Extensor Carpi Radialis Longus Tenodesis Using a Biotenodesis Screw for Treatment of Symptomatic Geissler 2 Scapholunate Dissociation

Abstract

Treatment of scapholunate dissociation (SLD) depends on the degree of injury. We present our technique of extensor carpi radialis longus (ECRL) tenodesis for Geissler grade 2 SLD and our preliminary results. After arthroscopic confirmation of Geissler grade 2 SLD, we use a single incision and a polyetheretherketone (PEEK) anchor, attaching half of the ECRL tendon to the scaphoid. Preliminary results include improvements in QDASH, QDASH (work) and QDASH (sports/music), a median satisfaction level of 4/5 (satisfied), and a low complication rate. Our method is a safe, reproducible, and effective treatment of symptomatic Geissler grade 2 SLD that has failed nonoperative management, with technical advantages over alternative methods in the literature.

Introduction

Scapholunate ligament injuries are the most common wrist ligament injury. 1 The scapholunate ligament is the primary stabilizer of the scapholunate complex, 2 with adjacent carpal ligaments playing a role as secondary stabilizers. 3 Damage to these stabilizers can cause scapholunate dissociation (SLD), the most common form of carpal instability. 4

The scapholunate ligament itself can be divided into three parts: dorsal, intermediary, and volar. Damage to the strongest, dorsal part will have a more significant effect on wrist biomechanics, especially if associated with injury to the secondary stabilizers.

Various classification systems have been developed to stratify the degree of SLD. Geissler et al developed a useful arthroscopic classification 5 ( Table 1 ).

Table 1. Geissler arthroscopic classification of scapholunate instability.

Grade	Description
1	Attenuation or hemorrhage of interosseous ligament as seen from the radiocarpal space. No incongruency of carpal alignment in the midcarpal space.
2	Attenuation or hemorrhage of interosseous ligament as seen from the radiocarpal space. Incongruency or step-off of carpal space. There may be a slight gap (less than the width of probe) between carpal bones.
3	Incongruency or step-off of carpal alignment as seen from both the radiocarpal and mid-carpal space. Probe may be passed through a gap between the carpal bones.
4	Incongruency or step-off of carpal alignment as seen from both the radiocarpal and mid-carpal space. There is gross instability with manipulation. A 2.7-mm arthroscope may be passed through a gap between the carpal bones.

Although untreated SLD can lead to dorsal intercalated segment instability (DISI) and subsequent wrist arthritis, 6 the natural history of scapholunate ligament injury is poorly understood, 7 in part due to heterogeneity in the degree of SLD.

Treatment depends on symptoms, degree of SLD, status of surrounding cartilage, and surgeon preferences. 8 Chronic and symptomatic low-grade SLD (Geissler 1 or 2), in which the ligament is irreparable but there is no DISI or arthritis, are the subject of heavy debate. 7 Several operative techniques have been described, including arthroscopic debridement and thermal shrinkage 9 or extensor carpi radialis longus (ECRL) tenodesis to the dorsum of the scaphoid. 10 11 12

We present our surgical technique for a modified, minimally invasive technique of ECRL tenodesis with a polyetheretherketone (PEEK) anchor for treatment of Geissler grade 2 SLD, with our preliminary results using this method.

Technique

All patients had magnetic resonance arthrographic findings of partial scapholunate ligament injury. All had persistent pain despite at least 6 months of nonoperative treatment comprising hand therapy, splinting, and injections. None had radiographic evidence of DISI deformity or arthritis.

Informed consent is taken for wrist arthroscopy and the possibility of proceeding to ECRL tenodesis based on the arthroscopic findings. The operation is performed under tourniquet, general anesthetic, and regional nerve blockade.

A diagnostic arthroscopy is performed. The radiocarpal joint is examined, and the intermediate scapholunate ligament is inspected closely. The midcarpal joint is then entered, and the scapholunate joint is probed to assess stability. Only if Geissler grade 2 SLD ( Fig. 1 ) and intact cartilage surfaces are found do we proceed to ECRL tenodesis, as described next.

Fig. 1.

View of midcarpal joint with scapholunate joint being probed.

A 5-cm curvilinear incision is made over the dorsum of the scaphoid, starting at Lister's tubercle and incorporating the 3–4 portal ( Fig. 2 ). Blunt dissection is performed down to the extensor retinaculum, sparing superficial radial nerve branches. The extensor pollicis longus (EPL) tendon is partially released from its compartment, allowing it to be retracted radially ( Fig. 3 ) and the ECRL tendon is identified.

Fig. 2.

Skin incision and underlying extensor retinaculum.

Fig. 3.

Extensor pollicis longus tendon retracted radially; extensor carpi radialis longus and extensor carpi radialis brevis tendons identified.

A limited dorsal capsulotomy is performed between EPL and ECRL ( Fig. 4 ), and the dorsum of the distal pole of the scaphoid is located. A 1.6-mm Kirschner wire is inserted in the distal pole of the scaphoid toward the scaphoid tubercle, and the wire position is checked with fluoroscopy ( Fig. 5 ). A 4-mm cannulated drill is used over the wire to a depth of 10 mm, and the drill hole position is checked with fluoroscopy ( Fig. 6 ).

