Introduction

Stem revision with retention of the old cement mantle (cement-in-cement revision) in cases with an intact cement/bone interface is an appealing option. There has been an increasing use of this technique. In 2014 this cement-in- cement technique was used in 10% of all stem revisions reported to the Swedish Hip Arthroplasty Register (SHAR). We analysed the outcome of cement-in-cement stem revisions reported to the SHAR during years 2001–2014

Introduction

Dislocation as a primary cause of revision has been on the increase in Sweden (14% in 2014). The increasing use of Dual Mobility cups (DMC) could well be explained by the increased revision burden due to dislocation, patients undergoing revision having increased comorbidities and reports that dual articular cup designs reduce the risk of dislocation. The aim of this study was to analyze the change in utilization pattern of the dual articular designs used in acetabular revision surgery in Sweden. The short-term survival of DMC was compared to traditional designs.

Summary Statement

We analysed impaction bone grafting used together with cemented or uncemented fixation in acetabular revision surgery. The overall risk for re-revision did not differ between the cemented and uncemented group. However, aseptic loosening was more common in the cemented group.

Summary

Comparison of accuracy and precision in measuring wear using 4 commonly used uncemented cup designs shows small differences in mean and data scatter for marker and model-based RSA.

The effects of surgical approach in total hip replacement on health-related quality of life and long-term pain and satisfaction are unknown. From the Swedish Hip Arthroplasty Register, we extracted data on all patients that had received a total hip replacement for osteoarthritis through either the posterior or the direct lateral approach, with complete pre- and one-year post-operative Patient Reported Outcome Measures (PROMs). A total of 42 233 patients met the inclusion criteria and of these 4962 also had complete six-year PROM data. The posterior approach resulted in an increased mean satisfaction score of 15 (sd 19) vs 18 (sd 22) (p <  0.001) compared with the direct lateral approach. The mean pain score was 13 (sd 17) vs 15 (sd 19) (p < 0.001) and the proportion of patients with no or minimal pain was 78% vs 74% (p < 0.001) favouring the posterior approach. The patients in the posterior approach group reported a superior mean EQ-5D index of 0.79 (sd 0.23) vs 0.77 (sd 0.24) (p < 0.001) and mean EQ score of 76 (sd 20) vs 75 (sd 20) (p < 0.001). All observed differences between the groups persisted after six years follow-up. Although PROMs after THR in general are very good regardless of surgical approach, the results indicate that some patients operated by the direct lateral approach report an inferior outcome compared with the posterior approach. The large number of procedures and the seemingly sustained differences make it likely these findings are clinically relevant.

Cite this article: Bone Joint J 2014;96-B:590–6.

While an increasing amount of arthroplasty articles report comorbidity measures, none have been validated for outcomes. In this study, we compared commonly used International Classification of Diseases-based comorbidity measures with re-operation rates after total hip replacement (THR). Scores used included the Charlson, the Royal College of Surgeons Charlson, and the Elixhauser comorbidity score. We identified a nationwide cohort of 134 423 THRs from the Swedish Hip Arthroplasty Register. Re-operations were registered post-operatively for up to 12 years. The hazard ratio was estimated by Cox’s proportional hazards regression, and we used C-statistics to assess each measure’s ability to predict re-operation. Confounding variables were age, gender, type of implant fixation, hospital category, hospital implant volume and year of surgery.

In the first two years only the Elixhauser score showed any significant relationship with increased risk of re-operation, with increased scores for both one to two and three or more comorbidities. However, the predictive C-statistic in this period for the Elixhauser score was poor (0.52). None of the measures proved to be of any value between two and 12 years. They might be of value in large cohort or registry studies, but not for the individual patient.

Cite this article: Bone Joint J 2013;95-B:1184–91.

In medical research and among health-care providers there has been a marked shift to a focus on patient-reported outcome (PRO) and how it is measured and analysed. In this study from the Swedish Hip Arthroplasty Register we present the development and results of a nationwide, prospective, observational follow-up programme including patient-reported outcome measures (PROMs). The programme started in 2002 and has gradually expanded to include all units performing THA surgery in Sweden. The self-administered PROM protocol comprises the EQ-5D instrument, the Charnley categorization and visual analogue scales (VAS) for pain and satisfaction. These current analyses include 34 960 THAs with complete pre- and one-year postoperative questionnaires.

