A prospective study on cancer risk after total hip replacements for 41,402 patients linked to the Cancer registry of Norway.

Background: Concerns have been raised that implants used in total hip replacements (THR) could lead to increased cancer risk. Several different materials, metals and fixation techniques are used in joint prostheses and different types of articulation can cause an increased invasion of particles or ions into the human body.

Methods: Patients with THR registered in the Norwegian Arthroplasty Register during 1987-2009 were linked to the Cancer registry of Norway.

Dual Mobility Cups: Effect on Risk of Revision of Primary Total Hip Arthroplasty Due to Osteoarthritis: A Matched Population-Based Study Using the Nordic Arthroplasty Register Association Database.

Background: The dual mobility acetabular cup (DMC) was designed to reduce prosthetic instability and has gained popularity for both primary and revision total hip arthroplasty (THA). We compared the risk of revision of primary THA for primary osteoarthritis between patients treated with a DMC and those who received a metal-on-polyethylene (MoP) or ceramic-on-polyethylene (CoP) bearing.

Methods: A search of the Nordic Arthroplasty Register Association (NARA) database identified THAs performed with a DMC during 1995 to 2013.

Patient and surgical factors affecting procedure duration and revision risk due to deep infection in primary total knee arthroplasty.

Background: The aim of this study was to assess which patient and procedure factors affected both the risk of infection as well as procedure duration. Additionally, to assess if procedure duration affected the revision risk due to deep infection in total knee arthroplasty (TKA) patients and in a subgroup of low-risk patients.

Methods: 28,262 primary TKA with 311 revisions due to deep infection were included from the Norwegian Arthroplasty Register (NAR) and analysed from primary surgery from 2005 until 31st December 2015 with a 1 and 4 year follow up.

Hospital volume and the risk of revision in Oxford unicompartmental knee arthroplasty in the Nordic countries -an observational study of 14,496 cases.

Background: High procedure volume and dedication to unicompartmental knee arthroplasty (UKA) has been suggested to improve revision rates. This study aimed to quantify the annual hospital volume effect on revision risk in Oxfordu nicompartmental knee arthroplasty in the Nordic countries.

Methods: 14,496 cases of cemented medial Oxford III UKA were identified in 126 hospitals in the four countries included in the Nordic Arthroplasty Register Association (NARA) database from 2000 to 2012.

Improved outcome after hip fracture surgery in Norway.

Background and purpose - The operative treatment of hip fractures in Norway has changed considerably during the last decade. We used data in the Norwegian Hip Fracture Register to investigate possible effects of these changes on reoperations and 1-year mortality. Patients and methods - 72,741 femoral neck (FFN) fractures and trochanteric fractures in patients 60 years or older were analyzed.

Implant Survival After Minimally Invasive Anterior or Anterolateral Vs. Conventional Posterior or Direct Lateral Approach: An Analysis of 21,860 Total Hip Arthroplasties from the Norwegian Arthroplasty Register (2008 to 2013).

Background: Since 2008, there has been an increase in the use of minimally invasive surgery (MIS) through an anterior or anterolateral approach for total hip arthroplasty (THA) in Norway. We compared the MIS approaches with the conventional posterior and direct lateral approaches in terms of revision rates and risk of revision.

Methods: On the basis of data in the Norwegian Arthroplasty Register, 21,860 THAs with an uncemented stem, performed between 2008 and 2013, were identified and included in the cohort.

Reverse hybrid total hip arthroplasty.

Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty Register Association (NARA) has already published 2 papers describing results of reverse hybrid THAs in different age groups.

Bone cement product and failure in total knee arthroplasty.

Background and purpose - The bone cement market for total knee arthroplasty (TKA) in Norway has been dominated by a few products and distributors. Palacos with gentamicin had a market share exceeding 90% before 2005, but it was then withdrawn from the market and replaced by new slightly altered products. We have compared the survival of TKAs fixated with Palacos with gentamicin with the survival of TKAs fixated with the bone cements that took over the market.

