Hydrogen-treated CoCrMo alloy: a novel approach to enhance biocompatibility and mitigate inflammation in orthopedic implants.

In recent decades, orthopedic implants have been widely used as materials to replace human bone tissue functions. Among these, metal implants play a crucial role. Metals with better chemical stability, such as stainless steel, titanium alloys, and cobalt-chromium-molybdenum (CoCrMo) alloy, are commonly used for long-term applications. However, good chemical stability can result in poor tissue integration between the tissue and the implant, leading to potential inflammation risks. This study creates hydrogenated CoCrMo (H-CoCrMo) surfaces, which have shown promise as anti-inflammatory orthopedic implants. Using the electrochemical cathodic hydrogen-charging method, the surface of the CoCrMo alloy was hydrogenated, resulting in improved biocompatibility, reduced free radicals, and an anti-inflammatory response. Hydrogen diffusion to a depth of approximately 106 ± 27 nm on the surface facilitated these effects. This hydrogen-rich surface demonstrated a reduction of 85.2% in free radicals, enhanced hydrophilicity as evidenced by a decrease in a contact angle from 83.5 ± 1.9° to 52.4 ± 2.2°, and an increase of 11.4% in hydroxyapatite deposition surface coverage. The cell study results revealed a suppression of osteosarcoma cell activity to 50.8 ± 2.9%. Finally, the in vivo test suggested the promotion of new bone formation and a reduced inflammatory response. These findings suggest that electrochemical hydrogen charging can effectively modify CoCrMo surfaces, offering a potential solution for improving orthopedic implant outcomes through anti-inflammatory mechanisms.

Poly(methyl methacrylate) in Orthopedics: Strategies, Challenges, and Prospects in Bone Tissue Engineering.

Poly(methyl methacrylate) (PMMA) is widely used in orthopedic applications, including bone cement in total joint replacement surgery, bone fillers, and bone substitutes due to its affordability, biocompatibility, and processability. However, the bone regeneration efficiency of PMMA is limited because of its lack of bioactivity, poor osseointegration, and non-degradability. The use of bone cement also has disadvantages such as methyl methacrylate (MMA) release and high exothermic temperature during the polymerization of PMMA, which can cause thermal necrosis. To address these problems, various strategies have been adopted, such as surface modification techniques and the incorporation of various bioactive agents and biopolymers into PMMA. In this review, the physicochemical properties and synthesis methods of PMMA are discussed, with a special focus on the utilization of various PMMA composites in bone tissue engineering. Additionally, the challenges involved in incorporating PMMA into regenerative medicine are discussed with suitable research findings with the intention of providing insightful advice to support its successful clinical applications.

Enhancing wound healing and adhesion through dopamine-assisted gelatin-silica hybrid dressings.

Gelatin, widely employed in hydrogel dressings, faces limitations when used in high fluid environments, hindering effective material adhesion to wound sites and subsequently reducing treatment efficacy. The rapid degradation of conventional hydrogels often results in breakdown before complete wound healing. Thus, there is a pressing need for the development of durable adhesive wound dressings. In this study, 3-glycidoxypropyltrimethoxysilane (GPTMS) was utilized as a coupling agent to create gelatin-silica hybrid (G-H) dressings through the sol-gel method. The coupling reaction established covalent bonds between gelatin and silica networks, enhancing structural stability. Dopamine (DP) was introduced to this hybrid (G-H-D) dressing to further boost adhesiveness. The efficacy of the dressings for wound management was assessed through in-vitro and in-vivo tests, along with ex-vivo bioadhesion testing on pig skin. Tensile bioadhesion tests demonstrated that the G-H-D material exhibited approximately 2.5 times greater adhesion to soft tissue in wet conditions compared to pure gelatin. Moreover, in-vitro and in-vivo wound healing experiments revealed a significant increase in wound healing rates. Consequently, this material shows promise as a viable option for use as a moist wound dressing.

