Effects of the Coronavirus disease 2019 pandemic on mortality in patients with lung cancer: A multiple mediation analysis in Japan.

COVID-19 pandemic has had a substantial effect on healthcare systems worldwide, including the care of patients with lung cancer. The impact of healthcare disruptions and behavioral changes on lung cancer mortality is unclear. Patients newly diagnosed with lung cancer during the pandemic period 2020-2021 were compared with those diagnosed in the pre-pandemic 2018-2019. The primary outcome was all-cause mortality within 1 year. Cox proportional hazards regression analyses were conducted to estimate the changes in mortality between pandemic and pre-pandemic. Multiple mediation analyses were performed to determine the factors that accounted for the changes in mortality. In total, 5785 patients with lung cancer were included in this study. The overall mortality rate was significantly higher during the pandemic compared with the pre-pandemic (crude hazard ratio [HR]: 1.19, 95% confidence interval [CI]: 1.05, 1.29). Mediation analyses showed that not receiving tumor-directed treatment, diagnosis at an older age, and decreased diagnosis through cancer screening significantly accounted for 17.5% (95%CI: 4.2, 30.7), 13.9% (95%CI: 0.8, 27.0), and 12.4% (95%CI: 3.0, 21.8) of the increased mortality, respectively. This study revealed a significant increase in mortality risk in patients with lung cancer who have not received tumor-directed treatment or cancer screening, despite potential selection bias for follow-up status. Efforts should be focused on ensuring timely access to healthcare services, optimizing treatment delivery, and addressing the unique challenges faced by patients with lung cancer during the pandemic to mitigate the impact of the pandemic on lung cancer outcomes and provide clinical care to vulnerable populations.

Impact of home visiting nurses on home death proportion in Japan: A nationwide longitudinal ecological study.

OBJECTIVE: Home visiting nurses contribute to end-of-life home care in an aging society. However, few previous studies reported patient outcomes based on nursing practices. This study aimed to examine the correlation between the number of them and the change in home death proportion. METHODS: We divided the number of home visiting nurses into four categories: absent, shortage, medium, and abundant. This study adopted the interaction term between the nurse categories and year as the major exposure variable, and home death proportion per municipality as the objective variable. We estimated the average marginal effects (AME) as the change in home death proportion from 2015 to 2020. RESULTS: The total number of home visiting nurses was 36,483 in 2015 and 65,868 in 2020. The coefficients of the interaction term were statistically significant in medium and abundant municipalities (Medium: 1.26 (95% CI: 0.49-2.04), Abundant: 2.15 (95% CI: 0.76-3.55)). Increased home death proportion were estimated as AME: 1.56% (95% CI: 0.99-2.13), 1.35% (95% CI: 0.85-1.84), 2.82% (95% CI: 2.30-3.35), and 3.71% (95% CI: 2.44-4.99) in the absent, shortage, medium, and abundant areas, respectively. CONCLUSIONS: To increase the proportion of home deaths, municipalities require a certain number of home visiting nurses.

Safety and Early Return to Sports for Early ACL Reconstruction in Young Athletes: A Retrospective Study.

Background and Objectives: Although previous reports have shown that early anterior cruciate ligament (ACL) reconstruction is associated with an increased risk of stiffness, recommendations for delayed surgery are based on outdated literature. The advent of arthroscopic surgery and accelerated rehabilitation protocols warrants a reexamination of the optimal surgical timing. The purpose of this study was to investigate complications during early ACL reconstruction after injury in young athletes. Materials and Methods: A total of 87 patients (27 males and 60 females) were included in this study. Patients who underwent anatomic ACL reconstruction using hamstring autografts were evaluated. Patients under 25 years of age with a Tegner activity score greater than 6 were included and classified into three groups according to the time from injury to surgical treatment: one week from injury to surgery (early group), three to six weeks from injury to surgery (normal group), and three to six months from injury to surgery (delayed group). We evaluated the rates of various complications such as graft rupture, contralateral injury, the need for manipulation for loss of ROM, infection, and fracture around the knee up to 2 years postoperatively. In addition, we investigated postoperative muscle strength, Lysholm score, Tegner activity score, and period of the return to sport from injury. Results: Patients in the delayed group were younger than those in the other groups (p = 0.009). Patients in the early group had a lower range of motion than those in the other groups preoperationly. However, the 1-month postoperative range of motion was comparable between groups. Patients in the early group had greater postoperative Tegner activity scores than those in the other groups. The period of return to sport from injury in the delayed group was longer than in the other groups. There were no statistically significant differences in the postoperative complication rate, muscle strength, or Lysholm score. Conclusions: ACL reconstruction performed 1 week from injury to surgery in young athletic patients indicated the rate of complications were not significantly different among the groups. Early ACL reconstruction with no postoperative complications may be related to early return to sports and a high level of sports.

