Dominique Chauveaux

Mechanical properties of cellulose in orthopaedic devices and related environments

The authors have undertaken a series of mechanical tests in order to assess the performance of regenerated cellulose under either static or dynamic conditions, and to evaluate its long-term behaviour under mechanical stress. In this respect, bending stiffness, resistance to compression, creep under compressive stress, in vitro and in vivo ageing and fatigue resistance were studied. It appears that this material demonstrates mechanical properties which depend upon its density, which is itself related to its water content. Moreover, this material is very stable under dynamic stress. This could be an interesting property for use in orthopaedic devices.

Viscosupplementation of the ankle: A prospective study with an average follow-up of 45.5 months

INTRODUCTION Providing pain relief for ankle osteoarthritis and delaying the need for a radical surgery procedure is difficult to achieve with analgesics that have limited efficacy or are not devoid of substantial side effects. HYPOTHESIS The goals of this study were to evaluate the efficacy of viscosupplementation, explore which factors better predict Patients response and propose an injection protocol. MATERIALS AND METHODS Eighteen patients (26 ankles) with ankle osteoarthritis were included, with seven of them having received multiple series of injections. The average age was 60 years. Series of three injections, performed in the operating room under fluoroscopy-guidance, were evaluated after 4 and 12 months and then annually with the AOFAS score; patient satisfaction was also assessed. RESULTS The average AOFAS score increased significantly from 61.8 ± 15 before the injections to 74.4 ± 14.5 and 73.7 ± 16.6 after 4 and 12 months, respectively. The average follow-up was 45.5 months and 73% of patients were satisfied or very satisfied. There were no adverse effects or intolerance. In patients receiving more than one series of injections, the average delay between series was 27.8 (range 15-43) months. Five patients had a radical surgery procedure after an average of 27 months of effective viscosupplementation. DISCUSSION This prospective study showed that viscosupplementation had a significant positive effect (P<0.05) in patients with ankle osteoarthritis when a three-injection protocol was used every two years on average. Neither etiology nor severity of the osteoarthritis was predictive of the response. In our opinion, fluoroscopy-guidance is essential for these injections. LEVEL OF EVIDENCE Level IV cohort study.

Treatment of moderate hallux valgus by percutaneous, extra-articular reverse-L Chevron (PERC) osteotomy

AIMS The aim of this study was to report a single surgeon series of consecutive patients with moderate hallux valgus managed with a percutaneous extra-articular reverse-L chevron (PERC) osteotomy. PATIENTS AND METHODS A total of 38 patients underwent 45 procedures. There were 35 women and three men. The mean age of the patients was 48 years (17 to 69). An additional percutaneous Akin osteotomy was performed in 37 feet and percutaneous lateral capsular release was performed in 22 feet. Clinical and radiological assessments included the type of forefoot, range of movement, the American Orthopedic Foot and Ankle (AOFAS) score, a subjective rating and radiological parameters. The mean follow-up was 59.1 months (45.9 to 75.2). No patients were lost to follow-up. RESULTS The mean AOFAS score increased from 62.5 (30 to 80) pre-operatively to 97.1 (75 to 100) post-operatively. A total of 37 patients (97%) were satisfied. At the last follow up there was a statistically significant decrease in the hallux valgus angle, the intermetatarsal angle and the proximal articular set angle. The range of movement of the first metatarsophalangeal joint improved significantly.. There was more improvement in the range of movement in patients who had fixation of the osteotomy of the proximal phalanx. CONCLUSION Preliminary results of this percutaneous approach are promising. This technique is reliable and reproducible. Its main asset is that it maintains an excellent range of movement. TAKE HOME MESSAGE The PERC osteotomy procedure is an effective approach for surgical management of moderate hallux valgus which combines the benefits of percutaneous surgery with the versatility of the chevron osteotomy whilst maintaining excellent first MTPJ range of motion.

