Altman used recursive partitioning in the diagnosis of idiopathic osteoarthritis of the knee. The diagnosis can be made based on clinical, laboratory and radiological data. The author is from the University of Miami and Miami Veterans Administration Medical Center.
NOTE: The recursive partitioning is similar to CART (classification and regression tree) analysis.
Patient selection:
(1) presence of knee pain
(2) absence of a condition predisposing to degenerative arthritis (see Table I, page 33)
Parameters:
(1) osteophytes on joint X-ray
(2) synovial fluid (SF) findings
(3) duration of morning stiffness
(4) crepitus
Synovial fluid (SF) findings seen in osteoarthritis
(1) clear
(2) viscous
(3) WBC count < 2,000 per µL.
Osteophytes |
SF Findings |
Morning Stiffness |
Crepitus |
Group |
N |
0 or 1 |
|
|
A |
N |
2 or 3 |
> 30 minutes |
|
B |
N |
2 or 3 |
<= 30 minutes |
N |
C |
N |
2 or 3 |
<= 30 minutes |
Y |
D |
Y |
|
|
|
E |
Group |
Diagnosis |
---|---|
A |
no osteoarthritis |
B |
no osteoarthritis |
C |
no osteoarthritis |
D |
osteoarthritis |
E |
osteoarthritis |
Performance:
• The sensitivity is 94% and the specificity is 88% (page 37, text).
Age can be used as a surrogate marker if synovial fluid data is not available.
Osteophytes |
Age in Years |
Morning Stiffness |
Crepitus |
Group |
N |
<= 39 years |
|
|
A |
N |
<= 39 years |
> 30 minutes |
|
B |
N |
>= 40 years |
<= 30 minutes |
N |
C |
N |
>= 40 years |
<= 30 minutes |
Y |
D |
Y |
|
|
|
E |
Purpose: To evaluate a patient for idiopathic osteoarthritis of the knee using the recursive partitioning model of Altman with clinical, laboratory and X-ray data.
Specialty: Surgery, orthopedic, Immunology/Rheumatology
Objective: clinical diagnosis, including family history for genetics, imaging studies, criteria for diagnosis
ICD-10: M15, M19,