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At least 199 records · Page 11Linked to original sources

PubMed2003

Treatment and results of sternoclavicular joint injuries.

Sternoclavicular joint injuries are uncommon. The anatomy is not familiar to most orthopaedic surgeons, and there is a high risk of both intraoperative catastrophic and postsurgical complications when performing surgery in this region. Anterior SC joint instability should primarily be treated conservatively. The patients should be informed that there is a high risk of persistent instability with nonoperative or operative care, but that the persistent instability will be well tolerated and have little functional impact in the vast majority. Therefore, operative intervention for anterior SC joint instability is mainly cosmetic in nature. Patients with posterior SC joint dislocations require an expeditious diagnosis and treatment, due to the proximity of the displaced medial clavicle to the great vessels. An early closed reduction will usually be stable. Operative stabilization must, however, be considered if the closed reduction is unsuccessful or there is persistent SC instability. SC joint stabilization should be performed with a soft tissue reconstruction, repairing both the costoclavicular ligaments and the SC capsular envelope.

Arthroplasty↗

PubMed1982

Stability of the canine shoulder joint: an in vitro analysis.

The stability of the canine shoulder joint was assessed with and without the restraining effects of selected supporting structures. Shoulder joints from medium-sized (15 to 30 kg) canine cadavers were dissected, and all soft tissues were removed except for the 4 cuff muscles (supraspinous, infraspinous, teres minor, subscapular), the biceps muscle (m biceps brachii) and the joint capsule with its associated glenohumeral ligaments. The humerus was fixed in position, and with the shoulder extended, the joint was stressed into abduction, adduction, internal rotation, and external rotation. The range of motion was measured from transverse pins placed above and below the joint. Measurements were made before and after severance of the cuff tendons and joint capsule. In selected joints, medial and lateral luxations were created. The biceps tendon was then transposed medially or laterally, respectively, to aid joint stability. Selected medial luxations were stabilized by transferring a portion of the insertion of the supraspinous tendon to a medial location. All joints were stressed as just described, and the range of motion was measured before and after tendon transfer. The joint capsule with its associated glenohumeral ligaments was an important restraint of joint motion. Lateral transfer of the biceps tendon partially corrected lateral joint instability by imposed marked rotational constraints on the joint. Medial transfer of the biceps tendon or the supraspinous tendon partially corrected medial joint instability, but did not resolve rotational abnormalities.

Animals↗

PubMed2003

Capsulo-labro-ligamentous lesions of the shoulder: evaluation with MR arthrography.

PURPOSE: The aim of the study was to analyse the accuracy of MR arthrography in the evaluation of capsulo-labro-ligamentous lesions of the shoulder in patients with glenohumeral joint instability. MATERIALS AND METHODS: From 1999 to 2001 fifty-eight patients with glenohumeral joint instability were studied by MR arthrography. Twenty-seven patients underwent surgical repair: 11 by arthroscopic and 16 by arthrotomic approach. All shoulder evaluations were performed with T1 and T2 weighted axial, coronal and sagittal oblique images, before and after intra-articular injection of gadolinium contrast. RESULTS: Forty capsulo-ligamentous lesions (including 14 capsular ruptures with extravasation of the contrast medium) were detected by MR arthrography. Fifty-two labral tears (36 of the anterior, 13 of the superior and 3 of the posterior glenoid labrum) were identified: 11 out of 52 were not recognized before gadolinium contrast injection. Five rotator cuff tears were identified, one of which was not shown in the pre-injection examination. Surgical results confirmed the MR arthrographic findings in 25/27 patients. In one case MR arthrography did not recognize a SLAP lesion; in another case it identified a tear of the capsule but not of the glenoid labrum. CONCLUSIONS: In many cases of subacute glenohumeral joint lesions with intracapsular fluid, MR may accurately evaluate capsulo-labral-ligamentous lesions. Indeed, the examination of lesions is limited by the absence of the natural contrast determined by fluid; in such cases, intra-articular injection of gadolinium contrast is necessary. MR arthrography evaluates the degree of capsulo-labro-ligamentous tears and may guide the surgical approach.

