Foundations of Biomechanics & NeuroMusculoSkeletal Management – Diagnostic Vocabulary

Diagnosis: Definition & Scope

• House of Delegates position, “Dx by PTs”
  • Diagnosis = label that captures a cluster of signs & symptoms commonly associated with a classification, disorder/syndrome, or category of impairments in body structures & function, activity limitations, or participation restrictions.
  • Distinct from medical pathology; emphasizes movement-related consequences.

Differential Diagnosis (DX) Is Everywhere in the Encounter

• Occurs in two primary arenas
  1. Patient interview (history & outcome measures).
  2. Tests & Measures.
• Michael Reiman’s 8-step sequence (Fig. 4.1)
  • Patient interview ➞ Observation ➞ Triage/screening ➞ Motion tests ➞ Muscle performance ➞ Special tests ➞ Palpation ➞ Physical performance.
• First-order decision after screening
  • Treat? Treat & refer? Refer?
• Patient education (Pnt Ed) & prognosis (PX) interwoven continuously.

Biopsychosocial Model & Triage

• Goal 1 – Rule out non-NMS or emergent NMS red flags
  • Cancer, infection, fracture, visceral/non-mechanical pain, or other conditions mimicking NMS disorders.
• Goal 2 – If NMS:
  • Identify involved & associated regions.
  • Evaluate SINSS (Severity, Irritability, Nature, Stage, Stability).
  • Determine dominant pain mechanism, diagnostic classification(s), & impairments.
• Psychosocial contributors
  • Lifestyle, work demands, prior experiences, fear, depression, anxiety—especially relevant for Chronic Pain Syndrome / Central Sensitization.
  • Source: Murphy & Hurwitz 2007 theoretical model (spinal pain).

Six Diagnostic Classification Systems (Within Biopsychosocial Model)

Key premise: No single system is superior or used in isolation—most patients map onto multiple systems simultaneously.

1. Pain Mechanism Classification.
2. Impairment-Based Diagnosis.
3. Clinical Practice Guidelines (CPGs).
4. Treatment-Based Classification (TBC).
5. Structural / Pathoanatomical (medical) diagnosis.
6. Acute injury classification.

1 – Pain Mechanism Classification (Smart 2012)

• Classifies pain by neurophysiological generator/maintainer.
• Nociceptive Pain
  • Peripheral nociceptor activation (chemical, mechanical, thermal).
  • Often acute NMS injury or post-operative context.
• Peripheral Neuropathic Pain
  • Lesion/dysfunction of peripheral nerve, DRG, or nerve root (trauma, compression, inflammation, ischemia).
  • Classic example: radiculopathy, nerve entrapment.
• Central Sensitization Pain (aka Chronic Pain Syndrome)
  • Amplified CNS signaling, lowered thresholds, expanded receptive fields.
  • “Danger signals” magnified—longer-lasting & more intense.
  • Expect widespread pain, hypersensitivity, disproportionate to tissue status.

2 – Impairment-Based Diagnosis (IBD)

• “Relevant impairments” = contributing factors driving functional limitations.
• Workflow
  • Identify impairments → Treat impairments → Re-assess function.
• Common NMS impairment buckets
  • Sensory (pain, proprioceptive loss), Motor control/strength, ROM limitations, Aerobic endurance, Ergonomics, Cognition, Circulation, Respiration.
• Difficulty Moving? Ask WHY (determine root impairment)
  1. Pain.
  2. Weakness / decreased motor control.
  3. ROM restriction (joint hypomobility, soft-tissue issues).
• Testing & treatment examples
  • PROM/AROM/PAM for joint capsular tightness; joint mobilization + exercise if positive.
  • Trigger point palpation & soft-tissue techniques for myofascial restrictions.

3 – Clinical Practice Guidelines (APTA Orthopaedic Academy)

• Compile current best evidence ➞ present graded recommendations for:
  • Examination, DX classification, prognosis, interventions, outcomes.
• Pros
  • Summarize voluminous research; quality grading; guide clinician–patient decisions.
• Cons
  • Do not individualize to the person in front of you.
  • Evidence threshold excludes emerging or low-level data; ignores clinician experience & patient values.
• LBP CPG Example (Diagnostic Subgroups)
  1. LBP with Mobility Deficits.
  2. LBP with Movement Coordination Deficits.
  3. LBP with Muscle Performance Deficits.

