12-Year clinical and radiological results of a double-blind randomized controlled trial comparing posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty.

BACKGROUND: A subject of ongoing debate among orthopedic surgeons is the importance of preserving the posterior cruciate ligament in total knee arthroplasty (TKA), but long-term survival studies are scarce. The aim of this study was to compare long-term survival rates, and clinical and radiological follow up of a double-blind randomized controlled trial comparing posterior cruciate-retaining (PCR) versus posterior-stabilizing (PS) implant design of an AGC TKA. METHODS: A total of 114 patients were included in the survival analysis (PCR n = 61; PS n = 53). Forty-five patients (PCR n = 25; PS n = 20) participated in the long-term follow up using patient-reported outcome measures (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short-Form Health Survey (SF-36) and Kujala score (measuring anterior knee pain)). Thirty-one patients were assessed with a physical test (Knee Society Score (KSS)) and radiographs. RESULTS: Overall survival rate was 95.6% (PCR 98.4% vs. PS 92.5%), with five patients having a major revision (PCR n = 1 vs. PS n = 4, respectively). Satisfying outcome scores for both groups were described at on average 12-year follow up with no significant differences in KSS knee and function scores, WOMAC, SF-36, or Kujala scores between groups. Radiographically, there were no findings of femoral or tibial loosening or polyethylene wear in either group. CONCLUSIONS: Good long-term survival rates were described for the PCR and the PS design of an AGC TKA. There were no significant differences in clinical and radiological outcomes between a PCR and a PS design 12 years postoperatively.

The SNAP Trial: 2-Year Results of a Double-Blind Multicenter Randomized Controlled Trial of a Silicon Nitride Versus a PEEK Cage in Patients After Lumbar Fusion Surgery.

STUDY DESIGN: Randomized controlled trial. OBJECTIVES: Lumbar interbody fusion with cages is performed to provide vertebral stability, restore alignment, and maintain disc and foraminal height. Polyetheretherketone (PEEK) is commonly used. Silicon nitride (Si3N4) is an alternative material with good osteointegrative properties. This study was designed to assess if Si3N4 cages perform similar to PEEK. METHODS: A non-inferiority double-blind multicenter RCT was designed. Patients presenting with chronic low-back pain with or without leg pain were included. Single- or double-level instrumented transforaminal lumbar interbody fusion (TLIF) using an oblique PEEK or Si3N4 cage was performed. The primary outcome was the Roland-Morris Disability Questionnaire (RMDQ). The non-inferiority margin for the RMDQ was 2.6 points on a scale of 24. Secondary outcomes included the Oswestry Disability Questionnaire (ODI), Visual Analogue Scales (VAS), SF-36 Physical Function, patient and surgeon Likert scores, radiographic evaluations for subsidence, segmental motion, and fusion. Follow-up was planned at 3, 6, 12, and 24-months. RESULTS: Ninety-two patients were randomized (i.e. 48 to PEEK and 44 to Si3N4). Both groups showed good clinical improvements on the RMDQ scores of up to 5-8 points during follow-up. No statistically significant differences were observed in clinical and radiographic outcomes. Mean operative time and blood loss were statistically significantly higher for the Si3N4 cohort. Although not statistically significant, there was a higher incidence of complications and revisions associated with the Si3N4 cage. CONCLUSIONS: There was insufficient evidence to conclude that Si3N4 was non-inferior to PEEK.

Are the Roland Morris Disability Questionnaire and Oswestry Disability Index interchangeable in patients after lumbar spinal fusion?

BACKGROUND: Low back pain is a common health problem for which there are several treatment options. For optimizing clinical decision making, evaluation of treatments and research purposes it is important that health care professionals are able to evaluate the functional status of patients. Patient reported outcome measures (PROMs) are widely accepted and recommended. The Roland Morris Disability Questionnaire (RMDQ) and the Oswestry Disability Index (ODI) are the two mainly used condition-specific patient reported outcomes. Concerns regarding the content and structural validity and also the different scoring systems of these outcome measures makes comparison of treatment results difficult. OBJECTIVE: Aim of this study was to determine if the RMDQ and ODI could be used exchangeable by assessing the correlation and comparing different measurement properties between the questionnaires. METHODS: Clinical data from patients who participated in a multicenter RCT with 2 year follow-up after lumbar spinal fusion were used. Outcome measures were the RMDQ, ODI, Short Form 36 - Health Survey (SF-36), leg pain and back pain measured on a 0-100 mm visual analogue scale (VAS). Cronbach's alpha coefficients, Spearman correlation coefficients, multiple regression analysis and Bland-Altman plots were calculated. RESULTS: three hundred and seventy-six completed questionnaires filled out by 87 patients were used. The ODI and RMDQ had both a good level of internal consistency. There was a very strong correlation between the RMDQ and the ODI (r= 0.87; p< 0.001), and between the VAS and both the ODI and RMDQ. However, the Bland-Altman plot indicated bad agreement between the ODI and RMDQ. CONCLUSIONS: The RMDQ and ODI cannot be used interchangeably, nor is there a possibility of converting the score from one questionnaire to the other. However, leg pain and back pain seemed to be predictors for both the ODI and the RMDQ.

Surgical Restoration of Sagittal Alignment of the Spine: Correlation with Improved Patient-Reported Outcomes: A Systematic Review and Meta-Analysis.

BACKGROUND: The sagittal-plane curvatures of the human spine are the consequence of evolution from quadrupedalism to bipedalism and are needed to maintain the center of mass of the body within the base of support in the bipedal position. Lumbar degenerative disorders can lead to a decrease in lumbar lordosis and thereby affect overall alignment of the spine. However, there is not yet enough direct evidence that surgical restoration of spinal malalignment would lead to a better clinical outcome. Therefore, the aim of this study was to assess the correlation between patient-reported outcomes and actual obtained spinal sagittal alignment in adult patients with lumbar degenerative disorders who underwent surgical treatment. METHODS: A comprehensive literature search was conducted through databases (PubMed, Cochrane, Web of Science, and Embase). The last search was in November 2018. Risk of bias was assessed with the Newcastle-Ottawa quality assessment scale. A meta-regression analysis was performed. RESULTS: Of 2,024 unique articles in the original search, 34 articles with 973 patients were included. All studies were either retrospective or prospective cohort studies; no randomized controlled trials were available. A total of 54 relations between preoperative-to-postoperative improvement in patient-reported outcome measures (PROMs) and radiographic spinopelvic parameters were found, of which 20 were eligible for meta-regression analysis. Of these, 2 correlations were significant: pelvic tilt (PT) versus Oswestry Disability Index (ODI) (p = 0.009) and PT versus visual analog scale (VAS) pain (p = 0.008). CONCLUSIONS: On the basis of the current literature, lower PT was significantly correlated with improved ODI and VAS pain in patients with sagittal malalignment caused by lumbar degenerative disorders that were treated with surgical correction of the sagittal balance. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.