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PubMed2002

Shoulder instability: accuracy of MR imaging performed after surgery in depicting recurrent injury--initial findings.

PURPOSE: To analyze a series of postoperative magnetic resonance (MR) images obtained in patients with recurrent signs or symptoms of instability in whom subsequent surgical correlation was performed to determine the accuracy in diagnosing recurrent injury. MATERIALS AND METHODS: The authors identified 24 patients who underwent MR imaging after shoulder instability surgery and had recurrent instability requiring repeat surgery. Twelve nonenhanced MR images and six indirect and six direct MR arthrograms were retrospectively reviewed with consensus to determine the presence or absence of recurrent labral or rotator cuff tear. Operative reports were reviewed to confirm the presence or absence of labral or rotator cuff tear. The mean interval between initial surgery and MR imaging was 10 months. The mean interval until repeat surgery was 2 months. RESULTS: Overall, the accuracy of postoperative MR imaging was 79% in depicting recurrent labral tear and 88% in depicting recurrent rotator cuff tear. Indirect MR arthrography had 100% accuracy for recurrent labral tear detection, whereas direct MR arthrography and nonenhanced MR imaging had accuracies of 67% and 75%, respectively. Direct MR arthrography was more sensitive, 100% versus 71%, but less specific, 60% versus 80%, than nonenhanced MR imaging in depicting recurrent labral tears. Direct MR arthrography had 100% accuracy in depicting rotator cuff tear, whereas both indirect MR arthrography and nonenhanced MR imaging had 83% accuracy. CONCLUSION: MR imaging, indirect MR arthrography in particular, appears to be an accurate means of evaluating the shoulder following instability surgery.

Adult↗
PubMed1988

Shoulder instability: evaluation with MR imaging.

Instability of the glenohumeral joint is a common cause of chronic shoulder pain and disability. One or more episodes of subluxation or dislocation may result in a tear, detachment, or attenuation of the glenoid labrum, stripping of the joint capsule from the scapula, or trauma to the tendons or muscles of the rotator cuff. A series of 27 shoulders examined with magnetic resonance (MR) imaging showed changes of glenohumeral instability, which were confirmed with open or arthroscopic surgery. MR imaging was capable of displaying common types of pathologic conditions resulting from instability, including labral trauma, capsular detachment, and retraction of the subscapularis muscle. MR imaging is a valuable diagnostic tool for the evaluation of glenohumeral instability.

Humans↗
PubMed1988

Normal instability of the hip in the neonate: US standards.

In recent years, the use of real-time ultrasonography (US) has enabled dynamic evaluation of the infant hip through a range of motion and stress. Preliminary experience has suggested that a certain amount of instability in the hips of newborns is normal, but no standards have been established. In this study, a group of term neonates whose physical examinations were normal were examined with US on the 1st and 2d days of life. Each hip was imaged in the transverse plane in nonstressed and stressed positions, and movement of the femoral head under stress was quantitated. This displacement under stress was used to establish a normal range of hip instability in neonates. Patterns of hip laxity in boys and girls are identical, and in most infants hip instability diminishes between the 1st and 2d days of life. Our method of quantitating hip instability produces consistent results, with intraobserver 95% confidence intervals of +/- 1.2 mm for each measurement.

Birth Weight↗
PubMed1995

Anterior shoulder instability: diagnostic criteria determined from prospective analysis of 121 MR arthrograms.

PURPOSE: To determine magnetic resonance (MR) arthrographic criteria in the diagnosis of anterior glenohumeral instability. MATERIALS AND METHODS: In 121 patients with diagnoses proved surgically, the labrum, glenohumeral ligaments, and capsular insertion types were assessed prospectively with gadolinium-enhanced MR arthrography. Findings were compared in stable and unstable shoulders. RESULTS: Operative results showed 59 normal, 57 torn, and five deficient labra. In 37 unstable shoulders, 31 had discrete inferior labral-ligamentous lesions and six had capsular laxity. MR arthrograms showed labral abnormalities with 92% sensitivity, 92% specificity. Inferior labral-ligamentous lesions enabled prediction of anterior instability with 76% sensitivity (capsular laxity was missed in all shoulders), 98% specificity. Inferior labral-ligamentous abnormalities were strongly associated with unstable shoulders (P << .0001), whereas noninferior labral-ligamentous abnormalities were related to stable shoulders (P = .01). Capsular insertion types showed no significant differences between stable and unstable shoulders (P > .8). CONCLUSION: On MR arthrograms, inferior labral-ligamentous abnormalities were most closely correlated with anterior glenohumeral instability. Capsular insertion sites had no role in the prediction of shoulder instability.

