Seminar on Internal Derangements of knee

Internal Derangements of knee and its examination

Dr. Rajiv KumarP.G. D.orthSantosh medical college & Hospital, GZB1 Internal derangements of the knee (IDK)

It is a term used to cover a group of disorders involving disruption of the normal functioning of the ligaments or cartilages (menisci) of the knee joint.2ANATOMY OF KNEE JOINT

Bones & Articulations Largest joint in the body Synovial hinge type of a joint Mainly articulation of four bones ;femur, tibia, patella, fibulaEach articulation covered with hyaline cartilage; The primary articulation between Condyles of femur & tibia

3 LIGAMENTS Dense structures of connective tissue that fasten bone to bone & stabilise the knee. Inside the knee are two major ligaments-anterior & posterior cruciate ligaments

4Two other ligaments are located outside the knee Medial & Lateral collateral ligaments. They act to stabilise knee sideways motion.

The patellar tendon connects lower part of patella with upper part of tibia. Part of this tendon is used in Reconstructing a torn ACL

5MENISCI Two menisci are in each knee. Act as shock absorbers & also help in spreading weight .A meniscus is frequently torn at the same time as ACL tears during injury.

6ClassificationThe following disorders may be met with:-Sprain or tear of the medial collateral ligament.Sprain or tear of the lateral collateral ligament.Partial or complete rupture of the anterior cruciate ligament.Rupture of the posterior cruciate ligament.Tear of the medial semilunar cartilage. This may take the form of a longitudinal spilt (bucket handle tear), or an anterior or posterior horn tear.Tear of the lateral semilunar cartilage. The same variations occur as with a medial cartilage tear.Tear of a degenerate meniscus.Cyst of a semilunar cartilage, usually the lateral.THE COMMONEST DERANGEMENT IS MEDIAL COLLATERAL LIGAMENT INJURY FOLLOWED BY MEDIAL MENISCUS INJURY AND ACL

7AetiologyPhysical trauma is the cause of the vast majority of IDKs. The majority of acute knee injuries result from a valgus and/or twisting strain. Most commonly, they involve the medial joint structures and the anterior cruciate ligament.The type of physical trauma causing IDK may be a sports injury, a road traffic accident or an occupational stress; by far the most common at the present time is a sports injury.8The most frequent cause of damage to the medial collateral ligament is forced valgus injury to the kneeLateral collateral ligament injuries are much less common, as varus stress to the knee occurs much less frequently than valgus stress.Anterior cruciate ligament injury occurs from forced valgus stress to the fully extended knee. Posterior cruciate ligament injury is liable to occur in motor car accidents caused by high velocity trauma, with posterior dislocation of the tibia on a flexed knee, as in a dashboard injury.9Meniscus tears occur when substantial rotational stresses are applied to the flexed knee. They are particularly common in footballers, when the player is tackled from the side; they are also liable to occur in other sports such as hockey, tennis, badminton.10MEDIAL COLLATERAL LIGAMENT Anatomy: MCL is composed of superficial & deep portions

superficial MCLanatomically this is the middle layer of the Medial compartmentproximal attachment: posterior aspect of medial femoral condyle. distal attachment: metaphyseal region of the tibia, upto 4-5 cm distal to the joint, lying under the pes anserinus

11function: provides primary restraint to valgus stress at the knee providing from > 60-70% of restraining force depending on knee flexion angle: at 25 of flexion, the MCL provides 78% of the support to valgus stress;

at 5 of flexion, it contributes 57% of the support against valgus stress; superficial ligament can be divided into anterior & posterior portions;

anterior fibers of superficial portion ofligament appear to tighten with knee flexionof 70 to 105 deg;

