Journal of Orthopaedic Science最新文献

Background: Spinal instrumentation surgery has seen improvements in safety and invasiveness thanks to technological innovations such as navigation systems, robotics, and improved implants, and its indications have expanded. This, combined with an increase in patients from aging population, has led to a global rise in surgical cases, particularly in countries with aging societies. However, Japan previously lacked a nationwide registry, making it difficult to fully understand the epidemiological trends of these surgeries. To address this, the Japanese Society of Spinal Instrumentation (JSIS) developed the web-based, multi-institutional case registration database (JSIS-DB) in 2018.

Methods: This study analyzed 32,656 confirmed cases registered in the first- and second-generation JSIS-DB between 2018 and 2022. Patient background, implants used, and complications were statistically compared across age groups and surgical procedures. Statistical analysis included Chi-square tests, Wilcoxon rank-sum tests, and logistic regression analysis were used for intergroup comparisons.

Results: Regional disparities were observed with a notable concentration of registered cases in metropolitan areas. Patient age showed a bimodal distribution peaking in the teens and seventies. Two-thirds of procedures used posterior approaches. Minimally invasive techniques were significantly more frequent in elderly patients. Revision surgeries showed higher complication rates and more frequent cases without implant use. Systemic and psychiatric complications significantly increased with age. The proportion of patients aged 90 or older undergoing surgery showed a significant annual increase of 0.13 % (p = 0.014).

Conclusions: This study presents the first analysis of spinal instrumentation surgery in Japan using a nationwide registry. The results revealed that surgical procedures are being selected based on age and risk factors, ranging from children to the super-elderly. Moving forward, appropriate surgical selection and perioperative management in a super-aged society will become increasingly important. The JSIS-DB is expected to play a significant role as a foundation for future quality improvement and clinical research.

Background: To investigate the effectiveness of the Modified Kappa-line (mKappa-line) and Modified K-line (mK-line) as prognostic tools in managing ossification of the posterior longitudinal ligament (OPLL)-induced cervical myelopathy, especially in selective laminoplasty (LMP) cases.

Methods: This retrospective study analyzed 78 patients who underwent LMP for OPLL-induced cervical myelopathy between September 2012 and April 2017. Patients were categorized based on their mKappa-line and mK-line statuses. Radiographic measurements, Japanese Orthopaedic Association (JOA) scores, and Neck Disability Index (NDI) were comprehensively analyzed.

Results: Patients in the mKappa-line (-) group exhibited significantly higher OPLL thickness (6.4 ± 1.7 mm; P < 0.01) and canal occupying ratio (64.4 %; P < 0.01) compared to the mKappa-line (+) group. The mKappa-line (-) group also reported lower postoperative JOA scores at 6 months (11.2 ± 4.1 vs. 14.5 ± 2.5; P = 0.01) and at the final follow-up (11.3 ± 4.0 vs. 14.4 ± 2.5; P = 0.01). Multivariate analysis highlighted the interval (INT) of mKappa-line as the sole significant predictor of JOA recovery rate (P = 0.037). Receiver operating characteristic (ROC) curve analysis revealed an area under the curve (AUC) of 0.792 for the mKappa-line (P < 0.01) and 0.675 for the mK-line (P < 0.01), with a critical cut-off value of 1.88 mm for the mKappa-line (INT), below which an inferior outcome (JOA RR < 40 %) is associated.

Conclusions: The mKappa-line serves as a superior prognostic tool compared to the mK-line, providing enhanced guidance for surgical planning in selective LMP cases. Further research is warranted to confirm these findings and assess their clinical implications.

Purpose: This study aimed to evaluate the influence of psychological factors, demographics, and radiological parameters on functional outcomes following combined medial patellofemoral ligament reconstruction (MPFLr) and tibial tubercle transfer (TTT) for recurrent lateral patellar instability.

Methods: A cross-sectional study was conducted on 31 patients who underwent unilateral MPFLr with TTT between 2019 and 2023. Preoperative and postoperative evaluations included the Caton-Deschamps (CD) index, tibial tubercle-trochlear groove (TT-TG) distance, patellar tilt, and trochlear morphology (sulcus angle, trochlear groove angle, sagittal spur, and lateral trochlear inclination). Patient-reported outcomes were assessed with the Kujala score, KOOS subscales, and the SF-12 physical (PCS-12) and mental (MCS-12) scores, which represent health-related quality of life (QoL). Psychological assessments included the Tampa Scale of Kinesiophobia (TSK), Pain Catastrophizing Scale (Pcs), and Brief Resilience Scale (BRS). Potential predictors of functional outcomes were analyzed using a post-LASSO ordinary least squares (OLS).

