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At least 325 records · Page 18Linked to original sources
PubMed1993

[Measuring intraosseous pressure of the patella: theoretical principles--animal experiment studies. Part I].

There are few reports in the literature about measurement of intraosseous venous pressure in bone. Necrosis of the femoral head was found to be related to higher intraosseous venous pressure. Values varied widely. Pain is thought to result when an individual critical intraosseous venous pressure is exceeded. From June 1986 to May 1987, 16 full-grown male rabbits were tested at the histological laboratory at the University of Innsbruck. The purpose of the study was to assess the intraosseous venous pressure of the patella and the revascularization and regeneration of cartilage following patella drilling. When animals were killed 3 months later, their patellas were filled with ink/gelatin. Histologically, there were numerous capillaries and new vessels in the drill-holes. The defect was filled with collagenous tissue. At the surface it differentiated into cartilage, similar to hyaline cartilage. Measurements of intraosseous venous pressure and phlebographies were also performed in four patellas in sheep at the research laboratory for experimental surgery in Davos, Switzerland. Intraosseous veins were filled with Biodur for further histological investigation.

Animals↗
PubMed1993

Shortening of patellar ligament and patella baja with improvement of quadriceps muscle strength after high tibial osteotomy.

One hundred and eight osteoarthritic knees that had high tibial osteotomy were examined, in the length of the patellar ligament, patellar height, and the strength of the quadriceps muscle. Patellar ligament shortening occurred until one year after surgery. Subsequently, shortening was not observed to be significant over a 10 year followup period. Using Insall-Salvati ratio, a majority of knees seemed to have lower patellae, because of the shortening of the patellar ligament. However, using patellotibial distance, 68 percent of patellae maintained the same height as preoperatively and 26 percent became patella baja. The strength of the quadriceps muscle increased postoperatively, reached the maximum at 2 years, and preserved the same strength over 10 years. Patellar ligament shortening and patella baja were probably thought to be caused by the biological adaptation of the extensor mechanism and the shrinking of the scar tissue in and around the postoperative patellar ligament.

Adaptation, Physiological↗
PubMed1993

[Course of recurrent dislocation of the patella, patellar syndrome without dislocation and femoropatellar osteoarthritis].

The frequency of recurrent dislocation of the patella is increased by the young age of onset, the presence of patella alta and permanent subluxation of the patella. The natural history of the patellar syndrome appears to be fairly favourable in everyday activities, but discomfort is often marked in the intermediate term in sports activities. Isolated femoropatellar osteoarthritis rarely causes major functional impairment of gait. Medial or lateral femorotibial osteoarthritis occurs secondarily. Painful cases often present with subchondral anomalies of the lateral patellar facet, lateral tibial osteophytosis and patella alta.

Adolescent↗
PubMed1993

Osteosarcoma of the patella. A case report.

A 34-year-old woman complained of pain and swelling in the left patella. Because of roentgenogram showed hardly any destruction of the patella, she was not initially treated for a bone tumor. The clinical course followed the initial symptoms of a respiratory disorder with pulmonary metastatic foci. A bone tumor was first suspected after aspiration cytology of a lung tumor mass. A left patellectomy was performed to relieve the pain and confirm the diagnosis. The pain was relieved by the operation, but respiratory failure set in and progressed rapidly. The patient died three days later. Histologic examination showed that the tumor tissue consisted of atypical cells, spindle to polygonal in shape. The marrow space of the patella was predominantly occupied by neoplastic cartilaginous tissue. The pathologic diagnosis was primary chondroblastic osteosarcoma of the patella.

Adult↗
PubMed1996

[Selective training of the vastus medialis muscle using electrical stimulator for chondromalacia patella].

Chondromalacia patella is closely related with subluxation and tilt of patella, as well as with muscular atrophy of quadriceps, especially in vastus medialis muscle. 364 cases of chondromalacia patella were treated with selective training of the vastus medialis muscle using electrical stimulator in our hospital. 211 cases were followed up after treatment from 6 months to 3 years. Among them excellent and good results were seen in 130 cases (62%), fair results were seen in 69 cases (33%) and no change was seen in 12 cases (5%). Significant reduction of CA (P < 0.01) and LPA (P < 0.001) were observed in all these patients in comparison with their primary angle. We believe that the selective training of the vastus medialis muscle using electrical stimulator is one of the effective methods for the treatment of chondromalacia patella.

