Development and validation of AI-based automatic measurement of coronal Cobb angles in degenerative scoliosis using sagittal lumbar MRI.

OBJECTIVES: Severity of degenerative scoliosis (DS) is assessed by measuring the Cobb angle on anteroposterior radiographs. However, MRI images are often available to study the degenerative spine. This retrospective study aims to develop and evaluate the reliability of a novel automatic method that measures coronal Cobb angles on lumbar MRI in DS patients. MATERIALS AND METHODS: Vertebrae and intervertebral discs were automatically segmented using a 3D AI algorithm, trained on 447 lumbar MRI series. The segmentations were used to calculate all possible angles between the vertebral endplates, with the largest being the Cobb angle. The results were validated with 50 high-resolution sagittal lumbar MRI scans of DS patients, in which three experienced readers measured the Cobb angle. Reliability was determined using the intraclass correlation coefficient (ICC). RESULTS: The ICCs between the readers ranged from 0.90 (95% CI 0.83-0.94) to 0.93 (95% CI 0.88-0.96). The ICC between the maximum angle found by the algorithm and the average manually measured Cobb angles was 0.83 (95% CI 0.71-0.90). In 9 out of the 50 cases (18%), all readers agreed on both vertebral levels for Cobb angle measurement. When using the algorithm to extract the angles at the vertebral levels chosen by the readers, the ICCs ranged from 0.92 (95% CI 0.87-0.96) to 0.97 (95% CI 0.94-0.98). CONCLUSION: The Cobb angle can be accurately measured on MRI using the newly developed algorithm in patients with DS. The readers failed to consistently choose the same vertebral level for Cobb angle measurement, whereas the automatic approach ensures the maximum angle is consistently measured. CLINICAL RELEVANCE STATEMENT: Our AI-based algorithm offers reliable Cobb angle measurement on routine MRI for degenerative scoliosis patients, potentially reducing the reliance on conventional radiographs, ensuring consistent assessments, and therefore improving patient care. KEY POINTS: • While often available, MRI images are rarely utilized to determine the severity of degenerative scoliosis. • The presented MRI Cobb angle algorithm is more reliable than humans in patients with degenerative scoliosis. • Radiographic imaging for Cobb angle measurements is mitigated when lumbar MRI images are available.

Factors Predicting Clinically Relevant Pain Relief After Spinal Cord Stimulation for Patients With Chronic Low Back and/or Leg Pain: A Systematic Review With Meta-Analysis and Meta-Regression.

RATIONALE: To optimize results with spinal cord stimulation (SCS) for chronic low back pain (CLBP) and/or leg pain, including persistent spinal pain syndrome (PSPS), careful patient selection based on proved predictive factors is essential. Unfortunately, the necessary selection process required to optimize outcomes of SCS remains challenging. OBJECTIVE: This review aimed to evaluate predictive factors of clinically relevant pain relief after SCS for patients with CLBP and/or radicular leg pain, including PSPS. MATERIALS AND METHODS: In August 2023, PubMed, Cinahl, Cochrane, and EMBASE were searched to identify studies published between January 2010 and August 2023. Studies reporting the percentage of patients with ≥50% pain relief after SCS in patients with CLBP and leg pain, including PSPS at 12 or 24 months, were included. Meta-analysis was conducted to pool results for back, leg, and general pain relief. Predictive factors for pain relief after 12 months were examined using univariable and multivariable meta-regression. RESULTS: A total of 27 studies (2220 patients) were included for further analysis. The mean percentages of patients with substantial pain relief were 68% for leg pain, 63% for back pain, and 73% for general pain at 12 months follow-up, and 63% for leg pain, 59% for back pain, and 71% for general pain at 24 months follow-up assessment. The implantation method and baseline Oswestry Disability Index made the multivariable meta-regression model for ≥50% back pain relief. Sex and pain duration made the final model for ≥50% leg pain relief. Variable stimulation and implantation method made the final model for general pain relief. CONCLUSIONS: This review supports SCS as an effective pain-relieving treatment for CLBP and/or leg pain, and models were developed to predict substantial back and leg pain relief. To provide high-grade evidence for predictive factors, SCS studies of high quality are needed in which standardized factors predictive of SCS success, based on in-patient improvements, are monitored and reported.

Mapping Oswestry Disability Index Responses to EQ-5D-3L Utility Values: Are Cost-Utility Results Valid?

