Influence of tibial tuberosity position and trochlear depth on patellar tracking in patellar instability: Variations with Patella Alta

BackgroundPatella alta reduces articular constraints acting on the patella from the trochlear groove with the knee extended. The current study was performed to address how patella alta alters the influence of tibial tuberosity position and trochlear depth on patellar tracking in patients being treated for patellar instability.MethodsFifteen subjects with recurrent patellar instability participated in knee extension within a dynamic CT scanner. Computational models were reconstructed from the motions to characterize patellar lateral shift, patellar tilt, patellar height, trochlear depth and lateral position of the tibial tuberosity at 0° and 30° of knee flexion. Linear regressions were used to correlate patellar tracking with anatomy for an alta group (7 knees, Caton-Deschamps index > 1.2) and a non-alta group.FindingsFor the alta group, lateral patellar shift and tilt increased with increasing lateral position of the tibial tuberosity at 0° (r² > 0.8, P < 0.005). For the non-alta group, lateral patellar shift and tilt increased as depth of the groove decreased at 0° (r² > 0.8, P = 0.001). Lateral patellar tilt also increased with increasing lateral position of the tibial tuberosity at 30° for the non-alta group (r² = 0.55, P = 0.04).InterpretationFor patients with patellar instability, lateral patellar maltracking with the knee extended can be largely attributed to either a shallow trochlear groove or a combination of patella alta and a lateral position of the tibial tuberosity. These relationships should be considered in both conservative and surgical treatment planning.     

应用缝匠肌治疗伸膝功能障碍

Theusualtreatmentofdislocationorsubluxationofpatella，quadricepsfemorisparalysisafterpoliomyelitisaswellasweakex－tensorofkneeafterquadriceps－plastyonextensionstiffnessofkneeandafterpatellectomyresultedfromcomminutedfractureortuber－culosisofpatellawasfarfromsatisfied．Freeingthedistalone－thirdpartofsartoriusmusclewithoutcuttingitsinsertionfortreatmentoftheoutwardsdisplacementofpatellaandfreeingthedistaltwo－thirdspartofsartoriusmusclewithoutcuttingitsinsertionfortreatmenttheweakextensorofkne…     

A patient-specific model of total knee arthroplasty to estimate patellar strain: A case study

BackgroundInappropriate patellar cut during total knee arthroplasty can lead to patellar complications due to increased bone strain. In this study, we evaluated patellar bone strain of a patient who had a deeper patellar cut than the recommended.MethodsA patient-specific model based on patient preoperative data was created. The model was decoupled into two levels: knee and patella. The knee model predicted kinematics and forces on the patella during squat movement. The patella model used these values to predict bone strain after total knee arthroplasty. Mechanical properties of the patellar bone were identified with micro-finite element modeling testing of cadaveric samples. The model was validated with a robotic knee simulator and postoperative X-rays. For this patient, we compared the deeper patellar cut depth to the recommended one, and evaluated patellar bone volume with octahedral shear strain above 1%.FindingsModel predictions were consistent with experimental measurements of the robotic knee simulator and postoperative X-rays. Compared to the recommended cut, the deeper cut increased the critical strain bone volume, but by less than 3% of total patellar volume.InterpretationWe thus conclude that the predicted increase in patellar strain should be within an acceptable range, since this patient had no complaints 8 months after surgery. This validated patient-specific model will later be used to address other questions on groups of patients, to eventually improve surgical planning and outcome of total knee arthroplasty.     

髌骨轴位摄影角度与屈膝角度的相关性

目的 探讨髌骨轴位摄影角度与屈膝角度的相关性.方法 选取30例患者的标准髌骨侧位膝关节屈膝过程的动态影像.在髌骨侧位动态影像中,以股骨前缘线与胫骨前缘线的夹角作为胫股角,以股骨前缘线与髌骨后缘线的夹角作为髌股角(X线入射角度),选择胫股角为50°～170°,每隔5°分别测量对应的髌股角.统计各胫股角相对应的髌股角的均值,对测量数据进行相关分析和回归分析.结果 胫股角在50°～110°范围时,胫股角和髌股角存在直线相关关系(r=0.92,P<0.01),回归方程为Y=60.71+0.60X.胫股角在115°～170°范围时,胫股角与髌股角的差值(髌胫角)基本恒定,其均值为15.04°±3.76°.结论 髌骨轴位摄影角度与胫股角具有直线相关性,在髌骨轴位摄影中可根据回归方程Y=60.71+0.60X或15°角选择相应的摄影角度.     

