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At least 883 records · Page 49Linked to original sources

Autograft bone-patella tendon-bone plug comminution with loss of ligament fixation and stability.

Two cases are described in which bone plug comminution caused a loss of femoral fixation after endoscopic bone-patellar tendon-bone, anterior cruciate ligament autograft reconstruction. Clinically there was loss of knee joint stability, and radiographically the bone graft had dislodged. One case was salvaged by graft inversion, with femoral interference screw and tibial traction suture fixation. The second case required graft replacement with a patella bone-quadriceps tendon autograft.

Adolescent↗

Anatomic rotational relationships of the proximal tibia, distal femur, and patella: implications for rotational alignment in total knee arthroplasty.

The orientation of the femur, tibia, and patella are important considerations in total knee arthroplasty. Our goal was to describe the relationships between the femoral epicondylar (FE) axis, posterior femoral (PF) axis, posterior tibial (PT) axis, patellar (PAT) axis, and patellar ligament (PL). A secondary goal was to determine where the short axis of the tibial tray intersects the patellar ligament as a function of tibial component rotation. Thirty normal magnetic resonance imaging (MRI) scans were analyzed. Strong relationships were found between the FE and PAT axes (2 degrees +/- 3 degrees, r(2) = 0.73), and between the FE and PF axes (6 degrees +/- 2 degrees, r(2) = 0.77). When the tibial baseplate was aligned along the PT axis, 30% of the cases were in an ideal position. When the FE axis was used, 73% were ideal.

Adult↗

Gradual low riding of the patella during postoperative course after total knee arthroplasty in osteoarthritis and rheumatoid arthritis.

Patellar height in the lateral view of radiograms was measured on 94 knees of 61 women before and after total knee arthroplasty in order to study postoperative changes of position. The mean age of patients at surgery was 58.4 years (range, 30-77 years). Eighty-one knees were rheumatoid and 13 osteoarthritic. Inserted prostheses were Kinematic anteriorly joined type in 49 knees, Kinematic posterior cruciate retention type in 19, and UCI type in 26. The observation period ranged from 6 months to 9 years, with an average of 2.6 years after surgery. The ratio of length of the patellar ligament to that of the patella (Insall-Salvati's ratio) decreased by more than 10% of preoperative value in 61 knees, remained unchanged in 31, and increased in only 2. The average ratio was 0.93 +/- 0.16 before surgery and 0.75 +/- 0.20 at the final follow-up examination (P less than .01).

Adult↗

Freehand resection of the patella in total knee arthroplasty referencing the attachments of the quadriceps tendon and patellar tendon.

A freehand technique of patellar resurfacing using anatomic references was prospectively evaluated. This technique utilizes an osteotomy beginning at the inferior pole of the patella just posterior to the insertion of the patellar tendon and is carried proximally posterior to the insertion of the quadriceps tendon. Evaluation of 55 total knee arthroplasties in 41 patients showed an average restored patellar thickness within 0.1 mm. The overall patellar thickness was restored to within 1 mm of its preoperative thickness in 50 (91%) of 55 knees. Patellar tilt was equal to or less than 4 degrees in 42 (89%) of 47 arthroplasties evaluated radiographically. The patellar thickness averaged 17.9 mm, well above the critical value of 15 mm reported in the literature.

Adult↗

MR arthrography in chondromalacia patellae diagnosis on a low-field open magnet system.

