Foundations of Biomechanics & NeuroMusculoSkeletal Management – Week 2 Diagnostic Decision-Making

Course & Session Context

• Course: Foundations of Biomechanics & NeuroMusculoSkeletal Management (DPT 6150)
• Week 2 focus: Intro to Diagnosis (DX) & Differential Decision-Making
• Agenda covered six major themes:
  • Chronic Pain Syndrome (Central Sensitization)
  • Impairment-Based Diagnosis
  • Clinical Practice Guidelines (CPGs)
  • Treatment-Based Classification (TBC)
  • Pathoanatomical/Structural/Medical DX
  • Acute Injury Management

Definition of Diagnosis (House of Delegates, “DX by PTs”)

• A diagnosis = label that groups a cluster of signs & symptoms commonly linked to a classification, disorder, syndrome, or category of impairments in:
  • Body structures & functions
  • Activity limitations
  • Participation restrictions

Where Diagnosis Occurs in Patient Management

1. Patient Interview (incl. patient-reported outcome measures)
2. Observation (global posture / movement)
3. Triage & Differential DX
   • Sensitive screens to rule out non-related or serious pathology
   • Neuro screen, cognitive screen, functional screen, UQS/LQS
4. Motion Tests (AROM, PROM, accessory motion)
5. Muscle Performance Testing
6. Special Tests
7. Palpation
8. Physical Performance Measures

➡ First-Order Decision: Treat? Treat + Refer? Refer?

Clinical Reasoning Framework (Biopsychosocial Model)

• TRIAGE → Rule out red flags (cancer, infection, fracture) & visceral/non-mechanical sources.
• If Neuromusculoskeletal (NMS):
  • Identify affected & associated regions; evaluate SINSS (Severity, Irritability, Nature, Stage, Stability).
  • Determine dominant pain mechanism, diagnostic classifications & impairments.
• Psychosocial Contributors:
  • Lifestyle, work demands, fear, depression, anxiety → heightened relevance for Chronic Pain Syndrome / Central Sensitization.

Six Diagnostic Classification Systems (Integrated – none superior, none used alone)

1. Pain Mechanism Classification
2. Impairment-Based Diagnosis (links impairment to functional limitation)
3. Clinical Practice Guidelines (Orthopaedic Academy APTA)
4. Treatment-Based Classification (subgroups for LBP/Neck)
5. Structural / Pathoanatomical Medical Diagnosis
6. Acute Injury Classification

1. Pain Mechanism Classification (Smart 2012)

• Classifies pain by dominant neurophysiological generator/maintainer.

a) Nociceptive Pain

• Activation of peripheral nociceptors (chemical, mechanical, thermal stimuli).
• Typical with acute NMS injury or post-op.

b) Peripheral Neuropathic Pain

• Lesion/dysfunction in peripheral nerve, DRG, or nerve root (trauma, compression, inflammation, ischemia).
• Presents with nerve-root entrapment or distal peripheral nerve symptoms.

c) Central Sensitization Pain (Chronic Pain Syndrome)

• Amplified CNS signaling → hypersensitivity, expanded receptive fields, lowered thresholds.
• “Danger signals” magnified: more intense & longer lasting.

2. Impairment-Based Diagnosis

• Identify relevant impairments (contributing factors) that directly limit functional activities.
• Treat impairment → Re-assess function.

Common NMS Impairments

• Sensory: pain, hypoesthesia, proprioceptive loss
• Motor: poor control, weakness, altered muscle quality
• ROM: joint hypomobility, soft-tissue restrictions
• Ergonomics & biomechanics
• Aerobic capacity / endurance
• Cognitive & emotional factors (fear, motivation, stress)
• Circulation & respiration impairments

Difficulty Moving? Ask WHY

1. Pain
2. Weakness / Motor Control deficit
3. Decreased ROM
   • Joint hypomobility → assess with PROM / PAM
   • Soft-tissue hypomobility: contracture, adhesions, trigger points

3. Clinical Practice Guidelines (CPGs)

• Published by APTA Sections/Academies; free to members.
• Provide graded evidence for: examination, diagnostic categories, prognosis, interventions, outcomes.

Pros:

• Summarize large research bodies → graded evidence
• Offer exam & treatment recommendations

Cons:

• Limited patient specificity; exclude clinician experience & patient values (other EBP pillars)
• High inclusion threshold may omit emerging evidence

Example – LBP CPG Subgroups:

1. LBP w/ Mobility Deficits (soft tissue, joint, nerve)
2. LBP w/ Movement Coordination Deficits (motor control)
3. LBP w/ Muscle Performance Deficits (strength/endurance/power)

4. Treatment-Based Classification (TBC) – LBP Focus

• Developed pre-CPG era to move beyond “all LBP = same”.
• Clusters signs & symptoms to match patients with most effective intervention category.
• Evidence currently for lumbar & cervical spine only.

