The incidence of knee arthroplasty for primary osteoarthritis grows rapidly among baby boomers: a population-based study in Finland.

OBJECTIVE: Total knee arthroplasty (TKA) is a commonly used treatment for severe primary knee osteoarthritis (OA) that is refractory to conservative treatment. Despite the presumed increase in the use of this treatment modality in younger patients, there are few published data concerning this. The aim of our study was to examine the changes in the age- and sex-standardized incidence of TKA and unicondylar knee arthroplasty (UKA) in Finland during 1980-2006 and to identify factors that might affect the incidence during this period. METHODS: We obtained data on UKAs and TKAs from the Finnish Arthroplasty Registry and population data from Statistics Finland to analyze the incidence of UKAs and TKAs in Finland for the period 1980-2006. The effects of sex, age group, and hospital volume on the incidence of these procedures were also evaluated. RESULTS: The annual cumulative incidence of UKAs and TKAs has increased rapidly from 1980 to 2006 among 30-59-year-old inhabitants of Finland. For UKAs, the incidence increased from 0.2 per 100,000 inhabitants to 10 per 100,000, and for TKAs, the incidence increased from 0.5 per 100,000 to 65 per 100,000. The incidence remained higher among women during the entire study period. Most of the increase occurred among patients ages 50-59 years. The incidence grew more rapidly in low-volume and intermediate-volume hospitals. CONCLUSION: We demonstrated a rapid increase in the incidence of arthroplasty among patients with primary knee OA in Finland, especially in those ages 50-59 years. There was no single explanatory factor behind this finding, although some of the growth might be due to the increased incidence noted in low- and intermediate-volume hospitals.

Results of 3,668 primary total hip replacements for primary osteoarthritis in patients under the age of 55 years.

BACKGROUND AND PURPOSE: In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland. PATIENTS AND METHODS: 3,668 implants fulfilled our inclusion criteria. The previous data included years 1980-2001, whereas the current study includes years 1987-2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987-1996 and those operated 1997-2006. RESULTS: The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987-1996 (62%; 95% CI: 57-67) and cementless group 2 (58%; CI: 52-66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62-80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987-1996 (0.49; CI: 0.32-0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001). INTERPRETATION: Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland.

Cemented versus cementless total hip replacements in patients fifty-five years of age or older with rheumatoid arthritis.

BACKGROUND: results obtained from single-center studies indicate that a cemented total hip replacement is the treatment of choice for the management of patients over fifty-five years of age with rheumatoid arthritis. The aim of this study was to analyze population-based survival rates for cemented and cementless total hip replacements in patients aged fifty-five years or over with rheumatoid arthritis in Finland. METHODS: between 1980 and 2006, a total of 6000 primary total hip replacements performed for the management of rheumatoid arthritis in patients who were fifty-five years of age or older were entered in the Finnish Arthroplasty Registry. 4019 of them fulfilled our inclusion criteria and were subjected to analysis. The implants were classified into one of three possible groups: (1) a cementless group (a noncemented proximally porous-coated stem and a noncemented porous-coated press-fit cup), (2) a cemented group 1 (a cemented, loaded-taper stem combined with a cemented, all-polyethylene cup), or (3) a cemented group 2 (a cemented, composite-beam stem with a cemented, all-polyethylene cup). RESULTS: cementless stems and cups, analyzed separately, had a significantly lower risk of revision for aseptic loosening than cemented implants in patients who were fifty-five years of age or older with rheumatoid arthritis. The fifteen-year survival rate of cementless total hip replacements (80%) was comparable with the rates of the cemented groups (86% in cemented group 1 and 79% in cemented group 2) when revisions for any reason were used as the end point. CONCLUSIONS: cementless and cemented total hip replacements produced comparable long-term results in patients who were fifty-five years of age or older with rheumatoid arthritis. LEVEL OF EVIDENCE: therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Early results of 827 trabecular metal revision shells in acetabular revision.