OBJECTIVES: To develop and validate approaches for mapping Oswestry Disability Index responses to 3-level version of EQ-5D utility values and to evaluate the impact of using mapped utility values on cost-utility results compared with published regression models. METHODS: Three response mapping approaches were developed in a random sample of 70% of 18 692 patients with low back pain: nonparametric approach (Non-p), nonparametric approach excluding logical inconsistencies (Non-peLI), and ordinal logistic regression (OLR). Performance was assessed in the remaining 30% using R-square (R2), root mean square error (RMSE), and mean absolute error (MAE). To evaluate whether MAEs and their 95% limits of agreement (LA) were clinically relevant, a minimally clinically important difference of 0.074 was used. Probabilities of cost-effectiveness estimated using observed and mapped utility values were compared in 2 economic evaluations. RESULTS: The Non-p performed the best (R2 = 0.43; RMSE = 0.22; MAE = 0.03; 95% LA = -0.40 to 0.47) compared with the Non-peLI (R2 = 0.07; RMSE = 0.29; MAE = -0.15; 95% LA = -0.63 to 0.34) and OLR (R2 = 0.22; RMSE = 0.26; MAE = 0.02; 95% LA = -0.49 to 0.53). MAEs were lower than the minimally clinically important difference for the Non-p and OLR but not for the Non-peLI. Differences in probabilities of cost-effectiveness ranged from 1% to 4% (Non-p), 0.1% to 9% (Non-peLI), and 0.1% to 20% (OLR). CONCLUSIONS: Results suggest that the developed response mapping approaches are not valid for estimating individual patients' 3-level version of EQ-5D utility values, and-depending on the approach-may considerably affect cost-utility results. The developed approaches did not perform better than previously published regression-based models and are therefore not recommended for use in economic evaluations.

MRI image features with an evident relation to low back pain: a narrative review.

PURPOSE: Low back pain (LBP) is one of the most prevalent health condition worldwide and responsible for the most years lived with disability, yet the etiology is often unknown. Magnetic resonance imaging (MRI) is frequently used for treatment decision even though it is often inconclusive. There are many different image features that could relate to low back pain. Conversely, multiple etiologies do relate to spinal degeneration but do not actually cause the perceived pain. This narrative review provides an overview of all possible relevant features visible on MRI images and determines their relation to LBP. METHODS: We conducted a separate literature search per image feature. All included studies were scored using the GRADE guidelines. Based on the reported results per feature an evidence agreement (EA) score was provided, enabling us to compare the collected evidence of separate image features. The various relations between MRI features and their associated pain mechanisms were evaluated to provide a list of features that are related to LBP. RESULTS: All searches combined generated a total of 4472 hits of which 31 articles were included. Features were divided into five different categories:'discogenic', 'neuropathic','osseous', 'facetogenic', and'paraspinal', and discussed separately. CONCLUSION: Our research suggests that type I Modic changes, disc degeneration, endplate defects, disc herniation, spinal canal stenosis, nerve compression, and muscle fat infiltration have the highest probability to be related to LBP. These can be used to improve clinical decision-making for patients with LBP based on MRI.

Can EQ-5D-3L utility values of low back pain patients be validly predicted by the Oswestry Disability Index for use in cost-effectiveness analyses?

PURPOSE: To assess whether regression modeling can be used to predict EQ-5D-3L utility values from the Oswestry Disability Index (ODI) in low back pain (LBP) patients for use in cost-effectiveness analysis. METHODS: EQ-5D-3L utility values of LBP patients were estimated using their ODI scores as independent variables using regression analyses, while adjusting for case-mix variables. Six different models were estimated: (1) Ordinary Least Squares (OLS) regression, with total ODI score, (2) OLS, with ODI item scores as continuous variables, (3) OLS, with ODI item scores as ordinal variables, (4) Tobit model, with total ODI score, (5) Tobit model, with ODI item scores as continuous variables, and (6) Tobit model, with ODI item scores as ordinal variables. The models' performance was assessed using explained variance (R2) and root mean squared error (RMSE). The potential impact of using predicted instead of observed EQ-5D-3L utility values on cost-effectiveness outcomes was evaluated in two empirical cost-effectiveness analysis. RESULTS: Complete individual patient data of 18,692 low back pain patients were analyzed. All models had a more or less similar R2 (range 45-52%) and RMSE (range 0.21-0.22). The two best performing models produced similar probabilities of cost-effectiveness for a range of willingness-to-pay (WTP) values compared to those based on the observed EQ-5D-3L values. For example, the difference in probabilities ranged from 2 to 5% at a WTP of 50,000 €/QALY gained. CONCLUSION: Results suggest that the ODI can be validly used to predict low back pain patients' EQ-5D-3L utility values and QALYs for use in cost-effectiveness analyses.

Pulmonary symptoms in adolescent idiopathic scoliosis: a systematic review to identify patient-reported and clinical measurement instruments.

