Injuries of the Posterolateral Corner of the Knee

Abstract

The complex anatomy of the posterolateral corner of the knee is due largely to the evolutionary changes in the anatomic relationships of the fibular head, the popliteus tendon, and the biceps femoris muscle. Recent research has improved our understanding of the popliteus complex, particularly the role of the popliteofibular ligament. Biomechanical studies provide a scientific basis for clinical examination of the knee with suspected injury of the posterolateral corner. All grade-I and most moderate grade-II injuries of the posterolateral structures can be treated nonoperatively, but residual laxity may remain, especially in knees with grade-II injury. Acute grade-III isolated or combined injury of the posterolateral corner is best treated early, by direct repair, if possible, or else by augmentation or reconstruction of all injured ligaments. Chronic injury of the posterolateral corner, whether isolated or combined, is probably best treated by reconstruction of the posterolateral corner along with reconstruction of any coexisting cruciate ligament injury. Failure to diagnose and treat an injury of the posterolateral corner in a patient who has a known tear of the anterior or posterior cruciate ligament can result in failure of the reconstructed cruciate ligament. Injuries of the posterolateral corner of the knee are infrequent but can cause severe disability due to both instability and articular cartilage degeneration1-3. These injuries do not usually occur in isolation but are often associated with injury of the anterior or posterior cruciate ligament4,5. The diagnosis of subtle lesions of the posterolateral corner can be elusive unless there is a high degree of clinical suspicion for possible injury of this region. The consequence of missing a posterolateral injury in the presence of a known tear of the anterior or posterior cruciate ligament can be failure of the reconstructed cruciate ligament6-8. Recent studies have shed new light on the complex anatomy and functional mechanics of the posterolateral corner of the knee, and they provide a framework for improved diagnosis and treatment of these often disabling injuries. Anatomy The posterolateral corner of the knee, with its complicated and varying anatomy of static and dynamic stabilizers, is probably the least understood region of the knee; it was once considered the "dark side" of the knee9. The inconsistent terminology used to describe the structures in the posterolateral corner has added to the confusion10,11. This is underscored by the varying nomenclature applied to the popliteofibular ligament, which has been called the short external lateral ligament12, the popliteofibular fascicles13, the fibular origin of the popliteus14, the popliteus muscle with origin from the fibular head11, and the popliteofibular fibers15. In fact, because of an oversight, mention of this structure disappeared from standard anatomy texts and the orthopaedic literature during the middle of the twentieth century, only to be rediscovered recently16. Evolutionary and Developmental Anatomy To conceptualize the morphology of the posterolateral corner, an understanding of the evolutionary and developmental anatomy helps to explain some of the confusing structural relationships. The complex anatomy of the posterolateral corner of the knee is due largely to the evolutionary changes in the anatomic relationships among the fibular head, the popliteus tendon, and the biceps femoris muscle17. In paleontologic specimens dating back 360 million years, in extant lower vertebrates, and in early human embryonic development, both the fibula and the tibia articulate with the femur18-20. However, as the vertebrate knee evolved, the fibula and the attached lateral portion of the joint capsule moved distally to form a new capsular layer between the distal part of the femur and the proximal popliteus muscle, resulting in the popliteal hiatus and an intra-articular popliteus tendon. In early evolution, when the fibula articulated with the femur, the popliteus tendon inserted on the fibular head. With subsequent distal migration of the fibular head, the popliteus tendon acquired a femoral attachment while retaining its original fibular insertion17. There also was an evolutionary change in the location of the biceps femoris tendon attachment, from the lateral aspect of the capsule and the proximal part of the tibia to the fibula21. The major components of the posterolateral corner of the knee appear early in the course of human development. Between seven and eight weeks of embryonic development, the fibular head has completed its distal migration to reach a definitive location with respect to the proximal part of the tibia, and the lateral collateral ligament, popliteus tendon, and lateral meniscus are identifiable22-24. At eight weeks, the embryonic knee has assumed a shape similar to of the weeks the popliteofibular ligament can be during the of fibular with the attached popliteus tendon. the of development, the among the popliteus tendon, the lateral and the fibular head are in the knee are Anatomy The major structures of the posterolateral corner of the knee the the lateral collateral ligament, the popliteus complex of both dynamic components popliteus and static components popliteofibular ligament, and the middle of the lateral capsular ligament, the ligament, the ligament, the posterior of the lateral the lateral ligament, and the posterolateral part of the joint This anatomy can be In of the lateral structures of the knee as The most layer of the its anterior and the portion of the biceps and its The