Polyethylene wear in anatomic and reversed shoulder prostheses

Purpose: Polyethylene wear is a recurrent problem in joint arthroplasty. Small debris particles are also associated to inflammation reaction of the surrounding bone, eventually leading to the failure of the bound between the implant and the host bone, and implant loosening. The goal of this study was thus to estimate the volume of polyethylene wear of a reversed prosthesis, and compare it to an anatomic prosthesis, during one year of activities of daily living. Material and Methods: A numerical musculoskeletal model of the glenohumeral joint was used for this comparative study. The reversed (RP) and anatomic (AP) Aequalis prostheses were positioned in the numerical model. Eight levels of abduction were considered. Their daily frequency was estimated from in-vivo recorded data on healthy volunteers during activities of daily living. One year of use was simulated to predict the linear and volumetric wear. The volumetric wear was the difference of volume between the original and worn component. Results: With the AP, the contact pattern on the glenoid surface moved rapidly from the inferior to the superior side during the first 30 degrees of abduction, and then went back to the inferior side. With the RP, the contact pattern on the humeral cup surface remained at the inferior side. Contact pressure was 20 times lower with the RP than with the AP. One year of use produced a maximum linear wear of 0.2 mm with the AP, and 0.13 mm with the RP. However, the volumetric wear was 8.4 mm3 with the AP, but reached 44.6 mm3 with the RP. Conclusion: Polyethylene particles are a matter of concern with AP. Infiltration of these particles within the bone-implant interface can induce a implant loosening. This problem should not be underestimated with RP. It might be associated to a higher level of humeral stem loosening reported with RP. The long term survival of RP might be improved by using a highly cross-linked polyethylene, which has a better abrasion resistance but lower plastic resistance.

What influence do anticoagulants have on oral implant therapy? A systematic review.

OBJECTIVES: This systematic review aims to assess the risks (both thromboembolic and bleeding) of an oral anticoagulation therapy (OAT) patient undergoing implant therapy and to provide a management protocol to patients under OAT undergoing implant therapy. MATERIAL AND METHODS: Medline, Cochrane Data Base of Systematic Reviews, the Cochrane Central Register of Controlled Trials and EMBASE (from 1980 to December 2008) were searched for English-language articles published between 1966 and 2008. This search was completed by a hand research accessing the references cited in all identified publications. RESULTS: Nineteen studies were identified reporting outcomes after oral surgery procedures (mostly dental extractions in patients on OAT following different management protocols and haemostatic therapies). Five studies were randomized-controlled trials (RCTs), 11 were controlled clinical trials (CCTs) and three were prospective case series. The OAT management strategies as well as the protocols during and after surgery were different. This heterogeneity prevented any possible data aggregation and synthesis. The results from these studies are very homogeneous, reporting minor bleeding in very few patients, without a significant difference between the OAT patients who continue with the vitamin K antagonists vs. the patients who stopped this medication before surgery. These post-operative bleeding events were controlled only with local haemostatic measures: tranexamic acid mouthwashes, gelatine sponges and cellulose gauzes's application were effective. Post-operative bleeding did not correlate with the international normalised ratio (INR) status. In none of the studies was a thromboembolic event reported. CONCLUSIONS: OAT patients (INR 2-4) who do not discontinue the AC medication do not have a significantly higher risk of post-operative bleeding than non-OAT patients and they also do not have a higher risk of post-operative bleeding than OAT patients who discontinue the medication. In patients with OAT (INR 2-4) without discontinuation, topical haemostatic agents were effective in preventing post-operative bleeding. OAT discontinuation is not recommended for minor oral surgery, such as single tooth extraction or implant placement, provided that this does not involve autogenous bone grafts, extensive flaps or osteotomy preparations extending outside the bony envelope. Evidence does not support that dental implant placement in patients on OAT is contraindicated.

Utilité de la prophylaxie antibiotique avant un geste dentaire pour tes porteurs de prothèses totales du genou ou de la hanche [Antibiotic prophylaxis before dental procedures in arthroplasty patients]

Antibiotic prophylaxis is commonly prescribed to patients with total arthroplasties before a dental intervention. This attitude is not evidence-based for several reasons: 1) the usual pathogens of prosthetic joint infections are not of oral origin; 2) even if given, systemic antibiotic do not completely suppress the occult bacteraemia occurring during dental intervention and 3) humans may have up to twelve episodes of occult bacteraemia of dental origin per day. Routine antibiotic prophylaxis should be clearly distinguished from the antibiotic treatment required in case of established oral cavity infection. A constant optimal oral and dental hygiene is more important in terms of prevention and should be routinely recommended to every patient carrying a joint arthroplasty.