Tibiotalocalcaneal Arthrodesis Using a Straight Intramedullary Nail

Background: Tibiotalocalcaneal (TTC) arthrodesis is a proven solution for severe hindfoot arthropathy that reestablishes stability for plantigrade gait and alleviates pain, while correcting deformity. Intramedullary nailing is an effective option for fixation. The aim of this study was to determine clinical outcome, analyze the fusion rate, and determine final hindfoot alignment in a consecutive series of patients using a single-design straight intramedullary nail. Methods: This study evaluated 63 patients treated between 2006 and 2010 with at least 36 months of follow-up. Ten patients were excluded because of study inclusion criteria, and 4 were lost to follow-up, leaving 49 patients available for review. The average follow-up was 70.7 ± 15.1 months. Results: The American Orthopaedic Foot and Ankle Society score improved from 29.7 ± 15.1 before arthrodesis to 65.8 ± 14.6 after (P < .001) with 83.7% (41/49) of patients stating they were satisfied or very satisfied with the outcome. The hindfoot angle improved from −3 ± 15 degrees (varus) before the arthrodesis to 3.5 ± 4 degrees (valgus) after; the tibiotalar angle averaged 103 ± 4.2 degrees after the arthrodesis. Fusion occurred in both joints in 86% (42/49) of patients and in 93% (91/98) of all joints. The average time to fusion was 4.5 ± 2 months. Current smokers had a significantly (P = .03) higher risk of complications. Use of an allograft, with or without bone morphogenetic protein 2, led to comparable results even in the presence of a large bone defect. Conclusion: These results are comparable to previously published studies using intramedullary nailing to achieve tibiotalocalcaneal arthrodesis. The complication concerns typically associated with straight nails were not found. We recommend using a retrograde intramedullary nail for the fixation of TTC arthrodesis and adding an allograft in cases of significant bone loss. Level of Evidence: Level IV, consecutive case series.

AKILE™ total ankle arthroplasty: Clinical and CT scan analysis of periprosthetic cysts

INTRODUCTION Despite good clinical results following total ankle replacement (TAR), the development of large periprosthetic cysts (>400 mm(2)) in the medium-term is a source of concern. OBJECTIVE The primary objective of this study was to detect any large periprosthetic cysts in a cohort of AKILE™ patients using radiographs and CT scans, and then to compare these findings to published ones. MATERIAL AND METHODS A total of 127 TAR procedures were performed between June 1995 and January 2012. We retrospectively reviewed 68 cases with the newest AKILE™ implant design that had a minimum follow-up of 36 months. The average follow-up was 81 ± 33 months; eight patients were lost to follow-up. The outcomes consisted of analyzing radiographs (A/P and lateral weight bearing views, Meary view and lateral views of flexion/extension) and helical CT scans, performing clinical evaluations (range of motion, AOFAS score, Foot Function Index, pain levels) and determining the survivorship of TAR implants. RESULTS TAR survival at 5 years was 79% for in situ implants and 62% for revision-free implants. The AOFAS score improved from 33.7 ± 14.7 to 77.1 ± 15.1 (out of 100) and the pain sub-score was 30.2 ± 9.7 (out of 40) at the last follow-up. The average ankle range of motion was 32.3° ± 12.7° on the radiographs. CT scan revealed Type A cysts (<200 mm(2)) under the talar implant in 52% of cases and in the tibia in 50% of cases; these cysts were smaller than 100 mm(2) in 80% of cases and had no effect on the implants. No periprosthetic cysts larger than 400 mm(2) in size were identified. DISCUSSION The medium-term functional results and survivorship are comparable to those reported for other TAR designs. The incidence of cysts was low overall and there were no large-diameter cysts, which should improve long-term survival. The implants design and materials likely played a role in preserving the periprosthetic bone stock. The AKILE™ TAR has distinctive features related to the low rate of large periprosthetic cysts in the medium-term. LEVEL OF EVIDENCE IV (retrospective case series).