middle layer is by the but is by the ligaments. also the ligament. The and layer the lateral part of the joint This layer is a which the lateral collateral ligament and the ligament, and a which the ligament and the popliteal the ligament. The popliteofibular ligament is a of this anatomic in knee The ligament the posterolateral part of the capsule in of the the ligament it in and both it in of the posterolateral corner of the knee the The structure of the posterolateral aspect of the the basis of of and also in the posterolateral corner a fibular origin of the popliteus the popliteofibular in of the a ligament in and a ligament in In a of seven anatomic by the presence or of they the popliteus muscle with origin from the fibular head popliteofibular in a also the of the and by a lateral collateral ligament and a popliteus tendon in all knees and a popliteofibular ligament in and of knees to provide a of the complex anatomy and to a to the posterolateral used this in a of and it for and of injured components of the posterolateral corner of the The to the posterolateral corner of the knee from and of the popliteal The lateral is The articular the lateral collateral ligament and the lateral region of the This with the of the lateral to the lateral collateral The middle an to the posterior capsular from the posterior to the popliteus muscle, the and the joint to the fibular of the popliteal also the posterior capsular The posterolateral structures of the knee are from With from the posterior articular of the posterior and from the of the the popliteal the posterolateral part of the capsule and the external portion of the lateral The portion of the to the the portion of the lateral part of the The lateral articular from the and the portion of the lateral part of the capsule and the lateral collateral The knee complex an role in in the and are static and dynamic static joint changes in intra-articular and the and of knee and have also been in and The to joint and while the are are when high are in or when the knee is the of which are most of the articular are to or injury of the posterolateral structures not only knee but also to the of our of of the posterolateral corner of the knee to from studies in which changes in and have been and occur along the of the applied or and do With of ligament in the of the posterolateral structures in and external The lateral collateral ligament and the posterolateral part of the capsule and external of the tibia, with the a role a and the a role external The popliteus tendon external of the tibia during knee from to and it of the tibia during from to of the lateral collateral ligament and the posterolateral part of the capsule in posterolateral instability isolated of The posterolateral structures also as to posterior and isolated of the posterior cruciate ligament not or external also the static of the posterolateral structures to joint in knees and the of the lateral collateral ligament, the anterior and posterior cruciate and they the ligament complex of the ligament, popliteus tendon, ligament, and posterolateral part of the joint In the of from to the lateral collateral ligament and the ligament complex the structures and external of the tibia, while the posterior cruciate ligament was the structure posterior of the lateral collateral ligament or the ligament complex not posterior but combined in posterior the of of the lateral collateral ligament a to in all but when it was combined with of the ligament complex, the of and was of the posterior cruciate ligament in to in of the ligament complex external of but when it was combined with of the lateral collateral ligament, and external all and the posterior cruciate ligament was also there in posterior and all and external with of the posterior cruciate ligament not or external any knee the anterior cruciate ligament was along with the lateral collateral ligament and the ligament complex, and anterior and of of the anterior cruciate ligament or combined of the lateral collateral ligament and the ligament complex not of the the subsequent studies in isolated of the posterolateral structures external posterior and external of the posterolateral or external an in the posterior cruciate ligament between and of applied posterior on the tibia combined with external the in the posterior cruciate ligament all on the posterior cruciate ligament, it the in the anterior cruciate ligament between and of With of the in posterior of the ligament of the posterolateral structures posterior of the lateral but not of of the posterolateral structures and the posterior cruciate ligament posterior of both the and the lateral and of Recent research has also our understanding of the popliteus complex, particularly the popliteofibular ligament a was similar to by it the popliteofibular ligament. The of these studies the popliteofibular ligament may have been as part of the ligament complex in the external of the tibia was not by combined of the anterior cruciate ligament and the posterolateral corner, an from of who in external in the the static of the popliteus complex to knee by the lateral collateral ligament, the popliteofibular ligament, and the popliteus tendon attachment to the the structures in posterior and external and external also the popliteofibular ligament an role in posterior and and external the popliteofibular ligament a was only of the lateral collateral ligament, and it an to failure of with for the lateral collateral ligament. the of posterior on the popliteus complex and the lateral collateral ligament in knees and of the posterior cruciate ligament. these structures an role in posterior when