The posterior cruciate ligament and rotatory knee instability. An experimental study

The importance of the posterior cruciate ligament in relation to valgus-varus and axial rotatory stability in the knee joint was investigated. Mobility patterns were drawn from 20 osteoligamentous preparations after successive transection of the posterior cruciate ligament (PCL), the medial and lateral collateral ligaments, and the posterior joint capsule. The knee joint remained grossly stable after isolated transection of the PCL, and further cutting of either one of the collateral ligaments or of the posterior capsule yielded no greater instability than one should expect from isolated cutting of each of these structures. The posterior cruciate ligament was the stabilizing factor in flexion and external rotation after injury to the lateral collateral ligament and the posterolateral capsule, and it restricted internal rotation after cutting of the medial cruciate ligament and the posteromedial capsule. Valgus instability was markedly increased during the whole range of movement when PCL was included in injury to the medial compartment ligaments, and when included in a lateral compartment injury a further varus instability was found, though only in the flexed or semiflexed knee. No hyperextension could be demonstrated after these injuries.     

Long term results of surgery for non-acute anteromedial rotatory instability of the knee.

Seventy-eight patients treated by extraarticular reconstruction including pes anserinus transfer for anteromedial rotatory instability of the knee were reinvestigated 16--47 months (mean 28) after operation. Function before and after operation was assessed by means of a knee rating score. Of these patients, 94 per cent showed a higher score after operation. Twenty per cent showed full recovery with no limitation of knee function whatsoever. The follow-up score was higher with preserved medial meniscus function than when this structure had been removed. When not initially torn, the medial meniscus tended to become involved with time. Mild laxity in extension, possibly indicative of a posterior cruciate injury previously underestimated or not observed, was found in 15 per cent of the patients. No correlation was found between late knee function and the interval between injury and operation or the interval between operation and follow-up examination. The long term results were good. Extraarticular reconstruction is thus indicated in cases of chronic rotatory instability of the anteromedial type. Routine meniscectomy is not recommended in these patients, however. Signs possibly indicating posterior cruciate ligament involvement should be carefully looked for, as even minor posterior cruciate injury, easily overlooked, may influence the late results.     

Long Term Results of Surgery for Non-Acute Anteromedial Rotatory Instability of the Knee

Seventy-eight patients treated by extraarticular reconstruction including pes anserinus transfer for anteromedial rotatory instability of the knee were reinvestigated 16-47 months (mean 28) after operation. Function before and after operation was assessed by means of a knee rating score. Of these patients, 94 per cent showed a higher score after operation. Twenty per cent showed full recovery with no limitation of knee function whatsoever. The follow-up score was higher with preserved medial meniscus function than when this structure had been removed. When not initially torn, the medial meniscus tended to become involved with time. Mild laxity in extension, possibly indicative of a posterior cruciate injury previously underestimated or not observed, was found in 15 per cent of the patients. No correlation was found between late knee function and the interval between injury and operation or the interval between operation and follow-up examination.

The long term results were good. Extraarticular reconstruction is thus indicated in cases of chronic rotatory instability of the anteromedial type. Routine meniscectomy is not recommended in these patients, however. Signs possibly indicating posterior cruciate ligament involvement should be carefully looked for, as even minor posterior cruciate injury, easily overlooked, may influence the late results.     

An irreducible knee dislocation: a case report

An 8-year-old man presented after sustaining an injury during a fall. A closed reduction attempt failed, and after several tests, an open reduction was performed. With posterolateral dislocation of the knee, there can be anterior cruciate ligament, posterior cruciate ligament, and medial collateral ligament disruption. At the 6-month (final) follow-up, the patient had no subjective pain or instability. With this type of injury, the approach can be conservative monitoring or repair of all of the ligaments. Because of the age and activity level of our patient, we opted for repair of the medial collateral ligament initially with the possibility of late anterior cruciate ligament and/or posterior cruciate ligament reconstruction.     