Concise Synthesis of Cyctetryptomycin A and B Enabled by Zr-Catalyzed Dimerization.

A concise synthetic strategy utilizing a Zr catalyst for the construction of cyctetryptomycin A and B is reported. Cyctetryptomycin A and B are recently isolated, complex tetrameric natural products for which total synthesis has not been previously reported. This study presents a practical approach for the construction of two consecutive quaternary carbon centers with a Zr catalyst. Furthermore, the first total synthesis of cyctetryptomycin A and B was achieved by this Zr-catalyzed radical coupling. The radical dimerization reaction mediated by the Zr catalyst required 1,2-bis(diphenylphosphino)ethane (dppe) as an indispensable additive. Through both experimental and theoretical investigations into the mechanism of this Zr-catalyzed reaction, the specific role of dppe was elucidated. In addition, the synthetic approach was extended to enable the practical synthesis of other dimeric natural products, including tetratryptomycin A, dibrevianamide F, and ditryptophenaline. Finally, the synthetic mechanism of cyctetryptomycin A and B, through the oxidative macrocyclization of tetratryptomycin A by CttpC, was newly elucidated by both experimental and docking simulations.

Theoretical Investigation of Chemoselectivity between C-H Insertion and Amide Insertion in Intramolecular Rhodium-Carbene Reactions.

C-H insertion and amide insertion reactions using metal-carbene species provide a powerful synthetic method for direct functionalization of kinetically inert or thermodynamically stable chemical bonds. Our group previously developed an amide insertion reaction using a rhodium-dimer complex, constructing an array of nitrogen-bridged heterocycles. Another research group reported C-H insertion reactions using structurally related substrates and rhodium catalysts. Detailed mechanistic studies were not provided, however, and therefore, the origin of the chemoselectivity was ambiguous. Here we describe our theoretical investigation of the chemoselectivity between the amide insertion reaction and C-H functionalization. An energy gap of the identified transition states in the reaction coordinates could support the reported experimental results and the observed chemoselectivity. Moreover, frontier molecular orbital analysis revealed that functionalities adjacent to the metal-carbene species could affect orbital populations and their energy levels, resulting in the construction of a completely distinctive ring system.

Increased care-need in older long-term care insurance users after the 2018 Japan Floods: a retrospective cohort study based on the Japanese long-term care insurance claims.

BACKGROUND: Level of care-need (LOC) is an indicator of elderly person's disability level and is officially used to determine the care services provided in Japan's long-term care insurance (LTCI) system. The 2018 Japan Floods, which struck western Japan in July 2018, were the country's second largest water disaster. This study determined the extent to which the disaster affected the LOC of victims and compared it with that of non-victims. METHODS: This is a retrospective cohort study, based on the Japanese long-term care insurance claims from two months before (May 2018) to five months after the disaster (December 2018) in Hiroshima, Okayama, and Ehime prefectures, which were the most severely damaged areas in the country. A code indicating victim status, certified by a residential municipality, was used to distinguish between victims and non-victims. Those aged 64 years or younger, those who had the most severe LOC before the disaster, and those whose LOC increased even before the disaster were excluded. The primary endpoint was the augmentation of pre-disaster LOC after the disaster, which was evaluated using the survival time analysis. Age, gender, and type of care service were used as covariates. RESULTS: Of the total 193,723 participants, 1,407 (0.7%) were certified disaster victims. Five months after the disaster, 135 (9.6%) of victims and 14,817 (7.7%) of non-victims experienced the rise of LOC. The victim group was significantly more likely to experience an augmentation of LOC than the non-victim group (adjusted hazard ratio 1.24; 95% confidence interval 1.06-1.45). CONCLUSIONS: Older people who were affected by the disaster needed more care than before and the degree of care-need increase was substantially more than non-victims. The result suggests that natural disasters generate more demand for care services among the older people, and incur more resources and cost for society than before.

