The Delta III and Delta Xtend reverse shoulder arthroplasty-risk of revision and failure mechanisms: a report on 3650 cases from the Norwegian Arthroplasty Register 1994-2021.

BACKGROUND: The Delta reverse shoulder arthroplasty (RSA) is commonly used worldwide and is the most frequently used RSA in Norway. The aim of this registry-based study was to report 10- and 20-year implant survival, risk of revision, and reasons for revision in 2 consecutive time periods for Delta III (1994-2010) and Delta Xtend (2007-2021) prostheses. METHODS: We included 3650 primary RSAs reported to the Norwegian Arthroplasty Register: 315 Delta III (42% cemented stems) and 3335 Delta Xtend (88% cemented stems). We used Kaplan-Meier analyses to investigate implant survival. The reasons for revision were compared for the 2 designs and fixation technique. Factors that could influence the risk of revision, such as implant design, fixation technique, and patient factors, were investigated using Cox regression analyses with adjustments for age, sex, and diagnosis. RESULTS: Patients operated with Delta III were more likely to be diagnosed with inflammatory disease or fracture sequela, whereas acute fracture, osteoarthritis, and cuff arthropathy were the most frequent indications for Delta Xtend. Ten-year survival was 93.0% (95% confidence interval [CI]: 87.0-99.0) (cemented stem) and 81.6% (95% CI: 75.3-87.9) (uncemented stem) for Delta III and 94.7% (95% CI: 93.3-96.1) (cemented stem) and 95.7% (95% CI: 88.3-100) (uncemented stem) for Delta Xtend. Twenty-year survival for Delta III (uncemented stem) was 68.2% (95% CI: 58.8-77.6). Compared with DeltaXtend (cemented stem) at 10-year follow-up, we found a higher risk of revision for Delta III (uncemented stem) (hazard ratio [HR]: 2.9, 95% CI: 1.7-5.0), whereas no significant difference was found for Delta III (cemented stem) and Delta Xtend (uncemented stem). The most common reason for revision of Delta III (uncemented stem) was glenoid loosening followed by deep infection and instability. Instability was the most frequent revision cause for Delta Xtend (both cemented and uncemented stem). Men had an overall higher revision risk than women (HR: 2.8 [95% CI: 2.0-3.9]), and patients with fracture sequela had increased risk for revision (HR: 2.8, 95% CI: 1.7-4.7) compared with patients with osteoarthritis. DISCUSSION: We found that Delta III (uncemented stem) had a higher risk of revision compared with Delta Xtend (cemented stem). The risk of revision for glenoid component loosening was lower for Delta Xtend, but revisions due to instability/dislocation are still a concern. This register study cannot determine whether the differences found were caused by differences in implant design or other factors that changed during the study period. Risk of revision may have been affected by the indication for primary operation.

Geographical variation in orthopedic procedures in Norway: Cross-sectional population-based study.

BACKGROUND: Standardized surgery rates for common orthopedic procedures vary across geographical areas in Norway. We explored whether area-level factors related to demand and supply in publicly funded healthcare are associated with geographical variation in surgery rates for six common orthopedic procedures. METHODS: The present study is a cross-sectional population-based study of hospital referral areas in Norway. We included adult admissions for arthroscopy for degenerative knee disease, arthroplasty for osteoarthritis of the knee and hip, surgical treatment for hip fracture, and decompression with/without fusion for lumbar disk herniation and lumbar spinal stenosis in 2012-2016. Variation in age and sex standardized rates was estimated using extremal quotients, coefficients of variation, and systematic components of variation (SCV). Associations between surgery rates and the socioeconomic factors urbanity, unemployment, low-income, high level of education, mortality, and number of surgeons and hospitals were explored with linear regression analyses. RESULTS: Knee arthroscopy showed highest level of variation (SCV 10.3) and decreased in numbers. Variation was considerable for spine surgery (SCV 3.8-4.9), moderate to low for arthroplasty procedures (SCV 0.8-2.6), and small for hip fracture surgery (SCV 0.2). Higher rates of knee arthroscopy were associated with more orthopedic surgeons (adjusted coefficient 24.8, 95% confidence interval (CI): 2.7-47.0), and less urban population (adjusted coefficient -13.3, 95% CI: -25.4 to -1.2). Higher spine surgery rates were associated with more hospitals (adjusted coefficient 22.4, 95% CI: 4.6-40.2), more urban population (adjusted coefficient 2.1, 95% CI: 0.4-3.8), and lower mortality (adjusted coefficient -192.6, 95% CI: -384.2 to -1.1). Rates for arthroplasty and hip fracture surgery were not associated with supply/demand factors included. CONCLUSIONS: Arthroscopy for degenerative knee disease decreased in line with guidelines, but showed high variation of surgery rates. Socioeconomic factors included in this study did not explain geographical variation in orthopedic surgery.

