Revision for aseptic loosening of uncemented cups in 4,352 primary total hip prostheses: A report from the Norwegian Arthroplasty Register

From September 1987 until January 1994 the Norwegian Arthroplasty Register recorded 5,021 primary total hip replacements performed with uncemented acetabular components. We compared the survival until revision for aseptic loosening of the cup, in the 11 commonest types (n 4,352).

The overall cumulative revision rate for the acetabular components was 3.2% after 5 years and 7.1 YO after 6 years, with large differences among the designs.

With the hydroxyapatite (HA)-coated cups and the hemispheric porous-coated cups, the failure rate was less than 0.1 YO. Of the unthreaded hemispheric porous-coated cups, Harris-Galante and Gemini (n 626), none had been revised, and of the HA-coated cups, Atoll and Tropic (n 1,943), only 1 had been revised.

For the threaded uncoated metal-backed cups, the results varied from no revisions of the PM cups (n 148) to a cumulative 6-year revision rate of 21 YO for the Ti-Fit (n 300). The all-polyethylene Endler cups (n 334) had a cumulative revision rate of 14%.

Women and patients with inflammatory arthritis had poorer results. However, the type and the design of the cups were of far greater importance for the results than patient-related factors.     

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.     

A histopathologic study of late aseptic loosening of cemented total hip prostheses.

Eighteen patients being treated for revision total hip arthroplasty for aseptic loosening an average of 9.5 years after primary cemented hip arthroplasty were studied. The patients were found to have been symptomatic an average of one year before revision. Review of the roentgenograms at the time of revision revealed that most patients had moderate to severe loosening of the prostheses by Charnley's criteria. These findings were confirmed at surgery. Study of the tissue surrounding the prostheses suggests that the prominent particles were methylmethacrylate "pearls" caused by cement fragmentation. These particles were surrounded by histiocytes that were actively synthesizing and releasing protein. Cement fragmentation and not polyethylene wear may be the major cause of late aseptic loosening of cemented hip prostheses.     

Operating time and survival of primary total hip replacements: an analysis of 31,745 primary cemented and uncemented total hip replacements from local hospitals reported to the Norwegian Arthroplasty Register 1987-2001

BACKGROUND: Some studies have found a significant decrease in operating time as a result of standardizing programs for hip surgery. To study the influence of operating time (skin to skin) on survival of total hip replacements, we investigated the operating time in local hospitals in Norway. We have found no other large published series of THRs investigating operating time and revision. PATIENTS AND METHODS: The study was based on 31,745 primary THRs reported to the Norwegian Arthroplasty Register from 47 local hospitals during 1987-2001. Operating time was divided into 7 categories, and for each category separate Kaplan-Meier curves and adjusted failure rate ratios were calculated. RESULTS: The mean operating time for all local hospitals in Norway was 96 (68-130) min. Increasing operating volume from less than 10 THRs/hospital/year to more than 200 THRs/hospital/year was associated with a 25-min decrease in mean operating time in cemented THRs and a 35-min decrease in the case of uncemented THRs. With the operating time category of 71-90 min as reference category, cemented THRs that lasted more than 150 min had a two-fold increased (95% CI: 1.6-2.6) revision rate. For uncemented implants, the revision rate was 1.3 times higher (95% CI: 0.8-2.2). Cemented implants with operating time under 51 min and over 90 min were associated with an increased risk of revision due to aseptic loosening. Cemented implants with operating time over 150 min were associated with an increased risk of revision due to infection. INTERPRETATION: Hospitals with long operating times should consider the potential benefit of reducing these times, as this may lead to lower revision rates and increased operating volumes. Shorter operation times could be achieved by standardization programs, but one should bear in mind that for cemented implants very short operating times also increased revision risk due to aseptic loosening.     

Early failures among 14,009 cemented and 1,326 uncemented prostheses for primary coxarthrosis: The Norwegian Arthroplasty Register, 1987-1992

In the Norwegian Arthroplasty Register, 15,335 primary total hip replacements (THR) in patients with primary arthrosis were followed for 0-5.4 years.

The Kaplan-Meier estimate of cumulative failure (revision) after 4.5 years was 2.7 percent for cemented THR, compared to 6.5 percent for uncemented. In patients under 65 years the cumulative revisions for cemented and uncemented THR were 3.3 and 7.9 percent. For the acetabular components, the cumulative failures were 0.6 percent for cemented and 1.7 percent for uncemented, and for femoral components 1.7 and 3.9 percent after 4.5 years.

