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Monopolar radiofrequency energy effects on joint capsular tissue: potential treatment for joint instability. An in vivo mechanical, morphological, and biochemical study using an ovine model.

The purpose of this study was to evaluate the thermal effect of monopolar radiofrequency energy, a potential treatment means for joint instability, on the mechanical, morphologic, and biochemical properties of joint capsular tissue in an in vivo ovine model. The energy was applied arthroscopically to the synovial surface of the femoropatellar joint capsule of 24 sheep. The sheep were sacrificed at 0, 2, 6, and 12 weeks after surgery (6 per group). Monopolar radiofrequency energy initially caused a significant decrease in tissue stiffness and an increase in tissue relaxation properties, followed by gradual improvement in the tissue's mechanical properties by 6 weeks after surgery. Microscopic examination illustrated that radiofrequency energy initially caused collagen hyalinization and cell necrosis, followed by active tissue repair. Biochemical analysis revealed that treated collagen was significantly more trypsin-susceptibile than untreated collagen at 0 and 2 weeks after surgery, indicating early collagen denaturation. This study demonstrated that this treatment initially caused a significantly deleterious effect on the mechanical properties of the joint capsule, which was associated with partial denaturation of joint capsular tissue. This was followed by gradual improvement of the mechanical, morphologic, and biochemical properties of the tissue over time.

Animals↗

Chronic recurrent anterior sternoclavicular joint instability: results of surgical management.

Chronic anterior sternoclavicular joint (SCJ) instability may cause pain and persistent functional limitation in active patients. Although SCJ reconstruction and medial clavicular resection have been advocated in these situations, the results of surgical treatment are not well characterized. The purpose of this investigation was to determine the functional outcome of surgical treatment in adolescent and young adult patients with chronic recurrent anterior SCJ instability. Fifteen patients with chronic recurrent anterior SCJ instability refractory to nonoperative therapy who underwent joint reconstruction or medial clavicular resection were evaluated for pain and function using the American Shoulder and Elbow Surgeons (ASES) Standard Shoulder Assessment Form and the Simple Shoulder Test (SST). At average follow-up of 55 months, the mean ASES score was 85 and the mean SST score was 10.9. Sixty percent of patients reported stable, pain-free joints, although 87% (n = 13) reported some limitations of athletic or recreational activity. There were no surgical complications, and no patient underwent subsequent revision procedures. Although subsequent activity modification is often required, surgical treatment of chronic anterior SCJ instability in adolescents and young adults can provide near-complete pain relief and return of shoulder and upper extremity function.

Adolescent↗

[Surgical treatment of chronic upper ankle joint instability in childhood].

The Department of Traumatology of the Hanover Medical School treated 347 patients having chronic instability or second stage rupture of the fibular ligament system, by surgery, during 1971 through 1986. Children were represented by one-seventh of the total number of patients only (13%; n = 44); however, in children the preoperative and intraoperative findings are different from normal findings and must be treated surgically in a special way. Whereas in adults old osseous/osteochondral ligament tears are apt to be rare (16% of the cases), they can be seen in children in almost every second case (18 of 44). Surgical approach requires a step-by-step procedure to achieve maximum stability and minimum functional loss. First Choice: Direct reconstruction of the ligament in case of ligaments which are present but have not healed correctly from a biomechanical point of view (e.g. pseudoarthroticosseous ligament tear) or in case of second-stage rupture (n = 20). Second Choice: Double periosteal flap plasty in case of necessary replacement of only one ligament (n = 13). Third Choice: Tenodesis of m. peroneus brevis using only half of the tendon chip while sparing the epiphysis if the condition persists for many years, or if ligaments cannot be reconstructed or replaced intraoperatively or if there is a combined instability of the ankle joint and the talo-calcaneonavicular joint (n = 11). In almost 90% of the cases very good to good results were obtained after five years, assessed according to a 100-point schema.

Adolescent↗

Familial joint instability syndrome.

We describe a family in which many persons have generalized joint laxity frequently complicated by dislocation of major joints. The condition is an autosomal dominant trait, with high penetrance. The disorder observed in this family and in others from the literature appears to be a specific syndrome that can be distinguished from other familial forms of joint laxity such as simple familial joint laxity and the Ehlers-Danlos syndromes. It has been designated the familial joint instability syndrome.

Adolescent↗

Glenohumeral joint instability in normal adolescents. Incidence and significance.

One hundred and fifty asymptomatic shoulders in 75 schoolchildren were studied. The shoulders were tested for instability and a hyperextensometer was used to assess joint laxity. Signs of instability were found in 57% of the shoulders in boys and 48% in girls; the commonest sign was a positive posterior drawer test which was found in 63 shoulders. A positive sulcus sign was found in 17 shoulders and 17 subjects had signs of multidirectional instability. General joint laxity was not a feature of subjects whose shoulders had positive instability signs.

Adolescent↗

Split biceps femoris tendon reconstruction for proximal tibiofibular joint instability.

