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PubMed1997

Microsatellite instability in gastric cancer is associated with tumor location and family history in a high-risk population from Tuscany.

We studied the presence of microsatellite instability (MSI) in a series of 108 gastric cancers (GCs) previously identified in an epidemiological study carried out in a high-risk area around Florence. To investigate associations between MSI and GC family history, 34 cases (31.5%) who had a GC-affected first-degree relative were included in the series. A family history positive for colorectal cancer was reported quite rarely (5.6%). The analysis of 6 microsatellite loci in DNA from paired normal tissue and tumor samples microdissected from paraffin-embedded specimens revealed varying degrees of instability: 56 cases (51.8%) did not show instability at any of the 6 loci; 19 (17.6%) showed instability at 1 locus; 16 (14.8%) showed instability at 2 loci; 11 (10.2%) showed instability at 3 loci; 4 (3.7%) showed instability at 4 loci; and 2 (1.9%) showed instability at 5 loci. The replication error-positive (RER+) phenotype, defined as the presence of MSI at 2 or more loci, had a frequency of 30.6% (33 of 108) and tended to be positively associated with female sex, intestinal histological type, advanced tumor stage, vascular invasion, positive GC family history, and blood group of A type. No correlation emerged between age at diagnosis and RER+ phenotype, whereas a significant association with the RER+ phenotype was shown by the antral location. A multivariate analysis adjusting for a selected group of potential confounding factors confirmed the strong association of the RER+ phenotype with the antral location (P = 0.001) and with a positive GC family history (P < 0.05). Survival analyses at 5 and 8 years showed no difference between RER+ and RER- patients, even when corrected for stage distribution. By the microdissection technique, we also used microsatellite allele patterns to investigate intratumoral heterogeneity and genetic relationships between tumors and adjacent dysplasia and/or intestinal metaplasia. Areas of metaplasia and dysplasia demonstrated MSI only in cases with MSI-positive tumors. In MSI-positive tumors, there was consistent evidence of intratumoral microsatellite allele heterogeneity, indicating the presence of genetically divergent tumor cell clones within the same neoplasm.

Age Factors↗

PubMed2026

Genomic instability, postoperative recurrence and therapeutic vulnerabilities in resectable non‑small cell lung cancer (Review).

Resectable non‑small cell lung cancer (NSCLC) is managed largely according to anatomical stage, pathological risk and actionable driver alterations, yet these factors do not fully explain postoperative recurrence. Genomic instability may contribute to recurrence by promoting clonal diversification, intratumoral heterogeneity, occult dissemination, persistence of residual tumor cells, and immune escape. In the present review, chromosomal instability (CIN), copy‑number complexity, whole‑genome doubling, DNA repair defects, replication stress, and extrachromosomal DNA (ecDNA) were critically evaluated using a three‑axis translational framework encompassing biological consequences, potential clinical roles, and strength of evidence. Current evidence suggests that clonal diversity and copy‑number complexity have the clearest near‑term prognostic rationale. By contrast, CIN and whole‑genome doubling are supported more strongly by evolutionary and mechanistic rather than prospective clinical evidence. Defects in DNA repair, replication stress, and ecDNA represent potential therapeutic vulnerabilities, but their clinical relevance remains to be established. To date, no treatment‑predictive biomarkers based on genomic instability have been identified for resectable NSCLC. Direct clinical evidence linking any specific genomic instability feature to the presence or longitudinal dynamics of postoperative molecular residual disease (MRD) remains limited. Postoperative circulating tumor DNA‑defined MRD provides prognostic information more directly related to residual disease but remains assay‑dependent and should not be considered a genomic‑instability phenotype. Therefore, features of genomic instability should remain investigational and should not replace established clinical, pathological, or molecular decision‑making. Their near‑term value lies in refining biological risk models and generating testable hypotheses for biomarker‑defined perioperative trials.

Humans↗

PubMed2005

Accuracy of revised Bethesda guidelines, microsatellite instability, and immunohistochemistry for the identification of patients with hereditary nonpolyposis colorectal cancer.

