Hybrid Implants Research Articles

Bone height changes around hybrid implants in three implant retained mandibular Overdentures

Objective: The purpose of this RCL was to evaluate bone height changes around hybrid implants in three implant- retained mandibular overdenture with locator attachment.Materials & Methods: Ten completely edentulous male patients were enrolled in this study. Preoperative Cone beam computed tomography (CBCT) had been made to evaluate bone height & density in areas for implant installation. Patients had received three hybrid implants installed in midline & mandibular canine areas following flapless technique. Implants were early loaded; two weeks after implant installation. Overdentures were functionally fitted onto the locator attachment of the hybrid implants by direct pick-up technique.Evaluation: Bone height changes were evaluated with the aid of CBCT at the time of implants’ loading, six months and twelve months later. Mesial & distal crestal bone heights were calculated from reconstructed corrected sagittal views.Results: The results had revealed that there was no significant difference in peri-implant bone level throughout the follow-up periods on comparing the three implant sites. However, there was slightly higher bone resorption around the distal implants than the midline ones.Conclusions Three implant retained overdentures with locator attachments may preserve peri-implant bone in the anterior mandibular area. Midline implant in three implant overdentures may not be subjected to more stresses than the two distal implants

Prospective Multicenter Clinical Cohort Study of a Novel Macro Hybrid Implant in Maxillary Anterior Postextraction Sockets: 1-Year Results

A prospective cohort clinical study was performed to evaluate the concept and design of a novel macro hybrid implant placed into maxillary anterior postextraction sockets. Thirty-three patients with an equal number of hybrid implants were used to replace nonrestorable single anterior teeth with immediate tooth replacement therapy (immediate implant placement and immediate provisional restoration). The macro features of this hybrid implant are unique in geometry, as it combines two different shapes-a cylindrical coronal and tapered apical portion-into a singular body design, each comprising roughly half of the implant length. The hybrid design of this platform-switched implant also has a subcrestal angle correction, or Co-Axis feature, that facilitates screw-retained restorations. Mean implant survival at 1 year relative to primary stability, labial bone plate thickness with socket grafting at two reference points (L1 and L2), tooth-to-implant interproximal bone crest thickness, and pink esthetic score (PES) were evaluated. A mean insertion torque value of 65 Ncm (range 45 to 100 Ncm) was reached with the use of the tapered apical half of the implant body. No implants failed during an average healing period of 1 year. A labial plate dimension between 1.8 and 2.1 mm was attained immediately posttreatment and remained stable over time. A tooth-to-implant interdental bone crest distance and dimension of 2.3 to 2.6 mm was reached; it was also sustained at the 1-year follow-up. The average PES was 12.5 (range 9.0 to 14.0), with nearly 90% of treated sites with an "almost perfect" score. This macro hybrid implant in concept and design may be useful in immediate tooth replacement therapy of maxillary anterior postextraction sockets to achieve successful implant survival and esthetic outcomes, specifically labial plate and papilla preservation without midfacial or interdental tissue loss and discoloration.

Cochlear implant histopathology.

The microscopic examination of fifty-five serially sectioned implanted temporal bones has provided insight into what is being stimulated; and the changes that are the result of the insertion and presence of the implant. The ganglion cell bodies (neurons) are structures being stimulated (two laboratories have reported an inverse relationship of the number of neurons and performance). Insertion through the round window, verses a cochleostomy, produces the least fibrosis and new bone. Fibrosis and new bone do not affect the implant function unless they form in the scala vestibuli in the region of the ductus reuniens, and, block it; and produce cochlear hydrops resulting in a delayed low tone loss of hearing in hybrid implants. Animal models cannot be applied to humans because of the difference in size and myelination of the neurons.

UV-Assisted 3D Bioprinting of Nanoreinforced Hybrid Cardiac Patch for Myocardial Tissue Engineering.

