Fracture risk assessment of vascularized medial femoral condylar bone graft: A finite element analysis.

BACKGROUND: Vascularized medial femoral condyle (MFC) bone graft is useful for pseudarthrosis and osteonecrosis, but has the risk of fracture as a complication. This study aimed to create multiple three-dimensional (3D) finite element (FE) femur models to biomechanically evaluate the fracture risk in the donor site of a vascularized MFC bone graft. METHODS: Computer tomography scans of the femurs of nine patients (four males and five females) with no left femur disease were enrolled in the study. A 3D FE model of the left femur was generated based on the CT images taken from the patients. The descending genicular artery (DGA), the main nutrient vessel in vascularized MFC bone grafts, divides into the proximal transversal branch (TB) and the distal longitudinal branch (LB) before entering the periosteum. Thirty-six different bone defect models with different sizes and locations of the harvested bone were created. RESULTS: The highest stress was observed in the proximal medial and metaphyseal portions under axial and external rotation, respectively. In the bone defect model, the stress was most elevated in the extracted region's anterior or posterior superior part. Stress increased depending on proximal location and harvested bone size. CONCLUSION: Increasing the size of the bone graft proximally raises the stress at the site of bone extraction. For bone grafting to non-load-bearing areas, bone grafting distally using LB can reduce fracture risk. If TB necessitates a larger proximal bone extraction, it is advisable to avoid postoperative rotational loads.

Change in hip laxity after anterior capsular suture in total hip arthroplasty using direct anterior approach.

It is clinically unclear whether anterior capsular suture improves hip laxity in total hip arthroplasty using direct anterior approach (DAA-THA). This study aimed to clarify the impact of anterior capsular suture for hip laxity in DAA-THA. In this study, 121 hips of 112 patients who underwent DAA-THA were prospectively enrolled. Mean age was 64.7 ± 10.1 years, and the subjects consisted of 35 hips in 32 men and 86 hips in 80 women. To evaluate hip laxity after implantation, axial head transfer distance (HTD) when the hip was pulled axially at 15 kg was compared before and after anterior capsular suture at the hip intermediate and 10° extension positions. HTD in the intermediate and 10° extension positions averaged 5.9 ± 4.6 mm and 6.3 ± 4.6 mm before the suture, and 2.6 ± 2.7 mm and 2.9 ± 3.1 mm after the suture, respectively. HTD after the suture significantly decreased in both hip positions (p < 0.0001). The amount of change by the suture was greater in cases with greater pre-suturing HTD. In DAA-THA, the anterior capsular suture significantly improved hip laxity against axial traction force, it may contribute to improvement of postoperative hip stability, especially in cases with greater laxity before the suture.

Negative correlation between central sensitization and forgotten joint score-12 after total hip arthroplasty.

BACKGROUND: Central sensitization is a condition in which even mild stimuli cause pain due to increased neuronal reactivity in the dorsal horn of the spinal cord. It is one of factors of chronic pain in patients with osteoarthritis. However, it is unknown whether central sensitization relates to clinical outcomes after total hip arthroplasty (THA). This study aimed to clarify whether preoperative central sensitization relates to the forgotten joint score-12 (FJS) after THA. Moreover, the secondary outcome was to identify which items in the FJS were most related by central sensitization. METHODS: This retrospective analysis included 263 hips (263 patients; 51 males and 212 females) that underwent primary THA in our institute and were available for evaluation one year postoperatively. The average patient age was 64.8 ± 11.9 years. The Central Sensitization Inventory (CSI) part A, which is a patient-reported outcome, was used to measure preoperative central sensitization. The correlation between preoperative CSI and postoperative FJS and the association between postoperative FJS and preoperative CSI severity were determined. Moreover, difference in each FJS item was evaluated by CSI severity. RESULTS: Twenty-six patients (9.9%) had central sensitization preoperatively. Preoperative CSI scores and postoperative FJS were negatively correlated (r = - 0.331, p < 0.0001). The postoperative FJS was significantly lower in patients with moderate or higher preoperative CSI severity than that in patients with subclinical or mild preoperative CSI severity (p < 0.05). FJS items with movement of daily life were significantly worse in the moderate or higher CSI severity compared with subclinical group (p < 0.05 or p < 0.01). CONCLUSION: Central sensitization prior to THA negatively related to postoperative FJS. In particular, the relationship of central sensitization was found to be significant in FJS items with movement, which would lead to lower patient satisfaction after THA. To get better postoperative outcomes in patients with preoperative central sensitization, improving central sensitization would be important.

