Week 4 - Hip Conditions

What is PICO and give an example of its applicaiton

Helps formulate clinical questions; patient/problem, intervention, comparison, outcome

Range of motion (ROM)

The arc of motion that occurs at a joint or a series of joints, measured starting from the anatomical position.

Active range of motion (AROM)

The arc of motion attained by a subject during unassisted, voluntary joint motion, also referred to as physiological movement.

Physiological barrier

The end-point or boundary reached at the conclusion of active range of motion (AROM).

Passive range of motion (PROM)

The arc of motion attained by an examiner without assistance from the relaxed subject, also known as anatomical movement.

Anatomical barrier

The anatomical limit reached at the conclusion of passive range of motion (PROM).

Relationship between physiological and anatomical barriers

The physiological barrier occurs prior to the anatomical barrier; therefore, passive movement is almost always slightly greater than active movement.

Examiner observations during AROM

Onset, location, and quality of pain; movement compensation or trick movements; movement of associated joints; patient willingness to move; and overall movement rhythm and quality.

End feel

The sensation of a barrier restricting further motion felt by the clinician at the extreme end of passive range of motion.

Overpressure

The passive application of pressure by an examiner at the end of available range of motion to determine the quality of the end feel.

Hard (bone-to-bone) end feel

A normal, unyielding, painless sensation stopping motion, typically seen in healthy joint limits such as elbow extension.

Firm (tissue stretch) end feel

A normal end feel characterized by a firm, spongy sensation with slight elastic give, typically found in straight leg raises (SLR) or MCP joint extension.

Soft (soft-tissue approximation) end feel

A normal end feel characterized by a compressive, mushy stop as soft tissue bulks press together, commonly seen in knee flexion.

Empty end feel

An abnormal end feel where no mechanical barrier is reached because severe pain or muscle spasm halts the movement prematurely (e.g., post-dislocation).

Springy block end feel

An abnormal end feel characterized by a rebound effect occurring before full range of motion, caused by intra-articular disruption such as a meniscal obstruction.

Hypomobility

A decrease in passive range of motion substantially below normal values for a joint given age and sex, often presenting with an early or altered end feel.

Capsular pattern of restriction

A characteristic sequence of proportional motion loss across multiple directions of a joint, proposed by Dr. James Cyriax to indicate whole joint capsule involvement.

Hypermobility

An increase in passive range of motion that exceeds standard normal values for a joint, caused by laxity in ligaments, capsules, and muscles.

Hypermobility Syndrome (HMS)

Generalized joint hypermobility in an otherwise healthy individual presenting with musculoskeletal symptoms, arthralgia for over 3 months in 4 or more joints, and a Beighton scale score of at least 5.

0-180 notation system in goniometry

The standard method where anatomical position is defined as $0^\circ$, and joint movement progresses toward $180^\circ$.

Recommended chart documentation for goniometric evaluation

Patient demographics, examiner identity, date and time, goniometer type and size, side and joint measured, motion type (AROM or PROM), numerical ROM degrees, subjective pain reports, objective findings (protective spasm or end feels), and deviations from standard testing positions.

Threshold for clinically significant bilateral ROM difference

A difference of $\ge 7.5^\circ$, because average anatomical variation between dominant and nondominant extremities across joints is $7.5^\circ$.

Standard Error of Measurement (SEM) threshold in goniometry

Changes of $\ge 5^\circ$ indicate true clinical change, whereas changes of $< 5^\circ$ are attributed to measurement error (typical SEM ranges between $2.4^\circ$ and $4.9^\circ$).

Intratester vs. intertester reliability in goniometry

Intratester reliability (consistency by the same examiner across trials) is generally higher than intertester reliability (consistency between different examiners).

Methods to improve goniometric measurement reliability

Use standardized positioning, palpate well-defined bony landmarks at the end of motion, use the same measurement instrument, position eye level directly at the scale to avoid parallax error, and average multiple trials when less experienced.

Parallax effect in goniometric alignment

An observational reading error occurring when the examiner's line of sight is not directly perpendicular and level with the goniometer's protractor scale.