Posterior approach compared to direct lateral approach resulted in better patient-reported outcome after hemiarthroplasty for femoral neck fracture.

Background and purpose - Hemiarthroplasty (HA) is the most common treatment for displaced femoral neck fractures in many countries. In Norway, there has been a tradition of using the direct lateral surgical approach, but worldwide a posterior approach is more often used. Based on data from the Norwegian Hip Fracture Register, we compared the results of HA operated through the posterior and direct lateral approaches regarding patient-reported outcome measures (PROMs) and reoperation rate.

A cemented cup with acetabular impaction bone grafting is more cost-effective than an uncemented cup in patients under 50 years.

Purpose: Acetabular deficiencies in young patients can be restored in several ways during total hip arthroplasty. Currently, cementless cups are most frequently used. Impaction bone grafting of acetabular defects is a more biological approach, but is it cost-effective in young patients on the long term?

Methods: We designed a decision model for a cost-utility analysis of a cemented cup with acetabular impaction bone grafting versus an uncemented cup, in terms of cost per quality-adjusted life year (QALY) for the young adult with acetabular bone deficiency, in need for a primary total hip arthroplasty.

Better survival of hybrid total knee arthroplasty compared to cemented arthroplasty.

Background And Purpose: There have been few comparative studies on total knee replacement (TKR) with cemented tibia and uncemented femur (hybrid TKR). Previous studies have not shown any difference in revision rate between cemented and hybrid fixation, but these studies had few hybrid prostheses. We have evaluated the outcome of hybrid TKR based on data from the Norwegian Arthroplasty Register (NAR).

The risk of revision in total knee arthroplasty is not affected by previous high tibial osteotomy.

Background And Purpose: Previous studies have found different outcomes after revision of knee arthroplasties performed after high tibial osteotomy (HTO). We evaluated the risk of revision of total knee arthroplasty with or without previous HTO in a large registry material.

Patients And Methods: 31,077 primary TKAs were compared with 1,399 TKAs after HTO, using Kaplan-Meier 10-year survival percentages and adjusted Cox regression analysis.

Increased risk of revision of cementless stemmed total hip arthroplasty with metal-on-metal bearings.

Background And Purpose: Data from the national joint registries in Australia and England and Wales have revealed inferior medium-term survivorship for metal-on-metal (MoM) total hip arthroplasty (THA) than for metal-on-polyethylene (MoP) THA. Based on data from the Nordic Arthroplasty Register Association (NARA), we compared the revision risk of cementless stemmed THA with MoM and MoP bearings and we also compared MoM THA to each other.

Patients And Methods: We identified 32,678 patients who were operated from 2002 through 2010 with cementless stemmed THA with either MoM bearings (11,567 patients, 35%) or MoP bearings (21,111 patients, 65%).

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.

Periprosthetic femoral fracture within two years after total hip replacement: analysis of 437,629 operations in the nordic arthroplasty register association database.

Background: We used the Nordic Arthroplasty Register Association database to evaluate whether age, sex, preoperative diagnosis, fixation, and implant design influence the risk of revision arthroplasty due to periprosthetic fracture within two years from operation of a primary total hip replacement.

Methods: Included in the study were 325,730 cemented femoral stems and 111,899 uncemented femoral stems inserted from 1995 to 2009. Seven frequently used stems (two cemented stems [Exeter and Lubinus SP II] and five uncemented stems [Bi-Metric, Corail, CLS Spotorno, ABG I, and ABG II]) were specifically studied.

Worse patient-reported outcome after lateral approach than after anterior and posterolateral approach in primary hip arthroplasty. A cross-sectional questionnaire study of 1,476 patients 1-3 years after surgery.

Background: The surgical approach in total hip arthroplasty (THA) is often based on surgeon preference and local traditions. The anterior muscle-sparing approach has recently gained popularity in Europe. We tested the hypothesis that patient satisfaction, pain, function, and health-related quality of life (HRQoL) after THA is not related to the surgical approach.

