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

BACKGROUND: Concerns have been raised that implants used in total hip replacements (THR) could lead to increased cancer risk. Several different materials, metals and fixation techniques are used in joint prostheses and different types of articulation can cause an increased invasion of particles or ions into the human body. METHODS: Patients with THR registered in the Norwegian Arthroplasty Register during 1987-2009 were linked to the Cancer registry of Norway. Patients with THR due to osteoarthritis, under the age of 75 at time of surgery, were included. Standardized incidence ratios (SIR) were applied to compare cancer risk for THR patients to the general population. Types of THR were divided into cemented (both components), uncemented (both components), and hybrid (cemented femoral and uncemented acetabular components). To account for selection mechanisms, time dependent covariates were applied in Cox-regression, adjusting for cancer risk the first 10 years after surgery. The analyses were adjusted for age, gender and if the patient had additional THR-surgery in the same or the opposite hip. The study follows the STROBE guidelines. RESULTS: Comparing patients with THR to the general population in Norway we found no differences in cancer risk. The overall SIR for the THR-patients after 10 years follow-up was 1.02 (95% CI: 0.97-1.07). For cemented THR, the SIR after 10 years follow-up was 0.99 (95% CI: 0.94-1.05), for uncemented, 1.16 (95% CI: 1.02-1.30), and for hybrid 1.12 (95% CI: 0.91-1.33). Adjusted Cox analyses showed that patients with uncemented THRs had an elevated risk for cancer (hazard ratio: HR = 1.24, 95% CI: 1.05-1.46, p = 0.009) when compared to patients with cemented THRs after 10 years follow-up. Stratified by gender the increased risk was only present for men. The risk for patients with hybrid THRs was not significantly increased (HR = 1.07, 95% CI: 0.85-1.35, p = 0.55) compared to patients with cemented THRs. CONCLUSIONS: THR patients had no increased risk for cancer compared to the general population. We found, however, that receiving an uncemented THR was associated with a small increased risk for cancer compared to cemented THR in males, but that this may be prone to unmeasured confounding.

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

BACKGROUND: The aim of this study was to assess which patient and procedure factors affected both the risk of infection as well as procedure duration. Additionally, to assess if procedure duration affected the revision risk due to deep infection in total knee arthroplasty (TKA) patients and in a subgroup of low-risk patients. METHODS: 28,262 primary TKA with 311 revisions due to deep infection were included from the Norwegian Arthroplasty Register (NAR) and analysed from primary surgery from 2005 until 31st December 2015 with a 1 and 4 year follow up. The risk of revision due to deep infection was calculated in a multivariable Cox regression model including patient and procedure related risk factors, assessing Hazard Ratio (HR) with 95% confidence interval (CI). RESULTS: Multivariate analysis showed statistically significant associations with revision due to deep infection and increased procedure duration for male patients, ASA3+ (American Society of Anesthesiologists) and perioperative complications. Procedure duration ≥110 min (75 percentile) had a higher risk of deep infection compared to duration <75 min (25 percentile), in the unadjusted analysis (HR = 1.8, 95% CI 1.3-2.5, p = 0.001) and in the adjusted analysis (HR = 1.5, 95% CI 1.0-2.1, p = 0.03). For low-risk patients, procedure duration did not increase the risk of infection. CONCLUSION: Male patients, ASA 3+ patients and perioperative complications were risk factors both for longer procedure duration and for deep infection revisions. Patients with a high degree of comorbidity, defined as ASA3+, are at risk of infection with longer procedure durations. The occurrence of perioperative complications potentially leading to a more complex and lengthy procedure was associated with a higher risk of infection. Long procedure duration in itself seems to have minor impact on infection since we found no association in the low-risk patient.