posterior fibers form the posterior obliqueligament Deep MCL anatomically this is the third (deep) layer of the medial compartment which in many cases will beseparated from the superficial MCL (layer II) by a bursa (which allows sliding of the tissues during flexion) divided into meniscofemoral and meniscotibial ligaments inserts directly into edge of tibial plateau & meniscus firmly attaches to the meniscus but does not provide significant resistance to valgus force14 Examination Findings: valgus stress testclinical findings may not match complete injury; it is helpful to anchor the thigh on the table with the knee and leg off the edge of the table; opening of 5-8 mm compared to opposite knee may indicate complete tear; determine the point of maximal tenderness to determine whether the tear has occurred proximally, mid-substance, or distally; 15 instability in slight flexion:anterior portion of the medial capsule is primary stabilizer at 30 deg of flexion;hence at 30 flexion, testing is specific for just MCL; instability in extension: posterior portion of the MCL, posterior oblique ligament, ACL, medial portionof posterior capsule & possibly PCL;

location of tears:

- femoral tear: - mid substance tear:

- tibial tear:

INVESIGATIONS - X-ray:

- MRI: 17combined ACL/ MCL injuries

with concomitant MCL and ACL tears, most surgeons now recommend ACL reconstruction after the valgus stability has returned

the one exception might be the MCL tear arising from the tibial insertionLateral collateral ligamentDiscussion

lateral collateral ligament is primary restraint to varusangulation

LCL also acts to resist internal rotation forces

cutting of LCL in combination with either anterior orPCL results in large increase in varus opening

19varus stress test

testing with extension:LCL resists approximately 55 % of applied load at full extension

cruciate ligaments (primarily ACL) resist approx 25% of moment atfull extension

significant instability in full extension indicates complete LCL tear aswell as a tear of either the ACL or PCL ligament

note that LCL instability in extension which occurs with peronealpalsy is a knee dislocation until proven otherwise

testing with 30 deg flexion:

role of LCL increases with joint flexion, as posterolateral structuresbecome lax

with joint flexion,resistance by ACL decreases, but large forces arefound in PCL at 90 degrees of flexion

LCL is primary restraint to varus stress at 5* & 25*Flexion

lateral capsular structure provide secondary support

iliotibial band & popliteus muscles have dynamic stabilizing role

Surgical Reconstruction:allograft reconstruction:With chronic posterolateral injury, Achilles tendon allograft may be indicated

At the level of Gerdy's tubercle, a bone tunnel is created in the posterolateral tibia, just medial to the fibular head

Attachment of the IT band to the intermuscular septum may have to be freed for optimal exposure22FUNCTIONAL ANATOMY OF ACLThe ACL is a broad ligament joining the anterior tibial plateau to the posterior intercondylor notch.The tibial attachment is to a facet, in front of & lateral to anterior tibial spine.Femoral attachment is high on the posterior aspect of the lateral wall of the intercondylar notch.It is composed of multiple non-parellel fibres which though not anatomically separate, act as three distinct bundles i.e. anteromedial, posterolateral & intermediate. 23 FUNCTIONS The biomechanical function of the ACL is complex for it provides both mechanical stability & proprioceptive feedback to the knee.In its stabilising role it has four main functions; 1.Restrains anterior translation of tibia. 2.Prevents hyperextention of knee. 3.Acts as a secondary stabiliser to valgus stress, reinforcing medial collateral ligament. 24ACL deficiency causes failure of this screw-homemechanism,resulting in subluxation of tibia on the femur.

This critical function in the range of 0-30* is important formovements such as side-stepping & pivotting.

25 T he ligament is surrounded by synovium,thus making it extra synovial.

Blood supplyprimarily from the middle genicular Artery which pierces the posterior capsule & enters the intercondylar notch near femoral attachment.Additional supply comes from retropatellar pad of fat via the inferior medial & lateral geniculate arteries.

NERVE SUPPLY: Posterior articular nerve 26Rupture of ACL causes significant short term & long term disability.

With each episode of instability there is subluxation of tibia on the femur, causing stretching of the enveloping ligaments & abnormal shear stress on the menisci & on the articular cartilage.

