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PubMedDate not supplied

[Arthroscopy techniques in the treatment of extension contractures of the knee joint after total knee arthroplasty].

Results are analyzed of treatment of four patients presenting with extension contractures of the knee joint after total knee replacement with the aid of the arthroscopic arthrolysis technique. All patients demonstrated increase in the joint movement size. The conclusion reached was that in the incipient manifestations of the knee joint extension contractures, the arthroscopic arthrolysis technique is superior to the conventional one.

Adult↗
PubMed1977

[Systematy of artificial knee joints considering constructional characteristics of the natural knee joint (author's transl)].

The subject of this investigation is to spezify artifical knee joints. For this purpose the most important constructional peculiarities and functions of the natural knee joints are to be opposed to them of the artificial ones. This analysis is based on the kinematic and theory of construction. The systematy distinguishs the various artificial knee joints considering the characteristics that are thought to be substantial.

Biomechanical Phenomena↗
PubMed1981

[On the cause of the anterolateral instability of the knee joint. A study on 20 cadaver knee joints with special regard to the tractus iliotibialis (author's transl)].

Experiments on 20 cadaver knee joints are reported on. A short medial incision was made to transect the anterior cruciate ligament. Through a long lateral incision the lateral structures (lateral capsule, lateral collateral ligament, and iliotibial tract) were transected in variable series to check their influence on the pivot shift-sign. The results are tabulated. The anterior cruciate ligament is shown to be the key structure for the pivot shift-sign. This sign is only markedly positive when the lateral structures are intact. Depending on the pattern of transection of the lateral structures the pivot shift-sign is less marked or totally absent. It is also shown why this sign is missing in the unhappy triad. Because the intact distal part of the iliotibial tract is responsible for the pivot shift-sign, a detailed description of its anatomy and physiology is given.

Fascia Lata↗
PubMed1997

Analytical study on the kinematic and dynamic behaviors of a knee joint.

A knee model in the sagittal plane is established in this study. Specifically, the model is used to study the effects of inertia, articular surfaces of the knee joint, and patella on the behaviors of a knee joint. These behaviors include the joint surface contact point, ligament forces, instantaneous center and slide/roll ratio between the femur and tibia. Model results are compared to experimental cadaver studies available in the literature, as well as between the quasistatic and dynamic models. We found that inertia increases the sliding tendency in the latter part of flexion, and lengthens the cruciate ligaments. Decreasing the curvature of the femur surface geometry tends to reduce the ligament forces and moves the contact points towards the anterior positions. The introduction of the patellar ligament in the model seems to stabilize the behaviors of the knee joint as reflected by the behavior of the instant centers and the contact point pattern on the tibia surface. Furthermore, we found that different magnitudes of the external load applied to the tibia do not alter the qualitative behaviors of the knee joint.

Anterior Cruciate Ligament↗
PubMed2003

Medical devices; reclassification of the knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis and the knee joint femorotibial (unicompartmental) metal/polymer porous-coated uncemented prosthesis. Final rule.

The Food and Drug Administration (FDA) is announcing that it has reclassified two fixed-bearing knee joint prostheses, the knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis, which is intended to be implanted to replace a knee joint, and the knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis, which is intended to be implanted to replace part of a knee joint. FDA has reclassified the devices from class III (premarket approval) into class II (special controls). The special control that will apply is a guidance document entitled "Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA." The agency is reclassifying these devices into class II because special controls, in addition to general controls, will provide reasonable assurance of the safety and effectiveness of the devices, and there is sufficient information to establish special controls. The agency is also announcing that it has issued an order in the form of a letter to the Orthopedic Surgical Manufacturers Association (OSMA) reclassifying the devices.

Device Approval↗
PubMed1978

[Electromyographic examination of the femoral muscles in hemophilic effusion in the knee-joint and in irritated conditions of the knee-joint (author's transl)].

In ten patients with acute effusion in the knee-joint due to hemophilia, or with chronic knee-joint affection, the maximal isometric contraction of the M. vastus medialis and lateralis and of the M. rectus femoris was measured by electromyography. Measurements were taken before and after puncture of the effusion, or before and after intraarticular injection of a local anesthetic. In all examined patients, the contraction tests were performed below the pain threshold. The proportionate share of energy of the quadriceps muscle was considerably enhanced by reducing the intraarticular pressure and injecting a local anesthetic. This increase differs, depending on the state of the knee-joint affection.

