Disorders of the inert structures: Ligaments

53


Disorders of the inert structures


Ligaments



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Introduction


Ligamentous lesions at the knee are quite common. The joint is relatively uncovered by muscles, which makes it vulnerable to direct injury. Furthermore, the indirect forces acting on the knee have a large leverage, whereas the active and passive stabilizers of the joint have only a small leverage (Fig. 53.1) and thus give very inadequate protection.



Few other sports injuries cause as much concern as ligamentous lesions. Each contusion, even slight damage to the medial collateral or the coronary ligament, can cause serious trouble. Knee traumas should always be taken seriously because a neglected knee injury may lead not only to instability but also to the formation of adhesions.


There are great differences in attitudes towards the treatment regimes for the different injuries. The wide variety of traumas, the different degrees of damage and the combination of various lesions make it very difficult to compile a list of clear recommendations for treatment. In the classic textbooks, it is advised that minor ligamentous sprains are immobilized, whereas for serious or combined lesions, surgical intervention is generally recommended, especially when the patient is a young athlete or when development of later instability is feared.


We firmly believe that immobilization is never a good method. If there is a serious grade III lesion (see below) in a young athlete and instability is feared, the patient should be sent for surgery. If, for one reason or another, the patient is not treated surgically, early mobilization, deep transverse friction and functional treatment should be used. This treatment regime gives the needed physiological stimulus for quick and proper healing of the lesion and prevents the formation of adhesions, so often the cause of persistent trouble.1



Classification


Most accounts divide ligamentous injuries into three grades: grade I is slight overstretching with some microtears within the structure of the ligament; grade II is a severe sprain with a partial tear of the ligamentous fibres; and grade III implies a ligament which is completely torn across. In our opinion, this classification is rather arbitrary and, although it might be possible to distinguish a small lesion from a total rupture, the difference between grade I and grade II will always remain subjective.


Ligamentous injuries can also be classified according to which structure has been damaged. The commonest injuries are at the medial collateral and the anterior cruciate ligaments. Sometimes these occur together and in combination with a torn medial meniscus – the ‘unhappy triad’, or the triad of O’Donoghue2,3 – or in combination with a tear of the lateral meniscus.4 Lesions at the lateral collateral ligament and the posterior cruciate ligament are rare. In our experience, tears at the medial coronary ligament are very common; however, these are often misdiagnosed as medial collateral tears or meniscus lesions.


Sprained knees can also be classified according to the time that has elapsed since the causative accident. Here the terms acute, subacute and chronic are used:



This temporal division is important in choice of treatment (Table 53.1).




Diagnosis


Even in the era of arthroscopy, a clinical approach to ligamentous lesions continues to be vital.


In the acute stage, information obtained from the history and clinical examination enables the examiner to make the distinction between serious and mild lesions. If symptoms and signs warrant, the patient is then referred for further assessment by arthroscopy.5


In the chronic stage, only a thorough functional examination can lead to the diagnosis of ligamentous adhesions or estimate the degree of functional instability.



History


It is vital to obtain a very detailed history of the mechanism that has led to the injury, as summarized in Box 53.1, especially in acute sprains of the knee.




In long-standing cases, the current symptoms should be ascertained:




Examination


The functional examination described in Chapter 50 is carried out.


In acute cases, the ligamentous tests will sometimes be overshadowed by the capsular pattern of the traumatic arthritis, which makes it very difficult to estimate the degree of damage. In subacute and chronic cases, the capsular signs have largely subsided and the tests of ligamentous integrity become more informative. Sometimes, laxity is found during the routine examination, in which case instability tests are then carried out (see online chapter Disorders of the inert structures: ligamentous instability). Sometimes, it is not so much instability but rather pain and limitation of a non-capsular type that are detected; these indicate the formation of adhesions around the healed tissue.



Acute ligamentous lesions

In acute ligamentous lesions at the knee, the history will be what first indicates severity. A few hours after a serious sprain, the knee will start to hurt considerably and develop a distinct capsular pattern, protected by muscle spasm that makes it almost impossible to perform ligamentous tests. In order to distinguish between a serious injury and a less important lesion, a number of elements gained from the history may be of value (Table 53.2).



When the history indicates a serious lesion, especially if the patient is an athlete, it is wise to arrange arthroscopic evaluation. In contrast, in a more modest lesion, a conservative approach is indicated.



Chronic ligamentous lesions

Because the treatment is quite different, it is vital to differentiate between instability as the result of a total ligamentous rupture and chronic ligamentous adhesions leading to a ‘self-perpetuating inflammation’. Once again, history and clinical examination are the first approach to differentiate between these conditions and, in instability, to estimate its degree (Table 53.3).



