Darrach Procedure (Distal Ulna Resection)

21 Darrach Procedure (Distal Ulna Resection)

Indications

Rheumatoid disease with distal radioulnar joint (DRUJ) arthritis
Elderly, low-demand patients with DRUJ incongruity or positive ulnar variance (e.g., distal radial malunion)

Pitfall

Instability of the ulnar stump may develop resulting in radioulnar impingement. Younger patients may complain of weakness. Ulnar translation of the carpus may occur in rheumatoid patients.

Technique

Make a dorsal incision between the fifth and sixth extensor compartments.

Open the sixth dorsal compartment along its palmar edge.

Reflect the retinaculum radially to the 4–5 extensor compartment septum, and extract the EDQ tendon (Fig. 21-1).

Figure 21-1

Pearl

In the nonrheumatoid patient leave the retinaculum intact distal to the ulnar styloid to help maintain EDQ and extensor carpi ulnaris (ECU) stability.

Create a radially based, rectangular capsular flap with the distal limb just proximal to the dorsal radioulnar ligament, the ulnar limb in the floor of the sixth extensor compartment, and the proximal limb across the ulnar neck (Fig. 21-2).
Osteotomize the ulnar styloid through its base leaving the attachments to the triangular fibrocartilage complex (TFCC) intact.
Expose the ulnar head by subperiosteal dissection beginning at the floor of the sixth compartment.
Resect the ulnar head just proximal to the sigmoid notch (Fig. 21-3).
Create a distally based, rectangular flap of palmar DRUJ capsule and suture it to the dorsal aspect of the distal ulna with sutures placed through bone holes (Fig. 21-4).
Close the remaining DRUJ capsular tissue.
Transpose the retinaculum beneath the EDQ and ECU tendons (Fig. 21-5).