📋 Key Information Summary
- Knee pain is one of the most common musculoskeletal presentations in Australian primary care, accounting for approximately 3–4% of all GP consultations nationally.
- A systematic diagnostic model using anatomical location (anterior, medial, lateral, posterior) narrows the differential and guides targeted examination and imaging.
- Patellofemoral pain syndrome (PFPS) is the most common cause of anterior knee pain, particularly in active adolescents and young adults; management is predominantly physiotherapy-based.
- Medial meniscal tears are more common than lateral; acute traumatic tears in younger patients often require arthroscopic repair, while degenerative tears in those ≥40 years are managed conservatively first.
- Anterior cruciate ligament (ACL) rupture presents with acute haemarthrosis, a positive Lachman test, and a pivot-shift mechanism; MRI confirmation and early orthopaedic referral are indicated for surgical candidates.
- An acute traumatic haemarthrosis (swelling within 4 hours of injury) mandates urgent assessment — ACL rupture, tibial plateau fracture, or patellar dislocation are the most common causes.
- The Ottawa Knee Rules reliably exclude clinically significant fractures in adults; knee X-rays are not required if the patient can weight-bear four steps, has no isolated patellar tenderness, and no effusion.
- MRI is the investigation of choice for internal derangement (meniscal tears, ligament injuries, chondral defects); Medicare rebate requires a valid referral and relevant clinical indication (MBS items 63xxx series).
- First-line analgesia is paracetamol ± short-course NSAIDs; opioids should be avoided for chronic knee pain. Intra-articular corticosteroid injections provide short-term relief in osteoarthritis flares.
- Loose bodies within the knee may cause intermittent locking, catching, and sudden giving way; diagnosis is confirmed on MRI or CT arthrography, and arthroscopic removal is definitive treatment.
- Aboriginal and Torres Strait Islander Australians experience disproportionately higher rates of musculoskeletal disease and delayed access to specialist orthopaedic care, particularly in remote communities.
- Paediatric knee pain must always consider Osgood-Schlatter disease, osteochondritis dissecans, and slipped capital femoral epiphysis (referred pain); intra-articular corticosteroids are contraindicated in children.
Introduction & Australian Epidemiology
Knee pain is one of the most prevalent musculoskeletal complaints presenting to Australian general practice, sports medicine clinics, and emergency departments. The knee is the largest synovial joint in the body and is uniquely vulnerable to acute traumatic injury, overuse syndromes, and degenerative disease. An estimated 2.1 million Australians live with chronic knee conditions, and the burden is projected to increase with population ageing and rising obesity rates.
In Australian primary care, knee pain accounts for approximately 3–4% of all encounters (Bettering the Evaluation and Care of Health [BEACH] data). The most common diagnoses include osteoarthritis (OA), patellofemoral pain syndrome (PFPS), meniscal tears, and ligament injuries. OA of the knee affects roughly 10% of Australians aged ≥45 years and is a leading cause of disability in Aboriginal and Torres Strait Islander populations.
Acute sports-related knee injuries — particularly ACL rupture and meniscal tears — are disproportionately common in Australian Rules football, rugby league, netball, and soccer. The Australian Institute of Health and Welfare (AIHW) reports that knee injuries account for approximately 20% of all sport-related hospital presentations. Young males aged 15–34 years represent the highest-risk demographic for traumatic ligamentous injury.
A structured approach to the painful knee begins with accurate anatomical localisation of pain, followed by targeted history (mechanism, onset, aggravating factors), focused physical examination, and judicious use of imaging. This article presents a diagnostic model, detailed analysis of pain by compartment, and evidence-based management of the most clinically important knee conditions in Australian practice.
Painful Knee Diagnostic Model
An efficient diagnostic approach to the painful knee requires integration of history (mechanism, onset, pain character), physical examination findings, and targeted investigations. The following stepwise model is recommended for Australian primary care and emergency settings.
1
Characterise the Onset & Mechanism
Acute traumatic (twist, direct blow, hyperextension) vs. insidious onset vs. acute-on-chronic flare. Document the exact mechanism — pivot-shift injury suggests ACL; valgus blow suggests MCL; squatting/twisting suggests meniscal.
