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PubMed1995

Peroneus longus and tibialis anterior muscle activity in the stance phase. A quantified electromyographic study of 10 controls and 25 patients with chronic ankle instability.

The electromyographic activity of the peroneus longus and anterior tibial muscles of 25 patients with chronic ankle instability (18 patients with bilateral symptoms and 7 patients with unilateral complaints) and 10 controls was registered during the stance phase under different walking conditions. With balance secured by external support, there was a variable amount of peroneal activity, most of which was found in the third quarter of stance. A high increase in peroneus longus activity starting after foot-flat was found when subjects had to maintain balance in a natural way. No difference in peroneal activity was found in relation to instability complaints. It is thought that the peroneus longus serves to maintain balance, that this function decreases with increase of speed and that one cannot rely on this muscle to prevent an inversion injury during normal walking. The anterior tibial muscle was predominantly active in the first quarter after heel contact. An increase in activity in the second quarter as an effect of loss of secured balance suggests that this muscle plays some part in balance control, but this is not its main function. A significant increase in tibialis anterior activity was found in patients with bilateral instability. No significant difference was found between the symptomatic and asymptomatic leg of patients with unilateral instability under the same walking conditions. These findings suggest changes in central control.

Adult↗
PubMed2005

Symptomatic atlantoaxial instability in Down syndrome.

OBJECT: The aim of this study was to audit the treatment of symptomatic atlantoaxial instability in Down syndrome and to assess factors associated with fusion failure in this group of patients. METHODS: The authors reviewed the cases of 12 children with Down syndrome presenting with symptomatic atlantoaxial instability who underwent surgery for internal fixation and fusion. A review of clinical histories, radiological investigations, and details of operative interventions was also performed. The mode of presentation was acute spinal cord injury (five cases), progressive myelopathy (four cases), and neck pain or stiffness (three cases). The atlantodental interval ranged from 5 to 13 mm. The posterior atlantodental interval at the C-1 level was 9.5 mm (range 6-11 mm). In 10 patients an os odontoideum was present. Translocation of the odontoid process occurred in one patient, and occipitoatlantal instability was also identified in two cases. Twenty-four operations were performed in the 12 patients. A transoral odontoidectomy was required in four children. Successful fusion was demonstrated in seven patients at the first operation. Three of the five patients with acute cord injury made significant functional recovery and were left with no or mild disability. CONCLUSIONS: Additional bone abnormalities at the CVJ are common in the Down syndrome population. Young age at the time of fusion and multiple osseous anomalies pose a higher risk factor in fusion failure. The authors recommend an aggressive surgical approach for management of symptomatic cases of CVJ instability.

Adolescent↗
PubMed2002

Atlantoaxial instability in Dyggve-Melchior-Clausen syndrome. Case report and review of the literature.

Dyggve-Melchior-Clausen (DMC) syndrome is a very rare disease. Only 58 cases have been reported in the literature. The syndrome is probably an autosomal recessive inherited disorder, one that is characterized by mental retardation, the short-spine type of dwarfism, and skeletal abnormalities, especially of the spine, hands, and pelvis. Atlantoaxial instability-induced spinal cord compression is a serious and preventable complication. The purpose of this report is to describe the first case of DMC syndrome in which anterior transarticular atlantoaxial screw fixation was used to treat atlantoaxial instability. The authors report on a 17-year-old man with DMC syndrome and concomitant severe atlantoaxial instability. Computerized tomography scanning and magnetic resonance angiography demonstrated an irregular course of the vertebral artery (VA) at C-2, which made a posterior fixation procedure impossible. Additionally, transoral fusion was impossible because the patient was unable to open his mouth sufficiently. Therefore, the patient underwent anterior transarticular screw fixation. Follow-up examination 36 weeks after surgery showed solid fusion without implant failure. In conclusion, treatment of atlantoaxial instability in DMC syndrome must be considered. Specific care must be taken to determine the course of the VA. If posterior and transoral fusion are impossible, anterior transarticular atlantoaxial screw fixation might be the only alternative.

Adolescent↗
PubMed2006

CIN By WNT: growth pathways, mitotic control and chromosomal instability in cancer.

