In 1975, Sweden started registering primary knee replacement surgeries based on the personal identity number. Individual-based registrations of primary total hip replacements started in 1992 and for hemiarthroplasties the registration started in 2006. The completeness of these registrations is estimated at 98% during the last 10-year period. The long history and high completeness allow for accurate calculations of population-based prevalence of joint replacement and trends over time.

We used all data on primary joint replacements available in the Swedish Arthroplasty Register. The prevalence was calculated using number of alive patients with 1) at least one joint replacement 2) at least one hip replacement 3) at least one knee replacement at the end of each year from 2010 – 2021. Publicly available population numbers were retrieved from Statistics Sweden. We calculated total prevalence and prevalence per age in years.

By the end of 2021, 3.2% of the Swedish population had at least one hip or knee replacement. This was an increase from 2.5% in 2010. Among 80-year-old, the prevalence was 17.5% for any joint replacement. For both hip and knee replacement and all ages, the prevalence was higher for women. For knee replacement, the 2021 prevalence peaked at the age of 89 (9,4%) while the prevalence continuously increased with age for hip replacements.

A considerable proportion of the Swedish elderly population is living with at least one hip or knee replacement. The prevalence has increased during the last 12-year period for both hips and knees. An increasing prevalence may also affect the incidence of fractures and infections. Knowledge about the prevalence is fundamental for planning future demand for primary and revision hip and knee replacement.

Increased collection of patient-reported outcome measures (PROM) in registries enables international comparison of patient-centered outcomes after knee and hip replacement. We aimed to investigate 1) variations in PROM improvement, 2) the possible confounding factor of BMI, and 3) differences in comorbidity distributions between registries.

Registries affiliated with the International Society of Arthroplasty Registries (ISAR) or OECD membership countries were invited to report aggregate EQ-5D, OKS, OHS, HOOS-PS and KOOS-PS values. Eligible patients underwent primary total, unilateral knee or hip replacement for osteoarthritis within three years and had completed PROMs preoperatively and either 6 or 12 months postoperatively, excluding patients with subsequent revisions. For each PROM cohort, Chi-square tests were performed for BMI distributions across registries and 12 predefined PROM strata (male/female, age 20-64/65-74/>75, high or low preoperative PROM scores). Comorbidity distributions were reported for available comorbidity indexes.

Thirteen registries from 9 countries contributed data, n~130000 knee (range 140 to 79848) and n~113000 hip (range 137 to 85281). Mean EQ-5D index values (10 registries) ranged from 0.53 to 0.71 (knee) and 0.50 to 0.70 (hips) preoperatively and 0.78 to 0.85 (knee) and 0.83 to 0.87 (hip) postoperatively. Mean OKS (6 registries) ranged from 19.3 to 23.6 preoperatively and 36.2 to 41.2 postoperatively. Mean OHS (7 registries) ranged from 18.0 to 23.2 preoperatively and 39.8 to 44.2 postoperatively. Four registries reported KOOS-PS and three reported HOOS-PS. Proportions of patients with BMI >30 ranged from 35 to 62% (10 knee registries) and 16 to 43% (11 hip registries). For both knee and hip registries, distributions of patients across six BMI categories differed significantly among registries (p30 were for patients in the youngest age groups (20 to 64 and 65 to 74 years) with the lowest baseline scores. Additionally, females with lowest preoperative PROM scores had highest BMI. These findings were echoed for the OHS and OKS cohorts. Proportions of patients with ASA scores ≥3 ranged from 7 to 42% (9 knee registries) and 6 to 35% (8 hip registries).

PROM-score improvement varies between international registries, which may be partially explained by differences in age, sex and preoperative scores. BMI and comorbidity may be relevant to adjust for.

Background

Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a severe complication in terms of disability, morbidity, and cost. We performed a study to investigate whether early PJI (within 90 days of primary TKA) is associated with increased mortality. Secondary aims were to compare mortality rates over time and between surgical treatment methods.

Aim

Strenuous efforts to minimize postoperative infection rates have been made, including the Swedish nation-wide initiative Prosthesis Related Infections Shall be Stopped (PRISS). The aim of this study was to calculate the incidence rate of periprosthetic joint infections (PJI) following primary total knee arthroplasty (TKA) before and after PRISS.

Background

The modern modular implants allow surgeons to combine different combinations of components within the same brand of which some may have completely different design.

During 1999–2012 the same cemented femur component was used together with a cemented stemmed tibia baseplate and also against a cemented pegged tibia baseplate. We decided to compare the revision rate of total knee arthroplasties (TKAs) using these two tibia baseplates.

Aim

Patients reporting penicillin allergy do often receive clindamycin as systemic antibiotic prophylaxis. The effect of clindamycin has however not been compared to antibiotics with proven effect in joint arthroplasty surgery. The aim of the study was to reveal if there were differences in the rate of revision due to infection after total knee arthroplasty (TKA) depending on which antibiotic was used as systemic prophylaxis.

To reveal if patient reported knee-related pain, function, quality of life, general health and satisfaction at one year after primary total knee arthroplasty (TKA) is different between patients not being subject to revision surgery and those having had early treatment with open debridement and exchange of the tibial insert for postoperative PJI.