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

BACKGROUND: High procedure volume and dedication to unicompartmental knee arthroplasty (UKA) has been suggested to improve revision rates. This study aimed to quantify the annual hospital volume effect on revision risk in Oxfordu nicompartmental knee arthroplasty in the Nordic countries. METHODS: 14,496 cases of cemented medial Oxford III UKA were identified in 126 hospitals in the four countries included in the Nordic Arthroplasty Register Association (NARA) database from 2000 to 2012. Hospitals were divided by quartiles into 4 annual procedure volume groups (≤11, 12-23, 24-43 and ≥44). The outcome was revision risk after 2 and 10 years calculated using Kaplan Meier method. Multivariate Cox regression analysis was used to assess the Hazard Ratio (HR) of any revision due to specific reasons with 95% confidence intervals (CI). RESULTS: The implant survival was 80% at 10 years in the volume group ≤11 procedures per year compared to 83% in other volume groups. The HR adjusted for age category, sex, year of surgery and nation was 0.87 (95% CI: 0.76-0.99, p = 0.036) for the group 12-23 procedures per year, 0.78 (95% CI: 0.68-0.91, p = 0.002) for the group 24-43 procedures per year and 0.82 (95% CI: 0.70-0.94, p = 0.006) for the group ≥44 procedures per year compared to the low volume group. Log-rank test was p = 0.003. The risk of revision for unexplained pain was 40-50% higher in the low compared with other volume groups. CONCLUSION: Low volume hospitals performing ≤11 Oxford III UKAs per year were associated with an increased risk of revision compared to higher volume hospitals, and unexplained pain as revision cause was more common in low volume hospitals.

Bone cement product and failure in total knee arthroplasty.

Background and purpose - The bone cement market for total knee arthroplasty (TKA) in Norway has been dominated by a few products and distributors. Palacos with gentamicin had a market share exceeding 90% before 2005, but it was then withdrawn from the market and replaced by new slightly altered products. We have compared the survival of TKAs fixated with Palacos with gentamicin with the survival of TKAs fixated with the bone cements that took over the market. Patients and methods - Using data from the Norwegian Arthroplasty Register for the period 1997-2013, we included 26,147 primary TKAs in the study. The inclusion criteria were TKAs fixated with the 5 most used bone cements and the 5 most common total knee prostheses for that time period. 6-year Kaplan-Meier survival probabilities were established for each cement product. The Cox proportional hazards regression model was used to assess the association between bone cement product and revision risk. Separate analyses were performed with revision for any reason and revision due to deep infection within 1 year postoperatively as endpoints. Adjustments were made for age, sex, diagnosis, and prosthesis brand. Results - Survival was similar for the prostheses in the follow-up period, between the 5 bone cements included: Palacos with gentamicin, Refobacin Palacos R, Refobacin Bone Cement R (Refobacin BCR), Optipac Refobacin Bone Cement R (Optipac Refobacin BCR), and Palacos R + G. Interpretation - According to our findings, the use of the new bone cements led to a survival rate that was as good as with the old bone cement (Palacos with gentamicin).

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

Background and purpose - Hemiarthroplasty (HA) is the most common treatment for displaced femoral neck fractures in many countries. In Norway, there has been a tradition of using the direct lateral surgical approach, but worldwide a posterior approach is more often used. Based on data from the Norwegian Hip Fracture Register, we compared the results of HA operated through the posterior and direct lateral approaches regarding patient-reported outcome measures (PROMs) and reoperation rate. Patients and methods - HAs due to femoral neck fracture in patients aged 60 years and older were included from the Norwegian Hip Fracture Register (2005-2014). 18,918 procedures were reported with direct lateral approach and 1,990 with posterior approach. PROM data (satisfaction, pain, quality of life (EQ-5D), and walking ability) were reported 4, 12, and 36 months postoperatively. The Cox regression model was used to calculate relative risk (RR) of reoperation. Results - There were statistically significant differences in PROM data with less pain, better satisfaction, and better quality of life after surgery using the posterior approach than using the direct lateral approach. The risk of reoperation was similar between the approaches. Interpretation - Hemiarthroplasty for hip fracture performed through a posterior approach rather than a direct lateral approach results in less pain, with better patient satisfaction and better quality of life. The risk of reoperation was similar with both approaches.

Improved outcome after hip fracture surgery in Norway.