Adolescent↗
PubMed2005

[Association between microsatellite instability and clinico-pathological characteristics in sporadic colon cancer].

BACKGROUND AND OBJECTIVE: Currently, colon cancer is a leading cause of cancer death world-wide. It progresses according to three molecular pathways, named suppressor, mutador and methylator. Microsatellite instability is a hallmark of the lack of reparation, of DNA mismatches and it characterizes a subset of colon tumors (unstable tumors, MSI). MSI-H patients (high degree of microsatellite instability) seem to share clinico-pathological differences with MSS (microsatellite stable) and MSI-L (low degree of microsatellite instability) patients. In this study, associations between high degree of microsatellite instability and pathological (location, mucinous content, differentiation grade, stages T3N0, stages II and III) and clinical features (response to chemotherapy, disease-free survival and overall survival) were evaluated. PATIENTS AND METHOD: 117 patients with sporadic colon cancer were classified into two populations (MSS/MSI-L and MSI-H) by using PCR and electrophoresis of seven microsatellites, according to the National Cancer Institute recommendations. RESULTS: MSI-H tumors tended to be located in the right colon (p = 0.022) and were of mucinous histologic type (p = 0.04). No differences in disease-free survival and overall survival between group of stage II and III patients with MSS/ MSI-L and corresponding ones with MSI-H colon cancer were found (p = 0.54, p = 0.37, respectively). Conversely, MSI-H patients with stage II colon cancer had a favourable prognosis (p = 0.027). Nevertheless, response to 5-fluorouracil (5-FU) and leucovorin was similar in MSS/ MSI-L and MSI-H groups (p = 0.38). CONCLUSIONS: MSI-H patients are characterized by certain pathological features; those MSI-H patients with a stage II seem to have a better prognosis than MSS/ MSI-L patients.

Colonic Neoplasms↗
PubMed2004

Kaposi's sarcoma-associated herpesvirus induction of chromosome instability in primary human endothelial cells.

Chromosome instability contributes to the multistep oncogenesis of cancer cells. Kaposi's sarcoma (KS), an angiogenic vascular spindle cancer of endothelial cells, displays stage advancement with lesions at early stage being hyperproliferative, whereas lesions at late stage are clonal or multiclonal and can exhibit a neoplastic nature and chromosome instability. Although infection with KS-associated herpesvirus (KSHV) has been associated with the initiation and promotion of KS, the mechanism of KS neoplastic transformation remains unclear. We show that KSHV infection of primary human umbilical vein endothelial cells induces abnormal mitotic spindles and centrosome duplication. As a result, KSHV-infected cells manifest chromosome instability, including chromosomal misalignments and laggings, mitotic bridges, and formation of micronuclei and multinucleation. Our results indicate that KSHV infection could predispose cells to malignant transformation through induction of genomic instability and contributes to the development of KS.

Cell Transformation, Viral↗
PubMed2005

Genetic disruption of cytosine DNA methyltransferase enzymes induces chromosomal instability in human cancer cells.

DNA methyltransferase 1 (DNMT1)-deficient mice are tumor-prone, and this has been proposed to result from the induction of genomic instability. To address whether loss of DNMT1, or the related protein DNMT3b, results in genomic instability in human cancer cells, we used a near-diploid human colorectal cancer cell line, HCT116, in which one or both DNMT genes were disrupted by homologous recombination. Array-based comparative genomic hybridization analyses indicated that double, but not single, DNMT knock-out cells display two specific alterations in regional DNA copy number, suggesting that DNMT deficiency and genomic DNA hypomethylation are not associated with widespread genomic amplifications or deletions in human cancer cells. However, spectral karyotype analyses revealed that DNMT-deficient HCT116 cells are highly unstable with respect to large-scale chromosomal alterations; furthermore, this effect is characterized by a high degree of individual cell heterogeneity. The induction of chromosomal alterations in DNMT-deficient cells was evidenced both by aneuploidy and by large increases in the number of novel chromosomal translocations. Studies of double knock-out cells indicated that the generation of chromosomal alterations is spontaneous and persistent in vitro, meeting the formal definition of genomic instability. In summary, we show that DNMT deficiency in human cancer cells results in constitutive genomic instability manifested by chromosomal translocations.

Aneuploidy↗
PubMed2006

Loss of DNA polymerase zeta causes chromosomal instability in mammalian cells.

