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Comparison of patella lead with blood lead and tibia lead and their associations with neurobehavioral test scores.

OBJECTIVE: Lead exposure in adults is associated with worse cognitive function in cross-sectional and longitudinal studies. Previous studies have mainly examined relations with blood lead or cortical bone lead; few have examined trabecular bone lead. METHODS: We performed a cross-sectional analysis of the relations of patella lead and other lead biomarkers with measures of neurobehavioral and peripheral nervous system function in 652 lead workers. RESULTS: Patella lead was found to be associated with worse performance on seven of 19 tests of manual dexterity, sensory vibration threshold, and depressive symptoms. The associations of patella lead with cognitive function were essentially similar to those with blood lead or tibia lead but of somewhat lower magnitude. CONCLUSIONS: In this study, measurement of patella lead did not aid causal inference regarding cognitive effects when compared with blood lead and tibia lead.

Adult↗

The unstable patella in children.

The authors reviewed 102 unstable patellas which had been observed and treated from 1964 to 1990. They were divided according to whether they suffered from traumatic dislocations, recurrent dislocations or malformative instability. The clinical findings were the major stage of the check up. In the field of imaging, standard X-rays had to be performed in all cases. MRI was of interest in the congenital dislocations, in order to thoroughly investigate the soft tissue anomalies. Two types were described: Type 1 was observed in children with joint laxity, but without major X-ray anomalies; Type 2, a major femoropatellar dysplasia could be formed with some bone deformity. The latter was observed in the malformative instability. Four different surgical procedures have been used, from the release of the retinacula of patella to the medial displacement of the patellar tendon or the tibial tuberosity. This study emphasises the concept of a true development dysplasia of patella (DDP) which can gather the different varieties of the instability of patella.

Adolescent↗

Tripartite patella: late appearance of a third ossification center in childhood.

Bilateral radiographic progression of the supero-lateral fragment of a bipartite- into a tripartite patella with unilateral symptoms. An 8 year old girl presented a bilateral bipartite patella Stage III as an incidental finding after fall on the flexed right knee. Serial radiographs two years later revealed a bilateral progression of the bipartite- into a tripartite patella with complaints only on the post-traumatic right side. Observation was opted as therapy. There was no correlation of symptoms and radiological findings of the fragmentation of the bipartite- into a tripartite patella. Therefore we conclude the etiology of a bilateral late appearance of a third ossification center.

Child↗

The painful bipartite patella.

Two skeletally immature patients with bipartite patella, a lesion normally classified as a developmental variation, proved to have a symptomatic lesion with a traumatic etiology. In both patients, appropriate treatment resulted in complete subsidence of symptoms; one patient was treated with cast immobilization, while the other eventually required surgical resection. In addition, normal and bipartite patellar specimens from skeletally immature cadavers were histologically and morphologically assessed. These clinical and anatomic studies suggest that in some cases a bipartite patella may be a traumatically induced, chondroosseous disruption of the superolateral pole of the incompletely ossified patella, analogous to Sinding-Larsen-Johansson disease at the inferior patellar pole or Osgood-Schlatter disease in the tibial tuberosity. The possibility of bipartite patella being such a chronic stress fracture in a symptomatic patient should be considered in order to render appropriate treatment.

Adolescent↗

Cartilage of the patella. Topographical variation of glycosaminoglycan content in normal and fibrillated tissue.

The variation in the glycosaminoglycan content was studied at different sites of the patella, both where the cartilage was intact and where it showed varying degrees of fibrillation. It was found that when the cartilage surface was intact the glycosaminoglycan content was the same at the different sites of the patella. Local fibrillation always gave rise to a local lowering of fixed charge density, the magnitude of the latter correlating well with the visual assessment of the severity of the lesion. Even in the presence of severe lesions, if there was a site left on the patella where the cartilage was visually normal, its fixed charge density was also at a normal level. Thus, the depletion of glycosaminoglycans is a local phenomenon, limited to the area of fibrillation. The glycosaminoglycan content of normal cartilage is lower in the knee joint than in the hip. This fact, together with the existence of high pressure during load bearing, may be responsible for the greater frequency of destructive lesions affecting the cartilage of the patella compared with that of the hip.

Adolescent↗

Thermography in the detection and follow up of chondromalacia patellae.

