The patellar ligament: A comprehensive review

The patellar ligament (PL) is an epiphyseal ligament and is part of the extensor complex of the knee. The ligament has gained attention due to its clinical relevance to autograft and tendinopathy. A variety of anatomical variations of the PL such as aplasia, numerical variations, and vascularity are being reported recently by clinicians and anatomists. The aim of this literature was to review the available literature to provide a consensus regarding anatomic variations of the PL, neurovasculature surrounding the PL, histology of the PL, and various aspects of PL measurements with relevance to the surgical considerations and sex and age-related differences. A narrative review of the patellar ligament was performed by conducting a detailed literature search and review of relevant articles. A total of 90 articles on the patellar ligament were included and were categorized into studies based on anatomical variations, neurovasculature, morphometrics, microanatomy, sex and age-related difference, and ACL reconstruction. The anatomical variations and morphometrics of the PL were found to correlate with the frequency of strain injuries, tendinopathy, and efficacy of the PL autograft in anterior cruciate ligament reconstruction. The sex differences in PL measurements and the effect of estrogen on collagen synthesis explained a higher incidence of patellar tendinopathy in women. An awareness of its variations enables careful selection of surgical incisions, thereby avoiding complications related to nerve injury. Accurate knowledge of the PL microanatomy assists in understanding the mechanism of ligament degeneration, rupture, autograft harvesting, and ligamentization results.     

关节镜双后内入路与切开手术治疗急性单纯后交叉韧带胫骨止点撕脱骨折早期疗效对比

目的:比较关节镜双后内入路与切开手术治疗急性单纯后交叉韧带胫骨止点撕脱骨折的疗效差异。方法:回顾性分析2016年6月至2020年6月经手术治疗的52例急性单纯性后交叉韧带胫骨止点撕脱骨折患者的临床资料,按手术方案不同分为两组,关节镜组27例患者行关节镜双后内入路手术治疗,其中男16例,女11例,年龄19~52(34.9±9.2)岁;切开复位组25例患者行膝关节后内侧切口手术治疗,其中男14例,女11例,年龄18~54(33.7±8.4)岁。观察并比较两组患者手术时间、切口长度、术中出血量、住院时间、住院费用、术后愈合情况、并发症以及术后12个月Lysholm、IKDC评分。结果:两组患者均顺利完成手术,无血管、神经损伤。52例均获得随访,时间6~24(15.0±1.7)个月。关节镜组手术时间、住院费用大于切开复位组(P<0.05);关节镜组术中出血量、切口长度、住院时间小于切开复位组(P<0.05);关节镜组和切开复位组术后12个月Lysholm评分分别为(95.9±1.7)分和(86.4±1.2)分,均较术前的(49.1±2.3)分和(48.9±1.1)分显著提高(P<0.05);关节镜组和切开复位组术后12个月IKDC总分分别为(96.9±1.5)分和(87.1±1.4)分,均较术前的(47.6±4.1)分和(48.1±3.9)分显著提高(P<0.05);关节镜组术后12个月膝关节Lysholm、IKDC评分均高于切开复位组(P<0.05)。结论:关节镜双后内入路治疗急性单纯后交叉韧带胫骨止点撕脱骨折,早期效果满意,疗效优于传统开放手术,具有创伤小、恢复快、操作简便等优点。     

