Prognostic occupational factors for persistent low back pain in primary care.

PURPOSE: To reduce the socio-economic burden of persistent low back pain (LBP), factors influencing the progression of acute/subacute LBP to the persistent state must be identified at an early stage. METHODS: Prospective inception cohort study of patients attending a health practitioner for their first episode of acute/subacute or recurrent LBP. Patients were assessed at baseline addressing occupational, psychological, biomedical and demographic/lifestyle factors and followed up over 6 months. Multivariate logistic regression analysis was performed separately for the variables groups of the four different domains, controlling for age, gender and body mass index. The overall predictive value was calculated for the full regression models of the different domains. Finally, all significant variables from the different domains were combined into a final predictor model. RESULTS: The final four-predictor model predicted 51 % of variance of persistent LBP and included 'resigned attitude towards the job' (OR 1.73; 95 % CI 1.16-2.59), 'social support at work' (OR 0.54; 95 % CI 0.32-0.90), 'functional limitation' (OR 1.05; 95 % CI 1.01-1.10) and 'duration of LBP' (OR 1.04; 95 % CI 1.02-1.06). The accuracy of the model was 83 %, with 92 % of non-persistent and 67 % of persistent LBP patients correctly identified. CONCLUSIONS: In this study of patients with acute/subacute LBP, 'resigned attitude towards the job' increased the likelihood of persistent LBP at 6 month. Addressing this factor with workplace interventions has the potential to modify the outcome. In patients experiencing 'social support at work', the development of persistent LBP was less likely and might therefore be considered as potential resource for prevention of persistent LBP.

Depression impacts the course of recovery in patients with acute low-back pain.

Little is known about the course of recovery of acute low back pain (LBP) patients as a function of depression. In a prospective study, 286 acute LBP patients were assessed at baseline and followed up over 6 months. Recovery was defined as improvement in the Oswestry Disability Index (ODI). Repeated-measures analysis of covariance was employed with ODI as repeated factor, age, sex, and body mass index as covariates, depression and all other potential prognostic factors as between-subject factors. Of study participants, 18% were classified as depressive (>33 points on the Zung Self-Rating Depression Scale). Of 286 participants, 135 were lost to follow-up. In the longitudinal sample of 151 patients the course of recovery was slower in depressive patients. Depression was associated with LBP especially after 6 weeks and should therefore be included in screening instruments for acute LBP patients to identify those at risk of delayed recovery at an early stage.

Occupational, personal and psychosocial resources for preventing persistent low back pain.

The aim of this prospective cohort study was to identify modifiable protective factors of the progression of acute/subacute low back pain (LBP) to the persistent state at an early stage to reduce the socioeconomic burden of persistent LBP. Patients attending a health practitioner for acute/subacute LBP were assessed at baseline addressing occupational, personal and psychosocial factors, and followed up over 12 weeks. Pearson correlations were calculated between these baseline factors and the presence of nonpersistent LBP at 12-week follow-up. For those factors found to be significant, multivariate logistic regression analyses were performed. The final 3-predictor model included job satisfaction, mental health and social support. The accuracy of the model was 72%, with 81% of nonpersistent and 60% of persistent LBP patients correctly identified. Further research is necessary to confirm the role of different types of social support regarding their prognostic influence on the development of persistent LBP.

Interventions for treating acute elbow dislocations in adults.