Adolescent↗

PubMed1999

Nonsurgical treatment of suprascapular nerve injury in horses: 8 cases (1988-1998).

OBJECTIVE: To determine the outcome of horses with suprascapular nerve injury treated with stall rest alone. DESIGN: Retrospective case series. ANIMALS: 8 horses. PROCEDURE: Information on signalment, history, limbs affected, severity of lameness, degree of muscle atrophy, gait abnormalities, and results of radiography and electromyography was obtained from medical records. All horses were treated with stall rest. Follow-up information on severity of lameness, gait abnormalities, degree of muscle atrophy, time between injury and resolution of gait abnormalities, and outcome was obtained during reexamination at the hospital or through telephone conversations with owners. RESULTS: In 4 horses, the injury was a result of trauma; in the other 4, the injury was suspected to be a result of trauma. All horses had pronounced instability of the shoulder joint during the weight-bearing phase. Follow-up information was available for 7 horses. Shoulder joint instability resolved in all 7 horses within 3 to 12 months (mean, 7.4 months) after the original injury. Two horses had complete return of the supraspinatus and infraspinatus muscle mass 15 and 18 months after the injury. Two horses used as broodmares before the injury and 4 of 5 horses used for riding or in race training before the injury were able to return to preinjury activities. CLINICAL IMPLICATIONS: Horses with suprascapular nerve injury treated with stall rest alone have a good prognosis for recovery of normal gait and return to performance; however, the recovery period may be prolonged.

Animals↗

PubMed1999

Neurogenic origin of articular hyperemia in early degenerative joint disease.

It has been speculated that joint instability resulting from anterior cruciate ligament (ACL) rupture could be exacerbated by changes in vasomotor activity in the remaining supporting structures. In this study, the effect of ACL transection on medial collateral ligament (MCL) basal perfusion and its responsiveness to calcitonin gene-related peptide (CGRP) and sympathetic adrenergic influences was examined. Using urethan-anesthetized rabbits, we tested the effects of CGRP and its antagonist CGRP-(8-37) by topical application of these agents to the exposed knee while sympathetic influences were tested by electrically stimulating the saphenous nerve. It was found that MCL basal perfusion was elevated in ACL-sectioned joints; however, this effect was abrogated by prior resection of the articular nerve supply. At the doses tested, the normal vasodilator response to CGRP was abolished in ACL-sectioned joints, whereas the response to CGRP-(8-37) was attenuated. Even under the influence of increased constrictor tone, MCL and capsule blood vessels still showed substantially reduced responses to exogenous CGRP administration. By contrast, nerve-mediated constrictor responses were mostly unaffected by joint instability. This study suggests that posttraumatic knee joint hyperemia is neurogenically mediated, possibly by increased secretion of CGRP.

Animals↗

PubMed2002

Vascular physiology and long-term healing of partial ligament tears.

Functional outcomes of anterior cruciate ligament (ACL) injury are generally poorer than those of medial collateral ligament (MCL) tears. Following ligament damage, all phases of ligament healing require an adequate blood supply. We hypothesized that the differences in healing properties of the ACL and MCL would reflect their vascular responses to joint injury. This paper examines the long-term changes in blood flow and vascular volume of rabbit knee ligaments after direct injury, and under conditions of chronic joint instability induced by section of the posterior cruciate ligament (PCL). Standardized injuries were surgically induced in adult rabbit knee ligaments: partial MCL transection, partial ACL transection, or complete PCL transection (joint instability). Sixteen weeks later the blood flow and vascular volume of the ACL and MCL were measured and compared to control and sham-operated animals. Direct ligament injury induced significant increases in standardized blood flow and vascular volume of both ACL and MCL after 16 weeks; however, the vascular volume of the ACL was not higher than the control levels in the MCL. We conclude that direct injury to both the anterior cruciate and MCLs induces long-term physiological responses. Joint laxity is a common sequel to PCL injury. Chronic joint laxity failed to induce adaptive vascular responses in the ACL, while the MCL shows significant amplification of blood supply. Although both MCL and ACL showed increased weight after PCL transection, the lack of a long-term vascular response in the ACL may be a major factor in its the diminished healing potential.

