The use of screws in the treatment of scapholunate instability

Scapholunate injuries: challenging existing dogmas in anatomy and surgical techniques

The management of scapholunate injuries and dissociation remains debatable. Traditional methods of fixation had centred around open procedures, but advances in wrist arthroscopic techniques has redefined both major anatomical findings and operative approaches. This article challenges two main existing dogmas: first, the anatomy of the scapholunate ligament and second, the management of these injuries. For the first, we propose that scapholunate stability is in fact maintained by a whole anatomic complex, consisting of well-defined capsuloligamentous structures and extrinsic ligaments, and that the scapholunate ligament itself probably has a limited role. For the second, we challenge the notion that scapholunate injuries often require open procedures and propose that mini-invasive arthroscopic dorsal repair of the scapholunate complex is an efficient technique and sufficient for achieving long-term stability.

Role of wrist arthroscopy in scapholunate dissociation

Scapholunate ligament tear is most frequently encountered in the aftermath of trauma in supination and extension of the wrist. It generates chronic instability, leading to osteoarthritis. It may be associated with fracture of the distal epiphysis of the radius or of the scaphoid. These lesions are often difficult to diagnose, especially in early stages. Treatment of chronic scapholunate ligament lesions before onset of osteoarthritis is a challenge for the surgeon. To date, recommendations are for open reconstruction or repair, which can improve pain and grip strength, but very often at the cost of wrist stiffness. The advent of arthroscopy has completely changed the understanding and treatment of these lesions. The present review focuses on recent contributions to the anatomy of the scapholunate complex and the anatomopathology of these dissociations, and explores classical treatments and the emerging role of arthroscopy. We shall seek to answer five questions: (1) What are the anatomical bases of the scapholunate complex, (2) What is the initial clinical and paraclinical work-up for scapholunate dissociations, and how are they to be classified, (3) What are the classical treatments for scapholunate dissociation, (4) What are the technical principles and results of arthroscopic treatment, (5) What are the limits and perspectives of arthroscopic treatment?

Management of chronic scapholunate ligament injury

Scapholunate ligament is the most commonly injured ligament in the wrist and requires accurate diagnosis and treatment. It presents with pain, stiffness and can lead to carpal instability as well as degenerative arthritis if left untreated, with subsequent loss of function and disability. There are several management options currently available but there is no consensus on how best to manage a wrist with chronic sequelae of scapholunate ligament injury. This review explores available evidence in the literature on optimal treatment options including non-operative and operative procedures, relevant surgical techniques and their associated outcomes. A summary of the current concepts in the management of Chronic Scapholunate ligament injury is presented.

Surgical outcomes of chronic isolated scapholunate interosseous ligament injuries: a systematic review of 805 wrists

Background

Management of chronic isolated scapholunate interosseous ligament (SLIL) injuries has generated a substantial volume of low-quality literature with descriptions of multiple new surgical techniques, and the impact of instability pattern and the optimal surgical technique remain unclear. The primary goal of this review was to compare clinical, radiographic and patient-rated outcomes between current surgical techniques.

Methods

We performed a systematic literature search using multiple databases. We analyzed clinical, radiographic and patient-reported outcomes. We used a fixed-effects model weighted by sample size with combined outcomes estimated via least squares means with 95% confidence intervals. We also performed a subgroup analysis of static versus dynamic instability.

Results

We assessed 805 procedures from 37 study groups, with 429 procedures used in subgroup analysis. There were no statistically significant differences in outcomes between surgical techniques or in subgroup analysis. Overall, postoperative wrist flexion and pain scores decreased, and grip strength and patient-rated outcomes improved.

Conclusion

Compared to overall preoperative values, modest improvements in pain score, grip strength and functional outcome scores were obtained from a range of reconstructive procedures performed for chronic isolated SLIL injuries. No significant differences could be ascertained between surgical techniques, potentially owing to the low quality of evidence and procedure heterogeneity. This study provides accurate preoperative reference values for future studies, highlights the controversial clinical impact of instability classification, and the need for higher-quality multicentre or collaborative trials to improve our understanding and management of this common injury.