Results: Significant postoperative reductions were observed in TT-TG distance (22.45 ± 2.69 mm to 10.58 ± 3.51 mm, p < 0.001), CD index (1.53 ± 0.40 to 1.07 ± 0.26, p < 0.001), and patellar tilt (36.52 ± 11.26° to 18.03 ± 8.38°, p < 0.001). Females demonstrated higher TT-TG index and trochlear groove angle, despite comparable postoperative corrections. Females also showed poorer functional outcomes on the Kujala scale (p = 0.010), KOOS symptoms (p = 0.008), and KOOS sport/recreation (p = 0.048). Psychological analyses revealed higher TSK scores in females (p = 0.039). Post-LASSO OLS showed kinesiophobia as a significant negative predictor of Kujala, KOOS sport/recreation, KOOS knee-related QoL, and total KOOS scores, whereas resilience positively predicted PCS-12. Sulcus angle independently predicted higher KOOS pain, symptoms, and ADL.

Conclusions: Combined MPFLr and TTT corrected malalignment, significantly decreasing TT-TG distance, tilt, and height. Female patients had poorer outcomes, but kinesiophobia emerged as the strongest negative factor, resilience supported health-related QoL, and sulcus angle independently predicted unfavorable KOOS subscales. Beyond surgical correction, treatment should integrate psychological factors-often neglected-into multidisciplinary rehabilitation, particularly for female patients.

Level of evidence: Level IV.

Background: Acetabular fractures are among the most complex orthopaedic injuries, requiring precise anatomical reduction and stable fixation. Infra-acetabular screw (IAS) enhances fixation strength by closing the periacetabular frame. This study aims to determine entry points and corridor parameters for IAS placement in the South Asian population, identify gender-specific differences, and evaluate its practical usability in managing acetabular fractures.

Methods: CT scans of 200 hemipelves (100 pelvises) were analysed using RadiAnt DICOM Viewer. Exclusion criteria included patients under 18 years of age, prior pelvic fractures, or bony pathologies. An all-intraosseous screw trajectory was defined. Parameters measured included entry point distances, corridor length, diameter, and angles in the axial and sagittal planes. Gender-specific differences were statistically analysed.

Results: Significant gender differences were noted in entry point distances (from the pubic symphysis, anterior wall, and medial wall), corridor length, and axial-plane angle. Females required more lateral angulation for screw placement. Only 13 percent of the hemipelves in our study had a corridor diameter ≥5 mm, which differs from studies conducted on Western populations. The mean minimum diameter was narrower compared to Western populations, indicating that a 3.5 mm screw is optimal for the South Asian population.

Conclusion: This study provides comprehensive dimensions for IAS placement, highlighting gender-specific planning requirements. These findings enhance preoperative planning and patient-specific treatment strategies for complex acetabular fractures.

Background: The efficacy of intradiscal condoliase injection for lumbar disc herniation (LDH) may vary depending on the affected disc level. This is especially relevant in upper lumbar herniations, where anatomical constraints can complicate surgical treatment. Although condoliase has emerged as a less invasive option, disc-level-specific outcomes remain underexplored.

Methods: This multicenter retrospective cohort study included 262 patients with LDH who underwent either intradiscal condoliase injection (CD group, n = 207) or microendoscopic discectomy (MED group, n = 55). Patients were categorized by herniation level: upper lumbar (L1/2, L2/3, L3/4) and lower lumbar (L4/5, L5/S1). The primary objective was to examine whether the effectiveness of condoliase differs by disc level. MED outcomes were included for reference. Primary outcomes included improvement in numerical rating scale (NRS) scores for leg and back pain at 1 year, responder rate (≥50 % improvement in leg pain), and reoperation rate. Intermediate-term (3-6 month) NRS data were also analyzed in a subset.

Results: Condoliase demonstrated consistent efficacy across disc levels, with particularly favorable outcomes at upper lumbar levels. At L1/2-L3/4, the CD group achieved a 100 % responder rate and the greatest mean improvement in leg pain (6.9 ± 2.4). At L3/4, outcomes in the CD group were superior to those in the MED group (100 % vs. 57.1 % responder rate). At L4/5, while condoliase was effective, reference data from the MED group showed greater leg pain relief (7.2 ± 2.5 vs. 5.0 ± 2.8) and a higher responder rate (100 % vs. 81.2 %). At L5/S1, both treatments produced similar results. Improvements in low back pain were modest and comparable across levels and groups. In the subset analysis, MED showed faster early symptom relief at L4/5, but condoliase provided steady improvement over time.

