Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Joint Instability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed1994

Motion and laxity of the capitellocondylar total elbow prosthesis.

The motion and laxity of the capitellocondylar unconstrained total elbow prosthesis were assessed, with use of an electromagnetic tracking device and stimulated muscle-loading, after implantation in seventeen cadaveric elbows. The axis of motion of the elbows with the capitellocondylar implants averaged 2.1 +/- 2.3 degrees more varus angulation than that of the intact elbows. This difference may be attributed to the design of the implant, as the 5-degree-valgus humeral component used in this study has a smaller valgus inclination than the articular surface of the distal aspect of the humerus. Although the maximum valgus-varus laxity of the capitellocondylar elbow prostheses was, on the average, 4.3 +/- 2.4 degrees greater than normal (with simulated muscle-loading), the data must be interpreted in light of the fact that this in vitro study did not allow for soft-tissue healing. The prosthetic components tracked well, and there were no dislocations or malarticulations provided that appropriate soft-tissue tensioning and positioning of the components had been achieved at the time of implantation. Sectioning of either the medial or the lateral collateral ligament resulted in gross instability of the joint after capitellocondylar arthroplasty. The ulnar attachment of the medial collateral ligament was found to be vulnerable to injury during the positioning of the ulnar component of this implant.

Aged↗
PubMed1987

[Post-traumatic chronic instability of the shoulder joint. Therapy and results].

If posttraumatic chronic instability of the AC-joint causes subjective complaints, this is an indication for operative therapy. In our unit 38 patients were treated at all. In most cases previous treatment had been conservative. Syndesmoplasty was done with local tissue. 33 patients were examined radiological and clinical after a minimum time of twelve months after operative treatment. The AC-joints of 25 patients were stable, in five cases there was a slight instability, in three cases there was a severe instability. Only with four patients the diminuation of mobility was of consequence.

Bone Wires↗
PubMedDate not supplied

[Muscular stabilization of the upper ankle joint in lateral instability. An experimental study].

The mechanical stabilizing effect of artificially applied muscular strength to the peroneal tendons was examined in an experimental study using cadaveric lower legs with unstable ankle joints. Therefore the anterior fibulo-talar and the fibulo-calcanear ligament was dissected and the resulting instability with examination of the anterior drawer sign and the talar tilt was measured under standardized conditions. After initial measurement under standardized conditions a muscular strength of 75 N and 150 N was applied and the resulting stability was measured again. In a second experiment an additional orthotic device was applied and the stability was measured again under applied muscular strength. The results demonstrated that stable conditions at the lateral unstable ankle joint are only achievable when a muscular strength of 75 N (ant. drawer sign) or 150 N (talar tilt) is combined with the application of an orthotic device. For clinical treatment this means that functional treatment for ankle sprains with application of an orthotic device needs additional training for improvement of the muscular strength of the peroneal muscles.

Ankle Injuries↗
PubMed1978

Radiologic determination of rotational instability of the knee joint.

A method for measuring rotational instability of the knee joint at radiography is described. Together with determination of sagittal instability the method might well serve as a simple guide in choosing the appropriate technique for surgery. It also enables an assessement of the operative results, since the method is simple and reproducible.

Biomechanical Phenomena↗
PubMed1990

[Restorative-reconstructive surgery of the bursal-ligamentous apparatus in chronic lateral instability of the knee joint].

Restorative-reconstruction operations for treatment of chronic lateral instability of knee joint have been worked out. Chronic lateral anterior varus instability is eliminated by restoration of anatomy and biomechanics of anterior cruciate ligament and restructuring of peripheral part of the bursal-ligamentous apparatus by means of creation of fibular lateral ligament and 3 derotators (1 active and 2 passive ones). This operation is indicated as well in case of grave anterolateral instability. Instability of posterior types is treated by reconstruction of precise structure and function of posterior cruciate ligament and restructuring of peripheral part of medial or lateral sections of the bursal-ligamentous apparatus (it depends upon the nature of damage) by creation of active and passive derotators.

