Dorsal Capsulodesis

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CHAPTER 48 Dorsal Capsulodesis

Robert M. Szabo, MD, MPH

Rationale and Basic Science Pertinent to the Procedure

Scapholunate dissociation is the most frequently diagnosed pattern of carpal instability.¹ If left untreated, it leads to scapholunate advanced collapse and progressive painful arthritis of the wrist.² Treatment for scapholunate dissociation remains controversial and has varied from limited wrist arthrodeses³^–⁶ to soft tissue procedures, including dorsal capsulodesis⁷^–¹¹ and scapholunate interosseous ligament reconstruction using tendon graft.¹²^–¹⁴

Soft tissue reconstructions have several theoretical advantages that make them attractive alternatives to other procedures. In contrast to arthrodeses, soft tissue reconstructions preserve more intercarpal motion, including scaphoid flexion and extension with radial and ulnar wrist deviation. Arthrodeses limit motion. The scaphotrapeziotrapezoid limited arthrodesis results in a loss of 16% to 45% of wrist flexion, 25% of wrist extension, and 45% of radial deviation.³^–⁶ Scaphocapitate arthrodesis, also advocated for scapholunate dissociations, has been shown to produce similar reductions in wrist range of motion and in relative intercarpal motion to scaphotrapeziotrapezoid arthrodesis.¹⁵ There has been a renewed interest in tendon reconstructions^12,¹⁴; however, historically early results, although promising, have not stood the test of time.¹³

With a dorsal capsulodesis procedure, which is a soft tissue procedure rather than an arthrodesis, greater intercarpal motion is preserved, including scaphoid flexion and extension with radial and ulnar wrist deviation. Blatt ⁷ popularized the capsulodesis using a radius-based flap of wrist capsule inserted into the distal pole of the scaphoid. That procedure has been reported to result in a significant decrease in wrist flexion by some investigators, however, including Blatt, who reported a mean loss of 20 degrees of flexion.^7,¹⁶ Although it corrects the flexed posture of the scaphoid by crossing the radiocarpal joint and tethering the scaphoid, it nevertheless fails to correct the diastasis between the scaphoid and lunate seen radiographically.

Seeking to address these problems, we developed the dorsal intercarpal ligament capsulodesis (DILC) for the treatment of scapholunate dissociation based on the dorsal intercarpal ligament of the wrist. In a cadaver model, we tested our hypothesis that the DILC can restore the scapholunate relationship with improved wrist range of motion and function.¹⁷ In our model, the scapholunate interosseous ligament was sectioned, and the results of the DILC were compared with the results of a Blatt capsulodesis.¹⁷ To perform the capsulodesis using the dorsal intercarpal ligament, a 5-mm strip of the portion of the ligament that inserts onto the trapezoid was dissected free. The dorsal intercarpal ligament has some fibers that insert onto the dorsal ridge of the scaphoid, but none that insert onto the distal pole of the scaphoid; the remainder of the ligament inserts onto the trapezoid. The scaphoid and lunate were reduced anatomically. The prepared dorsal intercarpal ligament was rotated proximally on its origin from the triquetrum, stretched as tightly as possible, and held in position with a forceps. The ligament was secured to the distal pole of the scaphoid with a suture anchor (Figs. 48-1 and 48-2).

FIGURE 48-1 A and B, Dorsal intercarpal ligament capsulodesis from a dorsal perspective. The dorsal intercarpal ligament is elevated from its insertion on the trapezium and trapezoid (A), rotated proximally, and secured to a previously prepared bony trough in the distal pole of the scaphoid (B) using a suture anchor and additional nonabsorbable sutures as needed.

(From Szabo RM, Slater RR Jr, Palumbo CF, et al: Dorsal intercarpal ligament capsulodesis for chronic, static scapholunate dissociation: clinical results. J Hand Surg [Am]. 2002; 27:978-984.)

FIGURE 48-2 A and B, Dorsal intercarpal ligament capsulodesis from a lateral perspective. A, After the dorsal intercarpal ligament is elevated, the scaphoid is rotated back into normal alignment with the trapezium. B, The completed ligament transfer is shown. The soft tissue reconstruction is reinforced with Kirschner wires for the first 8 weeks after surgery.

(From Szabo RM, Slater RR Jr, Palumbo CF, et al: Dorsal intercarpal ligament capsulodesis for chronic, static scapholunate dissociation: clinical results. J Hand Surg [Am]. 2002; 27:978-984.)

DILC restored the normal scapholunate relationship more completely than did a Blatt capsulodesis. After a Blatt capsulodesis, the scapholunate diastasis remained significantly increased (P < .05) compared with the intact specimens when the wrist was placed in radial deviation, ulnar deviation, and the clenched fist position. In contrast, there were no significant differences in scapholunate gap between the intact specimens and DILC in any wrist position. In addition to the differences seen when comparing the intact group with each reconstructed group, there were significant differences between the two reconstructed groups. In the clenched fist position, in which the repair is stressed maximally, there was a significant increase in the scapholunate diastasis measured after a Blatt capsulodesis compared with DILC (5.8 ± 1.07 mm versus 3.1 ± 1.03 mm; P < .05). Similar significant differences were noted between reconstruction methods when the wrist was in extension and radial deviation. Both reconstruction techniques reduced the scapholunate angle. The scapholunate angle decreased more after DILC than after Blatt capsulodesis in all conditions except flexion, in which they were equal; however, the differences were not statistically significant owing to lack of power of the study.