Long-term antibacterial activity of silver-containing hydroxyapatite coatings against Staphylococcus aureus in vitro and invivo.

BACKGROUND: The potential of silver-containing hydroxyapatite (Ag-HA) coatings to prevent orthopaedic implant-associated infection was explored previously; however, the resistance of Ag-HA coatings to late-onset orthopaedic infections is unknown. This study aimed to evaluate the long-term Ag+ elution and antibacterial properties of the Ag-HA coatings through in vitro and in vivo experiments. METHODS: Ag-HA-coated disc specimens were immersed in fetal bovine serum (FBS) for six months. Ag concentration was measured over time using inductively coupled plasma-mass spectrometry to evaluate Ag release. The hydroxyapatite (HA)- or Ag-HA-coated disc specimens were immersed in FBS for 3 months to elute Ag+ for in vitro experiments. Methicillin-resistant Staphylococcus aureus (MRSA) suspensions were inoculated onto each disc; after 48 h, the number of colonies and the biofilm volume were measured. HA- or Ag-HA-coated disc specimens were inserted under the skin of Sprague-Dawley rats for three months for in vivo experiments. In in vivo experiment 1, specimens were inoculated with MRSA and the number of colonies was counted after 48 h. In in vivo experiment 2, the specimens were inoculated with bioluminescent S. aureus Xen36 cells, and bioluminescence was measured using an in vivo imaging system. RESULTS: The Ag-HA-coated disc specimens continued to elute Ag+ after six months. The biofilm volume in the Ag-HA group was lower than in the HA group. In in vitro and in vivo experiment 1, the bacterial counts in the Ag-HA group were lower than those in the HA group. In in vivo experiment 2, the bioluminescence in the Ag-HA group was lower than that in the HA group on days 1-7 after inoculation. CONCLUSIONS: The Ag-HA-coated discs continued to elute Ag+ for a long period and exhibited antibacterial activity and inhibition of biofilm formation against S. aureus. The Ag-HA coatings have the potential to reduce late-onset orthopaedic implant-associated infections.

Osteoconductivity and neurotoxicity of silver-containing hydroxyapatite coating cage for spinal interbody fusion in rats.

Background: The use of spinal instrumentation is an established risk factor for postoperative infection. To address this problem, we prepared silver-containing hydroxyapatite coating, consisting of highly osteoconductive hydroxyapatite interfused with silver. The technology has been adopted for total hip arthroplasty. Silver-containing hydroxyapatite coating has been reported to have good biocompatibility and low toxicity. However, no studies about applying this coating in spinal surgery have addressed the osteoconductivity and direct neurotoxicity to the spinal cord of silver-containing hydroxyapatite cages in spinal interbody fusion. Aim: In this study, we evaluated the osteoconductivity and neurotoxicity of silver-containing hydroxyapatite-coated implants in rats. Materials & Methods: Titanium (non-coated, hydroxyapatite-coated, and silver-containing hydroxyapatite-coated) interbody cages were inserted into the spine for anterior lumbar fusion. At 8 weeks postoperatively, micro-computed tomography and histology were performed to evaluate the osteoconductivity of the cage. Inclined plane test and toe pinch test were performed postoperatively to assess neurotoxicity. Results: Micro-computed tomography data indicated no significant difference in bone volume/total volume among the three groups. Histologically, the hydroxyapatite-coated and silver-containing hydroxyapatite-coated groups showed significantly higher bone contact rate than that of the titanium group. In contrast, there was no significant difference in bone formation rate among the three groups. Data of inclined plane and toe pinch test showed no significant loss of motor and sensory function in the three groups. Furthermore, there was no degeneration, necrosis, or accumulation of silver in the spinal cord on histology. Conclusions: This study suggests that silver-hydroxyapatite-coated interbody cages produce good osteoconductivity and are not associated with direct neurotoxicity.

Comparison of the clinical outcomes following total knee arthroplasty in osseous ankylosed and non-ankylosed knees using propensity-score matching.

OBJECTIVES: Few studies have compared the clinical outcomes and complications of total knee arthroplasty (TKA) in patients with and without osseous ankylosed knees. Thus, we investigated the clinical outcomes and complications of TKA in patients with osseous ankylosed knees, using a propensity-score matching method. METHODS: Thirteen knees in the osseous ankylosed-knees group and 13 knees in the non-ankylosed-knees group were included after excluding those with less than two years of follow-up or a lack of data and after propensity-score matching. The American Knee Society Score-knee (AKSS-knee), American Knee Society Score-function (AKSS-function), knee-flexion angle, knee-extension angle, knee range of motion (ROM) before and after TKA, and the number of knees with postoperative complications were evaluated as primary outcomes. RESULTS: The AKSS-knee, AKSS-function, knee-flexion angle, and knee ROM in the osseous ankylosed-knees group after TKA were significantly lower than those in the non-ankylosed-knees group. The knee-extension angle after TKA and number of knees with postoperative complications within two years were not significantly different between the two groups. CONCLUSIONS: The clinical results of TKA in patients with osseous ankylosed knees were inferior to those in patients with non-ankylosed knees.

