Inheritance of antibody specificity: the IgM anti-lipopolysaccharide response in mice

Double contrast arthrography of the knee is the method of choice for visualization of the menisci, while the single positive contrast technique is the preferred method for evaluation of the cruciate ligaments. A technique is described which combines the advantages of these two methods. Following radiography of the menisci, an essentially single positive contrast study of the cruciate ligaments is obtained by positioning the patient in the lateral recumbent position with the knee flexed to about 90degree. The positive contrast medium in this position fills the joint cavity beyond its mid-point and surrounds the cruciate ligaments. Tomographic studies of the midline of the knee joint, made in this position with a polytome unit, demonstrate the cruciate ligaments to best advantage.     

Arthrography of the knee. II. Isolated and combined lesions

The findings in 1 349 abnormal cases out of 2 836 arhtrographies of the knee have been evaluated statistically. Isolated and combined lesions of menisci, medial collateral and cruciate ligaments have been compared. Type and degree of the individual lesion change with increased complexity of combined injuries. A sequential grading for some lesions has been established. A dominant direction of rupture was found differing in themedial and lateral meniscus. Vertical ruptures anf ruptures of the posterior part of the medial meniscus were positively correlated to more complex injuries.     

Patella fractures associated with injuries of the knee ligament

Concurrent fractures of the patella and knee ligament ruptures are rare. From September 1985 to November 1989, 112 fractures of the patella were treated operatively at the Department of Traumatology at Celje General Hospital. In six patients (5%), associated badly injured ligaments of the knee joint were noted. During the operation, osteosynthesis of the patella was performed after the injured ligaments had been reconstructed. It is essential to examine the knee ligaments under general anesthesia before performing osteosynthesis of the patella. We have found no reports on this uncommon injury in the literature.     

Magnetic resonance imaging of knee injuries in children

The appearances of knee injuries on MR imaging are less well documented in children than adults. Some patterns of injury are shared by both groups of patients, e. g. meniscal damage. The frequency of specific injuries may differ, e. g. anterior cruciate ligament (ACL) tear. Congenital abnormality, coexistent pathology and previous treatment of the knee appear to be associated with meniscal problems. Discoid menisci are seen most frequently in children and have unique features on MR scans. Cruciate ligament tears are difficult to diagnose in the smallest children. The ACL may not be identified due to its small size. Normal bone marrow signal may be confused with marrow infiltration or bone microfracture. Radiographically occult fractures around the knee appear to be strongly associated with ligamentous injury as in adult patients. Osteochondral fractures, osteochondral lesions and articular cartilage damage are revealed on MR scans, but their long-term effects are uncertain. It is possible to diagnose a range of knee injuries on MR scans in children. The biggest diagnostic challenge is in pre-school children.     

Magnetic resonance imaging of the musculoskeletal system. Part 4. The knee

Since its introduction to musculoskeletal imaging in the early 1980s, magnetic resonance imaging has proven to be an excellent technique for evaluating patients with knee problems. Studies have shown it to be accurate in the identification of abnormalities of the menisci, ligaments, patellofemoral joints, and other soft tissue and osseous structures in the knee. The main advantages of magnetic resonance imaging are its noninvasive nature and its high accuracy and negative predictive value in evaluating the menisci and anterior cruciate ligament. Magnetic resonance imaging has been shown to be useful in the detection and diagnosis of various traumatic and nontraumatic knee abnormalities. It has also proved useful in the diagnosis of occult or unsuspected bone lesions. Magnetic resonance imaging can therefore help in the selection of those patients who need therapeutic arthroscopy. There is evidence that magnetic resonance imaging of the knee is a cost effective screening technique when used in conjunction with the clinical findings in patients who are candidates for arthroscopy. Magnetic resonance imaging of the knee is still a relatively expensive modality.     

Synovial cyst of the cruciate ligament. Findings with magnetic resonance in 8 symptomatic cases