Acute Disease↗
PubMed1996

Anatomic bases of a vascularized allogenic knee joint transplantation: arterial blood supply of the human knee joint.

The vitality of a graft in a vascularized allogenic knee joint transplantation in humans will depend strongly on maintaining the arterial blood supply to the bone. As can be demonstrated in injected specimens on cadavers, only periostal aa. are important to ensure the blood supply of the human knee joint. The main arteries have defined nutritive areas. According to our results access to the vessels should most probably be conducted from the dorsal side of the knee. During the explantation the popliteal a. should be ligated proximally as high up as possible and distally just above its trifurcation. The articular branch of the descending genicular a. of both the donor and the recipient can be ligated because of a rich anastomotic network. The medial and lateral inferior genicular aa. of the donor should be ligated ventrally as far forward as possible. One should, above all, preserve the medial inferior genicular a. of the donor in order not to endanger the medial part of the distal segment of the graft. If an operation is to be performed according to the results of our anatomical studies, vascularized allogenic knee joint transplantations should be successful from an anatomical point of view.

Femur↗
PubMed1995

Energy cost during ambulation in transfemoral amputees: a knee joint with a mechanical swing phase control vs a knee joint with a pneumatic swing phase control.

The aim of the study was (i) to evaluate the preference of transfemoral amputees for a 4-bar linked knee joint with either a mechanical swing phase control or a pneumatic swing phase control, and (ii) to compare the energy expenditure in transfemoral amputees using a prosthesis with a mechanical swing phase control with that of the same amputees using a prosthesis with a pneumatic swing phase control. The study included 28 unilateral transfemoral amputees amputated for reasons other than chronic vascular disease. All patients had a prosthesis with a knee joint with mechanical swing phase control (the Otto Bock 3R20) before entering the study. The amputees changed their knee joint to one with pneumatic swing phase control (the Tehlin knee joint) at random either after the first or second assessment. The amputees were asked for their preference at the second and third assessments. The energy expenditure while walking at speeds of 2 and 3 km/h was measured at each assessment. After having tried both knee joints, 19 patients preferred the Tehlin knee, 6 patients preferred the Otto Bock 3R20, and 3 patients had no preference. The energy expenditure measurement showed that walking with the Tehlin knee required more energy than walking with Otto Bock 3R20. Because of the limited number of patients included in the study and the fact that a double-blind design was impossible to achieve, conclusions should be drawn with caution.

Adolescent↗
PubMed1998

Effect of the posterior cruciate ligament in knee-joint proprioception in total knee arthroplasty.

The primary purpose of the study was to examine the role of the posterior cruciate ligament (PCL) in knee-joint proprioception after total knee arthroplasty (TKA). Knee-joint proprioception was measured in 10 patients with nonsacrificed PCL TKAs and 10 with sacrificed PCL TKAs. Knee-joint proprioception was evaluated through reproduction of static knee angles using a Penny and Giles electrogoniometer. The primary variable was absolute angular error (AAE). AAE was defined as the absolute value of the difference between the test angle and the patient's perceived version of the test angle. Proprioception deficit was compared to the WOMAC questionnaire which evaluates pain, stiffness, and physical function of the lower extremity. No significant difference was found between the nonsacrificed PCL TKA (4.33 degrees +/- 1.52 degrees) and sacrificed PCL TKA (4.38 degrees +/- 1.39 degrees) AAE values (P > .4). Furthermore, no significant differences were observed in the WOMAC questionnaire scores for all three parameters between the two types of knee prosthesis (P > .35). The current findings suggest that the preservation of the PCL in TKA may not improve knee-joint proprioception and subsequently may not improve TKA functional performance.

Aged↗
PubMedDate not supplied

[Regenerative processes of the internal structures of the knee joint following meniscectomy. Experimental study of the knee joint of the rabbit].

