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PubMed2006

Postural control deficits in participants with functional ankle instability as measured by the balance error scoring system.

OBJECTIVE: To determine if postural control deficits are present in participants with functional ankle instability (FAI) as measured by the Balance Error Scoring System (BESS). DESIGN AND SETTING: We used a between-groups design to assess postural control. All testing was conducted in a university athletic training facility. PARTICIPANTS: Sixty collegiate Division I athletes were included in this study. Thirty participants had functional ankle instability and thirty participants had no history of ankle injuries. MAIN OUTCOME MEASUREMENTS: Postural control was measured using the BESS. The BESS test battery requires participants to stand unsupported on two different surfaces (firm and foam) in three different stances (double, single, and in tandem). Each condition lasted 20 seconds. The number of errors were calculated for each individual condition and then summed to produce a total BESS score. RESULTS: We found a significant group by condition interaction (F5,290 = 5.12, P < 0.001) and significant main effects for group (F1,58 = 16.01, P < 0.001) and condition (F5,290 = 228.88, P < 0.001). Post hoc analyses revealed that subjects with functional ankle instability scored more errors (poorer balance) on the single stancefirm condition (2.9 +/- 2.1 versus 1.6 +/- 1.3 errors), tandem stancefoam condition (4.3 +/- 2.4 versus 2.7 +/- 1.6 errors), single stancefoam condition (7.0+/-1.6 versus 5.6 +/- 1.8 errors), and total BESS score (15.7 +/- 6.0 versus 10.7 +/- 3.2). CONCLUSIONS: Postural control deficits were identified in participants with functional ankle instability using the BESS. These deficits could be a contributing factor to the repeated episodes of instability and giving way that often occurs following an inversion ankle sprain. These results suggest the BESS, traditionally used for monitoring recovery from mild head injury, may also be useful in screening athletes for postural deficits following lower extremity injury.

Adolescent↗
PubMed2004

Incongruity versus instability in the etiology of posttraumatic arthritis.

The etiology of posttraumatic arthritis is understood poorly but it clearly has a pathomechanical component. Posttraumatic arthritis likely results from irreversible cartilage damage sustained at the time of injury and chronic cartilage overloading resulting from articular incongruity and instability. However, the relative importance of instability and incongruity is unknown. Clinical studies show that the hip, knee, and ankle tolerate incongruity differently. However, all three joints poorly tolerate instability. Basic mechanical studies have shown that static loading of articular surface incongruities have caused relatively modest increases in contact pressure. However, static testing poorly replicates normal viscoelastic properties of cartilage, which may mask important transient stress elevations that occur during motion. Static tests also ignore potential abnormal loads that may accumulate throughout a motion cycle. We review the clinical and basic scientific evidence linking incongruity and instability to posttraumatic arthritis. Preliminary data from a newly developed dynamic ankle testing device are presented. Dynamic testing allows measurement of transient contact loads and loading rates that occur through the entire motion cycle and it opens the door to measure mechanical abnormalities associated with instability.

Ankle Injuries↗
PubMedDate not supplied

Treatment of ankle instability in children and adolescents with a modified Chrisman-Snook repair: a clinical and patient-based outcome study.

Ligamentous injuries to the lateral ankle complex, although rare in the child with open physes, increase with age and are seen with considerable frequency in late childhood and adolescence. In athletic, ligamentously lax individuals, recurrent sprains may lead to ligament attenuation and instability. When instability becomes chronic and interferes with everyday activity, reconstruction is indicated. The literature on reconstruction addresses primarily the adult population, with minimal guidance in treating the child and adolescent. The authors report their experience with 48 reconstructions performed in patients aged 8 to 17 years (mean 14.5 years) over a 12-year period. Mean follow-up was 6.5 years. All patients failed to respond to conservative treatment, including casting or bracing and physical therapy. All had disabling instability. All had a positive drawer sign clinically, and all but one had significant talar tilt on preoperative stress radiographs. A modification of the Chrisman-Snook procedure was used. Forty-four ankles in 38 patients were available for clinical and radiographic re-evaluation. One patient with generalized systemic ligamentous laxity required bilateral repair for failure of previous Evans procedures 8 years earlier; the remaining patients had primary repairs and remain asymptomatic. Each has a negative drawer sign and a reduction of talar tilt from a preoperative average of 14.5 degrees to a postoperative average of 4 degrees, based on stress radiographs. An outcomes questionnaire was administered to all patients, who subjectively rated their pain and instability at extremely low levels (1/10) and their function at a high level (8/10). All patients had their expectations met regarding the results of surgery. There was no radiographic evidence of degenerative arthritis at follow-up. The authors recommend this as an excellent means of treating children with chronic ankle instability who have failed to respond to conservative treatment. The authors have modified Chrisman's procedure by using a much smaller incision and improved graft isometry.