Improving visualization of the articular cartilage of the knee with magnetic resonance imaging under axial traction: a comparative study of different traction weights.

OBJECTIVE: Lesions of the articular cartilage of the knee, especially early grades, are not always accurately detected by magnetic resonance imaging (MRI) because of contact between the articular cartilage surfaces of the femur and the tibia. This study aimed to assess the effects of axial leg traction during knee MRI examination on joint space widening and articular cartilage visualization and evaluate the ideal weight for traction. METHODS: MRI was performed on ten healthy volunteers using a 3-T MRI unit with a 3D dual-echo steady-state gradient-recalled echo sequence. Conventional MRI was performed first, followed by traction MRI. The traction weight increased in the order of 5 kg, 10 kg, and 15 kg. Joint space widths were measured, and articular cartilage visualization was assessed at the medial and lateral tibiofemoral joints. Volunteers were asked to evaluate pain and discomfort using a visual analog scale during each procedure with axial traction to assess the safety of traction MRI. RESULTS: The medial tibiofemoral joint space width significantly increased, and the visualization of the articular cartilage significantly improved by applying traction. The joint space width and the articular cartilage visualization showed no significant differences among traction weights of 5 kg, 10 kg, and 15 kg. Pain and discomfort during traction MRI examination were lowest with a traction weight of 5 kg. CONCLUSION: Traction MRI examination may be useful in evaluating articular cartilage lesions at the medial tibiofemoral joint. A traction weight of 5 kg may be sufficient with minimum pain and discomfort.

Calcium phosphate-hybridized tendon grafts reduce femoral bone tunnel enlargement in anatomic single-bundle ACL reconstruction.

PURPOSE: This study aimed to clarify the effect of calcium phosphate (CaP)-hybridized tendon grafting versus unhybridized tendon grafting on the morphological changes to the bone tunnels at the aperture 1 year after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: Seventy-three patients were randomized to undergo the CaP (n = 37) or the conventional method (n = 36). All patients underwent computed tomography (CT) evaluation 1 week and 1 year post-operatively. The femoral and tibial tunnels at the aperture were evaluated on reconstructed 3D CT images. Changes in the cross-sectional area (CSA) and diameters of the femur and the tibia, and the translation rate of the tunnel walls and the morphological changes of both tunnels were assessed. RESULTS: There was a significant reduction in the increase in the CSA and the anterior-posterior and proximal-distal tunnel diameters on the femoral side in the CaP group as compared with the conventional group. On the femoral side, the translation rate of the posterior wall was significantly larger in the CaP group than in the conventional group, whereas the translation rate of the distal wall was significantly smaller in the CaP group than in the conventional group. CONCLUSIONS: As compared with the conventional method, the CaP-hybridized tendon graft reduced bone tunnel enlargement on the femoral side 1 year after anatomic single-bundle ACL reconstruction due to an anterior shift of the posterior wall and reduced distal shift in the femoral bone tunnel. Clinically, the CaP-hybridized tendon grafts can prevent femoral bone tunnel enlargement in anatomic single-bundle ACL reconstruction. LEVEL OF EVIDENCE: I.

Impact of Surgical Timing on Functional Outcomes after Anterior Cruciate Ligament Reconstruction.

Objectives: Although acute anterior cruciate ligament reconstruction (ACLR) is often avoided because of postoperative joint stiffness, delayed ACLR can lead to a longer recovery time and can have a negative impact on physical function due to detraining. This study aimed to determine the effects of acute ACLR on postoperative outcomes, including muscle strength, performance, and return to sports. Methods: A total of 110 patients who underwent anatomical ACLR using hamstring autografts were included in this study and were divided into three groups: acute (ACLR performed within 2 weeks after ACL injury), 2-6 weeks (ACLR performed between 2 and 6 weeks after injury), and 6-12 weeks (ACLR performed between 6 and 12 weeks after injury). Several parameters were evaluated, including range of motion, knee joint stability, isokinetic knee strength, performance, and return to sports. Results: No significant differences were found in the range of motion or knee joint stability between the groups. The acute group exhibited significantly greater quadriceps strength at 3 months postoperatively than the other groups (p < 0.05). The single-leg hop test showed that 66.7%, 38.7%, and 33.3% of the patients in the acute, 2-6 weeks, and 6-12 weeks groups, respectively, recovered to an LSI of 90% or greater (p = 0.09, Cramer's V = 0.27). All patients in the acute group were able to return to sports (p = 0.14; Cramer's V = 0.28). Conclusions: Acute ACLR is advantageous for the early recovery of strength and performance without adverse events. Acute ACLR may shorten the time spent away from sports activities.

