Partial femoral head replacement: a new innovative hip-preserving approach for treating osteonecrosis of the femoral head and its finite element analysis.

Purpose: Controversy remains regarding the optimal treatment for stage III Osteonecrosis of the femoral head (ONFH). This study presents, for the first time, the precise treatment of stage III ONFH using the "substitute the beam for a pillar" technique and performs a comparative finite element analysis with other hip-preserving procedures. Methods: A formalin-preserved femur of male cadavers was selected to obtain the CT scan data of femur. The proximal femur model was reconstructed and assembled using Mimics 20.0, Geomagic, and UG-NX 12.0 software with four different implant types: simple core decompression, fibula implantation, porous tantalum rod implantation, and partial replacement prosthesis. The finite element simulations were conducted to simulate the normal walking gait, and the stress distribution and displacement data of the femur and the implant model were obtained. Results: The peak von Mises stress of the femoral head and proximal femur in the partial replacement of the femoral head (PRFH) group were 22.8 MPa and 37.4 MPa, respectively, which were 3.1%-38.6% and 12.8%-37.4% lower than those of the other three surgical methods. Conclusion: The PRFH group exhibits better mechanical performance, reducing stress and displacement in the ONFH area, thus maintaining femoral head stability. Among the four hip-preserving approaches, from a biomechanical perspective, PRFH offers a new option for treating ONFH.

Severe medial osteoarthritis predicts patient dissatisfaction after proximal fibular osteotomy: a mid- to long-term follow-up study.

PURPOSE: This study aimed to investigate postoperative patient satisfaction at mid- to long-term follow-up after proximal fibular osteotomy and to identify risk factors for patient dissatisfaction. METHODS: This was a retrospective cross-sectional study that included 252 knees from 160 osteoarthritis (OA) patients who underwent proximal fibular osteotomy with a follow-up of four to eight years. Patients were categorized into a satisfied group (satisfaction score ≥ 20) or a dissatisfied group (satisfaction score < 20) based on the New Knee Society Score (New KSS). Patient demographics, preoperative pain visual analogue scale (VAS) score, preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Kellgren-Lawrence (K-L) grade, preoperative hip-knee-ankle (HKA) angle, and preoperative medial proximal tibial angle (MPTA) were compared between the two groups. Multiple logistic regression analysis was used to identify risk factors for patient dissatisfaction. RESULTS: Of the 203 knees, 130 (64.0%) were satisfied with their results. Multiple logistic regression analysis demonstrated that severe medial OA (K-L grade = IV) was an independent risk factor for patient dissatisfaction after proximal fibular osteotomy (OR 8.334, 95% CI 3.815-18.206, P < 0.001). CONCLUSION: Our study confirmed that proximal fibular osteotomy was a simple and effective treatment for medial OA patients, and majority of our patients obtained a higher satisfaction rate within mid- to long-term follow-up after surgery. Severe medial OA, however, was an independent risk factor for dissatisfaction.

Finite element analysis of basicervical femoral neck fracture treated with proximal femoral bionic nail.

BACKGROUND: Dynamic hip screws (DHS) and proximal femoral nail anti-rotation (PFNA) were recommended for basicervical femoral neck fracture (BFNF), however, with high rate of postoperative femoral neck shortening. The proximal femoral bionic nail (PFBN) was designed to decrease the postoperative complications associated with DHS and PFNA. The aim of this study is to compare the biomechanical characters of DHS, PFNA, and PFBN for fixation of BFNF. METHODS: Using finite element analysis, we created a three-dimensional model of the BFNF for this investigation. The PFBN group, the PFNA group and the DHS + DS group were our three test groups. For each fracture group, the von Mises stress and displacements of the femur and internal fixation components were measured under 2100 N axial loads. RESULTS: The PFBN group demonstrated the lowest stress on the implants, significantly lower than the PFNA and DHS + DS groups. In terms of stress on the implants, the PFBN group exhibited the best performance, with the lowest stress concentration at 112.0 MPa, followed by the PFNA group at 124.8 MPa and the DHS + DS group at 149.8 MPa. The PFBA group demonstrated the smallest displacement at the fracture interface, measuring 0.21 mm, coupled with a fracture interface pressure of 17.41 MPa, signifying excellent stability. CONCLUSIONS: Compared with DHS and PFNA, PFBN has advantages in stress distribution and biological stability. We believe the concept of triangle fixation will be helpful to reduce femoral neck shortening associated with DHS and PFNA and thus improve the prognosis of BFNF.