2
Localise Pain Anatomically
Anterior (patellofemoral, patellar tendon, prepatellar bursa), medial (MCL, medial meniscus, pes anserine), lateral (LCL, ITB, lateral meniscus), posterior (Baker's cyst, PCL, popliteal pathology). Use the compartment model below.
3
Identify Red Flags
Acute traumatic haemarthrosis (swelling <4 hours), inability to weight-bear, gross deformity, open injury, neurovascular compromise, septic arthritis (fever, hot knee, systemic illness), suspected fracture.
4
Apply Ottawa Knee Rules
X-ray required if age ≥55, isolated patellar tenderness, fibular head tenderness, inability to flex to 90°, inability to weight-bear four steps immediately and in ED. Sensitivity >98% for clinically significant fractures.
5
Perform Targeted Examination
Effusion (patellar tap, sweep test), ROM, special tests — Lachman (ACL), McMurray (meniscus), valgus/varus stress (collateral ligaments), Clarke's test (PFPS), patellar apprehension (instability).
6
Select Investigations
X-ray if fracture suspected. MRI for suspected internal derangement, ligament injury, or unresolved symptoms >6 weeks. Ultrasound for superficial soft-tissue pathology (bursitis, tendinopathy). FBC/CRP/ESR if septic arthritis suspected.
Red flag — Acute traumatic haemarthrosis: Rapid swelling within 4 hours of injury indicates intra-articular bleeding. The most common causes are ACL rupture (70%), tibial plateau fracture, patellar dislocation, and meniscal tear with peripheral tear. Urgent orthopaedic assessment is required.
Red flag — Septic arthritis: Consider in any acutely hot, swollen, painful knee — especially in immunocompromised patients, those with prosthetic joints, or after recent intra-articular injection. Urgent aspiration (cell count, Gram stain, culture) and empirical IV antibiotics are required. Do not delay for imaging.
Anterior / Lateral / Medial Knee Pain Causes
Anterior Knee Pain
Anterior knee pain is the most common regional knee complaint and encompasses several distinct pathologies. A systematic approach is essential.
| Condition | Epidemiology | Key Features | First-Line Management |
|---|---|---|---|
| Patellofemoral Pain Syndrome (PFPS) | Most common cause of anterior knee pain; peak incidence 15–30 years; 2:1 female predominance | Diffuse anterior/peripatellar pain; worse with stairs, squatting, prolonged sitting ("movie-goer's sign"); no true locking | Physiotherapy (vastus medialis oblique strengthening, hip abductor strengthening), activity modification, taping (McConnell technique) |
| Patellar Tendinopathy (Jumper's Knee) | Common in jumping athletes (basketball, volleyball, Australian Rules football); peak 16–35 years | Localised inferior pole patellar pain; palpable tenderness at inferior pole; pain with loading (jumping, landing) | Eccentric strengthening programme (decline squats), load management, isometric loading for pain relief |
| Prepatellar Bursitis ("Housemaid's Knee") | Associated with kneeling occupations (trades, flooring, cleaning) | Fluctuant swelling anterior to patella; may be painful if infected; cellulitis overlying the bursa suggests septic bursitis | Knee pads, avoidance of kneeling, aspiration if tense; oral antibiotics (flucloxacillin 500 mg QID PO for 7–10 days) if septic |
| Osteochondritis Dissecans (OCD) | Adolescents and young adults; M:F ratio 3:1; medial femoral condyle most common | Vague anterior knee pain, intermittent effusion, possible mechanical symptoms (catching/locking) if fragment unstable | MRI to assess fragment stability; conservative for stable lesions (activity restriction, physio); arthroscopic fixation if unstable |
| Osgood-Schlatter Disease | Active children aged 10–15 years (boys > girls); bilateral in 25–50% | Pain and swelling at tibial tuberosity; worse with running, jumping, kneeling; self-limiting | Activity modification, ice, NSAIDs (ibuprofen 200–400 mg TDS PRN), physiotherapy; reassurance — resolves with skeletal maturity |
Medial Knee Pain