Adult↗
PubMedDate not supplied

Patellar tendon-to-patella ratio in children.

Patellofemoral problems are common in skeletally immature patients. In the evaluation of this condition, it is important to determine the position of the patella on lateral radiographs. There are no normal values to determine this ratio (patellar tendon-to-patella ratio). In this study, 225 anteroposterior (AP) and lateral radiographs of skeletally immature knees were examined and bone ages determined. The patellar tendon-to-patella ratio was then calculated for each age group until skeletal maturity. These ratios allow a more accurate assessment of patella alta in the pediatric population, assisting in diagnosis and surgical planning.

Adolescent↗
PubMed2005

Locked lateral patella dislocation with generalized ligamentous laxity after arthroscopic lateral release of the knee.

We describe the case of a 14-year-old boy with patellar instability on both sides resulting from ligamentous hyperlaxity and dysplasia of the lateral femoral condyle who had previously undergone an arthroscopic lateral release as well as plication of the medial capsule. The patient presented to our clinic 2 years after surgery with a locked lateral patella dislocation on the left side. The surgical correction involved a substantial open lateral release including an excision of the scar tissue and stabilization of the patella in the patellofemoral groove by tibial tubercle medialization and plication of the medial capsule. Six months after surgery, the patient achieved a Lysholm score of 90 points and clinical examination indicated a stable knee with a centralized patella without any evidence of subluxation or dislocation. Open lateral release with partial resection of the lateral retinaculum, medial reconstruction, and tibial tubercle osteotomy was the procedure of choice in this patient with habitual patella dislocation caused by generalized ligamentous laxity.

Adolescent↗
PubMed1997

Patella position and biomechanical properties of the patellar tendon 1 year after removal of its central third.

OBJECTIVE: The aim of this study was to investigate how the removal of a patellar tendon graft for cruciate ligament reconstruction influences the mechanical properties of the remaining patellar tendon and the position of the patella at the knee joint. DESIGN: The experimental model of this in vivo study was the anterior cruciate ligament reconstruction in sheep. BACKGROUND: While the efficacy of a patellar tendon third as a ligament replacement has been extensively investigated, the consequences for the function of the remaining tendon and patella position remain unclear. METHODS: The central third of the patellar tendon from the right knees of 10 animals was removed for cruciate ligament replacement. One year postoperatively, the position of the patella within the joint and the stiffness and modulus of elasticity of the remaining tendon were compared with the non-operated contralateral controls. RESULTS: The patella position did not change in the operated knee joints in comparison with the controls. The cross-sectional area of the operated patellar tendon increased significantly by scar tissue formation at the defect site. CONCLUSION: Although the inferior mechanical properties of the scar tissue reduced the modulus of, elasticity of the tendon, the increase in cross-sectional area allowed it to develop a structural stiffness similar to the control tendons. RELEVANCE: The central third of the patellar tendon is often used for ligament replacement. Resulting biomechanical and structural changes in the remaining patellar tendon have not been previously reported using an in vivo animal model. The recovery of the biomechanical properties of the partially resected tendons allows for continued function.

Journal Article↗
PubMed2000

Computer-assisted decision analysis in orthopedics: resurfacing the patella in total knee arthroplasty as an example.

The purpose of the present study was to illustrate the use of computer-assisted decision analysis in making decisions in the field of orthopaedic surgery, using the choice between resurfacing and not resurfacing the patella in total knee arthroplasty as an example. We used a decision analysis technique based on probability theory and on Bayesian logic, with the help of an especially developed computer software. The process involves building a decision tree, searching for probabilities and utilities in the literature, folding back the tree to compute the baseline result, and running sensitivity analyses. Our literature search provided 26 useful articles, only 3 of which were randomized controlled trials. In the baseline analysis, both options were rated similarly, with resurfacing the patella faring slightly better. Sensitivity analyses revealed that not resurfacing becomes the procedure of choice if the probability of postoperative anterior knee pain with an unresurfaced patella falls below 14%, or if the probability of having pain with a resurfaced patella rises above 8% or if the utility of patellar implant failure falls below 80% of the utility of a perfect health state. Computer-assisted decision analysis is a promising, evidence-based tool to assist clinical decision making in orthopaedic surgery. However, its validity is limited by the poor quality of data found in the orthopaedic literature, especially the scarcity of randomized controlled trials.

