Regional bone density changes in anterior cruciate ligament deficient knees: a DEXA study

Bone mineral density (BMD) loss is one of the secondary problems occurring in knee joint after injury of anterior cruciate ligament (ACL). The effect of this injury on BMDs of specific regions is not clear. The aim of this study was to investigate BMD changes in unreconstructed ACL-deficient knees with subregion analysis of dual energy X-ray absorptiometry (DEXA). Precision and reliability studies of DEXA revealed that two region of interests (ROI) in medial condyle, two ROIs in lateral femoral condyle (LFC) and one ROI in medial tibial plateau (MTP) in anteroposterior (AP) DXA view and one ROI for each of distal femur, proximal tibia and patella in lateral view had high reproducibility and reliability. Thirty-two patients with complete ACL ruptures were collected for the study and uninjured sides served as the control. All the patients were male with a mean age of 30 years. Mean duration of ACL rupture was 24 months. There were significant BMD losses in both ROIs of LFC and ROI of MTP in AP view and all three ROIs of lateral view. Greatest BMD losses in AP and lateral views were at MTP and patella respectively. There was a significant association between patellar BMD loss and duration after trauma. Bone bruises in lateral condyle might be the cause of selective involvement of LFC. Periarticular bone mineral loss in ACL-deficient knees has a predilection for the specified region of interest rather than uniform periarticular loss. This may be important for graft fixation or a factor in tunnel enlargement.     

活动与固定平台单髁置换治疗膝关节内侧单间室骨关节炎的随访

文题释义：单髁假体置换：为人工膝关节置换的一个特殊类型,是一种置换范围局限在单侧髁的置换。膝单髁关节置换与全膝关节置换几乎同时起步于20世纪70年代初期,单髁关节置换的目的是尽可能地保留正常的关节结构,以期获得更好的功能恢复,目前临床上单髁假体有活动平台和固定平台两种单髁假体。下肢机械轴位置Kennedy和White分布：把胫骨平台分为0、1、2、C、3、4、5几个区域,观察股骨头中心—踝关节中心连线经过胫骨平台的区域。KENNEDY和WHITE的研究发现,单髁置换后下肢机械轴经过2、C区的术后效果好,并发症少。背景：单髁置换假体主要分为活动平台和固定平台2种类型,由于两种平台假体的设计理念和手术操作方法上的不同,对于两种平台假体的选择还有一定分歧和争议。 目的：比较活动与固定平台单髁假体置换治疗膝关节内侧间室骨性关节炎的临床效果。 方法：选择2014年2月至2015年2月佛山市中医院收治的单侧膝关节内侧间室骨关节炎患者154例,男54例,女100例,年龄56-81岁,其中100例接受活动平台单髁假体置换治疗(活动平台组),54例接受固定平台单髁假体置换治疗(固定平台组)。记录并发症发生情况。术后随访膝关节目测类比评分、膝关节活动度、膝关节功能与临床KSS评分,复查X射线片(胫股角、髋-膝-踝角度、胫骨后倾角)评估下肢力线矫正情况。研究符合佛山市中医院对研究的相关伦理要求(fsz20130642)。结果与结论：①154例患者术后获得60-72个月的随访;②两组末次随访的膝关节目测类比评分、膝关节活动度、膝关节功能与临床KSS评分均较术前明显改善(P < 0.05),两组间比较差异无显著性意义(P > 0.05);③两组末次随访的胫股角、髋-膝-踝角度、胫骨后倾角均较术前明显改善(P < 0.05),活动平台组胫股角与髋-膝-踝角度的矫正值大于固定平台组(P < 0.05),两组间胫骨后倾角矫正值比较差异无显著性意义(P > 0.05);两组间下肢机械轴位置Kennedy和White分布比较差异无显著性意义(P > 0.05);④活动平台组出现1例假体松动,2例衬垫脱位;⑤结果表明,两种平台单髁置换假体治疗膝关节内侧间室骨性关节炎的中期随访临床结果无明显差异,但活动平台单髁假体置换下肢力线矫正角度较固定平台大,对于恢复下肢解剖轴线更有优势;2种单髁假体术后并发症发生率均较低,活动平台单髁置换后中期随访并发症发生率高于固定平台,活动平台中期并发症主要是假体松动、衬垫脱位。ORCID: 0000-0001-9062-8026(刘少华) 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     