Adjusting for age and sex using a Cox regression model, 2 times higher rates of failure were found comparing uncemented to cemented THR. The results for uncemented prostheses were more unfavorable in young patients. In men and women under 60, the revision rates were increased 6 and 3 times, respectively, for patients with uncemented THR compared to those with cemented THR.

Restriction of the end-point to revision for aseptic loosening gave results similar to the over-all results. No difference between cemented and uncemented THR was seen for revisions due to infection, whereas the most unfavorable results for uncemented THR were seen when revisions due to causes other than infection and aseptic loosening were considered.     

Failure rates for 4762 revision total hip arthroplasties in the Norwegian Arthroplasty Register

We present the results for 4762 revision total hip arthroplasties with no previous infection in the hip, which were reported to the Norwegian Arthroplasty Register between 1987 and 2003. The ten-year failure rate for revised prostheses was 26% (95% CI 25 to 26). Cox regression analyses were undertaken separately for acetabular and femoral revision components. Cemented revision components without allograft was the reference category. For acetabular components, we found a significantly reduced risk of failure for uncemented revisions both with (relative risk (RR) = 0.66; 95% CI 0.43 to 0.99) and without (RR = 0.37; 95% CI 0.22 to 0.61) allograft. For femoral components, we found a significantly reduced risk of failure for uncemented revisions, both with (RR = 0.27; 95% CI 0.16 to 0.46) and without (RR = 0.22; 95% CI 0.11 to 0.46) unimpacted allograft. This reduced risk of failure also applied to cemented revision components with allograft (RR = 0.53; 95% CI 0.33 to 0.84) and with impaction bone grafting (RR = 0.34; 95% CI 0.19 to 0.62). Revision prostheses have generally inferior results when compared with primary prostheses. Recementation without allograft, and uncemented revision with bone impaction, were associated with worse results than the other revision techniques which we studied.     

Revision total hip arthroplasty using uncemented components: preliminary report

Revision of failed cemented total hip arthroplasties represents a major technical challenge to orthopaedic surgeons. One of the problems encountered is loss of femoral bone stock, making restoration of prosthetic stability difficult. Revision with uncemented components may allow healing of bone defects.     

18 years of results with cemented primary hip prostheses in the Norwegian Arthroplasty Register: Concerns about some newer implants

Background and purpose Few studies have compared the long-term survival of cemented primary total hip arthroplasties (THAs), and several prostheses have been used without adequate knowledge of their endurance. We studied long-term outcome based on data in the Norwegian Arthroplasty Register.Patients and methods The 10 most used prosthesis brands in 62,305 primary Palacos or Simplex cemented THAs reported to the Register from 1987 through 2007 were included. Survival analyses with revision as endpoint (for any cause or for aseptic loosening) were performed using Kaplan-Meier and multiple Cox regression with time-dependent covariates. Revision rate ratios (RRs) were estimated for the follow-up intervals: 0–5, 6–10, and > 10 years.Results 5 prosthesis brands (cup/stem combinations) (Charnley, Exeter, Titan, Spectron/ITH, Link IP/Lubinus SP; n = 24,728) were investigated with 0–20 year follow-up (inserted 1987–1997). After 18 years, 11% (95% CI: 10.6–12.1) were revised for any cause and 8.4% (7.7–9.1) for aseptic loosening. Beyond 10 years of follow-up, the Charnley cup had a lower revision rate due to aseptic loosening than Exeter (RR = 1.8) and Spectron (RR = 2.4) cups. For stems, beyond 10 years we did not find statistically significant differences comparing Charnley with Titan, ITH, and SP stems, but the Exeter stem had better results (RR = 0.5). 10 prosthesis brands (9 cups in combination with 6 stems; n = 37,577) were investigated with 0–10 years of follow-up (inserted from 1998 through 2007). The Charnley cup had a lower revision rate due to aseptic loosening than all cups except the IP. Beyond 5 years follow-up, the Reflection All-Poly cup had a 14 times higher revision rate. For stems, beyond 5 years the Spectron-EF (RR = 6.1) and Titan (RR = 5.5) stems had higher revision rates due to aseptic loosening than Charnley. The analyses also showed a marked improvement in Charnley results between the periods 1987–1997 and 1998–2007.Interpretation We observed clinically important differences between cemented prosthesis brands and identified inferior results for previously largely undocumented prostheses, including the commonly used prosthesis combination Reflection All-Poly/Spectron-EF. The results were, however, satisfactory according to international standards.     

