胫骨平台骨折及膝关节附属结构损伤的MRI诊断

目的评价胫骨平台骨折合并膝关节附属结构损伤的MRI表现.资料与方法 27例胫骨平台骨折病例经X线平片检查后作MRI扫描,分析不同类型胫骨平台骨折所合并的膝关节附属结构损伤的MRI形态学表现.结果 MRI能准确显示骨折所合并的膝关节附属结构的损伤性病变,包括关节软骨断裂、半月板撕裂和移位、侧副韧带和肌腱的撕裂、关节腔脂肪血性积液等,其中双髁骨折引起的损伤最为严重,撕脱骨折引起的损伤较轻.结论 MRI能准确诊断胫骨平台骨折合并的膝关节附属结构损伤,应作为膝关节外伤的常规检查手段.     

Intra-articular knee injuries in patients with knee extensor mechanism ruptures

The knee extensor mechanism is composed of the quadriceps tendon, patella and patellar tendon. Rupture of either the quadriceps tendon or patella tendon is a rare but significant injury. The purpose of our study is to determine if there are any associated injuries with these ruptures necessitating the need for further evaluation such as MRI or arthroscopy. We retrospectively reviewed all patients with ruptures of the knee extensor mechanism who required operative repair at our institution over the last 10 years. We reviewed the chart for any documented associated injury. The type and incidence of associated injuries were recorded. We further divided these patients into two groups: low energy indirect mechanism or high-energy direct impact mechanism. Sixty-four patients met our requirements for inclusion in this study. Thirty-three patients with patellar tendon ruptures and thirty-one patients with quadriceps tendon ruptures were included. Ten out of 33 (30%) patients with a patellar tendon rupture had an associated injury. Four out of 25 (16%) patients with patellar tendon ruptures in the low energy mechanism category had an associated injury. Six out of 8 (75%) patients with a high-energy direct impact patellar tendon rupture had an associated injury. Three out of 31 (10%) patients with quadriceps tendon rupture had an associated injury. The most common associated injuries in the patellar tendon rupture patients were anterior cruciate ligament tears (18%) and medial meniscus tears (18%). We found almost one-third of all patients with a patellar tendon rupture had an associated intra-articular knee injury. We found 10% of patients with quadriceps tendon rupture had an associated intra-articular knee injury. We also found an even higher incidence of associated injuries in patients with high-energy direct impact mechanism patellar tendon ruptures (75%). The most common associated injuries in patients with patellar tendon ruptures were tears of the anterior cruciate ligament (18%) and medial meniscus (18%). We recommend that consideration be given in obtaining a MRI or diagnostic arthroscopy in patients with patellar tendon ruptures especially those with high-energy direct impact mechanism. To our knowledge this has not previously been documented in the literature.     

Hypermobility and Knee Injuries

In brief: The effect of knee joint hypermobility on knee injury is not fully clear. Inherited flexibility probably plays little role in the causes of most knee injuries. The exception is patellar dislocation, which is strongly associated with hypermobility. Discussions of hypermobility often reflect confusion over the difference between flexibility and laxity. In general, flexibility refers to a joint's range of motion and is a function of muscle and tendon tightness, while laxity refers to joint distraction and shear and is a function of ligament tightness. Research on hypermobility has focused on flexibility; the relationship between injury and joint laxity (ligament stability) has not been studied prospectively. Such research could yield information useful for injury prevention.     

Simultaneous rupture of the patellar tendon and the anterior cruciate ligament: a case report and literature review

We report a case of simultaneous rupture of the patellar tendon and the anterior cruciate ligament. This condition was rarely reported in the literature and clinical diagnosis can be difficult. It is frequently associated with injuries of other knee structures. The preferred treatment is immediate primary repair of the patellar tendon and delayed reconstruction of the anterior cruciate ligament.     

交叉韧带损伤的早期手术治疗

目的　探讨膝关节交叉韧带损伤的早期手术治疗方法与效果。方法　分析 1989年 5月～ 1999年 5月收治的 4 1例交叉韧带损伤病例的临床资料。韧带上下止点撕脱骨折 2 9例 ,前交叉韧带实质断裂 12例 ,膝关节合并伤 2 1例。 4 1例均在伤后 1～ 19天内手术。撕脱性骨折用钢丝固定 ;实质断裂直接缝合 5例 ,骨 -膑腱 -骨重建前交叉韧带 7例。结果　在获得随访的 38例中 ,平均随访时间 4 .2年 ,撕脱性骨折手术优良率 88% ;实质断裂直接缝合优良率 2 0 % ,骨 -膑腱 -骨重建优良率 6 0 %。结论　交叉韧带止点撕脱骨折早期手术效果良好 ,实质断裂骨 -膑腱 -骨重建效果较好 ,直接缝合效果较差。     

