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Biomedical subjects

Brian J Cole

Publications and source records attributed to Brian J Cole.

At least 19 recordsLinked to original sources
PubMed2006

Effect of lateral meniscus allograft on shoulder articular contact areas and pressures.

The objective of this study was to determine the effect of a lateral meniscus allograft on the articular contact area and pressures across the glenohumeral joint under compressive loads of 220 N and 440 N. Eight fresh-frozen shoulders were used, and contact areas and pressures were determined with a Tekscan flexible tactile force sensor. Testing conditions included a normal glenohumeral joint and one interposed with a lateral meniscus allograft. Using the Tekscan sensing equipment, we evaluated the total force (in Newtons), contact area (in square millimeters), mean contact pressure (in kilograms per square centimeter), peak force (in Newtons), and peak contact pressure (in kilograms per square centimeter). The interposed lateral meniscus allograft group showed a statistically significant decrease in total force at both 220 N and 440 N, as well as a decrease in contact area for the 220-N testing condition. There were no statistically significant differences between the two groups in contact area at 440 N or in peak forces or peak contact areas for either 220-N or 440-N testing condition. Biomechanically biologic resurfacing with a lateral meniscus allograft of the glenohumeral joint is supported by decreased forces on the glenoid surface.

Adult↗
PubMed2006

Biocompatibility of a polymer patch for rotator cuff repair.

Both mechanical and biological factors influence the high re-tear rate after rotator cuff repair. Mechanical factors have largely been addressed by the introduction of better implants and modification of suture configuration, but further improvements are needed to address the often poor tissue quality of the degenerated rotator cuff tendons. Current biological solutions provide only short-term reinforcement and have been associated with pseudo-infectious reactions. This pre-clinical animal study investigates the biological response to a novel polycarbonate polyurethane patch used for tissue augmentation in a rat rotator cuff repair model. Bilateral defects were created in the supraspinatus tendons of 12 Sprague Dawley rats. One side was repaired with a patch as a tissue augmentation device. The contralateral side acted as internal control without patch augmentation. After 6 weeks the tissues were harvested and underwent histologic and histomorphometric analyses. Histological evaluation demonstrated no inflammatory reaction; histomorphometry revealed tissue ingrowth of 79.9%. In conclusion, the polycarbonate polyurethane patch for tissue extension or augmentation in rotator cuff repair has demonstrated no inflammatory response and excellent tissue integration in a rat rotator cuff repair model.

Animals↗
PubMed2006

Tibiofemoral contact mechanics after serial medial meniscectomies in the human cadaveric knee.

BACKGROUND: There is no consensus regarding the extent of meniscectomy leading to deleterious effects on tibiofemoral contact mechanics. HYPOTHESIS: The meniscus aids in optimizing tibiofemoral contact mechanics, increasing contact area, and decreasing contact stress. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen human cadaveric knees each underwent 15 separate testing conditions-5 serial 20-mm posterior medial meniscectomy conditions (intact, 50% radial width, 75% radial width, segmental, and total meniscectomy) at 3 flexion angles (0 degrees , 30 degrees , and 60 degrees )-under an 1800-N axial load. Tekscan sensors were used to measure total force and medial force, contact area, mean contact stress, and peak contact stress. RESULTS: All posterior medial meniscectomy conditions resulted in significantly decreased contact areas and increased mean and peak contact stresses compared with the intact state (P < .05). The changes in contact mechanics after segmental and total posterior medial meniscectomies were not statistically different (P > .05). Incremental changes in contact area and mean contact stress increased as more peripheral portions of the medial meniscus were removed, whereas peak contact stresses exhibited similar incremental changes throughout all meniscectomy conditions. CONCLUSIONS: The meniscus is a crucial load-bearing structure, optimizing contact area and minimizing contact stress. Loss of hoop tension (ie, segmental meniscectomy) is equivalent to total meniscectomy in load-bearing terms. The peripheral portion of the medial meniscus provides a greater contribution to increasing contact areas and decreasing mean contact stresses than does the central portion, whereas peak contact stresses increase proportionally to the amount of meniscus removed. CLINICAL RELEVANCE: Because the degree of meniscectomy leading to clinically significant outcomes is unknown, a prudent strategy is to preserve the greatest amount of meniscus possible.

