orthopedic and rheumatologic disorders of the knee jointPresentation Transcript
The Knee Joint Rima Qudah Ahmed Al-Momtan C-2
Loss of function
Signs: upright, supine, lying prone
Valgus or varus deformity
Unilateral vs bilateral
Obeservation while walking.
Position of knees.
Old scars, sinuses or small lumps
quadriceps muscle wasting
Soft tissue and bony outlines palpation
Tests and maneuvers:
tests for intra-articular fluid
Patellar hollow test
Patellar friction test
The apprehension test
Tests for ligamentous stability
Scars or lumps in the popliteal fossa.
AP- and lateral views are standard.
Patellofemoral (skyline) and intracondylar or (tunnel) views are needed.
MRI-if doubtful meniscal or ligament injuries.
Genu Varum and Genu Valgum)
By end of growth, knees are normally in 5-7 degrees of valgus.
In children are considered as a stage of development
Valgus and varus in adults.
Lesions of Menesci
1- Meniscal tears:
Common in young adults
Caused by forced grinding it between the femur and tibia
In the young, occurs when weight is being taken on the flexed knee and there was twisting strain simultaneously common in footballers.
In middle age,fibrosis has restricted mobility of meniscus, tears occur with relatively little force
Medial meniscus is more affected, because of its attachmet to the capsule less mobile.
Patterns of meniscal tears
a) Bucket-handle tears
b) Horizontal tears
Most of the meniscus is avascular spontaneous repair doesn’t occur unless the tear is in the outer third
Clinical features of meniscal tears
From Hx, the patient is young, who sustains a twisting injury to the knee on the sports field
“ giving way”
Joint is held slightly flexed, there’s often an effusion,
In late presentations, quadriceps will be wasted
Apley’s test +ve!
Plain x-rays (normal),
MRI is reliable
Can be Diagnositic and therapeutic!
t/t in the past is by open operation.
now; is by arthroscopic surgery
For peripheral tears, operative repair is feasible
In case of displaced portion clean excision.
Continue, Lesions of menisci
2- Meniscal cysts
Can be linkened to a ganglion: fibrous tissue containing gelatinous fluid!.
Its probably traumatic in origin!
Clinical features of meniscal cysts and Treatment
History and P/E
Lump (seen and felt)-usually on the lateral side of joint
Either decompression or removal arthroscopically, and if any meniscal lesion, can be dealt with at the same time
Is an escape of a small, well demarcated, avcascular fragment of bone and overlying cartilage and sometimes separates; from one of the femoral condyles and appears as a loose body in the joint.
Most likely cause is trauma
Either single impact with the edge of the patella
Or repeated contact with adjacent tibial ridge
More than 80% of lesions occur on the lateral side of the of the medial femoral condyle, 25% have the lesion bilaterally.
Clinical features of osteochindritis dissecans
Usually a male patient, aged 15-20 y/o
Intermittent ache or swelling
Giving way (later)
Lock from time to time
quadriceps is wasted
Little swelling-will small effusion
Plus Two important signs
tenderness localized to one femoral condyle.
Wilson’s sign: if the knee is flexed to 90 degrees, rotated medially and the gradually straightened, pain is felt, if the test is repeated with the knee is rotated laterally, the patient feels no pain.
Investigations in osteochondritis Dissecans
Plain X-rays esp (tunnel) veiws – show a line of demarcation around a lesion.
Radionuclide-increased activity around the lesion
MRI-hypointensity in T1 images
Treatment of Osteochndritis dissecans
In earliest stage, cartilage is intact and the lesion is stable no t/t is needed but activities must be curtailed for 6-12 months, small lesions often heal spontaneously.
If the fragment is unstable (i.e. surrounded by a clear boundary with sclerosis of the underlying fibrocartilage large fragment (> 1 cm in diameter) can be shaped to fill the crater and should be fixed in situ with pins or Herbett screws.
If one the above was done, after 6 weeks, encourage movement! But not weight-bearing activities.
Knee is relatively capacious with large synovial folds, so it’s a haven for loose bodies.
Loose bodies can be produced by:
Injury (a chip of bone or cartilage)
Osteochondritis dissecans (may produce one or two fragments
Osteoarthritis (piece of cartilage or osteophyte).
Charcot’s disease (large osteocartligenous bodies are separated by repeated trauma in ajoint that has lost sensation).
Synovial chondromatosis (carilage metaplasia in the synovium sometimes producing hundred of loose bodies.
