C. Mazel

Rôle de la courbure rachidienne sagittale dans la survenue des luxations précoces après reprise de prothèse totale de hanche: À propos d’une analyse prospective de 49 reprises de prothèse totale

Resume La statique pelvienne et lombaire de 49 patients operes pour changement de prothese totale de hanche entre septembre 2000 et mars 2002 a fait l’objet d’une etude prospective. Cinq patients ont presente une luxation postoperatoire, malgre l’absence apparente de defaut de positionnement des implants. La valeur moyenne de la pente sacree etait significativement differente (p = 0,006) chez les patients s’etant luxes en comparaison avec ceux indemnes de luxation. Cette difference restait significative (p = 0,017) si on limitait l’etude aux 33 patients ne presentant aucun facteur de risque associe de luxation postoperatoire (antecedents de luxation recidivante, ou d’interventions multiples, ou infectieux, pseudarthrose du grand trochanter). Notre etude evoque le role de la statique pelvienne et lombaire dans la survenue de luxations postoperatoires apres reprise de prothese totale de hanche qui doit etre analysee une fois les causes classiques eliminees. Elle permet enfin, d’isoler des sujets a risque, chez qui des artifices techniques anti-luxation peuvent etre discutes.PURPOSE OF THE STUDY Hip dislocation after revision total hip arthroplasty (RTHA) is a frequent post-operative complication. Certain risk factors are well identified (nonunion of the greater trochanter, history of recurrent dislocation or infection, multiple procedures), the role of spine morphological remains to be fully examined. The purpose of this prospective analysis was to assess the role of spine morphology in post-operative dislocations. MATERIAL AND METHODS Forty-nine patients who underwent RTHA between September 2002 and March 2002 were evaluated prospectively. A complete pre- and postoperative spinal work-up was available for all patients to evaluate the lumbopelvic static using the Legaye and Duval Beaupère morphology criteria and the pelvic-femoral angle to assess hip joint extension. Pre-, per- and post-operative data including the usual risk factors for dislocation related to the clinical situation and the technique used were recorded on a digital datasheet. Five patients developed postoperative dislocation despite the absence of defective implant position. There was no relation with access (p=0.832) or pelvic-femoral angle (p=0.515). RESULTS The mean value of the sacral slope was significantly different (p=0.006) in patients who developed dislocation in comparison with the other patients. This difference remained significant (p=0.017) for the cohort of 33 patients who had no associated risk factor for postoperative dislocation (history of recurrent dislocation or infection, multiple procedures, tight nonunion of the greater trochanter). DISCUSSION Our results suggest that the morphology of the lumbar spine can be involved in the risk of postoperative dislocation. The morphology of the lumbar spine affects the pelvic static and thus the landmarks usually used for implantation, but it can also limit the amplitude of pelvic movement when changing from the sitting to the standing position, which would be compensated for by greater hip movement, particularly extension. The method we used did not fully take into account the consequences of changes in spinal balance due to thoracic deformations nor to analgesic (or not) hip flexion and subsequent deformation of the lumbar spine.

Comparison between two different concepts of lumbar posterior osteosynthesis implants A finite-element analysis

