Total hip arthroplasties in the Dutch Arthroplasty Register (LROI) and the Nordic Arthroplasty Register Association (NARA): comparison of patient and procedure characteristics in 475,685 cases

Background and purpose — Collaborations between arthroplasty registries are important in order to create the possibility of detecting inferior implants early and improve our understanding of differences between nations in terms of indications and outcomes. In this registry study we compared patient and procedure characteristics, and revision rates in the Nordic Arthroplasty Register Association (NARA) database and the Dutch Arthroplasty Register (LROI). Patients and methods — All total hip arthroplasties (THAs) performed in 2010–2016 were included from the LROI (n = 184,862) and the NARA database (n = 290,823), which contains data from Denmark, Norway, Sweden, and Finland. Descriptive statistics and Kaplan–Meier survival analyses based on all reasons for revision and stratified by fixation were performed and compared between countries. Results — In the Netherlands, the proportion of patients aged < 55 years (9%) and male patients (34%) was lower than in Nordic countries (< 55 years 11–13%; males 35–43%); the proportion of osteoarthritis (OA) (87%) was higher compared with Sweden (81%), Norway (77%), and Denmark (81%) but comparable to Finland (86%). Uncemented fixation was used in 62% of patients in the Netherlands, in 70% of patients in Denmark and Finland, and in 28% and 19% in Norway and Sweden, respectively. The 5-year revision rate for THAs for OA was lower in Sweden (2.3%, 95% CI 2.1–2.5) than in the Netherlands (3.0%, CI 2.9–3.1), Norway (3.8%, CI 3.6–4.0), Denmark (4.6%, CI 4.4–4.8), and Finland (4.4%, CI 4.3–4.5). Revision rates in Denmark, Norway, and Finland were higher for all fixation groups. Interpretation — Patient and THA procedure characteristics as well as revision rates evinced some differences between the Netherlands and the Nordic countries. The Netherlands compared best with Denmark in terms of patient and procedure characteristics, but resembled Sweden more in terms of short-term revision risk. Combining data from registries like LROI and the NARA collaboration is feasible and might possibly enable tracking of potential outlier implants.publishedVersio

The influence of preoperative determinants on quality of life, functioning and pain after total knee and hip replacement:A pooled analysis of Dutch cohorts

Background: Previous research has identified preoperative determinants that predict health related quality of life (HRQoL), functioning and pain after total knee or hip arthroplasty (TKA/THA), but these differed between studies and had opposite directions. This may be due to lack of power and not adjusting for confounders. The present study aims to identify the preoperative determinants that influence health related quality of life (HRQoL), functioning and pain after total knee or hip arthroplasty (TKA/THA). Methods: We pooled individual patient from 20 cohorts with OA patients data (n = 1783 TKA and n = 2400 THA) in the Netherlands. We examined the influence of age, gender, BMI and preoperative values of HRQoL, functioning and pain on postoperative status and total improvement. Linear mixed models were used to estimate the effect of each preoperative variable on a particular outcome for each cohort separately. These effects were pooled across cohorts using a random effects model. Results: For each increase in preoperative point in HRQoL, the postoperative HRQoL increased by 0.51 points in TKA and 0.37 points in THA (SF-36 scale). Similarly, each point increase in preoperative functioning, resulted in a higher postoperative functioning of 0.31 (TKA) and 0.21 (THA) points (KOOS/HOOS-ADL scale). For pain this was 0.18 (TKA) and 0.15 (THA) points higher (KOOS/HOOS-pain scale) (higher means less pain). Even though patients with better preoperative values achieved better postoperative outcomes, their improvement was smaller. Women and patients with a higher BMI had more pain after a TKA and THA. Higher age and higher BMI was associated with lower postoperative HRQoL and functioning and more pain after a THA.Conclusions: Patients with a better preoperative health status have better outcomes, but less improvement. Even though the independent effects may seem small, combined results of preoperative variables may result in larger effects on postoperative outcomes.</p

