7.1 Joint Derangement, Hypermobility and Hypomobility

7.1 Joint Derangement, Hypermobility and Hypomobility

Quick Answer: Treat joint problems by matching mobility status to load capacity. Screen for true mechanical derangement (locking, loose body, instability) versus stiffness or symptomatic hypermobility. Protect unstable or recently injured joints, restore controlled motion and strength, and escalate when locking persists, neurology worsens, or red flags appear. For osteoarthritis-type presentations, prioritise education and progressive exercise over passive-only care or premature imaging.

Musculoskeletal joint presentations are common across private practice, sports, emergency discharge, community, and subacute settings in Australian physiotherapy. The APC Written Assessment expects entry-level clinical reasoning: classify the problem on a mobility spectrum, detect mechanical derangement that needs medical imaging or surgical pathways, and build a safe progressive plan rather than treating every stiff or “clicky” joint the same way.

Framing Joint Problems for the Exam

Think in three overlapping layers:

1. Tissue and structure — capsule, cartilage, meniscus/labrum, bone surfaces, loose bodies, ligaments providing passive restraint.
2. Mobility status — hypomobile (restricted), normal, hypermobile (excess range), or unstable (excess motion with poor control and symptom provocation).
3. Load capacity and irritability — can the joint and surrounding muscles tolerate the person’s work, sport, and daily demands without flare or giving way?

A person may have high passive range yet poor control (symptomatic hypermobility), or low range with high irritability (acute locked or inflamed joint). Management follows the combination, not a single label.

Joint Derangement and Loose Bodies

Derangement in clinical teaching often means an intra-articular mechanical disturbance that changes how the joint surfaces move—classically intermittent locking, catching, or a block to motion that may alter with position or a self-manipulation. Causes include loose osteochondral fragments, displaced meniscal or labral tissue, intra-articular free bodies after injury or osteochondritis dissecans, and sometimes severe degenerative debris in advanced osteoarthritis.

Typical history clues

• Sudden “something moved” sensation with true locking (cannot unlock actively) versus momentary catching that self-resolves.
• Recurrent giving way with swelling after sport or awkward loading.
• Episodes of full function between mechanical events (classic for mobile loose body).
• Prior trauma, osteochondral injury, or known degenerative joint disease.

Examination priorities

• Observe resting position, effusion, and willingness to move.
• Active and passive range: is there a hard mechanical block in one direction with relatively free motion elsewhere?
• Special tests for meniscal/labral pathology are supportive but not perfect; interpret clusters, not single tests.
• Neurovascular screen when trauma, dislocation risk, or limb-threatening features are present.
• Compare with the contralateral side for baseline mobility and control.

Physiotherapy role versus medical pathway

Physiotherapists do not “manipulate out” a confirmed free body as definitive care. If history and exam strongly suggest intermittent locking from a loose body or displaced intra-articular tissue, protect the joint, avoid forced end-range techniques into the block, document findings, and facilitate timely medical or orthopaedic review with appropriate imaging as per local pathways. Between episodes, maintain safe strength and adjacent joint capacity without repeatedly provoking locking.

Red-flag and urgent pathways include inability to weight bear after trauma, suspected fracture or dislocation, hot swollen joint with systemic features (septic arthritis concern), or progressive neurovascular compromise.

Hypermobility: Flexibility, Symptoms and Instability

Hypermobility means range of motion greater than expected for age, sex, and population norms. It sits on a continuum:

Assessment ideas (entry-level)

• Symptom map: which joints hurt or feel unstable, and under what loads?
• Screening tools such as the Beighton score can support generalised hypermobility discussion but do not alone diagnose a systemic syndrome or dictate treatment intensity.
• Test quality of control near end range: scapular control in overhead athletes, single-leg stance and landing in lower limb hypermobility, deep squat or lunge control.
• Screen for traumatic instability history (e.g., shoulder dislocation) separately from constitutional flexibility.
• Consider fatigue, deconditioning, and fear of movement as modifiers of performance.