the posterior cruciate ligament is all from the posterior part of the fibula the popliteofibular ligament the popliteus tendon to the with and in posterolateral knee the in anterior cruciate ligament in knees in which the posterolateral structures been with and they with and external and of of the lateral collateral ligament, popliteofibular ligament, and popliteus tendon. articular in knees with of and a of the combined of the posterolateral complex and the posterior cruciate ligament in joint isolated of the posterior cruciate ligament The of these studies provide a scientific basis for examination of suspected posterolateral injury of the isolated tear of the posterior cruciate ligament not or external but cause posterior of the tibia with knee The most of an injury is the posterior with the knee isolated tear of the lateral collateral ligament a to in is of knee be this of all posterolateral with an posterior cruciate ligament, in external and posterior of These in occur only to of the posterior cruciate are and are to these However, of all of the posterior cruciate ligament are and are to an a or external and to a posterior a injury of the posterolateral corner is combined with an injury of the posterior cruciate ligament, the and of a posterior cruciate ligament are high there is posterior and external all of knee isolated or combined posterolateral corner injury is for and external be and of and with the for the combined anterior cruciate ligament and posterolateral corner injury anterior and posterior external and probably There is as to whether the external of is for combined anterior cruciate ligament and posterolateral complex The also the clinical cruciate ligament are for failure in knees with posterolateral of injury of the posterolateral complex is of knees treated for ligament only isolated posterolateral and are the most of injury of the posterolateral corner of the posterolateral injury can result when a posterolateral is the proximal part of the tibia with the knee or This knee combined with a to the posterolateral can cause injury of the posterolateral corner in with injuries of ligaments. These a combined and external and a severe and a severe external possible of combined injury when the knee is and the tibia is and a is applied to the In this in the posterior cruciate ligament is with with because the posterolateral structures are to the applied The posterolateral complex is to the posterior cruciate ligament also be of the knee can also cause severe injury of the posterolateral corner There is on the of treated injuries of the posterolateral corner of the there are to on the of isolated injury of components of the posterolateral of the structures of the posterolateral corner are often as or whether there is or of the injuries are not associated with joint grade-II injuries are associated with to joint and grade-III injuries are usually associated with joint have used a of and to the of and used this to describe instability as moderate or severe have the of joint with a as to with a to with a or with a or who been treated for a grade-II or grade-III of the posterolateral At an of eight the the with a grade-II an or result as with and all residual However, the with a grade-III a and the on or of these also a tear of the anterior cruciate ligament or the posterior cruciate ligament, or and a lateral this be as a isolated posterolateral injury. of the with a grade-III injury on but patient with a grade-II injury In a in which the from to years, all of with a lateral ligament injury who instability treated by early a The in the of a possible injury of the posterolateral corner of the knee is to a with isolated injury of the posterolateral corner usually of in the posterolateral aspect of the knee, and some may have as of the was in of with isolated injury of the posterolateral corner in the of and in of with an injury by Recent by and and by on with posterolateral knee with combined of injury of of and of of with posterolateral injury may describe lateral and posterolateral may also have or from an injury of the have functional instability when the knee is in which the and of This instability may the knee during as and or and instability with or the posterolateral instability to describe posterior of the lateral can occur with an external in knees with laxity of the posterolateral corner. of posterolateral instability can occur severe or they can a posterolateral injury. Injuries of the posterolateral structures of the knee are associated with lesions and may be the of the The knee be for and with posterolateral corner injury the posterolateral joint with the fibular head or the joint in with or and in of in and in or in the region of the the suspicion of injury of the posterior cruciate or the posterolateral structures can be part of a of knee injuries have as a consequence of a of the a knee is a examination is and an may be with a suspected posterolateral corner injury be for and changes in may with a of the knee, and an by a or a may during the To the and instability of knee some may with a knee in the of in some with combined posterolateral and posterior cruciate be a to on the joint and the posterior part of the capsule are in with posterolateral knee injury may be to the instability posterolateral is to the functional of and is with the posterior be and of knee posterior is but is posterolateral injury be The of the posterior cruciate ligament is most by the posterior of knee but it can also be by for the posterior the posterior the the may be in to of knees and the dynamic posterior not all with posterior cruciate injury have a posterior on The of