Neuromuscular Warm-Up is Associated with Fewer Overuse Injuries in Ballet Dancers Compared to Traditional Ballet-Specific Warm-Up

Neuromuscular warm-up exercises (NMWU) have been shown to prevent injuries. In dance, research on warming-up is scarce. We investigated warm-up habits among ballet dancers and the effects of NMWU and traditional ballet-specific warm-up (TBSWU) on injuries. Using a cross-sectional survey among ballet dancers over the age of 18 years, we recorded acute and overuse injuries sustained in the previous 2 years. Warm-up behavior was assessed through 28 items. Dancers were grouped into NMWU or TBSWU: NMWU was based on neuromuscular warm-up programs in sports science and included exercises improving strength, power, proprioception, sensorimotor control, or cardiovascular stimulus; and TBSWU consisted of stretching, dance-technical exercises, marking steps and running-through-choreographies, or stretching with tools. Separate linear regression analyses adjusted for confounding factors were performed for acute and overuse injuries. A total of 192 dancers (26.7 ± 7.82 years, 159 females, 132 professionals) reported 203 acute and 469 overuse injuries. In total, 47.4% of dancers always warmed up (mean duration 20.7 ± 13.2 minutes) based on stretching (63%), technical-exercises (58.9%), strength-training (54.7%), and the barre (53.6%); and 9.4% never warmed up. A total of 31 dancers (16.15%) were classified as TBSWU, 16 dancers (8.3%) for NMWU, and 145 dancers did combined exercises. Those in the NMWU group were associated with fewer overuse injuries compared to those in the TBSWU group (β = -2.34; 95%CI -3.54 to -1.14). No association was found with acute injuries. As in other athletes, NMWU might be protective against overuse injuries in dancers. Large-scale prospective cohort studies are needed to gain more insight into NMWU as a possible component of injury prevention in ballet

Migration of all-polyethylene compared with metal-backed tibial components in cemented total knee arthroplasty : A randomized controlled trial

Background and purpose — With a rapidly increasing population in need of total knee arthroplasty (TKA), there is renewed interest in cost-saving all-polyethylene designs. Differences between metal-backed and all-polyethylene designs in initial component migration assessed by radiostereometric analysis (RSA), a proven predictor for late aseptic loosening, have been scantily reported. The purpose of this study was to compare implant migration and clinical outcomes of all-polyethylene tibial components versus metal-backed trays of similar geometrical shape. Patients and methods — In this randomized controlled trial, 59 patients received a cemented Triathlon condylar-stabilizing implant (Stryker, Mahwah, NJ, USA) with either an all-polyethylene (n = 29) or a metal-backed tibial component (n = 30). RSA measurements and clinical scores (the Knee Society Score, Forgotten Joint Score, and Knee Osteoarthritis and Injury Outcome Score) were evaluated at baseline and postoperatively at 3, 12, and 24 months. A linear mixed-effects model was used to analyze the repeated measurements. Results — A statistically significant difference in mean migration after 2 years was found in favor of the all-polyethylene group, with a mean maximum total point motion of 0.61 mm (95% CI 0.49–0.74) versus 0.81 mm (95% CI 0.68–0.96) for the cemented group (p = 0.03). However, this difference was smaller and not statistically significant after post hoc adjustment for surgeon effect. Both groups showed comparable improvements on all clinical outcome scores over time. Interpretation — The Triathlon all-polyethylene tibial component showed less migration, suggesting a lower risk of late loosening as compared with its metal-backed counterpart. However, the found surgeon effect warrants further investigation

Association Between Surface Modifications for Biologic Fixation and Aseptic Loosening of Uncemented Total Knee Arthroplasties

