Factors for the presence of anteromedial rotatory instability of the knee

Anteromedial rotatory instability (AMRI) of the knee joint was investigated with an instrument newly designed to simulate the manual AMRI test and to quantify its magnitude. Thirty healthy subjects, 20 patients with anterior cruciate ligament (ACL) injury, and 10 with both ACL and medial collateral ligament (MCL) injuries were examined. Using the instrument, 100N of anterior force was applied to the proximal part of the tibia with the foot in neutral rotation, 30° of internal rotation, and 30° of external rotation, and the magnitude of anterior displacement was recorded. The measurement was carried out at 20° and 90° of flexion. A significant increase in anterior laxity was observed in all three rotation positions in the injured patients. However, the magnitude of laxity in external rotation was less than that in neutral rotation in the ACL injured patients, whereas it was the greatest in external rotation in ACL + MCL injured patients. Thus, we conclude that an injury involving both the ACL and MCL causes AMRI.     

Clinical Results of Technique for Double Bundle Anterior Cruciate Ligament Reconstruction Using Hybrid Femoral Fixation and Retroscrew

Background

Anatomic anterior cruciate ligament (ACL) reconstruction has been presented as a means to more accurately restore the native anatomy of this ligament. This article describes a new method that uses a double bundle to perform ACL reconstruction and to evaluate the clinical outcome.

Methods

Grafts are tibialis anterior tendon allograft for anteromedial bundle (AMB) and hamstring tendon autograft without detachment of the tibial insertion for posterolateral bundle (PLB). This technique creates 2 tunnels in both the femur and tibia. Femoral fixation was done by hybrid fixation using Endobutton and Rigidfix for AMB and by biointerference screw for PLB. Tibial fixations are done by Retroscrew for AMB and by native insertion of hamstring tendon for PLB. Both bundles are independently and differently tensioned. We performed ACL reconstruction in 63 patients using our new technique. Among them, 47 participated in this study. The patients were followed up with clinical examination, Lysholm scales and International Knee Documentation Committee (IKDC) scoring system and radiological examination with a minimum 12 month follow-up duration.

Results

Significant improvement was seen on Lachman test and pivot-shift test between preoperative and last follow-up. Only one of participants had flexion contracture about 5 degrees at last follow-up. In anterior drawer test by KT-1000, authors found improvement from average 8.3 mm (range, 4 to 18 mm) preoperatively to average 1.4 mm (range, 0 to 6 mm) at last follow-up. Average Lysholm score of all patients was 72.7 ± 8.8 (range, 54 to 79) preoperatively and significant improvement was seen, score was 92.2 ± 5.3 (range, 74 to 97; p < 0.05) at last follow-up. Also IKDC score was normal in 35 cases, near normal in 11 cases, abnormal in 1 case at last follow-up.

Conclusions

Our new double bundle ACL reconstruction technique used hybrid fixation and Retroscrew had favorable outcomes.     

膝关节前交叉韧带前内束和后外束股骨止点位置的解剖研究

目的探讨膝关节前交叉韧带（ACL）前内束及后外束股骨止点的解剖位置,找到确定ACL前内束和后外束股骨止点的简单可行的方法,为双束重建ACL手术中的股骨骨道定位提供理论支持。方法解剖18个新鲜膝关节标本（25～45岁）的股骨端前内束和后外束的足迹,以标定前内束和后外束股骨止点中心点的位置。在屈膝90°位,测量ACL前内束及后外束股骨止点中心点距股骨髁间窝外侧壁前方、后方和下方软骨缘的距离。再对测量数据进行评估和对比。结果 ACL后外束股骨止点中心点距离股骨前方软骨缘（8.55±1.33）mm,距离股骨后方软骨缘（8.65±1.54）mm,二者间无统计学差异（t=-0.191,P〉0.05）;而ACL后外束股骨止点中心点距离股骨下方软骨缘（5.11±0.79）mm。ACL前内束股骨止点中心点距离股骨前方软骨缘（14.95±2.06）mm,距离股骨后方软骨缘（6.08±0.88）mm,二者间有统计学差异（t=16.633,P〈0.01）;而ACL前内束股骨止点中心点距离股骨下方软骨缘（9.10±1.55）mm。结论膝关节屈膝90°时,ACL后外束的股骨止点中心点位于股骨髁间窝外侧壁距离下方软骨缘5mm的高度,并处在与前方和后方软骨缘几乎等距的位置。而ACL前内束的股骨止点中心点位于股骨髁间窝外侧壁距离下方软骨缘9mm的高度,并处在前后连线大约后1/3的位置。在ACL双束重建的手术中,应用本研究的结果能够简单、快捷地确定ACL前内束和后外束股骨骨道位置。     