内侧胫骨平台倾斜角与前交叉韧带损伤相关性的Meta分析

背景：内侧胫骨平台倾斜角作为前交叉韧带损伤的一项解剖学相关危险因素,一直受到研究者的重视,但其相关性的存在与否,各项研究的结果不尽相同。 目的：分析内侧胫骨平台倾斜角与前交叉韧带损伤的相关性,并探讨其是否存在性别特异性。 方法：计算机检索cochrane图书馆、MEDLINE数据库、Elsevier数据库、中国生物医学文献数据库、万方数据库以及手工检索相关文献的参考文献。所有检索截止至2011-11-01。收集国内外公开发表的有关内侧胫骨平台倾斜角与前交叉韧带损伤相关性的病例对照研究和横断面研究文献,采用STATA 11.0统计软件进行统计分析。 结果与结论：纳入Meta分析的文献共12篇,累计研究对象1 823例,损伤组888例,对照组925例。纳入研究表明,损伤组与对照组内侧胫骨平台倾斜角的合并加权均值差为1.06,95%CI(0.36,1.76),P < 0.05;亚组分析结果表明,男性病例中损伤组与对照组内侧胫骨平台倾斜角的合并加权均值差为0.84,95%CI(-0.03,1.70),P > 0.05,女性病例中损伤组与对照组内侧胫骨平台倾斜角的合并加权均值差(WMD)为1.62,95%CI(0.72,2.52),P < 0.05。提     

单髁置换术应用于骨关节炎合并前交叉韧带缺失的三维有限元研究

目的采用有限元方法比较前交叉韧带(anterior cruciate ligament,ACL)完整与缺失的骨关节炎患者单髁关节置换(unicompartmental knee arthroplasty,UKA)术后膝关节生物力学特性,分析ACL缺失对膝关节单髁置换术后的运动和应力的影响。方法根据膝关节CT、MRI图像,建立有限元模型。采用逆向工程技术重建活动衬垫单髁假体,加载入该正常膝关节三维有限元模型。在不同屈膝角度(0°、30°、60°、90°、120°)加载载荷,观察在ACL完整(ACL-intact,ACLI)和缺失(ACL-deficiency,ACLD)情况下,膝关节的最大接触压和位移程度。结果 UKA-ACLI与UKA-ACLD模型在膝关节屈膝各角度,各部位(外侧股骨软骨、胫骨软骨、半月板、股骨假体、胫骨假体、衬垫)最大应力无明显差异,ACLD模型在膝关节屈膝0°和30°位前后位移明显大于ACLI模型,在膝关节屈膝0°位股骨相对内旋减小,在膝关节屈膝30°位股骨相对外旋增加。结论标准位置假体植入情况下,ACL缺失并不会导致UKA术后应力异常增大,会导致在膝关节伸直位时位移增加。     

Anterior tibial loading on the calf enhances anterior tibial translation in the anterior cruciate ligament deficient knee in the anterior gravity radiographic view

BackgroundLateral radiograph in the prone position with the knee flexed at 15° (anterior gravity view (AGV)) is useful as a screening for anterior cruciate ligament (ACL) injuries, while it is sometimes difficult to find the side-to-side difference (SSD) in anterior tibial translation. Thus, we applied a weight (three kilograms) around the lower leg to increase anterior tibial translation. We aimed to determine whether weight load confers an advantage in visualizing anterior knee laxity in ACL injuries.MethodsFifty-eight patients with confirmed unilateral ACL tears from February 2012 to April 2014 had consented to participate in this study. Lateral radiographs for both knees were taken in AGV and in AGV with a three-kilogram weight load applied to the proximal lower leg. Then, the SSD of tibial position related to the femur was measured in these radiographs.ResultsThe SSD with the weight was significantly greater than that without the weight (5.9 ± 2.1 and 3.5 ± 1.6 mm, respectively, p < 0.01). The ratio of patients with SSD of three millimeters or more in AGV with the weight was also significantly larger than that without the weight (p < 0.01).ConclusionsThe anterior laxity in AGV with the three-kilogram weight is larger than that without the weight. Thus, the AGV with the weight could be one of the helpful radiographic technique for auxiliary diagnosis of ACL injury.Level of evidenceCohort study, Level IV.     