STUDY DESIGN: Systematic review. PURPOSE: Adolescent idiopathic scoliosis (AIS) is a deformity of the trunk and chest and can cause a spectrum of pulmonary symptoms. However, no standardized measurement instrument exists. The aim of this systematic review is to identify and describe patient-reported and clinical measurement instruments used to evaluate pulmonary symptoms in patients with AIS. METHODS: Studies published after 01.01.2000 were included in a systematic search. Patient-reported outcome measures (PROMs) and clinical measurement instruments for pulmonary symptoms were extracted as well as their measurement properties (floor-ceiling effects, validity, reliability, responsivity and interpretability). The Risk of Bias (RoB) was evaluated. RESULTS: Out of 3146 studies, 122 were eligible for inclusion. Seven clinical measurement instruments, measuring 50 measurement parameters, were identified. Five PROMs for pulmonary symptoms were identified. Studies assessing the quality of measurement properties in the AIS population were not identified. As such, the RoB could not be determined. CONCLUSION: No available adequate patent centric instruments were identified that measure pulmonary functioning and symptoms. Although clinical measurement instruments are regularly used, their use in routine practice does not seem feasible. The measurement properties of some identified PROMs seem promising; however, they have not been validated in an AIS population. As pulmonary symptoms in patients with AIS are still poorly understood, the development of such a construct and potentially a subsequent PROM to routinely measure pulmonary functioning and patient experience is recommended.

Non-surgical treatment for adult spinal deformity: results of an intensive combined physical and psychological programme for patients with adult spinal deformity and chronic low back pain-a treatment-based cohort study.

OBJECTIVES: No evidence-based treatment exists for adult spinal deformity (ASD) patients with chronic low back pain (CLBP). AIM OF THIS STUDY: evaluate a combined physical and psychological programme (CPPP) for ASD patients with CLBP and to compare this with a non-ASD-cohort with CLBP. METHODS: Data were extracted from the database of CLBP-patients for whom surgery is not an option and completed CPPP. Two cohorts were selected: an ASD-cohort (n = 80) based on a Cobb angle of > 10° and a consecutive age- and gender-matched non-ASD-cohort (n = 240). PRIMARY OUTCOME: functional status (Oswestry Disability Index; ODI). SECONDARY OUTCOMES: pain intensity, self-efficacy and quality of life. ASSESSMENTS: pre and post treatment, one-month and one-year follow-up (FU). CLINICAL RELEVANCE: minimal important clinical change (MCIC; ODI 10 points), patient acceptable symptom state (PASS; ODI ≤ 22). RESULTS: Demographics ASD-cohort: 79% female, mean age 50.9 (± 14.1) years, mean CLBP duration 15.5 (± 12.5) years, mean Cobb angle 21.4 (± 9.4)°. Non-ASD-cohort: not significantly different. Both cohorts improved in functional status (F[1,318] = 142.982, p < .001; r = 0.31). The ASD-cohort improved from mean ODI 39.5(± 12.0) at baseline to mean ODI 31.8(± 16.5) at one-year FU. CLINICAL RELEVANCE: 51% of the ASD patients reached MCIC and 33% reached a PASS. An interaction effect is shown between time and both cohorts (F[1,318] = 8.2, p = .004; r = 0.03); however, not clinically relevant. All secondary outcomes: improvement at one-year FU. CONCLUSION: This is the first study showing beneficial outcomes of a non-surgical treatment in selected ASD patients with longstanding CLBP. Improvement is shown in functional status, and appeared equivalent to the non-ASD cohort. LEVEL OF EVIDENCE 1: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Standard set of network outcomes for traumatic spinal cord injury: a consensus-based approach using the Delphi method.

STUDY DESIGN: Consensus study. OBJECTIVES: The purpose of this study is to define a standardized (network) outcomes set for traumatic spinal cord injury (t-SCI), covering the patient journey from acute to chronic rehabilitation phase, including patient-relevant outcomes, adequate measurement instruments, as well as case-mix and risk factors. SETTING: Acute Spinal Cord Injury (ASCI) Unit Nijmegen, the Netherlands. METHODS: A modified Delphi method was performed, including a multidisciplinary panel of 19 health-care professionals with experience in t-SCI management. Formal consensus was reached after two web-based surveys, a face-to-face meeting, and a final confirmation round (threshold consensus: 70%). RESULTS: In the first two Delphi rounds, 18/19 invited panelists (94.7%) responded and 10 panelists participated in the final meeting. The prefinal set was confirmed by all panelists. The standard set encompasses the three-tiered outcome hierarchy and consists of patient-reported and clinician-reported outcome domains and measurement instruments. Consensus was reached to include survival, degree of health or recovery, time to recovery, and return to normal activities, disutility of care or treatment process, sustainability of health and nature of recurrences, and long-term consequences of therapy. A measurement schedule was defined as well as for proposed casemix and risk factors, including demographics, clinical status, and treatment process. CONCLUSION: A standard set of network outcomes is developed that could be implemented in hospitals and rehabilitation centers involved in the treatment of t-SCI. Using this standard set, comparison of the quality of care is possible and prognostic prediction of outcomes of treatment is feasible, so that each patient receives the right care at the right time in the right place.