the anterior cruciate ligament can be by the of to diagnose injuries of the posterolateral corner of the knee have been To with a tear of the posterior cruciate ligament have any posterior while the posterolateral aspect of the knee is while they are in the or with the the tibia in a while they are external This can be with the patient or the may be for in the The be both and of knee because external but not an isolated injury of the posterolateral corner, external both injury of both the posterior cruciate ligament and the posterolateral corner. To used an to in the diagnosis of injuries of the posterolateral aspect of the on in external in knees both and of The of this of the tibia of the by or posterolateral corner external The of this of the posterior and external have with injury of the lateral collateral is with the knee to both and with of a posterior and external to the proximal part of the tibia and for posterolateral of the but not an isolated injury of the posterolateral corner of the knee, both combined posterior cruciate ligament and posterolateral injury. this is if there is a of when the knee is with The may injury of the posterior cruciate ligament and the posterolateral complex, but it may be in to of knees This by is used to diagnose posterolateral instability in the is by the by the and any in and external and on a of posterior in which the knee is and the is in to the and external of the lateral In a of knees the of this and to and there was not a the be and of knee to between isolated posterolateral corner injury and combined with a posterior cruciate ligament with a combined injury have an posterolateral both with an isolated posterolateral injury have a posterior this as a to for posterior and posterolateral injury. With the patient the the and knee to and the knee a or is when the tibia as the knee With posterior instability both but with posterolateral instability the lateral is back and is with a from while the patient with the knee and the on the part of the lateral femoral of the to the can be while the patient a and the most for the diagnosis of posterolateral knee injury the external and of and the and of the diagnosis of posterolateral they as the and the to clinical of a knee with posterolateral injury may of the lateral joint an of the fibular head, of the of the tibia, or a capsular which is an of the lateral aspect of the capsule from the the is usually considered of a tear of the anterior cruciate ligament, it also in with isolated posterolateral injury because the part of the capsule is and can cause of with posterolateral injury have changes with of the or lateral or with In some particularly knees for which it is to an can in the diagnosis of posterolateral corner in a and clinical of the structures of the posterolateral corner of the knee standard or In a of with a grade-III injury of structures of the posterolateral corner with an injury and with a a the fibular head and on all most of the components of the posterolateral aspect of the knee, as as and injuries of these be with by in of knees with combined injury of the posterolateral complex and the cruciate was the presence of a of the femoral on in all has also been to be in the diagnosis of injuries of the posterolateral corner of the and an of the lateral and popliteal hiatus in knees with an tear of the anterior cruciate ligament and knees with a structural lesions of the popliteus complex in of the injured and of the injured In a of knees with a grade-III injury of the posterolateral corner of the knee isolated posterolateral injury and combined was in lesions of structures in the lateral when it was with injuries have if only treatment been an of lateral joint laxity be as a a of in an injured knee with major capsular treatment of grade-I or injury of the posterolateral corner can have a In of seven with the treated with early a knee but the patient treated with in a residual treatment of the posterolateral corner of the knee has to functional who have posterolateral instability often have and associated may a degree of knee and this may isolated posterolateral or combined the mechanics are to the articular of all of the knee, may be of and muscle and improved in a of with combined posterolateral and cruciate ligament but is usually in for the treatment of lesions of the posterolateral corner of the knee can be as repair, and and Acute of the of the treatment of lesions of the posterolateral corner of the knee is is for posterolateral grade-III injuries of the posterolateral corner are direct anatomic of all injured structures weeks has the of the patient an the diagnosis of lateral injury and treatment of any associated or cruciate ligament ligament reconstruction is when a tear is and it is usually or reconstruction of the posterolateral The posterolateral corner of the knee can be a lateral or the injured structures has been but this a understanding of the anatomic relationships to be and and lateral capsular provide to the components of the posterolateral corner, but they it was to all in the structures be during the the biceps lateral collateral ligament, popliteus muscle and tendon, and popliteofibular of posterolateral injuries from to with of structures by direct or as In the the of injury direct repair, structures can be with tendon, biceps femoris tendon, or Chronic of the of the Chronic injury of the posterolateral corner of the knee usually a complex injury because of changes to and possible The of treatment of knee and a to or and a of the or of knee can be as are to the anatomy of the region or as are to the posterolateral corner by a grade-III injury of the