Finnish Arthroplasty Register Research Articles

Risk factors for revision due to prosthetic joint infection following total knee arthroplasty based on 62,087 knees in the Finnish Arthroplasty Register from 2014 to 2020

Periprosthetic joint infection (PJI) is the commonest reason for revision after total knee arthroplasty (TKA). We assessed the risk factors for revision due to PJI following TKA based on the Finnish Arthroplasty Register (FAR). We analyzed 62,087 primary condylar TKAs registered between June 2014 and February 2020 with revision for PJI as the endpoint. Cox proportional hazards regression was used to estimate hazard ratios (HR) with 95% confidence intervals (CI) for the first PJI revision using 25 potential patient- and surgical-related risk factors as covariates. 484 knees were revised for the first time during the first postoperative year because of PJI. The HRs for revision due to PJI in unadjusted analysis were 0.5 (0.4-0.6) for female sex, 0.7 (0.6-1.0) for BMI 25-29, and 1.6 (1.1-2.5) for BMI > 40 compared with BMI < 25, 4.0 (1.3-12) for preoperative fracture diagnosis compared with osteoarthritis, and 0.7 (0.5-0.9) for use of an antimicrobial incise drape. In adjusted analysis the HRs were 2.2 (1.4-3.5) for ASA class III-IV compared with class I, 1.7 (1.4-2.1) for intraoperative bleeding ≥ 100 mL, 1.4 (1.2-1.8) for use of a drain, 0.7 (0.5-1.0) for short duration of operation of 45-59 minutes, and 1.7 (1.3-2.3) for long operation duration > 120 min compared with 60-89 minutes, and 1.3 (1.0-1.8) for use of general anesthesia. We found increased risk for revision due to PJI when no incise drape was used. The use of drainage also increased the risk. Specializing in performing TKA reduces operative time and thereby also the PJI rate.

Venous thromboembolism is rare after total hip and knee joint arthroplasty with long thromboprophylaxis in Finnish fast-track hospitals

IntroductionPharmacological thromboprophylaxis effectively prevents venous thromboembolism (VTE) after total knee (TKA) and total hip arthroplasty (THA). Less is known about the influence of fast-track arthroplasty on VTE risk. We conducted a register-based study to determine the incidence of VTE after fast-track TKA and THA in Finland using long thromboprophylaxis.Materials and methodsAll primary TKAs and THAs operated during 2015–2016 in 3 fast-track hospitals were identified from the Finnish Arthroplasty Register. Pulmonary embolism (PE) and deep vein thrombosis (DVT) diagnosed in this patient cohort within 90 days of surgery were identified from the Finnish Hospital Discharge Register. The recommended length of thromboprophylaxis was 10 to 14 days for TKA and 28 days for THA during study period.ResultsDuring the study period, 3 831 THAs, 4 394 TKAs and 286 bilateral TKAs (BTKAs) were performed. Of all these patients, 60% were females. Venous thromboembolism (VTE) incidence within 90 days of surgery was 0.3% (95% CI 0.2–0.4). These VTEs comprised 10 PEs and 15 DVTs. None of the VTE patients´ died within the 90-day period.ConclusionVTE incidence is low in Finnish fast-track TKA and THA patients with long thromboprophylaxis.

How Often Do Complications and Mortality Occur After Operatively Treated Periprosthetic Proximal and Distal Femoral Fractures? A Register-based Study.