Rev3L encodes the catalytic subunit of DNA polymerase zeta (pol zeta) in mammalian cells. In yeast, pol zeta helps cells bypass sites of DNA damage that can block replication enzymes. Targeted disruption of the mouse Rev3L gene causes lethality midway through embryonic gestation, and Rev3L-/- mouse embryonic fibroblasts (MEFs) remain in a quiescent state in culture. This suggests that pol zeta may be necessary for tolerance of endogenous DNA damage during normal cell growth. We report the generation of mitotically active Rev3L-/- MEFs on a p53-/- genetic background. Rev3L null MEFs exhibited striking chromosomal instability, with a large increase in translocation frequency. Many complex genetic aberrations were found only in Rev3L null cells. Rev3L null cells had increased chromosome numbers, most commonly near pentaploid, and double minute chromosomes were frequently found. This chromosomal instability associated with loss of a DNA polymerase activity in mammalian cells is similar to the instability associated with loss of homologous recombination capacity. Rev3L null MEFs were also moderately sensitive to mitomycin C, methyl methanesulfonate, and UV and gamma-radiation, indicating that mammalian pol zeta helps cells tolerate diverse types of DNA damage. The increased occurrence of chromosomal translocations in Rev3L-/- MEFs suggests that loss of Rev3L expression could contribute to genome instability during neoplastic transformation and progression.

Animals↗
PubMed2005

The relationship between global methylation level, loss of heterozygosity, and microsatellite instability in sporadic colorectal cancer.

PURPOSE: The relationship between global hypomethylation, chromosomal instability (CIN), and microsatellite instability (MSI) remains unclear in colorectal cancer. The aim of this study was to investigate the relationship between global methylation status, loss of heterozygosity (LOH), and MSI in sporadic colorectal cancer. EXPERIMENTAL DESIGN: We determined global methylation levels in 80 sporadic colorectal cancers, 51 adjacent normal tissues, and 20 normal tissues using the long interspersed nucleotide elements-combined bisulfite restriction analysis method. We also analyzed 80 colorectal cancers for MSI status and LOH at chromosomes 5q21, 8p12-22, 17p13, and 18q21. RESULTS: We identified 14 cases of MSI (17.5%) and 58 cases of LOH (72.5%). LOH was observed more frequently in microsatellite stable (MSS) cancers than in MSI cancers at all loci. Colorectal cancers showed significantly lower global methylation levels than did normal tissues (41.0+/-9.7% versus 54.3+/-6.5%; P<0.001). MSS cancers showed significantly lower global methylation levels when compared with MSI cancers (39.5+/-9.4% versus 48.2+/-8.2%; P=0.003). Tumors with global hypomethylation (with <or=40% of methylation levels) had a significantly increased number of chromosomal loci with LOH than did tumors without global hypomethylation (1.9 versus 0.9; P<0.001); 11 tumors (13.9%) lacked both MSI and LOH. This subgroup had significantly higher global methylation levels (46.8+/-8.7%) than did MSS cancers with LOH (38.0+/-9.0%; P=0.006). CONCLUSIONS: These data showed a significant association between global hypomethylation and chromosomal instability in sporadic colorectal cancer. This suggests that global hypomethylation plays an important role in inducing genomic instability in colorectal carcinogenesis.

Adult↗
PubMed2004

Possible causes of chromosome instability: comparison of chromosomal abnormalities in cancer cell lines with mutations in BRCA1, BRCA2, CHK2 and BUB1.

A large proportion of epithelial cancers show the chromosome-instability phenotype, in which they have many chromosome abnormalities. This is thought to be the result of mutations that disrupt chromosome maintenance, but the causative mutations are not known. We identified cell lines known to have mutations that might cause chromosome instability, and examined their karyotypes. Two cell lines, the breast cancer line HCC1937 and the pancreatic cancer line CAPAN-1, that have mutations respectively in BRCA1 and BRCA2, had very abnormal karyotypes, with many structural and numerical chromosome changes and substantial variation between metaphases. However, two colorectal cancer lines with mutations in BUB1, a spindle checkpoint protein involved in chromosome segregation, had rather simple near-tetraploid karyotypes, with minimal loss or gain of chromosomes other than the endoreduplication event, and minimal structural change. Apart from tetraploidy, these karyotypes were typical of colorectal lines considered to be chromosomally stable. Two lines derived from the same tumour, DLD-1 and HCT-15, with bi-allelic mutation of CHK2, had karyotypes that were typical of near-diploid colorectal lines considered chromosomally stable. The karyotypes observed supported the proposed role for BRCA1 and BRCA2 mutations in chromosomal instability, but showed that the tested mutations in BUB1 and CHK2 did not result in karyotypes that would have been predicted if they were sufficient for chromosomal instability.