CONTEXT: The selection of individuals for hereditary nonpolyposis colorectal cancer (HNPCC) genetic testing is challenging. Recently, the National Cancer Institute outlined a new set of recommendations, the revised Bethesda guidelines, for the identification of individuals with HNPCC who should be tested for microsatellite instability. OBJECTIVE: To establish the most effective and efficient strategy for the detection of MSH2/MLH1 gene carriers. DESIGN, SETTING, AND PATIENTS: A prospective, multicenter, nationwide study (the EPICOLON study) in 20 hospitals in the general community in Spain of 1222 patients with newly diagnosed colorectal cancer between November 1, 2000, and October 31, 2001. INTERVENTIONS: Microsatellite instability testing and MSH2/MLH1 immunostaining in all patients regardless of age, personal or family history, and tumor characteristics. Patients whose tumors exhibited microsatellite instability and/or lack of protein expression underwent MSH2/MLH1 germline testing. MAIN OUTCOME MEASURES: Effectiveness and efficiency of both microsatellite instability testing and immunostaining, either directly or previous selection of patients according to the revised Bethesda guidelines, were evaluated with respect to the presence of MSH2/MLH1 germline mutations. RESULTS: Two hundred eighty-seven patients (23.5%) fulfilled the revised Bethesda guidelines. Ninety-one patients (7.4%) had a mismatch repair deficiency, with tumors exhibiting either microsatellite instability (n = 83) or loss of protein expression (n = 81). Germline testing identified 11 mutations (0.9%) in either MSH2 (7 cases) or MLH1 (4 cases) genes. Strategies based on either microsatellite instability testing or immunostaining previous selection of patients according to the revised Bethesda guidelines were the most effective (sensitivity, 81.8% and 81.8%; specificity, 98.0% and 98.2%; positive predictive value, 27.3% and 29.0%, respectively) to identify MSH2/MLH1 gene carriers. Logistic regression analysis confirmed the revised Bethesda guidelines as the most discriminating set of clinical parameters (odds ratio, 33.3; 95% confidence interval, 4.3-250; P = .001). CONCLUSION: The revised Bethesda guidelines constitute a useful approach to identify patients at risk for HNPCC. In patients fulfilling these criteria, both microsatellite instability testing and immunostaining are equivalent and highly effective strategies to further select those patients who should be tested for MSH2/MLH1 germline mutations.

Adaptor Proteins, Signal Transducing↗

PubMed1998

[Management of old neglected posttraumatic acromioclavicular joint instability and arthrosis].

UNLABELLED: Resection arthroplasty of the AC joint was performed in 42 cases of osteoarthrosis and residual instability of traumatic origin including 26 shoulders with horizontal instability of more than half of the width of the clavicula and lesions of the deltotrapezoid fascial complex (Rockwood type II: 7; type III: 9; type IV: 17; type V: 9). 23 cases were treated with a sole Weaver-Dunn procedure. 26 cases with horizontal instability and lesions of the deltotrapezoid fascia (Rockwood IV and V type) were treated in 7 cases with the standard Weaver-Dunn procedure and in 19 cases with a modified Weaver-Dunn procedure in combination with a coracoclavicular (3 x 1) and acromio-clavicular (1 x 1) 1 mm PDS string augmentation and double breasting fascioplasty of the deltotrapezoid complex. RESULTS: Successful results (in Patte-Score) after a minimum follow-up of 2 years (mean: 32 months) were reached in 88.4% of cases with only Weaver/Dunn procedure with a significant difference of good and excellent results in the horizontally stable group (93.8%) versus the horizontally unstable group (57.2%). In the group with horizontal instability and Weaver-Dunn procedure and complex additional stabilization with fascioplasty and PDS augmentation, 89.5% excellent and good results were found. CONCLUSION: Cases with horizontal instability (type Rockwood IV and V) seem to be over-represented among patients with failed conservative treatment. Resection arthroplasty with ligament transposition after Weaver/Dunn gives excellent results in posttraumatic osteoarthrosis with mainly vertical and moderate horizontal instability. In cases with advanced horizontal instability after Rockwood IV and V injuries, almost equal results can be reached by an additional coracoclavicular and acriomioclavicular PDS augmentation with deltotapezoid fascioplasty.