Assessing the Influence of the COVID-19 Pandemic on Gastric Cancer Mortality Risk.

BACKGROUND: The global impact of the coronavirus disease 2019 (COVID-19) pandemic on public health has been significant. Upper gastrointestinal endoscopy for screening and diagnosis decreased along with new gastric cancer (GC) diagnoses. METHODS: This study assesses how the pandemic affected GC mortality using data from Hiroshima Prefecture, comparing mortality rates between patients diagnosed during the pandemic (2020 and 2021) and pre-pandemic (2018 and 2019) periods. The crude hazard ratios (HRs) and HRs adjusted for age, sex, clinical stage, treatment status, and travel distance to the nearest GC screening facility were estimated using Cox regression models. Subgroup and sensitivity analyses were also performed. RESULTS: A total of 9571 patients were diagnosed, with 4877 eligible for follow-up. The median age was 74 years, and 69% were male. The median follow-up period was 157 days, with events per 1000 person-years at 278 and 374 in the pre-pandemic and pandemic periods, respectively (crude HR, 1.37; adjusted HR, 1.17). The sensitivity and subgroup analyses yielded consistent results. CONCLUSIONS: The COVID-19 pandemic increased mortality risk in patients with GC. Further studies are required to observe long-term outcomes and identify the disparities contributing to the increased mortality risk.

Use of Unidirectional Porous ß-Tricalcium Phosphate in the Tibial Tunnel for Anterior Cruciate Ligament Reconstruction: A Case Series.

Bone defects in the tibial tunnel for anterior cruciate ligament (ACL) reconstruction can cause adverse events. The unidirectional porous tricalcium ß-phosphate (UDPTCP) has the potential to be used as a filling substitute for bone defects. In this case series, we present the first nine cases in which UDPTCP was used as a bone substitute in the tibial tunnel during ACL reconstruction. The patients comprised six males and three females, with an average age of 32 years (range: 16-50 years). A cylindrical UDPTCP measuring 10 x 20 mm was molded to fit the tibial tunnel and then implanted. At the one-year postoperative follow-up, none of the patients demonstrated any complications, and bone remodeling was observed on radiographs. Therefore, UDPTCP may provide a safe and reliable filling substitute for the tibial tunnel in ACL reconstruction.

Impact of the COVID-19 pandemic on the mortality among patients with colorectal cancer in Hiroshima, Japan: A large cancer registry study.

BACKGROUND: This retrospective cohort study aimed to evaluate the impact of the COVID-19 pandemic on colorectal cancer care and mortality using a large cancer registry in Hiroshima Prefecture, Japan. The study aimed to estimate the all-cause mortality rates within 1 year of diagnosis among colorectal cancer patients diagnosed during the pandemic period (2020 and 2021) compared to those diagnosed during the pre-pandemic period (2018 and 2019). METHODS: The day of diagnosis was set as Day 0 and Cox regression models were utilized to estimate crude hazard ratios (HRs) and adjusted HRs, accounting for age, sex, cancer stage, and treatment status. Two sensitivity analyses of overall survival were performed with different cutoffs of the pre-pandemic/pandemic periods and year-to-year comparisons. Subgroup analyses were performed using likelihood ratio tests. RESULTS: A total of 15,085 colorectal cancer patients were included, with 6499 eligible for follow-up. A median age of included patients was 72 years old, of which 59% were male. The distribution of cancer stages showed little variation between the pre-pandemic and pandemic periods. With a median follow-up of 177 days, the number of events was 316/3111 (173 events per 1000 person-years [E/1000PY], 95% confidence interval [CI]: 154-192 E/1000PY) in the pre-pandemic period, and 326/2746 (245 E/1000PY, 95% CI: 220-274 E/1000PY) in the pandemic period (crude HR: 1.42, 95% CI: 1.22-1.66; adjusted HR: 1.25, 95% CI: 1.07-1.46). The two sensitivity analyses and subgroup analyses consistently supported these findings. CONCLUSIONS: The study revealed an increased colorectal cancer mortality during the pandemic period, suggesting a continuous impact of the COVID-19 pandemic on the known and unknown risk factors for colorectal cancer for several years. Further studies are necessary to mitigate the adverse effects on patient outcomes.

