Hip Anatomy: Acetabulum, Bursae, Femoral Triangle

• The acetabulum includes portions of the ilium, ischium, and pubis
• The acetabulum contains the lunate surface (articular cartilage-lined surface), acetabular fossa (non-articular with fat pad), acetabular labrum (increases joint coaptation), and acetabular notch (contains transverse ligament)
• Bursae clinically relevant to the hip are: iliopectineal, trochanteric, and ischial/ischiogluteal (relevant with prolonged sitting and bedrest)

Iliopectineal Bursa

• Overlies anterior hip/pubis
• Lies deep to iliopsoas

Trochanteric Bursa

• Located over greater trochanter
• Many tendons attach here - glute med, glute min, piriformis, obturator internus/superior gemellus/inferior gemellus
• Glute max tendon passes over the bursae posterolaterally

Femoral Triangle

• Borders are the inguinal ligament (superior), adductor longus (medial), and sartorius (lateral)
• Contains the femoral artery, vein, nerve, and lymph glands

Ligaments

• Iliofemoral ligament (Y ligament of Bigelow) is the strongest ligament in the human body and prevents excessive extension and internal rotation
• Ischiofemoral ligament prevents excessive extension and internal rotation
• Pubofemoral ligament prevents excessive abduction, extension, and internal rotation
• Ligamentum teres (ligament of the head of the femur) does not contribute to stability, but assists with joint nutrition
• Transverse acetabular ligament forms foramen for acetabular artery

Acetabulofemoral Joint

• Three degrees of freedom: Flexion/Extension, Abduction/Adduction, and Rotation
• The head of the femur is convex while the acetabulum is concave
• The resting position is 30° flexion, 30° abduction, and slight external rotation
• The closed pack position is extension, abduction, and internal rotation
• The capsular pattern of restriction is Flex-AB-IR > Ext-AD-ER
• ROM and End Feel:
  • Flexion - 120°, soft or firm
  • Extension - 15°, firm
  • ER - 50°, firm
  • IR - 35°, firm
  • AB - 45°, firm
  • AD - 30°, soft or firm

MMT Review

• Clinically valuable muscle groups to know: hamstrings, quads, rec fem, psoas major, sartorius, TFL, adductor group, glute med, glute min, glute max, and internal/external rotators

Angle of Inclination

• Measured in the frontal plane between the femoral neck and shaft
• Normal angle: 125° in adults, 150° in children
• Decreased angle (<120°) results in coxa vara and leads to genu valgum
• Increased angle (>125°) results in coxa valga and leads to genu varum
• Coxa vara is more common than coxa valga, both can be asymptomatic

Anteversion

• Measured in transverse plane between the femoral head/neck axis and the transcondylar axis of the femur, describing the hip joint position
• Normal: 8-15° (normal degree of anteversion at hip similar to cubitus valgus)
• Increased (15-30°) creates excessive anteversion and a forward/medial femoral orientation due to hip joint positional change
• Decreased (5-8°) creates retroversion, resulting in a backward/lateral femoral orientation due to a positional change at the hip joint
• Assessed with Craig’s test (Ryder's sign)
• Excess anteversion is a positional change of the hip joint

Consequences of Excessive Anteversion (>15°)

• Apparent excess medial rotation with decreased external rotation
• Unnatural (compensatory) toe-out stance or gait
• Natural (noncompensatory) toe-in stance or gait
• The higher the degree of anteversion, the more prone the hip is to degeneration or injury

Retroverted Hip

• Results in apparent excess lateral rotation and decreased medial rotation
• Unnatural (compensatory) toe-in stance or gait
• Natural (noncompensatory) toe-out stance or gait

Angle of Declination (Torsion)

• Measured in the transverse plane between the femoral head/neck and shaft, describing the femur's structure but not the hip joint
• Normal: 15°
• Increased angle of declination = 30° and results in antetorsion of the femoral shaft and a medial twist
• Decreased angle of declination = 5° and results in retrotorsion of the femoral shaft and a lateral twist