Acromioclavicular Joint↗

PubMed1998

The dilemma with multiply reoperated knee instabilities.

The treatment of instability of the multiply reoperated knee is a complex problem. The causes for failure are numerous and include repeated trauma, insufficient fixation and non-anatomic placement of the graft, inadequate replacement material, isolated anterior cruciate ligament (ACL) reconstruction in complex knee instability or the use of a ligament prosthesis. With every surgical procedure, however, the anatomical and technical conditions become worse. Problems like degenerative changes, joint stiffness and gait abnormalities occur and often become a more focal point than the instability itself. The purpose of this paper is to present the problems and the dilemma of instability of the multiply reoperated knee and the possible solutions. Between 1976 and 1996, a total of 1752 ACL reconstructions were carried out in Munich and Hannover. Of these, 228 (13%) were revision, mostly of failed ACL reconstructions performed elsewhere. Since 1989, we have chosen the severest cases from this group (more than three operations on the same knee) for this study. Seventeen patients were investigated who had undergone up to 25 operations. The mean number of operations was 7. All primary operations were performed in other hospitals. In 10 cases only the ACL reconstruction was performed as a final procedure, mostly in combination with other procedures like medial meniscus replacement, extra-articular stabilization or arthrolysis. In the other cases operations such as osteotomies, arthrodesis or amputation were necessary. The results present the main dilemma in instability of the multiply reoperated knee since they were not successful in all patients. Finally, 15 patients report still having instability, pain or swelling in isolation or in combination. Nine patients were satisfied with their subjective results. Even after the socalled definitive procedures, certain complications arose. The main goal in the treatment of instability of the multiply reoperated knee is to avoid a series of operations, hospitalization and history of illness. General revision surgery for the entire complaint is not the aim of the treatment. The specific problem of the patient should be extracted from the complex situation, and this should be solved with the most limited procedure possible only.

Adult↗

PubMed2004

Failed back surgery syndrome: the role of symptomatic segmental single-level instability after lumbar microdiscectomy.

Segmental instability represents one of several different factors that may cause or contribute to the failed back surgery syndrome after lumbar microdiscectomy. As segmental lumbar instability poses diagnostic problems by lack of clear radiological and clinical criteria, only little is known about the occurrence of this phenomenon following primary microdiscectomy. Retrospectively, the records of 2,353 patients were reviewed according to postoperative symptomatic segmental single-level instability after lumbar microdiscectomy between 1989 and 1997. Progressive neurological deficits increased (mean of 24 months; SD: 12, range 1-70) after the initial surgical procedure in 12 patients. The mean age of the four men and eight women was 43 years (SD: 6, range 40-77). The main symptoms and signs of secondary neurological deterioration were radicular pain in 9 of 12 patients, increased motor weakness in 6 of 12 patients and sensory deficits in 4 of 12 patients. All 12 symptomatic patients had radiological evidence of segmental changes correlating with the clinical symptoms and signs. All but one patient showed a decrease in the disc height greater than 30% at the time of posterior spondylodesis compared with the preoperative images before lumbar microdiscectomy. All patients underwent secondary laminectomy and posterior lumbar sponylodesis. Postoperatively, pain improved in 8 of 9 patients, motor weakness in 3 of 6 patients, and sensory deficits in 2 of 4 patients. During the follow-up period of 72+/-7 months, one patient required a third operation to alleviate spinal stenosis at the upper end of the laminectomy. Patients with secondary segmental instability following microdiscectomy were mainly in their 40s. Postoperative narrowing of the intervertebral space following lumbar microdiscectomy is correlated to the degree of intervertebral disc resection. It can therefore be concluded that (1) patients in their 40s are prone to postoperative narrowing of the intervertebral disc space and hence subsequent intervertebral instability and (2) that a small extent of intervertebral disc resection and preservation of the "segmental frame" may be beneficial in those patients. The present study demonstrated for the first time that the degree of extensive operative techniques in microdiscectomy increased the risk of subsequent segmental instability. In addition, narrowing of the intervertebral space of more than 30% represents a clear radiological sign of segmental instability.

