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PubMed2005

Kinematic and muscle activity characteristics of multidirectional shoulder joint instability during elevation.

Alterations of shoulder motion have been suggested to be associated with shoulder disorders. The objective of this study was to perform a 3D motion analysis (kinematic and electromyographical) of skeletal elements and muscles of shoulder joint in patients with multidirectional instability. Fifteen patients with multidirectional instability and 15 normal controls were investigated during continuous elevation in the scapular plane. The spatial coordinates of 16 anatomical points of the shoulder to determine kinematical parameters were quantified by an ultrasound-based motion analyzer. The activities of 12 muscles were measured by surface electromyography. Kinematic characteristics of motion were identified by scapulothoracic, glenohumeral, and humeral elevation angles; range of angles; scapulothoracic and glenohumeral rhythm; scapulothoracis, glenohumeral, and scapuloglenoid ratios; and the relative displacement between the rotation centers of the humerus and the scapula. The electromyographical characteristics of motion were modeled by the on-off pattern of muscle activity. Significant alterations in kinematical parameters were observed between patients and asymptomatic volunteers. The anterior, posterior, and inferior dislocations of shoulders with multidirectional instability could be properly modeled by the relative displacement between the rotation centers of the scapula and humerus. The shorter activity by m. pectoralis maior and all three parts of m. deltoideus and longer activity by m. supraspinatus, m. biceps brachii, and m. infraspinatus assure the centralization of the glenuhumeral head of a shoulder with multidirectional instability.

Adult↗
PubMed2005

Intra-articular volume assessment in glenohumeral instability.

It is commonly claimed that instability of the shoulder is associated with an enlarged joint volume. The purpose of our study was to assess the intra-articular volume in acute and chronic glenohumeral dislocation. Sixty-seven patients were examined by intra-articular infusion of saline solution. Three groups could be formed. Group 1 (n = 51) consisted of patients with first time traumatic dislocation, group 2 (n = 8) of cases with recurrent post-traumatic dislocation. The patients of group 3 (n = 8) suffered from impingement syndrome and served as the control group. The joint volume was correlated to the body surface area (BSA). We found a strong correlation between height, sex and intra-articular joint volume. There was no statistically significant difference in joint volume correlated to BSA between the three groups. There is no statistically significant difference in joint volume correlated to BSA in patients with traumatic anterior instability, chronic instability and individuals without glenohumeral instability.

Adolescent↗
PubMed2006

Chondral print on humeral head: an indirect sign of long head biceps tendon instability.

Long head biceps (LHB) tendon pathologies are becoming increasingly recognized causes of shoulder pain in the published literature. Instability of LHB presenting as dislocation or subluxation has been recently recognized as a possible cause of disabling pain or discomfort of the shoulder. A clinical diagnosis of LHB instability is very difficult and often confounding because of association with other shoulder pathologies. However, an early diagnosis of LHB instability is important in order to prevent the evolution of lesions of the biceps pulley until an internal anterosuperior impingement of the shoulder (ASI) and subscapular tear occur. The advent of arthroscopy contributed to enhance understandings. The goal of this article is to describe an arthroscopic sign, the chondral print on the humeral head, associated with a LHB instability, that when present can be very useful to help the surgeon to make the diagnosis of unstable LHB tendon.

Adult↗
PubMed1997

Quantitative gait analysis in patients with medial patellar instability following lateral retinacular release.

Medial patellar instability is a known possible complication following lateral retinacular release. Insufficient passive structures, muscle imbalance and an over-release of the lateral retinaculum with resection of the vastus lateralis tendon have been implied as a major cause of this problem. We report about the findings of quantitative gait analysis consisting of video recordings, three-dimensional motion analysis, dynamic electromyography and sampling of the ground reaction forces in two patients with medial patellar subluxation. Documentation of the gait functions together with observation of the patellar translation revealed the timing of the occurrence of the instability during level gait: a normal gait pattern with a sufficient quadriceps mechanism and a centred patella was seen during loading (weight acceptance), while the quadriceps muscle was active. Abnormal medial translation of the patella was observed during unloading of the leg while the knee was bending in preparation for the swing phase. This is a phase in the gait cycle when the quadriceps muscle is silent and the patella position is guided by the passive structures only. This finding weakens the argument of muscle imbalance as a cause for the patellar instability and stresses the importance of well balanced passive structures. This explains why a muscular rehabilitation programme is likely to fail as long as the passive structures allow the instability to occur.

