Risk factors for knee replacement due to primary osteoarthritis, a population based, prospective cohort study of 315,495 individuals

Background: Osteoarthritis (OA) of the knee is a common and disabling condition. We wanted to investigate the modifiable risk factors Body Mass Index (BMI) and physical activity, using knee replacement (KR) as a marker for severely symptomatic disease, focusing on the interaction between these risk factors. Methods: 315,495 participants (mean age 43.0 years) from national health screenings were followed prospectively with respect to KR identified by linkage to the Norwegian Arthroplasty Register. Data were analysed by Cox proportional hazard regression. Results: During 12 years of follow up 1,323 individuals received KR for primary OA. There was a dose–response relationship between BMI and heavy labour, and later KR. Comparing the highest versus the lowest quarter of BMI, the relative risk was 6.2 (95% CI: 4.2-9.0) in men and 11.1 (95% CI: 7.8-15.6) in women. Men reporting intensive physical activity at work had a relative risk of 2.4 (95% CI: 1.8-3.2) versus men reporting sedentary activity at work, the corresponding figure in women being 2.3 (95% CI: 1.7-3.2). The effect of BMI and physical activity at work was additive. The heaviest men with the most strenuous work had a RR of 11.7 (95% CI: 5.9-23.1) compared to the ones with the lowest BMI and most sedentary work. For women the corresponding RR was 15.8 (95% CI: 8.2-30.3). There was no association between physical activity during leisure and KR. Conclusion: We found that a high BMI and intensive physical activity at work both contribute strongly to the risk of having a KR. As the two risk factors seem to act independently, people with strenuous physical work with a high BMI are at particularly high risk for severely disabling OA of the knee, and should be targeted with effective preventive measures.publishedVersio

Five-Year follow-up results of a rondomized controlled study comparing intramedullary nailing With plate fixation of completely displaced midshaft fractures of the clavicle in adults

Background: Surgical management of completely displaced midshaft fractures of the clavicle is becoming more frequent, although long-term follow-up with Level-I evidence is scarce. Plate fixation (PF) of comminuted fractures provides faster functional recovery than elastic stable intramedullary nailing (ESIN). The 12-month follow-up of this randomized controlled trial, published previously, found no clinical differences at that time on the group level, but subtle differences on the subgroup level indicated that the results after closed ESIN were better than those after open ESIN. The primary aim of the study reported here was to compare the long-term clinical outcomes and sequelae after open reduction with those after closed reduction and to help surgeons develop a treatment strategy of either PF or ESIN for selected patients. Methods: At a median follow-up of 66 months (range, 49 to 89 months), the 123 patients in the original study were invited to an online secure survey. We used the survey results to compare the PF and ESIN treatment arms and to perform predetermined subgroup analyses of closed compared with open ESIN in relation to Disabilities of the Arm, Shoulder and Hand (DASH) score, pain assessment, and implant removal. Results: The questionnaire was completed by 114 (93%) of the 123 patients. There were no differences between the 2 treatment arms with regard to the DASH score (ESIN, 3.1 +/- 7.0 and PF, 3.7 +/- 7.5; p = 0.9). The 27 patients who had been treated with closed ESIN had a significantly superior DASH score compared with the 27 patients who had been treated with open ESIN (closed, 0.7 +/- 1.4 and open, 5.2 +/- 8.9; p = 0.015) and compared with the patients who had been treated with PF (closed ESIN, 0.7 +/- 1.4 and PF, 3.9 +/- 7.5; p = 0.002). Patients who had been treated with closed ESIN also reported fewer sequelae than patients who had been treated with open ESIN or PF. Conclusions: The results of this study, combined with those of our prior 1-year follow-up of the same patients, indicate that it seems to be advantageous to perform closed ESIN. The long-term results after PF were similar to those after open ESIN, but PF resulted in faster functional recovery and fewer patients needing to have the implant removed. Therefore, if open reduction is necessary for a comminuted fracture, it seems that the advantages of the minimally invasive ESIN procedure are lost, and the surgeon should consider conversion to PF. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence

Leisure time physical activity and the risk of hip or knee replacement due to primary osteoarthritis: A population based cohort study (The HUNT Study)