The influence of tibial slope on the graft in combined high tibial osteotomy and anterior cruciate ligament reconstruction

Background

Young patients with severe medial osteoarthritis, varus malalignment and insufficiency of the anterior cruciate ligament (ACL) are difficult to treat. The tibial slope has gained attention with regard to osteotomies and ligamentous instability. The purpose was to evaluate the outcome of combined high tibial osteotomy (HTO), ACL reconstruction and chondral resurfacing (CR, abrasion plus microfracture), and to analyse graft failure rates with regard to the tibial slope.

Hamstrings and the anterior cruciate ligament deficient knee

This article outlines the background and preliminary results of the work I undertook during a year of full time research supported by the BASK Knee Research Fellowship. The work was done at the Oxford Orthopaedic Engineering Centre (OOEC). The chance to come out of full time clinical work should in my opinion always be taken. It allows you time to think in a little more depth about a particular area of interest and to work with people in full time research. I found that working alongside the Biomechanical Engineers and their PhD students was mutually beneficial. They learn more about the background to the clinical problems requiring their input, whilst the Orthopaedic trainees undertaking projects in the department learnt a more rigorous approach to our methodology.     

Survivorship and patient satisfaction of a fixed bearing unicompartmental knee arthroplasty incorporating an all-polyethylene tibial component

We report the survivorship of 91 fixed bearing unicompartmental arthroplasties with all-polyethylene tibial components (Preservation DePuy UK), which were used for medial compartment osteoarthritis in 79 patients between 2004 and 2007. The satisfaction level of patients who had not undergone revision of the implant was also recorded. For comparison, we reviewed 49 mobile bearing unicompartmental arthroplasties (Oxford UKA Biomet UK Ltd), which had been used in 44 patients between 1998 and 2007. Mean length of follow-up of patients with the fixed bearing implant was 44.7 months (range 24-74 months) and for the mobile bearing replacement, the mean follow-up was 67.6 months (24-119). In the fixed bearing design, at maximum follow-up period of 74 months, eight implants (8.8%) had been revised (or were listed for revision) to Total Knee Replacement and in the mobile bearing design over the maximum follow-up period of 119 months there had been only one revision (2.0%). Patients who had not undergone revision were asked if they were satisfied with their knee following the unicompartmental arthroplasty. In the fixed bearing design, 83.5% said that they were satisfied with the outcome of the operation compared to 93.9% of the patients receiving the mobile bearing design. We conclude that there is a higher incidence of revision of this fixed bearing design using an all-polyethylene tibial component compared to the mobile bearing design. We found that those patients who had not required revision had a lower rate of satisfaction with the fixed bearing compared to the mobile bearing design.     

活动平台单髁膝关节置换胫骨后倾的有限元分析

背景：目前单髁膝关节置换中胫骨假体后倾角度的选择存在较多争议,相关的生物力学研究较少。 目的：通过有限元分析结果寻求活动平台单髁膝关节置换中合理胫骨后倾的角度。 方法：运用三维重建技术及有限元前处理技术建立正常膝关节有限元模型,并进行验证,在此基础上建立不同胫骨假体后倾角度的单髁膝关节置换有限元模型,统一边界条件和载荷,行有限元分析。 结果与结论：成功建立了不同胫骨后倾角度的单髁膝关节置换有限元模型,分析结果发现增大胫骨假体后倾可使胫骨后内侧皮质及松质骨应力逐渐增加,且增大了外侧间室载荷和软骨接触应力,而胫骨前倾使胫骨前内侧皮质应力明显增加。推荐活动平台单髁膝关节置换中选择0°-7°胫骨假体后倾。 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     