The incidence of periprosthetic femoral fractures is increasing because of an increasing number of primary THAs and TKAs. High rates of complications and mortality are associated with periprosthetic fractures, but few studies have evaluated and compared the population-based incidences of these events after fractures. (1) What is the annual incidence of periprosthetic fractures treated with surgery in one hospital district in Finland? (2) How are those incidences changing over time? (3) What is the risk of complications, reoperations, and death after those injuries? This register-based study evaluated 2259 patients who underwent revision THA or TKA or any surgery for a femoral fracture between January 2004 and December 2016 at the only hospital in our district where these types of operations are performed. During the study period, the diagnosis and operation codes of the operated-on patients varied greatly, and they were somewhat inaccurate. We thus evaluated radiographs of all 2259 patients one by one, and created inclusion and exclusion criteria based on radiologic findings and medical records. Of those, 12% (279 of 2259) had periprosthetic fractures that met the inclusion criteria, and from these, we formed two study groups (periprosthetic proximal femur fractures, n = 171; periprosthetic distal femur fractures, n = 108). Eighty-eight percent (1980 of 2259) of the patients were excluded because they were treated for a condition other than periprosthetic femoral fracture. The follow-up period ended in December 2019 or at the time the patient died. To evaluate the population-based incidence, we drew the number of individuals with THA or TKA in the hospital district from the Finnish Arthroplasty Register and the Finnish Hospital Discharge Register. The characteristics of patients with operatively treated periprosthetic femoral fractures were evaluated in terms of age, gender, fracture type, implant type, and time from the index operation to periprosthetic fracture. The annual incidences of periprosthetic femoral fractures are summarized per 1000 person-years of individuals living with an implanted THA or TKA and per 100,000 individuals per year living in our hospital district. The risks of death, complications, and reoperations were evaluated for both groups, and comparisons were made in terms of patient characteristics. The mean annual incidence of operatively treated periprosthetic proximal femur fractures per 1000 people living with THA implants was 2.3 ± 0.9 (95% confidence interval 1.8 to 2.7) per year, and for those with periprosthetic distal femur fractures with TKA implants, it was 1.3 ± 0.6 (95% CI 1.0 to 1.7). There was an increasing trend in the incidence of periprosthetic proximal femur fractures from 1.6 to 3.8 (95% CI 1.8 to 2.8) per 1000 arthroplasties, and it increased from 0.4 to 1.7 (95% CI 2.4 to 4.4) for periprosthetic distal femur fractures between 2004 and 2016. The mean population-based incidence of periprosthetic proximal femur fractures per 100,000 person-years was 5.3 ± 2.2 (95% CI 4.1 to 6.4) per year, and for periprosthetic distal femur fractures, it was 3.4 ± 1.7 (95% CI 2.5 to 4.4). The incidence of periprosthetic proximal femur fractures related to 100,000 person-years increased from 3.2 to 8.9 (95% CI 3.9 to 6.6), while the incidence of periprosthetic distal femur fractures increased from 1.3 to 4.4 (95% CI 2.4 to 4.8) during the study period. The cumulative incidence of major complications after periprosthetic proximal femur fracture was 8.8% at 1 year (95% CI 5.1% to 13.6%) and 12.3% at 10 years (95% CI 7.5% to 18.4%), and after periprosthetic distal femur fracture, it was 7.4% at 1 year (95% CI 3.5% to 13.4%) and 9.3% at 10 years (95% CI 4.7% to 15.7%). The cumulative incidence of reoperation after periprosthetic proximal femur fracture was 10.5% at 1 year (95% CI 6.5% to 15.7%) and 13.5% at 10 years (95% CI 8.9% to 19.1%), and for periprosthetic distal femur fracture, it was 8.3% at 1 year (95% CI 4.1% to 14.5%) and 13.8% at 10% years (95% CI 7.8% to 21.4%). The cumulative incidence of death after periprosthetic proximal femur fracture was 8.2% at 1 year (95% CI 4.7% to 12.9%) and 47.3% at 10 years (95% CI 38.1% to 55.9%), and after periprosthetic distal femur fractures, it was 14.8% at 1 year (95% CI 8.8% to 22.2%) and 67.8% at 10 years (95% CI 56.3% to 76.9%). The increased use of THA and TKA has led to an increase in the incidence of operatively treated periprosthetic fractures, which means there will be more revisions in the future. Older age, frailty of these patients, and often-complicated fracture patterns are related to a high rate of complications, reoperations, and mortality. Healthcare systems must prepare for a large increase in revisions for periprosthetic fracture, which are morbid events for patients and costly ones for healthcare systems. Level III, therapeutic study.

No difference in implant survival between 28-mm M2a RingLoc metal-on-metal and metal-on-polyethylene total hip arthroplasty: results from the Finnish Arthroplasty Register.

Long-term outcome of small head (28 mm) metal-on-metal (MoM) total hip arthroplasty (THA) is available mainly for Metasul devices (Sulzer Medica, Winterthur, Switzerland). Biomet MoM THA was frequently used in Finland. Therefore, we assessed long-term survivorship of the M2a 28-mm RingLoc MoM THA (Biomet, Warsaw, IN, USA) and compared it with the metal-on-polyethylene (MoP) RingLoc THA from the same manufacturer. We conducted a register study based on THAs from the Finnish Arthroplasty Register performed between January 1, 2000 and December 31, 2007. 290 28-mm head M2a MoM THAs and 1,647 28-mm head MoP THAs (reference group) were included. The endpoint was revision for any reason, or revision for aseptic loosening, osteolysis, liner wear, or metallosis as one group. Kaplan-Meier survival estimates were calculated, and revision risks were assessed using a Cox multiple regression model, both with 95% confidence intervals (CI). No difference was found in the 15-year Kaplan-Meier survivorship between the 28-mm head M2a RingLoc MoM THA and the reference group for any reason for revision (87.7% [82.9-92.1] and 83.3% [81.0-85.3], respectively). The adjusted hazard ratio (HR) for any reason for revision for the MoM THA group compared with the reference group was at least equal or better (0.70 [0.48-1.02]). Both groups presented similar survival for revision for aseptic loosening of the cup, osteolysis, liner wear, or metallosis, at 96.2% (92.7-98.0) and 95.4% (93.9-96.5), respectively. In the long-term survival there was no difference between the M2a 28-mm RingLoc MoM THA and 28-mm MoP THA. Further follow-up regimens for M2a 28-mm RingLoc THA patients may be unnecessary, but long-term metal ion and radiological data is needed before any formal suggestions.