Anatomical analysis of the anterior cruciate ligament femoral and tibial footprints

Background The current trend in anterior cruciate ligament (ACL) reconstruction has shifted to anatomical double-bundle (DB) reconstruction, which reproduces both the anteromedial bundle (AMB) and the posterolateral bundle (PLB) of the ACL. Navigation systems have also been recently introduced to orthopedic surgical procedures, including ACL reconstruction. In DB-ACL reconstruction, the femoral and tibial tunnel positions are very important, but a representation of the ACL footprint under an arthroscopic view has not been established even though navigation systems have been introduced. The purpose of this study was to evaluate the anatomical footprints of both the AMB and the PLB using the representation method for application to arthroscopic DB-ACL reconstruction using a navigation system, and to evaluate the validity of the currently determined footprint position compared with other representation methods. Methods Thirty-six cadaveric knees were used for an anatomical evaluation of footprints of the AMB and PLB. On the tibial side, the ACL footprints were evaluated using an original method. On the femoral side, the ACL footprints were evaluated using Watanabe’s method and three other methods: (1) the quadrant method, (2) Mochizuki’s method, and (3) Takahashi’s method. Results The central points of the ACL footprints were represented almost constantly. The present data is in accordance with previous measurement data. Conclusion This study showed that the anatomical data of the ACL femoral and tibial footprints determined with Watanabe’s method at the femoral side and our original method at the tibial side were both applicable to arthroscopic surgery with a navigation system.     

The contribution of each anterior cruciate ligament bundle to the Lachman test: a cadaver investigation

The clinical diagnosis of a partial tear of the anterior cruciate ligament (ACL) is still subject to debate. Little is known about the contribution of each ACL bundle during the Lachman test. We investigated this using six fresh-frozen cadaveric lower limbs. Screws were placed in the femora and tibiae as fixed landmarks for digitisation of the bone positions. The femur was secured horizontally in a clamp. A metal hook was screwed to the tibial tubercle and used to apply a load of 150?N directed anteroposteriorly to the tibia to simulate the Lachman test. The knees then received constant axial compression and 3D knee kinematic data were collected by digitising the screw head positions in 30° flexion under each test condition. Measurements of tibial translation and rotation were made, first with the ACL intact, then after sequential cutting of the ACL bundles, and finally after complete division of the ACL. Two-way analysis of variance analysis was performed. During the Lachman test, in all knees and in all test conditions, lateral tibial translation exceeded that on the medial side. With an intact ACL, both anterior and lateral tibial landmarks translated significantly more than those on the medial side (p < 0.001). With sequential division of the ACL bundles, selective cutting of the posterolateral bundle (PLB) did not increase translation of any landmark compared with when the ACL remained intact. Cutting the anteromedial bundle (AMB) resulted in an increased anterior translation of all landmarks. Compared to the intact ACL, when the ACL was fully transected a significant increase in anterior translation of all landmarks occurred (p < 0.001). However, anterior tibial translation was almost identical after AMB or complete ACL division. We found that the AMB confers its most significant contribution to tibial translation during the Lachman test, whereas the PLB has a negligible effect on anterior translation. Section of the PLB had a greater effect on increasing the internal rotation of the tibia than the AMB. However, its contribution of a mean of 2.8° amplitude remains low. The clinical relevance of our investigation suggests that, based on anterior tibial translation only, one cannot distinguish between a full ACL and an isolated AMB tear. Isolated PLB tears cannot be detected solely by the Lachman test, as this bundle probably contributes more resistance to the pivot shift.     