Post-traumatic adhesions at the knee have the following signs and symptoms. The knee hurts locally after (vigorous) exertion or during the first few steps after it has been kept still for a while (e.g. in the morning or after sitting for a few hours). Sometimes slight swelling is also induced. Ordinary walking does not hurt. Clinical examination reveals slight limitation of movement, positive ligamentous tests and local tenderness.


Instability is characterized by a sensation of ‘giving way’ during unexpected movements under load. There may be accompanying pain and discomfort, sometimes lasting for a day or two. Additional instability tests will usually detect the type and degree of ligamentous insufficiency (see online chapter Disorders of the inert structures: ligamentous instability).


Treatment for a ‘chronic ligamentous sprain’, whether it is adhesion to nearby structures or self-perpetuating inflammation in the ligament itself, is relatively simple and as a rule gives quick and permanent results. Treatment of an unstable knee is more difficult and often requires surgical intervention.



Treatment: the principle of early mobilization


To most orthopaedic surgeons, ligamentous lesions of the knee, especially if they are grade III, require immobilization or surgical repair. The reasoning is purely anatomical: there is a rupture and the main medical task is to repair both ends, either by immobilization or by surgery. Our opinion tends more in the direction of mobilization and functional management.


Experimental studies over the past few decades have demonstrated that regeneration of injured connective tissue is significantly better with the application of continuous passive motion. Under functional load, the collagen fibres are oriented in a longitudinal direction and the mechanical properties are optimized.6 Therefore, functional conservative treatment is advised for all coronary ligament sprains and all isolated grade I, II or III sprains of the medial collateral ligament7 and posterior cruciate ligament and isolated grade I or II lesions of the anterior cruciate ligament.8 However, in combined lesions and in anterior cruciate ligament tears with a positive pivot shift phenomenon, surgery is the treatment of choice.9


Mobilization not only is the best promoter of ligamentous repair but also prevents ligamentous adhesions within or around the healing structure. Another advantage of early mobilization is the positive effect on muscle strength10 and proprioceptive reflexes,11 which ensures the active stability of the joint.


This conservative and functional approach to recent and isolated tears was first advocated by Cyriax12 and has recently received much support. Several studies have demonstrated that the non-operative management of an isolated medial collateral ligament injury, especially of grade I and II, is as good as, if not better than, a primary surgical approach.1318 The conservative treatment of grade III sprains of the medial collateral ligaments also gives results that are equally as good as the surgical approach but with significantly quicker rehabilitation.1921 Jones et al22 treated 24 high-school football players with an isolated grade III injury of the medial collateral ligament. They administered mobilization, using a regime of muscle strengthening and agility exercises. Knee stability was achieved in 22 cases, with an average recovery time of 29 days. The players returned to competitive sport after a mean of 34 days. Similar results were obtained in a long-term study of 21 grade III medial collateral ligament tears.23 The overall conclusion was that non-surgical treatment of a complete tear of the medial collateral ligament was extremely successful, provided there was no associated structural damage to the anterior cruciate ligament.


However, in advocating early mobilization, one common difficulty arises: the serious traumatic arthritis and the intense pain during the slightest movement are very strong impediments to early activity. As for ligamentous lesions at the ankle, this problem can be solved in two ways:



In long-standing and chronic ligamentous lesions, where scars have been allowed to form abnormal attachments in or around the healing tissues, the approach is to break the adhesions and remodel the fibrils in the functional longitudinal direction. This can be achieved by deep friction, sometimes with manipulation in addition.



Isolated sprains



Medial collateral ligament


The medial collateral ligament prevents valgus deviation of the knee and, through its posterior fibres, checks external rotation of the tibia.24 An understanding of this is of importance in the interpretation of clinical tests in a torn medial collateral ligament.25



Diagnosis


The medial collateral ligament is the most commonly injured ligamentous structure of the knee. The classic mechanism of injury is a forced valgus movement on a partly flexed and externally rotated knee,26 which typically occurs when a soccer or American football player receives a kick or blow at the outer side of the weight-bearing knee.27 The patient experiences a crack and feels sudden pain at the inner aspect of the knee. Most of the pain disappears fairly quickly and the sportsman or woman can probably return to the game or walk off the pitch. At first, the knee is not swollen and there is only slight disability. The real incapacity, with increasing swelling and pain, starts after a few hours. By the next day, the patient can hardly stand and can only hobble with assistance.


Clinical examination shows a hot and tender knee full of fluid. There is a gross articular pattern, with muscle spasm at the end of the range of movement: extension is probably 5–10° limited and flexion can be limited up to 90°. In this acute stage, it is impossible to perform proper ligamentous tests but the patient knows that the inner side of the knee was initially sprained, and localized tenderness is easily found at some point along the ligament.


