Arthroscopically Assisted Ligamentoplasty for Axial and Dorsal Reconstruction of the Scapholunate Ligament

Abstract

Scapholunate (SL) ligament injury is among the most common injuries of the intrinsic ligaments of the carpus. Arthroscopic treatment in complete and nonacute injuries has had poor results. These cases have typically been treated using open surgical techniques that require a broad dorsal approach and produce soft tissue impairment, which leads to reduced wrist mobility. The development of wrist arthroscopy techniques has allowed the treatment of complete and nonacute injuries of the SL ligament, without the disadvantages of open surgery, respecting the soft tissues and avoiding injury of the posterior interosseous nerve, in an attempt to preserve the proprioception of the wrist and the secondary dorsal stabilizers. This arthroscopically assisted technique reconstructs the SL ligament using a tendon graft placed between the scaphoid and lunate and complemented by the reconstruction of the dorsal portion of the SL ligament, with the aim of creating an axial and dorsal tendinous ligamentoplasty between both bones.

Scapholunate (SL) ligament injury is among the most common injuries of the intrinsic ligaments of the carpus, untreated, results in scapholunate advanced collapse wrist. Wrist arthroscopy techniques have achieved good results in acute or partial chronic injuries of the SL ligament.¹ However, in complete and nonacute injuries, the results have been less satisfactory. Open surgical techniques2, 3 require a broad dorsal approach producing soft tissue impairment, which leads to reduced wrist mobility. The development of wrist arthroscopy may allow the treatment of these injuries, avoiding the disadvantages of open surgery (Table 1).4, 5 The technique attempts reconstruction of the SL ligament using a tendon graft placed in the axis between the scaphoid and lunate and complemented by the reconstruction of the dorsal portion of the SL ligament, creating an axial and dorsal ligamentoplasty between both bones. The arthroscopy allows us to respect the soft tissues, and to avoid injury of the posterior interosseous nerve, in an attempt to preserve the proprioception of the wrist⁶ and the secondary dorsal stabilizers.

Table 1.

Advantages and Limitations of the Technique

Advantages

Limitations

•Arthroscopic management avoids the wide dorsal approach and soft tissue involvement to increase the range of joint mobility. •Avoids injury to the posterior interosseous nerve, which plays an important role in the proprioception of the wrist. •Respects the secondary dynamic stabilizers such as the dorsal intercarpal ligament and the dorsal radio-pyramidal ligament. •No interpose tissues or implants in the radiocarpal and midcarpal joint surfaces. •Reconstructs the major dorsal portion of the scapholunate ligament with a nonrigid biological repair.

•Demanding technique with a long learning curve. •Requires a great arthroscopic ability. •Requires an autograft tendon with donor-site morbidity. •Requires a specific equipment for arthroscopy.

Indications

The technique is indicated for patients with a recent subacute or chronic injury, with competent secondary stabilizers, and without cartilaginous involvement (dynamic scapholunate instability), as well as for cases with an easily reducible static instability as classified by Garcia-Elias et al.² Unreducible instability, lunotriquetral instability, and osteoarthritis in the radiocarpal or midcarpal joint will contraindicate the technique.

Surgical Technique

We employ the arthroscopic portals 3-4, 6R, midcarpal ulnar, and midcarpal radial, as well as two 1-cm small incisions, one at the anatomic snuffbox and another at the dorsal face of the wrist centered on the lunate (Fig 1). We use a 2.5-mm arthroscope (Arthrex, Naples, FL), a 2.9-mm shaver (Smith & Nephew, Andover, MA), and a wrist traction tower (Acumed, Hilsboro, OR).

Fig 1.

Portals and incisions used in the arthroscopically assisted axial and dorsal scapholunate reconstruction. We use the 3-4 and 6R portal and the MCR (midcarpal radial) and MCU (midcarpal ulnar) portal. Two small incisions are made, the first one at the anatomic snuffbox and the second one, dorsal, just over the lunate.

