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At least 307 records · Page 17Linked to original sources
PubMed1999

Management of double-layered patellae by compression screw fixation.

Tripartite patella is a form of double-layered patella in which the anterior layer is bipartite. It was first described by Büttner in 1925 (1). More recently, an association with multiple epiphyseal dysplasia has been described (2,3). In this article, we describe a case of symptomatic tripartite patella in a 13-year-old child who was subsequently found to have features of multiple epiphyseal dysplasia. Her patellae had an abnormal excursion with a click and a visible jump in the longitudinal line of movement, but no lateral instability. We present a surgical solution not previously described by fusion of the two main components and report an excellent result.

Adolescent↗
PubMed2001

Effect of femoral component designs on the contact and tracking characteristics of the unresurfaced patella in total knee arthroplasty.

OBJECTIVES: To determine the effect of 5 different femoral components used in total knee arthroplasty (TKA) on the contact area and tracking characteristics of the nonresurfaced patella and to identify any design features that might adversely affect these characteristics. DESIGN: An in-vitro study. SETTING: The biomechanics laboratory, Department of Mechanical Engineering, McGill University, Montreal. SPECIMENS: Six fresh-frozen cadaveric knee-joint specimens. INTERVENTIONS: An unconstrained quadriceps simulator was used to apply the conditions of static lifting to the specimens first in their normal state and then sequentially implanted with femoral and tibial components of various designs (Miller/Galante II, Anatomic Modular Knee [AMK] System, Whiteside Ortholoc Modular, press-fit condylar and Insall-Burstein II). OUTCOME MEASURES: Patellar 3-dimensional tracking characteristics, determined by using a 6 degrees-of-freedom electromechanical goniometer attached directly to the patella, and patellar contact pressure measurements, obtained using low-range Fuji Prescale film. RESULTS: Articulation of the normal patella on a prosthetic femoral component resulted in alterations in the normal patellofemoral contact and tracking characteristics. The exact departure depended on the design of the prosthetic trochlea. Although all of the selected prostheses demonstrated satisfactory contact characteristics near extension, marked alterations occurred at higher flexion angles. With 90 degrees or more of flexion, there was incompatibility between the geometries of the prosthetic notch of 2 femoral designs (AMK and PFC) and the normal knee. CONCLUSION: The design of the prosthetic femoral component must be taken into account when determining whether or not to resurface the patella at the time of TKA.

Adult↗
PubMed1975

Late results of transfer of the tibial tubercle for recurrent dislocation of the patella.

The authors wished to determine the late results of the Hauser operation, with special reference to the development of osteoarthritis. Predisposing factors associated with recurrent dislocation of the patella were also investigated. Thirty-five patients with forty-four surgically treated knees attended for review, ten to twenty-five (average sixteen) years after operation. Two patients had subsequently undergone excision of the patella. Ten patients gave a family history of recurrent dislocation of the patella and seven patients showed generalised joint laxity. Pain was present in eight knees before operation and was present in thirty-three knees (75 per cent) at the time of review. Patella crepitus was present in thirty-seven out of forty-two knees (88 per cent) at review. Osteoarthritis was present in thirty out of forty-two knees (70 per cent). The incidence increases with time since operation and the present age of the patient. It is concluded that the Hauser operation prevents further dislocation but does not prevent the development of osteoarthritis. It is possible that a simple soft-tissue operation which effectively prevents dislocation might achieve the same results.

Adolescent↗
PubMed1999

[An experimental study of viscoelastic properties of articular-cartilage of patella].

OBJECTIVE: To study the viscoelastic properties of human articular cartilages of patella in 8 cadavers, which were obtained from patients ranged in age from nineteen to fifty-one years old and died of acute head injury. METHODS: The creep and stress relaxation of articular cartilage of patella were abserved in the condition of articular cartilage loaded of 500 Pa, just as the physiological load of articular cartilage of patella in keeping human body standing position with the knee joint flexed 30 degrees, during the experiment. The deformation-time curve under certain load, the load-time curve under certain deformity and related data were obtained. RESULTS: Creep and stress relaxation showed that obvious changes occured in the first 10-15 minutes during the whole process. CONCLUSIONS: The data and curve will not only be helpful to understand the pathogenesis of chondromalacia, but also propose a feasible method to study it from biomechanical view, meanwhile provide reference data for designing the prosthesis of patella and material choosing.

Adult↗
PubMed2001

[Preliminary investigation on the pathogeny, diagnosis and treatment of chondromalacia patella].