Delay in the diagnosis & treatment gives rise to increased intrarticular damage as well as the stretching of secondary capsular ligaments. 27The long term outlook for an ACL deficient knee is for the development of significant osteoarthrosis. CAUSES OF ACL RUPTURE 1.Most common cause of ACL rupture is traumatic force applied to the knee in a twisting moment. This can occur with direct or indirect force. 2.Patients with narrow intercondylar notch are more prone to rupture their ACL. 28 3.Patients with genu recurvatum tend to be more likely to rupture their ACL & are more difficult to treat.

4.Patients with generalised ligamentous disorder.

5.Familial predisposition has been found to play a role in some patients especially those who sustain bilateral ACL tears.29Classical historyBegins with a non contact deceleration, jumping or cutting action. Other mechanisms of injury include external forces applied to the knee. The patient often describes the knee as having been hyperextended or popping out of the joint & then reducing. A pop is being frequently heard or felt. The patient usually has fallen to the ground & is not immediately able to get up. Resumption of activity is not possible & walking is often difficult. Within a few hours knee swells & aspiration of joint reveals haemarthosis. In this scenario ,the likelihood of ACL injury is greater than 70%. 30ExaminationANTERIOR DRAWER TEST With the knee flexed to 90*, verification of relaxation of hamstrings is confirmed. With foot stabilised & in neutral rotation, a firm but gentle grip on the proximal tibia is achieved.

31An anterior force is applied to the proximal tibia with a gentle to & fro motion to assess for increased translation compared to contralateral knee. 5mm is the upper limit of anterior tibial displacement normally.

32Drawer sign is minimal in isolated ACL rupture. Abnormal displacement >5mm is permitted by loss of restraint by ACL & more so when associated with insufficiency of medial CL or capsular ligament.

When an intact PCL is rendered very taut by forcible internal rotation of tibia, it stabilises the knee to the extent that the anterior drawer sign is negated.

If internal rotation of tibia does not lessen the anterior drawer sign, the PCL is also insufficient.33LACHMANS TESTOne hand secures and stabilises the distal femur while the other hand grasps the proximal tibia.A gentle anterior translation force is applied to the proximal tibia.

34LACHMANS TEST CONTDExaminer assesses for a firm/solid or soft endpoint.Stabilisation of right knee during an examination under anaesthesia.

35 Application of anterior tibial translation force with significant ant. translation of the tibia on the femur in an ACL deficient knee.When veiwed from side, a silhoutte of the inferior pole of patella,patellar tendon & proximal tibia shows slight concavity.Disruption of ACL & anterior translation of tibia obliterates the patellar tendon slope.

36 PIVOT SHIFT TESTPatient rotated 20* from supine towards the unaffected side. With slight distal traction on the leg,a valgus & internal rotation force is applied to the extended knee.

37With maintainance of force noted above,the knee is flexed past 30*

38Pivot shift in an ACL deficient knee,in the initial stages of knee flexion,the tibia will be anterolaterally subluxed on the distal femur with application of valgus & internal rotation at the knee.

39With further flexion of knee(past 30*) the illiotibial band goes from an extendor to flexor of knee & tibial anterolateral subluxation reduces back in place.

40Isolated tear produces only small subluxation, greater subluxation occurs when lateral capsular complex or semimembranosus corner also is deficient.DISADVANTAGES:Severe valgus instability may make this test difficult to do because of lack of medial support. FLEXION ROTATION DRAWER TEST Combines anterior drawer & pivot shift test.Mild degree of valgus stress & anterior pressure on upper calf are applied to elicit the positive test.41ARTHOSCOPY:Acute complete tear most often found through the midportion & may appear ragged.Less often it is torn at its either end.

42Roentgenographic studies:Plain roen.often are normal, however,a tibial eminence fracture indicates an avulsion of the tibial attachment of ACL.MRI is the most helpful.