There is mounting evidence suggesting that an instable genome is directly involved in the development of cancer. The predominant form of genomic instability in most cancers presents itself as an increased rate of loss or gain in chromosome number and parts, referred to as chromosomal instability (CIN). Indeed, mutations in components of mitotic checkpoints have been described in human cancers, albeit in low numbers, suggesting that although CIN principally arises due to defective surveillance of mitosis, its molecular causes remain largely unclear. We have recently shown that the Wnt/beta-catenin signaling pathway, whose aberrant activation has been established as the driving force of tumorigenesis in many cancers particularly colorectal cancer, can generate CIN through the transcriptional target gene conductin/axin2. Here we propose a model for the generation of CIN by aberrant Wnt/beta-catenin signaling and we suggest that growth pathways not only control cell cycle progression through G(1)/S transition but have also evolved cross talks to regulate mitosis. We speculate that aberrant activation of these pathways, as observed in cancer can result in chromosomal instability thus explaining the widespread appearance of CIN in human cancers.

Animals↗
PubMedDate not supplied

Diagnosis of shoulder instability in dogs and cats: a retrospective study.

The glenohumeral joint is a remarkable articulation providing the greatest range of motion of any joint in the body. Glenohumeral stability results from several mechanisms, including those that do not require expenditure of energy by muscle ("passive mechanisms") and those that do ("active mechanisms"). Glenohumeral instability has been recognized in 47 shoulders of 45 dogs and one cat. Cases are presented because of chronic foreleg lameness. Shoulder joint pain is obviated by the orthopedic examination. Only 57% of the involved shoulders presented with degenerative joint disease. Signs of instability are recognized under anesthesia using a craniocaudal or mediolateral drawer sign or both. This report describes the radiographic and arthroscopic findings of shoulder instability. Arthroscopy of the shoulder joint allows identification of all intra-articular pathologies. Shoulder instability, not fully recognized in the past, appears to be the most common cause of shoulder lameness in the dog.

Animals↗
PubMed2006

Nontraumatic upper cervical spine instability in children.

The upper cervical spine begins at the base of the occiput, continues caudally to the C2-C3 disk space, and includes the occipitoatlantal and atlantoaxial joints. Nontraumatic upper cervical spine instability can result from abnormal development of osseous or ligamentous structures or from gradually increasing ligamentous laxity associated with connective tissue disorders. Such instability can lead to compression of the spinal cord during movement of the cervical spine. Establishing a correct diagnosis includes performing a thorough physical examination as well as evaluating radiographic relationships and measurements. Appropriate management of syndromes associated with instability of the upper cervical spine includes preventive care and recommendations for sports participation. Surgical treatment for the upper cervical spine includes a posterior surgical approach, used for instability, and the use of rigid plate implants, wiring, and bone graft materials to achieve a solid spinal fusion.

Age Factors↗
PubMed1994

Sonographic evaluation of posterior instability and dislocation of the shoulder: prospective study.

Owing to the exceptional mechanical precariousness of the glenohumeral joint, dislocations and instabilities are common. Because posterior dislocation or instability of the joint occurs infrequently, these abnormalities may be misdiagnosed on routine radiographic examinations in acute shoulder injuries. We present five patients in whom sonographic examination was used to diagnose posterior shoulder instability (three cases) and posterior shoulder dislocation (two cases). The sonographic technique demonstrates the presence of instability or dislocation and permits dynamic examination of the shoulder joint. Ultrasonography emerges as a useful and efficient novel technique for detecting these disorders. The accuracy, sensitivity, and specificity of the technique presented here are currently being determined.

Adult↗
PubMed1999

Shoulder instability in young athletes.

The term "shoulder instability" constitutes a spectrum of disorders that includes dislocation, subluxation and laxity. Anterior instability is the most common form of glenohumeral instability and may be associated with nerve injury. The diagnosis of anterior, posterior or multidirectional instability is based on a thorough history and physical examination that includes specific provocative maneuvers. The load-and-shift test, the relocation test, the drawer test, the sulcus test and the anterior apprehension test are useful for assessment of the shoulder. Radiographic studies should include special views to delineate specific lesions, such as a Bankart lesion and a Hill-Sachs defect. Early surgical intervention may be a consideration, especially in younger patients. Recent studies suggest that surgical intervention after the first dislocation may reduce the rate of recurrence. Rehabilitation is accomplished in four phases, beginning with rest and pain control and proceeding to isometric and isotonic exercises. The goal is for the patient to reach 90 percent strength in the injured shoulder compared with the uninjured shoulder.

Athletic Injuries↗
PubMed1999

Blatt dorsal capsulodesis for scapholunate instability.