Biomechanical Phenomena↗
PubMed1992

Traumatic disorders of the distal radioulnar joint.

Trauma can lead to isolated or associated distal radioulnar joint disorders. Instability or incongruity of the joint frequently leads to pain, weakness, and limited forearm rotation. A knowledge of the anatomy and biomechanics is helpful to understand the pathology and to formulate a treatment protocol. This article reviews the surgical options that have been proposed to correct derangements of the distal radioulnar joint resulting from trauma.

Arthroplasty↗
PubMed1995

The diagnosis and treatment of instability of the subtalar joint.

We have developed a method of measuring anterior displacement of the calcaneus on the talus in instability of the subtalar joint and have used the technique to demonstrate anterior instability in 50 patients (72 feet) showing a positive drawer sign. The angle of the posterior facet of the talus was also measured to assess the bony configuration. Our patients with subtalar joint instability could be divided into three categories. The first group had a history of trauma leading to ankle instability (26 cases), the second showed generalised joint laxity (10 cases) and the third were young females with a history of chronic stress on the foot and a poor bony block (14 cases). Satisfactory results were obtained by treating the instability with a brace or by reconstruction of the interosseous talocalcaneal ligament.

Adolescent↗
PubMed2006

Changes in lower limb kinematics, kinetics, and muscle activity in subjects with functional instability of the ankle joint during a single leg drop jump.

The purpose of this study was to identify differences in 3D kinematics, kinetics, and ankle joint muscle activity in subjects with functional instability (FI) of the ankle joint during a drop jump. Twenty-four subjects with the subjective complaint of FI of the ankle joint and 24 noninjured control subjects performed 10 single leg drop jumps onto a force-plate. Timing and magnitude of kinetic data, timing of kinematic data, and integrated EMG (IEMG) activity of the rectus femoris, peroneus longus, tibialis anterior, and soleus muscles during two 200-ms time periods either side of initial contact (IC) with the ground were analyzed and compared between groups. Subjects with FI demonstrated a significant decrease in pre-IC peroneus longus IEMG activity, which was accompanied by a change in frontal plane movement at the ankle joint during the same time period. Following IC, FI subjects were less efficient than control group subjects in reaching the closed packed position of the ankle joint. Significant differences were seen between the groups' time-averaged and peak vertical and sagittal components of ground reaction force. The altered pre-IC peroneus longus IEMG and increased inversion of the ankle joint observed in FI subjects could help to explain why subjects with FI may suffer from inversion injury to their ankle joint when subjected to an unanticipated ground contact. The kinematic and kinetic differences observed in subjects with FI may lead to repeated injury and damage to the supporting structures of the ankle joint.

Adult↗
PubMedDate not supplied

Stability and instability of the glenohumeral joint: the role of shoulder muscles.

Shoulder muscles contribute to both mobility and stability of the glenohumeral joint. To improve treatments for shoulder instability, we focused on the contribution of the shoulder muscles to glenohumeral joint stability in clinically relevant positions. Both computational and experimental models were used. A computational model of the glenohumeral joint quantified stability provided by active muscle forces in both mid-range and end-range glenohumeral joint positions. Compared with mid-range positions, the resultant joint force at end-range positions was more anteriorly directed, indicating that its contribution to glenohumeral joint stability was diminished. In end-range positions, simulated increases in rotator cuff muscle forces tended to improve stability whereas increases in deltoid or pectoralis major muscle forces tended to further decrease stability. To validate these results, a cadaveric model, simulating relevant shoulder muscles, was used to quantify glenohumeral joint stability. When infraspinatus muscle activity was decreased, compressive forces decreased. When pectoralis major muscle activity was increased, anteriorly directed forces increased. If anteriorly directed forces increase or compressive forces decrease, stability of the glenohumeral joint decreases. This cadaveric model was then used to evaluate the effect of placing the joint in the apprehension position of abduction, external rotation, and horizontal abduction. Consistent with the results of our computational model, apprehension positioning increased anteriorly directed forces. Knowledge gained from these models was then used to develop a cadaveric model of glenohumeral joint dislocation. Dislocation resulted from the mechanism of forcible apprehension positioning when the appropriate shoulder muscles were simulated and a passive pectoralis major muscle was included. Capsulolabral lesions resulted that were similar to those observed in vivo. Shoulder muscle forces are usually powerful stabilizers of the glenohumeral joint, especially in mid-range positions when the passive stabilizers are lax. However, muscle forces can contribute to instability as well. Certain muscle forces decrease glenohumeral joint stability in end-range positions. We found this to be the case with both active and passive pectoralis major forces. Improved understanding of the contribution of muscle forces not only toward stability but also toward instability will improve rehabilitation protocols for the shoulder and prove useful in the treatment of joint instability throughout the body.

