Similar Clinical Outcomes with Preoperative and Postoperative Start of Thromboprophylaxis in THA: A Register-based Study.

BACKGROUND: Elective THA is associated with a high risk of thromboembolic events. Although these events may be less common now than they were in the past, they can be serious, and most patients undergoing the procedure therefore still receive thromboprophylaxis. However, controversy remains regarding whether to begin thromboprophylaxis before THA or after to best balance the risks of clotting and bleeding. QUESTIONS/PURPOSES: We asked the following questions: (1) Is there a difference in bleeding events with pre- versus postoperative thromboprophylaxis? (2) Is there a difference in thromboembolic episodes after THA between the two regimens? (3) How do the two approaches of thromboprophylaxis influence mortality, readmissions, and other complications? METHODS: We used a population-based followup design with predefined data based on international health codification to assess clinical effects of LMWH prophylaxis initiated before or after THA. We took data limited to primary THAs done in Norway between January 1, 2008, and December 31, 2011, from the Norwegian Arthroplasty Register and the National Patient Register to have necessary data elements to complete the study. The two registers were merged after identifying patients with their 11-digit personal identification number (Social Security number). We obtained data regarding demographics, administrative and surgical details, and episode histories for prophylaxis-related events within 180 days of surgery. A total of 25,163 patients undergoing THA were included for analysis, and 9977(40%) versus 15,186 (60%) patients received pre- and postoperative LMWH, respectively. We performed statistical adjustment for differences in baseline characteristics using multivariate logistic regression. RESULTS: After adjustment for age, sex, operation time, year of surgery, and American Society of Anesthesiologists class, we could not show major differences in bleeding events; (odds ratio [OR], 1.04; 95% CI, 0.88-1.22; p = 0.660), thromboembolic episodes; (OR, 1.03; 95% CI, 0.84-1.27; p = 0.786), or other postoperative clinical complications; (OR, 0.86; 95% CI, 0.76-0.99; p = 0.034), with the two regimens. Six-month mortality was similar, (OR, 0.76; 95% CI, 0.56-1.05; p = 0.093), and the readmission rate was higher in the preoperative group; (OR, 0.92; 95% CI, 0.85-0.97; p = 0.016). CONCLUSIONS: The risk for postoperative complications seems to be comparable whether LMWH prophylaxis is initiated before or after THA. The postoperative approach reduces costs, decreases risks related to neuraxial anesthesia, and facilitates same-day admissions. Methods for individual risk assessment including laboratory tests would be feasible. LEVEL OF EVIDENCE: Level III, therapeutic study.

Sham surgery versus labral repair or biceps tenodesis for type II SLAP lesions of the shoulder: a three-armed randomised clinical trial.

BACKGROUND: Labral repair and biceps tenodesis are routine operations for superior labrum anterior posterior (SLAP) lesion of the shoulder, but evidence of their efficacy is lacking. We evaluated the effect of labral repair, biceps tenodesis and sham surgery on SLAP lesions. METHODS: A double-blind, sham-controlled trial was conducted with 118 surgical candidates (mean age 40 years), with patient history, clinical symptoms and MRI arthrography indicating an isolated type II SLAP lesion. Patients were randomly assigned to either labral repair (n=40), biceps tenodesis (n=39) or sham surgery (n=39) if arthroscopy revealed an isolated SLAP II lesion. Primary outcomes at 6 and 24 months were clinical Rowe score ranging from 0 to 100 (best possible) and Western Ontario Shoulder Instability Index (WOSI) ranging from 0 (best possible) to 2100. Secondary outcomes were Oxford Instability Shoulder Score, change in main symptoms, EuroQol (EQ-5D and EQ-VAS), patient satisfaction and complications. RESULTS: There were no significant between-group differences at any follow-up in any outcome. Between-group differences in Rowe scores at 2 years were: biceps tenodesis versus labral repair: 1.0 (95% CI -5.4 to 7.4), p=0.76; biceps tenodesis versus sham surgery: 1.6 (95% CI -5.0 to 8.1), p=0.64; and labral repair versus sham surgery: 0.6 (95% CI -5.9 to 7.0), p=0.86. Similar results-no differences between groups-were found for WOSI scores. Postoperative stiffness occurred in five patients after labral repair and in four patients after tenodesis. CONCLUSION: Neither labral repair nor biceps tenodesis had any significant clinical benefit over sham surgery for patients with SLAP II lesions in the population studied. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT00586742.

Total Hip Arthroplasty With a Fully Hydroxyapatite-Coated Stem: A Cohort Study During 23-28 Years.