Polycrystalline Diamond Coating on Orthopedic Implants: Realization and Role of Surface Topology and Chemistry in Adsorption of Proteins and Cell Proliferation.

Polycrystalline diamond has the potential to improve the osseointegration of orthopedic implants compared to conventional materials such as titanium. However, despite the excellent biocompatibility and superior mechanical properties, the major challenge of using diamond for implants, such as those used for hip arthroplasty, is the limitation of microwave plasma chemical vapor deposition (CVD) techniques to synthesize diamond on complex-shaped objects. Here, for the first time, we demonstrate diamond growth on titanium acetabular shells using the surface wave plasma CVD method. Polycrystalline diamond coatings were synthesized at low temperatures (∼400 °C) on three types of acetabular shells with different surface structures and porosities. We achieved the growth of diamond on highly porous surfaces designed to mimic the structure of the trabecular bone and improve osseointegration. Biocompatibility was investigated on nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD) coatings terminated either with hydrogen or oxygen. To understand the role of diamond surface topology and chemistry in the attachment and proliferation of mammalian cells, we investigated the adsorption of extracellular matrix proteins and monitored the metabolic activity of fibroblasts, osteoblasts, and bone-marrow-derived mesenchymal stem cells (MSCs). The interaction of bovine serum albumin and type I collagen with the diamond surfaces was investigated by confocal fluorescence lifetime imaging microscopy (FLIM). We found that the proliferation of osteogenic cells was better on hydrogen-terminated UNCD than on the oxygen-terminated counterpart. These findings correlated with the behavior of collagen on diamond substrates observed by FLIM. Hydrogen-terminated UNCD provided better adhesion and proliferation of osteogenic cells, compared to titanium, while the growth of fibroblasts was poorest on hydrogen-terminated NCD and MSCs behaved similarly on all tested surfaces. These results open new opportunities for application of diamond coatings on orthopedic implants to further improve bone fixation and osseointegration.

Computerized Navigation: A Useful Tool in Total Knee Replacement.

The purpose of computer assistance in a total knee replacement is to achieve optimal alignment, size, and positioning of the implant. The method is safe and accurate and may be particularly useful in cases with abnormal anatomy. DESCRIPTION: The classical computer-assisted system for total knee replacement was developed with real-time surgical navigation using infrared optical tracking arrays. The tracking arrays are attached to the tibial and femoral shafts, as well as to surgical tools, allowing the surgeon to move the tools relative to the knee. The computer-assisted systems allow the surgeon to combine the "measured resection" and "gap balancing" techniques.Step 1: Preoperative planning. Set up the computer and software with the manufacturer implant features and personal preferences.Step 2: Positioning and surgical exposure. Position the patient in order to optimize the camera view.Step 3: Fixation of marker pins. Fix the marker pins to the tibial and femoral shafts.Step 4: Registration of anatomical landmarks and mechanical axes. Move the limb and mark out the anatomical landmarks according to the instructions given by the computer.Step 5: Adaption to the best model. Continue to register the joint surface and anatomy to adapt the fittest pre-registered model to the knee.Step 6: Fine-tuning. The femoral and tibial components are adjusted in size, flexion, extension, rotation, slope, and positioning along the anterior-posterior axis.Step 7: Navigation of cutting blocks and ligament balancing. The cutting blocks are positioned with the assistance of computerized navigation, adjusting for the mechanical axis and ligament tension. The cuts are then performed. Implant trials are inserted, and remaining soft-tissue releases may be performed assisted by the computer. Final implantation is performed. ALTERNATIVES: Conventional knee replacement using intramedullary rods as guidance. RATIONALE: The alignment and positioning of the implant are improved with the use of computer navigation1-5. Abnormal anatomy, anatomical variants and deformities, and presence of previous fractures are easy to manage with the precise assistance from the computer. Thus, in many cases, computer assistance may be a useful tool. EXPECTED OUTCOMES: Computer-assisted navigation may optimize the precision and accuracy of the surgical procedure. Given the correct target, the outcome of total knee replacement may be more predictable with use of this tool; however, the impact on functional outcomes has not yet been proven to be clinically relevant in clinical trials, and the implant longevity has not been improved6-11. IMPORTANT TIPS: Use two 3-mm drill pins for fixation of the optical array to the tibia and femur.If pins are placed within the wound (not through separate stab incisions), plan the positioning relative to the implant to avoid obstruction of the trials.In severely osteoporotic patients, use bicortical fixation and handle the tissues and limb gently to avoid bumping or displacing the optical array as this will negatively alter the registration and reduce navigational accuracy.Make sure the reflective beads on the optical array are clean at all times and remove them (if using clip-on beads) when using the saw to avoid blood splatter.Train an assistant to press the screen buttons in the correct order and in accordance with the surgical progress.