Decreased burden of revision hip replacements despite substantial rise in prevalence: a register-based analysis in Finland.

Background and purposeWhile the incidence of THR operations has been established, little is known about the prevalence or the ratio of the annual number of revision THRs to the total number of THRs in the general population. By combining data from nationwide registers, we calculated the annual prevalence of THRs and the revision burden caused by THR survivors in Finland.Patients and methodsAll primary THRs performed between 1980 and 2020 were identified from the Finnish Arthroplasty Register (FAR). Patient deaths were extracted from the Finnish Digital and Population Data Services Agency and THR revisions and removals from the FAR and the Finnish Hospital Discharge Register. We analyzed annual THR prevalence by dividing the number of THRs by the population aged 40 or older and the revision burden factor (RBF) by dividing the annual number of revisions by the total number of primary and revision THRs in the population. The proportions of bilateral implants and patients with THRs performed more than 10 years earlier (older THRs) were identified.ResultsTHR prevalence in Finland increased rapidly, reaching 3.6% in 2020. Between 2010 and 2020, the number of THRs increased by 50% and the prevalence of THRs by 38%. In 2020, the proportion of bilateral THRs had risen to 29% and the proportion of patients with older THRs to 36%. The RBF decreased between 1996 and 2020 from 3.1% to 1.3% (age- and sex-adjusted proportion ratio PR 0.42 [95% CI 0.39–0.45]).InterpretationDespite the decrease in the RBF, the rapidly increasing prevalence of THRs potentially increases the number of revisits and revisions and thus poses a challenge for healthcare in the future.

Rapid rise in prevalence of knee replacements and decrease in revision burden over past 3 decades in Finland: a register-based analysis.

Background and purposeThe prevalence of knee joint replacements (KJR) has been less investigated in situations where the increase in incidence is known. This study investigated the annual and population-based prevalence of KJR and the relationship between the prevalence of KJRs and the incidence of revision surgery.Patients and methodsAll KJRs performed between 1980 and 2020 were identified from the Finnish Arthroplasty Register (FAR). KJR revisions and removals were extracted from the FAR and hospital discharge registers and patient deaths from Finnish Digital and Population Data Services Agency. We analyzed the annual prevalence by dividing the number of KJR survivors by the population aged 40 or older. The revision burden factor (RBF) was determined by dividing the annual number of revisions by the number of primary and revision KJRs in the population. Proportions of bilateral implants and patients with older KJRs performed 10 or more years earlier were identified.ResultsKJR prevalence in Finland increased by 298% between 2000 and 2020, reaching 4.0% in 2020. The proportion of patients with bilateral KJRs and those with older KJRs had increased to 37% and 34%, respectively, by 2020. The annual RBF decreased statistically significantly from 1.9% to 0.7% between 1996 and 2020 (proportion ratio, PR 0.37 [95% CI 0.33–0.42]) and was higher among males (PR 1.23 [CI 1.20–1.26]).InterpretationAlthough the recent rapid increase in KJRs is abating and the RBF is diminishing, it is important to take the continuing increase in the prevalence of KJRs into account when assessing hospitals’ future resources.

Low incidence of clinically relevant bleeding complications after fast-track arthroplasty: a register study of 8,511 arthroplasties.