This retrospective series reviews 17 patients with scapholunate instability treated with the Blatt procedure between 1994 and 1997. Indications were 11 cases of preradiographic instability, three dynamic and three static instabilities. Subjective and objective assessment was carried out. Average pain and level of activity score was 60.8/80 (good). Only three patients failed to continue their jobs. Ten patients were fully satisfied, and seven had minor to major reservations. Flexion loss averaged 11 degrees and extension loss was 11.3 degrees. Grip force improved significantly by 11.2 kg. Associated scapholunate interosseous ligament repair in 6 patients resulted in no further improvement. Major complications were deep infection (one case) and reflex sympathetic dystrophy (two cases). Given the lack of a superior procedure, we considered the Blatt capsulodesis a valuable therapeutic option for cases of preradiographic and dynamic instability, or as an adjunct to scapholunate interosseous ligament repair in more acute lesions.

Adolescent↗
PubMed2000

Posterolateral dislocation of the elbow joint. Relationship to medial instability.

BACKGROUND: Dislocation of the elbow joint is the second most common dislocation in the upper extremity, dislocation of the shoulder being the most common. It has been reported that uncomplicated dislocation of the elbow joint may be associated with a decreased range of motion, degenerative changes in the elbow joint, ectopic calcification, or neurological deficits. As the medial collateral ligament complex can be completely disrupted during dislocation, we evaluated the association between the long-term results of treatment of simple posterolateral dislocation of the elbow and the presence of persistent medial or valgus elbow instability. METHODS: Fifty patients who had a mean age of thirty-three years (range, eighteen to fifty-eight years) had closed reduction of a posterolateral dislocation of the elbow without associated fractures. The extremity was immobilized in an above-the-elbow plaster cast for three weeks. After a mean duration of follow-up of nine years (range, six to thirteen years), forty-one patients were evaluated with an interview, a physical examination, and radiographs made while a valgus load was applied to the elbow. RESULTS: The average score according to the system of The Hospital for Special Surgery was 91 points (range, 49 to 100 points), and thirty-one patients described their elbow function as good or excellent. Twenty-four patients had evidence of medial instability on radiographs made while a valgus load was applied to the elbow. Twenty-one patients had signs of degeneration of the joint, and twenty-five patients had ectopic ossification. Magnetic resonance imaging combined with arthrography was performed for the first twenty patients; eight had evidence of rupture of the medial collateral ligament, seven had generalized degenerative changes of the cartilage, and four had a chondral defect of the capitellum. (The study could not be completed for the remaining patient.) Medial instability on radiographs was correlated with signs of degeneration (p = 0.001), ectopic ossification (p = 0.01), a worse score according to the system of The Hospital for Special Surgery (p = 0.002), and persistent pain (p = 0.04). CONCLUSIONS: Posterolateral dislocation of the elbow joint can lead to persistent valgus instability that is associated with a worse overall clinical and radiographic result.

Adult↗
PubMedDate not supplied

[Role of wrist instability in the onset of pseudoarthrosis of the scaphoid bone].

INTRODUCTION: The most common fracture involving the wrist is a fracture of the scaphoid bone. Fracture of the scaphoid most frequently occurs in young adult male and usually involves the wrist of the scaphoid. There is a universal agreement that the majority of these fractures will heal if immobilized property and for a long period of time [1, 2]. In the treatment of these fractures much attention has been payed to bone damage and not to associated ligament injury. It is reported that the incidence of nonunion of scaphoid fractures is ten per cent and that the frequency of this complication remains essentially unchanged [3, 4]. Failure to improve the outcome suggests that the mechanisms and causes of this complication are poorly understood. Explanations of nonunion or delayed union of scaphoid bone are: poor initial treatment or even no treatment [3], delayed diagnosis [5], fragments displacement [5-8], improper immobilization [9], site and direction of the fracture [3] and wrist instability [8, 10]. AIM: The study was undertaken to analyse the influence of carpal instability on the development of scaphoid nonunion. METHOD: The study concerned 40 patients with painful nonunions of the scaphoid bone. Duration of nonunion was 1.43 year. There were 37 (92%) male and 3 (8%) female patients. Site and direction of the fracture, initial treatment and carpal collaps were analysed. Data processing was done for all examined patients (Table 1). RESULTS: Dominant hand was involved in 24 (60%) patients and nondominant hand in 16 (40%) subjects. Carpal collaps was present in 68% of patients. There were 14 (35%) untreated patients (Graph 1). Untreated fractures were statistically insignificant regarding the intensity of carpal collaps (p = 0.101; p > 0.05). The physical examination usually revealed focal tenderness, a palpable click with ulnar deviation, abnormal antero-posterior mobility with passive range of motion or a combination of these findings. Standard X-rays evaluated fracture location and carpal instability or collaps. There were 14 (35%) proximal third located fractures and 26 (65%) in the middle third of wrist (Graph 2). There was no statistically significant correlation between location of the fracture and presence of carpal collaps (p = 0.081; p > 0.05). DISCUSSION: There were 35 per cent overlooked fractures. Delay in diagnosis of a scaphoid fracture has been suggested as a significant factor in the development of nonunion [5, 7]. However, in our series of nonunions, non treatment does not occur frequently enough to be the critical factor. Most series report about 2/3 of nonunions occurring at the wrist [7, 9]. Our series shows a similar distribution, arguing against site as a critical factor. There appears to be a nearly uniform rate of nonunion in most of the reported series [7, 15, 16], regardless of the position of the wrist, whether or not the thumb was immobilized. Evidence of ligamentous injury in our series led us to conclude that scaphoid nonunion is consistently associated with carpal instability pattern. In our series 68% of nonunions associated with carpal collaps were present. We found no statistically significant correlation between carpal collaps and nontreated fractures or location of fracture site. Therefore, we concluded that carpal collaps was consistently present and, thus the critical factor in wrists with ununited scaphoid fractures.

