PubMed Health⌕ Search

Biomedical subjects

John C Richmond

Publications and source records attributed to John C Richmond.

At least 19 recordsLinked to original sources
PubMed2006

Responsiveness of the International Knee Documentation Committee Subjective Knee Form.

BACKGROUND AND PURPOSE: The International Knee Documentation Committee Subjective Knee Form was developed to measure change in symptoms, function, and sports activity in patients treated for a variety of knee conditions. Although previous research has demonstrated reliability and validity of the form, its responsiveness has not been evaluated. The purpose of this study was to determine responsiveness of the International Knee Documentation Committee Subjective Knee Form. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 1. METHODS: Patients who participated in the original validation study for the International Knee Documentation Committee Subjective Knee Form completed the form and a 7-level global rating of change scale that ranged from greatly worse to greatly better after a mean of 1.6 years (range, 0.5-2.3 years). Analyses included calculation of the standardized response mean and mean change in International Knee Documentation Committee Subjective Knee Form score compared to the patient's perception of change on the global rating of change scale. In addition, a receiver operating characteristic curve was plotted to determine the change in score that best distinguished patients who improved from those who did not. RESULTS: The overall standardized response mean was 0.94, which is considered large. With the exception of those who were slightly worse or unchanged, the mean change in the International Knee Documentation Committee Subjective Knee Form score compared to the patients' perceived global ratings of change was as expected (greatly worse, -15.1; somewhat worse, -8.4; slightly worse, 20.6; no change, 10.7; slightly better, 5.9; somewhat better, 18.1; greatly better, 38.7). The receiver operating characteristic curve analysis revealed that a change score of 11.5 points had the highest sensitivity, and a change score of 20.5 points had the highest specificity to distinguish between those who were or were not improved. CONCLUSION: The International Knee Documentation Committee Subjective Knee Form is a responsive measure of symptoms, function, and sports activity for patients with a variety of knee conditions.

Adolescent↗
PubMed2006

Transhumeral head plasty for large Hill-Sachs lesions.

Large, engaging Hill-Sachs lesions can cause recurrent glenohumeral instability following Bankart repair of torn anterior capsulolabral structures. We offer a novel technique for correcting the posterolateral humeral head defect without significantly altering normal anatomic structures. The glenohumeral joint is exposed via a deltopectoral approach. After the defect geometry is appreciated by direct palpation and visualization, the tip of an anterior cruciate ligament tibial guide is centered in the defect. The drill sleeve is approximated to the anterior lesser tuberosity starting hole, and a graduated guidewire is advanced to the posterior subchondral surface. After confirmation of satisfactory positioning, an 8-mm cannulated acorn drill is drilled to within 1 cm of the posterior surface. Bone tamps are used to elevate the depressed area using the tunnel created within the head. Allograft cancellous bone chips are impacted into the defect to elevate and support the subchondral surface. After successful impaction grafting and restoration of the head surface, anterior capsulolabral reconstruction is undertaken using either the Bankart or Latarjet technique. A standard Bankart rehabilitation program is followed postoperatively. We confirmed the clinical efficacy of our technique in 4 patients who experienced no instability or other complications at an average of 1-year follow-up.

Humans↗
PubMed2005

Arthroscopic findings in the knee in nail-patella syndrome: a case report.

Nail-patella syndrome is a rare genetic disorder that can cause significant morbidity in several organs, including the musculoskeletal system. This case report describes our arthroscopic findings in the knees of an adolescent with bilateral hypoplastic and subluxed patellae. Our findings suggest that early intervention should be considered whenever this syndrome is recognized. This may modify some of the long-term joint problems seen in adults with nail-patella syndrome.

Abnormalities, Multiple↗
PubMed2005

Reconstruction of the anterior cruciate ligament: meta-analysis of patellar tendon versus hamstring tendon autograft.

