膝关节置换中以ROM技术定位胫骨假体的旋转力线

文题释义：ROM技术：其原理是先固定股骨假体,然后安放胫骨假体试模而不固定,使胫骨假体试件在股骨假体的引导下进行旋转位置的自我调整,达到胫骨平台自然的与股骨假体结合并处于最合适位置的目的,该技术是目前临床上定位胫骨假体旋转力线较为常用的方法,但据文献报道,该技术确定的胫骨假体旋转力线可能存在误差。 膝关节置换：经历了150年的演变史,目前已经成为晚期骨性关节炎患者的主要治疗措施｡根据膝关节置换部位可分为单间室置换(单髁置换)､双间室置换(膝关节内外间室)､髌股关节置换及三间室置换(内外间室及髌股间室)。国内运用最多的为膝关节双间室置换,常用的术式包括后交叉韧带替代型和后交叉韧带保留型双间室置换,多数文献认为选择哪一种手术方式对患者的长期疗效无显著差异。 背景：ROM技术是膝关节置换过程中确定胫骨假体旋转力线的常用方法,但该技术的准确性仍存在争议,目前ROM技术可能的影响因素尚未见报道。 目的：探讨膝关节置换过程中运用ROM技术确定胫骨假体旋转力线的影响因素。 方法：纳入61例初次接受单侧膝关节置换的患者,男18例,女43例,年龄55-78岁,术前均诊断为膝关节骨性关节炎,所有手术均采用后稳定型膝关节假体。所有患者对治疗方案均知情同意,且得到医院伦理委员会批准。根据ROM技术确定闭合与未闭合内侧支持带时胫骨假体旋转轴线,同时定位后交叉韧带止点中点与髌韧带内侧缘连线(Akagi线)作为参考线,测量2种情况下ROM技术确定的胫骨假体旋转轴线与Akagi线的相对位置关系,术中判断髌骨轨迹分型,从而确定髌骨轨迹分型及闭合内侧支持带与否是否为ROM技术的影响因素。 结果与结论：①术中出现Ⅰ,Ⅱ及Ⅲ型髌骨轨迹时,未闭合内侧支持带时ROM技术确定的胫骨假体旋转轴线与Akagi线之间的夹角分别为(0.5±2.5)°,(-0.9±2.6)°及(-3.9±3.4)°;闭合内侧支持带时夹角分别为(0.6±2.3)°,(-0.3±2.2)°及(-1.5±2.9)°;② Ⅲ型髌骨轨迹可导致ROM技术确定的胫骨旋转轴线与Akagi线之间的夹角明显偏内(P < 0.05);③对于Ⅰ,Ⅱ型髌骨轨迹,是否闭合内侧支持带对ROM技术确定的胫骨假体轴线无明显影响(P > 0.05);对于Ⅲ型髌骨轨迹,闭合内侧支持带可明显减小ROM技术确定的胫骨假体旋转轴线与Akagi线之间的差异(P < 0.05);④结果提示,ROM技术对Ⅰ,Ⅱ型髌骨轨迹的全膝关节置换能够较准确地定位胫骨假体的旋转轴线,无需闭合内侧支持带;出现Ⅲ型髌骨轨迹时,无论是否闭合内侧支持带都可能造成胫骨假体过度内旋。 ORCID: 0000-0002-7360-1881(李叶天) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

The role of the patellar tendon angle and patellar flexion angle in the interpretation of sagittal plane kinematics of the knee after knee arthroplasty: A modelling analysis

Background

Many different measures have been used to describe knee kinematics. This study investigated the changes of two measures, the patellar tendon angle and the patellar flexion angle, in response to variations in the geometry of the knee due to surgical technique or implant design.

Accuracy of patellar resection in total knee replacement. A study using the medial pivot knee