膝关节单髁置换活动与固定平台短期疗效分析

目的比较内侧膝关节单髁假体置换术中活动平台和固定平台治疗膝关节骨关节炎的短期疗效,探讨不同假体翻修率的差异以及并发症的不同。方法回顾性分析2015年5月至2016年12月收治的113例(133膝)膝关节内侧骨关节炎患者资料。根据假体不同分为活动平台和固定平台两组。术后比较两组患者膝关节疼痛、关节活动度、美国膝关节协会评分(Knee Society Score,KSS)等。结果术后患者均获得随访,随访时间6~24个月,平均17.5个月,随访中1例活动平台组患者术后4个月发生半月板衬垫移位脱出,1例活动平台组、1例固定平台组患者术后出现切口红肿破溃。随访期间无一例发生关节内感染以及假体松动移位等。活动平台组KSS评分术前为(48.45±9.17)分,术后为(84.54±8.44)分;固定平台组KSS评分术前为(49.88±12.02)分,术后为(86.40±7.18)分,术前与术后比较,差异有统计学意义。组间KSS评分比较,差异无统计学意义。结论单髁膝关节置换治疗膝关节内侧间室骨关节炎在术后的短期随访中活动平台与固定平台术后的临床结果无明显差异;短期内两种平台假体的翻修率低,但导致翻修的并发症有所不同。     

Conversion of lateral unicompartmental arthroplasty to anterior cruciate retaining tricompartmental knee arthroplasty

This case report presents the conversion of a lateral unicompartmental arthroplasty (UKA) to an anterior cruciate retaining tricompartmental knee arthroplasty. The patient presented with disease progression to the medial and patellofemoral compartments of the knee, in addition to significant varus deformity. During revision surgery, the previously implanted UKA device was found to be well fixed and in good condition. The conventional treatment option would be conversion to total knee arthroplasty (TKA). However, in this case conversion to a tricompartmental, ligament sparing arthroplasty via implantation of a bicompartmental knee arthroplasty (BKA) device was found to be feasible. In UKA revision cases where the device is functional, the current surgical approach may be an appropriate alternative to conventional TKA.     

Minimum 10-year outcomes of a fixed bearing all-polyethylene unicompartmental knee arthroplasty used to treat medial osteoarthritis

BackgroundUnicompartmental knee arthroplasty (UKA) accounts for 8.9% of knee arthroplasty procedures in England, Wales and Northern Ireland. Fixed bearing UKA designs have shown favourable survivorship in registries when compared with mobile bearings but some studies suggest poor survival of all-polyethylene fixed tibial bearings. This study analyses long-term follow-up of patients with a medial fixed all-polyethylene tibial bearing UKA and reports survivorship and 10-year clinical outcomes.MethodsData was collected prospectively for 214 medial unicompartmental all-polyethylene tibial bearing UKAs implanted in 184 patients at our tertiary referral centre between November 2002 and December 2007. The indication was osteoarthritis in all but one patient. Patient reported outcome scores were documented pre-operatively and at five, eight, 10 and 12 years of follow-up. The mean patient age was 70 years (range 41–87).ResultsOutcome and survivorship data were collected for 214 medial all-polyethylene tibial bearing UKAs. There were outcomes recorded for 83 UKAs with at least 10-year follow-up. Twenty-four patients underwent revision of their UKA at an average of 5.84 years after the primary procedure. Kaplan–Meier analysis demonstrated survivorship of 89.1% at 10 years and the OKS, AKSS and WOMAC patient reported outcomes remained significantly improved in comparison to preoperatively. For those 70 years or older, 10-year survivorship was 92.4%, compared to 85.0% for those under 70 years old.ConclusionMedial fixed all-polyethylene tibial bearing UKA demonstrates acceptable long-term survivorship and patient outcomes. It appears to be a suitable option for the treatment of medial compartment OA, particularly in older patients.     