BACKGROUND: Long-term results of a hydroxyapatite (HA)-coated stem are sparse. We have followed a cohort of patients operated with a grit-blasted titanium stem designed for press-fit insertion and entirely plasma-sprayed with HA up to 28 years. METHODS: In the years 1988-1993, we performed 323 primary total hip arthroplasties in 276 patients (189 women). Their mean age was 48 (15-79) years. During the following years, 83 patients with 88 hips have died, and 18 patients did not attend the follow-up examination, but had no major symptoms according to telephone interviews and control examination. Thus, 212 patients (255 hips) were followed up for more than 20 years. RESULTS: Three patients were revised because of late periprosthetic infection, 1 because of a fall with periprosthetic fracture, and 2 stems were revised due to mechanical failure. Osteolysis was significantly associated with wear, and wear was significantly associated with the size of the femoral head. We found a small amount of proximal bone loss and a low incidence of distal hypertrophy of the bone. The bone changes confirmed a well-fixed femoral component in asymptomatic patients. CONCLUSION: Our findings indicate an essentially physiological weight distribution from the stem to the femoral bone with no significant thigh pain. The changes in the bone confirmed that the femoral component was well-fixed, and we conclude that a fully HA-coated titanium stem designed for press-fit insertion lasts for 23-28 years.

Femoral revision surgery using a fully hydroxyapatite-coated stem: a cohort study of twenty two to twenty seven years.

PURPOSE: Femoral component revision with either cemented or proximally coated stems has been disappointing, but revision with extensively coated stems has been promising. Our purpose was to evaluate the long-term outcome using an extensively hydroxyapatite (HA)-coated stem in femoral revisions surgery. METHODS: During 1988-1993 we performed 66 femoral revisions in 65 patients (49 women), mean age 58 (range, 28-86) years. We used a grit-blasted straight stem made of TiAl6V4 designed for press-fit insertion (Landos Corail; Landanger, Chaumont, France). In 48 hips we used primary stems of size 10 in two cases, size 11 in two, size 12 in seven, size 13 in four, size 14 in 12, size 15 in eight, size 16 in 12 and size 18 in one. In 18 cases, we used revision stems of size 12 in four cases, size 14 in seven, size 16 in five and size 18 in two. RESULTS: During follow-up, 21 patients have died. One patient had a traumatic fracture around the stem after six years, and another patient with osteoporosis developed fatigue fracture of the femoral bone after 22 years. In one patient the cup loosened after 23 years. The cup was revised, but deep infection occurred, and the patient underwent a two-stage revision of both components. Then, 12 of the revised stems were followed for more than ten years and 24 for more than 20 years. During this time only one stem was revised due to mechanical failure. This patient had a femoral defect classified to Type IV, and a proximal fracture occurred when the prosthesis was inserted. The fracture was stabilised by wires, but primary stability of the stem could not be obtained. At control examinations no patients suffered from significant thigh pain, and we noticed a low degree of proximal bone loss and a low incidence of distal bone hypertrophy. CONCLUSIONS: Our study suggests that a fully HA-coated stem in femoral revision surgery can provide reliable results for up to 27 years. The bone changes confirmed a well-fixed femoral component with a rather physiological transfer of stress from proximal to distal regions with no significant thigh pain.

Long-term results of a modified Spitzy shelf operation for residual hip dysplasia and subluxation. A fifty year follow-up study of fifty six children and young adults.

PURPOSE: The purposes of this study were to establish long-term outcome of the Spitzy shelf-operation and evaluate whether the procedure would delay osteoarthritis. METHODS: During 1954-1976, 56 patients (70 hips) underwent Spitzy shelf operation at a mean age of 11.9 years (5 to 22). Indications included residual hip dysplasia or subluxation with Centre-Edge angle < 20°. We used survival analysis with conversion to total hip replacements as end-point. For patients without total hip replacement, information was provided from case records and radiographs. Avascular necrosis was assessed in pre-Spitzy radiographs, when available. Kaplan-Meier product-limit method was used to estimate survival function of the Spitzy shelf operation. Survival was assessed by Cox regression. Univariable Cox regression was performed separately for each variable. Potential predictors (p-value < 0.10) were entered into a multivariable regression model; p-value < 0.05 was considered significant. RESULTS: Mean survival of the shelf procedure was 39.9 years (21 to 53). Survival fell from 83 % 30 years post-operatively, to 22 % at 50 years. Fifty-three hips (76 %) had undergone total hip replacement at mean age of 49.4 years (33 to 64). Seventeen hips had not received total hip replacement, mean survival 47.9 years (39 to 53). CONCLUSION: The study showed that Spitzy shelf-operation had satisfactory long-term outcome with hip-survival in almost 90 % at patient age 40 years. The results indicate that Spitzy shelf-operation postpone total hip replacement. We consider Spitzy shelf-operation a good alternative in patients above 8 years. In younger children the procedure is not recommended due to increased frequency of graft resorption.