Diagnostic Arthroscopy, Preparation of the SL Ligament Space, and Reduction

Dry arthroscopy is performed. The SL ligament injury is classified from the radiocarpal and midcarpal portals (Video 1).

Geissler grade III to IV SL ligament injuries with integrity of articular cartilage and reducible carpus are suitable for the technique.

At this time, we perform cleaning of the fibrous and scar material that can exist in the scapholunate interval and hinder subsequent reduction.

Extraction and Preparation of Tendon Graft

As a tendon graft, we use the tendon palmaris longus of the homolateral forearm. We can also obtain a tendon band of the flexor carpi radialis, to approximately 2 to 3 mm thick, so that it passes freely through the buttonhole of the Graft Anchor (Arthrex) that is used to fix the graft, creating a tendon graft in 2 bands. A graft of 12 to 15 cm is usually sufficient.

Scapholunate Reduction and Placement of the Perforation Guide

A small incision is made at the anatomic snuffbox. Careful dissection separates and protects the neurovascular and tendon structures until reaching the scaphoid waist.

With arthroscopic visualization through the 3-4 portal, we introduce the tip of the C-shape guide (Arthrex SLAM Technique) through the 6R portal and place it in the proximal ulnar face of the lunate, directly in the lunotriquetral joint and centered on the anteroposterior depth of the lunate (Fig 2, Video 1). We introduce the cannulated end of the guide by radial incision. Under fluoroscopic visualization, we confirm the position of the tip end of the guide and adjust the cannulated end, placing it immediately proximal to the tubercle of the scaphoid in the anteroposterior projection and centered in lateral projection. Once both ends are guaranteed, the guide allows compression of the scapholunate joint through a ratchet mechanism. We reduce and compress the SL joint while moving the head of the capitate to volar, to assist with the reduction. If we do not achieve a satisfactory reduction, we place 2 Kirschner wires measuring 1.5 mm by way of a joystick.

Fig 2.

Arthroscopic visualization through the 3-4 portal; the tip of the C-guide is introduced through the 6R portal (arrow) and placed in the proximal ulnar face of the lunate, in the lunotriquetral joint, and centered on the anteroposterior depth. (L, lunate; R, radius; TFCC, triangular fibrocartilage complex.)

Setting, Placement of Guide Needle, and Conducting Osseous Tunnel

We introduce the guidewire through the guide, crossing the SL joint. We confirm anatomic reduction and the placement of the wire through fluoroscopy, verifying that the guidewire passes through the SL joint close to the midpoint or slightly distal and ends in the proximal ulnar corner of the lunate (Fig 3, Video 1), and is centered in lateral projection. With arthroscopic visualization, we confirm correct scapholunate reduction. A second wire is placed to stabilize the carpus and the guide. Later, we pass the cannulated drill 3.7 mm (Arthrex) over the central guidewire, perforating through the SL joint to the farthest corner of the lunate, avoiding to pierce the ulnar cortex of the lunate (Fig 3). After removing the bit and the guidewire, we wash the resulting tunnel of osseous remains with a long spinal needle.

Fig 3.

(A) With the wrist in horizontal position, introducing the guide wire through the C-guide. (B) Verifying the correct placement of the guide wire, through the scapholunate joint close to the midpoint or slightly distal until the proximal ulnar corner of the lunate. (C and D) Passing the cannulated drill over the central guide wire. (C) Under fluoroscopic control, we perforate through the SL joint to the farthest corner of the lunate, avoiding piercing the ulnar cortex of the lunate (arrow).

Introduction of the Tendon Graft in the Scapholunate Bone Tunnel

The tendon graft is introduced in the buttonhole making sure not to cover the anchor harpoons with the graft. We introduce the Graft Anchor (Arthrex) with the tendon graft of double beam through the sheath of the C-shape guide manually and smoothly until reaching the narrowest perforation hole of the lunate. The procedure concludes by impacting the graft from the ulnar side of the lunate with a hammer (Fig 4, Video 1). We confirm the position of the anchor by fluoroscopy; it should be near the proximal ulnar corner of the lunate and centered on the anteroposterior axis. We then remove the insertion device, and trim the wire secondary stabilizer to remove the guide.

