Darrach Procedure

Darrach procedure is removal of distal ulna. It was first performed by Darrach in 1911 in New York City. Darrach Procedure is done for-

• For relief of pain following distal RU disruption and/or RU arthritis;
• For symptomatic malunion of Colle fracture in elderly patients, especially when stiffness is present

Darrach  procedure is generally performed on elderly patients with low functional demands. Young pts with symptomatic instability of distal radio ulnar joint  may have better results with distal radial osteotomy and with restoration of length & alignment, or when this is not possible then consider hemi-resection arthroplasty.

Technique of Darrach Procedure

Darrach procedure is performed by  dorsal approach by longitudinal incision is made over distal ulna. It involves resection of 1-2 cm of  ulna.

Frequently, Darrach procedure is performed in conjunction with other procedures such as inflammatory arthropathies.  In this situation, the surgical incision is usually dorsal midline longitudinal, which enables all aspects of the wrist reconstruction like wrist fusion, arthroplasty, tenosynovectomy, tendon transfer etc.

If the Darrach procedure is to be performed independently, a single oblique or chevron dorsal approach is made  overlying the fifth dorsal compartment.

A  capsulotomy deep to the fifth dorsal compartment  is performed.

Osteotomize the distal ulna using a power oscillating saw just proximal to the sigmoid notch. Keep resection to 2 cm or less.

Intraoperative fluoroscopic guidance is frequently helpful to assist with the location of the osteotomy.

Entire styloid should be removed with the distal ulna.

Idea is to resect the minimum possible he least amount of bone is excised which is sufficient to restore full motion. If ulna appears unstable after resection, it may be stabilized  by tendon of extensor carpii ulnaris.

Complications

• Instability of the distal ulnar shaft
• Painful subluxation of the exteensor carpii ulnaris over the transected end
• Palmar or ulnar subluxation of the carpal  bones
• Radio-ulnar impingement (Bones converge together)