Semimembranosus tendon avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament tear and capsular rupture

Semimembranosus tendon avulsion fractures are an uncommon occurrence and are often associated with anterior cruciate ligament (ACL) and medial meniscus tears. We present the imaging features of an unusual case of semimembranosus avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament (PCL) tear, medial meniscus tear, and capsular rupture in a 26-year-old man with a football injury.     

Articular cartilage injury of the posterior lateral tibial plateau associated with acute anterior cruciate ligament injury

Thirty-nine knees in 39 patients with recent anterior cruciate ligament (ACL) rupture (age 14–55 years; with a mean age of 22.8 years) were selected from our cases of ACL reconstruction from July 2005 to June 2006, to take part in a study on articular cartilage injury of the posterior lateral tibial plateau associated with acute ACL injury and on the correlation between bone bruises depicted on MRI and cartilage injury of the posterior lateral tibial plateau detected at arthroscopic ACL reconstruction. Using preoperative MRI, we evaluated whether there were bone bruises or not in the lateral compartment of the knee and divided them accordingly into two groups: the bone bruise positive group and the negative group. The differences in the proportions of the lateral meniscus (LM) tears and the cartilage injuries in the two groups were evaluated using Fisher’s exact probability test. Thirty-five cases out of 39 arthroscopic ACL reconstructions (89.7%) were regarded as bone bruise positive in the lateral compartment and four cases (10.3%) were regarded as negative. At arthroscopic ACL reconstruction, 33 cases (84.6%) had tears in the LM posterior horn, 34 cases (87.2%) had articular cartilage injuries in the lateral femoral condyle and 29 cases (74.3%) had articular cartilage injuries in the posterior lateral tibial plateau. From 35 bone bruise positive cases, 32 cases (91.4%) had tears in the LM posterior horn, 33 cases (94.3%) had articular cartilage injuries in the lateral femoral condyle and 28 cases (80%) had articular cartilage injuries in the posterior lateral tibial plateau. Of four bone bruise negative cases, one case (25%) had a tear in the LM posterior horn, articular cartilage injury of the lateral femoral condyle and of the posterior lateral tibial plateau. There was a statistically significant correlation between the proportion of bone bruise and cartilage injury of the lateral femoral condyle (P = 0.004), that of the posterior lateral tibial plateau (P = 0.04) and that of tears in the LM posterior horn (P = 0.008). This current study has demonstrated that we need to pay attention to cartilage damage of the posterior lateral tibial plateau as well as to posterior horn tears in LM, when acute ACL injury is shown. We also have to ensure that we follow the long-term progress of cartilage injuries, with the aim of preventing these injuries becoming osteoarthritis after ACL reconstruction.     

Occult fracture patterns of the knee associated with anterior cruciate ligament tears: assessment with MR imaging.

One hundred consecutive magnetic resonance (MR) images of the knee in patients with acute complete anterior cruciate ligament (ACL) tears were reviewed to evaluate the prevalence and patterns of associated occult fractures. Eighty-nine occult fractures were identified in 56 knees. All occult fractures were in the posterior aspect of the lateral tibial plateau. Of these, occult fractures were isolated in 24 cases (43%) and were in combination with fractures in the middle aspect of the lateral femoral condyle in 26 (46%), with fractures in the posterior aspect of the medial tibial plateau in four (7%), and with fractures involving all three areas in one (2%). Disruption of the ACL under valgus stress leads to anterior translation of the tibia and relative external rotation of the femur. This allows impaction of the posterior portion of the lateral tibial plateau against the middle of the lateral femoral condyle and accounts for the unique pattern of occult fractures associated with ACL tears. An occult fracture of the posterior lateral tibial plateau with or without an associated fracture in the lateral femoral condyle ("kissing contusion") is a relatively frequent finding in acute ACL tears and, when present, is highly suggestive of such an associated tear.     