Biofabrication of cell supportive cardiac patches that can be directly implanted on myocardial infarct is a potential solution for myocardial infarction repair. Ideally, cardiac patches should be able to mimic myocardium extracellular matrix for rapid integration with the host tissue, raising the need to develop cardiac constructs with complex features. In particular, cardiac patches should be electrically conductive, mechanically robust and elastic, biologically active and prevascularized. In this study, we aim to biofabricate a nanoreinforced hybrid cardiac patch laden with human coronary artery endothelial cells (HCAECs) with improved electrical, mechanical, and biological behavior. A safe ultraviolet (UV) exposure time with insignificant effect on cell viability was identified for methacrylated collagen (MeCol) micropatterning. The effects of carboxyl functionalized carbon nanotubes (CNTs) on MeCol and alginate matrix morphology, mechanical properties, electrical behavior, and cellular response were investigated at different CNT mass ratios. A UV-integrated 3D-bioprinting technique was implemented to create hybrid hydrogel constructs consisting of CNT-incorporated alginate framework and cell-laden MeCol. The compressive modulus, impedance, and swelling degree of hybrid constructs were assessed over 20 days of incubation in culture medium at 37°C for different CNT mass ratios. The HCAEC viability, proliferation, and differentiation in the context of the bioprinted hybrid constructs were assessed over 10 days in vitro. The functionalized CNTs provided a highly interconnected nanofibrous meshwork that significantly improved viscoelastic behavior and electrical conductivity of photo-cross-linked MeCol. Alginate-coated CNTs provided a nanofilamentous network with fiber size of ∼25-500 nm, improving not only electrical and mechanical properties but also HCAEC attachment and elongation compared to pristine alginate. The CNT-reinforced 3D-printed hybrid constructs presented significantly higher stiffness and electrical conductivity particularly in the physiologically relevant frequency range (∼5 Hz). The CNT-reinforced hybrid implants maintained a significantly higher swelling degree over 20 days of culturing compared to CNT-free hybrid constructs. For a selected CNT mass ratio, HCAECs presented significant cellular proliferation, migration, and differentiation (lumen-like formation) over 10 days of incubation in vitro. Findings from this study deliver essential steps toward developing conductive, robust, and potentially prevascularized hybrid cardiac patches.

Value Driven Gynecologic Brachytherapy Through Appropriate Procedure Selection Optimizes Resources and Efficiency

Increasingly, healthcare organizations have begun focusing on the value and efficiency of delivered care given provider and resource limitations. For patients with locally advanced cervical cancer brachytherapy (BT) is part of the definitive treatment paradigm. We examined our institutional efficiency trends over 7 years to ascertain whether changes in BT technique affect clinical workflow, peri-procedural resource utilization, and the theoretical ability and impact for patient-specific conversion from interstitial to hybrid implantation for improved resource utilization. We reviewed cervical cancer pts treated consecutively and definitively at our institution using either hybrid or interstitial techniques from 2011 – 2017. We collected process efficiency data related to physician, dosimetry, and physics planning time, patient demographics, and peri-procedural: antibiotic, narcotic, sedative, anti-emetic, and intravenous fluid (IVF) utilization. The potential to convert an interstitial to hybrid implant was determined by expert review. Statistical analyses were performed using two-tailed t-test with significance set at p < 0.05. From 2011 – 2017, 14 hybrid and 25 interstitial cervical cancer patients were treated definitively with external beam radiation and BT. Comparison of median time for hybrid and interstitial physician planning (28 vs 59 min), dosimetry (47 vs 63 min), and physics review (13 vs 23 min) was significant for all metrics, p < 0.01. 7 of 25 (28%) patients potentially could have been converted from interstitial to hybrid implantation. All interstitial patients had epidural anesthesia, were hospitalized for BT implant, and 11/14 had dilaudid PCA. For hybrid vs interstitial patients, p < 0.05 for: average peri-procedural cephazolin (1.5 vs 5.9 g), fentanyl (370 vs 174 ug), dilaudid (2.18 vs 21.8 mg), post-implant morphine equivalent dose (MED; 8.3 vs 132 mg), midazolam (8.2 vs 3.7 mg), ondansetron (4.4 vs 6.7 mg), diphenhydramine (48 vs 35 mg), and IVF (1.2 vs 1.6 L). Resources can be used more efficiently in the definitive treatment of locally advanced cervical cancer through the appropriate selection of specific gynecologic brachytherapy techniques. 7 of 25 interstitial patients (28%) theoretically could have received hybrid BT implants and avoided hospitalization, thus improving resource utilization. Our study also shows a drastic 40% reduction in total procedural treatment time (p < 0.01) for hybrid implants compared with interstitial implants. Finally, use of hybrid BT techniques significantly reduces peri-procedural medication requirements and thus the risk for iatrogenic harm. Taken together, hybrid BT has the potential to greatly optimize healthcare resource utilization and clinical efficiency, and reduce the risk of iatrogenic harm.