Fixation of chondral fracture of the weight-bearing area of the lateral femoral condyle in an adolescent

Purely chondral fractures of the distal femur associated with patellar dislocation are uncommon, and treatment varies from fixation to debridement and marrow stimulation techniques. The unusual case reported here involves an adolescent who underwent fixation of a purely chondral fracture involving a large weight-bearing portion of the lateral femoral condyle. Chondral fracture healing was confirmed on follow-up magnetic resonance imaging and arthroscopic examination. This case suggests that fixation of purely chondral fractures can be successful in weight-bearing areas of the knee. Level of evidence V.     

The reverse Segond fracture: not associated with knee dislocation and rarely with posterior cruciate ligament tear

The aims of this study were to assess the incidence of reverse Segond fracture, to examine the associated ligamentous injuries, and to examine how often reverse Segond fracture coexists with a knee dislocation. At a level 1 trauma center, an 11-year period of emergency department multidetector-row computed tomography (MDCT) examinations for knee trauma was evaluated for reverse Segond and Segond fractures. Surgical findings served as the reference standard for intra-articular injuries. The hospital discharge register was searched for the diagnosis of knee dislocation from August 2000 through the end of August 2011. A total of 1,553 knee MDCT examinations were evaluated. Ten patients with a reverse Segond fracture were found, comprising 0.64 % of emergency room acute knee trauma MDCT examinations. Seven patients who had a reverse Segond fracture were operated: Three had an avulsion fracture of the anterior cruciate ligament, one had an avulsion fracture of posterior cruciate ligament, two had a lateral meniscal tear, and two had a medial collateral ligament tear. The ratio of reverse Segond fractures to Segond fractures was 1:4. None of the 71 knee dislocation patients had a reverse Segond fracture. Reverse Segond fracture is a rare finding even in a level 1 trauma center. Cruciate ligament injuries appear to be associated with avulsion fracture, but every patient does not have PCL injury, as previously reported. Our results do not support the association of knee dislocation with reverse Segond fracture.     

急性髌骨外侧脱位的MRI分析

目的 结合损伤机制探讨急性髌骨外侧脱位的MRI特征表现.资料与方法 回顾性分析42例急性髌骨外侧脱位患者的MRI资料,由两名放射科医师共同确定骨髓水肿、骨软骨骨折、髌骨位置、髌骨内侧支持带的损伤、关节积液及其他合并损伤情况.结果 (1)股骨外髁前侧面和髌骨内下关节面骨髓水肿的出现率均为98%(41/42),其中95%(40/42)两处同时出现.其余区域骨髓水肿的出现率仅为7%(3/42).(2)36%(15/42)可见髌骨内后缘骨软骨骨折,10%(4/42)出现股骨外髁骨软骨骨折,其余区域则无.(3)2%(1/42)髌骨仍处于脱位状态,50%(21/42)髌骨呈半脱位,其余48%(20/42)髌骨位置正常.(4)62%(26/42)可见髌骨内侧支持带异常,43%(18/42)合并股内侧斜肌损伤,37%(16/42)合并股外侧肌水肿,7%(3/42)出现髌骨外侧支持带异常,2%(1/42)合并内侧副韧带损伤.(5)100%(42/42)出现关节积液,包括关节积血5例、关节脂血症2例.结论 急性髌骨外侧脱位的MRI表现取决于其特定的损伤机制,股骨外髁前侧面和髌骨内下关节面同时出现的骨髓水肿、髌骨内后缘的骨软骨骨折、髌骨内侧支持带异常、股内侧斜肌和股外侧肌的损伤为常见而又具有特征的MRI征象.     

Imaging patellar complications after knee arthroplasty

The purpose of this study is to describe complications affecting the patella in patients with total or partial knee arthroplasty. We respectively analysed plain-film radiographs, as well as ultrasound images when acquired, in a consecutive series of 1272 patients. The mean interval from knee replacement to patellar complications was 5 years and 7 months (range, 5 months to 14 years). The complications described include fracture, instability, dislocation or luxation, necrosis of the patella, infection of the patella, erosion of the patella, patellar impingement on the prosthesis and patellar or quadricipital tendon tear. We discuss the pathological imaging findings in the patella and their differential diagnosis after knee arthroplasty. Patellar complications after knee arthroplasty are uncommon but often potentially serious.     