Adenocarcinoma↗
PubMedDate not supplied

Prospective evaluation of thermal capsulorrhaphy for shoulder instability: indications and results, two- to five-year follow-up.

BACKGROUND: Thermal shrinkage of capsular tissue has recently been proposed as a means to address the capsular redundancy associated with shoulder instability. Although this procedure has become very popular, minimal peer-reviewed literature is available to justify its widespread use. PURPOSE: To prospectively evaluate the efficacy of arthroscopic electrothermal capsulorrhaphy for the treatment of shoulder instability. STUDY DESIGN: This nonrandomized prospective study evaluated the indications and results of thermal capsulorrhaphy in 84 shoulders with an average follow-up of 38 months. METHODS: Patients were divided into three clinical subgroups: traumatic anterior dislocation (acute or recurrent), recurrent anterior anterior/inferior subluxation without prior dislocation, and multidirectional instability. Patients underwent arthroscopic thermal capsulorrhaphy after initial assessment, radiographs, and failure of a minimum of 3 months of nonoperative rehabilitation. RESULTS: Outcome measures included pain, recurrent instability, return to work/sports, and the American Shoulder and Elbow Surgeons (ASES) Shoulder Assessment score. Overall results were excellent in 33 participants (39%), satisfactory in 20 (24%), and unsatisfactory in 31 (37%). CONCLUSIONS: The high rate of unsatisfactory overall results (37%), documented with longer follow-up, is of great concern. The authors conclude that enthusiasm for thermal capsulorrhaphy should be tempered until further studies document its efficacy.

Adolescent↗
PubMed1983

Comparison of static and dynamic repairs for ligamentous instability of the knee.

Twenty-three patients who have had a MacIntosh type of fasciodesis for anterolateral rotary instability of the knee have been studied. Overall 73% were improved by this procedure; of those whose only instability was when turning on the run, 90% improved. These results have been compared with a series of 51 patients who had a pes anserinus transfer for anteromedial instability (D'Arcy 1978). It is suggested that both static and dynamic reconstructions have a place in the management of knee instability resulting from anterior cruciate injury.

Adolescent↗
PubMed1984

Lateral and anterior instability in acute ankle distortion. A radiologic investigation.

In a prospective consecutive investigation radiologic tests for lateral and anterior instability in acute ankle distortion were found to be reliable indications of lateral ligament ruptures. Arthrography of the ankle joint was used as reference. Absence of instability, however, gives little information as to the ligamental status. The size of this group constitutes a clinical problem. Better results are achieved by combining lateral and anterior instability tests. If only one test is used, the anterior instability test should be preferred. The results of the two tests bare no relation to the degree of ligament ruptures found at operation.

Adolescent↗
PubMedDate not supplied

Osteitis pubis and instability of the pubic symphysis. When nonoperative measures fail.

Seven rugby players with osteitis pubis and vertical instability at the pubic symphysis were treated operatively after nonoperative treatment had failed to improve their symptoms. The vertical instability was diagnosed based on flamingo view radiographs showing greater than 2 mm of vertical displacement. The players had undergone at least 13 months of nonoperative therapy before surgery was considered. Operative treatment consisted of arthrodesis of the pubic symphysis by bone grafting supplemented by a compression plate. At a mean follow-up of 52.4 months, all patients were free of symptoms and flamingo views confirmed successful arthrodesis with no residual instability of the pubic symphysis. Based on our results with this procedure, we believe that arthrodesis of the pubic symphysis has a role in the treatment of osteitis pubis that is recalcitrant to nonoperative treatment. The combination of osteitis pubis and vertical pubis symphyseal instability may be the cause of failure of nonoperative treatment.

Adult↗
PubMedDate not supplied

Arthroscopic management of glenohumeral instability.

There has been substantial development of techniques for performing arthroscopic surgery of the shoulder over the past 20 years. A multitude of arthroscopic techniques have been developed in an attempt to manage the unstable glenohumeral joint while decreasing surgical morbidity. The results obtained with arthroscopic stabilization have been widely variable. This review will examine the current status of arthroscopic management of glenohumeral instability. The techniques and results of arthroscopic stabilization for primary anterior glenohumeral instability, recurrent anterior instability, and multidirectional instability will be discussed. A brief discussion on thermal capsulorrhaphy is included.