How the 2018 Japan Floods Impacted Nursing Home Admissions for Older Persons: A Longitudinal Study Using the Long-Term Care Insurance Comprehensive Database.

OBJECTIVES: As disasters become more frequent because of global warming, countries across the world are seeking ways to protect vulnerable older populations. Although these conditions may increase nursing home admission (NHA) rates for older persons, we know of no studies that have directly tested this hypothesis. DESIGN: This was a retrospective cohort study. SETTING AND PARTICIPANTS: We analyzed data from long-term care insurance (LTCI) users in 3 Japanese prefectures that incurred heavy damage from the 2018 Japan Floods, which is the largest recorded flooding disaster in national history. Specifically, we extracted NHA data from the LTCI comprehensive database, both for disaster-affected and unaffected individuals. METHODS: We employed the Cox proportional hazards model to calculate multivariate-adjusted hazard ratios (HRs) for NHAs within a 6-month period following the 2018 Japan Floods, with adjustments for potential confounding factors. RESULTS: Of the 187,861 individuals who used LTCI services during the investigated period, we identified 2156 (1.1%) as disaster affected. The HR for NHA was significantly higher for disaster-affected (vs unaffected) individuals (adjusted HR 3.23: 95% CI 2.88‒3.64), and also higher than the HRs for older age (90-94 years vs 65-69 years: 2.29, CI 1.93‒2.70), cognitive impairment (severe impairment vs normal: 1.40, CI 1.25‒1.57), and physical function (bedridden vs independent: 2.27, CI 1.83‒2.70). According to our subgroup analyses, the adjusted HR for disaster-affected individuals unable to feed themselves was 6.00 (CI 3.68‒9.79), with a significant interaction between the 2 variables (P = .01). CONCLUSIONS AND IMPLICATIONS: Natural disasters increase the risk of NHA for older persons, especially those who are unable to feed themselves. Health care providers and policymakers should understand and prepare for this emerging risk factor.

Impact of the early phase of COVID-19 on the trends of isolated bacteria in the national database of Japan: an interrupted time-series analysis.

OBJECTIVES: During the coronavirus disease 2019 (COVID-19) pandemic, a change in the trend of infections was observed. However, there are few reports comprehensively assessing the impact of the early phase of COVID-19 on the trend of bacteria isolated. METHODS: We extracted the number of positive cultures of hospitalized patients for approximately 200 institutions using the Japanese national database. The outcome was the ratio of 10 species isolated in comparison to the total isolates for each month. Interrupted time-series analyses were conducted between 13 (from Jan-2019 to Jan-2020) and 8 (from May-2020 to Dec-2020) monthly data points. RESULTS: A total of 369,210 isolates were involved. Differences in the level change for Streptococcus pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes decreased significantly by 0.272 (95% confidence interval [CI]:0.192-0.352), 0.244 (95%CI:0.174-0.314), and 0.324 (95%CI:0.06-0.589), respectively. Bacteria transmitted by contact infection, such as Staphylococcus aureus, did not decrease. Differences in slope change were not significant in all species. CONCLUSIONS: The ratios of isolated bacteria transmitted by droplet infection decreased immediately after the early phase of COVID-19 and maintained the same level. The awareness and behavioral changes toward increased COVID-19 prevention might have a substantial impact on the prevention of bacterial infections, especially droplet infections.

Effect of COVID-19 inpatients with cognitive decline on discharge after the quarantine period: A retrospective cohort study.

