藤田 順之

BACKGROUND CONTEXT: The Oswestry Disability Index (ODI) is one of the most widely used instruments for assessing disability related to low back pain (LBP). However, population-based normative values are scarce, and the structural validity of Japanese version of the ODI (version 2.1a) has not been sufficiently evaluated. PURPOSE: To psychometrically validate the Japanese version of the ODI (version 2.1a) and to establish population-based normative values stratified by age and LBP duration. STUDY DESIGN/SETTING: Population-based cross-sectional study using a nationwide survey in Japan. PATIENT SAMPLE: A nationally representative sample of community-dwelling adults in Japan selected through a two-stage stratified random sampling design. A total of 5,000 individuals were invited to participate. OUTCOME MEASURES: Self-report measures: Disability related to low back pain assessed using the Japanese version of the ODI (version 2.1a). METHODS: Japan was stratified into 65 strata, from which 250 sampling points were randomly selected, and 20 residents were randomly sampled per point. Psychometric properties of the ODI version 2.1a were evaluated among respondents using factor analyses. Response-adjusted, survey-weighted normative values were estimated for the general population and for individuals with LBP, stratified by age group and pain duration subtype (acute, subacute, and chronic). RESULTS: Of the 5,000 individuals invited, 2,188 responded (response rate 43.8%). Among respondents, 1,270 had complete ODI data and were included in the psychometric analysis, including 173 individuals with LBP. The estimated population prevalence of LBP was 14.7% (95% confidence interval [CI] 13.1-16.4%), comprising acute 2.5% (95% CI 1.9-3.3%), subacute 1.1% (95% CI 0.7-1.7%), and chronic 11.1% (95% CI 9.8-12.5%). Factor analyses demonstrated a unidimensional structure of the ODI version 2.1a. Among individuals with LBP, the survey-weighted mean ODI score was 20.23 (95% CI 18.32-22.13). Normative values varied by pain duration (acute: 12.54 [95% CI 8.87-16.22]; subacute: 13.54 [95% CI 8.78-18.31]; chronic: 22.74 [95% CI 20.56-24.92]) and increased with advancing age. CONCLUSION: This study provides psychometric validation of the Japanese ODI version 2.1a and establishes age- and pain duration-specific normative values. These findings support the use of ODI version 2.1a as a single total score for profiling disability in everyday life and for evaluating the management of LBP in both clinical practice and research.

BACKGROUND: The 25-item Geriatric Locomotive Function Scale (GLFS-25) is often used to assess locomotive syndrome stage in older adults with lumbar spinal stenosis (LSS). However, locomotive syndrome stage three encompasses a wide score range, potentially masking clinically meaningful improvements. This study aimed to establish the minimal clinically important difference (MCID) for the GLFS-25 and determine whether MCID-based assessment better reflects surgical outcomes than stage-based evaluation. METHODS: This study included 314 patients aged 65 years and older with LSS who were preoperatively classified as having locomotive syndrome stage three. Patient-reported outcome measures, including the GLFS-25, the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), and Zurich Claudication Questionnaire (ZCQ), were administered before and at six months and 1 year after surgery. The MCID for the GLFS-25 was calculated using an anchor-based method, with the satisfaction item from the ZCQ at 1 year after surgery serving as the anchor. Patients were then categorized into four groups based on whether they achieved improvements in locomotive syndrome stage and/or the GLFS-25 MCID. RESULTS: A 19-point improvement in the GLFS-25 was determined to be the MCID, with an area under the receiver operating characteristic curve, sensitivity, and specificity of 0.80, 65.8%, and 90.2%, respectively. Based on postoperative changes, 129, 49, 33, and 103 patients achieved both stage and MCID improvement (group C), improvement in MCID alone (group M), improvement in stage alone (group S), and no improvement, respectively. Group C showed significantly better surgical effectiveness across all JOABPEQ domains. Group M showed significant improvements in four domains, whereas group S showed significant improvement in only one domain. CONCLUSIONS: The newly established 19-point MCID for the GLFS-25 more accurately represented clinically meaningful improvement than stage-based evaluation. The combined use of MCID and stage classification may enhance outcome assessment after LSS surgery in older adults.