Animals↗

PubMed2001

Tenodesis for chronic lateral ankle instability.

The goal of lateral ankle stabilization is restoration and stability without any functional deficit. Obviously, only anatomic reconstruction can prevent deficits in range of motion. As a result, motion loss is unavoidable with tenodesis procedures. Unfortunately, no procedures are available for anatomic reconstruction of subtalar joint instability. Therefore, when there is objective evidence of subtalar joint instability, tenodesis procedures must be considered. The authors believe that stability is more important than range of motion when degenerative changes are present within the ankle joint. Tenodesis results are good for the short term (less than 5 years) but may deteriorate over time (after more than 9 years). Some residual pain is common following tenodesis procedures.

Ankle Joint↗

PubMed1994

[Colles fracture and instability of wrist joint].

We reviewed 51 cases of colles fracture patients with 3-6 years follow-up and found 20 cases had dorsal carpal subluxation (DCS) in this group. Long term results were analysed and compared between the simple Colles fracture and the Colles fracture with DCS. It was shown that the remote function of the wrist in the simple Colles fracture was much more satisfactory than in that with DCS. That indicated the DCS is a very important factor to the late results of the wrist after Colles fracture. The authors pointed out that the DCS occurs frequently in the severely displaced type caused by high energy force and in the fracture associated with scapholunate dissociation. During the close reduction of the Colles fracture associated with DCS, correction of the palmar angulation and decrease of the angle of palmar tilt should be required, as well as the neutral or light dorsal flexion fixation of the wrist after reduction.

Adult↗

PubMed2001

Comparison of autopsy, X-ray, and M.R.I. findings following a low speed impact to the shoulder.

The objectives of the study was to generate data useful to engineers improving crash test dummies and to physicians in anticipating low speed lateral impact injuries to the shoulder. Constant impact mass, distance and variable speeds were used to generate impact forces. Twelve unembalmed human cadavers were studied within 48 hours of death. Pre-test and Post-test physical, X-Ray, and Magnetic Resonance examinations were completed. X-Ray best identified bone injury, Magnetic Resonance intratendinous and intramuscular pathology and autopsy joint instability. Low speed (3.5-7.0 m/sec) impacts under these testing conditions frequently produce soft tissue and bone injuries. Sternoclavicular and acromioclavicular joint instabilities were found in 83% of the cadavers. The most frequent bone fractures were in the distal clavicle of 42% and labral or rotator cuff tears in 13% of the cadavers.

Accidents, Traffic↗

PubMed2005

Distal radius fractures: a comparison of tension band wiring versus ulnar outrigger external fixation for the management of distal radioulnar instability.

PURPOSE: To retrospectively compare the results of immobilization of the forearm in supination with the results of tension band fixation of the ulnar styloid in 35 patients with distal radius fractures, fracture of the base of the ulnar styloid, and distal radioulnar joint instability treated with external fixation. METHODS: Thirty-five patients with fractures of the distal radius, fracture of the base of the ulnar styloid, and unstable distal radioulnar joint had external fixation with adjunctive percutaneous pins and allograft bone to reduce and stabilize the distal radius fracture anatomically. Only those patients with an associated ulnar styloid base fracture displaced over 2 mm with gross distal radioulnar joint instability relative to the contralateral wrist were included in this study. Group 1 consisted of patients in whom the ulnar styloid base fracture was treated with conventional tension band wiring techniques. Group 2 patients were treated with a supplemental outrigger from the external fixator to the ulna and locked in 60 degrees of forearm supination. Groups 1 and 2 had an average follow-up period of 40 and 36 months, respectively. RESULTS: Group 2 had significantly better supination than group 1. In terms of functional outcome it was found that there was no significant difference for the Disabilities of the Arm, Shoulder, and Hand and the Gartland and Werley scores between the 2 treatment groups. There was a lower rate of complications and fewer secondary procedures were required in group 2. The incidence of distal ulna resection was 4 of the 35 patients (2 patients in each group). CONCLUSIONS: Our results indicate that patients in whom the ulnar styloid can be reduced and maintained in supination can be treated effectively with fixed supination outrigger external fixation. This method resulted in a statistically significant improvement in supination and a lower rate of distal radioulnar joint complications, and it required fewer secondary procedures.