BACKGROUND: Dislocation of the elbow joint is a relatively uncommon injury. OBJECTIVES: To assess the effects of various forms of treatment for acute simple elbow dislocations in adults. SEARCH METHODS: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (April 2011), the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2011 Issue 1), MEDLINE (1948 to March Week 5 2011), EMBASE (1980 to 2011 Week 14), PEDro (April 2011), CINAHL (April 2011), various trial registers, various conference proceedings and bibliographies of relevant articles. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials of conservative and surgical treatment of dislocations of the elbow in adults. Excluded were trials involving dislocations with associated fractures, except for avulsion fractures. DATA COLLECTION AND ANALYSIS: Data extraction and assessment of risk of bias were independently performed by two review authors. There was no pooling of data. MAIN RESULTS: Two small randomised controlled trials, involving a total of 80 participants with simple elbow dislocations, were included. Both trials were methodologically flawed and potentially biased.One trial, involving 50 participants, compared early mobilisation at three days post reduction versus cast immobilisation. At one year follow-up, the recovery of range of motion appeared better in the early mobilisation group (e.g. participants with incomplete recovery of extension: 1/24 versus 5/26; risk ratio 0.22, 95% confidence interval 0.03 to 1.72). However, the results were not statistically significant. There were no reports of instability or recurrence. One person in each group had residual pain at one year.The other trial, involving 30 participants, compared surgical repair of the torn ligaments versus conservative treatment (cast immobilisation for two weeks). At final follow-up (mean 27.5 months), there were no statistically significant differences between the two groups in the numbers of patients who considered their injured elbow to be inferior to their non-injured elbow (10/14 versus 7/14; RR 1.43, 95% CI 0.77 to 2.66) or in other patient complaints about their elbow such as weakness, pain or weather-related discomfort. There were no reports of instability or recurrence. There were no statistically significant differences between the two groups in range of motion of the elbow (extension, flexion, pronation, and supination) or grip strength at follow-up. No participants had neurological disturbances of the hand but two surgical group participants had recurrent dislocation of the ulnar nerve (no other details provided). One person in each group had radiologically detected myositis ossificans (bone formation within muscles following injury). AUTHORS' CONCLUSIONS: There is insufficient evidence from randomised controlled trials to determine which method of treatment is the most appropriate for simple dislocations of the elbow in adults. Although weak and inconclusive, the available evidence from a trial comparing surgery versus conservative treatment does not suggest that the surgical repair of elbow ligaments for simple elbow dislocation improves long-term function. Future research should focus on questions relating to non-surgical treatment, such as the duration of immobilisation.

WITHDRAWN: Rehabilitation after surgery for flexor tendon injuries in the hand.

BACKGROUND: Postoperative rehabilitation of the flexor tendons in the hand consists of a short period of immobilisation while pain and swelling diminish, followed by progressive mobilisation to maximize the range of motion of the affected fingers. By altering the time of immobilisation and the manner of subsequent mobilisation different rehabilitation regimes are created. OBJECTIVES: To determine, with evidence from randomised controlled trials, the optimal rehabilitation strategy after surgery for flexor tendon injuries in the hand. SEARCH STRATEGY: We searched the Cochrane Bone, Joint and Muscle Trauma Group specialised register (November 2002), the Cochrane Central Register of Controlled Trials (The Cochrane Library, issue 4, 2002), MEDLINE (1966 to November 2002), EMBASE (1988 to November 2002), CINAHL (1982 to October 2002), CURRENT CONTENTS (1993 to October 2002), PEDro - The Physiotherapy Evidence Database (http://ptwww.cchs.usyd.edu.au/pedro/ accessed 30/10/2002) and reference lists of articles. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials of interventions for rehabilitation after surgery of flexor tendon injuries in the hand after surgery. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality, using a 10 item scale, and extracted data where possible. Additional information was sought from trialists when required. Due to the lack of extractable data and the variety of interventions used, pooling was not attempted. Where possible relative risks and 95 per cent confidence intervals were calculated for dichotomous outcomes, and mean differences and 95 per cent confidence intervals calculated for continuous outcomes. MAIN RESULTS: Six trials, including three reported only in abstracts, with a total of 464 participants were included. Data were not pooled. One trial compared continuous passive motion (CPM) with controlled intermittent passive motion (CIPM) and found a significant difference in mean active motion favouring CPM (WMD 19.00 degrees, 95% CI 15.11 to 22.89). One trial compared a shortened passive flexion/active extension programme with a normal passive flexion/active extension mobilisation programme, and reported (without data) a significant reduction in absence from work of 2.1 weeks in favour of the shortened programme. Other trials compared active flexion with rubber band traction, early controlled active mobilisation with early controlled passive mobilisation and dynamic splintage versus static splintage. No trials found significant differences in overall functioning or complication rate. AUTHORS' CONCLUSIONS: Controlled mobilisation regimens are widely employed in rehabilitation after flexor tendon repair in the hand. This review found insufficient evidence from randomised controlled trials to define the best mobilisation strategy.

