involved in 50%, and the lateral tibial plateau was injured in 50% of the patients with changes. Nineteen of the 64 patients had more than one area of bony injury. Although the majority of bony lesions resolve, permanent alterations remained in some cases. This study has implications that may affect rehabilitation and the long-term prognosis in those patients with extensive bony and associated articular cartilage injuries.

Adult↗
PubMed1991

Recurrent dislocation of the proximal tibiofibular joint.

Recurrent dislocation of the proximal tibiofibular joint is a rare injury. This report presents a case of bilateral recurrent dislocations of the proximal tibiofibular joint in a jet skier that responded to physical therapy and activity modification. A review of the literature is provided, with attention to the mechanism of injury and other treatment options--including arthrodesis and resection of the proximal fibula. This diagnosis should be considered in jet skiers with lateral-sided knee pain.

Adult↗
PubMed1991

The effects of in situ freezing on the anterior cruciate ligament. An experimental study in goats.

We developed an in situ freeze-thaw model designed to simulate an ideally placed and oriented autogenous graft of the anterior cruciate ligament. In this model, the anterior cruciate ligament was exposed, and the femoral insertion, tibial insertion, and body of the anterior cruciate ligament were frozen in situ with specially designed freezing probes. Freeze-thaw cycles were repeated five times. We used the technique in thirty-three mature goats to study the biological and biomechanical outcomes of the devitalized and devascularized anterior cruciate ligament at zero, six, and twenty-six weeks after treatment. Thus, the collagen fibers of the simulated autogenous graft remain in normal anatomical position and the simulated graft is fixed under physiological tension. At twenty-six weeks, no statistically significant differences were noted between treated and contralateral control (untreated) ligaments relative to anterior-posterior translation, maximum force to rupture, stiffness in the linear region of the force-length curve, modulus of elasticity in the linear region, strain to maximum stress, or maximum stress. The only statistically significant difference was an increase in cross-sectional area of the ligament. This increase was 22 and 42 per cent greater than that in the control ligaments at six weeks and six months. At six months, the ligaments in the control group had an average mid-cross-sectional area of 17.7 +/- 1.2 square millimeters and the ligaments in the experimental group, 25.2 +/- 3.1 square millimeters. Changes in the size and density of the collagen fibrils also were demonstrated at six months. These observations are in sharp contrast to our previous studies of replacement of the anterior cruciate ligament, in which an allograft of the ligament or an allograft supplemented with a 3M ligament augmentation device (LAD; 3M, St. Paul, Minnesota) was used. In those studies, an average reduction in maximum strength of 75 per cent for the allografts and 50 per cent for the allografts that had a ligament-augmentation device was found at one year. We concluded that devitalized, devascularized anterior cruciate ligaments do not lose strength if the anatomical position and the orientation of the collagen fibers are not altered.

Animals↗
PubMed1990

Cyclops syndrome: loss of extension following intra-articular anterior cruciate ligament reconstruction.

Arthrofibrosis is one of the recognized complications following traditional anterior cruciate ligament (ACL) reconstruction. With the advent of arthroscopic assisted ACL reconstructions, the extent of potential arthrofibrosis appeared to be less. However, 13 patients after intra-articular ACL reconstruction using a patella tendon autograft developed a similar symptom complex. In addition to postoperative loss of full extension, there was an audible and palpable clunk with terminal extension. These patients had similar arthroscopic findings of a nodule that formed anterolateral to the tibial tunnel placement of the graft. The arthroscopic appearance of the soft tissue mass with its surface vessels was reminiscent of a "cyclops." After arthroscopy with debridement and manipulation of the knee, extension was improved in all cases. The average range of motion immediately after the procedure was 6.0-130 degrees, compared with 16-103 degrees preoperatively. The range of motion at last follow-up averaged 3.8 degrees of extension and 138 degrees of flexion. All patients had greater than 130 degrees of flexion. There were no complications attributed to the manipulation and arthroscopic lysis of adhesions, and no patient experienced loss of graft integrity or knee stability. The "cyclops" nodule was examined grossly and microscopically and demonstrated peripheral fibrous tissue with a central region of granulation tissue in all specimens. In addition, two specimens were noted to include bony fragments and three specimens contained cartilaginous tissue.

Adult↗
PubMed1990

Estimation of fetal weight by means of ultrasound: a comparison of methods.

An accurate prediction of birth weight during gestation can provide useful information for assessing fetal and newborn health status, enabling the clinician to better predict infant morbidity and mortality. Two previously reported standard methods for birth-weight estimation used data collected in utero to derive formulas by least-squares linear regression. The rationale for the inclusion of particular variables in these equations, however, has not been clearly defined. This study was undertaken to examine the efficacy of some previously used variables as well as some new variables in estimating fetal birth weight. The authors used measurements of femur length, biparietal diameter, and abdominal circumference from 107 fetuses (2500 to 4000 g) as variables to compare the two standard methods of birth-weight estimation. A new formula is presented that is derived from a simple model based on the known relationship between volume and weight. The head is represented as a sphere and the body as a cylinder. This study presents a more systematic approach to formula development in which statistical biases are minimized by examining the underlying distributions of the variables used to predict birth weight.

Birth Weight↗
PubMed1989

Osteochondritis in the female gymnast's elbow.

