肌电生物反馈在半月板切除术后股四头肌功能恢复中的应用

将２５名半月板切除术后的患者，随机分成肌电生物反馈治疗线及对照组，指导患者进行股四头肌等长训练，训练前后均进行股四头肌的肌电水平、患肢负重及股四头肌徒手肌力测定。结果表明：训练后股四头肌的肌电增加增度肌电生物反馈组明显大于对照组（Ｐ＜０．０１）；在患肢负重能力方面，两组对比，反馈治疗组明显成于对照组（Ｐ＜０．０１）；训练前后的肌力测定显示；反馈治疗组训练后股四头肌肌力达到Ｖ组的百分率是６４．２％，     

Magnetic Resonance Imaging of the Postoperative Meniscus

Imaging of the postoperative meniscus is a challenge. Nevertheless, magnetic resonance imaging (MRI) of the symptomatic knee after meniscal surgery is a valuable diagnostic study of both the menisci and the entire joint. At present, symptomatic patients who have had partial meniscectomy of less than 25% may be evaluated by MRI. For those with partial meniscectomy of greater than 25% or after meniscal repair, direct or indirect magnetic resonance arthrography (MRA) should be considered. Currently, the decision of whether to perform direct (intra-articular) versus indirect (intravenous) MRA must be reviewed on a case-by-case basis considering both the patient's ability to tolerate intra-articular injection and whether a significant effusion already exists, which will imbue the tear with synovial fluid (making intra-articular injection of less importance). In such cases of significant effusion, indirect MRA would be preferred. If MRI or MRA is contraindicated, computed tomography arthrography seems a promising alternative. For a patient who has undergone meniscal allograft transplantation, MRI seems adequate for detecting meniscocapsular healing, allograft extrusion, and allograft tear. Future improvements in MRI sequencing may obviate the need for invasive modalities.     

Evaluating meniscus allograft transplant using a cost-effectiveness threshold analysis

Background

It is unknown if meniscal allograft transplant (MAT) delays progression of osteoarthritis (OA). Cost-effectiveness threshold analysis can demonstrate the necessary delay in OA progression required by MAT to be considered cost-effective compared to non-operative management. The purpose of this study is to identify the efficacy MAT requires in delaying progression to OA in previously meniscectomized knees in order to be considered cost-effective compared to non-operative treatment. A secondary goal is to demonstrate the influence of age and BMI on the required efficacy of MAT for cost-effectiveness.

关节镜下膝关节半月板手术

1993年4月～1994年4月,在膝关节镜下部分半月板切除78例次,全切除6例次,修正术12例次,边缘缝合3例次,计99例次(90例).经过1年～1年半随诊,优良率达92%,取得较好效果.认为膝关节镜下半月板切除术,是治疗半月板损伤较好的手术方法.     

Nine cases of osteonecrosis in elderly patients following arthroscopic meniscectomy

We report nine cases of osteonecrosis of the knee after arthroscopic meniscectomy between 1992 and 1996. In five women and four men aged between 58 and 82 years (mean 69 years), magnetic resonance imaging (MRI) demonstrated a meniscal tear for which arthroscopic meniscectomy was performed. MRI was done between 3 days and 72 weeks after the onset of symptoms. Signs of osteonecrosis were not present on the initial MRI scan. Postoperatively, all patients experienced persistent knee pain and joint effusion. A repeat MRI scan 6–48 weeks after meniscectomy confirmed the diagnosis of osteonecrosis. In eight patients osteonecrosis was located on the medial, in one patient on the lateral femoral condyle. Our report supports the results of recent studies which have related osteonecrosis to arthroscopic meniscectomy. Further studies need to be undertaken to determine the aetiology of the osteonecrosis related to this procedure in the elderly. Until the results of these studies are available, we recommend considering carefully before performing arthroscopic procedures in the elderly. Received: 3 April 1997 Accepted: 25 September 1997     

Early changes in material properties of rabbit articular cartilage after meniscectomy

