Lachman test
With the knee slightly bent, the examiner assesses forward translation of the shin bone relative to the thigh bone to evaluate the anterior cruciate ligament.
Darker cells mean a higher score for this topic on that metric.
Pain frequency65
Recovery length55
Exercise load60
Clinician need60
Self-care fit50
Recurrence risk60
LessMore
Last reviewed Sources & creditsMedia creditsMethodology
Quick answers
What is patellofemoral pain syndrome?
Patellofemoral pain syndrome describes pain around or behind the kneecap, often related to how the kneecap tracks in its groove during bending movements, and is common among runners and young active individuals.
What is the difference between the meniscus and the ACL?
The menisci are C-shaped cartilage cushions that absorb shock between the thigh and shin bones, while the anterior cruciate ligament (ACL) is one of several ligaments that control the knee's stability during rotation and forward sliding of the shin bone.
Does every meniscus tear need surgery?
Many meniscus tears, particularly smaller or degenerative tears in middle-aged and older adults, are managed successfully with exercise-based rehabilitation, while larger or mechanically unstable tears may be considered for surgical repair.
Is running bad for the knees?
Current evidence generally does not support the idea that recreational running increases the risk of knee osteoarthritis, and moderate running is often considered compatible with long-term joint health for most people.
What does a 'locked knee' mean?
A locked knee refers to an inability to fully bend or straighten the joint, often due to a displaced piece of torn meniscus or loose cartilage fragment, and typically warrants prompt evaluation.
How common is knee osteoarthritis?
Knee osteoarthritis is among the most common joint conditions affecting older adults, with prevalence increasing steadily with age and additional risk associated with prior injury and higher body weight.
Knee assessment typically begins with a history of onset, mechanism of injury if applicable, and pain location, followed by observation of swelling, alignment, and active range of motion.
A battery of special tests then helps assess ligament stability, meniscus integrity, and patellofemoral mechanics, guiding whether further imaging or referral is warranted.
Assessment tests
McMurray test
Combining knee rotation with bending and straightening while palpating the joint line can reproduce clicking or pain associated with a meniscus tear.
Patellar grind (compression) test
Gently compressing the kneecap against the thigh bone during a slight contraction can reproduce pain typical of patellofemoral pain syndrome.
Valgus and varus stress tests
Applying gentle sideways stress to the knee at slight bending evaluates the integrity of the inner and outer collateral ligaments.
Functional single-leg squat
Observing alignment and control during a single-leg squat helps identify movement patterns, such as excessive inward knee collapse, relevant to several overuse conditions.
Warning signs
These warrant prompt clinical review rather than unsupervised exercise progression.
Inability to bear weight after injury
A sudden inability to bear weight following a twisting or impact injury raises concern for fracture or significant ligament injury and warrants urgent evaluation.
Locked knee
An inability to fully bend or straighten the knee, often due to a displaced meniscus fragment or loose body, typically requires prompt evaluation.
Significant, rapid swelling after injury
Marked swelling developing within hours of an injury can indicate a significant internal injury such as a ligament tear and warrants assessment.
Signs of infection
Warmth, redness, and fever around the knee raise concern for septic arthritis, a medical emergency requiring urgent care.
This combination of history, special tests, and functional assessment allows clinicians to distinguish between the knee's many possible sources of pain and determine whether imaging or specialist referral is warranted.
Keep exploring
Neighbouring regions
Neighbouring topics share region literacy — not a severity ranking.
Hip
The hip is a deep, stable ball-and-socket joint that bears several times body weight during walking and running, making it a common site of both overuse pain and degenerative change.
Pain frequency 55 Same body regionACL
The anterior cruciate ligament stabilizes the knee against pivoting and forward-sliding forces, and its rupture is one of the most studied and rehabilitation-intensive sports injuries.
Pain frequency 50 Same body regionAnkle & Foot
The ankle and foot absorb and redirect the full force of body weight with every step, making sprains and overuse injuries among the most common in sport and daily life.
Pain frequency 70 Same body region