Background and purpose - The operative treatment of hip fractures in Norway has changed considerably during the last decade. We used data in the Norwegian Hip Fracture Register to investigate possible effects of these changes on reoperations and 1-year mortality. Patients and methods - 72,741 femoral neck (FFN) fractures and trochanteric fractures in patients 60 years or older were analyzed. The fractures were divided into 5 time periods (2005-2006, 2007-2008, 2009-2010, 2011-2012, 2013-2014). Cox regression models were used to calculate unadjusted and adjusted (age group, sex, and ASA class) relative risks (RRs) of reoperation and of 1-year mortality in the different time periods. Results - For undisplaced FFNs treatment with hemiarthroplasty increased from 2.1% to 9.7% during the study period. For displaced FFNs treatment with arthroplasty increased from 56% to 93%. The use of intramedullary nails increased from 9.1% to 26% for stable 2-fragment (AO/OTA A1) trochanteric fractures, from 15% to 33% for multifragment (AO/OTA A2) trochanteric fractures, and from 27% to 61% for intertrochanteric fractures (AO/OTA A3)/subtrochanteric fractures. Compared with the first time period the adjusted 1-year RR for reoperation was 0.43 (95% CI: 0.37-0.49) for displaced FFNs in the last time period. The adjusted 1-year mortality in the last time period was lower for all fractures (RR: 0.87 (0.83-0.91)), displaced FFNs (RR: 0.86 (0.80-0.93)), AO/OTA A1 trochanteric fractures (RR: 0.79 (0.71-0.88)), and AO/OTA A2 trochanteric fractures (RR: 0.87 (0.77-0.98)) when compared with the first study period. Interpretation - Hip fracture treatment in Norway has improved: The risk of reoperation and the 1-year mortality after displaced femoral neck fractures have decreased over a 10-year period. National registration is useful to monitor trends in treatment and outcomes after hip fractures.

Reverse hybrid total hip arthroplasty.

Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty Register Association (NARA) has already published 2 papers describing results of reverse hybrid THAs in different age groups. Based on data collected over 2 additional years, we wanted to perform in depth analyses of not only the reverse hybrid concept but also of the different cup/stem combinations used. Patients and methods - From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk of revision. The main endpoint was revision for any reason. We also performed specific analyses regarding the different reasons for revision and analyses regarding the cup/stem combinations used in more than 500 cases. Results - We found a higher rate of revision for reverse hybrids than for cemented THAs, with an adjusted relative risk of revision (RR) of 1.4 (95% CI: 1.3-1.5). At 10 years, the survival rate was 94% (CI: 94-95) for cemented THAs and 92% (95% CI: 92-93) for reverse hybrids. The results for the reverse hybrid THAs were inferior to those for cemented THAs in patients aged 55 years or more (RR =1.1, CI: 1.0-1.3; p < 0.05). We found a higher rate of early revision due to periprosthetic femoral fracture for reverse hybrids than for cemented THAs in patients aged 55 years or more (RR =3.1, CI: 2.2-4.5; p < 0.001). Interpretation - Reverse hybrid THAs had a slightly higher rate of revision than cemented THAs in patients aged 55 or more. The difference in survival was mainly caused by a higher incidence of early revision due to periprosthetic femoral fracture in the reversed hybrid THAs.

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

BACKGROUND AND PURPOSE: Previous studies have found different outcomes after revision of knee arthroplasties performed after high tibial osteotomy (HTO). We evaluated the risk of revision of total knee arthroplasty with or without previous HTO in a large registry material. PATIENTS AND METHODS: 31,077 primary TKAs were compared with 1,399 TKAs after HTO, using Kaplan-Meier 10-year survival percentages and adjusted Cox regression analysis. RESULTS: The adjusted survival analyses showed similar survival in the 2 groups. The Kaplan-Meier 10-year survival was 93.8% in the primary TKA group and 92.6% in the TKA-post-HTO group. Adjusted RR was 0.97 (95% CI: 0.77-1.21; p = 0.8). INTERPRETATION: In this registry-based study, previous high tibial osteotomy did not appear to compromise the results regarding risk of revision after total knee arthroplasty compared to primary knee arthroplasty.

Improved survival for anatomic total shoulder prostheses.

BACKGROUND AND PURPOSE: Previously, implant survival of total shoulder prostheses was reported to be inferior to that of hemiprostheses. However, the use of total prostheses has increased in Norway due to reported good functional results. On this background, we wanted to study implant survival of 4 major shoulder prosthesis types in Norway between 1994 and 2012. PATIENTS AND METHODS: The study population comprised 4,173 patients with shoulder replacements reported to the Norwegian Arthroplasty Register, including 2,447 hemiprostheses (HPs), 444 anatomic total prostheses (ATPs), 454 resurfacing prostheses (RPs), and 828 reversed total prostheses (RTPs). Three time periods were compared: 1994-1999, 2000-2005, and 2006-2012. Kaplan-Meier failure curves were used to compare implant failure rates for subgroups of patients, and adjusted risks of revision were calculated using Cox regression analysis. RESULTS: For prostheses inserted from 2006 through 2012, the 5-year survival rates were 95% for HPs (as opposed to 94% in 1994-1999), 95% for ATPs (75% in 1994-1999), 87% for RPs (96% in 1994-1999), and 93% for RTPs (91% in 1994-1999). During the study period, the implant survival improved significantly for ATPs (p < 0.001). A tendency of better results with acute fracture and worse results in sequelae after previous fractures was seen in all time periods. INTERPRETATION: The 5-year implant survival rates were good with all prosthesis types, and markedly improved for anatomic total prostheses in the last 2 study periods. The better functional results with total shoulder prostheses than with hemiprostheses support the trend towards increased use of total shoulder prostheses.