SummaryThe present study is a numerical comparison using finite-element analysis (FEA) of two different concepts of spinal fixation devices when implanted. These implants are 1) the Easy®, “rigid” Screw/Rod (ø 6mm) system; 2) the Twinflex®, “dynamic” system (ø 2 X 2.5 mm ELF). A parameterised 3D FEA model of an L3-sacrum segment, developed by Lavaste, Skalli & Robin, was used. Geometric and mechanical models of each implant were then constructed, before being inserted in the spinal segment model. Then, for model validation, these two L3-S2 instrumented segmental models were submitted to similar boundary conditions as used in a previous in vitro comparison of the same implants. Flexion loaddisplacement curves were then controlled using experimental results. Loads acting on screws and longitudinal elements were calculated and analysed for a better understanding of the intrinsic differences between both constructs. Load-displacement responses of both constructs were quite similar (L3 sagittal rotation at 10 N.m = ~1.5°), while loads in the implant were not. For example, the axial push-in forces at the S1 screws were equal to 30 N for the Twinflex®, and 150 N for the Easy® Screw/Rod system. The pull-out forces at the S2 screws were respectively 100N and 200 N for the Twinflex and Screw/Rod Concept. At other levels, axial forces were all lower than 60 N, the Twinflex®, values being higher than the Easy® ones. Bending moments along screws were respectively 0.7 N.m and 1.4 N.m at the L3 level for the Twinflex® and the Easy® systems. At lower levels, values were all below 0.6 N.m, again with a reversed proportion. Bending moments calculated along longitudinal elements were always lower than 0.3 Nm for the Twinflex®, and up to 2 N.m for the Easy® system. Axial forces in the Twinflex® longitudinal elements were about 160 N, and about 100 N in the Easy® rods. Although the numerical approach mainly provides tendencies, it clearly seems that reducing flexural stiffness of lumbar fixation induces more homogeneous load transmission along the construct, and greatly reduces axial push-in/pull-out forces at the S1/S2 levels, and all this without reducing the rigidity of the whole construct. Conversely, it has been shown that “rigid” longitudinal elements may concentrate stresses at the construct extremities, relieving loads at intermediate levels at the same time, which may be the sign of a stress-shielding-like phenomenon. These differences arise from a fundamental difference between both kinds of longitudinal elements in the way they transmit loads. The ø 6 mm rods mainly oppose a bending reaction torque to the applied flexion moment, whereas the Twinflex® construct mainly balances the applied flexion torque by an anterior compression of the anterior column, combined with posterior traction on its longitudinal elements (ELF).

Influence de l’indice de masse corporelle sur la réalisation d’une prothèse totale de hanche par voie d’abord antérieure réduite

Resume L’objectif de cette etude prospective etait de determiner l’influence de l’indice de masse corporelle (IMC) dans la faisabilite d’une arthroplastie totale de hanche par voie d’abord mini-invasive. Quatre-vingt-six patients (88 hanches) ont ete operes consecutivement selon cette technique, par voie d’abord anterieure sur table orthopedique, avec une incision cutanee de 7 cm, dont la longueur a toujours ete mesuree en postoperatoire. Les donnees peri-operatoires (douleur, saignement, duree d’intervention) ont ete correlees avec l’IMC. A trois mois, tous les patients ont ete revus et les complications mecaniques ou infectieuses ont ete relevees. L’analyse du positionnement et du scellement de la piece acetabulaire, ainsi que celle du retablissement de la longueur des membres inferieurs a ete systematiquement realisee sur les radiographies de controle. Si l’IMC n’a pas represente une contre-indication formelle a la realisation de ces interventions, l’evaluation des resultats a montre un allongement de la duree de l’intervention et une augmentation du saignement, statistiquement significatifs, chez les patients ayant un IMC > 25 (ɛ = 4,28 et ɛ = 2,66). De meme, l’allongement plus important de la cicatrice en postoperatoire chez les patients a IMC > 25 (t = 5,01), temoigne des contraintes a exercer sur la peau pour realiser ces interventions et peut donc exposer a des risques de necrose ou d’infection plus importants. En revanche, le positionnement de l’implant acetabulaire (ɛ = 0,245), son scellement (p > 0,5) et le retablissement de l’equilibre des membres inferieurs (ɛ = 1,14) n’ont pas ete influences par l’IMC.