Fragility fracture following total hip arthroplasty.

BACKGROUND: While periprosthetic fractures following total hip arthroplasty (THA) are a well-known phenomenon for orthopedic surgeons, fragility fractures following THA are also a significant, though less studied, concern. Furthermore, patients who have undergone THA have several additional risk factors for fragility fractures, including motor weakness, bone atrophy, and limping. The aims of this study were to evaluate the incidence of fragility fractures following THA and to clarify the characteristics of these fractures. METHODS: This study included 5678 primary THA procedures in 4589 female patients. This study evaluated body morphology data, disease type leading to THA, Japanese Orthopaedic Association hip score, range of motion of the hip joint, and medical history. Distal radius and patella fractures were defined as fragility fractures. Risk factors for fragility fractures after THA were calculated by comparing the fragility fracture group with the non-fracture group. RESULTS: Fifty-three fragility fractures were confirmed in 53 patients (distal radius fracture: 32 fractures in 32 patients, patella fracture: 21 fractures in 21 patients). In the univariate analysis, the following eight risk factors for fragility fractures were significantly different between the groups: height, weight, follow-up period, developmental dysplasia of the hip, primary osteoarthritis, abduction before THA, internal rotation before THA, and external rotation before THA. Medical histories were not significantly different between the groups. There was no difference in any study factor and in the time of occurrence between the radius fractures and patella fractures analyzed as fragility fractures. CONCLUSIONS: This study revealed that there are significant preoperative factors of fragility fractures following THA. These factors will serve as useful data for THA treatment strategies, preoperative explanations, and future studies.

Mid-term clinical outcomes and complications of primary total knee arthroplasty in hemodialysis patients: a retrospective comparative cohort study.

BACKGROUND: Numerous patients who receive hemodialysis (HD) undergo total knee arthroplasty (TKA) due to advanced knee joint arthritis. However, there are few studies that describe the clinical outcomes and complications of TKA in HD patients. This study investigated the mid-term results of TKA in patients undergoing HD. METHODS: This single-center retrospective study compared clinical and surgical outcomes following TKA in patients who were receiving HD with those who were not. We used propensity scores to match 21 knees of 18 patients who received HD to 706 knees of 569 patients who had not received HD, from a total of 727 knees (587 patients) that underwent primary unilateral TKA. The clinical outcomes were evaluated using the American Knee Society Score-knee (AKSS-knee) and AKSS-function scores. The primary surgical outcome measure was the number of knees with postoperative complications. RESULTS: In both the HD and non-HD groups, postoperative AKSS-knee and function scores significantly improved when compared to preoperative values. Postoperative AKSS-knee and function scores were not significantly different between the groups. The number of knees with postoperative complications was larger in the HD group than the non-HD group within the first postoperative month, 0-12 months, 12-24 months, 0-24 months, and two years after surgery. Additionally, in the HD group, more complications occurred in the first month than any subsequent month in the two years after surgery. CONCLUSIONS: TKA improves AKSS-knee and function scores equivalently for HD patients and non-HD patients. However, HD patients develop more complications after TKA, especially within the first month. Therefore, surgeons who perform TKA for HD patients should obtain informed consent after explaining the possible complications, and HD patients should be carefully observed following TKA.

Total hip arthroplasty using hydroxyapatite-coated cementless cup for rapidly destructive coxarthrosis: Minimum 10-year follow-up.

BACKGROUND: Performing total hip arthroplasty (THA) as early as possible is recommended for rapidly destructive coxarthrosis (RDC) as it causes pain that becomes progressively more severe. However, acetabular bone loss remains an issue in THA. Special devices, such as a Kerboull-type plate, may be used for acetabular bone defects, but the procedure is highly invasive and often the patients are elderly, further complicating matters. We retrospectively investigated the clinical and radiographic results of THA using conventional hydroxyapatite-coated cementless cup in RDC. METHODS: A total of 32 patients (35 hips) with RDC were enrolled in the study with a minimum 10-year follow-up. All THAs were performed using conventional hydroxyapatite-coated cementless cup. All patients were evaluated clinically according to the Harris hip score (HHS). Acetabular bone deficiency was classified according to the American Academy of Orthopaedic Surgeons (AAOS) classification. RESULTS: Eleven hips (31%) were AAOS type III, and none were type IV. Total HHS significantly improved from 36.5 to 79.4 (p < 0.01). Two cups exhibited loosening. The overall implant-associated survival rate after 10 years was 91.4%. CONCLUSIONS: Clinical results of THA using conventional cementless implants for patients with RDC were acceptable. Thus, THA using conventional cementless implant is an effective and safe surgery for patients with RDC, minimizing surgical stress.

