Aseptic Osteolysis Research Articles

Role of miR-21-5p in the protective effects of PLGA-encapsulated extracellular vesicles from urine-derived stem cells on periprosthetic osteolysis

Periprosthetic osteolysis (PPOL), a form of aseptic osteolysis, accounts for most total hip arthroplasty (THA) revisions, necessitating the development of effective therapeutic strategies. We aimed to investigate the anti-inflammatory effects of poly(lactic-co-glycolic acid) (PLGA) nanoparticles-encapsulated extracellular vesicles (EVs) obtained from human urine-derived stem cells (USC-EVs) on osteolysis and elucidate the underlying mechanism. PLGA nanoparticles-encapsulated USC-EVs (PLGA-EVs) were synthesized by mechanical double-emulsion method. We locally injected PLGA-EVs into a mouse calvarial osteolysis model and evaluated their efficacy using micro-computed tomography and histological analyses. We assessed the osteoclastogenesis of RAW264.7 cells co-cultured with USC-EVs and determined the expression levels of inflammatory genes using qRT-PCR. Based on the microarray data and qRT-PCR results, we focused on microRNA-21–5p (miR-21–5p), a known regulator of the inflammatory response. We used specific miRNA antagomirs to examine miR-21–5p's role in the USC-EV-mediated inflammation regulation and osteolysis inhibition. Additionally, miR-21–5p's effect on PTEN was also analyzed. USC-EVs were efficiently endocytosed by RAW264.7 cells in vitro, decreasing osteoclastogenesis and reducing the expression of inflammatory genes. Locally injected USC-EVs persisted for ∼2 weeks and significantly mitigated osteolysis in vivo. Moreover, PLGA-EVs cloud be internalized by RAW264.7 cells in vitro and locally sustain a higher concentration in vivo. MiR-21–5p was highly enriched in USC-EVs and mediated the anti-inflammatory effects of USC-EVs by inhibiting PTEN. PLGA-encapsulated USC-EVs alleviated aseptic osteolysis partly through miR-21–5p-mediated anti-inflammatory actions, highlighting their potential as therapeutic agents for PPOL.

Apelin-13 alleviates osteoclast formation and osteolysis through Nrf2-pyroptosis pathway.

Wear particle-induced periprosthetic osteolysis is the key to aseptic loosening after artificial joint replacement. Osteoclastogenesis plays a central role in this process. Apelin-13 is a member of the adipokine family with anti-inflammatory effects. Here, we report that apelin-13 alleviates RANKL-mediated osteoclast differentiation and titanium particle-induced osteolysis in mouse calvaria. Mechanistically, apelin-13 inhibits NLRP3 inflammasome-mediated pyroptosis by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In summary, apelin-13 is expected to be a potential drug for relieving aseptic osteolysis. RESEARCH HIGHLIGHTS: This study reveals the molecular mechanism by which apelin-13 inhibits NLRP3 inflammasome activation and pyroptosis by promoting Nrf2. This study confirms that apelin-13 alleviates osteoclast activation by inhibiting pyroptosis. In vivo studies further confirmed that apelin-13 alleviated mouse skull osteolysis by inhibiting the activation of NLRP3 inflammasome.

Mechanism of regulating macrophages/osteoclasts in attenuating wear particle-induced aseptic osteolysis.

Joint replacement surgery is the most effective treatment for end-stage arthritis. Aseptic loosening caused by periprosthetic osteolysis is a common complication after joint replacement. Inflammation induced by wear particles derived from prosthetic biomaterials is a major cause of osteolysis. We emphasize that bone marrow-derived macrophages and their fusion-derived osteoclasts play a key role in this pathological process. Researchers have developed multiple intervention approaches to regulate macrophage/osteoclast activation. Aiming at wear particle-induced periprosthetic aseptic osteolysis, this review separately discusses the molecular mechanism of regulation of ROS formation and inflammatory response through intervention of macrophage/osteoclast RANKL-MAPKs-NF-κB pathway. These molecular mechanisms regulate osteoclast activation in different ways, but they are not isolated from each other. There is also a lot of crosstalk among the different mechanisms. In addition, other bone and joint diseases related to osteoclast activation are also briefly introduced. Therefore, we discuss these new findings in the context of existing work with a view to developing new strategies for wear particle-associated osteolysis based on the regulation of macrophages/osteoclasts.

