4 Bowstringing
4.1 Patient History Leading to the Specific Problem
A 42-year-old professional male pianist presents with decreased active range of motion of the right long finger 2 months after a trigger finger A1 pulley release of the right long finger.
4.2 Anatomic Description of the Patient’s Current Status
The patient has a painful pulling sensation in the palm with motion of his right long finger. He has limited motion of the right long finger, metacarpophalangeal (MCP) joint 0 to 60 degrees, proximal interphalangeal (PIP) joint 0 to 30 degrees, distal interphalangeal (DIP) joint 0 to 45 degrees but full passive range of motion (▶Fig. 4.1a). The flexor digitorum profundus (FDP) and the flexor digitorum superficialis (FDS) of the right long finger are intact. Bowstringing of the flexor tendons is present over the proximal phalanx during resisted flexion. Magnetic resonance imaging (MRI) reveals volar displacement of the flexor tendons (▶Fig. 4.1b). The palmaris longus tendon is present in the right wrist when the patient opposes the thumb to the small finger while flexing the wrist against resistance.
4.3 Recommended Solution to the Problem
An A2 pulley reconstruction is recommended to prevent the flexor tendons from bowstringing. Various materials and surgical techniques have been described for pulley reconstruction. Free tendon grafts, extensor retinaculum, or artificial materials can be used in the reconstruction of pulleys. Free tendon autograft options include palmaris longus and extensor tendon. Various pulley reconstruction techniques can be utilized; some encircle (loop techniques) the proximal phalanx, while others do not. The reconstructed pulley must be strong, not only maintaining the flexor tendons close enough to volar surface of the phalanx but also allowing the flexor tendons to glide freely. Biomechanical studies have shown that the pulley reconstruction with the encircling techniques is stronger than the nonencircle techniques. However, the exact mechanical strength that a flexor pulley requires for active tendon motion is still unknown. Regardless of the technique used, the goal of the pulley reconstruction should be to recreate the length, tension, and glide of the native pulley. For this patient with bowstringing after trigger finger release, an A2 pulley reconstruction is performed using palmaris longus autograft.
4.3.1 Recommended Solution to the Problem
• A2 pulley reconstruction can prevent flexor tendons from bowstringing.
• Reconstruction of pulley can be performed with free tendon autograft, extensor retinaculum, or artificial materials.
• Pulley reconstruction can be performed with encircle and nonencircle techniques.
• Achieve the appropriate tension within the flexor pulley to maintain the flexor tendons close enough to volar surface of the phalanges, but also allowing the flexor tendons to glide freely.
• It is important to recreate the length, tension, and glide of the native pulley.