Patients eligible for THA generally report low health-related quality of life (HRQoL) and suffer from pain. One year post-operatively the mean EQ-5D index increased from 0.41 to 0.78 (p<0.001) which is above the level of an age- and gender-matched population. Pain was reduced from mean VAS 62 to 14 (p<0.001). Females, younger patients and those with Charnley category C reported lower EQ-5D index pre-operatively than males, older patients and Charnley A or B, respectively, did (all p<0.001). In a multivariable regression analysis Charnley category C, male gender and higher age were associated with less improvement in HRQoL (p<0,001). Patients' response rates to the Registry was 86% pre-operatively and 90% one year post-operatively.

Nationwide implementation of a PROM programme requires a structured organization and effective IT solutions. The continuous collection of PROs permits local and national improvement work and allows for further health-economic evaluation.

Background

In Sweden approximately 6000 patients yearly sustain displaced femoral neck fractures. During the last decade there has been a shift towards more arthroplasties at the expense of internal fixation. In 2008 approximately 75% of the dislocated femoral neck fractures in Sweden were treated with arthroplasties. Those patients are typically elderly and frail and the vast majority of them receive hemiarthroplasties. In 2005 a national hemiarthroplasty registration was established as part of the Swedish Hip Arthroplasty Register (SHAR).

We present the development and results of a nationwide, prospective, observational follow-up programme including patient-reported outcome measures (PROMs) for the Swedish Hip Arthroplasty Register. The programme started in 2002 and has gradually expanded to include all units performing total hip replacement in Sweden. The self-administered PROMs protocol comprises the EQ-5D instrument, the Charnley class categorisation and visual analogue scales for pain and satisfaction. These current analyses include 34 960 total hip replacements with complete pre- and one-year post-operative questionnaires.

Patients eligible for total hip replacement generally report low health-related quality of life and suffer from pain. One year post-operatively the mean EQ-5D index increased to above the level of an age- and gender-matched population, with a considerable reduction of pain (p < 0.001). Females, younger patients and those with Charnley category C reported a lower EQ-5D index pre-operatively than males, older patients and Charnley category A or B, respectively (all p < 0.001). In a multivariable regression analysis Charnley category C, male gender and higher age were associated with less improvement in health-related quality of life (p < 0.001).

Nationwide implementation of a PROMs programme requires a structured organisation and effective data capture. Patients’ response rates to the Registry are good. The continuous collection of PROMs permits local and national improvement work and allows for further health-economic evaluation.

Introduction: Revision rate after THA in the younger age groups is still unacceptable high and might up to 20% after 10 years. The aim of this investigation is to evaluate risk factors for later revision in patients younger than 50 years at surgery based on the NARA database (Nordic Arthroplasty Register Association).

Materials and Methods: 14,610 primary THA from Denmark, Sweden, and Norway, operated from 1995 to 2007, were included. 49.4% was males, the diagnosis was idiopathic osteoarthrosis (OA) in 46%, childhood disease in 26%, inflammatory arthritis (IA) in 12%, non-traumatic osteonecrosis in 9% and fracture in 6%. 49% of the THA’s were uncemented, 27% cemented, 14% hybrid, and 8% were inverse hybrid THA’s. Cox multiple regression, adjusted for diagnose, age, gender, calendar year and surgical approach, was used to calculate prosthesis survival with any revision as end-point. RR= relative risk (CI= confidence interval).

Results: The overall 10-year survival was 83%. There was no difference between gender (RR=0.94 (0.82–1.07)). IA had a 37% reduced risk of revision compared with OA (RR=0.67 (0.54–0.84)), whereas there was no difference between childhood disease and primary osteoarthrosis. Overall, cemented, uncemented and reverse hybrid THA had a better survival than hybrid THA. Hybrid THA had 24% increased risk compared with cemented (RR=1.24 (1.04–1.49)). There were no difference between cementless and cemented (RR=1.07 (0.92–1.26)). Interestingly, the inverse THA had lower revision rate than cemented THA in men (RR=0.50 (0.25–0.99)). The risk for revision due to aseptic loosening was lowest in cementless THA and reduced to RR=0.55 (0.44–0.69) compared with cemented THA.

