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At least 595 records · Page 33Linked to original sources

Localized pigmented villonodular synovitis presenting as recurrent dislocation of the patella.

A 31-year-old woman presented with a 1-year history of recurrent dislocation of the patella. On examination, she was found to have a mass at the medial patellofemoral joint line. Arthroscopy showed this to be a vascular synovial tumor extending into the medial patellofemoral joint and causing lateral deviation of the patella. The mass was resected with resolution of her symptoms and histologic examination showed this to be pigmented villonodular synovitis. There are an increasing number of case reports of these lesions causing varying mechanical symptoms in the knee and they should be considered as a differential diagnosis.

Adult↗

Arthroscopic treatment of soft-tissue impingement under the patella after total knee arthroplasty.

There has been an increased number of reports of complicated diseases of the patellofemoral joints after total knee arthroplasty (TKA). We treated soft-tissue impingement under the patella after TKA by arthroscopic surgery and investigated the findings and efficacy of the treatment. Six patients and 8 knees that showed soft-tissue impingement of patellofemoral joints after TKA were treated by arthroscopic surgery. We classified the patients with soft-tissue impingement under the patella into 3 groups: (I) patellar clunk syndrome, the isolated fibrous nodule located in the suprapatellar lesion without the other fibrous tissues causing the impingement (n = 2); (II) impinging hypertrophic synovitis, generalized hypertrophic synovitis with no fibrous nodule (n = 4); and (III) the combination of types I and II, the suprapatellar fibrous nodule with generalized hypertrophic synovitis (n = 2). Therapeutic efficacy was in type I, 2 were good to excellent; in type II, 3 were fair and 1 was poor; and in type III, 2 were fair. Better results were obtained in type I (a patellar clunk syndrome) than in type II (impingement synovitis).

Arthralgia↗

The effect of patella preparation for total knee arthroplasty on patellar strain: a comparison of resurfacing versus inset implants.

This study was conceived to quantify variables in surgical technique that may lead to patellar fracture after total knee arthroplasty. Anterior surface strain on load-bearing cadaveric patellae was measured before and after patellar resurfacing or inset prosthesis placement. Variables studied were i) the type of prosthesis (resurfacing vs inset), ii) the depth of reaming or osteotomy during surface preparation, and iii) the overall thickness of the polyethylene/patella composite after implantation. Comparison of measured patellar surface strain patterns for the different prosthesis styles, which were implanted at varying depths, provided statistically significant data from which the following clinically relevant conclusions can be made: i) Patellar resurfacing is superior to inset prosthesis placement when comparing postoperative patellar strain (22% vs 28% increase in strain compared with preoperative values). ii) Osteotomy for patellar resurfacing is more tolerant to error by excess cutting than is reaming for inset prosthesis placement (25% vs 42% increase in strain with a 2-mm error). iii) If the ideal depth of cut or reaming is surpassed, attempts to re-create the original patellar thickness by using a thicker prosthesis are mechanically detrimental. Key words: patella, strain, resurfacing, complications.

Aged↗

[Patella fragmentation in cerebral palsy].

In 16 patients with cerebral palsy 23 painful fragmentations at the lower pole of the patella were observed and surgically removed. In all cases pain was relieved immediately. Patellar fragmentations usually appeared in children between 12 and 16 years, in males twice as often in females. Patella alta was seen in all cases. All patients were walkers, however, 4 with hand supports only. In 14 of the 16 children there was knee flexion deformity during gait of 20-60 degrees. The cause of fragmentation is regarded to be overload of the quadriceps muscle in a juvenile bone condition, and is related to the "jumper's knee" due to fatigue. In 9 of the 16 patients an achilles tendon lengthening had been performed several years before, without overcorrection. All patients were of reasonable intelligence.

Adolescent↗

[The distribution of cartilage degeneration of the human patella in relation to individual subchondral mineralization].

According to Pauwels and Kummer the distribution of the subchondral mineralisation can be taken as a measure of the long-term mechanical loading in the joints. Based on a previous study concerning the density distribution of the subchondral bone of the human patella, these results were compared in the following paper with the macroscopically visible cartilage lesions. Degenerative changes on the lateral facet of the patella coincide with regions of high bone mineralisation, those on the "odd facet" on the other hand with areas of low subchondral density. The cartilage lesions on the lateral facet are seen as being due to high and constant mechanical stress, those on the "odd facet" to short infrequent stress-peaks.

Absorptiometry, Photon↗

[Intramedullary patella pressure measurement dependent on the functional position of the knee joint].

Degenerative alterations of the patello-femoral joint are often painful and cause an increase of intramedullary pressure. The intraspongious pressure of the patella is measured with a cannula after lateral drilling. Patients with chondromalacia or osteoarthrosis have an increased intramedullary pressure compared with normal patients. The degree of flexion of the knee-joint correlates with the intramedullary pressure. More flexion causes an increase of pressure as well in normal patella as in chondromalacia or in osteoarthrosis.

Adult↗

[Normal anatomy of the patella in advanced age].