43MRI FINDINGS:1.PRIMARY SIGNS: Nonvisualisation Disruption of the substance of ACL by increased abnormal signal intensity Abrupt angulation Wavy appearance Abnormal ACL axis.2.SECONDARY SIGNS:Segonds fractureosteochondral fracture Anterior translation of tibiaPivot shiftBone bruises.44

45 LEFT-Normal ACL in axial plane; RIGHT: Non-visualisation as primary sign of ACL tear with ill-defined edema & haemorhage in the usual location of the ACL in the I/C NOTCH.

46ACL tear with non-linearity of ligament; mild angulated ACL

segonds fracture in a patient with ACL tear.

47Anterior translation of tibia as a secondary sign of ACL tear. Tangential line to the posterior margin of tibia passes through the posterior horn of lateral Meniscus (uncovered meniscal sign).In normal knee, this line passes posterior to the meniscus.

48Before any surgical Rx, patient is sent to physical therapy.

Resolution of inflammation & return of full motion reduce the incidence of postoperative stiffness

It usually takes 2 to 3 weeks from the time of injury to achieve full range of motion.

It is also recommended that some ligament injuries be braced & allowed to heal prior to ACL surgery. 49Surgical optionsRepair of ACL either isolated or with augmentation.

Reconstruction with either autograft, allograft or syntheticsp

Primary repair of the ACL is no longer recommended because repaired ACL have generally been shown to fall overtime.

The torn ACL is generally replaced by a substitute graft made of tendon.The grafts commonly used:PATELLAR TENDON AUTOGRAFT;HAMSTRING TENDON;QUADRICEPS TENDON50

51

52POSTERIOR CRUCIATE LIGAMENT:ANATOMY Intra-articular but extrasynovial, static stabiliser of knee:

composed of two major parts:Large anterior part that forms the bulk of the ligament & a smaller portion that runs obliquely to the back of tibia.

PCL is attached proximally to the posterior part of the latral surface of the medial condyle.The tibial attachment is to a depression behind & below the intra-articular portion of tibia with a slip usually blending with the posterior horn of the latral meniscus.53Origin & insertion sites of posterior cruciate ligament:

54

Arthroscopic view of PCL:

56Biomechanics: Progressive tightening of the PCL occurs during internal rotation of tibia with the knee in either flexion or full extension.

Also in full extension the PCL allows only minimal abduction or adduction widening of the knee despite complete removal of accessory supports;the extensor retinaculum, capsular ligaments, collateral ligaments & posterior capsule.

This fact emphasis the importance of the PCL as the basic stabiliser of the knee, while the ACL & collateral ligaments augment its stabilising effect. 57Functions

provides restraint against hyperextension,

against posterior displacement of tibia in flexed knee,

internal rotation of the tibia &

valgus/varus angulation-particularly in extended knee.58 ACUTE TEAR: Requires much more force than to tear ACL.

Following ways:

1.Severe rotational injury; an external rotation-valgus injury or an internal rotation-varus injury produces tear of PCL assoc. with disruption of MCL or LCL.The PCL is interupted at its midportion or at its femoral attachment.

2.Hyperextension injury: Tibial attachment is avulsed usually

3.Direct trauma to upper tibia while the knee is flexed-Dashboard injury.

4.Complete dislocation of knee. CLINICAL PICTURE:

History of severe trauma is elicited.

Degree of both immediate pain & inability to bear weight on the injured knee is highly variable.

These are more pronounced when capsule is intact & haemarthrosis is confined within the joint.

They may be minimal when the posterior capsule is disrupted & blood escapes from the joint.

60Objective findings are:

tenderness in the popliteal fossa;swelling in allmost all cases.Posterior drawer sign in allmost 60% of cases.

POSTERIOR DRAWER TEST

With knee flexed to approx. 90*, verification of complete relaxation of hamstrings is confirmed by palpation .62With foot in neutral rotation & stabilised, a firm but gentle posterior translation force is applied to proximal tibia.Initial starting point for a posterior drawer test(foot in NR, knee flexed to 90*)

63Application of posterior translation force results in posterior subluxation of tibia on the femur in a patient with PCL deficient knee.