TricOs TM and Fibrin Sealant Combined for Bone Defect Filling: From Pre-Clinical Tests to Prospective Clinical Study. Preliminary human data

The association of TricOsTM (Macroporous Biphasic Ceramic Phosphate MBCP granules) and the fibrin sealant FS VH S/D 4, has been developed to answer a challenging request of orthopaedic surgeons: a biocompatible, osteogenic, mouldable, and self-hardening bone substitute able to fill randomly shaped bone defects. The aims of this study was the evaluation of the performance and safety of the bioactive bone substitute TricOs™ associated with a fibrin sealant in regeneration of functional bone. The pre-clinical tests were conducted to optimize MBCP granules size and ratio MBCP–FS VH S/D 4 (sheep maxillary sinus grafting, femoral epiphysis defect in rabbits, long bone defects in sheep). A clinical study design was set up as an exploratory prospective French multicentric phase II study sponsored by INSERM (Institut National de la Santé et de la Recherche Médicale). The application was the TOV (Tibial Osteotomy of Valgisation) using osteosynthesis and bone substitute: TricOs™ mixed with the fibrin sealant (FS VH S/D 4) for filling the space created. The follow up is 13 months with safety checks, clinical assessments, highsensitivity X-ray, and CT-scan imaging. A bone sample will be collected from the reconstructed area at 12 months, during the osteosynthesis material removal surgery. The principal criterion is CT-scan imaging performed 12 months after TOV surgery, before material removal, to assess qualitative and quantitative bone reconstruction. Animals’ studies demonstrate that the biomaterial is safe to use and shows osteoconductive properties, granules resorption and bone ingrowth at the expenses of the implants. As for clinical trial, 7 patients are today included in the study: This paper present the first results obtained from X-ray imaging during follow up.

133 Quel bilan iconographique pour une instabilité douloureuse de la cheville

Introduction Le but de ce travail est de definir le meilleur bilan d’examens complementaires devant une instabilite douloureuse talo-crurale, et une fois pour toutes, de preciser l’interet ou non des cliches dynamiques dans cette indication. Materiel et Methode Entre aout 1998 et avril 2002, 29 patients (16 hommes, 13 femmes, d’âge moyen 33 ans) consultant pour une instabilite douloureuse de la cheville ont beneficie de cliches dynamiques instrumentes (varus et tiroir anterieur), et d’un arthroscanner. Ils ont ete revus pour en analyser les resultats, par rapport au diagnostic retenu, mais egalement au traitement realise. L’instabilite etait dominante dans 68 % des cas, la douleur dans 32 %, mais les deux composantes toujours presentes. Quatre-vingt quatre pour cent des patients avaient une activite sportive reguliere perturbee par l’instabilite. Resultats Les cliches dynamiques n’ont mis en evidence un varus que chez 28 % des patients et un tiroir anterieur chez 21 %. L’arthroscanner a fait le diagnostic positif dans 93 % des cas : laxite chronique chez 62 % des patients, parfois associee a d’autres lesions (chondropathie talienne, conflit tissulaire ou osseux) ; conflit tissulaire isole (17,2 %) ou associe a une chondropathie (6,9 %), chondropathie isolee (6,9 %) associee a une laxite chronique (3,4 %), conflit osseux isole (3,4 %). Dans 7 %, il a ete interprete comme totalement normal. Au recul moyen de 51 mois, 66 % etaient tres satisfaits, 31 % satisfaits, 3 % decus et aucun patient mecontent de sa prise en charge. Discussion La litterature est assez riche en etudes montrant le peu de sensibilite des cliches dynamiques. Le diagnostic principal de laxite chronique a ete retenu chez 18 patients, dont seuls 53 % avaient une epreuve dynamique positive. Conformement a la litterature, la valeur predictive positive de l’examen reste tres moyenne, autour de 50 %. La sensibilite de l’arthroscanner en revanche est excellente (93 %) et il permet surtout 24 % de diagnostics associes, pouvant modifier l’indication therapeutique (32 % d’arthroscopie talo-crurale voire sous-talienne). Il reste encore aujourd’hui l’examen le plus performant pour analyser le cartilage et sa sensibilite reste excellente pour le diagnostic des interpositions tissulaires (20,7 % dans la serie). La grande satisfaction des patients montre la pertinence de ce raisonnement, qui loin de complexifier la demarche diagnostique, la rend a nos yeux extremement simple et payante. Conclusion L’arthroscanner, qui affirme le diagnostic dans 93 % des cas et retrouve 1/4 de lesions associees, s’impose donc devant une instabilite douloureuse de la cheville, pour affiner le diagnostic, et poser la meilleure indication chirurgicale. Les cliches dynamiques, tres specifiques, mais peu sensibles semblent inutiles.