posterolateral corner is associated with there is a combined the for a treatment of an isolated There is a of in the literature on the best of This is a of the of posterolateral the of the of in the and of and in In of and a lateral in the of be to a as an to on the lateral capsular structures are to be of both lower can in the In with posterolateral instability and of the lower the of the posterolateral corner is was a to in with combined cruciate and posterolateral knee injuries. and for an of anterior and distal of the attachment of the ligament complex lateral tendon, lateral collateral ligament, and popliteal these and as and This not injury to the popliteofibular ligament or the popliteus and it also the of the lateral collateral ligament and the popliteus tendon anterior and distal to which result in of these and the in with combined posterolateral and cruciate ligament injuries proximal of the posterolateral complex and cruciate ligament was from of and in the was with the knee in of and the lateral collateral ligament was its anatomic The posterolateral was functional in of the functional in and in an of and the posterolateral structures have and if or distal attachment is the These also used tendon or to the lateral collateral ligament, and they used tendon to the popliteus complex in with or of the posterolateral structures as who for an of a functional result and failure of the and of the biceps femoris tendon to the lateral femoral the of the biceps femoris muscle and an of the lateral collateral ligament. with posterolateral usually from combined cruciate ligament and posterolateral for an of this The of the in of and to to in associated with changes the knee joint and of also used the biceps along with reconstruction of the posterior cruciate ligament to treat combined injury of the posterolateral complex and the posterior cruciate ligament in At a of all or of the posterolateral instability as by the external in knees biceps be in external and but it by these static in or to a or laxity is not biceps not the popliteofibular ligament or popliteus tendon attachment to the tibia, both of which are and of the popliteus and lateral collateral the lateral femoral can the anatomic attachment This be in of when the popliteus and the popliteofibular ligament are the of this reconstruction may be with The of the femoral of the popliteus tendon and the lateral collateral ligament in the structures are in but and from injury and a posterolateral corner for the treatment of posterolateral of an of the or an tendon or to reconstruction of the popliteus tendon and The as a is a in the proximal part of the tibia and is proximal to the origin of the lateral collateral ligament on the femoral all of least a of laxity and or posterolateral instability to for an of to the the from an of to an of who an intra-articular an because of joint and residual and of these improved The was in the and laxity in of the This not reconstruction of the lateral collateral ligament or the popliteofibular ligament. a similar and all injured posterolateral structures be lateral collateral ligament with a tear can usually be reconstructed with a distally of biceps femoris tendon with or the popliteus complex, both the and the fibular of the popliteus tendon be With isolated injury of the or the fibular of the popliteus complex, the can a the lateral femoral distally a in the tibia or In both the and the fibular of the popliteus complex are a or tendon or can be With this the is in the lateral femoral the is distally and in the proximal of the tibia and fibula and used a similar a to the popliteus of the reconstruction of the attachment of the popliteus and the popliteofibular ligament with a tendon tendon can also be The is in the lateral femoral and its distal are in the and fibular isolated reconstruction of the popliteofibular ligament with a with treatment of posterolateral instability of the reconstruction of the lateral collateral ligament with a of the biceps femoris tendon. with treatment of posterolateral instability of the reconstructed the knees of who combined cruciate ligament and posterolateral used a with to only the lateral collateral ligament, and they also reconstruction of the anterior or posterior cruciate ligament. At an of laxity and or external of knee These because the was the lateral collateral ligament, it have as a functional for the and popliteofibular ligaments. is to whether this be in the associated with the treatment of posterolateral corner injuries injury during the or as and of knee failure of the and from used in the studies on the anatomy and of the posterolateral corner of the knee are to the treatment of these injuries. The of research of the posterolateral complex is for of the All grade-I and most moderate grade-II injuries of the posterolateral structures can be treated nonoperatively, but residual laxity may remain, especially in with a grade-II injury. Acute grade-III isolated or combined injury of the posterolateral corner of the knee is best treated early by direct if possible, or else by augmentation or reconstruction of all injured ligaments. Chronic whether isolated or combined with is probably best treated by reconstruction of the posterolateral corner along with reconstruction of any coexisting cruciate ligament injury. of have been to treat posterolateral but most have only With our understanding of the complex morphology of the posterolateral aspect of the knee, it anatomic with of and the best for However, of the of anatomic reconstruction the of clinical

The authors' abstract, as published at the source. Journal of Bone and Joint Surgery, 2001 · DOI ↗