Injuries to the posterior cruciate ligament and posterolateral structures of the knee

Although the incidence of injuries to the posterior cruciate ligament (PCL) is much lower than with the anterior cruciate, recent evidence suggests that deficiency of the PCL may be a much larger problem than originally thought, in the isolated case or in combination with posterolateral structures. Although advances have been made in understanding PCL injuries, the diagnosis and treatment of PCL insufficiency remain unclear. The natural history of a PCL-deficient knee is just beginning to be understood. Numerous methods have been reported for the surgical repair and reconstruction of the PCL, yielding less than optimal results in many cases. Controversy exists regarding the choice between conservative and surgical treatment in the isolated PCL injury. This article reviews the literature and summarizes the state of the art regarding the PCL and related posterolateral injuries, with an emphasis on anatomy, biomechanics, mechanism of injury, diagnosis and treatment Future directions in PCL research are proposed.     

Surgical treatment of ACL/PCL/ lateral-side knee injuries

Injury to the lateral knee structures is often accompanied by disruption of the posterolateral corner and cruciate ligaments. Failure to recognize and treat posterolateral pathologic laxity can result in persistent symptoms and failure of cruciate-ligament reconstruction efforts. Surgeons should proceed with early repair of the involved lateral and posterolateral structures when possible. Augmentation or reconstruction of the fibular collateral and popliteofibular ligaments is necessary if the existing tissues are inadequate. Late reconstruction is more challenging and requires careful attention to limb alignment. A proximal tibial osteotomy may be essential before ligament reconstruction surgery. Anatomic placement of high-strength grafts affords the best results. Improved surgical techniques, the use of allogeneic graft sources, and controlled postoperative knee range of motion reduce the risk of pathologic laxity and arthrofibrosis. Early surgical repair, augmentation, or reconstruction of the lateral structures combined with reconstruction of the cruciate ligaments provides the highest level of function.     

Operative treatment of posterolateral knee instability

Recognition of posterolateral rotatory instability (PLRI) and identification of the anatomic structures of theposterolateral region of the knee and their contribution to stability has occurred recently; therefore, surgical techniques to address these problems are evolving.     

The anatomy and biomechanics of thelateral aspect of the knee

The lateral and posterolateral aspects of the knee are complex and often confusing anatomic regions. The structures that comprise the lateral aspect of the knee are the lateral knee retinaculum, which is comprised of the iliopatellar band, and iliotibial tract. The complicated posterolateral corner is an integrated complex that includes the lateral collateral ligament, the popliteus tendon, the fabellofibular ligament, the arcuate ligament, the popliteofibular ligament, and the short lateral ligament. It is only recently that a much clearer understanding of the anatomic structures of the lateral and posterolateral aspects of the knee have been delineated. As a result a more accurate determination of the biomechanical contributions of each these structures has occurred. The lateral collateral ligament is the primary restraint to varus rotation at all degrees of knee flexion. The posterolateral structures, of which the popliteofibular ligament has been shown to play a major role, are also a primary restraint to external rotation. These same structures play a secondary role in the control of anterior and posterior translation of the knee. It is the hope that this improved understanding of the anatomy and biomechanics of the lateral and posterolateral aspects of the knee will translate into improved clinical management of the instabilities that are often so debilitating and clinical challenging.     

Treatment of acute and chronic injuries to the medial structures of the knee

The medial structures of the knee are critical to stability and function. Acting synergistically with the anterior cruciate ligament, the medial structures dynamically and statically stabilize the knee against valgus stress and anterior tibial translation. To fully comprehend mechanisms of injury and the resulting pathologies, it is important to have a thorough understanding of the underlying anatomy of the medial aspect of the knee. A systematic physical examination can delineate the extent and severity of the injury and distinguish between isolated and combined injuries. Controversy has surrounded the treatment of injury to the medial structures. The current trend, supported by research data, is to treat many of these injuries (particularly grade I and II and isolated grade III injuries) nonoperatively. Depending on the extent of the injury, however, and on which other structures are damaged, some patients will achieve the best functional result with primary repair, and other patients who were initially treated conservatively may ultimately require a reconstructive procedure.     

Anatomy and biomechanics of theposterior cruciate ligament and posterolateral corner

In this article, the current state of knowledge of the anatomy and biomechanics of the posterior cruciate ligament(PCL) and posterolateral corner (PLC) is discussed, as well as implications for the clinical management of PCL and PLC injuries. The PCL consists of 2 functional components, the anterolateral (AL) and posteromedial (PM) bundles based on their reciprocal tensioning patterns. Based on its larger ultimate load, stiffness, and cross sectional area, the AL bundle has been the focus of single bundle PCL reconstructions to date. The PLC of the knee is comprised primarily of the popliteus complex and lateral collateral ligament (LCL). A significant functional interaction exists between the PCL and PLC, as they work in conjunction to provide both posterior and rotatory knee stability. This article will discuss the interaction between these structures, including the effects of PCL and PLC deficiencies and the effects of factors such as muscle and axial loads on their function. The effects of several surgical variables affecting PCL and PLC reconstruction will also be addressed, including number and placement of tunnels, graft fixation, and associated injuries. Continued understanding of the structure and function of the PCL and PLC will result in the development and improvement of techniques for their reconstruction, as well as more consistent clinical approaches to these complex knee injuries.     