Medial Soft Tissue-Preserving Technique Impact on Sagittal Stability in Bi-cruciate Stabilized Total Knee Arthroplasty.

Background: Sagittal stability in total knee arthroplasty is achieved through complex processes enabled by prosthetic design and intraoperative soft tissue balancing. This study investigated the effects of preserving medial soft tissue on sagittal stability in bicruciate stabilized total knee arthroplasty (BCS TKA). Method: This retrospective study included 110 patients who underwent primary BCS TKA. The patients were divided into two groups: 44 TKAs were performed releasing medial soft tissue (CON group), and 66 TKAs were performed preserving medial soft tissue (MP group). We assessed joint laxity using tensor device and anteroposterior translation immediately after surgery using the arthrometer at 30° knee flexion. Propensity score matching (PSM) was performed according to preoperative demographic and intraoperative medial joint laxity, and further comparisons between the two groups were performed. Result: After PSM analysis, medial joint laxity in the mid-flexion range tended to be smaller in the MP group than in the CONT group, with a significant difference at 60 degrees (CON group: - 0.2 ± 0.9 mm, MP group: 0.8 ± 1.3 mm, P < 0.05). Anteroposterior translation was significantly different between the two cohorts (CON group: 11.6 ± 2.5 mm, MP group: 8.0 ± 3.1 mm, P < 0.001). Conclusion: This study demonstrated the effects of preserving medial soft tissue on postoperative sagittal stability in BCS TKA. We concluded that this surgical procedure enhances postoperative sagittal stability in the mid-flexion range in BCS TKA.

Forgotten joint score is worse when the affected leg perceived longer than shorter after total hip arthroplasty.

BACKGROUND: One of the causes of patient dissatisfaction after total hip arthroplasty (THA) is leg length discrepancy (LLD). Even when radiographic LLD (R-LLD) is within 5 mm, some people perceive the affected side to be longer, while others perceive it is shorter. The purpose of this study was to investigate the relationship between perceived LLD (P-LLD), R-LLD, and Forgotten Joint Score (FJS-12) after THA. METHODS: A retrospective study of 164 patients with unilateral hip disease was conducted. Based on P-LLD after THA, they were classified into three categories: perceived short (PS 21 patients), no LLD (PN 121 patients), and perceived long (PL 22 patients). On the other hand, based on R-LLD after THA, they were divided into < - 5 mm (RS 36 patients), - 5 mm ≤ x < 5 mm (RN 99 patients), and 5 mm ≥ (RL 29 patients), respectively. The proportion of P-LLD in the RN group was also evaluated. In each group, the relationship between P-LLD, R-LLD and FJS-12 was investigated. RESULTS: After THA, the PL group had significantly worse FJS-12 (PS: 68.3 ± 26.2, PN: 75.0 ± 20.9, PL: 47.3 ± 25.2, P < .0001). In the R-LLD evaluation, there was no difference in FJS-12 among the three groups (RS: 73.7 ± 21.1, RN: 70.0 ± 24.5, RL: 67.7 ± 25.4, P < .53). The RN group perceived leg length to be longer (RN-PL) in 12.1% of cases, and the RN-PL groups had significantly worse FJS-12 (RN-PS: 65.4 ± 24.8, RN-PN: 73.8 ± 23.1, RN-PL: 41.8 ± 27.6, P < .0001). CONCLUSION: One year after THA, patients with longer P-LLD had worse FJS-12, even if the R-LLD was less than 5 mm.

Evaluation of the reproducibility of preoperative three-dimensional computed tomography planning for posterolateral approach total hip arthroplasty.