The micro-current stimulation of knee acupoints in management of chondromalacia patella: a case report

[Purpose] A case report in which we treated injured patellar cartilage using non-invasive electrical stimulation; we also used MRI to document the morphology of the patellar cartilage before and after the treatment. [Participant and Methods] A police officer suffered from right anterior knee pain that noticeably affected his firearms marksmanship in kneeling position. After a MRI scan he was diagnosed with grade I chondromalacia patella involving the lateral patellar facet. He received therapeutic electrical stimulation on right knee acupoints for four weeks. [Results] He responded positively to the treatment and his numerical rating scale reduced from 6 to 0 for the right knee pain. The MRI revealed that the signs of grade I chondromalacia patella disappeared. [Conclusion] The patellar cartilage is largely avascular; the chondrocytes in cartilage have a low metabolic rate due to limited nutrient supply. Mild cartilage repair may occur spontaneously but is undoubtedly slow. Although this is a case report, we believe that the micro-current stimulation may help enhance the local metabolism and repair process in the affected cartilage.Key words: Electrical stimulation, Patellofemoral joint, Acupuncture point     

Changes in patellofemoral joint contact pressures caused by vastus medialis muscle weakness

Background

Patellofemoral joint pain is a common knee disorder, but its underlying causes remain unknown. One proposed mechanism is an imbalance in force in the knee extensor muscles. Specifically, the vastus medialis and vastus lateralis are thought to play a crucial role in proper patellar tracking, and weakness in vastus medialis is thought to lead to a lateral shift in the patella causing increased contact pressures and pain. The purpose of this study was to create an animal model of vastus medialis weakness and to test the effect of this weakness on patellofemoral contact pressures.

Methods

Experiments were performed using New Zealand white rabbits (mass 4.9–7.7 kg, n = 12). Loading of the patellofemoral joint was produced by femoral nerve stimulation of the knee extensor muscles. Knee extensor imbalance was produced by vastus medialis ablation. Fuji pressure sensitive film was used to record contact area, shape and pressures for maximal and sub-maximal, matched-force contractions at knee angles of 30°, 60°, and 90°.

Findings

Patellofemoral peak pressures, average pressures, contact areas and contact shapes were the same across all loading conditions for matched-force contractions before and after elimination of vastus medialis.

Interpretation

We conclude that vastus medialis weakness does not cause changes in patellofemoral contact pressures. Since the muscular and knee joint geometry in rabbits and humans is similar, we question the idea of vastus medialis weakness as a cause of patellar mal-tracking and patellofemoral joint pain.     

Biomechanical effects of patellar positioning on intraoperative knee joint gap measurement in total knee arthroplasty

Background

Balancing both the lateral/medial and extension/flexion joint gaps is a prerequisite for soft tissue balance in total knee arthroplasty. The purpose of this study was to quantify the effects of patellar positioning and quadriceps load during total knee arthroplasty on knee joint gap measurements.

Methods

Eight fresh-frozen cadaveric knees ranging in age from 65 to 85 years old were used. Using a medial parapatellar approach, posterior cruciate ligament sacrificing total knee arthroplasty was performed. The specimens were mounted on a custom knee testing system that allowed the femur to be locked in position for knee extension or flexion. Patellar positions of eversion, reduction, and following repair of the arthrotomy were examined. The influence of quadriceps muscle load was investigated by varying the quadriceps load from 0 to 125 N. The lateral and medial joint gaps, represented by the distance from the implanted femoral component surface to the cut tibia surface, were measured with 100 N tibial distraction force using a 3D digitizer in both extension (0°) and flexion (90°).