Biomechanical Phenomena↗
PubMedDate not supplied

Surgical treatment of chronic lateral instability of the ankle joint. A new procedure.

Sixty patients with chronic lateral functional and mechanical instability of the ankle joint were treated with shortening and reinsertion of the lateral ankle ligaments. All patients were followed prospectively for 2 to 5 years (mean, 3 years 6 months). We found the functional results to be excellent or good in 53 patients (88%). Patients with unsatisfactory results had either generalized joint hypermobility or long-standing ligament insufficiency. Anterior talar translation (ATT) and talar tilt (TT) were measured radiologically on standardized radiographs. Patients with excellent and good functional results had better mechanical stability, both ATT and TT, than those with fair and poor functional results. A good correlation was found between clinical, functional, and radiological results. In conclusion we found that reconstruction of the ankle stability by shortening and reinsertion of the lateral ankle ligaments is a safe and simple method and is a good alternative to other more complex methods of ligament reconstruction. The method should, however, be used with great care in patients with generalized joint hypermobility or in patients with long-standing ligament insufficiency.

Adolescent↗
PubMed1980

The mechanism of acute ulnar instability of the metacarpophalangeal joint of the thumb.

Acute ulnar instability of the metacarpophalangeal joint of the thumb is divided into two distinct groups, according to the history, clinical, radiological and operative findings. In the first group it is a soft tissue injury, as a result of an unresisted abduction force to the thumb. In the second group, following a resisted abduction force, there is avulsion of a bony fragment from the base of the proximal phalanx, which is the site of common insertion of both the ulnar collateral ligament and the adductor pollicis. This is confirmed by post-mortem studies.

Adult↗
PubMed1990

[Various prerequisites for performing the Sach-Weber operation in anterior instability of the shoulder joint].

The authors present a preliminary analysis of the treatment of the patients with anterior instability of the shoulder joint who were given surgical treatment consisting in subcapital rotation osteotomy of the humerus and tendinous-capsular plasty of the anterior portion of the shoulder joint. The surgical technique and the indications for the operation are presented.

Adolescent↗
PubMed2007

Severity of scapholunate instability is related to joint anatomy and congruency.

PURPOSE: To determine whether the bony architecture of the distal radius and proximal scaphoid have a role in stabilizing the scaphoid, and to determine whether a relationship between the bony geometry measurements and the amount of wrist constraint could be determined. METHODS: Eight cadaver wrists were tested in a wrist joint motion simulator. The level of scapholunate instability after sectioning the scapholunate interosseous, radioscaphocapitate, and the scaphotrapezium ligaments was determined and related to radiographic measurements of volar tilt, lateral tilt (ulnar tilt of the radioscaphoid fossa), the depth of the radioscaphoid fossa, and 6 radii of curvature measurements of the proximal scaphoid and distal radius. The force to dorsally dislocate the scaphoid out of the radioscaphoid fossa was computed. RESULTS: The radioscaphoid fossa and scaphoid curvatures were larger in those wrists that did not show gross instability after ligamentous sectioning in the wrist simulator. Similarly, those wrists with a deeper radioscaphoid fossa and greater volar tilt were also more stable. The force required to dislocate these wrists was greater than in those wrists that showed gross carpal instability. CONCLUSIONS: This study suggests that the bony anatomy of the radius and scaphoid have a role in stabilizing the carpus after ligament injury. The effect of ligament sectioning on producing carpal instability may be moderated by the bone geometry of the radiocarpal joint. This may explain why some people may have a tear of the scapholunate interosseous ligament but not present with clinical symptoms.