Intraarticular ganglion cysts are uncommon findings: only 30 cases have been reported since the first paper by Caan in 1924 and they were all associated with cruciate ligaments. Many different cystic or pseudocystic lesions are found in articular knee conditions: the most common cystic lesions are popliteal cysts (Baker's cysts), followed by synovial pseudocysts of the posterior cruciate ligament, meniscal cysts and, finally, ganglion cysts of the cruciate ligaments. In our series of 1600 knee MR exams carried out in our MR department since June, 1994, we have found 8 ganglion cysts of the cruciate ligaments. MR studies are always performed on a dedicated 0.2-T permanent magnet (Artoscan, Esaote Biomedica, Genoa, Italy). Five patients were operated on with arthroscopy. The ganglion cysts affected the anterior cruciate ligaments in 4 cases and the posterior cruciate ligaments in 4 cases. The symptoms were mainly pain radiating to the medial side and worsening in forced flexion or extension. The diagnostic suspicion was meniscal tears in 4 patients, chondral lesions in 3 and a loose intraarticular body in one patient. The shape and structure of ganglion cysts in the cruciate ligaments are clearly depicted with MRI. The ganglion cysts in the anterior cruciate ligaments are usually spindle-shaped and within the ligament, while those in the posterior cruciate ligaments have a well-defined outline, with multilocular appearance, and they are usually localized along the ligament, most often on the dorsal aspect. MR signal studies show intermediate signal intensity on SE T1-weighted images and markedly increased signal intensity on SE T2-weighted images. These typical patterns may change depending on lesion content, for instance in the presence of hemoglobin due to an associated angioma. The origin of ganglion cysts in the cruciate ligaments is still unknown, even though many theories have been suggested, including a synovial herniation in ligament fibers, the ectopic inclusion of synovial tissue, a posttraumatic connectival degeneration and, finally, the proliferation of totipotent mesenchymal cells. From a histologic point of view, "synovial ganglion" is a much better definition than "synovial ganglion cyst", because the typical wall of real synovial cysts is missing. The MR patterns are typical of the morphological features described and of the presence of high protein fluid content.     

Traumatic knee luxation

This report is based on two case stories. Traumatic knee dislocation is a rare but serious event. There is extensive damage to the ligaments of the knee, but the vascular lesions, with an incidence of approximately 29% are of primary concern. Signs of ischaemia indicate arteriography or exploration, and if the vascular lesion is repaired within eight hours, the majority can avoid amputation. Complicating fractures, ligament lesions and nerve lesions have secondary priority to arterial lesions. A combination of surgical ligament-repair/reconstruction and intensive rehabilitation seems the most promising.     

Lesions of the popliteus system and their significance for the stability of the knee joint

INTRODUCTION: St?ubli postulated a clinical significance of lesions to the popliteus system because of a 95% incidence in acute and 85.7% in chronic ruptures of the cruciate ligaments. The sparse clinical literature on this topic favours conservative or operative treatment as well. OBJECTIVE OF THE STUDY: What is the significance of isolated lesions of the popliteus tendon on translational stability of the knee joint? MATERIAL AND METHODS: The popliteus tendon was severed in six sheep. One year postop. the knee joints were evaluated by means of x-ray, biomechanical testing, computed tomography osteoabsorptiometry (CTOAM) and micromorphology. RESULTS: There were no pathological findings on x-ray. The simulation of the trauma situation ex vivo showed no instability whereas increased translation and progressive loosening of secondary stabilizers was found after one year (posterior and total aptranslation, compliance index p < 0.05). The position of the density maxima of the subchondral mineralization are about the same on the operated and the non-operated knee joint. All tendons healed macroscopically, but micromorphology exhibited a persisting increase of cross-sectional areas, a low differentiated ultrastructure of the tendon and an increased cellularity (p < 0.01). CONCLUSIONS: Experimental: 1. intraarticular, extrasynovial tendons heal spontaneously even within the synovial environment; 2. healing is defective even one year postop.; 3. the postulate of the significance of the popliteus system for the stability of the knee is proven. Clinical: 1. (isolated) lesions of the popliteus go undetected with clinical and instrumented examination; 2. conservative treatment eventually results in increased posterior translational instability; 3. this will increase strain and load on the menisci and ACL- reconstructions.     

Diagnostic and therapeutic standard in meniscus lesions--results of a survey]

With a survey among surgeons and orthopaedic surgeons in German speaking countries the presently applied diagnostic and therapeutic schemes of meniscus lesions were investigated. In 322 questionnaires altogether 43.958 meniscus lesions were reported. In over 90% arthroscopy serves as diagnostic and therapeutic tool. Two thirds of the surgeons suture a longitudinal tear of the outer zone of the meniscus, all the other meniscus lesions were foremost treated by partial resection. The postoperative treatment after meniscus surgery is very inconsistent. Altogether less preserving meniscus operations were performed than it would be possible according to the literature. On one hand new therapy regimens are acknowledged by clinical practice with considerable delay, on the other hand the importance of menisci for the integrity of the knee-joint necessitates a further improvement of reconstructive techniques for preservation of the menisci.     