Treatment outcome of chronic low back pain and radiographic lumbar disc degeneration are associated with inflammatory and matrix degrading gene variants: a prospective genetic association study.

BACKGROUND: Inflammatory and matrix degrading gene variants have been reported to be associated with disc degeneration. Some of these variants also modulate peripheral pain. This study examines the association of these genetic variants with radiographic lumbar disc degeneration and changes in pain and disability at long-term after surgical and cognitive behavioural management. METHODS: 93 unrelated patients with chronic low back pain (CLBP) for duration of >1 year and lumbar disc degeneration were treated with lumbar fusion or cognitive intervention and exercises. Standardised questionnaires included the Oswestry Disability Index (ODI) and Visual Analog Score (VAS) for CLBP, were filled in by patients both at baseline and at 9 years follow-up. Degenerative changes at baseline Magnetic Resonance Imaging and Computed Tomography scans, were graded as moderate and severe (N=79). Yield and quality of blood and saliva DNA was assessed by nano drop spectrophotometry. Eight SNPs in 5 inflammatory and matrix degrading genes were successfully genotyped. Single marker and haplotype association with severity of degeneration, number of discs involved, changes in ODI and VAS CLBP, was done using Haploview, linear regression and R-package Haplostats. RESULTS: Association analysis of individual SNPs revealed association of IL18RAP polymorphism rs1420100 with severe degeneration (p = 0.05) and more than one degenerated disc (p = 0.02). From the same gene two SNPs, rs917997 and rs1420106, were found to be in strong linkage disequilibrium (LD) and were associated with post treatment improvement in disability (p = 0.02). Haplotype association analysis of 5 SNPs spanning across IL18RAP, IL18R1 and IL1A genes revealed significant associations with improvement in disability (p=0.02) and reduction in pain (p=0.04). An association was found between MMP3 polymorphism rs72520913 and improvement in pain (p = 0.03) and with severe degeneration (p = 0.006). CONCLUSIONS: The findings of the current study suggest a role of variation at inflammatory and matrix degrading genes with severity of lumbar disc degeneration, pain and disability.

Perioperative mortality in hip fracture patients treated with cemented and uncemented hemiprosthesis: a register study of 11,210 patients.

PURPOSE: Adverse events associated with the use of bone cement for fixation of prostheses is a known complication. Due to inconclusive results in studies of hip fracture patients treated with cemented and uncemented hemiprostheses, this study was initiated. METHODS: Our study is based on data reported to the Norwegian Hip Fracture Register on 11,210 cervical hip fractures treated with hemiprostheses (8,674 cemented and 2,536 uncemented). RESULTS: Significantly increased mortality within the first day of surgery was found in the cemented group (relative risk 2.9, 95 % confidence interval 1.6-5.1, p=0.001). The finding was robust giving the same results after adjusting for independent risk factors such as age, sex, cognitive impairment and comorbidity [American Society of Anesthesiologists (ASA) score]. For the first post-operative day the number needed to harm was 116 (one death for every 116 cemented prosthesis). However, in the most comorbid group (ASA worse than 3), the number needed to harm was only 33. CONCLUSIONS: We found increased mortality for the cemented hemiprosthesis the first post-operative day compared to uncemented procedures. This increased risk is closely related to patient comorbidity estimated by the patient's ASA score.

Blood loss in cemented THA is not reduced with postoperative versus preoperative start of thromboprophylaxis.