Evaluation of knee instability in acute ligamentous injuries

The stability on clinical examination (CE) and examination under anaesthesia (EUA) was evaluated in 350 consecutive acute knee injuries. Valgus instability in knees with a medial collateral tear was observed on CE in 62 and on EUA in 67 cases (p less than 0.05). The anterior drawer sign was positive in 55 patients on CE and in 110 patients on EUA (p less than 0.0001), the corresponding figures for the Lachman test were 66 and 126 respectively (p less than 0.0001). The pivot shift-test was positive in 13 cases on CE and in 87 under anaesthesia (p less than 0.0001). Fresh total tears of the anterior cruciate ligament (confirmed at arthrotomy, n = 79) were detected by the Lachman test in 48 per cent on CE and in 96 per cent on EUA. Of the nine fresh, total tears of the posterior cruciate ligament three were disclosed by the posterior drawer test on CE and all nine on EUA. Anteromedial rotatory instability was observed on CE in 10 patients and on EUA in 47 (p less than 0.0001). In these patients 41 medial collateral tears, 23 posteromedial capsular tears, 21 medial meniscus and 40 anterior cruciate lesions were found. On CE only one anterolateral rotatory instability was found, whereas EUA disclosed 9 cases. Posteromedial rotatory instability was not confirmed on CE, though on EUA four cases were found. CE and EUA detected 2 and 3 posterolateral instabilities respectively. In conclusion, the use of EUA with an adequate mode of stability evaluation in acute knee injuries is strongly advocated. Clinical examination is considered highly unreliable with many false negative findings.     

Therapeutische Möglichkeiten bei veralteten medialen Instabilitäten am Kniegelenk

Especially Grade II and III of chronic anteromedial rotatory instability of the knee should be treated by static and dynamic extraarticular procedures of the medial compartment. For the treatment of deficient anterior cruciate ligament we advise intra-articular replacement with a medial strip of the patella tendon, otherwise we expect meniscal degeneration, osteoarthritis and progressive instability. In patients with considerable instability and in young persons in addition to the cruciate ligament repair a distal iliotibial-band transfer is recommended to avoid attenuation of intra-intraarticular and capsular ligaments.     

Coordination of the anterior and posterior cruciate ligaments in constraining the varus–valgus and internal–external rotatory instability of the knee

 Tension along both cruciate ligaments was measured simultaneously under various loading conditions, and the interaction of these ligaments as constraints on knee instability was analyzed. Six fresh cadaveric knees were used. The attachments for both cruciate ligaments were detached from the femur and reattached to their original positions using metal plates equipped with 12 strain gauges. Each knee was moved under various loading conditions, and changes in tension along the cruciate ligaments were recorded simultaneously using the output of the strain gauges. Under varus torque, tension along the anterior cruciate ligament increased near full extension whereas that along the posterior cruciate ligament increased near 90° of flexion. Similar results were obtained under valgus torque. Under internal rotatory torque, a pattern similar to that under varus torque was also observed. Under external rotatory torque, no remarkable changes in tension were observed along either cruciate ligament. Thus, we conclude that both the anterior cruciate ligament and the posterior cruciate ligament cooperate to control varus–valgus and internal rotatory instabilities of the knee, and that the constraining function is transferred from the anterior cruciate ligament to the posterior cruciate ligament as the knee joint is flexed. Received: July 30, 2001 / Accepted: January 7, 2002     

Instability of knees with ligament lesions. Cadaver studies of the anterior cruciate ligament

We studied the importance of the two parts of the anterior cruciate ligament (ACL), the medial collateral ligament (MCL), and the posterior medial capsule (PMC) to translatory and spontaneous axial rotatory instability in 15 osteoligamentous knee preparations. Instability was recorded continuously from zero to 90 degrees of flexion with application of a constant force to the tibia. Isolated cutting of the ACL caused a moderate anterior translatory movement, which increased if the MCL was also cut. Transection also of the PMC resulted in an even larger range of anterior translatory movement. Combined lesions to the MCL and the PMC and the posterolateral part of the ACL did not cause such instability provided the anteromedial part of the ACL was intact. Application of a valgus moment to specimens with injured ACL and medial structures induced a spontaneous anteromedial subluxation of the tibia in a semiflexed position. When flexion was increased to 70-80 degrees, a sudden reduction was observed.     