Adult↗
PubMed2006

Prospective evaluation of allograft meniscus transplantation: a minimum 2-year follow-up.

BACKGROUND: Clinical and biomechanical studies have demonstrated the increase in contact pressure and progressive deterioration of the tibiofemoral compartments that occur after partial or complete meniscectomy. Meniscus transplantation has been indicated for the symptomatic postmeniscectomy patient to alleviate symptoms and potentially prevent the progression of articular degeneration. PURPOSE: To report the early-term results after allograft meniscus transplantations from a single institution performed by a single surgeon. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Forty-four meniscus transplants in 39 patients were evaluated at minimum 2-year follow-up using the Lysholm, Tegner, International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score, Noyes symptom rating and sports activity, and SF-12 scoring systems; visual analog pain scales; patient satisfaction; and physical examination. Four transplants failed early, leaving 40 transplants in 36 patients for review. Patients were grouped into medial and lateral transplant groups as well as those with isolated and combined procedures. Twenty-one menisci were transplanted in isolation (52.5%), and 19 were combined with other procedures (47.5%) to address concomitant articular cartilage injury. RESULTS: Patients demonstrated statistically significant improvements in standardized outcomes surveys and visual analog pain and satisfaction scales. In 7 patients, treatment had failed at final follow-up. Overall, 77.5% of patients reported they were completely or mostly satisfied with the procedure, and 90% of patients were classified as normal or nearly normal using the International Knee Documentation Committee knee examination score at final follow-up. There were no significant differences in the medial and lateral subgroups, although the lateral subgroup did demonstrate a trend toward greater improvement. No significant differences were noted in the isolated and combined subgroups. CONCLUSION: Meniscus transplantation alone or in combination with other reconstructive procedures results in reliable improvements in knee pain and function at minimum 2-year follow-up. Longer term studies are necessary to determine if transplantation can prevent the articular degeneration associated with meniscectomy.

Adolescent↗
PubMed2006

Minced cartilage without cell culture serves as an effective intraoperative cell source for cartilage repair.

Traumatic articular cartilage injuries heal poorly and may predispose patients to the early onset of osteoarthritis. One current treatment relies on surgical delivery of autologous chondrocytes that are prepared, prior to implantation, through ex vivo cell expansion of cartilage biopsy cells. The requirement for cell expansion, however, is both complex and expensive and has proven to be a major hurdle in achieving a widespread adoption of the treatment. This study presents evidence that autologous chondrocyte implantation can be delivered without requiring ex vivo cell expansion. The proposed improvement relies on mechanical fragmentation of cartilage tissue sufficient to mobilize embedded chondrocytes via increased tissue surface area. Our outgrowth study, which was used to demonstrate chondrocyte migration and growth, indicated that fragmented cartilage tissue is a rich source for chondrocyte redistribution. The chondrocytes outgrown into 3-D scaffolds also formed cartilage-like tissue when implanted in SCID mice. Direct treatment of full-thickness chondral defects in goats using cartilage fragments on a resorbable scaffold produced hyaline-like repair tissue at 6 months. Thus, delivery of chondrocytes in the form of cartilage tissue fragments in conjunction with appropriate polymeric scaffolds provides a novel intraoperative approach for cell-based cartilage repair.

Animals↗
PubMed2006

The accessory posteromedial portal revisited: utility for arthroscopic rotator cuff repair.