核因子κB受体活化因子配体和肿瘤坏死因子α经炎性牙周膜干细胞外泌体促进破骨细胞分化

目的　慢性牙周炎表现的病理性骨吸收非常常见，牙周膜干细胞（PDLSCs）的外泌体（Exo）对骨吸收的作用和影响尚不明确，本研究分析了该Exo蛋白组分对破骨细胞分化的影响。方法　分别从正畸前拔牙患者和慢性牙周炎患者的牙周膜组织中提取PDLSCs，通过流式细胞术检测表面标记物；通过差速离心分别提取2种细胞的Exo，即Exo-WT和Exo-CP，并通过Western blot、透射电子显微镜（TEM）、蛋白浓度检测、纳米粒径追踪检测Exo特征；通过蛋白质谱检测2种Exo的蛋白组分；通过酶联免疫吸附（ELISA）验证了差异表达蛋白肿瘤坏死因子α（TNF-α）、核因子κB受体活化因子配体（RANKL）、白细胞介素（IL）-1α、转化生长因子β（TGF-β）、骨形态发生蛋白2（BMP-2）表达水平；将10、100、1 000 μg·mL^-1的Exo-CP或Exo-WT加入RAW264.7培养基中并于5 d时通过实时荧光定量聚合酶链反应（RT-qPCR）、Western blot、抗酒石酸酸性磷酸酶（TRAP）染色检测破骨分化相关指标表达情况；采用SPSS 24.0软件对实验数据进行统计学分析。结果　Exo-CP富集的差异表达蛋白主要与破骨细胞分化的TNF信号通路、核转录因子κB（NF-κB）信号通路相关；ELISA实验证实了Exo-CP中高表达TNF-α、RANKL、IL-1α，低表达TGF-β1、BMP-2（P<0.05）；Exo-CP作用于RAW264.7，显著提高了细胞的破骨分化相关基因及蛋白的表达水平，TRAP染色可见分化的破骨细胞，且呈现浓度依赖性，100、1 000 μg·mL^-1浓度Exo-CP对破骨细胞分化的促进作用显著高于10 μg·mL^-1浓度组（P<0.05）。结论　慢性牙周炎的病理性骨吸收可能由炎性PDLSCs所分泌的Exo通过促进破骨细胞分化引起，Exo中主要的作用蛋白可能为RANKL和TNF-α，本研究为慢性牙周炎骨吸收的发病机制提供了新视角。     

Isokinetic quadriceps symmetry helps in the decision to return to running after anterior cruciate ligament reconstruction

BackgroundAfter anterior cruciate ligament reconstruction (ACLR), the decision to allow a return to running is empirical, and the post-operative delay is the most-used criterion. The Quadriceps isokinetic-strength Limb Symmetry Index (Quadriceps LSI), with a cutoff of 60%, could be a useful criterion.ObjectiveTo determine the association between a Quadriceps LSI ≥ 60% and return to running after ACLR.MethodsOver a 10-year period, we retrospectively included 470 patients who underwent ACLR. Four months after ACLR, participants performed an isokinetic test; quadriceps concentric peak torque was used to calculate the Quadriceps LSI at 60?/s. With a Quadriceps LSI ≥ 60%, a return to running was suggested. At 6 months after ACLR, participants were clinically evaluated for a return to sport and post-operative middle-term complications. A multivariable predictive model was built to assess the efficiency diagnosis of this cutoff in order to consider cofounding factors. Quadriceps LSI cutoff ≥ 60% was assessed with sensitivity, specificity and the area under the receiver operating characteristic curve (AUC).ResultsAccording to our decision-making process with the 60% Quadriceps LSI cutoff at 60?/s, 285 patients were authorized to return to running at 4 months after ACLR and 185 were not, but 21% (n = 59) and 24% (n = 45), respectively, were not compliant with the recommendation. No iterative autograft rupture or meniscus pathology occurred at 6 months of follow-up. On multivariable logistic regression analysis, a return to running by using the 60% Quadriceps LSI cutoff was associated with undergoing the hamstring strand procedure (odds ratio 2.60, 95% confidence interval [CI] 1.75–3.84; P < 0.0001) and the absence of knee complications (1.18, 1.07–1.29; P = 0.001) at 4 months. The sensitivity and specificity of the 60% Quadriceps LSI cutoff were 83% and 70%, respectively. The AUC was 0.840 (95% CI 0.803–0.877).ConclusionsUsing the 60% cutoff of the isokinetic Quadriceps LSI at 4 months after ACLR could help in the decision to allow a return to running.     

Low percentage of patients passed the ‘Back in Action’ test battery 9 months after bone-patellar tendon-bone anterior cruciate ligament reconstruction

BackgroundAnterior cruciate ligament (ACL) reconstruction is recommended in patients who intend to return to high-level sports. However, there is only a 55–80% return to pre-injury level of sports after ACL reconstruction, with a re-injury rate up to 20%. The aim of this study was to determine the percentage of patients passing the Back in Action (BIA) test 9 months after primary bone-patellar-tendon-bone (BPTB) ACL reconstruction, and evaluate the association between passing the BIA test and patient reported outcome measurements (PROMs).MethodsPatients underwent the BIA test 9 months after BPTB ACL reconstruction. In total 103 patients were included. Passing the BIA test (PASSED-group) was defined as a normal or higher score at all sub-tests with limb symmetry index (LSI) ≥90% for the dominant leg and LSI >80% for the non-dominant leg. Patients who did not meet these criteria were defined as the FAILED-group. PROMs included the International Knee Documentation Committee, Knee injury Osteoarthritis Outcome Score and Anterior Cruciate Ligament-Return to Sport after Injury.ResultsEighteen patients (17.5%) passed the BIA test 9 months after BPTB ACL reconstruction. PROMs were not statistically significant different between the PASSED- and FAILED-group.ConclusionLow percentage of patients passed the BIA test 9 months after BPTB ACL reconstruction. Although current PROMs cut-off values were met, the BIA test results show persistent functional deficits. Therefore, the BIA test could be of additional value in the decision-making process regarding return to sport (RTS). This study highlights the need for additional rehabilitation as RTS in a condition of incomplete recovery may increase the risk of re-injury.Level of evidenceII.     

