Biomedical subjects

C T Vangsness

Publications and source records attributed to C T Vangsness.

At least 19 recordsLinked to original sources

PubMed2003

Cultures of ligament fibroblasts in fibrin matrix gel.

The cellular properties of anterior cruciate ligament (ACL) and medial collateral ligament (MCL) fibroblasts have been analyzed in a three-dimensional fibrin matrix gel (FMG) system. The MCL fibroblasts proliferated significantly faster than ACL fibroblasts in 10% fetal bovine serum (FBS). FMG contraction resembles soft-tissue wound contraction. Transforming growth factor-beta1 (TGF-beta1) (5 ng/ml) caused a significantly faster rate of FMG contraction than control (0.5% FBS) in both ACL and MCL fibroblasts. Unlike the cells in 10% FBS, this faster rate of FMG contraction was achieved without increasing the initial cell number. In the FMG, the MCL fibroblasts demonstrated significantly higher collagen synthesis per cell than ACL fibroblasts between the days 2 and 6 of culture. These differences in cellular properties of the ACL and MCL fibroblasts that were observed in vitro may explain the differences in the healing potential of these ligaments in vivo.

Animals↗

PubMed2001

An anatomic study of the supraspinatus muscle and tendon.

The gross and histologic anatomy of the myotendinous portion of the supraspinatus muscle was investigated with coronal and sagittal sections from 20 anatomic specimen shoulders. The anterior lateral portion of the supraspinatus contained more tendon than the posterior portion of the muscle in all 20 specimens. In seven specimens there were separate muscle fibers that originated from the most anteromedial area of the supraspinatus fossa. Knowledge of this anatomy aids in magnetic resonance image interpretation and open or arthroscopic evaluation of the supraspinatus. This consistent tendinous portion may be useful in rotator cuff repair and may provide a firm area for suture closure of the rotator interval. This prominent anterior tendinous area may serve to protect the supraspinatus during anterior forward flexion motion through the impingement arc.

Aged↗

PubMed2000

Electrosurgical methods for arthroscopic meniscectomy: A review of the literature.

PURPOSE: To outline the development of electrosurgical (radiofrequency) devices, explain the basic principles, and review the current orthopaedic literature regarding the application of electrosurgery to arthroscopic partial meniscectomy. MATERIALS AND METHODS: The history and principles of electrosurgery were obtained from various pertinent texts and journal articles. A literature search was performed using MEDLINE; reviewed articles consisted of articles in the English language cataloged between 1966 and January 1999. RESULTS: The history and principles of electrosurgery are reviewed. The articles pertaining to arthroscopic electrosurgical meniscectomy are discussed with a separate discussion on the potential complications of using radiofrequency energy for meniscal ablation, including articular cartilage damage, osteonecrosis, and damage caused by irrigant. CONCLUSION: Electrosurgery has been shown to be an effective tool in arthroscopic meniscectomy. Further research and refinement is warranted because it may show superiority to other methods in certain situations.

Arthroscopy↗

PubMed2000

Management of chronic deep infection following rotator cuff repair.

BACKGROUND: Deep infection of the shoulder following rotator cuff repair is uncommon. There are few reports in the literature regarding the management of such infections. METHODS: We retrospectively reviewed the charts of thirteen patients and recorded the demographic data, clinical and laboratory findings, risk factors, bacteriological findings, and results of surgical management. RESULTS: The average age of the patients was 63.7 years. The interval between the rotator cuff repair and the referral because of infection averaged 9.7 months. An average of 2.4 procedures were performed prior to referral because of infection, and an average of 2.1 procedures were performed at our institution. All patients had pain on presentation, and most had a restricted range of motion. Most patients were afebrile and did not have an elevated white blood-cell count but did have an elevated erythrocyte sedimentation rate. The most common organisms were Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium species. At an average of 3.1 years, all patients were free of infection. Using the Simple Shoulder Test, eight patients stated that the shoulder was comfortable with the arm at rest by the side, they could sleep comfortably, and they were able to perform activities below shoulder level. However, most patients had poor overhead function. CONCLUSIONS: Extensive soft-tissue loss or destruction is associated with a worse prognosis. Extensive débridement, often combined with a muscle transfer, and administration of the appropriate antibiotics controlled the infection, although most patients were left with a substantial deficit in overhead function of the shoulder.

Adult↗

PubMed1999

Overview of treatment options for arthritis in the active patient.