Ostéotomie de fermeture postérieure par impaction intracorporéale pour dos plat postopératoire: À propos d’une série de 22 cas

PURPOSE OF THE STUDY There is increasing interest in sagittal balance as an important element when planning treatment of spinal deformations. Posture disorders, particularly flatback, can be observed after surgical treatment of scoliosis. The frequency of flat back syndrome has increased with the development of spinal surgery. MATERIAL AND METHODS Posterior osteotomy is designed to resolve these problems. Two techniques are used: the Smith-Petersen procedure and transpedicular subtraction osteotomy. We adopted the second procedure, adding two technical modifications: installation on an orthopaedic table and intracorporeal cancellous impaction. We performed closed posterior osteotomy by intracorporeal impaction and report here our results in a series of 22 patients with postoperative flat back treated between July 1999 and June 2002. Mean age at surgery was 52 years. There were sixteen women and six men. All patients had a history of spinal surgery with fusion. They had had 2.1 spinal operations on average with a maximum of seven. All patients complained of severe postural pain. They had difficulty bending forward and standing back up. Radiographically, we noted altered spinal and pelvic angles and an abnormal plumb line from C7 to the promontory. RESULTS We analyzed outcome at 21 months on average. Preoperatively five patients had 12 levels of non-union. Osteotomy was performed at L4 in nineteen patients and L3 in three. A rigid instrumentation was used in all cases. Osteosynthesis material was implanted after correction of the deformation with no particular problem for spinal stability or reduction. Mean operative time was 180 minutes and mean blood loss was 1680 ml. A complementary anterior approach was required in one patient. Intraoperative complications were dominated by dural breaches in five patients, high paraplegia not directly related to the osteotomy in one patient, regressive S1 paresia occurred in one patient and transient cruralgia which regressed in 4 to 6 months in four patients. We also observed functional intestinal obstruction in one patient and severe depression in another. There were no infections or deaths. We also observed two cases of predominant correction at the discal level and not the vertebral level. All operated patients felt their posture was improved and were able to maintain the upright position for prolonged periods. Flexion of the lower limbs was improved. Mean correction of lumbar lordosis was 25.1 degrees (range 12-39). Mean sacral slope was 33 degrees . Mean correction of the position of C7 on the promontory plumb line was 72 mm. This variable was highly altered preoperatively (95.6 mm) and was improved after osteotomy in all patients. At last follow-up, there was one case of nonunion which had been successfully revised. DISCUSSION The literature on osteotomy for the treatment of flat back is sparse. Our series of subtraction osteotomy is the largest reported to date. Preoperative and intraoperative planning remain a topic of debate and require further study.Resume Les auteurs presentent une serie de 22 cas de dos plat post-chirurgical traites par osteotomie trans-pediculaire de fermeture posterieure sur une periode de 3 ans (juillet 1999-juin 2002). Ils ont modifie la technique princeps en proposant l’impaction intracorporeale du spongieux ce qui permet une simplification du geste operatoire et une moindre morbidite. L’âge moyen au moment de l’intervention etait de 52 ans. Tous les malades presentaient des antecedents de chirurgie rachidienne avec arthrodese. La position penchee en avant avec difficulte a se redresser etait une plainte constante. Sur le plan radiologique, il existait des anomalies des parametres rachidiens et pelviens. En peroperatoire, nous avons confirme ou retrouve une pseudarthrose chez 5 patients. L’osteotomie a ete realisee au niveau de L4 dans 19 cas et au niveau de L3 dans 3 cas. L’osteosynthese a ete assuree avec une instrumentation rigide dans tous les cas. L’instrumentation a ete toujours implantee apres correction de la deformation sans prejudice particulier tant pour la stabilite du rachis que pour la reduction. La duree moyenne de l’intervention a ete de 180 minutes. La moyenne des pertes sanguines a ete de 1 680 ml. La voie anterieure a ete jugee necessaire dans un seul cas. Les complications peroperatoires ont ete rares. Il n’y a eu aucun deces. Le recul moyen est de 25 mois. Tous les operes de la serie ont ete ameliores en position debout et parvenaient a rester debout de facon prolongee sans difficulte, notamment sans flechir les genoux. La correction moyenne de la lordose lombaire a ete de 25,1° avec des extremes de 12 et 39°. La moyenne de la pente sacree postoperatoire etait de 33°. La correction moyenne de la position de C7 par rapport au promontoire ( plumb line ) a ete de 72 mm. Ce critere etait toujours perturbe en preoperatoire (95,6 mm), il a ete constamment ameliore de facon importante apres l’osteotomie. Au dernier recul, il n’y a eu qu’un seul cas de pseudarthrose, repris avec succes. La litterature est pauvre en ce qui concerne la realisation des osteotomies dans le traitement du dos plat postoperatoire. La planification pre et peroperatoire reste malgre tout un point imprecis.