A series of 80 patellae were randomly allocated to osteotomy by sawing or milling while implanting the medial pivot knee. Three landmarks were used to control the plane of the cut in the coronal plane. The lateral edge of the patellar tendon distally, and both medial and lateral edges of the quadriceps tendon proximally. A line drawn across the widest points if the patella (the patellar horizon) was used to analyse the slope of the cut (P angle) and the orientation of the patella relative to the trochlear groove both pre- and post-operatively (PF angle) on 45 degrees skyline views. No patellae were under resected. The mean thickness of the remnant was 16 mm (range 14-19).There was no difference between sawing and milling, but the former was technically preferable. No patellae were found to be subluxed. The mean P angle was 2 degrees (S.D. 3.2). The maximum P angle was 10 degrees , but in no cases did obliquity of cut with under resection of the medial patellar facet lead to lateral tilt of the patellar horizon. The mean post-operative PF angle was 2.3 degrees (S.D. 2.6). The majority of patellae retained a similar orientation to the patellar groove post-operatively. In three patients, the patella tilted laterally with respect to the groove. One resulted from under resection of the lateral patellar facet and two in which the slope of the cut was good, probably resulted from an error in femoral rotation. In all 80 knees, the patellar dome remained in full contact with the groove. Use of three fixed landmarks provides consistent patellar resection in terms of depth and slope. Errors in slope of up to 10 degrees do not cause patellar tilt but may lead to medial overload due to increasing thickness of the patella. Errors in femoral sizing and rotation are more potent causes of lateral tilt and overload.     

Use of the Leeds-Keio prosthetic ligament for repair of patellar tendon rupture after total knee arthroplasty

We describe a technique for repair of the patellar tendon rupture after total knee arthroplasty (TKA), using the Leeds-Keio (L-K) prosthetic ligament. Two patients were followed for a mean of 38 months. Knee extension power and improved function were obtained in both cases. Use of the L-K ligament is a treatment option for repair of patellar tendon rupture following TKA.     

Total knee arthroplasty in a patellectomised posterior cruciate ligament-deficient knee: a new technique of patellar tendon bone grafting

Total knee arthroplasty in patients with previous patellectomy are less successful because of anteroposterior instability, residual pain and the loss of the mechanical advantage of the patella. To restore the moment arm of the quadriceps, the senior author (C.W.) described the technique of bone grafting the patellar tendon in a patient using the tibial plateau obtained from the routine tibial cut during total knee arthroplasty. The tibial eminence was used as the interfacetal ridge of the ‘created’ patella. At follow-up, the results were excellent with a postoperative knee society score of 90 and a postoperative patient functional score of 92. Radiological investigations showed a well-incorporated graft in the patellar tendon.     

Reconstruction of ruptured patellar tendon after total knee arthroplasty: a case report and a description of an alternative fixation method

Patellar tendon rupture after total knee arthroplasty is a rare, but often catastrophic complication. Many different reconstruction techniques of patellar tendon rupture have been described with variable and often discouraging results. A case report with patellar tendon rupture after a total knee arthroplasty is presented. Also, an alternative surgical technique of reconstruction of the patellar tendon using a semitendinosus-gracilis (STG) graft with an interference screw and a staple fixation enabling an immediate mobilization is described.     

Reconstruction of knee extensor with patellar tendon autograft following intraoperative radiotherapy

BackgroundPatellar tendon autograft after intraoperative extracorporeal radiotherapy has been used for reconstruction of the extensor mechanism following limb-sparing wide tumor resection around the knee. The purpose of this study was to determine the clinical outcome of this reconstruction technique.MethodsWe retrospectively reviewed six consecutive patients with peripatellar tendon and proximal tibial sarcoma who underwent reconstruction of the knee extensor mechanism. The resection area was planned to be contained with the patellar tendon in order to obtain a wide margin. First, the patella was osteotomized at the midline, and the inferior half of patella, patellar tendon, and tibial tuberosity were excised en bloc. The resected segments were devitalized with intraoperative extracorporeal radiotherapy and reimplanted into the original site. A follow-up evaluation included an assessment of the range of motion, extensor lag, the International Society of Limb Salvage score, and complications.ResultsSix patients were followed up for 121–270 months. One patient underwent an additional reconstruction with total knee arthroplasty due to a collapse of the tibial subchondral bone. A supracondylar fracture of the femur occurred in two patients, and a delayed union of the osteosynthesis site of the tibial shaft was observed in one patient. At the latest follow up, extensor lag had a median of five degrees, and International Society of Limb Salvage scores had a median of 83%. No local recurrence or rupture of the patellar tendon was observed.ConclusionsReconstruction of the knee extensor mechanism using a patellar tendon treated with intraoperative radiotherapy is a reliable and successful method.     