Adult↗

PubMed1990

Arthroscopy of the wrist: anatomy and classification of carpal instability.

Carpal instability can be defined as the lack of ligamentous and skeletal support adequate to maintain a wrist stable to external forces of pinch and grasp. This instability may be static or dynamic. It has been classified as (a) carpal instability, dissociated (CID), a situation in which one or more of the ligaments are torn, and (b) carpal instability, nondissociative (CIND), a situation in which the ligaments are intact but stretched. Carpal instability can also be the result of carpal bone malalignment from various causes. Arthroscopy can be particularly useful in assessing carpal instability, however arthrography with contrast medium, fluoroscopy, and stress loading should precede this arthroscopic assessment. Arthroscopy allows visualization of the volar radiocarpal and ulnocarpal ligaments of the wrist, and the arthroscopic examination can be combined with manual manipulation of the carpal bones to detect laxity of those ligaments, to examine stability of the scapholunate and lunotriquetral interosseous ligaments, and to show instability of the distal radioulnar joint.

Arthroscopy↗

PubMed2006

Shoulder instability and related rotator cuff tears: arthroscopic findings and treatment in patients aged 40 to 60 years.

PURPOSE: To report our experience with the arthroscopic treatment of patients aged 40 to 60 years with rotator cuff lesions, shoulder instability, or both, and to seek a relationship among capsular-labral complex lesions, cuff tears, number of dislocations, and patient age. TYPE OF STUDY: Case series. METHODS: From January 2000, all patients aged between 40 and 60 years undergoing an arthroscopic procedure for rotator cuff lesions, shoulder instability, or both were divided into 3 cohorts: shoulder instability (group I), complete cuff tear (group C), and instability and complete cuff tear (group IC). In May 2002 there were 50 patients per group. Arthroscopic findings were analyzed using the Pearson correlation coefficient and the chi2 test to seek correlations between the lesions. The Student t test was used to highlight significant differences between preoperative and postoperative scores. RESULTS: There was a strong correlation between the rising number of dislocations and associated lesions of the supraspinatus and infraspinatus (P < .001); this correlation became stronger after 7 episodes of dislocation (P < .0001). There was no correlation between capsular or Bankart lesion and presence or absence of rotator cuff tears (P > .5). Two cases of recurrence of instability were recorded in group IC. Postoperatively, the Constant and Rowe scores rose significantly and consistently in all patients (P < .001). CONCLUSIONS: Rotator cuff tears and glenohumeral instability appear to be closely related. Patient age and number of dislocations do not appear to correlate with Bankart or capsular lesions, whereas posterosuperior cuff tears seem to be influenced by number of dislocations. Although data do not permit us to conclude whether repair of the sole cuff tear can achieve shoulder stability nor whether shoulder stabilization alone can resolve the instability, treatment of both lesions should be performed arthroscopically. LEVEL OF EVIDENCE: Level IV, case series.

Adult↗

PubMed2004

[Radiological and clinical study of the ulna's end instability after Sauvé-Kapandji procedure].

The aim of the study was to analyse the ulnar proximal stump's behaviour after Sauvé-Kapandji procedure. The procedure was performed for post-traumatic disorders of the distal radio-ulnar joint. This is a retrospective study of 14 patients. The mean age of patients at the operation was 49 years. Most of them began immediate mobilisation into pronation and supination. After a 5 year follow-up period, the clinical examination was centred on the ulnar proximal stump. An original radiologic study was made with static and dynamic X-Ray. Seven patients indicated pain on the ulnar stump during pronosupination. A clunk on the ulnar side of the wrist was noticed by three patients and an instability of the ulnar stump was observed two times. Clinically, there were a sagittal instability in all patients and a frontal instability four times. The sagittal instability was confirmed by dynamic X-Ray on each occasion, but the frontal instability was never confirmed. Every patient had instability of the ulnar stump; however, it was well tolerated. In practice, 12 patients were satisfied or very satisfied (86%). Instability of the proximal ulnar stump remains a problem, because it occurs despite a strict technique.

Female↗

PubMed1994

Sidebending versus flexion-extension radiographs in lumbar spinal instability.