Painful patellofemoral instability secondary to peroperative patellar fracture during bone-patellar tendon-bone autograft harvesting for anterior cruciate ligament reconstruction.

Reconstructive surgery of the anterior cruciate ligament (ACL) of the knee in young active patients is a routine procedure, but with certain risks that need to be taken into account. Peroperative patellar fracture after bone-patellar tendon-bone autograft harvesting is a rare complication, which can significantly impair the functional outcome of ACL single-bundle reconstruction. We report the case of a patient presenting with disabling patellofemoral syndrome 3 years after arthroscopic ACL reconstruction by bone-tendon-bone autograft, revealing unnoticed mal-union of a iatrogenic sagittal patellar fracture. Patellar osteotomy corrected this painful iatrogenic patellar instability.

Modified exeter technique for the reconstruction of femoral bone loss in revision total hip arthroplasty. Does prosthesis stability affect remodeling of the graft

SummaryExeter technique is accompanied by significant prosthesis subsidence, in about 20% to 38% of cases leading to 6 to 11% of early re-revision. This migration may break up the cement and thus yield to particle generation which may induce osteolysis. The goal of the modified technique is to obtain stem stability by limiting reconstruction to it proximal 4/5th, and cementing distal fifth directly to the host bone. Twenty one hips (20 patients) were reviewed. (Average follow-up: 18 months, range: 6–29 months). Radiographic assessment revealed stem stability in 18 cases. Allograft remodeling or cortical reconstitution occurred in 17 cases. Thus loading of the graft consecutive to stem migration is not the sole factor accounting for both allograft remodeling and host bone corticalization. Inversely, this stability protects the cement from possible fractures and their consequences.RésuméLa reconstruction des pertes de substance osseuse fémorales lors de la chirurgie de reprise de prothèses totales de hanche, constitue un problème difficile. La technique d’Exeter, qui utilise des greffons spongieux morcelés et impactés dans la cavité fémorale, décrite par Simon et Gie apparaît très séduisante. Mais la migration précoce de la pièce fémorale constatée par les promoteurs de la technique et par d’autres reste préoccupante.Gie et Simon considèrent cette migration comme sans risque, puisque la prothèse se stabilise secondairement. Nous restons toutefois soucieux des conséquences de cette migration sur un manteau de ciment fin et irrégulier qui peut se fragmenter. Nous avons donc modifié la technique originale dans le but de donner à la prothèse une stabilité primaire satisfaisante.TechniqueUne fois la prothèse descellée enlevée, le fémur est alésé pour permettre l’insertion aisée du canon d’un «pistolet à greffon». Celui-ci permet de descendre dans le fémur préalablement obstrué, un cylindre creux de greffons spongieux. Le canon est recouvert d’un treillis de mersylène qui permet de stabiliser le cylindre de greffe en regard du défect à reconstruire mais aussi d’éviter la dispersion de l’os spongieux lors du passage des impacteurs en particulier au travers de pertes de substance segmentaires quand elles existent. Le façonnage et la compaction de la greffe sont obtenus par le passage d’impacteurs de tailles progressivement croissantes, jusqu’à ce qu’ils tiennent fermement dans la greffe. La tige est ensuite scellée de manière rétrograde, directement au contact de l’os du patient pour le cinquième distal et dans la greffe pour les 4/5e proximaux.Résultats21 hanches chez 20 patients ont été opérées selon cette technique entre octobre 1996 et février 1998. Le recul moyen et la médiane de suivie sont de 18 mois (Minimum 6 et maximum 29).La perte de substance osseuse fémorale était souvent sévère, (Cinq type 3A et 5 type 3B selon la classification de Paproski) mais limitée en hauteur. (Pas de type 4 selon la classification de l’Endo Klinik).ComplicationsElles