The anteversion of the stem is occasionally intentionally changed by the surgeon for patients with smaller femoral neck anteversion during total hip arthroplasty (THA). However, the reproducibility of preoperative planning with increasing anteversion has been rarely assessed. The present study investigated it using two types of stems. This retrospective study included patients who underwent primary posterolateral THA using taper-wedge (TS group; 73 hips) and anatomical (AS group; 70 hips) stems. Characteristics of sex and age were matched in the two groups by propensity score matching. In both groups, the relationship between the preoperative three-dimensional planning and postoperative stem position, and the relationship between postoperative stem position and femoral neck anteversion (FNA) were evaluated. In the TS group, there were no significant differences in average stem anteversion (SA) between preoperative planning and postoperative placement (36.1° ± 7.0° and 36.6° ± 11.1°, respectively: p = 0.651). The absolute error of SA was 8.1° ± 6.4°. In the AS group, the postoperative SA was significantly smaller than the preoperative planning SA (22.7° ± 11.6° and 30.0° ± 9.3°, respectively: p < 0.001). The absolute error of SA was 9.0° ± 5.8°. The postoperative SA was significantly larger than the FNA in the TS group (36.6° ± 11.1° and 26.3° ± 10.9°, respectively: p < 0.001). However, no significant differences between the two were observed in the AS group (23.7° ± 10.1° and 22.7° ± 11.6°, respectively: p = 0.253). The preoperative planning of intentional increasing anteversion did not show high reproducibility with taper-wedge and anatomical stems. The anatomical stem was placed according to the femoral medullary canal regardless of preoperative planning with increased SA.

Accuracy of cup placement using computed tomography-based navigation system in total hip arthroplasty through the direct anterior approach.

BACKGROUND: This study aimed to elucidate the accuracy of cup placement with the computed tomography (CT)-based navigation system (CTN) in the direct anterior approach (DAA)-total hip arthroplasty (THA) in the supine position compared with the mechanical cup alignment guide (MG) or the fluoroscopy (FS). METHODS: A total of 171 hips of 156 patients undergone primary THA were classified into the following three groups (the MG group: 63 hips, the FS group: 58 hips, the CTN group: 50 hips). Comparing the preoperative planning with postoperative CT measurement by three-dimensional templating software, the accuracy of cup placement was investigated in the three groups. RESULTS: There were significant differences in the mean absolute error of radiographic inclination (RI) between the MG group (4.4° ± 3.2°) and the CTN group (2.8° ± 2.5°) (p = 0.01). The mean absolute error of radiographic anteversion (RA) also showed significant differences between the CTN group (2.8° ± 1.9°) and the MG group (5.8° ± 4.7°) (p = 0.0001) or the FS group (4.8° ± 4.1°) (p = 0.02). Regarding the cup center position, the mean absolute error of vertical position from preoperative planning was the smallest in the CTN group (1.8 ± 1.4 mm) compared with those in other groups (MG: 3.3 ± 3.2 mm, p = 0.007, FS: 3.2 ± 3.0 mm, p = 0.017). CONCLUSION: The CTN guarantees accurate cup placement in the DAA-THA in the supine position compared with the MG and FS groups.

Comparing postoperative outcomes of two fully hydroxyapatite-coated collarless stems in total hip arthroplasty through propensity score matching analysis with 2 years follow-up.

A fully hydroxyapatite (HA)-coated stem such as Corail stem, that compacts the cancellous bone around the stem in total hip arthroplasty (THA), is reported to have good long-term results for more than 20 years. Although various fully HA-coated stems have being used recently, it is unclear whether there are differences in the postoperative outcomes. In this study, 224 patients (234 hips) with THA using either the Corail collarless stem or the Hydra stem were enrolled. And then we performed a retrospective comparison of the data at 2 years postoperatively using propensity score matching analysis. The postoperative modified Harris hip scores in 84 hips each group were 93.6 ± 8.2 points in the Corail group and 92.8 ± 10.1 points in the Hydra group, and there was no significant difference between the two groups. However, there was significantly less stem subsidence and rate of 3rd degree or greater stress shielding in the Corail group. Although these two stems were similar collarless fully HA-coated stems and clinical outcomes were favorable results in both groups at 2 years postoperatively, radiographic evaluations showed statistically significant differences between the two groups.

Effect of immersion in NaCl solution on the electrical conductivity and the reduction of the shear bond strength of resin-modified glass-ionomer-cements after current application.