Management of combined anteriorcruciate ligament/posterior cruciate ligament/posterolateral complex injuries of the knee

The multiple ligament injured knee is a complex problem in orthopedic surgery. These injuries may present as acuteknee dislocations, and careful assessment of the extremity vascular status is essential because of the possibility of arterial and/or venous compromise. These complex injuries require a systematic approach to evaluation and treatment. Physical examination and imaging studies enable the surgeon to make a correct diagnosis and formulate a treatment plan. Arthroscopically assisted combined anterior cruciate ligament/ posterior cruciate ligament (ACL/PCL) reconstruction is a reproducible procedure. Knee stability is improved postoperatively when evaluated with knee ligament rating scales, arthrometer testing, and stress radiographic analysis. Posterolateral complex (PLC) injuries combined with ACL/PCL tears are best treated with primary repair as indicated combined with PCL reconstruction using a post of strong autograft (split biceps tendon, biceps tendon, semitendinosus), or allograft (Achilles tendon, bone-patellar tendon-bone) tissue. Surgical timing depends on the injured ligaments, vascular status of the extremity, reduction stability, and overall patient health. The use of allograft tissue is preferred because of the strength of these large grafts and the absence of donor site morbidity.     

Isometry of the lateral collateral and popliteofibular ligaments and techniques for reconstruction using a free semitendinosus tendon graft

Injuries to the lateral and posterolateral aspects of the knee are likely more common than appreciated. If theseinjuries are not recognized and treated, they may result in suboptimal results when treating injuries to the anterior cruciate ligament and posterior cruciate ligament. The treatment options for injuries to the lateral and posterolateral structures include primary repairs, primary repairs with augmentation, tightening of existing structures, and the creation of structural restraints from the lateral femoral epicondyle to either the posterolateral tibia or the fibular head. Reconstructive procedures to the fibular head offer advantages over those to the posterolateral tibia in that they are more optimally positioned to resist varus and posterolateral rotations, and tissue from the epicondyle to the posterior aspect to the fibular head maintains near isometry through a functional range of knee motion. A free semintendinosus tendon graft can be used to reconstruct the lateral collateral ligament and popliteofibular ligaments with minimal morbidity. This procedure can be used as an isolated procedure or in combination with other reconstructive procedures or primary repairs.     

MRI of knee ligament injury and reconstruction

Knee ligament instability may lead to meniscal and chondral damage, resulting in early osteoarthritis. Due to its superior soft tissue contrast and avoidance of harmful ionizing radiation, MRI has become the most important imaging modality for early recognition of structural defects of the knee joint. This review aims to the understanding of MRI appearances of knee ligament structures associated with knee instability, and to review the common patterns of altered knee mechanics that lead to ligament failure. Normal anatomy of the knee ligaments, pathologic conditions, and postsurgical appearances of the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and posterolateral corner are described. J. Magn. Reson. Imaging 2013;38:757–773 . © 2013 Wiley Periodicals, Inc .     

Treatment of nerve injuries in the multiple-ligament-injured knee

Dislocation of the knee is a serious and potentially limb-threatening injury. Associated ligamentous injuries,fractures, and vascular and nerve injuries are common. Prompt recognition of a knee dislocation and appropriate treatment of associated injuries is necessary to minimize the complications of this severe and potentially devastating injury. Peroneal nerve injury occurs in about 28% of knee dislocations and cases of multiple-ligament injury. Despite numerous advances in nerve repair techniques, the prognosis for nerve injuries after knee dislocation remains poor, with an overall recovery rate of 40%. This article provides a review of current recommendations for evaluation, treatment, and management of complications associated with nerve injury in knee dislocation, as well as areas for future study to improve prognosis and treatment.     

Complications in posterior cruciate ligament and posterolateral corner surgery

Posterior cruciate ligament (PCL) and posterolateral corner (PLC) injuries are complex injuries requiring specialized treatment. These technically demanding surgical procedures are performed less frequently than anterior cruciate ligament (ACL) reconstructions. Lack of experience in the evaluation and treatment of these injuries might lead to complications and suboptimal results. Complications associated with PCL and PLC surgeries include persistent laxity, osetonecrosis, neurovascular injury, compartment syndrome, motion loss, anterior knee pain, fractures, infection, and wound healing problems. A comprehensive preoperative evaluation, accurate diagnosis, well-planned and carefully executed surgical procedure, and supervised postoperative rehabilitation program might reduce the incidence of of complications associated with PCL and PLC surgical procedures.     