The Arthroscopic Appearance of a Normal Anterior Cruciate Ligament in a Posterior Cruciate Ligament–Deficient Knee: The Posterolateral Bundle (PLB) Sign

Partial anterior cruciate ligament (ACL) tears that result in functional instability are usually the result of a deficiency of the anteromedial bundle (AMB), and are evident arthroscopically by a prominent posterolateral bundle (PLB). As double-bundle ACL reconstructions are being suggested to recreate a more normal anatomy, the roles of each bundle are being more critically questioned. We present a case that describes the appearance of a normal ACL in a posterior cruciate ligament (PCL)-deficient knee in which the PLB of the ACL is prominent, giving the appearance of a complete tear of the AMB of the ACL, and scarring of this bundle to the PCL stump. On further inspection, and when the tibia was reduced, the normal appearance of the ACL returned, with visualization of the AMB obscuring the PLB. We have named this arthroscopic finding the “PLB sign.” This finding confirms the individual roles of each bundle of the ACL. It is important to not misinterpret this abnormal appearance of the ACL as a partial ACL tear in a PCL-deficient knee.     

Primary repair plus intra-articular iliotibial band augmentation in the treatment of an acute anterior cruciate ligament rupture

Between September 1987 and November 1989, we treated 90 consecutive patients with an acute anterior cruciate ligament (ACL) rupture with the multiple suture technique and iliotibial band augmentation. Seventy of these patients were re-examined 2 to 5 years after the operation (mean 3.5 years), the examination consisting of a questionnaire, clinical examination, laxity tests with the KSS machine (Acufex), radiological examination and isokinetic muscle strength testing (Cybex 6000). There were 32 men and 38 women (mean age 34 years). The injury was sustained in sports in 44 (63%) cases, and the sports most frequently involved were downhill skiing (18 cases), soccer (9 cases) and volleyball (5 cases). Of the injuries, 38 were isolated ACL ruptures and 31, ACL ruptures combined with a medial CL rupture. In 9 cases, an additional meniscus injury and in one case an additional posterior CL - lateral CL rupture was found. At the follow-up, 55 patients (79%) were satisfied with the end result, and according to our objective functional criteria 55 (79%) had an excellent or good outcome. According to the Lysholm score, 53 (76%) patients were excellent or good ( 82 points). In the Lachman test, 29 knees (41%) were completely stable. The Lachman test was mildy positive in 40 knees (57%) (36 had 1+ laxity and 4, 2+ laxity), and one patient had 3+ laxity with a hard end-point. Similarly, the anterior drawer test was negative in 53 knees (76%); and the other 17 (24%) had mild laxity (16 had 1+ laxity and 1, 2+ laxity). The total anterior-posterior laxity measured with the KSS averaged 9.7 ± 3.5 mm in the injured knee and 7.3 + 3.0 mm in the uninjured knee (the laxity measured at a knee angle of 20° of flexion). Corresponding values at a knee angle of 90° of flexion were 6.1 ± 2.4 mm and 4.7 ± 1.9 mm, respectively. The pivot shift test was negative in 62 patients (89%) and l+ positive in the remaining 8 patients (11%). Fifty-eight patients (83%) had full knee extension and 40 patients (57%), full knee flexion. Compared with the uninjured knee, the operated knees showed an average 14% strength deficit in isokinetic knee extension and 6% deficit in flexion at the speed of 60°/s. At the speed of 180°/s, the corresponding deficits were 8% and 4%, respectively. Of the 44 patients who were active in sport before the injury, 40 (91%) were able to return to sports. A flexion deficit of 5° or more was associated with thigh muscle atrophy (P < 0.05) and quadriceps weakness, both at the slow speed (P < 0.05) and high speed (P < 0.001) of the isokinetic movement. In conclusion, in an acute rupture of the ACL, primary repair of the ligament with intraarticular iliotibial band augmentation seems to be a good method to restore the functional capacity of the injured knee.     

