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PubMed2006

Contralateral force sense deficits are related to the presence of functional ankle instability.

Residual symptoms that often follow lateral ankle sprains can lead to functional ankle instability. Proprioceptive deficits have been identified as one factor that may contribute to the presence of functional ankle instability. Sixty participants were recruited to participate in the study. Seven questions were used to determine the presence of functional ankle instability in each participant. A point was added for each "yes" response to produce an index that represents an interval data scale of functional ankle instability. Contralateral force sense and active joint reposition sense were measured in all participants. Pearson product moment correlations were calculated to determine the relationship between functional ankle instability and force sense and active joint reposition sense. We found a significant relationship with force sense and functional ankle instability. Specifically, force sense variable error at both test forces (10 and 30% of maximal voluntary isometric contraction) were positively correlated to the presence of functional ankle instability, r=0.26; p<or=0.05 and r=0.25; p<or=0.05, respectively. All other force sense correlations were not statistically significant. No significant correlations were identified between active joint reposition sense and functional ankle instability. This study indicates that participants with functional ankle instability have deficits in low load force sense, but not active joint reposition sense.

Adolescent↗
PubMed2006

Genetic instability in human tumors.

Genetic, or genomic, instability refers to a series of observed spontaneous genetic changes occurring at an accelerated rate in cell populations derived from the same ancestral precursor. This is far from a new finding, but is one that has increasingly gained more attention in the last decade due to its plausible role(s) in tumorigenesis. The majority of genetic alterations contributing to the malignant transformation are seen in growth regulatory genes, and in genes involved in cell cycle progression and arrest. Genomic instability may present itself through alterations in the length of short repeat stretches of coding and non-coding DNA, resulting in microsatellite instability. Tumors with such profiles are referred to as exhibiting a mutator phenotype, which is largely a consequence of inactivating mutations in DNA damage repair genes. Genomic instability may also, and most commonly, results from gross chromosomal changes, such as translocations or amplifications, which lead to chromosomal instability. Telomere length and telomerase activity, important in maintaining chromosomal structure and in regulating a normal cell's lifespan, have been shown to have a function in both suppressing and facilitating malignant transformation. In addition to such direct sequence and structural changes, gene silencing through the hypermethylation of promoter regions, or increased gene expression through the hypomethylation of such regions, together, form an alternative, epigenetic mechanism leading to instability. Emerging evidence also suggests that dietary and environmental agents can further modulate the contribution of genetic instability to tumorigenesis. Currently, there is still much debate over the distinct classes of genomic instability and their specific roles in the initiation of tumor formation, as well as in the progressive transition to a cancerous state. This review examines the various molecular mechanisms that result in this genomic instability and the potential contribution of the latter to human carcinogenesis.

Cell Transformation, Neoplastic↗
PubMed1997

[Dynamic pedography for assessing functional ankle joint instability].

Chronic functional instability of the lateral ankle may be difficult to distinguish from mechanical instability when radiological stress test reveal only small ligamentous defects. When a decision for or against surgical reconstruction of the ligaments has to be made it can be helpful to use additional information on joint function. Therefore, a prospective study of 65 patients (mean age 24.1 +/- 4.6 years) with long-standing chronic ankle instability was conducted to demonstrate that the dynamic measurement of plantar pressure distribution can identify patients with functional ankle instability. Plantar pressure patterns were measured during gait by means of a capacitive platform, the EMED-SF system. The impulses at eight points of the foot were calculated intraindividually and compared with those in a group of 100 healthy subjects. On the basis of clinical criteria alone, the two groups of patients were distinguished, 35 with functional instability and 30 with mechanical instability. The patients with functional instability showed significantly increased lateral loading of the unstable foot (P = 0.01), whereas the group with mechanical instability tended to walk more on the medial side of the unstable foot. This finding is explained by a deficit or peroneal strength during the stance phase, based on a proprioceptive deficit after trauma. The new technique provides additional information, which is relevant and sufficiently important to help in making decisions about the individual patient with chronic instability.

Adult↗
PubMed2003

[SLAP lesions as a cause of posterior instability].

