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Biomedical subjects

D W Jackson

Publications and source records attributed to D W Jackson.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Stress fracture of the ribs in female rowers.

Stress fractures of the lower ribs related to sports are rare. Fractures of the ribs related to rowing sports have not been reported. We have documented seven cases of stress fractures of the lower ribs in female athletes; four were elite rowers and three were engaged in tennis, golf, and gymnastics. Each athlete was initially seen and treated elsewhere for muscular strain. All athletes presented with pain in the posterolateral thorax in and around the scapula. The time from onset of symptoms to diagnosis ranged from 2 to 6 months. Bone scans were used to document the fractures when roentgenograms were equivocal. Each athlete responded to a 4 to 8 week period of rest or training modification. Biomechanical analysis of the forces across the ribs demonstrates that these fractures tend to occur along the posterolateral segment where the bending stresses on the rib are greatest. The predominant muscle forces are generated by the forced couple of scapular retraction and protraction acting through the serratus anterior. We postulate that inadequate strength and resistance training background in women is the cause for the apparent increased susceptibility of women to these skeletal injuries.

Adult↗
PubMedDate not supplied

Freeze dried anterior cruciate ligament allografts. Preliminary studies in a goat model.

One ACL in each of 11 mature goats was replaced with a freeze dried bone-ACL-bone allograft. One year following implantation the goats had their knees evaluated biomechanically and for microvascularity and histologic changes. The reconstructed knees had a significantly greater total AP laxity (3.8 +/- 0.6 mm) (mean and SEM) than the controls (1.0 +/- 0.1 mm). Differences in primary AP laxity were responsible for 81% of the difference in total laxity, with only a 0.4 mm difference in secondary laxity. Neutral stiffness in the reconstructive knee was 17% of control, while stiffness at 30 newtons (N) of anterior force was approximately 50% of controls. Ligament stiffness in the linear region for the ACL allograft was 35% of the control value of 686 N/mm. The maximum load of the allografts was 571 +/- 45 N, or 25% of the contralateral ACL control strength (2301 +/- 155 N). Five of the seven allografts failed at the femoral insertion. Both elongation (83%) and energy (21%) to maximum load were less for allografts than controls. Histologic evaluation of the allografts revealed the presence of a regular oriented dense connective tissue which resembled a normal ligament. Microangiography revealed a periligamentous and endoligamentous vascular pattern reminiscent of a normal ACL and complete revascularization of the bone plugs.

Animals↗
PubMedDate not supplied

Cruciate reconstruction using freeze dried anterior cruciate ligament allograft and a ligament augmentation device (LAD). An experimental study in a goat model.

One ACL in each of 11 mature goats was replaced with a freeze dried bone-ACL-bone allograft and a ligament augmentation device (LAD). The LAD was released from its tibial fixation at 3 months postoperation. Biomechanical, microvascular, and histological changes were evaluated 1 year following implantation. The reconstructed knees had a significantly greater total AP translation (3.1 +/- 0.5 mm) (mean and SEM) than the contralateral controls (1.0 +/- 0.1 mm). Differences in primary AP translation were responsible for 59% of the difference in total translation, with only a 0.6 mm difference in secondary translation. Neutral stiffness in the reconstructive knee was 22% of control, while stiffness at 30 N of anterior force was approximately 35% of controls. Ligament stiffness in the linear region for the ACL allograft/LAD was 53% of the control value of 691 N/mm. The maximum load of the allograft/LADs was 1,052 +/- 145 N, or 43% of the contralateral ACL control strength (2,448 +/- 144 N). Five of the six allografts failed at the femoral insertion. Energy (39%) to maximum load was less for allograft/LADs than controls but elongation to maximum load was the same as control. Histologic evaluation of the allograft/LADs revealed soft tissue cellular ingrowth into the LAD in the extraarticular portions. No bony growth into the LAD was observed. The collagen fibers of the graft appear to be arranged in a longitudinal orientation although some areas show chaotic collagen fibers. Microangiography revealed a periligamentous and endoligamentous vascular pattern reminiscent of a normal ACL and complete revascularization of the bone plugs.