膝关节固定后髌骨腱的生物力学改变

背景：骨关节固定常作为防止受伤组织被再次损伤的方法。 目的：膝关节固定对兔髌骨腱力学特性及超微形态的影响。 方法：将20只成年兔等分为固定组和对照组。固定组兔左后肢通过石膏和2个可调铝夹板,保持膝伸直,踝关节屈曲90°,固定6周后,取髌骨腱-骨复合物,观察两组髌骨腱的生物力学性能和超微结构变化。 结果与结论：膝关节固定6周拉伸强度和切线模量分别下降至对照组的64.44%和53.08%(P < 0.01),但两组伸长率和最大负荷差异没有显著性意义。两组材料常数及应力应变关系曲线完全不同。固定组髌骨腱的横截面积明显大于对照组(P < 0.01),小胶原纤维占有优势。说明固定不仅会导致髌骨腱生物力学的变化,而且对髌骨腱自身也产生影响。     

Effects of patellar resurfacing on contact area and contact stress in total knee arthroplasty

The objective of this study was to examine the effects of patellar resurfacing on patellofemoral joint contact pressure and contact area in total knee arthroplasty. We tested seven fresh-frozen cadaveric knees using a custom knee jig which permits the simulation of physiologic quadriceps loading. Before patellar resurfacing, the mean peak contact pressure of medial and lateral patellofemoral joints was less than 10 MPa at knee flexion angles of 30 degrees, 60 degrees and 90 degrees, that of medial and lateral patellofemoral joints were 11.63 MPa and 11.42 MPa at a knee flexion angle of 120 degrees respectively, and the mean contact area of patellofemoral joint ranged from 70 to 150 mm2. After patellar resurfacing, the mean peak contact pressure of medial and lateral patellofemoral joints ranged from 50 to 100 Mpa (P<0.05), which exceeds the yield strength of ultrahigh molecular weight polyethylene, and the mean contact area of patellofemoral joint reduced to 10-15 mm2 (P<0.05). The contact pressure of patellofemoral joint was lower than the yield strength of articular cartilage before patellar resurfacing. Our results indicate that the yield stress of UHMWPE is exceeded after patellar resurfacing.     

Clinical outcome and patient satisfaction in aseptic and septic revision total knee arthroplasty

This study compares clinical outcome and patient satisfaction in 33 aseptic and 15 septic revision total knee arthroplasties across a 30-130-month follow-up. Aseptic revisions included only knees in which the femoral, tibial and patellar components had been exchanged, and excluded knees in which only isolated patellar components had been revised or only the tibial insert exchanged. Septic revisions included only knees in which there had been successful revision for chronic infection without recurrence of infection for at least 2 years from the index revision. The evaluation included pain scores, knee scores, functional scores, SF-12 functional surveys and radiographs of the knee. The results for the aseptic group were excellent in 26 (78.8%), good in 3 (9.0%), fair in 2 (6.1%) and poor in 2 (6.1%); those for the septic group were excellent in 5 (33.3%), good in 7 (46.7%), fair in 2 (13.3%) and poor in 1 (6.7%). The overall results of septic revision were less satisfactory than for aseptic revision. Aseptic revisions achieved significantly better knee scores and ranges of motion than septic revisions, but their pain and functional scores were similar. Despite the difference in knee scores, 85% of the patients from both groups were equally satisfied with the results of treatment. There was no discernible radiographic difference between the two groups, including radiolucency.     

Effective measurement of knee alignment using AP knee radiographs

The gold standard for measuring knee alignment is mechanical axis determined using full-limb radiographs (FLR). Measurement of joint alignment using antero-posterior (AP) knee radiographs is more accessible, economical and involves less radiation exposure to the patient compared with using full-limb radiographs. The aim of this study was to compare and assess the reproducibility of knee joint axial alignment on full-limb radiographs and conventional AP knee radiographs. Knee alignment was measured in 40 subjects (80 knees) from the TwinsUK registry. Measurement of mechanical knee alignment was from FLR, and anatomic knee alignment from weight-bearing AP knee radiographs. Reproducibility was assessed by intra-class correlation coefficients and kappa statistics. Reproducibility of knee alignment for both methods was good, with intra-observer ICC's of 0.99 for both FLR and AP radiographs. The mean alignment angle on FLR was 178.9 degrees (SD 2.1, range 173-183 degrees ), and 179.0 degrees (SD 2.1, range 173-185 degrees ) on AP films. 58.8% of knees on FLR and 66.3% on AP films were of varus alignment. Good correlations were seen between results for FLR and AP radiographs, with ICC ranging from 0.87-0.92 for left and right knees, and kappa statistics of 0.65-0.74. Standard AP knee radiographs can be used to measure knee alignment with good reproducibility, and provide comparable results to those obtained from FLR. This will facilitate measurement of knee alignment in existing cohort studies to assess malalignment as a risk factor of incident OA, and in clinical practice.     