Conclusion: The effectiveness of condoliase injection therapy differs by disc level and appears particularly favorable at upper lumbar levels. Condoliase represents a safe, minimally invasive alternative for treating upper lumbar LDH. These findings support disc-level-based treatment selection when choosing between condoliase and surgical intervention.

Purpose: Ulnar shortening osteotomy (USO) is a standard treatment for ulnar impaction syndrome and triangular fibrocartilage complex (TFCC) injuries. However, complications such as delayed union, nonunion, and refracture after implant removal remain controversial issues. This study aimed to evaluate the clinical outcomes of modified step-cut USO using an osteotomy guide and a specialized ulnar shortening plate designed to maximize bone contact, enhance fixation stability, and reduce the invasiveness of the procedure.

Methods: A retrospective case series involving 23 consecutive patients (23 wrists) who underwent step-cut USO using a dedicated osteotomy guide and plate (Nagoya, Japan) between 2021 and 2024 was conducted. The indications for surgery included ulnar impaction syndrome (n = 14) and TFCC tears (n = 9). The outcomes assessed included wrist range of motion, grip strength, pain using Visual analogue Scale (VAS), Disabilities of the Arm, Shoulder, and Hand score (DASH), radiographic union, and complications.

Results: At a mean follow-up of 15.3 months, significant improvements were observed in the VAS and DASH scores, while the range of motion and grip strength were preserved. All patients achieved bone union, with a mean union time of 13 weeks and complete consolidation at 8 months. One patient with osteoporosis showed delayed union but achieved final healing. No cases of nonunion, implant-related complications, or fractures were observed. Mild plate irritation occurred in six cases but did not interfere with the patients' daily activities.

Conclusion: Step-cut USO using a dedicated ulnar shortening device is characterized by high bone union rates and minimal complications, providing a reliable low-profile fixation method and potentially reducing complications associated with conventional techniques.

Level of evidence: IV (Therapeutic case series).

Background: Weight-bearing long-leg radiographic image is used to evaluate alignment of the entire lower extremity, and the mechanical axis is the line connecting the femoral head center with the center of the ankle. However, the ankle varus/valgus angulation is compensated by subtalar joint; therefore, calcaneus inclusion is appropriate to evaluate lower leg alignment. The current digital imaging techniques reveal the calcaneus despite the bony overlap. The purpose of this study is to examine where the line from the center of the femoral head to the lowest point of the calcaneus passes through the ankle joint on the long-leg weight-bearing AP view.

Methods: This retrospective study used weight-bearing simulation computed tomography to examine the calcaneal outline location in the weight-bearing long-leg AP view of 46 healthy participants. We defined the plafond loading point on the long-leg AP view as the location where the line from the femoral head center to the lowest point of the calcaneal outline crosses the ankle joint. We measured and compared the plafond loading point in 46 normal feet and 84 feet with ankle osteoarthritis at each stage.

Results: In the long-leg AP view, the calcaneal outline was positioned at 69.9 % from the anterior edge of the calcaneus in the lateral image. The plafond loading point was located at 86.8 % from the medial side of the plafond in the normal group, 67.4 %, 48.3 %, 44.4 %, and 70.1 % in stages 2, 3a, 3b, and 4, respectively.

Conclusions: The true mechanical axis, drawn from the femoral head center to the lowest point of the calcaneus, passes laterally through the ankle in the normal group. As osteoarthritis progresses to stage 3b, it shifts medially, then slightly returns laterally in stage 4. Therefore, including the calcaneus is appropriate to evaluate the mechanical axis of the whole lower extremity.

Objectives: Assessment of distraction osteogenesis (D.O.) regenerates has traditionally relied on qualitative assessment on plain radiographs. The commonly employed methods are qualitative and are prone to inter-observer bias. Quantitative methods like the pixel density ratio have been described, but these have certain limitations. This study aimed to describe a novel technique to quantify regenerates from plain digital radiographs and compare it with the conventional Bone Mineral Density.

Methods: This was a prospective study. Eleven subjects underwent distraction osteogenesis; each patient was followed up monthly with digital radiographs and regenerate bone mineral density (BMD ratio) assessment by DEXA scan monthly for a minimum of 6 months. Quantitative analysis was performed by a novel technique using the ImageJ software, and the Area Fraction (AF) & Fractal Dimension (FD) of the regenerates were determined and compared with the BMD ratio.

Results: AF increased steadily and FD decreased steadily as the regenerate matured. A weak negative correlation was found between the BMD ratio and FD (AP view: r = -0.28, p = 0.1 and lateral view: r = -0.16, p = 0.36). A moderate correlation was found between BMD ratio and AF (AP view: r = 0.46, p = 0.005 and lateral view: r = 0.34, p = 0.004). There was a significant difference in AF and FD values in the initial and final regenerates.