Adult↗

PubMed1991

[Sonographic versus radiological assessment of chronic outer ligament instability of the upper ankle joint].

Chronic instability of the lateral upper ankle joint ligament is usually diagnosed by clinical and radiological examination. For the evaluation of an ultrasound method of testing lateral instability of the ankle joint we carried out a prospective study. We examined 23 adults who were actively engaged in some form of sport (21 male, 2 female, mean age 32 years) and had a preexisting lateral instability of the ankle. The instability was measured in the standard planes using Scheuba's stress apparatus with simultaneous ultrasound monitoring. The ultrasound examination was performed by positioning the 5-MHz applicator on the lateral side of the Achilles tendon, thus defining a plane from which the instability could be measured in both examination planes by observing the deviation between dorsal inferior edge of the tibia and the dorsal border of the talar roll. For the two examination planes, Spearman's rank-correlation coefficient between the radiological and ultrasound methods was 0.83 and 0.92. The sensitivity of the ultrasound method was 0.90, and the specificity was 0.85. Our study showed a good correlation between the two methods. A pathological talar tilt according to radiological criteria was also revealed by ultrasonography. Thus, all the advantages of ultrasound are now available for the evaluation of chronic lateral instability of the ankle joint.

Adult↗

PubMed1998

Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation.

The degeneration of articular cartilage as part of the clinical syndrome of osteoarthritis is one of the most common causes of pain and disability in middle-aged and older people. The strong correlation between increasing age and the prevalence of osteoarthritis, and recent evidence of important age-related changes in the function of chondrocytes, suggest that age-related changes in articular cartilage can contribute to the development and progression of osteoarthritis. Although the mechanisms responsible for osteoarthritis remain poorly understood lifelong moderate use of normal joints does not increase the risk. Thus, the degeneration of normal articular cartilage is not simply the result of aging and mechanical wear. However, high-impact and torsional loads may increase the risk of degeneration of normal joints, and individuals who have an abnormal joint anatomy, joint instability, disturbances of joint or muscle innervation, or inadequate muscle strength or endurance probably have a greater risk of degenerative joint disease. Recent work has shown the potential for the restoration of an articular surface. Currently, surgeons frequently debride joints and penetrate subchondral bone as well as perform osteotomies, with the intent of decreasing symptoms and restoring or maintaining a functional articular surface. The results of these procedures vary considerably among patients. Clinical and experimental work has shown the important influence of loading and motion on the healing of articular cartilage and joints. Experimental studies have revealed that transplantation of chondrocytes and mesenchymal stem cells; use of periosteal and perichondrial grafts, synthetic matrices, and growth factors: and other methods have the potential to stimulate the formation of a new articular surface. The long-term follow-up of small series of patients has shown that the transplantation of osteochondral autologous grafts and allografts can be effective for the treatment of focal defects of articular cartilage in selected patients. Thus far, none of these methods has been shown to predictably restore a durable articular surface to an osteoarthritic joint, and it is unlikely that any one of them will be uniformly successful. Rather, the available clinical and experimental evidence indicates that future optimum methods for the restoration of articular surfaces will begin with a detailed analysis of the structural and functional abnormalities of the involved joint and the patient's expectations for future use of the joint. On the basis of this analysis, the surgeon will develop a treatment plan that potentially combines correction of mechanical abnormalities (including malalignment, instability, and intra-articular causes of mechanical dysfunction), debridement that may or may not include hunted penetration of subchondral bone, and applications of growth factors of implants that may consist of a synthetic matrix that incorporates cells or growth factors or use of transplants followed by a postoperative course of controlled loading and motion.

Adult↗

PubMed2006

Measuring knee joint laxity: a review of applicable models and the need for new approaches to minimize variability.

