Exam of Boutoniere Injuries

- Chronic Injury:
    - flexion deformity of PIP & an extension deformity at DIP joint;
    - MCP hyperextension deformity;
    - after the central slip has been disrupted for some time, there will be volar migration of lateral bands, and contracture of oblique retaincular lig.
    - after the lateral bands have become contracted in a volar position, there will be limited flexion of the DIP joint when the finger is placed in MCP hyperextension and PIP hyperflexion (which puts lateral bands on maximum stretch);

- Acute Injury:
    - at initial presentation, PIP may appear to be a swollen & painful;
           - w/ time, manifestations of deformity (PIP flexion, DIP extension) appear;
    - w/ disrupted triangular ligament:
           - patients will not be able to actively extend PIP joint, but will be able to actively hold the PIP in extension, if it is first passively extended;
                 - this occurs because the lateral bands will relocate into their native position w/ PIP extension, allowing pt to hold finger in extension;
           - if it is unclear whether the central slip is disrupted, then test PIP joint extension w/ the wrist and MP joints held in flexion;
                        - this should relax the lateral bands;
    - w/ intact triangular ligament:
           - PIP joint may initially be capable of weak finger extension if the triangular ligament is intact;
           - active extension is possible because the triangular ligament holds the lateral bands in their native posiiton;
    - rupture of central slip must be differentiated from collateral ligament sprain;
           - pt will note tenderness on dorsum of finger rather than sides of joint;
           - loss of active PIP extension when MP is in extension and PIP is placed in 90 deg flexion;
           - weak extension against resistance = central slip injury;
           - extravasation of intra-articular dye dorsal and distal to PIP joint;
           - >15-20 deg loss of active extension at PIP joint w/ wrist & MCP flexed;
    - w/ acute injury the patient should at least be able to passively extend the PIP joint;
           - inability to extend the PIP joint passively, may indicated that the lateral bands have become trapped under the proximal phalanx condyles

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, September 24, 2012 12:04 pm