PURPOSE: No graft tissue has consistently shown superiority over others for reconstruction of the anterior cruciate ligament (ACL). Bone-patellar tendon-bone (BPTB) and doubled hamstring tendon (semitendinosus and gracilis) (HT) are the most commonly used autologous grafts. We performed a meta-analysis to compare the effectiveness of ACL reconstruction using either BPTB or HT grafts. TYPE OF STUDY: Systematic review and meta-analysis. METHODS: We searched the MEDLINE database (1966 to April 2003) for English-language randomized or prospective studies comparing BPTB and 3- or 4-strand HT grafts used for ACL reconstruction. For inclusion, studies were required to follow identical rehabilitation protocols within each study, and provide subjective or objective outcome data after a minimum average 2-year follow-up. Comparison data between BPTB and HT for each identified outcome measure were combined using a random-effects model meta-analysis. RESULTS: Eleven reports fulfilled the criteria for inclusion. Outcomes favoring BPTB were found in the following outcome measures: normal Lachman examination (relative risk [RR], 0.91; 95% confidence interval [CI], 0.83-0.99; P = .025), normal pivot-shift (RR, 0.94; 95% CI, 0.88-1.0; P = .067), KT-1000 manual-maximum side-to-side difference of < or = 3 mm (RR, 0.75; 95% CI, 0.55-1.01; P = .057), and fewer reconstructions resulting in flexion loss > 5 degrees (RR, 1.41; 95% CI, 1.01-1.96; P = .04). Intermediate level laxity was more common with the HT graft, as shown by higher rates of abnormal Lachman > 0 (RR, 1.22; 95% CI, 0.99-1.5; P = .06), pivot-shift > 0 (RR, 1.3; 95% CI, 0.96-1.75; P = .09), and KT-1000 manual-maximum side-to-side differences > 3 mm (RR, 1.64; 95% CI, 1.13-2.39; P = .01). Outcome measures that favored HT were absence of patellofemoral crepitance (RR, 1.08; 95% CI, 1.01-1.15; P = .03), fewer results with extension loss > 5 degrees (RR, 0.56; 95% CI, 0.3-1.03; P = .06), and kneeling pain. The incidence of instability, as defined by Lachman grade 2, pivot-shift grade 2, or KT-1000 manual-maximum side-to-side difference > 5 mm, was not significantly different between the 2 grafts. All other outcome measures were not significantly different. CONCLUSIONS: The data presented in this meta-analysis show that the incidence of instability is not significantly different between the BPTB and HT grafts. However, BPTB was more likely to result in reconstructions with normal Lachman, normal pivot-shift, KT-1000 manual-maximum side-to-side difference < 3 mm, and fewer results with significant flexion loss. In contrast, HT grafts had a reduced incidence of patellofemoral crepitance, kneeling pain, and extension loss. The choice of graft by the patient and surgeon must be individualized, and the results of this meta-analysis can aid in the decision by clarifying the risks and benefits of each surgical approach. LEVEL OF EVIDENCE: Level I.

Anterior Cruciate Ligament↗
PubMed2005

Growth factor induced fibroblast differentiation from human bone marrow stromal cells in vitro.

Utilizing a two-dimensional tissue culture plastic screening system and a fractional factorial design, specific media formulations and growth factor combinations were determined that support human bone marrow stromal cell (BMSC) differentiation toward fibroblast characteristics for utilization in tissue engineering, specifically cell morphology and alignment, metabolic activity, abundant expression of collagen types I and III, and negligible expression of other tissue-specific markers. BMSCs were cultured for up to 14 days on tissue culture plastic, supplemented with Dulbecco's Minimal Essential Medium (DMEM)/10% FBS or Advanced DMEM(ADMEM)/5% FBS. Each medium base was supplemented with one of nine possible growth factor combinations and ascorbate-2-phosphate (Asc-2-P) for the duration of culture. ADMEM supported comparable cell viability with half the serum content of the DMEM formulation. Asc-2-P was potent in promoting BMSC proliferation, in the absence of a mitogen, supporting significant increases in cell activity over 14 days of culture. DMEM promoted significant increases in cell viability for 7 of 9 growth factor groups when compared to their ADMEM counterparts. ADMEM, however, promoted increased cell transcript and protein expression, as 5 of 9 growth factor combinations induced a 200% increase in collagen type I versus equivalent DMEM cultures. Cell morphology and collagen type I immunostaining, when assessed in context of MTT and RNA results, identified 3 growth factor and medium combinations that supported fibroblast differentiation for future development of ligament tissue in vitro.