Injuries to the posterolateral aspect of the knee accompanied by compression fracture of the anterior part of the medial tibial plateau

We present 12 cases of patients with injury to the posterolateral aspect of the knee accompanied by a compression fracture of the anterior part of the medial tibial plateau. There were 11 male patients and 1 female patient with an average age of 26 years (range, 17 to 44 years). There were 4 cases of posterolateral rotatory instability and 8 cases of straight lateral instability of the knee. The size of the compression fracture was classified into 2 types, small (8 cases) and large (4 cases). Although the mechanism of injury was considered to be hyperextension and varus force, the pattern of cruciate ligament injuries varied from case to case. The following 3 questions should be considered to determine which cruciate ligament is damaged: (1) Was the ipsilateral foot fixed to the ground? (2) Was forward inertia involved? (3) Was there a direct blow to the anteromedial aspect of the tibia or to the femur? Accompanied fractures of the medial tibial plateau were considered to have been compressed by the medial femoral condyle. The size of the accompanying compression fracture varied; 7 of 8 cases with a small-type fracture had posterior cruciate ligament injuries and 3 of 4 cases with a large-type fracture had anterior cruciate ligament injuries. The size of the fracture is determined by which point of the medial tibial plateau touched the medial femoral condyle. We propose that a compression fracture of the anterior part of the medial tibial plateau indicates a coexistent posterolateral aspect injury, and that especially a small compression fracture strongly suggests an accompanying posterior cruciate ligament injury, as well.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 6 (July-August), 2001: pp 642–647     

Posterior cruciate ligament recession.

Three cases of posterior cruciate ligament (PCL) laxity without posterolateral rotatory instability had magnetic resonance imaging scans that documented the structural continuity of the PCL. Tibial PCL recession was effective in eliminating symptomatic laxity in 1 case and lacked efficacy in the other 2 cases.     

Rotatory instability of cadaver knees after transection of collateral ligaments and capsule

Summary The importance of the medial and lateral compartment ligaments of the knee in relation to valgus-varus and axial rotation instability was investigated. Mobility patterns were drawn from 20 osteoligamentous knee preparations after successive transections of the structures. Cutting of the medial collateral ligament resulted only in slight valgus instability and modest anteromedial instability. When the medial posterior joint capsule was also cut, both types of instability increased, and moreover, the knee became posteromedially unstable. Cutting of the lateral collateral ligament produced only a little varus instability and anterolateral rotatory instability, but varus instability increased considerably when the posterior lateral capsule was also transected. In this latter situation, even marked posterolateral rotatory instability was found. Isolated transection of the medial or lateral collateral ligament did not cause any major valgus or varus instability, but when the posterior capsule was also transected, a considerable degree rotatory instability could be found even though the cruciate ligaments were intact.

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Zusammenfassung Die Bedeutung der medialen und lateralen Seitenbänder des Kniegelenkes in bezug auf die Valgus-Varus- und die axiale Rotationsstabilität wurde untersucht. An 20 osteoligamentären Kniegelenkpräparaten des Menschen wurden Bewegungsabläufe nach schrittweiser Durchtrennung dieser Strukturen aufgezeichnet. Die Durchtrennung des medialen Seitenbandes hat nur eine leichte Valgus-Instabilität und eine diskrete anteromediale Rotationsinstabilität zur Folge. Wenn darüber hinaus auch die posteromediale Gelenkkapsel durchtrennt wurde, verstärkten sich beide Formen der Instabilität, wobei die posteromediale Rotationsinstabilität besonders deutlich wurde. Nach Durchtrennung des lateralen Seitenbandes trat nur eine geringe Varus-und anterolaterale Instabilität auf. Wenn auch die hintere Gelenkkapsel durchtrennt wurde, nahm die Varus-Instabilitat beträchtlich zu and gleichzeitig zeigte sich auch eine deutliche posterolaterale Rotationsinstabilität. Eine isolierte Durchtrennung der medialen oder lateralen Seitenbänder führte zu keiner wesentlichen Varus- oder Valgus-Instabilität. Wurde jedoch gleichzeitig auch die hintere Kapsel durchtrennt, so trat eine erhebliche Rotationsinstabilität ein, selbst bei intakten Kreuzbändern.

     

Differential expression of integrin subunits in canine knee ligament fibroblasts.

A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.     

The posterior cruciate ligament and rotatory knee instability

Summary The importance of the posterior cruciate ligament in relation to valgus-varus and axial rotatory stability in the knee joint was investigated. Mobility patterns were drawn from 20 osteoligamentous preparations after successive transection of the posterior cruciate ligament (PCL), the medial and lateral collateral ligaments, and the posterior joint capsule. The knee joint remained grossly stable after isolated transection of the PCL, and further cutting of either one of the collateral ligaments or of the posterior capsule yielded no greater instability than one should expect from isolated cutting of each of these structures. The posterior cruciate ligament was the stabilizing factor in flexion and external rotation after injury to the lateral collateral ligament and the posterolateral capsule, and it restricted internal rotation after cutting of the medial cruciate ligament and the posteromedial capsule. Valgus instability was markedly increased during the whole range of movement when PCL was included in injury to the medial compartment ligaments, and when included in a lateral compartment injury a further varus instability was found, though only in the flexed or semiflexed knee. No hyperextension could be demonstrated after these injuries