Lateral femoral condylar shearing fractures

Lateral femoral condylar shearing fractures occur as the aftermath of acute patellar dislocation. The fracture fragment may be larger than originally appreciated on plain films. Diagnosis depends on identifying the fracture fragment somewhere within the knee joint, and the "donor site" on the lateral femoral condyle. Therefore, MRI or arthroscopy should be performed to identify the true size of the fracture fragment. The larger of these fragments may require surgical intervention with fixing of the fracture fragment onto the lateral condyle with screws. We present the radiographic and clinical findings in seven patients. Electronic Publication     

Imaging pediatric sports injuries: lower extremity

Injuries to pediatric athletes, which are becoming increasingly common, take the form of acute injuries and chronic overuse injuries. Acute injuries of the lower extremity include avulsions of the pelvic apophyses, muscle-tendon injuries, transient dislocation of the patella, ankle sprains, and acute tears of the anterior cruciate ligament and menisci. Magnetic resonance (MR) imaging of the latter 2 injuries should approach the accuracy of MR imaging of the adult knee. Chronic overuse injuries of the lower extremity in this age group include stress fractures, which are most common in the tibia; ankle impingement syndromes; osteochondritis dissecans of the knee and osteochondral lesions of the talus; and traction apophysitis, most commonly presenting as Osgood-Schlatter disease and Sinding-Larsen-Johannson disease, affecting the patellar tendon. Imaging findings of all these lesions are characteristic, and allow radiologists to assist their clinical colleagues in diagnosing and treating pediatric athletic injuries.     

Anatomy of patellar dislocation

Acute patellar dislocation is a common injury that can lead to disabling knee pain and/or recurrent instability. In the past 10 years, research has begun to focus on the injuries associated with acute patellar dislocation, and the specific contributions the injured structures make to patellar stability in intact knees. The implication is that injury to specific structures may have important consequences in converting a previously asymptomatic, although perhaps abnormal, patellofemoral joint into one that is painful and/or unstable. These studies have been intended to improve the precision of surgical treatment for patellar instability, and their results are driving refinements in our surgical indications as well as technique.     

Unusual patellar tendon injury in an adolescent runner with generalised ligamentous laxity.

A case is reported of an acute traction injury of the patellar tendon in a boy of 14 with joint hypermobility. Such injuries are unusual but early diagnosis and surgical repair lead to a good long term outcome. In adolescents participating in sports, the awareness of the possibility of a rare knee extensor mechanism injury is essential for a successful outcome.     

Iliotibial band avulsion fracture: a case report with differential diagnosis

Avulsion injuries of the knee are common sequelae of significant trauma given the number of ligamentous and tendinous insertions around the joint. Commonly discussed avulsion fractures of the lateral knee include the Segond fracture of the lateral tibial plateau and the arcuate complex avulsion fracture of the fibular styloid process. A less common avulsion fracture is the iliotibial (IT) band avulsion fracture involving the anterolateral corner of the tibia (Gerdy’s tubercle). It is crucial to identify IT band avulsion fractures because of the frequent associated internal derangements of the knee. This case report describes the imaging of an acute IT band avulsion fracture and compares these findings with other lateral knee avulsion fractures.     

Patellar fractures associated with medial-third bone-patellar tendon-bone autograft ACL reconstruction

Patella fractures following anterior cruciate ligament (ACL) reconstruction are a recognized but rarely reported complication. To our knowledge, 24 reports of patella fractures after ACL reconstruction using the central-third patella-tendon autograft have been reported in the literature. Patellar fractures associated with the use of the medial-third bone-patellar tendon-bone autograft have not been reported. This article describes four cases of patellar fractures in 478 ACL reconstructions between 1992 and 1999, using the medial third of the patellar tendon graft. All of them were transverse fractures of the patella but only one was displaced. All patients suffered local injury to the donor knee between 2 and 4 months postoperatively. No significant differences in the final outcome were noticed between the cases complicated with patellar fracture and those with uncomplicated ACL reconstructions.     