The form of the kneecap is determined by heredity. It is modified by the various tissue-modeling, functional-mechanical forces acting on it in the course of life. The individual "face" of a patella is the result of these two factors, including any malformations or pathologic changes of the tissue (in particular the cartilage). Numerous measurements were made on patellae of elderly subjects - obtained from autopsies and without any apparent macroscopic changes apart from those which were age-related, such as cartilage color - in order to map the ideal patellar shape, which would appear to be unsusceptible (or less susceptible) to pathologic disturbances.

Aged↗

[2 new methods for determination of the height of patella].

A short review of the literature on various methods of determining the height of the patella in the sagittal plane is given. These methods are critically appraised. Two new measuring techniques based on other well-known ones are presented which have a number of advantages over those currently used. The accuracy of the two methods is about the same. The new patellar height angle is recommended. Both methods use the distal end of the femur as a reference and depend on the degree of bending of the knee on lateral films. Since, for technical reasons, a standardized lateral view, e.g., with 30 degrees flexion, is not feasible, both methods require a conversion table which indicates the knee-bending angle to within 5 degrees. In order to differentiate better between a knee cap at normal height and a patellar dystopia an intermediate or transition zone is stipulated. Measuring of the height of the patella requires more knowledge and experience than is generally realized. There is still no really convincing and absolutely reliable measuring method.

Humans↗

[The small patella syndrome. A combination of knee and pelvic dysplasia].

In 1979, using the name "small patella syndrome", Scott and Taor described a family in which hypoplasia or aplasia of the patella was inherited by autosomal dominant transmission. Hip dysplasias and pelvic changes accompanying the patellar changes have also been observed in some cases. On the basis of three personal observations this dysplasia syndrome is described in more detail and compared with the other syndromes involving the kneecap and pelvis. One case was discovered as a result of a femoropatellar pain syndrome, a second because of slight functional disturbances. The third case was a chance finding. Although, in two of the cases, several affections of the locomotor apparatus were found in the patients' families, it could not be confirmed that the syndrome was hereditary.

Child↗

[Posterior defects of the patella on CT arthrograms. Detection and differential diagnosis].

Changes of the posterior bony and cartilaginous surfaces of the patella as seen on CT arthrograms are described in the case of bipartite patellae, fractures and ossification defects. Contrary to present opinion, cartilaginous lesions are frequently seen on CT arthrograms. This is also true for discreet and partial ossification defects which are not visible on conventional x-rays and are described here for the first time. The aetiology, morphogenesis and clinical examples are discussed.

Adolescent↗

[Experimental patello-femoral contactprint measurements. 2. Report: sagittal osteotomy of the patella according to Morscher (author's transl)].

The recommended treatment method for chondropathy from Morscher 1978 using a sagittal patellaosteotomy was tested experimentally with contact area measurements with the erasing method on 11 corpse knees of the types II, II/III and III. Measurements were made in the bending region up to 90 degrees, and in isolated positions up to 140 degrees. The measurements showed a clear decrease in the contact area of the medial side of the lateral facet, and occassional displacement of contact whereby loses on the paramedial segment were compensated for by early loading on the border segment. Thus unphysiological loading of the medial facet occurred, from which chondromalasys could develop. Only three patellas had an increased contact area during inflexions up to 90 degrees, and then only because the central cartilage area, which usually undergoes the greatest loses, was already incongruent. Since during a complete knee bending the retropatella cartilage has almost 100% contact and that due to the medial cartilage ridge a considerably smaller incongruence is present as can be expected from the bone crosssection of the patella, we cannot expect any contact increase through an osteotomy.

Biomechanical Phenomena↗

[Chondropathia patellae].

Chondropathia patellae on a constitutional basis, in the narrow sense of the term, is predominantly responsible for producing the painful or irritated knee in juveniles and adolescents, with an incidence peak around the 20th year of life. The traumatic form associated with signs will often produce the same disorders of the patellar gliding path and of the gliding areas, such as the hyperpression and lateralisation syndrome, as well as habitual luxation. Clinically, degenerative articular damage may temporarily exacerbate into a kind of synovitis "chondsrodetritica", especially on overstraining and after microtraumas. On reviewing the case history, the retropatellar pain after prolonged seating and on walking downhill, is particularly characteristic; this pain can also radiate in medial direction. It is also often reported that the knee tends to "give way" suddenly, and to "interlock" or "become entangled". The leading clinical symptom is, besides a feeling of roughness, the "characteristic" pain caused by the gliding pressure of the patella. Conservative treatment, consisting of physiotherapy, isometric exercises of the quadriceps femoris muscle preceded or if permissible followed by heat and massage treatment, and therapy directed at protecting the cartilage - while avoiding cortisone preparations - should be discontinued if the success of treatment does not last significantly longer than the application. Satisfactory results can be obtained with the three basic operations such as proximolateral relief operation (longitudinal splitting of the retinacula), distal relief surgery (lifting of the tuberositas) and smoothening or more vertical excision of the focus of cartilaginification, in conjunction with further surgical interventions.

Adrenal Cortex Hormones↗

[Plasty for operative treatment of slipping patella-technique and results (author's transl)].