Bimetallic Metal–Organic Framework for Mitigating Aseptic Osteolysis

The disability rate of joint diseases can be reduced by the use of artificial joints, but joint loosening at a late state limits the lifespan and surgical efficacy of the joints. Wear particles can be recognized by macrophages and induce cells to produce reactive oxygen species (ROS) and inflammatory factors, causing persistent inflammation and decreased osteogenic activity, which ultimately leads to loosening of joint prostheses. Here, the platinum (Pt) nanozymes with excellent ROS scavenging and anti-inflammatory capabilities were encapsulated in zinc imidazolium zeolite framework-8 (ZIF-8), and then the osteogenic active element lanthanum (La) was introduced through ion exchange to finally construct a bimetallic metal-organic framework (Pt@ZIF-8@La). In vitro and in vivo experiments demonstrated that this multifunctional nanoplatform possessed the functions of efficient scavenging of ROS, immune regulation, and promotion of osteogenic differentiation. Meanwhile, the mechanism is explored that Pt@ZIF-8@La can also promote osteogenic mineralization by upregulating the ratio of the osteoprotegerin (OPG)/receptor activator of the NF-κB ligand (RANKL), which can achieve a synergistic therapeutic effect of immunomodulation and osteogenesis, thereby realizing the purpose of relieving aseptic osteolysis.

The Impact of Cement Mantle Characteristics on Early Loosening in Primary Total Elbow Arthroplasty

To assess the association between cement mantle characteristics and early radiographic loosening in total elbow arthroplasty (TEA). We aimed to determine whether shorter mantle heights (<20 mm) were associated with loosening. We reviewed primary TEAs from a single healthcare system from 2006 to 2020. TEAs complicated by infection or performed for oncologic conditions were excluded. Initial postoperative radiographs were reviewed to determine cement mantle and component characteristics (mantle quality, mantle height, and component angulation). One-year postoperative radiographs were reviewed to assess for implant loosening, and we compared demographics and radiographic criteria for cases with and without early loosening. We noted whether cases underwent subsequent revision for aseptic osteolysis. A total of 54 TEA cases were included. Forty percent of ulnar and 24% of humeral mantles were classified as short (between 1 and 19 mm). According to the Morrey classification, 6 (11%) cases had an inadequate cement mantle Twenty-four (45%) cases had radiographic evidence of loosening at 1 year. Of the cases with early loosening, 6 (25%) had initial inadequate mantle quality. There were no inadequate mantles in the group without loosening. There were no statistically significant differences in mantle heights for cases with and without loosening at 1 year after surgery. Eight (33%) cases underwent revision in the group with early loosening compared with 1 (3%) case without early loosening. Inadequate cement mantle quality was associated with an increased risk of early aseptic loosening after primary TEA. Cement mantles that extended past the tip of the prosthesis were not associated with loosening. Considering the potential need for future revision and morbidity of cement removal, surgeons should focus on mantle quality and carefully plan mantle height because shorter heights may not be associated with early implant failure. Prognostic II.

Midterm Survival of a Varus-Valgus Constrained Implant following One-Stage Revision for Periprosthetic Joint Infection: A Single-Center Study.

Revision total knee arthroplasty (TKA) is challenging to perform in patients with periprosthetic joint infection (PJI) due to the difficulty of eradicating the infection and potential for bone and ligamentous deficits. The current study aimed to evaluate the midterm survival of varus-valgus constrained (VVC) implants used in one-stage revision TKA for chronic PJI at our institution. This retrospective analysis included 132 patients with chronic PJI who underwent one-stage revision using a VVC implant. The average follow-up was 51.6 months (range: 24-85 months). Five-year survival analysis was performed to set recurrent infection and mechanical failure as the end point. Hospital for special surgery (HSS) as functional outcomes was evaluated preoperatively and at the latest follow-up. A total of 12 patients (9.1%) underwent retreatment for reinfection (nine patients) and mechanical failure (three patients). The overall 5-year revision-free survival was 82.7%, the infection-free survival was 91.1%, and the mechanical failure-free survival was 98.3%. The preoperative HSS knee score improved from 35.6 points (range: 24.3-47.7 points) preoperatively to 76.8 points (range: 57.2-87.6 points) at the latest follow-up. Complications were identified in 20 patients (15.2%) which included aseptic osteolysis in 4 cases, acceptable flexion instability in 3 cases, arthrofibrosis in 2 patients, hematomas in 2 cases, calf intermuscular venous thrombosis in 6 patients, and femoral stem tip pain in 3 cases. This is the first study to report the outcomes of one-stage revision using VVC implants for knee PJI. Improved functional outcomes and good midterm survival are demonstrated at an average follow-up of 51.6 months.