Fig. 4.

Dorsal capsulotomy with dorsum of scaphoid visible.

Fig. 5.

Properly positioned Kirschner wire, lateral and posteroanterior view.

Fig. 6.

Properly placed drill hole, posteroanterior view.

The ECRL tendon is divided in half longitudinally, and the ulnar half is released distally. This is then held under tension and marked with methylene blue directly over the drill hole. A further mark is made 10 mm distally ( Fig. 7 ). The area between the marks represents the part of the tendon that will be inside the scaphoid tunnel.

Fig. 7.

Ulnar half of divided extensor carpi radialis longus with mark at level of drill hole and 10 mm distal.

The tendon end is sutured using a 2–0 Fiberloop suture (Arthrex) with a whip-stitch technique between the two marks from proximal to distal ( Fig. 8 ). Excess tendon distal to the marks is removed. The suture is then cut as close to the needle as possible to ensure sufficient length to pass through the introducer for the 4- × 10-mm PEEK Biotenodesis screw (Arthrex).

Fig. 8.

Whip-stitched tendon.

A Nitinol loop ( Fig. 9 ) is used to pull the suture through the introducer until the tendon is flush with the introducer tip ( Fig. 10 ), and the ends of the suture are then secured around the handle.

Fig. 9.

Suture ends through nitinol loop with screw loaded on introducer.

Fig. 10.

Tendon flush with introducer, ready for insertion.

The tendon is inserted into the drill hole with the introducer, and the PEEK anchor is advanced as an interference screw ( Fig. 11 ).

Fig. 11.

Screw being inserted with suture secured to introducer handle.

The final position is checked to ensure that the screw is not prominent ( Figs. 12 13 ) and the remaining suture is trimmed. After closure of capsule, subcutaneous tissue, and skin, the reconstruction is protected with a dressing and a volar plaster of paris splint.

Fig. 12.

Final position of screw and tendon.

Fig. 13.

Illustration of the extensor carpi radialis longus tenodesis final position.

The patient is discharged the same day. At 2 weeks, they are followed up for a wound check and conversion to a full cast for a further 4 weeks.

Discussion

Multiple operative techniques have been described for SLD. 4 Treatment depends on the degree of SLD and condition of the articular cartilage. 13 If there is no arthrosis and no fixed DISI deformity, soft tissue procedures are generally preferred to avoid fusion. 14 Some authors have advocated arthroscopic debridement with 9 or without 15 thermal shrinkage for Geissler grade 1 or 2 SLD. However, only 55% of patients returned to similar work as before the procedure 9 and 15% of patients had persistent pain requiring subsequent scapholunate ligament reconstruction. 15

A dynamic ECRL tenodesis is designed to enhance the extension forces on the scaphoid 11 without static tethering. It was first described in 2008 10 with a 3.5-mm screw fixing the ECRL tendon to the dorsum of the scaphoid and early results were positive. In 2017, a modification of the original technique, using a smaller incision, a 4-mm screw, and a spiked washer, was published. 11 Again results were positive; however, the complication rate was high. In particular, 43.5% of patients reported screw head impingement, requiring screw removal. We utilize an interference fit within a scaphoid tunnel, rather than compression against the scaphoid with the head of a screw (with or without a washer). The tendon therefore has a much greater contact area with bone, which may lead to better integration, and we have had no reports of impingement. Our only complication so far is one case of altered sensation on the dorsolateral aspect of the hand.

A further modification of the original technique was published in 2010, 12 in which the whole tendon is inserted into a hole in the scaphoid and secured with a suture knot over the scaphoid tubercle cortex. This technique requires a second, volar incision, and relies entirely on the knot and the cortex of the tubercle. Our technique requires only one incision, important given the edema after arthroscopy, and only half the ECRL tendon. Comparisons of suture anchor versus transosseous tunnel repair for quadriceps tendon rupture have shown anchors to be a biomechanically superior construct. 16

Our technique is quick and can be done following diagnostic arthroscopy. As the anchor can be safely drilled through, fixation of any future scaphoid fracture is not impeded and any potential future procedures such as partial fusion are not impeded.

We have also collected promising preliminary results in our initial patient cohort:

1. An improvement in mean QDASH 17 score from 53.9 (range: 27.3–68.2) to 12.59 (range: 0–32.5).

2. An improvement in mean QDASH work score from 56.9 (range: 25–100) to 8.76 (range: 0–37.5). All patients were able to return to their previous employment, including a forklift truck driver.

3. An improvement in mean QDASH sport/music score from 87.5 (range: 56.3–100) to 47.7 (range: 0–100).

4. On a 5-point Likert scale, 18 40% reported being “very satisfied” with the result of their operation; 20% were “satisfied” and the remaining 40% were “neither satisfied or dissatisfied,” resulting in a median satisfaction level of 4 out of 5 (satisfied) (range: 3–5).

Conclusion

Our method of ECRL tenodesis is a safe and reproducible treatment of Geissler grade 2 SLD, with persistent symptoms despite nonoperative management. It has shown promising preliminary results, with technical advantages over previously described methods in the literature including a reduced complication rate. Data from this technique in a larger patient cohort will be prospectively collected to study the long-term results.

Funding Statement

Funding None.