This paper presents the preliminary investigation on chondromalacia patella at our department in recent years. A random cluster sampling survey covering 2743 normal persons was carried out. The prevalence rate is 36.2%. It was found that, applying transmission electron microscope and immunohistochemical methods on to cartilage tissues of the abnormal region, articular cartilage necrosis was in direct proportion with the abnormal pressure, while the restoration capability of local chondrocytes was in inverse proportion with pathological changes and the pressure. The chondromalacia patella was produced by repeated abnormal stress acting on the cartilage. The stress derived from the uncongruency and the decreasing in the contact area of patellofemoral joint when the subluxation or tilt of patellae was caused by the abnormal anatomical and biomechanical relationship. The initial lesion was at the matrix of cartilage, the collagen network was disrupted, then proteoglycan was lost. The microenvironment of chondrocytes was changed with degradation of matrix. So the chondrocytes became degenerative and necrosis from superficial to deep layer, then feed back the matrix again. Finally, the total cartilage layer might disappear, and the bone under cartilage might proliferate. At late stage, the cartilage was completely destroyed and had no self-restorative ability. Therefore, early diagnosis and treatment are necessary. It is highly suggested axis radiograph of the knee with the tibiae tuberositas localization are helpful to early diagnosis. Furthermore, JKY-Muscle Rehabilitation Instrument is invented for non-operative therapy. It enhances muscle power by selective training of the vastus medialis muscle using electrical stimulator to relieve pain and correct subluxation of patella with 90% efficiency (63% of excellent-effective rate). In late stage, patellofemoral replacement is recommended. The excellent-effective rate is 86.3%.

Arthroplasty, Replacement, Knee↗
PubMed1990

[A self-constructed device for reduction and stabilization of multi-fragmented fractures of the patella. Technical data and analysis of clinical material].

The author has presented the construction and use of his own device for reduction and stabilisation of multi-fragment fractures of the patella ("patella-clamp"). The device was examined in action first on cadavers and then introduced to clinical use. The use of the "patella-clamp" made possible to obtain better results in surgical treatment of multi-fragment fractures of the patella.

Adult↗
PubMed1992

Knee extensor mechanics after subtotal excision of the patella.

Two sets of six fresh frozen autopsy specimens were used to test the quadriceps force requirements for knee extension after sequential distal-to-proximal and proximal-to-distal excisions of the patella. The quadriceps force as a function of knee flexion angle was recorded for varying amounts of excision and compared with the results for total patellectomy. Excision of the proximal one half or less resulted in lower force requirements when compared with total patellectomy. The effects of removal of the proximal three-fourths length of patella were inconsistent and actually increased the force requirements in three knees. The effects of distal to proximal excisions indicate a biomechanical advantage to maintaining a fragment equal to at least three fourths the length of the proximal patella. Retaining a fragment of adequate size preserves at least some of the mechanical advantage provided by the intact patella.

Aged↗
PubMed2005

Discriminating sex in South African blacks using patella dimensions.

For many years, sex determination has been carried out on skeletal remains to identify individuals in forensic cases and to assess populations in archaeological cases. Since it has been shown that not all bones are found in a forensic case, discriminant function equations should be derived for all bones of the body to assist in sex determination. Numerous studies have shown the usefulness of bones of the lower extremity (e.g. femur, tibia) in sex determination using discriminant function analysis, but the use of patella measurements has not been extensively investigated for this purpose. It is therefore the aim of this study to derive discriminant function equations for sex determination from measurements of the patella of South African blacks as represented in the Raymond A. Dart Collection of Human Skeletons. A total sample of 120 (60 male, 60 female) patellae were measured using six measurements. The Statistical Product and Service Solutions (SPSS) program was used to derive the equations. Stepwise and direct analyses were performed with the highest rate of classification of 85% thereby making the patella useful for sex determination. Thus, the proposed equations derived from this study should be used with caution and only on the South African black population group.

Black People↗
PubMedDate not supplied

Surgical management of congenital and habitual dislocation of the patella.

Twelve patients with congenital dislocation of the patella (CDP) and 23 patients with habitual dislocation of the patella (HDP) were followed for 2-15 years after surgical stabilization of the patella. The underlying pathology in both conditions was contracture of the quadriceps mechanism, which was more severe in CDP. Surgical stabilization in most cases included an extensive lateral release, medial plication, and transfer of the lateral half of the patella tendon. Lengthening of the rectus femoris tendon was required in many cases. With appropriate operative procedures, satisfactory results were achieved in 36 of the 41 knees (87.8%).

