Kinematic changes in elbow osteoarthritis: in vivo and 3-dimensional analysis using computed tomographic data.

PURPOSE

To investigate in vivo 3-dimensional kinematics in elbow osteoarthritis. We hypothesized that normal kinematics is preserved in an osteoarthritic elbow with a normal radiocapitellar joint (OAN). Conversely, we hypothesized that an osteoarthritic elbow with radiocapitellar degenerative changes (OAD) would show an abnormal kinematics pattern. Furthermore, the differences in osteophyte formation between groups may affect elbow kinematics.

METHODS

We examined 7 normal elbows, 7 OAN elbows, and 9 OAD elbows. We investigated 3-dimensional kinematics using computed tomography registration techniques. The osteophyte location was determined using 3-dimensional bone models generated from computed tomography data.

RESULTS

The kinematics is different in OAN and OAD elbows. In the OAN group, the ulna changed by 11° from a valgus to a varus position during elbow flexion and demonstrated a 4° change in the axis of elbow motion, similar to that in normal elbows. Osteophytes formed medially on the olecranon fossa. In the OAD group, the ulna changed by 4° varus during flexion from the 90° position, but only by 2° valgus during elbow extension from 90°. The change in the axis of elbow motion was 9°. Additional osteophytes formed on the anteromedial and lateral trochlea, lateral olecranon fossa, and medial olecranon of the ulnotrochlear joint, and on the radiocapitellar joint.

CONCLUSIONS

Normal kinematics was preserved in the OAN group. The OAD group demonstrated marked changes in the direction of elbow motion in the extension range, and the valgus motion pattern during extension was decreased.

CLINICAL RELEVANCE

The results of the current study provide a good starting point for further research into the nature of arthritic progression in the elbow joint and the role of debridement arthroplasty.