Evaluation and Validation of the Dutch European Foot and Ankle Society (EFAS) Score.

The European Foot and Ankle Society (EFAS) score is a recently developed foot and ankle patient-reported outcome measure. It has been developed and partly validated in seven languages. This study's aim was to investigate the measurement properties of the Dutch version of the EFAS score. Subscales of the Dutch EFAS score were evaluated in 547 patients with a variety of foot and ankle diagnoses. Floor and ceiling effect, reliability, and construct validity were assessed. The internal consistency of the EFAS score was acceptable (Cronbach's alpha 0.79-0.94). Repeatability was considered poor, with intraclass correlation coefficients between 0.32 and 0.39. Construct validity was inadequate with confirmation of 67% of the hypothesized correlations. In conclusion, the Dutch version of the EFAS score does not have adequate measurement properties for use in patient with patients with varying foot and ankle problems.

No added value of 2-year radiographic follow-up of fusion surgery for adolescent idiopathic scoliosis.

PURPOSE: For fusion surgery in adolescent idiopathic scoliosis (AIS) consensus exists that a 2-year radiographic follow-up assessment is needed. This standard lacks empirical evidence. The purpose of this study was to investigate the radiographic follow-up after corrective surgery in AIS, from pre-until 2 years postoperative. METHODS: In this historical cohort study, 63 patients surgically treated for AIS, age ≤ 25 years, with 2-year radiographic follow-up, were enrolled. The primary outcome measure was the major Cobb angle. Secondary outcomes were coronal and sagittal spino-pelvic parameters, including proximal junction kyphosis (PJK) and distal adding-on. Change over time was analyzed using a repeated measures ANOVA. RESULTS: The major curve Cobb angle showed a statistically significant change for pre- to 1 year postoperative, but not for 1- to 2-year follow-up. Seven out of 63 patients did show a change exceeding the error of measurement (5°) from 1- to 2-year follow-up (range -8° to +7°), of whom 2 patients showed curve progression and 5 showed improvement. PJK or distal adding-on was not observed. CONCLUSIONS: No statistically significant changes in major curve Cobb angle were found during postsurgical follow-up, or in adjacent non-fused segments. The findings of this study are not supportive for routine radiographs 2 years after fusion surgery in AIS patients.

Targeting self-efficacy more important than dysfunctional behavioral cognitions in patients with longstanding chronic low back pain; a longitudinal study.

BACKGROUND: Multidisciplinary pain management programs based on cognitive behavioral training (CBT) principles have been shown moderately effective in improving daily functioning in patients with chronic low back pain (CLBP). To optimize health-related outcomes as daily functioning, a clear understanding of the working mechanisms of these programs is warranted. Being confident to achieve a desired outcome, i.e. self-efficacy, is suggested to be a more potent determinant for beneficial treatment outcomes than restructuring the patient's dysfunctional behavioral cognitions (pain catastrophizing and fear of movement [FoM]), but the evidence is scarce. The objective of this study was twofold: 1) to determine whether a two-week pain management program resulted in post-treatment improvements in self-efficacy and decreased dysfunctional behavioral cognitions in patients with CLBP, and 2) to examine the unique contribution of self-efficacy to improvement in post-treatment disability. METHODS: A secondary analysis of an historical cohort study was performed, including 524 patients (59% females). PRIMARY OUTCOME: functional status (Oswestry Disability Index v2.1a). SECONDARY OUTCOMES: catastrophizing (Pain Catastrophizing Scale), FoM (Tampa Scale for Kinesiophobia), and self-efficacy (Pain Self-Efficacy Questionnaire). ASSESSMENTS: pre-, post-treatment, 1, and 12-months follow-up. Paired Student's t-tests were applied and clinical relevancy of improvements was described using minimal clinical important changes. Adjusted multivariate linear regression analyses were performed to explore the unique contribution of self-efficacy. RESULTS: The mean age of patients was 46 (SD = 9.5) years and they had longstanding CLBP (mean 12.5 [SD = 10.8] years). Mean functional status, self-efficacy, and dysfunctional behavioral cognitions improved significantly at post-treatment, with improvements maintained at 12 months follow-up. Post-treatment relevant improvements in self-efficacy and dysfunctional behavioral cognitions ranged from 62.4% (FoM) to 68.7% (self-efficacy). Post-treatment self-efficacy improved the model explaining post-treatment functional disability (basic model R2 = 0.49, F(6,517) = 83.67, p < 0.001; final model R2 = 0.57, F(8,515) = 85.20, p < 0.001). This was further substantiated by the relative contribution (standardized betas) of self-efficacy: 5.67 times more than catastrophizing and 9.75 times more than FoM. CONCLUSIONS: Targeting self-efficacy contributes to fast improvement in functional status for selected and motivated patients with persistent CLBP. In pain management programs and (online) self-management programs for CLBP, targeting patients' self-efficacy should have a prominent place.