Background and purposeFast-track total joint replacement (TJR) has become increasingly common. Routine thromboprophylaxis for pulmonary embolism and deep venous thrombosis prevention lasts from 2 to 5 weeks. This retrospective registry study focused on clinically relevant bleeding complications 90 days after fast-track primary TJR.Patients and methodsAll primary fast-track total hip (THA) and knee arthroplasties (TKA) performed between 2015 and 2016 were extracted from the Finnish Arthroplasty Register and Finnish Hospital Discharge Register. Type of arthroplasty and indication for the operation were combined with diagnoses of clinically relevant bleeding complications within 90 days of surgery. The incidence of these bleedings was the primary outcome measure.ResultsOf the total of 8,511 patients (mean age 67 years (SD 10); 60% female), 45% underwent unilateral THA, 52% unilateral TKA, and 3% bilateral TKA. The incidence of clinically relevant bleeding complications within 90 days was 1% (95% CI 0.8–1.3). No difference was observed in bleeding incidence between the groups. The 87 bleedings comprised 57 operative site bleedings, 17 gastrointestinal bleedings, 6 intracranial non-traumatic bleedings, 5 bleedings from the nose or another undetermined site, and 2 intraocular bleedings. 1 death due to intracranial bleeding was recorded, and hence clinically relevant bleeding-specific 90-day mortality was 0.01%.InterpretationThe incidence of clinically relevant bleeding complications was low. However, they cause patient discomfort, increase the use of healthcare services, and can be life-threatening and even fatal.

Risk of total knee replacement after proximal tibia fracture: a register-based study of 7,841 patients.

Background and purposePost-traumatic knee osteoarthritis following proximal tibia fracture (PTF) is a common complication that may lead to total knee replacement as secondary treatment (TKRS). We determined the risk of TKRS following PTF, whether treated nonoperatively or operatively, and compared the results with a 38-fold control group without prior PTF.Patients and methodsWe identified all patients over 18 years of age in Finland with PTF treated during the period 2009–2018 from the Finnish Hospital Discharge Register (FHDR) and Finnish Arthroplasty Register (FAR). Age, sex, treatment method, follow-up time, and possible TKRS were recorded.Results7,701 patients were treated for PTF during the period 2009–2018. Over the 5.1-year (SD 3.1) follow-up, TKRS was performed in 340 (4.3%) patients with a prior PTF after a mean of 2.1 (SD 2.0) years post-fracture. TKRS was needed in 138 (3.7%, HR 1.8) patients in the nonoperatively treated group and in 202 (5.0%, HR 3.2) patients in the operatively treated group. Operative treatment, female sex, and high age were identified as risk factors for TKRS. The incidence of TKRS was highest during the first 2 years after fracture and remained elevated throughout the follow-up.InterpretationPatients with a prior PTF had a 1.8- to 3.2-fold higher risk of TKRS compared with controls during the first 5 years post-fracture. Risk of TKRS was associated with an operatively treated PTF, female sex, and high age. The patients in the operative group likely sustained more complex fractures, while female sex and age may be explained by more osteoporotic bone quality.

Risk factors for prosthetic joint infections following total hip arthroplasty based on 33,337 hips in the Finnish Arthroplasty Register from 2014 to 2018

Background and purpose — Periprosthetic joint infection (PJI) is a devastating complication and more information on risk factors for PJI is required to find measures to prevent infections. Therefore, we assessed risk factors for PJI after primary total hip arthroplasty (THA) in a large patient cohort. Patients and methods — We analyzed 33,337 primary THAs performed between May 2014 and January 2018 based on the Finnish Arthroplasty Register (FAR). Cox proportional hazards regression was used to estimate hazard ratios with 95% confidence intervals (CI) for first PJI revision operation using 25 potential patient- and surgical-related risk factors as covariates. Results — 350 primary THAs were revised for the first time due to PJI during the study period. The hazard ratios for PJI revision in multivariable analysis were 2.0 (CI 1.3–3.2) for ASA class II and 3.2 (2.0–5.1) for ASA class III–IV compared with ASA class I, 1.4 (1.1–1.7) for bleeding > 500 mL compared with < 500 mL, 0.4 (0.2–0.7) for ceramic-on-ceramic bearing couple compared with metal-on-polyethylene and for the first 3 postoperative weeks, 3.0 (1.6–5.6) for operation time of > 120 minutes compared with 45–59 minutes, and 2.6 (1.4–4.9) for simultaneous bilateral operation. In the univariable analysis, hazard ratios for PJI revision were 2.3 (1.7–3.3) for BMI of 31–35 and 5.0 (3.5–7.1) for BMI of > 35 compared with patients with BMI of 21–25. Interpretation — We found several modifiable risk factors associated with increased PJI revision risk after THA to which special attention should be paid preoperatively. In particular, high BMI may be an even more prominent risk factor for PJI than previously assessed.

