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At least 19 recordsLinked to original sources
PubMed1975

Variations in collagen, non-collagenous proteins, and hexosamine in menisci derived from osteoarthritic and rheumatoid arthritic knee joints.

Knee joint menisci from osteoarthritic and rheumatoid knees were analyzed for nitrogen, collagen, non-collagenous proteins (NCP) and hexamine content. Degenerate areas were analyzed separately. The degenerative areas were significantly lower (P less than 0.005) in collagen but NCP and hexosamines were elevated relative to control tissue. The rheumatoid menisci revealed a reduced level of collagen and hexosamine in areas of localized degeneration. However, the collagen and hexosamine content of the remaining tissue was also diminished (P less than 0.025) relative to normal tissue of the same. age.

Adult↗
PubMed1988

[Sprains and dislocations of large joints--the knee joint].

Recent "distorsion" injuries of the knee joint should be diagnosed with great precision. While injuries that do not produce instability should be treated conservatively, early surgical repair is the treatment of choice for the unstable knee. If a reliable evaluation is not possible, a general anesthetic is required; arthroscopy is reserved for special questions. Dislocation of the knee is a true surgical emergency. The vascular insult caused by the severe injury requires immediate attention.

Arthroscopy↗
PubMed1976

Stabilizing mechanisms of the loaded and unloaded knee joint.

Knee specimens were placed in an apparatus which imposed cyclic anterior-posterior or rotatory forces, with various compressive loads applied to the joint. Force-displacement graphs or torque-rotation graphs were automatically plotted, giving the laxity under various conditions. The ligaments, capsule, and menisci provided joint stability under no-load conditions. However, under compressive loads, the conformity of the condylar surfaces was an important factor in stabilizing the knee. The mechanism proposed was the uphill movement of the femur as the femur and the tibia were displaced or twisted relative to one another.

Adult↗
PubMed1976

[Knee joint prosthesis with the geomedic knee joint (author's transl)].

Thirty-one cases of plastic knee joint operations were reported. Twenty-one patients were treated with the geomedic knee. The advantage of this joint is that only a small amount of bone must be sacraficed. The range of movement is better than that with a complete knee prosthesis with axis.

Aged↗
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↗
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↗
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↗
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↗
PubMedDate not supplied

[Kinematics of various joint mechanisms for the prosthetic substitution of the knee joint following knee exarticulation].

In the past, long amputation stumps of the thigh after knee disarticulation were difficult to fit with a knee prosthesis. Apart from other difficulties, one essential problem was caused by the fact that in preservation of the femoral length there was little or even no space to assemble a knee prosthesis at the level of the axis of the natural knee joint, that is to say at a position somewhere within the femoral condyles. In the meantime the number of knee disarticulations has increased and thus substituted the conventional above knee amputation. Consequently some new, partly polycentric knee joint mechanisms have been designed for the prosthetic fitting of knee disarticulation stumps as well as for long amputation stumps of the thigh. These mechanisms try to cope with the space problem in different ways and, moreover, some of them can also produce a moving centre of rotation at joint flexion similar to the natural knee joint. The motion pattern in current knee joint mechanisms is investigated by graphical construction of their centrodes and it is compared to the motion pattern of the natural knee joint.

Artificial Limbs↗
PubMed1990

[Mobilization in anesthesia and arthrolysis in postoperative knee joint stiffness].

Knee joint stiffness first of all calls for physiotherapy, ranging from exercise therapy to a passive-immobilization splint. If no progress can be achieved, narcosis mobilization and brisement modéré should be done. If narcosis mobilization does not yield acceptable results, then surgical dissolution and arthrolysis should be performed. Thirty-seven patients with painless fibrous knee-joint stiffness following ligament reconstructions showed a reduction in mobility of 0 degree-20 degrees-80 degrees on average. After narcosis mobilization, full extension and bending could be achieved in 28 patients. In 9 patients, arthrolysis had to be carried out. At follow-up examination 1/2 to 3 1/2 years later, all 37 patients showed an increase in movement of 0 degree-0 degree-125 degrees on average. The "relative gain," the quotient of achieved and possible gain of movement in percentage, ranged from 88% to 96% on average. Other kind of loss of movement, patient age, or sex had no influence on the results. Twenty-six patients were able to participate in sports again due to the increase in movement potential. In the last few years, we have come to prefer arthroscopical arthrolysis instead of surgical arthrolysis when narcosis mobilization fails.