May be asymptomatic!.
Sudden “locking” without Hx of injury.
Feeling of something ‘popping’ in and out of joint.
Sometimes, esp after the 1 st attack, the knee swells up, due to synovitis
Try to find underlying cause!
“ joint mouse” when palpated for..
Imaging and Treatment
Most of the loose bodies are radio-opaque.
Sometimes you may find the underlying joint pathology!
removal! (arthroscopic), unless the joint is severely osteoarthritic.
Is increasing world wide!
Tuberculosis of the knee may appear at any age, but more common in children.
Clinically and on X-rays
early: pain and limp
Swollen joint and low grade fever.
Thigh muscles are wasted
The knee is warm, and there is synovial thickening
Movement is restricted and often painful.
Mantoux test +ve, ESR is high!
In children, enlarged bony epiphyses
Joint space narrowing and progressive erosion are late signs.
DDx: monoarticular rheumatoid arthritis or juvnile chronic arthritis.
A synovial biopsy may be necessary to establish the diagnosis.
Knee is rested in a splint (during therapy)
If joint surfaces are destroyed, the knee is stiff, arthrodesis is recommended.
Chronic monoarticular synovitis
Sooner or later other joint become involved
Stage 1: (synovitis); the patient complain of pain and chronic swelling. There is some wasting, there maybe a large effusion and the thickened synovium is easily palpable.
Stage 2: (articular erosion); increasing instability of the joint, marked muscle wasting, some loss of flexion and extension.
Stage 3: (deformity): pain and disability are usually sever, in some patients the joint has only a jog of painful movement, in others. It becomes increasingly unstable and deformed.
General rheumatoid treatment plus: local splintage and injection of triamsonolone will usually reduce the synovitis.
More prolonged effect can be achieved by injection of tadiocolloids such as yttrium-90 ( 90 Y).
Synovectomy (rare), if other measures fail.
If deformity is marked, femoral or tibial osteotomy may improve funcion and relieve pain.
If there was bone distruction and joint is unstabel total joint replacement.
Knee is one of the most common sites for OA.
Usually There is a predisposing factor;
In many cases, no obvious cause can be found and here the condition is often bilateral and has strong association with Heberden’s nodes.
Cartilage breakdown usually starts in an area of excessive loading.
Characterstic features; cartilage fibrillation, sclerosis of the sub-chondral bone and peripheral osteophyte formation are usually present.
Patients are usually >50 y/o, tend to be overweight, may have long standing bow-leg deformity.
Pain: is the leading symptom
‘ Giving way’
ranges: obvious deformity (usually varus)
Scar if a previous operation
Quadriceps is usually wasted.
And DURING exacerbations only: warmth and synovial membrane thickining.
Movement is somewhat limited and is often accompanied by patellofemoral creapitus .
Weight bearing view is essential.
Tibiofemoral joint space is diminished (often only in one compartment)
Osteophytes and sub-chondral cysts are usually present and sometimes there is soft-tissue calcification in the suprapatellar region in the joint itself (chondrocalcinosis)
If symptoms are not very sever, t/t is conservative (analgesics, quadriceps exercises, and application of warmth, joint loading is lessened by using a walking stick).
Operative T/T is indicated if:
Persistent pain irresponsive to conservative t/t
Progressive deformity and instability
Girls are affected more commonly than boys, and the condition is often bilteral.
Stuck knee in flexion, may cause the patient to fall.
Patella is dislocated!
Tenderness on the medial side of the joint
The joint swells (later) and aspiration may reveal a blood-stained effusion.
Apprehension test +ve
If still dislocated, push it back into place while the knee is gently extended.
A plaster cylinder or splint id applied and retained for 2-3 wks
Isometric quadriceps-strengthening excercises are encouraged and the patient is allowed to walk on crutches.
Exercises should be continued for at least 3 months concentrating on strengthening the vestus medialis muscle.
If recurrences are few and far between, conservative treatment is enough as when the child gets older, patellar mechanisms tends to stabilize.
Principles of treatment are:
To repair or strengthen the medial patellofemoral ligaments. And
To re-align the extensor mechanism as to produce a mechanically more favourable angle of pull.
2- Patellofemoral overload ( patellar pain syndrome; chondromalacia of the patella )
Ant. Knee pain is common among active adolscents and young adults
Often associated with softening and fibrillation of the acrticular surface of the patella- chondromalacia patellae .