Bone Marrow Cells↗
PubMed2005

Characterization of transcript levels for matrix molecules and proteases in ruptured human anterior cruciate ligaments.

An improved understanding of cellular responses during normal anterior cruciate ligament (ACL) function or repair is essential for clinical assessments, understanding ligament biology, and the implementation of tissue engineering strategies. The present study utilized quantitative real-time RT-PCR combined with univariate and multivariate statistical analyses to establish a quantitative database of marker transcript expression that can provide a "blueprint" of ACL wound healing. Selected markers (collagen types I and III, biglycan, decorin, MMP-1, MMP-2, MMP-9, and TIMP-1) were assessed from 33 torn ACLs harvested during reconstructive surgery. Trends were observed between postinjury period and marker expressions. Significant correlations between marker expression existed and were most prominent between collagen types I and III. Canonical correlation analysis established a relationship between patient demographics and a combination of all marker expressions. The currently observed trends and correlations may assist in identifying appropriate tissue samples and provide a baseline information of marker expression level that can support in vitro optimization of environmental cues for ligament tissue engineering application.

Adolescent↗
PubMed2004

Osteonecrosis after arthroscopic meniscectomy using radiofrequency.

The purpose of this report is to describe a case of osteonecrosis that occurred after arthroscopic meniscectomy associated with a radiofrequency device. The patient developed increasing knee pain and disability 6 months after arthroscopic meniscectomy. Magnetic resonance imaging showed subchondral osteonecrosis of both femoral condyles with cyst formation.

Arthroscopy↗
PubMed2004

Matrix metalloproteinases and their clinical applications in orthopaedics.

Imbalance in the expression of matrix metalloproteinases and their inhibitors contribute considerably to abnormal connective tissue degradation prevalent in various orthopaedic joint diseases such as rheumatoid arthritis and osteoarthritis. Matrix metalloproteinase expression has been detected in ligament, tendon, and cartilage tissues in the joint. They are known to contribute to the development, remodeling, and maintenance of healthy tissue through their ability to cleave a wide range of extracellular matrix substrates. Their role has been extended to cell growth, migration, differentiation, and apoptosis. In orthopaedics, their clinical applications constantly are being explored. The multiple steps in matrix metalloproteinase regulation offer potential targets for inhibition, useful in drug therapy. The correlation between matrix metalloproteinases and progression in joint erosion presents potential prognostic and diagnostic tools in rheumatoid arthritis. Matrix metalloproteinases also can be incorporated into scaffold design to control the degradation rate of engineered tissue constructs. This current review aims to summarize and emphasize the importance of matrix metalloproteinases and their natural inhibitors in the maturation of musculoskeletal tissue through matrix remodeling and, therefore, in the generation of a new clinical potential in orthopaedics.

Humans↗
PubMed2003

Expert panel on anterior cruciate ligament case studies.

Anterior cruciate ligament (ACL) reconstructions cannot, and should not, be considered "recipe-driven" or "cookie-cutter" operations. There are multiple variables that must be considered both pre- and intraoperatively in order to execute a successful procedure. The following case studies present a number of challenging situations, many of which do not have a straightforward, or only one, solution. The goal is to provide some ral-life clinical situations in which the reader can "observe" an expert panel of ACL surgeons working through the problems--offering solutions based on science, experience, and intuition.