Clinical outcomes of various types of revision surgeries after unicompartmental knee arthroplasty failure.

PURPOSE: The advantages of unicompartmental knee arthroplasty (UKA) have led to the procedure being increasingly performed worldwide. However, revision surgery is required after UKA failure. According to the literature review, the choice of implant in revision surgery remains a debatable concern. This study analyzed the clinical results of different types of prostheses used in treating failed UKA. MATERIALS AND METHODS: This is a retrospective review of 33 failed medial UKAs between 2006 and 2017. Demographic data, failure reason, types of revision prostheses, and the severity of bone defects were analyzed. The patients were classified into three groups: primary prosthesis, primary prosthesis with a tibial stem, and revision prosthesis. The implant survival rate and medical cost of the procedures were compared. RESULTS: A total of 17 primary prostheses, 7 primary prostheses with tibial stems, and 9 revision prostheses were used. After a mean follow-up of 30.8 months, the survival outcomes of the three groups were 88.2%, 100%, and 88.9%, respectively (P = 0.640). The common bone defect in tibia site is Anderson Orthopedic Research Institute [AORI] grade 1 and 2a (16 versus 17). In patients with tibial bone defects AORI grade 2a, the failure rates of primary prostheses and primary prostheses with tibial stems were 25% and 0%, respectively. CONCLUSIONS: The most common cause for UKA failure was aseptic loosening. The adoption of a standardized surgical technique makes it easier to perform revision surgeries. Primary prostheses with tibial stems provided higher stability, leading to a lower failure rate due to less risk of aseptic loosening in patients with tibial AORI grade 2a. In our experience, we advise surgeons may try using primary prostheses in patients with tibial AORI grade 1 and primary prostheses with tibial stems in patients with tibial AORI grade 2a.

Preparation of gamma poly-glutamic acid/hydroxyapatite/collagen composite as the 3D-printing scaffold for bone tissue engineering.

BACKGROUND: All types of movements involve the role of articular cartilage and bones. The presence of cartilage enables bones to move over one another smoothly. However, repetitive microtrauma and ischemia as well as genetic effects can cause an osteochondral lesion. Numerous treatment methods such as microfracture surgergy, autograft, and allograft, have been used, however, it possesses treatment challenges including prolonged recovery time after surgery and poses a financial burden on patients. Nowadays, various tissue engineering approaches have been developed to repair bone and osteochondral defects using biomaterial implants to induce the regeneration of stem cells.  METHODS: In this study, a collagen (Col)/γ-polyglutamate acid (PGA)/hydroxyapatite (HA) composite scaffold was fabricated using a 3D printing technique. A Col/γ-PGA/HA 2D membrane was also fabricated for comparison. The scaffolds (four layers) were designed with the size of 8 mm in diameter and 1.2 mm in thickness. The first layer was HA/γ-PGA and the second to fourth layers were Col/γ-PGA. In addition, a 2D membrane was constructed from hydroxyapatite/γ-PGA and collagen/γ-PGA with a ratio of 1:3. The biocompatibility property and degradation activity were investigated for both scaffold and membrane samples. Rat bone marrow mesenchymal stem cells (rBMSCs) and human adipose-derived stem cells (hADSCs) were cultured on the samples and were tested in-vitro to evaluate cell attachment, proliferation, and differentiation. In-vivo experiments were performed in the rat and nude mice models. RESULTS: In-vitro and in-vivo results show that the developed scaffold is of well biodegradation and biocompatible properties, and the Col-HA scaffold enhances the mechanical properties for osteochondrogenesis in both in-vitro and animal trials. CONCLUSIONS: The composite would be a great biomaterial application for bone and osteochondral regeneration.

Acetabular Revision Surgery with Tantalum Trabecular Metal Acetabular Cup for Failed Acetabular Cage Reconstruction with Bone Allografts: A Retrospective Study with Mid- to Long-Term Follow-Up.