Bilateral changes in knee joint laxity during the first year after non-surgically treated anterior cruciate ligament injury

ObjectivesAnalyse changes in knee laxity between 3, 6, 12 and 24 months after non-surgically treated ACL injury and to analyse associations between knee laxity and knee function, self-reported knee stability, ACL-Return to Sport after Injury (ACL-RSI), fear and confidence at different timepoints during recovery.DesignProspective cohort study.Participants125 patients (67 males, mean age 25.0 ± 7.0 years) with acute ACL injury.Main outcomeLaxity was measured using KT-1000 arthrometer. Self-reported knee function was assessed using the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). Confidence and fear were assessed with questions from the ACL-RSI scale. Subjectively knee stability was assessed using SANE.ResultsKnee laxity increased bilaterally from 3 to 12 months, and in the non-involved knee from 3 to 24 months (p˂0.05), although mean change was below 1 mm. Side-to-side difference in knee laxity was correlated with IKDC-SKF (r = −0.283) and knee stability in rehabilitation/sport activities (r = −0.315) at 6 months, but not with confidence/fear.ConclusionKnee laxity increased bilaterally during the first year after non-surgically treated ACL injury, though, the mean change in knee laxity was below 1 mm and the clinical significance is unknown. Knee laxity was weakly associated with knee function and perceived knee stability.Level of evidenceLevel IITrial registrationNCT02931084     

Effects of cognitive- and motor-dual tasks on postural control regularity following anterior cruciate ligament reconstruction

BackgroundHigh injury rates following anterior cruciate ligament reconstruction (ACLR) motivate the need to better understand lingering movement deficiencies following return to sport. Athletic competition involves various types of sensory, motor, and cognitive challenges; however, postural control deficiencies during this spectrum of conditions are not well understood following ACLR.Research questionTo what extent is postural control altered following ACLR in the presence of sensory, motor, and cognitive challenges, and does postural control correlate with patient-reported symptoms?MethodsFourteen individuals following ACLR (4 m/10 f, 21.2 ± 2.4 yr, 76.9 ± 19.1 kg, 1.70 ± 0.14 m) and fourteen matched healthy controls (4 m/10 f, 21.2 ± 1.4 yr, 75.4 ± 15.3 kg, 1.70 ± 0.15 m) participated in the study. Participants completed single-leg balance, ACLR limb or matched side for controls, under four conditions: 1) eyes open, 2) eyes closed, 3) visual-cognitive dual task (i.e., reverse digit span), and 4) motor dual task (i.e., catching a ball). Sample entropy (SEn) was calculated for each balance condition to characterize regularity of center of pressure control. Participants also completed patient-reported outcomes to characterize self-reported knee function, symptoms, and fear. A mixed effects model tested for differences in SEn between balance conditions, and Spearman correlations tested for relationships between SEn and patient-reported outcomes.ResultsA significant Group-by-Condition interaction was detected (P = 0.043). While the motor dual task and eyes closed balance conditions were associated with the lowest SEn for both groups, only the visual-cognitive dual task condition demonstrated a significant difference between groups, with the ACLR group having lower SEn [95% confidence interval for ΔSEn: (0.03, 0.35)]. Lower KOOS-Sport scores were associated with decreased SEn for the ACLR group (ρ = 0.81, P < 0.001).SignificanceThese findings are consistent with ACLR individuals using a less automatic approach to postural control compared to controls, particularly when presented with a visual-cognitive challenge. Altered neuromuscular control persists well after ACLR surgery and can be related to patient-reported outcomes.     

左上侧切牙Ⅲ型牙内陷牙髓及牙周联合治疗1例

本文报告1例因牙齿根面畸形导致严重根尖病变及牙周破坏的牙周牙髓联合病变的左上侧切牙,瘘道长期不愈,腭侧窄而深牙周袋,严重根尖病变及牙槽骨垂直吸收。通过显微根管治疗、根尖手术、引导牙周组织再生术治疗,实现了控制根尖及牙周感染,达到了保留患牙的目的。