Femoral head size is a risk factor for total hip luxation: a study of 42,987 primary hip arthroplasties from the Norwegian Arthroplasty Register

On the basis of the Norwegian Arthroplasty Register, which has recorded nearly all primary hip prostheses and revisions in Norway since 1987, we studied risk factors for prosthesis luxation leading to revision. 7 prosthesis brand combinations used in 42,987 primary operations were included from 1987-2000. We found that femoral head size was an important risk factor; 28 mm heads led to revision more often than 32 mm ones (failure rate ratio (FRR) 4.0, 95% confidence interval (CI) 2.2-7.3). Charnley (22 mm head) performed equally well or better than the 28 mm heads. The Exeter stem and cup is the type of prosthesis on the Norwegian market with more than two femoral head sizes (26, 28, 30, 32 mm) and 26 mm heads led to revision due to luxation significantly more often than 30 mm heads (FRR 4.1, 95%CI 2.2-8.1). Old age, preoperative diagnosis, and choice of prosthesis brand combination were also important factors affecting the revision rate due to luxation. A posterior approach increased the risk of revision more than a lateral one (FRR 1.9, 95% CI 1.4-2.5). Gender, trochanteric osteotomy and duration of the operation did not affect the results.     

Revision total hip arthroplasty with an uncemented primary stem in 79 patients

INTRODUCTION: Revision in THA continues to be a technical challenge because of difficulties in fixation of the femoral component in mostly deficient bone in the proximal femur. In cases with minor cortical defects, the use of primary stems in revision surgery has also been described by some authors. MATERIALS AND METHODS: Seventy-nine patients with minor femoral bone defects were reviewed retrospectively (mean follow-up 6.8 +/- 3.9 years), who underwent a femoral component revision surgery using the uncemented primary Bicontact stem (Aesculap, Tuttlingen, Germany). Furthermore, the radiographs (anteroposterior and lateral) before, after surgery and at latest follow-up were analysed concerning femoral defects, proximal bone loss, and to determine the quality of bony fixation. RESULTS: The average Harris hip score (HHS) was 42.2 +/- 20.8 preoperative and improved to 78.9 +/- 12.5 at latest follow-up (p < 0.001). Motion Score increased significantly from 2.7 +/- 1.9 to 3.5 +/- 1.4 (p < 0.05) and pain score decreased significantly from 5.7 +/- 2.9 to 3.6 +/- 2.4 (p = 0.005). During follow-up there were only four re-revisions within 2 years after revision. The results and clinical outcome of this study correspond to those published before, using primary cementless stems in cases of revision. CONCLUSION: Therefore, the primary uncemented Bicontact stem appears to be a good alternative to other revision systems in well-selected femoral revision cases with minor defects.     

Hip disease and the prognosis of total hip replacements. A review of 53,698 primary total hip replacements reported to the Norwegian Arthroplasty Register 1987-99

We studied the rates of revision for 53,698 primary total hip replacements (THRs) in nine different groups of disease. Factors which have previously been shown to be associated with increased risk of revision, such as male gender, young age, or certain types of uncemented prosthesis, showed important differences between the diagnostic groups. Without adjustment for these factors we observed an increased risk of revision in patients with paediatric hip diseases and in a small heterogeneous 'other' group, compared with patients with primary osteoarthritis. Most differences were reduced or disappeared when an adjustment for the prognostic factors was made. After adjustment, an increased relative risk (RR) of revision compared with primary osteoarthritis was seen in hips with complications after fracture of the femoral neck (RR = 1.3, p = 0.0005), in hips with congenital dislocation (RR = 1.3, p = 0.03), and in the heterogenous 'other' group. The analyses were also undertaken in a more homogenous subgroup of 16,217 patients which had a Charnley prosthesis implanted with high-viscosity cement. The only difference in this group was an increased risk for revision in patients who had undergone THR for complications after fracture of the femoral neck (RR = 1.5, p = 0.0005). THR for diagnoses seen mainly among young patients had a good prognosis, but they had more often received inferior uncemented implants. If a cemented Charnley prosthesis is used, the type of disease leading to THR seems in most cases to have only a minor influence on the survival of the prosthesis.     

Validation of data in the Norwegian Arthroplasty Register and the Norwegian Patient Register : 5,134 primary total hip arthroplasties and revisions operated at a single hospital between 1987 and 2003

Background?The usefulness of a national medical register relies on the completeness and quality of the data reported. The data recorded must therefore be validated to prevent systematic errors, which can cause bias in reports and study conclusions.

