Obligatory medical device diagnostics
- Radiographs of the affected joint [radiographic signs of arthritic joint remodeling: osteophytes (gonarthrosis: initially at the eminentia intercondylica), narrowed joint space, increased subchondral sclerosis and deformity; see below. Kellgren and Lawrence score]Note: Radiological changes rarely correlate with subjective complaints (here: hip pain): with a sensitivity of 36.7% and a specificity of 90.5%, the predictive value for radiology is only 6.0%.
Optional medical device diagnostics – depending on the results of the history, physical examination, laboratory diagnostics and obligatory medical device diagnostics – for differential diagnostic clarification.
- Computed tomography (CT; sectional imaging procedure (X-ray images from different directions with computer-based evaluation), particularly well suited for the depiction of bony injuries) of the affected joint – findings correspond to the X-ray images, but earlier depiction possible; better depiction of complex structures.
- Magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging method (by means of magnetic fields, that is, without X-rays); particularly well suited to the representation of soft tissue injuries) of the affected joint – indication mainly in cartilage and meniscus damage; Caveat (attention): cartilage defects in the knee are intraoperatively usually more extensive.
- Arthroscopy (joint endoscopy) – if necessary, small tissue samples of the damaged cartilage or synovial fluid (synovial fluid) are taken and examined in the laboratory. If loose bone fragments or cartilage pieces are found during the examination, they can be removed by lavage (irrigation) in the same procedure.
- Arthrosonography (ultrasound examination of joints) – this also reveals joint effusions, soft tissue processes and fluid accumulation in the joint. This examination is also performed before a puncture or injection. The joint effusions or fluid accumulations can then be treated with medication – if necessary also by puncture. Does not count among the methods of choice for osteoarthritis!
Nativradiological classification of osteoarthritis according to the Kellgren and Lawrence score
| Osteophytes | Joint space | Sclerosis | Deformation | Points |
| none or questionable | none or questionable narrowed | none | none | 0 |
| unique | unique | light | light | 1 |
| large | advanced | light with cysts | distinctly | 2 |
| cancelled | strong with cyst formation | 3 |
Interpretation
According to the Kellgren-Lawrence score, the radiological expression of osteoarthritis is divided into five grades:
- Grade 0 = 0 points
- Grade 1 = 1 – 2 points
- Grade 2 = 3 – 4 points
- Grade 3 = 5 – 9 points
- Grade 4 = 10 points
Grade 1: Minor subchondral sclerosis. No joint space narrowing or osteophytesGrade 2: Minor joint space narrowing and incipient osteophyte formation, implied joint surface irregularitiesGrade 3: Marked osteophyte formation, marked joint surface irregularitiesGrade 4: Marked joint space narrowing to complete destruction, deformity/necrosis of joint partners.