Adolescent↗
PubMedDate not supplied

Transarticular screws in the management of C1-C2 instability in children.

C1-C2 instability is a challenging problem in the pediatric population. Small patient size and poor healing potential in the at-risk groups, such as patients with Down syndrome and os odontoideum, make fixation difficult. Instability in patients with Down syndrome is a common problem, and traditional methods of fixation have a high complication rate and are a challenge given the frequent anatomic abnormalities such as an incomplete or hypoplastic arch, os odontoideum, and incomplete passive reduction. The purpose of this study was to review our experience of transarticular screw use in pediatric patients and to define the potential applications of this technique in pediatric C1-C2 instability. Twelve patients, with C1-C2 instability managed with transarticular screws at the authors' institution, were reviewed. The youngest patient treated was 5 years old with a mean age for the group of 11.5 years. The group consisted of 3 patients with Down syndrome and 9 patients with os odontoideum. Three of the patients with os odontoideum failed previous posterior wiring. Two patients presented with an acute spinal cord injury in the setting of chronic instability. Preoperative computed tomography or magnetic resonance imaging was used in all patients to define the vascular and bony anatomy. No further surgery has been required at a mean follow-up of 5.1 years in all patients. Although vertebral size and congenital anomalies may make screw positioning challenging, the technique allows fixation in the absence of a complete posterior arch of C1 and eliminates the need for instrumentation in the canal. This technique also provides a high fusion rate in a complicated patient population.

Adolescent↗
PubMed2006

Segmental instability in cervical spondylotic myelopathy with severe disc degeneration.

STUDY DESIGN: A retrospective study was conducted. OBJECTIVE: To investigate relationships between severe disc degeneration (SDD) and segmental instability in cervical spondylotic myelopathy (CSM) and to discuss surgical treatment for CSM with severe disc degeneration. SUMMARY OF BACKGROUND DATA: Information on relationships between segmental instability and spinal cord compression in CSM with severe disc degeneration is scarce. METHODS: Radiographs and magnetic resonance images of patients with CSM with (n = 42) and without (n = 75) SDD were reviewed retrospectively. Cervical instability and spinal cord compression factors were analyzed. Outcomes of anterior cervical decompression and fusion (ACDF) and expansive laminoplasty (ELAP) were evaluated in medical records of follow-up clinics. RESULTS: Segmental instability was found in 71.4% of patients with SDD and 22.7% of patients without SDD. Spinal cord compression was found at the intervertebral space of SDD and upper adjacent disc space. The recovery rate of ACDF and ELAP was 60.8% and 57.1%, respectively. CONCLUSION: The upper adjacent vertebra above SDD has inclination of segmental instability. There is static spinal cord compression in intervertebral spaces of SDD and dynamic compression in upper adjacent intervertebral spaces. Multilevel anterior cervical decompression and fusion or expansive laminoplasty should be used for surgical treatment.

Aged↗
PubMed2004

Treatment of dynamic scaphoid instability.

