Chapter 16 Volar Capsuloligamentous Suture as Treatment of Volar Midcarpal Instability
Introduction
Midcarpal instability as described by Lichtman et al in 19811 is a rare condition that occurs mainly in young people after a sport-related accident. Testing the midcarpal joint provokes significant painful clicking due to midcarpal pivot shift.2 In most patients, the pathophysiology of volar midcarpal instability is secondary to volar capsule–ligament injury due to stretching or avulsion of the arcuate ligament (the triquetrohamatocapitate and radioscaphocapitate ligaments) and the long radioulnar ligament (RUL) ( Figs. 16.1a, b and 16.2a, b ). Imaging reveals dorsal intercalated segment instability (DISI) tilting of the second row of carpal bones along with volar intercalated segmental instability (VISI) tilting of the first row.2
Treatment of volar midcarpal instability continues to be challenging because no method has been shown effective. Conservative procedures such as open ligament reconstruction or capsulodesis stabilize the joint but also cause significant stiffness.3,4 Palliative procedures have severe functional consequences, even though they are typically used as a last resort for these injuries. Arthroscopic thermal volar capsulorrhaphy has been described, but its use is limited to partial tears.5
Operative Technique
Patient Preparation and Positioning
Surgery is generally performed on an outpatient basis under regional anesthesia. The patient is placed supine, with the arm resting on an arm board with an attached tourniquet. A standard traction tower (5-7 kg) is used during the arthroscopic procedures.
First Phase: Arthroscopic Exploration
Using a dorsal approach with the scope in the 6R portal and hook probe in the 3–4 portal, arthroscopic radiocarpal joint exploration reveals loosening of the extrinsic volar ligament complex, especially the radioscaphocapitate (RSC) and long radioulnate (LRL) ligaments. Probe testing of these structures reveals significant loss of tension.
The radial midcarpal (MCR) and ulnar midcarpal (MCU) portals are used next. The volar aspect is often hidden under a thick synovial membrane that must be removed to inspect the volar ligaments. The volar arcuate ligament complex, which consists of the triquetrohamatocapitate (ulnar limb of the arcuate ligament) and radioscaphocapitate (radial limb) ligaments will often be avulsed or stretched ( Fig. 16.3a, b ). All of the ligaments are identified and their insertions abraded with a shaver.
Second Phase: Volar Ulnar Approach
The volar ulnar (VU) approach is carried out through a 2 cm longitudinal incision along the ulnar side of the flexor digitorum tendons over the proximal wrist crease ( Fig. 16.4 ).6 The flexor tendons are reflected to the radial side. A needle is inserted into the midcarpal joint at the level of the arcuate ligament under visual guidance with the scope placed in the MCR portal. This step can be facilitated by using an inside-out VU approach ( Fig. 16.5a, b ) (Chapter 2).