Adult↗
PubMed2003

Arthroscopic capsular shrinkage of the shoulder for the treatment of patients with multidirectional instability: Minimum 2-year follow-up.

PURPOSE: The study goal was to evaluate the arthroscopic treatment of patients with multidirectional instability of the shoulder (MDI). MDI is a disabling condition as a result of pain and restriction of activity. The treatment of MDI is primarily nonsurgical (supervised physiotherapy). TYPE OF STUDY: Prospective cohort study. METHODS: Arthroscopic capsular shrinkage, using a bipolar radiofrequency system, was performed in 32 patients (33 shoulders). The mean age was 27 years (range, 15 to 49). The Constant score was used for assessment preoperatively and at 6-month intervals. In 8 patients, labral lesions were revealed at arthroscopy and were addressed using arthroscopic methods. RESULTS: The follow-up was from 24 to 33 months (26 mean). Patients without labral pathology (group A) and patients with labral lesions (group B) are discussed separately. Group A showed an increase in the mean Constant score at 6 months, but the scores reached a plateau after 6 months. Statistical analysis using 1-way analysis of variance (ANOVA) showed that the mean difference between the preoperative Constant score and the score at latest follow-up was statistically significant (P <.0001; 95% confidence interval, 13.4 to 31.6; standard error, 2.2). The rate of failure or complication was 16%. Three patients experienced recurrence of instability and another developed adhesive capsulitis. Overall, patient satisfaction was 83%. Group B showed an improvement in the Constant scores, and all 8 patients were satisfied. No clinical recurrence of the instability was seen in this group. However, 1 patient developed adhesive capsulitis. This group is too small to draw any statistically valid conclusions. CONCLUSIONS: The early results are encouraging. Postoperative physiotherapy is of paramount importance. Continued long-term follow-up of this relatively new technique is required to determine the failure rate increase that is likely to occur at longer time intervals.

Activities of Daily Living↗
PubMed2002

Future direction of the treatment of ACL ruptures.

The future of treatment of the ACL rupture is changing as our understanding of the biology surrounding the ACL continues to increase. It is our expectation that clinically applicable treatments, including the repair of the ACL and the development of a biologically engineered ACL, will occur in the next decade.

Animals↗
PubMed2002

Silk matrix for tissue engineered anterior cruciate ligaments.

A silk-fiber matrix was studied as a suitable material for tissue engineering anterior cruciate ligaments (ACL). The matrix was successfully designed to match the complex and demanding mechanical requirements of a native human ACL, including adequate fatigue performance. This protein matrix supported the attachment, expansion and differentiation of adult human progenitor bone marrow stromal cells based on scanning electron microscopy, DNA quantitation and the expression of collagen types I and III and tenascin-C markers. The results support the conclusion that properly prepared silkworm fiber matrices, aside from providing unique benefits in terms of mechanical properties as well as biocompatibility and slow degradability, can provide suitable biomaterial matrices for the support of adult stem cell differentiation toward ligament lineages. These results point toward this matrix as a new option for ACL repair to overcome current limitations with synthetic and other degradable materials.

Animals↗
PubMed2002

[15O]water pharmacokinetics: influence of age and gender in normal subjects.

PURPOSE: To compile a normal database for the characterization of global [15O]water pharmacokinetic behavior. PROCEDURES: The influences of age, gender, and body habitus on the pharmacokinetics of [15O]water were investigated in a series of normal subjects, N = 100 (50 males, 50 females, age = 19-79) who were participants in cognitive activation studies. Arterial blood was analyzed by autosampler and parametric images were constructed using a 40-second summed image and the autoradiographic model. RESULTS: Males and females were comparable with respect to age, number of injections administered, and dose (mCi) administered per injection but differed significantly with respect to height, weight, and normalized dose (mCi/kg). There were significant gender-based differences in the bolus arrival time, global cerebral blood flow (gCBF), area-under-the-curve (AUC), summed image concentration, and dose-normalized concentration but not dose-normalized AUC. Bolus arrival time, gCBF and dose-normalized AUC were significantly influenced by age. CONCLUSION: Age and gender are significant determinants of [15O]water pharmacokinetic behavior.