A stepwise under-prepared osteotomy technique improves primary stability in shallow-placed implants: a preliminary study for simultaneous vertical ridge augmentation.

Simultaneous vertical ridge augmentation (VRA) can reduce treatment procedures and surgery time, but the concomitant reduction in primary stability (PS) of a shallow-placed implant imparts risk to its prognosis. Although several studies have reported improvements in PS, there is little information from any simultaneous VRA model. This study aimed to evaluate whether tapered implants with stepwise under-prepared osteotomy could improve the PS of shallow-placed implants in an in vitro model of simultaneous VRA. Tapered implants (Straumann® Bone Level Tapered implant; BLT) and hybrid implants (Straumann® Bone Level implant; BL) were investigated in this study. A total of 80 osteotomies of different depths (4, 6, 8, 10mm) were created in rigid polyurethane foam blocks, and each BLT and BL was inserted by either standard (BLT-S, BL-S) or a stepwise under-prepared (BLT-U, BL-U) osteotomy protocol. The PS was evaluated by measuring maximum insertion torque (IT), implant stability quotient (ISQ), and removal torque (RT). The significance level was set at P<0.05. There were no significant differences in IT, ISQ or RT when comparing BLT-S and BL-S or BLT-U and BL-U at placement depths of 6 and 8mm. When comparison was made between osteotomy protocols, IT was significantly greater in BLT-U than in BLT-S at all placement depths. A stepwise under-prepared osteotomy protocol improves initial stability of a tapered implant even in a shallow-placed implant model. BLT-U could be a useful protocol for simultaneous VRA.

Injectable chitosan-platelet-rich plasma implants to promote tissue regeneration: in vitro properties, in vivo residence, degradation, cell recruitment and vascularization.

The purpose of this study was to develop freeze-dried chitosan formulations that can be solubilized in platelet-rich plasma (PRP) to form injectable implants for tissue repair. A systematic approach to adjust formulation parameters, including chitosan number average molar mass (Mn ), chitosan concentration and lyoprotectant concentration, was undertaken to identify compositions that would rapidly (< 1min) and completely solubilize in PRP, would have paste-like handling properties upon solubilization and coagulate rapidly (< 5min) to form solid chitosan-PRP hybrid implants that are stable and homogenous. Freeze-dried cakes containing calcium chloride, as well as distinct chitosan Mn , chitosan concentration and lyoprotectant concentration, were prepared. PRP was used to solubilize the freeze-dried cakes and assess in vitro and in vivo performance, the latter as dorsal subcutaneous injections into New Zealand White rabbits. Freeze-dried polymer formulations containing low and medium chitosan Mn and concentrations were rapidly and completely solubilized in PRP. The paste-like chitosan-PRP mixtures coagulated quickly to form solid chitosan-PRP hybrids, which retracted much less than PRP-only controls. Homogeneous dispersion of chitosan within the hybrid clots was strongly dependent on chitosan Mn , and occurred only with medium Mn chitosan. Chitosan-PRP hybrid clots were resident subcutaneously in vivo until at least 2weeks while PRP controls were quickly degraded in one day. Compared to PRP alone, chitosan-PRP hybrids had much greater capacity to induce local cell recruitment accompanied by angiogenesis, suggesting a strong potential for their use in regenerative medicine. Copyright © 2017 John Wiley & Sons, Ltd.

Hybrid Implants in Healthy and Periodontally Compromised Patients: A Preliminary Clinical and Radiographic Study.

