**[Differential Diagnosis -- Knee Pain]{.underline}**

**Submitted by:**

**LT Matthew Armentano**

**matthew.armentano@ihs.gov**

**[Differential Diagnosis of Knee Pain by Age Group]{.underline}**

  ----------------------- ----------------------- -----------------------
  **Children and                                  **Older adults**
  adolescents**                                   

  Patellar subluxation    Patellofemoral pain     Osteoarthritis
                          syndrome                
                          (chondromalacia         
                          patellae)               

  Tibial apophysitis      Medial plica syndrome   Crystal-induced
  (Osgood-Schlatter                               inflammatory
  lesion)                                         arthropathy: gout,
                                                  pseudogout

  Jumper's knee (patellar Pes anserine bursitis   Popliteal cyst (Baker's
  tendonitis)                                     cyst)

  Referred pain: slipped  Trauma: ligamentous     Metastatic Cancer
  capital femoral         sprains (anterior       
  epiphysis, hip fracture cruciate, medial        
                          collateral, lateral     
                          collateral), meniscal   
                          tear, Fractures, muscle 
                          strains                 

  Osteochondritis         Inflammatory            
  dissecans               arthropathy: rheumatoid 
                          arthritis, Reiter's     
                          syndrome, Pigmented     
                          Villanodular Synovitis  

  Juvenile Rheumatoid     Tendonitis (quadriceps, 
  Arthritis               Patellar tendon, etc)   

  Trauma: ligamentous     Septic arthritis        
  sprains (anterior                               
  cruciate, medial                                
  collateral, lateral                             
  collateral), meniscal                           
  tear, Fractures to                              
  include Epiphyseal                              
  Fracture , muscle                               
  strains                                         

                          Stress Fracture/Stress  
                          Reaction                

                          Referred Pain:          
                          Neurogenic, Hip and leg 
                          pathology               
  ----------------------- ----------------------- -----------------------

# Common Knee pain by Anatomic Site

**Anterior knee pain**

> Patellar subluxation or dislocation
>
> Tibial apophysitis (Osgood-Schlatter lesion)
>
> Jumper\'s knee (patellar tendonitis)
>
> Patellofemoral pain syndrome (chondromalacia patellae)

**(Common knee pain by anatomical site, continued)**

**Medial knee pain**

> Medial collateral ligament sprain
>
> Medial meniscal tear
>
> Pes anserine bursitis
>
> Medial plica syndrome

**Lateral knee pain**

> Lateral collateral ligament sprain
>
> Lateral meniscal tear
>
> Iliotibial band tendonitis

**Posterior knee pain**

> Popliteal cyst (Baker\'s cyst)
>
> Posterior cruciate ligament injury

**[Mechanism of Injury:]{.underline}**

**Trauma -** Fracture of Femur, Tibia, Fibula, Patella

-   Ligamentous Sprain (ACL, MCL, LCL, PCL)

-   Mensical Tear

-   Patellar subluxation/dislocation

-   Muscle Strain

-   Osteochodral fracture

**Atraumatic -** Osteoarthrits

-   Rheumatoid or other inflammatory Arthritis (Pigmented villonodular
    arthritis, gout, reiters syndrome)

-   Septic Arthrits

-   Popliteal cyst

-   Stress Fractures/reactions (tibial plateau & shaft, femur, patella)

-   Tendonitis

-   Patellofemoral Syndrome

-   Medial plica syndrome

-   Referred pain (hip OA, Lumbar radicular sx)

-   Metastatic cancer

**[References:]{.underline}**

**Diagnosis and management of the osteonecrotic triad of the knee**. PM
Soucacos, et al. *Ortho Cl N Am*, 35 (2004) 371-381*.*

### Evaluation of Patients Presenting with Knee Pain: Part II. Differential Diagnosis. WL Calmbach and M. Hutchens, *American Family Physician*, Volume 68 • Number 5 • September 1, 2003 

### www.wheelessonline.com

### 

Knee- Special Tests

Submitted by:

LT David Honaberger

david.honaberger@fdih.ihs.gov

According to below references 2,3 and 6, clinical examination by an
orthopedist including subjective interview and radiographs, Lachman's,
Pivot-shift, Anterior Drawer, Apley's was just as good (specific,
sensitive, accurate) or better than MRI. The majority were verified
through arthroscopy.

