18 Soft-Tissue Hip Injuries

Joshua D. Harris

18 Soft-Tissue Hip Injuries

Introduction

I. Soft-tissue injuries are very common athletic and nonathletic injuries.
II. Layered concept of hip pain generators:
1. Layer I: osteochondral.
2. Layer II: inert soft tissue—static stability.
3. Layer III: contractile soft tissue—dynamic stability.
4. Layer IV: neuromechanical—kinetic and kinematic chain.
III. Soft-tissue structural hierarchy: layer III:
1. Skeletal muscle:
  1. Muscle bundle:
    1. Surrounded by epimysium.
    2. Contains multiple fascicles.
  2. Muscle fascicle:
    1. Surrounded by perimysium.
    2. Contains multiple fibers (cells).
  3. Muscle fiber:
    1. Surrounded by endomysium.
    2. Contains multiple myofibrils.
  4. Myofibrils:
    1. Surrounded by sarcolemma.
    2. Contains multiple myofilaments.
    3. Sectioned into sarcomeres:
      - i. Z-line forms each end of a sarcomere.
      - ii. H-zone contains only myosin; bisected by M-line.
      - iii. I-band contains only actin; bisected by Z-line.
      - iv. A-band is the length of the myosin myofilaments.
  5. Myofilaments:
    1. Thick: myosin.
    2. Thin: actin.
  6. Muscle types:
    1. Type I: slow twitch; red fibers; oxidative:
      - i. Aerobic metabolism; fatigue resistant.
      - ii. More mitochondria and myoglobin than type II fibers.
      - iii. Endurance, posture, balance.
      - iv. Low power, low strength.
    2. Type IIa: fast twitch; red fibers; oxidative and glycolytic:
      - i. Anaerobic metabolism (up to 30 minutes).
      - ii. Medium power, medium strength.
    3. Type IIb: fast twitch; white fibers; glycolytic:
      - i. Anaerobic metabolism (up to 1 minute); fatigue prone.
      - ii. Sprinting, heavy weightlifting.
      - iii. High power, high strength.
  7. Muscle contraction types:
    1. Isometric: muscle length remains the same during contraction:
      - i. Static strength.
      - ii. Plank or bridge exercise.
    2. Isotonic: muscle tension remains the same during contraction:
      - i. Dynamic strength.
      - ii. Hamstring curl exercise.
      - iii. Concentric: muscle shortens during contraction.
      - iv. Eccentric: muscle lengthens during contraction:
        
        Greatest strengthening potential.
        
        Greatest injury risk.
    3. Isokinetic: muscles contract and joints move at constant velocity:
      - i. Dynamic strength.
      - ii. Requires special equipment.
2. Tendon:
  1. Tendon:
    1. Two types:
      - i. Paratenon covered:
        
        Better vascular supply than sheathed tendon.
        
        Majority of tendons around hip and pelvis.
      - ii. Sheathed.
    2. Surrounded by epitenon.
    3. Contains multiple fascicles.
  2. Tendon fascicle:
    1. Surrounded by endotenon.
    2. Contains multiple fibers.
  3. Tendon fiber:
    1. Surrounded by endotenon.
    2. Contains multiple fibrils:
      - i. Contains multiple microfibrils.
  4. Osseous attachment:
    1. Tendon.
    2. Fibrocartilage.
    3. Mineralized fibrocartilage.
    4. Bone.
3. Injury location:
  1. Most frequently at musculotendinous junction.
  2. Second most frequently at tendon–bone junction.

Anatomic Considerations

I. Muscle groups:
1. Biarticular (cross two joints):
  1. Cross hip and knee.
  2. Hamstring.
  3. Quadriceps.
2. Uniarticular (cross one joint):
  1. Adductors.
  2. Abductors.
II. Anterior ( Figs. 18.1 and 18.2 ):
1. Iliopsoas.
2. Rectus femoris.
3. Sartorius.
4. Rectus abdominis.
5. External oblique, internal oblique, transversus abdominis.
III. Posterior ( Figs. 18.3 and 18.4 ):
1. Gluteus maximus.
2. Hamstring.
3. Piriformis.
4. Short external rotators.
IV. Medial ( Fig. 18.5 ):
1. Adductor longus.
2. Adductor brevis.
3. Adductor magnus.
4. Gracilis.
5. Pectineus.
V. Lateral ( Fig. 18.3 ):
1. Gluteus medius.
2. Gluteus minimus.
3. Tensor fascia lata.
  
  Fig. 18.1 Anterior view of the pelvis: the iliacus and the psoas major unite to form the iliopsoas tendon immediately anterior to the hip joint and insert onto the lesser trochanter. (Source: Schuenke M, Schulte E, Schumacher U. Thieme Atlas of Anatomy. General Anatomy and Musculoskeletal System. 2nd edition, ©2014, Thieme Publishers, New York. Illustrations by Voll M and Wesker K.)
VI. Pelvic floor:
1. Levator ani (pubococcygeus, puborectalis, iliococcygeus).
2. Transversus perineum.
3. Obturator internus.
VII. Muscle action ( Table 18.1 ).
VIII. Sagittal pelvic balance:
1. Anterior pelvic tilt:
  1. Tight iliopsoas.
  2. Tight rectus femoris/quadriceps.
  3. Tight hip adductors.
  4. Weak gluteus maximus.
    
    Fig. 18.2 Anterior view of the right hemipelvis and thigh, illustrating the quadriceps and sartorius. The rectus femoris crosses both the hip and knee joints, acting as a hip flexor and a knee extensor. (Source: Schuenke M, Schulte E, Schumacher U. Thieme Atlas of Anatomy. General Anatomy and Musculoskeletal System. 2nd edition, ©2014, Thieme Publishers, New York. Illustrations by Voll M and Wesker K.)
    
    Fig. 18.3 Posterior view of the right hemipelvis. The gluteus maximus is the primary hip extensor, uniting with the tensor fascia lata laterally to form the iliotibial tract. (Source: Schuenke M, Schulte E, Schumacher U. Thieme Atlas of Anatomy. General Anatomy and Musculoskeletal System. 2nd edition, ©2014, Thieme Publishers, New York. Illustrations by Voll M and Wesker K.)
  5. Weak hamstring.
  6. Weak rectus abdominis.
  7. Increased lumbar lordosis:
    1. Exacerbated by tight psoas major.
2. Posterior pelvic tilt.
  1. Tight hamstring.
  2. Weak iliopsoas.
  3. Rectus abdominis activation.
  4. Gluteus maximus activation.
  5. Decreased lumbar lordosis.
    
    Fig. 18.4 Posterior view of the right hemipelvis and thigh, illustrating the hamstring muscle group. (Source: Schuenke M, Schulte E, Schumacher U. Thieme Atlas of Anatomy. General Anatomy and Musculoskeletal System. 2nd edition, ©2014, Thieme Publishers, New York. Illustrations by Voll M and Wesker K.)