Outcome and Risk Factors Associated with Failures of Isolated Bearing Exchange for Osteolysis in Well-Fixed Cementless Total Hip Arthroplasty

BackgroundIt is often challenging to decide whether to revise only the bearing or femoral acetabular component in the setting of progressive osteolysis without component loosening in revision total hip arthroplasty (THA). In this study, we aimed to (1) compare the survivorship of isolated bearing exchange and single/both component revision for patients with periprosthetic osteolysis without component loosening, and (2) identify potential risk factors associated with failures of isolated bearing exchange. MethodsA total of 228 consecutive cases of revision THA for progressive osteolysis without component loosening was evaluated in 2 groups: (1) 124 component revision and (2) 104 isolated bearing exchange. The primary outcome was survival, with failure defined as repeat revision or reoperation for any reason. Patient risk factors, such as demographics and medical comorbidities, were also analyzed. ResultsThere was no significant difference in survivorship between the component revision group and the bearing exchange group at 10 years (85% vs 82%; P = .89). There was no progression of osteolysis on radiographs at last follow-up for patients with isolated bearing change. Univariate regression modeling demonstrated that renal disease was associated with failure of isolated bearing exchange after revision THA. ConclusionThis study demonstrated that isolated bearing exchange is associated with similar outcomes compared with component revision for aseptic osteolysis without loosening, demonstrating that isolated bearing exchange is a viable option for selected patients with osteolysis in the setting of well-fixed THA components. This provides clinically useful information for surgeons in the surgical treatment of THA patients with wear and osteolysis without component loosening.

DAPT inhibits titanium particle-induced osteolysis by suppressing the RANKL/Notch2 signaling pathway.

Artificial prosthesis is wildly used in clinical medicine for degenerative disease such as osteoclast-related diseases. However, the material wear particles released from the surface of prostheses cause prosthetic loosening as a result of aseptic osteolysis in long-term use. Therefore, it is important to find an agent that inhibits the formation and function of osteoclast for therapeutic use. Notch signaling pathway plays a lot of roles in cell proliferation, differentiation, and apoptosis. However, the role of Notch signaling pathway in osteoclastogenesis remains unclear. The aim of this study is to assess the effects of γ-secretase inhibitor DAPT on osteoclastogenesis via Notch signaling pathway in vitro and titanium particle-induced osteolysis in vivo. In animal experiments, the inhibitory effect of DAPT on titanium particle-induced osteolysis in a mouse calvaria model was demonstrated. Interestingly, few resorption pits were observed following administration of DAPT and almost no osteoclasts formed at high concentration of DAPT. in vitro experiments revealed the mechanism of the effects of DAPT on osteoclastogenesis. DAPT inhibited the formation and function of osteoclast by blocking RANKL-induced Notch2-NF-κB complex signaling pathway. In conclusion, these results indicated that DAPT could prevent and cure titanium particle-induced prosthetic loosening and other osteoclast-related diseases.

Targeting autophagy to inhibit wear debris-induced osteolysis

Arthroplasty surgery has become one of the most efficient procedures to restore joint function. However, implant failure due to bone loss is a major complication of joint replacement, with severe consequences both for the individual patient and for health-care systems. Peri-prosthetic loosening without concurrent infection or trauma is called aseptic loosening. It is estimated that up to 20% of all prosthetic implants will induce aseptic osteolysis, generally leading to implant loosening and surgical revision (1).

Assessing the Suitability of Cellulose-Nanodiamond Composite As a Multifunctional Biointerface Material for Bone Tissue Regeneration.