Arthroscopic rotator cuff repair is a technically challenging procedure. Accessory arthroscopic portals have been described that allow for optimal suture anchor placement, suture management, and knot tying. We describe here the usefulness of an accessory posteromedial portal that facilitates direct suture retrieval through the posterior aspect of a rotator cuff tear. This portal is created approximately 4 to 5 cm medial to the posterolateral corner of the acromion and 2 cm inferior to the scapular spine. The accessory posteromedial portal is especially useful when a retracted tear of the infraspinatus or teres minor is encountered. Because these tendons retract in a posterior and medial direction, the accessory posteromedial portal places the tendon-penetrating device in an ideal position for suture passage through the posterior portion of the rotator cuff tear. This portal also allows placement of margin convergence sutures for large U-shaped or L-shaped tears by permitting a direct "hand-off" of the suture to or from a second penetrating device that is placed through a standard anterior portal. If multiple suture anchors are required (as in the case of large or massive cuff tears, or when double-row fixation is employed), sutures can be pulled out through the accessory posteromedial portal to facilitate suture management.

Arthroscopy↗
PubMed2006

Chondrolysis after continuous intra-articular bupivacaine infusion: an experimental model investigating chondrotoxicity in the rabbit shoulder.

PURPOSE: Postoperative pain pumps are increasingly used to deliver a continuous infusion of local anesthetic into the surgical wound or the joint. Recently, there have been concerns that the use of such devices may be associated with chondrotoxicity and even cases of chondrolysis in the shoulder. An experimental model is presented that investigates potential chondrotoxic effects of a continuous intra-articular infusion of bupivacaine in the rabbit shoulder. METHODS: We divided 30 rabbits into 3 groups that received continuous infusions of either saline solution, bupivacaine, or bupivacaine with epinephrine into the glenohumeral joint over a period of 48 hours. Animals were killed after 1 week, and osteochondral and synovial samples from the glenohumeral joint underwent analyses with confocal microscopy for live/dead cell assay, metabolic sulfate uptake assessment, and conventional histologic analysis. RESULTS: Infusion of bupivacaine with epinephrine and without epinephrine decreased sulfate uptake by 56% (P = .009) and 50% (P = .02), respectively, when compared with saline solution; cell viability decreased by 20% (P = .08) and 32% (P = .02), respectively. Histologic analysis yielded significantly worse scores for bupivacaine infusion with epinephrine (P = .004) and without epinephrine (P = .02). The results for bupivacaine with or without epinephrine were not significantly different. CONCLUSIONS: Continuous intra-articular infusion of bupivacaine with and without epinephrine led to significant histopathologic and metabolic changes in articular cartilage. CLINICAL RELEVANCE: Bupivacaine showed profound chondrotoxic effects in an experimental model that closely followed the current clinical application of postoperative pain pumps. The results caution against the use of such devices in applications for smaller joints with minimal clearance or dilution as a result of hematoma, where continuous exposure of cartilage to bupivacaine is expected.

Analgesia, Patient-Controlled↗
PubMed2006

Treatment of chondral defects in the patellofemoral joint.

Patellofemoral disease is one of the most controversial management issues in orthopedic surgery. Nonoperative management as a prerequisite first line treatment is successful in the majority of cases. However, a small subset of patients with persistent pain after adequate rehabilitation will be potential candidates for surgical intervention. Careful assessment of the underlying pathomechanics is critical for a successful outcome; these include malalignment of the extensor mechanism, trochlear dysplasia, soft-tissue imbalance, and chondral damage. As the pathology is multifactorial, the planning and treatment must be multifaceted. With careful patient selection, the options of titrated limited lateral release, restoration of MPFL function, tibial tubercle osteotomy, cartilage repair, and patellofemoral resurfacing provide improved functionality and pain relief for the young patient suffering from patellofemoral pain.

Algorithms↗
PubMed2006

Basic science and treatment options for articular cartilage injuries.