Reduction and Association of the Scaphoid and Lunate: A Functional and Radiographical Outcome Study

Background  Management of scapholunate (SL) ligament disruption is a challenging problem. The reduction and association of the scaphoid and lunate (RASL) procedure has been described with varying results. This study assessed the outcomes of the RASL procedure. Purpose  The objective of this study was to assess the outcomes of patients undergoing the RASL procedure at our institution in regard to pain relief, range of motion, radiographic and functional outcomes, complications, and reoperations. Materials and Methods  Twelve patients with symptomatic chronic SL instability underwent the RASL procedure. The mean age was 35 years. The mean time from injury to surgery was 40 weeks. The mean follow-up was 89 months. Outcomes included visual analog score for pain, wrist range of motion, grip strength, and Mayo Wrist Scores. Preoperative and postoperative radiographs were reviewed. Results  Pain scores improved in 10 wrists. Range of motion and grip strength worsened. The average Mayo Wrist Score was 63.3. The mean SL diastasis and angle improved, but seven wrists developed progressive degenerative changes, with two requiring a salvage procedure. Symptomatic progressive screw lucency occurred in eight wrists requiring screw removal. Conclusion  The RASL procedure can improve SL widening but has a high rate of early failure and reoperation. Following reoperation, long-term follow-up demonstrates reasonable long-term durability in some cases. Level of Evidence  This is a Level IV, therapeutic case study.

Arthroscopic Reduction-Association of the Scapholunate with an Absorbable Screw

Background  The treatment of chronic scapholunate instability is yet a controversial topic. Arthroscopic reduction-association scapholunate technique is a minimally invasive option in which a stable pseudoarthrosis at the scapholunate joint is obtained, allowing some degree of movement while maintaining the normal alignment of the wrist. The purpose of this study was to review the results of arthroscopic reduction-association scapholunate with an absorbable screw. Methods  We retrospectively evaluated patients with dynamic or static, but reducible, chronic scapholunate instability who underwent arthroscopic reduction-association scapholunate between 2012 and 2015. An absorbable headless compression screw was used in the technique. Results  A total of 33 patients (21 males, 12 females) were included. Average follow-up time was 17 months. At final follow-up, the average postoperative Disabilities of the Arm, Shoulder and Hand (DASH) score was 18 (range, 8-46). The average postoperative grip strength was 30 kg, 73% of the uninjured side. The average extension-palmar flexion arc was 112 degrees, 79% of the uninjured side. The scapholunate angle decreased from 70 degrees preoperatively to 52 degrees postoperatively. In the cases of static lesion, the scapholunate interval decreased from 4.1 mm preoperatively to 2.8 mm at final follow-up. One patient had a breakage of the screw at 4 months, four developed a complex regional pain syndrome, one had a prominence of the screw at the waist of the scaphoid, and four maintained symptoms of instability. From these 10 patients, 5 were submitted to revision surgery. Conclusion  The arthroscopic reduction-association technique is capable of maintaining the reduction of the scapholunate joint and of improving symptoms, while preserving range-of-motion. The use of an absorbable screw is an option in this technique, and may diminish screw-related complications.

Biomechanics of an Articulated Screw in Acute Scapholunate Ligament Disruption

Background  An injury to the scapholunate interosseous ligament (SLIL) leads to instability in the scapholunate joint. Temporary fixation is used to protect the ligament during reconstruction or healing of the repair. Rigid screw fixation-by blocking relative physiological motion between the scaphoid and lunate-can lead to screw loosening, pullout, and fracture. Purpose  This study aims to evaluate changes in scaphoid and lunate kinematics following SLIL injury and the effectiveness of an articulating screw at restoring preinjury motion. Materials and Methods  The kinematics of the scaphoid and lunate were measured in 10 cadaver wrists through three motions driven by a motion simulator. The specimens were tested intact, immediately following SLIL injury, after subsequent cycling, and after fixation with a screw. Results  Significant changes in scaphoid and lunate motion occurred following SLIL injury. Postinjury cycling increased motion changes in flexion-extension and radial-ulnar deviation. The motion was not significantly different from the intact scapholunate joint after placement of the articulating screw. Conclusion  In agreement with other studies, sectioning of the SLIL led to significant kinematic changes of the scaphoid and lunate in all motions tested. Compared with intact scapholunate joint, no significant difference in kinematics was found after placement of the screw indicating a correction of some of the changes produced by SLIL transection. These findings suggest that the articulating screw may be effective for protecting a SLIL repair while allowing the physiological rotation to occur between the scaphoid and lunate. Clinical Relevance  A less rigid construct, such as the articulating screw, may allow earlier wrist rehabilitation with less screw pullout or failure.