Implant survival of 662 dual-mobility cups and 727 constrained liners in primary THA: small femoral head size increases the cumulative incidence of revision

Background and purpose — In total hip arthroplasty (THA), the risk for dislocation can be reduced using either dual-mobility cups (DMCs) or constrained liners (CLs). There are few studies comparing these concepts in primary THA. Therefore, we compared the cumulative incidence of revision in primary THA patients treated with DMC or CL with varying head sizes with conventional THA patients as reference group. Patients and methods — We performed a cohort study based on the Finnish arthroplasty register, comparing DMCs and CLs operated over the period 2000–2017. DMCs were divided into 2 groups based on the implant design: “DMC Trident” group (n = 399) and “DMC Others” group (n = 263). CLs were divided based on the femoral head size: “CL 36 mm” group (n = 425) and “CL < 36 mm” group (n = 302). All conventional primary THAs operated on in 2000–2017 with 28–36 mm femoral head were included as control group (“Conventional THA” group, n = 102,276). Implant survival was calculated by the corresponding cumulative incidence function with revision as the endpoint and death as competing event. Also, the prevalence of different reasons for revision was compared. Results — The 6-year cumulative incidence function estimates for the first revision were 6.9% (95% CI 4.0–9.7) for DMC Trident, 5.0% (CI 1.5–8.5) for DMC Others, 13% (CI 9.3–17) for CL < 36 mm, 6.3% (3.7–8.9) for CL 36 mm, and 4.7% (CI 4.5–4.8) for control group (conventional THA). The prevalence of dislocation revision was high (5.0%, CI 2.9–8.2) in the CL < 36 mm group compared with other groups. Interpretation — The DMC and CL 36 mm groups had promising mid-term survival rates, comparable to those of primary conventional THA group. The revision rate of CLs with < 36 mm head was high, mostly due to high prevalence of dislocation revisions. Therefore, CLs with 36 mm femoral head should be preferred over smaller ones.

Physical capability after total joint arthroplasty: long-term population-based follow-up study of 6,462 women

Background and purpose — There is lack of knowledge concerning patient-reported long-time outcome after arthroplasty. Therefore, we investigated patient self-reported physical capabilities (PC) and subjective well-being (SW) up to 20 years after total hip (THA) or knee (TKA) arthroplasty. Subjects and methods — The self-reports from postal questionnaires for study checkpoints (baseline, 10-year follow-up, 20-year follow-up) were provided by the Kuopio OSTPRE study including only women aged 52–62 years (n = 6,462). The Finnish Arthroplasty Register and Care Register for Health Care provided data on arthroplasties in the OSTPRE population. The results of women with THA/TKA were compared with women without arthroplasty (control group). Results — In subjects with THA performed before the 10-year follow-up, the proportion of good PC was initially decreased by 0.6 percentage points (pp) at the 10-year follow-up and later by 19 pp at the 20-year follow-up. After TKA, the proportion of subjects with good PC decreased by 4.1 pp (10–year follow-up) and 27 pp (20-year follow-up), respectively. The proportion of controls reporting good PC decreased by 1.4 pp at the 10-year follow-up and 14 pp at the 20-year follow-up compared with the baseline. After THA, the proportion of subjects with good SW stayed on the same level at 10-year follow-up and decreased by 2.3 pp at 20-year follow-up. After TKA, the proportion of good SW increased by 9.0 pp (10-year follow-up) and decreased by 14 pp (20-year follow-up). The proportion of controls reporting good SW increased by 4.0 pp (10-year follow-up) and decreased by 8.8 pp (20-year follow-up). Interpretation — THA and TKA maintain PC and SW. The overall PC and SW are lower in women with arthroplasty, in comparison with controls without arthroplasty. THA seems to outperform TKA in maintaining PC.

Implant survival of 2,723 vitamin E-infused highly crosslinked polyethylene liners in total hip arthroplasty: data from the Finnish Arthroplasty Register

Background and purpose — The use of crosslinked polyethylene in total hip arthroplasty (THA) has decreased wear remarkably. It has been suggested that the antioxidative effects of vitamin E may enhance the wear properties of polyethylene even further. This study evaluates revision rates between vitamin E-infused polyethylene liners (E1 and E-poly, ZimmerBiomet, Warsaw, IN, USA) versus moderately crosslinked polyethylene (ModXLPE) liners from the same manufacturer used in primary THA. Patients and methods — We conducted a study based on data from the Finnish Arthroplasty Register. The study group consisted of 2,723 THAs with a vitamin E-infused liner and a reference group of 2,707 THAs with a moderately crosslinked polyethylene liner. Survivorship, revision risk, and re-revision causes were compared between groups. Results — The 7-year survival of the vitamin E-infused polyethylene liner group and of the reference group with revision for any reason as the endpoint was comparable (94% [95% CI 92.9–94.9] and 93% [CI 91.9–93.9], respectively). The adjusted hazard ratio (HR) for any revision was similar between the groups (0.7 [CI 0.4–1.1]). When revision for aseptic loosening was studied as the endpoint, the survival for the study group was 99% (CI 98.6–99.4) and for the reference group 99% (CI 98.7–99.5), and the risk of revision was comparable between the study groups (HR 1.3 [CI 0.7–2.5]). Interpretation — After an observation period of 7 years vitamin E-infused liners shows results equal to results obtained with crosslinked polyethylene liners.