Arthroplasty, Replacement, Knee↗
PubMed2006

MRI of osteochondral defects of the lateral femoral condyle: incidence and pattern of injury after transient lateral dislocation of the patella.

OBJECTIVE: The typical bone bruise pattern involving the anterolateral femoral condyle and inferomedial patella after transient lateral dislocation of the patella is a well-described MRI finding. In our study, however, we sought to determine the incidence and location of lateral femoral condyle osteochondral injuries after transient lateral dislocation of the patella. CONCLUSION: Osteochondral defects of the lateral femoral condyle are a common sequela after transient lateral patellar dislocation. A significant number of osteochondral injuries involve the midlateral weight-bearing portion of the lateral femoral condyle and are more posterior than would be expected after transient dislocation of the patella.

Adolescent↗
PubMed1996

[Nail-patella syndrome].

The nail-patella syndrome is an autosomal dominant trait characterized by abnormalities of the nails, patella and radial head, iliac crest and, in some cases, nephropathy. The genetic defect is localized on chromosome 9q34.1. The clinical features in affected individuals vary greatly. The nephropathy may progress to end-stage renal failure, leading to decreased life expectancy. We report a woman with bilateral hypoplastic thumbnails, who also had aplasia of both patellae and subluxation of the left elbow joint with hypoplasia of the radial head. The mother and the sister of the patient had similar changes and also suffered from nephropathy.

Aged↗
PubMed1999

Localization of a gene for familial patella aplasia-hypoplasia (PTLAH) to chromosome 17q21-22.

Patella aplasia-hypoplasia (PTLAH) is a rare genetic defect characterized by congenital absence or marked reduction of the patella. PTLAH can occur either as an isolated defect or in association with other malformations, and it characteristically occurs in the nail-patella syndrome and in some chromosome imbalances. We report the first evidence of linkage for isolated PTLAH in an extended Venezuelan family. After exclusion of the candidate chromosome regions where disorders associated with PTLAH have been mapped, a genomewide scan was performed that supported mapping of the disease locus within a region of 12 cM on chromosome 17q22. Two marker loci (D17S787 and D17S1604) typed from this region gave maximum LOD scores >3. Accordingly, multipoint analysis gave a maximum LOD score of 3.39, with a most likely location for the disease gene between D17S787 and D17S1604. Sequencing of the noggin gene, a candidate mapping between these markers, failed to reveal any mutation in affected subjects.

Adolescent↗
PubMed2002

Meier-Gorlin syndrome (ear-patella-short stature syndrome) in an Italian patient: clinical evaluation and analysis of possible candidate genes.

We report on an Italian boy with the Meier-Gorlin syndrome (ear-patella-short stature syndrome). This rare autosomal recessive disorder comprises the triad of microtia, absent patellae, and growth retardation with prenatal onset. The patient had also an acute torsion of his left spermatic cord, a condition related to a congenital defect of the tunica vaginalis. Because this syndrome had been suggested as the human equivalent of the short ear mouse [Lacombe et al., 1994: Ann. Genet. 37:184-191], a mutation analysis of the BMP5 gene was performed and found normal. The LMX1B and the SHOX genes were also evaluated considering the absent patellae and short stature, respectively, and were found normal as well.

Abnormalities, Multiple↗
PubMed2001

Evaluation of chondromalacia of the patella with axial inversion recovery-fast spin-echo imaging.

The purpose of our study was to assess the accuracy of inversion recovery-fast spin-echo (IR-FSE) imaging for the evaluation of chondromalacia of the patella. Eighty-six patients were included, they underwent magnetic resonance (MR) examination and subsequent knee arthroscopy. Medial and lateral facets of the patella were evaluated separately. Axial images were obtained by using IR-FSE (TR/TE/TI = 3000/25/150 msec; echo train length, 8; 4-mm thickness; 12-cm field of view; 512 x 256 matrix; two, number of excitations) with a 1.5-T MR machine. MR interpretation of chondromalacia was made on the basis of the arthroscopic grading system. Of a total of 172 facets graded, arthroscopy revealed chondromalacia in 14 facets with various grades (G0, 158; G1, 1; G2, 3; G3, 6; G4, 4). Sensitivity, specificity, and accuracy in the chondromalacia grades were 57.1%, 93.0%, and 90.1%, respectively. There was one false-negative case (G4) and 11 false-positive cases (G1, eight; G2, two; G3, one). Sensitivity and specificity corrected by one grade difference were improved to 85.7% and 98.1%, respectively. When cartilage changes were grouped into early (corresponding to grade 1 and 2) and advanced (grade 3 and 4) diseases, sensitivity and specificity of the early and advanced diseases were 75% and 94% and 80% and 99%, respectively. IR-FSE imaging of the knee revealed high specificity but low sensitivity for the evaluation of chondromalacia of the patella.