Knee dislocations: a magnetic resonance imaging study correlated with clinical and operative findings

OBJECTIVES: Our objectives were to determine retrospectively the prevalence, patients' demographics, mechanism of injury, combination of torn ligaments, associated intra-articular and extra-articular injuries, fractures, bone bruises, femoral-tibial alignment and neurovascular complications of knee dislocations as evaluated by magnetic resonance (MR) imaging. MATERIALS AND METHODS: From 17,698 consecutive knee examinations by magnetic resonance imaging (MRI) over a 6-year period, 20 patients with knee dislocations were identified. The medical records of these patients were subsequently reviewed for relevant clinical history, management and operative findings. RESULTS: The prevalence of knee dislocations was 0.11% [95% confidence interval (95% CI) 0.06-0.16)]. There were 16 male patients and four female patients, with ages ranging from 15 years to 76 years (mean 31 years). Fifteen patients had low-velocity injuries (75%), of which 11 were amateur sports related and four were from falls. Four patients (20%) had suffered high-velocity trauma (motor vehicle accidents). One patient had no history available. Anatomic alignment was present at imaging in 16 patients (80%). Eighteen patients had three-ligament tears, two had four-ligament tears. The four-ligament tears occurred with low-velocity injuries. The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were torn in every patient; the lateral collateral ligament (LCL) was torn in 50%, and the medial collateral ligament (MCL) in 60%. Intra-articular injuries included meniscal tears (five in four patients), fractures (eight in seven patients), bone bruises (15 patients), and patellar retinaculum tears (eight partial, two complete). The most common extra-articular injury was a complete biceps femoris tendon tear (five, 25%). There were two popliteal tendon tears and one iliotibial band tear. One patient had received a vascular injury following a motor vehicle accident (MVA) and had been treated prior to undergoing MRI. Bone bruises (unrelated to fractures), four-ligament tears, biceps femoris tears, and popliteus tendon tears were encountered only in the low-velocity knee dislocations. Twelve were treated surgically, five conservatively, and three had been lost to follow-up. The biceps femoris tendon was repaired in every patient who was treated surgically. CONCLUSIONS: Knee dislocations occurred more commonly in low-velocity injuries than in high-velocity injuries, predominantly affecting amateur athletes. Biceps femoris tendon tears were the most common extra-articular injury requiring surgery. Neurovascular injury (5%) was uncommon. At imaging, femoral-tibial alignment was anatomic in the majority of patients.     

膝关节前十字韧带撕裂的MRI诊断价值

目的：评价MRI诊断前十字韧带撕裂的价值。方法：对临床拟诊为膝关节前十字韧带撕裂的12例患者，对照分析其MRI资料及手术结果。结果：MRI矢状面9例，冠状面7例显示前十字韧带撕裂。12例中8例前十字韧带内有不规则高信号，4例前十字韧带前缘呈不规则波浪状，1例前十字韧带不连续。12例中6例伴后外侧胜分平台分析。MRI确诊11例。结论：MRI诊断前十字韧带撕裂是有价值的，膝关节后外侧胜管平台分析高度提示急性前十字韧带撕裂。     

Anterior cruciate ligament tears: MR imaging-based diagnosis in a pediatric population

PURPOSE: To evaluate the diagnostic accuracy of primary and secondary magnetic resonance (MR) imaging findings of anterior cruciate ligament (ACL) tears in young patients with immature skeletal systems. MATERIALS AND METHODS: MR images obtained in 43 patients aged 5-16 years who underwent arthroscopy were retrospectively reviewed. Two reviewers evaluated primary findings (abnormal signal intensity, abnormal course as defined by Blumensaat angle, and discontinuity), secondary findings (bone bruise in lateral compartment, anterior tibial displacement, uncovering of posterior horn of lateral meniscus, posterior cruciate ligament line, and posterior cruciate angle), and meniscal and other ligamentous injuries. RESULTS: There were 19 ACL tears and 24 intact ACLs. Overall sensitivity and specificity of MR imaging in detecting ACL tears were 95% and 88%, respectively. Sensitivities of the primary findings were 94% for abnormal Blumensaat angle; 79%, abnormal signal intensity; and 21% discontinuity. The specificity of all primary findings was 88% or greater. The sensitivity and specificity of the secondary findings, respectively, were 68% and 88% for bone bruise; 63% and 92%, anterior tibial displacement; 42% and 96%, uncovered posterior horn of lateral meniscus; 68% and 92%, positive posterior cruciate line; and 74% and 71%, abnormal posterior cruciate angle. Fifteen (79%) patients had meniscal tears, and five (26%) had collateral ligament injuries. CONCLUSION: Primary and secondary findings of ACL tears in young patients have high specificity and are useful for diagnosis.     