Results of porous-coated anatomic and duracon total knee arthroplasty.

The Duracon total knee replacement and its forerunner the Porous-Coated Anatomic (PCA) knee system have been associated with good results. This study reviews a series of 181 knee replacements performed with these systems by seven general orthopedic surgeons with follow-up to a mean of 6.7 years. The mean Knee Society knee and function scores were 72 and 68. The mean Western Ontario and MacMaster Universities Osteoarthritis Index score was 76, and the mean 12-Item Short-Form Health Survey result was 55. A mean flexion of 104 degrees was recorded, and 93.8% of patients rated their satisfaction as good to excellent. Fifty-five percent of patients had minor radiographic lucencies-these were of questionable clinical significance. Seven patients required revision. These knee systems used in a relatively low-volume general unit provide consistent results comparable with those from larger arthroplasty units.

Total posterior condylar separation in a juvenile knee: open fixation through a posterior arthrotomy.

The authors report a case of separation involving the posterior aspect of the lateral femoral condyle in a 13-year-old boy. The patient presented with a 2-year history of vague knee discomfort and recurrent knee effusions in the absence of a single acute traumatic event. A large mobile osteochondral fragment involving most of the posterior aspect of the lateral condyle was refixed surgically with two screws via a posterolateral arthrotomy. The knee has recovered full function and the lesion is radiologically stable.

The diagnostic value of a treadmill test in predicting lumbar spinal stenosis.

Lumbar spinal stenosis is a frequent indication for spinal surgery. The predictive quality of treadmill testing and MRI for diagnostic verification is not yet clearly defined. Aim of the current study was to assess correlations between treadmill testing and MRI findings in the lumbar spine. Twenty-five patients with lumbar spinal stenosis were prospectively examined. Treadmill tests were performed and the area of the dural sac and neuroforamina was examined with MRI for the narrowest spinal segment. VAS and ODI were used for clinical assessment. The median age of the patients was 67 years. In the narrowest spinal segment the median area of the dural sac was 91 mm(2). The median ODI was 66 per cent. The median walking distance in the treadmill test was 70 m. The distance reached in the treadmill test correlated with the area of the dural sac (Spearman's rho = 0.53) and ODI (rho = -0.51), but not with the area of the neuroforamina and VAS. The distance reached in the treadmill test predicts the grade of stenosis in MRI but has a limited diagnostic importance for the level of clinical symptoms in lumbar spinal stenosis.

The international spine registry SPINE TANGO: status quo and first results.

With an official life time of over 5 years, Spine Tango can meanwhile be considered the first international spine registry. In this paper we present an overview of frequency statistics of Spine Tango for demonstrating the genesis of questionnaire development and the constantly increasing activity in the registry. Results from two exemplar studies serve for showing concepts of data analysis applied to a spine registry. Between 2002 and 2006, about 6,000 datasets were submitted by 25 centres. Descriptive analyses were performed for demographic, surgical and follow-up data of three generations of the Spine Tango surgery and follow-up forms. The two exemplar studies used multiple linear regression models to identify potential predictor variables for the occurrence of dura lesions in posterior spinal fusion, and to evaluate which covariates influenced the length of hospital stay. Over the study period there was a rise in median patient age from 52.3 to 58.6 years in the Spine Tango data pool and an increasing percentage of degenerative diseases as main pathology from 59.9 to 71.4%. Posterior decompression was the most frequent surgical measure. About one-third of all patients had documented follow-ups. The complication rate remained below 10%. The exemplar studies identified "centre of intervention" and "number of segments of fusion" as predictors of the occurrence of dura lesions in posterior spinal fusion surgery. Length of hospital stay among patients with posterior fusion was significantly influenced by "centre of intervention", "surgeon credentials", "number of segments of fusion", "age group" and "sex". Data analysis from Spine Tango is possible but complicated by the incompatibility of questionnaire generations 1 and 2 with the more recent generation 3. Although descriptive and also analytic studies at evidence level 2++ can be performed, findings cannot yet be generalised to any specific country or patient population. Current limitations of Spine Tango include the low number and short duration of follow-ups and the lack of sufficiently detailed patient data on subgroup levels. Although the number of participants is steadily growing, no country is yet represented with a sufficient number of hospitals. Nevertheless, the benefits of the project for the whole spine community become increasingly visible.