Traumatic boutonniere deformity of the second toe caused by sumo wrestling: A case report.

INTRODUCTION: Traumatic boutonniere deformities of the fingers are well documented unlike those of the lesser toes. With few existing reports on boutonniere deformities of the lesser toes, the related pathology and treatment guidelines remain unclear. PRESENTATION OF CASE: We present a case of traumatic boutonniere deformity of the second toe caused by sumo wrestling in a 23-year-old man. A flexion deformity of the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint of the right second toe were observed, including a torn central slip and plantarly displaced lateral bands during surgery. Surgical repair of the extensor mechanism and temporary pinning led to good clinical results. DISCUSSION: Acute traumatic boutonniere deformity of the interphalangeal joint of the lesser toe is very rare. The mechanism of boutonniere deformity in this case is thought to be due to forced passive flexion exerted on an actively extended PIP joint, which is similar to that seen in fingers. CONCLUSION: We describe the pathophysiology of a case of boutonniere deformity of the lesser toe and suggest the effectiveness of surgical treatment.

Conventional Cementless Total Hip Arthroplasty for Hip Osteoarthritis after Distal Trochanteric Transfer: A Report of Two Cases.

Distal trochanteric transfer (DTT) has been widely performed to treat developmental dysplasia of the hip or Perthes disease. Total hip arthroplasty (THA) following DTT in patients with hip osteoarthritis is one of the most challenging procedures for hip surgeons, because great care must be taken regarding anatomical abnormalities of the greater trochanter and the soft tissue attached to the greater trochanter. To the best of our knowledge, there are no reports on THA after DTT. We herein report two cases of patients who underwent THA post DTT using cementless components. After THA, both patients developed abduction temporary contraction because of leg length extension and gluteus medius hypertension. However, in both cases, the contraction was reversible within two months and the final clinical result was good. Therefore, THA can be considered an effective and safe choice for treating osteoarthritis after DTT.

The combination of silver-containing hydroxyapatite coating and vancomycin has a synergistic antibacterial effect on methicillin-resistant Staphylococcus aureus biofilm formation.

AIMS: Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation. METHODS: Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 106 or 43.0 (SD 8.4) x 105 colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 106 or 72.0 (SD 4.2) x 105 CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting. RESULTS: Biofilms that formed on HA discs were thicker and larger than those on Ti discs, whereas those on Ag-HA discs were thinner and smaller than those on Ti discs. Viable bacterial counts in vivo revealed that Ag-HA combined with VCM was the most effective treatment. CONCLUSION: Ag-HA with VCM has a potential synergistic effect in reducing MRSA biofilm formation and can thus be useful for preventing and treating PJI.Cite this article: Bone Joint Res. 2020;9(5):211-218.

Antibacterial Activity of Ag-Hydroxyapatite Coating Against Hematogenous Infection by Methicillin-Resistant Staphylococcus aureus in the Rat Femur.

Several antibacterial materials have been developed to prevent periprosthetic joint infection and thus prevent serious complications for patients and surgeons. However, no study has addressed the activity of antibacterial materials against hematogenous infection. The present study evaluated the antibacterial activity of a silver-containing hydroxyapatite-coated implant against methicillin-resistant Staphylococcus aureus (MRSA) hematogenous infection. Implants coated with hydroxyapatite and silver-hydroxyapatite were inserted into rats' right and left femurs, respectively, after which the animals were infected with S. aureus via a tail vessel. About 107 colony-forming units was the optimal bacterial number for the establishment of S. aureus hematogenous infection. Bacterial loads and C-reactive protein in the blood were measured to confirm bacteremia and inflammation. Fourteen days after the infection, bacterial loads were statistically lower in the femurs containing silver-hydroxyapatite-coated implants than in those with hydroxyapatite-coated implants (p = 0.022). Thus, silver-hydroxyapatite-coated implants might provide antibacterial activity against MRSA hematogenous infection in the postoperative period. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2655-2660, 2019.

Medial Condyle Fracture (Kilfoyle Type III) of the Distal Humerus with Transient Fishtail Deformity after Surgery.

A "Fishtail deformity" is one of the well-known complications following pediatric lateral condyle or supracondylar fractures of the humerus. We herein report a case of medial condyle fracture (Kilfoyle type III) in an 11-year-old boy. He had a transient "fishtail deformity" of the trochlear groove after open reduction and internal fixation. As occurred in the current case, the bone remodeling and the improvement of ischemia of the trochlea after medial condyle fracture may be associated with the likelihood of recovery from transient "fishtail deformity."