Göran Garellick

The Swedish Total Hip Replacement Register

Epidemiology of Primary and Revision Total Hip Replacement Introduction he Swedish Total Hip Replacement Register was initiated in 1979. The mission of the Register is to improve the outcome of total hip replacement (THR). Information technology development has substantially facilitated the possibility of fulfilling this mission. During the past three years, almost all information exchange between the reporting units and the Register has been provided via the Internet. Feedback to and reports from the participating units are effected through a specific website (www.jru.orthop.gu.se). The importance of the Register and its effect on quality improvement over time have been well documented. The hypothesis for the project is that feedback of analyzed data stimulates the individual clinic to reflect and improve according to the principle of the good example. The clinical and socioeconomic effects of the past twenty years of Register work have been striking, and almost fifty quality registries have been started in different medical fields in Sweden during the last decade.

Future clinical and economic impact of revision total hip and knee arthroplasty

A recent analysis of historical procedure data indicated that the prevalence of primary and revision total hip and total knee arthroplasty increased steadily between 1990 and 20021. A massive demand for primary and revision surgeries is also expected in the next two decades2. Similarly, the overall incidence of deep infection also has increased substantially between 1990 and 2003 for both total hip arthroplasty and total knee arthroplasty3. In 2003, approximately 1.2% of the total hip arthroplasties performed in the United States were associated with deep infection, which was similar to the rate seen for total knee arthroplasties3. Deep infection is a catastrophic complication of both total hip and total knee arthroplasty, and it also represents a tremendous economic burden4,5. The implications for a growing incidence of infections, coupled with accelerating demand for arthroplasty, remain unexplored. Long-term survival of total hip arthroplasty and total knee arthroplasty implants has been investigated by Scandinavian arthroplasty registries6-8. However, in the United States, national hip and knee registries have not been established9,10. Medicare claims data have been used effectively in longitudinal analysis of mortality and morbidity following joint replacement11, but the feasibility of using this data as a registry substitute is unclear. Along with the projected increase in the utilization of total hip arthroplasty and total knee arthroplasty2, retrospective studies have shown increasing disparity between Medicare reimbursement and hospital charges, with higher charges for revision than for primary procedures12-14. The economic consequences of the projected demand for total hip arthroplasty and total knee arthroplasty are still unknown. The goals of our study were to (1) quantify the future number of infections at the site of arthroplasties done …

Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register.

Background and purpose Since the introduction of total hip arthroplasty (THA) in Sweden, both components have most commonly been cemented. A decade ago the frequency of uncemented fixation started to increase, and this change in practice has continued. We therefore analyzed implant survival of cemented and uncemented THA, and whether the modes of failure differ between the two methods of fixation. Patients and methods All patients registered in the Swedish Hip Arthroplasty Register between 1992 and 2007 who received either totally cemented or totally uncemented THA were identified (n = 170,413). Kaplan-Meier survival analysis with revision of any component, and for any reason, as the endpoints was performed. Cox regression models were used to calculate risk ratios (RRs) for revision for various reasons, adjusted for sex, age, and primary diagnosis. Results Revision-free 10-year survival of uncemented THA was lower than that of cemented THA (85% vs. 94%, p < 0.001). No age or diagnosis groups benefited from the use of uncemented fixation. Cox regression analysis confirmed that uncemented THA had a higher risk of revision for any reason (RR = 1.5, 95% CI: 1.4–1.6) and for aseptic loosening (RR = 1.5, CI: 1.3–1.6). Uncemented cup components had a higher risk of cup revision due to aseptic loosening (RR = 1.8, CI: 1.6–2.0), whereas uncemented stem components had a lower risk of stem revision due to aseptic loosening (RR = 0.4, CI: 0.3–0.5) when compared to cemented components. Uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 postoperative years than cemented stems (RR = 8, CI: 5–14). The 5 most common uncemented cups had no increased risk of revision for any reason when compared with the 5 most commonly used cemented cups (RR = 0.9, CI: 0.6–1.1). There was no significant difference in the risk of revision due to infection between cemented and uncemented THA. Interpretation Survival of uncemented THA is inferior to that of cemented THA, and this appears to be mainly related to poorer performance of uncemented cups. Uncemented stems perform better than cemented stems; however, unrecognized intraoperative femoral fractures may be an important reason for early failure of uncemented stems. The risk of revision of the most common uncemented cup designs is similar to that of cemented cups, indicating that some of the problems with uncemented cup fixation may have been solved.