Intrinsic Stability

• Factors include the acetabulum and labrum enclosing more than half of the femoral head
• Coaptation force creates 25kg of pressure, holding the femoral head in the acetabulum
• Strong ligaments have a medial twist for a screw-home mechanism in extension for approximating surfaces

Dislocation

• The hip is stable and hard to dislocate in the closed pack position (Extension, Abduction, Internal rotation)
• The position of potential vulnerability for a hip dislocation is Flexion, Abduction, & Internal rotation
  • Flexion creates ligamentous laxity
  • Abduction and internal rotation create poor joint surface congruency
• Dashboard injury (MVA)

Weight Bearing Forces on the Hip

• On two legs: each femoral head receives force equivalent to half the upper body weight
• On one leg: each femoral head receives 3 times the weight of the body
  • The center of mass is midline (S2) whereas the femoral heads are lateral to the midline, creating a rotary force
  • Strong abductors are needed to counteract this force
  • With abductor weakness, the stance leg drops into adduction (non-stance leg dropping)

Abductor Muscles Responsible for Strength

• Glute med, glute min, and TFL
• Weak abductors cause two common gait patterns:

Pelvis Drops

• The pelvis drops to the opposite side of weakness => a short swing phase on the unaffected side (Trendelenburg gait)

Torso Lurches

• Leaning the upper body toward the side of weakness will shift the center of gravity lateral to the fulcrum to prevent dropping of the opposite side of the pelvis
• Both can occur due to weakness or antalgic responses to pain
• A cane on the unaffected side can prevent the torso from lurching

Arthritis

• In a normal stance, the acetabulum and femoral head are both oriented anteriorly, with the posterosuperior aspect weight-bearing and the anterior aspect not
• Alternating compression/decompression nourishes a joint with synovial fluid
• The anterior aspect of the femur is undernourished, leading to degeneration and arthritis over time
• Abnormal structural/biomechanical concepts (especially anteversion and antetorsion) would increase the incidence of arthritis

Assessment

• True hip joint pain is felt in the groin area (not the glutes or trochanter)
• The hip, pelvis, and lumbar spine function as one unit and should be assessed together
• Asymmetry at the AF joint specifically is suggested if all landmarks are symmetrical up to the greater trochanter, but then there is deviation
• Uneven level of trochanters indicates:
  • High side indicates coxa valga or long femoral neck
  • Low side indicates coxa vara, short femoral neck, or cartilaginous narrowing from hip joint degeneration

Nelaton's Line

• A line drawn from ASIS to same side ischial tuberosity
• A positive finding is that the trochanter is palpated well above this line
• Check unilaterally for extent of coxa vara or cartilaginous narrowing from hip degeneration

Strains

• Sudden, clear MOI event involving overstretching, overloading, or both with heavy eccentric force
• Most commonly occurs at the musculotendinous junction or in the muscle belly
• Aggravated by lengthening (stretch), contracting against resistance, or palpation
• The history, observation, and movement are helpful for framing the development/healing stage

Acute Stage

• Just happened
• Moderate-severe loss of function/ADLs
• SHARP (Swelling, Heat, Altered function, Redness, Pain)
• Moderate-severe limitation in range and pain with movement (edema and muscle guarding)

Early Subacute

• Swelling has gone down
• Slight function improvement
• Bruising with red/blue/purple color
• Generally painful throughout range of movement

Late Subacute

• Function has improved since the injury
• Bruising, yellow/green/brown
• Generally painful only at end-range of movement/POP

Chronic

• ADLs would be back to normal unless the injury was very severe
• No bruising
• Generally not painful, but possible to have pain with tissue stress (load or POP)

Common Strains of the Hip

• Hamstrings commonly occur proximally or mid-belly
• Biceps femoris is the most common hamstring strain
• The hamstring MOI is eccentric contraction (terminal swing phase of sprinting gait)
• What active, passive, and resisted movements would provoke somebody who has a strained hamstring?
• Hamstrings are undergoing a strong eccentric force

Hamstring Assessments

• 90-90 leg raise
• Hamstrings MMT
• Rule out adductor magnus strain

Rectus Femoris

• Most common quad because of two-joint action with sprinting, kicking, and jumping
• What active, passive, and resisted movements would provoke somebody who has a strained rec fem?