64TIBIAL BACK DROP TESTIn this test, the examiner compares the prominence of the proximal tibiato the femoral condyles with the knee flexed to 80*.In a PCL deficient knee, the knee will be posteriorly subluxed due to gravity.

65In a normal knee at 80* the tibial plateau is located approximately 1cm anterior to the femoral condyles

66TIBIAL BACK DROP TEST IN A PCL DEFICIENT LEFT KNEE

NORMAL CONTRALATERAL RIGHT KNEE.

67QUADRICEPS ACTIVE TEST:It is performed with the knee flexed to 80deg & in neutral rotation.Its starting point is in effect the tibial drop back test.

68From its initial relaxed position, the patient is asked, to contract Quadriceps muscle (straighten out his leg without extending his knee) while examiner applies counter pressure against the ankle.

69Quadriceps pulls anteriorly through the tibial tubercle to reduce any posterior translation in the knee.

Reduction of a posteriorly subluxed tibia with Quadriceps contration in a PCL deficient knee.

70Contraction of the quadriceps muscle in a knee with a PCL deficiency results in an anterior shift of >2mm.ROENGENOGRAPHIC FINDINGS:Plain radiographs usually normal.Stress radiography assists in the diagnosis of PCL injuries.Increased posterior translation of 8mm or more in stress roeng.is indication of complete rupture.A contrast arthogram may reveal evidence of ligament disruption.Arthroscopic evaluation should be done to assess the damage to both the cruciates & to define additional lesions.72MRI studies are more reliable for diagnosis of PCL tears than ACL tears.

73RECONSTRUCTION OF PCL:Can be done by open or Arthroscopic technique;arthroscopic technique is prefered.Various grafts used are : (1).Patellar tendon graft. (2).Bone-patellar tendon-bone graft. (3).Tendo-achillis bone graft. (4).Illiotibial band. (5).Medial head of gastrocnemius tendon. (6).Hamstring tendon. (7).Lateral meniscus.74MENISCUS INJURY75AnatomyThe menisci are C-shaped or semicircular fibrocartilaginous structures with bony attachment at anterior and posterior tibial plateau. The medial meniscus is C-shaped, with a posterior horn larger than the anterior horn in the anteroposterior dimension. The capsular attachment of medial meniscus on the tibial side is referred to as the coronary ligament. A thickening of the capsular attachment in the midportion spans from the tibia to femur and is referred to as the deep medial collateral ligament.

76The lateral meniscus is also anchored anteriorly and posteriorly through bony attachments and has an almost semicircular configuration. It covers a larger portion of the tibial articular surface than does medial meniscus

The fibrocartilaginous structure of the meniscus has a varied architecture of coarse collagen bundles.

At birth the entire meniscus is vascular.

By age 9 months, the inner one-third has become avascular. This decrease in vascularity continues by age 10 years, when the meniscus closely resembles the adult meniscus. 78In adults, only 10 to 25% of the lateral meniscus and 10 to 30% of the medial meniscus is vascular. This vascularity arises from superior and inferior branches of the medial and lateral genicular arteries, which form a perimeniscal capillary plexus.

Because of the avascular nature of the inner two-thirds of the meniscus, cell nutrition is believed to occur mainly through diffusion or mechanical pumping.

The classification of meniscal tears provides a description of pathoanatomy. The types of meniscus tears are:

Longitudinal tears that may take the shape of a bucket handle if displaced Radial tearsParrot-beak or oblique flap tears Horizontal tears and Complex tears that combine variants of the above.80HistoryMost meniscal injuries can be diagnosed by obtaining a detailed history.

Mechanism of injury

Meniscus tears are sometimes related to trauma;but significant trauma is not necessary.

A sudden twist or repeated squatting can tear the meniscus.

Meniscus tears typically occur as a result of twisting or change of position of the weight-bearing knee in varying degrees of flexion or extension.