Fracture of the tibial tubercle following anterior cruciate ligament reconstruction

A case is presented of a traumatic avulsion fracture of part of the tibial tubercle after harvesting of the central third of the patellar tendon, with bone blocks, for anterior cruciate ligament (ACL) reconstruction. The literature is reviewed. This injury has not been reported previously.     

Effect of tibial component overhang on survivorship in medial mobile-bearing unicompartmental knee arthroplasty

BackgroundSome studies have shown that the position of the tibial component in Oxford unicompartmental knee arthroplasty with a mobile bearing will affect the clinical outcome of patients. Hence, our study aimed to investigate the relationship between the overhang distance of the tibial component and the survival of the implant.MethodsA retrospective analysis of patients who underwent unicompartmental knee arthroplasty at the same institution from 2014 to 2018 was presented. The study was divided into three groups: minor underhang group (underhang between −3 and 0 mm); minor overhang group (overhang 0–3 mm); and major overhang group (overhang ≥ 3 mm). Demographic and clinical profile characteristics of each group were compared, and survival curves of each group were also compared using Kaplan–Meier and modeled using multivariate Cox regression.ResultsA total of 351 knees were included in this study with a minimum follow up of three years and a mean follow up of 4.8 ± 1.5 years. The revision rates in each group were 3.6% (minor underhang group), 2.7% (minor overhang group), and 20.9% (major overhang group) (P < 0.001). From the three groups’ cumulative survival rates, the major overhang group was significantly lower than the other two groups (log rank P < 0.001). Multivariate Cox regression showed an association between the major overhang group and implant survival rate (hazard ratio = 7.515, 95% confidence interval = 2.500–22.593, P < 0.001)ConclusionThe risk of revision will increase if the tibial component overhangs more than 3 mm medially. Moreover, the reasons for revision are generally bearing dislocation and aseptic loosening.     

Notchplasty in anterior cruciate ligament reconstruction in the setting of passive anterior tibial subluxation

PurposeIn an effort to minimize graft impingement among various ACL deficient states, we sought to quantitatively determine requirements for bone resection during notchplasty with respect to both volumetric amount and location.MethodsA validated method was used to evaluate Magnetic Resonance Imaging scans. We measured the ATT of the medial and lateral compartments in the following four states: intact ACL (27 patients), acute ACL disruption; < 2 months post-injury (76 patients), chronic ACL disruption; 12 months post-injury (42 patients) and failed ACL reconstruction (75 patients). Subsequently, 11 cadaveric knees underwent Computed Tomography (CT) scanning. Specialized software allowed virtual anterior translation of the tibia according to the average ATT measured on MRI. Impingement volume was analyzed by performing virtual ACLRs onto the various associated CT scans. Location was analyzed by overlaying an on-screen protractor. The center of the notch was defined as 0°.ResultsAverage impingement volume changed significantly in the various groups compared to the intact ACL group (acute 577 ± 200 mm³, chronic 615 ± 199 mm³, failed ACLR 678 ± 210 mm³, p = 0.0001). The location of the required notchplasty of the distal femoral wall border did not change significantly. The proximal femoral border moved significantly towards the center of the notch (acute 8.6° ± 4.8°, chronic 7.8° ± 4.2° (p = 0.013), failed ACLR 5.1° ± 5.9° (p = 0.002)).ConclusionOur data suggests that attention should be paid peri-operatively to the required volume and location of notchplasty among the various ACL deficient states to minimize graft impingement.     