Electron microscopic evaluation of two-bundle anatomically reconstructed anterior cruciate ligament graft

We investigated the difference in collagen fibrils in the two-bundle anatomically reconstructed anterior cruciate ligament (ACL) and the one-bundle reconstructed ACL. Ten patients with a two-bundle anatomically reconstructed ACL using semitendinosus tendons (Two-ST) were followed for an average of 16 months (7–27 months) and were compared with 15 patients with a one-bundle ACL (One-ST) reconstruction using hamstring tendons followed for an average of 20 months (9–39 months). Biopsy was performed during second-look arthroscopy. The diameter of the collagen fibrils, their density, and the percentage of collagen fibrils were measured using electron micrography. We also investigated biopsy specimens of normal semitendinosus and gracilis tendons from 10 patients. The diameter of the collagen fibrils from hamstring tendons in the Two-ST (45.1 ± 7.6nm) was significantly larger than that in the One-ST (40.1 ± 7.8nm) (P 0.05). The diameter of the collagen fibrils in the normal hamstring tendons was significantly larger than that in the reconstructed ACL with hamstring tendons of the Two-ST and One-ST groups (P 0.01). The results of the study revealed that the diameter of collagen fibrils in the Two-ST was significantly greater than that in the One-ST. Hence, the tensile strength of the two-bundle graft may be greater than that of the one-bundle graft.     

Can physical examination predict the intraarticular tear pattern of the anterior cruciate ligament?

Purpose

We evaluated the correlation between physical examinations and the tear patterns of the anterior cruciate ligament (ACL).

Materials and methods

From January 2003 to May 2007, we reviewed 201 cases of ACL rupture, diagnosed by MRI. Two orthopaedic surgeons (a fellow and a senior surgeon) evaluated the instability of the knee under anaesthesia: physical examinations were the anterior draw test (AD), Lachman test (LT), and pivot shift test (PT). By describing the rupture pattern and the site of the anteromedial (AMB) and posterolateral bundle (PLB) during arthroscopic examination, we analysed the correlation between the physical examination under anaesthesia and arthroscopic findings.

Results

In terms of the arthroscopic findings, rupture of the PLB was seen in 83 cases (41.3 %), of the AMB in 24 cases (11.9 %), and of both bundles in 94 cases (46.8 %). The kappa values for the physical examinations between the examiners were 0.963 (AD), 0.92 (LT), and 0.865 (PT). AD and LT above grade 2 did not differ significantly according to the pattern of rupture, but a PT above grade 2 was significantly different in ruptured PLB versus complete rupture.

Conclusions

A PT of more than grade 2 is a reliable physical examination for prediction of ruptured PLB or complete rupture.     

Biomechanical function of the posterior horn of the medial meniscus: a human cadaveric study

Partial and total meniscectomies have been known to develop a high rate of osteoarthritis, but not in quantitative terms. In this study, we investigated the role of the posterior horn of the medial meniscus (PMM) by measuring the changes in the multiple degrees of freedom knee kinematics. Using a robotic/universal force-moment testing system, the 5-degree-of-freedom kinematics at selected flexion angles of human cadaveric knees (age, 35–72 years) in response to a 10N·m varus torque were measured. Ten knees were studied with the knee at full extension and at 30°, 60°, and 90° of flexion. Each knee was tested in a series of four conditions: intact, with one-third of PMM resected, with two-thirds PMM resected, and finally with the entire PMM resected. Anterior tibial translation increased significantly by 1.4mm and 4.1mm at 30° of knee flexion when the two-thirds and entire PMM were resected, respectively. Similarly, external tibial rotation significantly increased 2.2° and 6.7° at 30° of knee flexion with the two-thirds and entire PMM resected, respectively. These results suggest that resecting more than two-thirds of the PMM will have a significant effect on the kinematics of the knee.     