The understanding of arthritis and possible treatment options continues to improve. This article discusses classification of articular cartilage degeneration, osteochondral defects, osteotomy, and a variety of treatments. Developments in the study of growth factors, molecular biology, and gene therapy make the future bright; it is contingent, however, on critical factors such as controlled studies, accurate inclusion criteria, outcome measurement, and long-term follow-up.

Arthritis↗

PubMed1999

Technical pitfalls of meniscal surgery.

Meniscal surgery is one of the most common orthopedic procedures performed today. Orthopedic surgeons must be familiar with the indications for meniscal excision versus repair and comfortable with the diverse instrumentation used for both techniques. Numerous pitfalls exist in diagnosis, indication, and technical aspects of surgery but can be minimized or avoided by careful preoperative planning and attention to detail during the surgical procedure.

Arthroscopes↗

PubMed1999

Extensor carpi radialis brevis. An anatomical analysis of its origin.

We studied the origin of extensor carpi radialis brevis using 40 fresh frozen human cadaver specimens. Ten were stained with haematoxylin and eosin and trichrome which showed the collagenous structure of the extensor tendons at their origin. Gross anatomical observation showed that there was no definitive separation between brevis and communis at the osseotendinous junction. The histological findings confirmed the lack of separation between the two tendons. The extensor tendons were in close proximity to the joint capsule but trichrome staining showed no interdigitation of the tendon with the capsule. The validity of ascribing the pain of lateral epicondylitis to extensor carpi radialis brevis must be questioned. It appears to arise more from the 'common extensor' origin.

Dissection↗

PubMed1999

Cautious surgery for discoid menisci.

This retrospective study reviewed the outcomes of 43 knees in 38 patients with discoid menisci treated from 1977 to 1989. Patients underwent either no treatment, trimming, or subtotal or total resection. Approximately 40% of patients who underwent meniscectomy or partial meniscectomy had a fair or poor rating after an average follow-up of 6.5 years. Pathology demonstrating mucoid fibrinous degeneration within the discoid meniscus was found in many cases, showing abnormal meniscal tissue. Only one third of these knees had symptoms of locking, and only 20 (63%) of 32 had a positive arthrogram, demonstrating the diagnostic difficulties encountered with the discoid meniscus. Patients with a discoid meniscus who are symptomatic should undergo arthroscopy. A partial meniscectomy should be performed to achieve a smooth meniscus and a strong, stable peripheral rim.

Adolescent↗

PubMed1998

Transdermal delivery and accumulation of indomethacin in subcutaneous tissues in rats.

Oral non-steroidal anti-inflammatory drugs (NSAIDs) are effective pharmacotherapy for a wide variety of painful, inflammatory disorders. Development of an efficient means of topical administration of NSAIDs could increase local soft-tissue and joint concentrations while reducing systemic distribution of the drug, thereby reducing side-effects. With this in mind we studied the effects of a novel topical penetration enhancer for lipophilic compounds, a trans-phase delivery system (TPDS), a solution of benzyl alcohol, isopropanol and acetone, on the distribution of indomethacin in various tissues locally and remote from the site of application. We compared the TPDS with a 50:50 (v/v) mixture of propylene glycol and ethanol, a commonly used penetration enhancer, and with oral administration. We found that the TPDS was significantly superior to the other approaches at achieving high local-tissue concentrations in the vicinity of the site of application. In addition, comparison of these two carrier systems seems to clarify the different aqueous and hydrophobic pathways of drug penetration which emerge from various experimental findings and theoretical considerations. Our results suggest that this non-aqueous solvent system, and benzyl alcohol in particular, because of its unique physicochemical and solvating characteristics, might be able to deliver therapeutic levels of indomethacin to tissues close to the site of application in a safer and more effective manner than presently accepted forms of delivery.

Administration, Cutaneous↗

PubMed1998

The treatment of isolated articular cartilage lesions in the young individual.

The treatment of isolated articular cartilage defects is an evolving field in orthopaedic surgery today. We have summarized the basic science and clinical date on the treatment of isolated articular cartilage defects. Further long-term controlled studies are required in order to compare definitively the efficacy of treatments in this difficult clinical area. In future studies, inclusion/exclusion criteria must be detailed, and classification systems need to be standardized Comparative analysis can then be performed to assess the efficacy of various techniques.

Adolescent↗

PubMed1998

The effects of concentric versus eccentric isokinetic strength training of the rotator cuff in the plane of the scapula at various speeds.