Background The relationship between leisure time physical activity (LPA) and hip and knee OA and subsequent joint replacement has not yet been clearly defined. Some studies have found the risk of knee replacement (TKR) to increase with high levels of LPA, while others have found no overall relationship to either TKR or hip replacement (THR). The aim was to investigate the association between LPA and the risk of severe end-stage OA, defined as THR or TKR due to primary OA, in a large population-based cohort. Methods Participants in the Nord-Trøndelag Health Study (HUNT) were followed prospectively to identify THR and TKR using the Norwegian Arthroplasty Register. Self-reported LPA was classified as inactive, low, moderate or high. The Cox proportional hazards model was used to calculate hazard ratios (HRs) according to levels of LPA with adjustments for confounding variables. Analyses were performed by age (<45, 45–59 and ≥60 years) and sex. Results A total of 66 964 participants (mean age 46.8 years (SD 16.3) were included in the analyses. We identified 1636 THRs and 1016 TKRs due to primary OA during 17.0 years (median) of follow-up. High LPA was significantly associated with THR for women <45 years (HR 1.78, 95 % CI 1.08–2.94) and men between 45–59 years (HR 1.53, 95 % CI 1.10–2.13) at baseline. A significant trend was found only among women < 45 years at baseline (p = 0.02). We found that LPA was significantly associated with TKR for women only (HR 1.45, 95 % CI 1.03–2.04). No measures of LPA were associated with TKR for men. Conclusion In this population-based study, high level of LPA was associated with increased risk of THR where a significant trend of LPA was seen among women <45 years at baseline. For TKR, high LPA was associated with increased risk only in women. In contrast to previous studies, this study shows a possible association between high LPA and the risk of THR.publishedVersio

Biomechanical comparison of tension band wiring and plate fixation with locking screws in transverse olecranon fractures

Background: Tension band wiring (TBW) is the standard method for treating transverse olecranon fractures, but high rates of complications and reoperations have been reported. Plate fixation (PF) with locking screws has been introduced as an alternative method that may retain the fracture reduction better with a higher load to failure. Methods: Twenty paired cadaveric elbows were used. All soft tissues except for the triceps tendon were removed. A standardized transverse fracture was created, and each pair was allocated randomly to TBW or PF with locking screws. The triceps tendon was mounted to the materials testing machine with the elbow in 90° of flexion. Construct stiffness was compared 3 times. Then, the elbows underwent a chair lift-off test by loading the triceps tendon to 300 N for 500 cycles. Finally, a load-to-failure test was performed, and failure mechanism was recorded. Results: The construct stiffness of PF was higher in the first of 3 measurements. No difference was observed in the cyclic test or in load to failure. Hardware failure was the failure mechanism in 8 of 10 TBW constructs, and all failures occurred directly under the twists of the metal wire. Hardware failure was the cause of failure in only 1 elbow in the PF group (P < .01). Conclusion: There was no difference in fracture displacement following fixation with TBW and PF with locking screws in transverse olecranon fractures. However, assessment of the mode of hardware failure identified the metal cerclage twist as the weakest link in the TBW construct

Metabolic syndrome as a risk factor for total hip or knee replacement due to primary osteoarthritis: A prospective cohort study (the HUNT study and the Norwegian arthroplasty register)

Objective: Biochemical changes associated with obesity may accelerate osteoarthritis beyond the effect of mechanical factors. This study investigated whether metabolic syndrome and its components (visceral obesity, hypertension, dyslipidemia and insulin resistance) were risk factors for subsequent total hip replacement (THR) or total knee replacement (TKR) due to primary osteoarthritis. Design: In this prospective cohort study, data from the second survey of the Nord-Trøndelag Health Study 2 (HUNT2) were linked to the Norwegian Arthroplasty Register for identification of the outcome of THR or TKR. The analyses were stratified by age (<50, 50–69.9 and ≥70 years) and adjusted for gender, body mass index, smoking, physical activity and education. Results: Of the 62,661 participants, 12,593 (20.1%) were identified as having metabolic syndrome, and we recorded 1,840 (2.9%) THRs and 1,111 (1.8%) TKRs during a mean follow-up time of 15.4 years. Cox regression analyses did not show any association between full metabolic syndrome and THR or TKR, except in persons <50 years with metabolic syndrome who had a decreased risk of THR (hazard ratio [HR] 0.58, 95% CI 0.40–0.83). However, when including only participants whose exposure status did not change during follow-up, this protective association was no longer significant. Increased waist circumference was associated with increased risk of TKR in participants <50 years (HR 1.62, 95% CI 1.10–2.39) and 50–69.9 years (HR 1.43, 95% CI 1.14–1.80). Hypertension significantly increased the risk of TKR in participants <50 years (HR 1.38, 95% CI 1.05–1.81), and this risk was greater for men. Conclusion: This study found an increased risk of TKR in men <50 years with hypertension and persons <70 years with increased waist circumference. Apart from this, neither metabolic syndrome nor its components were associated with increased risk of THR or TKR due to primary osteoarthritis