Adult↗
PubMed1998

Indirect MR arthrography of anterior shoulder instability in the ABER and the apprehension test positions: a prospective comparative study of two different shoulder positions during MRI using intravenous gadodiamide contrast for enhancement of the joint fluid.

OBJECTIVE: The value of MRI for the evaluation of anterior shoulder instability can be enhanced by shoulder positions that stress the stabilising structures. The ABER position is one that has been described in combination with intra-articular gadopentetate dimeglumine arthrography. We believe that MRI in the Apprehension test position with 90 degrees abduction and maximal tolerable external rotation provides maximum tension on the anterior stabilising structures and with this technique it is sufficient to use indirect gadodiamide arthrography following intravenous injection of the contrast medium. The purpose of this study was to make a prospective comparative evaluation of the ABER and Apprehension test positions when using indirect arthrography with intravenous gadodiamide administration in shoulders with anterior instability. DESIGN AND PATIENTS: Sixteen patients with persistent anterior instability after recurrent shoulder dislocations were examined in an open MRI unit (0.2 T) following 0.1 mmol/kg of intravenous gadodiamide. Oblique axial T1-weighted imaging was used for analysis. Operative findings were used for correlation. RESULTS: Both the ABER and the Apprehension test position were useful techniques in detecting capsulolabral pathology and Hill-Sachs lesions. The Apprehension test position produced significantly better gadodiamide-enhanced joint fluid in the region of pathology in both the capsulolabral lesion and the Hill-Sachs lesion. It also visualised the size of the Hill-Sachs lesion significantly better than did the ABER position. CONCLUSION: MRI examination of anterior shoulder instability in the Apprehension test position was more beneficial than examination in the ABER position in visualising capsulolabral and Hill-Sachs lesions when using indirect arthrography.

Adolescent↗
PubMed2004

Quantitation of ligament laxity in anterior shoulder instability: an experimental cadaver model.

Three groups of cadaver specimens were studied. In group 1 (20 shoulders) glenohumeral ligaments were detached from the humerus until a permanent dislocation of the humeral head occurred in abduction plus external rotation. On the dislocated joint the ligament was reconstructed using a fascia lata lengthening plasty. After the plasty had been completed, the shoulder was reduced and instability checked in the same position. Then the capsule (including the plasty) was harvested and measured. In group 2 (20 shoulders), after the plasty had been completed in the same conditions as above, the capsule was progressively reduced by 2 mm steps until the instability disappeared. Then the capsule (including the plasty) was harvested and measured. In group 3 (12 shoulders), measurements of the head and of the capsule were done. To dislocate the shoulder the section of the three glenohumeral ligaments was required. Lengthening of the capsule in group 1 was 240-250%. In all cases shortening of the capsule led to the stabilization of the shoulder. After stabilization of the shoulder was reached a residual lengthening of 175-185% was recorded. In 3 out of 4 shoulders the amount of capsule shortening required to return to a stable shoulder was between 16 and 18 mm. This experiment did not reproduce the Bankart lesion; therefore it only concerns atraumatic instability. The main limitation of this model is the low lever force that may be used to dislocate the shoulder; consequently the elasticity of the glenohumeral ligament was not taken in account. The experimental values were likely over-estimated. Nevertheless the present results provide useful information for building an experimental model of atraumatic instability of the shoulder.

Aged↗
PubMed2006

Novel hMSH2, hMSH6 and hMLH1 gene mutations and microsatellite instability in sporadic colorectal cancer.

