Stress distribution patterns during the gait cycle in patients with anterior femoral notching following total knee replacement.

BACKGROUND: Anterior femoral notching (AFN) is a severe complication of total knee replacement (TKR), which in a percentage of patients may lead to fractures after surgery. The purpose of this study was to investigate the stress distribution in patients with AFN and the safety depth of AFN during the gait cycle. METHODS: We performed a finite element (FE) analysis to analyse the mechanics around the femur during the gait cycle in patients with AFN. An adult volunteer was selected as the basis of the model. The TKR models were established in the 3D reconstruction software to simulate the AFN model during the TKR process, and the 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm AFN models were established, after which the prosthesis was assembled. Three key points of the gait cycle (0°, 22°, and 48°) were selected for the analysis. RESULTS: The stress on each osteotomy surface was stable in the 0° phase. In the 22° phase, the maximum equivalent stress at 3 mm was observed. In the 48° phase, with the increase in notch depth, each osteotomy surface showed an overall increasing trend, the stress range was more extended, and the stress was more concentrated. Moreover, the maximum equivalent force value (158.3 MPa) exceeded the yield strength (115.1 MPa) of the femur when the depth of the notch was ≥ 3 mm. CONCLUSIONS: During the gait cycle, if there is an anterior femoral cortical notch ≥ 3 mm, the stress will be significantly increased, especially at 22° and 48°. The maximum equivalent stress exceeded the femoral yield strength and may increase the risk of periprosthetic fractures.

Cognitive behavioral therapy cannot relieve postoperative pain and improve joint function after total knee arthroplasty in patients aged 70 years and older.

PURPOSE: A randomized controlled trial was conducted to investigate whether cognitive behavioral therapy (CBT) can improve postoperative pain, knee function, and negative emotion in patients aged 70 years and older who underwent total knee arthroplasty (TKA). METHODS: This study used randomized, parallel group, controlled trial to divide the included 90 patients into CBT group and usual care group. The primary outcome measure of the study was the Visual Analogue Scale (VAS) at activity. The secondary outcome measures included the Self-Rating Anxiety Scale (SAS), Self-Rating Depression Scale (SDS), Knee Range of Motion (ROM), Oxford Knee Score (OKS), Hospital for Special Surgery Knee Rating Scale (HSS), analgesics dose, and postoperative complications. RESULTS: 83 patients who met the criteria were randomized into CBT group and usual care group. In the SAS, score of the CBT group decreased by 4.3 points at 7th day and 8.2 at 14th day after surgery with respect to preoperative SAS score, the usual care group increased by 1.5 at 7th day and decreased 1.1 at 14th day, and tended to be similar at 3rd month after surgery. There were no significant differences at 7th and 14th day in SDS, however, score of the CBT group was 5.8 and the usual care group was 1.9 at 3rd month after surgery. No statistically significant differences in VAS at activity, ROM, OKS, HSS, analgesics frequency, and postoperative complications between two groups. CONCLUSIONS: CBT was superior to usual care group in relieving anxiety at 7th day and 14th day, and depression at 3rd month, however, CBT cannot relieve postoperative pain and improve joint function after TKA in patients aged 70 years and older.

Porous tantalum implant for treatment of early-stage osteonecrosis of the femoral head: a minimum 5-year follow-up study.

BACKGROUND: To evaluate the survival rate of porous tantalum rod implantation in the treatment of osteonecrosis of the femoral head (ONFH), evaluate its clinical effect and imaging results. METHODS: From January 2008 to December 2013, porous tantalum rod implantation for ONFH was performed in two institutions. Statistical analysis of operation data, including operation time, blood loss and blood transfusion were recorded. RESULTS: 52 hips received complete follow-up, the average follow-up time was 85.7 months (60-132 months). 24 hips turned to THA at the end of follow-up (46.2%), the average time was 44.3 ± 32.8 months, and the average Harris hip score before THA was 57.1 ± 7.6. Cox proportional-hazards model revealed that Association Research Circulation Osseous (ARCO) stage (P = 0.017), bone marrow edema (P = 0.006) and age > 40 years (P = 0.043) were independent risk factors for conversion to THA. CONCLUSION: ARCO stage, age and bone marrow edema were risk factors for the failure of porous tantalum rod implantation to convert to THA.

Design, synthesis and evaluation of novel ferulic acid derivatives as multi-target-directed ligands for the treatment of Alzheimer's disease.