We describe a plasty for stabilization of the slipping Patella. The elimination of the Anti-Bandi-Effect and the simultaneous discision of the distal insertion of the Musculus vastus lateralis and the lateral retinaculum apparatus is of importance. The results 5 months till 5 years after intervention are excellent. By none of the 59 knee joints occurred a reluxation even all 46 patients have taken up their work and their sports. Except 1 all patients are subjectively satisfied. We can recommand this technique for treatment of slipping Patella, if not a deformity outside of the patellofemoral joint caused this affection. This operation can also be performed on adolescents with open proximal tibial epiphyseal cartilage.

Adolescent↗

[Modification of sagittal osteotomy of the patella as treatment of excentric chondromalacia or retropatellar arthrosis. Preliminary communication (author's transl)].

The author presents a modification of Morscher's sagittal osteotomy of the patella especially for the treatment of excentric chondromalacia. Congruity of the joint spaces in this modification is achieved through removal of an anteriorly based bone wedge from the patella after sagittal wedge osteotomy allowing the lifting of one or the other patellar facet. This osteotomy is indicated in all cases of unilateral chondromalacia or arthrosis with narrowing of the two joint spaces viewed on tangential patello-femoral X-rays. Following the ideas of Pauwels and Maquet, restoration of a wide joint space and reduction of local excessive stress result in reparative mechanisms of the cartilage involved. The to date preliminary clinical results in 5 cases (1 year max. follow-up) are encouraging.

Adult↗

[Plain film appearances of chondropathia patellae. Morphological changes after surgical treatment (author's transl)].

The localised patella defects in our material of 90 patients were largely unchanged up to nine months after surgical treatment. Persistence of soft tissue swelling round the knee correlates with continuing pain. In some cases there has been remineralisation of the patella, which can be regarded as a stage in healing. Unchanged or deteriorating radiological findings may be associated with clinical improvement or deterioration.

Humans↗

Osteonecrosis of the patella in patients with nontraumatic osteonecrosis of the femoral head: MRI findings in 60 patients.

We examined both knees in 60 patients with nontraumatic osteonecrosis of the femoral head with three-dimensional MRI. We found osteonecrosis of the patella in 9 patients (10 knees) and osteonecrosis of the femoral or tibial condyles/metaphyses in 35 patients (61 knees). In the patella, the necrosis was located in the proximal half and tended to develop in patients with other necrotic lesions in the knee.

Adolescent↗

Vastus lateralis fibrosis in habitual patella dislocation: an MRI study in 28 patients.

We studied 28 patients with habitual or recurrent dislocation of the patella with MRI of both thighs. Apart from the 2 patients whose dislocation could be related to trauma, we found signs of fibrosis of the vastus lateralis muscle in all the affected limbs of the 26 patients with an insidious onset of dislocation. This was seen as low signal intensity cords in the muscles in the T2 weighted image. Muscle degeneration was seen as high intensity signals in the T1 weighted image. In patients with unilateral disease, the vastus lateralis muscle of the affected side was hypotrophic, compared to that of the normal side. 2 patients underwent a biopsy of the affected muscle area. Histopathological examination revealed inflammatory cell infiltration, fibrosis, and muscle fiber degeneration. Fibrosis of the vastus lateralis muscle appears to be common in patients with habitual patella dislocation in our population, and may be the cause of the dislocation. Since release of such a contracture may be of value, MRI study of the thigh muscles is helpful in the evaluation of patients with this disorder.

Adolescent↗

LMX1B transactivation and expression in nail-patella syndrome.

Lmx1b, a member of the LIM homeodomain protein family, is essential for the specification of dorsal limb fates at the zeugopodal and autopodal level in vertebrates. We and others have shown that a skeletal dysplasia, nail-patella syndrome (NPS), results from mutations in LMX1B. While it is a unique mesenchymal determinant of dorsal limb patterning during vertebrate development, the mechanism by which LMX1B mutations generate the NPS phenotype has not been addressed at a transcriptional level or correlated with its spatial pattern of gene expression. In this study, in situ hybridizations of Lmx1b on murine limb sections reveal strong expression in dorsal mesenchymal tissues (precursors of muscle, tendons, joints and patella) and, interestingly, also in anterior structures of the limb, explaining the anterior to posterior gradient of joint and nail dysplasia observed in NPS patients. Transfection studies showed that both the LIM domain-interacting protein, LDB1, and the helix-loop-helix protein, E47/shPan1, can regulate LMX1B action. While co--transfections of E47/shPan1 with LMX1B result in a synergistic effect on reporter activity, LDB1 down-regulated LMX1B-mediated transactivation irrespective of E47/shPan1. Mutant LMX1B proteins containing human mutations affecting each of the helices or the N-terminal arm of the homeodomain abolished transactivation, while LIM B and truncation mutations retained residual activity. These mutations fail to act in a dominant-negative manner on wild-type LMX1B in mixing studies, thereby supporting haploinsufficiency as the mechanism underlying NPS pathogenesis.

Animals↗