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Zusammenfassung Der Einfluß des hinteren Kreuzbandes (PCL) in bezug auf Valgus-Varus- und axialer Rotationsinstabilität wurde untersucht. Anhand von osteoligamentären Präparaten wurden Bewegungsabläufe nach schrittweiser Durchtrennung des PCL, des MCL, des LCL und der posterioren Gelenkkapsel aufgezeichnet. Nach isolierter Durchtrennung des PCL blieb das Kniegelenk im großen und ganzen stabil, auch eine kombinierte Durchtrennung eines Kollateralligamentes oder der posterioren Kapsel erzeugte keine Instabilität, die sich von der nach isolierter Durchtrennung der erwähnten Strukturen unterscheiden ließ. Nach der Durchtrennung des LCL und der lateralen posterioren Kapsel zeigte sich das PCL als stabilisierender Faktor bei Flexion und Außenrotation, und bei Innenrotation nach Durchtrennung des MCL und der medialen posterioren Kapsel. Valgus-Instabilität wurde wesentlich verstärkt während des vollen Bewegungsausschlages, wenn das PCL bei Verletzung des medialen Bandapparates mitbetroffen war. Varus-Instabilität nahm von der semiflektierten Stellung an zu, wenn das PCL bei Verletzung des lateralen Bandapparates mitbetroffen war. Nach isolierter oder kombinierter Verletzung des PCL trat in keinem Fall eine Hyperextension auf.

     

Isolated lateral extra-articular tenodesis enhance better rotatory knee joint stability post-primary ACL repair: Four cases report and literature review

Introduction and importanceResidual rotatory instability has been reported to occur after primary anterior cruciate ligament reconstruction. The anterolateral ligament complex of the knee has gained attention for its role in rotational instability of the knee, especially in association with anterior cruciate ligament injuries. The role of an isolated lateral extra-articular tenodesis procedure among those patients presenting with residual rotatory instability after primary anterior cruciate ligament reconstruction has not been reported on.Case presentationFour patients (Tegner level 4) presenting with residual rotatory instability after primary anterior cruciate ligament reconstruction without signs of graft failure, underwent an isolated lateral extra-articular tenodesis with modified Lemaire procedure. Pre- and postoperative outcome scores were assessed. At one-year follow-up, all patients reported functional knee stability. Pivot shift tests were negative and postoperative Lysholm scores were increased with a mean of 19.75 points. Tegner scores equaled the preinjury level.Clinical discussionThis case report showed that our four patients where successfully treated with an isolated secondary modified Lemaire procedure for residual anterolateral rotatory instability after primary anterior cruciate ligament reconstruction.ConclusionAn isolated secondary lateral extra-articular tenodesis procedure can be a valuable treatment option for moderate active patients with residual rotatory instability after a primary anterior cruciate ligament reconstruction without signs of graft failure.     

Instability of knees with ligament lesions: Cadaver studies of the anterior cruciate ligament

We studied the importance of the two parts of the anterior cruciate ligament (ACL), the medial collateral ligament (MCL), and the posterior medial capsule (PMC) to translatory and spontaneous axial rotatory instability in 15 osteoligamentous knee preparations. Instability was recorded continuously from zero to 90 degrees of flexion with application of a constant force to the tibia. Isolated cutting of the ACL caused a moderate anterior translatory movement, which increased if the MCL was also cut. Transection also of the PMC resulted in an even larger range of anterior translatory movement. Combined lesions to the MCL and the PMC and the posterolateral part of the ACL did not cause such instability provided the anteromedial part of the ACL was intact.

Application of a valgus moment to specimens with injured ACL and medial structures induced a spontaneous anteromedial subluxation of the tibia in a semiflexed position. When flexion was increased to 70–80 degrees, a sudden reduction was observed     

Instability of knees with ligament lesions: Cadaver studies of the anterior cruciate ligament

We studied the importance of the two parts of the anterior cruciate ligament (ACL), the medial collateral ligament (MCL), and the posterior medial capsule (PMC) to translatory and spontaneous axial rotatory instability in 15 osteoligamentous knee preparations. Instability was recorded continuously from zero to 90 degrees of flexion with application of a constant force to the tibia. Isolated cutting of the ACL caused a moderate anterior translatory movement, which increased if the MCL was also cut. Transection also of the PMC resulted in an even larger range of anterior translatory movement. Combined lesions to the MCL and the PMC and the posterolateral part of the ACL did not cause such instability provided the anteromedial part of the ACL was intact.

