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Abstract Background Resecting the facet joint to relieve nerve pain can lead to spinal instability, deformity, and abnormal pressure on the anterior of the intravertebral disc. To mitigate these issues, surgeons often limit the amount of bone removed during facetectomy or stabilize the spine by fusion to maintain lumbar stability. This study aimed to assess how a M-PEEK rod system influenced the stability of the lumbar spine during graded facetectomy. Methods Facetectomy was performed on a validated L1-L5 finite element model which was then simulated both with and without the M-PEEK rod system. Results In extension, models implanted with M-PEEK in the interspinous space of L3/L4 experienced a 35.2% decrease in range of motion (ROM) at L3/L4, while others saw an 8.4–24.8% increase. For axial rotation, the ROM at L3/L4 increased by 2.2–5.4% in models with the M-Rod, and by 4.9–12.9% in models without the implant. In lateral flexion, the ROM at L3/L4 increased by 8.4–14.3% in models without a PEEK M-Rod (facetectomy only), with adjacent segments experiencing a 6.5% decrease in ROM in the implanted models. Overall, the difference in ROM between the intact and implanted models was minimal. Conclusions Facetectomy involving the removal of 50% or more of the facet joint significantly increases range of motion and maximum intradiscal pressure, potentially accelerating disc degeneration, as shown in our finite element study. Stabilizing the segment with an M-PEEK rod may limit excessive motion, providing stability and maintaining intradiscal pressure closer to that of an intact model.

Background/Purpose: Hip fractures are associated with physical dysfunction, and poor quality of life in the elderly. Post-acute care (PAC) would facilitate functional recovery in patients with hip fractures after surgeries. Taiwan has proposed a nationwide PAC program for hip fractures since 2017, but little has been known about its effectiveness. Therefore, this study aimed to evaluate the efficacy and cost-effectiveness of the PAC program for hip fracture patients in Taiwan. Methods: This was a prospective study. Patients aged ≥ 65 years with hip fractures after surgeries were recruited and divided into home-based, hospital-based, and control groups. Outcome measures included pain, physical function (sit-to-stand test, Barthel Index [BI], and Harris hip score [HHS]), and quality of life (EuroQol instrument [EQ-5D]). Direct medical and non-medical costs were recorded. Cost-effectiveness ratio (CER) was calculated as the amount of New Taiwanese Dollars (NTDs) paid per BI and EQ-5D unit improvement. Results: Forty-one patients participated in this study, with 17, 12, and 12 in the home-based, hospital-based, and control groups, respectively. The home-based group showed significant improvements in BI and HHS compared to the controls (p = 0.018 and p = 0.029, respectively). The hospital-based group demonstrated significant improvement in EQ-5D compared to the controls (p = 0.015). The home-based PAC program demonstrated the best CER for BI (NTD 554) and EQ-5D (NTD 41948). Conclusion: Both PAC programs would significantly improve the physical function and quality of life in patients with hip fractures. However, the home-based PAC provided the best CER for BI and EQ-5D.

Introduction Evidence suggests that patients with fragility fractures would benefit from post-acute care (PAC); however, they have been subjected to varying PAC programs. This study aimed to compare the effectiveness of home-based PAC (HPAC) to inpatient PAC (IPAC) programs for patients with fragility fractures in Taiwan. Materials and methods This is a retrospective study that reviewed the medical records of patients who received HPAC or IPAC within three weeks after hip, knee, or spine fragility fractures in the Taipei City Hospital from September 1, 2017, to August 31, 2018. Results The mean age (78.9 ± 10.8 years) showed significant difference between the HPAC (age = 80.6 ± 11.1, n = 83) and the IPAC (age = 78.2 ± 10.6, n = 185) groups ( P = .049). After PAC, both HPAC and IPAC groups showed improvement on Barthel index, numerical pain rating scale, and Harris hip score (all P < .001). Patients in the HPAC group displayed greater improvement than the IPAC group on Barthel Index for activities of daily living (ADLs) by 5.8 (95% confidence interval, 3.0 to 8.5). The IPAC group had a significant longer length of PAC than the HPAC group (12.4 ± 3.0 vs. 11.1 ± 2.7, P < .001). Conclusion Both PAC programs could significantly improve functional performance and reduce pain in patients with fragility fractures. Patients treated in the HPAC group had better ADLs, and less length of PAC.