In an experimental study of thirty rabbits, processes of repairing of the inner structures in the knee joint after meniscectomy were examined: Three operational methods were used: The total, partial and sub-partial menisectomy. Macroscopic, microscopic and electron microscopic examinations of the inner structure of the knee joint were made after intervals of one, three, six, nine and twelve weeks after meniscectomy. Processes of adaptation in the articulating parts of the joints were detected after total and sub-total menisectomy. These were in the form of marginally located chrondo-osteophytic deposits. Very little change or no change at all could be found in the tibia and the femur, where a sub-total meniscectomy had been performed. A regenerative development took place in the capsular part of the resection line of the meniscus and/or the anterior part of the meniscus. The regeneration consisted of connective tissue rich in collagen fibres. No cartilage tissue could be found. There was no regenerative development in evidence after performing a sub-total menisectomy. Closure of the lesion/defect to the original half moon shape was not observed. The inner edge of the meniscus base showed itself to be unchanged. Intermediate cartilage structures remaining in the joint after the performance of partial and sub-total meniscectomy showed evidence of changes in connective tissue composition. Microscopy showed changes in its connective tissue through increased layering of collagen tissue in the cartilaginous tissue matrix. Adaptation processes in the tibia and the femur after total and partial meniscectomy indicate a low functional regenerative efficiency.

Animals↗
PubMed1991

Receptors in the knee joint ligaments and their role in the biomechanics of the joint.

The knee joint ligaments contain Ruffini, Pacinian, Golgi, and free-nerve endings with different capabilities of providing the CNS with information about movement and position as well as about noxious events. Skeletomotor neurons (alpha-motoneurons) are known to be influenced only very rarely and weakly from low-threshold mechanoreceptors in the ligaments, while the effects on the tau-muscle-spindle system in the muscles around the knee are so potent that even ligament stretches at very low loads may induce major changes in the responses of the muscle spindle afferents. Since the primary muscle spindle afferents participate in the regulation of muscular stiffness, the receptors in the knee joint ligaments probably contribute, via the tau-muscle-spindle system, to preparatory adjustment (pre-setting) of the stiffness of the muscles around the knee joint, and thereby to the joint stiffness and the functional joint stability.

Afferent Pathways↗
PubMed1999

Knee joint forces during isokinetic knee extensions: a case study.

OBJECTIVE: To describe the procedures to obtain knee joint forces during isokinetic knee extensions and evaluate the patellar ligament force, quadriceps tendon force, patellofemoral and tibiofemoral joint forces at different speeds measured from a female subject. DESIGN: A technical note with a case study. BACKGROUND: Two previous studies examined knee joint forces during isokinetic knee extension using different techniques reported inconsistent findings. Also, the highest speed used in these two studies (180 degrees s(-1)) were much lower than the maximum speeds available in modern isokinetic dynamometers. METHODS: The subject performed maximum effort isokinetic knee extensions at 16 different speeds ranged from 25 to 400 degrees s(-1). The gravitational and inertial effects were included in determining the resultant knee torque. Knee radiographs were used to determine the knee joint geometry. A combination of knee torque and geometric data was used to determine different knee joint forces. RESULTS: All knee joint forces were found to decrease with increasing isokinetic speed. The tibiofemoral shears forces indicated that the anterior cruciate ligament was loaded throughout the range of motion. CONCLUSIONS: The magnitudes of knee joint forces are largely depending on the knee torque values. RELEVANCE: Isokinetic knee extensions are considered appropriate for the early part of the rehabilitation for patients with knee dysfunctions due to the lesser demand of coordination. However, to reduce the knee joint forces, submaximal efforts at lower speeds or maximal efforts at higher speeds are recommended.

Adult↗
PubMed1984

[An experimental study on the stability of the knee joint. Special reference to the mechanisms of rotatory stability of the knee joint].

In order to evaluate the stabilizing mechanisms of the ligaments, menisci and the conformity of the condylar surface, six human knee joints and five dog's knee joints were tested by the rotatory stability testing machine devised by myself. The torque-rotation curve and the amount of the up hill movement were measured under various compressive loads. Internal and external rotation were applied to the knee joint with range of 0.2 radian respectively. During rotatory movement, various compressive loads (0 kgf, 20 kgf, 40 kgf, 60 kgf, 80 kgf) were applied on the tibio-femoral joint. The following results were obtained in this study. Within a range of 0.2 radian in internal and external rotation respectively, rotatory stability was almost unaffected by sectioning of the cruciate ligaments. Rotatory stability was affected significantly by sectioning the medial collateral ligament. Almost the same results were obtained by removal of the medial meniscus. The intrinsic factors, especially the medial collateral ligament and the medial meniscus, provided the stability of external rotation for the knee joint. The amount of the up hill movements were measured 0.5 mm in internal rotation, and 0.1-0.2 mm in external rotation respectively. Only after removal of the medial meniscus, the amount of the up hill movement were decreased obviously. This decreases of the up hill movement were observed in external rotation. So, it was concluded that medial meniscus has the stabilizing mechanism of external rotation by the up hill movement. The conformity of the condylar surface was an important factor in the stability of the knee joint under compressive load. Especially, it restricts internal rotation.