Differences across health care systems in outcome and cost-utility of surgical and conservative treatment of chronic low back pain: a study protocol.

BACKGROUND: There is little evidence on differences across health care systems in choice and outcome of the treatment of chronic low back pain (CLBP) with spinal surgery and conservative treatment as the main options. At least six randomised controlled trials comparing these two options have been performed; they show conflicting results without clear-cut evidence for superior effectiveness of any of the evaluated interventions and could not address whether treatment effect varied across patient subgroups. Cost-utility analyses display inconsistent results when comparing surgical and conservative treatment of CLBP. Due to its higher feasibility, we chose to conduct a prospective observational cohort study. METHODS: This study aims to examine if1. Differences across health care systems result in different treatment outcomes of surgical and conservative treatment of CLBP2. Patient characteristics (work-related, psychological factors, etc.) and co-interventions (physiotherapy, cognitive behavioural therapy, return-to-work programs, etc.) modify the outcome of treatment for CLBP3. Cost-utility in terms of quality-adjusted life years differs between surgical and conservative treatment of CLBP. This study will recruit 1000 patients from orthopaedic spine units, rehabilitation centres, and pain clinics in Switzerland and New Zealand. Effectiveness will be measured by the Oswestry Disability Index (ODI) at baseline and after six months. The change in ODI will be the primary endpoint of this study. Multiple linear regression models will be used, with the change in ODI from baseline to six months as the dependent variable and the type of health care system, type of treatment, patient characteristics, and co-interventions as independent variables. Interactions will be incorporated between type of treatment and different co-interventions and patient characteristics. Cost-utility will be measured with an index based on EQol-5D in combination with cost data. CONCLUSION: This study will provide evidence if differences across health care systems in the outcome of treatment of CLBP exist. It will classify patients with CLBP into different clinical subgroups and help to identify specific target groups who might benefit from specific surgical or conservative interventions. Furthermore, cost-utility differences will be identified for different groups of patients with CLBP. Main results of this study should be replicated in future studies on CLBP.

Development of a screening tool predicting the transition from acute to chronic low back pain for patients in a GP setting: protocol of a multinational prospective cohort study.

BACKGROUND: Low back pain (LBP) is by far the most prevalent and costly musculoskeletal problem in our society today. Following the recommendations of the Multinational Musculoskeletal Inception Cohort Study (MMICS) Statement, our study aims to define outcome assessment tools for patients with acute LBP and the time point at which chronic LBP becomes manifest and to identify patient characteristics which increase the risk of chronicity. METHODS: Patients with acute LBP will be recruited from clinics of general practitioners (GPs) in New Zealand (NZ) and Switzerland (CH). They will be assessed by postal survey at baseline and at 3, 6, 12 weeks and 6 months follow-up. Primary outcome will be disability as measured by the Oswestry Disability Index (ODI); key secondary endpoints will be general health as measured by the acute SF-12 and pain as measured on the Visual Analogue Scale (VAS). A subgroup analysis of different assessment instruments and baseline characteristics will be performed using multiple linear regression models. This study aims to examine: 1. Which biomedical, psychological, social, and occupational outcome assessment tools are identifiers for the transition from acute to chronic LBP and at which time point this transition becomes manifest. 2. Which psychosocial and occupational baseline characteristics like work status and period of work absenteeism influence the course from acute to chronic LBP. 3. Differences in outcome assessment tools and baseline characteristics of patients in NZ compared with CH. DISCUSSION: This study will develop a screening tool for patients with acute LBP to be used in GP clinics to access the risk of developing chronic LBP. In addition, biomedical, psychological, social, and occupational patient characteristics which influence the course from acute to chronic LBP will be identified. Furthermore, an appropriate time point for follow-ups will be given to detect this transition. The generalizability of our findings will be enhanced by the international perspective of this study. TRIAL REGISTRATION: [Clinical Trial Registration Number, ACTRN12608000520336].