Retrograde ascending aortic dissection during or after thoracic aortic stent graft placement: insight from the European registry on endovascular aortic repair complications.

BACKGROUND: Single-center reports have identified retrograde ascending aortic dissection (rAAD) as a potentially lethal complication of thoracic endovascular aortic repair (TEVAR). METHODS AND RESULTS: Between 1995 and 2008, 28 centers participating in the European Registry on Endovascular Aortic Repair Complications reported a total of 63 rAAD cases (incidence, 1.33%; 95% CI, 0.75 to 2.40). Eighty-one percent of patients underwent TEVAR for acute (n=26, 54%) or chronic type B dissection (n=13, 27%). Stent grafts with proximal bare springs were used in majority of patients (83%). Only 7 (15%) patients had intraoperative rAAD, with the remaining occurring during the index hospitalization (n=10, 21%) and during follow-up (n=31, 64%). Presenting symptoms included acute chest pain (n=16, 33%), syncope (n=12, 25%), and sudden death (n=9, 19%) whereas one fourth of patients were asymptomatic (n=12, 25%). Most patients underwent emergency (n=25) or elective (n=5) surgical repair. Outcome was fatal in 20 of 48 patients (42%). Causes of rAAD included the stent graft itself (60%), manipulation of guide wires/sheaths (15%), and progression of underlying aortic disease (15%). CONCLUSIONS: The incidence of rAAD was low (1.33%) in the present analysis with high mortality (42%). Patients undergoing TEVAR for type B dissection appeared to be most prone for the occurrence of rAAD. This complication occurred not only during the index hospitalization but after discharge up to 1050 days after TEVAR. Importantly, the majority of rAAD cases were associated with the use of proximal bare spring stent grafts with direct evidence of stent graft-induced injury at surgery or necropsy in half of the patients.

Objective results at 1 year of a new ultracongruent postero-stabilized total knee arthroplasty

Introduction: A new ultra congruent, postero-stabilized total knee arthroplasty (TKA) with a mobile bearing, the FIRST knee prosthesis (Free Insert in Rotation Stabilized in Translation, Symbios SA), was designed and expected to significantly reduce polyethylene wear, to improve the range of motion and the overall stability of the knee while ensuring a physiological ligament balance. Gait analysis has proven to give really objective outcome parameters after lower limb surgery. The goal of our study was to compare the subjective and really objective results of this new TKA with two other widespread models of TKA. Methods: A clinical prospective monocentric cohort study of 100 consecutive patients (47-88 yrs) undergoing a FIRST TKA for primary osteoarthritis is currently being done. Pre- and post-operative follow-ups (6 weeks, 4 months and 1 year) were done with well-recognized subjective evaluations (EQ-5D and WOMAC scores) and semi-objective questionnaires (KSS score and radiography evaluation) as well as with a really objective evaluation using gait parameters from 6 walking trials, performed at different speeds (slow, normal and fast) with an ambulatory gait analysis system (Physilog®, BioAGM CH). The outcomes of the first 32 new TKA after one year of follow-up were compared to the results after 1 year of a randomized controlled clinical trial comparing 29 NexGen® postero-stabilized TKA (Zimmer Inc) with a fixed bearing and 26 NexGen® TKA with a mobile bearing using the same methods. Results: Subjective and semi-objective results were similar for the three types of TKA. As for the really objective parameters, the gait cycle time of the FIRST TKA was statistically significantly shorter at normal speed of walk, as well as double-support periods, as compared to both standard models. The extension (in terms of range of motion when walking) of the operated knee was significantly improved for all three types of walk in favour of the FIRST TKAs compared to both NexGen TKAs. The normal walking speed was significantly higher with faster swing speed and stride lengths for the new TKA. Significantly better coordination scores were observed at normal walking speed for the FIRST TKA as compared to the fixed-bearing TKAs. Conclusion: The FIRST TKAs showed statistically significantly better objective outcomes in terms of gait after one year of follow-up with similar subjective and semi-objective results in comparison with widespread TKA designs. These encouraging short-terms results will have to be confirmed at a 5 years follow-up of the FIRST TKAs.