Articular cartilage injuries can produce significant musculoskeletal morbidity for both young and active aging patient populations. The complex and highly specialized composition of normal hyaline cartilage makes treatment of focal chondral injuries a formidable challenge for the basic scientist, surgeon, and physical therapist. The current array of surgical treatment options offers palliative, reparative, and restorative treatment strategies. Palliative options include simple arthroscopic debridement. Reparative strategies utilize marrow stimulation techniques to induce formation of fibrocartilage within the chondral defect. Restorative tactics attempt to replace damaged cartilage with hyaline or hyaline-like tissue using osteochondral or chondrocyte transplantation. Furthermore, while treatment success is obviously dependent on good surgical selection and technique, the importance of sound, compliant postoperative rehabilitation cannot be understated. The purpose of this article is to review the basic science of articular cartilage, current treatment options available, and outline the clinical decision making involved when using these procedures by presenting the algorithm used at our institution for treating focal cartilage lesions.

Arthroplasty↗
PubMed2005

Trochlear contact pressures after anteromedialization of the tibial tubercle.

BACKGROUND: Anteromedialization is recommended for cartilage restoration of patellofemoral defects, with the presumption that it decreases contact pressures across the trochlea. No study has evaluated pressures on the trochlear side of the patellofemoral joint after anteromedialization of the tibial tubercle. HYPOTHESIS: Anteromedialization of the tibial tubercle decreases contact pressure across the trochlea. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric knees were tested by placing an electroresistive pressure sensor on the femoral side of the patellofemoral joint. A validated model of nonweightbearing resisted extension was simulated by loading the extensor mechanism at 89.1 N and 178.2 N. Knees were tested 3 times per load at 30 degrees , 60 degrees , 90 degrees , and 105 degrees . The center of force and pressure across the patellofemoral articulation were compared before and after a reproducible and consistent anteromedialization. RESULTS: The mean center of force shifted medially after anteromedialization at 89.1 N and 178.2 N. At 89.1 N, the mean total contact pressure decreased significantly (P < .05) at all angles, and at 178.2 N, it decreased significantly at 30 degrees , 60 degrees , and 90 degrees of knee flexion. The mean lateral trochlear contact pressure decreased significantly (P < .05) at all flexion angles at both 89.1 N and 178.2 N. The mean central trochlear contact pressure decreased significantly (P < .05) at 30 degrees with the 89.1-N and 178.2-N loads but increased significantly (P < .05) at 90 degrees with the 89.1-N load. The mean medial trochlear contact pressure increased significantly (P < .05) at all flexion angles at 89.1 N and 178.2 N. CONCLUSION: Anteromedialization shifts the contact force to the medial trochlea and decreases the mean total contact pressure. CLINICAL RELEVANCE: Anteromedialization decreases the mean total contact pressure while shifting contact pressure toward the medial trochlea. This study suggests that anteromedialization is appropriate for unloading the lateral trochlea. However, this procedure appears to have minimal benefit on central chondral defects, and it may actually increase the load in patients with medial defects.

Adult↗
PubMed2005

Effect of simulated shoulder thermal capsulorrhaphy using radiofrequency energy on glenohumeral fluid temperature.