Although diagnostic criteria for chondromalacia patellae exist, the disease is often accompanied by physical signs which are limited or non-diagnostic. Thermographic examination was performed in 157 patients with clinical diagnosis of chondromalacia patellae in 86 patients after surgical treatment for chondromalacia, and in 308 controls. Thermography can help the clinicians in establishing the diagnosis of chondromalacia patellae, but by itself is not sufficiently specific. The specificity of thermography was dependent on age, ranging from 90% for the 15-24 year age group to 65% for the 45-54 year age group. Sensitivity of the method was 68%. Thermography can disclose other knee disorders which imitate chondromalacia patellae.

Adolescent↗

Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella.

PURPOSE: To assess magnetic resonance (MR) imaging findings after acute lateral patellar dislocation (LPD) with emphasis on the medial patella restraints and to describe a medial patellar impaction deformity. MATERIALS AND METHODS: Knee MR images obtained within 8 weeks after LPD were evaluated for medial retinacular and medial patellofemoral ligament (MPFL) disruption, vastus medialis obliquus (VMO) edema and/or elevation, and other derangements. One hundred patients with no evidence of prior LPD were evaluated as controls. The Student t test was used for statistical comparisons. RESULTS: Eighty-two examinations were performed in 81 patients with LPD (mean age, 20 years; age range, 9-57 years). Seventy-six percent (62 of 82 examinations) showed medial retinacular disruption at its patellar insertion; 30% (25 of 82), at its midsubstance. The MPFL femoral origin was identified in 87% (71 of 82); of these, 49% (35 of 71) showed injury. Forty-eight percent (39 of 82) showed more than one site of injury to the medial stabilizers; 45% (37 of 82) showed edema or hemorrhage at the inferior VMO. Mean VMO elevation in the coronal plane of the adductor tendon was 2.2 cm, with a range of 0.6-4.5 cm (in control subjects, 0.9 cm; range, 0.1-2.5 cm; P <.001). At the inferomedial patella, 70% (57 of 82) of LPD examinations showed osteochondral injury and 44% (36 of 82) showed concave impaction deformity (0 of 100 control subjects). Other examination findings in LPDs included contusions of the lateral femoral condyle (66 [80%] of 82 examinations) or medial patella (50 [61%] of 82), intraarticular bodies (12 [15%] of 82), effusion (45 [55%] of 82), medial collateral injury (nine [11%] of 82), and meniscal tear (nine [11%] of 82). CONCLUSION: Injury to the medial retinaculum, MPFL, and VMO may be identified at MR imaging after acute LPD. Concave impaction deformity of the inferomedial patella is a specific sign of prior LPD.

Adult↗

Cartilage lesions of the patella in recurrent patellar dislocation.

BACKGROUND: The etiology of patellar cartilage lesions in recurrent patellar dislocation has been poorly understood. HYPOTHESIS: The pathology of cartilage lesions of the patella accompanied by recurrent patellar dislocation can be analyzed. STUDY DESIGN: Series of case reports. METHODS: In 70 knees from 57 patients with recurrent patellar dislocation, the cartilage lesions of the patella were examined using arthroscopy and/or macroscopic observation. The average age of the patients was 22 years (range, 13 to 40 years). Lesions that involved only softening were not included. RESULTS: Sixty-seven knees (96%) had articular cartilage lesions of the patella, and only 3 knees had no change. Fissuring was observed in 53 knees (76%). The most common site of fissuring was on the central dome. There were basically two types of fissuring: multiple longitudinal fissuring and marginal/radial fissuring. Fibrillation and/or erosion were observed in 54 knees (77%). Of these, 40 knees had fissuring and 14 did not have fissuring. The main site of fibrillation and/or erosion was the medial facet. CONCLUSIONS: Cartilage lesions of the patella in recurrent patellar dislocation cases were very common. Fissuring was observed mainly on the central dome, and fibrillation and/or erosion were observed mainly on the medial facet.

Adolescent↗

Efficacy of lateral retinacular release for painful bipartite patella.

We treated painful bipartite patella with a modified lateral retinacular release technique in 15 patients (16 knees). Bony union of the separated fragment and the patella was obtained in 15 of 16 knees within 8 months of surgery. Sustained traction acting on the patella laterally and proximally is presumed to cause the pain. The surgical technique to reduce this force proved effective not only in relieving the pain but also in achieving bony union. Painful bipartite patella can lead to excessive lateral pressure syndrome or patellar compression syndrome, these complications can be effectively treated by this surgical technique. In contrast to conventional treatments, such as excision of smaller fragments or osteosynthesis to achieve bony union, the modified lateral retinacular release technique is easy to perform and provides an effective means for relieving patellofemoral pain and achieving bony union.