Meniscal lesions

The menisci of the knee play an important role in joint congruence, stability and absorption. They thus contribute to cartilage preservation. This is why current treatment of meniscal lesions is based on the notion of maximum preservation of the menisci: meniscectomy as partial as possible, but also whenever possible, meniscal repair (meniscal suture), or abstention from surgery (the lesion left in place). The type of therapy depends on the one hand on the type of meniscal lesion (traumatic or degenerative), but also on the context (age, state of the cartilage, and especially state of the ligaments). In case of associated rupture of the anterior cruciate ligament, treatment of the ligament lesion (ACL reconstruction) usually takes precedence over treatment of the meniscal lesion; the latter, whenever possible, is preserved (suture or abstention). In the case of meniscal lesion on an otherwise intact knee, the usual approach is very partial arthroscopic meniscectomy. Arthroscopy has shortened the immediate postsurgical effect, but long-term results still show a certain percentage of narrowing joint's space, in particular on the lateral meniscus.     

Evaluation of the healing process in fractures using early and delayed bone scanning

Fifty-two fracture sites were evaluated by bone scintigraphy after acquiring similar views of the lesions at 4 and 24 h following technetium-99m methylene diphosphonate administration. After calculating 24/4 h radio-uptake ratio (RUR) and using 1.15 as the critical point of separation, fresh healing lesions could be separated from old healed fractures persisting as 'hot spots' with a sensitivity of 100% and specificity of 82%. The 24/4 h RUR technique is a new approach in measuring the osteoblastic activity at the lesion site. The technique appears to have clinical significance in the detection and follow up of the healing status of occult fractures where radiological procedures are of limited value.     

Effect of femoral condyle configuration on disability after an anterior cruciate ligament rupture. 100 patients followed for 5 years

We measured the configuration of the femoral condyles on lateral radiographs in 100 consecutive, prospectively-studied patients with a complete rupture of the anterior cruciate ligament, with or without associated lesions of the menisci and collateral ligaments. The patients had mainly low-to-moderate activity demands, and in all the patients the cruciate tear was primarily treated non-operatively. A quotient was calculated from the measurements of sagittal depth and axial height in order to describe the geometry of the femoral condyles. Measurements were reproducible with an intra- and interobserver coefficient of correlation of 0.89-0.98. At follow-up, after 5 (3-6) years, 16 patients had developed disability leading to reconstructive surgery. The remaining 84 patients did not have any major functional limitations, but some had reduced their activity level. Individual variations in the articular geometry were found with a more spherical shape of the femoral condyles in the patients where non-operative treatment had failed. Our findings indicate that articular geometry is of importance for function after an anterior ligament lesion.     

The effects of an artificial meniscus substitute in a knee joint with a resected anterior cruciate ligament. An experimental study in rabbits

A Dacron meniscus prosthesis was substituted for the medial meniscus in an anterior cruciate ligament (ACL) resected rabbit knee. At three months, the joints were evaluated biomechanically, with gross and histologic inspection. In a paired comparison with the contralateral knee, differences between ACL resection with intact, incised, or resected medial menisci were evaluated. Knees with intact menisci and ligaments served as controls. Because of cartilage destruction, soft-tissue hypertrophy, and increased anterior laxity, joint stiffness was less than normal in all ACL-resected knees. Ingrowth and stable fixation, especially of the posterior horns of the prostheses and the incised menisci, were rare. Almost all normal menisci had ruptured in the same area. Anterior cruciate ligament resection led to severe osteoarthrosis in both compartments, regardless of initial meniscal treatment. Knees with prostheses had the same incidence and severity of osteoarthrosis as knees with meniscus resection. Anterior cruciate ligament resection alone induced excessive osteoarthrosis and synovitis and diminished the effects of different meniscal treatments three months earlier.     

Gas chromatographic-mass spectrometric investigations on the formation of phenolic and aromatic hydrocarbons in food (author''s transl)

Experience from arthroscopy in 224 patients with knee complaints is reported. The common method for arthroscopy is compared with a new modification developed during the study. The new method includes introduction of a 5 mm arthroscope through the patellar tendon at the level of the joint line and the use of hooks to test the menisci and the ligaments. The experience from this method shows that it gives an expanded field of vision and that technical failures are less frequent. No complications occurred. It is stated that arthroscopy is of great value in the diagnosis of knee injuries. However, a high diagnostic accuracy can only be reached by an experienced operator using a strictly standardized method.     

Intraarticular lesions in distal fractures of the radius in young adults. A descriptive arthroscopic study in 50 patients

We examined the frequency of associated chondral and ligament lesions in distal fractures of the radius in young adults (men 20-60 years, women 20-50 years). Fifty initially displaced fractures were examined arthroscopically. Chondral lesions were found in 16 patients (32%). All patients but one were found to have a ligamentous injury in the wrist. No major instability was found. The most frequent ligament tear was the triangular fibrocartilage complex in 39 cases (78%), with a statistical correlation to ulnar styloid fractures. The scapholunate ligament was partially or totally torn in 27 cases (54%). No correlation was found between specific fracture type and pattern of ligament injury. Chondral and ligamentous lesions were frequent and may explain poor outcomes after seemingly well-healed distal fractures of the radius. The ligament lesions should also be kept in mind when early mobilization of the distal fracture of the radius is considered.     