BACKGROUND: Thrombin formation commences perioperatively in orthopaedic surgery and therefore some surgeons prefer preoperative initiation of pharmacologic thromboprophylaxis. However, because of the potential for increased surgical bleeding, the postoperative initiation of thromboprophylaxis has been advocated to reduce blood loss, need for transfusion, and bleeding complications. Trials on timing of thromboprophylaxis have been designed primarily to detect thrombotic events, and it has been difficult to interpret the magnitude of blood loss and bleeding events owing to lack of information for bleeding volume and underpowered bleeding end points. QUESTIONS/PURPOSES: We therefore asked whether there are differences in blood loss, transfusion requirements, and other postoperative clinical complications with preoperative versus postoperative start of thromboprophylaxis with dalteparin. METHODS: In a double-blind, randomized controlled trial, 80 patients undergoing primary cemented THA were allocated to dalteparin injections starting 12 hours before or 6 hours after surgery. Blood loss was measured by weighing sponges and drapes, volume in suction drains during surgery, and wound drains until removal 24 hours postoperatively. Hemoglobin and hematocrit were recorded at predefined times during and after surgery. RESULTS: We found no differences in blood loss (1081 mL ± 424 mL versus 1023 mL ± 238 mL), bleeding-related events (10% versus 17%), or number of patients who had transfusions (12 versus five) with preoperative and postoperative thromboprophylaxis, respectively. Other complications were few in both groups. CONCLUSIONS: Our data suggest blood loss is similar with preoperative and postoperative initiation of dalteparin thromboprophylaxis, but indicate a trend toward fewer transfusion requirements which might favor postoperative start of thromboprophylaxis.

Genetic contribution of catechol-O-methyltransferase variants in treatment outcome of low back pain: a prospective genetic association study.

BACKGROUND: Treatment outcome of low back pain (LBP) is associated with inter-individual variations in pain relief and functional disability. Genetic variants of catechol-O-methyltransferase (COMT) gene have previously been shown to be associated with pain sensitivity and pain medication. This study examines the association between COMT polymorphisms and 7-11 year change in Oswestry Disability Index (ODI) and Visual Analog Score (VAS) for LBP as clinical outcome variables in patients treated with surgical instrumented lumbar fusion or cognitive intervention and exercise. METHODS: 93 unrelated patients with chronic LBP for duration of >1 year and lumbar disc degeneration (LDD) were treated with lumbar fusion (N = 60) or cognitive therapy and exercises (N = 33). Standardised questionnaires assessing the ODI, VAS LBP, psychological factors and use of analgesics, were answered by patients both at baseline and at 7-11 years follow-up. Four SNPs in the COMT gene were successfully genotyped. Single marker as well as haplotype association with change in ODI and VAS LBP, were analyzed using Haploview, linear regression and R-package Haplostats. P-values were not formally corrected for multiple testing as this was an explorative study. RESULTS: Association analysis of individual SNPs adjusted for covariates revealed association of rs4633 and rs4680 with post treatment improvement in VAS LBP (p = 0.02, mean difference (ß) = 13.5 and p = 0.02, ß = 14.2 respectively). SNPs, rs4633 and rs4680 were found to be genotypically similar and in strong linkage disequilibrium (LD). A significant association was found with covariates, analgesics (p = 0.001, ß = 18.6); anxiety and depression (p = 0.008, ß = 15.4) and age (p = 0.03, mean difference per year (ß) = 0.7) at follow-up. There was a tendency for better improvement among heterozygous patients compared to the homozygous. No association was observed for the analysis of the common haplotypes, these SNPs were situated on. CONCLUSIONS: Results suggest an influence of genetic variants of COMT gene in describing the variation in pain after treatment for low back pain. Replication in large samples with testing for other pain related genes is warranted.

Long-term results after SLAP repair: a 5-year follow-up study of 107 patients with comparison of patients aged over and under 40 years.

PURPOSE: The aims of this prospective cohort study were to assess the long-term results after isolated superior labral repair and to determine whether the results were associated with age. METHODS: One hundred seven patients underwent repair of isolated SLAP tears. There were 36 women and 71 men with a mean age of 43.8 years (range, 20 to 68 years). Mean follow-up was 5.3 years (range, 4 to 8 years). Of the patients, 62 (57.9%) were aged 40 years or older. Follow-up examinations were performed by an independent examiner; 102 patients (95.3%) had a 5-year follow-up. RESULTS: The Rowe score improved from 62.8 (SD, 11.4) preoperatively to 92.1 (SD, 13.5) at follow-up (P < .001). Satisfaction was rated excellent/good for 90 patients (88%) at 5 years. There was no significant difference in the results for patients aged 40 years or older and those aged under 40 years. Difficulty with postoperative stiffness and pain was reported by 14 patients (13.1%). CONCLUSIONS: Our results suggest that long-term outcomes after isolated labral repair for SLAP lesions are good and independent of age. Postoperative stiffness was registered in 13.1% of the patients. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Biochemical lung, liver and kidney markers and early death among elderly following hip fracture.