Three Hundred and Twenty-one Periprosthetic Femoral Fractures

BACKGROUND The purpose of this study was to determine the demographics, incidence, and results of treatment of periprosthetic fractures in a nationwide observational study. METHODS In the years 1999 and 2000, 321 periprosthetic fractures were reported to the Swedish National Hip Arthroplasty Register. All of the associated hospital records were collected. At the time of follow-up, the Harris hip score, a health-related quality-of-life measure (the EuroQol-5D [EQ-5D] index), and patient satisfaction were used as outcome measurements. A radiologist performed the radiographic evaluation. RESULTS Ninety-one patients, with a mean age of 73.8 years, sustained a fracture after one or several revision procedures, and 230 patients, with a mean age of 77.9 years, sustained a fracture after a primary total hip replacement. Minor trauma, including a fall to the floor, and a spontaneous fracture were the main etiologies for the injuries. A high number of patients had a loose stem at the time of the fracture (66% in the primary replacement group and 51% in the revision group). Eighty-eight percent of the fractures were classified as Vancouver type B; however, there was difficulty with preoperative categorization of the fractures radiographically. There was a high failure rate resulting in a low short to mid-term prosthetic survival rate. The sixty-six-month survival rate for the entire fracture group, with reoperation as the end point, was 74.8% +/- 5.0%. One factor associated with fracture risk was implant design. CONCLUSIONS On the basis of these findings, we believe that high-risk patients should have routine radiographic follow-up. Such a routine could identify a loose implant and make intervention possible before a fracture occurred. Furthermore, we recommend an exploration of the joint to test the stability of the implant in patients with a Vancouver type-B fracture in which the stability of the stem is uncertain.

Risk factors for failure after treatment of a periprosthetic fracture of the femur

Periprosthetic fracture of the femur is an uncommon complication after total hip replacement, but appears to be increasing. We undertook a nationwide observational study to determine the risk factors for failure after treatment of these fractures, examining patient- and implant-related factors, the classification of the fractures and the outcome. Between 1979 and 2000, 1049 periprosthetic fractures of the femur were reported to the Swedish National Hip Arthroplasty Register. Of these, 245 had a further operation after failure of their initial management. Data were collected from the Register and hospital records. The material was analysed by the use of Poisson regression models. It was found that the risk of failure of treatment was reduced for Vancouver type B2 injuries (p = 0.0053) if revision of the implant was undertaken (p = 0.0033) or revision and open reduction and internal fixation (p = 0.0039) were performed. Fractures classified as Vancouver type B1 had a significantly higher risk of failure (p = 0.0001). The strongest negative factor was the use of a single plate for fixation (p = 0.001). The most common reasons for failure in this group were loosening of the femoral prosthesis, nonunion and re-fracture. It is probable that many fractures classified as Vancouver type B1 (n = 304), were in reality type B2 fractures with a loose stem which were not recognised. Plate fixation was inadequate in these cases. The difficulty in separating type B1 from type B2 fractures suggests that the prosthesis should be considered as loose until proven otherwise.

Outcome after total hip arthroplasty: Part II. Disease-specific follow-up and the Swedish National Total Hip Arthroplasty Register

The Swedish National Total Hip Arthroplasty Register records primary hip replacements, revisions and surgical technique/environmental factors. The end-point for failure is revision. A prosthesis still in place, however, does not mean success. Clinical and radiographic outcomes should describe in more detail the efficacy of hip replacement surgery instead of the relatively blunt outcome measure that the register can provide. We performed a clinical outcome analysis on patients with primary total hip replacement thus testing the adequacy of the end-point for failure in the Swedish register. 1,113 randomly selected patients who had had total hip replacement surgery between 1986 and 1995 answered a diseasespecific self-administered questionnaire (WOMAC). A cohort of 344 patients was studied, using the Harris Hip Score and a conventional radiographic examination as outcome measures. We found clinical failure rates of 13% and 20% for all implants after 10 years, using 60 points or revision as the definition of failure in the Harris Hip Score and WOMAC, respectively. The result, according to the register during the same period, was a 7% revision rate. The clinical failure rate depended on the type of evaluation tool, definition of failure and demographics, which made it difficult to decide whether there was a need for revision. With the exception of pain measured by the Harris Hip Score, the results showed no significant correlation between clinical failure and radiographic failure. Hence, with the knowledge that there is a difference between the revision rate according to the register and clinical outcome, the strict definition of failure in the register is useful as an end-point for primary hip replacement surgery.