Flexion-extension radiography is accepted as an effective method for the diagnosis of lumbar spinal instability, but the usefulness of sidebending films is less well known. Flexion-extension and sidebending radiographs of 300 patients with clinically suspected lumbar spinal instability were analyzed retrospectively. Generally used criteria for lumbar spine instability were applied in the film analysis. Although flexion-extension and sidebending films were statistically significantly interrelated in the diagnosis of instability, intertechnique agreement remained poor. Flexion-extension films more frequently revealed signs of instability than sidebending films; 84 vs 50 patients. Signs of instability on sidebending films showed the best correlation with the findings of angular motion and posterior sliding instability on flexion-extension films. Sidebending films are complementary to flexion-extension films but are unlikely to be helpful on a routine basis.

Adolescent↗

PubMed2001

Glenohumeral joint kinematics related to minor anterior instability of the shoulder at the end of the late preparatory phase of throwing.

OBJECTIVE: The first aim of this study was an approach to quantify the 3D kinematics of the glenohumeral joint referred to the joint surfaces. The method was used to study the glenohumeral patho-arthrokinematics related to minor anterior instability at the end of the late preparatory phase of throwing. STUDY DESIGN: Using a finite helical axis approach, arthrokinematics focused on: (i) the rotations and shift of the humeral head on the glenoid cavity, and (ii) the migration of contact of the articular surfaces. BACKGROUND: Controversy still exists whether the clinical syndrome called 'minor anterior glenohumeral instability' can be validly termed as an instability. METHODS: Helical CT-data of discrete shoulder positions were three-dimensionally reconstructed. Based on humeral and scapular sets of skeletal landmarks, rotation matrices and translation vectors were estimated and processed in glenohumeral finite helical axes. The finite helical axis parameters of rotation, shift and direction were related to a co-ordinate system embedded on the glenoid, whereas the position of the finite helical axis was related to the articulating surface of the humeral head. RESULTS: From 90 degrees abduction and 90 degrees external rotation to full cocking (90 degrees abduction with full external rotation and horizontal extension), the humeral head in the normal shoulders did not externally/internally rotate on the glenoid. In contrast, a large external rotation component was found in the minor unstable shoulders. The geometrical centre of the humeral head of the normal shoulders translated into a posteriorized position on the glenoid, whereas in minor anterior instability it translated centrally on the glenoid. CONCLUSIONS: Compared with in vitro biomechanical research which states that towards full cocking the anterior part of the inferior glenohumeral ligament limits anterior translation and external rotation of the humeral head on the glenoid, the results suggest in minor anterior instability a dysfunction of the anterior part of the inferior glenohumeral ligament. RELEVANCE: The results indicate that the so-called 'minor anterior glenohumeral instability syndrome' can validly be stated as an instability problem. The results also indicate that the glenohumeral joint does not move consistently as a ball-and-socket joint, meaning that the concave-convex rules for glenohumeral joint mobilization need 'evidence-based' adjustments.

Adult↗

PubMed2002

Segmental lumbar spine instability at flexion-extension radiography can be predicted by conventional radiography.

AIM: To identify plain radiographic findings that predict segmental lumbar spine instability as shown by functional flexion-extension radiography. MATERIALS AND METHODS: Plain radiographs and flexion-extension radiographs of 215 patients with clinically suspected lumbar spine instability were analysed. Instability was classified into anterior or posterior sliding instability. The registered plain radiographic findings were traction spur, spondylarthrosis, arthrosis of facet joints, disc degeneration, retrolisthesis, degenerative spondylolisthesis, spondylolytic spondylolisthesis and vacuum phenomena. Factors reaching statistical significance in univariate analyses (P < 0.05) were included in stepwise multiple logistic regression analysis. RESULTS: Degenerative spondylolisthesis (P = 0.004 at L3-4 level and P = 0.017 at L4-5 level in univariate analysis and odds ratio 16.92 at L4-5 level in multiple logistic regression analyses) and spondylolytic spondylolisthesis (P = 0.003 at L5-S1 level in univariate analyses) were the strongest independent determinants of anterior sliding instability. Retrolisthesis (odds ratio 10.97), traction spur (odds ratio 4.45) and spondylarthrosis (odds ratio 3.20) at L3-4 level were statistically significant determinants of posterior sliding instability in multivariate analysis. CONCLUSION: Sliding instability is strongly associated with various plain radiographic findings. In mechanical back pain, functional flexion-extension radiographs should be limited to situations when symptoms are not explained by findings of plain radiographs and/or when they are likely to alter therapy.