Higher revision risk for unicompartmental knee arthroplasty in low-volume hospitals.

Background And Purpose: Some studies have found high complication rates and others have found low complication rates after unicompartmental knee arthroplasty (UKA). We evaluated whether hospital procedure volume influences the risk of revision using data from the Norwegian Arthroplasty Register (NAR).

Materials And Methods: 5,791 UKAs have been registered in the Norwegian Arthroplasty Register.

Countrywise results of total hip replacement. An analysis of 438,733 hips based on the Nordic Arthroplasty Register Association database.

Background And Purpose: An earlier Nordic Arthroplasty Register Association (NARA) report on 280,201 total hip replacements (THRs) based on data from 1995-2006, from Sweden, Norway, and Denmark, was published in 2009. The present study assessed THR survival according to country, based on the NARA database with the Finnish data included.

Material And Methods: 438,733 THRs performed during the period 1995-2011 in Sweden, Denmark, Norway, and Finland were included.

Increased risk of revision in patients with non-traumatic femoral head necrosis.

Background And Purpose: Previous studies of patients who have undergone total hip arthroplasty (THA) due to femoral head necrosis (FHN) have shown an increased risk of revision compared to cases with primary osteoarthritis (POA), but recent studies have suggested that this procedure is not associated with poor outcome. We compared the risk of revision after operation with THA due to FHN or POA in the Nordic Arthroplasty Register Association (NARA) database including Denmark, Finland, Norway, and Sweden.

Patients And Methods: 427,806 THAs performed between 1995 and 2011 were included.

Hip replacement surgery in patients with ankylosing spondylitis.

Objectives: Although TNF-α inhibitors' striking effect on clinical symptoms have revolutionised the treatment of ankylosing spondylitis (AS), no certain influence on the development of spinal ankylosis and joint destruction has been documented. We wished to investigate whether improved treatment has affected the use of hip arthroplasty surgery.

Methods: Using the Norwegian Arthroplasty Register, we selected hip prosthesis procedures performed in patients with AS in 1988-2010 (n=534), and compared the trend in the number of procedures being performed annually in 1988-2002 versus 2003-2010.

Complications after intramedullary nailing of femoral fractures in a low-income country.

Background: Some surgeons believe that internal fixation of fractures carries too high a risk of infection in low-income countries (LICs) to merit its use there. However, there have been too few studies from LICs with sufficient follow-up to support this belief. We first wanted to determine whether complete follow-up could be achieved in an LIC, and secondly, we wanted to find the true microbial infection rate at our hospital and to examine the influence of HIV infection and lack of follow-up on outcomes.

Influence of hospital volume on revision rate after total knee arthroplasty with cement.

Background: The number of total knee replacements has substantially increased worldwide over the past ten years. Several studies have indicated a correlation between high hospital procedure volume and decreased morbidity and mortality following total knee arthroplasty. The purpose of the present study was to evaluate whether there is a correlation between procedure volume and the risk of revision following total knee arthroplasty with use of hospital volume data from the Norwegian Arthroplasty Register.

TRIGEN INTERTAN intramedullary nail versus sliding hip screw: a prospective, randomized multicenter study on pain, function, and complications in 684 patients with an intertrochanteric or subtrochanteric fracture and one year of follow-up.

Background: Both intramedullary nails and sliding hip screws are used with good results in the treatment of intertrochanteric and subtrochanteric fractures. The aim of our study was to assess whether use of the TRIGEN INTERTAN nail, as compared with a sliding hip screw, resulted in less postoperative pain, improved functional mobility, and reduced surgical complication rates for patients with an intertrochanteric or subtrochanteric fracture.

Methods: In a prospective, randomized multicenter study, 684 elderly patients were treated with the INTERTAN nail or with a sliding hip screw with or without a trochanteric stabilizing plate.