[Significance of combined anterior cruciate ligament and meniscus injury]. / Bedeutung der Kombinationsverletzung von vorderem Kreuzband und Meniskus.

The combined lesion of the anterior cruciate ligament (ACL) with simultaneous or secondary meniscal tears has severe consequences for the knee joint. By a synopsis of the literature and own experimental investigations in sheep it can be shown that in ACL deficient knees secondary meniscal lesions occur, what finally ends in osteoarthrosis. The combined lesion of the ACL and the meniscus results in a more severe damage of the joint than the sum of the single lesions. ACL reconstruction in these cases is very important, because meniscal tears cannot heal in unstable knees. On the other hand resections of the menisci have to be avoided, because the loss of these secondary stabilizers and synergists of the ACL increases the risk of joint degeneration.

[Glycosaminoglycans as markers of post-traumatic gonarthrosis?]. / Glykosaminoglykane als Marker für die posttraumatische Gonarthrose?

Osteoarthritis (OA) influences the levels of free intraarticular glucosaminoglycans (GAG). Little is known about the direction--decrease/increase--of these changes, and information on the correlation between GAG levels and the degree of OA is sparse. Objectives of this study were to investigate the correlation between intraarticular levels of sulphated and unsulphated GAG and the degree of experimental OA, the time course of these changes and whether GAG might be useful as a marker for OA. Twenty-one sheep were randomly assigned to three groups: (1) transsection of the posterolateral bundle of the anterior cruciate ligament, ACL (TD), (2) medial meniscectomy (ME), and (3) meniscectomy and resection of the ACL (MV). During follow-up clinical and radiological examinations were done. After screening for intraarticular effusions, a joint tab was performed and the levels of hyaluronic acid and chondroitin sulphate were measured. The radiological scores differ significantly between group TD and groups ME and MV (P < 0.01). Hyaluronic acid levels in ME and MV are significantly higher than in the controls. Significantly increased levels (P < 0.01) of chondroitin sulphate are found 6 months after ME and 1 year following TD. Clinical consequences: Hyaluronic acid levels--at least in the experimental setting--correspond to a certain degree with osteoarthrotic changes: increasing levels were found along with increasing postoperative interval and increasing grade of OA. Chondroitin sulphate, on the other hand seems, to lend itself as a marker for chondromalacia, in other words for prearthrotic deformities and early stages of OA.

[Interspecies comparison of healing standardazed bone defects with and without autogenous bone transplantation]. / Interspeziesvergleich zur Heilung standardisierter Knochendefekte mit und ohne autogene Knochentransplantation.

This study tries to establish a basis for comparison of animal studies regarding bone defect healing. Pigs, sheep and rabbits were operated on according to a standardized scheme where each received bilateral defects of the femoral condylus. One of the defects was filled with cancellous autograft, the other remained empty. Bone defect healing was followed with several different methods of investigation, the results were put into perspective with the help of a standardized score-scheme.

[Diagnostic and therapeutic standard in meniscus lesions--results of a survey]. / Diagnostischer und therapeutischer Standard bei Meniskusläsionen--Ergebnisse einer Umfrage.

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.

[Development of replacement meniscus of autogenous tissue]. / Entwicklung eines Meniskusersatzes aus autogenem Gewebe.

At present no established therapy for the complete loss of meniscus is available. An attempt is made to create a transplant out of autogeneic tissue resembling the meniscus in its morphological and functional aspects. The middle third of the patellar tendon with proximal and distal bone blocks serves as a basis and is coated with a fascia lata strip. After temporary subcutaneous transfer, the meniscus substitute is intended for later transplantation. The theoretical ideas for the imitation of a meniscus in view of fibre architecture and biomechanical validity were tested in 14 sheep. In principal this model succeeds in imitating the fibre architecture of the menisci. After a conditioning period of 8-10 weeks in the subcutaneous tissue, the neomeniscus seems to be suitable for transplantation. The tensile strength of the grafts decreases slightly but the bone blocks stay viable.

[Lesions of the popliteus system and their significance for the stability of the knee joint]. / Läsionen des Popliteus-Systems und ihre Bedeutung für die Stabilität des Kniegelenkes.

INTRODUCTION: Stäubli 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). 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.

[Change in subchondral mineralization after reconstruction of the anterior cruciate ligament of the sheep]. / Veränderung der subchondralen Mineralisierung nach Rekonstruktion des vorderen Kreuzbands beim Schaf.

The cruciate ligaments are generally regarded as regulators of the joint kinematics, but also increasingly as a "Sensory organ" regulating the periarticular musculature, which influences the position of the contact surfaces and the direction and magnitude of the resultant forces. Indirectly, therefore, they influence the long-term stress distribution, which is itself reflected in the distribution of the subchondral mineralisation. An experimental investigation was therefore undertaken to see whether, in terms of this distribution, the distribution of the stress alters postoperatively, since this could be regarded as an early cause of degenerative change. We examined the distribution of the subchondral mineralisation of six tibiae from six adult Merino sheep 1 year after anterior cruciate ligament reconstruction with patellar tendon. The contralateral tibia we used as controls. Maximum subchondral mineralisation of both the medial and the lateral joint surfaces in all the control joints was found to be central. In the treated knees, however, the medial joint surface maxima were found to have been displaced towards the dorsomedial edge of the surface in every case. If the density pattern on the control side is accepted as the expression of a normal stress distribution, the distribution patterns on the treated side must indicate a pathologic distribution of stress. Reconstruction of the anterior cruciate ligament is therefore--at least in the animal model--not able to prevent the development of a pathologic stress distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

[Missed injuries of the musculoskeletal system in multiple trauma--a retrospective study]. / Ubersehene Verletzungen des Stütz- und Bewegungsapparats beim Polytrauma--eine retrospektive Studie.

In order to quantify frequency, localisation and consequences of missed musculoskeletal injuries in multiple injured patients, 323 cases were retrospectively analyzed. 40 primarily missed injuries were found, 12 of them in patients, who had been transferred from another hospital. This rate of 12.4% corresponds with the literature. Four regions are mainly affected: 1. the cervical spine, especially the cervicothoracic transition, 2. the shoulder, 3. the ligaments of the knee especially with femur or tibia fractures at the same time, and 4. the forefoot. About half of the primary missed injuries are ligament lesions. Whereas spine injuries were diagnosed within the first 2 weeks (average 4 days), ligament injuries (average 28 days) and foot injuries (average 38 days) were discovered at the patient's mobilization phase. Reasons for non detecting the injuries are: Missing or inadequate x-rays, not consistently continued diagnostic steps, inaccurate or not repeated clinical examination, apparent insignificance of peripheral injuries in multiple trauma. The potential danger of neurologic deficits of vertebral fractures, delay of rehabilitation due to secondary correction surgery (e.g. secondary ligament reconstructions) and imminent permanent damage (e.g. posttraumatic foot deformities) show the importance of a quick diagnosis of all injuries, even those appearing at the first glance as unimportant.