BACKGROUND: Chronic wrist pain attributable to scaphoid instability without fixed deformity (dynamic instability) presents a treatment dilemma. The diagnosis usually is delayed, missing the opportunity for direct repair. The intercarpal fusion, tenodesis, and capsulodesis procedures create a fixed deformity. This report presents an outcome study of a new treatment for dynamic scaphoid instability that spanned more than 5 years. METHODS: Arthroscopic evaluation was used to confirm the diagnosis for 105 wrists of 102 patients who had experienced wrist pain for an average of 24.4 months. The treatment for these patients involved transferring two thirds of the extensor carpi radialis longus through the distal pole of the reduced scaphoid volarly to the intact flexor carpi radialis. The postoperative follow-up period averaged 63 months. RESULTS: The average grip strength increased by 65%. The average active wrist extension-flexion increased by 9%, with an average radial deviation loss of 6 degrees. The overall results, as measured by the modified Green and O'Brien clinical wrist scale, were as follows: excellent (49%), good (24%), and fair (26%). Good to excellent results were reported by 85% of the patients. Pain relief was reported by 94% of the patients, and 93% of the patients would recommend the procedure to others. CONCLUSIONS: Scaphoid instability without fixed deformity is a complex problem. Conventional treatments have drawbacks. The new technique produced positive results that are quite promising for the management of dynamic scaphoid instability.

Arthroscopy↗
PubMed1998

Surgical treatment of concomitant chronic ankle instability and longitudinal rupture of the peroneus brevis tendon.

Chronic lateral ankle instability can be associated with a longitudinal rupture of the peroneus brevis tendon. Patients with these problems have atypical posterolateral or retromalleolar pain, as well as clinical signs of ligamentous instability. This injury is frequently concomitant with lateral ligament injuries and the injury mechanism is similar; however, the tendon rupture is often missed. Laxity or insufficiency of the superior peroneal retinaculum allows the anterior part of the peroneus brevis tendon to ride upon the sharp posterior fibular edge, resulting in a longitudinal rupture of the tendon. We report on the results after surgical treatment in nine patients (10 ankles) with combined instability of the lateral ankle ligaments and longitudinal rupture of the peroneus brevis tendon. All these patients underwent surgical repair of the peroneus tendon, reconstruction of the superior peroneal retinaculum, removal of the sharp posterior edge of the fibula and correction of the ligamentous instability of the anterior talofibular and calcaneofibular ligaments. One constant finding at surgery was a longitudinal intratendineal rupture of the peroneus brevis tendon combined with insufficiency of the superior peroneal retinaculum and insufficiency of the lateral ligaments. At follow-up 3 (2-5) years post-operatively, the functional results were excellent or good in nine ankles and fair in one. All the patients with excellent or good results had resumed their preinjury activity level. We conclude that this lesion should be suspected in patients with lateral ligamentous instability, combined with retromalleolar pain. In these cases, it is important to address both the tendon rupture and the ligamentous insufficiency.

Adolescent↗
PubMed1998

Atraumatic shoulder instability. Discussion of classification and results after capsular imbrication.

This study consists of 27 shoulders in 24 patients whose atraumatic shoulder instability was treated with the imbrication procedure described by Rockwood. Follow-up after 2 years or more showed the following results: 37% excellent, 30% good, 15% fair and 18% poor (Rowe score). No statistically significant differences in the results were observed between the dominant and non-dominant arm, nor in post-operative return to sports activities. Those with voluntary instability had more laxity at follow-up and tended to have poorer results. Those with unidirectional laxity had only good or excellent results and showed no post-operative laxity. We found no other reliable indication of the results of surgery. The difficulties of classifying shoulder instability by such factors as trauma, laxity and direction of instability are discussed. Overall, we consider capsular imbrication to be a good treatment for involuntary atraumatic shoulder instability.

Adolescent↗
PubMed2002

Inferior capsular shift operation for multidirectional instability of the shoulder in players of contact sports.