Pelvic pseudotumor: an unusual presentation of an extra-articular granuloma in a well-fixed total hip arthroplasty.

A 76-year-old woman developed a pelvic mass and abdominal pain 12 years after cementless total hip arthroplasty. The mass was a cystic granuloma that communicated with the hip joint via a soft tissue herniation under the inguinal ligament. There was no acetabular lysis or defects. The shell and femoral component were well fixed, the polyethylene was worn, and a liner exchange was undertaken. The cyst was debrided, and follow-up computed tomography demonstrated resolution of the granuloma and no recurrence of the cyst. Removal of the source of the particle wear debris via liner exchange or revision surgery combined with cyst debridement via a single incision is recommended.

Comparison of infection rate using different methods of assessment for surveillance of total hip replacement surgical site infections.

BACKGROUND: The surveillance of surgical site infections (SSI) has been undertaken in many centres worldwide to ascertain the extent of the problem and where possible, to improve the incidence rates, thereby decreasing the undesirable outcomes. The study investigates the processes and outcomes of total hip replacement SSI surveillance carried out in Dunedin Public Hospital in 2004. METHODS: Two hundred and six patients were enlisted in the study and 189 primary replacements and 22 revision replacements were carried out. Four methods of diagnosis of SSI were applied: (i) clinician diagnosis; (ii) ASEPSIS score; (iii) presence of pus cells; and (iv) assessment by a clinical microbiologist. Infection rates were calculated according to the risk indexes. RESULTS: The incidence of infections varies considerably among these four methods. The infection rates for risk index 0 were 4.35% (method 1), 2.61% (method 2), 0.87% (methods 3 and 4); and for risk indexes 1 and 2 were 4.17% (method 1), 2.08% (method 2), 1.04% (methods 3 and 4). CONCLUSION: There is a need for accurate infection data so that the appropriate follow-up responses, including infection control measures for total hip replacement SSI can be carried out. The preponderance of elderly patients in the study who are frequently on 'polypharmacy' regimens adds pressure to the need to obtain true infection rates. This is because when antimicrobials are prescribed to them, drug interactions, adverse effects of the antimicrobials and the selective pressure of antimicrobials causing resistances may occur. More resources and a multidisciplinary approach are required for future studies of similar nature.

Factors affecting implant retention in infected joint replacements.

BACKGROUND: There is no standard treatment for infected joint replacements. The options available are varied, and treatment choices may pose problems in relation to both efficacy and cost-effectiveness. METHODS: A retrospective review of 73 patient records identified in our departmental audit database as infected joint replacements treated at Dunedin Hospital between 1990 and 2000 was carried out. The findings were analysed in terms of outcome of primary treatment, final outcome including prosthesis retention and bacteriology. RESULTS: Of the 73 patients (50 hips and 20 knees), the majority (69%) were managed by primary surgical debridement followed by intravenous antibiotics but about one-third (34%) lost their implants because of infection. Retention of implants was higher in acute infections (85-100%) as opposed to late infections (20-50%). The microbiological analysis showed that Staphylococcus and Streptococcus caused the majority (76%) of infections. CONCLUSION: In our series, a patient with an infected joint replacement had an approximately similar 30% chance of retaining the original prosthesis, undergoing a successful revision and having no implants in situ at the end of treatment.

