Midterm comparison of posterior cruciate-retaining versus -substituting total knee arthroplasty using the Genesis II prosthesis. A multicenter prospective randomized clinical trial

The purpose of the current study was to compare midterm outcomes of posterior cruciate-retaining (CR) versus posterior cruciate-substituting (PS) procedures using the Genesis II total knee arthroplasty (TKA) system (Smith and Nephew, Memphis, TN). Ninety-nine (99) CR and 93 PS TKA's were analyzed in this prospective, randomized clinical trial. Surgeries were performed at seven medical centers by participating surgeons. Clinical outcomes (Knee Society Score, Range of Motion, WOMAC, SF-12, and Radiographic Findings), in addition to postoperative complications, were evaluated with a minimum follow-up of 5 years. Following data analysis, there were no significant differences in patient demographics or preoperative clinical measures between the two groups. At the latest follow-up interval, no significant differences were found between the CR and PS groups with regards to functional assessment, patient satisfaction, or postoperative complication. However, the PS group did display statistically significant improvements in range of motion when compared with the CR group. The results of this investigation would suggest that, while comparable in regards to supporting good clinical outcomes, the PS Genesis II design does appear to support significantly improved postoperative range of motion when compared with the CR design.     

后交叉韧带保留型和后稳定型全膝关节假体置换后早期关节遗忘度的对比

背景:临床长期随访显示,后交叉韧带保留型与后稳定型假体置换后的膝关节活动度、10-15年假体生存率及主要临床表现等方面无明显区别,但针对两种膝关节假体孰优孰劣的争论依然存在。目的:对比后叉韧带保留型和后稳定型假体置换治疗单侧膝关节骨关节炎术后患者早期功能恢复的差别。方法:选择2018年7月至2019年9月安徽医科大学第一附属医院收治的60例膝关节骨关节炎患者,其中男13例,女47例,年龄46-83岁,其中30例接受后叉韧带保留型假体置换治疗,另30例接受后稳定型假体置换治疗。术后3个月及末次随访时,进行关节遗忘评分、膝关节功能HSS评分、目测类比评分与膝关节活动度评价。研究获得安徽医科大学第一附属医院伦理委员会批准。结果与结论:①60例患者获得5-16个月随访,随访期内均未出现假体周围感染、松动、脱位及僵硬等并发症;②术后3个月及末次随访时,两组间关节遗忘评分、膝关节功能HSS评分、目测类比评分与膝关节活动度比较差异均无显著性意义(P>0.05);③结果表明,后叉韧带保留型和后稳定型假体置换治疗单侧膝关节骨关节炎术后患者早期关节遗忘度无差别。     

Prospective sequential comparison of femoral roll-back between cruciate-retaining and posterior-stabilized total knee arthroplasty using an intra-operative sensor

BackgroundImplant design and surgical techniques affect postoperative knee kinematics in total knee arthroplasty (TKA). This study aimed to compare femoral roll-back between cruciate-retaining (CR) and posterior-stabilized (PS) TKA in the same knee by objectively quantifying the contact point kinematics of the tibiofemoral joint using a sensor.MethodsIn the present prospective study, we used an intraoperative sensor to compare medial and lateral roll-back during 0-120° knee flexion in 33 knees that underwent CR and PS TKA. We also examined the relationship between mediolateral balance and the lateral-to-medial roll-back ratio. We defined the contact percentage position as the vertical length to the contact point divided by the anteroposterior length of the tibial plate.ResultsThe roll-back percentage following PS TKA (19.8 ± 5.1%) was significantly higher than that after CR TKA in both the medial (19.8 ± 5.1% versus 7.1 ± 2.5%, P < 0.001) and lateral (26.8% ± 3.8% versus 18.7 ± 3.8%, P < 0.001) compartments. The medial contact pressure at 90° was significantly correlated with the increased lateral-to-medial roll-back ratio in both CR and PS TKA (both P < 0.001).ConclusionPS TKA resulted in a higher percentage of femoral roll-back in the medial and lateral compartments than CR TKA. CR TKA caused a higher lateral-to-medial roll-back ratio compared to PS TKA. To reproduce medial pivot knee motion similar to that of a normal knee, the medial soft tissue needed to be balanced more tightly than the lateral soft tissue during TKA. These findings provide some clinical evidence of TKA design selection and proper mediolateral balancing for successful TKA.     