PURPOSE: To detect the hMSH2, hMSH6 and hMLH1 DNA mismatch repair gene mutations and microsatellite instability in somatic colorectal cancer. PATIENTS AND METHODS: The mutations of hMSH2, hMSH6, and hMLH1 genes, including microsatellite instability of BAT-26, BAT-40, D2S123, D5S346 and D17S250 were analyzed in 31 patients with colorectal. RESULTS: The results revealed that eight cases (25.8%) harbored mutations in DNA mismatch repair genes. Of these, five novel mutations including I237V in exon 4 of hMSH2, ins T at codon 1196 in exon 7 of hMSH6, and ins G at codon 154 in exon 6, N158H in exon 6, and del A at codon 257 in exon 9 of hMLH1 were identified. Moreover, several intronic polymorphisms, including c-g transversion at IVS-1 nt211 + 9 of hMSH2, del T in poly T track at IVS-6 nt3559-5, ATCT duplicate in IVS-7 nt 3642 + 35 and t-g transversion at IVS-10 nt4080 + 185 of hMSH6 were demonstrated in these patients. In addition, seven cases (22.5%) exhibited microsatellite instability (MSI). CONCLUSION: These results suggested that the inactivation of DNA mismatch repair genes and microsatellite instability may play a minor role in somatic colorectal cancer development.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Role of transarticular screw fixation in tuberculous atlanto-axial instability.

Prospective study of 27 consecutive cases of tuberculous atlanto-axial instability operated between 1998 and 2003. Early surgical stabilization of tuberculous atlanto-axial instability has gained popularity. This is largely due to success of chemotherapy in rapid control of infection. Although selective atlanto-axial fusion techniques are advocated in other indications, their role in tuberculosis remains confined to atlanto-axial wiring techniques that are mechanically unsound. The role of three-point rigid fixation using trans-articular screws (TAS) remains unclear. The objectives of this study are: (1) To define the role of trans-articular screws in tuberculous atlanto-axial instability based on radiological criteria. (2) To attempt to separate patients that can be treated by selective atlanto-axial fixation as against the standard occipito-cervical fusion (OCF). (3) Compare the clinical and radiological outcome parameters between the two groups. Twenty-seven consecutive patients of tuberculous atlanto-axial instability were operated between 1998 and 2003. The pattern of articular surface destruction and the reducibility of the atlanto-axial complex were assessed on plain radiographs and MRI. The reducibility of the C1-C2 joint was graded as reducible, partially reducible and irreducible. Pattern of the C1-C2 articular mass destruction was grouped as minimal, moderate and severe. The patients were divided into two surgical groups based on radiological findings and were treated with TAS (n=11) and OCF (n=16) fusion. The three-point fixation provided by the TAS allowed early brace free mobilization by 3 months with fusion rate of 100%. Fusion occurred in 83.16% in the OCF group. Implant failure occurred in two patients who underwent OCF. The patient satisfaction rate in the TAS group and the OCF group was 90.90 and 62.50%, respectively. Results in 27 consecutive patients demonstrate improved patient fusion and satisfaction rates in the TAS group. Judicious selection of patients for TAS fixation is possible with relatively few complications in tuberculosis of the atlanto-axial complex. This, however, requires a thorough understanding of the MRI pattern of involvement of the atlanto-axial complex that is difficult in non-endemic areas.

Adolescent↗
PubMed1998

Long-term outcome of patients suffering from clinical instability after microsurgical treatment of lumbar disc herniation.