We evaluated the survival of 827 acetabular revisions with Trabecular Metal Revision Shell using data from a nationwide arthroplasty register. The mean age of the patients was 69.1 years. The 3-year overall survivorship was 92% (95% confidence interval, 88-95), which coincides with earlier reports. Revision rate for aseptic loosening was only 2%. The most common reason for revision was dislocation of the prosthesis with or without malposition of the socket (60%). Age was found to have significant effect on cup survivorship: each additional year in age decreased the risk of revision by 2.4% (95 % confidence interval, 0.1-4.7; P = .044). We found no differences in survival rates between aseptic and septic revisions. Furthermore, sex, diagnosis, and hospital volume did not affect the survival.

Results of total knee replacement with a cruciate-retaining model for severe valgus deformity--a study of 48 patients followed for an average of 9 years.

The objectives of the present study were to find out the results and the factors affecting survival after primary knee arthroplasty with a cruciate-retaining prosthesis in severe valgus deformity. Forty-eight patients (52 knees) participated in the current follow-up study. All patients were followed at least 5 years or to first revision. Mean follow-up time was 9 years (range, 1 to 17 years).The Kaplan-Meier analysis revealed 79% (95% CI 68% to 91%) survival rate with revision for any reason and 81% (95% CI 70% to 93%) survival rate with revision for instability as an endpoint at 10 years. Preoperatively TFA was 23° (range, 15°-51°) in valgus and 7° (range, 21° valgus-4° varus) in valgus postoperatively. Of the 14 re-operated patients, eight were revised because of progressive postoperative medial collateral ligament instability. All re-operations were performed during the first 4 years of the follow-up. The mean TFA was 15.5° valgus postoperatively for those eight and the odds ratio for a revision was 2 (95% CI 1-3, p = 0.025) when compared to the rest of the study population. The residual valgus deformity increases the risk of re-operation and it should be avoided. If proper soft-tissue balance cannot be achieved or there is no functional medial collateral ligament present more constrained implants should be used. In selected cases where both bony correction and ligament balancing have properly been achieved the use of a cruciate-retaining type of prosthesis is justified.

Is longer waiting time for total knee replacement associated with health outcomes and medication costs? Randomized clinical trial.

BACKGROUND: The aim of this prospective randomized study was to evaluate the effect of waiting time (WT) on health-related quality of life (HRQoL), knee pain and physical function, and the use and costs of medication of patients awaiting total knee replacement. METHODS: When placed on the waiting list, 438 patients were randomized into a short waiting time (SWT ≤ 3 months) or a nonfixed waiting time (NFWT > 3 months) group. HRQoL was measured by the 15D, and pain and physical function by modified Knee Society Clinical Rating System at baseline, admission, and 3 and 12 months postoperatively. The costs of medication due to osteoarthritis were calculated at the same measurement points. All analyses were performed using the intention-to-treat principle. RESULTS: The mean WT was 94 and 239 days in the SWT and NFWT groups, respectively. Apart from higher weekly cost of medication in the SWT group at admission and better HRQoL in the NFWT group 1 year postoperatively, there were no statistically significant differences between the groups in other outcomes during the follow-up. CONCLUSION: Those in the SWT group had higher weekly costs of medication at admission, and reached better HRQoL 3 months earlier than those in the NFWT group, but the latter had better HRQoL after operation. Otherwise, the length of WT was not associated with different health and HRQoL outcomes in the groups.

A retrospective comparative study of mortality and causes of death among patients with metal-on-metal and metal-on-polyethylene total hip prostheses in primary osteoarthritis after a long-term follow-up.