Interfacial surface properties, both physical and chemical, are known to play a critical role in achieving long-term stability of cell-biomaterial interactions. Novel bone tissue engineering technologies, which provide a suitable interface between cells and biomaterials and mitigate aseptic osteolysis, are sought and can be developed via the incorporation of nanostructured materials. In this sense, engineered nanobased constructs provide an effective interface and suitable topography for direct interaction with cells, promoting faster osseointegration and anchoring. Therefore, herein we have investigated the surface functionalization, biocompatibility, and effect of cellulose-nanodiamond conjugates on osteoblast proliferation and differentiation. Cellulose nanocrystals (CNC) were aminated through a 3-aminopropyltriethyoxysilane (APTES) silylation, while nanodiamonds (ND) were treated with a strong acid oxidation reflux, as to produce carboxyl groups on the surface. Thereafter, the two products were covalently joined through an amide linkage, using a common bioconjugation reaction. Human fetal osteoblastic cells (hFOB) were seeded for 7 days to investigate the in vitro performance of the cellulose-nanodiamond conjugates. By employing immunocytochemistry, the bone matrix expression of osteocalcin (OC) and bone sialoprotein (BSP) was analyzed, demonstrating the viability and capacity of osteoblasts to proliferate and differentiate on the developed composite. These results suggest that cellulose-nanodiamond composites, which we call oxidized biocompatible interfacial nanocomposites (oBINC), have the potential to serve as a biointerface material for cell adhesion, proliferationand differentiation because of their osteoconductive properties and biocompatibility; furthermore, they show promising applications for bone tissue regeneration.

Anatomical and Functional Preliminary Results of Total Non-Cemented Hip Prostheses

The aim of this work was to assess the preliminary anatomical and functional results of patients to establish prospects. Materials and method: We report here the preliminary results of a retrospective mono-centric, homogeneous and continuous series, of 21 non-cemented total hip implants, implanted from January 2011 to December 2014. The mean follow-up time was 24 months. The patients were evaluated by Harris’s hip at the last follow-up. Results: The mean age of the intervention was 30 years. In our series, we observed a male predominance (60% of cases). Clinically, the Harris score varied significantly from 52.6 ± 11.4 pre-operatively to 85.1 ± 5.1 during the last follow-up visit. Among the items in the score, pain was the parameter that showed the greatest improvement. Thigh pain was observed in only one patient operated on the two sides. At the level of radiology, the femoral implant showed great stability. Bone resorption was suspected in 14 cases (66.66%), and confirmed in 4 cases (19.04%) with excellent bone remodeling, illustrated by the Engh and Massin scores. A loosening and a prosthetic dislocation was observed in a patient (4.76%). Any heterotopic ossification was observed. Conclusion: Our study confirmed good clinical and radiological results of the non-cemented hip prosthesis series in young patients. The rates of aseptic loosening, acetabular edges or osteolysis are low and stable over time.

Influence of particulate and dissociated metal-on-metal hip endoprosthesis wear on mesenchymal stromal cells in vivo and in vitro

In hip arthroplasty the implants' articulating surfaces can be made of a cobalt-chromium-molybdenum (CoCrMo) alloy. The use of these metal-on-metal (MoM) pairings can lead to the release of wear products such as metallic particles and dissociated metal species, raising concerns regarding their safety amongst orthopedic surgeons and the public. MoM-wear particles are reported to be heterogeneous in their physicochemical properties, are capable of inducing adverse effects on a cellular level and are thought to be involved in relevant clinical problems like aseptic osteolysis. Yet, it remains elusive how MoM-wear affects bone forming cells and their progenitors: bone marrow residing mesenchymal stromal cells (MSCs). This study introduces an assessment of the in vivo exposure to particulate and dissociated Co and Cr and evaluates the effects of MoM-wear on MSCs. The exposure to MoM-wear products in vivo and in vitro leads to a decrease in MSCs' osteogenic matrix mineralization and alkaline phosphatase activity on a cellular and systemic level. In conclusion, MoM-wear products are released in the periprosthetic region and elevate bone marrow Co and Cr concentrations towards levels that impair osteogenic differentiation of MSCs. Therefore, the ongoing use of CoCrMo alloys for articulating surfaces in joint replacement implants needs critical reconsideration.

Biologic Responses to Orthopedic Implants: Innate and Adaptive Immune Responses to Implant Debris.