Background: Acetabular cage reconstruction with bone allografts is among the successful strategies to deal with massive acetabular bone loss. However, the nonbiological fixation nature of cages can compromise long-term success. Tantalum trabecular metal acetabular cups (TM cups) have been used in acetabular revision surgery because of their increased initial stability and good bone ingrowth features. This study was performed to determine whether the bone stock of the acetabulum is enough to support a hemispheric TM cup after failed cage reconstruction with bone allografts. Methods: We retrospectively reviewed patients who received acetabular revision surgery with TM cups after failed cage reconstruction with bone allografts from 2006 to 2017. There were 12 patients (5 males and 7 females) included in this study, with a mean age of 61.5 years (38 to 81) at the time of re-revision surgery. The mean follow-up after re-revision surgery was 8.6 years (2.6 to 13.3). The endpoint was defined as the aseptic loosening of the TM cup and reoperation for any causes. The change in bone stock of the acetabulum between index revision and re-revision was assessed according to the Gross classification for acetabular bone loss. Results: One patient died after eight years of follow-up of a cause not related to hip surgery. Two patients received two-stage revision arthroplasty due to PJI after 3.2 and 9.4 years of follow-up, respectively. The bone stock of the acetabulum was significantly improved between index revision and re-revision surgery (p < 0.0001). The Kaplan−Meier survivorship was 100% with aseptic loosening as the endpoint and 90% and 75% at five- and ten-year follow-up, respectively, with reoperation for any reason as the endpoint. Even cage reconstruction with bone allografts will fail eventually, and the bone stock of the acetabulum will improve after union and incorporation between host bone and allografts. The restored bone stocks will facilitate further revision surgery with hemispheric TM cups. The biological fixation between host bone and tantalum trabecular metal can provide longstanding stability of the TM cup. Conclusions: The results of our study offer a viable option for patients with failed cage reconstruction with bone allografts.

Application of structural allogenous bone graft in two-stage exchange arthroplasty for knee periprosthetic joint infection: a case control study.

BACKGROUND: Knee prosthetic joint infection (PJI) is a common but devastating complication after knee arthroplasty. The revision surgeries for knee PJI may become more challenging when it is associated with large bone defects. The application of structural bone allograft in knee revision surgeries with large bone defects is not a new technique. However, there is a lack of literature reporting its efficacy in PJI cases. This study aimed to investigate the outcome of structural fresh frozen allogenous bone grafts in treating patients in knee PJI with large bone defects. METHODS: We performed a retrospective cohort analysis of knee PJI cases treated with two-stage exchange arthroplasty at our institution from 2010 to 2016. 12 patients with structural allogenous bone graft reconstructions were identified as the study group. 24 patients without structural allograft reconstructions matched with the study group by age, gender, and Charlson comorbidity index were enrolled as the control group. The functional outcome of the study group was evaluated with the Knee Society Score (KSS). Treatment success was assessed according to the Delphi-based consensus definition. The infection relapse rate and implant survivorship were compared between groups. RESULTS: Revision knees with structural allograft presented excellent improvement in the KSS (33.1 to 75.4). There was no significant difference between infection relapse-free survival rate and prosthesis survival rate in the two groups. The 8-year prosthesis survival rate was 90.9% in the study group and 91% in the control group (p = 0.913). The 8-year infection relapse-free survival rate was 80 and 83.3% in the study group and control group, respectively (p = 0.377). CONCLUSION: The structural fresh frozen allogenous bone graft provided an effective way for bone defect reconstruction in knee PJI with an accountable survival rate. Meanwhile, using structural allografts did not increase the relapse rate of infection.

Revision Total Hip Arthroplasty with Primary Stem or Full-Porous-Coated Long Stem for Aseptic Femoral Component Loosening: A Matched-Pair Study.