The basic disorder is probably repetitive mechanical overload of the patellofemoral joint due to either:
Malcongruence of the patellofemoral surfaces because of some abnormal shape of the patella or intercondylar groove. Or
Malalignment of the extensor mechanism, or relative weakness of the vesus medialis, which causes the patella to tilt, or subluxate or bear more heavily on one facet than other during flexion or extension
The patient often a teenage girl or an athletic young adult.
Pain over the front of the knee ‘underneath the knee-cap’
Aggravated by activity, climbing stairs or when standing up after prolonged sitting.
X-ray Should include skyline views of the patella.
May show abnormal tilting or subluxation.
Lateral view with the knee partly flexed to see if the patella is high or small.
Most accurate way of showing and measurement of malposition is by CT or MRI with the knees in full extension and farying degrees of flexion.
Arthroscopy and Differential Diagnosis
Arthroscopy is useful in excluding other causes of ant knee pain.
- Table page 234
Most cases respond to adjustment of stressful activities and physiotherapy.
Excercises are directed specifically at strengthening the medial quadriceps to counterbalace the tendency to lateral subluxation or tilting of the patella.
If Symptoms persist; surgery can be considered-lateral release or lateral release cobined with the realignment procedures (20.22 p 235)
If there is any sign of fibrillated cartilage is sometimes performed, but its efficacy is questionable.
Exposed areas of subchondral bone can be drilled.
Painful swelling of the tibial tubrcle.
Common in adolscents, particularly those engaged in strenous sports.
Often called “osteochondritis”
On P/E; the tibial tubrosisty is unusually prominent and tender.
Sometimes active active extension of the knee against resistance is also painful.
X-rays; show displacement or fragmentation of the tibial apophysis.
T/T: Spontaneous recovery is usual but takes time, its wise to restrict such activities as cycling and football.
Swellings around the knee
Fairly common complaint.
Could involve the entire joint, or asymmetrically on one or other aspect of the joint.
Can be acute or chronic.
A- Acute swelling of the entire joint.
Swelling immediately after injury means blood in the joint.
Painful, warm, tense and tender knee.
X-rays are essential to cheque for fractures, if there was no, suspect a tear of the ACL.
In patients with bleeding disordes, it is the most common site to bleed.
If the clotting factor is available, aspirate, splint and give the deficient clotting factor.
Acute septic arthritis:
swollen, painful, and inflammed joint.
WBCs, ESR are elevated.
Send aspirate for culture (including anaerobic).
Most common organism is Staph. Aureus.
In adult, gonococcus is as common!
t/t drainage, IV Antibiotics
Injury stimulates reactive synovitis.
The swelling appear only after some hours vs haemiarthrosis.
Subsides spontanuously over period of days.
Fluid aspiration hastens muscle recovery.
Aseptic non-traumatic synovitis:
With no Hx of trauma or signs of infection gout? Pseudogout.
Treatment with anti-inflammatory drugs is usually effective.
B- Chronic swelling of the entire joint.
Most common causes are OA, and RA.
Other signs: deformity, loss of movement, or instability.
X-ray will usually show characteristic features
Most important is to exclude TB
It is considered when no obvious alternative Dx.
Invetigations: mantoux testing, synovial biopsy and microbiological studies
The ideal is to start anti-TB before joint destruction occurs
Other joint aspect swellings
A- Swellings in front of the joint.
Prepatellar bursitis “house maid’s knee”.
Flactuant swelling confined to the front of patella.
The joint itself is normal.
It is an uninfected bursitis due to constant friction between skin and bone.
Seen in carpet layers, paving workers, floor cleaners who don’t use knee pads.
T/T; firm bandaging and avoidance of kneeling, occasionally aspiration is needed.
In chronic cases, the lump is best excised.
Infrapatellar bursitis “clergyman’s knee”:
The swelling is bellow the patella and superfacial to the patellar ligament.
More distal to prepatellar bursitis.
t/t is the same.
Other joint aspect swellings
B- Swellings at the back of the joint.
Semimembranous bursa :
Between the semimebranosus and the medial head of gastrocnemius.
May enlarge in children or adults.
Presents as a painless lump behind the knee, slightly to the medial side of the midline.
Best seen while the knee is straight.
Normal knee joint
t/t is ‘waiting policy’ even if causes some ache, it disappears with time.
Popliteal Cyst (Baker’s cyst”:
Bulging from the post capsule and the synovial herniation may produce a swelling in the popliteal fossa.