Conclusion: Our novel quantitative image-based analysis technique using AF and FD has the potential to efficiently quantify and monitor distraction osteogenesis regenerates. However, these results must be validated in larger patient cohorts before this technique can be used in routine clinical practice.

Background: Chemonucleolysis with condoliase is a minimally invasive treatment for lumbar disc herniation (LDH). However, optimal patient selection criteria remain unclear. This study aimed to identify predictive factors for successful condoliase therapy in LDH, focusing on low back pain (LBP) and leg pain improvement.

Methods: This multi-institutional observational study included 238 patients who underwent intradiscal condoliase injection for LDH. Demographic and clinical data were collected, including pain intensity using the Numeric Rating Scale (NRS) for leg and back pain at baseline, 3-6 months, and 12 months. MRI assessments evaluated disc height, Pfirrmann grade, and herniation occupancy ratio. The primary outcome was defined as achieving the minimum clinically important difference (MCID) on the 0-10 NRS, defined as an improvement of ≥2 points at 3-6 months or 12 months, without additional surgery during follow-up. Multivariable logistic regression was used to identify predictors of MCID achievement.

Results: Condoliase was effective, with over 70 % of patients achieving MCID for leg pain and over 50 % for LBP. For LBP at 3-6 months, higher baseline back pain intensity (OR 3.09, 95 % CI 2.00-4.78), lower MRI slip (OR 0.59, 95 % CI 0.38-0.92), higher MRI occupancy rate (OR 1.74, 95 % CI 1.19-2.54), and L5/S1 injection level (OR 2.20, 95 % CI 1.06-4.54) predicted MCID achievement. At 12 months, higher baseline back pain intensity (OR 2.26, 95 % CI 1.49-3.44), higher MRI occupancy rate (OR 1.85, 95 % CI 1.24-2.79), shorter disease duration (OR 0.57, 95 % CI 0.38-0.86), and absence of X-ray posterior slip (presence: OR 0.18, 95 % CI 0.04-0.91) were associated with MCID achievement. For leg pain at 3-6 months, lower MRI slip (OR 0.60, 95 % CI 0.41-0.89) and higher baseline leg pain intensity (OR 1.72, 95 % CI 1.23-2.41) were associated with MCID achievement. For leg pain at 12 months, shorter disease duration (OR 0.61, 95 % CI 0.42-0.88), lower X-ray slip (OR 0.54, 95 % CI 0.30-0.97), higher baseline leg pain intensity (OR 1.94, 95 % CI 1.30-2.88), and lower Pfirrmann grade (OR 0.48, 95 % CI 0.23-0.99) were predictive of MCID achievement.

Conclusions: This study identified key factors associated with successful outcomes of condoliase in LDH. Baseline pain intensity, MRI findings (herniation occupancy rate, slip), injection level, and disease duration were significant predictors of treatment outcomes. These findings may aid clinicians in patient selection and improve treatment success.

Background: Adult spinal deformity (ASD) surgery involves instrumentation, which can lead to implant-related complications (IRCs) and unplanned returns to the operating room (UPROR). Older patients often have risk factors like osteoporosis and multiple comorbidities, but research on how age-related factors affect IRCs and UPROR across age groups is limited. The aim of this study was to evaluate the characteristics of UPROR due to IRCs between older and non-older patients following ASD surgery.

Methods: A retrospective analysis of patients (≥20 years) who underwent spinal fusion with instrumentation from 2010 to 2019 based on a multi-center database. Medical records were reviewed to identify ASD diagnoses and details of IRCs, including UPROR timing. UPROR timing was classified as early (<30 days), intermediate (30-90 days), and late (>90 days) postoperatively. Patients were stratified into older (≥65 years) and non-older (<65 years) groups to compare the characteristics of UPROR between the groups.

Results: IRCs occurred in 56 of 565 ASD cases (9.9 %) within 2 years postoperatively. UPROR was required in 38 patients (6.7 %), with implant breakage being the most frequent cause (23 cases), followed by screw malposition (14 cases). Screw-related complications predominated early, whereas implant breakage was most common in the late postoperative period. No significant differences in overall IRC or UPROR prevalence were observed between age groups. However, younger patients exhibited a higher rate of early UPROR (44.4 % vs. 20.0 % within 30 days).

Conclusions: These findings highlight the distinct characteristics of IRCs between older and non-older patients, particularly in terms of UPROR timing. Understanding temporal patterns of these complications can inform surgical strategies and enhance patient outcomes by reducing UPROR.