Knee Assessment
- Paul Williamson

- Jun 29, 2023
- 2 min read
Updated: Jan 31
Special Tests for the Knee

Musculoskeletal knee pain is a significant problem and ‘Special clinical tests’ are often used to provide the diagnosis. A plethora of publications within the literature have investigated the diagnostic accuracy of these assessments, yet despite the wealth of research their diagnostic accuracy remains unclear.
Assessments
Effusion
Grade effusion using a visual 'bulge' sign
Grade effusion using a visual return of fluid following a sweep
Evidence suggests individual assessments have low validity
Diagnostic accuracy can be improved with experience
Combining tests can improve sensitivity
Anterior Cruciate Ligament - ACL Injury
Anterior Draw Test
Positive = Greater anterior Tibial translation compared to contralateral side
Lachman's Test
Positive = Greater anterior Tibial translation compared to contralateral side
Pivot Shift Test
Positive = Audible 'thud' or 'click'
This combination of ACL tests provides highly accurate system of ruling in and out ACL injury particularly in non-acute patients.
Posterior Cruciate Ligament - PCL Injury
Posterior Draw test
Positive = posterior motion / translation of Tibia
Grade 1= 0-5mm
Grade 2 = 6-10mm
Grade 3 = 11mm +
Posterior Sag sign
Positive = Posterior sagging of the Tibia secondary to gravitational pull
This combination of PCL tests provides high levels of specificity and sensitivity to rule in and out a PCL injury
Meniscal Injury
Joint Line Tenderness
Positive with reproduction of patients pain
End Range Flexion
Positive for pain or block preventing full flexion
McMurry's Test
Positive with pain &/or Audible 'Clunk / Click'
Full Squat (if able)
Positive for pain or block preventing full flexion
Duck Waddle (if able)
Positive for pain or block preventing full flexion
The diagnostic accuracy of meniscal testing is somewhat variable.
Combining patient history, physical findings and special tests seem to be the most sensible approach to diagnosis.
Medial Collateral Ligament - MCL Injury
Valgus Stress test
Positive when excessive medial joint line gapping is noted at approximately 30 degrees knee flexion
This assessment appears sensitive for ruling out an MCL injury when the test is negative
Lateral Collateral Ligament - LCL Injury
Varus Stress Test
Positive when excessive lateral joint line gapping is noted at approximately 30 degrees knee flexion
There is limited research available which evaluates the reliability of LCL assessment diagnostic accuracy
Patella Femoral Instability (Dislocation / Subluxation Risk)
Patella Apprehension Test
Positive when patient shows signs of apprehension / pain during lateral patella glide
A specific test which helps to rule in patellofemoral instability
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