Animals↗
PubMedDate not supplied

Magnetic resonance imaging of the knee.

Magnetic resonance imaging (MRI) is an accepted non-invasive modality for evaluation of soft tissue pathology without exposure to ionizing radiation. Current applications demonstrate excellent visualization of the anatomy and pathology of various organs. Preliminary studies in the knee reveal fine resolution of anatomy and pathology involving the meniscus. The purpose of this study is to determine a prospective correlation between MRI scans and actual meniscal pathology as documented at the time of arthroscopy. MRI scans were obtained in 155 patients, on 156 knees (one patient with bilateral scans), with 86 patients (87 knees) eventually undergoing diagnostic and operative videoarthroscopy performed by the same surgeon (DWJ). All images were obtained on the same high-resolution 1.5 Tesla GE Signa Magnetic Resonance Scanner with the same radiologist performing all readings (PEB). The knees were studied in the coronal and sagittal plane using a spin echo sequence and 5 mm slice thicknesses. The menisci were described as having Grade 1, 2, or 3 changes, with Grade 3 reserved for complete tears. Using arthroscopy as the diagnostic standard, the accuracy of MRI in diagnosing medial and lateral meniscal tears was 93.1% and 96.6%, respectively with a Grade 3 MRI reading. For tears of the ACL, the accuracy was 96.6% as confirmed at arthroscopy. Five tears of the PCL were also documented by MRI and correlated with clinical evaluation. Other abnormalities seen were articular cartilage and osteochondral defects, bone tumors, tibial plateau fractures, Baker's cysts, and meniscal cysts. The MRI scan is a highly accurate, noninvasive modality for documentation of meniscal pathology as well as cruciate ligament tears in the knee.

Arthroscopy↗
PubMedDate not supplied

The effects of processing techniques on the mechanical properties of bone-anterior cruciate ligament-bone allografts. An experimental study in goats.

There has been a growing interest in the use of allografts as ACL substitutes. Allografts are often freeze dried to increase shelf storage time and sterilized with ethylene oxide. This study was conducted to determine the effect of a specific ethylene oxide sterilization procedure and freeze drying process on the initial mechanical properties of femur-ACL-tibia preparations. Twelve knees (stifle joints) from six mature goats were divided into two groups (one knee of pair to each group). Knees were cleaned of all soft tissue except for the anterior cruciate, posterior cruciate, and collateral ligaments. Group 1 was sterilized with ethylene oxide (simulating clean procurement) then freeze dried. Group 2 was freeze dried only (simulating sterile procurement). The knees were rehydrated and then tested in tension to failure to determine their structural mechanical properties. The ethylene oxide-freeze dried specimens (Group 1) had a mean maximum load before failure of 2059 +/- 273 newtons (N) (+/- SE) which was not statistically different than the maximum load of the freeze dried specimens (Group 2) of 2023 +/- 214 N. The average strength of Group 1 and 2 combined was not significantly different than a third group of 12 normal femur-ACL-tibia controls which had an average maximum force of 2403 +/- 133 N. No significant differences between the groups were observed for stiffness, energy to maximum strength, or elongation to maximum force. It appears the freeze dry processing, with or without ethylene oxide sterilization, using the procedure we used, has, at most, a small effect on the initial mechanical properties of the preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

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The effects of cold therapy in the postoperative management of pain in patients undergoing anterior cruciate ligament reconstruction.