Preoperative Risk Prediction Models for Short-Term Revision and Death After Total Hip Arthroplasty: Data from the Finnish Arthroplasty Register.

Background:Because of the increasing number of total hip arthroplasties (THAs), even a small proportion of complications after the operation can lead to substantial individual difficulties and health-care costs. The aim of this study was to develop simple-to-use risk prediction models to assess the risk of the most common reasons for implant failure to facilitate clinical decision-making and to ensure long-term survival of primary THAs.Methods:We analyzed patient and surgical data reported to the Finnish Arthroplasty Register (FAR) on 25,919 primary THAs performed in Finland between May 2014 and January 2018. For the most frequent adverse outcomes after primary THA, we developed multivariable Lasso regression models based on the data of the randomly selected training cohort (two-thirds of the data). The performances of all models were validated using the remaining, independent test set consisting of 8,640 primary THAs (one-third of the data) not used for building the models.Results:The most common outcomes within 6 months after the primary THA were revision operations due to periprosthetic joint infection (1.1%), dislocation (0.7%), or periprosthetic fracture (0.5%), and death (0.7%). For each of these outcomes, Lasso regression identified subsets of variables required for accurate risk predictions. The highest discrimination performance, in terms of area under the receiver operating characteristic curve (AUROC), was observed for death (0.84), whereas the performance was lower for revisions due to periprosthetic joint infection (0.68), dislocation (0.64), or periprosthetic fracture (0.65).Conclusions:Based on the small number of preoperative characteristics of the patient and modifiable surgical parameters, the developed risk prediction models can be easily used to assess the risk of revision or death. All developed models hold the potential to aid clinical decision-making, ultimately leading to improved clinical outcomes.Level of Evidence:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Good mid-term outcome of the rotating hinge knee in primary total knee arthroplasty – Results of a single center cohort of 106 knees with a median follow-up of 6.3 years

BackgroundThe prognosis of complex primary total knee arthroplasty (TKA) with severe deformity and ligament deficiency is not clear. There is a paucity of evidence in the current literature on treatment outcomes of the rotating hinge knee implants in primary TKA. The aim of this study was to determine the mid-term clinical, radiographic, and health-related quality of life (HRQoL) outcomes in patients who had undergone complex primary TKA using single hinged knee replacement. MethodsIn total, 106 complex primary TKAs (101 patients) were performed using the single rotating hinged knee (RHK) implant design at our institution between January 2004 and December 2013. We conducted a retrospective analysis of prospectively collected outcome data of these patients, obtaining also information on all possible revision surgeries from the Finnish Arthroplasty Register, and conducted a prospective follow-up study of all living patients. ResultsThe 10-year Kaplan-Meier survival rate of the RHK knees was 91.6% (95% CI 86.0% to 97.2%) with revision for any reason as the endpoint. Overall, eight knees (7.5 %) underwent revision surgery during the follow-up. None of the unrevised RHK knees were radiographically loose. The majority of patients evinced good clinical outcome and quality of life as measured with patient reported outcome measures. ConclusionThe hinge knee replacement which was assessed current study can be regarded as a suitable option in complex primary TKA, provided adequate attention is paid to the correct indications and patient selection.

Posterior approach, fracture diagnosis, and american society of anesthesiology class iii-iv are associated with increased risk of revision for dislocation after total hip arthroplasty: An analysis of 33,337 operations from the finnish arthroplasty register.

Background and objective:Dislocation is one of the most common reasons for revision surgery after primary total hip arthroplasty. Both patient related and surgical factors may influence the risk of dislocation. In this study, we evaluated risk factors for dislocation revision after total hip arthroplasty based on revised data contents of the Finnish Arthroplasty Register.Methods:We analyzed 33,337 primary total hip arthroplasties performed between May 2014 and January 2018 in Finland. Cox proportional hazards regression was used to estimate hazard ratios with 95% confidence intervals for first dislocation revision using 18 potential risk factors as covariates, such as age, sex, diagnosis, hospital volume, surgical approach, head size, body mass index, American Society of Anesthesiology class, and fixation method.Results:During the study period, there were 264 first-time revisions for dislocation after primary total hip arthroplasty. The hazard ratio for dislocation revision was 3.1 (confidence interval 1.7–5.5) for posterior compared to anterolateral approach, 3.0 (confidence interval 1.9–4.7) for total hip arthroplasties performed for femoral neck fracture compared to total hip arthroplasties performed for osteoarthritis, 2.0 (confidence interval 1.0–3.9) for American Society of Anesthesiology class III–IV compared to American Society of Anesthesiology class I, and 0.5 (0.4–0.7) for 36-mm femoral head size compared to 32-mm head size.Conclusions:Special attention should be paid to patients with fracture diagnoses and American Society of Anesthesiology class III–IV. Anterolateral approach and 36-mm femoral heads decrease dislocation revision risk and should be considered for high-risk patients.