Muscle length

The maximal physical distance between the proximal and distal bony attachments of a muscle, reflecting the maximal extensibility of a muscle-tendon unit.

Clinical objective of muscle length testing

To determine whether joint hypomobility or hypermobility is caused by adaptive length changes in crossing musculature rather than capsular or ligamentous restrictions.

Measurement relationship during one-joint muscle length testing

No numerical discrepancy should exist between the muscle length test and the passive joint range of motion measured in the direction opposite to the muscle's contraction.

Positioning guideline for measuring joints crossed by multi-joint muscles

The multi-joint muscle must remain slack across all other joints it crosses to prevent muscle tightness from artificially restricting available joint PROM.

Passive insufficiency

The physiological inability of a multi-joint muscle to lengthen sufficiently to permit full, simultaneous range of motion across all joints it crosses.

Active insufficiency

The mechanical inability of a multi-joint muscle to shorten sufficiently to produce full range of motion or optimal contractile force across all crossed joints simultaneously.

Clinical differentiation between active and passive insufficiency

Passively move the target joint to the end of range while the agonist is fully shortened; if full PROM is attained without resistance from the antagonist, the limitation is confirmed active insufficiency.

Three-number ROM documentation (e.g., 20-0-135°)

A notation format where placing '0' between start and end values indicates the joint moves through neutral anatomical position, signifying hyperextension or hypermobility (e.g., $20^\circ$ of hyperextension to $135^\circ$ of flexion).

Gold standard for criterion-related validity in goniometry

Radiography, demonstrating strong correlation ($r = 0.97$) and agreement ($\text{ICC} = 0.98$) when compared to universal goniometer measurements.

Intratester vs. intertester reliability in goniometry

Intratester reliability (consistency by the same examiner across trials) is generally higher than intertester reliability (consistency between different examiners).

Positioning guideline for measuring joints crossed by multi-joint muscles

The multi-joint muscle must remain slack across all other joints it crosses to prevent muscle tightness from artificially restricting available joint PROM.

Grade 1 muscular strain

Tearing of only a few muscle fibers, presenting with mild pain and mild or no loss of strength.

Grade 2 muscular strain

Incomplete tearing of muscle fibers, presenting with significant pain, possible swelling or bruising, and moderate loss of strength.

Grade 3 muscular strain

Complete tearing or rupture of the entire muscle, presenting with significant pain (which may resolve quickly), severe swelling and bruising, and significant loss of strength.

Grade 1 ligamentous sprain

Tearing of only a few ligamentous fibers, presenting with mild pain and mild or no loss of joint stability.

Grade 2 ligamentous sprain

Incomplete tearing of ligament fibers, presenting with significant pain, possible swelling or bruising, and moderate loss of joint stability and function.

Grade 3 ligamentous sprain

Complete tearing or rupture of the entire ligament, presenting with significant pain (which may resolve quickly), severe swelling, bruising, and significant loss of joint stability and function.

Selective tissue tension testing (contractile vs. inert tissue)

Contractile tissues (muscles and tendons) increase in tension primarily when actively contracted or passively stretched, whereas inert tissues (ligaments, capsules, nerves, bursae, cartilage, discs) increase in tension primarily when passively stretched.

Inert tissue lesion pattern: pain-free and full ROM

Indicates that there is no lesion within the inert tissue being tested in that specific direction of passive movement.

Inert tissue lesion pattern: painful and limited or excessive movement in some directions

A noncapsular pattern of restriction pointing to a localized inert tissue injury, such as an isolated ligament sprain.

Inert tissue lesion pattern: painful and limited in all directions

A capsular pattern indicating that the entire joint capsule is affected, characteristic of arthritis or capsulitis.

Inert tissue lesion pattern: pain-free and limited movement

Presents with an abnormal hard (bone-to-bone) end feel, typically indicating symptomless osteoarthritis.

Manual muscle testing (MMT)

A diagnostic procedure used to evaluate the function and strength of individual muscles or muscle groups based on movement performance relative to gravity and manual resistance.