| Condition | Key Features | Management |
|---|---|---|
| Medial Meniscal Tear | Medial joint line tenderness; positive McMurray test; pain with deep squatting; intermittent locking/catching | Conservative (physiotherapy, NSAIDs) for degenerative tears; arthroscopic surgery for mechanical symptoms or failed conservative management |
| MCL Injury | Valgus stress injury; medial pain and tenderness over MCL; valgus laxity at 30° flexion; usually grade I–II | Bracing, early ROM, physiotherapy; most heal without surgery; grade III + multiligament injury requires orthopaedic referral |
| Pes Anserine Bursitis | Medial proximal tibial pain; tenderness 3–5 cm below joint line anteromedially; common in overweight middle-aged women, runners | Activity modification, ice, NSAIDs, physiotherapy (hamstring stretching); corticosteroid injection if refractory |
| Medial Compartment OA | Progressive medial pain; morning stiffness <30 min; varus deformity; medial joint line tenderness; crepitus | Weight loss, exercise, paracetamol, NSAIDs, intra-articular corticosteroid injection, unicompartmental or total knee replacement if severe |
Lateral Knee Pain
| Condition | Key Features | Management |
|---|---|---|
| Iliotibial Band (ITB) Syndrome | Lateral knee pain in runners/cyclists; pain at or just above lateral femoral epicondyle; worse with running downhill; Noble compression test positive | Activity modification, foam rolling, hip abductor strengthening, stretching, graduated return to running |
| Lateral Meniscal Tear | Less common than medial; lateral joint line tenderness; positive McMurray; may occur with discoid meniscus (paediatric) | Conservative initially; arthroscopic surgery if persistent mechanical symptoms |
| LCL Injury | Varus stress injury; lateral pain; varus laxity at 30° flexion; often associated with posterolateral corner injury | Urgent orthopaedic referral if complete; often requires surgical repair as LCL has poor intrinsic healing |
| Lateral Compartment OA | Less common than medial OA; lateral pain; valgus deformity; associated with previous meniscectomy | Same as medial OA management pathway; orthopaedic referral for surgical planning |
Meniscal Tears & Ligament Injuries
Meniscal Tears
The menisci are C-shaped fibrocartilaginous structures that distribute load, absorb shock, and improve congruency of the tibiofemoral joint. The medial meniscus is attached to the MCL and is less mobile, making it more susceptible to injury. Meniscal tears are classified by aetiology (traumatic vs. degenerative), morphology (bucket-handle, horizontal, radial, complex), and vascularity (red-red, red-white, white-white zones).
Stable / Minor
Degenerative Tear
Age ≥40, insidious onset, no discrete injury, small tear on MRI, no mechanical symptoms, preserved ROM.
Setting: GP / Physiotherapy
Moderate
Traumatic Tear — No Locking
Acute injury, joint line tenderness, positive McMurray, effusion, but full extension possible and no true mechanical locking.
Setting: GP + Sports Medicine / Orthopaedic referral
Severe
Locked Knee (Bucket-Handle Tear)
Acute injury with inability to fully extend the knee (10–30° block to extension), large effusion, severe pain. Displaced meniscal fragment in intercondylar notch.
Setting: Urgent orthopaedic referral — arthroscopic reduction ± repair
Locked knee: True mechanical locking (inability to fully extend) is a surgical emergency. The most common cause is a displaced bucket-handle meniscal tear. Do not confuse with pseudo-locking (quadriceps spasm). Urgent orthopaedic assessment and arthroscopic intervention within days is recommended to prevent chondral damage.
McMurray Test: The patient supine. The examiner flexes the knee fully, externally rotates the tibia, and extends the knee while applying valgus stress (tests medial meniscus). A palpable or audible click with pain is a positive test. Sensitivity 50–70%, specificity 60–80% — moderate diagnostic utility; MRI is more definitive.