Comparison of the biomechanical effect of posterior condylar offset and kinematics between posterior cruciate-retaining and posterior-stabilized total knee arthroplasty

Background

The effect of the changes in the femoral posterior condylar offset (PCO) on anterior–posterior (AP) translation and internal–external (IE) rotation in cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) remains unknown. The purpose of this study was to compare the kinematics in CR and PS TKA with respect to the difference in prosthetic design and PCO change through a computational simulation.

全膝关节置换术中度屈曲不稳定的影响因素

随着人口老龄化的到来,全膝关节置换例数逐年上升。目前两种学派使用的假体后交叉保留型(CR)和后方稳定型(PS),国内学者更倾向于PS。近年来翻修病例越来越多,不稳定逐步取代感染成为早期翻修的主要原因。中度屈曲的稳定性对于行走功能非常重要,因此得到业内广泛关注。现在任何一种假体和手术技术都无法彻底解决中度屈曲不稳。本文分析了CR和PS术后中度屈曲稳定性的差异,旨在给关节科同道提供理论依据和发展方向。     

Spontaneous dislocation of a mobile-bearing polyethylene insert after posterior-stabilized rotating platform total knee arthroplasty: a case report

We describe a dislocation after Scorpio mobile-bearing total knee arthroplasty. This system is a rotating platform posterior-stabilized design and utilizes a single post as part of the metal tibial tray. Only one locking ring inside the socket of the polyethylene insert secures a tight connection with the post. Spontaneous dislocation between the polyethylene insert and the metal tray occurred at 22 months post surgery while rising from the supine position with slight knee flexion. Operative findings revealed failure of the locking ring and the original insert was replaced with a thicker insert. Our case and a duplicated saw bone model demonstrated that failure of the locking system resulted in the dislocation of the insert.     

Intraoperative kinematics of bicruciate-stabilized total knee arthroplasty during high-flexion motion of the knee

BackgroundIt is unknown whether intraoperative kinematics of bicruciate-stabilized total knee arthroplasty (BCS-TKA) are different for different activities. It has also not been established whether intraoperative high-flexion motions correlate with postoperative patient-reported outcome measures (PROMs). We aimed to clarify the intraoperative kinematics of BCS-TKA during high-flexion activities and describe the relationship between intraoperative and postoperative patient-reported outcomes.MethodsWe examined 33 knees from 31 patients who underwent BCS-TKA and measured intraoperative knee kinematics, passive knee flexion, and cross-legged flexion using a navigation system. We also calculated knee flexion, varus-valgus, and rotation angles. As a secondary evaluation, we divided the patients into two clusters based on the PROMs and compared the kinematics between them.ResultsThe valgus moved by 1.3 ± 1.3° beyond 90° knee flexion during passive flexion. In contrast, during cross-legged flexion, the varus moved by 4.6 ± 5.1° beyond 30° flexion. This indicated significantly increased varus alignment in the cross-legged flexion as compared with passive flexion. Beyond 60° of flexion, the femur displayed 8.8 ± 4.8° of external rotation relative to the tibia. In cross-legged flexion, the femur displayed 9.2 ± 6.5° of external rotation relative to the tibia beyond 45° of flexion. At 90° of flexion, the cross-legged knees rotated more externally. There were no significant postoperative differences between the high- and low-score clusters.ConclusionThe intraoperative knee kinematics after BCS-TKA during high-flexion motions differed depending on the performance of an individual. This will be useful for physicians who might recommend BCS-TKA to new patients.     

Short-term functional advantages after medial unicompartmental versus total knee arthroplasty

Background

There are many uncertainties about the advantages and disadvantages of using unicompartmental (UKA) versus total knee arthroplasty (TKA) to treat patients with knee osteoarthritis. It is important to have sufficient early postoperative quadriceps strength for long-term, self-reported and gait-related outcomes after knee arthroplasty, but very limited comparative data exist regarding UKA and TKA patients.