OBJECTIVES: To assess the results of inferior capsular shift for multidirectional instability of the shoulder in athletes. METHODS: Multidirectional instability was surgically corrected in 53 shoulders in 47 athletes who engaged in contact sports. A history of major trauma was found in eight patients, the others having had minor episodes. Before surgery, all patients had complex combinations of instabilities. The surgical approach was selected according to the predominant direction of instability. RESULTS: Anterior inferior capsular shift was carried out in 37 shoulders, and anterior dislocation recurred in three. In one of these, it was anterior alone, one was anterior and inferior, and one was unstable in all three directions. After posterior inferior capsular shift in 16 shoulders, one dislocation occurred anteriorly and one posteriorly. With the anterior approach, four athletes could not return to sport. Two patients treated with the posterior approach could not return to sport. Of these six failures, five patients had had bilateral repairs. Successful repair based on the criteria of the American Shoulder and Elbow Association was achieved in 92% of anterior repairs and 81% of posterior repairs. Successful return to sport was noted in 82% of patients with anterior repairs, 75% with posterior repairs, and 17% with bilateral repairs. Overall, there were five subsequent dislocations, three in the anterior repair group (8%), and two in the posterior repair group (12%). CONCLUSIONS: Inferior capsular shift can successfully correct multidirectional instability in most players of contact sports, but the results in bilateral cases are poor.

Adolescent↗
PubMed1994

Wrist instability series: increased yield with clinical-radiologic screening criteria.

PURPOSE: To develop screening criteria for patients with wrist pain who have carpal instability. MATERIALS AND METHODS: Data were accumulated retrospectively from the cases of 535 patients with painful wrists (321 male and 214 female patients, aged 11-71 years), who underwent wrist arthrography and wrist instability series between 1979 and 1990. Four screening criteria were evaluated: abnormal carpal alignment on routine radiographs, scapholunate joint or ligament pain, reproducible painful clicking or popping, and positive capitolunate instability pattern. Patients with one or more criteria were assigned to group 1. Patients without any of the criteria were assigned to group 2. RESULTS: Group 1 comprised 142 patients (27%) and group 2 comprised 393 patients (73%). In group 1, 69 (49%) patients had abnormal wrist instability findings, and in group 2, nine (2%) had such findings. All abnormalities in group 2 were depicted on routine arthrograms. CONCLUSION: With use of these screening criteria, the majority of patients with wrist pain do not need to undergo wrist instability series and those that do can undergo a specially tailored series.

Adolescent↗
PubMed2004

Three classes of genes mutated in colorectal cancers with chromosomal instability.

Although most colorectal cancers are chromosomally unstable, the basis for this instability has not been defined. To determine whether genes shown to cause chromosomal instability in model systems were mutated in colorectal cancers, we identified their human homologues and determined their sequence in a panel of colorectal cancers. We found 19 somatic mutations in five genes representing three distinct instability pathways. Seven mutations were found in MRE11, whose product is involved in double-strand break repair. Four mutations were found among hZw10, hZwilch/FLJ10036, and hRod/KNTC, whose products bind to one another in a complex that localizes to kinetochores and controls chromosome segregation. Eight mutations were found in Ding, a previously uncharacterized gene with sequence similarity to the Saccharomyces cerevisiae Pds1, whose product is essential for proper chromosome disjunction. This analysis buttresses the evidence that chromosomal instability has a genetic basis and provides clues to the mechanistic basis of instability in cancers.

Animals↗
PubMed2005

Genotype-dependent induction of transmissible chromosomal instability by gamma-radiation and the benzene metabolite hydroquinone.

Although it is well established that ionizing radiation and benzene are epidemiologically linked to acute myeloid leukemia (AML), the underlying mechanisms are not understood. We have shown that gamma-radiation can induce a persisting genomic instability in the clonal descendants of hemopoietic stem cells manifested as a high frequency of nonclonal chromosome and chromatid aberrations. A strikingly similar instability is shown after exposure to the benzene metabolite hydroquinone. The CBA/Ca but not the C57BL/6 genotype is susceptible to the induction of instability by both ionizing radiation and hydroquinone and exposure of CBA/Ca, but not C57BL/6, mice to either agent is known to be associated with the development of AML. The results are consistent with the proposal that chromosomal instability induced by either agent may contribute to AML development by increasing the number of genetic lesions in hemopoietic cells. Genotype-dependent chromosomal instability can be induced by hydroquinone doses that are not acutely stem cell toxic and this may have important implications for current assessment of safe levels of exposure to benzene as well as for mechanistic understanding of the hemotoxic and leukemogenic effects.

Acute Disease↗
PubMed2005

Chromosomal instability in peripheral blood lymphocytes and risk of prostate cancer.

