In acute injuries, the first step is assessment and grading of the lesions. The patient is operated under regional anesthesia. With the patient in a supine position and the arm resting on an arm table, the elbow is flexed to 90°. A vertical traction of 5–7 lb is applied. In this way, the wrist can be analyzed at the same time by arthroscopy and fluoroscopy. We can also control the reduction and stabilization of the scapholunate injury. The joint is insufflated with 3–5 cc of normal saline. An abnormal passage of fluid from the radiocarpal joint to the midcarpal is already an indicator to an underlying lesion of the scapholunate ligament. The trocar and the arthroscope are introduced through a standard 3-4 radiocarpal portal. Care should be taken while inserting the trocar in order to avoid damage to the cartilage. The 4-5 or the 6R radiocarpal portal is used for passing a hook probe or instruments. It is possible to switch the position of the arthroscope and instruments at any time. The wrist is systematically examined starting from the radial side to the ulnar side. A lesion of the scapholunate ligament may not be properly appreciated until it is palpated/tested with the probe. The arthroscopic examination is then performed in the midcarpal joint. The arthroscope is introduced through radial midcarpal portal. Particular attention is paid to the dorsal edge of the scaphoid, which is in an abnormal anatomical position in case of complete scapholunate dissociation. In small wrists, it may be easier to insert the arthroscope through an ulnar midcarpal portal. A thorough examination of the radiocarpal and the midcarpal joints will reveal any injury to the scapholunate ligament. The ability to insert a probe/scope between the scaphoid and the lunate bones, the existence of a gap between the two bones, and the existence of a step-off between the lunate and the proximal pole of the scaphoid are all indicative of a rotational instability.

The normal ligament has a smooth and slightly concave bulge that is seen perfectly in the radiocarpal space. Often this normal concave aspect becomes convex when the ligament is traumatized and becomes weakened. Normally, there is a close contact between the scaphoid and the lunate without any step-off when seen through the midcarpal portals. With the scapholunate ligament intact, it is impossible to pass a probe from the midcarpal joint to the radiocarpal joint or vice versa. In the midcarpal joint, the position of the dorsal edge of the scaphoid is also examined. With increasing severity of scapholunate ligament injury, this tends to move into palmar rotation. GEISSLER [2] has described an arthroscopic classification of carpal instabilities. In stage I (Fig. 11.4), radiocarpal examination reveals a loss of the normal concave appearance of the scapholunate ligament, which then appears convex. This marks the beginning of weakening of the scapholunate interosseous ligament. A midcarpal examination in stage I reveals a normal and congruent SL aspect without any step-off.

In GEISSLER stage II lesions (Fig. 11.5), radiocarpal arthroscopy reveals an SL ligament that appears convex as in stage I. However, midcarpal joint arthroscopy reveals a loss of congruence the scapholunate space. The scaphoid begins to flex and the dorsal edge is rotated relative to the lunate resulting in a slight step-off between the scaphoid and the lunate bones.

In GEISSLER stage III (Fig. 11.6), radiocarpal arthroscopy reveals damage to the SL ligament that begins in the midportion and extends toward the dorsal part. Often we begin to see an abnormal space between the scaphoid and lunate. A probe can be passed through the scapholunate space and into the midcarpal joint. Often a remnant of the scapholunate ligament remains attached to the lunate. Midcarpal joint examination reveals an abnormal discrepancy between the scaphoid and lunate with a step-off. A 2 mm probe can easily pass through the space between the scaphoid and lunate.

In GEISSLER stage IV (Figs. 11.7 and 11.8), the ligament is completely torn. A 2.7 mm arthroscope can pass without difficulty from the radiocarpal joint to the midcarpal joint or back through the space between the scaphoid and the lunate (“Drive Through Sign”). There is usually no continuity of the ligament between the scaphoid and the lunate at this stage.

Patients with acute stage II or III lesions are ideal candidates for treatment by arthroscopic reduction and stabilization. The principle of treatment is to reduce the lunate and scaphoid in normal alignment and stabilization with K-wires. Under fluoroscopic control and longitudinal traction, the arthroscope is placed in the 3-4 radiocarpal portal. 1.5 mm × 10 mm K-wires are inserted percutaneously taking care not to damage the sensory cutaneous branches of the radial nerve. Leverage between the head of the capitate and the posterior horn of the lunate can provide a satisfactory reduction. Sometimes K-wires in the scaphoid and the lunate used as joysticks can control the rotation of the carpal bones. Normally 2 or 3 K-wires are placed across scapholunate space (Fig. 11.9). The K-wires are left buried under the skin and the patient is immobilized in a below-elbow splint. Ideally, the pins are removed at 8 weeks postoperatively. Rehabilitation of the wrist is commenced after removal of the K-wires and the recovery of normal mobility and strength usually requires 3 months approximately.

In GEISSLER stage IV lesions, repair by conventional open surgery is classically described. The incision passes between the third and fourth dorsal extensor compartments. The extensor pollicis longus is released from its compartment and retracted radially. The extensor digitorum tendons are retracted medially. The dorsal capsule is opened. The dorsal portion of the scapholunate ligament is repaired using small anchors and a non-absorbable suture and the repair is protected with K-wires passed from the scaphoid into the lunate. Typically, a radial dorsal capsular flap is fixed to the lunate with the aid of a small anchor. The dorsal capsule is meticulously repaired. The K-wires are usually left for 8 weeks, when they are removed before starting rehabilitation.

The treatment of chronic scapholunate ligament injuries poses the most difficult challenge for hand surgeons. In fact, untreated chronic scapholunate instability eventually leads to arthritic changes in the long term [3, 4]. Very often the diagnosis is delayed and is made at an advanced stage in which arthritic changes have already set in making salvage procedures imperative and precluding sporting activities, especially among athletes. The importance of treating these injuries as soon as possible cannot be overemphasized.

Numerous reconstruction techniques have been described in literature [5–27]; however they all result in loss of mobility in an attempt to restore the stability of the SL joint.

Recently a new technique of arthroscopic repair of the dorsal capsule-ligamentous portion of the SLIOL has been described to treat all stages of acute and chronic SL ligament injuries, with encouraging results [28]. The advantage of this new technique appears to be the preservation of mobility compatible with sporting activities. Some professional athletes with chronic, severe injury to the scapholunate ligament were able to resume their sporting activities.