A series of new ferulic acid derivatives were designed, synthesized and evaluated as multi-target inhibitors against Alzheimer's disease. In vitro studies indicated that most compounds showed significant potency to inhibit self-induced ß-amyloid (Aß) aggregation and acetylcholinesterase (AChE), and had good antioxidant activity. Specifically, compound 4g exhibited the potent ability to inhibit cholinesterase (ChE) (IC50, 19.7 nM for hAChE and 0.66 µM for hBuChE) and the good Aß aggregation inhibition (49.2% at 20 µM), and it was also a good antioxidant (1.26 trolox equivalents). Kinetic and molecular modeling studies showed that compound 4g was a mixed-type inhibitor, which could interact simultaneously with the catalytic anionic site (CAS) and the peripheral anionic site (PAS) of AChE. Moreover, compound 4g could remarkably increase PC12 cells viability in hydrogen peroxide-induced oxidative cell damage and Aß-induced cell damage. Finally, compound 4g had good ability to cross the BBB using the PAMPA-BBB assay. These results suggested that compound 4g was a promising multifunctional ChE inhibitor for the further investigation.

Early Stage Versus Late Stage Periarticular Injection during Unicompartmental Knee Arthroplasty for Postoperative Pain Relief: A Randomized Controlled Trial.

Controlling postoperative pain after unicompartmental knee arthroplasty (UKA) is essential to improve patient satisfaction and promote early recovery. The purpose of this study was to investigate the difference in clinical efficacy between early and late stage periarticular injection during UKA for postoperative pain relief. Eighty-four patients meeting the inclusion and exclusion criteria were randomly divided into the early stage periarticular injection group and late stage periarticular injection group by using a random number tables method. The difference between the two groups was that the early stage periarticular injection group received superficial injection before the joint incision, while the late stage periarticular injection group received superficial injection after implantation of the prosthesis. Deep injection and other perioperative conditions of the two groups were controlled identically. The primary outcome of the study was the recovery room immediate visual analog scale (VAS) at rest. The secondary outcomes were the postoperative VAS (at rest) at 3, 6, 9, 12, 18, 24, 48, 72, 96, and 120 hours, drug dosage of rescue analgesia, range of motion (ROM), and complications. The recovery room immediate VAS (at rest) in the early stage periarticular injection group was significantly lower than that of the late stage periarticular injection group (21 ± 24 vs. 32 ± 34 mm, p = 0.018), the average difference of the VAS reached the minimal clinically important difference. No statistically significant difference in postoperative drug dosage of rescue analgesia, ROM, and complications. Preemptive analgesia combined with the early stage periarticular injection can better alleviate postoperative pain than the late stage periarticular injection.

Radiotherapy for the prophylaxis of heterotopic ossification after total hip arthroplasty: A systematic review and meta-analysis of randomized controlled trails.

Heterotopic ossification (HO) refers to the formation of lamellar bone in soft tissues and is a significant complication after total hip arthroplasty (THA). Radiotherapy has been proven as an effective prophylaxis especially for those patients with high risk of HO after THA. However the dose, timing, and frequency of radiation have yet to be determined. To compare HO progressions with different radiotherapy strategies and explore an optimal radiation option. We systematically searched PubMed, Embase, and Cochrane Library for randomized controlled trails (through December 1, 2019; no language restrictions) collecting patients who accepted prophylaxis radiation for whom HO progression outcomes were reported. Of 87 identified studies, 10 randomized controlled trails including 1203 patients and 1268 hips were taken to this analysis. Compared with the low biologically effective radiation dose group (biologically effective dose [BED] < 20 Gy), the medium biologically effective radiation dose group (20 Gy ≤ BED ≤ 24 Gy) had statistically significant difference on the prophylaxis of HO (p = 0.003). But for overall incidence of HO, there was no statistically significant difference between low BED group and high BED group (BED > 24, p = 0.21). There was statistically significant reduction in the prophylaxis of HO progression with multiple fractions as opposed to single fraction radiotherapy (p = 0.04). Hips with preoperative radiation were no more likely to observe HO progression than those with postoperative radiotherapy (p = 0.43). Radiotherapy with medium dose (20 Gy ≤ BED ≤ 24 Gy) after THA is an effective dose for preventing HO. In the prophylaxis of HO, multiple fractions seem to be more effective than single fraction radiation. Preoperative radiotherapy could prevent HO progression with the same efficacy postoperative.