Arthroscopy↗
PubMedDate not supplied

Recurrent shoulder instability after open reconstruction in athletes involved in collision and contact sports.

The purpose of this study was to evaluate the incidence of recurrent instability in a group of young athletes who underwent open shoulder stabilization with a modified Bankart repair and anterior capsulorrhaphy. Recurrent dislocation was defined as an instability episode resulting in complete dislocation requiring manual reduction. Recurrent subluxation was defined as the subjective history of the shoulder "slipping or popping out" or pain and apprehension that caused cessation of athletics for at least 1 day. Sixty-six patients (64 men and 2 women) were included in the study. A collision sport precipitated instability in 53 patients and a contact sport in 13. The average follow-up was 47 months (range, 24 to 72). The average American Shoulder and Elbow Surgeons score was 95 points (range, 71 to 100). The average Rowe score was 80 points (range, 40 to 100). Two patients had experienced recurrent dislocation after surgery (3%). Eight patients (12%) had rare (fewer than three) episodes of postsurgical subluxation. Five patients (8%) had multiple recurrent subluxations after surgery. Postsurgical recurrent instability was significantly associated with preoperative episodes of subluxation. However, all patients with rare subluxation had an excellent functional result.

Adult↗
PubMedDate not supplied

Arthroscopic repair for traumatic posterior shoulder instability.

BACKGROUND: The role of arthroscopic repair in the treatment of posterior shoulder instability remains poorly defined. PURPOSE: To evaluate the results of arthroscopic repair of posterior Bankart lesions. STUDY DESIGN: Retrospective review. METHODS: Records were reviewed of 27 shoulders (26 patients). All of the patients were male with a mean age of 28.7 years; in all cases symptoms were preceded by a traumatic event. Fourteen of the patients had 2+ to 3+ posterior translation noted under preoperative anesthesia. The posterior capsulolabral complex was found to be detached from the glenoid rim in all cases; bioabsorbable tack fixation was used for repair. RESULTS: At a mean follow-up of 5.1 years, no patients demonstrated a range of motion deficit. Muscle weakness (grade 4/5) in external rotation was noted in two patients (8%). There was no instability greater than 1+ in the anterior, posterior, or inferior directions. The mean L'Insalata shoulder score was 90.0 +/- 13.9. The mean SF-36 physical and mental component scores were 50.4 +/- 7 and 53.9 +/- 9, respectively. Symptoms of pain and instability were eliminated in 24 patients (92%). Two patients (8%) required additional surgery after arthroscopic repair of the posterior Bankart lesion. Radiographs demonstrated that there had been no progressive glenohumeral joint degeneration. CONCLUSIONS: Arthroscopic repair of the posterior capsulolabral complex is an effective means of eliminating symptoms of pain and instability associated with posterior Bankart lesions of traumatic origin.

Absorbable Implants↗
PubMed2004

Glenohumeral arthrosis in anterior instability before and after surgical treatment: incidence and contributing factors.

BACKGROUND: Few large series of arthropathy related to anterior glenohumeral instability are available in the orthopaedic literature, preventing analysis of the incidence and the risk factors of preoperative and postoperative glenohumeral arthritis. HYPOTHESIS: Anterior stabilization surgery influences the risk factors of glenohumeral arthritis. STUDY DESIGN: Retrospective review. METHODS: There were 570 patients who underwent an instability procedure. Clinical and radiographic preoperative data were collected for these patients. Arthritis was evaluated preoperatively and postoperatively with the Samilson classification. The mean age at surgery was 31.9 years. Follow-up averaged 6.5 years. RESULTS: The preoperative incidence of arthritis was 9.2%. Arthritic risk factors were older age at the initial dislocation and at surgery, increased length of time from the initial dislocation until surgery, and the presence of osseous glenoid rim lesions. Postoperative arthritis in patients without any preoperative arthritis occurred in 19.7% and was correlated with older age at the initial dislocation and at surgery, increased number of dislocations, and longer follow-up. Decreased external rotation at latest follow-up correlated with arthritis, although whether this was the cause or the effect was unclear. CONCLUSIONS: Similar factors contribute to preoperative and postoperative arthritis in patients with anterior glenohumeral instability, suggesting that surgery does not influence the risk factors of arthritis. Although decreased external rotation with the arm at side statistically correlated with arthritis in this study, the authors were unable to establish this as an effectual relationship because nearly all patients with glenohumeral osteoarthritis, whether instability related or not, have decreased external rotation.

Adult↗