Recurrent instability of the proximal tibiofibular joint is an infrequently diagnosed abnormality. We present a new technique for reconstructing the joint using a split biceps femoris tendon passed through a bone tunnel in both the proximal tibial metaphysis and fibular head. The case report is also presented. The procedure offers an anatomic reconstruction and firm stabilization. It allows normal motion of the proximal tibiofibular joint and preserves the normal mechanics of the ankle. This procedure is an excellent alternative to resection of the fibular head, transarticular arthrodesis, or pseudoarthrosis focus at the fibular head.

Adult↗

Hip joint instability after the neonatal period. II. The acetabular growth potential.

In 26 girls with idiopathic hip joint instability, diagnosed after the neonatal period, the acetabular angle is measured before and after treatment. A mathematical analysis of the acetabular growth potential in these hip joints and normal ones is presented. During treatment the monthly reduction of the acetabular angle is greater than in normal hip joints. The age limit for sole treatment in immobilisation without operative procedures is discussed.

Acetabulum↗

Patellar tendon rupture and marked joint instability after total knee arthroplasty.

BACKGROUND: Patellar tendon rupture is a rare complication of total knee arthroplasty (TKA). Multiple repair methods have been described in the literature. METHODS: A 66-year-old woman suffered a patellar tendon re-rupture and marked joint instability within 6 months after revision TKA. She underwent re-revision TKA and extensor mechanism reconstruction with femoral quadriceps tendon and augmentation by a Leeds-Keio ligament. RESULT: It was fairly difficult to acquire a satisfactory range of motion as well as gain in knee extension capacity by eliminating the extension lag. CONCLUSION: Patellar tendon ruptures after TKA should be repaired as soon as they are recognized.

Aged↗

Prevention of congenital dislocation of the hip. The Swedish experience of neonatal treatment of hip joint instability.

The extensive work on early diagnosis and treatment of CDH (in the broad sense of this term) in Sweden has formed the basis of our present organization of prevention of hip dislocation. Practically all children are born in hospital, at present about 93,000 per year (1980). Routine examination of the hip joints has been included in the check-ups of newborns since the beginning of the 1950's. The centralization of obstetrics, especially during the last decade, has facilitated the organization of these examinations by paediatric consultants in all obstetric departments. All cases of hip joint instability are recorded, and during the last few years the frequency has been about 12 per thousand, probably with some over-diagnosis due to registration of uncertain cases. All definite cases of hip instability have been treated immediately at the orthopaedic departments. A study of a series of untreated newborns with transient instability has shown that the majority, but not all, will develop normal hip joints without treatment. This has been one reason for the recommendation to treat all unequivocal cases of hip instability. The present organization of examination and treatment is described. Detailed and practical instructions for the examination and treatment are given. Follow-ups of children treated for hip instability in the neonatal period are reported. It has been found that in practically all these patients anatomically normal hip joints are achieved by means of correct and carefully followed up treatment. The findings in 65 patients with neonatal hip instability in whom the treatment was unsuccessful or inadequate have underlined the importance of a strict treatment schedule, experienced doctors and detailed information to the parents. The effect of diagnosis and treatment of hip instability neonatally on the frequency of late-diagnosed cases of CDH was studied by recording all late-diagnosed cases at all orthopaedic departments. It was clear from the latter study that instability of the hip in newborns represents "preluxation" and that the treatment of this can prevent later dislocation. Dislocation of the hip joint in newborn infants is very unusual. Nowadays it is rare even after the neonatal period--in recent years only 12% of the late-diagnosed CDH cases between 1 and 6 months of age at diagnosis. However, the total number of late-diagnosed cases in the whole country has not decreased by more than 50% compared with the period prior to the introduction of hip examination of newborns.(ABSTRACT TRUNCATED AT 400 WORDS)

Child↗

[Forms of post-traumatic knee joint instability].

The authors have proposed an addition to the clinical classification of posttraumatic instability of the knee joint, based upon the complex clinico-physiologic evaluation of functional state of a joint as a single system. According to the degree of expression of morpho-functional changes there have been singled out compensated, subcompensated and decompensated forms of posttraumatic instability. Singling out of the given forms orients the physician in selection of tactics of carrying out of pre- and postoperative periods, helps a surgeon to solve the problem of optimal plan of operative treatment.

Diagnosis, Differential↗

Hip joint instability after the neonatal period. Diagnosis and treatment of 20 consecutive cases.

A consecutive series of 20 children (21 hips) with idiopathic hip joint instability, diagnosed after the neonatal period, is presented. The diagnosis was confirmed by hip joint arthrography. In all the children, 1.5-21 months old at the time of diagnosis, closed reduction could be achieved. They were treated in plaster directly or after treatment of contractures in the adductor muscles of the hip joint. Stability was rapidly attained during plaster treatment. The results of the treatment in plaster were checked by a second arthrography in two thirds of the cases, and all cases have been clinically and radiologically evaluated 1-4.5 years after diagnosis. All of the children developed clinically stable hips and they walk normally. In two hips signs of avascular necrosis of the femoral head were found and in three hips (two children) the skeletal development was markedly delayed. In 81 per cent (17/21 hips) the prognosis was considered good; it is uncertain in the remaining four hips. The appropriate period of fixation in plaster related to the age of the child is discussed.