PURPOSE: To determine joint fluid temperatures at different time intervals during treatment with radiofrequency energy (RFE) applied in intermittent and continuous treatment manners under flow or no-flow conditions using a simulated shoulder joint model. TYPE OF STUDY: In vitro measurement of simulated joint fluid temperature during RFE treatment. METHODS: A custom-built jig with a chamber (volume size, 25 mL) was used to mimic the adult human shoulder. Three RFE systems: Vulcan EAS plus TAC-S probe (Smith & Nephew Endoscopy, Andover, MA); VAPR II plus End-Effect Electrode (Mitek, Westwood, MA); and ArthroCare 2000 plus TurboVac 90 degrees probe (ArthroCare, Sunnyvale, CA) were tested in the chamber with saline solution initially set at 23 degrees C. Each RFE probe was applied in a paintbrush pattern on the capsular tissue in the chamber and a fluoroptic thermometry probe was placed 1 cm above the RFE treatment probe to record the fluid temperature. Both intermittent and the continuous treatment manners were tested under flow and no-flow conditions. For each probe/manner/flow combination, 6 bovine capsular tissue specimens were tested (n = 6). All data were recorded using a HyperTerminal software program (Hilgraeve Inc, Monroe, MI) into a personal computer. RESULTS: When using intermittent and continuous treatment manners with flow, all recorded chamber fluid temperatures for all tested RFE probes at each time interval were below 40 degrees C. Under no-flow conditions, with intermittent treatment, the ArthroCare probe caused joint fluid temperatures to exceed 50 degrees C after 70 seconds of RFE treatment. With the continuous treatment, the ArthroCare caused chamber fluid temperatures to exceed 65 degrees C after 2 minutes of treatment. The highest mean recorded chamber fluid temperature was caused by ArthroCare probe, which reached 80 degrees C at 3 minutes. For all probes, continuous treatment caused significantly higher chamber fluid temperatures than intermittent treatment. CONCLUSIONS: The results of this study indicate that using flow during thermal capsulorrhaphy could lower joint fluid temperature to prevent heated joint fluid from killing chondrocytes of articular cartilage, and the intermittent treatment manner caused lower fluid temperature compared with continuous treatment within the RFE-treated shoulder joint. CLINICAL RELEVANCE: Articular cartilage of the humeral head may suffer potential thermal injury from heating of joint fluid during RFE thermal capsulorrhaphy.

Animals↗
PubMed2005

Rapid progression of chondral disease in the lateral compartment of the knee following meniscectomy.

We present 2 cases of severe, rapidly progressive chondral disease in the lateral compartment within 12 months after meniscectomy. In both cases, the lateral compartment was salvaged with simultaneously performed cartilage repair techniques and meniscal transplantation. The first case is of a 16-year-old boy who suffered a complex irreparable posterior horn lateral meniscus tear that was treated with an aggressive partial meniscectomy, and developed a rapid onset of severe lateral compartment symptoms associated with a focal grade IV chondral defect of the lateral femoral condyle within 10 months of his index meniscectomy. The second case is that of an athletic 43-year-old orthopaedic surgeon who suffered a complex lateral meniscus tear that required a near total lateral meniscectomy. Within 5 months of the lateral meniscectomy, he developed severe lateral symptoms with a focal grade IV chondral defect of the lateral femoral condyle. In both cases, the articular cartilage defects were treated with osteochondral grafting at the time of lateral meniscus transplantation with excellent results at 2-year follow-up. These cases highlight the significant need for a heightened the awareness of the relatively increased risk of rapid lateral compartment degeneration following lateral meniscectomy. This, in combination with the appropriate use of cartilage restoration techniques, provides the potential to salvage or prevent rapid onset, unicompartmental degenerative disease, and the ability to reduce symptoms and improve function in these challenging patients.

Adolescent↗
PubMed2005

Nonarthroplasty treatment of glenohumeral cartilage lesions.

Treatment of young, active persons with symptomatic cartilage lesions of the glenohumeral joint represents a significant challenge. Diagnosis of glenohumeral chondral defects is not always straightforward and effective treatment requires familiarity with a number of techniques. Low-demand individuals may accept palliative therapy in the form of arthroscopic debridement as a temporizing solution. However, younger, high-demand individuals require a careful, stepwise approach that includes reparative, restorative, and reconstructive strategies. Reparative strategies use marrow-stimulation techniques to induce formation of fibrocartilage. Restorative tactics attempt to replace damaged cartilage with hyaline or hyaline-like tissue using osteochondral or chondrocyte transplantation. Large lesions that are not candidates for reparative or restorative procedures can be approached using reconstruction methods such as biologic resurfacing. This review examines causes of chondral injury in the glenohumeral joint, discusses diagnostic strategies, and presents a practical framework including palliative, reparative, restorative, and reconstructive options with which one can formulate a treatment plan for these patients.

Adrenal Cortex Hormones↗