A survivorship study of 838 total elbow replacements: a report from the Norwegian Arthroplasty Register 1994-2016.

BACKGROUND: The aim of this study was to present the long-term survivorship (20 years) of total elbow arthroplasty (TEA) for a relatively large population and to compare different prosthesis brands and patient subgroups. METHODS: Between 1994 and 2017, a total of 838 primary TEAs were reported to the Norwegian Arthroplasty Register. Implant survival was calculated using the Kaplan-Meier method. Risk differences were examined using Cox regression analyses and exact Cox regression for rare events. We compared the survivorship of the 8 most frequently used implant brands, the different diagnoses leading to TEA, and the influence of the fixation technique. RESULTS: The overall 5-, 10-, 15-, and 20-year survival rates for all elbow arthroplasties were 92%, 81%, 71%, and 61%, respectively. Risk factors for revision were a diagnosis of sequelae after trauma and cementless fixation of the ulna component. There were some differences between the implant brands. The Norway prostheses had higher survival compared with the Kudo after 15 years of follow-up (78% and 66%, respectively; P < .001). Among the implants with shorter follow-up, the IBP and NES had inferior survivorship compared with the Norway. The frequently used Discovery had promising survivorship up to 5 years. The most frequent reason for revision surgery was aseptic loosening, followed by defective polyethylene, infection, and dislocation. The revision causes were to some degree implant specific. CONCLUSION: Fairly good results in terms of prosthesis survival were obtained with TEA, although results were poorer than for knee and hip arthroplasties.

Improved survival for anatomic total shoulder prostheses.

BACKGROUND AND PURPOSE: Previously, implant survival of total shoulder prostheses was reported to be inferior to that of hemiprostheses. However, the use of total prostheses has increased in Norway due to reported good functional results. On this background, we wanted to study implant survival of 4 major shoulder prosthesis types in Norway between 1994 and 2012. PATIENTS AND METHODS: The study population comprised 4,173 patients with shoulder replacements reported to the Norwegian Arthroplasty Register, including 2,447 hemiprostheses (HPs), 444 anatomic total prostheses (ATPs), 454 resurfacing prostheses (RPs), and 828 reversed total prostheses (RTPs). Three time periods were compared: 1994-1999, 2000-2005, and 2006-2012. Kaplan-Meier failure curves were used to compare implant failure rates for subgroups of patients, and adjusted risks of revision were calculated using Cox regression analysis. RESULTS: For prostheses inserted from 2006 through 2012, the 5-year survival rates were 95% for HPs (as opposed to 94% in 1994-1999), 95% for ATPs (75% in 1994-1999), 87% for RPs (96% in 1994-1999), and 93% for RTPs (91% in 1994-1999). During the study period, the implant survival improved significantly for ATPs (p < 0.001). A tendency of better results with acute fracture and worse results in sequelae after previous fractures was seen in all time periods. INTERPRETATION: The 5-year implant survival rates were good with all prosthesis types, and markedly improved for anatomic total prostheses in the last 2 study periods. The better functional results with total shoulder prostheses than with hemiprostheses support the trend towards increased use of total shoulder prostheses.