Advancements in dental cements have considerably improved their bond strengths. However, high bond strength often makes the removal of restorations difficult. Thus, smart dental cements that show controllable bond strength are required. A conventional resin-modified glass-ionomer-cement demonstrated a significant reduction in the bond strength after current application. However, for this system, the ions in the cement are released into the oral cavity, resulting in a reduction of the electrical conductivity and in losses of the expected on-demand debonding property. Herein, the effects of immersion in 0.9 and 15% NaCl solutions on the electrical conductivity and debonding properties were investigated. The cement immersed in 0.9% NaCl solution from 1 to 28 days maintained similar bond strength reductions after current application, whereas that in 15% NaCl solution initially showed no bond strength reduction after 1 day but exhibited an increase in the bond strength reduction after immersion for 28 days.

Low frequency of local findings in periprosthetic hip infection caused by low-virulent bacteria compared to periprosthetic knee infection.

Periprosthetic joint infection (PJI) is suspected when local findings such as pain, swelling, hyperthermia, and sinus tract are present. However, the frequency of these findings and the difference between hip and knee are unclear. This study compared the positive rates of local findings in periprosthetic hip infection (PHI) with periprosthetic knee infection (PKI), and aimed to identify potential risk factors associated with the frequency. One hundred one PJI (46 hips and 55 knees) fulfilled the 2018 Musculoskeletal infection society criteria were analysed retrospectively to assess the positive rates of each local finding. Patients were categorized into two groups based on the presence or absence of each local finding, and the influence of two potential risk factors [body mass index (BMI) and C-reactive protein (CRP)] was investigated. Causative bacterial species were divided into high and low-virulent groups, and then culture negative cases were included in low-virulent group. PHI had significantly lower rates of pain, swelling and hyperthermia compared to PKI. Overall, up to one-third of PHI had pain as only symptom. High BMI and low-virulent bacteria were associated with lower frequency of swelling and hyperthermia in PHI. CRP had no impact on positive rates of local findings. PHI was oligosymptomatic in a significant percentage of cases. This is particularly important in obese patients and infection by low-virulent bacteria.

Evaluation of femoral anteversion, hip rotation, and lateral patellar tilt after total hip arthroplasty using a changeable neck system.

In patients with secondary osteoarthritis due to acetabular dysplasia, femoral anteversion has many variations. A changeable neck system is one useful option to adjust the femoral anteversion. Retroverted necks can effectively adjust anatomical anteversion (AA), femoral rotational angle (FRA), and functional anteversion (FA); however, effectiveness of anteverted necks for these adjustments has not been investigated. Moreover, although the lateral patellar tilt after total hip arthroplasty (THA) has been reported to externally rotate, the influence on lateral patellar tilt using a changeable neck system remains unknown. To clarify the effectiveness of anteverted necks in THA, 96 consecutive patients (111 hips) who underwent THA using anatomical short stem with a changeable neck system were retrospectively investigated using pre- and post-operative computed tomography. Patients were divided into the straight (ST) group using straight and 4-mm-high-offset neck (N = 34) and the anteverted (AV) group using 15°-anteverted and 15°-anteverted/3-mm-high-offset neck (N = 34) after age, body mass index, and surgical approach were matched using propensity scores. AA did not change in the ST group, while it increased by 14.0° in the AV group. FRA decreased after surgery in both groups. FA decreased after surgery in the ST group, while it did not change in the AV group. Lateral patella tilt did not significantly change in both groups between pre- and post-operative position. In conclusion, with a changeable neck system, straight and anteverted necks can adjust AA to achieve pre-operative planning while not influencing lateral patellar tilt.

Effects of water immersion on shear bond strength reduction after current application of resin-modified glass-ionomer-cements with and without an ionic liquid.