BACKGROUND: All patients with total hip arthroplasty (THA), especially those with metal-on-metal (MM) THA, are exposed to metallic particles and ions, which may cause total or site-specific mortality. We analyzed the causes of total and site-specific mortality among a cohort of patients with MM and with metal-on-polyethylene (MP) THA after a long follow-up time. METHODS: Standardized mortality ratios (SMR) of total and site-specific causes of death were calculated for 579 patients with MM (McKee-Farrar) and 1585 patients with MP (Brunswik, Lubinus) THA for primary osteoarthritis. RESULTS: Mean follow-up time was 17.9 years for patients with MM and 16.7 years for patients with MP. Overall SMR was 0.95 for the MM cohort and 0.90 for the MP cohort, as compared to the normal population. Both cohorts showed significantly decreased mortality for the first decade postoperatively, equal mortality over the next 10 years, and significantly increased mortality after 20 years. Patients with MM THA had higher cancer mortality (SMR 1.01) than those with MP THA (SMR 0.66) during the first 20 years postoperatively, but not thereafter. CONCLUSION: Both MM and MP prostheses are safe based on total and site-specific mortality of recipients during the first 20 postoperative years in comparison with the general population.

Cementless total hip arthroplasty for primary osteoarthritis in patients aged 55 years and older.

BACKGROUND: Cemented total hip arthroplasty has been the treatment of choice for elderly patients with osteoarthritis. We analyzed survival rates of the most common cementless designs used in this age group in Finland. PATIENTS AND METHODS: Inclusion criteria permitted 10,310 replacements (8 designs) performed in patients aged 55 years or older to be selected for evaluation. The risk of revision of each of the 8 implants was compared with that of a group comprising 3 cemented designs as the reference (9,549 replacements). Survival analyses were performed overall and separately for 3 age cohorts: 55-64 years (6,781 replacements), 65-74 years (8,821 replacements), and 75 years or older (4,257 replacements). RESULTS: In all patients aged 55 years or more, the Bi-Metric stem had a higher survival rate for aseptic loosening at 15 years than the cemented reference group: 96% (95% CI: 94-98) vs. 91% (CI: 90-92). However, the 15-year survival rates of the Bi-Metric/Press-Fit Universal (71% (CI: 67-75)) and the Anatomic Mesh/Harris-Galante II (72% (CI: 67-78)) total hip replacements were lower than that of the reference group (86% (CI: 84-87)). Information was scarce for patients aged 75 years or more. INTERPRETATION: Cementless proximal porous-coated stems are a good option for elderly patients. Even though biological fixation is a reliable fixation method in THA, polyethylene wear and osteolysis remain a serious problem for cementless cup designs with unplugged screw holes and low-quality liners.

Total ankle replacement: a population-based study of 515 cases from the Finnish Arthroplasty Register.

BACKGROUND AND PURPOSE: Although total ankle replacement (TAR) is a recognized procedure for treatment of the painful arthritic ankle, the best choice of implant and the long-term results are still unknown. We evaluated the survival of two TAR designs and factors associated with survival using data from the nationwide arthroplasty registry in Finland. METHODS: 573 primary TARs were performed during the period 1982-2006 because of rheumatic, arthritic, or posttraumatic ankle degeneration. We selected contemporary TAR designs that were each used in more than 40 operations, including the S.T.A.R. (n = 217) and AES (n = 298), to assess their respective survival rates. The mean age of the patients was 55 (17-86) years and 63% of operations were performed in women. Kaplan-Meier analysis and the Cox regression model were used for survival analysis. The effects of age, sex, diagnosis, and hospital volume were also studied. RESULTS: The annual incidence of TAR was 1.5 per 10(5) inhabitants. The 5-year overall survivorship for the whole TAR cohort was 83% (95% CI: 81-86), which agrees with earlier reports. The most frequent reasons for revision were aseptic loosening of one or both of the prosthesis components (39%) and instability (39%). We found no difference in survival rate between the S.T.A.R. and AES designs. Furthermore, age, sex, diagnosis, and hospital volume (< 10 and > 100 replacements in each of 17 hospitals) did not affect the TAR survival. INTERPRETATION: Based on our findings, we cannot conclude that any prosthesis was superior to any other. A high number of technical errors in primary TARs suggests that this low-volume field of implant arthroplasty should be centralized to fewer units.