Adolescent↗
PubMedDate not supplied

Pediatric shoulder instability: presentation, findings, treatment, and outcomes.

There is no one large study on pediatric shoulder instability. The purposes of this study were to characterize patients with shoulder subluxation or dislocation, the treatments provided, outcomes, and the predictors of good outcomes. Seventy shoulders in 66 patients were retrospectively reviewed, all with follow-up >2 years. The authors defined characteristics, treatment, outcomes, and associations between patient and treatment variables and outcome measures. Instability was associated with boys, adolescents, and trauma. Forty-two shoulders received physical therapy, and 28 required surgery. At follow-up, 54 of 70 described their shoulders as "better" or "much better," and 90% were performing at the same or higher levels of sports and work. Surgically treated patients were less likely to have recurrent instability or to report limitations. The current study is a large study of pediatric shoulder instability. Surgery improved stability, but overall, stability improved over time, with few patients having limitations at moderate- to long-term follow-up.

Adolescent↗
PubMed1999

[Disc degeneration and cervical instability].

OBJECTIVE: To evaluate disc degeneration and segmental instability in the cervical spine by comparing the magnetic resonance imaging assessment of disc degeneration with conventional plain radiographic evaluation with cervical segmental instability. METHODS: Two hundred sixty consecutive patients with suspected cervical spine disorders were analyzed for horizontal and angular displacements on lateral flexion and extension radiographs and disc degeneration on T(2)-weighted magnetic resonance images of the cervical vertebrae. RESULTS: In all intervertebral levels, the grade of disc degeneration increased significantly (P < 0.01) with age. Cervical instability was identified in 151 segments (14.5%) and correlated with Grade 1 and Grade 2 degeneration in the intervertebral discs (P < 0.01). CONCLUSIONS: Cervical segmental instability may indicate early degeneration of intervertebral disc in the cervical vertebrae.

Adult↗
PubMed2002

Effect of cervical instability in sympathetic cervical spondylosis.

OBJECTIVE: To investigate the etiology and treatment of sympathetic cervical spondylosis (SCS). METHODS: Twenty patients who with SCS had undergone operations for sympathetic cervical spondylosis were reviewed retrospectively from 1988 to 2000. Lateral views in flexion and extension of pre- and postoperative cervical X-ray were analyzed to quantify cervical instability. RESULTS: Cervical instability was detected at one level in seven patients, two levels in ten patients, three levels in three. Cervical instability mainly occurred at C(3)-C(4) and C(4)-C(5). Cervical epidural block had a short time effect in the greater part of patients. Cervical discectomy and fusion at unstable segment was carried out in all 20 cases. The effective rate was 90%. CONCLUSIONS: Cervical instability at C(3)-C(4) or C(4)-C(5) maybe an important factor in the etiology of sympathetic cervical spondylosis. Cervical epidural block may provide diagnostic information. Anterior cervical fusion were effective to treat sympathetic cervical spondylosis.

Adult↗
PubMed2003

[Ligament reconstruction for the chronic instability of the traumatic thumb carpometacarpal joint].