Adult↗
PubMedDate not supplied

[Is the implantation of hinged knee joint prostheses still justifiable today? 15 years' experience using the Blauth knee joint prosthesis].

In objection to knee hinge prostheses there is often mentioned a higher complication rate. An increased load impact on the bone-cement interface results from the close connection of tibial and femoral components. This is assumed to cause bad results, as reported from early artificial knee joint replacements, characterised by weight bearing axes and direct contact metal to metal. These are contrasted to long term results of the Blauth hinge prosthesis. The Blauth prosthesis is constructed according to the low friction principle without a weightbearing axis. A prospective multicentric long term follow-up study reports on 556 prostheses. 463 (83%) were controlled between 1 and 15 years after operation (average: 43 months). Aseptic loosenings had to be confirmed in 1.3% of the patients, deep infections in 2.6%. The survival analysis did not show an erratic deterioration in dependence of the observation period. After 10 years there is still a probability of 89% that a prosthesis does not show a deep infection or loosening. The efficiency of artificial knee joint replacement by hinge joints should therefore not be judged on the results of the first generation of these models.

Adult↗
PubMed1995

Contact pressure prediction in total knee joint replacements. Part 2: Application to the design of total knee joint replacements.

The general elasticity contact theory for elliptical geometry developed in Part 1 (1) has been applied to the design of current total knee joint replacements. A two-step curve-fitting technique using cubic spline interpolation routines has been adopted to represent the full elasticity solutions. The curve fit results of the maximum contact pressure have been compared with the full elasticity solution for a specified elliptical geometry and different polyethylene thicknesses and good agreement has been demonstrated. The computing time required by the curve-fitting technique is very small compared with the full elasticity solution and therefore can readily be applied to the design of knee joint replacements. Furthermore, reasonable agreement has also been found for the contact area for a typical knee joint design between the present theoretical prediction and the experimental measurement using pressure-sensitive film. Predictions of the maximum contact pressure have been made for an existing knee joint replacement in order to illustrate the present analysis in the design cycle. It has been shown that the effect of the thickness of ultra high molecular weight polyethylene is relatively small on contact stress predictions provided a sufficiently large value is chosen. On the other hand, the effect of conformity has a much greater influence on the contact stress distribution, particularly in the direction of the smaller principal radius.

Elasticity↗
PubMed1999

Knee joint simulator: an anatomical reconstruction of the joint surfaces and of the ligamentous structures of the knee joint for teaching purposes.

A knee joint simulator with anatomical reconstruction of the joint surfaces and of the ligamentous structures was built for teaching purposes. With this simulator it is possible to demonstrate the anatomy, physiology and kinematics of knee ligaments, to teach and learn how to conduct ligamentous instability tests and to demonstrate the effect of knee ligament reconstructive surgery.

Education, Medical↗
PubMedDate not supplied

[Mechanical effects on measuring displacement of the knee joint with the knee arthrometer KT1000 and KT2000].

The KT2000 knee ligament arthrometer manufactured by the MEDmetric Corporation is used in the field of orthopedics to establish quantitatively the size of the anterior and posterior draw phenomena of the knee joint. The basis for the measurement is the Lachman test in which a force is applied to the tibia relative to the femur. The resulting displacement is limited by the cruciate ligaments. The measurements obtained for a potentially injured knee are compared with those of the healthy knee and empirical threshold values, and serve as a basis for deciding whether to operate on patients with cruciate ligament insufficiency. The subject of the present study is a design shortcoming of the KT2000 that may falsify the measured results when the device is not correctly employed. A simple mechanical modification of the KT2000 can reduce this error. In the present study, the error is quantified and we show how the modification can keep it within tolerable limits.

Anterior Cruciate Ligament Injuries↗