Use of Bacteria to Activate Ground-Granulated Blast-Furnace Slag (GGBFS) as Cementless Binder

Ground-granulated blast-furnace slag (GGBFS) can be used as a cementless binder after activation. Recent approaches to activate GGBFS have focused on chemical methods that use NaOH, KOH, and CaO. This study introduces the use of bacteria to activate GGBFS as a biological approach. The presence of bacteria (volumetric ratio), curing temperature (23 °C and 60 °C), and number of curing days (3, 7, and 28 d) are investigated. The use of urea is considered owing to the possibility of calcium carbonate formation. The activated GGBFS is evaluated in the form of a cube (5 cm × 5 cm × 5 cm) for its strength, mineral identification, and pore size distribution. A brick (19 cm × 9 cm × 5.7 cm) is prefabricated to see the feasibility of commercializing bacteria-activated GGBFS based on water absorption and strength measurements. All results are compared with those of water-activated GGBFS. The results indicate that the use of urea inhibits the strength improvement of bacteria-activated GGBFS. Bacterial suspension enhances the GGBFS strength at a curing temperature of 60 °C. Mineral identification tests show that the strength increase is primarily due to the formation of calcite. The compressive strength satisfies the commercial standard of concrete bricks; however, the water absorption rate must be resolved.     

Redefining Indications for Modern Cementless Total Knee Arthroplasty: Clinical Outcomes and Survivorship in Patients >75 Years Old

BackgroundMost studies on cementless total knee arthroplasty (TKA) have excluded patients >75 years due to concerns that older patients have poorer bone mineral density and osteogenic activity. This study compared the midterm outcomes and survivorship of cemented and cementless TKA of the same modern design performed in patients >75 years.MethodsWe identified a consecutive series of 120 primary cementless TKA performed in patients >75 years. Each case was propensity score matched 1:3 with 360 cemented TKA of the same modern design based on age, sex, body mass index, Charlson Comorbidity Index, bilateral procedures, liner type, and year of surgery. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Short Form-12 (SF-12) were collected preoperatively, at 6 months and 2 years. Implant survivorship was recorded at mean 4.2 years (range, 2.0-7.9).ResultsMean age was 79.0 ± 3.4 years (range, 75-92) in the cemented cohort and 78.9 ± 3.5 (range, 75-91) in the cementless cohort (P = .769). There was no difference in final postoperative scores or improvement in scores at 2 years. The percentage of patients that met the minimal clinically important difference was also similar (KOOS-JR, 68.9% vs 69.2%, P = .955; SF-12 Physical, 71.7% vs 66.7%, P = .299). Seven-year survivorship free from aseptic revision was 99.4% for cemented knees and 100% for cementless knees (log-rank, P = .453).ConclusionPatients over 75 years undergoing cementless or cemented TKA of the same modern design had comparable outcomes and survivorship in the midterm. The theoretical risks of cementless fixation in this age group were not realized in this study.     

Fracture of the ceramic head in total hip arthroplasty: Report of two cases

This article reports two cases of fracture of the ceramic head component in total cementless hip arthroplasty. There was no history of difficulty prior to the component fracture, neither during the operation nor during daily use, and in one of the patients, no history of trauma was observed.     

The Change in Posterior Tibial Slope After Cementless Unicondylar Knee Arthroplasty

BackgroundThe posterior tibial slope (PTS) is an important factor in patients undergoing unicondylar knee arthroplasty. It is an area subjected to high shear and compressive forces. Our objective is to investigate the changes taking place on the tibial slope of cementless unicondylar knee arthroplasties and define its relationship with functional scores.MethodsPatients undergoing a cementless unicondylar knee arthroplasty between January 2011 and July 2019 were selected. Exclusion criteria were lack of at least 1 year of follow up, loss to follow-up for any reason, and revision of a metallic component. Overall, 161 cases were included. Patients were analyzed using standard radiographs for changes in PTS, coronal positioning of the implant, and overhanging. Function was analyzed using Oxford Knee Score, Tegner Activity Scale, and Knee Society Score. Changes of the PTS were analyzed for statistical significance and for correlations with all the other variables.ResultsAll postoperative functional scores showed significant improvement (P < .05). Compared to the early postoperative values, increases of ≤5° were detected in 79% of all patients. The greater amount of slope change occurred during the first 6 months postoperatively. Statistical analysis revealed no significant relationship with functional scores of the knee, age, body mass index, overhanging, and coronal alignment of the tibial component.ConclusionThis study showed that, with time, minimal changes take place in the PTS of cementless unicondylar knee arthroplasty. The change mostly takes place during the first 6 months. These changes do not affect functional scores.     