Knee joint laxity can result from soft tissue injury, such as a ligament tear, or from genetic factors such as joint hypermobility syndrome and various forms of Ehlers-Danlos Syndrome. The location of a subject's passive knee laxity along a continuous spectrum is dependent on the mechanical properties of the existing structures, and the increased motion that often follows joint injury. At a threshold along the spectrum, a patient will be at risk for joint instability and further injury to joint structures. Links between instability and laxity may be better understood if laxity can be reliably and accurately quantified. Current measures of laxity have not been compared to a 'gold standard' in all cases, and when they have, were found to overestimate the laxity values. This is attributed to soft tissue deformation. Consequently, a noninvasive measure of laxity with improved accuracy and repeatability would be useful clinically and in the research sector. In this review, current clinical measures of laxity are critiqued, criteria for a measure of laxity are identified, and three theoretical models of knee laxity are outlined. These include contact, lumped parameter, and finite element models, with emphasis on applicability, strengths, and limitations of each. The long term goal is to develop a model and method able to differentiate subjects along a spectrum of laxity, and understand the functional implications of altered joint integrity. This would allow careful scrutiny of clinical interventions aimed at improving joint health and provide a valuable research tool to study joint injury, healing, and degeneration.

Anterior Cruciate Ligament↗

PubMed2007

Glenohumeral kinematics following total shoulder arthroplasty: a finite element investigation.

The osseous geometry of the glenohumeral joint is naturally nonconforming and minimally constrained, and the joint's stability is maintained by action of the rotator cuff muscles. Damage to these muscles is often associated with joint degeneration, and a variety of glenoid prostheses have been developed to impart varying degrees of stability postoperatively. The issues of conformity and constraint within the artificial shoulder have been addressed through in vivo and in vitro studies, although few computational models have been presented. The current investigation presents the results of three-dimensional finite element analyses of the total shoulder joint and the effects of design parameters upon glenohumeral interaction. Conformity was shown not to influence the loads required to destabilize the joint, although it was the principal factor determining the magnitude of humeral head translation. Constraint was found to correlate linearly with the forces required to dislocate the humeral head, with higher constraint leading to slightly greater humeral migration at the point of joint instability. The model predicts that patients with a dysfunctional supraspinatus would experience frequent eccentric loading of the glenoid, especially in the superior direction, which would likely lead to increased fixation stresses, and hence, a greater chance of loosening. For candidates with an intact rotator cuff, the models developed in this study predict that angular constraints of at least 14 degrees and 6.5 degrees in the superoinferior and anteroposterior axes are required to provide stable unloaded abduction of the humerus, with larger constraints of 18 degrees and 10 degrees necessitated by a dysfunctional supraspinatus. The tools developed during this study can be used to determine the capacity for different implant designs to provide resistance to excessive glenohumeral translations and reduce the potential for instability of the joint, allowing surgeons to optimize postoperative functional gains on a patient by patient basis.

Arthroplasty, Replacement↗

PubMed2003

Musculotendinous anomalies in musician and nonmusician hands.

Musculoskeletal abnormalities of musicians' hands and upper extremities are well-recognized and potentially career-threatening problems. Of the many types of potentiality problematic musculoskeletal disorders that could be assessed, this study focused on joint instability and musculotendinous anomalies. For this study, the hands of 92 music students were compared with the hands of 64 nonmusician control subjects. Flexor anomalies were observed much more frequently than extensor musculotendinous anomalies; clinical evidence of the Linburg-Comstock anomaly was noted for 60 to 70 percent of subjects in both groups. Further analysis of the Linburg-Comstock anomaly demonstrated that the sites of pain among test-positive subjects were variable, test positivity was more frequent in the left hand and among string players, and test positivity tended to decrease from the radial side to the ulnar side of the hand. There were only two definite extensor musculotendinous anomalies (1.3 percent), and both involved a subluxating extensor mechanism affecting the little fingers. Forty-three percent of all subjects exhibited a degree of instability affecting the joints of their hands.

Adult↗

PubMed2005

Use of hinged transarticular external fixation for adjunctive joint stabilization in dogs and cats: 14 cases (1999-2003).