BACKGROUND: Revision total hip arthroplasty (RTHA) for loosening the femoral stem is a technical challenge. Distally fixed, full-porous-coated long stems are widely accepted as the standard selection for these revisions. However, the success of primary stems in RTHA is not well known. METHODS: This study enrolled 24 patients with aseptic loosening of the femoral stem who underwent RTHA using primary stems. Another 72 patients with aseptic loosening who underwent RTHA using full-porous-coated long stems were matched in terms of operation date, proximal femoral bone stock (Paprosky classification), sex, and age. The primary and secondary outcomes of failure were the need for revision for any reason and the radiographic change in the stem respectively. RESULTS: In the primary stem group, one patient had a periprosthetic fracture and received a second RTHA 2 years after the previous one. The primary outcome's 5-and 10-year survival rates were both 95.8%. For the matched comparison group, one patient had an immediate periprosthetic fracture of the femoral shaft requiring further open reduction internal fixation surgery. Another patient had a full-porous-coated long stem breakage 6 years postoperatively, which required a second RTHA. The primary outcome's 5-and 10-year survival rates were 98.6% and 97.2%, respectively. CONCLUSION: Primary stems can achieve non-inferior clinical success compared to a full-porous-coated long stem for aseptic stem loosening RTHA in patients with adequate proximal femoral bone stock.

Treatment of knee osteoarthritis with intra-articular injection of allogeneic adipose-derived stem cells (ADSCs) ELIXCYTE®: a phase I/II, randomized, active-control, single-blind, multiple-center clinical trial.

OBJECTIVE: To evaluate the safety and efficacy of intra-articular (IA) injection of allogeneic adipose-derived stem cells (ADSCs) ELIXCYTE® for knee osteoarthritis. METHODS: This was a patient-blind, randomized, active-control trial consisted of 4 arms including hyaluronic acid (HA) control and 3 ELIXCYTE® doses. A total of 64 subjects were screened, and 57 subjects were randomized. The primary endpoints included the changes from baseline to post-treatment visit of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score at Week 24 and the incidence of adverse events (AEs) and serious adverse events (SAEs). RESULTS: No ELIXCYTE®-related serious adverse events were reported during 96 weeks of follow-up and no suspected unexpected serious adverse reaction (SUSAR) or death was reported. The changes of the primary endpoint, WOMAC pain score at Week 24, showed significant differences in all ELIXCYTE® groups, as well as in HA groups between post-treatment visit and baseline. The ELIXCYTE® groups revealed significant decreases at Week 4 compared to HA group in WOMAC total scores, stiffness scores, functional limitation scores suggested the potential of ELIXCYTE® in earlier onset compared to those from HA. The significant differences of visual analog scale (VAS) pain score and Knee Society Clinical Rating System (KSCRS) functional activities score at Week 48 after ELIXCYTE® administration suggested the potential of ELIXCYTE® in the longer duration of the effectiveness compared to HA group. CONCLUSIONS: ELIXCYTE® for knee osteoarthritis treatment was effective, safe, and well-tolerated. The efficacy results were showed that ELIXCYTE® conferred the earlier onset of reductions in pain scores and improvements in functional scores than HA group. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02784964. Registered 16 May, 2016-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02784964.

Ibudilast Mitigates Delayed Bone Healing Caused by Lipopolysaccharide by Altering Osteoblast and Osteoclast Activity.

Bacterial infection in orthopedic surgery is challenging because cell wall components released after bactericidal treatment can alter osteoblast and osteoclast activity and impair fracture stability. However, the precise effects and mechanisms whereby cell wall components impair bone healing are unclear. In this study, we characterized the effects of lipopolysaccharide (LPS) on bone healing and osteoclast and osteoblast activity in vitro and in vivo and evaluated the effects of ibudilast, an antagonist of toll-like receptor 4 (TLR4), on LPS-induced changes. In particular, micro-computed tomography was used to reconstruct femoral morphology and analyze callus bone content in a femoral defect mouse model. In the sham-treated group, significant bone bridge and cancellous bone formation were observed after surgery, however, LPS treatment delayed bone bridge and cancellous bone formation. LPS inhibited osteogenic factor-induced MC3T3-E1 cell differentiation, alkaline phosphatase (ALP) levels, calcium deposition, and osteopontin secretion and increased the activity of osteoclast-associated molecules, including cathepsin K and tartrate-resistant acid phosphatase in vitro. Finally, ibudilast blocked the LPS-induced inhibition of osteoblast activation and activation of osteoclast in vitro and attenuated LPS-induced delayed callus bone formation in vivo. Our results provide a basis for the development of a novel strategy for the treatment of bone infection.