A new self-expanding aortic stent valve with annular fixation: in vitro haemodynamic assessment.

OBJECTIVE: Balloon-expandable stent valves require flow reduction during implantation (rapid pacing). The present study was designed to compare a self-expanding stent valve with annular fixation versus a balloon-expandable stent valve. METHODS: Implantation of a new self-expanding stent valve with annular fixation (Symetis, Lausanne, Switzerland) was assessed versus balloon-expandable stent valve, in a modified Dynatek Dalta pulse duplicator (sealed port access to the ventricle for transapical route simulation), interfaced with a computer for digital readout, carrying a 25 mm porcine aortic valve. The cardiovascular simulator was programmed to mimic an elderly woman with aortic stenosis: 120/85 mmHg aortic pressure, 60 strokes/min (66.5 ml), 35% systole (2.8 l/min). RESULTS: A total of 450 cardiac cycles was analysed. Stepwise expansion of the self-expanding stent valve with annular fixation (balloon-expandable stent valve) resulted in systolic ventricular increase from 120 to 121 mmHg (126 to 830+/-76 mmHg)*, and left ventricular outflow obstruction with mean transvalvular gradient of 11+/-1.5 mmHg (366+/-202 mmHg)*, systolic aortic pressure dropped distal to the valve from 121 to 64.5+/-2 mmHg (123 to 55+/-30 mmHg) N.S., and output collapsed to 1.9+/-0.06 l/min (0.71+/-0.37 l/min* (before complete obstruction)). No valve migration occurred in either group. (*=p<0.05). CONCLUSIONS: Implantation of this new self-expanding stent valve with annular fixation has little impact on haemodynamics and has the potential for working heart implantation in vivo. Flow reduction (rapid pacing) is not necessary.

Salvage treatment for venous aneurysm complicating vascular access arteriovenous fistula: use of an exoprosthesis to reinforce the vein after aneurysmorrhaphy.

OBJECTIVES: We report a new salvage technique for treating venous aneurysms (VAs) complicating vascular access arteriovenous fistula (AVF) using externally reinforced venous aneurysmorrhaphy. DESIGN: A retrospective study over a 20-month period from a single centre. PATIENTS: Patients presenting to the vascular surgery department, Bordeaux University Hospital for revision of a vascular access AVF were included. METHODS: Reinforced venous aneurysmorrhaphy consisted in removal of redundant vessel wall followed by reinforcement using an external prosthetic graft. Patency, diameter and flow were assessed by duplex ultrasound at 1, 6 and 12 months after salvage. RESULTS: Thirty-eight eligible patients were identified. Five were excluded because VA was associated with central vein stenosis; the remaining 33 underwent salvage. Indications were rapidly expanding or painful VA in seven cases; VA with frequent bleeding or damaged overlying skin in eight; VA in close relation to a stenosis in two; and VA associated with high-flow rate in 16. Cannulation was attempted after 30 days. Mean follow-up time was 12 S.D. 5 months (range: 4-22). Two repaired AVFs failed. Primary 1-year patency was 93%. No aneurysm or infection occurred. Reduction of high flow was successful in 12 of 16 patients. The remaining four required re-operation. CONCLUSIONS: Reinforced venous aneurysmorrhaphy is effective in controlling venous dilation and achieving patency. Reduction of high-flow rates was not always achieved. Further study is needed to evaluate long-term efficacy of this treatment.

Prevalence of complications after the oral rehabilitation with implant-supported hybrid prostheses

Objectives: Assess the main problems referred by the patients and observed by the professionals after the bucodental rehabilitation with an implant-supported hybrid prothesis. Patients and Methods: A retrospective study was carried out in which there were 43 patients included who were visited in the Department of Oral Surgery and Orofacial Implantology of University of Barcelona Dental School for one year. An oral rehabilitation with an implant-supported hybrid prosthesis was made to those patients. The following variables were registered: age, gender, number of inserted implants, type of implant and principal problems produced by the hybrid prosthesis. Results: The rehabilitation with an implant supported hybrid prosthesis was only performed in 43 of 116 cases treated in one year (January, 2006 to January, 2007). They were 26 men and 17 women of ages between 37 and 74 years, being the rate age of 56,5 years. The main complication recorded was the mucositis, associated frequently with a difficulty to carry a correct oral hygiene and to an overextention of the tail of resin of the prosthesis. Other observed problems were the peri-implantitis, the break of the acrylic teeth and the loss of some of the prosthetic screws. Conclusions: The most frequent complication after the laying of an implant supported hybrid prosthesis was the mucositis, associated mainly with a prosthetic tail too long and to the consequent difficulty of carrying a correct oral hygiene. In spite of the high prevalence of observed complications, most of them were mild and resolved on subsequent visits.