Implant Survival of 6,080 Tritanium Cups in Primary Total Hip Arthroplasty: Data from the Finnish Arthroplasty Register from 2009 to 2017.

To enhance osseointegration in total hip arthroplasty (THA), ultraporous or highly porous-coated cups were introduced. Implant survival data on these new devices have been scarce. The aim of our study was to assess the survivorship of ultraporous Tritanium cups (Stryker) in a population-based register study. In this study, we collected data on 6,080 primary THAs using a Tritanium cup and 25,670 THAs using a conventional cup (control group) from the Finnish Arthroplasty Register; these procedures were performed from January 1, 2009, to December 31, 2017. We calculated the Kaplan-Meier survival estimates with 95% confidence intervals (CIs). The end point was revision for any reason or for aseptic loosening of the cup. The revision risks were assessed with use of the Cox multiple regression model. The variables assessed in the Cox model were femoral head size, age group, involved side, operation year, sex, diagnosis, and fixation of the stem. The proportional hazards assumption of the Cox model was not fulfilled, so the follow-up time was divided into 3 time periods: 0 to 2 years, >2 to 4 years, and >4 years. When comparing the 2 groups with regard to revision for any reason, the 5-year Kaplan-Meier survivorship of the Tritanium group (94.7% [95% CI, 94.0% to 95.4%]) was inferior to that of the control group (96.0% [95% CI, 95.7% to 96.3%]). In the Cox regression analysis of the 2 groups for the time period of >4 years, the Tritanium group had an increased risk of revision for any reason compared with the control group (hazard ratio [HR], 3.12 [95% CI, 1.82 to 5.35]; p < 0.001). With regard to revision for aseptic loosening of the cup, the Tritanium group had an increased risk of revision compared with the control group for both 0 to 2 years (HR, 3.80 [95% CI, 1.76 to 8.24]; p < 0.001) and >2 to 4 years (HR, 11.2 [95% CI, 3.28 to 38.0]; p < 0.001). There was no advantage to using the ultraporous-coated Tritanium cup for primary THA compared with conventional uncemented cups. However, wide CIs for some HR estimates may point to a lack of precision. Therefore, further research on subject is needed. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Implant Survival of Constrained Acetabular Device in Primary Total Hip Arthroplasty Based on Data From the Finnish Arthroplasty Register

BackgroundConstrained acetabular devices were developed to prevent dislocations after total hip arthroplasty (THA). However, the data on their success have been contradictory. In this study, we aimed to assess implant survival of the constrained acetabular device in primary THA based on the Finnish Arthroplasty Register data. MethodsA total of 373 primary THAs with constrained acetabular devices inserted from 2006 to 2017 were included. A reference group was formed on a 1:3 basis and matched for age, sex, and diagnosis, consisting of 1118 conventional THAs. Implant survival estimates using death as a competing risk were assessed with revision for any reason and for any aseptic reason as the endpoints. The Cox multiple regression models were adjusted for age, sex, and diagnosis. The mean follow-up time was 3.3 (0-12.4) years for the constrained device group and 3.8 (0-12.0) years for the reference group. ResultsOverall, there were 21 revisions in the constrained device group and 49 in the reference group. The 8-year survivorship for any reason was 94% (confidence interval [CI]: 91-96) for the constrained device group and 93% (CI: 89-97) for the reference group. With revision for any aseptic reason as the endpoint, the 8-year survivorships were 97% (CI: 95-99) and 94% (CI: 90-98), respectively. During the first 1.5 years, the constrained acetabular device group had a similar revision risk (hazard ratio: 1.09 [CI: 0.57-2.07], P = .8) to that of the reference group. ConclusionThe constrained acetabular device had good survival in primary THA, and our results support its continued use even in high-risk patients.

