Journal of Orthopaedic Science最新文献

Background: Real-time ultrasound monitoring of muscle architecture changes during dynamic contractions is gaining traction as a practical tool for neuromuscular functional assessment.

Purpose: This study aimed to assess the muscle thickness (MT) and deformation velocity of rectus femoris (RF) for predicting muscle strength capacity, evaluating their predictive validity and clinical feasibility.

Methods: Twenty-three elderly individuals with knee osteoarthritis (KOA) were examined. The thickness of the muscle at rest (MT_rest) and at maximal voluntary isometric contraction (MT_contraction), the velocity from rest state to maximum contraction (Velocity_activation) and the velocity from maximal contraction to rest state (Velocity_relaxation) were obtained by M-mode ultrasound. Maximum flexor and extensor strength were measured using an isokinetic dynamometer, the gold-standard assessment tool.

Results: MT_rest and MT_contraction were significantly correlated with extension strength, also showed correlations with flexion strength. Velocity_activation correlated significantly with both strength (extension: r = 0.742; flexion: r = 0.707). Velocity_activation, but not MT, remained a statistically significant predictor of both extension and flexion strength in multivariate regression models (extension: adjusted R² = 0.381; flexion: adjusted R² = 0.314).

Conclusions: The deformation of RF, as measured by M-mode ultrasound, provides a visualization method for assessing extension and flexion strength. Velocity_activation showed a significant correlation with both extension and flexion strength. Furthermore, it improved the prediction of thigh muscle strength beyond muscle thickness (MT) alone. Assessing the deformation of RF by M-mode ultrasound may be valuable for detecting alterations in muscle strength and function throughout the disease process in individuals with knee osteoarthritis (KOA).

Background: Lumbar degenerative disease involves age-related structural and functional changes in the spine, often leading to impaired motor function and decreased quality of life. Although oxidative stress may influence muscle function, its relationship with dynamic postural control remains unclear.

Methods: This exploratory cross-sectional study enrolled 46 Japanese patients (mean age 60.5 ± 16.3 years) undergoing posterior lumbar spine surgery for lumbar degenerative disease, including lumbar spinal stenosis and lumbar disc herniation. Trunk flexion and extension during sit-to-stand movements were assessed using three-dimensional motion analysis. Systemic oxidative stress was evaluated using urinary 8-hydroxy-2'-deoxyguanosine in 34 patients, and local oxidative stress was assessed by dihydroethidium staining of the lumbar multifidus muscle in 32 patients. Associations among dynamic trunk parameters, oxidative stress markers, and Oswestry Disability Index scores were examined using linear regression analyses.

Results: Dynamic trunk extension was significantly reduced during the sit-to-stand task compared with the static baseline posture (p < 0.001, r = 0.794). In multivariable analyses, higher low back pain intensity and reduced walking capacity were independently associated with worse Oswestry Disability Index scores, whereas trunk extension was not a primary determinant in the main model but showed a significant association in sensitivity analyses. Higher urinary 8-hydroxy-2'-deoxyguanosine levels and greater dihydroethidium intensity were associated with reduced trunk extension.

Conclusions: These findings suggest a potential link between oxidative stress and impaired dynamic trunk extension. In patients with lumbar degenerative disease, disability during daily activities is primarily associated with pain and walking capacity. Dynamic trunk extension may represent an important postural strategy rather than a direct determinant of disability. Oxidative stress was associated with reduced trunk extension in exploratory sub-analyses, warranting further investigation in longitudinal or interventional studies.

Background: Degenerative medial meniscal tears (DMMTs) pose challenges in surgical management, with varying repair outcomes. This study aimed to identify preoperative factors associated with early clinical failure after isolated arthroscopic meniscal repair of DMMTs.