Ligament Injuries
| Ligament | Mechanism | Examination | Grading & Management |
|---|---|---|---|
| ACL | Non-contact pivot shift (70%); deceleration ± cutting; hyperextension; valgus + external rotation | Lachman test (sensitivity 85–95%, most reliable); anterior drawer; pivot-shift test; acute haemarthrosis (70% of cases) | Complete tears: reconstruction (autograft hamstring/patellar tendon) recommended for young, active patients. Rehabilitation first for low-demand patients. MBS item 49542 for ACL reconstruction. |
| PCL | Dashboard injury (posterior force on flexed tibia); fall onto flexed knee; hyperflexion | Posterior drawer test; quadriceps active test; posterior sag sign; sensitivity of individual tests 40–90% | Isolated PCL: conservative (quadriceps strengthening) for most. Combined with other ligaments: surgical reconstruction. Orthopaedic referral. |
| MCL | Valgus stress to knee; contact or non-contact; "unhappy triad" (ACL + MCL + medial meniscus) | Valgus stress at 0° and 30° flexion; tenderness over MCL (proximal to distal); grade I–III based on laxity | Grade I–II: bracing, early ROM, physiotherapy (heals in 4–8 weeks). Grade III: orthopaedic referral; consider surgical repair if multiligament injury. |
| LCL | Varus stress; often with posterolateral corner injury; high-energy trauma | Varus stress at 0° and 30° flexion; tenderness over LCL; posterolateral drawer; dial test for posterolateral corner | Nearly always requires surgical repair/reconstruction; associated nerve injury (common peroneal) — assess dorsiflexion and sensation. Urgent orthopaedic referral. |
Multiligament knee injury: Dislocation of the knee (≥2 ligaments ruptured) is a vascular emergency. Popliteal artery injury occurs in 15–30% of knee dislocations. Perform ankle-brachial pressure index (ABPI) and urgent CT angiography if ABPI <0.9. Neurological assessment of the common peroneal nerve (dorsiflexion and sensation over the first web space) is mandatory.
ACL Reconstruction — Australian Practice Notes
ACL reconstruction is one of the most commonly performed orthopaedic procedures in Australia, with approximately 10,000 reconstructions performed annually. Hamstring tendon autograft (semitendinosus ± gracilis) and bone-patellar tendon-bone (BPTB) autograft are the two most common graft choices. Post-operative rehabilitation typically takes 9–12 months before return to pivoting sports. MBS item 49542 (knee arthroscopy with ACL reconstruction) is available under Medicare with a valid specialist referral.
Paracetamol
Panadol® · Panadol Osteo® · Analgesic (non-opioid)
Adult dose
500–1000 mg PO every 4–6 hours; max 4 g/day (reduced to 2 g/day in hepatic impairment)
Paediatric dose
15 mg/kg PO/PR every 4–6 hours; max 60 mg/kg/day
Route
Oral / Rectal / IV (propacetamol 2 g IV = paracetamol 1 g)
Renal adjustment
No dose adjustment; avoid prolonged use in severe renal impairment (eGFR <30)
PBS status
✔ PBS General Benefit
Ibuprofen
Nurofen® · Brufen® · NSAID
Adult dose
200–400 mg PO TDS–QDS with food; max 2400 mg/day; short-course recommended
Paediatric dose
5–10 mg/kg PO TDS; max 30 mg/kg/day (≤40 kg); approved ≥3 months
Route
Oral
Renal adjustment
Avoid if eGFR <30; use lowest dose for shortest duration if eGFR 30–60
Hepatic adjustment
Avoid in severe hepatic impairment (Child-Pugh C)
PBS status
✔ PBS General Benefit
Methylprednisolone acetate
Depo-Medrol® · Intra-articular corticosteroid
Adult dose
40–80 mg intra-articular injection; maximum 3 injections per joint per year; minimum 3-month interval
Route
Intra-articular (under aseptic technique)
Duration
Short-term relief (4–12 weeks); not disease-modifying
Contraindications
Septic arthritis, overlying cellulitis, prosthetic joint infection, allergy to corticosteroids
PBS status
✔ PBS General Benefit (when injected by a medical practitioner)
Flucloxacillin
Staphlex® · Floxapen® · Penicillinase-resistant penicillin
Adult dose
500 mg PO QID for 7–10 days (septic bursitis); 2 g IV every 6 hours (septic arthritis)
Paediatric dose
12.5–25 mg/kg PO QID (max 500 mg/dose); 50 mg/kg IV every 6 hours
Renal adjustment
No adjustment required for oral; reduce IV dose if eGFR <10
PBS status
✔ PBS General Benefit
Haemarthrosis & Loose Bodies
Acute Traumatic Haemarthrosis
Acute haemarthrosis is defined as rapid intra-articular blood accumulation (clinically detectable effusion) within 4 hours of injury. It is a significant clinical finding that mandates urgent evaluation. The differential diagnosis is critical because several underlying injuries require early surgical intervention.
