Mariano Fernandez-Fairen

Anterior Cervical Fusion With Tantalum Implant : A Prospective Randomized Controlled Study

Study Design. A prospective randomized controlled study was carried out. Objective. To determine the effectiveness and safety of a tantalum implant in achieving anterior cervical fusion following 1-level discectomy as treatment of degenerative cervical disc disease with radiculopathy. Summary of Background Data. The gold standard for the treatment of degenerative cervical disc disease could not be already identified. The morbidity of autologous graft and plating, and the doubt about the mechanical efficacy of plate fixation and the clinical benefits in 1-level fusion have promoted the use of other constructs. Methods. Sixty-one patients were randomized to anterior cervical discectomy and fusion with interbody implant of tantalum (n = 28) or by means of autologous iliac bone graft and plating (n = 33). Fusion rate and segmental height and alignment were blind assessed by radiographs by 2 independent reviewers. Clinical status was evaluated using pain visual analogue scale, the Neck Disability Index, and the Zung Depression Scale. Patient’s subjective satisfaction was recorded. Complications and operative parameters were also taken into account. Results. With an endpoint of 24 months, radiologic and clinical outcomes were similar for both treatments without significant difference. The safety of fusion with tantalum implant was obvious, based on the analysis of complications. Complication rate was considerably higher for the autologous graft plus plating procedure than for implant tantalum (P < 0.005). Conclusion. The efficacy to achieve fusion after 1-level anterior cervical discectomy, with a good radiologic and clinical outcome, using tantalum implant is equivalent to that of autologous graft and anterior plate, being safer as avoids donor-site graft harvesting and plating complications.

Aging of Retrieved Zirconia Femoral Heads

Yttria-stabilized tetragonal zirconia may undergo extensive transformation to the monoclinic phase under mechanical and/or hydrothermal stress, with degradation of mechanical and tribologic properties. We hypothesized progressive phase transformation of zirconia in service in vivo is directly related to the time of implantation and to patient-related factors. The subsequent decrease in fracture toughness and increase in surface roughness and wear are related to the increased monoclinic content. We performed a study on 47 yttria-stabilized tetragonal zirconia femoral heads retrieved from failed total hip arthroplasties after 2 to 10 years implantation. Age, weight, and activity of the patients were retrieved from clinical records. Monoclinic content, fracture toughness, surface roughness, and wear were measured. Strong correlations were found between monoclinic content in the weightbearing surface and time of implantation (r = 0.97) and between increase in monoclinic content and decrease in fracture toughness (r = −0.92), increase in surface roughness (r = 0.88), and increase in surface wear (r = 0.89). No correlation was observed between the increase in monoclinic content and the age, weight, or activity of the patients. Aging of zirconia in vivo is then a function of time in service, and the loss of surface properties is caused by the corresponding increase in monoclinic content. Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Is anterior cervical fusion with a porous tantalum implant a cost-effective method to treat cervical disc disease with radiculopathy?

Study Design. Retrospective cost-effectiveness analysis. Objective. To determine the relative cost-effectiveness of anterior cervical discectomy with fusion (ACDF) using a porous tantalum implant compared with autograft with plating, for single-level cervical disc disease with radiculopathy. Summary of Background Data. ACDF with autograft as an interbody spacer is a generally accepted method to treat degenerated cervical discs with radiculopathy. Concerns about donor site morbidity and the structural characteristics of autograft stimulated investigations of alternative materials. Techniques may differ in their operative risks, complications, outcomes, and resource use. Methods. A retrospective review of clinical outcomes and total cost of illness for 5 years postsurgery was performed for 61 consecutive patients enrolled for this study. Twenty-eight patients were treated with single-level ACDF using either a stand-alone, porous tantalum implant, without graft inside the implant, and 33 patients received autograft and plating. A cost-effectiveness analysis comparing the 2 ACDF treatment methods was conducted. This article reports clinical assessments, quality adjusted life years gained, and an incremental cost-effectiveness ratio analysis. Results. Patients in both cohorts reported improved clinical outcomes, including neck disability index, visual analogue scale, Short-Form 36, Odoms clinical assessment, and patient satisfaction at 5 years postindex surgery. The mean cost of illness for the study period, including preoperative through 5 years postoperative assessments, was 6806 &OV0556; per patient treated with tantalum and 10,143 &OV0556; per patient receiving autograft and plate. Quality-adjusted life years (QALY) gained were 9.41 and 7.14 for the tantalum and control cohorts, respectively. The cost per QALY for the tantalum group was 723 &OV0556; and 1420 &OV0556; for the control group. The incremental cost-effectiveness ratio of ACDF with a porous tantalum implant compared with ACDF with autograft and plate was −1473 &OV0556; per patient per year for the duration of this study. Conclusion. This cost-effectiveness analysis reports favorable results for ACDF procedures utilizing a tantalum implant. The data reported suggest that using porous tantalum as a stand-alone device is less costly and more effective than autograft and plate in ACDF procedures.