Cancer risk is not increased after conventional hip arthroplasty.

BACKGROUND AND PURPOSE: Wear debris from conventional total hip arthroplasty (THA) induces chromosomal aberrations and DNA damage, which may promote cancerogenesis. A long latent period is required for solid tumors. We therefore re-analyzed a large THA cohort for cancer. PATIENTS AND METHODS: We updated a cohort of 24,636 patients with primary osteoarthritis and metal-on-polyethylene THA who had been entered in the Finnish Arthroplasty Register between 1980 and 1995, and linked it to the Finnish Cancer Registry for cancer risk assessment up to 2005. The mean follow-up time was 13 years. The numbers of cancer cases observed were compared with expected rates based on incidence in the general population. RESULTS: The standardized incidence ratio (SIR) for the whole follow-up period was 0.95 (95% confidence interval (CI): 0.92-0.97). After 10 years of follow-up, the SIR was equal to that in the normal population (SIR = 0.98, 95% CI: 0.94-1.03). Incidence of lung cancer was low throughout the follow-up time and that of prostate cancer was slightly elevated. The incidence rates for all other forms of cancer did not deviate significantly from those in the normal population. INTERPRETATION: We found no increased cancer risk in patients with conventional THA after an average of 13 years and up to 25 years of follow-up.

Total elbow arthroplasty in rheumatoid arthritis: a population-based study from the Finnish Arthroplasty Register.

BACKGROUND AND PURPOSE: Although total elbow arthroplasty (TEA) is a recognized procedure for the treatment of the painful arthritic elbow, the choice of implant is still obscure. We evaluated the survival of different TEA designs and factors associated with survival using data from a nationwide arthroplasty register. METHODS: 1,457 primary TEAs for rheumatoid elbow destruction were performed during 1982 to 2006 in one hospital specialized in the treatment of rheumatoid arthritis (n = 776) and in 19 other hospitals (n = 681). The mean age of the patients was 59 years and 87% of the TEAs were performed in women. We selected different contemporary TEA designs, each used in more than 40 operations including the Souter-Strathclyde (n = 912), i.B.P./Kudo (n = 218), Coonrad-Morrey (n = 164), and NESimplavit/Norway (n = 63) to assess their individual survival rates. Kaplan-Meier analysis and the Cox regression model were used for survival analysis. RESULTS: The most frequent reason for revision was aseptic loosening (47%). We found no differences in survival rates between different TEA designs. We did, however, find a 1.5-fold (95% CI: 1.1-2.1) elevated risk of revision in unspecialized hospitals as compared to the one hospital specialized in treatment of rheumatoid arthritis. In the Souter-Strathclyde subgroup, there was a reduced risk of revision (RR 0.6, p = 0.001) in TEAs implanted over 1994-2006 as compared to those implanted earlier (1982-1993). The 10-year survivorship for the whole TEA cohort was 83% (95% CI: 81-86), which agrees with earlier reports. INTERPRETATION: The influence of implant choice on the survival of TEA is minor compared to hip and knee arthroplasties. Inferior survival rates of the TEAs performed in the unspecialized hospitals demonstrates the importance of proper indications, surgical technique, and postoperative follow-up, and endorses the need for centralization of these operations at specialized units.

The effect of waiting time on health-related quality of life, pain, and physical function in patients awaiting primary total hip replacement: a randomized controlled trial.

OBJECTIVE: This prospective randomized study assessed the effect of waiting time (WT) on health outcomes in Finnish patients admitted to hospital for primary total hip replacement (THR). METHODS: A total of 395 consecutive patients with a need for a primary THR because of osteoarthritis and who were placed on the waiting list between August 2002 and November 2003. After placement on the waiting list, the patients were randomly assigned to a short WT (

Medial unicompartmental knee arthroplasty with Miller-Galante II prosthesis: mid-term clinical and radiographic results.