Findings

Both the medial and lateral joint gaps with patella eversion were significantly smaller than those with patellar reduction and arthrotomy repair (extension: all quadriceps loads, P < 0.0002; flexion: quadriceps loads less than 75 N, P < 0.0002). In patella eversion, quadriceps loading decreased the lateral joint gap more than the medial joint gap in both extension and flexion; however, the effect was greater in knee flexion with significant differences seen at all quadriceps loads, whereas in extension significant differences were only seen for quadriceps loading of 75 N and greater. Patella eversion also caused a lateral-posterior shift and external rotation of the tibia compared to the other conditions (P < 0.005). With patella reduction and repair of the arthrotomy lower quadriceps loading decreased the extension gap significantly more than the flexion gap (P < 0.01). Following repair of the arthrotomy higher quadriceps loading significantly decreased the flexion gap more than the extension gap (P < 0.04).

Interpretation

The patellar positioning and quadriceps muscle loading in total knee arthroplasty have a strong influence on intraoperative joint gap measurements.     

Quadriceps tendinopathy — a forgotten pathology for physiotherapists? A systematic review of the current evidence-base

Abstract

Background: The evidence-base surrounding the pathophysiology and management of specific tendinopathies has evolved over the past 20 years. Recent research examining lower limb tendinopathies has focussed primarily on Achilles and patellar tendon injuries. However, on further examination of the different types of patella/knee tendinopathies, confusion has arisen surrounding the diagnosis and management of patellar compared to quadriceps tendinopathy.

Objectives: The purpose of this paper was to critically examine the evidence-base surrounding the diagnosis and management of quadriceps tendinopathy.

Methods: A systematic literature search of published and unpublished literature databases was conducted to identify literature pertaining to quadriceps tendinopathy. Data from each paper were extracted to examine four key areas related to quadriceps tendinopathy: nomenclature, prevalence, assessment, and management.

Results: Twelve studies satisfied the eligibility criteria and were included in the review. On analysis, little literature has been published solely informing clinicians on the pathology, diagnosis, or management of quadriceps tendinopathy. The terms patellar tendinopathy and jumper’s knee have been incorrectly used interchangeably with quadriceps tendinopathy. Activities such as repetitive squatting and prolonged knee flexion have been associated with the development of this tendinopathy. Sports such as football and volleyball have been cited as causative factors. Quadriceps tendinopathy’s principal diagnostic feature is pain on palpation of the quadriceps/patella interface, and resisted knee extension with the knee hyperflexed. There are no clear recommendations on how to specifically treat quadriceps tendinopathy.

Conclusion: Quadriceps tendinopathy is less commn than patellar tendinopathy. Possibly as a result of this, little is known about how to assess and manage this particular knee tendinopathy. Further research is required to determine the optimal management strategy for patients diagnosed with quadriceps tendinopathy, acknowledging the biomechanical and anatomical difference of the quadriceps compared to the patellar tendon.     

Alterations in patellofemoral kinematics following vastus medialis transection in the anterior cruciate ligament deficient rabbit knee

Background

Anterior cruciate ligament deficiency and quadriceps muscle weakness are considered to be important risk factors for aberrant patellar tracking and subsequent patellofemoral osteoarthritis. However, data from in vivo experiments looking at dynamic patellar joint kinematics and muscle force are scarce. Therefore, the purpose of this study was to evaluate the effects of anterior cruciate ligament transection and loss of vastus medialis force on patellar tracking in the rabbit knee in vivo.

Methods

Eight skeletally mature New Zealand White Rabbits, weighing 6.0 kg (0.6 kg standard deviation) were used. The experimental trials consisted of active, concentric and eccentric movements of the knee joint. Measurements were performed with the intact, the anterior cruciate ligament deficient, and the vastus medialis transected knee. Patellofemoral kinematics (shift, rotation) were quantified from high speed video.

Findings

Following anterior cruciate ligament transection, patellar tracking occurred more laterally, and caused a significant lateral rotation of the patella. The addition of vastus medialis transection did not alter patellar tracking or rotation significantly for any of the force-matched experimental conditions.

Interpretation

The loss of the anterior cruciate ligament results in lateral patellar shift and rotation while the loss of vastus medialis muscle force does not affect patellar tracking or rotation in the anterior cruciate ligament deficient knee. We suggest that the current results should be considered carefully in future interpretations of knee extensor imbalance. More research is needed to describe the contribution of vastus medialis muscle strength to medial patellofemoral stability and confirm these results in the human knee.     