Pookarnjanamorakot C Et al, reference 4, reported on accuracy of
clinical meniscal tests:

[Sensitivity (%)]{.underline} [Specificity (%)]{.underline} [Accuracy
(%)]{.underline}

McMurray's 28 92 44

Apley's 16 100 37

Steinmann I 29.3 100 47

Childress' sign 68 60 66

Jt. Line tenderness 26.7 96 44

Hammer WI, reference 1, described meniscal motion: *"As the knee flexes,
the menisci move posterior partly due to the contraction of the
semimembranosus and popliteus which attach to the posterior medial and
lateral menisci respectively. Contraction of the quadriceps by its
effect on the patellofemoral mechanism pulls both menisci forward with
knee extension."*

Due to the variance in the above numbers by different researchers
perhaps the meta analysis by Scholten Et al, reference 5, perhaps is
more reflective of true clinical knee ACL test values:

[Pooled Sensitivity]{.underline} [Pooled Specificity]{.underline}
[Sensitivity]{.underline} [Specificity]{.underline}

Anterior Drawer 0.62 (95%) 0.88 (95%)

Pivot Shift \-- \-- 0.18-0.48 0.97-0.99

Lachman's 0.86 (95%) 0.91 (95%)

\* I highly recommend a brief review of all the below literature, it was
worthwhile.

REFERENCES:

1.  Hammer WI. Diagnosing a meniscus tear. *Dynamic Chiropractic*
    1992;10 Issue 14

2.  Kocabey Y, Et al. The value of clinical examination versus magnetic
    resonance imaging in the diagnosis of meniscal tears and anterior
    cruciate ligament rupture*. J of Arthroscopic and Related Surg*
    2004;20:696-700.

3.  Rose NE, Gold SM. A comparison of accuracy between clinical
    examination and magnetic resonance imaging in the diagnosis of
    meniscal and anterior cruciate ligament tears. *J of Arthroscopic
    and Related Surg* 1996;12:398-405.

4.  Pookarnjanamorakot C Et al. Meniscal lesions in the anterior
    cruciate insufficient knee: the accuracy of clinical evaluation*. J
    Med Assoc Thai* 2004;87 No. 6.

5.  Scholten R, Et al. Accuracy of physical diagnostic tests for
    assessing ruptures of the anterior cruciate ligament: A
    meta-analysis*. J of Family Pract* 2003;52 No. 9.

6.  Terry GC Et al. Reliability of the clinical assessment in predicting
    the cause of internal derangements of the knee. . *J of Arthroscopic
    and Related Surg* 1995;11:568-576.

**[Ottawa Ankle Rules]{.underline}**

**Submitted by:**

**LCDR Joseph Strunce**

**joseph.strunce@ihs.gov**

Criteria for predicting ankle fractures in adults allowing for
insignificant fractures, defined as small avulsion fractures.

Ankle radiographs are required only if the patient has pain near the
malleoli and/or

1)  inability to bear weight immediately after the injury and four steps
    in ER

2)  bone tenderness at the posterior edge or tip of either malleolus.

In adults, the sensitivity for detecting significant malleolar fractures
was 100%.

For pediatric patients, radiographs are required only if the patient has
any of the following

1)  inability to bear weight immediately after the injury

2)  inability to bear weight for four steps in the ER

3)  tender deltoid ligament

If one or more of these factors were present, sensitivity for predicting
malleolar fractures was 93%.

**[Ottawa Knee Rules]{.underline}**

The Ottawa knee rules;

1)  age 55 years or older

2)  isolated tenderness of patella (no bone tenderness of knee other
    than patella)

3)  tenderness at head of fibula

4)  inability to flex 90 degrees

5)  inability to bear weight both immediately and in the ER for 4 steps

In adults, the sensitivity for detecting Knee fractures was 98.5%.

The Lachman's test is more sensitive (82% to 96%) and specific (97% to
100%) for ligamentous tears than is the drawer sign.

For meniscal tears, joint line tenderness is [sensitive]{.underline}
(85%) but not specific (29%), while the McMurray test is specific (98%)
but not sensitive (16%).

Exacerbation of osteoarthritis;

1.  age \>50 years

2.  morning stiffness \<30 minutes

3.  crepitus

4.  bony enlargement

89% sensitive and 88% specific for chronic arthritis.