Metabolic syndrome as a risk factor for total hip or knee replacement due to primary osteoarthritis: A prospective cohort study (the HUNT study and the Norwegian arthroplasty register)

Objective: Biochemical changes associated with obesity may accelerate osteoarthritis beyond the effect of mechanical factors. This study investigated whether metabolic syndrome and its components (visceral obesity, hypertension, dyslipidemia and insulin resistance) were risk factors for subsequent total hip replacement (THR) or total knee replacement (TKR) due to primary osteoarthritis. Design: In this prospective cohort study, data from the second survey of the Nord-Trøndelag Health Study 2 (HUNT2) were linked to the Norwegian Arthroplasty Register for identification of the outcome of THR or TKR. The analyses were stratified by age (<50, 50–69.9 and ≥70 years) and adjusted for gender, body mass index, smoking, physical activity and education. Results: Of the 62,661 participants, 12,593 (20.1%) were identified as having metabolic syndrome, and we recorded 1,840 (2.9%) THRs and 1,111 (1.8%) TKRs during a mean follow-up time of 15.4 years. Cox regression analyses did not show any association between full metabolic syndrome and THR or TKR, except in persons <50 years with metabolic syndrome who had a decreased risk of THR (hazard ratio [HR] 0.58, 95% CI 0.40–0.83). However, when including only participants whose exposure status did not change during follow-up, this protective association was no longer significant. Increased waist circumference was associated with increased risk of TKR in participants <50 years (HR 1.62, 95% CI 1.10–2.39) and 50–69.9 years (HR 1.43, 95% CI 1.14–1.80). Hypertension significantly increased the risk of TKR in participants <50 years (HR 1.38, 95% CI 1.05–1.81), and this risk was greater for men. Conclusion: This study found an increased risk of TKR in men <50 years with hypertension and persons <70 years with increased waist circumference. Apart from this, neither metabolic syndrome nor its components were associated with increased risk of THR or TKR due to primary osteoarthritis

Age of menarche is associated with knee joint replacement due to primary osteoarthritis (The HUNT Study and the Norwegian Arthroplasty Register)

Objective To investigate whether parity, age at menarche, menopausal status, age at menopause, use of oral contraceptives (OC) or use of hormone replacement therapy (HRT) were associated with total knee replacement (TKR) or total hip replacement (THR) due to primary osteoarthritis. Method In a prospective cohort study of 30,289 women from the second and third surveys of the Nord-Trøndelag Health Study, data were linked to the Norwegian Arthroplasty Register (NAR) in order to identify TKR or THR due to primary osteoarthritis. Cox proportional hazards models were used to estimate the hazard ratios (HRs). Results We observed 430 TKRs and 675 THRs during a mean follow-up time of 8.3 years. Increasing age at menarche was inversely associated with the risk of TKR (P-trend < 0.001). Past users and users of systemic HRT were at higher risk of TKR compared to never users (HR 1.42 (95% confidence interval (CI) 1.06–1.90) and HR 1.40 (95% CI 1.03–1.90), respectively). No association was found between parity, age at menarche, menopausal status, age at menopause, oral contraceptive use or HRT use and THR. Conclusion We found that increasing age at menarche reduced the risk of TKR. Past users and users of systemic HRT were at higher risk of TKR compared to never users. Parity did not increase the risk of THR or TKR

Incidence of total hip or knee replacement due to osteoarthritis in relation to thyroid function: a prospective cohort study (The Nord-Trøndelag Health Study)

Background To study whether thyroid function was associated with risk of hip or knee replacement due to primary osteoarthritis. Methods In a prospective cohort study, data from the second and third survey of the Nord-Trøndelag Health Study were linked to the Norwegian Arthroplasty Register in order to identify total hip or knee replacement as a result of primary osteoarthritis. Results Among 37 891 participants without previously known thyroid disease we recorded 978 total hip replacements (THRs) and 538 total knee replacements (TKRs) during a median follow-up time of 15.7 years. The analyses were adjusted for sex, age, BMI (body mass index), smoking, physical activity and diabetes. We did not find any association between TSH (thyroid stimulating hormone) and THR or TKR due to osteoarthritis. Neither were changes in TSH over time, or overt hypo- or hyperthyroidism, associated with incidence of THR or TKR. Conclusion No association was found between thyroid function and hip or knee joint replacement due to osteoarthritis