Background: Various surface modifications are used in uncemented total knee arthroplasties (TKAs) to enhance bony ingrowth and longevity of implants. This study aimed to identify which surface modifications are used, whether they are associated with different revision rates for aseptic loosening, and which are underperforming compared to cemented implants. Methods: Data on all cemented and uncemented TKAs used between 2007 and 2021 were obtained from the Dutch Arthroplasty Register. Uncemented TKAs were divided into groups based on their surface modifications. Revision rates for aseptic loosening and major revisions were compared between groups. Kaplan-Meier, Competing-Risk, Log-rank tests, and Cox regression analyses were used. In total, 235,500 cemented and 10,749 uncemented primary TKAs were included. The different uncemented TKA groups included the following: 1,140 porous-hydroxyapatite (HA); 8,450 Porous-uncoated; 702 Grit-blasted-uncoated; and 172 Grit-blasted-Titanium-nitride (TiN) implants. Results: The 10-year revision rates for aseptic loosening and major revision of the cemented TKAs were 1.3 and 3.1%, and for uncemented TKAs 0.2 and 2.3% (porous-HA), 1.3 and 2.9% (porous-uncoated), 2.8 and 4.0% (grit-blasted-uncoated), and 7.9% and 17.4% (grit-blasted-TiN), respectively. Both type of revision rates varied significantly between the uncemented groups (log-rank tests, P &lt; .001, P &lt; .001). All grit-blasted implants had a significantly higher risk of aseptic loosening (P &lt; .01), and porous-uncoated implants had a significantly lower risk of aseptic loosening than cemented implants (P = .03) after 10 years. Conclusion: There were 4 main uncemented surface modifications identified, with different revision rates for aseptic loosening. Implants with porous-HA and porous-uncoated had the best revision rates, at least equal to cemented TKAs. Grit-blasted implants with and without TiN underperformed, possibly due to the interaction of other factors.</p

All-polyethylene versus metal-backed posterior stabilized total knee arthroplasty : similar 2-year results of a randomized radiostereometric analysis study

Background and purpose — The all-polyethylene tibial (APT) component, introduced in the early 1970s, was surpassed by metal-backed tibial (MBT) trays as the first choice for total knee arthroplasty (TKA). With improved polyethylene, the modern APT components can reduce costs, and have shown equivalent results in survivorship and early migration of the cruciate-retaining and cruciate-stabilizing designs. This study compares the 2-year migration of a similarly designed APT-posterior stabilized (PS) and a MBT-PS TKA, using radiostereometric analysis (RSA). Patients and methods — 60 patients were randomized to receive either an APT Triathlon PS or an MBT Triathlon PS TKA (Stryker, NJ, USA). Migration measured by RSA and clinical scores were evaluated at baseline and at 3, 12, and 24 months postoperatively. Repeated measurements were analyzed with a linear mixed model and generalized estimating equations. Results — The mean maximum total point movement (MTPM) at 3, 12, and 24 months was 0.41 mm (95% CI 0.33–0.50), 0.57 mm (0.44–0.70), and 0.56 mm (0.42–0.69) respectively in the MBT group and 0.46 mm (0.36–0.57), 0.61 mm (0.49–0.73), and 0.64 mm (0.50–0.77) in the APT group. 2 MBT and 1 APT implant were considered unstable at the 2-year follow-up. The KSS Knee score and KSS Function across 3, 12, and 24 months were comparable in both groups. Interpretation — For an APT-PS designed component, MTPM measured with RSA is comparable to the MBT-PS component after 2 years of follow-up. No differences in complications or clinical outcomes were found

All-polyethylene versus metal-backed posterior stabilized total knee arthroplasty : similar 2-year results of a randomized radiostereometric analysis study