Airway stenting with the LT-Mold? for severe glotto-subglottic stenosis or intractable aspiration: experience in 65 cases.

The purpose of this study was to assess the safety and efficacy of stenting in upper airway reconstructions for benign laryngotracheal stenosis (LTS) with a newly designed prosthesis, the LT-Mold?. The LT-Mold and its proper use during open surgery and endoscopy are described, and the experience gathered from a prospectively collected database on 65 patients treated for complex LTS or severe aspiration is reported. This series is compared to the results of other stenting methods. All patients were available for evaluation. In all but one case, the prosthesis was removed at the end of the study. The new prosthesis did not induce any stent-related trauma to the supraglottis, glottis and subglottis. Before adding a distal round-shaped silicone cap to the LT-Mold, granulation tissue was usually seen at the stent-mucosal interface at the tracheostoma level. In 14 cases, there has been a spontaneous extrusion of the prosthesis through the mouth; this problem was solved by fixing the prosthesis through the reinforced portion of the prosthesis at the cap level and by adding one fixation stitch in the supraglottis. We have to document the loss of the silicone cap in three cases. This problem was resolved by designing a new prototype with an integrated cap, glued with a slow hardening silicone glue. Fifty-four (83 %) of 65 patients were decannulated after a mean duration of stenting of 3 months (range 1-12 months). The mean follow-up after decannulation was 23 months (range 1 month to 10 years). The experience gathered with the LT-Mold shows that long-term stenting for complex LTS is safely achieved when the prosthesis is used with its distal integrated silicone cap. The softness and smoothness of the prosthesis with a round-shaped configuration of both extremities help avoid ulceration and granulation tissue formation in the reconstructed airway. Adequate fixation is mandatory to avoid extrusion.

Drawback of aortoplasty for aneurysm of the ascending aorta associated with aortic valve disease.

BACKGROUND: Aortoplasty has been advocated for moderate dilatation of the ascending aorta associated with aortic valve disease. We report our results with this conservative approach. METHODS: Seventeen consecutive patients with unsupported aortoplasty were reviewed. Twelve patients had aortic valve regurgitation and 5 had stenosis. The aortic wall was analyzed histologically in 14 patients. Follow-up was complete, with a mean time of 6 years (range, 2.3 to 10.5 years). RESULTS: Two patients among the 15 hospital survivors died during follow-up of causes unrelated to aortic pathology. Survival at 7 years was 86.7% (+/- 8.8%). Recurring aortic aneurysms developed in 4 patients after a mean time of 63 months, with an event-free survival at 7 years of 41% (+/- 21%). All of these 4 patients had aortic valve regurgitation and cystic medial necrosis. CONCLUSIONS: The recurrence rate of aneurysms after unsupported aortoplasty and aortic valve replacement is high in patients with aortic regurgitation. This strongly suggests that in these patients, the aortic dilatation is related to an underlying wall deficiency, associated with the aortic valve pathology, rather than to the hemodynamic stress imposed by the aortic valve disease.

Prothese totale du genou aujourd'hui: que dire a nos patients? [Total knee arthroplasty today: what should we tell our patients?]

Total knee arthroplasty (TKA) remains the preferred treatment for patients with invalidating osteoarthritis. It allows these patients to find once again a satisfactory quality of life. These results are reflected by the increasing number of interventions performed each year and in always younger patients. The objective of this review of the scientific literature was to determine the long-term quantitatively and qualitatively results of TKA and determine the parameters which could influence the long-term outcome. There does not seem to be any clear arguments in favor of one type of implant or surgical technique. One also notices that TKA in females and older patients seem to have longer lifespan, estimated to approximately 15 years. The most frequent complication remains aseptic loosening followed by infections.