双能CT成像在显示膝关节韧带中的价值

目的 初步探讨双能CT成像在显示膝关节韧带中的价值.方法 对 12 例志愿者行膝关节双能CT 扫描,并均行容积显示(VRT)和多平面重建(MPR)等二维及三维图像后处理,用以显示膝关节的韧带.由2名有经验的放射科医生对图像进行分析.结果 膝关节部分韧带(膑韧带、前、后交叉韧带和腓侧副韧带)亦可清晰的显示;而较薄的韧带(胫侧副韧带)、横行的韧带(如膑内、外侧支持带)和后方的韧带(如恫斜韧带)显示欠佳.结论 双能CT是一种能够多方位、立体、直观地显示膝关节韧带的新方法,对临床应用具有一定的价值.     

The effects of axial and multi-plane loading of the extensor mechanism on the patellofemoral joint

Objective. To compare the effects of axial loading, and anatomically based multi-plane loading of the extensor mechanism on the patellofemoral joint.

Design. Repeated measures design using an in-vitro cadaver model.

Background. Since the extensor mechanism is the primary contributor to the patellofemoral joint reaction force and can affect patellar kinematics, it is essential that the forces produced by this musculature be accurately represented in a simulation model.

Methods. Patellar kinematics (magnetic tracking device), contact pressures and areas (pressure sensitive film) were measured from 6 cadaver knees under two different loading conditions: 1) axial (rectus femoris loaded in the frontal plane), and 2) multiplane (individual components of the quadriceps loaded along their respective fiber directions in both the frontal and sagittal planes). Specimens were mounted in a custom knee jig, with muscle forces being simulated using a pulley system and weights. Data were collected at 0 °, 15 °, 30 °, 45 °, 60 °, 75 ° and 90 ° of knee flexion.

Results. Compared to the axial loading condition, multi-plane loading of the vasti resulted in significantly greater contact pressure at 0 ° and significantly less contact pressure at 90 ° of knee flexion. Furthermore, the multi-plane loading condition resulted in greater lateral patellar rotation from 0–75 ° of knee flexion, and greater lateral glide at 30 ° of knee flexion. Greater patellar flexion was observed with the axial loading condition.

Conclusions. These findings indicate that axial loading of the extensor mechanism underestimates contact pressure at 0 ° and overestimates contact pressure at 90 ° of knee flexion when compared to multi-plane loading. Additionally, loading of the individual vasti appears to have an effect on patellar kinematics.     

Does navigated patellar resurfacing in total knee arthroplasty result in proper bone cut,motion and clinical outcomes?

BackgroundIn total knee arthroplasty with patellar resurfacing, patellar bone preparation, component positioning and motion assessments are still not navigated. Only femoral/tibial component positioning is supported by computer-assistance. The aim of this study was to verify, in-vivo, whether knee surgical navigation extended to patellar resurfacing, by original instrumentation and procedures for patellar-based tracking, could achieve accurate patella preparation in terms of original thickness restoration, bone cut orientation, and normal knee motion.MethodsAn additional navigation system for patellar data acquisition was used together with a standard navigation system for total knee arthroplasty in 20 patients. This supported the surgeon for patellar resurfacing via measurement of removed bone thickness, three-dimensional patellar cut orientations, and patello-femoral motion. Radiological and clinical examinations at 6 and 24-month follow-up were also performed.FindingsThe medio-lateral patellar-bone cut orientation was respectively 0.5° (standard deviation: 3.0°) and 1.4° (1.7°) lateral tilt, as measured via navigation and post-operatively on the Merchant x-ray view. The cranio-caudal orientation was 3.8° (7.2°) of flexion. The thickness variation between patellar pre- and post-implantation was 0.2 (1.3) mm. Immediately after implantation, patello-femoral as well as tibio-femoral kinematics was within the normality. Good radiological and clinical examinations at 6 and 24-month follow-up were also observed.InterpretationFor the first time, the effect of patellar navigation for its resurfacing was assessed in-vivo during surgery, with very good results for thickness restoration, proper cut orientation, and normal knee motion. These results support the introduction of patella-related navigation-based surgical procedures for computer-assisted total knee arthroplasty.     