SLAP lesions disrupt the perilabral architecture, but so far there have been no reports about posterior instability due to SLAP lesions. In a prospective study of 30 patients with recurrent posterior instability, we found SLAP lesions as a reason for instability in three cases. The purpose of this study is to point out that SLAP lesions can be a cause of posterior instability. Thirty patients with clinical posterior shoulder instability underwent diagnostic arthroscopy before operative stabilization procedures, three of whom (three males, aged 29-51 years) showed a SLAP lesion (once case each of types II, III, and IV) as a cause of posterior instability. All three patients had a history of a fall on the outstretched arm. All patients underwent arthroscopic refixation of the labrum. After arthroscopic refixation of the SLAP lesions, two patients were completely stable (SLAP II and III), whereas one patient (SLAP IV) reported microinstability during overhead activity but complete stability during activity of daily living. The same patient complained about moderate pain in extreme external-flexion rotation with slightly reduced range of motion in external-flexion position. All other patients were free of pain and showed free range of motion. Our results demonstrate that SLAP lesions can be a cause for posterior shoulder instability. In our cases, posterior shoulder instability caused by SLAP lesions was successfully treated by arthroscopic refixation of the torn biceps anchor. When treating posterior shoulder instability, SLAP lesions should be taken into account.

Adult↗
PubMed2006

Genomic instability in invasive breast carcinoma measured by inter-Simple Sequence Repeat PCR.

We have measured genomic instability in invasive breast carcinomas and assessed the relationship of genomic instability to known tumor prognostic factors. DNAs from tumors and adjacent normal tissue of 18 breast cancer patients were subjected to inter-Simple Sequence Repeat (inter-SSR) PCR for quantitation of tumor genomic instability. Associations between genomic instability level and known breast cancer prognostic factors were evaluated using the Pearson Product Moment Correlation, the Kruskal-Wallis test of independent samples and the Mann-Whitney non-parametric test. Genomic instability was detected by inter-SSR PCR in over 90% of the breast tumors. The mean instability index was 3.08% (0-7.59%), approximately the same mean value observed in studies of colorectal and thyroid carcinomas. Significantly higher levels of instability were associated with tumors exhibiting necrosis. Genomic instability as measured is detected in the majority of breast cancers at levels comparable to other tumor types. Hypoxia, such as that observed in necrotic regions of tumors, has been associated with elevated genomic damage. We hypothesize that the higher levels of genomic instability detected in necrotic tumors is a consequence of hypoxia-associated DNA damage.

Adult↗
PubMed2004

Cis-acting transmission of genomic instability.

Genomic instability is a highly pleiotropic phenotype, which may reflect a variety of underlying mechanisms. Destabilization has been shown in some cases to involve mutational alteration or inactivation of trans-acting cellular factors, for example, p53 or mismatch repair functions. However, aspects of instability are not well explained by mutational inactivation of trans-acting factors, and other epigenetic and cis-acting mechanisms have recently been proposed. The trans and cis models result in divergent predictions for the distribution of instability-associated genetic alterations within the genome, and for the inheritance of genomic instability among sibling sub-clones of unstable parents. These predictions have been tested in this study primarily by tracking the karyotypic distribution of chromosomal rearrangements in clones and sub-clones exhibiting radiation-induced genomic instability; inheritance of mutator phenotypes was also analyzed. The results indicate that genomic instability is unevenly transmitted to sibling sub-clones, that chromosomal rearrangements within unstable clones are non-randomly distributed throughout the karyotype, and that the majority of chromosomal rearrangements associated with instability affect trisomic chromosomal segments. Observations of instability in trisomic regions suggests that in addition to promoting further alterations in chromosomal number, aneuploidy can affect the recovery of structural rearrangements. In summary, these findings cannot be fully explained by invoking a homogeneously distributed factor acting in trans, but do provide support for previous suggestions that genomic instability may in part be driven by a cis-acting mechanism.

Aneuploidy↗
PubMed2002

Gait adaptations in patients with chronic posterior instability of the knee.