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

BACKGROUND AND PURPOSE: Some studies have found high complication rates and others have found low complication rates after unicompartmental knee arthroplasty (UKA). We evaluated whether hospital procedure volume influences the risk of revision using data from the Norwegian Arthroplasty Register (NAR). MATERIALS AND METHODS: 5,791 UKAs have been registered in the Norwegian Arthroplasty Register. We analyzed the 4,460 cemented medial Oxford III implants that were used from 1999 to 2012; this is the most commonly used UKA implant in Norway. Cox regression (adjusted for age, sex, and diagnosis) was used to estimate risk ratios (RRs) for revision. 4 different volume groups were compared: 1-10, 11-20, 21-40, and > 40 UKA procedures annually per hospital. We also analyzed the reasons for revision. RESULTS AND INTERPRETATION: We found a lower risk of revision in hospitals performing more than 40 procedures a year than in those with less than 10 UKAs a year, with an unadjusted RR of 0.53 (95% CI: 0.35-0.81) and adjusted RR of 0.59 (95% CI: 0.39-0.90). Low-volume hospitals appeared to have a higher risk of revision due to dislocation, instability, malalignment, and fracture than high-volume hospitals.

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

BACKGROUND: The surgical approach in total hip arthroplasty (THA) is often based on surgeon preference and local traditions. The anterior muscle-sparing approach has recently gained popularity in Europe. We tested the hypothesis that patient satisfaction, pain, function, and health-related quality of life (HRQoL) after THA is not related to the surgical approach. PATIENTS: 1,476 patients identified through the Norwegian Arthroplasty Register were sent questionnaires 1-3 years after undergoing THA in the period from January 2008 to June 2010. Patient-reported outcome measures (PROMs) included the hip disability osteoarthritis outcome score (HOOS), the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), health-related quality of life (EQ-5D-3L), visual analog scales (VAS) addressing pain and satisfaction, and questions about complications. 1,273 patients completed the questionnaires and were included in the analysis. RESULTS: Adjusted HOOS scores for pain, other symptoms, activities of daily living (ADL), sport/recreation, and quality of life were significantly worse (p < 0.001 to p = 0.03) for the lateral approach than for the anterior approach and the posterolateral approach (mean differences: 3.2-5.0). These results were related to more patient-reported limping with the lateral approach than with the anterior and posterolateral approaches (25% vs. 12% and 13%, respectively; p < 0.001). INTERPRETATION: Patients operated with the lateral approach reported worse outcomes 1-3 years after THA surgery. Self-reported limping occurred twice as often in patients who underwent THA with a lateral approach than in those who underwent THA with an anterior or posterolateral approach. There were no significant differences in patient-reported outcomes after THA between those who underwent THA with a posterolateral approach and those who underwent THA with an anterior approach.

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

BACKGROUND AND PURPOSE: Previous studies of patients who have undergone total hip arthroplasty (THA) due to femoral head necrosis (FHN) have shown an increased risk of revision compared to cases with primary osteoarthritis (POA), but recent studies have suggested that this procedure is not associated with poor outcome. We compared the risk of revision after operation with THA due to FHN or POA in the Nordic Arthroplasty Register Association (NARA) database including Denmark, Finland, Norway, and Sweden. PATIENTS AND METHODS: 427,806 THAs performed between 1995 and 2011 were included. The relative risk of revision for any reason, for aseptic loosening, dislocation, deep infection, and periprosthetic fracture was studied before and after adjustment for covariates using Cox regression models. RESULTS: 416,217 hips with POA (mean age 69 (SD 10), 59% females) and 11,589 with FHN (mean age 65 (SD 16), 58% females) were registered. The mean follow-up was 6.3 (SD 4.3) years. After 2 years of observation, 1.7% in the POA group and 3.0% in the FHN group had been revised. The corresponding proportions after 16 years of observation were 4.2% and 6.1%, respectively. The 16-year survival in the 2 groups was 86% (95% CI: 86-86) and 77% (CI: 74-80). After adjusting for covariates, the relative risk (RR) of revision for any reason was higher in patients with FHN for both periods studied (up to 2 years: RR = 1.44, 95% CI: 1.34-1.54; p < 0.001; and 2-16 years: RR = 1.25, 1.14-1.38; p < 0.001). INTERPRETATION: Patients with FHN had an overall increased risk of revision. This increased risk persisted over the entire period of observation and covered more or less all of the 4 most common reasons for revision.