This preliminary clinical and radiographic study examined the survival of, the marginal bone loss (MBL) around, and the influence of prosthetic abutment height (AH) on MBL around hybrid implants placed in two groups of partially edentulous patients: healthy (HPs) and periodontally compromised (PCPs) patients. A total of 93 patients requiring single or multiunit implant restoration, in the mandible or maxilla, were treated while undergoing cement-retained prosthetic restoration. A total of 54 implants (35 in the maxilla and 19 in the mandible) were placed in 45 HPs, and 56 implants (31 in the maxilla and 25 in the mandible) in 48 PCPs. All 110 hybrid implants positioned in pristine bone provided a 100% survival rate in both HPs and PCPs. No statistical differences were recorded comparing the MBL values of maxillae with those of mandibles. In HPs and PCPs, a similar and limited amount of MBL was recorded, and it was found that the higher the AH, the less MBL. In conclusion, results indicate that the hybrid implants examined could reduce the risk of peri-implantitis due to their coronal machined surfaces and improve osseointegration due to their apical rough surfaces.

Total hip replacement: A meta-analysis to evaluate survival of cemented, cementless and hybrid implants.

AIMTo determine whether cemented, cementless, or hybrid implant was superior to the other in terms of survival rate.METHODSSystematic searches across MEDLINE, CINAHL, and Cochrane that compared cemented, cementless and hybrid total hip replacement (THR) were performed. Two independent reviewers evaluated the risk ratios of revision due to any cause, aseptic loosening, infection, and dislocation rate of each implants with a pre-determined form. The risk ratios were pooled separately for clinical trials, cohorts and registers before pooled altogether using fixed-effect model. Meta-regressions were performed to identify the source of heterogeneity. Funnel plots were analyzed.RESULTSTwenty-seven studies comprising 5 clinical trials, 9 cohorts, and 13 registers fulfilled the research criteria and analyzed. Compared to cementless THR, cemented THR have pooled RR of 0.47 (95%CI: 0.45-0.48), 0.9 (0.84-0.95), 1.29 (1.06-1.57) and 0.69 (0.6-0.79) for revision due to any reason, revision due to aseptic loosening, revision due to infection, and dislocation respectively. Compared to hybrid THR, the pooled RRs of cemented THR were 0.82 (0.76-0.89), 2.65 (1.14-6.17), 0.98 (0.7-1.38), and 0.67 (0.57-0.79) respectively. Compared to hybrid THR, cementless THR had RRs of 0.7 (0.65-0.75), 0.85 (0.49-1.5), 1.47 (0.93-2.34) and 1.13 (0.98-1.3).CONCLUSIONDespite the limitations in this study, there was some tendency that cemented fixation was still superior than other types of fixation in terms of implant survival.

Orbital fracture repair outcomes with preformed titanium mesh implants and comparison to porous polyethylene coated titanium sheets

BackgroundRestoration of orbital volume after internal orbital fractures can prevent enophthalmos. A variety of allografts are commonly used including titanium mesh with and without porous polyethylene coating. Some controversy exists over the use of uncoated titanium mesh in the orbit. Newer products contoured to the three dimensional orbital anatomy aim to improve reestablishment of the complex orbital shape though studies of outcomes with their use are limited. MethodsA retrospective chart review was performed to evaluate surgical outcomes in all patients who underwent orbital fracture repair with DePuy/Synthes titanium MatrixMIDFACE prefabricated implants (PFTi) as compared with porous polyethylene/titanium hybrid implants (PPETi) including Stryker Medpor Titan, MTB, and BTB implants. Incidence of reoperation, diplopia, and movement restriction between PFTi and PPETi groups and the risk ratio of the above outcomes between implant types were compared. ResultsA total of 464 orbital implants were reviewed. Patients were divided by implant type with 195 patients receiving a PFTi implant and 269 patients receiving PPETi implant. (PFTi) and 269 had placement of a porous polyethylene/titanium hybrid implant. Despite statistically significant increased probability of utilization in more complex and delayed fractures, the PFTi implant showed no significant difference in complication profile or reoperation rate compared to the more commonly used PPETi. ConclusionsPFTi implants, designed to replicate the native orbital shape, have similar surgical outcomes and no difference in complication profile compared to standard porous polyethylene/titanium implants hybrid plates.