No effect of delivery on total hip replacement survival: a nationwide register study in Finland

Background and purpose — Previous small studies have suggested that delivery does not adversely affect the survivorship of total hip replacement (THR). We investigated whether delivery after primary THR affects hip implant survivorship in a large population-based study samplePatients and methods — In this register-based nationwide cohort study, all women aged 15–45 who underwent primary THR in Finland from 1987 to 2007 were included from the Finnish Arthroplasty Register. Data on deliveries were obtained from the medical birth register. After primary THR, 111 women (133 THRs) delivered and formed the delivery group. In the reference group, 1,878 women (2,343 THRs) had no deliveries. We used Kaplan–Meier analysis with 95% confidence intervals (CI) to study implant survivorship at 6 and 13 years, and Cox multiple regression to assess survival and hazard ratios (HRs), with revision for any reason as an endpoint with adjustment for age, rheumatoid arthritis, and stem and cup fixation.Results — 51 (38%) revisions were recorded in the delivery group and 645 (28%) revisions in the reference group. The 6-year implant survivorship was 91% (CI 85–96) in the delivery group and 88% (CI 87–90) in the reference group. The 13-year survival rates were 50% (CI 39–62) and 61% (CI 59–64). The adjusted HR for revision after delivery was 0.7 (CI 0.4–1.2) in ≤ 6.8 years’ follow-up and 1.1 (CI 0.8–1.6) in > 6.8 years’ follow-up.Interpretation — Based on the findings in this nationwide study of hip replacement in fertile-aged women, delivery does not seem to decrease THR implant survivorship; women should not be afraid of or avoid becoming pregnant after THR.

Survival of 11,390 Continuum cups in primary total hip arthroplasty based on data from the Finnish Arthroplasty Register

Background and purpose — The use of trabecular metal (TM) cups for primary total hip arthroplasty (THA) is increasing. Some recent data suggest that the use of TM in primary THA might be associated with an increased risk of revision. We compared implant survival of Continuum acetabular cups with other commonly used uncemented cups.Patients and methods — Data on 11,390 primary THAs with the Continuum cup and 30,372 THAs with other uncemented cups (reference group) were collected from the Finnish Arthroplasty Register. Kaplan–Meier survival estimates were calculated; the endpoint was revision for any reason, for infection, or for dislocation. Revision risks were assessed with adjusted Cox multiple regression models. A subgroup analysis on the use of neutral or elevated liners in the Continuum group was made.Results — The 7-year survivorship of the Continuum group was 94.6% (95% CI 94.0–95.2) versus 95.6% (CI 95.3–95.8) in the reference group for revision for any reason. The risk for revision was higher in the Continuum group than in the reference group both for revision for any reason (HR 1.3 [CI 1.2–1.5)]) and for revision for dislocation (HR 1.9 [CI 1.5–2.3]). There was no difference in the rates of revision because of infection (HR 0.99 [CI 0.78–1.3]). Use of a neutral liner increased the risk for revision due to dislocation in comparison with the use of an elevated rim liner in the Continuum group (HR 1.7 [CI 1.2–2.5]).Interpretation — THA with Continuum cups is associated with an increased risk of revision compared with other uncemented cups, mainly due to revisions because of dislocation. Our results support the use of an elevated liner when Continuum cups are used for primary THA.

Short-term survival of cementless Oxford unicondylar knee arthroplasty based on the Finnish Arthroplasty Register

BackgroundCementless unicondylar knee arthroplasty (UKA) was introduced to secure long-term fixation and reduce the risk of revision. Experience with cementless UKA fixation is limited. MethodsThe short-term survival (up to five years) of cementless Oxford UKA was assessed using data from the Finish Arthroplasty Register and was compared with that of cemented Oxford 3 UKA and total knee arthroplasty (TKA). Datawere obtained, from the Finnish Arthroplasty Register, on 1076 cementless Oxford UKAs and 2279 cemented Oxford 3 UKAs performed for primary osteoarthritis in 2005-2015. The Kaplan-Meier method, with revision for any reason as the endpoint, was used to assess the survival of these two UKA groups, and the results were compared with that of 65,563 cemented TKAs treated for primary osteoarthritis over the same period. The risk of revision of both Oxford prostheses was compared using Cox regression model, with adjustment for age and sex, with the cemented TKA group as reference. ResultsThe three-year survival was 93.7% for the cementless Oxford, 92.2% for the cemented Oxford 3, and 97.3% for the cemented TKA. The corresponding figures at five years were 92.3%, 88.9%, and 96.6%, respectively. The revision rate for both the cementless Oxford and the cemented Oxford 3 was significantly increased when compared with the cemented TKA (P < 0.001). ConclusionsThe survival of the cementless Oxford method was higher than that of the cemented Oxford 3 in the short term. The overall survival of Oxford UKA was poor in comparison with contemporary TKAs.