A physical therapist uses the Ottawa Knee Rules to assess a patient with acute knee trauma. Which of the following findings would indicate a possible knee fracture and justify the need for radiographic imaging? 

1. A 15 degree loss of passive knee extension
2. Isolated tenderness of the patella
3. Tenderness along the medial and lateral joint lines
4. Active knee flexion limited to 105 degrees

Transcript

Welcome back to the Scorebuilders’ Question and Answer Podcast! This podcast provides members of the Scorebuilders’ team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination. My name is Scott Giles and I will be your host for today’s journey.

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A physical therapist uses the Ottawa Knee Rules to assess a patient with acute knee trauma. Which of the following findings would indicate a possible knee fracture and justify the need for radiographic imaging? 

1. A 15 degree loss of passive knee extension
2. Isolated tenderness of the patella
3. Tenderness along the medial and lateral joint lines
4. Active knee flexion limited to 105 degrees

Ottawa Knee Rules
The Ottawa Knee Rules is an instrument used for patients with acute trauma to the knee in which a fracture may be suspected. If the patient meets any of the five criteria within the instrument, they should be referred for radiographs. Let’s explore the five predictive factors.

Predictive Factors 
1.    Age is > 54 years old 
2.    Tenderness at the fibular head 
3.    Isolated tenderness of the patella without other bone tenderness 
4.    Inability to flex the knee 90 degrees 
5.    Inability to bear weight for four steps (both immediately and in the emergency department) 

This is a question where a student may be able to use deductive reasoning to determine which finding is most likely associated with a possible knee fracture. However, to definitively answer the question, it’s necessary to have detailed knowledge of the predictive factors associated with the Ottawa Knee Rules.

Let’s explore each of the options:

Option 1 – A 15 degree loss of passive knee extension
A 15 degree loss of passive knee extension could be associated with a variety of orthopedic knee injuries. While knee extension range of motion may be limited with a knee fracture, it’s not a criterion within the Ottawa Knee Rules and is therefore not sufficient to justify imaging for a possible fracture.

If the patient was unable to flex the knee to 90 degrees, this option would be more compelling. A 15 degree loss of passive knee extension indicates that the knee can still be flexed to approximately 120 degrees.

Option 2 – Isolated tenderness of the patella
Isolated tenderness of the patella is one of five key criteria in the Ottawa Knee Rules that suggest the need for a radiograph.

If a patient has tenderness only over the patella with no other bony tenderness, it may indicate a patellar fracture, particularly following a fall or direct blow to the knee. This finding is especially significant because soft tissue injuries typically do not produce focal tenderness strictly limited to the patella.

Option 3 – Tenderness along the medial and lateral joint lines
Tenderness along the medial and lateral joint lines is commonly associated with meniscal injuries or arthritis, not fractures. 

This finding is often associated with intra-articular pathology, but it is not a criterion within the Ottawa Knee Rules.

Option 4 – Active knee flexion limited to 105 degrees
An inability to flex the knee is one of the criterion that is considered with the Ottawa Knee Rules. However, the patient should be referred for a radiograph if they are unable to flex the knee to 90 degrees.

The information in the question stem indicates the patient can actively flex the knee to 105 degrees

The correct answer is Option 2.

Let’s explore the all student data:
25% of students selected Option 1 – A 15 degree loss of passive knee extension
50% of students selected Option 2 - Isolated tenderness of the patella - the correct response
10% of students selected Option 3 - Tenderness along the medial and lateral joint lines
15% of students selected Option 4 - Active knee flexion limited to 105 degrees

System Classification
This question is a Musculoskeletal Systems question which represents approximately 27% of all exam items.

Content Outline Classification
This question is a Physical Therapy Examination question which represents approximately 24% of all exam items.

Level Classification
This question is a Level 1 question since the question requires students to possess basic foundational academic knowledge. Remediation of Level 1 questions occurs through academic review of entry-level content using textbooks, review books, Basecamp, and flash cards.

Academic Focus Area
Looking to review related academic content? Check out page 114 in PTEXAM: The Complete Study Guide.

Thanks for joining us on the Scorebuilders Q and A podcast! See you next week!