Discussion: and Conclusion: Choice of prosthetic concept for younger patients is still of debate. The present study including only patients younger than 50 years of age, showed that overall cemented, uncemented and reverse hybrid THA, had better survival than traditional hybrid. The risk for revision due to aseptic loosening was higher in cemented than cementless THA.

Background: Hydroxyapatite (HA) coating is widely used for total hip arthroplasty as it has been suggested to improve implant ingrowth and long-term stability. However, the evidence behind the use of HA in femoral stems is ambiguous.

Methods: We investigated a non-cemented, tapered titanium femoral stem that was available either with or without HA coating. This stem had been used in 3,116 total hip arthroplasties (THAs) in 2,608 patients registered in the Swedish Hip Arthroplasty Register (1992–2007). Kaplan-Meier survival analysis and a Cox regression model including type of coating, age, sex, primary diagnosis, and the type of cup fixation were used to calculate adjusted risk ratios (RR) of the risk for revision for various reasons.

Results: 63.7% of the stems were coated with HA, 36.3% were uncoated. It was found that the investigated HA-coated stem had an excellent 10-year survivorship of 97.7% (95% CI 96.5–98.9), and that the stem without HA coating had a 10-year survivorship of 97.6% (95% CI 96.2–99.0) when revision due to any reason was defined as the endpoint. There was no significant difference between these two groups (p> 0.05, log rank Mantel-Cox). A Cox regression model showed that the presence of HA coating did not significantly influence the risk of stem revision due to any reason (RR 1.3; 95% CI 0.7–2.4), or due to aseptic loosening (RR 1.0; 95% CI 0.3–3.4). The risk for revision due to infection, dislocation, or fracture was also not affected by the presence of HA coating.

Interpretation: Our results show HA coating of this non-cemented tapered stem with excellent 10-year survivorship does not affect the risk for revision. The assumed beneficial effect of HA coating of femoral stems in total hip arthroplasty is thus questionable.

Of 960 first-revision total hip replacements (THR) because of deep infection identified in the Swedish Hip Arthroplasty Registry, 16.9% were treated with a permanent implant extraction, while a staged or direct reconstruction revision protocol were employed in 56.2% and 26.9% respectively. The majority of the interventions were performed more than one year after index THR, and the dominating pathogen was coagulase negative staphylococci (CNS). We found a significant shift in types of bacteria over the years (Chi-square test, p smaller than 0.001): an increase in the CNS group and a decrease in Gram-negative aerobes. Patients treated with a permanent resection were generally older (p< 0.001), had more often a previous ipsilateral hip fracture (p< 0.001), and had more frequently Gram-negative infections (p=0.02). No systematic differences in patient characteristics or pathogens were detected between one-stage or two-stage procedures, of which the latter had a median re-implantation time of 2 (range: 0.2–62) months. Of 798 (one- or two-stage) revisions, 60 (7.5%) were revised again due to recurrent infection, with no difference between the two methods, and implying a 10-year survival of 90%; 95% confidence interval (CI95%) 88.2–93.0. Previous surgery for soft-tissue problems (RR 3.2 (CI95% 1.3–7.2)) predicted a worse outcome for one-stage procedures. The prognosis of two-staged revisions improved with increasing re-implantation interval (RR 0.8 (CI95% 0.7–1.0)) per month, and a 6 month interval carried the lowest risk of repeat revision due to infection; RR 0.1 (CI95% 0.0–0.9). Staged revisions in female patients (RR 2.3, (CI95% 0.9–5.7)) and with Staphylococcus aureus infections (RR 2.3 (CI95% 0.9–5.5)) predicted a worse outcome. Ten-year survival with repeat revision for aseptic loosening as end-point was 89% (95%CI 85.7–92.0), but decreased to 79% when all reasons for revision were taken into account (95%CI 75.0–82.3) mainly because of revision for peri-prosthetic fractures.

The results suggest that direct and staged revision protocols can have a good prognosis on a national level, but efforts must be made to counteract periprosthetic fractures and the high incidence of permanent implant extraction in elderly patients.