Adolescent↗

Comparing 2-year outcomes of anterior cruciate ligament reconstruction using either patella-tendon or semitendinosus-tendon autografts: a non-randomised prospective study.

PURPOSE: To compare the results of anterior cruciate ligament (ACL) reconstructions using either a patella-tendon autograft or a semitendinosus-tendon autograft. METHODS: Based on surgeon experience and preference, 68 patients underwent ACL reconstruction using either a quadruple-strand semitendinosus autograft (n = 34) or a central one-third bone-patella tendon-bone autograft (n = 34). Each patient was assessed preoperatively and postoperatively at 3, 6, and 24 months using the International Knee Documentation Committee (IKDC) knee score, Biodex muscle strength and endurance testing, and the KT1000 instrumented arthrometer test of knee laxity to anterior translation. All assessments at the 2-year follow-up were performed by the same physician and physiotherapist. RESULTS: While ACL reconstruction improved knee stability and IKDC knee scores significantly, there was no statistically significant difference between semitendinosus- and patella-tendon autograft reconstructions in terms of long-term knee score or laxity to anterior translation. Semitendinosus graft reconstruction was associated with less donor-site morbidity and hamstring weakness. Meniscectomy was associated with poorer long-term knee scores. CONCLUSION: ACL reconstruction is associated with a significantly better IKDC knee score and laxity measurement at 2-year follow-up. However, we were unable to demonstrate a significantly better long-term outcome in knee score or laxity to anterior translation with either a patella-tendon autograft or a semitendinosus-tendon autograft.

Adolescent↗

The arthroscopic treatment of chondromalacia patellae.

Three hundred and nineteen patients who had chondromalacia patellae and persistent patellofemoral pain after six months of conservative management underwent arthroscopy and arthroscopic surgery. The results in four aetiological groups were reviewed at one year and five years after operation. Morbidity was minimal. Lavage produced early remission in all groups. Shaving offered a particular advantage in the post-traumatic group. Lateral release plus shaving and lavage was beneficial in the group with maltracking patellae and in half of the idiopathic group. In the group with unstable patellae, lateral release produced good results in only one in four patients. In conclusion, we consider that arthroscopic surgery has a useful role to play in the management of chondromalacia patellae.

Arthroscopy↗

The biomechamcal and surgical solutions for patella implant in total knee arthroplasty.

A basic fault in designs of patella implants that calls for a prompt remedy is the inadequate polyethylene thickness in contact areas. The requirement for thickness of patella implants should be similar to the requirement set up by the FDA in 1993 regarding the tibial implants, that is, a minimal thickness of 8 mm. A solution is presented for the optimal design of the patella implant and for the appropriate surgical technique. The implant's undersurface that fixes to bone is concave and has a 1-cm wide but 5 to 6 mm short central peg that does not risk the integrity of the bone. Fixation of the concave aspect to the convex aspect of the bony patella strongly enhances resistance to medio-lateral and supero-inferior shear forces. The circumferential facet of the implant 8 mm thick assures uniform thickness of the entire implant and assures optimal mechanical properties of the polyethylene. The articulating surface is tailored to conform to the corresponding femoral trochlear groove and condyles. It can be made to fit any femoral component of any knee implant.

Arthroplasty, Replacement, Knee↗

Long-term complications after total knee arthroplasty with or without resurfacing of the patella.

The long-term complications related to the patella were retrospectively evaluated for 891 knees (684 patients) that had had a total arthroplasty, with or without resurfacing of the patella, with use of an unconstrained, condylar, posterior-cruciate-preserving prosthesis. The study population comprised two groups of patients who were similar in size, age, sex distribution, and diagnosis. One group (396 knees [303 patients]) had had a total knee arthroplasty with patellar resurfacing and the other group (495 knees [381 patients]) had had the same procedure without resurfacing. The average duration of follow-up was six and one-half years (range, two to fifteen years). The decision to resurface the patella was based on subjective inspection of the articular surface and on assessment of patellar tracking at the time of the operation. Resurfacing was performed if there was loss of cartilage, exposed bone, gross surface irregularities, or tracking abnormalities. Complications occurred an average of three years (range, immediately postoperatively to nine years) after the operation in the group that had had resurfacing and an average of four years (range, immediately post-operatively to ten years) postoperatively in the group that had not had resurfacing. In the group that had had resurfacing, there was loosening of the patellar component in five knees, patellar subluxation in four knees, fracture of the patella in three knees, rupture of the patellar tendon in three knees, and chronic peripatellar pain in one knee. In the group that had not had resurfacing, the complications included patellar subluxation in five knees, rupture of the patellar tendon in two knees, and chronic peripatellar pain in fifty-one knees.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Congenital dislocation of the patella.