BACKGROUND: Hip fractures in older adults require surgery and frequently result in prolonged hospital stays. Recently, the revision of Japan's medical reimbursement system introduced an acute care incentive to promote early surgery for hip fracture cases, highlighting the need for timely intervention and efficient inpatient management. In this context, the present study aimed to identify factors associated with prolonged hospital stay in older adults undergoing hip fracture surgery at two acute care hospitals in Japan. METHODS: A retrospective review was conducted on data from 1184 patients aged ≥65 years who underwent hip fracture surgery between April 2021 and March 2024. Patients were categorized into three groups based on their length of stay: ≤14 days (short group), 15-28 days (moderate group), and ≥29 days (long group). Multinomial logistic regression analysis was utilized to identify factors associated with prolonged hospital stays. Receiver operating characteristic curve analysis was conducted to determine the optimal cutoff for preoperative waiting time in predicting a prolonged hospital stay. RESULTS: The short group included 260 patients (22.0%), the moderate group 631 (53.3%), and the long group 293 (24.7%). Multivariable analysis revealed that extended preoperative waiting time and living with others were independently associated with prolonged hospital stay. The odds ratio for being in the long group was 3.62 (95% confidence interval: 2.40-5.46) for a preoperative waiting time of ≥3 days compared with ≤2 days. The optimal cutoff for preoperative waiting time to predict a hospital stay ≥29 days was 2.5 days (area under the curve: 0.68; sensitivity: 62.8%; specificity: 62.5%), highlighting a clear window for surgical intervention. CONCLUSION: The preoperative waiting time was crucial factor influencing the length of hospital stay after hip fracture surgery in older adults. Timely surgical intervention within 2 days of admission can enhance care efficiency and shorten the hospitalization period.

OBJECTIVES: Whether to resurface the patella in total knee arthroplasty for patients with rheumatoid arthritis remains controversial. This study evaluated long-term clinical and radiographic outcomes after total knee arthroplasty without patellar resurfacing. METHODS: Of 100 knees in 74 patients who underwent total knee arthroplasty without patellar resurfacing, 64 knees in 49 patients were available for follow-up (mean, 13.6 years). Clinical evaluations included the presence of anterior knee pain at final follow-up, Knee Society Score, Knee Society Functional Score and Kujala score. Plain radiographic evaluations assessed patellar thinning and its relationship with clinical outcomes. We also compared outcomes between remission and non-remission groups based on Disease Activity Score in 28 joints using C-reactive protein at final follow-up. RESULTS: The incidence of anterior knee pain was 9.3%. At follow-up, Knee Society Scores and Functional Scores had improved significantly (p < 0.05). Although patellar thinning progressed, it did not appear to affect clinical outcomes or incidence of anterior knee pain. Disease activity did not differ significantly between groups or by presence of anterior knee pain. CONCLUSIONS: Long-term outcomes of total knee arthroplasty without patellar resurfacing in rheumatoid arthritis were favourable, indicating that this approach is acceptable.

OBJECTIVES: Patients with lumbar spinal stenosis (LSS) exhibit significantly different scoring patterns on the visual analogue scale (VAS) chart for low back pain (LP), buttock and lower limb pain (PL), and buttock and lower limb numbness (NL). This study investigated the usefulness of these preoperative scoring patterns on the VAS chart in predicting surgical outcomes in older adults undergoing LSS surgery. METHODS: Time-course data from patients aged ≥65 years who underwent LSS surgery at two institutions were retrospectively assessed. All participants completed the Zurich Claudication Questionnaire and the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, which included the VAS chart, before surgery and at 6 months and 1 year postoperatively. RESULTS: In total, 334 participants were evaluated. Patients with equal preoperative scores across all three scales showed the highest average postoperative reduction in the three VAS scores. By contrast, those with the highest preoperative VAS scores for LP or NL had the lowest reductions. Based on the multivariable analysis, the highest preoperative VAS scores for LP (relative risk: 2.1) and NL (relative risk: 2.1) were significantly associated with poor surgical improvement in older adults with LSS. CONCLUSIONS: This study demonstrated the potential clinical utility of the preoperative VAS chart in predicting surgical improvement in older patients with LSS. Patients with equal preoperative VAS scores for LP, PL, and NL were more likely to have favorable surgical outcomes, while those with the highest preoperative scores for LP or NL were at higher risk for poor outcomes.