Casts, Surgical↗

The effect of joint instability on latency and recruitment order of the shoulder muscles.

Several shoulder dysfunctions are generally characterized as Shoulder Impingement Syndrome (SIS). Specifically, glenohumeral instability (GI) has been viewed as a primary cause of SIS in young individuals, mainly in overhead athletics. Past studies have associated GI with modifications in latency, recruitment order and/or EMG activity. However, it is not clear if pain and/or joint instability can account for these observed changes. The aim of this investigation was to analyze the effect of glenohumeral instability on the latencies and recruitment order of the superficial muscles of the glenohumeral and scapulothoracic joints in swimmers without pain symptom. Eight individuals with and eight without history of Shoulder Impingement Syndrome performed bilateral and simultaneous shoulder elevations at three different distances. The shoulder kinematics and EMG activities of glenohumeral and scapulothoracic muscles were registered. Results showed that subjects of both groups performed the task with similar latencies and recruitment order of the muscle activities. We conclude that shoulder instability does not necessarily affect the latencies and recruitment order of the shoulder muscles during the elevation of the shoulder in the scapular plane. Pain and other factors may be involved in the kinematics and electromyographic alterations demonstrated in other experiments.

Adult↗

[Gonarthrosis following persisting knee joint instability (author's transl)].

It is frequently assumed that persisting instability of the knee joint leads to gonarthrosis. We have reviewed recent and primary radiograms of 32 patients with old knee trauma resulting in prolonged capsular and ligamentous instability in order to study the eventual development of secondary gonarthrosis. Our results were as follows: All primarily intact joints developed gonarthrosis after an average of 46 months of permanent instability. Primarily existing gonarthrosis increased with exception of 3 cases. The tendency to develop an arthrosis seems to be proportional to the duration of instability; the type of instability apparently has no influence on the development of an instability gonarthrosis. Operative procedures having been performed prior to final stabilysing surgery obviously do not cause the development of secondary gonarthrosis. The persisting instability of the knee joint after combined discontinuation of capsule and ligaments therefore may be regarded as a prearthrotic factor.

Adult↗

A model of dynamic sacro-iliac joint instability from malrecruitment of gluteus maximus and biceps femoris muscles resulting in low back pain.

The objective of this work is to propose a biomechanical model of sacro-iliac joint dysfunction as a cause of low back pain. Sacro-iliac joint is known to be a source of low back pain. We also know that it is a very stable joint with little mobility. Surrounding lower limb and back muscles contribute a major part of this stability. Gait analysis studies have revealed an orderly sequence of muscle activation when we walk - that contributes to efficient stabilisation of the joint and effective weight transfer to the lower limb. Gluteus maximus fibres-lying almost perpendicular to the joint surfaces are ideally oriented for this purpose. Biceps femoris is another important muscle that can also influence joint stability by its proximal attachment to sacrotuberous ligament. Altered pattern of muscle recruitment has been observed in patients with low back pain. But we do not know the exact cause-effect relationship. Because of its position as a key linkage in transmission of weight from the upper limbs to the lower, poor joint stability could have major consequences on weight bearing. It is proposed that sacro-iliac joint dysfunction can result from malrecruitment of gluteus maximus motor units during weight bearing. This results in compensatory biceps over activation. The resulting soft tissue strain and joint instability may manifest itself in low back pain. If our hypothesis holds true, it may have positive implications for patients with sacro-iliac joint dysfunction - who could be offered a definite diagnosis and targeted physiotherapy. It may be possible to identify patients early in a primary care setting and offer direct physio referral. They could benefit from exercises to improve strengthening and recruitment of the affected muscles.

Buttocks↗

Osteoarthritis development in novel experimental mouse models induced by knee joint instability.

OBJECTIVE: Although osteoarthritis (OA) is induced by accumulated mechanical stress to joints, little is known about the underlying molecular mechanism. To apply approaches from mouse genomics, this study created experimental mouse OA models by producing instability in the knee joints. METHODS: The models were of four types: severe, moderate, mild, and medial, depending on the severity and direction of instability imposed by combinations of ligament transection and menisectomy. OA development was evaluated by X-ray and histology by Safranin-O staining, and quantified using our original gradings. Expressions of type II, IX and X collagens and matrix metalloproteinase (MMP)-2, -3, -9 and -13 were further examined by immunohistochemistry and in situ hybridization (ISH). RESULTS: The severe, moderate and mild models exhibited OA development in the posterior tibial cartilage. The severe model showed cartilage destruction at 2 weeks and osteophyte formation at 4-8 weeks after surgery; however, the mild model showed only a partial cartilage destruction at 8 weeks. The grading confirmed that the OA disorders progressed depending on the severity of joint instability. In the medial model, the OA development in the medial tibial cartilage was similar to that in the posterior cartilage of the mild model. Among the collagens and MMPs, type X collagen and MMP-13 were markedly induced and colocalized in the early stage OA cartilage. CONCLUSION: We established four types of mouse models exhibiting various speeds of OA progression. By applying a mouse genomics approach to the models, molecular backgrounds in various stages of OA development can be clarified.

Animals↗