Hallux valgus (HV) is a foot deformity most commonly found in female and elderly patients. Its symptoms include foot pain, impaired gait patterns, poor balance, and falls in older adults. Recently, various HV orthoses have been introduced in the market; however, they have many shortcomings, such as high costs, unclear therapeutic effects, and effects on push-off of the foot during walking. The present study employs 3D printing technology to develop an HV orthosis and uses motion analysis to investigate the effects of wearing it. This study recruited 12 individuals with HV, who were asked to first perform a static HV measurement without orthosis, followed by a dynamic HV measurement using a Vicon motion analysis system in three trials. The results indicated that wearing the 3D-printed orthosis significantly corrected the HV angle by approximately 11° during static standing and by approximately 9° during dynamic walking. However, no significant difference was observed during use of the orthosis in terms of the ground reaction force. The obtained results demonstrate that the 3D-printed HV orthosis is an effective device for correcting the HV angle during static standing and dynamic walking, especially during the push-off phase of gait.

Background: Pedicle-screw-based posterior dynamic stabilization devices are designed to alleviate the rate of accelerated degeneration of the vertebral level adjacent to the level of spinal fusion. A new pedicle- screw-based posterior dynamic stabilization device- the Awesome Dynamic Rod System was designed with curve cuts on the rods to provide flexibility. The current study was conducted to evaluate the biomechanical properties of this new device. Methods: Finite element models were developed for the intact spine (INT), the Awesome Dynamic Rod Implanted at L4-L5 (AWE), a traditional rigid rod system implanted at L4-L5 along with an interbody cage (FUS), and the Awesome Dynamic Rod System implanted at L4-L5 along with an interbody cage as an adjunct to fusion procedures and extension of dynamic fixation to L3-L4 (AWEFUS). The models were subjected to axial loads and pure moments and evaluated by a hybrid method on range of motion (ROM)s, disc stresses, pedicle screws stresses, and facet joint contact forces. Results: FUS sustained the lowest L4-L5 ROM decrement in flexion and torsion. AWE demonstrated the lowest adjacent level ROM increment in all moments except for extension at L3-L4, and AWEFUS showed the greatest ROM increment at L2-L3. AWE demonstrated lowest adjacent segment disc stress in flexion, lateral bending and torsion at L3-L4. AWEFUS showed the highest disc stress increment in flexion, extension, and lateral bending, and the lowest disc stress decrement in torsion at L2-L3. AWE sustained greater adjacent facet joint contact forces than did FUS in extension and lateral bending at L3-L4, and AWEFUS demonstrated the greatest contact forces concentrating at L2-L3. Conclusion: The results demonstrate that the Awesome Dynamic Rod System preserved more bridged segment motion than did the traditional rigid rod fixation system except in extension. However, the Awesome Dynamic Rod System bore a greater facet joint contact force in extension. The Awesome Dynamic Rod System did protect the adjacent level of fusion segments, but led to much greater ROM, disc stresses, and facet joint contact forces increasing at the adjacent level of instrumented segments. [ABSTRACT FROM AUTHOR]