Ten cases of osteochondritis dissecans of the humeral capitellum are reviewed in seven high-performance female gymnasts, ranging in age from 10 to 17 years old. All but one were evaluated and treated with arthroscopy and/or arthrotomy, with curettage of loose articular margins, drilling of the lesion, and removal of loose bodies. The average length of follow-up is 2.9 years, and includes interview, physical examination, and roentgenographic evaluation. This injury has been previously described in relation to compressive forces across the radiocapitellar joint from repetitive valgus loading in a developing epiphysis. Only one of the athletes, at the time of follow-up, was still in competitive gymnastics. Each has a minimal limitation in range of motion, with crepitus and often catching noted by history and on examination. These cases double the limited literature on this injury in young, female gymnasts. They stimulate concern for the proper and early evaluation and treatment of elbow injuries in this at risk group. Once the bony changes in the capitellum are detected, and pain remains despite conservative management, we have found that symptoms can be improved with surgery, but persist in female gymnasts. Our experience in this more-advanced group is that the return to high-level competitive gymnastics is unlikely.

Adolescent↗
PubMed1989

MRI demonstration of radiographically occult fractures: what have we been missing?

During the course of MRI examinations of the knee for possible internal derangement, the hip for avascular necrosis, and the shoulder for rotator cuff tears, we have encountered many examples of unsuspected fractures of the tibial plateau, femoral condyles, pelvis, hip and proximal humerus. These fractures were either radiographically inapparent or demonstrated very subtle abnormalities that were missed on prospective interpretation. In addition, a large number of patients have been found to demonstrate evidence of intraosseous trabecular disruption, or edema and hemorrhage of medullary bone, or stress type injuries, all of which are radiographically occult. The clinical significance of these osseous abnormalities varies and is dependent upon the degree of injury. It is believed that an awareness of these osseous abnormalities will improve the accuracy of MRI interpretation, will heighten an appreciation of the subtle radiographic abnormalities that may be present, and will improve patient evaluation and management.

Adult↗
PubMed1988

Arthroscopically assisted reconstruction of the anterior cruciate ligament using a patella tendon bone autograft.

Techniques for anterior cruciate ligament (ACL) surgery have evolved from the traditional open procedures to arthroscopically assisted procedures. The rationale for arthroscopically assisted ACL reconstruction includes small incisions, no disruption of the extensor mechanism, shorter hospitalizations, reduced postoperative pain, and faster rehabilitation. A stepwise approach for ACL reconstructions is presented.

Arthroplasty↗
PubMed1988

Considerations in total knee arthroplasty following previous knee fusion.

Two patients who were dissatisfied with the functional results of knee fusion had conversion to total knee arthroplasty at one and 16 years following previously solid fusion. Both patients were over 65 years of age. Unconstrained prosthetic components were used and no special soft tissue stabilizing procedures were needed. At follow-up examinations, five and one-half and three years postoperatively, the results have been gratifying with good stability and adequate range of motion from 0 degrees to 90 degrees of flexion. Both patients were able to walk and climb stairs without support. The patients claimed that quality of function was significantly improved. Whenever possible, fusion of the knee in young people should be done so that this option remains open in later life. Arthrodesis is advised in young patients to allow for possibility of revision to total knee arthroplasty at a later date as technology improves.

Aged↗
PubMed1987

Using a monoclonal antibody to identify patients with type I and type II von Willebrand's disease.

Three monoclonal antibodies produced against vWF:Ag by conventional hybridoma technique did not inhibit factor VIII coagulant activity (F. VIII:C) but did inhibit VIII ristocetin cofactor activity. The antibodies were used in an indirect competitive ELISA for quantifying von Willebrand's antigen (vWF:Ag) and compared with values obtained by the Laurell technique using commercial antibody by means of a ratio: ELISA/Laurell. For one monoclonal BD2-CC9, vWF:Ag values obtained in the two assays were in good agreement for normal and hemophilia A plasmas (normal, n = 19, ratio = 1.13 +/- .17, hemophilia A, n = 10, ratio = 0.91 +/- .15). However, type II vWD patients had a disproportionately low value of vWF:Ag with the ELISA. Use of the ratio normalized the difference among individual plasma values and allowed a significant separation of type II vWD plasma (n = 9, ratio = 0.46 +/- .19) from normal plasma (p = .0001) and type I vWD plasma (n = 8, ratio = 1.52 +/- .34) from type II vWD plasma (p = .0003) using BD2-CC9. Although the sample size was small, the greater degree of discrimination among the vWD plasmas tested with BD2-CC9 (compared with the other two antibodies [CA3-AE4, CC6-BG10]) suggests that this antibody may recognize conformational epitopes that reflect the degree of multimeric polymerization of the vWF molecule rather than simply recognize a decreased number of antigenic sites in a basic subunit. BD2-CC9 may be valuable in investigating the various types of vWD and/or the process of polymerization of this complex protein.

Antibodies, Monoclonal↗
PubMed1987

Arthroscopic anterior cruciate ligament reconstruction.

Our understanding of the structure and function of the anterior cruciate ligament has progressed rapidly over the past decade. Arthroscope-assisted anterior cruciate ligament replacement is a new procedure that allows isometric placement of the anterior cruciate ligament graft. Postoperative rehabilitation is enhanced by preservation of the extensor mechanism.

Arthroscopy↗