This prospective study assessed 54 consecutive arthroscopically assisted ACL reconstructions for the amount of postoperative pain relief provided by cold therapy, using the Hot/Ice Thermal Blanket. Twenty-six randomly selected patients undergoing this procedure were compared to a control group consisting of 28 patients having the identical procedure in which the Hot/Ice unit was not used postoperatively. The initial ACL injury in both groups was sports related with the exception of three patients whose injury occurred while on the job. The Hot/Ice Thermal Blanket consists of two rubber pads (blankets) connected by a hose to the main cooling unit. The pads were applied to either side of the operated knee in the operative suite. The pads received fluid which was circulated from the main unit. The temperature of the fluid was set at 50 degrees in the recovery room and the unit was run continuously until the time of discharge, which was approximately 4 days. Hot/Ice patients required 53% less injectable Demerol and 67% less oral Vistaril than patients in the control group. Hot/Ice patients had made the conversion from injectable to oral pain medication an average of 1.2 days sooner than did their non-Hot/Ice counterparts. There was no appreciable difference in length of hospital stay. Physical therapy and nursing records documented a greater percentage of compliant patients in the Hot/Ice group. According to these records the Hot/Ice patients were more helpful in self-assistance, were out of bed and ambulating in the halls more quickly, and did their range of motion exercises with greater ease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Intraarticular reaction associated with the use of freeze-dried, ethylene oxide-sterilized bone-patella tendon-bone allografts in the reconstruction of the anterior cruciate ligament.

One hundred nine patients over a 3 year period underwent reconstruction for chronic ACL ruptures using a freeze-dried, ethylene oxide-sterilized bone-patella tendon-bone allograft. Seven patients (6.4%) developed a characteristic persistent intraarticular reaction. This reaction was characterized by persistent synovial effusion with collagenous particulates and cellular inflammatory response. Synovial biopsies in all cases showed a similar chronic inflammatory process, characterized by fibrin, collagen, and phagocytic cells. The intraarticular white cells were predominantly lymphocytes. Removal of the allograft resulted in resolution of the reaction in all of the patients. Three of the seven patients showed HLA conversion. Gas chromatography demonstrated detectable levels of ethylene chlorohydrin, a toxic reaction product of ethylene oxide, within the allograft and synovium 14 months following implantation of one graft. These seven cases presented strongly suggest a nonspecific or immune mediated response that must be further delineated. The use of freeze-dried, ethylene oxide-sterilized allografts using standard techniques cannot be recommended for reconstruction of the ACL.

Adolescent↗
PubMedDate not supplied

Nonunion of a first rib fracture in a gymnast.

Isolated fracture of the first rib is uncommon, but has been reported to occur in sports such as basketball, baseball, and dancing. It has not been reported to occur in gymnasts. Usually, these fractures heal with an adequate period of rest. Rarely do first rib fractures become nonunions. They have been felt to be asymptomatic and are usually found incidentally on routine chest roentgenograms. Symptomatic nonunion of a first rib fracture has not been reported previously. Our patient did not respond to nonoperative treatment and required surgical intervention to alleviate her symptoms. We agree that most fractures of this type heal without complications. However, if a persistently symptomatic nonunion ensues, we suggest transaxillary resection of 90% or more of the first rib.

Child↗
PubMedDate not supplied

Spine injuries in gymnasts and swimmers. An epidemiologic investigation.

Three groups of top level female gymnasts of preelite, elite, national and Olympic caliber were studied without regard to back pain or injury. These athletes were compared to a similar group of national caliber female swimmers. Magnetic resonance imaging scans of each participant were used to document disk or bony abnormalities. The relationship between magnetic resonance imaging findings and age, height, weight, previous injuries, back symptoms, and hours of training per week each year was examined. Nine percent of preelite (1/11), 43% of elite (6/14), and 63% of Olympic level (5/8) gymnasts had spine abnormalities; 15.8% of all swimmers had spine abnormalities. Average hours of training per week and age were found to be associated with abnormalities seen on magnetic resonance imaging. Increased intensity and length of training correlated with previous data that suggests the female gymnast is prone to spine injuries.

Adolescent↗
PubMedDate not supplied

The efficacy of continuous passive motion in the rehabilitation of anterior cruciate ligament reconstructions.