Art vs. science of manual muscle testing

The art involves careful handling, positioning to avoid pain, gentleness with weak muscles, and skilled resistance application; the science requires rigorous attention to every testing detail to ensure diagnostic accuracy.

Three conventional factors in MMT grading

Evidence of muscle contraction (visible or palpable), gravity as resistance, and the amount of manual resistance applied by the examiner.

Muscles tested without gravity resistance in MMT

Finger and toe muscles, forearm supination and pronation, facial muscles, and pelvic floor muscles (gravity is utilized as resistance in approximately $60\%$ of extremity tests).

MMT Grade 0 (Zero) and Grade 1 (Trace)

Grade 0 (Zero): No evidence of muscle contraction felt or seen ($0/5$).

Grade 1 (Trace): Palpable muscle tension or slight tendon prominence without observable limb movement ($1/5$).

MMT Grade 2-, Grade 2, and Grade 2+ (Poor grades)

Grade 2- (Poor Minus): Completes partial ROM in the horizontal (gravity-eliminated) plane.

Grade 2 (Poor): Completes full ROM in the horizontal plane ($2/5$).

Grade 2+ (Poor Plus): Completes partial ROM against gravity.

MMT Grade 3-, Grade 3, and Grade 3+ (Fair grades)

Grade 3- (Fair Minus): Exhibits gradual release from the test position against gravity.

Grade 3 (Fair): Holds the test position against gravity with no added manual pressure ($3/5$).

Grade 3+ (Fair Plus): Holds the antigravity test position against slight manual pressure.

MMT Grade 4-, Grade 4, Grade 4+, and Grade 5 (Good and Normal grades)

Grade 4- (Good Minus): Holds the antigravity position against slight to moderate pressure.

Grade 4 (Good): Holds against moderate pressure ($4/5$).

Grade 4+ (Good Plus): Holds against moderate to strong pressure.

Grade 5 (Normal): Holds against strong manual pressure ($5/5$).

Positioning guideline for measuring joints crossed by multi-joint muscles

The multi-joint muscle must remain slack across all other joints it crosses to prevent muscle tightness from artificially restricting available joint PROM.

Selective tissue tension testing (contractile vs. inert tissue)

Contractile tissues (muscles and tendons) increase in tension primarily when actively contracted or passively stretched, whereas inert tissues (ligaments, capsules, nerves, bursae, cartilage, discs) increase in tension primarily when passively stretched.

Visual and palpatory criteria for MMT grading categories

Palpable contraction or tendon prominence confirms Trace ($1/5$); observable limb motion in the horizontal plane confirms Poor grades ($2-/5$ or $2/5$); observable movement against gravity confirms Fair ($3/5$), Good ($4/5$), or Normal ($5/5$) grades.

Clinical limitations of isokinetic dynamometers

Difficulty providing sufficient stabilization to isolate muscle groups (allowing substitution), high purchase cost ($> \$60{,}000$), and excessive setup time required to secure the patient.

Sensitivity profile of manual muscle testing across grades

MMT scores are most sensitive to strength changes in lower grades ($0$ to $3$) and are insensitive to strength variations in higher grades ($4$ to $5$).

Examiner limitation in manual muscle testing

Grading accuracy in higher resistance grades ($4$ and $5$) can be restricted by the physical strength of the examiner relative to the patient.

Manual resistance and lever arm placement in MMT

Resistance should be applied using the longest lever arm possible and positioned as distal on the moving segment as possible without crossing additional joints.

Threshold for normal bilateral strength discrepancy in MMT

A strength difference of $< 10\%$ between the affected and unaffected sides is considered within normal limits (WNL).

Contraindications to manual muscle testing

Active inflammatory processes (e.g., acute rheumatoid arthritis flare), active localized infections, pain exacerbated by testing, situations risking further tissue disruption, recent abdominal or hernia surgery (due to Valsalva risks), and inability to comprehend or follow instructions.

