Three-dimensional instability of the anterior cruciate deficient knee

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes.     

髌股关节不稳及髌前疼痛综合征

《The Knee》杂志主编、著名膝关节外科专家、英国伦敦Norfolk ＆ Norwich大学附属医院骨科Simon Donell教授，从事临床及基础研究近30年，有着很深的造诣。2005年11月，Donell教授应邀在上海交通大学附属第六人民医院举行的2005国际骨科研讨会上，就髌股关节不稳及髌前疼痛综合征做了专题演讲。与会者反应强烈，现予整理，与同道共享。     

Rehabilitation for anterior instability of the knee: preliminary report

Anterior instability of the knee and its associated rotatory components is recognized as a common disabling knee problem in athletes and nonathletes. The spectrum of anterior instability begins with injury to the anterior cruciate ligament as an isolated event or as part of an injury complex. Within the genera classification of anterior instability are straight, anteromedial, anterolateral, and combined. The type of instability is recognized in relation to the relative movement of the tibia on the femur and the rotational position of the tibia relative to the femur when an anteriorly directed force is applied to the tibia. The status of the static stabilizers of the knee dictates the type of instability. Treatment following anterior cruciate injury depends upon the extent of injury. Where significant disability and instability exist, reconstructive surgery utilizing intracapsular and/or extracapsular repairs can be performed. Rehabilitation begins at the time of injury and continues throughout life. The rehabilitation program should attempt to: 1) minimize risks of reinjury; 2) educate the patient; 3) reinforce stability with exercise based on biomechanical principles; 4) prevent or prolong the subsequent onset of degenerative changes; and 5) reinstate the previous performance level. J Orthop Sports Phys Ther 1982;3(3):121-128.     

When is surgery indicated in anterior knee instability?

Summary Rupture of the ACL may result in chronic anterior knee instability. However, in the majority of patients the secondary stabilizers of the joint such as collateral ligaments, menisci, and the capsule will compensate for this instability. We recommend surgical reconstruction of the acute rupture of the ACL only in the young, active athlete. Concomitant ruptures of capsuloligamentuous structures do not indicate surgical treatment: they may be treated by a plaster cast or a splint with good results. Chronic symptomatic anterior knee instability should first be treated by a vigorous muscle-training program. Surgery is performed only for those patients who cannot compensate for their instability after this rehabilitation program.

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Zusammenfassung Die Ruptur oder der Verlust des vorderen Kreuzbandes führt zur vorderen Knieinstabilität. Biomechanische und pathomechanische Erkenntnisse zeigen, daß die Funktionen des vorderen Kreuzbandes zumindest teilweise auch von Gelenkkapsel und Kollateralbändern übernommen werden. Deren Mitverletzung kann im Gegensatz zur Ruptur des vorderen Kreuzbandes konservativ ausgeheilt werden. So wird die Indikation zu operativen Maßnahmen bei frischen anterioren Knieinstabilitäten allein durch die Ruptur des vorderen Kreuzbandes bestimmt, nicht aber durch begleitende Verletzungen des kapsulären und/oder ligamentären Apparates. Bei veralteten vorderen Knieinstabilitäten ist es die nicht mögliche muskuläre Kompensation, die zu aktiven Maßnahmen im Sinne der Bandrekonstruktion zwingt.

     

Personal experiences in surgical treatment of chronic instability of the anterior knee joint

The results achieved with three different operative methods for the treatment of chronic anterior instabilities of the knee joint are presented. In 23 patients Trillat's modification of the O'Donoghue procedure was performed to reconstruct the medial collateral ligaments and the posterior capsule. Thirteen patients underwent reconstruction of the cruciate ligament with a free graft of the patellar ligament according to the Brückner method. In 37 patients the Brückner method was used for cruciate ligament replacement combined with lateral repair according to Ellison, and in some of these patients the posteromedial portion of the capsule was also reconstructed. Seventy-three patients (87.9% of all operated cases) were followed-up. The average observation period was 2.9 years and the mean age at the time of operation was 33.1 years. Major meniscal lesions were noted in 42 patients (57.5% of the cases). Twenty patients presented with combined instabilities or anteromedial grade II instabilities preoperatively. The majority of cases (53 patients) exhibited complex instabilities or anteromedial grade III instabilities preoperatively. At follow-up the Lachmann test was negative or trace-positive in 11 patients (48%) of group I, in 9 patients (69%) of group II, and in 34 patients (92%) of group III. Other stability tests, such as the pivot shift test and the drawer test, confirmed the superiority of group III. The overall results--considering both objective and subjective factors--showed good to excellent results in 12 patients of group I (52%), in 8 patients of group II (62%), and in 31 patients of group III (84%). We therefore conclude that combined and complex instabilities are indications for surgery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Arthroscopic semitendinosus-plasty with lateral extra-articular stabilization in anterior knee joint instability