Patients and methods?We compared the number of hip replacements reported to the Norwegian Arthroplasty Register (NAR), 1987–2003, and to the Norwegian Patient Register (NPR), 1999–2002, with data recorded at a local hospital. The date of operation and the index hip were further validated to find inaccurately recorded data in the NAR. Kaplan-Meier estimated survival curves were compared to evaluate the possible influence of missing data.

Results?Of 5,134 operations performed at a local hospital, 19 (0.4%) had not been reported to the NAR. Completeness of registration was poorer for revisions (1.2%) than for primary operations (0.2%). Among 86 Girdlestone revisions (removal of the prosthesis only), 9 (11%) had not been reported to the NAR. Missing data on revisions, however, had only a minor influence on survival analyses. The date of the operation had been recorded incorrectly in 56 cases (1.1%), and the index hip in 12 cases (0.2%). The surgeon was responsible for 85% of these errors. Comparisons with data reported to the NPR, 1999–2002, showed that 3.4% of operations at the local hospital had not been reported to the NPR.

Interpretation?Only 0.4% of the data from a local hospital was missing in the NAR, as opposed to the NPR where 3.4% was missing. The information recorded in the NAR appears to have been valid and reliable throughout the entire period, and provides an excellent basis for clinically relevant information regarding total hip arthroplasty.

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Results of 189 wrist replacements. A report from the Norwegian Arthroplasty Register

Background and purpose

There is very little literature on the long-term outcome of wrist replacements. The Norwegian Arthroplasty Register has registered wrist replacements since 1994. We report on the total wrist replacements and their revision rates over a 16-year period.

Material and methods

189 patients with 189 primary wrist replacements (90 Biax prostheses (80 of which were cementless), 23 cementless Elos prostheses, and 76 cementless Gibbon prostheses), operated during the period 1994–2009 were identified in the Norwegian Arthroplasty Register. Prosthesis survival was analyzed using Cox regression analyses. The 3 implant designs were compared and time trends were analyzed.

Results

The 5-year survival was 78% (95% CI: 70–85) and the 10-year survival was 71% (CI: 59–80). Prosthesis survival was 85% (CI: 78–93) at 5 years for the Biax prosthesis, 77% (CI: 30–90) at 4 years for the Gibbon prosthesis, and 57% (CI: 33–81) at 5 years for the Elos prosthesis. There was no statistically significant influence of age, diagnosis, or year of operation on the risk of revision, but females had a higher revision rate than males (RR = 3, CI: 1–7). The number of wrist replacements performed due to osteoarthritis increased with time, but no such change was apparent for inflammatory arthritis.

Interpretation

The survival of the total wrist arthroplasties studied was similar to that in other studies of wrist arthroplasties, but it was still not as good as that for most total knee and hip arthroplasties. However, a failed wrist arthroplasty still leaves the option of a well-functioning arthrodesis.The body of literature on wrist arthroplasty is increasing, but most studies have dealt with a single prosthesis design or have compared the outcome of wrist prosthesis to that of wrist fusion. Furthermore, most studies have been on rheumatoid patients. To our knowledge, no randomized trials comparing different designs have ever been published.Wrist arthroplasty with silicone implants was first popularized by Swanson in the 1960s (Swanson 1973). The early results of these were promising. Unfortunately, with longer follow-up, mechanical failure became apparent and severe inflammatory reaction caused by silicone disintegration ensued ( Smith et al. 1985, Brase and Millender 1986, Jolly et al. 1992).The second-generation wrist prostheses introduced in the 1970s typically included two metal components that articulated by means of a ball-and-socket or a hemispheric design (Meuli 1973, Volz 1976). Most of these prostheses were taken off the market because of problems of joint imbalance and dislocation (Lorei et al. 1997, Carlson and Simmons 1998, Vogelin and Nagy 2003).The third-generation of wrist prostheses represents an effort to reconstruct the center of wrist motion in order to prevent imbalance and dislocation (Cavaliere and Chung 2008).The results of total wrist arthroplasy in terms of prosthesis survival have generally been poor compared to most other prostheses. In 2 studies in which the Biax prosthesis—a cementless third-generation implant—was used, the 5-year survival was found to be 83% (Cobb and Beckenbaugh 1996), and the 8-year survival was also 83% (Takwale et al. 2002).In this study, we estimated the incidence, prosthesis survival, and causes of and risk factors for revision of wrist arthroplasties using data from the population-based Norwegian Arthroplasty Register.     