Rehabilitation of orbital cavity after total orbital exenteration using oculofacial prostheses anchored by osseointegrated dental implants posed as a one-step surgical procedure

BACKGROUND: Total orbital exenteration is a radical surgical procedure, which typically involves the removal of the entire contents of the orbit including the periorbita, leaving the patient with a deep orbital deformity and results in devastating cosmetic, functional, and psychological consequences requiring difficult and challenging procedures for oculoplastic surgeons. Oculofacial prostheses retained by endosseous dental implants present an attractive and viable alternative when aesthetic and functional demands are beyond the capacity of local reconstructive efforts. PATIENTS AND METHODS: A 72-year-old woman presenting a malignant melanoma of the right eyelids and a 77-year-old man presenting a sebaceous carcinoma of the left upper eyelid underwent a total exenteration followed by positioning of endosseous implants (Straumann system Dental implants) as an integrated one-step combined surgical procedure. The oculofacial prosthesis was placed after epithelialization of the orbital cavity. RESULTS: The implants were perfectly osseointegrated without any complications, providing sufficient retention of the prostheses. A satisfactory aesthetic outcome has been achieved for both patients. CONCLUSIONS: Oculofacial prostheses anchored by osseointegrated dental implants placed as one-step surgical procedure ensure an adequate aesthetic result as well as a considerably decreased rehabilitation time and present a satisfactory solution when reconstruction is not a suitable option.

What treatment for periprosthetic shoulder infection? Results from a multicentre retrospective series.

PURPOSE: Controversy still exists as to the best surgical treatment for periprosthetic shoulder infections. The aim of this multi-institutional study was to review a continuous retrospective series of patients treated in four European centres and to assess the respective eradication rate of various treatment approaches. METHODS: Forty-four patients were available for this retrospective follow-up evaluation. Functional and clinical evaluation of treatment for infection was performed using the Constant-Murley score, visual analogue scale and patient satisfaction Neer score. Erythrocyte sedimentation rate, serum leucocyte count and C-reactive protein were measured and shoulder X-ray examination performed prior to surgery and at the latest follow-up. RESULTS: At a mean follow-up of 41 months (range 24-98), 42 of 44 patients (95.5%) showed no signs of infection recurrence/persistence. Comparable eradication rates were observed after resection arthroplasty (100%; 6/6), two-stage revision (17/17) or permanent antibiotic-loaded spacer implant (93.3%; 14/15). No patient was treated by one-stage revision. On average, both functional and pain scores improved significantly; the worst joint function was observed after resection arthroplasty. CONCLUSIONS: This retrospective analysis conducted on the largest published series of patients to date shows comparable infection eradication rates after two-stage revision, resection arthroplasty or permanent spacer implant for the treatment of septic shoulder prosthesis.

A randomised controlled clinical trial and gait analysis of fixed- and mobile-bearing total knee replacements with a five-year follow-up.

This study compared the outcome of total knee replacement (TKR) in adult patients with fixed- and mobile-bearing prostheses during the first post-operative year and at five years' follow-up, using gait parameters as a new objective measure. This double-blind randomised controlled clinical trial included 55 patients with mobile-bearing (n = 26) and fixed-bearing (n = 29) prostheses of the same design, evaluated pre-operatively and post-operatively at six weeks, three months, six months, one year and five years. Each participant undertook two walking trials of 30 m and completed the EuroQol questionnaire, Western Ontario and McMaster Universities osteoarthritis index, Knee Society score, and visual analogue scales for pain and stiffness. Gait analysis was performed using five miniature angular rate sensors mounted on the trunk (sacrum), each thigh and calf. The study population was divided into two groups according to age (≤ 70 years versus > 70 years). Improvements in most gait parameters at five years' follow-up were greater for fixed-bearing TKRs in older patients (> 70 years), and greater for mobile-bearing TKRs in younger patients (≤ 70 years). These findings should be confirmed by an extended age controlled study, as the ideal choice of prosthesis might depend on the age of the patient at the time of surgery.

Evaluation gériatrique des patients agés candidats a un remplacement valvulaire aortique percutané [Geriatric assessment in old patients candidate to transcatheter aortic implantation].

Aortic stenosis mostly occurs among old-old patients. Once symptoms appear, prognosis is guarded, with 2-year mortality as high as 50%. Transcatheter Aortic Valve Implantation (TAVI) is a new therapeutic option in patients at very high surgical risk, who are mostly older persons. However, TAVI is associated with some complications, and patient selection remains a challenge. Comprehensive geriatric assessment (CGA) identifies patients with medical and functional problems likely to affect the TAVI post-operative course. Collaboration between cardiologists and geriatricians will likely become a standard approach to enhance the assessment of these frail patients and identify those most likely to benefit from TAVI.