The Knee

Basic Anatomy

Basic Anatomy• Ligaments

– Anterior Cruciate Ligament (ACL)• Prevents femur moving posteriorly during weight bearing• Attaches anterior tibia to lateral femur

– Posterior Cruciate Ligament (PCL)• Primary stabilizer & stronger than ACL• Attaches posterior femur to anterior tibia

– Medial Collateral Ligament (MCL)• Taut during knee flexion & relaxed in extension• Prevents knee from valgus and external rotating forces• Attaches medial femur & medial tibia

– Lateral Collateral Ligament (LCL)• Taut during knee extension & relaxed in flexion • Attaches to the lateral femur & head of fibula

• Meniscus– Medial meniscus: C-shaped fibrocartilage– Lateral meniscus: O-shaped fibrocartilage

• Each meniscus is divided into 3 circumferential zones: – Outer zone = good vascular supply– Middle zone = minimal vascular supply– Innner zone = avascular

Knee Injuries

Prevention of Knee Injuries 1. Physical conditioning

• Muscles surrounding knee joint must be strong and flexible

• Focus on hamstring, erector spinae, groin, quadriceps, gastrocnemius flexibility

2. Rehabilitation and skill development • Strength, balance and technique - sport specific

3. Shoe Type• More and shorter cleats

• MCL sprain

Cause: – valgus force (lateral blow) or severe outward

twist– Greater injury results from medial sprains vs.

lateral sprains

S&S: • Grade I = few ligamentous fibers are torn and stretched;

joint is stable, little/no swelling, possible joint stiffness & point tenderness, full ROM

• Grade II = complete tear of deep cpsular ligament and partial tear of of MCL; slight laxity in full extension, no gross instability; no/little swelling; moderate to severe joint stiffness with inability to fully extend the knee; decrease PROM; medial pain

• Grade III = complete loss of medial instability; swelling; immediate severe pain followed by dull ache; loss of motion because effusion and hamstring guarding

Care: RICE; crutches; immobilzer; ROM exercises; rehabilitation; hinge brace (grade I, II)

• LCL sprain

Cause: – varus force & internal rotation of the tibia– Less prevalent than MCL

S&S:

• Grade I = joint is stable, little/no swelling, possible joint stiffness & point tenderness, full ROM

• Grade II = slight laxity in full extension, no gross instability; no/little swelling; moderate to severe joint stiffness with inability to fully extend the knee; decrease PROM; lateral pain

• Grade III = complete loss of lateral instability; swelling; immediate severe pain followed by dull ache

Care: RICE; crutches; immobilzer; ROM exercises;rehab; hinge brace; surgery controversial

• ACL sprain

Cause: foot planted, femur externally rotated

S&S: hear/felt “pop”; immediate disability; rapid swelling; intense pain immediately then subsiding

Care: RICE; crutches; immobilizer; surgery likely; 3-5 wks in brace; rehab 4-6 months

• PCL sprain

– Called the most important ligament in the knee– Provides central axis for rotation– Provides ~95% restraint of posterior displacement of tibia

Cause: most at risk when knee is bent hyperflexed knee with full weight on anterior aspect of knee and foot plantarflexed; rotational force which may affect medial/lateral side of knee

S&S: pop in back of knee; tenderness and swelling in back of knee (popliteal fossa); laxity of ligament

Care: RICE; Grade 1 & 2 - non-op, rehab focusing on quad strengthening; rehabilitation; controversy over surgery

• Meniscus injuries

Cause: weight bearing combined with rotational stress while extending/flexing knee

S&S: may or may not result in effusion gradually over 48-72 hrs; joint line pain and loss of motion; intermittent locking/giving way; pain with squatting

Care: RICE; recovery depends on location of tear; not uncommon to return 6-14 days after surgery (menisectomy); repaired meniscus may require immobilization for 5-6 wks, longer recovery

• Bursitis

Cause: acute, chronic, recurrent; prepatellar and deep infrapatellar have highest incidence; prepatellar inflamed from continued kneeling or falling directly on knee; infrapatellar irritated from overuse of patellar tendon

S&S: localized swelling; redness; increased temperature; pain due to swelling

Care: eliminating cause; rest; swelling; compression; padding; NSAIDs; possible aspiration

• Iliotibial band friction syndrome (Runners knee)

– Overuse condition commonly in runners and cyclists who have genu varum and pronated feet

– Irritation develops at the band’s insertion over the lateral femoral condyle causing friciton

Cause: overuse that can be attributed to malalignment and structural asymmetries of the foot and lower leg;

S&S: tenderness along ITB; little/no swelling; pain increases with activity

Care: stretch ITB; massage; foam roller: correction of foot and leg alignment problems; ice

• Chrondromalacia

– softening and deterioration of the articular cartilage on back of patella

– Exact cause is unknown– Abnormal patellar tracking due to numerous

factors

Chondromalacia undergoes 3 stages:

• Stage 1 = swelling and softening of articular cartilage

• Stage 2 = fissuring of the softened articular cartilage

• Stage 3 = deformation of the surface of the articular cartilage caused by fragmentation

• Chondromalacia

S&S: pain anterior knee while walking, running up/down stairs or squatting; recurrent swelling around kneecap; grating sensation when flex/ext knee

Care: avoid irritating activities; isometric ex; NSAIDs; neoprene sleeve; possible sx

• Patellar tendonitis (jumper’s knee)

Cause: jumping, running, or kicking repetitively– Sudden or repetitive forceful extension of knee may begin an

inflammatory process that will eventually lead to tendon degeneration

S&S: tenderness; pain; – 3 stages:

• Stage 1 - pain after activity• Stage 2 - pain during and after but functional• Stage 3 - pain during and prolonged after activity; may progress

to constant

Care: avoid irritating activities; RICE; patellar tendon brace; NSAIDs; transverse friction massage (TFM)

• Osgood-Schlatter disease

Cause: adolescent; repeated pull of patellar tendon at the tibial tubercle; bony callus forms and tubercle enlarges; usually resolves in late teen years

S&S: repeated irritation causing swelling; hemorrhage, and gradual degeneration of tibial tubercle; severe pain when kneeling; jumping and running; point tenderness

Care: stressful activities; ice before and after activity; isometric strengthening of quads and hams

• Patellar dislocation

Cause: quad muscle pulls in a straight line and patella pulls laterally creating a force that may sublux/dislocate patella

S&S: complete loss of knee function; pain with swelling; obvious deformity; possible fracture

Care: ice; referral with a dislocation - spontaneous reduction may occur if

athlete is able to straighten knee

• Osteochondritits Dissecans

– A painful condition involving partial or complete separation of a piece of articular cartilage and subchondral bone

– Exact cause is unknown– Possible causes =

• direct or indirect trauma• skeletal or endocrine abnormalitites• prominent tibial spine or part of patella

impinging on medial femoral condyle

• S&S: achy knee, swells recurrently, may catch or lock, possible atrophy of quadriceps

• Care: for children, rest and immobilization; may take as long as 1yr to resolve; surgery = drilling in the area to stimulate healing, pinning loose fragments, or bone grafting(Amare Stoudamire, Greg Oden)