INTRODUCTION: In the elderly, hip fracture is a common injury associated with high early mortality dominated by cardiorespiratory and thromboembolic events. Identification of risk factors that can be modified by treatment has caught attention over the last years. This study was conducted to assess biological markers on perioperative organ dysfunction and its association with early mortality within 3 months after surgery. METHOD: Blood samples were collected before, during and until 4 days after surgery. Analyses on PaO(2), alanine aminotransaminase (ALAT), gamma-glutamyl transpeptidase (g-GT) and creatinine were performed and used as markers on lung, liver and kidney functions. PATIENTS: Three hundred and two patients over 75 years of age with acute dislocated hip fracture were consecutively enrolled from two hospitals in Norway. RESULTS: We found a positive correlation between the plasma levels of ALAT, creatinine and death, and an inverse relationship between PaO(2) and death. After controlling for confounding factors such as sex, age and comorbidity, ALAT and creatinine levels were shown to be significantly and independently related to risk for fatal outcome. CONCLUSION: Our results provide data on clinically important biomarkers in patients undergoing hip fracture surgery. We suggest a stronger emphasis on monitoring and correcting these biomarkers when possible.

LBP and sCD14 patterns in total hip replacement surgery performed during combined spinal/epidural anaesthesia.

BACKGROUND: Danger patterns and pattern recognition receptors have been targets in the investigation and treatment of systemic inflammatory response syndrome and sepsis. Lipopolysaccharide (LPS)-binding protein (LBP) presents LPS and gram-positive bacterial cell wall products to the receptors TLR4/MD-2 and TLR2, respectively. Low concentrations of LBP stimulate responses to LPS and peptidoglycan, whereas higher concentrations inhibit these responses. Soluble CD14 (sCD14) presents the LBP-LPS complex to CD14-negative cells, and it modulates the biological activity of circulating LPS. In this study, we aimed to elucidate the physiological reactions to LBP and sCD14 after total hip replacement surgery during spinal/epidural anaesthesia. METHODS: Seven patients with coxarthrosis were operated upon with a total hip replacement, which is a defined trauma to bone and muscles in conjunction with a certain amount of blood loss. Venous blood samples were taken before the operation and at 1 h, 3 days and 6 days after surgery. LBP and sCD14 were measured by conventional ELISA. To correct for hemodilution, each parameter was adjusted for hematocrit. A panel of cytokines was measured using Luminex technology to evaluate the trauma reaction. RESULTS: IL-6 levels peaked 24 h after the operation, whereas IL-1ß and IL-10 levels remained unchanged. Systemic levels of LBP were increased 24 h after surgery, whereas sCD14 remained steady. However, the dilution-corrected sCD14 values increased significantly, and the levels of both LBP and sCD14 peaked at day 3 after surgery. CONCLUSION: Aseptic trauma primes the innate immune system for the posttraumatic release of LBP and sCD14.

Healing of long-term frozen orthotopic bone allografts is not affected by MHC differences between donor and recipient.

BACKGROUND: The use of bone grafting in orthopaedic surgery has increased dramatically in recent years. However, the degree to which immune responses are important for the survival of the allograft is not fully understood. In particular it remains unclear whether differences in the major histocompatibility complex (MHC) influence incorporation of bone allografts and their subsequent biologic performance. QUESTIONS/PURPOSES: Therefore, we asked whether isolated mismatch for MHC antigens of deep frozen bone allografts in the long-term causes (1) immune reactions, and whether these reactions have any effect on (2) morphologic features of the graft, (3) radiographic graft healing, and (4) graft strength. METHODS: We used an established orthotopic tibial segment transplantation technique that allows determination of mechanical strength, histologic evaluation, and immune responses. Tibial segments that had been deep-frozen at -80°C for 1 year were transplanted into 24 PVG (RT1 (c)) rats from either 12 syngeneic donors or 12 MHC congenic donors PVG.1U (RT1 (u)). We determined immune responses using an indirect Coombs reaction and determined graft healing radiographically and mechanically after 6 months. RESULTS: We detected no alloantibody production to graft MHC-I antigens, and found no differences between syngeneic and MHC mismatched grafts in terms of remodeling with host bone, graft healing, and mechanical strength. CONCLUSIONS: Mismatches for MHC antigens do not seem to play a decisive role in healing of long-term, deep-frozen bone allografts.

Reliability, agreement and validity of the 1988 version of the Rowe Score.