Rectus Femoris Assessments

• Modified thomas test
• Ely's test
• Quads MMT
• Rule out TFL and iliopsoas strains when the location is high, close to ASIS

Adductors

• Most commonly adductor longus
• Occurs either at the origin on the pubic tubercle or musculotendinous junction about 5cm distal to pubic tubercle
• MOI is cutting movements/rapid change of direction, or sudden loss of balance such as on ice
• What active, passive, and resisted movements would provoke somebody who has a strained adductor longus?

Adductor Strain Assessments

• Try to differentiate the specific adductor (long or short / flexor or extensor)
• Adductor MMT
• Rule out hamstring strain when hamstring is especially medial

Groin Strain

• Lay person's term for any medial/anterior thigh pain; nonspecific umbrella term
• Referred pain is not uncommon, may be of lumbar origin

ITB Sprain

• Localized pain around greater trochanter
• Usually the MOI is a fall or blunt impact
• Aggravated by lengthening tissue over the top of it
• The assessment is an accessory test

ITB Fasciitis

• Diffuse pain around lateral thigh associated with TFL overuse
• Causes diffuse radiating pain through the thigh and can be misdiagnosed as sciatica

ITB Friction Syndrome

• Typically studied in the knee section

Tendonitis/Tendinopathy

• Can occur in commonly affected tendons such as rec fem, psoas, and iliopsoas

Rec Fem Tendonitis

• Overuse of combined hip flexion/knee extension like running, jumping, and kicking
• Is proximal just below AIIS
• Same assessment and provocation as the strain

Psoas/Iliopsoas Tendonitis

• Overuse of hip flexion
• Pain is felt over the lesser trochanter in the anterior thigh/hip/groin area
• There may be some anterior snapping/clicking sensation with hip movement if the tendon thickens due to overuse
• What active, passive, and resisted movements would provoke a psoas tendinopathy?

Bursitis

• There are three clinically relevant bursae at the hip: trochanteric, iliopectineal, and ischiogluteal bursitis

Trochanteric Bursitis

• Bursa is irritated by overuse of glute med, min, & max, and is caused by external rotators or trauma to greater trochanter
• If inflamed, may experience snapping sensation around trochanter with pain going up stairs, getting in/out of the car or chair, or lying on the side

Trochanteric Bursitis Assessments

• Bursitis-tendonitis differentiation test (Pain with compression does not get worse with load, especially eccentric load)
• Secondary finding to accessory test or Ober's test
• POP adduction, RROM abduction, and AROM abduction are also possibly provocative

Iliopectineal Bursitis

• Pain is felt deep in the groin (just over the hip joint)
• Overuse of the iliopsoas when trying to flex against resistance (rugby scrum, MMA)
• Decreasing the tone/use of the iliopsoas can relieve symptoms and offload the iliopectineal bursa
• The location can cause iliopectineal bursitis to mimic hip joint pathology

Iliopectineal Bursitis Assessment

• Pain with POP extension
• Pain is possible with Iliopsoas MMT or RROM hip flexion

Ischiogluteal Bursitis

• Caused by trauma or prolonged compression
• Typical for bedridden people, sitting for excessive periods, or having low amounts of tissue superficial to the bursa
• If inflamed, hamstrings, walking, and stairs use will be provocative

Fractures

• High risk of avascular necrosis following hip fracture due to compromised circumflex arteries
• Following fracture, joint effusion within the capsule occludes the circumflex arteries leading to avascular necrosis

Femoral Head Fracture

• Often involves a hip joint dislocation and massive trauma

Femoral Neck Fracture

• Subcapital or intracapsular fracture
• High risk of avascular necrosis

Subtrochanteric Fracture

• Femoral shaft fracture

Osteoarthritis

• Degenerative arthritis common at the hip
• The primary cause is idiopathic due to aging
• Secondary to trauma or immobilization

Pathophysiology

• Articular cartilage erosion and subchondral bone
• Leads to Wolff’s law > creation of osteophytes
• Pain results in decreased articular cartilage and immobility