Background: A new SARS-CoV-2 variant, Omicron, was reported on November 14, 2021, and it altered the COVID-19 epidemic with a different peak timing by region in Japan. Residents in the Hiroshima prefecture, especially the vulnerable elderly, were threatened by this wave in advance of many other prefectures. We evaluated the effect of cognitive decline on discharge extension after the quarantine period. Methods: Participants of this retrospective cohort study were patients who were admitted to the care unit for COVID-19 treatment at Hiroshima University Hospital between January 1, 2022, and March 1, 2022 (60 days). Our primary outcome was the extended length of stay (LOS) in the hospital after the quarantine period (10 days after onset). A negative binomial regression analysis was performed to assess the extended LOS of patients with cognitive decline, adjusting for age classification, gender, and severity of COVID-19. Results: The total number of participants was 74. Per the level of cognitive function, there were 56 independent participants, 5 mild declines, and 13 severe declines. For the negative binomial regression analysis, the exponentiated coefficient of mild cognitive decline was 3.05 (95% confidential interval [CI]: 1.43-6.49) and that of severe cognitive decline was 1.95 (95% CI: 1.09-3.53). Conclusions: Mild cognitive decline and severe cognitive decline elevated the risk of extended LOS after COVID-19 patients finished the quarantine period.

Utility of axial magnetic resonance images for detecting meniscal ramp lesions associated with anterior cruciate ligament injuries.

Background: Ramp lesions (RLs), associated with anterior cruciate ligament (ACL) injuries, should be repaired to ensure postoperative knee stability. However, it is difficult to identify all RLs before surgery using conventional sagittal magnetic resonance (MR) images and arthroscopy from the anterior, medial, and lateral portals that are usually used during ACL reconstruction. We report the effectiveness of axial images for detecting RL. Methods: From January 2018, a total of 316 knees underwent primary ACL reconstruction with preoperative magnetic resonance imaging (MRI) examination at our hospital. Among these, 149 knees, which required meniscal suturing at the same time, were retrospectively investigated. This study evaluated 22 knees with confirmed RLs around the posterior horn of the medial meniscus. The effectiveness of the preoperative sagittal and axial MR images for detecting RL was assessed. With the MR image, a three-dimensional double-echo steady-state image with a flip angle of 25° was reconstructed into the sagittal and axial planes, respectively. Reconstructed images with 3-mm slices for sagittal slices and 1-mm slices for axial sections were used. The diagnosis was made based on the presence of RL (RL was present, RL may be present, and RL was not present) by four knee surgeons with more than 10 years of experience. Results: Approximately 53% of knee cases were diagnosed with RLs using sagittal images. Meanwhile, a diagnosis was achieved using axial images in 89% of cases. Conclusion: Axial MRI may be superior in detecting RLs.

Intravenous lobular capillary haemangioma presenting as neck discomfort associated with neck anteflexion.

Lobular capillary haemangioma, also known as pyogenic granuloma, is a benign vascular tumour that usually originates in the skin and mucosal membrane. It sometimes derives from the lumen of a vein and the clinical presentations are various and non-specific. A 72-year-old woman complained of a sensation of pressure in her left neck for 1 month when cooking. Her left cephalic vein was enlarged with no signs of oedema, and cervical ultrasound revealed a space-occupying lesion in the left subclavian vein. Contrast-enhanced CT and MRI revealed an intravascular tumour. This tumour was removed with operation, and histopathological examination revealed intravascular capillary haemangioma. Intravascular lobular capillary haemangioma is a rare condition that occurs in the veins of the neck and upper extremities. Intravascular tumours could cause a unique symptom, such as neck discomfort associated with neck anteflexion.

Cell death and cell proliferation in cartilage layers in human anterior cruciate ligament tibial insertions after rupture.

The purpose of this study is to investigate cellular responses and histological changes of cartilaginous layers in human anterior cruciate ligament (ACL) tibial insertions after rupture compared with those in normal insertions. Fully 16 tibial insertions of ruptured ACLs were obtained during primary ACL reconstructions. We also obtained 16 normal ACL tibial insertions from cadavers. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) to detect apoptosis, proliferating cell nuclear antigen (PCNA) staining, and histological examination were performed. The percentage of TUNEL-positive chondrocytes in ruptured ACL insertions (30.2 +/- 15.6%) was higher than that in normal insertions (9.6 +/- 5.8%). The percentage of PCNA-positive chondrocytes was significantly different between ruptured ACL insertions (19.9 +/- 15.0%) and normal insertions (12.3 +/- 7.3%). The average thickness of the cartilage layer, the glycosaminoglycan-stained area, and the number of chondrocytes per millimeter in ruptured ACL insertions was smaller than those in normal insertions. The decrease in the number of chondrocytes owing to an imbalance between cell death and cell proliferation in the ACL insertions after rupture, as compared with normal insertions, may lead to histological changes of the cartilage layer in the insertions. An in-depth understanding of injured ACL insertion may help elucidate the etiology of histological changes and the function and significance of the existence of the cartilage layer of insertion. This understanding may help in developing optimal treatment protocols for ACL injuries if apoptosis and cell proliferation are controlled.