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

BACKGROUND AND PURPOSE: An earlier Nordic Arthroplasty Register Association (NARA) report on 280,201 total hip replacements (THRs) based on data from 1995-2006, from Sweden, Norway, and Denmark, was published in 2009. The present study assessed THR survival according to country, based on the NARA database with the Finnish data included. MATERIAL AND METHODS: 438,733 THRs performed during the period 1995-2011 in Sweden, Denmark, Norway, and Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities with 95% confidence interval (CI). Cox multiple regression, with adjustment for age, sex, and diagnosis, was used to analyze implant survival with revision for any reason as endpoint. RESULTS: The 15-year survival, with any revision as an endpoint, for all THRs was 86% (CI: 85.7-86.9) in Denmark, 88% (CI: 87.6-88.3) in Sweden, 87% (CI: 86.4-87.4) in Norway, and 84% (CI: 82.9-84.1) in Finland. Revision risk for all THRs was less in Sweden than in the 3 other countries during the first 5 years. However, revision risk for uncemented THR was less in Denmark than in Sweden during the sixth (HR = 0.53, CI: 0.34-0.82), seventh (HR = 0.60, CI: 0.37-0.97), and ninth (HR = 0.59, CI: 0.36-0.98) year of follow-up. INTERPRETATION: The differences in THR survival rates were considerable, with inferior results in Finland. Brand-level comparison of THRs in Nordic countries will be required.

Risk factors for infection after 46,113 intramedullary nail operations in low- and middle-income countries.

BACKGROUND: The fields of surgery and trauma care have largely been neglected in the global health discussion. As a result the idea that surgery is not safe or cost effective in resource-limited settings has gone unchallenged. The SIGN Online Surgical Database (SOSD) is now one of the largest databases on trauma surgery in low- and middle-income countries (LMIC). We wished to examine infection rates and risk factors for infection after IM nail operations in LMIC using this data. METHODS: The SOSD contained 46,722 IM nail surgeries in 58 different LMIC; 46,113 IM nail operations were included for analysis. RESULTS: The overall follow-up rate was 23.1 %. The overall infection rate was 1.0 %, 0.7 % for humerus, 0.8 % for femur, and 1.5 % for tibia fractures. If only nails with registered follow-up (n = 10,684) were included in analyses, infection rates were 2.9 % for humerus, 3.2 % for femur, and 6.9 % for tibia fractures. Prophylactic antibiotics reduced the risk of infection by 29 %. Operations for non-union had a doubled risk of infection. Risk of infection was reduced with increasing income level of the country. CONCLUSIONS: The overall infection rates were low, and well within acceptable levels, suggesting that it is safe to do IM nailing in low-income countries. The fact that operations for non-union have twice the risk of infection compared to primary fracture surgery further supports the use of IM nailing as the primary treatment for femur fractures in LMIC.

Pain and function in eight hundred and fifty nine patients comparing shoulder hemiprostheses, resurfacing prostheses, reversed total and conventional total prostheses.

PURPOSE: Functional results of reversed total prostheses (RTP) have-to a very limited degree-been compared with those of other shoulder prosthesis types. The aim of our study was to compare results of four different types of shoulder prostheses in terms of function, pain, and quality of life (QoL). METHODS: Questionnaires were completed by 859 patients with shoulder prostheses registered in the Norwegian Arthroplasty Register. Patients with osteoarthritis (OA), rheumatoid arthritis (RA), or fracture sequela (FS) were included. Symptoms and function were assessed using the Oxford Shoulder Score (OSS, scale 0-48), and the EuroQoL-5D (EQ-5D) was used to assess QoL. RESULTS: Best functional results were obtained using conventional total prostheses (TPs) and RTPs -mean OSS improvement 18 and 16 units, respectively, vs 11 with hemiprostheses (HPs). For patients with OA, TPs performed best; for those with RA and FS, RTPs performed best; and those with HPs had the worst results in all diagnostic groups. The greatest improvement in QoL was seen in patients with TPs and RTPs. CONCLUSIONS: Conventional TPs provide the best improvement in pain, function and QoL in OA patients; RTPs are superior in patients with RA and FS.

