Chapter 14Knee Injuries

The Knee

• Largest joint in the body

• Modified hinge joint• One of most

vulnerable joints to severe injury of any in the body

Knee Anatomy• Bones

– Tibia• Distal to the femur

• Major weight bearing bone

– Fibula • Not included as a true

knee bone

• Very little weight bearing

– Femur • Longest bone in the body

• Major weight bearing

– Patella • “floating bone”

Knee Anatomy• Ligaments

– Anterior cruciate ligament (ACL)

• “cruciate” means cross• Function of ACL and

PCL is to stabilize the knee from front-to-back

– Posterior cruciate ligament (PCL)

– Medial collateral ligament (MCL)

– Lateral collateral ligament (LCL)

ligaments

– Posterior cruciate ligament (PCL)

– Medial collateral ligament (MCL)

– Lateral collateral ligament (LCL)

Knee Anatomy• Cartilage (meniscus)

– menisci are horseshoe-shaped shock absorbers that help to both center the knee joint during activity and to minimize the amount of stress on the articular cartilage.

Meniscus

– Medial • More often injured than

lateral

• Often involved medial ligament

• C-shaped

– Lateral• O-shaped

Knee anatomy

• Patellar tendon– Runs from the

quadricep muscles, across the patella, and inserts into the tibial tuberosity

Knee Anatomy• Muscles and tendons

– Quadriceps-responsible for knee extension

• Vastus lateralis• Vastus medialis• Vastus intermedius• Rectus femoris

Quadriceps

Posterior Leg

– Hamstrings-responsible for knee flexion

• Biceps femoris• Semimenbranosis• semitendinosis

Hamstrings

Injury prevention • Structural alignment

can predispose an athlete to injury

Injury Prevention

• Proper strengthening and flexibility of quadriceps, hamstrings, and gastrocnemius muscles

Injury Prevention

• Preventative bracing for collateral ligaments

Genu valgum (knock-kneed)

Genu Varum (bow-legged)

Bracing

Knee injuries and Conditions

• Ligament Injuries– Sprains (ACL, PCL, MCL, LCL)

• 1st, 2nd, and 3rd degree

• Muscle and tendon injuries– Patellar tendinitis

• Bone injuries– Chondromalacia– Patellar dislocations

• Other common injuries– Meniscal injuries– Osgood-Schlatter disorder

Ligament Injuries

ACL injuries

• Function is to prevent tibia from moving forward on femur

• S/S of injury include the athlete feeling disabled, complain of the knee giving way, collapsing, and popping

ACL Injuries

• Usually the most serious of all knee injuries

• Can hear a pop or snap on injury

• Often injured when athlete is changing direction

ACL (cont.)• Can also be injured due

to hyperextension• rapid swelling and loss

of function• treatment- RICE, knee

immobilizer, crutches, follow-up with orthopedist

• Almost always require surgical reconstruction if torn

Surgical procedures• Tendon graft

– Patellar or hamstring

• Allograft– Cadaver tendon

Rehabilitation• 3 Phases of rehab include:

– controlling the pain and swelling in the knee – regaining knee motion– beginning to regain muscle strength

• Usually minimum 6 months• Conservative treatment for less active people

can be non-surgical and focus on all rehab– three components of non-surgical treatment are

physical therapy, activity modification, and the use of a brace

PCL injuries

• PCL prevents posterior tibial movement on the femur

• MOI: bent knee bears full weight, forced hyperflexion, or a blow to the front of the tibia

PCL

• Often minimal swelling

• Treatment- RICE, refer to physician

• Not often surgically repaired

• Rehab focuses on strengthening quad muscles

MCL injuries

• Usually results from a direct blow to the outside of the knee

• Mild sprains result in joint-line point tenderness, minimal swelling, and no joint laxity

MCL

• Moderate produces more swelling, discomfort, some loss of function, and some laxity

• Severe – produces large amount of laxity

MCL (cont.)

• Treat with RICE if mild• Moderate, may need immobilizer, rehab• Moderate to severe could involve the meniscus

and/or ACL and may require surgery

LCL injuries

• Less common than MCL injuries

• Usually occurs due to direct blow to medial side of knee

LCL

• Similar s/s except discomfort is on lateral aspect of knee

• Focus rehab on lateral thigh muscles and hamstrings

Muscle and tendon injuries• Patellar tendinitis

– Characterized by quad weakness and tenderness over patella

– Minimal swelling– Called jumper’s

knee

Patellar Tendinitis

– Pain after activity– Treat with ice,

NSAIDs, and restricting activity

– Rehab- address flexibility and weakness issues

Bone injuries

• Patellar-femoral syndrome– Pain and discomfort

around the patella often caused by patellar tracking problems

– Causes chondromalacia-the wearing away of the cartilage on the back of the patella

Patellar-femoral syndrome

• s/s aching and pain after prolonged sitting, pain when going up or down stairs, athlete feels grinding sensation with flexion/extension

Patellar-femoral syndrome

• Treatment involves correcting patellar tracking, strengthening vastus lateralis and medialis, improving flexibility of quads and hamstrings

Bone injuries• Patellar dislocation

– Most commonly dislocates laterally

– Occurs with bent knee and inward twisting

– Noticeable deformity, extreme pain

– Call EMS– Physician reduces

Patellar dislocation

– Treatment involves immobilization, then rehab to regain mobility and strengthen

– Can wear a knee sleeve post-injury to help prevent from happening again

Fractures

• Tib-fib fracture– Uncommon, but

immediate referral necessary

– Many structures involved

Dislocated knee

• Extremely rare

• Immediate transport

Meniscal injuries

Typically occur with a twisting motion or with hyperextension or hyperflexion

• s/s-pain over joint line, problems weightbearing, complain of clicking, catching, locking, inability to fully extend or flex, and swelling

Meniscal injuries

• Treatment- surgical removal of meniscus (meniscectomy)– More often treated with removal of torn areas only through

arthroscopy– Sometimes repair meniscus with sutures or staples– Numerous new methods of repair (i.e. transplants)– Aquatic therapy very useful (non-weight bearing)

Osgood-Schlatter disorder

• Inflammation and irritation of the insertion of the patellar tendon (tibial tuberosity) in youth

• Repeated stress and activity can cause patella to partially pull away from bone and cause a bump

Osgood-schlatter’s

• S/S- pain and discomfort, minimal swelling

• Restricted activity recommended

• Use pain as a guide for activity level

• Ice pre and post activity, NSAIDs

Osgood-schlatter’s

• Can try patellar tendon band or pad

• Usually improves by age 16 or 17

Osgood-Schlatter disorder

Special tests

Lachman’s test

Pivot shift test

McMurray’s test