Treatment of deep cartilage defects of the patella with periosteal transplantation

Injuries of the nasoethmoid-orbital (NEO) region are associated with midfacial fractures or fractures of the frontobase in over 90% of all cases. In up to 70% fractures of the skull base run through the roof of the ethmoidal bone or the lamina cribrosa. There are different surgical approaches for the treatment of these complex fractures. Between 1990 and 1997 50 patients with midfacial fractures in association with NEO fractures were treated in the Klinik für Mund-, Kiefer- und Gesichtschirurgie, Kantonsspital Luzern, Switzerland. Of these, 25 had suffered midfacial fractures combined with fractures of the nasoethmoid-orbital and frontobasal region and were treated via a transcranial approach. The other 25 patients with midfacial and NEO fractures without involvement of the frontobasis were managed by subcranial incisions. A total of 47 patients were followed up for up to 4 years. The results were reevaluated retrospectively. There was no case of secondary liquorrhea, intracranial or ethmoidal infection. Our therapeutic concept of transcranial and subcranial management of NEO fractures in combination with frontobasal and midfacial fractures is demonstrated.     

Keratinocyte growth stimulation by granulocyte-macrophage colony-stimulating factor (GM-CSF)

A comprehensive review of ultrasonography of the knee is presented and includes the choice of equipment and best patient positioning as well as a review of the normal anatomy and major disorders involving the knee, menisci and ligaments.     

Double-contrast arthrography in meniscal lesions and patellar chondropathy

The technique of double-contrast arthrography is discussed in this paper. The serial exposures included a special exposure of the retropatellar region in order to detect patellar chondropathy. Various types of meniscal rupture and degeneration are discussed with special reference to combinations of these lesions and to lesions of both menisci in the same knee joint. The aetiology and radiological features of patellar chondropathy are discussed in detail. Patellar chondropathy was diagnosed in 19% of patients without meniscal lesions, 23% of patients with medial and 35% of those with lateral meniscal lesions, as well as in 73% of post-meniscectomy cases. Comparison of arthrographic with arthroscopic results revealed a positive correlation in 74% of cases.     

Diagnosis and therapy of the rupture of both cruciate ligaments, the medial collateral ligament and abscission of both menisci in a ram. A case report

This report describes the case history of a 1.5-year-old ram admitted to the Clinic for Food Animals and Horses, University of Berne, Switzerland, because of an acute severe lameness of the left rear limb. Clinical and radiographic examination revealed disruption of the stifle joint with rupture of both cruciate ligaments, the medial collateral ligament, and disruption of both menisci from their attachments. The ruptured ligaments were replaced by synthetic ligament prostheses. Long-term examination at 12 months after implantation revealed slight instability of the stifle joint, caused by degeneration of the medial meniscus, and signs of arthrosis deformans. The new formed periarticular connective tissue contributed to the stability of the stifle joint, so that a good functional result was achieved. Necropsy findings at 14 months after implantation confirmed that the synthetic ligament prostheses were intact and the medial meniscus was detached from its insertion and incorporated into the joint capsule. At microscopic examination of the synthetic band prosthesis, ingrowth of collagen and fibrous tissue was evident.     

Carpal instability

Traumatic carpal instability implies that the normal relationships of the radiocarpal and mid carpal joint are distorted either statically or during dynamic stress. Normal kinematics of the carpus are dysfunctional. The causes of carpal instability are dissociation of the intercarpal ligaments on either side of the lunate, a so-called scapholunate dissociation or a luno-triquetral dissociation. Carpal instability nondissociative is generally due to a laxity or attenuation of the intrinsic ligaments of the carpus and are associated with deformity of the distal radius. Ulnar translation of the carpus on the distal radioulnar articular surfaces occurs with shear stretching of the origins of the radiocarpal ligaments. The radial styloid attenuation of the ligaments may result in abnormal motions of the carpal bones going from ulnar to radial deviation at which time a catch-up click may occur. Carpal instabilities are usually associated with malalignment of the lunate with respect to the longitudinal axes of the radius and capitate and tends to assume an extended position with scaphoid fractures or injuries to the scapholunate ligament, a palmar flexed position with injuries to the luno-triquetral area or the ulnar capsule.