Olivier Guyen

The 2009 Frank Stinchfield Award: “Hip Squeaking”: A Biomechanical Study of Ceramic-on-ceramic Bearing Surfaces

We designed and implemented an in vitro bench test to simulate and identify potential biomechanical causes for hip squeaking with alumina ceramic-on-ceramic bearing surfaces. All bearings were third-generation alumina ceramic with a 32-mm head coupled with a 56-mm acetabular component with a 32-mm ceramic insert. Conditions for testing were normal gait, high load, stripe wear, stripe wear in extreme load, metal transfer, edge wear with extreme load, and microfracture. Each condition was tested two times in dry conditions and two times in a lubricated condition with 25% bovine serum. Squeaking was reproduced in all dry conditions. It occurred quickly with high load, stripe wear, or metal transfer. Once squeaking occurred, it did not stop. Squeaking disappeared for all conditions when a small amount of lubricant was introduced. In lubricated conditions, squeaking was only reproduced for the material transfer condition. Our observations suggest squeaking is a problem of ceramic-ceramic lubrication and that this noise occurs when the film fluid between two surfaces is disrupted. Material (metal) transfer was the only condition that led to squeaking in a lubricated situation.

Nine years follow-up of 100 ceramic-on-ceramic total hip arthroplasty

The aim of this study was to evaluate the first 100 cementless ceramic-on-ceramic total hip arthroplasty (THA) performed at our institution with more than nine years of follow-up. Clinical evaluation was performed using Harris hip score. Radiological evaluation was performed by two surgeons. Four patients were lost to follow-up. Harris hip score significantly improved at latest follow-up. Radiological analysis showed calcar osteolysis for 75 patients and one cup loosening. One patient required a revision five years postoperatively for cup loosening. Based on these results and the routine use of a navigation system to optimise positioning of the implants, we advocate the use of uncemented hydroxyapatite coated ceramic-on-ceramic THA in young and active patients in our current practice.

Cementation of a dual-mobility acetabular component into a well-fixed metal shell during revision total hip arthroplasty: A biomechanical validation†

Cementation of polyethylene (PE) liners into well‐fixed metal shells has become a popular option during revision total hip arthroplasty (THA) particularly for older and frail patients. Although dramatic results were reported with dual‐mobility acetabular components to manage hip instability during revision THA, no study evaluated the fixation strength of the cementation of dual‐mobility components into well‐fixed metal shells. Eight dual‐mobility and eight all‐PE components were cemented into a metal shell with a uniform 2‐ to 3‐mm cement mantle. The cemented fixation strength was evaluated using lever‐out and torsion testing. The interface at which failure occurred was determined. Lever‐out testing showed that dual‐mobility components failed at significantly higher maximum moment than the all‐PE components. No direct comparison could be performed with torsion testing due to early failure of the all‐PE component itself before failure of the cement fixation. However, the maximum moments measured were dramatically higher than the in vivo frictional moments classically reported in THA. In addition, failure was always observed at the metal shell/cement interface whenever it did occur. In conclusion, a dual‐mobility acetabular component cemented into a well‐fixed metal shell could constitute a biomechanically acceptable alternative to acetabular shell removal or PE liner cementation while simultaneously preventing instability of the THA revision. Clinical studies are warranted.

Arthroplastie totale de hanche chez l’insuffisant rénal chronique greffé ou dialysé