OBJECTIVE: The purpose of this study was to compare the diagnostic efficacy conventional MRI and MR arthrography (MRA) in the diagnosis of chondromalacia patella (CP) on a low-field open magnet system (LFOMS), correlated with arthroscopy. SUBJECTS AND METHODS: Forty-two patients (50 knees) with pain in the anterior part of the knee were prospectively examined with LFOMS, including T1-weighted, proton density-weighted and T2-weighted sequences. All were also examined T1-weighted MRI after intraarticular injection of dilue gadopentetate dimeglumine. Two observers, who reached a consensus interpretation, evaluated each imaging technique independently. Thirty-six of the 50 facets examined had chondromalacia shown by arthroscopy, which was used as the standard of reference. The sensitivity, specificity and accuracy of each imaging technique in the diagnosis of each stage of CP were determined and compared by using the McNemar two-tailed analysis. RESULTS: Arthroscopy showed that 16 facets were normal. Four (30%) of 13 grade 1 lesions were detected with T1. Four lesions (30%) with T2 and three lesions (23%) with proton-weighted images were detected. Seven (53%) of 13 grade 1 lesions were detected with MRA. Grade 2 abnormalities were diagnosed in two (33%) of six facets with proton density-weighted pulse sequences, two (33%) of six facets with T1-weighted pulse sequences, in three (50%) of six facets with T2-weighted pulse sequences, in five (83%) of six facets with MRA sequences. Grade 3 abnormalities were diagnosed in three (71%) of seven facets with proton density- and T1-weighted images, five (71%) of seven facets with T2-weighted pulse sequences, six (85%) of seven facets with MRA sequences. Grade 4 CP was detected with equal sensitivity with T1-, proton density- and T2-weighted pulse sequences, all showing seven (87%) of the eight lesions. MRA again showed these findings in all eight patients. All imaging techniques were insensitive to grade 1 lesions and highly sensitive to grade 4 lesion, so that no significant difference among the techniques could be shown. CONCLUSION: All imaging technique studied had high specificity and accuracy in the detection and grading of CP; however, MRA was more sensitive than T1-weighted and proton density-weighted MR imaging on a LFOMS. Although the arthrographic techniques were not significantly better than T2-weighted imaging, the number of false-positive diagnosis was greatest with T2-weighted MRI.

Adult↗

Hamstrings vs. patella tendon for anterior cruciate ligament reconstruction: a randomised controlled trial.

A randomised controlled trial was performed to evaluate early outcome for two types of anterior cruciate ligament reconstruction. Sixty patients undergoing cruciate reconstruction were randomized into two groups. Group PT underwent reconstruction using a patella tendon autograft, whereas Group (SG) had a semitendinosus/gracilis autograft (SG). IKDC, Lysholm, and Tegner scores, KT1000 values and muscle strength were recorded pre-operatively, at 6 months and 1 year follow up. The functional scores, activity level, muscle strength and anterior tibial translation improved in both groups. No significant difference between groups was found for any measurement at 6 months and 1 year despite adequate study power. The study indicates that the 1 year results for either technique are equally favourable.

Analysis of Variance↗

Patella baja following chronic quadriceps tendon rupture.

Patella baja is a complication of chronic quadriceps tendon rupture. In this case we present the treatment of this problem by the proximal transfer of the tibial tubercle allowing an environment in which the quadriceps tendon can heal.

Aged↗

Regulation of glomerular basement membrane collagen expression by LMX1B contributes to renal disease in nail patella syndrome.

Basement membrane (BM) morphogenesis is critical for normal kidney function. Heterotrimeric type IV collagen, composed of different combinations of six alpha-chains (1-6), is a major matrix component of all BMs (ref. 2). Unlike in other BMs, glomerular BM (GBM) contains primarily the alpha 3(IV) and alpha 4(IV) chains, together with the alpha 5(IV) chain. A poorly understood, coordinated temporal and spatial switch in gene expression from ubiquitously expressed alpha 1(IV) and alpha 2(IV) collagen to the alpha 3(IV), alpha 4(IV) and alpha 5(IV) chains occurs during normal embryogenesis of GBM (ref. 4). Structural abnormalities of type IV collagen have been associated with diverse biological processes including defects in molecular filtration in Alport syndrome, cell differentiation in hereditary leiomyomatosis, and autoimmunity in Goodpasture syndrome; however, the transcriptional and developmental regulation of type IV collagen expression is unknown. Nail patella syndrome (NPS) is caused by mutations in LMX1B, encoding a LIM homeodomain transcription factor. Some patients have nephrosis-associated renal disease characterized by typical ultrastructural abnormalities of GBM (refs. 8,9). In Lmx1b(-/-) mice, expression of both alpha(3)IV and alpha(4)IV collagen is strongly diminished in GBM, whereas that of alpha1, alpha2 and alpha5(IV) collagen is unchanged. Moreover, LMX1B binds specifically to a putative enhancer sequence in intron 1 of both mouse and human COL4A4 and upregulates reporter constructs containing this enhancer-like sequence. These data indicate that LMX1B directly regulates the coordinated expression of alpha 3(IV) and alpha 4(IV) collagen required for normal GBM morphogenesis and that its dysregulation in GBM contributes to the renal pathology and nephrosis in NPS.