A comparative analysis of the efficacy of anterior cruciate ligament reconstruction with autologous ligament grafting at different time points

BackgroundThis study was performed to compare the clinical efficacies of anterior cruciate ligament (ACL) reconstruction with autologous ligament grafting at different time points.MethodsEighty‐five patients with ACL were categorized into two groups: Group A (GA, n = 45), who underwent early‐stage (≤3 weeks) surgery, and Group B (GB, n = 40), who underwent advanced‐stage (>3 weeks) surgery. Perioperative conditions, knee joint functions, activity and stability before and at 6 months postoperatively, changes in quality of life (QOL), good and excellent rates of knee joint functions, and incidence of complications were compared between the two groups.ResultsIn both groups, there was an increase in the International Knee Documentation Committee (IKDC) score, Lysholm score, and QOL and a decrease in the knee joint angle flexion limitation, angle of spread limitation, positive rates in the anterior drawer test (ADT), and Lachman test score (P < .05) after surgery. At 6 months postoperatively, the IKDC score, Lysholm score, and QOL were higher in GA than in GB (P < .05). The good and excellent rates of knee joint functions were higher in GA than in GB (93.33% vs. 77.50%) (P < .05).ConclusionAnterior cruciate ligament reconstruction with autologous ligament grafting can achieve good effects whether performed in the early or advanced stage; however, the improvements in patients'' knee joint functions and QOL are better in the early stage. Therefore, early ACL reconstruction with autologous ligament grafting is suggested.     

Patellafraktur nach MPFL-Plastik bei erhöhtem TTTG-Abstand

A 19-year-old patient suffered recurrent patellar dislocations and was treated by medial patellofemoral ligament (MPFL) reconstruction with a gracilis ligament autograft. Normal knee flexion while bowling led to a patella fracture 4 years after surgery. Further diagnostics showed a normal mechanical axis, no torsional deformity, no patellar or trochlear dysplasia and normal patella height. Source of the patellar instability was an increased tibial tuberosity-trochlea groove distance (19 mm). Surgical treatment was carried out with screw fixation of the patella fracture and tibial tuberosity transfer. The source of the patellar instability was not completely analyzed before surgery and ultimately led to a patellar fracture. A complete diagnostics of a patellar dislocation is always necessary before surgery.     

Phase Ib Trial of Mutant Herpes Simplex Virus G207 Inoculated Pre-and Post-tumor Resection for Recurrent GBM

We have previously demonstrated safety of G207, a doubly mutated (deletion of both γ₁34.5 loci, insertional inactivation of U_L39) herpes simplex virus (HSV) for patients stereotactically inoculated in enhancing portions of recurrent malignant gliomas. We have now determined safety of two inoculations of G207, before and after tumor resection. Inclusion criteria were histologically proven recurrent malignant glioma, Karnofsky score ≥70, and ability to resect the tumor without ventricular system breach. Patients received two doses of G207 totaling 1.15 × 10⁹ plaque-forming units with 13% of this total injected via a catheter placed stereotactically in the tumor. Two or five days later, tumor was resected en bloc with catheter in place. The balance of G207 dose was injected into brain surrounding the resection cavity. Six patients with recurrent glioblastoma multiforme were enrolled. Two days after the second G207 inoculation, one patient experienced transient fever, delirium, and hemiparesis, which entirely resolved on high-dose dexamethasone. No patient developed HSV encephalitis or required treatment with acyclovir. Radiographic and neuropathologic evidence suggestive of antitumor activity is reported. Evidence of viral replication was demonstrated. G207 appears safe for multiple dose delivery, including direct inoculation into the brain surrounding tumor resection cavity.     

MRI诊断女子排球运动员髌腱腱病

目的 探讨女子排球运动员髌腱腱病(PT)的MRI表现。方法 回顾性分析34名中国国家女子排球队运动员60个膝关节的MRI资料。结果 60个膝关节中,41个(26例)有PT(PT组),患病率76.47%,其中信号增强2级以上占82.93%(34/41)。13名19个膝关节阴性为对照组。PT组髌腱近端、中点、下止点前后径分别为(9.21±2.31)mm、(5.39±1.01)mm、(6.53±1.32)mm,与对照组相比差异有统计学意义(P<0.01)。PT组髌腱近端前后径与分级相关(r=0.334,P<0.01)。PT急性期髌腱近端增粗,T1WI低信号,T2WI中、高信号,FS-PDWI高信号;慢性期髌腱近端呈"V"形增粗增厚,T1WI低信号,T2WI中、低信号,FS-PDWI中等信号。髌腱近端后缘紊乱不清晰、髌腱中部和下止点信号增强以及髌骨下极增生等在两组间差异均有统计学意义(P<0.05)。所有患膝可见髌骨下极不规则片状、大小不一的信号增强。结论 女子排球运动员PT患病率较高。MRI有助于明确诊断、分期分级,鉴别髌骨下极损伤,监控康复效果以及评估运动能力。     