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

BACKGROUND: Some surgeons believe that internal fixation of fractures carries too high a risk of infection in low-income countries (LICs) to merit its use there. However, there have been too few studies from LICs with sufficient follow-up to support this belief. We first wanted to determine whether complete follow-up could be achieved in an LIC, and secondly, we wanted to find the true microbial infection rate at our hospital and to examine the influence of HIV infection and lack of follow-up on outcomes. PATIENTS AND METHODS: 137 patients with 141 femoral fractures that were treated with intramedullary (IM) nailing were included. We compared outcomes in patients who returned for scheduled follow-up and patients who did not return but who could be contacted by phone or visited in their home village. RESULTS: 79 patients returned for follow-up as scheduled; 29 of the remaining patients were reached by phone or outreach visits, giving a total follow-up rate of 79%. 7 patients (5%) had a deep postoperative infection. All of them returned for scheduled follow-up. There were no infections in patients who did not return for follow-up, as compared to 8 of 83 nails in the group that did return as scheduled (p = 0.1). 2 deaths occurred in HIV-positive patients (2/23), while no HIV-negative patients (0/105) died less than 30 days after surgery (p = 0.03). INTERPRETATION: We found an acceptable infection rate. The risk of infection should not be used as an argument against IM nailing of femoral fractures in LICs. Many patients in Malawi did not return for follow-up because they had no complaints concerning the fracture. There was an increased postoperative mortality rate in HIV-positive patients.

Coordinating retrieval and register studies improves postmarket surveillance.

BACKGROUND: The relative risk of revision of the Titan(®) femoral stem due to aseptic loosening increased after 2000; however, the reasons for this have not been established. A retrieval analysis was initiated with the aim of delineating the failure mechanism. QUESTIONS/PURPOSES: We asked whether aseptic loosening in stems after 2000 was associated with (1) appearance of osteolytic lesions, (2) wear particle exposure, (3) stem damage, or (4) changes to the implant or surgical instrumentation. METHODS: Femoral stems, cement, tissue, and radiographs were collected from 28 patients. We assessed the development of osteolytic lesions in 17 patients. Exposure to wear particles was quantified in 18 patients. Stem damage was assessed in 15 patients. We observed differences in the implants by examination of 24 retrieved stems. Information concerning changes to instrumentation was requested from the manufacturer. RESULTS: We found osteolysis in all patients receiving implants after 2000, which was associated with a median dose of cement and stem particles of 14,726/mm(2). Abrasion covered 59% of the surface of stems implanted from 1999. We identified geometric changes to the stem, the percent weight of aluminum in the stem's oxide layer decreased from 25% to 14% after 1997 and the rasp used to prepare the femoral cavity changed to a broach in 1999. CONCLUSIONS: Stems implanted from 2000 failed through osteolysis induced by particles released from the cement and implant. Changes to implant geometry, surface oxide layer, and surgical tools occurred in the same time frame as the reduction in survivorship.

Is there still a place for the cemented titanium femoral stem? 10,108 cases from the Norwegian Arthroplasty Register.

BACKGROUND AND PURPOSE: Despite the fact that there have been some reports on poor performance, titanium femoral stems intended for cemented fixation are still used at some centers in Europe. In this population-based registry study, we examined the results of the most frequently used cemented titanium stem in Norway. PATIENTS AND METHODS: 11,876 cases implanted with the cemented Titan stem were identified for the period 1987-2008. Hybrid arthroplasties were excluded, leaving 10,108 cases for this study. Stem survival and the influence of age, sex, stem offset and size, and femoral head size were evaluated using Cox regression analyses. Questionnaires were sent to the hospitals to determine the surgical technique used. RESULTS: Male sex, high stem offset, and small stem size were found to be risk factors for stem revision, (adjusted RR = 2.5 (1.9-3.4), 3.3 (2.3-4.8), and 2.2 (1.4-3.5), respectively). Patients operated in the period 2001-2008 had an adjusted relative risk (RR) of 4.7 (95% CI: 3.0-7.4) for stem revision due to aseptic stem loosening compared to the period 1996-2000. Changes in broaching technique and cementing technique coincided with deterioration of the results in some hospitals. INTERPRETATION: The increased use of small stem sizes and high-offset stems could only explain the deterioration of results to a certain degree since the year 2000. The influence of discrete changes in surgical technique over time could not be fully evaluated in this registry study. We suggest that this cemented titanium stem should be abandoned. The results of similar implants should be carefully evaluated.