Within the framework of a prospective study, 40 patients were examined postoperatively 12 months after their anterior cruciate ligament had been replaced by a doubled semitendinosus tendon arthroscopically combined with a lateral extra-articular procedure. "Second look" arthroscopy was possible in four cases. Evaluation was conducted according to the system of Müller and the Lysholm scoring system. According to the Müller system very good or good results were achieved in 97.5%; 95% of the patients achieved 91-100 points in the Lysholm scoring system. No substantial restrictions in the knee joint's range of movement were reported; there were also no other complications. The operative technique and the rehabilitation regimen are documented.     

The anterior cruciate ligament of the knee: An experimental study of its importance in rotatory knee instability

Summary The importance of the anterior cruciate ligament (ACL) in relation to valgus-varus and axial rotation stability in the knee joint was investigated. Mobility patterns were drawn from ten osteoligamentous preparations after successive transection of the two parts of the ACL and the medial (MCL) and lateral collateral ligaments (LCL). The knee joint remained grossly stable after partial injury of the ACL, while sectioning of the entire ACL caused an increase in internal rotation in the extended-semiflexed position. Combined lesions to the ACL and the MCL caused considerable valgus instability increasing with flexion, the joints remaining stable in extension. Moreover, marked anteromedial instability occurred, while only slight posteromedial instability was found. Combined lesions to the ACL and the LCL caused varus instability, worst in the semiflexed position, and a consistent pivot shift in applying a valgus torque in flexion was noted. Moreover, moderate posterolateral instability was found, at its maximum in the semiflexed position. External rotatory stability is secured primarily by the MCL, secondarily by the posterior medial capsule, and finally by the ACL. The existence of lateral pivot shift is proof of damage to the ACL.

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Zusammenfassung Die Bedeutung des vorderen Kreuzbandes (ACL) des menschlichen Kniegelenkes bezüglich der Varus-Valgus- and der axialen Rotationsinstabilität wurde untersucht. An osteoligamentären Kniegelenkpräparaten werden die Bewegungsabläufe nach schrittweiser Duchtrennung der beiden Anteile des ACL and des medialen (MCL) und lateralen (LCL) Seitenbandes aufgezeichnet. Das Kniegelenk blieb nach nur teilweiser Durchtrennung des ACL im wesentlichen stabil, während eine vollständige Durchtrennung eine zunehmende Innenrotation, sowohl bei voller Streckung als auch in halbgebeugter Stellung des Kniegelenkes zur Folge hatte. Kombinierte Verletzungen des ACL and des MCL riefen bei zunehmender Beugung eine beträchtliche Valgus-Instabilität hervor, wobei das Gelenk bei vol ler Streckung jedoch immer noch stabil war. Darüber hinaus konnte eine deutliche anteromediale — bei nur geringer posteromedialer — Rotationsinstabilität verzeichnet werden. Eine kombinierte Durchtrennung des ACL and des LCL erzeugte eine Varus-Instabilität, am deutlichsten in halbgebeugter Stellung des Gelenkes. Regelmaßig konnte ein Pivotshift-Phänomen ausgelöst werden. Hinzu kam eine mäßige posterolaterale Instabilität mit maximaler Ausprägung in halbgebeugter Stellung. Die außenrotatorische Stabilität des Kniegelenkes wird in erster Linie durch das MCL, danach durch die hintere Gelenkkapsel and erst zuletzt durch das ACL gewährleistet.

     

Anterolateral instability in the anterior cruciate ligament deficient knee. A cadaver study

Knee instability was evaluated in 13 normal osteoligamentous knee preparations after transection of the anterior cruciate ligament. Abduction-adduction rotation, coupled tibial translatory movement, and coupled tibial axial rotation were recorded continuously and simultaneously during flexion or extension while applying a well defined valgus directed moment and during extension while applying an anterior tibial force. As a result of the valgus-directed moment, an increase was found in abduction rotation, in coupled anterior tibial translation, and in coupled internal tibial axial rotation. Coupled rotatory and translatory instabilities were larger, and maximum instability was observed at a smaller knee angle during the extension movement than during the flexion movement. The pattern of the instability, excited as a result of the valgus moment, was different from the instability excited as a result of an anterior tibial force.     