Clinical efficacy and cost-effectiveness of postoperative radiographs after total knee arthroplasty

BackgroundPostoperative radiographs are commonly ordered after primary total knee arthroplasty (TKA), however, there is limited data on how often these films change management over the entire postoperative time course, and what should prompt imaging to maximize clinical utility.MethodsA retrospective cohort study was conducted of patients ≥ 18 years old who underwent a primary TKA at two level one trauma centers. Postoperative data were collected to determine the frequency of postoperative radiograph series, radiograph findings that did not suggest normal healing or alignment to radiologist and orthopedists, and changes in postoperative management. The total cost and radiation exposure values were calculated for all patient radiographs using estimates from previous literature.ResultsFrom the 1258 patients included, 3831 postoperative radiographs were taken (mean ± 95% confidence interval [CI]: 3.05 ± 0.11 radiographs per patient). Of these 3831 radiographs, 44 (1.1%) contained a positive radiographic finding. Only 13 (0.3% of radiographs) of these positive radiographic findings were positive orthopaedic findings, 11 of which led to changes in management. For all but 1 of these patients (10/11, 91%), these radiographs were taken during a non-routine postoperative visit. Routine postoperative radiographs that did not change management cost $1,008,480 and administered 22.92 mSV of radiation to patients within this study.ConclusionPostoperative radiography obtained after primary TKA were of low clinical utility yet resulted in considerable healthcare costs and unnecessary radiation burden. Radiographs ordered during a non-routine visit, however, were a reliable indicator of when this imaging provided clinical utility.     

Recurrent dissociation of the tibial insert after mini-subvastus posterior-stabilized total knee arthroplasty: A case report

We report here on an unusual case of recurrent dissociation of a polyethylene tibial insert from its metal baseplate after high-flex posterior-stabilized (PS) Genesis II total knee arthroplasty with using the mini-subvastus approach. After the 1st episode of dissociation, which had happened 1 month after the primary surgery, we changed the tibial insert and found damages on the dovetails and the post of the retrieved insert. Unfortunately, the patient suffered the same dissociation 1 month after the tibial insert was changed. This case illustrates that incomplete seating of the insert due to limited surgical exposure and anterior impingement of the high-flex PS post may contribute to the risk of dissociation.     

初次全膝关节置换后弹力绷带的应用

文题释义：全膝关节置换：是目前治疗晚期原发性骨关节炎或者类风湿性膝关节炎的有效手段。它主要是通过外科手术将膝关节假体置入患者体内,代替原本生理结构,从而达到消除疼痛、恢复力线以及改善功能的目的。 弹力绷带：一般由自然纤维编织而成,治疗柔软,通常用于外科包扎护理。因其具有弹性高、透气性好、不会限制和影响活动、不会妨碍血液循环等独特优势,非常适合应用于关节部位的加压包扎。 背景：全膝关节置换后常规使用弹力绷带到底会不会使患者受益,目前仍缺乏足够的临床证据。 目的：探讨在初次全膝关节置换后使用弹力绑带是否对患者的预后有益。 方法：选择2017年9月至2018年9月因膝关节骨关节炎在青岛大学附属医院西海岸院区关节外科接受初次同期双侧全膝关节置换的60例患者,随机选择一侧肢体使用普通外科敷料的同时使用从脚背到大腿中部的弹力绷带加压包扎(弹力绷带组),一侧肢体只使用普通外科敷料(对照组)。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。由不参与患者管理的专业人员,在术后1,2,3和7 d分别测量患者双下肢(大腿、膝关节和小腿处)的周径、伸屈活动度以及静息、运动疼痛目测类比评分,记录术后24 h引流管引流量以及术后30 d内并发症发生情况。 结果与结论：①术后第1,2,3,7天,弹力绷带组大腿、膝关节以及小腿周径均小于对照组,膝关节活动度优于对照组,差异有显著性意义(P < 0.001);②术后第1,2天,弹力绷带组静息目测类比评分高于对照组(P < 0.001),但是术后第7天低于对照组(P < 0.001),在术后第3天,2组间差异无显著性意义;弹力绷带组运动目测类比评分在术后第1,2天要大于对照组(P < 0.001),但在术后第3,7天时2组差异无显著性意义;③2组间在伤口愈合并发症方面没有差异,但样本量过小,无法用有意义的统计学方法进行分析;④2组间在术后24 h时引流管引流量差异比较有显著性意义;⑤随访30 d内均未出现深部感染、静脉血栓以及再手术情况;⑥提示在初次膝关节置换术后应用从脚背到大腿中部的弹力绷带能有效减轻术肢肿胀及术后失血量,增加术肢的屈伸活动,有利于术后快速康复,值得推广应用。 ORCID: 0000-0001-6675-8904(张成龙) 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     