Fig 4.

(A) Wrist in horizontal position. Introducing the Graft Anchor (Arthrex) with the tendon graft of double beam through the exterior sheath of the C-guide. (B) Impacting the graft from the ulnar side of the lunate with a hammer. (C) Confirming the position of the anchor by fluoroscopy (arrow). (D) Recovering the free ends of the graft, intra-articularly, from the radial incision to the dorsal and reanchoring it to the dorsal face of the lunate (arrow) using a Micro Corkscrew (Arthrex) anchor.

Setting the Plasty in Scaphoids and Reconstructing the Dorsal Portion

We examine the inlet orifice in the scaphoid to verify sufficient bone thickness in all directions to be able to introduce the interference screw of 4 mm × 10 mm PEEK (polyether ether ketone) (Arthrex) without risk of fracture. Applying traction to the free ends of the graft, the PEEK screw is placed in the hole of the scaphoid along with the tendon (Fig 4).

Through a dorsal 1-cm-long longitudinal incision, centered on the lunate, we recover the free ends of the graft with a grasper, intra-articularly, from the radial incision to the dorsal (Video 1) and reanchor it to the dorsal face of the lunate using a Micro Corkscrew anchor (Arthrex) (Fig 4). During this step, we perform an arthroscopic check (Fig 5, Video 1); in the radiocarpal joint, we inspect the entrance of the graft by the radial part of the scaphoid through the 3-4 portal, dismissing the protrusion of the interference screw and confirming the correct passage of the graft through the scapholunate dorsal face. Through midcarpal arthroscopy, we test the stability of the SL joint. We proceed to trim the excess graft and the dorsal capsular closure over the graft. We leave a Kirschner wire stabilizing the scaphoid with the capitate and conduct a final radiographic check (Fig 6).

Fig 5.

(A-C) Arthoscopic view from 3-4 portal, confirming the correct passage of the plasty through the scapholunate dorsal face (arrow). A (tendon graft), L (lunate), RS (radial styloid), S (scaphoid), SLL (scapholunate ligament). (D) Through midcarpal arthroscopy (scope at the midcarpal ulnar portal), testing the stability of the scapholunate joint and confirming the correct reduction. C (capitate), L (lunate), S (scaphoid).

Fig 6.

The concept of the axial and dorsal reconstruction of the scapholunate ligament, with 2-tailed tendon graft in the axis and the dorsal part of the graft reconstructing the dorsal part of the scapholunate ligament.

The result is a multiplanar reconstruction of the SL ligament with a central axis between the scaphoid and lunate and a tendon portion that recreates the major dorsal portion (Fig 6, Table 2).

Table 2.

Pearls and Pitfalls

1. The ideal indication would be patients with dynamic scapholunate instability. It can also be performed in cases with an easily reducible static instability.

2. Contraindications: unreducible instability, lunotriquetral instability, and osteoarthritis in the radiocarpal or midcarpal joint.

3. Dry arthroscopy is recommended. The tissue infiltration hampers any concomitant semiopen procedures because of loss of definition of anatomic planes.

4. The graft (PL or FCR) should be extracted from the longest possible length, although a graft of 12-15 cm is usually sufficient.

5. With the scope at the 3-4 portal, we introduce the tip of the C-shape guide through the 6R portal and place it in the proximal ulnar face of the lunate, directly in the lunotriquetral joint and centered on the anteroposterior depth of the lunate.

6. The C-shape guide allows compression of the scapholunate joint through a ratchet mechanism. We reduce and compress the SL joint while the guide wire is introduced.

7. A second Kirschner wire should be placed to stabilize the carpus and the C-shape guide.

8. We introduce the tendon graft in the buttonhole making sure not to cover the anchor harpoons with the graft. If that happens, the graft could be damaged or the anchor will not get fixed properly into the bone.