OBJECTIVE: A retrospective analysis was performed to assess gait in individuals with a long history of posterior knee instability. DESIGN: Descriptive study. BACKGROUND: There are few studies in the literature concerning evaluation of the biomechanics of the knee in patients with knee posterior instability. METHODS: Nine individuals with posterior knee instability and a matched control group of uninjured subjects were tested in regards to knee kinematics and kinetics while walking and ascending and descending stairs. The mean follow up time for the individuals with posterior instability was 11.1 years. Individual satisfaction with the knee was measured by having participants complete the Flandry (also known as Hughston Clinic) self-assessment questionnaire. RESULTS: It was found that patients with knee posterior instability who indicated a higher level of satisfaction on the Flandry score walked in a manner that demonstrated greater peak knee extensor torque during stance phase, while less satisfied patients with knee posterior instability demonstrated lower peak knee extensor torque. There was a significant correlation between the self-assessment score and the peak knee extensor torque during level walking (P=0.003). During stair ascent and descent, patients with posterior instability averaged lower knee extensor torque and power than the control subjects, but those differences were only statistically significant in power while descending stairs (P=0.048). CONCLUSIONS: Individuals with chronic knee posterior instability modify their gait, and the adaptation can be predicted based upon the individuals self-assessment of their knee using the Flandry questionnaire. RELEVANCE: These data suggest that gait retraining may be a valuable addition to the traditional muscle strengthening programs, which are commonly used during conservative management of knee posterior instability.

Adaptation, Physiological↗
PubMed2003

Electrothermal capsulorrhaphy in glenohumeral instability without Bankart tear.

PURPOSE: The purpose of this study is to review the clinical results of electrothermal capsulorrhaphy (ETC) performed on 23 patients for the treatment of glenohumeral instability at an minimum follow-up of 2 years. TYPE OF STUDY: Retrospective case series. METHODS: Twenty-six patients with symptomatic unidirectional or multidirectional glenohumeral instability without Bankart tear were treated with ETC using a radiofrequency probe. No labral repairs were performed. A standard postoperative rehabilitation protocol was followed. Patients were evaluated with respect to motion, direction of instability, need for repeat surgery, return to overhand sports, and symptoms of pain and instability using various scores. RESULTS: Twenty-three patients were available for follow-up evaluation at an average of 30 months. The overall average ASES and Rowe scores were 84.2 and 79.3, respectively. Recurrent instability requiring an open stabilization procedure occurred in 4 patients (17%), 2 with anterior and 2 with multidirectional instability. Seven of 14 overhead athletes (50%) reported inability to return to their previous level. According to Rowe scores, overall results were 11 excellent, 5 good, 4 fair, and 3 poor. No postoperative nerve complications occurred. CONCLUSIONS: The ETC procedure was safely performed to treat glenohumeral instability without Bankart lesions. The recurrence rate is similar to that for other arthroscopic procedures but higher than for open surgery. In the absence of Bankart tear, patients with multidirectional instability and overhand athletes may require something other than an isolated ETC procedure to address instability. Long-term results of ETC are needed to better define its surgical indications.

Adolescent↗
PubMed1989

Glenohumeral instability.

Glenohumeral instability is an important cause of shoulder pain and disability in an active population. An awareness of the prevalence of recurrent instability, either in the form of dislocation or subluxation, is particularly useful in the assessment of the young athlete presenting with shoulder pain. Young adults presenting with rotator cuff tendinitis may have an underlying instability as the primary cause of their problem. A careful clinical examination should determine whether the instability is voluntary or involuntary, of traumatic or atraumatic onset, and the primary direction of the instability, as these factors have important implications with regard to treatment. Anterior glenohumeral instability is most common and the incidence of recurrent instability following on from an initial dislocation is high in the young active patient. An intensive rehabilitation programme is indicated for all initial dislocations or subluxations but surgery may become necessary after failure of conservative treatment. Care must be taken to determine accurately those patients with voluntary or multi-directional instability and a longer trial of conservative treatment is indicated here, as results of operative treatment in those cases are less favourable. Conservative treatment should be directed at strengthening the dynamic stabilizers of the shoulder joint, notably the rotator cuff muscles. Additional X-ray views are needed to demonstrate all the radiological changes associated with recurrent instability and further evaluation with examination under anaesthesia and arthroscopy is beneficial in the assessment of these patients. Arthroscopic surgery also has a role in the treatment of patients with symptomatic labral pathology and is now being used to perform stabilization procedures in selected cases. Many operative procedures have been described for stabilization of the shoulder and these should be directed at correcting the pathology present. Restoration of the patient's flexibility and strength postoperatively is essential, especially in the athlete in order to allow a full return to sporting activity.