Critical differential — Acute traumatic haemarthrosis: The most common causes are ACL rupture (70%), tibial plateau fracture (often occult — CT or MRI if X-ray normal), patellar dislocation (often with chondral/osteochondral fracture), and peripheral meniscal tear with vessel disruption. Up to 50% of tibial plateau fractures are initially missed on plain X-ray.
| Cause | Frequency | Key Distinguishing Features | Imaging |
|---|---|---|---|
| ACL rupture | ~70% | Non-contact pivot; positive Lachman; immediate swelling within 2 hours; feeling of "pop" | MRI (gold standard); X-ray may show Segond fracture (lateral tibial plateau avulsion) |
| Tibial plateau fracture | ~10–15% | Direct blow or axial loading; may be subtle on X-ray; tenderness over tibial plateau; inability to weight-bear | X-ray (AP, lateral); CT if X-ray equivocal or Schatzker classification needed |
| Patellar dislocation | ~5–10% | Often spontaneously reduced; medial patellar tenderness (MPFL tear); patellar apprehension positive; may see osteochondral loose body | X-ray (look for osteochondral fragment); MRI for MPFL assessment |
| Meniscal tear (peripheral) | ~5–10% | Twisting injury; joint line tenderness; may be combined with ACL ("unhappy triad") | MRI |
Non-Traumatic Haemarthrosis
Consider the following causes in the absence of significant trauma:
- Anticoagulant therapy: Spontaneous haemarthrosis can occur in patients on warfarin (INR >4), DOACs, or heparin — check coagulation studies and manage accordingly.
- Haemophilia / bleeding disorders: Recurrent haemarthroses, particularly in children; factor replacement required.
- Tumour (pigmented villonodular synovitis [PVNS]): Chronic haemarthrosis in a young adult; MRI shows characteristic low-signal hemosiderin deposits on T2-weighted images. Orthopaedic referral for synovectomy.
- Charcot arthropathy: Neurogenic haemarthropathy in diabetic neuropathy or peripheral neuropathy — progressive joint destruction.
Loose Bodies
Loose bodies are free-floating fragments within the joint space that may consist of cartilage, bone, or a combination. They are a common source of mechanical knee symptoms and may cause intermittent locking, catching, sudden sharp pain, and recurrent effusions.
Common Sources of Loose Bodies
- Osteochondritis dissecans: Osteochondral fragment from the medial femoral condyle (most common site)
- Osteoarthritis: Cartilaginous and osteophytic debris from articular surface degeneration
- Post-patellar dislocation: Osteochondral fracture from the medial patellar facet or lateral femoral condyle
- Synovial chondromatosis: Multiple cartilaginous nodules that detach into the joint — "snowstorm" appearance on X-ray
- Post-traumatic: Fracture fragments after intra-articular tibial plateau or distal femoral fractures
Diagnosis & Management
- X-ray: May show radio-opaque loose bodies (bone-containing); normal if purely cartilaginous
- MRI: Best for cartilaginous loose bodies and associated chondral defects
- CT arthrography: Excellent sensitivity for small loose bodies after intra-articular contrast
- Definitive treatment: Arthroscopic removal (MBS item 49584); address the underlying pathology simultaneously (chondroplasty, microfracture, OCD fixation)
- Synovial chondromatosis: Requires arthroscopic or open synovectomy with complete loose body removal
Investigations
Investigation selection should be guided by the clinical scenario, applying the Ottawa Knee Rules for fractures and reserving MRI for suspected internal derangement.
Essential
Plain X-ray Knee (AP, Lateral, Sunrise/Merchant views)
MBS item 58503. Indicated for acute trauma (Ottawa rules positive), suspected OA, loose bodies (radio-opaque), effusion. Standing weight-bearing views recommended for OA assessment. Sunrise/Merchant view for patellar pathology.
Available
MRI Knee
MBS item 63533 (MRI knee, any indication requiring specialist referral). Gold standard for meniscal tears, ligament injuries, chondral defects, OCD, bone marrow oedema, PVNS. Not first-line in OA without mechanical symptoms. Report typically available within 24–48 hours at most Australian imaging centres.