Variables determining outcome in total hip replacement surgery

In this study we hypothesised that anxiety/depression, one of five dimensions in the health-related quality of life (HRQoL) measurement tool EQ-5D, could predict outcome after total hip replacement surgery. Pre-operative and one-year post-operative data from the Swedish Hip Arthroplasty Register, including 6158 patients with primary osteoarthritis of the hip, were analysed. In order to examine the association between anxiety and outcome with respect to pain and satisfaction an analysis of covariance was used. The pre-operative EQ-5D anxiety/depression dimension was a strong predictor for pain relief and patient satisfaction (p < 0.001). Orthopaedic surgeons involved in the care of patients eligible for total hip replacement surgery should be aware that mental health may influence post-operative pain and HRQoL. An appropriate assessment of mental health may enable a modification in the way these patients are managed in order to optimise the outcome after joint replacement surgery.

Increasing risk of prosthetic joint infection after total hip arthroplasty

Background and purpose The risk of revision due to infection after primary total hip arthroplasty (THA) has been reported to be increasing in Norway. We investigated whether this increase is a common feature in the Nordic countries (Denmark, Finland, Norway, and Sweden). Materials and methods The study was based on the Nordic Arthroplasty Register Association (NARA) dataset. 432,168 primary THAs from 1995 to 2009 were included (Denmark: 83,853, Finland 78,106, Norway 88,455, and Sweden 181,754). Adjusted survival analyses were performed using Cox regression models with revision due to infection as the endpoint. The effect of risk factors such as the year of surgery, age, sex, diagnosis, type of prosthesis, and fixation were assessed. Results 2,778 (0.6%) of the primary THAs were revised due to infection. Compared to the period 1995–1999, the relative risk (with 95% CI) of revision due to infection was 1.1 (1.0–1.2) in 2000–2004 and 1.6 (1.4–1.7) in 2005–2009. Adjusted cumulative 5–year revision rates due to infection were 0.46% (0.42–0.50) in 1995–1999, 0.54% (0.50–0.58) in 2000–2004, and 0.71% (0.66–0.76) in 2005–2009. The entire increase in risk of revision due to infection was within 1 year of primary surgery, and most notably in the first 3 months. The risk of revision due to infection increased in all 4 countries. Risk factors for revision due to infection were male sex, hybrid fixation, cement without antibiotics, and THA performed due to inflammatory disease, hip fracture, or femoral head necrosis. None of these risk factors increased in incidence during the study period. Interpretation We found increased relative risk of revision and increased cumulative 5–year revision rates due to infection after primary THA during the period 1995–2009. No change in risk factors in the NARA dataset could explain this increase. We believe that there has been an actual increase in the incidence of prosthetic joint infections after THA.

Use Of 13 Disease Registries In 5 Countries Demonstrates The Potential To Use Outcome Data To Improve Health Care’s Value

As health care systems worldwide struggle with rising costs, a consensus is emerging to refocus reform efforts on value, as determined by the evaluation of patient outcomes relative to costs. One method of using outcome data to improve health care value is the disease registry. An international study of thirteen registries in five countries (Australia, Denmark, Sweden, the United Kingdom, and the United States) suggests that by making outcome data transparent to both practitioners and the public, well-managed registries enable medical professionals to engage in continuous learning and to identify and share best clinical practices. The apparent result: improved health outcomes, often at lower cost. For example, we calculate that if the United States had a registry for hip replacement surgery comparable to one in Sweden that enabled reductions in the rates at which these surgeries are performed a second time to replace or repair hip prostheses, the United States would avoid

Presidential guest address: the Swedish Hip Registry: increasing the sensitivity by patient outcome data.

2 billion of an expected