Activities of Daily Living↗
PubMed1989

[Initial dislocation of the patella; which treatment?].

Twenty patients, victims of a first luxation of the patella, were the object of a retrospective study. They were all subjected to arthroscopic examination during which, in 7 of the patients, the liquid injected under pressure massively escaped into the subcutaneous layer of the medial side of the knee. The patients were divided into 2 groups according to the integrity of the capsule of their knees. Group I consisted of 7 patients, group II of 13 patients. The treatments, the majority of which were conservative, were quite varied, but the post-traumatic functional recuperation was much slower and more variable for the group I patients. These patients presented more significant tissue lesions which certainly contributed to the functional prognosis of the traumatized joint. Seventy two percent of the patients, equally distributed between the 2 groups, presented trochleo-patellar dysplasia. With the exception of age, different clinical parameters (sex, circumstances of the accident, clinical examination) and radiological criteria (external displacement of the patella, detached bony fragment at the interior border of the patella, value of the patellar and trochlear angles, patella alta) did not permit a distinction between the two groups. Because of our results and those in the existing literature we recommend arthroscopy, which is the only examination capable of establishing a complete picture of the lesions and which, in addition, permits rising of the joint and sometimes allows extraction of free osteo-cartilaginous fragments. The younger patients may then benefit from immediate functional reeducation. For older patients, where the tissue lesions are more important, conservative treatment is associated with a slower and sometimes variable functional recuperation. It remains to be determined, whether surgical treatment, adapted to each case, would permit us to obtain better results more rapidly.

Adolescent↗
PubMed1989

Lateral facet syndrome of the patella. Lateral restraint analysis and use of lateral resection.

Thirty-eight knees in 34 patients with an average age of 22 years were diagnosed as having lateral facet syndrome (LFS), a painful compressive arthropathy of the lateral facet of the patella. This diagnosis was based on the physical findings of tenderness at the lateral patellofemoral joint line, tenderness over the vastus lateralis obliquus (VLO) tendon just above the patella, a positive medial apprehension test, and marked resistance to medial patellar displacement with the knee flexed 30 degrees. The most common complaints were patellar pain with activity, pain with prolonged knee flexion, intermittent knee swelling, and giving way. At surgery, the VLO, the lateral retinaculum (LR), and the anterior fibers of the iliotibial tract (ITT) were sequentially divided from the lateral border of the patella. Each was temporarily reattached to a cuff of soft tissue left on the patella using surgical clamps to determine its contribution to lateral restraint. The VLO was found to be the primary restraint in one-half of the knees. In one-third of the knees, all three of the structures contributed equally. In six knees, the primary restraint was the anterior fibers of the ITT, whereas the LR was the primary restraint in only two. The distal ends of these three structures were then resected to prevent rescarring and retethering. At a minimum follow-up period of two years, 87% had satisfactory relief of their patellar pain, had returned to normal activities, and had no or minimal physical findings of LFS. The procedure is recommended for patients who have failed other procedures and in those whose symptoms cannot be controlled by activity modification, exercises, bracing, or medication.

Adolescent↗
PubMedDate not supplied

[The patella and the femoro-patellar joint during rheumatoid polyarthritis].

The authors report 2 series of cases of rheumatoid arthritis, one prospective of 115 cases, the other retrospective of 72 cases, and note the frequency of clinical and radiological patellar and femoro-patellar involvement during this disease. Signs of active rheumatoid disease in the patella were present in 31 cases. The most common lesions of the femoro-patellar joint space are narrowing and lateral dislocation of the patella. The femoro-patellar lesions evolve in parallel to the femoro-tibial lesions, but dissociation is possible. The early detection of a femoro-patellar syndrome permits effective treatment by isometric rehabilitation of the quadriceps. On the most advanced lesions, and when pain is limited to the femur and patella, an operation of reaxation of the patella may provide remarkable functional improvement.

Adult↗
PubMed1979

Prosthetic resurfacing of the patella.