Animals↗

Molecular cytogenetic detection of 9q34 breakpoints associated with nail patella syndrome.

The nail patella syndrome (NPS1) is an autosomal dominant disorder characterised by dysplasia of the finger nails and skeletal abnormalities. NPS1 has been mapped to 9q34, to a 1 cM interval between D9S315 and the adenylate kinase gene (AK1). We have mapped the breakpoints within the candidate NPS1 region in two unrelated patients with balanced translocations. One patient [46,XY,t(1;9)(q32.1;q34)] was detected during a systematic survey of old cytogenetic files in Denmark and southern Sweden. The other patient [46,XY,t(9;17)(q34.1;q25)] was reported previously. D9S315 and AK1 were used to isolate YACs, from which endclones were used to isolate PACs. Two overlapping PAC clones span the 9q34 breakpoints in both patients, suggesting that NPS1 is caused by haploinsufficiency due to truncation or otherwise inactivation of a gene at or in the vicinity of the breakpoints.

Chromosome Fragility↗

Deletion of a branch-point consensus sequence in the LMX1B gene causes exon skipping in a family with nail patella syndrome.

Nail patella syndrome (NPS) has been shown to result from loss of function mutations within the transcription factor LMX1B. In a large NPS family a 17 bp intronic deletion encompassing a consensus branchpoint sequence was observed to segregate with the NPS phenotype. RNA analysis demonstrated that deletion of the branchpoint sequence resulted in skipping of the downstream exon. A mechanism to explain this phenomenon is presented.

Alternative Splicing↗

A neurological phenotype in nail patella syndrome (NPS) patients illuminated by studies of murine Lmx1b expression.

Nail patella syndrome (NPS) is an autosomal dominant disorder affecting development of the limb, kidney and eye. NPS is the result of heterozygous loss-of-function mutations in the LIM-homeodomain transcription factor, LMX1B. Recent studies suggest that the NPS phenotype may be more extensive than recognized previously including neurologic and neurobehavioral aspects. To determine whether these findings correlated with the expression of Lmx1b during development, an internal ribosomal entry site-LacZ reporter was inserted into the 3'UTR of the endogenous murine gene. The pattern of Lmx1b expression during the development of the limb, eye and kidney correlates with the NPS phenotype. Additional sites of expression were observed in the central nervous system (CNS). The effects of the absence of Lmx1b in the CNS were determined in lmx1b-/- mice by histology and immunocytochemistry. Lmx1b is required for the differentiation and migration of neurons within the dorsal spinal cord. The inability of afferent sensory neurons to migrate into the dorsal horn is entirely consistent with diminished pain responses in NPS patients.

Animals↗

Interaction of the LMX1B and PAX2 gene products suggests possible molecular basis of differential phenotypes in Nail-Patella syndrome.

The LMX1B gene, encoding a protein involved in limb, kidney and eye development, is mutated in patients affected by Nail-Patella syndrome. Inter- and intrafamilial variability is common in this disorder for skeletal abnormalities, presence and severity of nephropathy and ocular anomalies. Phenotypic variability might depend on interactions of the LMX1B causative gene with other genes during development of both kidney and eye, which might act as modifier genes. Results are presented on the interaction between LMX1B and PAX2 proteins, obtained by both direct yeast two-hybrid assay and coimmunoprecipitation. Such interaction provides support to further studies on pathways underlying important developmental processes.

Animals↗

Genotype-phenotype studies in nail-patella syndrome show that LMX1B mutation location is involved in the risk of developing nephropathy.