Management principles

1. Educate that hypermobility is not automatically “weak tissue forever”—capacity can improve with progressive training.
2. Prioritise motor control and strength through available, non-provocative ranges first; expand range only when control follows.
3. Avoid excessive passive stretching into already excessive ranges when symptoms relate to lack of control rather than tightness.
4. Stage return to sport/work with criteria (pain response, control drills, task-specific load) rather than calendar days alone.
5. Escalate recurrent traumatic dislocations, progressive neurological signs, or suspected connective tissue disorder features that need medical assessment beyond physiotherapy scope for diagnosis.

APC vignettes often contrast a dancer or gymnast with high range and good control against a person with recurrent shoulder subluxations and poor cuff/scapular timing. The first needs load planning and capacity; the second needs protection, progressive stability work, and possible orthopaedic input if recurrent.

Hypomobility and Joint Dysfunction

Hypomobility is restricted accessory or physiological motion relative to need. Causes include post-immobilisation stiffness, capsular tightness after injury or surgery, osteoarthritis-related osteophytes and soft-tissue adaptation, protective muscle guarding, and prolonged under-use.

Joint dysfunction (clinical language varies) usually means a regional impairment of joint motion and related neuromuscular control that contributes to pain or activity limitation—without implying a single dramatic derangement event. Reasoning should still exclude serious pathology and true mechanical locking.

Assessment

• Active range versus passive range and end-feel (firm capsular versus empty/pain-inhibited versus bony block).
• Comparable sign: the movement that reproduces the patient’s problem.
• Adjacent segment compensation (e.g., lumbar extension substituting for stiff hip extension).
• Strength and motor control within the available range—stiffness plus weakness is common after casting or fear-avoidance.
• Irritability: how easily symptoms flare and how long they settle.

Treatment reasoning

• Match technique intensity to irritability: low-grade mobilisation and active-assisted motion when irritable; progress amplitude and load as symptoms settle.
• Combine manual techniques (when indicated and consented) with active exercise—passive-only care rarely rebuilds function for the APC standard.
• Restore functional patterns early: sit-to-stand, gait, reach, stair negotiation—not isolated range numbers alone.
• Respect precautions after fracture fixation, acute soft-tissue repair, or unstable joints; hypomobility treatment is inappropriate when the joint should be protected.

Do not force through a hard mechanical block suggestive of loose body, severe bony constraint, or acute locked knee/elbow without medical pathway. Do not mobilise aggressively into a direction that reproduces frank instability or neurological symptoms.

Osteoarthritis: Exam Reasoning Link (Not a Full OA Textbook)

Osteoarthritis (OA) commonly appears in APC-style cases as gradual joint pain, morning stiffness that eases with movement, activity-related ache, and reduced participation in older adults or post-injury joints. For exam reasoning:

• First-line care emphasises education, weight management discussion where relevant, progressive strengthening and aerobic activity, and activity modification—not rest forever or passive modalities alone.
• Imaging is not required to start physiotherapy for typical mechanical OA presentations without red flags; X-ray changes correlate imperfectly with pain.
• Flare management uses temporary load reduction, maintain gentle movement, then rebuild capacity—similar load logic to other MSK problems.
• Surgical pathways (e.g., arthroplasty discussion) arise when pain and function remain unacceptable despite adequate non-operative care, or when mechanical symptoms suggest concurrent derangement needing specialist opinion.

Link OA to this section by asking: Is the dominant problem stiffness (hypomobility), intermittent mechanical locking (derangement/debris), or giving way from weakness and poor control? Each steers exercise design and referral timing differently.

When to Refer for Imaging or Surgery

Use clusters, not single findings:

Imaging / medical review sooner when:

• Trauma with inability to weight bear or use the limb; Ottawa-type decision rules positive where applicable.
• True locking that does not unlock, or recurrent locking with effusion.
• Suspected fracture, dislocation, osteochondral injury, or avascular necrosis risk features.
• Hot joint, fever, or systemically unwell patient (infection pathway).
• Night pain with constitutional symptoms, cancer history, or progressive unexplained deterioration.
• Progressive neurological deficit related to the joint region (e.g., post-dislocation nerve injury).