The role of patellar tendon morphometry on anterior knee pain

Purpose  

To investigate the morphometry of patellar tendon with magnetic resonance imaging (MRI) and to reveal the relation between patellar tendon properties and anterior knee pain (AnKP).     

Arthroscopic-assisted anatomical reconstruction of the posterolateral corner of the knee joint

Several surgical techniques have been suggested to anatomically reconstruct the posterolateral corner of the knee joint. However, most of them are open techniques that require dissection of the skin and soft tissues without utilizing the advantages of arthroscopic-assisted techniques. Therefore, this study aimed to describe a novel arthroscopic technique that anatomically reconstructs the posterolateral corner of the knee joint. This novel arthroscopic technique can properly identify important landmarks for reconstruction and anatomically reconstruct the three key components (lateral collateral ligament, popliteus tendon, and popliteofibular ligament) of the posterolateral corner of the knee joint.     

Biomechanics of the knee joint in flexion under various quadriceps forces

Bioemchanics of the entire knee joint including tibiofemoral and patellofemoral joints were investigated at different flexion angles (0° to 90°) and quadriceps forces (3, 137, and 411 N). In particular, the effect of changes in location and magnitude of restraining force that counterbalances the isometric extensor moment on predictions was investigated. The model consisted of three bony structures and their articular cartilage layers, menisci, principal ligaments, patellar tendon, and quadriceps muscle. Quadriceps forces significantly increased the anterior cruciate ligament, patellar tendon, and contact forces/areas as well as the joint resistant moment. Joint flexion, however, substantially diminished them all with the exception of the patellofemoral contact force/area that markedly increased in flexion. When resisting extensor moment by a force applied on the tibia, the force in cruciate ligaments and tibial translation significantly altered as a function of magnitude and location of the restraining force. Quadriceps activation generated large ACL forces at full extension suggesting that post ACL reconstruction exercises should avoid large quadriceps exertions at near full extension angles. In isometric extension exercises against a force on the tibia, larger restraining force and its more proximal location to the joint substantially decreased forces in the anterior cruciate ligament at small flexion angles whereas they significantly increased forces in the posterior cruciate ligament at larger flexion angles.     

Bilateral dislocation of the knee with rupture of both patellar tendons. A case report

Knee dislocations are rare injuries caused by violent trauma. Damage to soft tissues and ligament lesions almost always accompany the injury. Vascular compromise further complicates the situation. We report a case of bilateral posterior knee dislocation with traumatic rupture of both patellar tendons. Treatment consisted of external fixation of both knees. Vascular compromise resolved with reduction and traction pins were placed on both patellae which were connected to the external fixators on following days. Primary repair of patellar tendon was undertaken after gradual distal repositioning of patella. The result is successful with full range of motion. Rupture of patellar tendon should be considered with posterior dislocation of the knee. External fixators provide quick stabilization in case of vascular compromise and can be modified to provide a traction system for distal repositioning of patella which allows primary repair of the patellar tendon.     

保留止点自体肌腱移植治疗陈旧性髌韧带断裂

背景：髌韧带在膝关节的运动中起着非常重要的的作用,因其断裂比较少见,临床上误诊率较高。目前重建髌韧带的方法较多,疗效报道不一,治疗不当容易出现髌骨位置不良,会严重影响膝关节的功能。 目的：探讨保留止点自体肌腱移植治疗陈旧性髌韧带断裂的临床疗效。 方法：对8例单侧陈旧性髌韧带断裂的患者行保留止点的半肌腱、股薄肌重建髌韧带,髌韧带重建后行半环形石膏后托固定屈膝15°1周,髌韧带重建后2周拆除切口缝线,3周去除石膏行股四头肌等长等张练习,6周时佩戴可调节膝关节护具进行膝关节活动度锻炼,3次/d,每周增加10°。髌韧带重建3个月后允许完全负重行走。 结果与结论：所有患者髌韧带重建后无并发症,X射线示髌骨恢复正常高度。膝关节功能恢复良好。所有患者髌韧带重建后24个月行走2 km以上膝关节无不适。与髌韧带重建前相比,髌韧带重建后24个月患者的Lysholm评分明显增加(P < 0.05),说明保留止点的半腱肌、股薄肌重建髌韧带可重建治疗陈旧性髌韧带断裂。     

A comparison of reproducibility of measurement techniques for patella position on axial radiographs after total knee arthroplasty

Patella position can be measured on axial radiographs and many measurement techniques have been described in literature. The goal of this study was to evaluate the inter- and intraobserver reproducibility of measurement techniques available in the literature for patients with a knee prosthesis. Fifty axial patella radiographs from knee prostheses were used to measure the reproducibility of five measurement techniques. Reproducibility was calculated using the Bland and Altman method. The Patellar Displacement (>or=4 mm) and the Lateral Patellar Tilt (>10 degrees) were found to be useful and clinically relevant. Based on our study we recommend that the most reproducible method to use for measurement of tilt, is Lateral Patellar Tilt; to measure displacement, the surgeon should use the Patellar Displacement technique.     