Increased incidence, morbidity, and mortality in cirrhotic patients with hip fractures: A nationwide population-based study.

OBJECTIVES: Hip fractures mostly require surgical treatment and are associated with increased health-care costs and mortality rates. Patients with cirrhosis have low bone marrow density and inferior immune status which contribute to a higher fracture rate and higher surgical complication rate. This population-based study evaluated the prevalence, complication, and mortality rates due to hip fractures in cirrhotic patients. METHODS: Taiwan National Health Insurance Research Database data were used. The study group included 117,129 patients with hip fractures diagnosed from 2004 to 2010, including 4048 patients with cirrhosis. The overall prevalence, morbidity, and mortality rates of the cirrhosis group with hip fractures were compared with the rates of a general group with hip fractures. RESULTS: The cirrhosis group patients were younger than the general group patients (71.2 vs. 73.96 years, p < 0.001). The annual incidence of hip fractures in the cirrhosis and general groups was 46-54 and 7-7.5 per 10,000 person-years, respectively, with an incidence rate ratio of 6.95 (95% confidence interval 6.74-7.18). The rates of infection, urinary tract infection, and peptic ulcer disease were higher in the cirrhosis group (3.46% vs. 1.91%, 9.56% vs. 9.11%, and 8.05% vs. 3.55%, respectively; all p < 0.001). The mortality rate after hip fracture was also higher in the cirrhosis group than in the general group (within 3 months: 8.76-12.64% vs. 4.96-5.30% and within 1 year: 29.72-37.99% vs. 12.84-14.57%). Conclusion: Cirrhotic patients with hip fractures were relatively younger; had a seven times higher annual hip fracture incidence; had higher complication rates of infection, urinary tract infection, and peptic ulcer disease; and had two to three times higher a mortality rate at 3 months and 1 year. Clinicians should pay particular attention to the possibility of osteoporosis and hip fractures in patients with liver cirrhosis. LEVEL OF EVIDENCE: Level III, case-control study.

Lipoteichoic Acid Accelerates Bone Healing by Enhancing Osteoblast Differentiation and Inhibiting Osteoclast Activation in a Mouse Model of Femoral Defects.

Lipoteichoic acid (LTA) is a cell wall component of Gram-positive bacteria. Limited data suggest that LTA is beneficial for bone regeneration in vitro. Thus, we used a mouse model of femoral defects to explore the effects of LTA on bone healing in vivo. Micro-computed tomography analysis and double-fluorochrome labeling were utilized to examine whether LTA can accelerate dynamic bone formation in vivo. The effects of LTA on osteoblastogenesis and osteoclastogenesis were also studied in vitro. LTA treatment induced prompt bone bridge formation, rapid endochondral ossification, and accelerated healing of fractures in mice with femoral bone defects. In vitro, LTA directly enhanced indicators of osteogenic factor-induced MC3T3-E1 cell differentiation, including alkaline phosphatase activity, calcium deposition and osteopontin expression. LTA also inhibited osteoclast activation induced by receptor activator of nuclear factor-kappa B ligand. We identified six molecules that may be associated with LTA-accelerated bone healing: monocyte chemoattractant protein 1, chemokine (C-X-C motif) ligand 1, cystatin C, growth/differentiation factor 15, endostatin and neutrophil gelatinase-associated lipocalin. Finally, double-fluorochrome, dynamic-labeling data indicated that LTA significantly enhanced bone-formation rates in vivo. In conclusion, our findings suggest that LTA has promising bone-regeneration properties.