OBJECTIVE: Our objective was to present the imaging findings for congenital dislocation of the patella, an uncommon condition with variable clinical manifestations in patients of different ages. CONCLUSION: Sonography can clearly illustrate the presence and location of the laterally displaced patella and the anatomy of adjacent joint structures. The high resolution for soft-tissue, cartilaginous, and bony structures of the immature skeleton makes sonography a valuable tool in the management of congenital dislocation of the patella. Conventional radiography is a simple method for diagnosis once ossification of the patella has commenced and for postoperative follow-up. MRI allows visualization of fine anatomic details and relationships between the involved structures of the extensor mechanism and is the technique of choice for preoperative planning.

Child, Preschool↗

Chondromalacia of the patella. Physical signs in relation to operative findings.

Cartilaginous changes on the patella are common and were demonstrated in 50 out of 100 patients who underwent operation for intraarticular disease of the knee joint. In order to clarify further the signs of this condition, the physical signs were related to the operative findings. Retropatellar crepitation was present in most cases, but cannot be called pathognomonic. Pain on grating and tenderness on palpation of the patella in fact occurred together only in cases with cartilaginous changes on the patella. On the other hand, cartilaginous changes were found in several cases without such signs, a condition which perhaps should be interpreted as cartilaginous changes only, not as the symptom complex chondromalacia of the patella in which there ought to be a history of symptoms.

Adolescent↗

Chondromalacia of the patella. Incidence, macroscopical and radiographical findings at autopsy.

In a post-mortem series of 59 persons aged 10-50 years, 91 of the 118 patellae exhibited cartilaginous changes. These changes were most common in the older age groups and usually affected the medial articular facet where they were also most extensive and most profound. Clinical and radiological assessment showed this facet to be less suited to articulation with the femur because of its convex joint surface, central ridges, and prominences. Radiography using tangential views of the entire patella and of 2 mm thick slices of the patella showed in cases with macroscopically normal cartilage a less dense bony structure medially and a denser structure laterally. Even in the presence of distinct cartilaginous changes this difference in bone density did not alter essentially. In particular, there was no definite sclerosing medially, where the changes in the cartilage were most marked. Osteophyte formation was sparse, but most common in the older age groups, and laterally. Osteophytes were seen only on patellae with cartilaginous changes.

Adolescent↗

Complications of the PCA anatomic patella.

A retrospective review of the total knee arthroplasties performed using the PCA anatomic patella (Howmedica, Rutherford, NJ) was undertaken after a high rate of complications was noted. Eighty-seven knees in 75 patients were evaluated with an average follow up of 16 months. Eighteen complications of the patella in 14 knees were found (16%); these included lateral subluxation (10 knees), fracture of the patella (5 knees), patellar tendon rupture (2 knees) and prosthetic loosening (1 knee). Seven patients required secondary procedures with the ultimate result greatly compromised in four patients. It is proposed that if the component is not precisely aligned, the eccentric shape and central ridge increases the forces acting at the patella and leads to an increased risk for complications, making the component less forgiving than the more standard dome-shaped patellar component.

Aged↗

Contact stresses with an unresurfaced patella in total knee arthroplasty: the effect of femoral component design.

Compressive contact stresses between the patella and the anterior femur were measured with a digital electronic sensor before and after total knee arthroplasty (TKA) in 10 cadaver knee specimens. Contact stresses were measured first in normal knees, then after TKA with the Insall-Burstein Total Condylar, Miller Galante II, Ortholoc II, Porous Coated Anatomic, and Profix knee prostheses implanted without resurfacing the patella. The Insall-Burstein, Miller-Galante II, and Ortholoc II prostheses had significantly higher contact stresses than the normal knee throughout the flexion arc. The Porous Coated Anatomic, which has a smooth patellar groove, maintained contact area as in the normal knee and did not have significantly higher contact stresses at flexion angles <90 degrees. At flexion angles > or =105 degrees, patellofemoral contact occurred in two small areas as the patella encountered the intercondylar notch in all components except the Profix. The Profix maintained full contact and low compressive stresses throughout the full flexion arc because of its posteriorly extended patellar groove. Design features of the patellofemoral portion of TKA components are important factors that affect contact stresses in the patellofemoral joint. These features likely will affect the clinical results of TKA with an unresurfaced patella.

Arthroplasty, Replacement, Knee↗