Comparison of 2 Different Formulations of Artificial Bone for a Hybrid Implant With a Tissue-Engineered Construct Derived From Synovial Mesenchymal Stem Cells: A Study Using a Rabbit Osteochondral Defect Model

Background: Previously, we developed a hybrid implant composed of hydroxyapatite (HA)–based artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-engineered construct (TEC) and demonstrated its feasibility for osteochondral repair. Beta-tricalcium phosphate (βTCP) may be a promising alternative to HA, as it is a highly biocompatible material and is resorbed more rapidly than HA in vivo. Hypothesis: A βTCP-based hybrid TEC implant will exhibit superior osteochondral repair when directly compared with an HA-based hybrid implant, as tested using a rabbit osteochondral defect model. Study Design: Controlled laboratory study. Methods: Osteochondral defects were created in the femoral groove of skeletally mature rabbits. The TEC and artificial bone, using either HA or βTCP with the same porosities and similar mechanical properties, were hybridized and then implanted in the defects. A histological evaluation and microindentation testing were performed for the assessment of repair tissue. Results: Osteochondral defects treated with the TEC/βTCP implants showed more rapid subchondral bone repair at 1 month, but the cartilaginous tissue deteriorated over time out to 6 months after implantation. Osteochondral defects treated with the TEC/HA implants maintained good histological quality out to 6 months after implantation and also exhibited better biomechanical properties at 6 months as compared with the TEC/βTCP implants. Conclusion: Contrary to our hypothesis, the TEC/HA hybrid implant facilitated better osteochondral repair than did the TEC/βTCP implant. The results of the present study suggest the importance of a stable restoration of subchondral bone for long-term effective osteochondral repair rather than rapid remodeling of subchondral bone. Clinical Relevance: This study contributes to the future selection of suitable materials for patients with osteochondral lesions.

Performance differences between electroacoustic and electric alone cochlear stimulation using complex tests in noise. A pilot study

Objectives: Hybrid cochlear implants enable very interesting performances in bisyllabic words recognition, mainly in noisy conditions. In this paper, we studied patients with implants performing some very difficult timbric tasks in quiet and noisy conditions.Methods: We studied three adult patients with hybrid implants (group A-hybrid implants) and three adult patients with traditional ones (group B-traditional implants). We made the following tests (in quiet and noise): bisyllabic words recognition; voice kind recognition; common melodies identification and recognition; musical instrument identification and recognition.Results: Mean results in quiet: test 1: 35% A, 47% B; test 2: 92% A, 42% B; test 3: identification scores 88% A, 100% B, recognition scores: 37.5% A, 50% B; test 4 identification scores 50% A, 20% B, recognition scores 30% A, 20% B. As for tests in noise: test 1: 28% A, 46% B; test 2: 75% A, 25% B; test 3: identification 81% A, 87.5% B and recognition 56% A, 50% B; test 4: identification 60% A, 30% B and recognition 50% A, 20% B.Conclusion: Patients with hybrid implants seem to have better results, mainly in noisy timbric tasks. This could be explained by the better quality of low frequency stimulation and could be an encouragement for further studies and a larger diffusion of this kind of implant in the future.

Effect of Using Locator Versus O-Ring Attachments on Hybrid Implants Retaining Lower Complete Dentures

Effect of Using Locator Versus O-Ring Attachments on Hybrid Implants Retaining Lower Complete Dentures

Development of a novel hybrid strategy for transcatheter pulmonary valve placement in patients following transannular patch repair of tetralogy of fallot