Adolescent↗
PubMed1990

The three-dimensional tracking pattern of the human patella.

A study was undertaken to provide data on the three-dimensional tracking pattern of the patella, relative to the femur, in human knee-joint specimens. For this purpose, a highly accurate roentgen stereophotogrammetric analysis (RSA) method was applied. The three-dimensional motion patterns of the tibia and the patella were measured and represented in terms of three translations and three rotations each, during knee flexion in neutral (unloaded), endorotated, and exorotated pathways. We found that the patella displays complex but consistent three-dimensional motion patterns during flexion, which include flexion rotation, medial rotation, wavering tilt, and a lateral shift relative to the femur. The motion patterns are very much affected by tibial rotations accompanying flexion.

Humans↗
PubMed1979

Patella displacement and osteoarthrosis of the knee joint in mice.

Surgical stabilisation of the normally medially--subluxing patella of STR/ORT male mice, prevented the normal development of osteoarthrosis in the medial compartment of the femoro-tibial joint. Surgically produced medial dislocation of the patella in non-arthrosis-prone male CBA/ORT mice often gave rise to osteoarthrosis of the medial condyles. This, with further evidence from previous studies, strongly indicates that the high incidence of degenerative joint disease in male STR/ORT mice occurs because of a tendency of the patella to dislocate medially due to some unknown cause.

Animals↗
PubMed1995

[Treatment of posterior cruciate ligament rupture and recent knee dislocations by olecranisation of the patella without surgical repair].

Olecranisation of the patella was described and first used by Grammont (1984) to maintain reduction of the knee joint after posterior cruciate repair and reconstruction. Since 1985 we used this technique in 18 acute posterior ruptures and knee dislocations which did not undergo surgery. Knee laxity is assessed under general anaesthesia with radiographic control. A 4 or 5 mm. Steinmann pin is introduced medially at the top of the patella and drilled vertically through the bone to continue behind the patella tendon. After reduction of the posterior drawer, the pin is passed into the anterior part of the tibia. Full mobility between 0 degrees and 90 degrees is maintained. Physiotherapy started immediately and early weight bearing is allowed with a posterior splint. Olecranisation prevents posterior subluxation of the tibia and gives an anterior tibial subluxation force which is minor in flexion but major in extension. We followed up our patients for 1 to 8 years. The latest testing with radiographs demonstrate posterior drawer but all patients report good results. Early physiotherapy avoids stiffness, amyotrophy, and reflex sympathetic dystrophy. Olecranisation appears to give similar results more quickly and with fewer complications than P. C. L. surgery.

Acute Disease↗
PubMed1992

Development of functionally distinct fibrocartilages at two sites in the quadriceps tendon of the rat: the suprapatella and the attachment to the patella.

This paper describes the post-natal development of two fibrocartilages in the quadriceps tendon of the rat. The compression-resisting fibrocartilage of the suprapatella was derived from a cell population present in neonates and positioned on the deep surface of the tendon of vastus intermedius. The cells secreted a metachromatic, coarsely fibrous extracellular matrix that was rich in chondroitin sulphate but lacked keratan sulphate or type II collagen. The cells themselves accumulated large quantities of vimentin. The adult form of the suprapatella was attained 8 weeks after birth. The fibrocartilage of the attachment zone of the quadriceps tendon to the patella was formed in a different manner. In animals up to 4 weeks of age, the quadriceps tendon inserted directly into the cartilage model of the patella. When later this was resorbed, and replaced by bone, the cartilage at the attachment zone remained, along with that of the articular surface of the patella. Attachment-zone fibrocartilage was therefore rich in type II collagen, unlike that of the suprapatella. Thus two functionally different fibrocartilages have been shown to have different origins, even when separated by only a short distance within the same tendon. The compositional differences between attachment-zone and compressive region fibrocartilages are also due to their different origins.

Animals↗