Update on operative treatment of scapholunate (SL) instability for radiologists: part 1-SL ligament repair, dorsal capsulodesis and SL ligament reconstruction

Scapholunate instability is the most common form of carpal instability. Imaging (especially radiography) plays an important role in the staging, management and post-operative follow-up of scapholunate (SL) instability. The goals of this article are to review the pre-operative staging of SL instability, the surgical options for repair and reconstruction of the SL ligament, along with the normal postoperative imaging findings as well as complications associated with these surgical options.

Injuries of the Scapholunate Interosseous Ligament: An Update

The scapholunate ligament is both a key ligament in the stability of the carpus and one of the most frequently injured. Thorough understanding of the anatomy, biomechanics, and pathophysiology of the wrist is important in treating injuries to the scapholunate ligament. The presentation of scapholunate instability often includes a vague injury history and pain with grip, wrist extension, and sport or labor. Identified injuries are classified based on dynamic and static radiographic findings, chronicity, and the presence or absence of arthrosis. Surgical options for the treatment of low- and high-grade injuries include both open and arthroscopic procedures and can be broadly classified into four categories: limited arthroscopic procedures, primary ligament repair, reconstructive procedures, and salvage procedures. No strong evidence currently supports any one treatment. Decision making is largely based on expert opinion and surgeon experience. Prognosis is often guarded, and patient expectations should be tempered.

Scapholunate Ligament Tears: Acute Reconstructive Options

Left untreated, scapholunate dissociation can lead to posttraumatic wrist arthritis. Multiple surgical procedures have been designed to reduce the scapholunate interval, restore normal wrist kinematics, and prevent the development of arthritis. Unfortunately, current surgical procedures have not been shown to consistently maintain radiographic alignment at long-term follow-up and result in decreased wrist range of motion and strength compared with the contralateral side. The purpose of this article is to review the current reconstructive options for scapholunate ligament tears without evidence of radiographic arthritis.

Chronic Scapholunate Ligament Injuries: Treatment with Supplemental Fixation

Treatment of chronic scapholunate ligament injuries can be challenging. Traditional reconstructive techniques, including varied capsulodeses and tenodeses often yield inconsistent results with loss of reduction and radiographic deterioration. As a result, supplemental hardware fixation has become more popular and may allow more robust stabilization of the scapholunate reconstruction. However, these procedures have complications and few data regarding outcomes are currently available. This article evaluates the role of supplemental fixation in the management of chronic scapholunate instability.

Chronic Scapholunate Ligament Injury: Techniques in Repair and Reconstruction

Although the true incidence of scapholunate interosseous ligament (SLIL) injury is unknown, a study found that 35% of cadaveric wrists had some degree of scapholunate tear. Of those wrists with SLIL injury, 29% had evidence of arthrosis. Early recognition and treatment of these injuries can delay or prevent the onset of arthritis. This article details treatment options for SLIL injury across the spectrum of pathology with a particular emphasis on chronic scapholunate repair and reconstruction. New techniques and outcomes data also are presented.

Chronic scapholunate instability treated with temporary screw fixation

PURPOSE

To determine the efficacy of scapholunate (SL) temporary screw fixation to maintain the reduction of SL interval after ligament debridement, repair, or reconstruction.

METHODS

A total of 36 patients who had chronic SL instability were included. Arthroscopic debridement was performed for dynamic instability, and primary repair or reconstruction of the SL ligament was performed for static instability. We then used SL screw fixation for the protection of the repair or reconstruction. Screws were removed when loosening was noted on x-ray.

RESULTS

The average patient age was 43 years. Eleven had dynamic instability, and 25 had static instability. The average follow-up was 7.9 years. Nearly 95% of the patients had no more than mild pain. The average ranges of movement of the wrist were 55° extension, 51° flexion, 26° ulnar deviation, and 15° radial deviation. Postoperative x-ray revealed an average SL angle of 56°. The average SL gap was 2.5 mm. Both of these radiographic parameters were maintained at final follow-up. Dorsal intercalated segmental instability (DISI) deformity was not corrected in 2 patients. One patient had avascular changes in the proximal scaphoid and lunate but remained asymptomatic at 7 years postoperatively. There was no further intercarpal and radiocarpal degeneration.

