Differentials
Biceps femoris tendinopathy
SIGNS / SYMPTOMS
Pain over the biceps femoris.
Pain with resisted knee flexion.
INVESTIGATIONS
Clinical differentiation usually suffices.
Degenerative joint disease
SIGNS / SYMPTOMS
Joint line pain or diffusion.
INVESTIGATIONS
X-ray shows new bone formation (osteophytes), joint space narrowing, and subchondral sclerosis and cysts.
Lateral collateral ligament (LCL) sprain
SIGNS / SYMPTOMS
Pain over the LCL.
Pain provocation with various stress tests.
Varus instability test to check the LCL. With the patient lying flat and the knee held at about 30° of flexion, the shin is shifted to the medial side. Insufficiency of the LCL will allow the knee to 'open up' excessively. The test is repeated with the leg straight. If the knee still opens up excessively, then more than just the LCL is torn.
INVESTIGATIONS
Clinical differentiation usually suffices.
Lateral meniscal tear
SIGNS / SYMPTOMS
Joint line tenderness.
Positive McMurray's test. The McMurray's test is performed with the patient lying flat (non-weight bearing) and the examiner bending the knee. A click is felt over the meniscus tear as the knee is brought from full flexion to 90° of flexion.
INVESTIGATIONS
MRI shows signal changes within meniscus on T1 and T2 images; sagittal views: anterior and posterior meniscal tears; coronal view: far medial and far lateral meniscal tears.
Myofascial pain
SIGNS / SYMPTOMS
Pain in the muscle belly.
Referred pain with palpation of trigger point.
INVESTIGATIONS
Clinical differentiation usually suffices.
Patellofemoral stress syndrome
SIGNS / SYMPTOMS
Anterior knee pain.
Tenderness in the lateral patellar set.
Positive patellar compression test. The test is performed by compressing the patella down into the trochlear groove as the patient flexes and extends the knee.
INVESTIGATIONS
Clinical differentiation usually suffices.
Popliteal tendinopathy
SIGNS / SYMPTOMS
Tenderness of the popliteal tendon.
Positive figure of 4 test.
Positive Garrik's test. The test is performed with the patient supine; the knee is flexed to 90°, the leg internally rotated, and the patient is asked to resist the examiner's attempt to externally rotate the tibia.
INVESTIGATIONS
Clinical differentiation usually suffices.
Referred pain from lumbar spine
SIGNS / SYMPTOMS
Pain provocation with straight legs raised or slump test.
INVESTIGATIONS
X-ray: plain radiographs should be obtained if pain is not settling after 6 to 8 weeks.
MRI or CT: considered if neurological compromise, infection, or tumour is suggested by clinical evaluation.
Stress fracture
SIGNS / SYMPTOMS
Pain with palpation over bone.
INVESTIGATIONS
MRI: demonstrates fracture.
Bone scan: evidence of uptake correlating with the area of pain.
Superior tibiofibular joint sprain
SIGNS / SYMPTOMS
Tenderness of the tibiofibular joint.
Instability testing of the tibiofibular joint.
INVESTIGATIONS
Clinical differentiation usually suffices.
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