Methods: This study retrospectively reviewed data from patients (mean age, 49.0 ± 9.1 years) who underwent isolated all-inside medial meniscal repair at two institutions (2018-2025). The evaluated potential predictors included patient characteristics (demographics, symptom duration), radiographic alignment measures (Kellgren-Lawrence grade, percentage of the mechanical axis [%MA] as a continuous variable, and %MA<30 % as a categorical cutoff, medial proximal tibial angle), magnetic resonance imaging findings (joint effusion, defined by an effusion-synovitis score of ≥1 based on the magnetic resonance imaging Osteoarthritis Knee Score; cartilage damage; bone marrow lesions), and meniscal tear features (location, morphology). Significant variables identified through univariate analysis were included in the multivariate logistic regression.

Results: Forty-three knees were analyzed (23 successes [54 %], 20 failures [46 %]). The Kellgren-Lawrence grade based on preoperative radiographs was distributed as follows: 0/1/2 = 9/26/8. On preoperative MRI, cartilage damage was observed for 14 knees (32.6 %). Failures had a higher prevalence of preoperative effusion (85.0 % vs 30.4 %, p = 0.001) and lower mean %MA (36.8 ± 12.3 vs 44.7 ± 12.0, p = 0.036). %MA<30 % was more frequent among failures (40.0 % vs 8.7 %, p = 0.028). Multivariate analysis identified preoperative effusion (odds ratio [OR]: 17.7, 95 % confidence interval [CI]: 3.6-178.0, p < 0.001) and %MA<30 % (OR: 12.4, 95 % CI: 1.8-166.6, p = 0.008) as independent predictors of failure.

Conclusions: Preoperative joint effusion and varus malalignment (%MA<30 %) were significant predictors of early clinical failure 6 months after isolated arthroscopic meniscal repair for DMMTs.

Background: Mild cervical ossification of the posterior longitudinal ligament (OPLL) is often asymptomatic or minimally symptomatic; however, its impact on physical function remains unclear. Locomotive syndrome (LS), a condition involving a decline in mobility due to musculoskeletal disorders, may help predict early functional impairments beyond neurological deficits. This study aimed to assess the severity of LS in patients with mild OPLL using the locomotive syndrome risk test battery.

Methods: This cross-sectional study included 37 patients with mild OPLL (Japanese Orthopaedic Association score ≧16 points) and 73 propensity score-matched controls with no major comorbidities. All participants underwent three LS assessments: the stand-up test, two-step test, and 25-question Geriatric Locomotive Function Scale (GLFS-25). LS stages were defined according to the Japanese Orthopaedic Association criteria. Group comparisons were performed using Student's t-test and the Chi-Square test.

Results: The OPLL group demonstrated significantly lower two-step and stand-up test scores (P < 0.05) and higher GLFS-25 scores (P = 0.0102) than controls. A significantly higher proportion of the OPLL group was classified as having LS stage 2 (32.4 % vs. 15.1 %, P = 0.0017), indicating more advanced locomotor dysfunction.

Conclusion: Patients with mild cervical OPLL and preserved neurological function exhibited greater LS severity and subjective disabilities. The GLFS-25 effectively captured functional and psychosocial burden not reflected in traditional neurological scores, suggesting the need for early screening and mindful diagnostic communication.

Background: Open-wedge high tibial osteotomy (OWHTO) is an established procedure for medial compartment knee osteoarthritis. However, postoperative progression of patellofemoral osteoarthritis (PFOA) and its clinical relevance remain uncertain. The objective of this study was to determine whether radiographic PFOA progression after OWHTO is associated with postoperative patient-reported outcomes and to identify factors associated with progression.

Methods: We retrospectively reviewed 116 knees in 104 patients who underwent OWHTO with ≥4 years of follow-up. PFOA progression could be evaluated in 114 knees (two lacked preoperative Merchant views) using a morphology-based, two-view radiographic assessment integrating Merchant and true lateral views and focusing on interval changes in osteophytes and joint-space narrowing. Knees were classified as progression (Group P) or non-progression (Group N). Clinical outcomes were assessed using the Japanese Knee injury and Osteoarthritis Outcome Score (J-KOOS). Factors associated with progression were examined using univariate and multivariable logistic regression.