Patellar resurfacing has minimal impact on in vitro tibiofemoral kinematics during deep knee flexion in total knee arthroplasty

BackgroundWhile patellar resurfacing can affect patellofemoral kinematics, the effect on tibiofemoral kinematics is unknown. We hypothesized that patellar resurfacing would affect tibiofemoral kinematics during deep knee flexion due to biomechanical alteration of the extensor mechanism.MethodsWe performed cruciate-retaining TKA in fresh-frozen human cadaveric knees (N = 5) and recorded fluoroscopic kinematics during deep knee flexion before and after the patellar resurfacing. To simulate deep knee flexion, cadaver knees were tested on a dynamic, quadriceps-driven, closed-kinetic chain simulator based on the Oxford knee rig design under loads equivalent to stair climbing. To measure knee kinematics, a 2-dimensional to 3-dimensional fluoroscopic registration technique was used. Component rotation, varus-valgus angle, and anteroposterior translation of medial and lateral contact points of the femoral component relative to the tibial component were calculated over the range of flexion.ResultsThere were no significant differences in femoral component external rotation (before patellar resurfacing: 6.6 ± 2.3°, after patellar resurfacing: 7.2 ± 1.8°, p = 0.36), and less than 1° difference in femorotibial varus-valgus angle between patellar resurfacing and non-resurfacing (p = 0.01). For both conditions, the medial and lateral femorotibial contact points moved posteriorly from 0° to 30° of flexion, but not beyond 30° of flexion. At 10° of flexion, after patellar resurfacing, the medial contact point was more anteriorly located than before patellar resurfacing.ConclusionDespite the potential for alteration of the knee extensor biomechanics, patellar resurfacing had minimal effect on tibiofemoral kinematics. Patellar resurfacing, if performed adequately, is unlikely to affect postoperative knee function.     

Patellar tracking after total knee arthroplasty performed without lateral release

There is limited clinical data on patellar maltracking in patients who have undergone total knee arthroplasty (TKA) without lateral release. We performed a retrospective review of 191 consecutive TKAs performed by one surgeon through the subvastus approach without lateral release from 2007 to 2008. Radiographic measurements were made using the preoperative and postoperative 2 years radiographs. Multivariate logistic regression analysis was performed to determine the risk factors for patellar maltracking after TKA performed without lateral release. TKA resulted in increases in the patellar tilt and displacement (P<0.05). The presence of preoperative patellar tilt and displacement were predictive of postoperative patellar tilt and displacement in patients who underwent TKA through the subvastus approach without lateral release (P<0.05).     

Moment arms of the knee extensor mechanism in children and adults

In the present study we investigated whether there are differences in the patellar tendon moment arm (PTMA)-knee angle relationship between pre-pubertal children and adults, and whether the PTMA length scales to relevant anthropometric measurements in the two groups. Anthropometric characteristics and the PTMA length-joint angle relationships were determined in 20 adults and 20 pre-pubertal children of both genders. The anthropometric characteristics measured were height, body mass, knee circumference, medio-lateral knee breadth, anterior-posterior knee depth, leg length, femur length and tibia length. The PTMA was quantified from magnetic resonance images using the geometric centre of the femoral condyle method, at every 5° between 55° and 90° of knee flexion (0° is full extension). Adults had a significantly greater PTMA length at all joint angles (4.2 ± 0.4 vs. 3.6 ± 0.3 cm at 90°; P  < 0.01), with the PTMA length decreasing from knee extension to knee flexion similarly in both adults and children. There were no significant and strong correlations between the PTMA and anthropometric measures in adults for any joint angle. In contrast, the PTMA correlated and scaled with anthropometric characteristics for the children ( P  < 0.05, r  = 0.49–0.9) at all joint angles. The PTMA length in children was most accurately predicted at 85° of flexion from the equation PTMA = –0.25 + 0.083·tibia length + 0.02·leg length ( R ² = 0.83). These findings indicate that the knee extensor mechanism in pre-pubertal children should not be considered to be a 'scaled-down' version of that in adults.