Available
Ultrasound Knee
MBS item 55804. Useful for superficial soft-tissue pathology: Baker's cyst, pes anserine bursitis, prepatellar bursitis, patellar tendinopathy, effusion assessment, guided aspiration/injection. Readily available in most Australian radiology practices.
Referral
CT Knee / CT Arthrography
MBS item 56201 (CT knee). Indicated for tibial plateau fracture characterisation (Schatzker classification), loose body detection, pre-operative planning for complex fractures. CT arthrography: intra-articular contrast + CT for chondral/loose body assessment if MRI contraindicated.
Essential
Aspirate — Synovial Fluid Analysis
MBS item 65150 (joint aspiration). Indicated for: suspected septic arthritis (Gram stain, culture, WCC >50,000/μL with >90% neutrophils), crystal arthritis (polarised microscopy for monosodium urate / calcium pyrophosphate), haemarthrosis (to confirm blood vs. reactive effusion).
Available
Blood Tests
FBC, CRP, ESR for suspected septic arthritis or inflammatory arthritis. Serum urate if crystal arthropathy suspected (though may be normal during acute gout). Rheumatoid factor, anti-CCP for suspected rheumatoid arthritis with knee involvement.
Risk Stratification & Severity Scoring
Risk stratification guides disposition, urgency of referral, and treatment intensity for patients presenting with knee pain.
Low Risk
Non-acute Presentation
Insidious onset, no red flags, can weight-bear, no effusion or mild effusion, normal neurovascular status, no mechanical symptoms.
Setting: GP management — conservative, physiotherapy, 6-week review
Moderate Risk
Acute Injury — No Red Flags
Acute onset but can weight-bear, moderate effusion, no locking, positive special tests (McMurray, Lachman), Ottawa rules negative.
Setting: X-ray, consider MRI, sports medicine/orthopaedic referral within 2–4 weeks
High Risk
Acute Injury — Red Flags Present
Acute haemarthrosis, locked knee, inability to weight-bear, gross deformity, neurovascular compromise, suspected fracture, suspected septic arthritis, open injury.
Setting: ED assessment, urgent orthopaedic referral, same-day imaging
Management
General Principles — Acute Knee Injury
The POLICE protocol (Protection, Optimal Loading, Ice, Compression, Elevation) has replaced the older RICE approach in Australian sports medicine practice. The focus is on early protected mobilisation rather than prolonged rest.
P
Protection
Hinged knee brace or crutches to protect the injured structure while maintaining some functional movement. Avoid complete immobilisation unless fracture or post-surgical.
OL
Optimal Loading
Early gentle range-of-motion exercises and weight-bearing as tolerated promotes tissue healing and prevents deconditioning. Modify loading based on injury type and pain.
I
Ice
Apply for 15–20 minutes every 2–3 hours in the first 48–72 hours. Reduce pain and swelling. Use ice wrapped in a damp towel to prevent cold injury.
C
Compression
Elastic bandage or compression sleeve to limit swelling. Ensure not too tight — check distal pulses and sensation.
E
Elevation
Elevate the affected limb above the level of the heart when resting to facilitate venous return and reduce swelling.
Pharmacological Management
Analgesic ladder for acute knee pain: Step 1 — Paracetamol (1 g QDS) ± topical NSAIDs (diclofenac gel 1% TDS). Step 2 — Add oral NSAIDs (ibuprofen 400 mg TDS or naproxen 500 mg BD) for 5–7 days. Step 3 — Consider short-course opioids (oxycodone 5 mg PRN) only for severe acute pain (<3 days); avoid in chronic knee pain. Intra-articular corticosteroid injection for OA flare (maximum 3 per year).