This study compares the effects of three modes of isokinetic resistance training at the shoulder--concentric, eccentric, and a combination of both concentric and eccentric, with a group that received no training at all. Twenty-eight healthy volunteers (male and females), 18 to 36 years of age, with no history of shoulder pathology, were randomly assigned to one of four groups; concentric training, eccentric training, a combination of both concentric and eccentric training, or control (no training). Testing and training of the dominant shoulder was performed on an isokinetic dynamometer. All subjects were pretested and post-tested both concentrically and eccentrically for humeral internal/external rotation and abduction at speeds of 60 degrees/sec and 120 degrees/sec. Each training session consisted of a total of twelve sets of ten maximal repetitions, and was repeated three times a week for four weeks. The absolute and percent difference in peak force and peak torque for each group between the pretest and post-test was calculated for each combination of position, mode, and speed. A significant difference between the concentric/eccentric group and the eccentric group was found for abduction (p < 0.05). The eccentric group showed a significantly greater increase from the pretest to post-test for absolute differences in peak force and peak torque compared to the concentric/eccentric group (p < 0.05).

Adolescent↗

PubMed1997

Ablation rates of human meniscal tissue with the Ho:YAG laser: the effects of varying fluences.

To further define the operating parameters for Holmium laser meniscectomy, an in vitro experimental was set up to specifically measure ablation rates and the concomitant thermal injury. Using an experiment set-up with a laser fiber penetrating through meniscal tissue slices, energy levels were varied between 167 and 927 Joules (J)/cm2 per pulse to measure meniscal ablation rates. Following each experiment the adjacent thermal effects were evaluated with hematoxylin and eosin and trichrome staining. The fastest ablation rate was found at 927 J/cm2 per pulse. The increase in ablation rates was directly proportional to the increases in energy levels. Histological examination showed the average lateral thermal change to be 400 to 500 microns, with no demonstrated relation to the pulse level of energy. At these laser parameters the higher levels of energy per pulse showed better ablation of human meniscal tissue without increasing thermal effects in adjacent tissue. Higher energy levels and fluences appeared desirable for more efficient arthroscopic meniscectomy with the Holmium laser.

Humans↗

PubMed1997

Collagen shortening. An experimental approach with heat.

Decreasing joint laxity is a clinical goal of ligament reconstructions. This in vitro study examined the structural and histologic effects of heat shrinkage of human collagen. Two preliminary studies were performed to assess the effect of heat on fresh frozen human tendons obtained from a local tissue bank. As heat was applied to tissue in a saline solution, the percent shrinkage was plotted against temperature. A second study used a freebeam Nd:YAG laser to maximally shrink patellar tendons measuring percent shrinkage versus energy applied. Finally, the effects of 10% shrinkage of fresh frozen human patellar tendons were analyzed mechanically and histologically. Consistent tendon shrinkage curves were found with increasing temperatures in a saline solution. A sharp increase in shrinkage to approximately 70% of resting length was noted around 70 degrees C. Tendon shrinkage by laser induced heat was precise and dose related. Tensile testing of the tendons shortened 10% of their resting length showed a decrease in load to failure to approximately 1/3 compared with that of historical control specimens. Histologic sections showed a well demarcated site of diffuse denaturation and degeneration of collagenous elements. Normal collagen was present adjacent to these thermal changes. These experiments showed that collagen tissue can be shortened precisely by the application of heat. Future studies need to examine the in vivo biologic response of shortened collagen tissue with time, especially recollagenization, restoration of length, and the long term biomechanical effects.

Biomechanical Phenomena↗

PubMed1996

Use of lasers for meniscal repair.

Recent interest in and awareness of laser technology applications have developed in the field of orthopedic surgery. This article presents a review of the literature relevant to the use of lasers for meniscal repair and discusses techniques such as vaporization and removal of tissue using laser heat transfer to tissue as well as laser tissue "welding."

Animals↗

PubMed1995

Pulsed Ho:YAG laser meniscectomy: effect of pulsewidth on tissue penetration rate and lateral thermal damage.