Seventy-five patients undergoing arthroscopically-assisted anterior cruciate ligament reconstruction by the same surgeon were divided into three random subgroups. All of the anterior cruciate ligament reconstructions used the middle third of the ipsilateral patellar tendon autograft. Patients undergoing meniscal repair, extraarticular procedures, or repair of other ligaments were excluded. The 75 patients were divided into subgroups to assess the benefits or disadvantages of early active motion (25 patients), continuous passive motion (25 patients), and a combination of both (25 patients) during the first 30 days after surgery. All patients were evaluated at specific intervals for 6 months after surgery. Data recorded included drain output, medication usage, tourniquet time, leg involved, hospital stay length, KT-1000 testing (before surgery in the anesthetized patient, after the procedure was completed, and 2 and 6 months after surgery), and range of motion. Radiographs and the International Knee Evaluation Form were also used to evaluate the results. No statistically significant differences were found between the three groups. Side-to-side anterior-posterior differences, stability, and restoration of full range of motion were similar in each subgroup at each evaluated interval. In this prospective study of motion, started immediately after anterior cruciate ligament reconstruction, passive and active methods were shown to have identical results. A supervised active and passive motion program during the 1st month had the same results as either one used individually.

Adult↗
PubMedDate not supplied

Meniscal transplantation using fresh and cryopreserved allografts. An experimental study in goats.

A comparative study of three subgroups of meniscal transplants was undertaken in the goat model: Group 1 (autograft) involved removal and immediate reimplantation of the meniscus; Group 2, fresh meniscal allografts; and Group 3, cryopreserved (30 days) meniscal allografts. Six months after surgery, tissues were evaluated for gross degenerative changes, proteoglycan concentration (as assessed by uronic acid), water content, vascularity, histology, and cell viability. The contralateral knee served as control for all comparisons. There was no statistical difference in the amount of arthritis present and all transplants demonstrated an essentially normal peripheral vascularity compared to controls. Sections revealed reduced numbers of cells in the central portions of the transplanted menisci and these viable cells demonstrated different behavior in multiplication in tissue culture compared to contralateral controls. Grossly and microscopically, the implanted menisci differed little from the controls. The measurement of proteoglycan concentration and water content of the transplanted meniscal cartilage suggest alterations that may affect the long-term mechanical properties. The autograft specimens showed the water content was very slightly increased (3% to 6%), while the proteoglycan concentration was increased (42% in terms of uronic acid). In contrast, the water content of the fresh allograft group and the cryopreserved group was increased 12% to 24%. Proteoglycan concentration in these groups was decreased up to 56% in portions of some menisci compared to controls. Fresh and cryopreserved meniscal allografts showed peripheral healing, revascularization, cellularity, and incorporation, and grossly appeared good at 6 months in the goat model. The biochemical changes in the extracellular matrix at 6 months raises questions on the long-term function of these transplanted menisci.

Animals↗
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A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat model.

Similar-sized patellar tendon autografts and fresh-frozen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative periods included anterior-posterior translation, mechanical properties determined during tensile failure tests, measurement of cross-sectional area, histology, collagen fibril size and area distribution, and associated articular cartilage degenerative changes. Six months after anterior cruciate ligament reconstruction, the autografts demonstrated a smaller increase in anterior-posterior displacement, values of maximum force to failure two times greater, a significant increase in cross-sectional area, a more rapid loss of large-diameter collagen fibrils, and an increased density and number of small-diameter collagen fibrils compared to the allografts. Clinical significance. More surgeons are allowing their patients to return to running and sports 6 months after anterior cruciate ligament reconstruction. While the structural and material properties of autografts and allografts at time zero are similar, in the goat model during the first 6 months they differ. The allografts demonstrate a greater decrease in their implantation structural properties, a slower rate of biologic incorporation, and the prolonged presence of an inflammatory response. At 6 months the autograft demonstrates a more robust biologic response, improved stability, and increased strength to failure values.

Animals↗
PubMedDate not supplied

Cell survival after transplantation of fresh meniscal allografts. DNA probe analysis in a goat model.