Increasing risk of revision due to deep infection after hip arthroplasty: A study on 97,344 primary total hip replacements in the Norwegian Arthroplasty Register from 1987 to 2007

Background and purpose Over the decades, improvements in surgery and perioperative routines have reduced the incidence of deep infections after total hip arthroplasty (THA). There is, however, some evidence to suggest that the incidence of infection is increasing again. We assessed the risk of revision due to deep infection for primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 1987–2007.Method We included all primary cemented and uncemented THAs reported to the NAR from September 15, 1987 to January 1, 2008 and performed adjusted Cox regression analyses with the first revision due to deep infection as endpoint. Changes in revision rate as a function of the year of operation were investigated.Results Of the 97,344 primary THAs that met the inclusion criteria, 614 THAs had been revised due to deep infection (5-year survival 99.46%). Risk of revision due to deep infection increased throughout the period studied. Compared to the THAs implanted in 1987–1992, the risk of revision due to infection was 1.3 times higher (95%CI: 1.0–1.7) for those implanted in 1993–1997, 1.5 times (95% CI: 1.2–2.0) for those implanted in 1998–2002, and 3.0 times (95% CI: 2.2–4.0) for those implanted in 2003–2007. The most pronounced increase in risk of being revised due to deep infection was for the subgroup of uncemented THAs from 2003–2007, which had an increase of 5 times (95% CI: 2.6–11) compared to uncemented THAs from 1987–1992.Interpretation The incidence of deep infection after THA increased during the period 1987–2007. Concomitant changes in confounding factors, however, complicate the interpretation of the results.     

Validation of data in the Norwegian Arthroplasty Register and the Norwegian Patient Register: 5,134 primary total hip arthroplasties and revisions operated at a single hospital between 1987 and 2003

Background The usefulness of a national medical register relies on the completeness and quality of the data reported. The data recorded must therefore be validated to prevent systematic errors, which can cause bias in reports and study conclusions.

Patients and methods We compared the number of hip replacements reported to the Norwegian Arthroplasty Register (NAR), 1987-2003, and to the Norwegian Patient Register (NPR), 1999-2002, with data recorded at a local hospital. The date of operation and the index hip were further validated to find inaccurately recorded data in the NAR. Kaplan-Meier estimated survival curves were compared to evaluate the possible influence of missing data.

Results Of 5,134 operations performed at a local hospital, 19 (0.4%) had not been reported to the NAR. Completeness of registration was poorer for revisions (1.2%) than for primary operations (0.2%). Among 86 Girdlestone revisions (removal of the prosthesis only), 9 (11%) had not been reported to the NAR. Missing data on revisions, however, had only a minor influence on survival analyses. The date of the operation had been recorded incorrectly in 56 cases (1.1%), and the index hip in 12 cases (0.2%). The surgeon was responsible for 85% of these errors. Comparisons with data reported to the NPR, 1999-2002, showed that 3.4% of operations at the local hospital had not been reported to the NPR.

Interpretation Only 0.4% of the data from a local hospital was missing in the NAR, as opposed to the NPR where 3.4% was missing. The information recorded in the NAR appears to have been valid and reliable throughout the entire period, and provides an excellent basis for clinically relevant information regarding total hip arthroplasty.

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The performance of two hydroxyapatite-coated acetabular cups compared with Charnley cups. From the Norwegian Arthroplasty Register

We have compared the survival of two hydroxyapatite (HA)-coated cups, 1208 Atoll hemispheric and 2641 Tropic threaded, with cemented Charnley all-polyethylene cups (16 021) using the Cox regression model. The Tropic cup used in combination with an alumina ceramic femoral head, had good results, similar to those of the Charnley cup. When used in combination with a stainless-steel head, however, the risk of revision beyond four years was increased 3.4 times for the Tropic cup compared with the Charnley cup (p < 0.001). Over the same period, the Atoll cup had an increased risk of revision of 3.8 times when used with the alumina heads (p < 0.001) and an increased risk of 6.1 times when used with stainless-steel heads (p < 0.001). Revision because of wear and osteolysis was more common with both types of HA-coated cup than with the Charnley cup. The rate of revision of the Atoll cup because of aseptic loosening was also increased. We found that HA-coated cups did not perform better than the Charnley cup.