Results: Radiographic PFOA progression was observed in 63/114 knees (55 %). At final follow-up, postoperative J-KOOS was significantly lower in Group P for Symptoms, Pain, Activities of Daily Living, and Quality of Life, whereas Sports/Rec did not differ significantly between groups. In multivariable logistic regression, greater preoperative knee extension loss and a higher PF Kellgren-Lawrence (KL) grade were independently associated with PFOA progression.

Conclusions: Radiographic PFOA progression after OWHTO, as classified using a morphology-based two-view radiographic assessment, was associated with inferior postoperative patient-reported outcomes despite comparable improvement from baseline. Greater preoperative knee extension loss and higher PF KL grade were associated with an increased likelihood of progression and may inform preoperative counseling and surgical planning.

Background: Distal radius fractures of OTA/AO types 23B and 23C have a high incidence, and inadequate treatment can lead to complications such as traumatic arthritis, joint pain, and limited wrist function. This study aimed to utilize three-dimensional computed tomography (3D-CT) reconstruction technology and fracture line mapping frequency charts to intuitively and clearly describe the morphological characteristics of distal radius fractures (OTA/AO types 23B and 23C), thereby deepening the understanding of such fractures and providing reference information for this clinical condition.

Methods: Patients with OTA/AO types 23B and 23C distal radial fractures who met the inclusion criteria at our hospital were retrospectively analyzed. A three-dimensional model of the fracture was established using CT scans. The articular surface fracture model and the articular depression area were superimposed on the standard model, and the fracture line map, frequency map, and articular depression map were generated.

Results: This study included 212 patients, comprising 67 males and 145 females. There were 104 left-hand fractures and 108 right-hand fractures. The mean age of the enrolled patients was 59.71 ± 13.21 years, ranging from 18 to 88. In terms of injury mechanisms, 172 (81.13 %) resulted from falls, 17 (8.02 %) from falls from height, 12 (5.66 %) from accidents, and 11 (5.19 %) from other factors. The main fracture lines and areas of high fracture frequency were located in the lunate fossa, scaphoid fossa, and its dorsal region. In the fracture frequency map, the high-frequency fracture area exhibited a clear "+" shape pattern, particularly in the dorsal and central regions of the scaphoid fossa, where the fracture involvement frequencies reached 76 % and 67 %, respectively. Conversely, the four corners of the nine segments of the articular surface of the distal radius were less frequently involved, with frequencies in the radial volar and ulnar volar regions at 18 % and 26 %, respectively. Compared to the palmar side, the dorsal side showed more depressions. The depressed area was the most frequently involved part, notably located in the center and dorsal area of the lunate fossa and scaphoid fossa.

Conclusions: The intra-articular fracture line map, frequency map, and articular depression map of the distal radius were created to reveal the morphological distribution characteristics of fracture lines of types 23B and 23C in the OA classification, allowing for the intuitive identification of prone fracture sites, which may aid clinical diagnosis and surgical guidance.

Background: Spontaneous posterior interosseous nerve (PIN) palsy is a rare condition with controversial clinical features. Although this palsy is conventionally treated conservatively, interfascicular neurolysis to release hourglass-like fascicular constrictions has also been recommended. This study aimed to clarify the clinical characteristics and treatment guidelines for this palsy.

Methods: Fifty-eight limbs with spontaneous PIN palsy receiving conservative treatment or interfascicular neurolysis. The presence of pain as a premonitory symptom and the degree of muscle weakness were investigated. Patients were followed periodically from 3 months after palsy onset to either recovery or ≥36 months afterwards. Limbs recovering to manual muscle testing (MMT) grade 4 or better for both the extensor pollicis longus and extensor digitorum were rated as Good recovery, with all others judged as Poor.

Results: Good recovery was achieved in 31 of 34 limbs treated conservatively and 19 of 24 of limbs by interfascicular neurolysis. Younger age at onset was the factor significantly associated with achieving Good recovery in 58 limbs treated by conservatively or interfascicular neurolysis. In the 24 limbs treated by interfascicular neurolysis, early timing of surgery was the factor significantly associated with attaining Good recovery. All 27 limbs with conservative treatment displaying ≥1 grade of MMT improvement within 6 months after onset achieved Good recovery. In the 23 limbs with Poor recovery at 6 months by conservative treatment, Good recovery was attained in 4 of 7 limbs by continuing conservative treatment and in 12 of 16 limbs by subsequent interfascicular neurolysis. Although the latter treatment tended to produce better results, no significant difference was detected.