Precautions during manual muscle testing

Cardiovascular conditions where breath-holding (Valsalva maneuver) is dangerous, pathology where overwork or fatigue is deleterious (e.g., multiple sclerosis), osteoporosis requiring modified pressure, and uncontrolled trick or substitution movements.

Resistance application protocol for antigravity MMT (Grades 3 to 5)

Place the joint in its mid-range position, instruct the patient 'Hold this position, don't let me move you,' and apply manual force opposite the muscle's line of pull gradually over $5\,\text{seconds}$.

Minimizing surface friction in gravity-eliminated MMT

Placing a slip-sheet beneath the moving extremity across the horizontal support surface to facilitate unhindered motion.

Differentiating joint ROM limitation from muscle weakness

Evaluate passive ROM immediately following incomplete AROM; if PROM is full and painless, the inability to move through full active range indicates muscle weakness rather than joint or soft tissue restriction.

Muscle substitution in MMT

An observational sign of target muscle weakness characterized by adjacent or synergist muscles attempting to compensate and perform the required movement.

Etiological causes of muscle weakness

Muscle strain, tendon pathology, avulsion injuries, pain or reflex inhibition, peripheral nerve lesions, nerve root lesions (myotomal distribution), upper motor neuron lesions (even in the presence of hypertonicity), and psychological overlay.

Positional weakness (mechanical disadvantage)

Reduced active muscle force generation when tested at extreme shortened (inner) or lengthened (outer) ranges, with optimal peak force occurring in the mid-range according to the length-tension relationship.

WOMAC

Western Ontario and McMaster Arthritis Index, outcome measure of Hip and Knee OA, self-administered, 24 items, 3 subscales: pain, stiffness, and physical function, 0-4 scale, higher score = greater disability

HOOS

Hip Disability and OA Outcome Score, outcome measure for hip problems and functional limitations, 40 items, 5 subscales: pain, symptoms, ADLs, sport & rec, QoL, 0-4 scale, inverted score, lower score = greater disability

iHOT

International Hip Outcome Tool, outcome measure for assessing a variety of hip conditions, 12 items, VAS, lower score = greater disability

Femoral anteversion

Normal = 8-15 degrees

Medial femoral torsion = >15 degrees = anteversion = toe in

Lateral femoral torsion = <8 degrees = retroeversion = toe out

Hip ROM

Flex: 110-120, Ext: 10-15, Abd: 30-50, Add: 20-30, IR: 30-40, ER: 40-60

Hip Osteoarthritis (OA)

A painful and stiff hip condition caused by gradual erosion of articular cartilage, common in the elderly. It results from a combination of mechanical, inflammatory, and metabolic factors causing an imbalance between tissue destruction and repair

Osteophyte formation mechanism

Bone-on-bone friction resulting from progressive articular cartilage degeneration stimulates the formation of abnormal bony outgrowths or spurs.

Hip dysplasia

Congenital or developmental structural abnormalities regarding the shape, size, orientation, or organization of the femoral head, acetabulum, or both, typically presenting as joint instability, a shallow socket, or subluxation.

Legg-Calvé-Perthes disease (LCPD)

A pediatric hip condition characterized by idiopathic osteonecrosis of the femoral head epiphysis.

Femoroacetabular impingement (FAI)

A clinical syndrome where morphological abnormalities of the femoral head-neck junction and/or acetabulum cause abnormal mechanical abutment during hip motion, predisposing to labral tears and early secondary osteoarthritis.

Primary vs. Secondary Hip Osteoarthritis

Primary hip osteoarthritis is an age-related degenerative process without an identifiable preceding pathology, whereas secondary hip osteoarthritis arises from specific underlying conditions or antecedent trauma (e.g., prior fractures, dysplasia, Perthes disease, or repetitive high-load stress).

Clinical Practice Guideline (Grade A) diagnostic criteria for Hip OA

Age $> 50\,\text{years}$, moderate anterior or lateral hip pain during weight-bearing activities (worse at rest or during sleep), morning stiffness lasting $< 1\,\text{hour}$, active hip flexion and internal rotation restricted by $\ge 15^\circ$ compared to the contralateral side, pain provoked by passive internal rotation, and passive internal rotation $< 25^\circ$.