The Swedish Knee Arthroplasty Register was used to identify 50 patients in the region of Skane that had a primary TKA during the years 2008 – 2012 and within 6 months were revised with open debridement and exchange of the tibial insert due to suspected or verified PJI. Only patients without further revisions were included. Patient reported outcome measurements (PROM) were obtained preoperatively and 1 year postoperatively and included knee related pain, function, quality of life using the Knee injury and Osteoarthritis Outcome Score (KOOS), general health using the EQ-VAS as well as satisfaction with the surgery. The scores were compared to those reported by 3,913 patients having a TKA during the same time but not revised during the first year. Welch's t-test and the Chi2-test were used in statistical analysis.

Compared to the controls the infected patients were older (mean age 72 vs 69 years, p = 0.04) and were more morbid (ASA 3; 14/50 patients vs 14%, p = 0.02). The preoperative PROM data were similar. Complete 1 year PROM data was available for 31 of the patients. Those patients reported somewhat worse outcome one year postoperatively than the controls with statistically and clinically significant differences in general health (mean 61 vs 76, p=0.002), KOOS ADL (mean 65 vs 76, p=0.03) and knee related quality of life (mean 51 vs 63, p=0.02) with large variations on individual level. Just over half of the patients (17/29) treated for PJI were very satisfied or satisfied with the surgery compared to 79% of the controls.

Patients treated with open debridement and exchange of the tibial insert due to early PJI after primary TKA reported less beneficial postoperative outcome than those without revision surgery during the first postoperative year but with large individual variations.

We are entering a new era with governmental bodies taking an increasingly guiding role, gaining control of registries, demanding direct access with release of open public information for quality comparisons between hospitals. This review is written by physicians and scientists who have worked with the Swedish Knee Arthroplasty Register (SKAR) periodically since it began. It reviews the history of the register and describes the methods used and lessons learned.

Cite this article: Bone Joint Res 2014;3:217–22.

Introduction

In contrast to knee arthroplasty, there is no national register on high tibial osteotomy (HTO) in Sweden. The knowledge of the outcome of HTO as a treatment alternative for knee osteoarthritis (OA) is insufficient. The rate of revision to knee arthroplasty after HTO at 10 years has been reported to vary between 8 and 49%. The aim of the study was to evaluate the outcome of HTO performed in Sweden 1998–2007, expressed by rate of revision to knee arthroplasty.

Patienter och Material: 3 196 HTO (69% men) 30 years or older operated on for knee OA in Sweden 1998–2007 were identified through the in- and out-patient care registers from the Swedish National Board of Health and Welfare. Side, left/right, that was operated, diagnosis and indication for surgery were verified through surgical records. Conversions of HTO to knee arthroplasty before 2010 were identified through the Swedish Knee Arthroplasty Register (SKAR). In about 10% of the cases it was unknown what side the HTO had been performed on and thus if the arthroplasty had been on the same knee. In these cases we assumed a worst case scenario of all having been on the same side as the HTO. A 10-year survival analysis was performed using revision to an arthroplasty as the end point.

Introduction: In recent years some countries have shown increasing interest and use of unicompartmental knee arthroplasty (UKA). Several studies have reported increasing use of UKA for osteoarthritis in younger patients with low revision rates. The aim of this study was to determine the outcome of UKA by combining two national databases containing prospectively collected data.

Method: Over 50 000 UKA procedures were analyzed to determine the cumulative percentage revision (CPR). Any reason for revision was used as the end point. The analysis was stratified according to age, gender and type of prosthesis to determine outcomes in patients younger than 65 years

Result: In this study both countries showed declining use of UKA in terms of the proportion of knee replacement procedures and of absolute numbers undertaken per year. The seven year CPR of UKA in patients younger than 65 years was 16.2%, and at 10 years was 17.5%. No significant difference was found between gender, however outcome did vary depending on the type of prosthesis used.

Conclusion: This study reports the outcomes from the two largest databases of UKA. Within 10 years of UKA a substantial number of revisions were seen in patients younger than 65 years, with varying results depending on the type of prosthesis used.

The success of a high tibial osteotomy is predicted on proper patient selection, achievement and maintenance of adequate correction and avoidance of complications. It is a successful procedure when the patient’s pain is reduced or eliminated, the knee movement is preserved, and the need for a joint replacement is eliminated or postponed.

475 open wedge procedures using the hemicallotasis technique (HCO) were followed consecutively since a progressive introduction 1993. All patients were followed and compiled in a data base, 307 men, 168 women were included. The indications were arthrosis 439, sequels of fracture 12, correction 12, seqv osteotomy 7, others 5. For the arthritic knees 343 were med gr 1–3 343, med gr 4–5 35, lat arthrosis 37, prearthrosis 4. 32 patients were bilateral operated at one session.

The surgical technique is simple, using a ventral external fixator – the Orthofix T Garche. The technique is in principle extra articular. The patients were followed once/week and complications were compiled. The patient’s perspective of the HCO were evaluated for 58 patients using the KOOS questionare.

Complications as reoperation with reposition of pins 9 cases, septic arthritis 6, non-union 11, early loss of correction 5, nerve palsy 3 (all regress), interrupted treatment 3, DVT 10. For all complications including pin site infection, smoking were the single greatest preoperative risk factor (p< 0.022). 27 patients operated by HCO were converted to a joint replacement. The mean frame time was 99 + 20 days, 94/466 had a frame time > 16 weeks (smoking< 0.001). The patients self asessment were improved during treatment for the KOOS subcategories pain, function, ADL and Quality of life, but during treatment there were no improvement in sport/recreational function.

We found the HCO technique good, surgicallysimple, but there is a need for a close contact between the patient and the treatment team. This technique is probably the best when doing corrections greater than 15 degree. The largest single correction was 33 degree. The risk for septic arthritis using in a principle extra articular technique has to be considered.