AIM: The purpose of our study was to evaluate retrospectively the mid-term results of the Miller-Galante II (Zimmer, Warsaw, USA) unicondylar knee arthoplasty (UKA). METHOD: The study included 46 patients with medial UKAs. Mean follow-up time was 7.0 years (range 2.7-13.1 years). RESULTS: Survival rate of the prosthesis was 86.6% (95% CI 73.7-99.6) at 7 years. The mean clinical and functional Knee Society Scores had increased from 51 and 62 points preoperatively to 76 and 93 points (P < 0.001) postoperatively. Five of the 46 knees were revised because of excessive wear of the polyethylene liner, and three due to progression of the osteoarthritis in the lateral compartment of the knee. CONCLUSION: Survival of this fixed-bearing UKA was not as good as previously reported and polyethylene wear seems to be a more common problem than previously assumed.

Total hip arthroplasty for primary osteoarthritis in patients fifty-five years of age or older. An analysis of the Finnish arthroplasty registry.

BACKGROUND: According to the long-term results obtained from the Scandinavian arthroplasty registries, cemented total hip replacement has been the treatment of choice for osteoarthritis of the hip in elderly patients. The aim of the present study was to analyze population-based survival rates of the cemented and cementless total hip replacements performed for primary osteoarthritis in patients fifty-five years of age or older in Finland. METHODS: From 1980 to 2004, a total of 50,968 primary total hip replacements that met our criteria were entered in the Finnish Arthroplasty Registry. The success rate of different implant groups was analyzed. The implants included were classified in one of the following four groups: implants with a cementless, straight, proximally circumferentially porous-coated stem and a modular, porous-coated press-fit cup (cementless group 1); implants with a cementless, anatomic, proximally circumferentially porous-coated and/or hydroxyapatite-coated stem with a modular, porous-coated and/or hydroxyapatite-coated press-fit cup (cementless group 2); a hybrid total hip replacement consisting of a cemented stem combined with a modular, press-fit cup (the hybrid group); and a cemented loaded-taper or composite-beam stem combined with an all-polyethylene cup (the cemented group). RESULTS: Cementless total hip replacements, as well as cementless stems and cups analyzed separately, had a significantly reduced risk of revision for aseptic loosening compared with cemented hip replacements (p < 0.001). When revision for any reason was the end point in survival analyses, however, there were no significant differences among the groups. In patients between the ages of fifty-five and sixty-four years, the fifteen-year survival rates of the two cementless groups (78% and 80%) were higher than that of the cemented group (71%) with revision for aseptic loosening as the end point. In patients who were sixty-five to seventy-four years old, the fifteen-year survival rate of the implants in cementless group 1 was 94%, while cemented total hip replacements had an 85% survival rate. In patients who were seventy-five years old or more, no significant differences were detected among the total hip replacement groups; all of them had survivorship of >90% at ten years. CONCLUSIONS: In patients who were fifty-five years of age or older, the long-term survival of cementless total hip replacements was comparable with that of cemented replacements. In patients who were fifty-five to seventy-four years old, straight porous-coated cementless stems had better long-term survival than the cemented stems. In patients who were seventy-five years of age and older, there were no significant differences in the results. Multiple wear-related revisions of the cementless cups in the present study indicate that excessive polyethylene wear was a major clinical problem with modular cementless cups in all age groups. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Comparison of survival and cost-effectiveness between unicondylar arthroplasty and total knee arthroplasty in patients with primary osteoarthritis: a follow-up study of 50,493 knee replacements from the Finnish Arthroplasty Register.

