Arthroscopy: possibilities and limitations in the diagnosis and therapy of meniscus lesions

The menisci consist of fibrocartilage and are an important supporting structure of the knee joint. They are poorly vascularized and have to withstand a high mechanical strain and load; therefore, lesions are common, especially on the medial side. Meniscal lesions are among the most frequent surgical procedures in orthopedic surgery. Meniscal lesions are diagnosed by a careful clinical examination in 80% of all cases in spite of modern imaging techniques such as magnetic resonance imaging (MRI). In the last 15 years, arthroscopic meniscectomy has become the 'golden standard' of therapy. Arthroscopy provides a powerful tool to precisely locate and classify the type of meniscus injury and to perform arthroscopic meniscectomy at the same time. This means less morbidity, reduced hospitalization time and earlier return to work and hence reduced costs. The endoscopic technique allows to exactly remove the damaged parts of the meniscus with precision instruments (partial meniscectomy). Former open techniques only allowed the complete removal of the meniscus. The arthroscopic techniques used nowadays allow a preservation of the functionally important edge of the meniscus, which is responsible for the stability and the biomechanics of the knee joint and can thus prevent an early onset of arthrosis. In rare cases of peripheral meniscal tears in young patients, arthroscopic refixation is an advantageous treatment option. Partial arthroscopic meniscectomy and arthroscopic meniscus refixation are challenging therapeutic procedures that require a trained and experienced orthopedic surgeon. Today diagnostic arthroscopy is more and more abandoned in favour of noninvasive and reliable MRI techniques. MRI is also useful in cases of previous knee surgery and clinically unclear findings, but should not be used on a routine basis. In differential diagnosis, the orthopedic surgeon always has to evaluate the MRI findings as to their impact. Today, arthroscopic knee surgery is a reliable, technically sophisticated and standardized technique to treat meniscal damages of all patients. There is a relatively low rate of complications, provided that the indication for the procedure is critically applied and restricted to patients with sufficient clinical and MRI findings.     

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.     

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.     

Clinical and sonographic meniscus diagnosis

Clinical examination still plays an important role in diagnosing meniscal tears. The types of sensitive nerves in the knee joint are responsible for nonspecific pain, which is often correlated with too little specificity in meniscal tests. Ultrasound examination of meniscal structures of the knee joint has been debated extensively in recent years. Criticism of this noninvasive technique was due to small patient groups, improper technical and inaccurate manual standards. Since 1988 ultrasound of the tibial meniscus has become a standard technique in our Department of Orthopaedic Surgery with defined criteria of the intersecting plane and evaluation of ultrasound images. A prospective follow-up study during 6/1988 and 5/1993 including 1186 ultrasound examinations before arthroscopy, was performed. The sensitivity for ultrasound of the lateral meniscus was 58% and for the medial meniscus 83%. Specificity with 98% for the lateral and 90% for the medial meniscus was good. Sonographic detection of meniscal tears depends on the shape and location of meniscal tears. This has been shown by experimental studies in cadavers. A follow-up study including 113 knee joints was performed to prove the value of clinical and ultrasound examination in relation to arthroscopy. The sensitivity of sonography for medial meniscus was 81% and 40% for the lateral meniscus. Although the sensitivity of the clinical examination was 81% (medial) and 47% (lateral), the low specificity of 70% for meniscus tears indicated that it was because of false-positive clinical evaluation of meniscal disorders. In young patients with reflectory muscle spasm and those with acute trauma of the knee joint, clinical examination of the meniscal structures showed poor results. In these cases, too, ultrasound examination showed advantages. Ultrasound of the knee joint meniscus is noninvasive, reproducible and low cost. In cases of uncertain clinical results, ultrasound offers a good opportunity to visualize meniscal disorders.     

