Mid-term outcomes after distally locked-to-standard primary stem exchange in 29 hip-prosthesis patients

AbstractBackgroundCementless locked femoral stems are used for revision surgery in patients with bone loss to induce spontaneous bone reconstruction, allowing subsequent replacement by a standard primary stem. The small number of patients and short follow-ups available to date preclude a valid assessment of this strategy.HypothesisAfter distally locked stem revision, replacement by a standard primary stem does not induce complications, and the quality of the bone reconstruction allows strong fixation of a regular primary stem.Materials and methodsWe retrospectively evaluated 29 patients in whom a distally locked femoral stem was replaced by a standard primary stem between 1998 and 2010 (cemented in 27, cementless in 2 cases). The reason for the procedure was stem breakage, stem migration, or thigh pain. Mean patient age was 63years (range, 39–78years). Outcomes were evaluated based on the Postel-Merle d’Aubigné [PMA] score and Harris Hip Score [HHS]. In addition, radiographs were obtained to assess prosthesis fixation and the Hofmann cortical index measured the bone reconstruction.ResultsThe distally locked stem was removed via a postero-lateral approach without femoral osteotomy in all the 29 cases. In one patient, an intra-operative fracture occurred during femoral preparation. Mean follow-up after the exchange procedure was 75months (range, 3–188months). Postoperative ccomplications occurred in 9 (32%) patients and consisted of chronic infection in 2 patients (after 3 and 76months), post-traumatic peri-prosthetic fractures treated with internal fixation in 3 patients (after 100, 138, and 182months), aseptic loosening in 3 patients (after 13, 39, and 122months), and recurrent instability in one patient (after 63months). All cause revision stem survival after 75months was 72% (95% confidence interval, 47%–87%). In the 19 patients who still had their revision stem at last follow-up, the mean PMA score was 16.7 (range, 13–18) and the mean HHS was 88.2 (range, 59–99). The Hofmann index remained unchanged [36.5% (range, 28%–58%) before the exchange and 32.9% (range, 20%–57%) after the exchange; P=0.129].DiscussionThis study confirms the feasibility of substituting a distally locked stem with a standard primary stem. No specific complications occurred and no technical difficulties arose when extracting the long stems. However, the 32% complication rate and, more specifically, the occurrence of loosening in 10% (3/29) of patients mandates caution in the use of this technique, which should not be proposed routinely, and suggests a need for considering cementless fixation of the standard primary stem.Level of evidenceLevel IV, retrospective study

Genome-wide association study of primary tooth eruption identifies pleiotropic loci associated with height and craniofacial distances

Twin and family studies indicate that the timing of primary tooth eruption is highly heritable, with estimates typically exceeding 80%. To identify variants involved in primary tooth eruption we performed a population based genome-wide association study of ‘age at first tooth’ and ‘number of teeth’ using 5998 and 6609 individuals respectively from the Avon Longitudinal Study of Parents and Children (ALSPAC) and 5403 individuals from the 1966 Northern Finland Birth Cohort (NFBC1966). We tested 2,446,724 SNPs imputed in both studies. Analyses were controlled for the effect of gestational age, sex and age of measurement. Results from the two studies were combined using fixed effects inverse variance meta-analysis. We identified a total of fifteen independent loci, with ten loci reaching genome-wide significance (p<5x10−8) for ‘age at first tooth’ and eleven loci for ‘number of teeth’. Together these associations explain 6.06% of the variation in ‘age of first tooth’ and 4.76% of the variation in ‘number of teeth’. The identified loci included eight previously unidentified loci, some containing genes known to play a role in tooth and other developmental pathways, including a SNP in the protein-coding region of BMP4 (rs17563, P= 9.080x10−17). Three of these loci, containing the genes HMGA2, AJUBA and ADK, also showed evidence of association with craniofacial distances, particularly those indexing facial width. Our results suggest that the genome-wide association approach is a powerful strategy for detecting variants involved in tooth eruption, and potentially craniofacial growth and more generally organ development

Refinement of 1p36 Alterations Not Involving PRDM16 in Myeloid and Lymphoid Malignancies