Early comparative outcomes of unicompartmental and total knee arthroplasty in severely obese patients

Background

Medial unicompartmental knee arthroplasty (UKA) may have advantages over total knee arthroplasty (TKA) in the setting of obesity. There has been no direct comparison between the two cohorts. This study compares outcomes and complications of severely obese patients undergoing medial UKA versus TKA.

Gait and functional status analysis before and after total knee arthroplasty

Background

Among the procedures for severe gonarthrosis, total knee arthroplasty (TKA) is considered a successful method patient satisfaction and functional improvement; however, TKA is commonly associated with incompletely recovered gait function. The aim of this study was to evaluate the influence of TKA and physiotherapy programmes on gait features and patient-reported functional status and the relationship between them, leading to broader knowledge of the origins of long-term gait disturbances.

Long-term survivorship of total knee arthroplasty with a single-radius,high-flexion posterior stabilized prosthesis

BackgroundThe purpose of this study was to determine functional outcomes, implant survival rate, and complications of a single-radius, high-flexion posterior stabilized (PS) total knee prosthesis at a minimum follow up of 10 years for a consecutive series.MethodsThis retrospective observational study included 395 consecutive patients who underwent 585 single-radius, PS total knee arthroplasties (TKAs) between January 2009 and December 2009. Their functional outcomes, implant survival rates, radiological findings, and complications were evaluated.ResultsAt a mean follow up of 11.2 years (range, 10.6–11.8 years), 395 (80.8%) patients were available for review. At final follow up, preoperative Knee Society knee scores were improved from 37.3 to 80.1 (P < 0.05) and function scores were improved from 35.7 to 80.5 points (P < 0.05). Sixteen knees (2.7%) in 15 patients required revision surgery due to 11 septic loosening (1.9%) and five aseptic loosening events (0.8%). Cumulative survival for the prosthesis was 97.3% for any cause at 10 years. A total of 34 radiolucent lines (5.8%) were detected an average of 2.4 years following surgery and radiological assessment did not reveal any evidence of component migration at final follow up.ConclusionsSingle-radius, high-flexion PS TKA showed good long-term survival rates and clinical outcomes. Further study is required to determine whether limited radiolucency findings at the tibial component–tibial plateau could progress to or result in the loosening of components.     

Evaluation of anteroposterior accelerometric change after bi-cruciate stabilized total knee arthroplasty and posterior stabilized total knee arthroplasty