MRI of anterior cruciate ligament injuries and associated findings in the pediatric knee: changes with skeletal maturation

OBJECTIVE: The objective of our study was to evaluate the MRI characteristics of anterior cruciate ligament (ACL) injuries and associated findings relative to skeletal maturity. We also contrast the frequency of findings in this younger population to adult data. MATERIALS AND METHODS: Eighty-two consecutive knees with an MRI report diagnosis of ACL injury (partial tear, sprain, or complete tear) or tibial spine avulsion fracture imaged over 4 years were retrospectively reviewed. Patients were grouped by degree of skeletal maturity as determined from the MR images. The examinations were reviewed for the type of ACL injury, secondary imaging findings, and associated knee injuries. Findings were correlated to skeletal maturity, and frequencies were compared with adult data. RESULTS: ACL injuries were more common in boys in the skeletally immature group, but more common in girls in the skeletally mature group (p = 0.03). Tibial spine avulsion fractures were most common in skeletally immature patients (p < 0.01), whereas complete tears of the ACL were most common in skeletally mature patients. Associated injuries were less common in the skeletally immature group, but this trend did not reach statistical significance. Most secondary signs of ACL injuries occurred at similar rates in all groups with frequencies similar to those reported in adults. CONCLUSION: ACL injuries in skeletally immature patients are seen more often in boys. Tibial avulsion fractures and partial tears are more common in younger, less rigid skeletons that may absorb the forces of trauma. As children mature, complete ACL tears and associated injuries occur in frequencies approaching those patterns seen in adults. Similarly, skeletally mature girls are affected more often than mature boys.     

The knee: surface-coil MR imaging at 1.5 T1

Seven normal knees (in five volunteers) and seven injured knees (in seven patients) were examined by high-resolution magnetic resonance (MR) imaging at 1.5 T with a surface coil. Seven medial meniscal tears, three anterior cruciate ligament tears, one posterior cruciate ligament avulsion, an old osteochondral fracture, femoral condylar chondromalacia, and one case of semimembranous tendon reinsertion were identified. MR images correlated well with recent double-contrast arthrograms or results of surgery. All tears were identified in both the sagittal and coronal planes. Because of its ability to demonstrate small meniscal lesions and ligamentous injuries readily, MR imaging with a surface coil may eventually replace the more invasive arthrography.     

Combined osteochondral fracture of the posterolateral tibial plateau and Segond fracture with anterior cruciate ligament injury in a skeletally immature patient

A case of a 14-year-old boy with a rare injury—an osteochondral fracture of the posterolateral tibial plateau associated with the anterior cruciate ligament (ACL) rapture, and Segond fracture characterized by an avulsion fracture of the lateral tibial plateau—is reported. This case was noteworthy because it involved a rare combination of ACL injuries. This injury was thought to be caused by the impaction between the posterior aspect of the lateral tibial plateau and the lateral femoral condyle during internal rotational displacement of the knee joint at the time of injury, because the osteochondral fracture of the posterolateral tibial plateau matched the site where the bone bruise was observed.     