Accumulated data from many sources seem to indicate that prosthetic resurfacing of the patella may be an acceptable alternative to patellectomy in the treatment of chondromalacia patellae or patellofemoral arthrosis. A patellar prosthesis which is made of cobalt-chromium alloy is attached to a remnant of the original patella by means of the acrylic cement, polymethyl methacrylate. An analysis fo the results of the use of this prosthesis in 14 knees of 13 patients reveals excellent or good results in 13 cases and one poor result. The longest follow-up period was 2 years and 9 months and the shortest was 6 weeks. Based on current experience and the experience of others, prosthetic resurfacing of the patella may give the patient some years of pain-free patellofemoral function. This is especially true in patients with poor quadriceps reserve in whom the lever-arm distance of the extensor torque should be maiwtained. Until the ideal resurfacing material is developed, the use of presently available patellar prostheses with or without femoral prosthetic components, is recommended for further investigation.

Adolescent↗
PubMed1982

[Patella infera. Apropos of 128 cases].

A low patella is frequently a complication of a lesion of the knee but it can also present secondary symptoms of its own. The authors describe an original method for assessment of the vertical level of the patella. They have tried to establish a relationship between the low situation of the patella and pain of a certain type associated with limited flexion of the knee. Physiopathological and biomechanical evidence is taken into account. In most instances, a low patella is secondary either to a mechanical cause, natural or iatrogenic, or to an inflammatory cause such as algodystrophia. 29 patients out of 128 observed cases have been operated on. 17 of these were due to excessive transplantation of the anterior tibial tubercle. In most of the cases the tibial tubercle was transplanted upwards in association with a joint release. In only 3 cases a patellectomy was done. The results were excellent or good in half of the cases and unsatisfactory in the other half.

Adult↗
PubMed1981

[The Wiberg Forms of Patellae--are they disposing to early arthrosis? (author's transl)].

Autopsy examinations of patellae revealed that there is no statistical relationship between osteoarthritis and the different Wiberg and Baumgartl types of patella. Wiberg's and Baumgartl's types of patellae appear to be physiological form variants and without importance in the development of femoropatellar osteoarthritis. However, other morphological findings in the femoropatellar compartment, such as a ridge on the medial femoral condyle or a cartilagineous ridge on the medial part of the joint surface of the patellae may represent a prearthrotic factor.

Adult↗
PubMed1995

Post-traumatic differential osteoporosis of the patella.

The differential density developing after patella fractures between the proximal and distal poles has been attributed to avascular necrosis of the proximal fragment. Six cases are presented here where differential densities between the proximal and distal poles developed after trauma to the patella or knee. Based on the natural history of the condition, the rapidity of onset of the differential densities, osteoporosis of the whole patella later and complete resolution of the changes finally, we postulate that this phenomenon is due to a differential rate of osteoporosis of the proximal and distal parts of the patella because of the differences in their blood supply and not because of avascular necrosis of the proximal pole.

Adult↗
PubMedDate not supplied

Double patella syndrome with a form of multiple epiphyseal dysplasia.

OBJECTIVE: To present an interesting and unusual case of double patella syndrome in a patient with multiple epiphyseal dysplasia. The pertinent clinical and radiographic findings and a brief review of the literature are discussed. CLINICAL FEATURES: An 11-yr-old male patient suffered from occasional right hip pain and limited range of motion, as well as a nontender soft tissue mass in the right knee. Radiographic examination of the hips and knees demonstrated double-layered patellae and bilateral coxa magna deformity. INTERVENTION AND OUTCOME: Although surgery was initially recommended, conservative chiropractic management was employed and resulted in complete resolution of the patient's presenting hip symptoms. CONCLUSION: This case is the first reported of double patella seen on MRI and demonstrates the value of this technology in the noninvasive preoperative assessment of double patella syndrome. The patient's clinical and radiographic features led to the correct diagnosis.

Child↗
PubMed1995

Indirect forces and patella fracture after anterior cruciate ligament reconstruction with the patellar ligament. Case report.

Patella fracture is either an infrequent or underreported complication after anterior cruciate ligament (ACL) reconstruction using a portion of the patellar ligament. Patella fracture pattern has been related to the mechanism of injury. Direct fractures resulting from impaction forces delivered to the patella are typically stellate or comminuted. Indirect fractures resulting from tensile stresses applied across the extensor mechanism typically are displaced transverse disruptions. After ACL reconstruction using a portion of the patellar ligament, Y-shaped stellate fractures can occur. Fracture pattern seems related to the time elapsed since the harvest; stellate fractures occur following stumbles or slips without direct injury early in the postoperative period while transverse fractures occur late. This article describes two cases of patella stellate fractures that occurred in patients who underwent ACL reconstruction using patellar graft.

Adult↗