A total of 39 patients suffering from clinical instability of the lumbar spine after microdiscectomy were evaluated for their long-term outcome. Included there were 21 (54%) male and 18 (46%) female patients with a mean age of 55 years. All had been operated on for a virgin single-level lumbar disc herniation between the years 1985-1989 and they were evaluated for the presence of lumbar instability in 1991. Clinical signs and symptoms of segmental instability were then detected in all patients, with the symptom of "apprehension" positive in 30. During the follow-up, 2 (5%) patients had been treated by lumbar spondylodesis. At the time of the present investigation, both of them gave the information that their low back pain and sciatica had diminished as compared to the prediscectomy situation; both were retired. The symptom of "apprehension" was negative in both. Of the remaining 37 patients, low back pain had completely recovered in 4 (11%) and diminished in 23 (62%) patients, while in 9 (24%) patients, back pain had remained unchanged and become worse in 1 (3%). Further, sciatica had completely recovered in 4 (11%) and diminished in 23 (62%) patients, while in 7 (19%) patients, sciatica had remained unchanged and become worse in 3 (8%). Only 14 (38%) of these patients were able to work. However, evaluated by the Oswestry Index, the overall outcome in daily activities had significantly improved in all 37 patients since 1991 (p = 0.01). The symptom of "apprehension" was now positive in 26 patients. A significant correlation was observed between the positivity of this test and the persistence of low back pain (p = 0.02) and a poor outcome in daily activities (p < 0.0001). Comfirming earlier observations, the findings of this study support the concept that patients with postoperative lumbar instability have a poor prognosis. Further studies are needed to define the optimal treatment for this problematic patient group.

Adult↗
PubMed2001

Surgery for upper cervical spine instabilities in children.

BACKGROUND: Due to the paucity of existing data with regard to surgical fusion of upper cervical spine instabilities in the paediatric population, we feel encouraged to report the results of our own series to provide additional information to the available body of literature. METHODS: Since 1991 N = 11 children underwent a total of N = 13 surgical procedures for N = 8 posttraumatic, N = 2 congenital and N = 1 postinfectious instabilities at a mean age of 10 years (range: 3-16 years). Transoral odontectomies, ventral odontoid screw-fixations, dorsal wiring or -clamping and transarticular screw-fixations were performed for stabilization and iliac crest bone graft used for fusion. Pain scores, neurological status and radiological results were documented at regular intervals (mean follow-up: 25.4 months). RESULTS: Stable fusion was achieved in all patients as documented on flexion/extension films and tomographies. At the latest follow-up N = 2 patients had improved and N = 9 were equal to their preoperative neurological status. Pain scores were improved in N = 9 patients. N = 2 children developed "bystander-fusion" after C0/2 wiring. N = 3 peri-operative complications occurred as transient neurological deteriorations. In one case this resulted from the resection of a lower brainstem tumour prior to the stabilization procedure. One was attributed to sublaminar wiring in the case of an os odontoideum and one occurred due to slippage of the halo orthosis after transoral odontectomy before definitive dorsal stabilization was carried out. INTERPRETATION: In accordance with the recent literature, we argue for the application of modern screw fixations and treatment algorithms as established for adults in upper cervical spine instabilities of older children. Techniques and indications remain problematic for those younger than 6 years and may have to be individualized in congenital instabilities.

Adolescent↗
PubMed2001

Roles of the anterior cruciate ligament and the medial collateral ligament in preventing valgus instability.

Both the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) are reported to prevent valgus instability of the knee. In this study, the anatomical mechanisms by which these ligaments prevent valgus instability were experimentally investigated. The valgus rotation angle and the magnitude of the medial joint space opening were measured in six cadaveric knees, using biplanar photography before and after the MCL and/or the ACL were severed. A significant increase in the valgus rotation angle and a large medial joint space opening were observed when the MCL was severed. An increase in the valgus rotation angle was also observed when the ACL was severed, but only a small medial joint space opening was present. The increase in the valgus rotation angle after ACL severance was nearly parallel to the increase in the internal rotation of the tibia. Thus, we concluded that both ligaments function to prevent valgus instability, but that the anatomical reasons for their function are different. The MCL prevents valgus instability by stopping an opening in the medial joint space. The ACL, on the other hand, prevents the internal rotation of the tibia. When the ACL is severed, the internal rotation increases, and causes the valgus rotation angle to also increase, despite the presence of only a small medial joint space opening.

Adult↗
PubMed2004

Biological features of sporadic colorectal carcinoma with high-frequency microsatellite instability: special reference to tumor proliferation and apoptosis.