Shoulder instability surgery in Norway: the first report from a multicenter register, with 1-year follow-up.

BACKGROUND AND PURPOSE: In January 2008, we established the Norwegian Register for Shoulder Instability Surgery. We report on the establishment, the baseline data, and the results at 1-year follow-up. METHODS: Primary and revision shoulder stabilization is reported by the surgeon on a 1-page paper form containing the patient's history of shoulder injury, clinical findings, and perioperative findings. The WOSI questionnaire for self-assessment of shoulder function is completed at baseline and at follow-up after 1, 2, and 5 years. To evaluate the completeness of registration, we compared our data with those in the Norwegian Patient Registry (NPR). RESULTS: The NPR reported 39 hospitals performing shoulder stabilizations. 20 of these started to report to our register during 2009, and 464 procedures (404 primary, 59 revisions) were included up to December 31, 2009, which represented 54% of the procedures reported to NPR. Of the 404 primary procedures, 83% were operations due to anterior instability, 10% were operations due to posterior instability, and 7% were operations due to multidirectional instability. Arthroscopic soft tissue techniques were used in 88% of the patients treated for primary anterior instability and open coracoid transfer was used in 10% of such patients. At 1-year follow-up of 213 patients, we found a statistically significantly improved WOSI score in all types of instability. 10% of the patients treated with arthroscopic anterior labral repair and 16% treated with arthroscopic posterior labral repair reported recurrent instability. No statistically significant difference in functional improvement or rate of recurrence was found between these groups. INTERPRETATION: The functional results are in accordance with those in previous studies. However, the incidence of recurrent instability 1 year after arthroscopic labral repair is higher than expected.

Low revision rate after total hip arthroplasty in patients with pediatric hip diseases.

BACKGROUND: The results of primary total hip arthroplasties (THAs) after pediatric hip diseases such as developmental dysplasia of the hip (DDH), slipped capital femoral epiphysis (SCFE), or Perthes' disease have been reported to be inferior to the results after primary osteoarthritis of the hip (OA). MATERIALS AND METHODS: We compared the survival of primary THAs performed during the period 1995-2009 due to previous DDH, SCFE, Perthes' disease, or primary OA, using merged individual-based data from the Danish, Norwegian, and Swedish arthroplasty registers, called the Nordic Arthroplasty Register Association (NARA). Cox multiple regression, with adjustment for age, sex, and type of fixation of the prosthesis was used to calculate the survival of the prostheses and the relative revision risks. RESULTS: 370,630 primary THAs were reported to these national registers for 1995-2009. Of these, 14,403 THAs (3.9%) were operated due to pediatric hip diseases (3.1% for Denmark, 8.8% for Norway, and 1.9% for Sweden) and 288,435 THAs (77.8%) were operated due to OA. Unadjusted 10-year Kaplan-Meier survival of THAs after pediatric hip diseases (94.7% survival) was inferior to that after OA (96.6% survival). Consequently, an increased risk of revision for hips with a previous pediatric hip disease was seen (risk ratio (RR) 1.4, 95% CI: 1.3-1.5). However, after adjustment for differences in sex and age of the patients, and in fixation of the prostheses, no difference in survival was found (93.6% after pediatric hip diseases and 93.8% after OA) (RR 1.0, CI: 1.0-1.1). Nevertheless, during the first 6 postoperative months more revisions were reported for THAs secondary to pediatric hip diseases (RR 1.2, CI: 1.0-1.5), mainly due to there being more revisions for dislocations (RR 1.8, CI: 1.4-2.3). Comparison between the different diagnosis groups showed that the overall risk of revision after DDH was higher than after OA (RR 1.1, CI: 1.0-1.2), whereas the combined group Perthes' disease/SCFE did not have a significantly different risk of revision to that of OA (RR 0.9, CI: 0.7-1.0), but had a lower risk than after DDH (RR 0.8, CI: 0.7-1.0). INTERPRETATION: After adjustment for differences in age, sex, and type of fixation of the prosthesis, no difference in risk of revision was found for primary THAs performed due to pediatric hip diseases and those performed due to primary OA.