Particular tumor of the pancreas: A case report

BACKGROUNDGranular cell tumor (GCT) of the pancreas is a rare neurogenic tumor. The first case of pancreatic GCT was described in 1975, and up to now, only 7 cases have been reported.CASE SUMMARYA 53-year-old male had a pancreatic mass for 1 mo. He was not treated at the local hospital, but referred to Henan Tumor Hospital for surgery. Preoperative imaging revealed a 2.0 cm × 2.5 cm-sized mass located in the body of the pancreas. At the microscopic level, a large number of eosinophilic particles are present in the oval tumor cells. The immunohistochemistry of this tumor cell display CD56 (+), blood vessels CD34 (+), Ki-67 (+) < 10%, and S-100 (+).CONCLUSIONGCT of the pancreas should be recognized as a preoperative differential diagnosis of pancreatic tumors. Surgical resection of the tumor should be attempted; however, GCT of the pancreas has a certain rate of tumor metastasis and recurrence. Therefore, GCT of the pancreas requires regular and long-term follow-up.     

Uniportal video-assisted thoracoscopic surgery for complex mediastinal mature teratoma: A case report

BACKGROUNDMediastinal mature teratoma is the most common histological type of primary extragonadal germ cell tumor. In this report, we describe a rare case of giant mature teratoma located primarily in the anterior mediastinum and causing partial atelectasis of the upper and middle lobes of the right lung, as well as extrinsic compression of the right atrium.CASE SUMMARYA 31-year-old male with a giant mediastinal mature teratoma presented with progressive exertional dyspnea and chest pain for 1 mo. Computed tomography of the chest indicated the diagnosis of anterior mediastinal teratoma. The patient underwent right uniportal anterior approach video-assisted thoracoscopic surgery (VATS). En bloc resection of the giant teratoma, wedge resection of the upper and middle lobes of the right lung, resection of the thymus and partial excision of the pericardium were successfully performed. The pathological diagnosis revealed a mature cystic teratoma with foreign-body reaction that was closely related to the right lung, atrium dextrum, superior vena cava and ascending aorta. An atrophic thymic tissue was also discovered at the external teratoma surface. The patient was discharged on postoperative day 7.CONCLUSIONThis is the first report of the use of uniportal VATS for complete resection of a teratoma in combination with wedge resection of the right upper and middle lung lobes and partial resection of the pericardium.     

磁共振扩散张量成像诊断曲棍球运动员髌软骨早期损伤

目的 探讨应用磁共振扩散张量成像(DTI)诊断曲棍球运动员髌软骨早期损伤的可行性。方法 对40名非运动员(正常组)和17例专业曲棍球运动员(运动组)的双膝关节行质子密度加权成像(PDWI)和DTI扫描,生成DTI伪彩图,于连续两个髌软骨最大层面上选择5个ROI(内侧、偏内侧、中间、偏外侧、外侧),测量各ROI的各向异性分数(FA)和平均弥散系数(MD),并进行比较。结果 与正常组比较,运动组右侧髌软骨各部位的FA值减小,MD值增加,差异均有统计学意义(P均<0.001);左侧髌软骨上层偏外侧、外侧及下层偏外侧MD值增加,差异有统计学意义(P均<0.005)。运动组左、右髌软骨各部位的FA和MD值差异有统计学意义(P均<0.05)。运动组右侧髌软骨的上层内侧与外侧MD值的差异有统计学意义(F=7.02, P=0.012)。结论 FA值和MD值能够体现髌软骨水分子弥散能力的变化,量化髌软骨早期损伤的生化改变。DTI技术可以对曲棍球运动员髌软骨不同程度早期损伤的诊断提供影像学依据。