Most likely cause by RA or OA.
t/t is the same.
Popliteal Cyst “Baker’s cyst”:
Bulging from the post capsule and the synovial herniation may produce a swelling in the politeal fossa.
Most likely caused by RA or OA.
Sometimes it ruptures and its content descend down the calf muscle, causing pain, may be mistaken for a DVT.
It may diminish following aspiration, and injection of hydrocortisone.
Excision is not advised recurrence rate is high unless the underlying pathology is treated.
Other joint aspect swellings
C- Swellings at the side of the joint:
Small, tense, tender, swelling, usually at the lateral side at or just bellow the joint line.
Sometimes, can be soo tense, can be mistaken for a bony lump.
Calcification of the collateral ligament:
Acutely painful swelling, suddenly appear on the medial side of the joint.
Rubbery in consistancy and acutely tender.
Operative decompression confirms the Dx. And provide immediate relief.
The calcific material is extruded like toothpaste.)
Arises in long-bone metaphyses
Visible and palpable swelling in the vicinity of a joint.
If large, non-discrete and painful this could suggest a tumour.
Diagnosis can be made of by an X-ray, confirmed by tissue biopsy.
Acute knee ligament injuries
The bony structure of the knee is inherently unstable!, where it not for the strong capsule, intra-articular, extra-articular ligaments and controlling muscle, the knee wouldn’t be able to function effectively as a mechanism for support, balance and thrust.
Valgus stresses are resisted by:
Superfacial and deep layers of medial collateral ligament (MCL).
The tough posterimedial part of the capsule.
Varus stresses are resisted by:
Lateral collateral ligamnt (LCL).
Anteroposterior and rotatory stability by:
Anterior cruciate ligament (ACL).
Posterior cruciate ligament (PCL).
Injuries to these ligament are common particularly in sporting pursuits.
Maybe associated with fractures or dislocations.
Vary in degree, from simple sprain to complete rupture.
These injuries are seldom unidirectional >> involve more than one structure so; we refer to them by functional terms like “anteromedial instability” or anatomical “torn MCL and ACL”.
Hx of twisting or wrenching, and may claim to have heard a ‘pop’ as the tissue snapped.
The knee is painful.
Swelling appears immediately.
Tenderness is maximal on the torn ligament.
Stressing on one side of the joint, produces excoriating pain.
Sideways tilting (valgus, varus) is examined; first with the knee flexed to 30 degrees, then with the knee straight. Compare both sides.
Anteroposterior stability is assessed first by placing the knees at 90 degrees with the feet resting on the couch and looking from the side for post. Sag of the proximal tibia, if +ve, this is a reliable sign of PCL instability.
Lachman test; more reliable, anteroposterior glide is tested with the knee flexed 15-20 degrees.
Stress x-rays of the knee provide evidence of instability.
Plain X-rays may show that the ligament is avulsed a small piece of bone;
The MCL, usually from the femur.
The LCL from the fibula.
The ACL from the tibial spine.
The PCL from the back of the upper tibia.
Sprains and partial tears:
- The intact fibers splint the torn ones >> spontaneous healing. Active excecises are prescribed from the start.
Aspirating the haemiarthrosis and applying of ice-packs intermittently relieves the pain.
Weight bearing is allowed, but the knee is protected from angular or rotational movement by heavily padded bandage or a functional brace.
Isolated tears of MCL or the LCL can be treated as partial tears.
Isolated tears of the ACL may be treated by early operative reconstruction.
In all other cases, it is more prudent to follow the conservative regimen, the cast-brace is only worn until symptoms subside.
Isolated cases of PCL tears are usually treated conservatively.
Avulsion fractures of the tibial intercondylar eminence.
Caused by sever strain, instead of rupturing a cruciate lig, results in avulsion fracture of the insertion.
Maybe partially displaced difficult to detect on X-ray.
If the fragmment can be manipulated back into position, and allow full extension of the knee immobilization in plaster cylnder for 6 weeks.
Full movement is usually regained within 3 months.
ACL and collateral ligament injury, treat the joint bracing and physiotherapy in order to restore a good range of movement before following in with ACL reconstruction; the collateral doesn’t need reconstruction!
Similar approach is adopted for combined injuries involving the PCL, but here all damaged structures need to be repaired.
Adhesions; if the knee is not exercised, torn fibers stick to intact fibers and to the bone.
Instability gets worse and predisposes to OA reconstruction before the onset of degenerative changes.