Teriparatide as nonoperative treatment for femoral shaft atrophic nonunion: A case report.

BACKGROUND: Femoral shaft fractures are a common type of fracture among adults and have high union rates. However, clinical decisions are difficult to make because of the different types of nonunions. Atrophic nonunion usually requires revision surgery combined with bone grafting. Furthermore, no study of teriparatide administration for femoral atrophic nonunion have been previously reported. CASE SUMMARY: A 60-year-old woman had a right femoral shaft fracture due to a traffic accident, and she immediately underwent closed reduction and internal fixation surgery with an intramedullary nailing. However, after 6 mo of rehabilitation, the fracture site showed no signs of healing, and her condition was diagnosed as atrophic nonunion. Subsequently, teriparatide was administered for 6 mo. Complete union was observed at the fracture site 6 mo after teriparatide discontinued. CONCLUSION: The use of teriparatide can be a promising treatment to improve the healing of nonunion fractures.

Revision Total Hip Arthroplasty for Paprosky Type III Acetabular Defect With Structural Allograft and Tantalum Trabecular Metal Acetabular Cup.

There are several surgical options for addressing Paprosky type III acetabular defects during revision total hip arthroplasty. In physiologically young and active patients, using structural bone graft to restore bone defects and provide adequate initial support for the revision acetabular component is one such option. This study reports the mid-term results of using a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. A retrospective analysis was performed of the data collected for 20 consecutive hips in 20 patients (mean age, 56.2 years; range, 43-68 years) with minimum 3-year follow-up (mean, 5.4 years; range, 3.3-10.3 years) who had a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. Only 1 hip had cup migration, which was less than 3 mm in vertical and less than 5° in inclination and recognized as loosening without symptoms. All grafts showed good incorporation with trabecular bridging over the graft and host bone. The mean modified Harris hip score showed significant improvement, from 29.7 (range, 11-52) preoperatively to 84.1 (range, 77-91) at the latest follow-up (P<.05). The use of a structural allograft combined with a tantalum trabecular metal acetabular cup in acetabular revision for Paprosky type III defects had a satisfactory mid-term clinical result. This is a viable option for patients with large acetabular shelf defects. [Orthopedics. 2018; 41(6):e861-e867.].

Two-stage revision arthroplasty for Mycobacterium Tuberculosis periprosthetic joint infection: An outcome analysis.

BACKGROUND: Mycobacterium tuberculosis periprosthetic joint infection (TBPJI) is a rare complication of hip/knee joint arthroplasty. The outcomes of hip/knee TBPJI treatment are still unreported. The objective of this study was to investigate the outcomes of hip/knee TBPJI following treatment with two-stage exchange arthroplasty. MATERIALS AND METHODS: From 2003 to 2013, 11 patients with TBPJI (six hips and five knees) were treated with two-stage exchange arthroplasty at our institution. We collected and analyzed variables including demographic data, comorbidities, microbiological data, duration of symptoms, and types of antibiotic used in bone cement. RESULTS: At the most recent follow-up, the success rate of two-stage exchange arthroplasty was 63.3% (7 of 11). All five knee treatments resulted in infection eradication and successful prosthesis reimplantation. However, only two hip TBPJI treatments resulted in successful outcomes; two patients died and two experienced chronic infection. Overall, secondary bacterial infections were common in patients with TBPJI (5 of 11 cases, 45.5%). Streptomycin in bone cement increased the success rate (83.33% vs. 40%). CONCLUSION: More than one third of the patients treated with two-stage exchange arthroplasty for TBPJI showed infection relapse or uncontrolled infection. Streptomycin-loaded interim cement spacers appeared to help ensure successful treatment. Routine M. tuberculosis culture is recommended when treating TBPJI in areas of high tuberculosis prevalence.