Combined Modality Therapy↗
PubMed2004

Microsatellite instability and expression of hMLH1 and hMSH2 proteins in ovarian endometrioid cancer.

Microsatellite instability and loss of heterozygosity has been implicated in ovarian carcinogenesis. The reported frequency of microsatellite instability in human ovarian cancer varies significantly owing to the use of heterogeneous tumor histotypes and various microsatellite markers in different laboratories. In this study, we determined the frequency of microsatellite instability in 74 ovarian endometrioid carcinomas using four microsatellite markers (BAT25, BAT26, D5S346, D17S250), and examined hMLH1 and hMSH2 protein expression. In all, 20% of the tumors were microsatellite instability high (two or more markers showing instability) and 12% were microsatellite instability low (one marker showed instability). Loss of hMLH1 and/or hMSH2 expression was found in nine of 15 microsatellite instability-high tumors. The microsatellite instability-high phenotype tended to occur more frequently in low-grade tumors (P=0.053), but did not correlate with clinical stage. Totally, 38% of cases also displayed loss of heterozygosity at D17S250; this loss of heterozygosity was associated with high clinical stage (P=0.097). Our results indicate that both microsatellite and loss of heterozygosity at D17S250 are involved in the development of ovarian endometrioid carcinoma.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Radiation-induced DNA damage and delayed induced genomic instability.

Ionizing radiation induces genomic instability, which is transmitted over many generations after irradiation through the progeny of surviving cells. Induced genomic instability is manifested as the expression of the following delayed effects: delayed reproductive death or lethal mutation, chromosomal instability, and mutagenesis. Since induced genomic instability accumulates gene mutations (actually genomic instability is the process whereby gene mutation increases subtle difference) and gross chromosomal rearrangements, it has been thought to play a role in radiation-induced carcinogenesis. Radiation-induced genomic instability exerts its effects for prolonged periods of time, suggesting the presence of a mechanism by which the initial DNA damage in the surviving cells is memorized. Recent studies have shown that such memory transmission causes delayed DNA breakage, which in turn plays a role in the induction of delayed phenotypes. Although radiation-induced genomic instability has been studied for years, many questions remain to be answered. This review summarizes the current data on radiation-induced genomic instability. In particular, the mechanism(s) involved in the initiation and perpetuation of radiation-induced genomic instability, and a role of delayed activation of p53 protein are discussed.

Animals↗
PubMedDate not supplied

Laser capsulorrhaphy for multidirectional instability of the shoulder. An outcomes study and proposed classification system.

BACKGROUND: Clinical data on the efficacy of laser capsulorrhaphy for the treatment of multidirectional instability of the shoulder are limited. HYPOTHESIS: The diagnosis of multidirectional instability includes a spectrum of pathologic symptoms that warrants subclassification; laser capsulorrhaphy alone is not uniformly effective for all subtypes. STUDY DESIGN: Retrospective review of prospectively collected data. METHODS: Twenty-five shoulders in 21 patients were treated with laser capsulorrhaphy for multidirectional instability. Functional outcomes at a mean duration of 32 months' follow-up (range, 24 to 48 months) were recorded. RESULTS: Instability recurred in 60% of patients with congenital multidirectional instability, 17% of patients with acquired multidirectional instability, and 33% of patients with posttraumatic multidirectional instability (overall recurrence rate, 40%). Generalized ligamentous laxity was a risk factor for recurrence. Patient satisfaction rates were 40%, 83%, and 22% for the congenital, acquired, and posttraumatic subgroups. Reasons for dissatisfaction included recurrent instability, persistent pain, and inability to return to athletic activity at desired capacity. The overall mean postoperative Simple Shoulder Test score was 84%. The mean postoperative numeric rating score for pain was 3.3 (10-point scale). CONCLUSIONS: Laser capsulorrhaphy may be effective for patients with acquired multidirectional instability secondary to repetitive microtrauma but is less predictable in the other subgroups.