CONCLUSIONS

Temporary SL screw fixation together with arthroscopic debridement, ligament repair, or reconstruction provided a stable closure of the SL interval and satisfactory clinical and functional results along with a low incidence of complication.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Radiographic evaluation of the modified Brunelli technique versus a scapholunotriquetral transosseous tenodesis technique for scapholunate dissociation

PURPOSE

To compare reduction of the scapholunate articulation using a transosseous tenodesis through the scaphoid, lunate, and triquetrum (SLT) with the modified Brunelli technique (MBT) in a cadaver model, as measured by scapholunate (SL) angle and diastasis on radiographs.

METHODS

Twelve fresh-frozen cadaveric wrists were radiographically examined in a neutral posture, ulnar deviation, and clenched fist position. The SL angle and diastasis were recorded in each position with the SL ligament intact, after sectioning the ligament and secondary restraints, and after reconstruction by either the MBT (6 wrists) or SLT technique (6 wrists). Wrists were cycled through their maximum flexion and extension arc 100 times to simulate wrist motion after ligament sectioning and reconstruction.

RESULTS

After sectioning and cycling, all wrists demonstrated radiographic evidence of SL diastasis. After ligament reconstruction and cycling, there was no statistically significant difference in diastasis in the MBT reconstructions compared with the SLT reconstructions (3.0 vs 2.4 mm). The SLT group demonstrated better maintenance of the restored SL angle than the MBT reconstructions.

CONCLUSIONS

In this cadaveric model, both MBT and SLT reconstructions restored anatomic parameters in the SL joint, with correction of SL diastasis and SL angle. Future studies to assess the clinical outcomes of SLT tenodesis in patients with chronic SL disruptions are important.

CLINICAL RELEVANCE

The SLT tenodesis, with a central biologic tether along the SL axis and dorsal reinforcement, may prove clinically useful.

The path of screw insertion for stabilization of the scapholunate joint: a cadaveric study

The aim of this study was to determine the path of screw placement to avoid breaching the articular surface of both lunate and scaphoid bones at the radiocarpal and midcarpal joints. An Acutrak screw was inserted into the right scapholunate joint of ten cadavers starting immediately distal to the tip of the radial styloid and aiming for the tip of the ulnar styloid. The articular surfaces of the scaphoid and lunate bones in all ten cadavers were exposed and examined. A computed tomography (CT) scan of four wrists was performed. Eight of the ten cadavers had no perforation or destruction of the articular surfaces. Screw stabilization of the scapholunate joint can be performed without perforation or destruction of the lunate or scaphoid surfaces. We recommend that if this form of fixation is being used then the screw should be inserted commencing at the radial styloid tip and aiming for ulnar styloid tip, under radiological guidance.

Assessment of scapholunate instability and review of evidence for management in the absence of arthritis

Scapholunate ligament tear is a common wrist injury and may lead to degenerative arthritis of the wrist in the long term. We review the assessment and classification of scapholunate instability and discuss the findings from our search for evidence for the management of scapholunate instability in the absence of arthritis. Strong evidence (level 1 or 2) for management is lacking and published recommendations are largely experience-based. The choice of procedure in the absence of arthritis depends on the extent of the tear, quality of the ligament remnants, and reducibility of the joint. Prospective, randomized studies with validated outcome measures are needed to establish the efficacy of intervention on symptoms and function and its effect on the risk of future arthritis.

Current role of open reconstruction of the scapholunate ligament

This paper is a review of the various surgical techniques used in repair or reconstruction of the scapholunate ligament according to the clinical stages and anatomic-pathologic findings. Arthroscopy permits a direct evaluation of the scapholunate injury and the status of the articular surfaces. Specific indications for each type of scapholunate ligament tear are proposed, from the different types of dorsal capsulodesis to bone-ligament-bone techniques and tenodesis procedures. The authors' preferred techniques and literature review of the expected outcomes are presented.