BackgroundIn conventional total knee arthroplasty (TKA), the anterior cruciate ligament (ACL) is resected. ACL dysfunction causes knee instability and is regarded as one factor in poor TKA outcomes. In bi-cruciate stabilized (BCS) TKA, the implant reproduces ACL function and provides anterior stability. The objective of this study was to evaluate preoperative and postoperative X-rays and accelerometer gait measurements in patients who underwent BCS TKA and posterior-stabilized (PS) TKA to assess the postoperative acceleration changes of knees after these procedures and to compare them in terms of joint range of motion (ROM) and the New Knee Society Score (New KSS).MethodsThe subjects were 60 patients, 30 of whom underwent BCS TKA and 30 PS TKA. Joint ROM, New KSS, lateral X-rays of the standing extended knee, and accelerometer data were evaluated 12 months postoperatively.ResultsThere was no significant difference in joint ROM between the groups. Both had good New KSS results, but the functional activity score was significantly higher after BCS TKA than after PS TKA. X-rays showed a lower posterior offset ratio after BCS TKA than after PS TKA, with anteroposterior positioning closer to that of the normal knee.Accelerometer data showed that postoperative anteroposterior acceleration on the femoral side in the stance phase and swing phase was lower after BCS TKA than after PS TKA.ConclusionCompared with PS TKA, BCS TKA resulted in a higher functional activity score, closer positioning to that of the normal knee on lateral X-ray, and lower anteroposterior acceleration on the femoral side.     

前稳定型垫片在全膝关节置换术中的早期临床研究

目的探讨全膝关节置换术(TKA)中应用前稳定型(AS)垫片的临床效果。方法 2018年1月至2018年12月选取北京大学人民医院收治的107例终末期骨性关节炎行全膝关节置换患者,术中采用邦美公司提供的后交叉韧带保留型(CR)Vanguard膝关节假体,其中使用AS垫片组45例,CR垫片组62例。统计全部患者的手术时间,术后伤口引流量,感染并发症,术前、术后膝关节活动度和膝关节协会评分,比较AS垫片组和CR垫片组之间的差异。结果全部病例均获得随访,随访时间为12~24个月,平均(20.3±2.8)个月。术前AS垫片组、CR垫片组膝关节活动度分别为平均90.2°±17.4°、92.7°±18.6°,术后末次随访时AS垫片组、CR垫片组分别为平均108.5°±22.3°、110.6°±19.3°。膝关节协会评分术前AS垫片组为临床评分(50±15)分、功能评分(52±21)分,CR垫片组为临床评分(49±13)分,功能评分(52±19)分;术后末次随访时AS垫片组临床评分(80±16)分、功能评分(82±20)分;CR垫片组临床评分(82±15)分、功能评分(83±22)分。上述各评价指标、手术时间、术后伤口引流量两组间差异均无统计学意义。所有病例均未出现感染并发症。结论 TKA术中应用AS垫片术后早期膝关节活动度、膝关节协会评分结果良好,与CR垫片相比较效果相当。     

Translational and rotational knee joint stability in anterior and posterior cruciate-retaining knee arthroplasty

This study investigated passive translational and rotational stability properties of the intact knee joint, after bicruciate-retaining bi-compartmental knee arthroplasty (BKA) and after posterior cruciate retaining total knee arthroplasty (TKA). Fourteen human cadaveric knee specimens were used in this study, and a robotic manipulator with six-axis force/torque sensor was used to test the joint laxity in anterior–posterior translation, valgus–varus, and internal–external rotation. The results show the knee joint stability after bicruciate-retaining BKA is similar to that of the native knee. On the other hand, the PCL-retaining TKA results in inferior joint stability in valgus, varus, external rotation, anterior and, surprisingly, posterior directions. Our findings suggest that, provided functional ligamentous structures, bicruciate-retaining BKA is a biomechanically attractive treatment for joint degenerative disease.     

Angiosarcoma after revision total knee arthroplasty

BackgroundHemarthrosis after total knee arthroplasty (TKA) is a relatively rare complication. Although most cases are effectively treated with conservative therapy, some cases require angiographic embolization or surgical intervention. Angiosarcoma is a rare malignant tumor derived from the vascular endothelium with neovascular hyperplasia and mainly arises in the skin and superficial soft tissue, and less frequently in deep soft tissue and bone. Although malignant neoplasms such as angiosarcoma in the vicinity of orthopedic implants were reported, the causal relationship between development of the malignant tumor and the orthopedic implant is widely debated in the literature.Case presentationWe report the case of a 68-year-old female with angiosarcoma that developed in the knee joint 2 years after revision TKA. The patient exhibited severe persistent bleeding, which reached 1000–1400 ml per day for 4 months. Histological analysis of the synovial tissue in the knee joint showed large cells with nuclear atypia. Immunohistochemical staining showed cells that were positive for CD31, CD34, and D2-40, and she was diagnosed with angiosarcoma. The patient underwent an amputation at the level of the thigh, and her general condition immediately improved after the operation. The patient did not exhibit bleeding from the site of amputation, and no local recurrence or distant metastases were detected 1 year after the amputation.ConclusionsTo the best of our knowledge, this represents the first report of angiosarcoma 2 years after revision TKA. Further careful follow up is needed, given the high-grade malignancy.     