Magnetic shaping of columns of liquid sodium

The meniscus of a cylindrical column of liquid sodium in mineral oil was shaped under an electromagnetic field. The electromagnetic field was generated by an alternating current flowing through a coil surrounding the liquid metal column. The equilibrium shape of the meniscus, under the influence of electromagnetic field, was experimentally measured and compared with the predicted results from the mathematical model. The experimental technique used to measure the meniscus shape of the liquid metal column and the development of the mathematical model are presented. The validity of the mathematical model to predict the meniscus shapes is also discussed.     

Heparin immobilized on proteins usable for arterial prosthesis coating: growth inhibition of smooth-muscle cells

Fifty-one patients with meniscal repair using the outside-in technique were reassessed with second-look arthroscopic procedures (N = 15), arthrographic examination (N = 41), magnetic resonance imaging (N = 36), or a combination of these techniques. Forty-one medial and 10 lateral menisci were repaired. The average clinical follow-up was 15 months (range, 3 to 80). Forty-five of 51 patients had tears that were located in or extended into the posterior horn of the medial or lateral meniscus. Complete healing occurred in 23 menisci (45%), partial healing was observed in 16 (15 medial, 1 lateral) (32%), and no healing occurred in 12 (24%). Remarkably, in all 15 patients who had tears extending from the posterior to the middle third of the medial meniscus that were partially healed, it was always the posterior third that had not fully healed. This finding is statistically significant. In addition, the middle third of these menisci had not fully healed in five patients. No healing occurred in the two patients with tears in the posterior third of the medial meniscus. Poor healing with the outside-in technique was observed in patients with tears into the posterior horn of the medial meniscus. For tears in the middle and anterior portion of the medial meniscus, as well as all lateral meniscus tears, the outside-in technique is our current method of choice.     

Knee injury in children

The diagnosis approach after knee injury in children must be carefully taken care of the growth plates but it is necessary to emphasize the frequency of the ligament and intra-articular lesions, and on the other hand to consider their benign reputation. Clinical and conventional radiologic examination give in most of the cases the correct diagnosis. For the others an examination under general anesthesia ++ is necessary to distinguish the ligament and the growth plate lesions. MRI must not replace the arthroscopy which is necessary for an haemarthrosis with a stable knee or a little isolated anterior instability. The non-surgical treatment is indicated for benign sprain and non-displaced or mid-displaced fractures if the reduction is perfect and stable. All the other lesions need a surgical treatment which must be the most conservative as possible, especially for the meniscus, because their integrity is a guarantee for the quality of the long term result.     

A new technique for arthroscopic resection of a bucket handle tear

The authors present a previously undescribed technique for excision of a bucket handle tear. The technique uses a Caspari suture punch to pass a suture through the meniscus and use the suture as a tool to maneuver the meniscus so that its posterior horn attachment can be cut. The technique is noteworthy in that it eliminates the need for establishing an additional portal.     

Arthroscopic treatment of cysts of the lateral meniscus

We have treated 69 patients with 72 cystic lateral menisci by arthroscopic surgery. Meniscal tears were observed in all cases, and 69 of these had a horizontal cleavage component. Three types of tear were identified and may be progressive. Treatment was by arthroscopic resection of the meniscal tear, and decompression of the cyst through the substance of the meniscus. After a mean follow-up of 34 months the results were good or excellent in 64 knees (89%) and there were few complications. We recommend this technique as the treatment of choice for cysts of the lateral meniscus.     

Parathyroid lesions localized by radionuclide subtraction and ultrasound

Radionuclide subtraction technique and gray-scale echography were used to localize parathyroid lesions in 6 patients with primary hyperparathyroidism. In 3 cases, surgery verified the scintigraphic findings. All lesions weighed less than 1 g, with the smallest weighing 350 mg. These procedures provide complementary information in preoperative localization of hyperfunctioning parathyroid tissue.     