Adolescent↗
PubMed2006

The modified Bristow procedure for anterior shoulder instability: 26-year outcomes in Naval Academy midshipmen.

BACKGROUND: Many procedures have been proposed for the correction of anterior shoulder instability. Some of these procedures address the problem anatomically, such as the Bankart procedure, and some prevent instability nonanatomically, such as the Bristow-Latarjet procedure. A modified Bristow procedure was the procedure of choice for anterior shoulder instability among midshipmen at the United States Naval Academy from 1975 to 1979. HYPOTHESIS: The modified Bristow procedure for anterior shoulder instability provides good shoulder function and stability in the long term. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: There were 52 shoulders in 49 patients reviewed at a mean follow-up of 26.4 years. The Rowe score, Single Assessment Numeric Evaluation, and Western Ontario Shoulder Instability Index were used to assess outcomes. RESULTS: The mean Rowe score was 81.8 (range, 5-100), and the mean Single Assessment Numeric Evaluation score was 82.9 (range, 30-100), with an overall Single Assessment Numeric Evaluation of 71.2% (37 of 52 shoulders) rated as good and excellent. The mean Western Ontario Shoulder Instability Index was 376 of 2100 (range, 0-1560). Overall, recurrent instability occurred in 8 of 52 shoulders (15.4%), with recurrent dislocation in 5 shoulders (9.6%) and recurrent subluxation in 3 shoulders (5.8%). The mean time to recurrent dislocation was 7.0 years. CONCLUSION: This study represents the longest follow-up in the literature of the modified Bristow procedure. The authors have shown nearly 70% good and excellent results and recurrent instability comparable with other long-term follow-up studies of open instability procedures.

Adolescent↗
PubMed1996

Carpal instability in the weight-bearing upper extremity.

The prevalence of carpal instability in a paraplegic population was investigated to establish an association between chronic repetitive stress on the wrist and the development of such instability. Nine of 162 paraplegic patients had static carpal instability and no history of an acute injury of the wrist. The predominant pattern of instability, found in eleven wrists (six patients), was non-dissociative volar intercalated segmental instability. The prevalence of carpal instability increased with the duration of weight-bearing on the upper extremity. Eighteen per cent of the patients in whom the spinal cord injury had occurred more than twenty years before the study had carpal instability. Carpal instability in these weight-bearing upper extremities and the increase in its prevalence with the duration of the forces across the wrist demonstrate an association between chronic repetitive stress on the wrist and carpal instability.

Adult↗
PubMed2005

Posterolateral rotatory instability of the elbow following radial head resection.

BACKGROUND: Resection is a common procedure for the treatment of comminuted fractures of the radial head. While radial head resection is associated with a high success rate when performed for appropriate indications, a number of well-defined biomechanical complications have been reported following this procedure, including proximal migration of the radius, the development of valgus deformity, and recurrent elbow instability in the acute setting. However, posterolateral rotatory instability has not previously been recognized as a complication of radial head resection. While the absence of the radial head makes the diagnosis difficult, we have identified a series of patients with posterolateral rotatory instability following radial head resection. We believe that this instability is secondary to unrecognized lateral ulnar collateral ligament deficiency. METHODS: Between November 1995 and September 2000, forty-two patients were evaluated because of elbow or forearm complaints following radial head resection. Seven patients (17%) were diagnosed with posterolateral rotatory instability on the basis of characteristic clinical and radiographic findings. RESULTS: The study group included five men and two women with a mean age of forty-two years. All seven patients had had radial head excision for the treatment of a comminuted radial head fracture at a mean of forty-four months (range, four months to sixteen years) prior to referral. All seven patients had lateral elbow pain, a sense of instability and/or weakness, and a positive lateral pivot-shift test. Posterolateral rotatory instability secondary to lateral ulnar collateral ligament insufficiency was confirmed intraoperatively in the four patients who were managed surgically. CONCLUSIONS: Clinicians should be aware that posterolateral rotatory instability may be a cause of unexplained elbow pain and instability following radial head resection. This diagnosis has implications for the prevention and treatment of this condition.