Purpose of the study Total hip arthroplasty (THA) is generally proposed for renal transplant patients with invalidating hip disease. For patients on chronic dialysis, the few published series report a higher rate of complications. These patients are considered more vulnerable. We report the results of a retrospective mid-term analysis of 28 renal failure patients (37 hips) with THA comparing renal transplant recipients with chronic dialysis patients.Resume Le but de l’etude etait d’evaluer de maniere retrospective la morbidite, la mortalite et les resultats a moyen terme de l’arthroplastie totale de hanche chez les patients souffrants d’insuffisance renale en dialyse et/ou greffes. De janvier 1993 a janvier 2004, 37 protheses totales de hanche ont ete implantees chez 28 patients (14 dialyses et 14 greffes). L’osteonecrose aseptique etait l’etiologie principale. Trente et une cupules et 29 tiges implantees etaient non cimentees. Tous les patients vivants ont ete revus avec un recul moyen de 6 ans (24 mois-12 ans). Les complications precoces et secondaires ont ete recherchees. Les resultats cliniques ont ete evalues par les scores de Merle d’Aubigne et de Harris. Les complications post-operatoires precoces etaient representees chez les patients dialyses par trois thromboses veineuses profondes, quatre embolies pulmonaires, deux hematomes et une infection. Chez les greffes renaux, nous avons observe deux luxations precoces et trois pneumopathies. Quatre deces sont survenus, tous chez des patients dialyses. Le score PMA moyen preoperatoire etait de 7,6 chez les patients dialyses et de 10,3 chez les patients greffes ; progressant a la revision respectivement a 14,2 et 15,7. Les radiographies ne retrouvaient aucun signe de descellement, aucune usure du polyethylene et l’absence d’ossifications ectopiques. L’arthroplastie totale de la hanche chez les patients greffes est une intervention fiable avec de bons resultats a moyen terme et une morbidite proche de celle de la population generale avec possibilite d’utiliser des implants non scelles. En revanche, chez les patients dialyses une morbidite perioperatoire elevee etait retrouvee. Il est necessaire de favoriser le traitement chirurgical apres la greffe renale plutot que sur un patient en dialyse. En cas de chirurgie, celle-ci doit etre effectuee au sein d’une equipe pluridisciplinaire medico-chirurgicale.

Désarthrodèse-prothèse de hanche pour séquelle d’arthrite septique: À propos d’une série de 17 cas à 6 ans de recul

PURPOSE OF THE STUDY Revision total hip arthroplasty (THA) after hip arthrodesis is an uncommon and challenging operation. The task would appear to be even more difficult if the arthrodesis was performed because of septic arthritis due to the theoretical risk of recurrent infection. We report our fifteen-year experience. MATERIAL AND METHODS This retrospective study concerned 17 procedures performed in 17 patients (11 women, 6 men) between 1988 and 2003 on 5 right and 12 left hips. All of the patients had arthrodesis for sepsis: eight subsequent to tuberculosis and nine subsequent to septic arthritis (Staphylococcus aureus). We examined the impact of the initial arthrodesis (surgical technique, position, leg length) on neighboring joints and indications for de-fusion. Mean age was 53 years (range 32-74) and on average, the patients had a fixed hip for 36 years (range 7-59). Mean follow-up was six years (range 11 months to 15 years). Revision surgery was performed via a posterolateral approach for 12 hips (nine trochanterotomies) and via an anterolateral approach for five hips for implantation of nine cemented implants, six press fit implants, and two hybrid implants (cemented cup and press fit stem). Clinical assessment at last follow-up noted pain, walking capacity and joint motion. Leg length discrepancy was measured and complications were noted. RESULTS The position of the original arthrodesis was considered satisfactory (flexion 20 degrees , adduction 0-10 degrees , external rotation 0-20 degrees ) for eight hips; leg length discrepancy was 4 cm (2-8 cm). Neighboring joints involved concerned the lumbar spine in 15 patients, the ipsilateral knee in ten patients, the contralateral knee in eight and the contralateral hip in six. The decision to remove the arthrodesis was based on functional needs related to lumbar pain (n=6), the homolateral knee (n=10, limping and leg length discrepancy), or an operation on the ipsilateral knee. After surgery, 14 hips (83%) were free of pain with improvement of the lumbar pain and pain of the homolateral knee. Six patients walked without support but 16 still had a limp. Flexion was 78 degrees . Leg length discrepancy was 2.5 cm on average and seven patients had balanced limbs. The postoperative period was uneventful for 14 of 17 patients (one paresia of the common fibular nerve, one femoral phlebitis, one early infection). Six late complications were noted: nonunion of the greater trochanter (n=2), recurrent ankylosis (n=1) and loosening (n=3). DISCUSSION AND CONCLUSION An earlier history of infection does not appear to be a contraindication for implantation of a total hip arthroplasty after hip arthrodesis. Despite the long recovery period and the modest gain in joint motion, 80% of patients were satisfied after having had a blocked hip for 36 years on average.Resume Nous rapportons le resultat des desarthrodese-protheses pour sequelles d’arthrite septique pratiquees sur une periode de 15 ans, cette intervention presentant un risque theorique de recidive de l’infection ancienne. Il s’agissait d’une etude retrospective concernant 17 patients (11 femmes, 6 hommes). Toutes les arthrodeses avaient ete effectuees pour des raisons septiques (8 coxalgies, 9 arthrites septiques a germes pyogenes). La technique d’arthrodese etait dans 10 cas intra-articulaire, et dans 7 cas extra-articulaire. L’âge moyen, au moment de la desarthrodese, etait de 53 ans (32-74). La position de l’arthrodese initiale etait jugee satisfaisante pour seulement 8 cas. L’inegalite de longueur preoperatoire etait de 4 cm (2 a 8). L’atteinte d’une articulation de proximite concernait le rachis lombaire (15 cas), le genou ipsilateral (10 cas), le genou controlateral (8 cas) et la hanche controlaterale (6 cas). L’anciennete de l’arthrodese etait de 36 ans (7-59). Cinq abords anterolateraux et 12 abords posterolateraux (9 trochanterotomies) ont ete realises. Les implants utilises etaient : 9 implants cimentes, 6 implants sans ciment et 2 implants hybrides (cupule cimentee et tige sans ciment). Le recul moyen etait de 6 ans (11 mois - 15 ans). Au recul, 14 hanches operees (83 %) etaient indolores avec amelioration des douleurs lombaires et du genou ipsilateral. La marche s’effectuait sans canne pour 6 patients, mais 16 patients conservaient une boiterie. La flexion moyenne etait de 78 . L’inegalite de longueur residuelle etait de 2,5 cm avec 7 patients equilibres. Les suites etaient simples pour 14 patients (1 paresie du nerf fibulaire commun, 1 phlebite femorale, 1 infection precoce). Six complications tardives etaient deplorees : 2 pseudarthroses du grand trochanter, 1 recidive d’ankylose et 3 descellements. Un antecedent septique ancien ne semble pas contre-indiquer l’implantation d’une prothese totale de hanche pour une desarthrodese. Malgre une recuperation longue et un gain de mobilite modeste, on releve 80 % de satisfaction, concernant ces hanches bloquees depuis en moyenne 36 ans.