Background and purpose — The all-polyethylene tibial (APT) component, introduced in the early 1970s, was surpassed by metal-backed tibial (MBT) trays as the first choice for total knee arthroplasty (TKA). With improved polyethylene, the modern APT components can reduce costs, and have shown equivalent results in survivorship and early migration of the cruciate-retaining and cruciate-stabilizing designs. This study compares the 2-year migration of a similarly designed APT-posterior stabilized (PS) and a MBT-PS TKA, using radiostereometric analysis (RSA). Patients and methods — 60 patients were randomized to receive either an APT Triathlon PS or an MBT Triathlon PS TKA (Stryker, NJ, USA). Migration measured by RSA and clinical scores were evaluated at baseline and at 3, 12, and 24 months postoperatively. Repeated measurements were analyzed with a linear mixed model and generalized estimating equations. Results — The mean maximum total point movement (MTPM) at 3, 12, and 24 months was 0.41 mm (95% CI 0.33–0.50), 0.57 mm (0.44–0.70), and 0.56 mm (0.42–0.69) respectively in the MBT group and 0.46 mm (0.36–0.57), 0.61 mm (0.49–0.73), and 0.64 mm (0.50–0.77) in the APT group. 2 MBT and 1 APT implant were considered unstable at the 2-year follow-up. The KSS Knee score and KSS Function across 3, 12, and 24 months were comparable in both groups. Interpretation — For an APT-PS designed component, MTPM measured with RSA is comparable to the MBT-PS component after 2 years of follow-up. No differences in complications or clinical outcomes were found

Inclination but not anatomical reconstruction is related with higher cobalt levels in MoM hip arthroplasty

Background:  Metal on Metal total hip arthroplasty is associated with elevated serum cobalt levels. In this study we investigate if there is a relation between the inclination angle of the cup and the anatomical reconstruction of the hip on the serum cobalt level.Methods: Postoperative cobalt serum levels were measured in 250 patients. On standardized radiographs inclination angle, lower limb length, lateral offset, center of rotation distance were evaluated. A difference of more than 5 millimeter compared to the preoperative situation was considered as a non-anatomical reconstruction.Results: For every 10 degrees increase in inclination  the cobalt level increased 14% (p=0.036).  Women with the same cup inclination angle showed 34% higher cobalt levels than men (p=0.013). No relation was found between the anatomical reconstruction and the serum cobalt levels.Conclusions: A higher inclination of the cup leads to higher serum cobalt levels, but a non-anatomical reconstruction has no influence on serum cobalt levels

The influence of lower-leg injury and knee arthroscopy on natural anticoagulants and fibrinolysis

Background: Patients with lower-leg injuries and those undergoing knee arthroscopy are at increased risk of developing venous thromboembolism. The mechanism is unknown, including the influence of lower-leg injury and knee arthroscopy on natural anticoagulant factors and fibrinolysis. Objectives: To study the effect of lower-leg injury and knee arthroscopy on plasma levels of anticoagulant and fibrinolytic factors. Methods: We applied the following 2 designs to investigate this effect: a cross-sectional study for lower-leg trauma and a before-and-after study for knee arthroscopy. Plasma samples of POT-CAST– and POT-KAST–randomized clinical trial participants (collected shortly after lower-leg trauma or before or after arthroscopy) were analyzed for clot lysis time and levels of antithrombin, tissue factor pathway inhibitor, protein C, free protein S, plasminogen, tissue plasminogen activator, plasminogen activator inhibitor 1, antiplasmin, thrombin activatable fibrinolysis inhibitor, plasmin-antiplasmin, and D-dimer. For the effect of lower-leg injury, samples of 289 patients were compared with preoperative samples of 293 arthroscopy patients, acting as controls using linear regression and adjusting for age, sex, body mass index, comorbidities, and diurnal variation. For the effect of knee arthroscopy, mean changes were calculated for 277 patients using linear mixed models adjusted for diurnal variation. Parameters other than CLT and D-dimer were measured in smaller subsets. Results: In lower-leg injury patients, most parameters were stable, whereas D-dimer increased. After arthroscopy, most parameters decreased (especially clot lysis time, D-dimer, plasminogen, and anticoagulant factors), whereas tissue plasminogen activator and thrombin activatable fibrinolysis inhibitor slightly increased. Conclusion: In contrast to lower-leg injury, knee arthroscopy was associated with decreased natural anticoagulant factor levels. Neither lower-leg injury nor knee arthroscopy affected in vivo fibrinolysis