Long-Term Survival (up to 34 Years) of Retained Cementless Anatomic Femoral Stem in Patients <50 Years Old

BackgroundThere is a paucity of studies longer than 30 years to determine clinical and radiographic results of retained cementless anatomic stem. The purpose of this study is to determine the long-term (up to 34 years) survival rate of the retained cementless anatomic femoral stem in patients <50 years of age.MethodsIsolated cup revision was performed with retaining primary cementless anatomic femoral stem in 206 patients (149 men and 57 women). Clinical and radiographic results were monitored at each follow-up. At the latest follow-up, computed tomography scans were carried out in all hips to determine the prevalence of osteolysis. The mean follow-up of the retained femoral stem was 30.3 years (range 27-34). The mean follow-up of the revised cup was 25.5 years (range 22-29).ResultsThe mean Harris Hip Score was 91 ± 7.8 points (range 71-100) and the mean Western Ontario and McMaster Universities Osteoarthritis score was 16 ± 7 points (range 7-34) at the final follow-up. The mean University of California, Los Angeles activity score was 7 ± 4 points (range 5-10) at the final follow-up. The overall survival rate of retained cementless femoral stems was 98.9% (95% confidence interval 91-100) at 30.3 years. The survival rate of the revised cup was 93% (95% confidence interval 89-98) at 25.5 years.ConclusionThe rate of aseptic loosening of already osseointegrated femoral stem remains low with ceramic-on-ceramic bearing in young active patients.     

Risk Factors for Significant Radiolucent Line Development in a Fully Coated Hydroxyapatite Stem

BackgroundThe risk factors for and clinical impact of radiolucent lines (RLLs) in cementless total hip arthroplasty remain contentious. The aim of this work was to describe a method of classification that has clinical significance and to identify risk factors.MethodsA cohort of 288 subjects with unrevised Corail stems (DePuy Synthes, Warsaw, IN) were reviewed with radiographs and Oxford Hip Scores at 10 years. Based on clinical experience, three groups were defined; those with no RLLs (NoRLLs), those considered to have benign RLLs (BenRLLs), and those considered to have significant RLLs (SigRLLs). SigRLLs were then compared to BenRLLs and NoRLLs to determine the validity of this classification.ResultsOne hundred and nine (37.8%) had NoRLLs, 111 (38.5%) had BenRLLs, and 68 (23.6%) had SigRLLs. No significant difference apart from gender was noted between the occurrence of BenRLLs and NoRLLs after multinomial regression analysis, consequently the NoRLLs and BenRLLs groups were combined (NoSigRLLs) and compared to SigRLLs. Non-cross-linked polyethylene (odds ratio = 4.6, P < .001), collarless stem design (odds ratio = 9.4, P < .001), undersizing (odds ratio = 1.2, P = .028), and male sex (odds ratio = 2.1, P = .008) were risk factors for SigRLLs. Regression analysis also revealed that increasing age at operation decreased the likelihood of SigRLLs (P < .001). Patients with SigRLLs had significantly higher pain scores (P = .005) although overall Oxford Hip Scores were not significantly different (P = .364).ConclusionThe definition of SigRLLs proposed in this study was significantly associated with that of non-cross-linked polyethylene, absence of a collar, undersizing, and higher pain scores.     

Outcomes of Newer Generation Cementless Total Knee Arthroplasty: Beaded Periapatite-Coated vs Highly Porous Titanium-Coated Implants

Background

Newer generation cementless total knee arthroplasty (TKA) designs are available and have novel implant coatings. We evaluated and compared beaded periapatite (PA)-coated vs highly porous titanium-coated cementless TKAs. Specifically, we compared: (1) survivorship, (2) Knee Society Scores (KSSs) and range of motion, (3) complications, and (4) radiographic findings.

Delayed Total Hip Arthroplasty for Failed Acetabular Fractures: The Influence of Initial Fracture Management on Outcome After Arthroplasty

Background

Total hip arthroplasty (THA) provides a successful salvage option for failed acetabular fractures. The complexity of arthroplasty for a failed acetabular fracture will depend on the fracture pattern and the initial management of the fracture. Our objective was to compare the midterm outcome of THA between patients who presented with failed acetabular fractures following initial surgical or nonsurgical treatment.

Cementless Porous Tantalum Monoblock Tibia vs Cemented Modular Tibia in Primary Total Knee Arthroplasty: A Meta-Analysis

Background

With the introduction of new fixation systems and designs, there has been a recent reemergence of interest in cementless fixation of the tibial component in total knee arthroplasty. However, little is known regarding the clinical features and survivorship of the cementless porous tantalum monoblock tibial component compared to the conventional cemented modular tibial component.

Cumulative Long-Term Incidence of Postoperative Periprosthetic Femoral Fractures Using an Uncemented Tapered Titanium Hip Stem: 26- to 32-Year Results

Background

Although falling is becoming a major problem in the elderly, little is known about the long-term incidence of postoperative periprosthetic femoral fractures (PFF) after total hip arthroplasty (THA) using uncemented stems with a minimum follow-up of 26 years postoperatively.