Osteoarthritis Signs & Symptoms

• Insidious onset
• AM stiffness from articular gelling due to viscous synovial fluid after immobility such as sleeping
• Painful with prolonged use, relieved by rest
• Deep groin pain where the hip joint is located
• Stiffness begins as internal rotation and extension
• Develops into a full capsular pattern of restriction over time

Osteoarthritis Assessment

• If undiagnosed, perform a hip scouring test
• If diagnosed, assess per chief complaint

Total Hip Arthroplasty (Replacement)

• The joint is vulnerable to dislocation, complications, or injury for 12 weeks post-surgery
• Must avoid Flexion past 90 and Adduction past neutral in these 12 weeks
• Best to avoid lying on the non-operated side

Hip Dislocations

• Usually occurs in the open pack position; Flexion creates ligamentous laxity, ABD and INT ROT create poor congruency of joint surfaces
• The MOI is classic typically a dashboard injury (MVA)
• Dislocations are almost always posterior

FAI (Femoroacetabular Impingement)

• Due to bony deformity combined with vigorous, repetitive movement
• Essential components:
  • Abnormal morphology of the femur and/or acetabulum
  • Abnormal contact between the two structures
  • Vigorous, supra-physiologic motion which causes abnormal contact
  • Repetitive motion resulting in the continuous insult
  • Presence of soft tissue damage

Abnormal Morphology

• Present at birth or develops in adolescence

1. Cam-type is caused by an abnormal bony growth on the femur
2. Pincer-type is caused by an abnormal bony growth of the acetabulum
3. Combined is caused by both femoral and acetabular abnormalities

Diagnosis is Based On

1. A symptomatic hip which has pain, especially during movement, and stiffness
2. Postive FADIR test (or similar)
3. Postive x-ray findings

Massage is Similar to Hip Osteoarthritis

• Maintain maximum muscular support around the hip joint and avoid hip end range positions, flexion, and internal rotation/adduction

Capsular Sprains

• Normally presents as restriction in Flexion & Internal Rotation
• May develop into full capsular pattern (Flexion > Abd > Int Rot)
• Difficult to assess (almost a diagnosis of exclusion)
• Caused by twisting motions and occurs in dancers and athletes

Capsular Sprain Treatment

• Treat as any other sprain
  • Do not stretch or challenge tissue early
  • Decrease edema
  • Give it time to heal
  • Treat compensatory soft tissue structures

Piriformis Syndrome

• Review your PNS Tx class for this condition

Home Care Principles

• Programs must not cause pain/inflammation
• Be progressive and gradual
• Start as early as possible (no-inflamation)

Exercise Selection

• If in doubt, strengthen glutes
• Loaded exercises performed in mid-range
• Exercises which try to increase range are performed unweighted
• Avoid end-range loading
• Isometric exercises before eccentric exercises, concentric exercises, and plyometric exercises
• Gravity removed like therabands are before gravity added such as squats
• Work bilaterally before unilaterally

Program Issues/Signs

• Discomfort post exercise lasting more than 2 hours in acute/subacute stage
• Discomfort post exercise lasting more than 4 hours in the chronic stage
• Needing pain medication to control discomfort after activity or exercise
• Pain at rest, extreme fatigue, and rebound muscle spasm (not DOMS)

Hip OA/Joint Pathology Ideas

• Supine with band for glute activation with feet on floor for 1 min and feet on wall for 1 min
• Seated with band above knees, each 5-15s holds for hip abduction, hip flexion, and hip adduction
• Sit to stand out of chair
• Standing short lunges for load acceptance in quads
• PROM or pain-free AROM
• Supine, with towel or similar

Sit in Rocking Chair

• Gentle oscillations toward the general LPHC

Warm-Up in Bed to Decrease Joint Stiffness

• Hip circles and pelvic rocking
• Know a stretch for common muscles
• Glutes
• Quads & hip flexors
• Hams
• Adductors
• External rotators

Glute Strengthening

• Clamshells are the best glute isolation exercise compared to the hams and erectors and fire hydrants
• Bridges are good general strengthening, activating a lot of the hamstrings and erectors

Home Exercises

• Two-legged squats
• Crab walking with band above knee