The Complex Relationship Between In Vivo ACL Elongation and Knee Kinematics During Walking and Running

In vivo anterior cruciate ligament (ACL) bundle (anteromedial bundle [AMB] and posterolateral bundle [PLB]) relative elongation during walking and running remain unknown. In this study, we aimed to investigate in vivo ACL relative elongation over the full gait cycle during walking and running. Ten healthy volunteers walked and ran at a self‐selected pace on an instrumented treadmill while biplane radiographs of the knee were acquired at 100 Hz (walking) and 150 Hz (running). Tibiofemoral kinematics were determined using a validated model‐based tracking process. The boundaries of ACL insertions were identified using high‐resolution magnetic resonance imaging (MRI). The AMB and PLB centroid‐to‐centroid distances were calculated from the tracked bone motions, and these bundle lengths were normalized to their respective lengths on MRI to calculate relative elongation. Maximum AMB relative elongation during running (6.7 ± 2.1%) was significantly greater than walking (5.0 ± 1.7%, p = 0.043), whereas the maximum PLB relative elongation during running (1.1 ± 2.1%) was significantly smaller than walking (3.4 ± 2.3%, p = 0.014). During running, the maximum AMB relative elongation was significantly greater than the maximum PLB relative elongation (p < 0.001). ACL relative elongations were correlated with tibiofemoral six degree‐of‐freedom kinematics. The AMB and PLB demonstrate similar elongation patterns but different amounts of relative elongation during walking and running. The complex relationship observed between ACL relative elongation and knee kinematics indicates that ACL relative elongation is impacted by tibiofemoral kinematic parameters in addition to flexion/extension. These findings suggest that ACL strain is region‐specific during walking and running. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1920–1928, 2019     

The measurement of anterior cruciate ligament strain in vivo

Summary This article describes the use of the Hall Effect strain transducer (HEST) in a new arthroscopic technique to study the normal anterior cruciate ligament (ACL) in-vivo. Study participants were patient volunteers with normal ACLs undergoing diagnostic arthroscopic or meniscal surgery under local anaesthesia. The HEST was implanted into the Anterior Medial Band (AMB) of the ACL. Anterior shear loading of the tibia in relation to the fixed femur at 30° of knee flexion (Lachman test), produced significantly greater strain values in comparison to anterior shear loading at 90° (Anterior Drawer test). During isometric quadriceps contraction a significant increase in AMB strain was measured with the knee flexed to 30°, while no significant change was measured at 90°. For quadriceps contraction there were significantly higher values of AMB strain measured at 30° of knee flexion in comparison to that observed at 90°. For active range of motion (AROM) the AMB was strained between 10° and 48°, and unstrained between 48° and 110°. During passive range of motion (PROM) the AMB remained unstrained until the joint was brought into extension. There were significant differences in strain values found between AROM and PROM at the flexion angles 10°, 20°, 30° and 40°, while between 50° and 110° there were no significant differences. These results confirm previous studies that the Lachman test is a superior technique in comparison to the classic anterior drawer test for evaluating the AMB. They suggest that isometric quadriceps activity at 90° of knee flexion can be prescribed for rehabilitation immediately after ACL reconstruction. These data indicate that AROM (between the limits of 50° and 110°) and PROM may also be performed with minimal risk of strain to a reconstructive replacement. The PROM data may also serve as an important standard for the reconstruction of the ACL.

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Résumé Cet article décrit l'utilisation du transducteur de tension par effet Hall (TTEH) dans une nouvelle technique arthroscopique pour étudier le ligament croisé antérieur (LCA) normal in vivo. Les participants à l'étude étaient des patients volontaires avec LCA normal, soumis à une arthroscopie à visée diagnostique ou à une intervention sur un ménisque, sous anesthésie locale. Le TTEH fut implanté dans la bande médiane antérieure (BMA) du LCA. La translation antérieure du tibia, le fémur étant fixé et le genou fléchi à 30° (test de Lachman), donne des chiffres de tension sensiblement plus élevés par rapport à ceux obtenus en flexion à 90° (épreuve de tiroir antérieur). Lors de la contraction isométrique du quadriceps, une augmentation significative de la tension de la BMA a été notée, le genou fléchi à 30°, alors qu'aucune modification n'était mesurable à 90°. Lors des contractions du quadriceps, les chiffres de tension de la BMA, le genou fléchi à 30° étaient notablement supérieurs à ceux enregistrés à 90°. Dans le secteur de mobilité active, la BMA était sous tension entre 10° et 48° et ne l'était pas de 48° à 110°. Durant la mobilisation passive la BMA restait détendue jusqu'à ce que l'articulation soit mise en extension complète. On a trouvé des différences significatives entre les tensions mesurées lors des mobilisations actives et passives aux angles de flexion de 10°, 20°, 30° et 40°, alors qu'il n'y en avait pas de 50° à 110°. Ces résultats confirment les études antérieures selon lesquelles le test de Lachman est une technique d'examen plus sensible que la classique recherche du tiroir antérieur pour évaluer la BMA. Ces résultats laissent à penser que l'activité isométrique du quadriceps, le genou fléchi à 90°, peut être prescrite pour la réeducation, immédiatement après reconstruction du LCA. Ces données indiquent également que la mobilisation active (entre 50° et 110°) et la mobilisation passive peuvent être effectuées avec des risques mineurs après reconstruction. Les données concernant la mobilité passive peuvent aussi fournir des repères valables pour la reconstruction du LLA.