Le fibrome desmoplastique ou fibrome desmoïde osseux : À propos de 2 nouveaux cas d'une tumeur osseuse rare

Desmoplastic fibroma or desmoid bone tumor is a rare tumor described for the first time by Jaffe in 1958. It accounts for 0.1 to 0.3% of all benign bone tumors. To date, about 150 cases involving the locomotor system have been reported. Histology is required for certain diagnosis of desmoplastic fibroma. The tumor is composed of sparse fibroblasts in a rich background of collagen fibers, a histological presentation exactly the same as soft tissue desmoid fibroma. We report two new cases of desmoplastic fibroma of the locomotor system. The observations illustrate the radiological diagnosis. MRI was used to search for local extension in bone or soft tissues. Biopsy is necessary to confirm the diagnosis. The histological presentation may be difficult to recognized and distinguish from low grade fibrosarcoma. After treatment, the rate of local recurrence is high in the event of partial resection. Surgery is the optimal treatment, with tumor resection as wide as possible depending on the localization.

Dual mobility cups provide biomechanical advantages in situations at risk for dislocation: a finite element analysis

PurposeConstrained devices, standard implants with large heads, and dual mobility systems have become popular options to manage instability after total hip arthroplasty (THA). Clinical results with these options have shown variable success rates and significant higher rates of aseptic loosening and mechanical failures with constrained implants. Literature suggests potential advantages of dual mobility, however little is known about its biomechanics. We present a comparative biomechanical study of a standard implant, a constrained implant, and a dual mobility system.MethodsA finite element analysis was developed to assess and compare these acetabular options with regard to the range of motion (ROM) to impingement, the angle of dislocation, the resistive torque, the volume of polyethylene (PE) with a stress above 80% of the elastic limit, and the interfacial cup/bone stress.ResultsDual mobility implants provided the greatest ROM to impingement and allowed delaying subluxation and dislocation when compared to standard and constrained implants. Dual mobility also demonstrated the lowest resistive torque at subluxation while the constrained implant provided the greatest one. The lowest critical PE volume was observed with the dual mobility implant, and the highest stress at the interfaces was observed with the constrained implant.ConclusionThis study highlights the biomechanical advantages of dual mobility systems over constrained and standard implants, and is supported by the clinical results reported. Therefore, the use of dual mobility systems in situations at risk for instability should be advocated and constrained implants should be restricted to salvage situations.