Journal Article↗
PubMed2002

Contamination levels in blood samples drawn from the injection intravenous line.

PURPOSE: Securing two intravenous lines, one for injection and one for blood sampling, can be nearly impossible in compromised patients, therefore, a need exists to quantify the potential error when simplified techniques are employed. METHOD: Two venous catheters were placed. 2-deoxy-2-[18F]fluoro-glucose (FDG) was infused through one of the catheters. Venous blood samples were drawn from each line. Triplicate aliquots of plasma were analyzed in duplicate. RESULTS: Concentrations from the infusion line were 2.0% higher than the concentrations from the noninfusion line. The average error was 3.3%, 2.0%, and 0.7% higher for the first, second, and third samples, respectively. CONCLUSIONS: Blood sampling through the infusion catheter is a viable alternative to the placement of separate venous catheters. Sampling from the injection catheter, even with tubing flush and replacement, will potentially incur small (generally < 10%) over-estimations in concentration in initial samples. Subsequent sampling reduces the error to essentially zero by the third sample.

Journal Article↗
PubMed2002

Advanced bioreactor with controlled application of multi-dimensional strain for tissue engineering.

Advanced bioreactors are essential for meeting the complex requirements of in vitro engineering functional skeletal tissues. To address this need, we have developed a computer controlled bench-top bioreactor system with capability to apply complex concurrent mechanical strains to three-dimensional matrices independently housed in 24 reactor vessels, in conjunction with enhanced environmental and fluidic control. We demonstrate the potential of this new system to address needs in tissue engineering, specifically toward the development of a tissue engineered anterior cruciate ligament from human bone-marrow stromal cells (hBMSC), where complex mechanical and biochemical environment control is essential to tissue function. Well-controlled mechanical strains (resolution of < 0.1 micron for translational and < 0.1 degree for rotational strain) and dissolved oxygen tension (between 0%-95% +/- 1%) could be applied to the developing tissue, while maintaining temperature at 37 +/- 0.2 degrees C about developing tissue over prolonged periods of operation. A total of 48 reactor vessels containing cell culture medium and silk fiber matrices were run for up to 21 days under 90 degrees rotational and 2 mm translational deformations at 0.0167 Hz with only one succumbing to contamination due to a leak at an medium outlet port. Twenty-four silk fiber matrices seeded with human bone marrow stromal cells (hBMSCs) housed within reactor vessels were maintained at constant temperature (37 +/- 0.2 degrees C), pH (7.4 +/- 0.02), and pO2 (20 +/- 0.5%) over 14 days in culture. The system supported cell spreading and growth on the silk fiber matrices based on SEM characterization, as well as the differentiation of the cells into ligament-like cells and tissue (Altman et al., 2001).

Biomimetics↗
PubMed2001

Cell differentiation by mechanical stress.

Growth factors, hormones, and other regulatory molecules are traditionally required in tissue engineering studies to direct the differentiation of progenitor cells along specific lineages. We demonstrate that mechanical stimulation in vitro, without ligament-selective exogenous growth and differentiation factors, induces the differentiation of mesenchymal progenitor cells from the bone marrow into a ligament cell lineage in preference to alternative paths (i.e., bone or cartilage cell lineages). A bioreactor was designed to permit the controlled application of ligament-like multidimensional mechanical strains (translational and rotational strain) to the undifferentiated cells embedded in a collagen gel. The application of mechanical stress over a period of 21 days up-regulated ligament fibroblast markers, including collagen types I and III and tenascin-C, fostered statistically significant cell alignment and density and resulted in the formation of oriented collagen fibers, all features characteristic of ligament cells. At the same time, no up-regulation of bone or cartilage-specific cell markers was observed.

Animals↗