sont au nombre de 8 et intéressent 7 patients.Deux sont majeures. Une patiente a présenté, à la suite d’une chute, une fracture du fémur sous la queue de la prothèse, 6 mois après l’intervention, reprise par prothèse longue queue pontant la zone de fracture. Un autre patient a présenté une récidive infectieuse qui a conduit à l’ablation de la prothèse et la mise en résection tête col.Aucun patient n’a actuellement été repris pour un descellement aseptique.Résultats cliniquesLe score moyen post opératoire selon les critères de Harris est de 86.7 (Minimum 12 maximum 100). Quatorze patients (66%) sont indolores, 5 (24%) ont une douleur à la fatigue. 2 patients sont douloureux (10%)Par ailleurs, 13 patients (62%) marchent sans canne, 5 (24 %) utilisent une canne pour les marches prolongées, 2 (10%) ont besoin d’une canne en permanence et un (4%) ne peut se déplacer.Résultats radiologiquesTrois migrations se sont produites dans le manteau de ciment, mais elles sont toujours restées inférieures ou égales à 3 mm. Dans ces trois cas, le scellement distal était insuffisant.L’analyse de l’évolution de la greffe a montré, dans 9 cas une réparation de la corticale du patient, associée dans 5 cas à l’apparition dans la greffe des trabéculations. Dans 2 cas sont apparues des trabéculations dans l’allogreffe de manière isolée et enfin dans 6 cas l’allogreffe s’est corticalisée.Cas cliniqueLors de la reprise d’un de nos patient du fait d’une récidive septique, il a été possible de prélever un volumineux fragment comprenant de l’os du patient, de la greffe, du ciment et du voile de mersyléne. L’examen histologique montre que les greffons osseux sont entièrement réhabités avec des ostéocytes bien visibles dans les logettes ostéocytaires avec un liseré ostéoblastique bordant les travées, témoignant d’une réhabitation de l’allogreffe.ConclusionCette modification de la technique d’Exeter apparaît reproductible, puisque nous avons obtenu le résultat souhaité dans environ 85% des cas. L’usage du voile de mersylène permet de reconstruire des défects segmentaires par voie, endomédullaire protégeant ainsi la vascularisation périostée. Les modifications de l’aspect de l’allogreffe, constatées dans la grande majorité des cas de notre série, ne différent pas de celles observées avec la technique originale. Ceci nous incline à penser qu’il existe d’autres phénomènes que la mise en compression de la greffe, par la migration de la prothèse, pour sa transformation en os vivant. En revanche, cette stabilité primaire protège un scellement qui n’est pas toujours homogène et qui peut être à l’origine d’une possible fragilisation.

Synthesis of the 18th ArgoSpine Symposium

Abstract The subject of this 18th Symposium of ArgoSpine Association was the space of the intervertebral discs. Space of the intervertebral discs must be initially defined anatomically and histologically. A geometrical rebuilding in 3D is possible and must allow a modeling of the intervertebral discs. The physiology of the disc, its nutrition, must be known, in particular that of the center of the disc. The disc constitutes the base of the balance of the rachis, balances which can be only dynamic. The degenerative cascade by the loss of the proteoglycans involves the loss of the biomechanical properties of the disc. The consequences of this degenerative cascade are the base of all the vertebral pathology of origin of the intervertebral discs and even of the posterior articular facets. The origin of the pains and the diagnosis, especially at the lumbar level, are studied by the speakers. Traumatology of the intervertebral discs is the object of a particular chapter. Finally, the average therapeutic ones, that is, decompression of the intervertebral discs, fusion of the intervertebral discs, the recovery of mobility of the intervertebral discs, and the capacity of restoration of space of the intervertebral discs, are studied in detail. The infection of the disc is studied in detail.

Synthesis of the 19th ArgoSpine Symposium.