Transcatheter pulmonary valve replacement (tPVR) is an accepted therapy for treatment of dysfunctional right ventricular outflow tract (RVOT) conduits. At present, the majority of Fallot patients who undergo transannular patch (TAP) repair are not candidates for tPVR due to the large irregular nature of their RVOT. Herein, we describe a novel approach to assessing the RVOT in this group, which may then be used to design, test, and carry out hybrid RVOT modification and transcatheter valve implantation in this population. A retrospective analysis of TAP patients who underwent 3D modeling of the RVOT which was then used to develop individualized hybrid procedures designed to modify the RVOT, thereby rendering patients suitable for transcatheter valve implantation. Eight consecutive patients underwent 3D RVOT modeling followed by hybrid implantation of a transcatheter valve via a perventricular approach. A landing zone stent was placed in all and four required additional intravascular geometric remodeling of the RVOT prior to valve implant. Transcatheter valves were successfully implanted in all. There were no instances of valve malposition, embolization, or death. There was one minor procedural complication. No patient had more than trivial pulmonary regurgitation at follow-up. Using a hybrid approach to remodel the RVOT in TAP patients supported by preprocedural 3D-model planning allows for successful tPVR implantation in this population. A larger cohort and longer follow-up will be needed to determine the ultimate utility of this approach.

Influence of Different Surface Characteristics on Peri-implant Tissue Behavior: A Six-Year Prospective Report

The aim of this study was to evaluate the behavior of hard and soft tissue around implants with different surface treatments. Eight patients were identified for this study. Each patient received at least 2 implants (1 control, 1 test) into an edentulous quadrant, for a total of 10 pairs of implants. Two types of implants were used: hybrid implants (control) with a dual acid-etched surface in their apical portion and a machined coronal part, and test implants with an acid-etched surface throughout their entire length. Standardized periapical radiographs were taken at baseline, 3 months, 6 months, and 1 year post implant placement and then annually until the 6-year follow-up. Bleeding on probing (BOP) and Plaque Index (PI) were recorded annually. Probing depth (PD) was recorded at the 6-year follow-up. Moderate crestal bone remodeling was observed during the 1-year postimplant placement evaluation (P=.001), and test implants revealed smaller marginal bone resorption (P=.030). No significant changes in bone level were observed between the 1-year and the 6-year follow-up appointments, and a significantly smaller bone resorption was found at test implants. No statistically significant differences in bone resorption were found between maxilla and mandible. No statistically significant differences were detected between test and control implants for BOP, PI, or PD. The preliminary results suggest that implant surface characteristics might affect the bone remodeling phase subsequent to the surgical trauma. However, once osseointegration was established, implant surfaces did not affect bone maintenance over time. Implant surfaces did not affect soft tissue behavior. The results of this pilot study need to be confirmed in a study with a larger sample size and over a longer time frame.

Fabrication of biomimetic polysiloxane-bioactive glass–chitosan hybrid monoliths with high apatite-forming bioactivity

The development of biomimetic hybrid implants with high bioactivity is very important for successful bone tissue regeneration. This paper presents a simple strategy for fabricating polydimethylsiloxane–bioactive glass–chitosan hybrid monoliths by a facile sol–gel process. Here, chitosan, which is a critical component in human body, is a natural biocompatible polymer and glycosaminoglycans. Our results indicate that the as-fabricated hybrid monoliths have a porous structure and crack-free morphology, and the in vitro bioactivity test demonstrates that the novel hybrid monoliths have a high apatite-forming ability in simulated body fluid. The facile synthesis, biomimetic structure and composition, as well as high bioactivity of the as-fabricated hybrid monoliths make them promising materials for applications in bone tissue regeneration.

The prognosis of total hip replacement in patients younger than 55 years of age. Results of 28,480 primary replacements from the Nordic Arthroplasty Register Association