MR imaging of posterior cruciate ligament injuries

Posterior cruciate ligament(PCL) injuries are less frequent than anterior cruciate ligament(ACL) injuries, but are presumably more common than once thought. Thirty-nine patients with PCL injuries identified on MR images were studied. The criteria for PCL injury were complete tear, partial tear, and avulsion fracture. The approximate site of a partial tear was categorized as proximal, midsubstance, distal, or combination. Fourteen patients(35.9%) had complete tears of the PCL, 21 patients(53.8%) had partial tears, and four patients(10.3%) had avulsion fractures. A total of 12 patients (30.7%) had isolated PCL injuries, while the remaining 27 patients demonstrated evidence of other coexistent knee injuries, such as meniscal tears and ligamentous injuries. Of coexistent knee injuries, meniscal tears(18 patients, 46.2%) were most often seen.     

急性前交叉韧带断裂合并膝关节骨挫伤的临床研究

目的 :总结前交叉韧带急性断裂时骨挫伤的不同类型和分布 ,探讨骨挫伤与关节软骨损伤的关系。方法 :回顾性研究 37例前交叉韧带急性断裂合并膝关节骨挫伤患者的影像学和临床资料 ,分析前交叉韧带急性断裂时骨挫伤的MRI不同表现类型、分布以及关节镜下软骨损伤的情况。结果 :MRI显示本组病例骨挫伤共 5 7处 ,其中Ⅰ型 1 4处 (2 4 .6 %) ,Ⅱ型 32处 (5 6 .1 %) ,Ⅲ型 3处(5 .3%) ,Ⅳ型 6处 (1 0 .5 %) ,Ⅴ型 2处 (3.5 %)。共 5 4处 (94 .7%)骨挫伤位于外侧间室 ,其中股骨外髁骨挫伤 31处 ,胫骨外侧平台骨挫伤 2 3处。经关节镜下手术发现 9处 (1 5 .8%)骨挫伤部位有软骨损伤表现。结论 :急性前交叉韧带断裂时 ,骨挫伤通常发生在外侧间室 ,尤其集中在外侧股骨髁前部以及外侧胫骨平台后部。关节镜下软骨损伤与骨挫伤并非一一对应的关系。     

Avulsion of the posteromedial tibial plateau by the semimembranosus tendon: diagnosis with MR imaging

Two sports-related knee injuries resulted in small fractures at the posteromedial corner of the tibial plateau. Magnetic resonance imaging demonstrated findings consistent with an avulsion injury at the semimembranosus insertion, as well as a similar pattern of internal derangement in both cases.     

Avulsion fracture of the head of the fibula (the "arcuate" sign): MR imaging findings predictive of injuries to the posterolateral ligaments and posterior cruciate ligament

OBJECTIVE: The purpose of this study was to describe the significance of an avulsion fracture of the head of the fibula ("arcuate" sign) and its association with injuries of the knee on MR imaging. MATERIALS AND METHODS: We conducted a retrospective search of 2318 patients who underwent conventional radiography and MR imaging after an episode of knee trauma. Patients were included in this study if they had an avulsion fracture of the head of the fibula revealed on conventional radiography and underwent arthroscopy. Thirteen patients, all of whom were men, satisfied the inclusion criteria. Ten patients underwent further explorative surgery. The clinical, radiographic, MR imaging, and surgical findings were then reviewed. RESULTS: The avulsion fracture of the styloid process of the fibular head was apparently related to injuries of the arcuate complex in all 13 patients. Radiographically, the bony fragment was horizontally oriented and similar in size in most patients, ranging from 8 to 10 mm in length and from 2 to 5 mm in width. On MR imaging, the fibular avulsion was identified in 11 of the 13 patients. The other two patients had marrow edema in the fibular styloid process, although the avulsion fracture was not evident. All patients had injuries of the posterior cruciate ligament (six tibial avulsions, seven midsubstance tears). No patient had a tear of the anterior cruciate ligament. Disruption of the lateral collateral ligament was evident in seven patients, and one patient had a tear of the popliteal tendon. During surgery, six patients had disruption of the arcuate complex, but this disruption could not be identified on the MR images. CONCLUSION: An avulsion fracture of the fibular head generally involves the styloid process and causes injury of some of the major stabilizers in the posterolateral corner. Avulsion fractures are strongly associated with disruption of the posterior cruciate ligament.     