前交叉韧带胫骨附着处临床解剖学研究

目的 研究前交叉韧带(ACL)胫骨附着处的解剖形态学特点,并探讨ACL胫骨附着处测量值埘选择ACL重建方式的意义.方法 对10例福尔马林处理的成人膝关节标本进行解剖.在屈伸膝关节时根据ACL纤维张力区分前内束和后外束,然后从胫骨附着处切断韧带,用Photoshop软件测量附着处的相关数据.结果 ACL存在着两个不同的功能束,即前内束和后外束;胫骨附着处的形状不规则,可分为倒三角形、椭1形及四边形三种;ACL胫骨附着处的前后径与横径分别为(17.89±2.44)mm、(13.85±1.79)mm;前内束和后外束胫骨附着处的面积分别为(101.18±32.28)m㎡、(77.61±19.86)m㎡;两束中心点连线的距离为(8.03±1.51)mm.结论 本研究改进的数字图像测量方法是一种既实用又廉价的测量方法;ACL胫骨附着处测量值可作为选择ACL重建方式的参考.     

Validation of the Thessaly test for detecting meniscal tears in anterior cruciate deficient knees

Meniscal injuries are frequently associated with anterior cruciate ligament (ACL) tears. Clinical tests that are useful for detecting meniscal tears may not be valid in this setting. The Thessaly test, a newly described dynamic clinical examination, has been shown to have a very high diagnostic accuracy for detecting meniscal tears. This study evaluates the accuracy of the Thessaly test in patients with combined ACL and meniscus injuries. We examined eighty patients with ACL deficiency for meniscal injuries using the Thessaly test (at 20° of knee flexion), the lateral and medial joint line tenderness tests, and the McMurray test. Examiners were blinded to the MRI report on the conditions of the menisci. All patients underwent arthroscopic ACL reconstruction during which the menisci were evaluated by direct vision and probing. During the Thessaly test, six patients developed severe pain and could not complete the test. Sensitivity, specificity, likelihood ratios and predictive values were calculated for all tests. The Thessaly test had a sensitivity of 79%, specificity of 40%, positive predictive value of 56%, negative predictive value of 66%, positive likelihood ratio of 1.33, negative likelihood ratio of 0.51%, and overall accuracy of 60%. We concluded that the Thesally test has a low specificity in patients with combined ACL and meniscal injuries and can not be recommended as a diagnostic test in this setting.     

The role of meniscal tears and meniscectomy in the mechanical stability of the anterior cruciate ligament deficient knee

Background

The role of an intact meniscus in providing mechanical stability to the knee of anterior cruciate ligament (ACL) deficient and ACL reconstructed patients has not been well studied.

No deterioration of kinematics and cruciate function 10 years after medial unicompartmental arthroplasty

The mechanisms of failure for unicompartmental arthroplasty are poorly understood. There is some suggestion that long term ligament degeneration, particularly of the anterior cruciate ligament (ACL), may affect long term survivorship. This study evaluated whether the cruciate mechanism remained functional in the long term (10 years) following UKA.

Two separate cohorts of patients who had undergone St Georg Sled medial compartmental arthroplasty had knee kinematics assessed using an established fluoroscopic technique. One group (early) was assessed at a mean of 46 months (3.8 years) since surgery, whilst the other (late) was assessed at a mean of 125 months (10.4) following surgery. No significant difference was found in the sagittal plane kinematics between the two groups or in comparison to the control normal knee.

The results suggest that after fixed bearing UKA the cruciate mechanism remains intact over time and the ligaments continue to function similarly to those of the normal knee.     

Combined anterior cruciate reconstruction and Oxford unicompartmental knee arthroplasty: in vivo kinematics

The in vivo kinematics of 10 patients after combined anterior cruciate ligament reconstruction (ACLR group) and Oxford unicompartmental knee arthroplasty (UKA) was compared to those of 10 Oxford UKA patients with an intact ACL (ACLI group) and a group of 22 normal knees. The kinematics during a step-up exercise and a deep knee bend exercise was measured using a fluoroscopic technique. The patellar tendon angle (PTA) to knee flexion angle relationship during both exercises was similar for all three groups of subjects. For the UKA groups the pattern of mobile bearing movement during both exercises was similar. This study demonstrates that normal knee kinematics is achieved in the ACL deficient arthritic knee following ACLR and UKA. As a result these patients, who tend to be young and high demand, have excellent outcome and achieve high levels of function. As the relative position of the components and thus component loading are similar to the ACLI UKA, we would expect similar long term survival.