The enhancement in the bonding strength of advanced dental cements has enabled long-lasting dental restorations. However, the high bonding strength can cause difficulty in removing these restorations. Therefore, "smart" dental cements with simultaneous strong bonding and easy on-demand debonding ability are required. A resin-modified glass-ionomer-cement (RMGIC) with an ionic liquid (IL) has demonstrated significant reduction in the bonding strength with current application (CA). This research investigates the effect of immersion in distilled water on the electric conductivity and bonding strength of RMGIC with and without an IL and CA. The RMGIC without the IL exhibited significant electric conductivity after immersion, and a significant decrease in bonding strength with CA. In comparison, the electric conductivity after immersion and the decrease in bonding strength with CA were greater for RMGIC with the IL. Thus, the feasibility of smart dental cements capable of electrically debonding-on-demand is indicated.

Comparison of bacterial culture results of preoperative synovial fluid and intraoperative specimens in patients with joint infection.

OBJECTIVES: The details of relationship between bacterial culture results of preoperative and intraoperative specimens in same patients with native joint septic arthritis (NJSA) and periprosthetic joint infection (PJI) are unknown. This study aims to reveal the difference of culture results of preoperative synovial fluid and intraoperative specimens and evaluate the risk factors for detecting different species intraoperatively from preoperative synovial fluid. METHODS: This study included 55 joints diagnosed with 16 NJSA and 39 PJI. Bacterial culture positive rates and identified bacterial species were compared between preoperative synovial fluid and intraoperative tissue/synovial fluid. We also examined the presence or absence of sinus tracts and antimicrobial agents as risk factors in patients with different bacterial species in intraoperative specimens from preoperative synovial fluid. RESULTS: The culture positive rates were not significantly different between preoperative synovial fluid and intraoperative specimens. Different bacterium were detected in 10.9% joints by intraoperative tissue and 14.6% joints by intraoperative synovial fluid. The positive rate of sinus tract was significantly higher in patients with different bacterial species (62.5%) than without different bacterial species (12.8%, p < 0.01). Conversely, antimicrobial agent was not significantly difference. CONCLUSION: This study demonstrated that different bacterium from preoperative culture results were detected in 10-15% joints by intraoperative specimens in NJSA and PJI. The sinus tract was a risk factor for identifying different bacterial species in the intraoperative specimens. Therefore, in cases of sinus tract, it is necessary to examine multiple specimens of both intraoperative tissue and synovial fluid for increasing the detection rate.

Synovial fluid presepsin as a novel biomarker for the rapid differential diagnosis of native joint septic arthritis from crystal arthritis.

OBJECTIVE: To investigate whether presepsin can be used as a novel biomarker to differentiate between native joint septic arthritis (NJSA) and crystal arthritis (CA). METHODS: This study included 75 patients diagnosed with either NJSA (n = 21) or CA (n = 54). Presepsin in synovial fluid and blood, C-reactive protein, and procalcitonin were measured and compared between the NJSA and CA groups. Receiver operating characteristic (ROC) curve analyses were performed to differentiate between the two groups. RESULTS: Synovial fluid and blood presepsin were significantly higher in the NJSA group than in the CA group (p < 0.0001 and p < 0.01, respectively). The area under the ROC curve for synovial fluid presepsin in the NJSA group compared with the CA group was 0.93 (sensitivity 85.7%, specificity 85.2%, positive predictive value 69.2%, negative predictive value 93.9%, positive likelihood ratio 5.79, negative likelihood ratio 0.17). Among the tests, synovial fluid presepsin was the most accurate. CONCLUSIONS: Measurement of synovial fluid presepsin is reliable for the early diagnosis of NJSA, and synovial fluid presepsin could be used as a novel biomarker for differentiating between NJSA and CA.

Investigation of the effect of intraoperative mediolateral stability on postoperative sagittal stability after bi-cruciate stabilized total knee arthroplasty.

PURPOSE: This study investigated the effect of mediolateral stability on sagittal stability in bi-cruciate stabilized total knee arthroplasty. METHOD: This study included 59 patients. We intraoperatively assessed the component gap with a joint distraction force of 60 N for each compartment. Immediately after surgery, sagittal stability was assessed using an arthrometer. RESULT: The intraoperative medial joint laxity at 30° of flexion was significantly correlated with postoperative anteroposterior translation (r = 0.276, p < 0.05). CONCLUSION: This study demonstrated the effect of intraoperative mediolateral stability effect on postoperative sagittal stability. Improving medial stability may enhance postoperative sagittal stability.