BACKGROUND: We evaluated the relationship between biological behavior and microsatellite instability (MSI) status, with or without p53 status, in sporadic colorectal carcinoma. METHODS: MSI was analyzed with regard to biological features such as cellular proliferation and apoptotic cell death, in addition to clinicopathological features, in 87 patients with sporadic colorectal carcinoma. RESULTS: Fourteen (16.1%) of 87 tumors showed instability at two or more of the five loci examined (high-frequency MSI [MSI-H]). Four demonstrated instability at one locus (low-frequency MSI [MSI-L]), and 69 showed no instability (microsatellite-stable [MSS]). The MSI-H tumors tended to be located in the proximal colon and more often were mucinous carcinoma. The MSI-H tumors also tended to be in patients with multiple colorectal carcinomas and to demonstrate, rarely, an infiltrating growth pattern or venous invasion. The incidence of p53 protein overexpression in the MSI-H tumors was significantly lower than that in the MSI-L/MSS tumors (21% vs 54%). There was no significant difference in the proliferating-cell nuclear antigen (PCNA) labeling index (PI) or apoptotic index (AI) between the MSI-H and MSI-L/MSS tumors. The AI in the MSI-H tumors with p53 overexpression was significantly lower than that in the MSI-H tumors without p53 overexpression, and was also significantly lower than that in the MSI-L/MSS tumors with p53 overexpression. In the MSI-H tumors with p53 overexpression, no expression of BAX protein was found, and there was high expression of bcl-2 protein, resulting in a low BAX/bcl-2 ratio. CONCLUSION: In sporadic colorectal carcinoma, an MSI-H tumor with p53 protein overexpression may display aggressive biological features.

Adenocarcinoma↗
PubMed2005

Immunogenic hsp-70 is overexpressed in colorectal cancers with high-degree microsatellite instability.

PURPOSE: Colorectal cancers that display high-degree mi-crosatellite instability are associated with an improved prognosis and evidence of an activated host immune response. Molecular analyses have suggested that heat shock proteins, a family of proteins that have key immunologic functions, are upregulated in these cancers. We aimed to explore the expression of heat shock proteins 70 and 110 and their relationship to microsatellite instability, survival, and other clinicopathologic parameters. METHODS: Twenty-six colorectal cancers that displayed microsatellite instability were matched by age, stage, and site in the colorectum to 26 microsatellite-stable cancers. Immunohistochemistry was used to detect expression of both markers. RESULTS: The microsatellite-unstable group showed significantly higher expression of heat shock protein 70 than the microsatellite-stable group (P = 0.006), and patients undergoing curative resections for unstable cancers had improved prognosis compared with their stable counterparts (P = 0.026). Significantly, in a multivariate survival analysis, low or absent heat shock protein 70 expression was independently associated with a poor outcome (P = 0.001). CONCLUSIONS: Heat shock protein 70 has known functions that promote antitumor immune responses. Its overexpression in colorectal cancers with microsatellite instability may be pivotal to explaining these tumors' enhanced immunogenicity and improved prognosis.

Age Factors↗
PubMed1993

Arthroscopic diagnosis of scapho-lunate instability in the absence of X-ray abnormalities.

26 patients with at least one clinical symptom that could indicate a tear of the scapho-lunate interosseous ligament but normal static and dynamic radiographs were examined by arthroscopy. We found that a diagnosis of scapho-lunate instability could be established by dynamic manoeuvres during radio-carpal and mid-carpal arthroscopy. Five patients were found to have true scapholunate instability. Six tears of the interosseous ligament without instability were also detected but it was doubtful if the tear was the origin of the painful symptomatology. This experience suggests that dynamic manoeuvres during arthroscopy are superior to other methods in diagnosing scapholunate instabilities at the pre-radiographic stage.

Adolescent↗
PubMed1994

Carpal instability non-dissociative.