Comparison of dynamic contrast-enhanced gradient-echo and spin-echo sequences in MR of head and neck neoplasms

PURPOSE: To investigate the utility of dynamic contrast-enhanced gradient-echo MR imaging of head and neck lesions and to compare this technique with the commonly used spin-echo contrast-enhanced fat-saturation technique. METHODS: Twenty-two patients with a total of 23 head and neck neoplasms underwent dynamic gradient-echo and spin-echo MR imaging studies. The spin-echo and dynamic gradient-echo images were compared in each case by consensus of three observers for differences in tumor conspicuity and delineation of margins, particularly with regard to invasion of adjacent structures. When possible, pathologic and/or surgical confirmation of tumor extent was obtained. Relative contrast was also calculated to determine objectively the degree of tumor enhancement with respect to background mucosa. RESULTS: The dynamic gradient-echo images showed better or equal delineation of the tumor margins by subjective observation in all but two cases. Temporally different enhancement patterns were noted for lesions, background mucosa, and adjacent reaction and edema. The dynamic gradient-echo technique provided better relative contrast than the spin-echo technique in 17 (77%) of 22 lesions. CONCLUSION: Dynamic gradient-echo MR imaging is superior to conventional contrast-enhanced spin-echo imaging in delineating the margins and extent of tumor. This technique provided observers with added confidence in their interpretations and suffered from fewer technical limitations.     

Prognosis and treatment of burns

The experience in therapeutic digestive endoscopy is presented using injection technique with adrenalin-polidocanol of gastrointestinal hemorrhage lesions. One hundred and twenty nine patients were treated endoscopically; the medium age was 60 years; in almost 80% of the cases, peptic ulcer disease were found. The effectiveness was 91.4% when one session procedure was used and in some cases two sessions were applied, giving a final total arrest of hemorrhage of 95.3%. The total mortality still remain high (16.3%) even without bleeding, due to coexisting poor general conditions of the patients. The technique of endoscopic injection is reviewed and the final results of our work are presented.     

Magnetic resonance imaging in 80 cases of orbital tumors

Magnetic resonance imaging (MRI) is a new medical imaging technique which has been used in evaluating ocular and orbital diseases in recent years. Owing to the high resolution of soft tissues and lesions, it is superior to ultrasound and computed tomography in the localization and characterization of an orbital tumor in diagnosis. In this paper, we analysed 80 cases of MR images of orbital tumors by which all the lesions were detected. Benign or malignant disorders were recognized in 59 cases and complete tumors with accurate localization were shown in 79 cases. The principles of MRI, signal intensity of various tumors and the indications of MRI were discussed.     

Cyst of the medial meniscus: observation of two cases

The authors report two cases of cyst of the medial meniscus. In both cases imaging diagnostics, CT scan, or MRI allowed us to reveal the characteristic horizontal meniscal lesion that would be the primary cause of cystic degeneration of the meniscus. The two cases were treated by selective resection of the meniscal lesion and arthroscopic decompression of the cyst.     

Influence of the status of the contralateral carotid artery on the outcome of carotid surgery

This is a preliminary report of four cases of meniscal displaced tears: two bucket handle medial meniscus tears, one complex tear in the avascular zone or lateral meniscus, and one longitudinal full-thickness tear on the lateral meniscus. These tears were treated by applying hi-frequency current stimulation to the tissues and obtaining total meniscal visual healing on a second arthroscopic view after 6 weeks.     

Minimally invasive knee joint surgery

The treatment of knee joint injuries has seen a marked development. Arthroscopy is standard for diagnostic purposes, for meniscus resection and meniscus refixation. Anterior cruciate ligament reconstruction may be performed mini-invasive by arthroscopic or mini-open technique with comparable result. Drill guide systems and fixation techniques allow for precise and stable graft placement. Posterior cruciate ligament surgery is presently undergoing a similar process of optimisation as ACL surgery has some years ago. The surgical trauma of intraarticular fracture reconstruction was also reduced significantly. Retrograde nailing, percutaneous plating and specific exposures to distal femur and proximal tibia fractures have been established. Percutaneous osteosynthesis controlled by arthroscopy or fluoroscopy is widely used for B-fractures of the tibial plateau. Injectable bone mineral cement adds to reduced trauma of surgical treatment of these fractures. Mini-invasive knee surgery will develop rapidly in the coming years.     