Diagnosis of popliteus injuries with MR imaging

Objective. Popliteal muscle and tendon injuries are thought to be unusual. This report describes the magnetic resonance (MR) appearances of popliteus muscle and tendon injuries. Design and patients. The study included 24 patients where the diagnoses of popliteal injuries were prospectively made based on MR appearances. The study group was taken from 2412 consecutive knee MRIs. The injuries were characterized as to involving the muscular or tendinous portions of the popliteus apparatus. Results. In 95.8% (23/24) of patients, the tears of the popliteus involved the muscular portion. The injuries were either partial and interstitial or complete. Three patients had tears of both the muscular and tendinous portions or the tendon alone. The anterior and posterior cruciate ligaments were torn in 16.7% (4/24) and 29.2% (7/24) of patients, respectively. There were medial and lateral meniscal tears in 45.8% (11/24) and 25% (6/24) of patients, respectively. There were injuries of the medial and lateral collateral ligaments in 8.3% (2/24) and 4.2% (1/24) of patients, respectively. Bone bruises and/or fractures were seen in 33.3% (8/24) patients. In 8.3% (2/24) of patients, the popliteus injury was an isolated finding. Conclusion. Popliteus muscle and tendon injuries are not uncommon. They usually occur in conjunction with other significant injuries of the knee and can be characterized with MR imaging.Presented at RSNA, Chicago, Illinois, December 1992     

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.     

膝关节韧带损伤与胫骨平台骨折Schatzker及AO分型的相关性分析

目的分析膝关节韧带损伤与胫骨平台骨折Schatzker分型及AO分型的相关性。方法选取2018年1月至2019年6月厦门大学附属福州第二医院骨科收治的28例胫骨平台骨折合并膝关节韧带损伤患者作为研究对象,根据Schatzker分型及AO分型系统对胫骨平台骨折进行分型,同时判定前交叉韧带(anterior cruciate ligament,ACL)、后交叉韧带(posterior cruciate ligament,PCL)、内侧副韧带(medial collateral ligament,MCL)及后外侧角(posterior lateral corner,PLC)的损伤情况,并采用Spearman相关系数分析膝关节韧带损伤与胫骨平台骨折Schatzker分型及AO分型的相关性。结果Schatzker分型与AO分型(仅以关节外、部分关节内和完全关节内3种类型计算)对应分析结果显示,两者具有显著相关性(P=0.000)。Schatzker分型及AO分型与韧带损伤类型Spearman相关分析结果显示,Schatzker分型及AO分型与ACL、MCL及PLC损伤均呈显著相关性(r=-0.465、-0.639、0.756,P=0.013、0.000、0.000;r=-0.588、-0.420、0.532,P=0.001、0.026、0.004),但若AO分型以关节外、部分关节内和完全关节内3种类型计算,则仅与ACL损伤呈显著相关性(r=-0.465,P=0.013)。结论膝关节损伤时膝关节相关韧带之间有一定协同作用,故胫骨平台骨折多合并膝关节韧带损伤,且随着Schatzker分型与AO分型等级的增高,ACL、MCL及PLC损伤的可能性均增大。     