Conclusions: Diverse clinical characteristics of spontaneous PIN palsy are useful for diagnosis. Conservative treatment is advisable within 6 months after onset of palsy. If no improvement is observed, interfascicular neurolysis without delay is a reasonable option.

Background: Augmented reality (AR)-based navigation has gained popularity in total hip arthroplasty (THA) due to its imageless, user-friendly approach. However, factors influencing the accuracy of cup placement remain unclear. This study aimed to evaluate the accuracy of AR-guided cup placement and identify risk factors associated with placement error of 5°or more.

Methods: This retrospective, single-center study included 128 patients (132 hips) who underwent THA with AR-based navigation in the lateral decubitus position. Postoperative cup positioning was assessed via X-rays and computed tomography scans. Absolute errors in intraoperative and postoperative measurements, along with the achievement of the combined anteversion (CA) safe zone, were calculated. Patients were divided into two groups based on cup placement errors of ≥5°. The associations of patient demographics and spinopelvic parameters with cup anteversion and inclination malalignment were analyzed using logistic regression models with Firth's penalized likelihood.

Results: Mean absolute errors were 2.8° ± 2.2° for cup anteversion and 3.1° ± 2.8° for cup inclination, with 92 % of cases achieving the CA safe zone. Errors of ≥5° were found in 28 hips (21 %) for anteversion and 24 hips (18 %) for inclination. After adjusting for confounders, Firth's penalized multivariable logistic regression analysis identified significant associations between malaligned anteversion and body mass index (BMI) (odds ratio [OR], 1.16; 95 % confidence interval [CI], 1.03-1.32; P = 0.01) and pelvic obliquity (PO) (OR, 1.47; 95 % CI, 1.11-1.98; P = 0.01). Malaligned inclination was also significantly associated with PO (OR, 1.96; 95 % CI, 1.47-2.78; P < 0.001).

Conclusions: AR-based navigation achieved cup placement accuracy comparable to previous reports. However, PO was associated with greater differences between intraoperative navigation and postoperative radiographic measurements for both anteversion and inclination, while higher BMI was associated with anteversion differences. Careful pelvic landmark registration is advised in such patients.

Background: Valgus-impacted and nondisplaced femoral neck fractures in older adults are commonly treated with cannulated screw fixation. However, the optimal timing for initiating postoperative weight-bearing remains controversial. This study aimed to compare immediate weight-bearing (IWB) as tolerated versus delayed weight-bearing (DWB) to determine whether IWB could improve patient outcomes without increasing the risk of surgical complications.

Methods: A total of 136 patients aged 65 years or older with valgus-impacted or nondisplaced femoral neck fractures treated using three cannulated screws were retrospectively analyzed. The patients were divided into two groups: the IWB group, which began weight-bearing on the first postoperative day and the DWB group, which started weight-bearing six weeks after surgery. All patients were followed for a minimum of 12 months. Outcome measures consisted of surgical complications, perioperative complications, postoperative length of hospital stay (LOS), and functional recovery evaluated with the Modified Barthel Index (MBI) and the Harris Hip Score (HHS).

Results: No significant differences were observed in surgical complications between the two groups. The IWB group had a lower overall perioperative complication rate (6.2 % vs. 18.1 %, p = 0.035) and shorter postoperative LOS (4.9 ± 1.6 vs. 5.6 ± 1.9 days, p = 0.028) than the DWB group. The MBI and HHS were higher in the IWB group at 1 and 3 months postoperatively, while the differences were not statistically significant at 6 and 12 months.

Conclusion: For older patients with valgus-impacted or nondisplaced femoral neck fractures, immediate weight-bearing as tolerated following cannulated screw fixation may have a positive effect on reducing perioperative complications, shortening postoperative LOS, and promoting early functional recovery, without increasing surgical complications.