270 Navigation et prothèse totale de la hanche ; analyse d’une série de 130 PTH

Introduction Les conflits intra-prothetiques sont a l’origine des problemes d’instabilite, d’usure et de descellement. Nous presentons notre experience de l’utilisation d’un logiciel de navigation pour prothese totale de la hanche permettant d’optimiser le positionnement et le fonctionnement relatif des implants prothetiques. Materiel et methode Nous avons etudie de facon prospective et continue 130 protheses totales de hanche implantees chez 128 patients de septembre 2005 a fevrier 2007. Les indications etaient 93 coxarthroses, 23 necroses de la tete femorale et 14 arthrites inflammatoires. Les patients etaient 68 hommes (58 ans en moyenne) et de 60 femmes (60 ans en moyenne). Les implants utilises etaient sans ciment recouverts d’hydroxyapatite, avec un couple metal/polyethylene dans 16 cas et ceramique/ceramique dans 114 cas. La technique chirurgicale naviguee etait basee sur l’acquisition peroperatoire des structures osteoarticulaires et sur un referentiel fonctionnel prenant en compte la hanche en position neutre, simulant la position debout. Nous avons etudie les resultats a court terme de cette technique naviguee concernant : la morbidite propre a la navigation, le positionnement radiologique des implants acetabulaires et la lateralisation ou medialisation globale du membre et sa longueur. Resultats La longueur du membre opere etait restituee de facon satisfaisante dans 85 % des cas (ILMI Discussion et conclusion Il s’agit d’un systeme de navigation permettant de s’affranchir du plan anatomique pelvien anterieur. Cette navigation nous parait reellement fonctionnelle, liant la cupule au femur dans un cone de mobilite stable et sans conflit intra-prothetique. Cette technique nous a permis de reproduire la programmation preoperatoire de facon fiable. Il ne nous semble pas exister de position « standard » de l’implant acetabulaire : la position de l’implant acetabulaire est a adapter a l’anatomie fonctionnelle propre de chaque patient et egalement au positionnement de l’implant femoral. Ceci permet d’optimiser la stabilite et le fonctionnement du couple prothetique. La simulation de la position du membre inferieur patient debout est le point-cle du systeme. Elle reste perfectible car on ne connait pas l’impact de la liberation de la hanche sur la position erigee notamment dans le plan sagittal, au niveau du complexe lombopelvi-femoral.

Infection aspergillaire et faux anévrisme mycotique fémoral au cours d’un descellement de prothèse totale de hanche avec migration intra-pelvienne de l’implant acétabulaire

We report a case of Aspergillus fumigatus infection of a total hip arthroplasty. This rare infection was demonstrated at surgical revision of a loosened prosthesis with migration of the cup into the pelvis associated with a false aneurysm of the femoral artery. A vascular time was required before the orthopedic revision. This case illustrates the importance of the preoperative work-up in the event of cup migration. The double approach was required in our patient to control and repair the vascular structures. The difficult treatment of Aspergillus fumigatus is also discussed.We report a case of Aspergillus fumigatus infection of a total hip arthroplasty. This rare infection was demonstrated at surgical revision of a loosened prosthesis with migration of the cup into the pelvis associated with a false aneurysm of the femoral artery. A vascular time was required before the orthopedic revision. This case illustrates the importance of the preoperative work-up in the event of cup migration. The double approach was required in our patient to control and repair the vascular structures. The difficult treatment of Aspergillus fumigatus is also discussed.

Chronic Propionibacterium acnes prosthesis joint infection manifesting as a large abscess with gas, without prosthesis loosening.

A 78-year-old woman with diabetes, hypertension and severe omarthrosis, had a left total shoulder arthroplasty in May 2010. In September 2010, the patient developed axillar abscess, without fever or pain, which was incised. Propionibacterium acnes grew in cultures and the patient received amoxicillin-clavulanate for 10 days. In 2011, it reoccurred, with abscess formation that gradually increased in size during several weeks and reached 5×8 cm in diameter (figure 1A). C reactive protein was elevated (94 mg/L), but the patient did not have fever. X-ray examination did not show prosthesis loosening, but a distal cortical thickening of …