Background: The Dynesys system provides stability for destabilized spines while preserving segmental motion. However, clinical studies have demonstrated that the Dynesys system does not prevent adjacent segment disease. Moreover, biomechanical studies have revealed that the stiffness of the Dynesys system is comparable to rigid fixation. Our previous studies showed that adjusting the cord pretension of the Dynesys system alleviates stress on the adjacent level during flexion. We also demonstrated that altering the stiffness of Dynesys system spacers can alleviate stress on the adjacent level during extension of the intact spine. In the present study, we hypothesized that omitting the cord preload and changing the stiffness of the Dynesys system spacers would abate stress shielding on adjacent spinal segments. Methods: Finite element models were developed for - intact spine (INT), facetectomy and laminectomy at L3-4 (DEC), intact spine with Dynesys system (IntDyWL), decompressed spine with Dynesys system (DecDyWL), decompressed spine with Dynesys system without cord preload (DecDyNL), and decompressed spine with Dynesys system assembled using spacers that were 0.8 times the standard diameter without cord pretension (DecDyNL0.8). These models were subjected to hybrid control for flexion, extension, axial rotation; and lateral bending. Results: The greatest decreases in range of motion (ROM) at the L3-4 level occurred for axial rotation and lateral bending in the IntDyWL model and for flexion and extension in the DecDyWL model. The greatest decreases in disc stress occurred for extension and lateral bending in the IntDyWL model and for flexion in the DecDyWL model. The greatest decreases in facet contact force occurred for extension and lateral bending in the DecDyNL model and for axial rotation in the DecDyWL model. The greatest increases in ROMs at L2-3 level occurred for flexion, axial rotation and lateral bending in IntDyWL model and for extension in the DecDyNL model. The greatest increases in disc stress occurred for flexion, axial rotation and lateral bending in the IntDyWL model and for extension in the DecDyNL model. The greatest increases in facet contact force occurred for extension and lateral bending in the DecDyNL model and for axial rotation in the IntDyWL model. Conclusions: The results reveals that removing the Dynesys system cord pretension attenuates the ROMs, disc stress, and facet joint contact forces at adjacent levels during flexion and axial rotation. Removing cord pretension together with softening spacers abates stress shielding for adjacent segment during four different moments, and it provides enough security while not jeopardizes the stability of spine during axial rotation. [ABSTRACT FROM AUTHOR]

The role of the vertebral body's rotation and the loading conditions of the brace has not been clearly identified in adolescent idiopathic scoliosis. This study aimed to implement a finite element (FE) model of C-type scoliotic spines to investigate the influence of different loading conditions on variations of Cobb's angle and the vertebral rotation. The scoliotic FE model was constructed from C7 to L5, and its geometry was the right thoracic type (37.4°) with an apex over T7. Three loading conditions included a medial-lateral (ML) and anteroposterior (AP) force with a magnitudes of 100-0, 80-20 and 60-40 N. Those forces were respectively applied over the 6th, 7th and 8th ribs. According to an analysis of Cobb's angle, the 100 N ML force that was applied over the 8th rib could achieve the best correction effect. Furthermore, the ML force was dominant in alterations of Cobb's angle, whereas the AP force was dominant in alterations of the axial vertebral rotation. Additionally, the level below the apex was the most appropriate level to apply the force to correct C-type scoliosis. [ABSTRACT FROM AUTHOR]

Abstract  Plantar heel pain is a commonly encountered orthopedic problem and is most often caused by plantar fasciitis. In recent years, different shapes of insole have been used to treat plantar fasciitis. However, little research has been focused on the junction stress between the plantar fascia and the calcaneus when wearing different shapes of insole. Therefore, this study aimed to employ a finite element (FE) method to investigate the relationship between different shapes of insole and the junction stress, and accordingly design an optimal insole to lower fascia stress. A detailed 3D foot FE model was created using ANSYS 9.0 software. The FE model calculation was compared to the Pedar device measurements to validate the FE model. After the FE model validation, this study conducted parametric analysis of six different insoles and used optimization analysis to determine the optimal insole which minimized the junction stress between plantar fascia and calcaneus. This FE analysis found that the plantar fascia stress and peak pressure when using the optimal insole were lower by 14% and 38.9%, respectively, than those when using the flat insole. In addition, the stress variation in plantar fascia was associated with the different shapes of insole. [ABSTRACT FROM AUTHOR]