9. We must apply traction to the free ends of the graft to reduce the SL ligament interval when the interference PEEK (polyether ether ketone) screw is placed in the hole of the scaphoid.

10. We use the arthroscopy to confirm the correct passage of the graft through the SL ligament dorsal face. The correct placement of the graft reconstructs the dorsal part of the ligament and prevents the flexion and pronation of the scaphoid.

FCR, flexor carpi radialis; PL, palmaris longus; SL, scapholunate.

Complications

Although have not yet encountered any, we consider that the same complications may be found as in the other scapholunate reconstructive techniques (Table 3). The complications may be perioperative fractures during or after the performance of bone tunnels, avascular necrosis, and the possible complications from the arthroscopic portals and the incisions for the insertion of instruments.⁴

Table 3.

Complications and Prevention

Complications	Prevention
1. Perioperative fractures during or after the performance of bone tunnels.	1. Be very precise in the placement of the guidewire for milling tunnels.
2. Avascular necrosis of the tunneled bones.	2. Make small incisions with minimum opening of the joint capsule and continuous washing of the mill and tunnels.
3. Injury the branches of the superficial radial nerve, the radial artery, the cephalic vein, and the tendons of the first dorsal compartment.	3. Be careful with blunt dissection of the capsule and knowledge of the regional anatomy.
4. Recurrence of the initial injury due to distension of the graft and loosening of the fastening materials.	4. To be strict performing the technique, immobilization and rehabilitation protocols.

Postoperative Management

An antebrachial splint is placed allowing mobility of the fingers and elbow. At 4 weeks after surgery, the secondary Kirschner wire is removed and a removable orthotic is placed and the patient begin daily physiotherapy sessions.

Discussion

Reconstructive techniques have tried to restore the biomechanics of the SL ligament and normal carpal alignment.⁷ These techniques focus on reconstructing the dorsal portion of the SL ligament, which can lead to an increased distance in the volar portion and an alteration of the kinematics and load transmission. Nevertheless, good results have been published in less severe and short-term cases.3, 5

This technique uses a double autologous tendon graft placed in the axis of rotation between the scaphoid and lunate, fastened with an anchor at the proximal and ulnar edge of the lunate, accompanied by reconstruction of the dorsal portion of the SL ligament. Reconstruction of the dorsal portion adds more control to the dorsal translation of the scaphoid and a greater resistance to flexion and pronation thereof. The double clamping band helps to prevent SL ligament diastasis more effectively than a single reconstruction band. The objective is the creation of a multiplanar ligamentoplasty, which, although does not reconstruct the volar portion, introduces a nonrigid biological double tendon band in the scapholunate central axis that helps to stabilize the said portion and theoretically is a repair capable of adapting to the changes in the scapholunate axis throughout wrist movement in any plane.⁸ Another possible advantage is that the placement of the autograft is performed near the SL joint at both the lunate and scaphoid level, which manages to reduce the risk of recurrence of SL ligament diastasis by loosening of the fastening system over time.

Conclusions

This technique unifies the benefits of a multiplanar tendon reconstruction of the scapholunate interval, and allows us to respect the soft tissues injured in the traditional dorsal approach of open reconstructions. Despite being a recent technique, which we have only performed in 9 cases, the expectations and initial results allow us to be optimistic for the future, although it is necessary to perform the technique in more cases to obtain statistically significant results in comparative studies with other techniques.

Supplementary Data

Video 1

Arthroscopically assisted technique for reconstruction of the scapholunate (SL) ligament using a tendon graft placed in the axis between the scaphoid and lunate and complemented by the reconstruction of the dorsal portion of the SL ligament, creating an axial and dorsal ligamentoplasty. The arthroscopic portals 3-4, 6R, midcarpal ulnar, and midcarpal radial are used, as well as two 1-cm small incisions, one at the anatomic snuffbox and another at the dorsal face of the wrist centered on the lunate. The video shows a case of a right wrist surgery with complete tear of the SL ligament, dynamic scapholunate instability (Geissler 4 in arthroscopic assesment).