Five clinical items in Sutlive's clinical prediction rule (CPR) for Hip OA

1. Hip pain with squatting; 2. Lateral hip pain with active flexion; 3. Lateral hip pain with the scour test; 4. Hip pain with active extension; 5. Passive internal rotation $\le 25^\circ$.

Diagnostic utility of Sutlive's CPR for Hip OA

The presence of $\ge 3$ out of $5$ positive tests yields a positive likelihood ratio of $5.2$ (moderate diagnostic evidence), while $\ge 4$ out of $5$ positive tests yields a positive likelihood ratio of $24.3$ (strong diagnostic evidence to confirm hip OA).

Intracapsular vs. Extracapsular hip fractures

Intracapsular fractures occur proximal to the capsular attachment at the femoral neck ($53\%$ of hip fractures) and carry high vulnerability to avascular necrosis due to retinacular vascular disruption; extracapsular fractures occur outside the joint capsule and encompass intertrochanteric ($35\%$) and subtrochanteric ($10\%$) fractures.

Garden classification system for femoral neck fractures

Type I: Incomplete or impacted fracture; Type II: Complete non-displaced fracture; Type III: Complete fracture with partial displacement; Type IV: Complete fracture with total displacement and disruption of trabecular alignment.

Fragility hip fractures primary etiology and setting

Low-energy falls occurring inside the home account for $90\%$ of all fragility hip fractures in older adults.

Paget's disease of the bone

The second most common metabolic bone disorder after osteoporosis, driven by hyperactive osteoclastic resorption followed by chaotic, uncontrolled osteoblastic deposition that replaces normal marrow with structurally fragile, disorganized fibrous collagen.

Sclerosis

The abnormal hardening or stiffening of body tissues or organs, typically resulting from the replacement of normal anatomical tissue with dense connective scar tissue.

Radiographic progression stages of femoral head avascular necrosis (AVN)

Stage 1: Normal radiograph or mild osteopenia; Stage 2: Sclerosis of the superior femoral head and subchondral cyst formation; Stage 3: Subchondral bone collapse (crescent sign) with joint space narrowing; Stage 4: Progressive collapse with trabecular destruction; Stage 5: Advanced degenerative joint disease involving both femoral and acetabular articular surfaces.

Primary etiology of non-traumatic femoral head AVN

Systemic corticosteroid use and excessive alcohol consumption, which together account for approximately $80\%$ of non-traumatic avascular necrosis presentations.

High-energy vs. Low-energy femoral shaft trauma

High-energy trauma involves high-magnitude axial loading (e.g., motor vehicle collisions or falls from height) typical in younger patients; low-energy trauma involves minor loading on structurally compromised bone (e.g., severe osteoporosis) resulting in insufficiency fractures in older populations.

Compound (open) fracture

A severe fracture subtype in which displaced bone fragments penetrate the skin and soft-tissue envelope, creating direct communication between the external environment and the fracture hematoma.

Comminution

A structural fracture state in which bone is shattered or broken into multiple small distinct fragments.

Emergent surgical window for femoral shaft fractures

Operative reduction and stabilization within $24\text{--}48\,\text{hours}$ post-injury to prevent life-threatening systemic polytrauma complications (e.g., fat embolism syndrome, respiratory failure).

Posterior hip dislocation mechanism and clinical presentation

Caused by axial loading on a flexed, adducted hip ($85\%$ of all dislocations); presents clinically with ipsilateral limb shortening, flexion, adduction, and internal rotation.

Anterior hip dislocation mechanism and clinical presentation

Caused by forceful extension, abduction, and external rotation ($10\%$ of dislocations); presents clinically with limb abduction, external rotation, and variable flexion without significant limb shortening.

Conventional post-arthroplasty movement precautions for posterior THR

Avoid hip adduction past anatomical neutral (do not cross legs or ankles), avoid hip flexion $> 90^\circ$, and avoid active or passive internal hip rotation.