4 – Treatment-Based Classification (TBC)

• Historical precursor to CPGs; initially for LBP, then neck.
• Aim: subgroup patients likely to benefit from specific treatment approaches.
• LBP Subgroups & Key Factors (Fritz 2007/Brennan 2006)
  • Manipulation → recent onset, hypomobility, no distal sx, etc.
  • Stabilization → younger, +prone instability, aberrant motions, hypermobility.
  • Specific exercise (directional preference) → centralization, motion-specific relief.
  • (Traction subgroup in earlier versions.)

5 – Structural / Pathoanatomical Medical Diagnosis

• Focus on tissue pathology: “what structure is damaged?”
• Provides precautions, contraindications, partial prognosis but often poor guidance for PT intervention selection.
• Common pathologies introduced:
  • Ligament sprains.
  • Muscle strains.
  • Dislocations / subluxations.
  • Tendinopathies.
  • Fracture / stress fracture.
  • Cartilage injuries (OA, RA, OCD).
  • Nerve injuries.
• Macrotrauma vs Microtrauma (MOI)
  • Macro: single traumatic event.
  • Micro: repetitive loading, over-training, poor mechanics.

Ligamentous Sprain Grading

• Grade 1: painful but stable, minimal hemorrhage; full WB possible.
• Grade 2: partial tear, mild laxity with firm endpoint, antalgic gait; higher re-injury risk.
• Grade 3: complete rupture, marked laxity, surgical consideration.

Muscle Strain (Sprain-to-Tear Continuum)

• Mild (1°): local tenderness; strong-painful resisted test; pain on stretch.
• Moderate (2°): partial tear, weakness, ecchymosis, weak-painful resist.
• Severe (3°): complete tear; severe dysfunction; surgery often required.

Dislocation vs Subluxation

• Dislocation = complete loss of anatomical relationship.
• Subluxation = partial/incomplete displacement.

Tendinopathy

• Tendinitis (true inflammation) = rare; should respond quickly to rest/NSAIDs.
• Chronic overload tendinopathy hallmarks
  • Pain on passive stretch & active loading.
  • Strong-painful isometric test.
  • Tx: isometrics for analgesia ➞ slow heavy loading with eccentric bias (Cook model).

Fracture / Bone Stress Injury

• Healing phases: Inflammation (days 1-6) ➞ Reconstruction (days 7-9) ➞ Remodeling (days 10-30 +).
• Types: transverse, oblique, spiral, comminuted, avulsion, compression, stress.
• Pediatric Salter-Harris I–V (SALTR mnemonic: Straight, Above, Lower, Through, Rammed).
• Bone stress injury continuum: stress reaction (excess load) vs osteoporotic fx (insufficient load).
• Radiographic review basics: Alignment, Bone, Cartilage (“ABC”).

Cartilage Injuries

1. Osteoarthritis (OA / DJD)
   • Thinning, fissures, osteophytes; symptomatic
   • Primary (idiopathic) vs Secondary (post-trauma).
   • Impairments: pain, stiffness <30 min AM, crepitus, loss ROM, atrophy.
2. Rheumatoid Arthritis (RA)
   • Autoimmune synovitis; prolonged stiffness >60 min AM; systemic S/S (fatigue, low-grade fever, weight loss, nodules).
3. Osteochondritis Dissecans (OCD / chondromalacia)
   • Localized subchondral bone & cartilage lesion (e.g., femoral condyle).

Nerve Injuries

• UMN vs LMN distinctions
  • Radiculopathy (nerve root) = LMN; hyporeflexia.
  • Myelopathy (cord) = UMN; hyperreflexia.
• Peripheral nerve injury mechanisms: pressure, traction, friction, anoxia, laceration, thermal, electrical.
• Combined motor + sensory loss signals nerve compromise.
• Seddon / Sunderland Grades
  1. Neuropraxia – transient block; no Wallerian degeneration; full recovery days–weeks.
  2. Axonotmesis – axon/myelin disrupted; connective tissue intact; Wallerian degeneration; recovery months.
  3. Neurotmesis – complete severance incl. connective tissue; requires surgery; often incomplete recovery.
• Compartment Syndrome
  • Intracompartmental pressure → nerve ischemia; irreversible muscle loss in 4\text{–}8 h; emergent fasciotomy indicated.

6 – Acute Injury Classification & Intervention Progression (UVA–Baylor model)

• Stages: Pain management → Motion → Motor control → Strength → Endurance → Power → Proprioception → Full activity.
• Intertwined responsibilities
  1. Tissue healing status.
  2. Functional abilities.
  3. Patient goals.
  4. Patient behaviors (coping, compliance).

Integrated Use of Multiple Systems

• Patients typically span more than one classification; clinician determines which is dominant on Day