Almost 20% of joint replacement implants fail at 15 to 20 years. Reports suggest that systemic effects of metal-on-metal implants and local effects of total joint arthroplasty implants contributing to implant failure are immune system based. Sometimes implant wear debris can cause implant failure resulting from bone fracture, infection, or implant fracture/failure; most often, aseptic osteolysis or loosening leads to wear debris. Debris is produced by wear (primary) or by corrosion. Corrosion-chemical oxidation comprising reduction reactions involving electron transport-produces electrochemical degradation. Metallic implant degradation occurs when electrochemical dissolution and mechanical/physical wear are combined (i.e., tribocorrosion). With metal-on-metal implants, even with relatively low levels of wear and particle release, pathology caused by metal debris such as pseudotumor/fibrous tissue growth can lead to early implant failure.

Similar effect of stem geometry on radiological changes with 2 types of cemented straight stem

Background and purpose — There are 2 basic principles in cemented stem fixation: shape-closed and force-closed. We investigated 2 shape-closed straight stems, the Müller (MSS) and the Virtec (VSS), which differ only in geometrical cross section, to determine whether the difference in stem shape would affect the radiological results or long-term survival.Patients and methods — We included 711 hips (in 646 patients) that were operated on between July 1996 and July 2003. Patients randomly received either an MSS (n = 356) or a VSS (n = 355) and were followed prospectively. Radiographs taken at a follow-up of > 10 years were analyzed for osteolysis. Kaplan-Meier (KM) survival analysis was performed using various endpoints. We also performed Cox regression analysis to identify risk factors for aseptic loosening and osteolysis of the stem.Results — After 10 years, KM survival with “revision of any component for any reason” was 92% (95% CI: 88–95) for the MSS and 95% (CI: 92–97) for the VSS (p = 0.1). With “revision for aseptic loosening of the stem” as the endpoint, KM survival was 96% (CI: 9–98) for the MSS and 98% (CI: 97–100) for the VSS (p = 0.2). Cox regression showed that none of the risk factors analyzed were independent regarding aseptic loosening of the stem or regarding osteolysis.Interpretation — The MSS and the VSS showed excellent survival for aseptic loosening after 10 years. For the 2 different stem designs, we did not find any independent risk factors for aseptic loosening or development of osteolysis.

Microbiological Testing of Biodegradable MgCa Alloys for Use in Orthopedic Implants

Implants based on titanium alloys, stainless steel and cobalt –chromium have been the primary biomaterials used for load bearing applications and they have been remarkably successful throughout time, but on the long term, there appear a series of inconveniences regarding these metallic implants. Thus, there have been cases of aseptic osteolysis around the implant, with pain and high degree of loosening of the prosthesis which constitutes a limitation of the long term benefits of metallic implants. Therefore, researchers have found new materials for implants, more competitive and efficient. These are materials that are biocompatible and biodegradable. These constitute a novel class of bioactive biomaterials which are expected to support the healing process of a diseased tissue and to degrade thereafter. Magnesium alloys attracted great attention as a new kind of degradable biomaterial. Mg is an essential mineral for human metabolism and its deficiency has been linked to various pathological conditions. The main advantages of Mg alloys are its superior mechanical and biocorrosive properties and its biocompatibility. Mg is a very light-weight metal with a lower density than that of biocompatible Ti alloys, which is closer to that of the human bone. In the present paper we shall focus on presenting some biological testing studies of several Mg alloys from the system Mg-Ca, with different percentages of Ca. Three methods have been use for this: determining the ph at different sample incubation times in culture environment; citotoxicity tests made in vitro which: evaluate the contact toxicity by putting the samples in the buckets of cellular culture plates; evaluate the cellular proliferation at the surface of the tested materials by fluorescence microscopy and deflection microscopy; evaluation of toxicity by testing the effect of the extraction liquid resulting from the incubation of the material with testing cell specific culture environment.

Technical tips for the removal of TightRope ankle syndesmosis fixation.

The use of a pre-assembled suture-endobutton system (TightRope, Arthrex, Inc., Naples, FL) for fixation of distal tibiofibular syndesmotic disruption has become increasingly popular over the last years. It has been initially introduced as a device, which can remain in situ indefinitely [1]. However, local wound irritation and infection from a prominent suture knot, aseptic osteolysis, osteomyelitis and subsidence of the device have been reported, necessitating a mean implant removal in 7.5% of the cases (range 0–25%) after an average follow-up of 18 months (range 3–28 months) [2–9]. We therefore present technical tips to facilitate the removal of the primary TightRope suture-button device.