284 Traitement de l’avant-pied rhumatoïde par arthrodèse du premier rayon et réalignement métatarsien avec mise en place de prothèses bouton : à propos de 69 pieds

Introduction Evaluation du traitement chirurgical de l’avant pied rhumatoide severe par arthrodese de l’articulation metatarso-phalangienne du premier rayon et realignement des metatarsiens lateraux avec interposition de protheses boutons avec un recul moyen de 8 ans. Materiel Il s’agit d’une etude retrospective portant sur 46 patients (69 pieds) atteint de polyarthrite rhumatoide (67 pieds) ou de rhumatisme psoriasique (2 pieds) avec deformation severe de l’avant pied. L’age moyen au moment de l’intervention etait de 58 ans. Tous les patients souffraient de douleurs liees au chaussage, de metarsalgies ou de difficulte de marche. L’indication chirurgicale etait portee lorsque les mesures conservatrices (chaussage adapte, semelles orthopediques, orthoplasties…) s’averaient insuffisantes. Fonctionnellement le score de Kitaoka preoperatoire s’elevait en moyenne a 36,6. Radiologiquement l’angle metatarso-phalangien preoperatoire moyen du premier rayon etait mesure a 48° (14°-108°). Methode L’intervention consistait en une arthrodese metatarso-phalangienne de l’hallux par voie mediane et une resection des tetes metatarsiennes laterales par voie plantaire. Le realignement et la longueur des rayons lateraux etaient maintenus par interposition de protheses boutons stabilisees par des broches axiales temporaires pendant 6 semaines. L’appui etait progressivement autorise a partir de l’ablation des broches. Resultats Au terme de l’etude, le chaussage et l’aspect esthetique etaient ameliores pour plus de 80 % des patients. Le score de Kitaoka augmente en moyenne de plus de 30 points. La tolerance des protheses boutons a ete excellente et les migrations ont ete rares (moins de 5 %). La correction de l’angle metatarso-phalangien a ete mesuree a 18° (0°-44°). Trois pseudarthroses ont ete notees, dont deux necessitant une reprise chirurgicale. Un retard de cicatrisation a ete observe sur 8 pieds (cicatrice plantaire). Nous ne deplorons qu’une complication thromboembolique et qu’un hematome postoperatoire. Il n’y a pas eu de necrose ischemique d’orteil. Discussion Avec des resultats comparables ou superieurs aux autres series publiees, une excellente tolerance des implants, une augmentation du score fonctionnel de plus de 30 points en moyenne et une amelioration du chaussage pour plus de 80 % des patients l’arthrodese du premier rayon et le realignement des metatarsiens lateraux avec interposition de protheses boutons est pour nous une methode de reference dans le traitement des avants pieds rhumatoides severes.

Pilot Study of Safety and Performance of a Mixture of Calcium Phosphate Granules Combined with Cellulosic-Derived Gel after Tunnel Filling Created during Surgical Treatment of Femoral Head Aseptic Osteonecrosis

The biomaterial studied here is a composite associating a mineral phase of an intimate nanoscale melting of hydroxyapatite and beta tri calcium phosphate and an aqueous phase containing a synthetic polymer derived from cellulose HPMC (hydroxyl propyl methyl cellulose), marketed under name MBCP Gel (FDA approval, Biomatlante manufacturer). The present exploratory study aim was to study the safety of MBCP-gel, and to determine in the osseous healthy area the performance of MBCP gel. We expected to prove bone ingrowth into the osseous cavities created during drilling biopsy of the aseptic osteonecrosis of femoral head. The current results obtained in the first two patients with 1 year follow up demonstrate the resorption and bone ingrowth with trabecular bone architecture in the hole created into the femoral neck.

In Vitro and In Vivo Behavior of Coral Treated by Hydrogen Peroxide, Supercritical Ethanol, or Heat

In this study we focus on the use of coral Porites Lutea and the various treatments used to remove proteins while assessing the impact of the various removal methods on the in vitro and in vivo coral behavior. No significant differences were observed in vitro among all materials. In vivo, no histological differences were observed between BiocoralÒ and samples treated by either hydrogen peroxide or a thermal procedure. The implants made from supercritical fluid treated coral were more resistant to resorption (50% more resistant after one month).