A retrospective study of 45 patients with symptoms of wrist pain and weakness with clinical evidence of instability is presented. These patients had normal intrinsic interosseous ligaments demonstrated arthrographically or surgically. They were followed for a minimum of 18 months and an average of 5.8 years. All patients demonstrated instability of the proximal carpal row which is referred to as carpal instability non-dissociative (CIND). Seven patients were treated non-operatively and 38 were treated operatively. Surgical management consisted of soft tissue reconstruction directed at the area of instability in 34 cases, joint levelling osteotomy in six, three of whom also had soft tissue reconstructions, and mid-carpal fusion in one. The overall good and excellent results were a disappointing 56% and there was no significant difference between the non-surgical and surgical groups. The best results were found in the ulna-minus CIND patients who underwent a joint levelling osteotomy, with 83% good and excellent results. CIND is associated with extrinsic ligamentous laxity; however, significant difficulty exists in locating the precise areas of maximum pathology. This accounts for the unpredictable results of treatment. As our understanding of the pathomechanics of CIND improves, the treatment will become more specific and the results should improve.

Adolescent↗
PubMed1990

Ulnar-sided perilunate instability: an anatomic and biomechanic study.

A staging system for ulnar-sided perilunate instability is presented based on a series of cadaver dissections and load studies. Stage I: partial or complete disruption of the lunotriquetral interosseous ligament, without clinical and/or radiographic evidence of dynamic or static volar intercalated segment instability deformity; stage II: complete disruption of the lunotriquetral interosseous ligament and disruption of the palmar lunotriquetral ligament, with clinical and/or radiographic evidence of dynamic volar intercalated segment instability deformity; and stage III: complete disruption of the lunotriquetral interosseous and the palmar lunotriquetral ligaments, attenuation or disruption of the dorsal radiocarpal ligament, with clinical and/or radiographic evidence of static volar intercalated segment instability deformity.

Adult↗
PubMed1995

Humeral avulsion of glenohumeral ligaments as a cause of anterior shoulder instability.

The avulsion of the glenohumeral ligament labral complex at the glenoid (Bankart lesion), as well as ligamentous laxity are well known causes of anterior shoulder instability. A lesser known entity, the humeral avulsion of glenohumeral ligaments (HAGL), was studied to determine its incidence and its role in anterior glenohumeral instability. Sixty-four shoulders with the diagnosis of anterior instability were prospectively evaluated by arthroscopy for intraarticular pathology, including Bankart, capsular laxity, and HAGL lesions. Six shoulders were found to have HAGL lesions (9.3%), 11 shoulders with generalized capsular laxity (17.2%), and 47 shoulders with Bankart lesions (73.5%). In patients with documented anterior instability without a demonstratable "primary" Bankart lesion, a HAGL lesion should be ruled out. This lesion is readily recognized arthroscopically, and an appropriate repair of this lesion can restore anterior stability to the patient. The pathological anatomy of the HAGL lesion and our treatment of this lesion is discussed.

Adolescent↗
PubMed2004

Arthroscopic findings in atraumatic shoulder instability.

PURPOSE: The goal of this study was to evaluate the intra-articular pathology in patients with atraumatic shoulder instability who did not respond to conservative treatment. TYPE OF STUDY: Prospective case series. METHODS: Of 226 patients treated for shoulder instability over a 2-year-period, 43 patients (average age, 27.5 years; 26 men and 17 women) were classified as having atraumatic instability. None had responded to physiotherapy. The intra-articular pathology was documented during diagnostic arthroscopy before the definitive surgical procedure. RESULTS: Three types of lesions of the capsulolabral complex were defined: incomplete labral lesions, pathologic elongation of the capsule or "non-Bankart lesions" (type I), classic Bankart lesions (type II), and complex lesions of the labrum and capsule (type III). Type I was found in 19 patients (44.2%); type II lesions were seen in 13 (30.2%); and type III in 11 (25.6%) patients. Hill-Sachs lesions were found in 26 shoulders (60.5%). Chondral lesions of the glenoid were seen in 10 shoulders (23%); SLAP lesions in 5 (11.7%); and partial, articular-side defects of the supraspinatus tendon in 3 (6.9%) patients. CONCLUSIONS: Atraumatic onset of shoulder instability does not imply the absence of intra-articular lesions, at least in patients not showing a response to physiotherapy. Arthroscopy is helpful to diagnose the definite intra-articular pathology. LEVEL OF EVIDENCE: Level IV.

Adult↗