The tear can be proximal, be related to the mid-portion of the ligament or be situated at the distal, tibial portion (Fig. 53.2). Mid-portion tears are the most common, but also the most disruptive, because they also involve the deeply situated meniscotibial and meniscofemoral portions of the ligament.28 In a proximal tear, it is wise to perform radiography to exclude avulsion of a bony fragment, which is an indication for surgical repair.29,30



The natural history of an injured medial collateral ligament is as follows. In the acute stage there is a traumatic arthritis, lasting about 2 weeks. Thereafter, during the subacute stage which lasts 4–6 weeks, the limitation of movement slowly diminishes. Although the joint remains warm at the inner side, the swelling goes down. Testing the ligament by applying strong valgus pressure (in 0° and in 30° of flexion) will elicit pain and, if the ligament has been totally ruptured (grade III), an excessive range will be detected. This is an indication for further stability testing.


After 2–3 months, the traumatic arthritis has totally subsided. At this stage, three situations are possible:



If an abnormal and adherent scar forms between the ligament and the surrounding tissues, any vigorous effort will sprain the impaired ligament afresh. In this case, the history is typical: the knee is quite adequate for ordinary walking and even running, but one small area at the inner side hurts when the patient takes vigorous exercise. The knee also feels stiff after it has been kept still for some time. Clinical examination shows a non-capsular pattern of limitation with, as a rule, painful full extension and limitation of flexion by 5–10°. External rotation and valgus strain hurt at the medial side of the knee. The other ligamentous tests are painless and instability cannot be detected. Resisted movements are strong and painless. There is no fluid or warmth, unless the patient is seen the day after some additional exertion. Tenderness should be sought along the medial collateral ligament. The usual localization is at the joint line. However, if a full range of movement is found after a former sprain but there is a clear history suggesting a chronic sprain and examination shows the medial collateral ligament to be at fault, tenderness is usually found at the femoral origin of the medial collateral ligament.




Treatment


All grade I and grade II sprains (partial tears), as well as isolated grade III sprains (complete tears) of the medial collateral ligament should be treated conservatively. Surgery is indicated only in combined lesions of medial collateral ligament and meniscus and/or anterior cruciate ligament.34


The technique chosen depends on the stage of the lesion, as summarized in Box 53.2. If the patient is seen during the first 24 hours after the accident, local infiltration with triamcinolone can be considered. Deep transverse friction in combination with early mobilization can be applied during the first 6 weeks following the accident. If the patient is seen after more than 6 weeks, the lesion must be considered as chronic and manipulation is given.




Acute stage


Infiltration and cold compression

Immediately after the accident, an ice compress is applied in order to prevent an excessive inflammatory reaction. As soon as the patient is seen, a small dose of triamcinolone (20 mg) can be injected at the site of the tear. Because this injection is extremely painful, a local anaesthetic must always be added.


During the next 24 hours, the patient remains in bed with an ice bag on the affected area. From the second day on, flexion is strongly encouraged, as is extension without weight bearing. During the first week, however, no attempt should be made to straighten the knee completely on walking; the medial collateral ligament is taut in extension and too much stretching at the point of injury would cause harm. On account of the anti-inflammatory effect of the triamcinolone, pain and swelling abate very quickly and normal gait is restored after 1–2 weeks. Walking and modest movement of the knee should be encouraged because they provide the best stimulus to normal healing and prevent the formation of adhesions. The patient can usually return to sports after 6 weeks.35 By that time, movements are of full range and ligamentous tests negative. It is wise to recommend a protective knee brace during the first few weeks of sporting activity, especially if the patient returns to contact sports.




Friction

Because a steroid injection, even a small amount, undoubtedly not only abates the excessive inflammation but also interferes in the union of the ruptured ligament, it is wise to use an alternative treatment modality if the patient is a young or professional athlete. Deep friction, applied from the first day, is an excellent alternative and gives identical results, providing the massage is given correctly.


Friction serves a double purpose: it prevents any fibrils from binding the ligament to bone and applies a positive stimulus to the healing connective tissue. As, in the acute stage, adhesions will not yet have formed, just 2 minutes of deep friction are required in both flexion and extension, though the preparatory phase of gentle massage, followed by slight superficial friction (which renders the ligament anaesthetized), may take up to 20 minutes. The patient is given this deep friction every day during the first week, after which the subacute stage is entered. If the massage is given adequately, the range of flexion increases dramatically during the first few days. The patient should be encouraged to walk and to move actively, although straightening the last 20° or flexing the last 60° must be avoided during the first week because these movements put too much longitudinal strain on the ligament.36 The joint can be protected with a partial mobile brace, the coronal straps of which prevent excessive valgus movement.37


Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on Disorders of the inert structures: Ligaments
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