Prostate cancer is an extremely complex disease, and it is likely that chromosomal instability is involved in the genetic mechanism of tumorigenesis. Several chromosomes have been labeled as "players" in the development of prostate cancer, among them chromosome 1 and X chromosome have been reported to harbor prostate cancer susceptibility loci. However, there is little information regarding the background levels of chromosome instability in these patients. In this pilot study, we examined spontaneous chromosome instability in short-term lymphocyte cultures from 126 study subjects, 61 prostate cancer patients, and 65 healthy controls. We evaluated chromosomal instability using a fluorescence in situ hybridization assay using two probes targeting specific regions on X chromosome and chromosome 1. Our results showed a significantly higher mean level of spontaneous breaks involving the X chromosome in patients compared with controls (mean +/- SE, 2.41 +/- 0.26 and 0.62 +/- 0.08, respectively; P < 0.001). Similarly, chromosome 1 spontaneous breaks were significantly higher among cases compared with controls (mean +/- SE, 1.95 +/- 0.24 and 1.09 +/- 0.16, respectively; P < 0.001). Using the median number of breaks in the controls as the cutoff value, we observed an odds ratio (95% confidence interval) of 15.53 (5.74 - 42.03; P < 0.001) for spontaneous X chromosome breaks and 3.71 (1.60 - 8.63; P < 0.001) for chromosome 1 breaks and risk of development of prostate cancer. In conclusion, our preliminary results show that spontaneous chromosome instability could be a risk factor for prostate cancer.

Aged↗
PubMed2006

Biological characteristics in bladder cancer depend on the type of genetic instability.

PURPOSE: Malignant tumors show an inherent genetic instability that can be classified as microsatellite instability (MSI) or chromosomal instability (CIN). To elucidate the differences in biological characteristics of bladder cancer between the two types of genetic instability, the expression of the mismatch repair (MMR) proteins, Aurora-A and p53 proteins, the number of centrosomes, numerical aberrations of chromosomes and 20q13, and DNA ploidy were examined in 100 human urothelial carcinomas of the bladder. EXPERIMENTAL DESIGN: Expressions of the MLH1, MSH2, Aurora-A, and p53 proteins and the numbers of centrosomes were immunohistochemically assessed. Numerical aberrations of chromosomes 7, 9, 17, and 20q13 spots were evaluated by fluorescence in situ hybridization, and DNA ploidy was assessed by laser scanning cytometry. RESULTS: The expression levels of the MMR related-proteins decreased in 9 of 100 tumors. Tumors with low MLH1 or MSH2 expression (designated as MSI cancers) were not linked with centrosome amplification, Aurora-A overexpression, increased p53 immunoreactivity, 20q13 gain, DNA aneuploidy, and disease progression. MSI cancers showed a favorable prognosis. CIN cancers (49 cases), defined as tumors with a large intercellular variation in centromere copy numbers, were associated more frequently with centrosome amplification, Aurora-A overexpression, increased p53 immunoreactivity, and 20q13 gain than the others (51 cases). Tumors with disease progression were included in the CIN cancer group. CONCLUSIONS: The present observations suggest that there are differences in the biological characteristics of the two types of genetic instability.

Adaptor Proteins, Signal Transducing↗
PubMedDate not supplied

Medial ankle instability: an exploratory, prospective study of fifty-two cases.

BACKGROUND: Very little objective data are available regarding medial ankle instability. HYPOTHESIS: Several structures contribute to the stabilization of the medial ankle, and, in the case of injury, they are not involved in a uniform way. STUDY DESIGN: Explorative, prospective case series. METHODS: Fifty-one patients (52 ankles; males 27, females 25; age 36.4 [16 to 60] years) were surgically treated because of medial ankle instability. All clinical findings and structural changes, as found by arthroscopy and surgical exploration, were compared with the clinical diagnosis and then addressed for surgical reconstruction. RESULTS: Pain in the medial gutter was noted in all ankles (100%). Arthroscopy verified a clinically expected additional lateral instability in 40 ankles (77%). At 4.43 years (2 to 6.5 years) after surgical reconstruction, the clinical result was considered to be good/excellent in 46 cases (90%), fair in 4 cases (8%), and poor in 1 case (2%). CONCLUSION: The clinical characteristics of medial ankle instability are a feeling of giving way, pain on the medial gutter of the ankle, and a valgus and pronation deformity of the foot that can typically be actively corrected by the posterior tibial muscle. Arthroscopy was shown to be a very helpful diagnostic tool in verifying medial instability.