Impingement fracture of the anteromedial tibial margin: a radiographic sign of combined posterolateral complex and posterior cruciate ligament disruption

Marginal fractures of the tibial plateau are associated with a high incidence of soft tissue injuries to the stabilising structures of the knee joint. Injuries to the anterior cruciate ligament are associated with the Segond fracture and impingement fractures of the posteromedial tibial plateau. Recognition of these fractures aids diagnosis of these injuries. Marginal fractures of the tibial plateau associated with posterior cruciate ligament injuries are less common, though recently a ”reverse” Segond fracture has been recognised. We describe a fracture of the anteromedial tibial plateau associated with complete disruption of the posterior cruciate ligament and posterolateral complex. Received: 12 June 2000 Revision requested: 17 July 2000 Revision received: 23 October 2000 Accepted: 26 October 2000     

Irreducible anterior dislocation of the shoulder due to soft tissue interposition of subscapularis tendon

The shoulder joint is the most unstable joint in the body and is easily dislocated. Anterior shoulder dislocation is the commonest and can be associated with glenoid and humeral fractures. Anterior shoulder dislocations are not infrequently associated with cuff tendon tears; however, anterior shoulder dislocation is easily reducible. Irreducible anterior dislocation of the glenohumeral joint is uncommon, and this could be due to bony as well as soft tissue causes. Persistent anterior dislocation due to torn subscapularis interposition in the glenohumeral joint is very rare, and only a few operative cases have been reported in the literature. We present MR features of one such case and a literature review.     

低场磁共振成像对膝关节外伤的诊断敏感性

目的探讨低场强（0．35T）磁共振成像对膝关节外伤的诊断敏感性，并与X线平片及常规CT检查结果比较。方法64例有膝关节外伤史及相应临床表现的患者，于外伤后1d至3个月内均经自旋回波（SE）和快速自旋回波（FSE）磁共振成像，21例又经X线平片检查，10例又经常规CT检查。对所有患者的MRI表现进行了分析，并与X线及CT所见进行了对比。结果在接受X线平片检查的21例中，各种异常见于15例，其诊断敏感性为72％。在常规cT检查的10例中，骨折、隐匿性骨折及半月板损伤分别见于2，3和1例，其诊断敏感性为60％。在MRI检查的64例中，骨挫伤见于40例（66处），合关骨折及隐匿性骨折23处，合并韧带损伤31例，合并半月板损伤23例，仅2例未见异常。MRI诊断膝关节外伤的敏感性为97％。结论MRI对膝关节外伤的诊断敏感性显著高于X线平片或常规CT。合理选用磁共振扫描序列与参数，能够准确地诊断膝关节外伤。     

ACR Appropriateness Criteria® Acute Trauma to the Knee

There are more than 1 million visits to the ER annually in the United States for acute knee trauma. Many of these are twisting injuries in young patients who can walk and bear weight, and emergent radiography is not required. Several clinical decision rules have been devised that can considerably reduce the number of radiographic studies ordered without missing a clinically significant fracture. Although fractures are seen on only 5% of emergency department knee radiographs, 86% of knee fractures result from blunt trauma. In patients with falls or twisting injuries who have focal tenderness, effusion, or inability to bear weight, radiography should be the first imaging study performed. If radiography shows no fracture, MRI is best for evaluating for a suspected meniscal or ligament tear or patellar dislocation. Patients with knee dislocation should undergo radiography and MRI, as well as fluoroscopic angiography, CT angiography, or MR angiography. The ACR Appropriateness Criteria(?) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.     

Tendon entrapments and dislocations in ankle and hindfoot fractures: evaluation with multidetector computed tomography

The purpose of this study was to assess the incidence of tendon entrapments and tendon dislocations associated with ankle and hindfoot fractures in patients studied by multidetector computed tomography (MDCT). Additionally, we describe particular tendon injuries associated with specific fractures. This was a retrospective review of all individuals with a trauma-protocol CT for suspected ankle and/or hindfoot fractures during a consecutive 41-month time period at a single Level I Trauma Center. Each patient’s images were evaluated by two radiologists and an orthopedic surgeon for tendon entrapment, tendon dislocation, and bone(s) fractured or dislocated. There were 398 patients with ankle and/or hindfoot fractures that showed tendon entrapment or dislocation in 64 (16.1 %) patients. There were 30 (46.9 %) patients with 40 tendon entrapments, 31 (48.4 %) patients with 59 tendon dislocations, and three (4.7 %) patients with both tendon entrapment and dislocation. All patients with tendon entrapments were seen with either pilon fractures and/or a combination of posterior, medial, or lateral malleolar fractures. The most frequently entrapped tendon was the posterior tibialis tendon (PTT) in 27 patients (27/30, 90.0 %). The peroneal tendons were the most frequently dislocated, representing 27 (87.1 %) of patients with tendon dislocation; all resulted from a talar or calcaneal fracture or subluxation. This study demonstrates that tendon entrapments and tendon dislocations are commonly seen in complex fractures of the ankle and hindfoot. Pilon fractures were associated with the majority of tendon entrapments, whereas calcaneus fractures were associated with the majority of tendon dislocations.