Introduction: There is an increasing interest in surface replacement arthroplasty (SRA) as an alternative to conventional THA (cTHA) in young and active patients. However, there has been considerable variability in reported outcomes. National joint registry reports have shown increased revision rates compared to cTHA. We analysed outcome measured as non-septic revision rate within two years for SRA in the NARA data base (Nordic Arthroplasty Register Association).

Materials and Methods: 1638 SRA and 163802 cTHA with age up to 73 years and a non-fracture diagnosis, operated from 1995 to 2007, were compared using Cox multiple regression including age, gender, diagnosis, nation and prosthesis type with cTHA divided into cemented, uncemented, hybrid and reversed hybrid fixation. Men below 50 years of age (460 SRA and 7185 cTHA) were analysed as a subset. The SRA cohort with a mean follow-up 1,8 years was also analysed with the same method including age, gender, diagnosis, number of performed SRA per hospital and the four most commonly used prosthesis designs. In an additional analysis femoral head diameter was added, reducing the number of cases to 1552. results are presented as relative risk (RR) with 95 % confidence interval(CI).

Results: SRA had a more than twofold increased revision risk compared to cTHA, RR=2,50 (1,67–3,70), which increased to 3,63 (2,42–5,44) when compared with all cemented THA. In the subpopulation of men below 50 years of age, there was no difference between SRA and any of the cTHA cathegories. Within the SRA group RR was reduced by male gender, RR=0,46 (0,25–0,86), in hospital performing > 70 SRA (RR=0,26, 0,11–0,60) and with use of BHR (Birmingham Hip Resurfacing) compared to all other designs (RR=0,27, 0,12–0,61). The size of the femoral head diameter had no significant influence on the early revision rate.

Discussion and Conclusion: Surface replacement arthroplasty has an increased risk of early revision compared to conventional and cemented THA except for men below 50 years of age. There is a learning curve on the hospital level. Cases with secondary osteoarthritis were comparatively few and were mainly caused by pediatric hip disease. SRA might become an alternative for young men, but our follow up is too short to determine if this indication remains in the longer perspective.

Introduction: Up to now comparisons and pooling of data between the Scandinavian arthroplasty registers have been restrained by use of separate and incompatible data systems.

Purpose: To create a common Scandinavian database for hip arthroplasties and to compare demographics and results between the Scandinavian countries.

Materials and methods: For this study we selected primary total hip prostheses (THR) from 1995–2006. A common code set was made, and after de-identification of the patients’ identity, including deletion of the national civil registration numbers, Denmark, Sweden, and Norway delivered data. Kaplan-Meier and Cox multiple regression, with adjustment for diagnosis, age, and gender, were used to calculate prosthesis survival, with any revision as end-point.

Results: 280,201 operations were included (Denmark 69,242, Sweden 140,821, Norway 70,138). Female patients constituted 60% in Denmark and Sweden and 70% in Norway. In Denmark, Sweden, and Norway childhood disease constituted 3.1%, 1.8%, and 8.7% respectively. The posterior approach was used in 91% of cases in Denmark, 60% in Sweden, and 24% in Norway. Cemented THRs were applied in 46% of patients in Denmark, 89% in Sweden, and in 79% in Norway. Resurfacing hips constituted 0.5% or less in all countries.

9,596 of the 280,201 primary THRs, had been revised. Ten-years survival was 91.9% (95% CI: 91.5 – 92.3) in Denmark, 93.9% (95% CI: 93.6–94.1) in Sweden, and 92.6% (95% CI: 92.3–93.0) in Norway.

In Sweden and Norway 23% of revisions were due to dislocation, compared to 34% in Denmark. Replacement of only cup or liner constituted 29% of the revisions in Sweden, 33% in Norway, and 44% in Denmark.

Conclusion: This unique database is now functioning, and has showed differences among the countries concerning demographics, prosthesis fixation, prosthesis survival, and reasons for revisions. The large number of THRs in this database significantly enhances our perspectives for future research, especially in diagnostic- and treatment groups with too small numbers in each separate

Background: Hemiarthroplasty of the hip is a common procedure, but information about implants and outcome is scarce. In Sweden the number of hemiarthroplasties has increased from 200 in 1998 to 4181 in 2007.

Material and Methods: Nationwide registration started in 2005. 100% of the hospitals participates, and 96% of the hemi-procedures are registrered. An analysis of 12 245 cases operated 2005–07 is presented.

