Knee & Hip Anatomy, Movements, Injuries, and Special Tests
Knee Articulations
Tibiofemoral Joint
Tibiofubular Joint
Patellofemoral Joint
Knee Movements
Flexion: 0 – 130 to 145 degrees
Extension: 0 – 10 degrees
Internal Rotation: 10 degrees
External Rotation: 30-40 degrees
Knee Ligaments and Stress Tests
MCL: Valgus stress test
LCL: Varus stress test
PCL: Posterior drawer test, Godfrey’s 90/90 test
ACL: Anterior drawer test, Lachman test, Prone Lachman test
Menisci
The menisci are C-shaped fibrocartilage structures that:
- Deepen the knee joint and improve load transmission
- Improve lubrication
- Provide shock absorption
- Increase passive joint stability
- Limit flexion and extension extremes
- Serve as proprioceptive organs
Meniscal Zones and Healing Potential
Red Zone: Outer rim, most vascularized, highest healing potential
White Zone: Inner portion, avascular, no healing potential
Pink Zone: Between red and white zones, slightly vascularized, some healing potential
Meniscal Injury Tests
McMurry Test
Thessaly Test
Apley Compression/Distraction Test
Muscles of the Knee
Hamstring Muscles
- Biceps Femoris
- Semitendinosus
- Semimembranosus
Quadriceps Muscles
- Rectus Femoris
- Vastus Lateralis
- Vastus Medialis
- Vastus Intermedius
Patella
The patella provides:
- Protection for the anterior knee
- Increased mechanical efficiency for the quadriceps
- Absorption of joint reaction forces
Ruptured Patellar Tendon
Mechanism of Injury (MOI): Hyperflexion of the knee or a powerful quadriceps contraction from a weight-bearing position
Signs and Symptoms (SS): Gross deformity, gross swelling, inability to extend the knee
Intervention: Immediate immobilization, transportation to the hospital, surgical intervention within 7-10 days, rehabilitation to restore full function
Return to Play (RTP): Approximately 12 months
Femur and Hip Anatomy
Angle of Torsion: Amount of twist in the femur
Femoral Triangle: Formed by the inguinal ligament, Sartorius, and Adductor Longus muscles. Contains the femoral nerve, femoral artery, and femoral vein.
Nerve Roots: Lumbar plexus (T12-L4), Sacral plexus (L4-S4)
Femoral Variations:
- Anteverted Femur: Increased angle of torsion
- Retroverted Femur: Toe-out gait, increased external rotation
Hip and Pelvis Conditions
Osgood-Schlatter Disease: Inflammation of the patellar ligament at the tibial tuberosity
Sinding-Larsen-Johansson Disease: Inflammation of the bone at the bottom of the patella
Synovial Plica: Normal folds of fibrous membrane in the joint cavity
Slipped Capital Femoral Epiphysis: Displacement of the femoral head relative to the femoral neck
Legg-Calve-Perthes Disease: Ischemic lesion of the femoral head in adolescents
Cam Lesion: Abnormally shaped femoral head causing compressive forces
Pincer Lesion: Abnormally shaped socket that excessively covers the femoral head
Athletic Pubalgia (“sports hernia”): Result of increased muscular loads on the pubis from repetitive twisting, cutting, running, and kicking activities
Pelvis
The pelvis consists of three bones:
- Ilium
- Ischium
- Pubis
Hip Muscles
Hip Flexors
- Psoas Major
- Psoas Minor
- Iliacus
Posterolateral Hip Muscles
- Piriformis
- Quadratus Femoris
- Obturator Internus
- Obturator Externus
- Gemellus Superior
- Gemellus Inferior
Hip Movements
Flexion: 0 to 120 degrees
Extension: 0 to 30 degrees
Internal Rotation: 0 to 45 degrees
External Rotation: 0 to 45 degrees
Adduction: 0 to 30 degrees
Abduction: 0 to 45 degrees
Hip Dislocations
Hip dislocations typically occur when the hip is flexed and adducted, and an axial force drives the femoral head posteriorly through the capsule.
Common Position of Dislocation: Adduction and internal rotation
Hamstring Strain
Signs and Symptoms
- Popping or snapping sensation
- Antalgic gait with shortened swing phase
- Pain with resisted knee flexion, passive hip flexion, and knee extension
- Pain during activity
Thomas Test
The Thomas test assesses for iliopsoas tightness. If the leg on the table lifts when the opposite knee is pulled to the chest, it indicates a tight iliopsoas.