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Year |
2001 |
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Question Number |
39. |
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Category |
Select |
Question
A basketball player sustained a blunt trauma to his long finger. Examination reveals swelling and tenderness at the PIPJ. He is able to extend the digit and flex the PIP and the DIP joints. When the PIPJ is bent 90 degrees over the edge of the table and middle phalanx extension is blocked, the DIPJ goes into rigid extension when the patient attempts to extend his finger. Management should consist of
1. Surgical repair of the oblique retinacular ligament
2. Surgical repair of the central slip
3. A dynamic extension outrigger splint
4. Buddy Taping and early active motion
5. Extension splinting of the PIPJ
Figures
Answer (click for answer)
Answer: 5
Explanation: I recommend reading this classic article. It will do a much better good than I can of explaining the test. You need to know your anatomy of the extensor hood with regards to the central slip, the lateral bands, and the ways in which flex and extension of the DIP and PIP joints is controlled. Quickly, the central slip holds the lateral bands in place. All three arise from the extensor digitorum communis tendon. As the PIPJ and DIPJ are flexed, the extensor hood moves distally; the lateral bands will subluxate volarly on either side of the finger, and the finger in effect will lengthen during flexion. The conical shape of the head of the proximal phalanx allows for this motion. The lateral bands will return to the dorsal position with extension.
In a normal individual, when the PIPJ is bent 90 degrees over the table the central slip will be pulled distally and the terminal ends of the lateral bands will be slack. Therefore when resisted extension is attempted, the examiner will feel the contraction of the extensor hood and the intact central slip, and the DIPJ will stay flail.
When performing this test on the injured patient, the lateral bands will be pulled taut by the PIPJ flexion and will be volar to the joint axis. Now the lateral bands are EXTENSORS of the DIPJ. When the patient attempts to extend the PIPJ, the lateral bands will contract and cause extension across the DIPJ.
Reference: Elson RA: Rupture of the central slip of the extensor hood of the finger: A test for early diagnosis. JBJS Br 1986; 68:229-231.