Adult↗
PubMed1999

Usefulness of Posner's definition of spinal instability for selection of surgical treatment for lumbar spinal stenosis.

The aim of this study was to determine the usefulness of Posner's definition of spinal instability for selection of surgical therapy for lumbar spinal stenosis. Sixty patients with lumbar spinal stenosis were studied. Thirty-three patients were found to have instability, as defined using Posner's method. Nineteen of the 33 patients with instability underwent decompression and instrumented fusion. The 14 remaining patients with instability underwent decompression alone. Twenty-seven patients without instability were treated by decompression alone. Patients treated by decompression and fusion obtained the best results. Good results also could be obtained by decompression alone only if patients did not have instability. However, patients treated by decompression alone in the presence of instability had the worst results. The Posner's definition of instability proved useful for selecting patients with instability for fusion treatment.

Adult↗
PubMed2002

[Evaluation of carpal instability after distal radius fracture].

In this study carpal stability was assessed in a group of patients with distal fractures of the radius. The aim of this study was to: assess the frequency of carpal instability as a concomitant lesion to fractures of the distal radius, determine the type of instability and its correlation to fracture type and patient age, assess the influence of bone fragment dislocation on the type of instability. For a clinical evaluation of carpal instability results of physical examination and X-ray examination performed in both static and dynamic conditions were taken into account. In 33% of the examined cases different types of instability were noted. Carpal instability was found more often among younger patients, predominantly of the dorsal type. The type of observed instability depended mainly on the injury mechanism and fracture type of the distal radial epiphysis. Fracture type did not influence the frequency of carpal instability, whereas direction and degree of bone fragment displacement did correlate to the type of primary or secondary instability.

Adult↗
PubMed1994

[Dynamic anterior jerk of the shoulder. A new clinical test for shoulder instability. Preliminary study].

PURPOSE OF STUDY: A new clinical test named "The shoulder anterior jerk test" is proposed to confirm the diagnosis of chronic shoulder anterior instability. MATERIAL: The test combines of a compression force and a translation force, applied along the arm between the humeral head and the glenoid cavity. In so doing, a subluxation of the humeral head is provoked and it is accompanied with a jerk recognised by the patient as his instability. METHODS: Three different populations of patients had been studied: Population A: 28 patients operated on for chronic anterior dislocation, uni or bilateral (32 shoulders), had been tested before the operation, without and under anesthesia. Population B: 100 patients without any problem at the shoulder, had been tested before and under anesthesia done for knee or hip surgery. Population C: 100 young sportive athletes with normal shoulder tested without anesthesia. RESULTS: Population A: The 28 patients suffering from shoulder instability had all a positive shoulder jerk test under anesthesia. Without anesthesia the test had been positive only in 10 cases (30 per cent). The jerk is potentially present for all the patients, but it is disturbed by apprehension. Population B: Among the 200 shoulders tested, 26 shoulders (17 patients) had a positive test under anesthesia (13 per cent). 5 had positive jerk test without anesthesia. Population C: 5 among the 200 shoulders tested had a positive jerk test (2.5 per cent) Under anesthesia the test has a sensitivity of 100 per cent, a specificity of 87 per cent, a positive predictive value of 55 per cent and a negative value of 100 per cent. Without anesthesia, the test has a sensitivity of 31 per cent, a specificity of 97.5 per cent, a positive predictive value of 66 per cent and a negative predictive value of 90 per cent. DISCUSSION: The instability which is shown by the jerk test is in relation with the anterior subluxation of the humeral head in front of the anterior edge of the glenoïd cavity. It reproducts, with a minimal amplitude, the clinical instability which is recognized by the patient. The test is always positive under anesthesia in case of chronic anterior instability, it may confirm pre-operative diagnosis just before the begining of the procedure and may orientate the choice of it. Apprehension is a major obstacle to the research of the jerk, but it is the same with the other classical clinical tests of the shoulder anterior instability. CONCLUSION: The anterior jerk test of the shoulder is thus a test which is able to prove the diagnosis of an anterior instability. The future will permit to confirm its efficiency and will confirm if the test may differenciate anterior and inferior instability with variation of the abduction, as it has been shown in this preliminary study.

Adolescent↗