82Pain from meniscus injuries is commonly intermittent; usually the result of synovitis or abnormal motion of the unstable meniscus fragment & is localized to the joint line.Mechanical complaints: Descriptions by patients are often nonspecific but include reports of clicking, catching, locking, pinching or a sensation of giving way.

Swelling usually occurs as a delayed symptom or may not occur at all. Immediate swelling indicates a tear in the peripheral vascular aspect.

Degenerative tears often manifest with recurrent effusions due to synovitis.83Physical findings Joint line tenderness Joint line tenderness is an accurate clinical sign. This finding indicates injury in 77-86% of patients with meniscus tears. Despite the high predictive value, operative findings occasionally differ from the preoperative assessment.

The examiner must differentiate collateral ligament tenderness that may extend further toward the ligament attachment sites above and below the joint line.84Effusion Effusion occurs in approximately 50% of the patients presenting with a meniscus tear. The presence of an effusion is suggestive of a peripheral tear in the vascular or red zone (especially when acute),an associated intra-articular injury, or synovitis.

Range of motion A mechanical block to motion or frank locking can occur with displaced tears. Restricted motion caused by pain or swelling is also common.

Provocative maneuvers

These techniques cause impingement by creating compression or shearing forces on the torn meniscus between the femoral and tibial surfaces.

86The McMurray test:This maneuver usually elicits pain or a reproducible click in the presence of a meniscal tear.The medial meniscus is evaluated by extending the fully flexed knee with the foot/tibia internally rotated while a varus stress is applied.The lateral meniscus is evaluated by extending the knee from the fully flexed position, with the foot/tibia externally rotated while a valgus stress is applied to the knee.One of the examiner's hands should be palpating the joint line during the maneuver.

The Steinmann test:Tibial rotation is performed with the patient seated and the knee flexed 90*.Asymmetric pain is created with external (medial meniscus) or internal (lateral meniscus) rotation.The Apley test:This maneuver is performed with the patient prone and the knee flexed 90*. An axial load is applied through the heel as the lower leg is internally and externally rotated. This grinding maneuver is suggestive of meniscal pathology if pain is elicited at the medial or lateral joint.

Differential diagonosis

Anterior Cruciate Ligament InjurySynovial Plica IrritationPatellofemoral Joint SyndromesIliotibial Band SyndromeKnee Osteochondritis DissecansPosterior Cruciate Ligament InjuryLateral Collateral Knee Ligament InjuryMedial Collateral Knee Ligament InjuryArticular cartilage pathology including arthritisBipartite patellaChondromalaciae patellaeRecurrent dislocation of patella.Patella alta/Patella baja/pseudo patella bajaSome avulsion fracture like Segond fracture and reverse segond fractureBiceps femoris avulsion fracturePatellar tendon avulsion fractureTibial plateau fractureKnee dislocation.

89Imaging StudiesPlain radiography: An AP weight-bearing view, PA 45* flexed view, lateral view and Merchant patellar view should be obtained to rule out degenerative joint changes (arthritis) or fractures

Arthrography: Historically, arthrography was the standard imaging study for meniscal tears but it has been replaced now by MRI.

MRI: This is the standard imaging study for imaging meniscus pathology and all intra-articular disorders.

90Treatment91Acute PhaseRehabilitation ProgramPhysical Therapy92A home physical therapy program or simple rest with activity modification, Ice and NSAIDs is the nonoperative management of possible meniscus tears.

The physical therapy program goals are to minimize the effusion, normalize gait, normalize pain-free range of motion, prevent muscular atrophy, maintain proprioception and maintain cardiovascular fitness. Choosing this course of treatment must include consideration of the patient's age, activity level, duration of symptoms, type of meniscus tear, and associated injuries such as ligamentous pathology

A trial of conservative treatment should be attempted in all but the most severe cases, such as a locked knee secondary to a displaced bucket-handle tear93 Medical Issues/Complications

The main complication at this stage of treatment is the absence of healing and failure of symptoms to resolve.The natural history of a short (