Fluorescence in situ hybridization was performed to characterize 81 cases of myeloid and lymphoid malignancies with cytogenetic 1p36 alterations not affecting the PRDM16 locus. In total, three subgroups were identified: balanced translocations (N = 27) and telomeric rearrangements (N = 15), both mainly observed in myeloid disorders; and unbalanced non-telomeric rearrangements (N = 39), mainly observed in lymphoid proliferations and frequently associated with a highly complex karyotype. The 1p36 rearrangement was isolated in 12 cases, mainly myeloid disorders. The breakpoints on 1p36 were more widely distributed than previously reported, but with identifiable rare breakpoint cluster regions, such as the TP73 locus. We also found novel partner loci on 1p36 for the known multi-partner genes HMGA2 and RUNX1. We precised the common terminal 1p36 deletion, which has been suggested to have an adverse prognosis, in B-cell lymphomas [follicular lymphomas and diffuse large B-cell lymphomas with t(14;18)(q32;q21) as well as follicular lymphomas without t(14;18)]. Intrachromosomal telomeric repetitive sequences were detected in at least half the cases of telomeric rearrangements. It is unclear how the latter rearrangements occurred and whether they represent oncogenic events or result from chromosomal instability during oncogenesis

Etude prospective de 25 reprises de prothèse totale de genou par un modèle d'implant à quilles centromedullaires press-fit, stabilisé par plot-came central et avec insert tibial rotatoire (résultats à 5 ans)

Introduction : Les principaux objectifs des reprises de prothèses totales de genoux sont d obtenir un bon résultat clinique et radiologique tout en limitant le plus possible le nombre de complications. Cette étude prospective de cas de reprise de prothèse totale de genou avait pour but d évaluer les résultats d une prothèse à quilles centro médullaires, contrainte par plot came central et avec insert tibial rotatoire. Matériel et méthode : L étude était mono centrique, prospective et reposait sur les 25 premières prothèses totales de genou de révision PFC Sigma TC3. L évaluation clinique était basée sur les scores clinique et fonction de la Knee Society (IKS). Les pertes de substances osseuses ont été définies en per-opératoire et classées selon la classification AORI. L analyse radiographique a été effectuée sur les radiographies numérisées grâce au logiciel IMAGIKA®. Résultats : Vingt quatre patients (25 prothèses) ont été inclus entre 2004 et 2007. L âge moyen des patients était de 65,1 ans. Il s agissait de 16 femmes et 8 hommes. L indication de la première arthroplastie était dans la majorité des cas une gonarthrose primitive (88%). L étiologie principale de la reprise était un descellement aseptique des implants (56%). Le taux d événements indésirables était de 36% en incluant les décès et les perdus de vue. Six patients ont nécessité une révision itérative de leur implant, 4 fois pour infection et 2 fois pour instabilité résiduelle. Aucun descellement aseptique n est à déplorer. Les scores IKS clinique et fonction étaient respectivement de 35,9 et 34,2, en préopératoire et respectivement de 86,2 et 81,3 au recul de 5 ans. Des lignes de condensation ont été retrouvées autour des quilles dans 69 % des cas. Des liserés radio clairs péri prothétiques ont été retrouvés dans 37 %, sans qu il ne soit retrouvé d incidence clinique. Conclusion : L utilisation de la prothèse PFC Sigma TC3 à plateau mobile permet de bon résultats cliniques avec une fixation stable des implants. Cependant ses indications doivent être rigoureusement sélectionnées. En cas de perte de substance sévères stade 2b ou 3 ou en cas d instabilité ligamentaire majeure, l indication est au prothèse plus contraintes par un plateau fixe ou de type charnière rotatoire.Introduction: The major goals of revision total knee arthroplasty include good clinical and radiographic results with a low complication rate. This prospective study of a case series of revision total knee arthroplasties with a constrained condylar prosthesis was performed in order to ascertain the role of this prosthesis and to determine whether it provided satisfactory results. Methods: The study was mono centric, prospective, based on the first 25 total knee revision PFC Sigma TC3. Clinical evaluation was based on clinical and function scores of the Knee Society (IKS). The bone defects in the femoral and tibial side were classified according to the Ander- son Orthopaedic Research Institute (AORI) bone defect classification guidelines. The radiographic analysis was performed on digitized radiographs using the software Imagika ®. Results: Twenty four patients (25 prostheses) were enrolled between 2004 and 2007. The average patient age was 65.1 years. There were 16 women and 8 men. The primary diagnosis was predominantly osteoarthritis (88%). The most common reason for revision was aseptic loosening of a component (56%). The complication rate was 36% including deaths and patients lost fo follow-up. Six patients required an iterative revision of their implant, for infection in 4 cases and for residual instability in 2 cases. No aseptic loosening is reported. Knee Society knee and functional scores were 35,9 and 34,2 points, respectively, before the operation and 86,2 and 81,3 points, respectively, at five years of follow-up. radiopaque lines were found around the stems in 69% of cases. radiolucent lines were found in 37%, Both of these were nonprogressive and without clinical impact. Conclusion: Revision total knee arthroplasty with use of the PFC Sigma TC3 Mobile weight-bearing allows good clinical results with a stable fixation of the implants. However, its indications must be carefully selected. In case of severe bone loss stage 2b or 3 or in major ligamentous instability, more constrained prosthesis whith fixed weight-bearing or rotating hinge must be available.AMIENS-BU Santé (800212102) / SudocSudocFranceF