OBJECTIVES: We evaluated the results of ligament reconstruction performed for chronic instability of the traumatic thumb carpometacarpal joint. METHODS: Seven male patients with traumatic instability of the thumb carpometacarpal joint underwent ligament reconstruction with the use of the technique described by Eaton and Littler. The mean duration between the traumatic event and the operation was eight months. According to the radiological criteria by Eaton and Littler, five patients had stage I, and two patients had stage II disease. The mean follow-up period was 23 months. The results were assessed according to the criteria by Lane and Eaton. RESULTS: Postoperatively, the patients' grip strength and pinch strength increased by a mean of 40.4% (range 31% to 50%) and 75.4% (range 62% to 100%), respectively. No increases in the extent of arthrosis were observed in the carpometacarpal joint during the follow-up period. None of the patients developed morbidity associated with the functions of the flexor carpi radialis and the wrist. The results were excellent in four, and good in three patients. No complications occurred such as infection or recurrent instability, nor were there any problems related to the skin and Kirschner wires. CONCLUSION: Ligament reconstruction for the carpometacarpal joint of the thumb relieves pain and restores stability while preserving a functional range of motion in patients with chronic instability.

Adult↗
PubMed1992

Autotraction stress roentgenography for demonstration anterior and inferior instability of the shoulder joint.

A form of stress roentgenography is presented for the diagnosis of anterior and inferior shoulder instabilities. Stress is induced by anterioinferior traction concentrated on the shoulder during extension of the flexed hip, when patients hold their legs on the side being examined, with both hands. The anterior and inferior shifts of the humeral head in relation to the glenoid fossa then are measured from anteroposterior and modified axillary roentgenograms. This method was employed in 16 shoulders with recurrent anterior dislocation, 11 recurrent anterior subluxations, nine multidirectional instabilities, and 19 control shoulders. Mean anterior translations were 3 mm and 5 mm, and inferior translations were 7 mm and 10 mm for the control and recurrent dislocation groups, respectively. There were statistically no significant differences between those groups. In the recurrent anterior subluxations, the corresponding translations were of a completely different order, 21 mm and 19 mm, respectively, allowing the distinction from the controls and recurrent anterior dislocations in most cases. The shifts found in multidirectional instabilities, averaging 27 mm and 26 mm, respectively, were significantly greater than for the recurrent subluxations, but the differences were not great enough for accurate differential diagnosis in individual cases. Autotraction stress roentgenography of the shoulder may be of use in the diagnosis of recurrent anterior subluxations and anteroinferior multidirectional instabilities. It also gives good general views of the looseness of the glenohumeral joint.

Adolescent↗
PubMed1992

Scapulothoracic motion in normal shoulders and shoulders with glenohumeral instability and impingement syndrome. A study using Moiré topographic analysis.

Qualitative visual inspection and manual muscle testing are traditional methods of evaluation that may overlook subtle weakness of the axioscapular musculature. A modification of the standard technique of Moiré topographic analysis of spinal deformity was applied to assess axioscapular muscle function in 51 subjects: 22 asymptomatic individuals, 22 with shoulder instability, and seven with impingement syndrome. Static Moiré evaluation demonstrated scapulothoracic asymmetry or increased topography in 14% of asymptomatic subjects, compared with 32% and 57% in the instability and impingement groups, respectively. The dynamic Moiré test demonstrated an abnormal Moiré pattern in 18% of asymptomatic individuals, compared with 64% and 100% in the instability and impingement groups, respectively. Axioscapular muscle dysfunction is common with both instability and impingement syndrome of the shoulder, although it remains to be determined whether this represents a primary or secondary phenomenon.

Adult↗
PubMed2003

Non-traumatic shoulder instability in an athletic patient with a periglenoidal cyst and a glenoid labral tear.

A 34-year-old patient presented to our outpatient clinic with the chief complaint of shoulder instability, without any history of trauma. Physical examination revealed a painful apprehension test at 60 degrees, 90 degrees and 120 degrees but no objective sign of shoulder instability or hyperlaxity. MRI-scan showed a cyst over the anterior inferior glenoid rim. Arthroscopic findings were an enlarged capsule, a positive drive-through sign, a SLAP I lesion and a sublabral cyst at the anterior-inferior labrum. Detachment of the anterior labrum could be detected with a probe. The cyst's membrane was resected using a whisker shaver. The capsule and the anterior labrum were refixated with a suture anchor. Following capsular shrinking, there was no further laxity and the drive-through sign was diminished. After three months there was full range of active and passive motion. The patient had no subjective instability sensations. MRI showed no residuum of the cyst. Juxta-articular cysts are a known entity in large joints. There are different types of periarticular cysts. A ganglion cyst of the shoulder associated with glenohumeral instability has, to our knowledge, only been described twice. Our case suggests that mere excision of a juxtaglenoidal ganglion is not sufficient; reconstruction of the labrum must be performed to restore stability of the shoulder.

Adult↗