Biomechanical Phenomena↗
PubMedDate not supplied

Eight-year prospective targeted ultrasound screening program for instability and at-risk hip joints in developmental dysplasia of the hip.

The use of targeted ultrasound screening for at-risk hips to reduce the rate of surgery in developmental dysplasia of the hip is unproven. A prospective trial was undertaken in an attempt to clarify this matter. This study was undertaken between May 1992 and April 2000. There were 28,676 live births. Unstable and at-risk hips were routinely targeted for ultrasound examination. One thousand eight hundred six infants underwent ultrasound examination (6.3% of the birth population). Twenty-five children (18 with dislocations, 7 with dysplasia) required surgical intervention in the form of open reduction of the hip or pelvic or femoral osteotomy (0.87 per 1,000 births for dysplasia, 0.63 per 1,000 births for dislocation). Targeted ultrasound screening does not reduce the overall rate of surgery compared with the best conventional clinical screening programs. The development of a national targeted ultrasound screening program for at-risk hips cannot be justified on a cost or result basis.

Breech Presentation↗
PubMed1996

Stress radiographs of the patellofemoral joint.

Patellar instability is usually diagnosed on the basis of the clinical presentation without radiographic confirmation. In the present report, we describe a new radiographic method to demonstrate patellar instability. Axial radiographs were made of the patellofemoral joint of ninety individuals (180 knees) and were then repeated while a medial or lateral force was applied to the patella. The applied force was kept constant with use of a specially designed instrument. The ninety individuals were divided into four groups on the basis of the clinical findings: normal, lateral instability, medial instability, and multidirectional instability. Stress radiographs differentiated the four groups and confirmed the clinical diagnosis in all patients who had unilateral symptoms. A four-millimeter increase in medial or lateral excursion of the patella excursion of the asymptomatic knee was significant (p < 0.0001). Stress radiographs offer a simple method for the measurement of force-displacement relationships in the patellofemoral joint and for the demonstration of patellofemoral instability.

Adult↗
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↗
PubMed2005

Gravity-assisted pivot-shift test for anterior cruciate ligament injury: a new procedure to detect anterolateral rotatory instability of the knee joint.

The denominated gravity-assisted pivot-shift test was introduced as a new procedure to detect anterolateral rotatory instability of the knee joint. The patient lies in the supine position or slightly rotated onto the affected side. The affected knee flexed approximately 60 degrees and the ipsilateral hip flexed, abducted and externally rotated so that the plane of the knee motion runs parallel to the floor. The examiner instructs the patient to raise the affected leg off the examining table and to extend the affected knee gradually. If the lower leg is internally rotated suddenly, with the knee subluxated at an angle of approximately 20 degrees , followed by the reduction in flexion, this test is regarded as positive. This test was investigated on 51 anterior cruciate ligament (ACL) deficient knees, being positive in 30 knees (Group P) and negative in 21 (Group N) with the positive rate of 59%. There was no significant correlation between the result of this test and the clinical features, but Group N included relatively small number of females and recurrent injuries tended to occur more frequently in Group P. Thirty-six knees received ACL reconstruction subsequently. There was no statistically significant difference between the groups in the side-to-side difference in anterior knee laxity at one year postoperatively. However, three patients with the side-to side difference of more than 3 mm belonged to Group P. Relatively low positive rate in ACL deficient knees suggests that it may not be used as a diagnostic procedure for ACL injury. It is possibly used for the prediction of high risk patients for symptomatic giving-way and/or patients with poor prognosis after ACL reconstruction.

Adolescent↗