     

Application of a computerised navigation technique to assist arthroscopic anterior cruciate ligament reconstruction

Purpose

Based on biomechanical cadaver studies, anatomical double-bundle reconstruction of the anterior cruciate ligament (ACL) was introduced to achieve better stability in the knee, particularly in respect of rotatory loads. Previously, the success of ACL reconstruction was believed to be mainly dependent on correct positioning of the graft, irrespective of the number of bundles for which computer-assisted surgery was developed to avoid malpositioning of the tunnel. The aim of this study was to compare rotational and translational stability after computer-navigated standard single-bundle and anatomical double-bundle ACL reconstruction.

Methods

The authors investigated 42 consecutive patients who had undergone the single-bundle or double-bundle ACL reconstruction procedure using autogenous hamstring tendon grafts and ENDOBUTTON fixation in patients who had been followed up for a minimum of 24 months. Post-operative anteroposterior and rotational laxity was measured with the KT3000 and compared between groups.

Results

Both surgical procedures significantly improve rotational and translational stability compared to the preoperative ACL-deficient knee (P<0.05). No significant differences were registered between groups with regard to anteroposterior displacement of the tibia. The International Knee Documentation Committee (IKDC) and Lysholm scores were significantly higher in the double-bundle group. However, the results were excellent in both groups.

Conclusions

The use of computer-assisted ACL reconstruction, which is a highly accurate method of graft placement, could be useful for inexperienced surgeons to avoid malposition. Long-term results of at least five years are needed to determine whether double-bundle ACL reconstruction, which was associated with improved rotational laxity and significantly better IKDC and Lysholm scores compared to the standard single-bundle ACL reconstruction procedure, exerts an influence in terms of avoiding osteoarthritis or meniscus degeneration.     

Biomechanical characteristics of the anatomic rectangular tunnel anterior cruciate ligament reconstruction with a bone-patellar tendon-bone graft

Purpose

To clarify 1) the force sharing between two portions of BTB graft in anatomic rectangular tunnel (ART) reconstruction and 2) the knee stability in ART technique under anterior tibial load.

Effect of implant lengthening and mode of fixation on knee laxity after ACL reconstruction with an artificial ligament: a cadaveric study