Role of Wnt signaling pathway in joint development and cartilage degeneration.

Osteoarthritis (OA) is a prevalent musculoskeletal disease that affects approximately 500 million people worldwide. Unfortunately, there is currently no effective treatment available to stop or delay the degenerative progression of joint disease. Wnt signaling pathways play fundamental roles in the regulation of growth, development, and homeostasis of articular cartilage. This review aims to summarize the role of Wnt pathways in joint development during embryonic stages and in cartilage maintenance throughout adult life. Specifically, we focus on aberrant mechanical loading and inflammation as major players in OA progression. Excessive mechanical load activates Wnt pathway in chondrocytes, resulting in chondrocyte apoptosis, matrix destruction and other osteoarthritis-related changes. Additionally, we discuss emerging Wnt-related modulators and present an overview of emerging treatments of OA targeting Wnt signaling. Ultimately, this review provides valuable insights towards discovering new drugs or gene therapies targeting Wnt signaling pathway for diagnosing and treating osteoarthritis and other degenerative joint diseases.

Efficacy and radiographic analysis of oblique lumbar interbody fusion for degenerative lumbar spondylolisthesis.

BACKGROUND: To compare the clinical efficacy and radiographic analysis of oblique lumbar interbody fusion (OLIF) and traditional posterior lumbar interbody fusion (PLIF) in treating degenerative lumbar spondylolisthesis (DLS). METHODS: Grade I DLS patients admitted to the Third Hospital of Hebei Medical University were retrospectively reviewed. In sum, 78 patients that underwent OLIF (n = 31) and PLIF (n = 47) treatment of DLS were recruited. Clinical data including clinical and radiological evaluations were collected pre-operatively and at each follow-up. Japanese Orthopaedic Association (JOA) scores, Oswestry Disability Index (ODI), lumbar lordosis (LL), disc height (DH), and fusion rates were compared between the OLIF and PLIF groups. RESULTS: The operation time for both groups was 131.3 ± 14.6 min in the OLIF group and 156.9 ± 37.4 min in the PLIF group (P < 0.001). The intraoperative blood loss was 163.6 ± 63.9 ml in the OLIF group and 496.8 ± 122.6 ml in the PLIF group (P < 0.001). The length of the surgical incision was 4.63 ± 0.57 cm in the OLIF group and 11.83 ± 1.37 cm in the PLIF group (P < 0.001). The number of intraoperative and post-operative complications for both groups was 10 in the OLIF group and 20 in the PLIF group. Significant clinical improvement (P < 0.05) was observed in JOA scores and ODI when comparing pre-operative evaluation and final follow-up. After statistical analysis, there was no significant difference in the preoperative JOA scores between the two groups. There was no significant difference when comparing pre-operative LL and DH for either group. Post-operative reexamination was improved as compared to pre-operative exams. And the improvement of DH was better in the OLIF group as compared to the PLIF group. CONCLUSIONS: For DLS patients, both OLIF and PLIF can achieve good results. Furthermore, OLIF displays marked advantages including smaller surgical incisions, shorter anesthesia times, decreased intraoperative blood loss, and post-operative pain better relieved.

A piezoelectric micro generator worked at low frequency and high acceleration based on PZT and phosphor bronze bonding.

Recently, piezoelectric energy harvesters (PEHs) have been paid a lot of attention by many researchers to convert mechanical energy into electrical and low level vibration. Currently, most of PEHs worked under high frequency and low level vibration. In this paper, we propose a micro cantilever generator based on the bonding of bulk PZT wafer and phosphor bronze, which is fabricated by MEMS technology, such as mechanical chemical thinning and etching. The experimental results show that the open-circuit output voltage, output power and power density of this fabricated prototype are 35 V, 321 µW and 8664 µW cm-3 at the resonant frequency of 100.8 Hz, respectively, when it matches an optimal loading resistance of 140 kΩ under the excitation of 3.0 g acceleration. The fabricated micro generator can obtain the open-circuit stable output voltage of 61.2 V when the vibration acceleration arrives at 7.0 g. Meanwhile, when this device is pasted on the vibrating vacuum pump, the output voltage is about 11 V. It demonstrates that this novel proposed device can scavenge high vibration level energy at low frequency for powering the inertial sensors in internet of things application.