BACKGROUND AND PURPOSE: Both unicondylar arthroplasty (UKA) and total knee arthroplasty (TKA) are commonly used for the treatment of unicompartmental osteoarthritis (OA) of the knee. The long-term survivorship and cost-effectiveness of these two treatments have seldom been compared on a nationwide level, however. We therefore compared the survival of UKA with that of TKA and conducted a cost-benefit analysis comparing UKA with TKA in patients with primary OA. PATIENTS AND METHODS: We analyzed 1,886 primary UKAs (3 designs) and 48,607 primary TKAs that had been performed for primary OA and entered in the Finnish Arthroplasty Register between 1980 and 2003 inclusive. RESULTS: UKAs had a 60% (95% CI: 54-66) survival rate and TKAs an 80% (95% CI: 79-81) survival rate at 15 years with any revision taken as the endpoint. Overall survival of UKAs was worse than that of TKAs (p < 0.001). All 3 UKA designs had poorer overall survival than the corresponding TKA designs. In the theoretical cost-benefit analysis, the cost saved by lower implant prices and shorter hospital stay with UKA did not cover the costs of the extra revisions. INTERPRETATION: At a nationwide level, UKA had significantly poorer long-term survival than TKA. What is more, UKA did not even have a theoretical cost benefit over TKA in our study. Based on these results, we cannot recommend widespread use of UKA in treatment of unicompartmental OA of the knee.

Is longer waiting time associated with health and social services utilization before treatment? A randomized study.

OBJECTIVE: To determine whether longer waiting time for major joint replacement is associated with health and social services utilization before treatment. METHODS: When placed on the waiting list, patients were randomized to short (

Evaluating waiting time effect on health outcomes at admission: a prospective randomized study on patients with osteoarthritis of the knee joint.

AIMS: To evaluate the effect of waiting on health-related quality of life (HRQoL), pain and physical function in patients awaiting primary total knee replacement (TKR) due to osteoarthritis. METHODS: Some 438 patients awaiting TKR were randomized to a short waiting time (WT) group (< or =3 months) or a non-fixed WT group. In the final assessment, 310 patients (213 women) with a mean age of 68 years were included. HRQoL was measured on being placed on the waiting list and again at hospital admission using the generic 15D. Patients' self-report pain and physical function were evaluated using a scale modified from the Knee Society Clinical Rating System. RESULTS: The median WTs for patients with short and non-fixed WT were 73 days (range 8-600 days) and 266 days (range 28-818 days), respectively. At admission, as assessed by the intention-to-treat analysis, there were no statistically significant differences between the groups in the 15D total score and disease-specific pain and function. CONCLUSIONS: Our study showed that longer WT did not result in worse pre-operative HRQoL.

Effectiveness of hip or knee replacement surgery in terms of quality-adjusted life years and costs.

BACKGROUND: Concurrent head-to-head comparisons of healthcare interventions regarding cost-utility are rare. The concept of favorable cost-effectiveness of total hip or knee arthroplasty is thus inadequately verified. PATIENTS AND METHODS: In a trial involving several thousand patients from 10 medical specialties, 223 patients who were enrolled for hip or knee replacement surgery were asked to fill in the 15D health-related quality of life (HRQoL) survey before and after operation. RESULTS: Mean (SD) HRQoL score (on a 0-1 scale) increased in primary hip replacement patients (n = 96) from 0.81 (0.084) preoperatively to 0.86 (0.12) at 12 months (p < 0.001). In revision hip replacement (n = 24) the corresponding scores were 0.81 (0.086) and 0.82 (0.097) respectively (p = 0.4), and in knee replacement (n = 103) the scores were 0.81 (0.093) and 0.84 (0.11) respectively (p < 0.001). Of 15 health dimensions, there were statistically significant improvements in moving, usual activities, discomfort and symptoms, distress, and vitality in both primary replacement groups. Mean cost per quality-adjusted life year (QALY) gained during a 1-year period was euro 6,710 for primary hip replacement, euro 52,274 for revision hip replacement, and euro 13,995 for primary knee replacement. INTERPRETATION: Hip and knee replacement both improve HRQoL. The cost per QALY gained from knee replacement is twice that gained from hip replacement.