We have correlated early material and biochemical changes in articular cartilage in a surgical model for cartilage degeneration. Medial meniscectomy was performed on the left knee of 17 adult, female New Zealand white rabbits. The equilibrium Young's modulus of cartilage was assessed by an indentation test in situ at defined sites on the medial and lateral tibial plateaus of the operated and control knees; the cartilage was then excised and analyzed biochemically. Focal changes were consistently observed in the medial surface of the operated knee. The equilibrium modulus and the glycosaminoglycan content fell rapidly, reaching a minimum by 2 weeks after surgery; the lateral tibial surface was essentially unaffected. Six months after surgery, the glycosaminoglycan content had returned to normal and the modulus to near normal. Independent measurements on cored plugs from the medial surface 2 weeks after surgery revealed a significant decrease in both the dynamic stiffness and the streaming potential in the operated knee compared with the control. The findings suggest that normal ambulatory loads in vivo will deform the affected medial cartilage much more than normal. It remains to be seen if altered mechanical stresses are solely responsible for initiating and sustaining matrix remodeling by the chondrocytes.     

Proteoglycan Breakdown of Meniscal Explants Following Dynamic Compression Using a Novel Bioreactor

Motivated by our interest in examining meniscal mechanotransduction processes, we report on the validation of a new tissue engineering bioreactor. This paper describes the design and performance capabilities of a tissue engineering bioreactor for cyclic compression of meniscal explants. We showed that the system maintains a tissue culture environment equivalent to that provided by conventional incubators and that its strain output was uniform and reproducible. The system incorporates a linear actuator and load cell aligned together in a frame that is contained within an incubator and allows for large loads and small displacements. A plunger with six Teflon-filled Delrin compression rods is attached to the actuator compressing up to six tissue explants simultaneously and with even pressure. The bioreactor system was used to study proteoglycan (PG) breakdown in porcine meniscal explants following various input loading tests (0–20% strain, 0–0.1 MPa). The greatest PG breakdown was measured following 20% compressive strain. These strain and stress levels have been shown to correspond to partial meniscectomy. Thus, these data suggest that removing 30–60% of meniscal tissue will result in the breakdown of meniscal tissue proteoglycans.     

Experimental Measurement of Tibiofemoral Contact Area in a Meniscectomized Ovine Model Using a Resistive Pressure Measuring Sensor

Animal models are necessary for the development and analysis of surgical techniques in meniscal surgery because they are the only means of preclinically determining the influence of biological factors such as healing processes and joint remodeling. Furthermore, little is known about the biomechanical effect of meniscectomy in sheep. The aim of the study was thus to investigate the efficacy of using a resistive pressure measuring sensor to quantify the effect of chronic meniscectomy in an ovine model. Twelve sheep were divided into two groups (n = 6): a sham operated control group (A), and a medially meniscectomized group (B). After six months, lower limb specimens were loaded with a joint-compressive force of 500 N during which the pressure measuring sensor was positioned underneath the meniscus to determine contact area, mean and peak contact pressure. A significant reduction in contact area of about 55% was observed in the meniscectomized knees compared to the controls. Peak contact pressure of the meniscectomized knees significantly increased an average of 260.4% compared to the control knees. Based on the results of this study, we conclude that the resistive pressure measuring sensors provide a means to experimentally measure tibiofemoral contact mechanics even in this relatively small (compared to human) animal model.     

Lateral discoid meniscus: Treatment and results

Forty-six patients (47 knees) who had symptomatic discoid lateral menisci were operated on between August 1981 and May 1989. The patients were categorized according to Watanabe's classifications: complete (80.8%), incomplete (10.6%), and Wrisberg type (8.5%). The treatment of the discoid meniscus is based on total or partial meniscectomy, achieved by the percutaneous or arthrometric technique. Of the 47 knees, 30 underwent a follow-up evaluation. Using Ikeuchi's knee scale, 27 cases (90%) had either excellent or good ratings, and 3 (10%) received fair ratings. There were no poor outcomes. The results in the knees treated by partial meniscectomy were better than those in the knees treated with total meniscectomy.