Morphological changes in the femoral and tibial bone tunnels after anatomic single-bundle anterior cruciate ligament reconstruction using a calcium phosphate-hybridized tendon graft in 2years of follow-up.

INTRODUCTION: A calcium phosphate (CaP)-hybridized tendon graft improves tendon-to-bone healing. The purpose of the study was to evaluate the progression of morphological changes in the femoral and tibial bone tunnels after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction using the CaP-hybridized tendon graft versus an untreated tendon graft during 2 years of follow-up. HYPOTHESIS: We hypothesized that the CaP-hybridized tendon graft would prevent the progression of bone tunnel enlargement compared with the untreated tendon graft. PATIENTS AND METHODS: The CaP group comprised 19 patients, while the conventional group comprised 18. Computed tomography was performed at postoperative 1 week, 1 year, and 2 years. The bone tunnel enlargement and tunnel translation at the aperture of the femoral and tibial tunnels were analyzed. RESULTS: In the CaP group, the femoral bone tunnel did not expand during 2 years of follow-up. In the conventional group, the femoral bone tunnel diameters at postoperative 1 year and 2 years were enlarged compared with postoperative 1 week, and the proximal and distal walls of the femoral bone tunnel shifted proximally and distally, respectively. The femoral bone tunnel in the CaP group was smaller than that in the conventional group at 1 year postoperatively. Although the tibial bone tunnels expanded for up to 1 year postoperatively in both groups, the expanded bone tunnel reduced during 2 years of follow-up only in the CaP group. DISCUSSION: In anatomic single-bundle ACL reconstruction, the femoral bone tunnel in the CaP group did not expand or progress with time compared with the conventional group, while the tibial bone tunnel in the CaP group expanded for up to 1 year postoperatively and then reduced for up to 2 years postoperatively. The CaP-hybridized tendon can prevent the progression of bone tunnel enlargement. LEVEL OF EVIDENCE: Level II, Low-powered prospective randomized trial.

Failure risks in anatomic single-bundle anterior cruciate ligament reconstruction via the outside-in tunnel technique using a hamstring autograft.

PURPOSE: To retrospectively evaluate the failure risk factors in anatomic single-bundle anterior cruciate ligament (ACL) reconstruction via outside-in tunnel technique using a hamstring autograft, and investigate the relationship between each risk factor. METHODS: The patients who underwent the ACL reconstruction with a minimum 1-year follow-up were included. We divided the patients into two groups - those who experienced graft failure (the failure group) and those who did not experience graft failure (the no failure group) - and compared their age, height, weight, sports activity level, graft size, and muscle strength. We defined graft failure as patients who underwent revision ACL reconstruction or had a second injurious ACL episode and those with a graft grade of C or D based on the International Knee Documentation Committee score. RESULTS: The study included 232 patients (101 male, 131 female; mean age at operation was 26.1 ±â€¯11.9 years). The failure rate was 11.6% (failure group: 27 patients; no failure group: 205 patients). The patients in the failure group were younger and had higher sports activity level than those in the no failure group. (p < 0.001 and p < 0.001, respectively). Patient body weight in the failure group was lower than that in the no failure group (p = 0.047). Regarding the graft size of the tibial side, the failure group had smaller graft sizes than the no failure group (p = 0.030). With respect to muscle strength, quadriceps strength 6 months after surgery in the failure group was stronger than that in the no failure group (p = 0.001). In addition, the hamstring/quadriceps strength (H/Q) ratios 3 and 6 months after surgery were lower in the failure group than that in the no failure group (p = 0.041 and p = 0.001, respectively). There was an association between the age and the body weight, between the body weight and the graft size of the tibial side, and between lower age and high sports activity. Moreover, the high quadriceps strength at 6 months and the low H/Q ratio at 3 months were related to the low H/Q ratio at 6 months. CONCLUSION: Young age, high activity sports level, low body weight, small graft diameter of the tibial side, high quadriceps strength at 6 months, and low H/Q ratio at 3 and 6 months can be failure risk factors in anatomic single-bundle ACL reconstruction via the outside-in tunnel technique using a hamstring autograft.