An "apparent" lengthening of the ligament implant, which causes an increase in knee laxity after the reconstruction of the anterior cruciate ligament (ACL) may be due to either slippage of the implant from under the fixation devices, or tunnel migration (due to bone resorption). These two mechanisms are related to the initial ligament placement, implant tensioning, and fixation modes. This cadaveric study simulates, in a controlled experimental situation, the postoperative lengthening of artificial ACL implants, and seeks to quantify the consequent increase in joint laxity. Eight cadaveric right knees, in which the Leeds-Keio artificial ligament was implanted, were tested in a specially constructed apparatus, which allowed the knee joint six degrees of freedom. In each of the tested joints the laxity was measured under several test conditions for two final fixation modes of the implant. The difference between the fixation modes was the application (as in mode B) or not (as in mode A), of a posteriorly directed force of 50 N on the tibia, at the moment of final fixation of the ligament. In both cases a tensile load of 50 N was maintained along the implant. All measurements were taken at flexion angles of 20° and 90° and with controlled implant lengthening of up to 3 mm in 0.5-mm increments. After implantation, adopting fixation mode B resulted in the knee exhibiting an anterior laxity considerably less than the original physiological laxity, compared with that measured after using fixation mode A. Thus at 20° of knee flexion, under an anterior load of 100 N applied on the tibia, adopting fixation mode B, the joint laxity was 2.8 mm smaller than the natural laxity, whereas, for fixation mode A, it was 1.4 mm larger. At 90° of knee flexion, the situation was similar, but with smaller differences. However, the situation was overturned as the implant length was increased. Thus, at 20° of knee flexion, when the implant was lengthened in a range of 1–2 mm, the laxity observed with fixation mode B was similar to that recorded when the ACL was intact, whereas the laxity observed with fixation mode A was about 3–4 mm greater. Similar data were observed at 90° of knee flexion. It appears that fixing the implant finally by applying a tensile load on it while simultaneously pushing the tibia posteriorly could be an effective measure against the possible return of joint laxity. Received: September 12, 2000 / Accepted: January 18, 2001     

关节镜下部分重建治疗膝关节前交叉韧带不完全断裂

目的 探讨前交叉韧带(ACL)不完全断裂的关节镜下诊断及镜下部分蕈建治疗的疗效和意义. 方法 2004年6月至2006年12月,经关节镜确诊ACL不完伞断裂29例,其中前内侧束断裂21例,后外侧束断裂8例.全部患者于关节镜下重建损伤部分的韧带组织,选用LARS韧带蕈建11例,自体四股腘绳肌腱移植重建18例,术中完整保留未断裂部分的切带纤维束. 结果全部患者均获随访,平均随访15个月(12～30个月),治疗康复12个月时,门诊进行统一标准膝关节功能评定,膝关节Lysholm评分手术前、后比较差异有统计学意义(P<0.05). 结论正常ACL的前内侧束和后外侧束各自有不同的功能,对于ACL不完全断裂,准确判断ACL的断裂程度十分重要.有效地重建断裂部分的ACL,能够恢复双束韧带的完整统一,更有益于良好地恢复关节功能,避免晚期并发症的发生,对恢复膝关节稳定和功能有着重要的意义.     

Effects of femoral tunnel placement on knee laxity and forces in an anterior cruciate ligament graft.

The purpose of this study was to measure the effects of variation in placement of the femoral tunnel upon knee laxity, graft pretension required to restore normal anterior-posterior (AP) laxity and graft forces following anterior cruciate ligament (ACL) reconstruction. Two variants in tunnel position were studied: (1) AP position along the medial border of the lateral femoral condyle (at a standard 11 o'clock notch orientation) and (2) orientation along the arc of the femoral notch (o'clock position) at a fixed distance of 6-7 mm anterior to the posterior wall. AP laxity and forces in the native ACL were measured in fresh frozen cadaveric knee specimens during passive knee flexion-extension under the following modes of tibial loading: no external tibial force, anterior tibial force, varus-valgus moment, and internal-external tibial torque. One group (15 specimens) was used to determine effects of AP tunnel placement, while a second group (14 specimens) was used to study variations in o'clock position of the femoral tunnel within the femoral notch. A bone-patellar tendon-bone graft was placed into a femoral tunnel centered at a point 6-7 mm anterior to the posterior wall at the 11 o'clock position in the femoral notch. A graft pretension was determined such that AP laxity of the knee at 30 deg of flexion was restored to within 1 mm of normal; this was termed the laxity match pretension. All tests were repeated with a graft in the standard 11 o'clock tunnel, and then with a graft in tunnels placed at other selected positions. Varying placement of the femoral tunnel 1 h clockwise or counterclockwise from the 11 o'clock position did not significantly affect any biomechanical parameter measured in this study, nor did placing the graft 2.5 mm posteriorly within the standard 11 o'clock femoral tunnel. Placing the graft in a tunnel 5.0 mm anterior to the standard 11 o'clock tunnel increased the mean laxity match pretension by 16.8 N (62%) and produced a knee which was on average 1.7 mm more lax than normal at 10 deg of flexion and 4.2 mm less lax at 90 deg. During passive knee flexion-extension testing, mean graft forces with the 5.0 mm anterior tunnel were significantly higher than corresponding means with the standard 11 o'clock tunnel between 40 and 90 deg of flexion for all modes of constant tibial loading. These results indicate that AP positioning of the femoral tunnel at the 11 o'clock position is more critical than o'clock positioning in terms of restoring normal levels of graft force and knee laxity profiles at the time of ACL reconstruction.     