Results: In the Register the mean age at surgery is 84 years (SD 7.0, 73% female). 93% are operated due to acute fracture and 6% due to failed internal fracture fixation. Cemented fixation has been used in 92% and a posterior approach in about half of the cases (52%). The Lubinus and Exeter stems are most common (41 and 23%). The Austin-Moore design has decreased from 9 to 2% during the study period.

3.2% of the patients (hips) have been reoperated, most commonly because of dislocation. Multiple reoperations are common. Male gender, secondary procedure and uncemented stem are associated with increased reoperation risk with 1.2, 1.7 and 1.8 times (1.2, CI: 1.0–1.6; 1.7, 1.3–2.3; 1.8 1.4–2.5). Use of uncemented fixation resulted in increased risk of reoperation, also with exclusion of uncemented Austin-Moore prostheses (1.8 times, 1.1–2.8).

In a separate analysis of the two most frequent designs, use of bipolar head increased the risk of revision twice (1.4–2.8) compared to unipolar head when adjusting for other risk factors. This may reflect that fitter and more active individuals get a bipolar prosthesis and are more prone to become revised should complications occur or a true increase of complications when using bipolar head. A further analysis is in progress.

Use of dorsal approach (1.6, 1.2–2.2), Austin-Moore (1.8, 1.1–3.1) and Thompson prostheses (1.8, 1.5–2.8) increased the risk of revision because of dislocation.

Summary: When treating fracture patients with hemi-arthroplasty we recommend that a well documented cemented implant with different off-set options should be used via an anterolateral approach. Use of bipolar heads may increase the risk of revision.

Background: Hydroxyapatite (HA) is the main inorganic component of bone, and HA coating is widely used on acetabular cups in hip arthroplasty. It has been suggested that this surface finish improves cup survival, but there is little evidence to support this.

Patients and methods: All patients registered in the Swedish Hip Arthroplasty Register between 1992 and 2007 with an uncemented acetabular implant that was available with or without HA coating were identified. A study population of 8,043 hips with the most common cup types manufactured either with or without HA coating (Harris-Galante, Romanus and Trilogy) was investigated. Kaplan-Meier survival analysis and a Cox regression model including type of coating, age, sex, primary diagnosis, cup type, and type of stem fixation were used to calculate adjusted risk ratios (RR) of the risk for revision.

Results: Kaplan-Meier analysis of all patients indicated a non-significant trend towards inferior performance of the HA-coated cups (p=0.78). When stratified for age, Kaplan-Meier analysis revealed inferior survival of HA-coated cups when compared to non-coated cups in the age group < 50 years (p=0.031). A Cox regression model showed that HA coating was a significant risk factor for cup revision due to aseptic loosening (adjusted RR 1.645; 95% CI 1.315–2.058). Age at primary arthroplasty < 50 years, a diagnosis of paediatric hip disease, a cemented stem, and the Romanus and Harris-Galante cup types were also associated with significantly increased risk for cup revision due to aseptic loosening. There was no difference in the hazard patterns when the risk for revision for any reason was chosen as the endpoint of the analysis. The risk for revision due to infection was not influenced by the type of coating.

Discussion: Our results derived from register data on 8,043 hips indicate that HA coating does not enhance survival of cups when using aseptic loosening as an endpoint. On the contrary, hydroxyapatite coating is a significant risk factor for cup revision due to aseptic loosening when adjusted for other covariates such as age, sex, cup design and primary diagnosis. HA coating cannot be generally recommended as a surface treatment of acetabular cups in younger patients. This conclusion is medically and economically relevant, as many young patients today receive HA-coated cups, and because HA-coated implants are more expensive.

In a previous report from a randomised study we reported excellent fixation and less proximal periprosthetic bone mineral loss around the Epoch design at 2 years follow-up when compared with a solid stem of similar design. We now present the 7 years follow-up.

Forty consecutive patients (20 men, 10 women, mean age 57, 41–74) with non-inflammatory osteoarthritis were randomised to receive either a cementless porous-coated composite stem with reduced stiffness (Epoch) or a cementless stiff stem with a porous coating (Anatomic). Patients were followed for 7 years with repeated evaluations using radiostereometry, DXA, conventional radiography and Harris Hip Score (HHS).