Directed / Definitive Therapy
| Condition | Conservative | Surgical |
|---|---|---|
| PFPS | Physiotherapy (VMO strengthening, hip abductor programme), patellar taping, activity modification. Expected improvement 6–12 weeks. | Rarely required. Lateral retinacular release for refractory cases with lateral patellar tilt. |
| Degenerative meniscal tear | Physiotherapy, NSAIDs, activity modification. Evidence shows no benefit of arthroscopic surgery over physiotherapy for degenerative tears in OA (ESCAPE trial, NEJM 2018). | Arthroscopic partial meniscectomy only for persistent mechanical symptoms >3 months despite rehabilitation. |
| Traumatic meniscal tear | Physiotherapy for stable, peripheral red-zone tears in young patients. | Arthroscopic meniscal repair (preferred for peripheral red-zone tears in younger patients) vs. partial meniscectomy. MBS item 49584. |
| ACL rupture | Neuromuscular rehabilitation, bracing. Suitable for low-demand patients or those willing to modify activity. Risk of secondary meniscal/chondral injury with pivoting activities. | Arthroscopic reconstruction (hamstring or BPTB autograft). Recommended for young active patients, competitive athletes, and those with combined ligament injuries. Return to sport: 9–12 months. MBS item 49542. |
| Patellar dislocation | Closed reduction (if still dislocated — extend knee, gently slide patella laterally). Physiotherapy (VMO strengthening, medial stabilisation). Bracing for 4–6 weeks. Recurrence rate ~30%. | MPFL reconstruction for recurrent dislocations (≥2 events) or osteochondral fracture requiring fixation. |
| Loose bodies | Not amenable to conservative management. | Arthroscopic removal (MBS item 49584). Address underlying pathology (OCD fixation, chondroplasty, synovectomy for PVNS). |
Monitoring & Follow-Up
- Acute injury: Review at 1–2 weeks to assess progress, ensure adequate pain control, and arrange imaging or referral as needed.
- Conservative management: 6-week review to assess response to physiotherapy; MRI referral if inadequate improvement.
- Post-surgical: 2-week wound review, 6-week progress assessment, 3-month milestone check, 9–12-month return-to-sport testing (ACL reconstruction).
- OA management: 3-monthly reviews initially; then 6–12-monthly once stable. Monitor for surgical referral criteria (persistent symptoms ≥6 months, functional limitation, X-ray grade ≥2 [Kellgren-Lawrence]).
- Septic arthritis: Serial CRP and inflammatory markers every 48–72 hours; clinical improvement expected by day 3–5 of IV antibiotics. If poor response, consider repeat aspiration or surgical washout.
Special Populations
Paediatrics
Osgood-Schlatter disease: Self-limiting tibial tuberosity apophysitis. Age 10–15 years. Activity modification, ice, NSAIDs. Resolves with skeletal maturity. No X-ray usually required.
Osteochondritis dissecans: Peak 12–19 years. MRI for stability assessment. Stable lesions: rest + physiotherapy. Unstable: arthroscopic fixation.
Discoid lateral meniscus: Congenital variant; presents in childhood/adolescence with lateral knee pain, snapping, and swelling. MRI diagnosis. Arthroscopic saucerisation if symptomatic.
Paediatric ACL injuries: Increasing incidence. Reconstruction techniques modified to protect growth plates (physeal-sparing). Specialist paediatric orthopaedic referral required.
Intra-articular corticosteroids: Contraindicated in children. May cause cartilage damage and growth disturbance.
Consider referred hip pain (SUFE / Perthes disease) in any child presenting with knee pain — always examine the hip.
Pregnancy
Physiological laxity: Relaxin-mediated ligament laxity increases risk of knee instability. Manage with physiotherapy and supportive bracing.
Paracetamol: Paracetamol is considered safe in all trimesters. First-line analgesia.
NSAIDs: Avoid in third trimester (risk of premature closure of ductus arteriosus, oligohydramnios). Short-course ibuprofen acceptable in first and second trimesters if clinically necessary.
MRI: No ionising radiation; safe in pregnancy. Avoid gadolinium contrast unless absolutely essential.
X-ray of the knee with abdominal shielding may be performed if clinically essential. Low radiation dose to the foetus.
Elderly (≥65 years)
Osteoarthritis: Most common cause of knee pain in this age group. Multimodal management: exercise, weight loss, paracetamol, topical NSAIDs, intra-articular corticosteroids.
Insufficiency fractures: Spontaneous fractures (e.g., insufficiency fracture of the lateral tibial plateau) in osteoporotic bone. May occur with minimal trauma. MRI is more sensitive than X-ray.
