Revisionsersatz des vorderen Kreuzbandes

With increasing numbers of primary anterior cruciate ligament reconstruction, the incidence of unsatisfactory results and graft failures will increase. The goals of revision reconstruction are similar to those of primary reconstruction and include stabilization of the knee, prevention of secondary degenerative changes, and recovery of knee function. Besides the recurrent tear there are specific technical failures, such as tunnel malplacement and unrecognized associated ligamentous pathologies, which might lead to graft failure. Thus, preoperative planning includes a detailed analysis of failure mechanisms by thorough preoperative history taking, comprehensive physical examination, and appropriate radiographic evaluation. The treatment algorithm addresses issues of hardware removal, need for a staged procedure or concomitant surgery, graft source, tunnel placement, and graft fixation. Correct placement of tunnels and graft fixation are the essential surgical steps, which might also influence graft selection. Successful revision ACL surgery requires a motivated and compliant patient and an experienced surgeon who is proficient in a variety of different surgical techniques. However, since clinical outcome is reported to be inferior in revision compared to primary ACL reconstruction the importance of counseling the patient preoperatively regarding less satisfactory results than in most primary ACL reconstructions must be emphasized. This article describes indications, analysis and surgical procedures for revision anterior cruciate ligament reconstruction.     

Anatomische Rekonstruktion des vorderen Kreuzbandes

Background

The anterior cruciate ligament can be distinguished into two functional bundles: anteromedial (AM) and posterolateral (PL). Most commonly ACL reconstruction is performed using a single-bundle technique using one tunnel in the femur and one in the tibia. The purpose of this study is to describe a technique for an anatomical approach in ACL reconstruction restoring both bundles of the ACL.

Material and methods

For reconstruction of the AM and PL bundles, two soft tissue grafts are fixed in two separate femoral and two converging tibial tunnels. The femoral tunnel for the PL bundle is created first through an accessory medial portal. Next two converging tibial tunnels are drilled resulting in an oval-shaped exit on the articular surface of the tibia. The PL bundle graft is inserted first and the AM bundle second.

Results

The anatomical ACL reconstruction is capable of restoring the anatomy of the native ACL more closely; however, this technique is time consuming. Placing the femoral PL tunnel is technically challenging and requires detailed anatomical background knowledge.

Conclusion

The theoretical advantages of anatomical ACL reconstructions have to be proven in clinical use.     

Anatomische Rekonstruktion des vorderen Kreuzbandes

Zusammenfassung Das vordere Kreuzband (VKB) besteht aus verschiedenen Faserbündeln, die unter funktionellen Gesichtspunkten in ein anteromediales (AM) und ein posterolaterales Bündel (PL) unterteilt werden. Biomechanische Untersuchungen haben gezeigt, dass das anteromediale Bündel hauptsächlich gegen die anteriore Translation stabilisiert, dem posterolateralen Bündel jedoch eine wichtige Rolle bei der Rotationssicherung des Kniegelenks zukommt. Bisherige Techniken zur VKB-Rekonstruktion wurden dieser Anatomie nicht gerecht. Fehler waren eine zu posteriore tibiale Tunnelpostion und ein hoher femoraler Tunnel. Insbesondere bei transtibialer Bohrtechnik besteht die Gefahr einer hohen Platzierung des femoralen Tunnels. Die Folge ist ein steiles hohes Transplantat, welches das Knie nur unzureichend gegen die anteriore tibiale Translation oder auch gegen Rotationskräfte sichern kann.Die Funktion des VKB kann jedoch nur wieder hergestellt werden, wenn bei der Platzierung der Transplantate die Anatomie des normalen VKB beachtet wird. Bei der femoralen Tunnelplatzierung erlaubt das Bohren über das mediale Portal eine größere Freiheit als bei transtibialer Bohrung, bei der die Richtung des femoralen Tunnels weitgehend durch den tibialen Tunnel vorgegeben wird. Außerdem ist die Übersicht über den dreidimensionalen femoralen VKB-Ursprung besser, wenn das Arthroskop in einem medialen Portal platziert wird. Erst dann wird der gesamte Ursprung sichtbar. Das AM-Bündel entspringt im oberen hinteren Anteil, das PL-Bündel im unteren vorderen Anteil des femoralen Ursprungs. Tibial inseriert das AM-Bündel in Höhe des Außenmeniskusvorderhorns; die Insertionsstelle des PL-Bündels findet sich ca. 8 mm anterior vom HKB entfernt.Da das AM-Bündel in Streckung entspannt ist, kann es sich in dieser Stellung um den vorderen Rand der Fossa intercondylaris winden. Dieser Kontakt zwischen VKB und Fossa intercondylaris kann als physiologisches Impingement bezeichnet werden. Ein pathologisches Impingement besteht, wenn ein Kreuzbandtransplantat durch das Anstoßen an den vorderen Rand der Fossa intercondylaris zu einem Bewegungsdefizit führt. Der Grund für ein pathologisches Impingement wurde früher mit der tibialen Tunnelpositionierung begründet. Eine posteriore tibiale Tunnelposition sollte zur Verhinderung eines pathologischen Impingements beitragen, wobei die femorale Tunelpositionierung eher unbeachtet blieb. Allerdings kommt es bei Platzierung des femoralen Tunnels im Bereich des Daches der Fossa intercondylaris eher zu einem pathologischen Impingement als bei einem flacheren Transplantat, wenn der femorale Tunnel im Ursprung des VKB platziert wird.     