Good results at 2-year follow-up of a custom-made triflange acetabular component for large acetabular defects and pelvic discontinuity: a prospective case series of 50 hips.

Background and purpose - Custom triflange acetabular components (CTACs) are suggested as good solutions for large acetabular defects in revision total hip arthroplasty. However, high complication rates have been reported and most studies are of limited quality. This prospective study evaluates the performance of a CTAC in patients with large acetabular defects including pelvic discontinuity.Patients and methods - Prospectively collected data of 49 consecutive patients (50 hips), who underwent an acetabular revision with a CTAC were analyzed. Follow-up (FU) was 2 years. The median age of the patients was 68 years (41-89) and 41 were women. Primary outcomes were re-revision of the CTAC and differences between the modified Oxford Hip Score (mOHS) preoperatively and at 2-year follow-up. Secondary outcomes included several patient-reported outcomes (PROMs), radiological results, complications, and a comparison between hips with and without pelvic discontinuity (PD).Results - 1 patient (1 hip) was lost to the 2-year FU. No CTAC needed re-revision. The preoperative and 2-year FU mOHS were available in 40 hips and improved statistically significantly. All of the other secondary outcomes improved over time. 5 hips (of 45 with radiological 2-year FU) had loosening of screws. 8 hips had complications, including 3 persistent wound leakage, 3 pelvic fractures, and 1 dislocation. The mOHS and complication rate were similar in hips with and without PD.Interpretation - Reconstruction of large acetabular defects with and without PD with this CTAC showed good improvement in patient-reported daily functioning, high patient-reported satisfaction, few complications, and no re-revisions at 2-year FU.

Effectiveness of surgery for sciatica with disc herniation is not substantially affected by differences in surgical incidences among three countries: results from the Danish, Swedish and Norwegian spine registries.

PURPOSE: Yearly incidence of surgery for symptomatic lumbar disc herniation varies and is 29/100,000 in Sweden, 46/100,000 in Denmark and 58/100,000 in Norway. This variation was used to study whether differences in surgical incidence were associated with differences in preoperative patient characteristics as well as patient-reported outcomes. METHODS: Data from the national spine registers in Sweden, Denmark and Norway during 2011-2013 were pooled, and 9965 individuals, aged 18-65 years, of which 6468 had one-year follow-up data, were included in the study. Both absolute and case-mix-adjusted comparisons of the primary outcome Oswestry Disability Index (ODI) and the secondary outcomes EQ-5D-3L, and Numerical Rating Scale (NRS) for leg and back pain were performed. Case-mix adjustment was done for baseline age, sex, BMI, smoking, co-morbidity, duration of leg pain and preoperative value of the dependent variable. RESULTS: Mean improvement in the outcome variables exceeded previously described minimal clinical important change in all countries. Mean (95% CI) final scores of ODI were 18 (17-18), 19 (18-20) and 15 (15-16) in Sweden, Denmark and Norway, respectively. Corresponding results of EQ-5D-3L were 0.74 (0.73-0.75), 0.73 (0.72-0.75) and 0.75 (0.74-0.76). Results of NRS leg and back pain behaved similarly. Case-mix adjustment did not alter the findings substantially. CONCLUSION: We found no clear association between incidence of surgery for lumbar disc herniation and preoperative patient characteristics as well as outcome, and the differences between the countries were lower than the minimal clinical important difference in all outcomes. These slides can be retrieved under Electronic Supplementary Material.

Which patient-reported factors predict referral to spinal surgery? A cohort study among 4987 chronic low back pain patients.

PURPOSE: It is unknown which chronic low back pain (CLBP) patients are typically referred to spinal surgery. The present study, therefore, aimed to explore which patient-reported factors are predictive of spinal surgery referral among CLBP patients. METHODS: CLBP patients were consecutively recruited from a Dutch orthopedic hospital specialized in spine care (n = 4987). The outcome of this study was referral to spinal surgery (yes/no), and was assessed using hospital records. Possible predictive factors were assessed using a screening questionnaire. A prediction model was constructed using logistic regression, with backwards selection and p < 0.10 for keeping variables in the model. The model was internally validated and evaluated using discrimination and calibration measures. RESULTS: Female gender, previous back surgery, high intensity leg pain, somatization, and positive treatment expectations increased the odds of being referred to spinal surgery, while being obese, having comorbidities, pain in the thoracic spine, increased walking distance, and consultation location decreased the odds. The model's fit was good (X 2 = 10.5; p = 0.23), its discriminative ability was poor (AUC = 0.671), and its explained variance was low (5.5%). A post hoc analysis indicated that consultation location was significantly associated with spinal surgery referral, even after correcting for case-mix variables. CONCLUSION: Some patient-reported factors could be identified that are predictive of spinal surgery referral. Although the identified factors are known as common predictive factors of surgery outcome, they could only partly predict spinal surgery referral.