Application of a valgus moment to specimens with injured ACL and medial structures induced a spontaneous anteromedial subluxation of the tibia in a semiflexed position. When flexion was increased to 70-80 degrees, a sudden reduction was observed     

Complex instability of the anterior knee

Complex knee instability involves the anterior cruciate ligament (ACL) and one or more major stabilizers of the knee [medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL)]. The medial side has a high healing potential and does not need operative treatment in most cases if ACL reconstruction is performed. Reconstruction of the medial ligament complex is indicated in gross instability of the medial meniscus fixation, dislocation of the MCL into the joint, and large dislocated bony avulsions. Injuries on the lateral side do not heal spontaneously and require acute operative treatment (first 2 weeks). Frank knee dislocations and gross multiligament injuries should be reduced acutely, and the integrity of the vascular structures must be examined closely. In a European multicenter study, operative treatment with reconstruction of both cruciate ligaments and functional rehabilitation gave better results than conservative treatment with immobilization of the joint.     

Relation of the fibular head sign to other signs of anterior cruciate ligament insufficiency. A follow-up letter to the editor.

The fibular head sign is a clinical finding that seems not to have been previously reported for the diagnosis of chronic anterior cruciate ligament insufficiency (ACLI) associated with lateral rotatory instability of the knee joint. The fibular head could be palpated as a prominent bony lump, felt subcutaneously in the posterior lateral corner of the popliteal fossa. In a prospective study of 20 patients with ACLI, the mean age of the patients (15 males, five females) at the time of assessment was 26 years (range, 18-57 years). The left knee was involved in 11 patients, the right knee in the remaining nine patients. All the patients sustained their knee ligament injury in sporting activities except one patient who was involved in a motor vehicular accident. The majority of the patients had instability-related symptoms for more than six months. After history taking, physical examination in the clinic, and examination under anesthesia, and arthroscopy in the operating room of all patients, it was determined that there were 13 ACL injuries, four posterior cruciate ligament (PCL) injuries, and three combined A/PCL injuries. All ACL injury patients had a prominent fibular head sign. Other associated signs included passive hyperextension of 10-20 degrees, and major anterolateral, and to a lesser degree a posterolateral, rotatory instability. The fibular head sign was negative in isolated posterior cruciate injuries and in combined A/PCL injuries.     

Posterior instability of the knee joint. An experimental study

We investigated the importance of the posterior cruciate ligament (PCL) and the medial and lateral compartmental structures for translatory and simultaneous axial rotatory instability in 25 osteoligamentous knee preparations. Instability was registered continuously from 0 degree to 90 degrees of flexion with application of a constant force to the tibia. Isolated transection of the PCL increased the posterior tibial displacement with flexion to a maximum of 10 mm at 90 degrees of flexion; when combined lesions to the lateral structures were included, the popliteal tendon (PT) in particular turned out to have a major secondary stabilizing function. The posterior tibial displacement in flexion was doubled when all lateral structures were included in the lesions. Transection of the PCL and all the medial structures led to a notable increment in posterior displacement increasing with flexion. Major increments in simultaneous tibial rotation were recorded only after combined lesions to either medial or lateral structures. A reverse pivot shift was provoked after combined lateral lesions when the PT was included. Even an anteromedial subluxation was released after lesions to the medial structures. Regardless of the type of lesion, the specimens remained stable concerning anterior-posterior displacement in extension. No changes in the anterior tibial displacement were observed.     

Restorative-reconstructive surgery of the bursal-ligamentous apparatus in chronic lateral instability of the knee joint

Restorative-reconstruction operations for treatment of chronic lateral instability of knee joint have been worked out. Chronic lateral anterior varus instability is eliminated by restoration of anatomy and biomechanics of anterior cruciate ligament and restructuring of peripheral part of the bursal-ligamentous apparatus by means of creation of fibular lateral ligament and 3 derotators (1 active and 2 passive ones). This operation is indicated as well in case of grave anterolateral instability. Instability of posterior types is treated by reconstruction of precise structure and function of posterior cruciate ligament and restructuring of peripheral part of medial or lateral sections of the bursal-ligamentous apparatus (it depends upon the nature of damage) by creation of active and passive derotators.