Ersatzplastik des vorderen Kreuzbandes bei offenen Wachstumsfugen

The natural history of ligamentous tears of the anterior cruciate ligament (ACL) in children is unfavourable because of the high number of secondary meniscus lesions and early manifestation of osteoarthritis. Although their incidence still is relatively small, the number of ACL tears in children has increased over the last years. There is controversy about the treatment of these lesions, especially considering the long-term conservative approach. Recent studies have shown that ACL reconstructions in children can yield good clinical results and few complications if performed in a technically correct way with respect to the specific anatomy of childrens knees – even before puberty. The functional demands of the patient and the complication potential should be considered while indicating the procedure. A precise knowledge of the anatomical specificities of the childs knee and a large experience in ACL reconstruction surgery should be mandatory when taking care of these injuries. The present review gives a current overview of the management of these lesions in pre-adolescent children.     

Revisionsrekonstruktion des vorderen Kreuzbandes mit begleitender Korrekturosteotomie

ACL revision reconstruction and simultaneous osteotomy is indicated in patients with recurrent instability and symptomatic malalignement. Detailed clinical examination is essential for finding of subjective main pathology. Extensive apparative screening helps avoiding serious intraoperative complications. This includes weight bearing, x-rays in full extension and 30° flexion and CT scan for evaluation of bone cavity measurement. According to IKDC rating scale ACL revision reconstruction and simultaneous osteotomy rarely leads to excellent results (1/19) due to the preexisting cartilage damage but significantly increases quality of life (18/19) of these patients.     

Computerassistierte Rekonstruktion des vorderen Kreuzbandes mit dem Navigationssystem

The computed-navigated technique for surgical repair of the anterior cruciate ligament enables even less experienced surgeons to correctly place drilling channels. The safety of navigated channel drilling was documented by comprehensive anatomical studies and use of the system by assistants. Employment of the computed-navigated technique for reconstruction of the anterior cruciate ligament can be beneficial to both patients and health insurance providers by ensuring accuracy of the procedure.     

Rekonstruktion des vorderen Kreuzbandes mit der Einbündeltechnik

When employing the single-bundle technique for ACL reconstruction the goal is to achieve optimal positioning of the tibial and femoral tunnels. If the femoral tunnel is placed with the transtibial technique (single-incision technique) then its localization is essentially governed by the course and length of the tibial canal. Possibilities for intraoperative correction are very limited when a tibial canal has been created; this is all the more pronounced the larger the bore of the femoral drill bit. A very sterile transplantation course can be observed in many cases using transtibial techniques with the disadvantages of inadequate rotational stability, limited mobility, and/or severe axial compression in the other joint component. Quadruple-strand semitendinosus tendon is used for surgical reconstruction. The femoral tunnel is placed via a deep medial approach for inserting the instrument at the 10 or 2 o’clock position. The anatomic insertion area should be taken into account for the tibial canal. This avoids positioning the tibial tunnel too posteriorly. Tibial and femoral fixations are carried out in the sense of a hybrid fixation with an endobutton and a bioresorbable interference screw. With the hybrid fixation, use of oversized screws is avoided and at the same time the specific advantages of each fixation technique are exploited for optimal healing of the bone transplant.     

Verletzungen des hinteren Kreuzbandes

Ohne Zusammenfassung     

Symptomatische Partialrupturen des vorderen Kreuzbands

The anterior cruciate ligament (ACL) consists of two anatomical and functional bundles, the anteromedial (AM) and posterolateral (PL) bundles. Different injury pattern demonstrate a wide spectrum of partial ACL tears. Clinical interest has recently focused on performing selective ACL augmentation according to the specific injury pattern. Theoretically, sparing the intact parts of the ACL may increase vascularization and proprioception, can optimize the accuracy of ACL reconstruction and result in better stability and improved clinical outcome for the patient. However, isolated reconstruction of the AM or PL bundle is an advanced arthroscopic procedure that requires precise preoperative and intraoperative diagnostic assessment of the injury pattern, exact anatomical definition of the insertion sites and careful debridement and bone tunnel placement while preserving the intact parts of the ACL. This article presents the concept of partial ACL rupture, describes the clinical, radiological and arthroscopic assessment of partial tears as well as the arthroscopic reconstruction.     

Entwicklung eines Zielgeräts für den femoralen posterolateralen Bohrkanal in der Zweibündelrekonstruktion des vorderen Kreuzbandes (VKB-db-Reko)

Due to recent biomechanical studies the reconstruction of the anterior cruciate ligament in double bundle technique is widely recommended. Correct placement of the tunnels is essential for good clinical outcome. Drill guides are commonly used for the placement of tunnels. The described surgical technique places the posterolateral tunnel depending on the anteromedial tunnel. Due to the different orientation of the tunnels, a new drill guide with a flattened hook was developed for the posterolateral tunnel.     

Verschiedene Techniken zur Ersatzplastik des vorderen Kreuzbands

A wide variety of proven methods for anterior cruciate ligament (ACL) surgery is known for treating a very mixed group of patients. The gold standard for ACL replacement today is anatomic single bundle reconstruction using hamstring tendon, patellar tendon or quadriceps tendon as autologous graft. An indication for ACL double bundle reconstruction is seen in patients with large insertion zones. The double bundle concept also includes replacement of a partial rupture or remnant augmentation. Graft choice should be adapted to the individual patient. For specific graft choice age, gender, activity, sports, professional and religious habits should be considered.