肺硬化性血管瘤的CT影像学特点

Objective: The aim of the study was to analyze the CT morphology features of pulmonary sclerosing hemangiomas (PSHs) and improve the diagnosis ability of this disease. Methods: The 18 cases of pulmonary sclerosing hemangioma (PSH) confirmed by operation and histopathology from August 2002 to May 2009 were collected, including 17 females and 2 males, aged from 19 to 60 years old, with an average age of 43 years. All the cases underwent plain CT scan, among them,16 cases received enhanced CT scan. Results: The 18 cases had isolated mass. Mean long-axis diameter of these lesions was (2.7 ± 1.3) cm (range, 1.9-4.2 cm). Of all cases, 5 cases (27.8%) were round in shape, 9 cases (50%) were oval, 4 cases (22.2%) were lobulated, and 14 cases (77.8%) were smooth margin. The air meniscus sign was in 2 cases (11.1%), and the halo sign in 3 cases (16.7%). Two cases (11.1%) contained small nodular calcification, the remaining 16 cases (70%) were homogeneous density, the CT density of the masses ranged from 24-47 HU, and the mean value was 35 HU. Sixteen cases received enhanced scan, the welt vessel sign was in 8 cases (44.4%),1 case showed less enhancement, 5 cases showed marked homogeneous enhancement and 10 cases showed intense and patchy heterogeneous enhanced. The CT density of the enhancing masses ranged from 60-110 HU, the mean value was 35 HU, and the net enhancement value was 14-80 HU, the mean value was 55 HU. Conclusion: PSH should be considered in middle-aged female whose CT found that single round or oval pulmonary nodules, with smooth margin, or associated with the air meniscus sign, the halo sign, or the marked enhancement.     

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.     

软接触电磁结晶器内三维弯月面形状数值模拟

建立了软接触电磁结晶器内交变磁场和三维弯月面形状的耦合模型,在用实验结果验证的基础上,模拟了方坯连铸结晶器三维弯月面形状,研究了弯月面形状的不均匀特性,讨论了感应线圈与初始钢液面之间的相对位置、电流强度和电源频率等因素对弯月面形状的影响。结果表明：当初始钢液面位于感应线圈中心位置附近时,电磁力对金属的约束成形作用最强;电流强度比电源频率能更明显地改变弯月面形状,但提高电源不仅能适当增加弯月面高度,还有利于弯月面的稳定,在实际应用中应采用20kHz以上的电源频率。     

A Study for Initial Solidification of Sn-Pb Alloy during Continuous Casting: Part I. The Development of the Technique

The importance of initial solidification of molten steel in the mold has been widely acknowledged. However, very few studies have been effectively developed because of the high transient nature of thermodynamics and fluid flow in the upper mold. Based on the recently developed mold simulator technology, a novel technique has been successfully developed to study the initial solidification behavior of Sn-Pb alloy, which gives rise to the clear understanding of the interrelationship between complex meniscus heat transfer, casting surface oscillation marks (OM), and mold hot-surface responding temperatures. The results suggested that the variations of the responding temperatures and heat flux at meniscus may be associated with the movement of mold in/out of the bath, the infiltration of silicon oil, and the latent heat release due to the solidification of meniscus during negative strip time (NST). The presence of positive peaks in the derivative of the heat flux are corresponding to each of the OM during NST, which suggests the significant increase of heat flux during the formation of OM. These could be explained as the meniscus is deformed and gets closer to the coldest mold at the beginning of NST, such that the liquid meniscus that gives rise to the increase of heat flux would be solidified. With the enhancement of oil infiltration from the mid-NST to end-NST, the thermal resistance between the solidified meniscus and mold decreases; therefore, the shell continues to grow, and the resulting heat-transfer and mold temperatures also continue to increase.