MR evaluation of the "arcuate" sign of posterolateral knee instability

OBJECTIVE: The purpose of this study was to evaluate associated knee injuries using MR imaging in patients with the "arcuate" sign, a term referring to avulsion fracture of the proximal fibula on conventional radiographs. MATERIAL AND METHODS: MR imaging of 18 cases (17 patients, both knees in one patient) with the arcuate sign on conventional radiographs was retrospectively interpreted to evaluate the associated meniscal, ligamentous, and bony injuries. In 12 cases, MR findings were correlated with surgical results. RESULTS: In all cases, avulsed bony fragments from the proximal pole of the fibula were attached to the fibular collateral ligament, the biceps femoris tendon, or both. Tear of the posterolateral capsule was seen in 12 cases (67%). Injury of the cruciate ligaments was noted in 16 cases (89%): injury to both the anterior cruciate ligament and posterior cruciate ligament was seen in nine cases (50%), injury to only the anterior cruciate ligament was seen in four, and injury to the posterior cruciate ligament only was noted in three. Bone bruises or gross fractures were seen in all cases: bone bruises on the anteromedial femoral condyle were noted in nine cases (50%) and were seen on the anteromedial tibial condyle in five cases (28%). Tear of the medial meniscus was seen in five cases (28%) and tear of the lateral meniscus in four cases (22%). Injury to the popliteus was seen in six cases (33%). Joint effusion was associated in all cases. CONCLUSION: MR imaging is useful for evaluation of associated soft-tissue injuries in patients with the arcuate sign on conventional radiographs. Avulsion injury to the proximal fibula is an important indicator of the internal derangement of the knee and for predicting the mechanism of an injury with varus stress. Cruciate ligament tear and bone bruises on the anteromedial condyle of the femur and tibia are common associated findings.     

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     

Usefulness of 99Tcm-MDP knee SPET for pre-arthroscopic evaluation of patients with internal derangements of the knee

The aim of this study was to ascertain whether knee SPET can localize lesion sites in patients with internal derangements of the knee. We performed knee SPET as a pre-arthroscopic examination in 63 consecutive patients. SPET imaging was performed with a triple-headed SPET camera 4 h after the injection of 99Tcm-methylene diphosphonate. Arthroscopic diagnoses were as follows: 28 medial meniscus injuries, 24 lateral meniscus injuries, 31 anterior cruciate ligament (ACL) injuries, three posterior cruciate ligament injuries and one medial collateral ligament injury. Of 30 patients with crescent-shaped increased activity at the medial tibial plateau, 22 had medial meniscus injuries (positive predictive value: PPV 73%); of 17 patients with crescent-shaped activity at the lateral tibial plateau, 13 had lateral meniscus injuries (PPV 76%). Of 18 patients with increased activity at ACL attachment sites (primary sign), 17 had ACL injuries (PPV 94%). Of 27 patients with increased activity at bone impaction sites of ACL injury (secondary sign), 22 had ACL injuries (PPV 81%). Of 32 patients who had either a primary or secondary sign, 26 had ACL injuries (PPV 81%). We conclude that knee SPET is very useful in the management of internal derangements of the knee, particularly in determining the need for arthroscopy by localizing lesion sites.     

Internal derangement of the knee after ipsilateral femoral shaft fracture: MR imaging findings

Objective. This study uses magnetic resonance (MR) imaging to delineate the types and frequencies of injuries seen in the knee after ipsilateral femoral shaft fracture. We also compare the results of the orthopedic knee examination with the MR findings. Design and patients. MR imaging of the ipsilateral knee was performed on 34 patients with closed femoral shaft fractures. Indications for knee MR imaging included knee pain at the time of fracture, soft tissue swelling or an effusion of the knee, or a positive knee examination under anesthesia. The patients had a mean age of 27 years and all were stabilized with intramedullary nails. Imaging was performed a mean time of 2.5 days after surgery. All patients had knee examinations done under anesthesia, and the MR results were compiled and compared with the clinical examinations. Results. Ninety-seven percent of patients demonstrated knee effusions. Twenty-seven percent of patients demonstrated meniscal tears, with the posterior horn of the medial meniscus most frequently torn. The medial collateral ligament was the most frequent site of ligamentous injury (38%) followed by the posterior cruciate ligament (21%). Fifty percent of patients had injuries of the extensor mechanism. Bone bruises were noted in 32% of patients. Articular cartilage injuries were confined to the patella in four cases. One occult tibial plateau fracture and one meniscocapsular separation were seen. Conclusions. There is a common incidence of both ligamentous and meniscal injury to the knee after ipsilateral femoral shaft fracture. MR imaging can be useful in assessing the extent of injury, and may reveal findings unsuspected after clinical examination of the knee.