Measuring outcomes in adult spinal deformity surgery: a systematic review to identify current strengths, weaknesses and gaps in patient-reported outcome measures.

PURPOSE: Adult spinal deformity (ASD) causes severe disability, reduces overall quality of life, and results in a substantial societal burden of disease. As healthcare is becoming more value based, and to facilitate global benchmarking, it is critical to identify and standardize patient-reported outcome measures (PROMs). This study aims to identify the current strengths, weaknesses, and gaps in PROMs used for ASD. METHODS: Studies were included following a systematic search in multiple bibliographic databases between 2000 and 2015. PROMs were extracted and linked to the outcome domains of WHO's International Classification of Functioning and Health (ICF) framework. Subsequently, the clinimetric quality of identified PROMs was evaluated. RESULTS: The literature search identified 144 papers that met the inclusion criteria, and nine frequently used PROMs were identified. These covered 29 ICF outcome domains, which could be grouped into three of the four main ICF chapters: body function (n = 7), activity and participation (n = 19), environmental factors (n = 3), and body structure (n = 0). A low quantity (n = 3) of papers was identified that studied the clinimetric quality of PROMs. The Scoliosis Research Society (SRS)-22 has the highest level of clinimetric quality for ASD. CONCLUSIONS: Outcome domains related to mobility and pain were well represented. We identified a gap in current outcome measures regarding neurological and pulmonary function. In addition, no outcome domains were measured in the ICF chapter body structure. These results will serve as a foundation for the process of seeking international consensus on a standard set of outcome domains, accompanied PROMs and contributing factors to be used in future clinical trials and spine registries.

Low sensitivity of implant sonication when screening for infection in revision surgery.

Background and purpose - Prosthetic-joint infection (PJI) is the most serious complication of arthroplasty, and accurate identification of a potentially responsible microorganism is essential for successful antibiotic treatment. We therefore determined the diagnostic accuracy of sonication and compared it with tissue culture as a screening tool in detecting prosthetic joint infection in revision arthroplasty. Patients and methods - 252 consecutive revision arthroplasty cases were enrolled. These cases were determined as being suspected or unsuspected of having infection according to standard criteria. Perioperatively, 6 periprosthetic interface tissue biopsies were obtained from each patient and the implants removed were sonicated. The sensitivity and specificity of periprosthetic tissue culture and sonication fluid cultures were determined. Results - Preoperatively, 75 revision cases were classified as having PJI (33 early and 42 late) and 177 were unsuspected of having infection. Compared with tissue culture, the sensitivity of the sonication fluid analysis was low: 0.47 (95% CI: 0.35-0.59) for sonication as compared to 0.68 (95% CI: 0.56-0.78) for tissue culture. The specificity of the sonication fluid analysis was higher than that for tissue culture: 0.99 (95% CI: 0.96-1.0) as compared to 0.80 (95% CI: 0.74-0.86). Interpretation - Sonication is a highly specific test for diagnosis of PJI. However, due to the low sensitivity, a negative sonication result does not rule out the presence of PJI. Thus, sonication is not of value for screening of microorganisms during revision surgery.

Defining a core outcome set for adolescent and young adult patients with a spinal deformity.

Background and purpose - Routine outcome measurement has been shown to improve performance in several fields of healthcare. National spine surgery registries have been initiated in 5 Nordic countries. However, there is no agreement on which outcomes are essential to measure for adolescent and young adult patients with a spinal deformity. The aim of this study was to develop a core outcome set (COS) that will facilitate benchmarking within and between the 5 countries of the Nordic Spinal Deformity Society (NSDS) and other registries worldwide. Material and methods - From August 2015 to September 2016, 7 representatives (panelists) of the national spinal surgery registries from each of the NSDS countries participated in a modified Delphi study. With a systematic literature review as a basis and the International Classification of Functioning, Disability and Health framework as guidance, 4 consensus rounds were held. Consensus was defined as agreement between at least 5 of the 7 representatives. Data were analyzed qualitatively and quantitatively. Results - Consensus was reached on the inclusion of 13 core outcome domains: "satisfaction with overall outcome of surgery", "satisfaction with cosmetic result of surgery", "pain interference", physical functioning", "health-related quality of life", "recreation and leisure", "pulmonary fatigue", "change in deformity", "self-image", "pain intensity", "physical function", "complications", and "re-operation". Panelists agreed that the SRS-22r, EQ-5D, and a pulmonary fatigue questionnaire (yet to be developed) are the most appropriate set of patient-reported measurement instruments that cover these outcome domains. Interpretation - We have identified a COS for a large subgroup of spinal deformity patients for implementation and validation in the NSDS countries. This is the first study to further develop a COS in a global perspective.