Bioactive macroporous titanium implants highly interconnected.

Intervertebral implants should be designed with low load requirements, high friction coefficient and low elastic modulus in order to avoid the stress shielding effect on bone. Furthermore, the presence of a highly interconnected porous structure allows stimulating bone in-growth and enhancing implant-bone fixation. The aim of this study was to obtain bioactive porous titanium implants with highly interconnected pores with a total porosity of approximately 57 %. Porous Titanium implants were produced by powder sintering route using the space holder technique with a binder phase and were then evaluated in an in vivo study. The size of the interconnection diameter between the macropores was about 210 μm in order to guarantee bone in-growth through osteblastic cell penetration. Surface roughness and mechanical properties were analyzed. Stiffness was reduced as a result of the powder sintering technique which allowed the formation of a porous network. Compression and fatigue tests exhibited suitable properties in order to guarantee a proper compromise between mechanical properties and pore interconnectivity. Bioactivity treatment effect in novel sintered porous titanium materials was studied by thermo-chemical treatments and were compared with the same material that had undergone different bioactive treatments. Bioactive thermo-chemical treatment was confirmed by the presence of sodium titanates on the surface of the implants as well as inside the porous network. Raman spectroscopy results suggested that the identified titanate structures would enhance in vivo apatite formation by promoting ion exchange for the apatite formation process. In vivo results demonstrated that the bioactive titanium achieved over 75 % tissue colonization compared to the 40 % value for the untreated titanium.

Analysis of tantalum implants used for avascular necrosis of the femoral head: a review of five retrieved specimens

Aim The effective results shown in the porous systems of tantalum employed for the use of osseointegrates has been demonstrated by means of animal experimentation. However, there is a total lack of any research studies on the osseointegration of tantalum implants from retrieval of the same after a period of time whereby the material had been implanted within the human body. Materials and Methods For this study, five rod implants used for the treatment of avascular necrosis of the femoral head were retrieved following collapse of the femoral head and conversion to total hip arthroplasty. The time of implantation ranged between six weeks and twenty months. Results Observation during this study has confirmed the effectiveness of osseointegration within this period of time. New bone was observed around and within the porous system of the on rod devices at retrieval date. The bone ingrowth, however, proved to be slower and less intense than that resulting within animal species during the first few months after implantation. Conclusions The results obtained in the quantitative assessment of this process proved to be similar to those results achieved by other authors in previous experimental work studies.

Case Report: Floating-clavicle from the 17th Century: The Oldest Case?

BackgroundDislocation of both ends of the clavicle is a rare traumatic lesion and the mechanism of the lesion is usually related to major trauma. The first case was described in 1831.Case DescriptionWe present the oldest referenced case of this alteration. The skeleton studied belonged to an old woman buried inside the Sant Pere de Madrona Church in Berga (Barcelona/Spain) and its dating indicated it corresponded to the end of the 17th century. There was a pseudarthrosis between the clavicle and coracoid ligament; when the bones were reconstructed by pseudarthrosis both ends of the clavicle appeared dislocated.Literature ReviewBipolar dislocation of both ends of the clavicle, or “floating-clavicle”, is a rare injury. Since 1831 when this type of injury was first reported, approximately 40 cases have been published. No archaeological case has been published.Clinical RelevanceDespite experiencing bipolar dislocation of both ends of the clavicle, or floating-clavicle, it is possible to have acceptable function of the arm as suggested by the anthropologic parameters analyzed here. The head of the humerus of the affected shoulder shows no abnormalities and the contralateral glenoid cavity shows severe osteochondritis of the anteroinferior side.