Vancomycin and Ceftazidime in Bone Cement as a Potentially Effective Treatment for Knee Periprosthetic Joint Infection.

BACKGROUND: The aim of this study was to determine the optimal formulation of antibiotic-loaded bone cement for knee periprosthetic joint infection. We used both in vitro and in vivo models incorporating various broad-spectrum antibiotics and tested their efficacy against gram-positive and gram-negative bacteria. METHODS: Bone cement specimens loaded with 4 g of either vancomycin or teicoplanin and 4 g of ceftazidime, imipenem, or aztreonam were studied to measure their in vitro antibiotic release characteristics and antibacterial capacities against methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Bone cement spacers loaded with the antibiotics with the superior in vitro antibacterial capacity were then implanted into 8 patients (4 women and 4 men between 51 and 79 years of age) diagnosed with chronic knee periprosthetic joint infection. The antibiotic concentrations and antibacterial activities in the joint fluid at the site of the infection were measured following spacer implantation. RESULTS: Cement samples loaded with vancomycin and ceftazidime exhibited in vitro antibacterial activity against the test microorganisms that lasted for as long as or longer than that of cement loaded with the other antibiotic combinations. Joint fluid samples exhibited activity against bacteria including American Type Culture Collection (ATCC) strains and clinically isolated strains. CONCLUSIONS: Bone cement loaded with vancomycin and ceftazidime provided broad-spectrum antibacterial capacity both in vitro and in vivo and was shown to be a potentially effective therapeutic measure in the treatment of knee periprosthetic joint infections. CLINICAL RELEVANCE: This study confirmed the potential effectiveness of drug delivery from bone cement spacers impregnated with vancomycin and ceftazidime.

Superior Survivorship of Cementless vs Cemented Diaphyseal Fixed Modular Rotating-Hinged Knee Megaprosthesis at 7 Years' Follow-Up.

BACKGROUND: Total knee arthroplasty in the presence of a huge bone and soft-tissue defect is always a challenge. A rotating-hinged (RH) megaprosthesis is indicated for extensive soft-tissue loss with a huge bone defect such as a primary or metastatic neoplasm of the bone, repeat periprosthetic joint infection, or extensive trauma of the knee. However, the reported survivorship of RH megaprostheses is unsatisfactory. The aim of this study was to evaluate the survivorship of megaprostheses and the factors that contribute to implant survival. METHODS: A total of 103 RH knee megaprostheses were implanted in 85 patients between January 2001 and June 2013. Each prosthesis was a modular custom-made (CM) cemented or cementless fixed total knee system (United USTAR system). Clinical results and prosthesis survivorship were evaluated between the 2 groups. RESULTS: The overall survivorship of this CM knee megaprosthesis was 91% at 2 years, 83% at 5 years, and 68% at 10 years. The cumulative component survivorship was 87% in the cemented group and 96% in the cementless group at 2 years compared with 75% in the cemented group and 94% in the cementless group at 5 years. The failure mechanism included loosening in 5 and breakage in 6 patients in the cemented stem group. The survivorship of the cementless fixed component was significantly superior to that of the cemented fixed component. CONCLUSION: Our data suggest that modular RHCM knee megaprosthesis provides an acceptable clinical result. A diaphyseal long stem with cementless fixation was more reliable and durable than its cemented counterpart.

Metal ion concentrations and semen quality in patients undergoing hip arthroplasty: A prospective comparison between metal-on-metal and metal-on-polyethylene implants.