UNLABELLED: Fibrochondrocytes synthesize and maintain the extracellular matrix responsible for the distinctive material and structural properties of a normal meniscus. Viable meniscal cells are believed to be necessary for the long-term maintenance of these properties in meniscal allografts. The purpose of this study was to determine if the donor cells (fibrochondrocytes) survive after a fresh meniscal allograft transplantation. A DNA probe technique was used to clearly distinguish the DNA patterns in donor cells from the host cells in the Spanish goat. No remaining donor DNA could be demonstrated at 4 weeks in transplanted meniscal tissue; it was all of host origin. The host DNA content at 4 weeks approached or exceeded the amount present in the contralateral control meniscus. CLINICAL SIGNIFICANCE: The results of this study demonstrate that viable cells in medial meniscal allografts transplanted from one animal to another do not survive. Host cells rapidly repopulate the transplanted meniscus. There is no evidence these new cells will maintain on a long-term basis the extracellular matrix of the meniscus. The evidence in this paper, that the fibrochondrocytes do not survive transplantation, suggests further justification is necessary for using grafts with living cells. Allografts with living cells have an increased expense, more complicated surgical logistics, and have a higher potential risk of disease transmission.

Animals↗
PubMedDate not supplied

Biologic remodeling after anterior cruciate ligament reconstruction using a collagen matrix derived from demineralized bone. An experimental study in the goat model.

A matrix of demineralized cortical bone was used to reconstruct the anterior cruciate ligament in the goat model. This graft underwent considerable site-specific remodeling and transformation from a Haversian system at time zero into a ligament-like structure at 1 year. This transformation included new bone formation filling the osseous tunnels and replacing the demineralized matrix, development of a ligament-like transition zone within the graft, and ligamentous collagen orientation with crimp in the intraarticular portion of the graft. One year after surgery, the mean anterior-posterior translation in the reconstructed stifle joints at 30 N of tibial loading was 2.1 +/- 0.4 (+/- SEM). The mean ultimate force to failure for the reconstructed ligament at 1 year was 474 +/- 146 N compared with the time-zero (initial) strength of the matrix of 73 +/- 9 N. The cellular repopulation of the graft had no associated inflammatory cells. The potential clinical significance of these findings includes 1) replacement of a collagen matrix with bone within the osseous tunnels, 2) establishment of a more physiologic fibrocartilage transition at the graft insertion site, 3) the time-zero structural properties of a collagen matrix increasing to more desired values with biologic remodeling, and 4) a sterile biologic allograft with essentially no long-term inflammatory response.

Animals↗
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Meniscal repair supplemented with exogenous fibrin clot and autogenous cultured marrow cells in the goat model.

This study was undertaken to evaluate the placement of fibrin clot and cultured autologous marrow cells in surgically created, full-thickness, meniscal lesions in the avascular zone in 32 female Spanish goats. The menisci were repaired with two vertically oriented sutures (N = 8), exogenous fibrin clot was placed into the meniscal defect before placement of the two sutures (N = 8), fibrin clot plus cultured adherent bone marrow cells were placed in the defect (N = 8), or the meniscal lesions were left unrepaired (N = 8). On gross and manual inspection, meniscal lesions showed some degree of healing in all animals except for the eight unrepaired lesions. All the experimental specimens had decreased tensile strength compared with the contralateral control medial menisci. Ultimate load to failure, energy absorbed to failure, and stiffness were less than 40% of the controls for all groups. Histologic sections demonstrated focal cellular areas consisting of giant cells and macrophages in the repair sites. Our observations failed to demonstrate a statistically significant enhancement of healing with the use of exogenous fibrin clot compared with vertically oriented sutures alone. The addition of cultured adherent autologous bone marrow-derived cells in conjunction with the fibrin clot did not enhance the meniscal healing.

Animals↗
PubMedDate not supplied

Iliotibial band syndrome in distance runners.

Iliotibial band syndrome was diagnosed in 48 of 1030 runners treated for lower extremity musculoskeletal complaints. Most athletes had been running 20 to 40 miles a week for one year or longer and had significantly changed their distance, speed, terrain, surface, and/or shoes before the onset of symptoms. Symptoms often persisted for 2 to 6 months. All runners were treated conservatively with rest, stretching, reduced distance, anti-inflammatory medications, local cortisone injections and/or orthoses.

Adolescent↗