Anterolateral instability in the anterior cruciate ligament deficient knee: A cadaver study

Knee instability was evaluated in 13 normal osteoligamentous knee preparations after transection of the anterior cruciate ligament. Abduction-adduction rotation, coupled tibial translatory movement, and coupled tibial axial rotation were recorded continuously and simultaneously during flexion or extension while applying a well defined valgus directed moment and during extension while applying an anterior tibial force. As a result of the valgus-directed moment, an increase was found in abduction rotation, in coupled anterior tibial translation, and in coupled internal tibial axial rotation. Coupled rotatory and translatory instabilities were larger, and maximum instability was observed at a smaller knee angle during the extension movement than during the flexion movement. The pattern of the instability, excited as a result of the valgus moment, was different from the instability excited as a result of an anterior tibial force.     

Long term results of late reconstruction for anterior or anteromedial instability of the knee

Forty-one patients who had had surgical repair for anterior or anteromedial instability of the knee were examined on average 3.7 years after the operation. Of these patients, 17 had been injured in sports activities, 11 in work accidents, 5 in traffic accidents and 8 during other activities. Twenty-six patients underwent intra-articular reconstruction of the anterior cruciate ligament where the Jones procedure was used, 7 with the HeyGroves procedure, and 2 by the Eriksson procedure. The remaining 6 patients were treated by transfer of the gracilis, semitendinosus tendon or fascia lata. During the operation, the medial collateral ligament was reefed in 4 knees and Mauck's reconstruction was performed on 4 knees. Medial meniscectomy was carried out in 9 patients. The results were evaluated using subjective, functional and objective criteria. The objective criteria included both clinical examination and stress radiography using a specially designed apparatus. Laxity of the medial collateral ligament and anterior drawer sign were recorded on radiographs, using the uninjured knee for comparison. The operation was estimated to have been successful subjectively (excellent or good) in 25 patients, functionally successful in 20 and objectively successful in 23 patients. In the personal opinion of 33 patients the knee improved. Meniscectomy and long follow-up time were found to cause a decrease in successful results. More arthritic changes appeared if meniscectomy had been performed. The patients returned to work within an average period of 3.7 months. In 7 cases the result was classified as functionally poor, and the knee required a subsequent operation.     

Measurement of anterior instability of the knee. A new apparatus for clinical testing

We have developed an apparatus to measure the anteroposterior stability of the knee to forces of up to 250 N, applied at 20 degrees of flexion. We measured anterior laxity at 200 N, anterior stiffness at 50 N and total laxity at +/- 200 N. A study of cadaveric knees revealed that the soft tissues surrounding the bones had a significant influence on the force-displacement curve, and emphasised that differences between injured and normal pairs of knees are much more important than the absolute values of the parameters. In 61 normal volunteers we found no significant left to right differences in anterior laxity at 200 N and anterior stiffness at 50 N. In 92 patients with unilateral anterior cruciate deficiency there were significant differences (p less than 0.0005) in anterior laxity, anterior stiffness and total laxity, the injured-normal differences averaging 6.7 mm, 1.3 N/mm, and 8.1 mm respectively.     

Pathogenesis of anterior knee pain syndrome and functional patellofemoral instability in the active young

Although it is universally accepted that patellofemoral malalignment is the main cause of anterior knee pain and functional patellar instability in the active young, the question remains to be answered: what is the mechanism whereby patellofemoral malalignment produces pain and instability? Currently, there are two theories to explain the origin of pain and instability in patients with patellofemoral malalignment: the neural theory and the mechanical theory. Both theories are not exclusive, but complementary. We believe it is the neural factor that precipitates the symptoms in patients with certain mechanical anomalies who also subject the knee to overuse.     

Prevention of knee instability. Experimental model for prosthetic anterior cruciate ligament.

Loss of the anterior cruciate ligament (ACL) in the dog results in a predictable type of arthritis. This condition can be prevented by successful prosthetic substitution of the anterior cruciate ligament (ACL). The condition is a practical model, and a sensitive index of success and failure for evaluation of prototype prostheses. Changes in the joint can be differentiated on the basis of cruciate insufficiency and reaction to the synthetic implant. The model was defined by replacing the ACL with a mesh or tape Dacron prosthesis in 16 Beagle dogs. Gait and anterior drawer sign are unreliable parameters of ACL insufficiency in dogs. At sacrifice up to 3 years postoperatively, 8 joints out of 32 joints were without arthritic changes. Arthritis developed in all joints in which the prosthesis elongated or broke. Failure always occurred intra-articularly at the mouth of a bone tunnel. Successes were inconsistent even with a single material and animal breed. The drillhole techniques used in ACL reconstructions are difficult to standardize. Variability in placement of the prosthesis is compounded by cutting action of bone edges. Porous mesh did not provide a lattice for true ligament regeneration through the joint. Fixation was not a problem in this series.     

