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• The lecture discusses common diagnoses related to the knee joint complex.

Soft Tissue Components – Ligamentous Structures

• Anterior and posterior cruciate ligaments are cruciate shaped due to their "cross-shaped" relationship within the intercondylar notch of the femur.
• Cruciate ligaments are intracapsular and covered by a synovial lining.
• Blood supply to the cruciate ligaments is delivered via small vessels within the synovial membrane.
• Cruciate ligaments obtain their names based on the attachment point on the tibia.
• The anterior cruciate ligament (ACL) runs from he anterior tibia to the medial side of the lateral femoral condyle.
• The ACL runs superior, lateral, and posterior and comprises of two indistinct spiraling bundles.
• These fiber bundles are named according to their tibial attachments: anteromedial bundle (AMB) and posterolateral bundle (PLB).

ACL Injury

• The ACL damage may be determined via subjective and physical exams.
• A subjective comprises of the patients history and primary contributing factors.
• A physical exam should evaluate loss of end range knee extension.
• Positive diagnostic testing should also be completed such as Lachmann and Anterior Drawer tests.
• Noncontact ACL injuries are more likely during deceleration/acceleration movements when there is excessive quad contraction and reduced hamstring co-activation at or near full extension.

Posterior Cruciate Ligament

• During prone knee flexion, the hamstrings will slide the tibia posteriorly.
• Posterior slide is limited by passive tension in the PCL.
• Hamstrings are considered "PCL antagonists".

PCL Injury

• PCL injury is normally determined via a subjective and physical examination.
• A subjective exam may include patients history as well as knee pain with kneeling or deceleration.
• A physical exam may consist of a Loss of knee extension during gait or ROM with positive diagnostic tests: Posterior drawer, Posterior sag, and "Dial” Test.
• PCL injury is often associated with injury to the posterolateral corner.

Medial and Lateral Collateral Ligaments

• Medial and lateral collateral ligaments limit excessive knee motion within the frontal plane.
• MCL protects against a vargus force.
• LCL protects against a varus force.

Collateral Ligament Injury

• Collateral ligament injury can be determined via a subjective and physical exam
• A subjective exam comprises of the patients history.
• A physical exam may include: localized effusion, palpable tenderness, and testing at 30° flexion for pain and laxity

Menisci

• The medial meniscus is “C” shaped while the lateral meniscus is 4/5 of a complete circle
• Menisci are anchored at the anterior and posterior horns
• Exterior ends of the menisci are attached to the tibia and capsule by coronary ligaments.
• Menisci are relatively loose to allow motion (lateral > medial).
• The transverse ligament is anterior.

General Discussion of Meniscal Injuries

• Meniscal injuries are identified with a subjective and physical exam
• Subjective includes history, delayed effusion, and "catching"/"locking"
• Physical may indicate symptoms at extremes of motion and positive diagnostic tests: Joint line tenderness, McMurray, Apley, Thessaly while some patients may display pain at maximal end range flexion or pain with forced hyperextension
• There is a high incidence of meniscal tears with ACL injuries.

Terrible Triad

• Damage to the medial meniscus, medial ligament, and anterior cruciate ligament.

Patellofemoral Joint

• The patella loses much of its mechanical engagement with the intercondylar groove.
• When the knee extends through the last 20-30° of flexion, the primary contact point is the inferior pole.
• In full extension, the patella rests completely proximal to the groove against the suprapatellar fat pad.
• Important to assess mobility when evaluating.

Patellofemoral Joint-Kinematics

• When the tibia is in motion with the femur, the patella slides relative to the fixed intercondylar groove of the femur.
• The patella follows the direction of the tibia during knee flexion as a result of bony attachment of the patellar tendon to the tibial tuberosity.
• When the femur is moving with the fixed tibia, the intercondylar groove of the femur slides relative to the fixed patella.

Patellofemoral Joint Kinetics

• The patellofemoral joint experiences high magnitudes of compression force:
• Walking on level surfaces: 1.3x body weight
• Climbing stairs: 3.3x body weight
• Deep knee bends: 7.8x body weight
• Factors Affecting Patellar Tracking
• During Knee extension the quadriceps pulls the patella superiorly in the intercondylar groove.
• There is also a pull laterally and posteriorly.

Factors Affecting Patellar Tracking - Global Factors

• Global factors affect knee tracking include the alignment of the lower extremity and structures that resist excessive valgus or extremes of axial rotation of the tibiofemoral joint.
• Dysfunction is often associated with dysfunction in other joints such as the hip and ankle.
• Genu valgum can cause an increased Q angle with increased bowstring force at the patella.

Patellofemoral Dysfunction

• Historically, broad and inclusive and not precise terms were used to diagnose the dysfunctions.
• Past symptoms include Chrondromalacia Patellae and Patellofemoral Pain Syndrome (PFPS).
• Current classification systems include:
• Patellar Compression Syndromes
• Patellofemoral Instability
• PF Pain with Malalignment or Biomechanical Dysfunction
• PF Pain without Malalignment.

Knee Osteoarthritis - Subjective and Physical Exam

• A subjective examination might include gradual onset of pain and stiffness in the am.
• Risk factors include excess weight and prior history. and a capsular pattern.
• A physical examination might include posture/observation, genu varum, and instability/"Buckling".
• The symptoms also present as pain as an inhibition in quadriceps and general muscle weakness,.

Patellar Tendinopathy - Symptoms and intervention

• Pain is found localized to inferior pole of patella.
• Symptoms increase with load on knee extensors.
• Particularly during plyometric type activities involving the knee like jumping.
• Additional symptoms include reduced strength in gluteus maximus, quadriceps, and calf.
• Intervention should include:
• Assessing pain irritability
• Inflammatory Control, and eccentric exercises
• Strengthening and lengthening of involved muscle groups.
• Multi-angle isometrics OKC and CKC

Nerve Injuries at the Knee - Common Fibular/peroneal Nerve

• Composed of spinal nerves L4-S2

Nerve Injuries at the Knee - Saphenous Nerve

• Runs along the femoral nerve and has spinal nerves of L3 and L4.

Pediatric Knee Conditions

• Pediatric knee conditions may include Shinding-Larsen-Johansson syndrome and Osgood Schlatter's disease.
• Other pediatric conditions with knee pain may include Slipped Capital Femoral Epiphysis (SCFE) and Legg-Calve-Perthes Disease.

Knee "Red Flag" Indicating Serious Conditions

• Cellulitis
• Compartment Syndrome
• DVT
• Fractures
• Peripheral arterial occlusive disease
• Septic arthritis