De novo degenerative lumbar scoliosis: a systematic review of prognostic factors for curve progression.

PURPOSE: To identify prognostic factors for curve progression in de novo degenerative lumbar scoliosis (DNDLS) by performing a systematic review of the literature. METHODS: Studies were selected for inclusion following a systematic search in the bibliographic databases PubMed and EMBASE prior to September 2015 and hand searches of the reference lists of retrieved articles. Two authors independently assessed methodological quality. Data were extracted and presented according to a best evidence synthesis. RESULTS: The literature search generated a total of 2696 references. After removing duplicates and articles that did not meet inclusion criteria, 12 studies were included. Due to the lack of statistical analyses, pooling of data was not possible. Strong evidence indicates that increasing intervertebral disk degeneration, lateral vertebral translation ≥6 mm, and an intercrest line through L5 (rather than L4) are associated with DNDLS curve progression. Moderate evidence suggests that apical vertebral rotation Grade II or III is associated with curve progression. For the majority of other prognostic factors, we found limited, conflicting, or inconclusive evidence. Osteoporosis, a coronal Cobb angle <30°, lumbar lordosis, lateral osteophytes difference of ≥5 mm, and degenerative spondylolisthesis have not been shown to be risk factors. Clinical risk factors for progression were not identified. CONCLUSIONS: This review shows strong evidence that increased intervertebral disk degeneration, an intercrest line through L5, and apical lateral vertebral translation ≥6 mm are associated with DNDLS curve progression. Moderate evidence was found for apical vertebral rotation (Grade II/III) as a risk factor for curve progression. These results, however, may not be directly applicable to the individual patient.

Treatment of prosthetic joint infections due to Propionibacterium. Similar results in 60 patients treated with and without rifampicin.

BACKGROUND AND PURPOSE: Currently, Propionibacterium is frequently recognized as a causative microorganism of prosthetic joint infection (PJI). We assessed treatment success at 1- and 2-year follow-up after treatment of Propionibacterium-associated PJI of the shoulder, hip, and knee. Furthermore, we attempted to determine whether postoperative treatment with rifampicin is favorable. PATIENTS AND METHODS: We conducted a retrospective cohort study in which we included patients with a primary or revision joint arthroplasty of the shoulder, hip, or knee who were diagnosed with a Propionibacterium-associated PJI between November 2008 and February 2013 and who had been followed up for at least 1 year. RESULTS: We identified 60 patients with a Propionibacterium-associated PJI with a median duration of 21 (0.1-49) months until the occurrence of treatment failure. 39 patients received rifampicin combination therapy, with a success rate of 93% (95% CI: 83-97) after 1 year and 86% (CI: 71-93) after 2 years. The success rate was similar in patients who were treated with rifampicin and those who were not. INTERPRETATION: Propionibacterium-associated PJI treated with surgery in combination with long-term antibiotic administration had a successful outcome at 1- and 2-year follow-up irrespective of whether the patient was treated with rifampicin. Prospective studies are needed to determine whether the use of rifampicin is beneficial in the treatment of Propionibacterium-associated PJI.

Mobile bearing vs fixed bearing prostheses for posterior cruciate retaining total knee arthroplasty for postoperative functional status in patients with osteoarthritis and rheumatoid arthritis.