At 7 years 1 stem had been revised (Anatomic) due to late infection. Subsidence and stem rotations were close to zero without any difference between the two groups (p> 0,12). Median wear rates were lower than expected (0.4mm up to 7 years) for both stem designs. At 2 years loss bone mineral density was less in Gruen regions 1, 2, 6 and 7 for the Epoch stems (p< 0.04), but this difference tended to disappear with time. At 7 years only the calcar region (Gruen region 7) had significantly denser bone in the Epoch group (p< 0.001). The HHS scores did not differ (median 98, 51–100). No stem was radiographically loose.

The Epoch stem achieved excellent fixation. Wear rates were low despite use of conventionally gamma-sterilised polyethylene. This low modulus stem had positive effects on early proximal bone remodeling, but this effect decreased with time.

Earlier reports have shown that surface treatment influences the survivorship of tapered hip implants. To assess the role of surface finish for other stem shapes we evaluated three modifications of the Lubinus SP2 stem.

Eighty patients (31 male, 49 female, 68 (46–78 years), 84 hips) with non-inflammatory arthrosis randomly received either stem type: cemented matte (M, standard design), polymethylmetacrylate-coated (PC) or polished (P, collarless). Component fixation and wear were studied with radiostereometric analysis and the bone mineral density was measured around the stem in 40 patients at 6 months, 1, 2 and 5 years.

The polished design showed increased distal migration at 6 months (Mean and range) P: −0.21mm(−0.52 to 0.09), M: −0.07mm (−0.34 to 0.26), PC: −0.03 (−0.18 to 0.18) and at 5 years P:0.49mm (−1.46 to 0.16), M: −0.18mm (−0.80 to 0.33), PC: −0.12mm (−1.40 to 0.12 (p< 0.0001). This increased subsidence occurred inside the cement mantle. The rotations of the stem did not differ (p> 0.4). Neither did the migration and the wear (p> 0.1). After 1 and 2 years the polished stems had lost significantly less bone mineral in Gruen zones 1, 2, 6 and 7 (p 0.004 to 0.03). After 5 years this difference had disappeared. The Harris Hip Scores did not differ.

A polished surface without collar on an anteverted stem design resulted in increased subsidence of the stem inside the cement mantle. The improved bone remodeling around the polished version seemed to be transient.

Between 1999 and 2005, 10 264 patients who had undergone total hip replacement (THR) for subcapital fracture of the hip were compared with 76 520 in whom THR had been performed for other reasons. All the cases were identified through the Swedish Hip Arthroplasty Register. The THRs performed as primary treatment for fracture were also compared with those done after failure of internal fixation.

After seven years the rate of revision was higher in THR after fracture (4.4% vs 2.9%). Dislocation and periprosthetic fracture were the most common causes of revision. The risk was higher in men than in women. The type of femoral component and the surgical approach influenced the risk. After correction for gender, type of component and the surgical approach the revision rates were similar in the primary and secondary fracture THR groups.

Total hip replacement is therefore a safe method for both the primary and secondary management of fracture of the hip.

We have carried out a radiostereometric study of 50 patients (54 knees) with osteoarthritis of the knee who were randomly allocated to receive a cemented or a hydroxyapatite-coated femoral component for total knee replacement. The patients were also stratified to receive one of three types of articulating surface (standard, rotating platform, Freeman-Samuelson (FS)1000) all based on the Freeman-Samuelson design. The tibial components were cemented in all cases. Radiostereometry was performed post-operatively and at 3, 12 and 24 months. The analysis was restricted to rotation of the femoral component over time.

After two years, rotation of the femoral components in the transverse, longitudinal and sagittal planes did not differ between the cemented and the hydroxyapatite-coated implants (p = 0.2 to 0.9).

In total knee replacements with a rotating platform, the femoral component tended to tilt more posteriorly than in the other two designs, regardless of the choice of fixation (cemented or hydroxyapatite-coated, p = 0.04). The standard version of the femoral component, whether cemented or hydroxyapatite-coated, rotated more into valgus than was observed with the rotating-platform and FS1000 designs (p = 0.005). The increased constraint provided by the FS1000 component did not appear to have any adverse effect on fixation of the femoral component.