PURPOSE: The widespread usage of metal-on-metal (MoM) articulations in total hip arthroplasty (THA) has been tempered by concerns of increased metal ion production. The purpose of the study is to evaluate the influence of metal ion exposure on semen quality in young male patients undergoing THA. METHODS: Male patients who were scheduled for unilateral THA and aged between 20 and 45 years were prospectively enrolled. Patients were sorted into MoM and metal-on-polyethylene (MoP) groups with equal case number. Semen and blood metal ion levels were measured and sperm analysis was performed before, 6 months after, and 1 year after surgery. RESULTS: Compared to preoperative baseline, patients (n = 50) in both groups had increased cobalt (Co) and chromium (Cr) concentrations in blood and seminal fluid after surgery. Between-group comparisons at 6 months and 1 year after surgery showed that patients in the MoM group both had a greater Co concentration in blood and semen and a greater Cr concentration in blood and semen. Patients receiving MoM prosthesis had a reduced percentage of morphologically normal sperm, and decreases from the preoperative level (44.7%) were significant at 6 months (36.8%, p = 0.03) and 1 year (33.8%, p = 0.004). CONCLUSIONS: Our data shows a significantly greater concentration of metal ion in blood and semen in patients with MoM prosthesis with a reduced percentage of morphologically normal sperm. Despite small effects on sperm quality, some concerns remain. Further studies are necessary to determine sources of metal ion and to investigate effects on male fertility.

Intra-articular bupivacaine reduces postoperative pain and meperidine use after total hip arthroplasty: a randomized, double-blind study.

One hundred patients receiving unilateral total hip arthroplasty (THA) were randomized to receive an intra-articular injection of 300mg bupivacaine or normal saline after completion of surgery. Pain scores of the bupivacaine group were significantly lower than those of the control group the first 12hours postoperatively (all, P<0.001). A significantly lower dose of meperidine was used in the study group than in the control group the first 24hours postoperatively (median, 25 vs. 45mg, P<0.001). Nineteen patients in the study group required meperidine the first day after surgery, as compared to 45 patients in the control group. We conclude that intra-articular injection of bupivacaine after THA reduces pain and meperidine use in the first 12hours after surgery.

What is the success of treatment of hip and knee candidal periprosthetic joint infection?

BACKGROUND: Fungal infection at an arthroplasty site is rare and poses a therapeutic challenge. To the best of our knowledge, no reports have been published thus far on the success rate of prosthesis reimplantation after fungal prosthetic joint infections. QUESTIONS/PURPOSES: We asked: (1) What is the success rate in terms of infection eradication using a two-stage exchange arthroplasty in patients with hip or knee fungal periprosthetic joint infections, particularly focusing on Candida infections? (2) What patient-, infection-, and treatment-related variables are associated with the success or failure of treatment? METHODS: From January 2000 to December 2010, 16 patients with hip or knee candidal periprosthetic joint infections were treated with two-stage exchange arthroplasty at our institute. Treatment success was defined as a well-functioning joint without relapse of candidal infection after prosthesis reimplantation, while treatment failure was defined as uncontrolled or relapse of candidal infection or mortality. Variables, including age, sex, comorbidities, microbiology, antimicrobial agents used, and operative methods, were analyzed. Minimum followup was 28 months (mean, 41 months; range, 28-90 months). RESULTS: At latest followup, the treatment failed to eradicate the infection in eight of the 16 patients, and there were four deaths related to fungemia. Four patients required permanent resection arthroplasty owing to uncontrolled or recurrent candidal infections. All eight patients (50% successful rate) who had their infections eradicated and successful prosthesis reimplantation had prolonged treatment with oral fluconazole before (mean, 8 months) and after (mean, 2.2 months) prosthesis reimplantation. The antifungal therapy correlated with successful treatment. Renal insufficiency, hypoalbuminemia, anemia, and chronic obstructive pulmonary disease were significantly more prevalent in the treatment-failure group than in the treatment-success group. CONCLUSIONS: Half of the patients treated with two-stage exchange arthroplasty for fungal periprosthetic joint infections had recurrence or lack of control of the infection. A prolonged antifungal therapy appeared to be essential for successful treatment of candidal periprosthetic joint infections. The presence of renal insufficiency, hypoalbuminemia, anemia, or chronic obstructive pulmonary disease might be associated with a poor outcome.