BACKGROUND: It is unclear whether there are differences in benefits and harms between mobile and fixed prostheses for total knee arthroplasty (TKA). The previous Cochrane review published in 2004 included two articles. Many more trials have been performed since then; therefore an update is needed. OBJECTIVES: To assess the benefits and harms of mobile bearing compared with fixed bearing cruciate retaining total knee arthroplasty for functional and clinical outcomes in patients with osteoarthritis (OA) or rheumatoid arthritis (RA). SEARCH METHODS: We searched The Cochrane Library, PubMed, EMBASE, CINAHL and Web of Science up to 27 February 2014, and the trial registers ClinicalTrials.gov, Multiregister, Current Controlled Trials and the World Health Organization (WHO) International Clinical Trials Registry Platform for data from unpublished trials, up to 11 February 2014. We also screened the reference lists of selected articles. SELECTION CRITERIA: We selected randomised controlled trials comparing mobile bearing with fixed bearing prostheses in cruciate retaining TKA among patients with osteoarthritis or rheumatoid arthritis, using functional or clinical outcome measures and follow-up of at least six months. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures as expected by The Cochrane Collaboration. MAIN RESULTS: We found 19 studies with 1641 participants (1616 with OA (98.5%) and 25 with RA (1.5%)) and 2247 knees. Seventeen new studies were included in this update.Quality of the evidence ranged from moderate (knee pain) to low (other outcomes). Most studies had unclear risk of bias for allocation concealment, blinding of participants and personnel, blinding of outcome assessment and selective reporting, and high risk of bias for incomplete outcome data and other bias. Knee painWe calculated the standardised mean difference (SMD) for pain, using the Knee Society Score (KSS) and visual analogue scale (VAS) in 11 studies (58%) and 1531 knees (68%). No statistically significant differences between groups were reported (SMD 0.09, 95% confidence interval (CI) -0.03 to 0.22, P value 0.15). This represents an absolute risk difference of 2.4% points higher (95% CI 0.8% lower to 5.9% higher) on the KSS pain scale and a relative percent change of 0.22% (95% CI 0.07% lower to 0.53% higher). The results were homogeneous. Clinical and functional scores The KSS clinical score did not differ statistically significantly between groups (14 studies (74%) and 1845 knees (82%)) with a mean difference (MD) of -1.06 points (95% CI -2.87 to 0.74, P value 0.25) and heterogeneous results. KSS function was reported in 14 studies (74%) with 1845 knees (82%) as an MD of -0.10 point (95% CI -1.93 to 1.73, P value 0.91) and homogeneous results. In two studies (11%), the KSS total score was favourable for mobile bearing (159 vs 132 for fixed bearing), with MD of -26.52 points (95% CI -45.03 to -8.01, P value 0.005), but with a wide 95% confidence interval indicating uncertainty about the estimate.Other reported scoring systems did not show statistically significant differences: Hospital for Special Surgery (HSS) score (seven studies (37%) in 1021 knees (45%)) with an MD of -1.36 (95% CI -4.18 to 1.46, P value 0.35); Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score (two studies (11%), 167 knees (7%)) with an MD of -4.46 (95% CI -16.26 to 7.34, P value 0.46); and Oxford total (five studies (26%), 647 knees (29%) with an MD of -0.25 (95% CI -1.41 to 0.91, P value 0.67). Health-related quality of lifeThree studies (16%) with 498 knees (22%) reported on health-related quality of life, and no statistically significant differences were noted between the mobile bearing and fixed bearing groups. The Short Form (SF)-12 Physical Component Summary had an MD of -1.96 (95% CI -4.55 to 0.63, P value 0.14) and heterogeneous results. Revision surgeryTwenty seven revisions (1.3%) were performed in 17 studies (89%) with 2065 knees (92%). In all, 13 knees were revised in the fixed bearing group and 14 knees in the mobile bearing group. No statistically significant differences were found (risk difference 0.00, 95% CI -0.01 to 0.01, P value 0.58), and homogeneous results were reported. MortalityIn seven out of 19 studies, 13 participants (37%) died. Two of these participants had undergone bilateral surgery, and for seven participants, it was unclear which prosthesis they had received; therefore they were excluded from the analyses. Thus our analysis included four out of 191 participants (2.1%) who had died: one in the fixed bearing group and three in the mobile bearing group. No statistically significant differences were found. The risk difference was -0.02 (95% CI -0.06 to 0.03, P value 0.49) and results were homogeneous. Reoperation ratesThirty reoperations were performed in 17 studies (89%) with 2065 knees (92%): 18 knees in the fixed bearing group (of the 1031 knees) and 12 knees in the mobile group (of the 1034 knees). No statistically significant differences were found. The risk difference was -0.01 (95% CI -0.01 to 0.01, P value 0.99) with homogeneous results. Other serious adverse eventsSixteen studies (84%) reported nine other serious adverse events in 1735 knees (77%): four in the fixed bearing group (of the 862 knees) and five in the mobile bearing group (of the 873 knees). No statistically significant differences were found (risk difference 0.00, 95% CI -0.01 to 0.01, P value 0.88), and results were homogeneous. AUTHORS' CONCLUSIONS: Moderate- to low-quality evidence suggests that mobile bearing prostheses may have similar effects on knee pain, clinical and functional scores, health-related quality of life, revision surgery, mortality, reoperation rate and other serious adverse events compared with fixed bearing prostheses in posterior cruciate retaining TKA. Therefore we cannot draw firm conclusions. Most (98.5%) participants had OA, so the findings primarily reflect results reported in participants with OA. Future studies should report in greater detail outcomes such as those presented in this systematic review, with sufficient follow-up time to allow gathering of high-quality evidence and to inform clinical practice. Large registry-based studies may have added value, but they are subject to treatment-by-indication bias. Therefore, this systematic review of RCTs can be viewed as the best available evidence.