NSAIDs: Use with caution — increased risk of GI bleeding, renal impairment, cardiovascular events. Topical NSAIDs preferred. Consider PPI cover (pantoprazole 40 mg daily) if oral NSAID required.
Falls risk: Knee pain contributes to falls in the elderly. Physiotherapy for balance and strength training is essential. Hip protectors if recurrent falls.
Total knee replacement is highly effective for end-stage OA. Pre-operative optimisation includes weight management, diabetes control, and smoking cessation. Average hospital stay: 3–5 days.
Renal Impairment
NSAIDs: Avoid if eGFR <30. Use with extreme caution (lowest dose, shortest duration) if eGFR 30–60. Risk of AKI, fluid retention, hyperkalaemia.
Pseudogout (CPPD): More common in chronic kidney disease. Acute CPPD arthritis of the knee — treat with aspiration + intra-articular corticosteroid or short-course colchicine (0.5 mg BD, adjusted for renal function).
Dialysis-related amyloidosis: Chronic β2-microglobulin amyloid deposits in the knee after >10 years of haemodialysis. Presents with carpal tunnel syndrome, periarticular soft-tissue masses, and knee pain.
Paracetamol is safe in renal impairment (reduce max dose to 2 g/day if eGFR <30 for prolonged use).
Hepatic Impairment
Paracetamol: Reduce maximum dose to 2 g/day in chronic liver disease. Safe at standard doses in mild impairment (Child-Pugh A).
NSAIDs: Avoid in Child-Pugh B and C — increased bleeding risk (coagulopathy, portal hypertension), renal impairment, fluid retention.
Haemarthrosis risk: Coagulopathy associated with advanced liver disease predisposes to spontaneous haemarthrosis. Correct INR with vitamin K or fresh frozen plasma if aspiration required.
Corticosteroid injections are safe in hepatic impairment — no dose adjustment required.
Immunocompromised
Septic arthritis risk: Heightened suspicion required in patients on immunosuppressants (DMARDs, biologics, corticosteroids, transplant recipients). Lower threshold for joint aspiration and empirical antibiotics.
Atypical organisms: Consider fungal, mycobacterial, and opportunistic infections in severely immunocompromised patients (e.g., Mycobacterium tuberculosis, Candida species). Extended culture incubation and synovial biopsy may be required.
Crystal arthropathy: Immunosuppression and transplant medications (cyclosporine) increase gout risk. Avoid allopurinol during acute flare — use colchicine (0.5 mg BD) or intra-articular corticosteroid.
DMARDs and biologics should be withheld peri-operatively for orthopaedic procedures. Coordinate with the treating rheumatologist for peri-operative medication management.
Aboriginal and Torres Strait Islander Health Considerations
Aboriginal and Torres Strait Islander Health
Aboriginal and Torres Strait Islander Australians experience a significantly higher burden of musculoskeletal disease compared with the non-Indigenous population. Osteoarthritis of the knee is approximately 1.7 times more prevalent, and rates of knee replacement surgery remain lower despite higher need — reflecting persistent barriers to access. Culturally safe, responsive care is essential.
Practical strategies: Telehealth orthopaedic consultations (MBS item 99200) can bridge the access gap for remote communities. The Royal Flying Doctor Service (RFDS) and visiting specialist programmes provide orthopaedic outreach clinics in many remote areas. Referral to Aboriginal Community Controlled Health Organisations (ACCHOs) for ongoing chronic disease management of OA is strongly encouraged.
📚 References
- 1. Australian Institute of Health and Welfare (AIHW). Musculoskeletal conditions in Australia. Cat. no. PHE 254. Canberra: AIHW; 2023.
- 2. Royal Australian College of General Practitioners (RACGP). Guidelines for preventive activities in general practice (Red Book). 9th edn. Melbourne: RACGP; 2018.
- 3. Stiell IG, Greenberg GH, Wells GA, et al. Prospective validation of a decision rule for the use of radiography in acute knee injuries. JAMA. 1996;275(8):611–615. (Ottawa Knee Rules)
- 4. Brignardello-Petersen R, Guyatt GH, Buchbinder R, et al. Knee arthroscopy versus conservative management in patients with degenerative knee disease: a systematic review. BMJ Open. 2017;7(5):e016114. (ESCAPE trial reference)
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