Abstract After a short introduction of the meeting by the President 2015, Wilco Peul, the opening lecture was delivered by Bart Koes, who dealt with Health Technology Assessment and Guidelines. Then, it was the turn of Carmen Vleggert to show whether there was any Evidence for the Use of Implants in Spinal Stenosis. The final presentation of this session was delivered by Björn Strömqvist who dealt with Surgery for Lumbar Disc Herniation, patients’ selection and outcomes. Developing the subject of “Do Not’s”, Jeremy Fairbank described the UK experience for Low Back Pain. Yves Coppens then took over and further elaborated on “Lucy’s legacy”. Prof. Coppens recalled that Lucy is a partial skeleton of a pre-human found in Ethiopia among other remains. Prof. Alan Crockard offered what he called “a whimsical view” of his practice of Craniocervical Surgery. Wafa Skalli was asked to speak about Finite Element Analysis of the Spine and Arts et Métiers Paris Tech where there is a long tradition of close collaboration between engineers and clinicians. Rune Hedlund, who will serve as 2016 Symposium President, further elaborated on Scoliosis with a focus on Unsolved Issues in Adolescent Idiopathic Scoliosis Treatment.

Detection of Asymptomatic Venous Thrombosis following Hip Replacement Surgery: Retrospective evaluation of routine screening by duplex ultrasonography based on 286 cases

This study evaluates a pragmatic approach using duplex ultrasonography (US) for detecting venous thromhosis (VT) after total hip arthroplasty (THA). Venous B-mode and colour duplex US examination of both legs including a systematic evaluation of calf veins was performed twice during hospitalisation in 286 consecutive patients. VT was diagnosed in 31 patients (12%). Thrombosis was asymptomatic in 28 patients (90%), and was bilateral or concerned the non-operated leg in 6 patients (19,4%). No clinical pulmonary embolism occurred during hospitalisation. Prior phlebitis and age over 70 were identified as statistically significant risk-factors (p<0,02 and p<0.04 respectively). All patients were seen at three months. Four patients (1.6%) developed VT between hospital discharge and the 3-month follow-up visit. Venous US performed twice after THA detected VT in 31 patients, 90% of these were asymptomatic. This approach might explain the absence of pulmonary embolism (PE) in our series, and support a systematic evaluation of the vein of the lower limb with ultrasonography after THA.

The place of arthrography for component loosening and hip aspiration for diagnosis of infection

SummaryThe aim of that study was to evaluate the place of arthrography for component loosening and of hip aspiration for diagnosing infection. 52 arthrograms were done under local anesthesia in radiology suites under fluoroscopic guidance. If no fluid was aspirated a non bacteriostatic saline solution was injected and reaspirated. Liquid was then analized. Component loosening was evaluated by plain films and by arthrography and compared to the surgical findings in all cases. The sensitivity of arthrography (94.5%) was better than that of plain films (83%) for evaluating socket loosening, but was worse (77%vs 92%) for femoral component evaluation. They were no false positive evaluations in socket loosening, but false negatives occurred in 2 cases with supporting material such as screws and plates. Results for femoral loosening are more difficult to analyse. The sensitivity (77%) and the specificity (81%) of arthrography are lower than plain films (92% and 88%). Most authors consider that the femoral component is loose when more than one third of the stem has a lucent line. 4 patients had such findings and were operated on. In each case the stem was found to be stable at operation. We removed the stem in two cases and left it in place in two old patients. We simply cleaned the granuloma from the proximal part of the femur. It means that arthrography did not really fail to make the diagnosis. But surgical procedures in case of incomplete radiolucent lines are not mandatory and depend on the individual surgeons philosophy. Sensitivity of hip aspiration to identify periprosthetic germ was 66% and a specificity was 100%. No false positives were found. Only one patient over 41 without any sign of active infection had a positive hip aspiration. This test is not sensitive enough to be a prerequiste test before total hip revision but has to be done in cases of clinical or suspected sepsis.