Adult↗
PubMed1978

Immediate effects of meniscectomy on the knee joint. The effects of tensile load on knee joint ligaments in dogs.

Tensile strength variables for the collateral ligaments were compared after excision of the meniscus in one knee, the corresponding meniscus in the contralateral knee of the same dog being intact. Removal of the meniscus was associated with a three-fold increase in initial laxity, two-fold for the lateral and three-fold for the medical ligament. The maximum tensile load uptake of the medial collateral ligament was reduced by more than 10 per cent after medial meniscectomy; the load uptake of the lateral ligament was not affected by lateral meniscectomy. It is proposed that tensile loads are distributed more favourably in the medial collateral ligament by the intact medial meniscus with firm capsular attachments than in the "normal" ligament after meniscectomy.

Animals↗
PubMedDate not supplied

Exercise-related knee joint laxity.

Knee injuries are the topic of increasingly sophisticated research because of the importance in professional athletics as well as increasing participation in recreational sports. The role of conditioning and fatigue in these injuries remains controversial. Ligaments have high collagen content, and a viscoelastic response to stress would be expected. Because of the postulated relationship between laxity and knee ligament injuries, an experiment was designed using highly motivated athletes to test the hypothesis that exercise to the point of muscular fatigue may cause laxity of the knee and thereby place athletes at risk for ligamentous injury to the knee when fatigued. An exercise protocol was designed to produce muscle fatigue in the hamstring and quadriceps muscle groups. Knee ligament laxity was tested prior to and subsequent to the exercise protocol. To document muscle fatigue, isokinetic testing of right knee flexion and extension power was used several times during the exercise protocol. A knee arthrometer (KT-1000) was used to quantitatively document ligamentous laxity before and after exercise. The results indicated a significant lengthening in knee joint laxity between preexercise and postexercise in the left knee as measured at 15 and 20 pounds of passive displacement force (P less than 0.05). Maximum manual displacement also demonstrated a significant increase in joint laxity (P = 0.02). The right knee, which had undergone isokinetic testing, demonstrated a similar tendency but without a statistically significant difference before and after exercise. There was no significant preexercise side to side difference, but postexercise measurements demonstrated a left-right difference at 15 pounds, 20 pounds, and maximum manual displacement of statistical significance (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

A planar model of the knee joint to characterize the knee extensor mechanism.

A simple planar static model of the knee joint was developed to calculate effective moment arms for the quadriceps muscle. A pathway for the instantaneous center of rotation was chosen that gives realistic orientations of the femur relative to the tibia. Using the model, nonlinear force and moment equilibrium equations were solved at one degree increments for knee flexion angles from 0 (full extension) to 90 degrees, yielding patellar orientation, patellofemoral contact force and patellar ligament force and direction with respect to both the tibial insertion point and the tibiofemoral contact point. The computer-derived results from this two-dimensional model agree with results from more complex models developed previously from experimentally obtained data. Due to our model's simplicity, however, the operation of the patellar mechanism as a lever as well as a spacer is clearly illustrated. Specifically, the thickness of the patella was found to increase the effective moment arm significantly only at flexions below 35 degrees even though the actual moment arm exhibited an increase throughout the flexion range. Lengthening either the patella or the patellar ligament altered the force transmitted from the quadriceps to the patellar ligament, significantly increasing the effective moment arm at flexions greater than 25 degrees. We conclude that the levering action of the patella is an essential mechanism of knee joint operation at moderate to high flexion angles.

Biomechanical Phenomena↗
PubMed1986

[Arterial reconstructions spanning the knee joint].

Knee-joint crossing arterial repair is an alternative solution for patients whose extremities otherwise might have to be amputated. Indications are according to Fontaine for Stages III and IV. Specialised angiographic preparatory examination and knowledge of microsurgical techniques are required. Reference is made to peculiarities of surgical access routes, vascular substitute materials, and specific surgical techniques. The use of this approach to peripheral vascular repair appears to be justified against the background of international achievements and the authors' own results.

Angiography↗