Greater trochanteric pain syndrome and gluteus medius and minimus tendinosis: nonsurgical treatment

Greater trochanteric pain syndrome (GTPS) affects 10-25% of people in developed countries. The underlying etiology for GTPS is most commonly the tendinosis or a tendon tear of the gluteus medius, minimus or both at the greater trochanter; the inflammation of the tendon is not a major feature. We critically evaluated conservative treatment, for which we reviewed 76 publications, grading them according to four levels of evidence. We identified a wide variety of conservative treatment options: home therapy (insoles, walking sticks/crutches, orthotic devices, stretching exercises and preventive measures); physiotherapy (massage and stretching exercises); infiltrations (corticosteroids and local anesthetics); image-guided infiltrations (fluoroscopy and ultrasound); shockwave therapy; platelet-rich plasma injection; and drug therapy. Severe complications associated with infiltrations are extremely rare, as are those associated with shockwave therapy. The most effective treatments were infiltrations with corticosteroids and shockwave therapy. We propose a graded treatment schedule for patients with GTPS.

Two Different Strategies to Enhance Osseointegration in Porous Titanium: Inorganic Thermo-Chemical Treatment Versus Organic Coating by Peptide Adsorption

In this study, highly-interconnected porous titanium implants were produced by powder sintering with different porous diameters and open interconnectivity. The actual foams were produced using high cost technologies: Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), and spark plasma sintering, and the porosity and/or interconnection was not optimized. The aim was to generate a bioactive surface on foams using two different strategies, based on inorganic thermo-chemical treatment and organic coating by peptide adsorption, to enhance osseointegration. Porosity was produced using NaCl as a space holder and polyethyleneglicol as a binder phase. Static and fatigue tests were performed in order to determine mechanical behaviors. Surface bioactivation was performed using a thermo-chemical treatment or by chemical adsorption with peptides. Osteoblast-like cells were cultured and cytotoxicity was measured. Bioactivated scaffolds and a control were implanted in the tibiae of rabbits. Histomorphometric evaluation was performed at 4 weeks after implantation. Interconnected porosity was 53% with an average diameter of 210 µm and an elastic modulus of around 1 GPa with good mechanical properties. The samples presented cell survival values close to 100% of viability. Newly formed bone was observed inside macropores, through interconnected porosity, and on the implant surface. Successful bone colonization of inner structure (40%) suggested good osteoconductive capability of the implant. Bioactivated foams showed better results than non-treated ones, suggesting both bioactivation strategies induce osteointegration capability.

Microstructure and Surface Damage in Retrieved Metal-on-Metal Hip Arthroplasties

BACKGROUND Besides promising results of metal-on-metal (MOM) hip arthroplasty (HA), frequent failures have been reported even in the short term. Many host, surgical, design, metallurgical, and processing factors have been evoked in the base of these events. We have tried to characterize and to evaluate metallurgical and processing features present in this type of implants. METHODS The acetabular and femoral components of 20 MOM HAs collected from a multicenter retrieval program were examined. All the specimens were inspected with naked eye, with confocal microscopy and vertical scanning interferometry, scanning electron microscopy, back-scattered electron imaging, and energy-dispersive X-ray spectroscopy, in 25 zones of each articular component. RESULTS Gas pores, shrinkage voids and holes of detached carbides, carbides on surface, embedded particles, scratches and marks of wear, surface discoloration, surface deposits, and tribochemical reaction layers were widely dispersed through a substantial percentage of the total bearing surface in all the implanted components. Surface cup and head voids, and cup scratches showed significant correlation with the clearance of pair. A higher surface damage of the cup and head was observed mainly in the low clearance prostheses. There was no other significant correlation or difference in the incidence and importance of any of these defects between resurfacing hip arthroplasties and total hip arthroplasties, or according to the pair diameter. CONCLUSION Some metallurgical features and surface damage were significantly present in the retrieved implants of MoM HAs. It would be desirable to improve the structure and metallurgical characteristics of these implants to avoid those effects and optimize their performance.

CORR Insights®: Does Surface Topography Play a Role in Taper Damage in Head-neck Modular Junctions?

H ead-neck modularity is a universally accepted option in hip arthroplasty, and it has worked extremely well in millions of cases over the years. But there is also a large body of evidence that modularity is a source of metallurgical problems including fretting corrosion and wear, producing particles that can potentially lead to clinical problems [1, 8]. There is a lack of knowledge about the particles produced by hip replacements, and about their possible causes and effects; however, we are concerned about corrosion at the trunniontaper interface observed in the retrieved modular hip prostheses, and elevations of serum metal levels on laboratory testing. Although the precise ion levels and imaging findings that should be considered severe enough to trigger clinical interventions remain controversial, the fact that these findings have the potential to cause harm seems clear, even if the true incidence of these problems remains unknown [3, 5, 7, 9]. This should be a warning call to the orthopaedic community. Where Do We Need To Go?