Adolescent↗
PubMedDate not supplied

Imaging techniques for the evaluation of glenohumeral instability.

The ability to image lesions associated with glenohumeral instability has evolved significantly over the past 2 decades. In the past, several imaging techniques ranging from conventional radiography to computerized axial arthrography and, most recently, to magnetic resonance imaging have been used to depict various labral abnormalities. In most instances, conventional radiography remains the initial imaging study for evaluating the patient with persistent shoulder pain and instability. Recently, however, magnetic resonance arthrography has been firmly established as the imaging modality of choice for demonstrating specific soft tissue abnormalities associated with glenohumeral instability. This article will review the role of various imaging modalities including conventional radiography, conventional arthrography, computerized axial arthrography, magnetic resonance imaging, and magnetic resonance arthrography. Emphasis will be placed on the role of magnetic resonance arthrography as it pertains to the lesions associated with glenohumeral instability. A thorough discussion of the appearance of normal anatomic structures, anatomic variations that mimic abnormality, and the various lesions associated with glenohumeral instability will be provided.

Arthrography↗
PubMedDate not supplied

Arthroscopic findings in patients with chronic ankle instability.

BACKGROUND: There are little objective data on structural changes of the chronically unstable ankle. Such knowledge could help with preoperative planning. HYPOTHESIS: Preoperative ankle arthroscopy provides important insights into the causes and mechanisms of ankle instability and the resulting disability. STUDY DESIGN: Case series. METHODS: From 1993 to 1999, arthroscopic examination was performed in the ankles of 148 patients with symptomatic chronic ankle instability that had lasted 6 months or more. All structural changes were recorded and compared with the clinical diagnosis. RESULTS: A rupture or elongation of the anterior talofibular ligament was noted in 86% of ankles, of the calcaneofibular ligament in 64%, and of the deltoid ligament in 40%. Cartilage damage was noted in 66% of ankles with lateral ligament injuries, whereas 98% of the ankles with deltoid ligament injuries had cartilage damage. Although lateral instability could be verified arthroscopically in 127 patients, medial instability was presumed clinically in 38 patients but was actually detected in 54 patients arthroscopically. CONCLUSION: Preoperative ankle arthroscopy revealed an essential amount of information that would otherwise have been undetected. For instance, the ligaments showed typical abnormalities corresponding to different entities of ankle instability and different intraarticular pathologic conditions.

Adolescent↗
PubMed2004

Primary repair of posterior cruciate ligament avulsion fracture: the effect of occult injury in the midsubstance on postoperative instability.

BACKGROUND: In the posterior cruciate ligament avulsion fracture, posterior instability cannot be completely restored by the anatomical reduction and fixation of an avulsed fragment. HYPOTHESIS: The occult midsubstance injury inside the posterior cruciate ligament may affect the residual posterior instability after anatomical reduction and internal fixation of the avulsed fragment. STUDY DESIGN: Prospective comparative clinical study. METHODS: Thirty-one patients were followed for a period of 2 to 8 years. Based on magnetic resonance images taken immediately after the injury, these patients were divided into 2 groups, the occult injury group (group O, 15 knees) and the uninjured group (group N, 16 knees). RESULTS: The side-to-side difference of the posterior knee instability was 3.2 mm in group O and 3.0 mm in group N. Approximately 60% of the knees examined showed mild posterior instability in both groups. There were no significant differences found between the 2 groups. CONCLUSION: The occult posterior cruciate ligament midsubstance injury does not significantly affect postoperative posterior instability of the knee. This fact did not support the hypothesis that has been commonly considered thus far. CLINICAL RELEVANCE: It is not necessary for orthopaedic surgeons to be overly apprehensive about occult midsubstance injury in the treatment of posterior cruciate ligament avulsion fracture.

Adolescent↗