Adolescent↗

PubMedDate not supplied

[MR-based 3D-analysis of the pathomechanics of traumatic and atraumatic shoulder instability].

AIM: Until now it is unknown to what extent malpositioning of the scapula is a relevant factor in shoulder instability that should be considered in therapy. The objective was to analyse 3D-scapular kinematics and humeral head (de-)centering in patients with atraumatic and/or traumatic shoulder instability and to investigate the correlation between the two factors. METHOD: The shoulders of 28 healthy volunteers and of 14 patients each with atraumatic or traumatic instability were examined in various arm positions - with and without muscle activity - using open MR imaging. After 3D reconstruction, analyses of scapular kinematics and glenohumeral translation were performed. RESULTS: In atraumatic unstable shoulders, the scapular position [30 degrees of abduction: scapulo-humeral rhythm: 3.5 +/- 2.6 : 1 vs. healthy 2.4 +/- 1.3 : 1; internal rotation: 59 +/- 9 degrees vs. healthy 49 +/- 3 degrees (p < 0.05)] and humeral head position was significantly decentered in both planes (p < 0.05). While the correlation between the two factors was high during passive elevation (r = 0.60-0.87), it was low during muscular activity (r = 0.25-0.62). In patients with traumatic instability no alterations of the scapula kinematics were observed. Significant humeral head decentering (p < 0.05) occurred only during abduction and external rotation. CONCLUSIONS: Patients with atraumatic instability demonstrated significant alterations of scapular kinematics and decentering of the humeral head. In traumatic instability a decentering occurred only in specific arm positions with no changes in scapula position. Because of the high correlation between the two factors, physiotherapeutic strategies for the scapula-stabilising muscles should be adapted to the direction of instability.

Adolescent↗

PubMed1991

Prolonged peroneal reaction time in ankle instability.

The peroneal reflex time to sudden ankle inversion and the postural control of 15 athletes with functionally instable ankles were compared with 15 stable controls. A trapdoor produced sudden ankle inversion. Surface electrodes recorded electromyographic activity of the peroneal muscles. Postural sway was expressed by a transverse sway value obtained during single limb stance on a force plate. Increased postural sway was found in subjects with functional instability (p less than 0.01). This is in accordance with previous studies. Functionally instable subjects also displayed an increased peroneal reaction time (p less than 0.01) supporting the theory that functional instability is induced by a proprioceptive reflex defect. Nine of the 15 instable subjects were unilaterally instable and showed lower peroneal reaction time and postural sway values for the stable ankle, but the difference was not significant. There was a high degree of correlation between postural sway and peroneal reaction time (Spearman's rho = .92). In ten functionally instable athletes tested with and without ankle taping, it could not be verified that a reflex enhancing effect of taping occurs through stimulation of cutaneous afferents.

Adult↗

PubMedDate not supplied

Iliotibial band reconstruction for treatment of glenohumeral instability associated with irreparable capsular deficiency.

The surgical management of patients with recurrent anterior instability after failed surgery can be complicated by the loss of capsular tissue and, in some cases, irreparable tears of the subscapularis tendon. We describe a new surgical technique for reconstruction of the capsular ligaments using the iliotibial band (ITB) to reconstruct deficient capsular tissues, and we report the results of 7 patients. All patients had prior surgery, with a mean of 2.2 procedures, and recurrent instability as the primary indication for their index and revision surgeries. After ITB reconstruction, the patients demonstrated significant improvement in their American Shoulder and Elbow Surgeons (ASES) score (P =.0004), and no patient had any persistent symptoms of instability. Physiologic range of motion and function were maintained. We would recommend our method of ITB reconstruction for patients with instability and capsular deficiency after failed surgery and believe that this procedure has advantages over those previously described. Capsular deficiency and persistent instability after prior surgery can occur after prior open or arthroscopic surgery. Capsular deficiency has been described after thermal capsulorrhaphy and is thought to represent excessive thermal injury and tissue necrosis. After open capsulorrhaphy, capsular deficiency can be associated with subscapularis tendon deficiency.(4,6-8,12,13) Capsular deficiency occurring after either open or arthroscopic surgery presents a difficult surgical challenge. The purpose of this case series is to evaluate our experience in the surgical management of recurrent glenohumeral instability after surgery initially performed for treatment of glenohumeral instability that failed and is associated with irreparable tears of the subscapularis and capsular deficiency. The primary objectives of this study are to describe the surgical technique for capsular reconstruction with ITB and to report the clinical results in 7 patients.