BACKGROUND AND OBJECTIVE: Studies need to define the optimal parameters under which the holmium laser should operate for arthroscopic meniscectomy. This study was designed to analyze the effect of various Holmium wavelength pulsewidths on human meniscal tissue penetration rates and lateral thermal injury. STUDY DESIGN/MATERIALS AND METHODS: Using a pulsed Holmium: YAG laser at a wavelength of 2.1 microns, the effect of various pulse-widths on tissue penetration rates as well as the degree of accompanying thermal damage in human meniscal tissue was evaluated in a specially designed jig. Holding the energy constant at 500 mJ per pulse, the pulsewidth was varied between 100 and 600 microseconds. RESULTS: Fiber penetration of meniscal tissue was found to be fastest at a pulsewidth of 250 microseconds. As the pulsewidth was increased or decreased around this number, the observed penetration time decreased, although no statistical difference was found. The size of the hole created was inversely related to the penetration time. Microscopic examination revealed zones of lateral thermal effect extending 800 microns from the ablation site. CONCLUSION: No relationship between the pulsewidth and the lateral thermal effect could be found.

Adult↗

PubMed1995

Neural anatomy of the glenohumeral ligaments, labrum, and subacromial bursa.

The neural histology of the human shoulder ligaments, glenoid labrum, and subacromial bursae were studied using a modified gold chloride stain. Two morphological types of mechanoreceptors and free nerve endings were found in the ligaments. Slow adapting Ruffini end organs and rapidly adapting Pacinian corpuscles were identified in the superior, middle, inferior, and the posterior glenohumeral ligaments. These specialized proprioceptive nerve endings were also found in the coracoclavicular, and coracoacromial ligaments. Only free nerve endings were found in the glenoid labrum and these were located in the peripheral half. Scattered free nerve endings were found throughout the subacromial bursae. This is the first histological evidence of neural receptors in the human shoulder ligaments, glenoid labrum, and the subacromial bursae. Any disruption of the labrum or these ligaments by trauma or surgery can deprive the shoulder of mechanical stability, and may cause a decrease in proprioception because of the loss of these afferent neural receptors. Removal of symptomatic, inflamed bursae may decrease pain signals from this area of the shoulder.

Adult↗

PubMed1995

Arthroscopic shoulder surgery with three different laser systems: an evaluation of laser applications.

Twelve cadaveric shoulder arthroscopies were performed to evaluate the use of lasers as an adjunctive tool in arthroscopic shoulder surgery. The three most common lasers historically used in orthopedic surgery were examined: Holmium:YAG, Neodymium:YAG, and the CO2. The following parameters were evaluated for each laser system: (1) ease of use of the laser system and handpiece; (2) ability to excise and trim bursae, synovium, ligament, tendon, bone, and articular cartilage; and (3) ability to contract ligaments and capsule by heat transfer. None of these lasers efficiently cut bone, whereas all three systems readily debrided the soft tissues around the shoulder. The free-beam Ho:YAG and CO2 systems heat contracted soft tissues with more control than the contact Nd:YAG. The fiberoptic delivery system of the Neodymium:YAG and Holmium:YAG laser performed well in the saline arthroscopy, and the CO2 delivery system was cumbersome. Overall, the CO2 system removed tissue better than the others, but its difficult use favored the Holmium laser as the best overall current laser system for shoulder arthroscopy.

Aluminum Silicates↗

PubMed1995

In vitro analysis of laser meniscectomy.

Partial meniscectomies were performed on 32 fresh human meniscal autopsy specimens. The following laser systems were tested: carbon dioxide (CO2), neodymium:yttrium aluminum garnet (Nd:YAG), potassium titanyl phosphate (KTP), holmium:YAG (Ho:YAG), and excimer. Meniscectomies with these lasers were compared with scalpel, mechanical, and electrocautery meniscectomies. Lasers were applied to specimens in and out of normal saline. Routine hematoxylin and eosin and sirius red sections were prepared for each specimen, and the depths of thermal changes were analyzed. Scanning electron microscopy was used to visualize the meniscectomy interface. Among these specimens, the scalpel and mechanical meniscectomies showed the least extension of cellular changes (range, 10-15 nm). The excimer laser caused the least tissue changes of the lasers tested. Tissue changes were less extensive with the pulsed CO2 laser than with the holmium:YAG, neodymium:YAG, and KTP lasers. Scanning electron microscopy showed that use of the scalpel meniscectomy resulted in the smoothest meniscectomy edge, followed by use of the excimer, CO2, holmium:YAG, neodymium:YAG, and KTP lasers. The most surface disruption occurred with electrocautery. Meniscectomies under saline required more energy and took longer in each case, with the holmium:YAG, neodymium:YAG, and CO2 laser cutting the best. Saline meniscectomies showed less thermal change. The CO2 and KTP lasers cut best in air.

Adult↗