Complex instability of the elbow

Injuries to the elbow are commonly encountered in orthopaedic practice. They range from low energy, simple isolated fractures, to high energy complex fracture dislocations with severe ligamentous disruption. Recognising the precise pattern of injury is critical in restoring elbow function and preventing chronic instability, pain and weakness. This article discusses the important osseous and ligamentous stabilisers of the elbow joint and provides management protocols for the common patterns of complex injury encountered by the practising surgeon.     

Acute uncomplicated anterior knee instability. 2-5 year follow-up of surgical treatment

A retrospective review of 158 acute anterior cruciate ligament injuries without additional ligamentous lesions was conducted. The follow-up study included 127 patients (80%), 109 of whom were personally examined 2-5 years after surgery. In the largest group proximal ruptures were found and treated with reinsertion. The other group had intraligamentary ruptures which were augmented with semitendinosus tendon. A modified Ellison procedure was routinely performed. Postoperative treatment was cast-free and included immediate physiotherapy using a functional brace. Examination at follow-up included Lysholm score, Tegner activity scale, instrumented testing with a KT-100 arthrometer and measurement of isometric leg muscle strength in four different positions. Among other clinical manoeuvres, the Lachman test and pivot shift testing were performed. No significant differences were found between the two groups in subjective evaluation, stability, consecutive meniscal lesions or patella symptoms. The average anterior dislocation difference at 89 N was 2 mm in both groups. Pivot shift was definitely absent in 88% of one group and 90% of the other. Almost no meniscal problems were noted, but 15% of the patients complained of patellofemoral pain.     

Posterior instability of the knee joint

Summary 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° to 90° 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° 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.

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Zusammenfassung An 25 osteo-ligamentären Kniepräparaten wurde der Einfluß des hinteren Kreuzbandes und der medialen und lateralen kapsulären Strukturen auf translatorische und gleichzeitige Rotationsinstabilität untersucht, wobei die jeweilige Instabilität kontinuierlich von 0° bis 90° Beugung unter konstanter Krafteinwirkung auf die Tibia registriert wurde. Isolierte Durchtrennung des hinteren Kreuzbandes (PCL) verstärkte die posteriore Verlagerung der Tibia unter Beugung des Gelenkes bis zu einem Maximum von 10 mm bei 90°. Wenn kombinierte Durchtrennungen der lateralen Kapsel hinzukamen, zeigte besonders die Popliteussehne (PT) eine beträchtliche sekundäre stabilisierende Funktion. Die posteriore Verlagerung der Tibia wurde verdoppelt, wenn alle lateralen Strukturen in die Verletzung miteinbezogen wurden. Durchtrennung des PCL und aller medialen kapsulären Strukturen führte zu einer beträchtlichen Zunahme der posterioren Verlagerung der Tibia unter Flexion des Gelenkes. Eine nennenswerte Zunahme der gleichzeitig auftretenden axialen Rotation der Tibia wurde nur nach kombinierter Durchtrennung der medialen oder lateralen Strukturen registriert. Ein umgekehrtes pivot shift-Zeichen wurde bei kombinierten lateralen Durchtrennungen nur hervorgerufen, wenn die PT miteinbezogen war. Selbst eine antero-mediale Subluxation wurde nach Durchtrennung der medialen Strukturen erzeugt. Ungeachtet der Verletzungstypen blieb das Präparat jedoch stabil gegen eine anteriore-posteriore Verschiebung unter Extension des Kniegelenkes, auch keine anteriore Verlagerung der Tibia konnte beobachtet werden.

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Aided by grant no. 12-4463 from Statens lægevidenskabelige Forskningsråd (The Danish National Research Council)     

Complex elbow instability

Complex elbow instability consists of dislocation of the ulnohumeral joint with a concomitant fracture of one or several of the bony stabilizers of the elbow, including the radial head, proximal ulna, coronoid process, or distal humerus. Recurrent instability is not often associated with simple dislocation, but an improperly managed complex dislocation may be a prelude to chronic, recurrent elbow instability. Complex instability is significantly more demanding to manage than simple instability. Radial head, coronoid, and olecranon fracture associated with dislocation each must be assessed and often require surgery. Long-term outcome with surgical management of complex elbow injuries is unknown. A few published series examine combinations of different injury patterns managed with various methods. Recently, however, several well-designed prospective outcome studies have evaluated management of several different individual fracture-dislocation patterns with a unified treatment algorithm. Fixation or replacement of injured bony elements, ligamentous repair, and hinged fixation may be used to successfully manage complex elbow instability.