Innate immune reactions in septic and aseptic osteolysis around hip implants.

According to the long-standing definition, septic and aseptic total joint replacement loosening are two distinct conditions with little in common. Septic joint replacement loosening is driven by bacterial infection whereas aseptic loosening is caused by biomaterial wear debris released from the bearing surfaces. However, recently it has been recognized that the mechanisms that drive macrophage activation in septic and aseptic total joint replacement loosening resemble each other. In particular, accumulating evidence indicates that in addition to mediating bacterial recognition and the subsequent inflammatory reaction, toll-like receptors (TLRs) and their ligands, pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPS), play a key role in wear debris-induced inflammation and macrophage activation. In addition, subclinical bacterial biofilms have been identified from some cases of seemingly aseptic implant loosening. Furthermore, metal ions released from some total joint replacements can activate TLR signaling similar to bacterial derived PAMPs. Likewise, metal ions can function as haptens activating the adaptive immune system similar to bacterial derived antigens. Thus, it appears that aseptic and septic joint replacement loosening share similar underlying pathomechanisms and that this strict dichotomy to sterile aseptic and bacterial-caused septic implant loosening is somewhat questionable. Indeed, rather than being two, well-defined clinical entities, peri-implant osteolysis is, in fact, a spectrum of conditions in which the specific clinical picture is determined by complex interactions of multiple local and systemic factors.

Complications of total hip arthroplasty: periprosthetic fractures of the acetabulum.

Periprosthetic fractures of the acetabulum are a rare but potentially disastrous complication of total hip arthroplasty. Such fractures occur either as early perioperative complications or late complications when they are associated with either significant trauma or as a result of the loss of the structural integrity of the bone supporting the prosthesis, such as aseptic osteolysis. The incidence of such fractures appears to be increasing with the increased use of uncemented acetabular components. This article explores the current literature on the epidemiology, etiology, and classification of periprosthetic acetabular fractures as well as offering potential treatment strategies.

Management of Extensive Talar Osteolysis with Agility™ Total Ankle Replacement Systems Using Geometric Metal-reinforced Polymethylmethacrylate Cement Augmentation

The Agility™ Total Ankle Replacement System, almost exclusively without polymethylmethacrylate cement fixation, was the most commonly used implant in the United States from 1998 to 2007. Much attention has been given to the intraoperative complications and incision healing-related problems. However, it is the intermediate- and long-term complications, specifically, aseptic osteolysis, talar component loosening, subsidence, and progressive malalignment, that require careful consideration, because the revision options are limited. We describe a technique for management of extensive talar aseptic osteolysis for revision of Agility™ total ankle replacement systems with use of geometric metal-reinforced polymethylmethacrylate cement augmentation. This technique preserves the subtalar joint, provides immediate component stability and restoration of component alignment and height, and is a cost-effective alternative to other available options and still allows for additional revision should late failure occur.

Results of Wagner SL revision stem with impaction bone grafting in revision total hip arthroplasty

Background:As the number of total hip arthroplasties (THAs) performed increases, so do the number of required revisions. Impaction bone grafting with Wagner SL Revision stem is a good option for managing bone deficiencies arising from aseptic osteolysis. We studied the results of cementless diaphyseal fixation in femoral revision after total hip arthroplasty and whether there was spontaneous regeneration of bone stock in the proximal femur after the use of Wagner SL Revision stem (Zimmer, Warsaw, IN, USA) with impaction bone grafting.Materials and Methods:We performed 53 hip revisions using impaction bone grafting and Wagner SL Revision stems in 48 patients; (5 cases were bilateral) for variety of indications ranging from aseptic osteolysis to preiprosthetic fractures. The average age was 59 years (range 44-68 years). There were 42 male and 6 female patients. Four patients died after surgery for reasons unrelated to surgery. 44 patients were available for complete analysis.Results:The mean Harris Hip Score was 42 before surgery and improved to 86 by the final followup evaluation at a mean point of 5.5 years. Of the 44 patients, 87% (n=39) had excellent results and 10% (n=5) had good results. The stem survival rate was 98% (n=43).Conclusion:Short term results for revision THA with impaction bone grafting and Wagner SL revision stems are encouraging. However, it is necessary to obtain long term results through periodic followup evaluation, as rate of complications may increase in future.