Outcome of acute hospital admission for non-specific low back pain: what is the role of MRI?

BACKGROUND: Low back pain is a common worldwide condition, affecting most people during their lifetime. Various imaging modalities are being used to assist clinicians in diagnosing and thus, aid in formulating a suitable management plan. Extensive research has been carried out in assessing this condition due to its high prevalence, with many guidelines published internationally. AIM: To determine whether MRI imaging influences the management of patients admitted with acute, non-specific low back pain between 1 January 2013 and 31 December 2015. METHOD: A total of 209 patients who met the inclusion criteria were included in the study. Suitable patients were initially identified from the ward admission book. Subsequently, relevant data regarding patient admission and management within the two-year period were obtained from the hospital patient management system, including radiology reports. RESULTS: Out of the 209 patients included in this study, 131 patients (63%) had an MRI as part of the diagnostic process. Most patients were managed non-operatively with only 41 (20%) out of the 209 patients having undergone acute surgery while an inpatient. In this subgroup, 38 had an MRI done prior to surgery. Among the 168 patients who were treated non-operatively, including epidural steroid injection, 13 patients (8%) had elective surgery within one year from their initial presentation. CONCLUSION: Use of MRI can aid in the early diagnosis and facilitate faster rehabilitation for patients. It can also potentially reduce patient stay in hospital and result in significant cost savings for the healthcare system. Imaging guidelines should be developed in the assessment of patients with low back pain in an acute hospital setting.

Late presenting dislocation of sonographically stable hips.

We report on seven developmental hip dislocations in five babies (age 6-22 months) in whom ultrasound had demonstrated reduced and stable hips. Four hips in three babies had been diagnosed as having clinical instability (Barlow positive) at birth, which had stabilized by the time of the scan (16-45 days). Femoral head coverage ranged from 36 to 56%. One hip had minimal sonographic laxity on stress examination. Hips that are reduced and stable sonographically at 2-6 weeks of age can subsequently dislocate. Any child with instability at birth should be reviewed with a pelvic radiograph at 4-6 months, even if an ultrasound scan appears to be normal.

Movement Patterns of the Knee During Gait Following ACL Reconstruction: A Systematic Review and Meta-Analysis.

BACKGROUND: Altered gait patterns follow ing anterior cruciate ligament reconstruction (ACLR) may be associated with long-term impairments and post-traumatic osteoarthritis. OBJECTIVE: This systematic review and meta-analysis compared lower limb kinematics and kinetics of the ACL reconstructed knee with (1) the contralateral limb and (2) healthy age-matched participants during walking, stair climbing, and running. The secondary aim was to describe the differences over time following ACLR for these biomechanical variables. METHOD: Database searches were conducted from inception to July 2014 and updated in August 2015 for studies exploring peak knee angles and moments following ACLR during walking, stair negotiation, and running. Risk of bias was assessed with a modified Downs and Black quality index for all included studies, and meta-analyses were performed. Forest plots were explored qualitatively for recovery of gait variables over time after surgery. RESULTS: A total of 40 studies were included in the review; 26 of these were rated as low risk and 14 as high risk of bias. The meta-analysis included 27 studies. Strong to moderate evidence indicated no significant difference in peak flexion angles between ACLR and control groups during walking and stair ascent. Strong evidence was found for lower peak flexion moments in participants with ACLR compared with control groups and contralateral limb during walking and stair activities. Strong to moderate evidence was found for lower peak adduction moment in ACLR participants for the injured compared with the contralateral limbs during walking and stair descent. The qualitative assessment for recovery over time indicated a pattern towards restoration of peak knee flexion angle with increasing time from post-surgery. Peak knee adduction moments were lower within the first year following surgery and higher than controls during later phases (5 years). CONCLUSION: Joint kinematics are restored, on average, 6 years following reconstruction, while knee external flexion moments remain lower than controls. Knee adduction moments are lower during early phases following reconstruction, but are higher than controls, on average, 5 years post-surgery. Findings indicate that knee function is not fully restored following reconstruction, and long-term maintenance programs may be needed.

