Patellar Grind Test

 Patellar Grind Test

What is Patellar Grind Test?

Patellar Grind Test (Zohlen Sign or Clarke sign) is used to evaluate patellofemoral Pain Syndrome (chondromalacia patellae).

How is Patellar Grind Test performed?

Patellar Grind Test

What does a positive Patellar Grind Test mean?

Sensitivity & Specificity 

A Validation study by Scott T Doberstein1 to evaluate the diagnostic value of the clarke sign in assessing Chondromalacia Patella, he found the sensitivity & specificity was:


As this test is often positive in normal patients, one should repeat the procedure several times, increasing the pressure on the patella each time and comparing the results with those of the unaffected side.

To better localize the retropatellar damage, the knee should be tested in 30°, 60°, and 90° of flexion as well as in full extension.

Chondromalacia patella

The term chondromalacia patella has long been a catch-all category of anterior and, specifically, retropatellar knee pain.

The term chondromalacia was first used by Aleman in 1928. He used the term “chondromalacia posttraumatica patellae” to describe lesions of the patella found at surgery and thought to be caused by prior trauma.

With time, chondromalacia became an all-inclusive term with no agreed-on classification system or definitions of terms.

True chondromalacia refers to a softening of the cartilage on the posterior aspect of the patella and is estimated to occur in fewer than 20% of persons who present with anterior knee pain.

The syndrome is most common in the 12–35-year-old age group, and most studies show a predominance in

Chondromalacia patella
Chondromalacia patella

Two types of chondromalacia have been described:

  1. One type involves surface degeneration of the patella that is age dependent and most often asymptomatic.
  2. The other type involves basal degeneration. This type results from trauma and abnormal tracking of the patella and is symptomatic.

Chondromalacia patella Classification:

Chondromalacia is classified into four grades, according to the degree of degeneration noted arthroscopically:

Chondromalacia patella grading
Chondromalacia patella Classification


  1. Doberstein ST, Romeyn RL, Reineke DM. The diagnostic value of the Clarke sign in assessing chondromalacia patella. J Athl Train. 2008 Apr-Jun;43(2):190-6. doi: 10.4085/1062-6050-43.2.190. PMID: 18345345; PMCID: PMC2267328.
  2. Aleman O: Chondromalacia post-traumatica patellae. Acta Chir Scand 63:149–190, 1928
  3. Holmes SWJ, Clancy WGJ: Clinical classification of patellofemoral pain and dysfunction. J Orthop Sports Phys Ther 28:299–306, 1998.
  4. OUTERBRIDGE RE. The etiology of chondromalacia patellae. J Bone Joint Surg Br. 1961 Nov;43-B:752-7. doi: 10.1302/0301-620X.43B4.752. PMID: 14038135.
  5. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.

Share with Friends:

Read Also:

Related Tests

Dial Test

Dial Test (or tibial external rotation test) is used in evaluation of posterolateral instability of the knee. It…

Thessaly Test

Thessaly test is used to detect lateral or medial meniscal tears / lesions of the knee joint. It is based…

Lachman Test

Lachman Test (or Noulis Test) is used to assess the integrity of the anterior cruciate ligament (ACL) of…

See Also:

Latest from Orthofixar

Distal Radius Fractures

Distal Radius Fractures is the most common fracture encountered by orthopedic trauma surgeons accounting for 17.5% of all…

Kohler’s Disease

Kohler's Disease (or Osteochondrosis of the tarsal navicular) is an avascular necrosis of the navicular bone of the…

Dupuytren Contracture

Dupuytren contracture is a painless, but progressive flexion contracture of the fingers caused by a benign fibroproliferative disorder.

Mortons Neuroma Symptoms and Treatment

Mortons Neuroma is a compressive neuropathy of the interdigital nerve, usually between the third and fourth metatarsals.

Special Tests App

Special Test Application
Special Test Application