TBC Subgroups & Key Favoring / Against Factors:

• Manipulation

• Favor: recent onset, hypomobility, \uparrow episode frequency
• Against: symptoms below knee, increasing episode frequency

• Stabilization

• Favor: younger age, + prone instability test, aberrant motions, hypermobility, \text{FABQ}_{W} < 19
• Against: no pain with spring testing, low \text{FABQ}_{PA}, SLR discrepancy > 10^{\circ}

• Specific Exercise

• Favor: directional preference (sitting vs walking), centralization with motion, peripheralization opposite direction
• Against: purely axial pain, status quo across all movements

5. Structural / Pathoanatomical Medical Diagnoses

• Pathology-based; describe structural & functional tissue changes.
• Needed for precautions / contraindications; may or may not guide treatment.
• Macrotrauma vs Microtrauma (repetitive overload, biomechanical faults).

Ligament Sprains (Grade 1\rightarrow3)

• Grade 1: painful/limited AROM & PROM same direction; no laxity; point tenderness; full WB possible.
• Grade 2: partial tear; effusion; mild laxity w/ end-feel; antalgic gait; high re-injury risk.
• Grade 3: near/complete rupture; marked laxity, no firm end-feel; possible need for surgery.

Muscle Strains

• Mild (1º): minor swelling, strong–painful resisted test, pain on passive stretch.
• Moderate (2º): partial tear; ecchymosis; weak–painful resisted test.
• Severe (3º): complete tear; severe function loss; surgical repair common.

Dislocation vs Subluxation

• Dislocation: full loss of articular relationship.
• Subluxation: partial/incomplete displacement.

Tendinopathy

• True tendinitis (active inflammation) rare & responds quickly to rest/NSAIDs.
• Chronic tendinopathy hallmark findings:
  • Overload history; pain on tendon stretch (PROM) & contraction (isometric strong–painful).
  • Treatment: staged loading → isometrics (analgesia) → slow, heavy isotonic w/ eccentric bias.

Fractures & Stress Injuries

• Healing Phases: Inflammation (days 1–6) → Reconstruction (days 7–9) → Remodeling (days 10–30+).
• Types: transverse, oblique, spiral, avulsion, compression, stress.
• Pediatric Salter–Harris (SALTR) I–V, with Types III & IV often requiring surgery.
• Bone Stress Injury spectrum:
  • Stress reaction (over-pressure)
  • Osteoporotic fx (under-pressure)

Cartilage Injuries

1. Degenerative Joint Disease (OA)
   • Joint‐space narrowing + symptoms; imaging often asymptomatic.
2. Rheumatoid Arthritis (RA)
   • Autoimmune synovial inflammation; stiffness > 60 min AM; systemic signs (fatigue, fever).
3. Osteochondritis Dissecans (OCD) / Chondromalacia – focal articular cartilage/subchondral bone lesion.

Peripheral & Central Nervous System Injury

• Radiculopathy = nerve-root lesion (LMN presentation, \downarrow DTRs).
• Myelopathy = spinal cord lesion (UMN signs, \uparrow DTRs).

Three Grades of Peripheral Nerve Injury:

1. Neuropraxia – transient block; intact axon; full recovery minutes-days.
2. Axonotmesis – axon/myelin disruption with Wallerian degeneration; connective tissue intact; months recovery.
3. Neurotmesis – complete severance; requires surgical repair; often incomplete recovery.

Compartment Syndrome

• Intracompartmental pressure → ischemia → irreversible muscle loss 4–8 hrs without fasciotomy.

6. Acute Injury Management & Intervention Progression Model (UVA–Baylor)

Stages (patient & provider responsibilities):

1. Tissue Healing / Pain Management
2. Restore Motion
3. Motor Control
4. Strength → Power → Endurance → Proprioception
5. Skilled Activity → Full Activity

• Overlay of patient behaviors (coping, compliance) & goals at every stage.

Integrated Use of Classification Systems

• Patients often fit multiple systems simultaneously; choose dominant system on Day 1 to guide initial treatment.
• Recommended workflow:
  1. Comprehensive history & interview.
  2. Triage decision (Treat? Treat+Refer? Refer?).
  3. Differential DX list → prioritize.
  4. Plan Tests & Measures that:
  • Confirm or refute working DX.
  • Identify contributing impairments.

Key Take-Home Points

• No single diagnostic system is gold standard; integration yields best clinical reasoning.
• Understand pain mechanisms, impairments, guideline recommendations, treatment classifications, structural pathology, and injury acuity in tandem.
• Patient-centered approach within biopsychosocial framework remains paramount.