Recombinant human-type SOD attenuates circulatory disorders after reperfusion of splanchnic organs in rats

Oxygen free radicals (OFRs) have been reported to play pivotal roles in the pathogenesis of cell damage induced by ischemia and reperfusion. The efficacy of recombinant human superoxide dismutase (rh-SOD) in the treatment of circulatory disorders after reperfusion of the splanchnic area was investigated in rats. All rats died within 3 hours after release of 60-min superior mesenteric artery occlusion (SMAO) when no treatment was given. Animals which received rh-SOD, 2mg·100g^–1BW, at reperfusion followed by a continuous infusion of rh-SOD 0.67mg·100g^–1BW·hr^–1, exhibited prolonged survival times compared with no treatment rats (231 ± 35min and 149 ± 43min, respectively). Mean blood pressure in rats treated with rh-SOD was higher than in controls after reperfusion, and was concomitant with improvement in splanchnic perfusion. The results suggest excessive activity of OFRs in reperfused organs and a possible scavenging effect of rh-SOD as a means of eliminating them.(Bitoh H: Recombinant human-type SOD attenuates circulatory disorders after reperfusion of splanchnic organs in rats. J Anesth 6: 247–254, 1992)     

Kniegelenklaxizität beim vorderen Kreuzbandersatz

Background

The use of interference screws for femoral graft fixation in anterior cruciate ligament (ACL) reconstruction with hamstring grafts can result in rotation of the graft around the screw leading to changes in the final position of the graft within the bone tunnel.

Material and methods

In a prospective study 107 patients (54 right and 53 left knees) underwent ACL reconstruction with a hamstring tendon autograft. Femoral fixation of the graft was performed with a standard right-thread screw in all cases. Patients were assessed at 6 months postoperatively with the international knee documentation committee (IKDC) standard evaluation including instrumented laxity measurements and the results were compared between right and left knees.

Results

A significantly higher postoperative anterior laxity was observed in left knees with a negative Lachman test in only 64 % of the cases compared with 87 % in the group of right knees. Accordingly, instrumented laxity measurements of the reconstructed knee compared with the contralateral knee revealed significant differences between left and right knees (left knees 1.8±1.2 mm and right knees 1.0±1.4 mm)

Conclusions

This study demonstrates the importance of femoral graft positioning and its sensitivity to multiple influencing factors. The use of standard right-thread interference screws for femoral graft fixation in the mirrored situation of right and left knees may produce a systematic error in ACL reconstruction. Due to a possible rotation of the graft around the screw, the final position of the transplant may vary thus leading to significant changes in anterior translation of the operated knee.     

Effects of intravenous or endotracheal lidocaine on circulatory changes during Recovery from general anesthesia

Intravenous lidocaine (1.5mg·kg^–1) was not effective in attenuating the circulatory changes and the cough reflex induced by airway stimulation during recovery from general anesthesia, whereas endotracheal 4% lidocaine (3ml) was effective. The arterial concentration of the intravenously administered-lidocaine peaked at a level of 9.52 ± 0.81µg·ml^–1 0.5min later. The arterial concentration of the endotracheally administered-lidocaine peaked at 1.44 ± 0.13µg·ml^–1 15min later. These findings indicate that the endotracheal administration of lidocaine may be superior to the intravenous administration for attenuating the circulatory changes and the cough reflex during recovery from general anesthesia, and that the arterial concentration of lidocaine did not correlate with the clinical efficacy for this purpose.(Okuda M, Furuhashi K, Konishi K et al.: Effects of intravenous or endotracheal lidocaine on circulatory changes during recovery from general anesthesia. J Anesth 4: 331–336, 1990)