Introduction The aim of this study was to evaluate the patient and surgery related risk factors for revision following primary THR in patients younger than 55 years of age using the large population-based NARA dataset. Materials and methods Through the Nordic Arthroplasty Register Association (NARA) dataset we identified all primary THRs due to osteoarthritis in patients younger than 55 years of age performed in four Nordic countries from 1995–2011 ( n = 28,480). We estimated overall risk for revision due to any reason, due to aseptic loosening, and risk for any revision within 2 years. We used Cox regression analyses to calculated crude and adjusted Hazard ratio as a relative risk (RR) and 95% confidence interval (CI) in order to study patient and surgery related risk factors for revision. Results Overall revision risk following primary THR due to any cause was 7.9% (2240 out of 28,480 primary THR), whereas the revision risk due to aseptic loosening was 4.2% (1192 out of 28,480 primary THR). No difference in any revision risk regarding sex and age was evident, but female had lower risk of revision due to aseptic loosening (RR = 0.86, 95% CI: 0.76–0.76). Uncemented implant had reduced risk for overall revision due to aseptic loosening (RR = 0.52, 95% CI: 0.45–0.59), whereas hybrid implants had higher risk for overall any revision compared with cemented technique (RR = 1.28, 95% CI: 1.13–1.45). However, overall differences were only observed during the period 1997-2003. Sex and age subgroup analyses reviled, that uncemented implants also had higher risk of any revision among females older than 45 years, whereas hybrid implants had particularly high risk for any revision among males older than 45 years. Conclusion Our large population-based study provides evidence that age, sex and calendar year of surgery were not risk factors for either overall any revision or revision due to aseptic loosening. In general, hybrid implant had higher risk for any revision, whereas uncemented implant had lower risk of revision due to aseptic loosening. However, the risk estimates for fixation technique were dependent on calendar year of surgery, as well as on age and gender.

Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

Background and purpose — The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods — We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results — In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation — In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients.

Association between fixation technique and revision risk in total hip arthroplasty patients younger than 55 years of age. Results from the Nordic Arthroplasty Register Association

To evaluate implant survival following primary total hip replacement (THR) in younger patients. To describe the diversity in use of cup-stem implant combinations. 29,558 primary THRs osteoarthritis (OA) patients younger than 55 years of age performed from 1995 through 2011 were identified using the Nordic Arthroplasty Registry Association database. We estimated adjusted relative risk (aRR) of revision with 95% confidence interval (CI) using Cox regression. In general, no difference was observed between uncemented and cemented implants in terms of risk of any revision. Hybrid implants were associated with higher risk of any revision (aRR = 1.3, CI: 1.1-1.5). Uncemented implants led to a reduced risk of revision due to aseptic loosening (aRR = 0.5, CI: 0.5-0.6), whereas the risk was similar for hybrid and cemented implants. Compared with cemented implants, both uncemented and hybrid implants led to elevated risk of revision due to other causes, as well as elevated risk of revision due to any reason within 2 years. 183 different uncemented cup-stem implant combinations were registered in Denmark, of these, 172 were used in less than 100 operations which is similar to Norway, Sweden and Finland. Uncemented implants perform better in relation to long-term risk of aseptic loosening, whereas both uncemented and hybrid rather than cemented implants in patients younger than 55 years had more short-term revisions because problems due to dislocation, periprosthetic fracture and infection has not yet been completely solved. The vast majority of cup-stem combinations were used in very few operations.

Primary Stability of a Hybrid Implant Compared with Tapered and Cylindrical Implants in an Ex Vivo Model

Hybrid implants are thought to offer good stability and bone-implant contact. This study sought to evaluate the primary stability of a hybrid implant compared with tapered and cylindrical implants in an ex vivo model and compare undersized drilling with standard drilling in attaining primary stability. Hybrid (Straumann® Bone Level; BL), tapered (Straumann® Tapered Effect; TE), and cylindrical (Straumann® Standard Plus; SP) implants were inserted into 15 mm-thick porcine iliac crest blocks using standard (corticocancellous or cancellous bone) or undersized (cancellous bone only) drilling (n = 7). Stability was evaluated using maximum insertion torque (MIT), implant stability quotient (ISQ), and push-out tests. The mean MIT for BL and TE was significantly higher than that for SP (p < 0.05). With standard drilling in corticocancellous bone, the mean ISQ for TE was significantly higher than that for SP (p < .05). The mean MIT, ISQ, and push-out test scores for BL, TE, and SP with standard drilling in corticocancellous bone were significantly higher than those with undersized or standard drilling in cancellous bone (p < .05). In this ex vivo model, the hybrid implant demonstrated promising primary stability compared with the cylindrical implant. The improved stability of the hybrid implant was especially evident in cancellous bone. The influence of the cortical layer should be recognized when selecting implants for primary stability.