Adult↗

PubMed2000

Classification and evaluation of recurrent instability of the elbow.

The clinical presentation, diagnosis, radiographic features, mechanism, pathologic changes, and treatment of elbow instability are understood better now. Elbow instability can be classified according to five criteria: (1) the timing (acute, chronic or recurrent); (2) the articulation(s) involved (elbow versus radial head); (3) the direction of displacement (valgus, varus, anterior, posterolateral rotatory); (4) the degree of displacement (subluxation or dislocation); and (5) the presence or absence of associated fractures. Posterolateral rotatory instability is the most common pattern of elbow instability, particularly that which is recurrent. Posterolateral rotatory instability can be considered a spectrum consisting of three stages according to the degree of soft tissue disruption. Patients typically present with a history of recurrent painful clicking, snapping, clunking, or locking of the elbow and careful examination reveals that this occurs in the extension portion of the arc of motion with the forearm in supination. There are four principle physical examination tests. The most sensitive is the lateral pivot-shift apprehension test, or posterolateral rotatory apprehension test, just as the anterior apprehension test of the shoulder is the most sensitive test for a patient with shoulder instability. Next is the lateral pivot-shift test, or posterolateral rotatory instability test. Reproducing the actual subluxation and the clunk that occurs with reduction usually can be accomplished only with the patient under general anesthesia or occasionally after injecting local anesthetic into the elbow. The third test is the posterolateral rotatory drawer test, which is a rotatory version of the drawer or Lachman test of the knee. The final test is the stand up test as reported by Regan. The patient's symptoms are reproduced as he or she attempts to stand up from the sitting position by pushing on the seat with the hand at the side and the elbow fully supinated. A lateral stress radiograph can show the rotatory subluxation.

Elbow Joint↗

PubMed2002

Classification of glenohumeral joint instability.

Shoulder instabilities have been classified according to the etiology, the direction of instability, or on combinations thereof. The current authors describe a classification system, which distinguishes between static instabilities, dynamic instabilities, and voluntary dislocation. Static instabilities are defined by the absence of classic symptoms of instability and are associated with rotator cuff or degenerative joint disease. The diagnosis is radiologic, not clinical. Dynamic instabilities are initiated by a trauma and may be associated with capsulolabral lesions, defined glenoid rim lesions, or with hyperlaxity. They may be unidirectional or multidirectional. Voluntary dislocation is classified separately because dislocations do not occur inadvertently but under voluntary control of the patient.

Chronic Disease↗

PubMed1985

Segmental instability. Rationale for treatment.

Segmental instability, secondary to spinal degeneration, is a controversial topic. Based on current clinical, radiographic, and biomechanical considerations, this condition is classified as axial rotational, translational, retrolisthetic, and postsurgical instability syndromes. Each of these conditions would be expected, if untreated, to progress to a fixed deformity in which the clinical symptoms of spinal stenosis would predominate. The classification of these four types of instability suggests a need for specifically tailored fusion techniques in those patients who fail to respond to conservative treatment. Antitorsion facet fusion is suggested for axial rotatory instabilities; anterior (or posterior) interbody fusion for translational instabilities; and fusion in flexion (Knodt rods or facet fusion) for retrolisthetic instabilities. Post-surgical instability syndromes require carefully selected approaches based on the overall pathology. Application of specific fusion techniques, in carefully selected patients, may improve the currently unacceptable low rate of success from such operations.

Adult↗