分析比较急性髌骨外侧脱位与膝关节多发韧带损伤后内侧髌股韧带损伤的特点

 目的 分析比较急性髌骨外侧脱位(lateral patellar dislocation,LPD)与膝关节多发韧带损伤(multiligament knee injuries,MLKIs)后内侧髌股韧带(medial patellofemoral ligament,MPFL)损伤的特点。方法 回顾性分析急性LPD 92例和MLKIs 83例患者的MRI资料,根据患者年龄分为青少年组(年龄≤18岁)84例和成人组(年龄＞18岁)91例,对LPD和MLKIs伴发MPFL损伤程度、部位进行统计学分析。结果 青少年LPD组50例中,MPFL部分撕裂20例,完全撕裂25例,未损伤5例;青少年MLKIs组34例患者中,MPFL部分撕裂9例,完全撕裂6例,未损伤19例;两组比较,差异有统计学意义(χ²=21.725,P<0.05)。青少年LPD组MPFL髌骨侧损伤19例,股骨侧14例,体部2例,多部位损伤10例;青少年MLKIs组MPFL髌骨侧损伤3例,股骨侧7例,多部位损伤5例;青少年LPD组和MLKIs组间MPFL髌骨侧、股骨侧、多部位损伤发生率差异均具有统计学意义(χ²=19.753,9.644,8.193,P值均小于0.01)。成人LPD组42例中,MPFL部分撕裂17例,完全撕裂19例,未损伤6例;成人MLKIs组49例中,MPFL部分撕裂13例,完全撕裂7例,未损伤29例;两组比较,差异有统计学意义(χ²=20.771,P<0.05)。成人LPD组MPFL髌骨侧损伤11例,股骨侧15例,体部2例,多部位损伤8例;成人MLKIs组MPFL髌骨侧损伤4例,股骨侧9例,多部位损伤7例;LPD组和MLKIs组间MPFL髌骨侧、股骨侧、多部位损伤发生率差异均具有统计学意义(χ²=14.773,12.777,6.822,P均<0.01)。结论 急性LPD比MLKIs更易导致MPFL损伤,MPFL髌骨侧损伤、股骨侧损伤和多部位损伤LPD也较MLKIs更常见。     

Posterolateral complex knee injuries: magnetic resonance imaging with surgical correlation

Purpose: To describe the magnetic resonance imaging (MRI) findings of injuries of the posterolateral aspect of the knee and to evaluate the diagnostic capabilities of MRI in the assessment of these injuries.

Material and Methods: The MRI studies of 14 patients (mean age 33 years) with trauma to the posterolateral aspect of the knee were retrospectively reviewed, and the imaging findings were correlated with those of surgery.

Results: In all patients, MRI showed an intact iliotibial (ITB) band. MRI showed injury to the biceps tendon in 11 (79%), the gastrocnemius tendon in 1 (7%), the popliteus tendon in 5 (36%), and the lateral collateral ligament (LCL) in 14 (100%) patients. Tear of the anterior cruciate ligament (ACL) was seen in 11 (79%) patients and tear of the posterior cruciate ligament (PCL) in 4 (29%) patients. With routine MRI, visualization of the popliteofibular or fabellofibular ligaments was incomplete. On MRI, the lateral meniscus and the medial meniscus were torn with equal frequency (n = 4; 29%). Osteochondral defects were seen in 5 (36%) cases and joint effusion in all 14 (100%) cases on MRI. Using surgical findings as the standard for diagnosis, MRI proved 86% accurate in the detection of injury to the ITB band, the biceps tendon (93%),, the gastrocnemius tendon (100%), the popliteus tendon (86%), the LCL (100%), the ACL (79%), the PCL (86%), the lateral meniscus (90%), the medial meniscus (82%), and the osteochondral structures (79%). Surgical correlation confirmed the MRI findings of joint effusion in all cases.

Conclusion: MRI is well suited for demonstrating the presence and extent of injuries of the major structures of the posterolateral complex of the knee, allowing characterization of the severity of injury.     

Treatment of combined posteriorcruciate ligament and posterolateral injuries of the knee

Treatment of combined posterior cruciate ligament/ posterolateral injuries requires a thorough knowledge of anatomy, injury mechanisms, and examination techniques. This articles reviews the classification and surgical treatment of these injuries.     

Anterior cruciate ligament tears for the primary care sports physician: what to know on the field and in the office

Anterior cruciate ligament (ACL) injuries are relatively common and can lead to knee dysfunction. The classic presentation is a non-contact twisting injury with an audible pop and the rapid onset of swelling. Prompt evaluation and diagnosis of ACL injuries are important. Acute treatment consists of cessation of the sporting activity, ice, compression, and elevation with evaluation by a physician familiar with ACL injuries and their management. The diagnosis is made with the use of patient history and physical examination as well as imaging studies. Radiographs may show evidence of a bony injury. MRI confirms the diagnosis and evaluates the knee for concomitant injuries to the cartilage, menisci and other knee ligaments. For active patients, operative treatment is often recommended while less-active patients may not require surgery. The goal of this review is to discuss the diagnosis of an ACL injury and provide clear management strategies for the primary-care sports medicine physician.