OBJECTIVES: To describe placement of hinged transarticular external fixation (HTEF) frames and evaluate their ability to protect the primary repair of unstable joints while allowing joint mobility in dogs and cats. DESIGN: Retrospective study. ANIMALS: 8 cats and 6 dogs. PROCEDURE: HTEF frames were composed of metal or epoxy connecting rods and a hinge. Measurements of range of motion of affected and contralateral joints and radiographs were made after fixator application and removal. RESULTS: 9 animals (4 cats and 5 dogs) had tarsal and 5 (4 cats and 1 dog) had stifle joint injuries. Treatment duration ranged from 45 to 100 days (median, 57 days). Ranges of motion in affected stifle and tarsal joints were 57% and 72% of control while HTEF was in place and 79% and 84% of control after frame removal. Complications were encountered in 3 cats and 2 dogs and included breakage of pins and connecting rods, hinge loosening, and failure at the hinge-epoxy interface. CONCLUSIONS AND CLINICAL RELEVANCE: HTEF in animals with traumatic joint instability provided adjunctive joint stabilization during healing and protection of the primary repair and maintained joint motion during healing, resulting in early weight bearing of the affected limb.

Animals↗

PubMed1999

Radiographic measurement of craniocaudal instability in stifle joints of clinically normal dogs and dogs with injury of a cranial cruciate ligament.

OBJECTIVE: To determine craniocaudal laxity of the stifle joint of dogs when joints were positioned in tibial compression or neutral position. SAMPLE POPULATION: 19 normal stifle joints in 10 clinically normal dogs, 29 stifle joints with varying injury to the cranial cruciate ligament (10 complete ruptures alone, 10 complete ruptures with concomitant damage to the medial meniscus, 6 partial ruptures alone, and 3 partial ruptures with concomitant meniscal tearing), and 19 unaffected contralateral stifle joints in those 29 dogs. PROCEDURE: Relative displacement of bony landmarks was measured on paired lateral radiographs (neutral and tibial compression positions). Two measuring techniques were customized for use in dogs. RESULTS: The first technique failed to distinguish results in normal stifle joints from those in stifle joints with partial deficiency of cranial cruciate ligaments. Significant differences were found for joints with complete rupture, compared with stifle joints in clinically normal dogs. The second technique detected differences between normal stifle joints and injured joints with partial or complete rupture of the cranial cruciate ligament. Significant differences were not detected between joints with partial versus complete rupture. Adjusting data to account for size of dog did not improve results. CONCLUSIONS AND CLINICAL RELEVANCE: A wide range in measurements of laxity was found for stifle joints with intact cranial cruciate ligaments. Differences in degree of damage to the ligament and medial meniscus cannot be deduced from the amount of relative displacement measured on radiographs. Pathologic changes to the cranial cruciate ligament will not necessarily induce detectable changes in laxity of stifle joints in dogs.

Animals↗

PubMed1997

Superficial and deep defects in dyschondroplastic and degenerated pig articular cartilage.

Normal and pathological (osteochondrotic and osteoarthrotic) pig articular cartilages from medial humeral and femoral condyles were studied by scanning electron microscopy. The pathological cartilages showed primitive osteochondrotic lesions with progressive aspects according to the severity of the pathology (flaking, fibrillation and cracks) and other superficial changes (micro-undulation, micro-fissurations, clefts) that appeared to be a consequence of the action of intense mechanical stresses such as shearing forces, compressive deformation, friction of the articular surfaces. The observation of deep lesions such as cracks and fractures at or near the interface between cartilage and calcified zone, frequently observed both at medial condyle and at intercondylar crista of the humerus, often evolving in cartilagineous flaps, were related to excessive tangential and shear forces induced by an abnormal articular topography resulting in joint instability. This pathological joint dynamic could be also worsened by an anomalous leg conformation (cross-legs) and/or by an increased occurrence of environmental micro- and macrotrauma (impact loading). Also in this case, the frequency and severity of the lesions can be increased if the deep layer is affected by osteo-chondrotic lesions. The results stress the pathogenetic importance of mechanical load in initiating and worsening the articular lesions in pigs; they also suggest that the resulting alterations can be influenced by a pre-existing different maturity or pathological condition of the cartilage.

Animals↗