BACKGROUND: The aim of this study was to evaluate reliability, agreement, and validity of the 1988 version of the Rowe score in patients with superior glenoid labrum lesions (SLAP) or recurrent anterior dislocations. METHODS: Thirty-eight patients with SLAP lesions and 33 with anterior recurrent dislocations were independently tested twice by 2 experienced clinicians with the 1988 version of the Rowe score. In addition, the patients completed disease specific and generic questionnaires--the Western Ontario Shoulders Instability Index (WOSI), Oxford Instability Shoulder Score (OISS), and EuroQol (EQ-5D and EQ-VAS)--at both test days. RESULTS: No significant differences between clinicians and test days were detected for the Rowe score. Limits of agreement of the total score varied from -17.9 to 20.5. For the categorical score (total units), there were significant differences between the 2 examiners (P < .001). The ICC 2.1 was acceptable (>.70) for the total score. No floor or ceiling effects were observed for the total score, but considerable floor and/or ceiling effects were detected for some of the domains. Discriminant validity was acceptable, but content, construct, or convergent validity was not acceptable. CONCLUSION: Results using the 1988 version of the Rowe score should be critically interpreted.

Clinical and biochemical prediction of early fatal outcome following hip fracture in the elderly.

Hip fracture, a moderate musculoskeletal trauma, is associated with a high postoperative mortality. Most patients are elderly, with comorbid conditions and often with heart disease. The objective of this study was to find out if clinical parameters and analyses of specific muscle enzymes could predict three month postoperative mortality. A total of 302 patients above 75 years of age with hip fracture were consecutively enrolled. Baseline information on age, sex and comorbidity assessed with the American Society of Anesthesiologists (ASA) score was obtained before surgery. Creatine kinase (CK), myocardium-specific creatine kinase (CK-MB) and troponin T (TnT) were analysed from venous blood, collected the day before surgery (-1) and postoperatively, within 24 hours (0) and on days one (+1) and four (+4). The overall three month mortality was 19.5%. Multivariate analyses showed that age, male sex and comorbidity (ASA) correlated with mortality (p = 0.027, p = 0.002, p < 0.001, respectively). Surgery induced a two- to threefold increase of CK and CK-MB but without any correlation with mortality. However, high TnT levels >0.04 µg/l correlated significantly with death (days -1, +1 and +4, p = 0.003, p = 0.005 and p = 0.003, respectively). Multivariate analyses, adjusted for age, sex and ASA category, confirmed this correlation (day +4, p = 0.008). Thus, in elderly patients with comorbidities undergoing hip fracture surgery information on sex, age, ASA category and postoperative laboratory analyses on TnT provide the clinicians with useful information on patients at risk of fatal outcome.

Calcium phosphate bone cement: a possible alternative to autologous bone graft. A radiological and biomechanical comparison in rat tibial bone.

BACKGROUND: Donor site morbidity is a problem after autologous bone transplantation. An injectable CaP bone cement indicates properties similar to bone. MATERIALS AND METHODS: Double osteotomies on rat tibias were performed. The intercalated segments were avascular (10), vascular (10), or avascular with Norian SRS(®) CaP bone cement replacing cancellous bone (10). Controls were non-operated contralateral tibias (15). All osteotomies were stabilised with an intra-medullary nail. After 8 weeks, all rats were killed. The harvested tibias were compared using X-ray, DEXA scanning, microCT scans and a biomechanical torsional test. RESULTS: No difference in healing processes or biomechanical results has been found between the avascular bone graft, vascular bone graft and CaP bone cement groups. CONCLUSION: The injectable CaP bone cement confirms its similarities to bone, implying that it can be used as an adjunct to secure bone fragments and as a possible alternative to autologous bone transplantation in clinical practice.

Four-year follow-up of surgical versus non-surgical therapy for chronic low back pain.

OBJECTIVES: To compare the long-term effectiveness of surgical and non-surgical treatment in patients with chronic low back pain. METHODS: Two merged randomised clinical trials compared instrumented transpedicular fusion with cognitive intervention and exercises in 124 patients with disc degeneration and at least 1 year of symptoms after or without previous surgery for disc herniation. The main outcome measure was the Oswestry disability index. RESULTS: At 4 years 14 (24%) patients randomly assigned to cognitive intervention and exercises had also undergone surgery. 15 (23%) patients assigned fusion had undergone re-surgery. The mean treatment effect for the primary outcome was 1.1; 95% CI -5.9 to 8.2, according to the intention-to-treat analysis and -1.6; 95% CI -8.9 to 5.6 in the as-treated analysis. There was no difference in return to work. CONCLUSIONS: Long-term improvement was not better after instrumented transpedicular fusion compared with cognitive intervention and exercises.