Surgical opinion more likely when:

• Confirmed loose body or displaced meniscal/labral pathology with mechanical symptoms not settling with appropriate protection and rehab.
• Recurrent traumatic instability after structured physiotherapy and activity modification.
• End-stage joint disease with failed comprehensive non-operative care and unacceptable function.

Continue physiotherapy-led care when:

• Non-traumatic stiffness or deconditioning dominates.
• Symptomatic hypermobility without recurrent traumatic dislocation.
• Typical OA pattern without red flags, with room to improve strength and participation.

Putting It Together for APC Cases

A strong answer usually: (1) screens safety and mechanical red flags, (2) classifies mobility and irritability, (3) sets a short-term protection or load plan, (4) prescribes progressive active rehabilitation with clear criteria, and (5) states when imaging or medical referral is required. Avoid both extremes—endless passive “cracking” without capacity building, and premature surgical referral for uncomplicated stiffness or OA-type pain that has never had a proper exercise trial.

Document comparable signs, objective range and strength, patient goals, and agreed review points. Shared decision-making matters: explain why temporary activity modification protects a loose body pathway, or why strength training is the main OA treatment rather than “waiting for a scan.”

Key Clinical Pitfalls

• Mistaking momentary clicking for true locking and over-referring—or under-referring true mechanical blocks.
• Stretching hypermobile patients harder because they “feel tight” when they actually lack control.
• Aggressive mobilisation of irritable or potentially unstable joints.
• Treating OA only with heat and rest without progressive loading.
• Ignoring yellow flags (fear, low expectation of recovery) that amplify disability around joint pain.

Decision Table for Common Exam Options

Australian-Style Case Reasoning

Case A — intermittent knee locking (community football): 22-year-old reports three episodes of true inability to extend after twisting, free motion between episodes, small recurrent effusions, no fever. Plan: treat as possible loose body/displaced meniscal tissue; protect forced end-range and cutting; maintain hip/quad capacity safely; facilitate timely GP/orthopaedic imaging pathway; do not force “unlocking” stretches as definitive care.

Case B — symptomatic hypermobility (recreational gymnast): global high range, Beighton elevated, shoulder and knee ache after long training blocks, no traumatic dislocation. Plan: educate capacity can improve; prioritise control and strength near end range; reduce passive stretching volume into already excessive ranges; load-manage training spikes; review if traumatic instability appears.

Case C — knee OA (older adult, private practice): activity-related medial knee pain, morning stiffness <30 minutes, reduced quads, no red flags, wants MRI before any exercise. Plan: explain imaging is not a prerequisite to start care for typical OA; education, progressive strengthening, activity modification, weight-management discussion where relevant, functional goals; safety-net for red flags; escalate if mechanical locking develops or non-op care fails after an adequate trial.

Case D — post-sling shoulder stiffness: stable injury, medical clearance for progressive motion, limited elevation and ER, weak cuff, fearful. Plan: graded active-assisted motion matched to irritability; cuff/scapular control; avoid aggressive end-range into apprehension if instability history still relevant; combine manual techniques (consented) with active exercise, not passive-only care.

Integrating with Adjacent Chapters

Joint derangement reasoning sits between soft-tissue chapters (muscle, ligament, tendon) and the fracture/dislocation emergencies in the next section. If the vignette includes deformity, inability to move the joint after trauma, or neurovascular threat, shift immediately to dislocation/fracture pathways rather than “mobilise the stiff joint.” If paraesthesia and myotomal weakness dominate, open the peripheral nerve/radiculopathy lens in Section 7.3.

Self-check before the next section

1. Can I distinguish true mechanical locking from clicking or pain inhibition?
2. Can I separate constitutional hypermobility, symptomatic hypermobility, and structural instability?
3. Can I dose hypomobility treatment to irritability and precautions?
4. Can I justify exercise-first OA care without mandatory early imaging?
5. Can I name clear imaging/surgical referral thresholds?

If yes, you are ready for fractures, dislocations, and subluxations—where medical reduction scope and weight-bearing precautions become non-negotiable.