Radiographic severity,extent and pattern of cartilage loss are not associated with patient reported outcomes before or after total knee arthroplasty in end-stage knee osteoarthritis

BackgroundThe aim of this study was to determine if radiographic severity, extent or pattern of knee osteoarthritis was associated with pain and function before total knee arthroplasty (TKA) or improvement therein one year after TKA.MethodsA prospective study of 259 patients undergoing unilateral TKA for Kellgren-Lawrence (KL) grade ≥ 3 knee osteoarthritis was conducted: mean age 69.8 ± 9.7 (44–91); mean BMI 31.0 ± 5.8 (17–52); 152/259 (58.7%) female. Preoperative radiographs were assessed using the KL and Ahlback systems. Preoperatively and 1 year postoperatively patients completed Oxford Knee Scores, VAS-Pain and EQ-5D scores. Full thickness cartilage loss was recorded intraoperatively.ResultsMedian radiographic severity was Ahlback 2, KL 4: 51/259 (19.7%) hypertrophic; 23/259 (8.8%) atrophic. Neither Ahlback nor Kellgren-Lawrence OA grade was associated with OKS, VAS Pain or EQ-5D prior to TKA (p > 0.05). The extent and pattern of cartilage loss did not affect preoperative PROMs. Radiographic OA severity, compartment involvement, and pattern of cartilage loss were not significantly associated with PROMs or improvements therein following TKA (p > 0.05). Hypertrophic OA was associated with less pain before TKA (difference 6.8, 0.23–13.9 95%CI, p = 0.044), and worse improvement in OKS following TKA (difference −3.41, −6.8 to −0.05 95%CI, p = 0.047). Better preoperative OKS and hypertrophic OA were independently associated with poorer improvement in OKS 1 year following TKA (R² = 0.208).ConclusionProvided at least one compartment has KL grade ≥ 3 changes, further radiographic severity, pattern or extent of cartilage loss did not affect PROMs before or after TKA: multicompartmental was no worse than unicompartmental disease.     

In vivo kinematics of a newly updated posterior-stabilised mobile-bearing total knee arthroplasty in weight-bearing and non-weight-bearing high-flexion activities

BackgroundThe purpose of this study was to clarify the in vivo kinematics of a newly updated posterior-stabilised (PS) mobile-bearing total knee arthroplasty during high-flexion activities in weight-bearing (WB) and non-weight-bearing (NWB) conditions. The hypothesis was that the kinematics would differ between the WB and NWB conditions, and the kinematics would be affected by the WB condition.MethodsThe kinematics of 19 knees were investigated under fluoroscopy during squatting (WB) and active-assisted knee flexion (NWB) with two- and three-dimensional registration technique. Accordingly, the range of motion, anteroposterior (AP) translation of the medial and lateral contact points, axial rotation of the femoral component relative to the tibial component, and kinematic pathway were evaluated.ResultsThere was no difference in the knee’s range of motion between the WB and NWB conditions. The medial AP translation of the femur did not differ in each flexion angle between WB and NWB conditions except for flexions of 70°. There was no difference in the lateral AP translation of the femur at all tested flexion angles between the WB and NWB conditions. The external femoral rotation and the medial pivot motion were observed throughout all flexion angles in WB conditions. The clinical relevance is that this implant could produce ideal medial AP stability and medial pivot motion.ConclusionThe medial AP translation of the femur was stable for AP direction when it was in both WB and NWB conditions. In WB conditions, the medial pivot motion was observed throughout all flexion angles.Level of Evidence: III.