Expression and Human Chromosomal Localization to 17q25 of the Growth-Regulated Gene Encoding the Mitochondrial Ribosomal Protein MRPL12

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Localization of Staf50, a Member of the Ring Finger Family, to 11p15 by Fluorescencein SituHybridization

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Localization of ARHG, a Member of the RAS Homolog Gene Family, to 11p15.5-11p15.4 by Fluorescence in Situ Hybridization

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One-year prospective comparative study of three large-diameter metal-on-metal total hip prostheses: Serum metal ion levels and clinical outcomes

SummaryIntroductionThe good clinical outcomes and low wear obtained with 28-mm metal-on-metal implants for total hip replacement prompted the development of large-diameter heads that more closely replicated the normal hip anatomy, with the goal of improving prosthesis stability. However, the blood release of metal ions due to wear at the bearing surfaces and the high rate of groin pain seen with large-diameter implants are causing concern. To determine whether these events are related to the geometry and metal composition of the prosthesis components, we conducted a prospective study of clinical outcomes and serum chromium and cobalt levels 1 year after implantation of three different acetabular cups.HypothesisSerum levels of metal ions are comparable with different types of large-diameter metal-on-metal total hip prostheses.Patients and methodsWe compared 24 Durom™ cups (D), 23 M2a Magnum™ cups (M2a), and 20 Conserve Total™ (C) cups regarding serum chromium and cobalt levels, Postel-Merle d’Aubigné (PMA) scores and Oxford Hip Scores (OHS), as well as radiographic cup orientation and position at 1-year follow-up. Mean age was 66 years (45–85 years), mean body mass index was 28 Kg/m2 (18–45), patients were almost equally divided between males and females, and the reason for hip replacement was primary hip osteoarthritis in 65 patients and avascular necrosis in two. Metal ions were assayed in serum from blood drawn through non-metallic catheters, using mass spectrometry.ResultsDislocation occurred in two patients (one D and one M2a) and revision to change the bearing couple was required in two patients in the D group. Serum cobalt levels in the C group were significantly higher (P=0. 0003) than in the two other groups (7.5μg/L versus 2. 7μg/L with D and 2. 2μg/L with M2a). Clinical outcomes were better in the M2a group (PMA, 17.7 [16–18]; and OHS, 15.2 [12–30]; P<0.05). The PMA score and OHS were 17.5 (16–18) and 18.2 (12–42), respectively, with D; and 16.75 (10–18) and 22. 2 (12–42), respectively, with C cups. When all three cup models were pooled, serum ion levels were higher in patients with pain than without pain (chromium, 7.1μg/L versus 2.1μg/L [P=0.002], and cobalt, 8μg/L versus 2.6μg/L [P=0.0004]).DiscussionSerum chrome and cobalt levels increased after metal-on-metal total hip replacement, and the increase was greater with large-diameter implants than previously reported with 28-mm implants. Persistent pain was significantly associated with higher metal ion levels, with a probable cobalt cut-off of about 8μg/L. Differences in modular head-neck concepts may explain the observed variations.Level of evidenceIII, prospective comparative study

Localization of the Ribonuclease L Inhibitor Gene (RNS4I), a New Member of the Interferon-Regulated 2–5A Pathway, to 4q31 by Fluorescencein SituHybridization

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