Physiotherapy assessment for knee pain
1. Subjective history
Ask about:
- Location: anterior, medial, lateral, posterior, or diffuse pain
- Onset: sudden after trauma or gradual
- Mechanism: twist/pivot, fall, direct blow, hyperextension, overuse, increase in running or stairs
- Symptoms: swelling, locking, catching, clicking, giving way, instability, stiffness, numbness, fever
- Pain behavior: severity, 24-hour pattern, night pain, aggravating and easing activities
- Functional limitations: walking, stairs, squatting, kneeling, sit-to-stand, running, sport, work, sleep
- Past history: prior injury/surgery, osteoarthritis, inflammatory arthritis, gout, infection, medication, imaging
- Goals: return to walking, work, stair climbing, sport, etc.
Helpful symptom patterns
- A twist with joint-line pain, swelling, catching or inability to fully straighten may suggest a meniscal injury.
- A “pop,” rapid swelling, and instability after pivoting may occur with cruciate-ligament injury.
- Anterior pain aggravated by stairs, squats, running, or prolonged sitting is common in patellofemoral presentations.
- Gradual activity-related pain, morning stiffness less than 30 minutes, crepitus, and reduced walking tolerance can fit knee osteoarthritis.
2. Screen for red flags
Arrange urgent medical assessment for:
- A hot, red, markedly swollen knee, fever, or feeling unwell: possible joint infection.
- Major trauma, visible deformity, open wound, inability to bear weight, or suspected fracture/dislocation.
- A cold, pale foot, weak/absent pulses, altered sensation, or severe calf swelling.
- Rapidly worsening pain or swelling, unexplained night pain, weight loss, or history of cancer.
- True locking, where the knee physically cannot fully extend.
- Progressive neurological weakness or symptoms suggesting referred pain from the hip or lumbar spine.
NICE advises considering infection, tumour, inflammatory polyarthritis, and significant bone or soft-tissue injury during knee-pain screening.
NICE knee-pain guidance
3. Observation
Compare both lower limbs during standing and walking:
- Gait: antalgic gait, reduced stance time, varus thrust
- Alignment: genu varum/valgum, flexion posture, hyperextension
- Swelling: generalized effusion, localized prepatellar swelling, popliteal swelling
- Skin: erythema, bruising, wounds, scars
- Muscle bulk: quadriceps or calf wasting
- Foot posture and footwear
- Use of braces, crutches, or walking aids
Assessment should inspect the knee from all sides and include quadriceps wasting, swelling, deformity, and alignment. Bailey and Love's Short Practice of Surgery, p. 512.
4. Palpation
Check and compare:
- Temperature and tenderness
- Effusion: patellar tap or sweep/bulge test
- Joint line: meniscal or osteoarthritic tenderness
- Patella and retinaculum
- Patellar tendon, quadriceps tendon, tibial tuberosity
- Medial and lateral collateral ligaments
- Pes anserine area, iliotibial-band region, fibular head
- Popliteal fossa and calf
Also palpate and assess the hip, tibia/fibula, and lumbar spine when appropriate because pain can be referred to the knee. Rosen’s Emergency Medicine, p. 712.
5. Movement assessment
Assess active and passive movement, comparing sides:
- Knee flexion and extension
- Pain, stiffness, end-feel, crepitus
- Extension lag or inability to perform a straight-leg raise
- Hip range of movement, especially internal rotation
- Ankle range where gait mechanics may contribute
6. Strength and functional assessment
Assess:
- Quadriceps strength and activation
- Hip abductors, extensors, and external rotators
- Hamstrings and calf strength
- Single-leg stance and balance
- Sit-to-stand
- Step-up/step-down
- Squat or single-leg squat, if safe
- Walking tolerance, stairs, running or hopping for sport-specific cases
Record a baseline outcome measure, such as:
- Numeric Pain Rating Scale
- Patient-Specific Functional Scale
- Knee injury and Osteoarthritis Outcome Score, or KOOS
- Timed Up and Go or 30-second Sit-to-Stand, where relevant
7. Special tests
Use only after the history and basic examination suggest a relevant problem.
| Suspected problem | Common tests |
|---|
| ACL injury | Lachman, anterior drawer, pivot shift |
| PCL injury | Posterior drawer, posterior sag |
| MCL/LCL injury | Valgus and varus stress tests |
| Meniscal injury | Joint-line tenderness, Thessaly or McMurray |
| Patellofemoral disorder/instability | Patellar apprehension, patellar mobility, functional squat/step-down |
| Extensor mechanism injury | Straight-leg raise, active knee extension |
Document that test findings are part of a cluster, not a stand-alone diagnosis.
8. Assessment summary and plan
Finish with:
- Physiotherapy problem list, for example pain, reduced flexion, quadriceps inhibition, poor stair tolerance.
- Likely contributing factors, such as acute trauma, loading error, hip weakness, reduced balance, obesity, or fear of movement.
- Goals, for example walk 30 minutes, climb stairs independently, return to sport.
- Initial management, often education about activity modification, progressive strengthening, range-of-motion work, and balance or gait training.
- Reassessment plan, using the same pain, function, and movement measures.
A focused knee examination includes neurovascular status, effusion/deformity/open wounds, infection signs, tenderness localization, range of motion, stability, and extensor-mechanism integrity. Rosen’s Emergency Medicine, p. 712.