Nail-patella syndrome (NPS) is characterized by developmental defects of dorsal limb structures, nephropathy, and glaucoma and is caused by heterozygous mutations in the LIM homeodomain transcription factor LMX1B. In order to identify possible genotype-phenotype correlations, we performed LMX1B mutation analysis and comprehensive investigations of limb, renal, ocular, and audiological characteristics in 106 subjects from 32 NPS families. Remarkable phenotypic variability at the individual, intrafamilial, and interfamilial level was observed for different NPS manifestations. Quantitative urinanalysis revealed proteinuria in 21.3% of individuals. Microalbuminuria was detected in 21.7% of subjects without overt proteinuria. Interestingly, nephropathy appeared significantly more frequent in females. A significant association was established between the presence of clinically relevant renal involvement in an NPS patient and a positive family history of nephropathy. We identified normal-tension glaucoma (NTG) and sensorineural hearing impairment as new symptoms associated with NPS. Sequencing of LMX1B revealed 18 different mutations, including six novel variants, in 28 families. Individuals with an LMX1B mutation located in the homeodomain showed significantly more frequent and higher values of proteinuria compared to subjects carrying mutations in the LIM domains. No clear genotype-phenotype association was apparent for extrarenal manifestations. This is the first study indicating that family history of nephropathy and mutation location might be important in precipitating individual risks for developing NPS renal disease. We suggest that the NPS phenotype is broader than previously described and that NTG and hearing impairment are part of NPS. Further studies on modifier factors are needed to understand the mechanisms underlying phenotypic heterogeneity.

Adolescent↗

Phenotype severity and genetic variation at the disease locus: an investigation of nail dysplasia in the nail patella syndrome.

The genetic bases underlying the range and severity of phenotypes in Mendelian disorders is poorly understood; however, improvements in this area have the potential to facilitate analysis of oligogenic disorders. The nail dysplasia observed in Nail Patella Syndrome (NPS) was selected as a quantifiable variable within a Mendelian disorder, for which data could be readily obtained, to allow investigation of the genetic basis of variation. Analysis of SNP haplotypes across the LMX1B gene demonstrated association between the haplotype of the mutant allele and the variability in the nail score (p = 0.024). These results are in contrast to those obtained previously, which supported a modifying role for the wild-type allele. Since there is no evidence that particular mutations, or classes of mutation, are associated with the variation (p > 0.5), further work is required to identify the elements associated with the LMX1B gene that mediate phenotypic severity.

DNA Mutational Analysis↗

Three cases of patella fracture in 1,320 anterior cruciate ligament reconstructions with bone-patellar tendon-bone autograft.

Between September 1992 and December 1996 we reviewed three transverse displaced fractures of the patella occuring in 1,320 ACL reconstructions using bone-patellar tendon-bone autograft. All the patients suffered local injury to the donor knee between 8 and 12 weeks postoperatively. Immediate rigid fixation using single or double anterior tension band allowed early mobilization and full weight bearing. Between 6 and 9 months after fracture, the screws and the wire were removed and the grafts tested. Results of the pivot shift and Lachman test under anesthesia were negative and arthroscopic visualisation showed the graft to be intact. Postoperative assessment included the Lysholm and Tegner scales, the International Knee Documentation Committee Evaluation form (IKDC), KT-1000 arthrometer, and isokinetic dynamometer strength testing. No significant differences in the final outcome were noted between reconstructions complicated by patellar fracture and normal ACL reconstructions.

Adult↗

Bipartite patella fracture.

Bipartite patella fracture is an uncommon injury that has rarely been described in the literature. It can be quite debilitating in the competitive athlete and is often overlooked by the treating physician. A bone scan can be helpful in confirming the diagnosis, and appropriate treatment often results in a successful outcome.

Adult↗

Medial patellar ligament splitting for the treatment of upward fixation of the patella in 7 equids.

OBJECTIVE: To describe a surgical technique for splitting the proximal third of the medial patellar ligament (MPL) in horses and ponies with upward fixation of the patella (UFP), and to report outcome. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Four horses and 3 Shetland ponies. METHODS: With ultrasound guidance, the proximal third of the MPL was split by percutaneous use of a no. 15 scalpel blade. The rationale for this surgical procedure was to induce a localized desmitis with subsequent ligament thickening. No anti-inflammatory drugs were administered, and horses and ponies were exercised the day after surgery. Clinical, radiographic and ultrasonographic follow-up evaluation was obtained. RESULTS: No short-term or long-term complications were observed, and no patients had clinical signs of UFP after surgery. This clinical effect was attributed to a 2- to 3-fold increase in size of the proximal part the MPL from an induced localized desmitis. CONCLUSIONS-Percutaneous splitting of the proximal third of the MPL resolved UFP in equids. CLINICAL RELEVANCE: Splitting of the proximal third of the MPL is effective for treatment of UFP and allows rapid return to normal activity.

Animals↗