Effects of bone morphogenetic protein-2 and hyaluronic acid on the osseointegration of hydroxyapatite-coated implants: an experimental study in sheep.

Research efforts aim at enhancing early osseointegration of cementless implants to improve early fixation and, thus, reduce the risk of loosening. The aim of the present study was to investigate whether bone morphogenetic protein (BMP) 2 had a positive effect on the osseointegration of hydroxyapatite-coated implants. Hydroxyapatite (HA) implants (perforated hollow cylinders and solid rods) were coated with BMP-2 and hyaluronic acid (HY) as the carrier or with HY alone. Uncoated HA implants served as controls. The osseointegration of the implants was evaluated either by light microscopy or by pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 24 sheep. The BMP-2 coating significantly increased bone growth into the implant perforations compared with HA-coated implants at 2 and 4 weeks. Bone-implant contact and interface shear strength of BMP-2 implants were lower than HA implants at 2 weeks. At 4 weeks, there was no significant difference in bone-implant contact and shear strength between BMP-2 and HA-coated implants. The BMP-2 coating enhanced gap healing but had no positive or even an inhibitory effect (at 2 weeks) on bone-implant contact and interface shear strength. In the clinical situation, a perfect press-fit implantation cannot be achieved, and BMP-2 may be beneficial for enhancing bone growth into gaps around cementless implants.

What is the best time point to identify patients at risk of developing persistent low back pain?

BACKGROUND: Early identification of patients at risk of developing persistent low back pain (LBP) is crucial. OBJECTIVE: Aim of this study was to identify in patients with a new episode of LBP the time point at which those at risk of developing persistent LBP can be best identified. METHODS: Prospective cohort study of 315 patients presenting to a health practitioner with a first episode of acute LBP. Primary outcome measure was functional limitation. Patients were assessed at baseline, three, six, twelve weeks and six months looking at factors of maladaptive cognition as potential predictors. Multivariate logistic regression analysis was performed for all time points. RESULTS: The best time point to predict the development of persistent LBP at six months was the twelve-week follow-up (sensitivity 78%; overall predictive value 90%). Cognitions assessed at first visit to a health practitioner were not predictive. CONCLUSIONS: Maladaptive cognitions at twelve weeks appear to be suitable predictors for a transition from acute to persistent LBP. Already three weeks after patients present to a health practitioner with acute LBP cognitions might influence the development of persistent LBP. Therefore, cognitive-behavioral interventions should be considered as early adjuvant LBP treatment in patients at risk of developing persistent LBP.

In vivo comparison of the osseointegration of vacuum plasma sprayed titanium- and hydroxyapatite-coated implants.

For the last 15 years, orthopedic implants have been coated with hydroxyapatite (HA) to improve implant fixation. The osteoconductive effect of HA coatings has been demonstrated in experimental and clinical studies. However, there are ongoing developments to improve the quality of HA coatings. The objective of this study was to investigate whether a rough and highly crystalline HA coating applied by vacuum plasma spraying (VPS) had a positive effect on the osseointegration of special, high-grade titanium (Ti) implants with the same surface roughness. Ti alloy implants were coated (VPS) with special, high-grade Ti or HA. The osseointegration of the implants was evaluated by either light microscopy or pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 18 sheep. The interface shear strength increased significantly over all time intervals. By 4 weeks, values had reached approximately 10N/mm(2). However, the difference between the coatings was not significant at any time interval. Direct bone-implant contact was significantly different between the coatings after 2 and 4 weeks, and reached 46% for Ti and 68% for HA implants by 4 weeks. This study indicates that the use of a rough and highly crystalline HA coating, applied by VPS, enhances early osseointegration. Accelerated establishment of secondary implant fixation decreases the risk of early loosening.