Dorsal Extrinsic Ligament Injury and Static Scapholunate Diastasis on Magnetic Resonance Imaging Scans

Scapholunate Instability: Diagnosis and Management - Classification and Treatment Considerations - Part 2

Intervention for scapholunate instability is aimed at halting the degenerative process by restoring ligament integrity and normalizing carpal kinematics. Part 1 of this Current Concepts article reviewed the anatomy, kinematics, and biomechanical properties of the scapholunate ligament as well as its critical stabilizers. In this section, we provide a foundation for understanding the spectrum of scapholunate ligament instability and incorporate meaningful new anatomical insights that influence treatment considerations. These updates clarify the importance of the critical stabilizers of the scapholunate interval, ligament-specific considerations in scapholunate ligament reconstruction, and the risks of ligament disinsertion when surgically exposing the dorsal wrist. We propose a ligament-based treatment algorithm based on the stage of injury, degree and nature of ligament damage, and presence of arthritic changes.

Scapholunate Instability: Diagnosis and Management - Anatomy, Kinematics, and Clinical Assessment - Part I

Injuries to the scapholunate joint are the most frequent cause of carpal instability. The sequelae of these injuries account for considerable morbidity, and if left untreated, may lead to scapholunate advanced collapse and progressive deterioration of the carpus. Rupture of the scapholunate interosseous ligament and its critical stabilizers causes dyssynchronous motion between the scaphoid and lunate. Additional ligament injury or attenuation leads to rotary subluxation of the scaphoid and increased scapholunate gap. Intervention for scapholunate instability is aimed at halting the degenerative process by restoring ligament integrity and normalizing carpal kinematics. In the first section of this review, we discuss the anatomy, kinematics, and biomechanical properties of the scapholunate ligament as well as its critical ligament stabilizers. We provide a foundation for understanding the spectrum of scapholunate ligament instability and incorporate meaningful new anatomical insights that influence treatment considerations. The purpose is to provide an update regarding the anatomy of the scapholunate ligament complex, importance of the critical ligament stabilizers of the proximal carpal row, introduction of safe technique to surgically expose the scaphoid and lunate, as well as pathoanatomy as it pertains to the treatment of scapholunate dissociation. In the second section of this review, we propose a novel ligament-based treatment algorithm based on the stage of injury, degree and nature of ligament damage, and presence of arthritic changes.

Current Concepts in Scapholunate Instability Without Arthritic Changes

Scapholunate instability (SLI) is the most common carpal instability described. SLI leads to a degenerative arthritic pattern known as scapholunate advanced collapse (SLAC). Diagnosis of SLI can be challenging in pre-dynamic and dynamic stages. CT arthrogram, MR arthrogram and dynamic fluoroscopy are helpful in diagnosis while arthroscopy remains the gold standard. SLI is a multi-ligament injury, which involves not only the scapholunate interosseous ligament (SLIL) but also the extrinsic carpal ligaments. Hence, it is better described as an injury compromising the 'dorsal scapholunate(dSLL) complex'. A repair can be attempted for acute SLI presenting within 6 weeks of injury. Reconstruction is the mainstay of treatment for chronic SLI without degenerative changes. Multiple repair techniques have been described which include capsulodesis and tenodesis procedures. The clinical outcomes of the techniques have improved over the years. However, a common problem of all these techniques is the lack of long-term data on the outcomes and deteriorating radiological parameters over time. SLI staging is an important factor to be considered in choosing the reconstruction techniques for a better outcome. Currently, there is a trend towards more biological and less invasive techniques. Regardless of the technique, it is important to preserve the nerve supply of the dorsal capsuloligamentous structures of the wrist. Arthroscopic techniques being minimally invasive have the advantage of less collateral damage to the capsuloligamentous structures. Rehabilitation involves a team approach where a protected dart thrower's motion is allowed after a period of immobilization. Strengthening SL-friendly muscles and inhibiting SL-unfriendly muscles is a key principle in rehabilitation.

An algorithmic diagnostic approach to scapholunate ligament injuries based on comparison of X-ray examinations and arthroscopy in 414 patients

Conventional X-ray imaging is usually the first diagnostic assessment after clinical examination in case of suspected scapholunate interosseous ligament (SLIL) injury. Nevertheless, there is no consensus on the norms of the scapholunate distance (SLD) or carpal angles. Therefore, we aimed to determine the utility of static and dynamic radiographs in the diagnostic of an SLIL injury in comparison with the reference standard arthroscopy. We retrospectively analyzed the preoperative X-ray series and surgical records of arthroscopies of 414 patients. Radiological assessment included conventional static X-rays in the posteroanterior (PA) projection, clenched fist views in ulnar and radial deviations, in which the SLD at the midportion of the scapholunate (SL) joint was measured. The scapholunate angle (SLA) and radiolunate angle (RLA) were measured on lateral wrist radiographs. Receiver operating characteristic (ROC) curves were created to determine possible cut-off points of the radiological indices for the diagnosis of SLIL injury. Further, a logistic regression with the parameters having the highest area under the curve (AUC) was calculated. We found that SLD in ulnar inclination (AUC= 0.774), SLD in PA projection (AUC = 0.748), and SLA (AUC = 0.737) had the highest diagnostic value. The AUC of the combination of these three parameters was 0.822 for all patients with any SLIL lesion and 0.850 for patients with SLIL lesions of 3-4 Geissler grade. Further investigation of SLIL pathology would be appropriate in the case of SLD in ulnar inclination of 2.7 mm, SLD in PA projection of 1.9 mm and SLA of 63°.

The Dorsal Ligament Complex: A Cadaveric, Histology, and Imaging Study

PURPOSE

The distinction between the dorsal intercarpal (DIC) and dorsal scaphotriquetral (DST) ligaments is imprecise and unclear in the literature. The purpose of our cadaveric study was to define the origins, insertions, and anatomic relationships of the dorsal wrist ligaments and relate these anatomic findings to magnetic resonance imaging (MRI) scans and histology.

METHODS

The study included 17 unmatched fresh-frozen cadaveric specimens (7 male and 10 female), with a mean age of 67.1 years (range, 48-86 years). Wrists with arthritis or carpal malalignment were excluded. Ligaments were dissected and insertion sites were recorded in the radioulnar (width) and proximodistal (length) dimensions, centered at the midpoints of the insertion. Three cadaveric specimens underwent a histologic analysis to demonstrate ligament composition and insertion sites. Three additional cadavers underwent MRI, from which 3-dimensional models were built to model ligament topography.

RESULTS

The conjoined triquetral insertion of the DIC, DST, and dorsal radiocarpal (DRC) measured 88.5 ± 6.4 mm². In each specimen, there were 2 distinct deep and superficial components of intercarpal fibers. The deep component inserted on the lunate with an area of 59.0 ± 5.0 mm². The deep and superficial components diverged as they coursed radially. The superficial component proceeded to the scaphoid ridge, trapezium, and trapezoid, whereas the deep component inserted on the proximal row. The deep fibers blended distally from their lunate insertion with the DST, forming a robust, 2.9 ± 0.8-mm wide extension over the dorsal capitate. The DRC inserted on the lunate, proximal to the DIC and DST insertions, with an area of 23.9 ± 5.4 mm².

CONCLUSIONS

The dorsal ligament complex forms a firm link across the proximal carpal row and the DST provides extension of the proximal row over the capitate.

CLINICAL RELEVANCE

This information can guide surgeons while performing a dorsal approach to the wrist and repairing traumatic ligament disruption.

Traumatic Nondissociative Carpal Instability: A Case Series

PURPOSE

We report 8 cases of acute or subacute unilateral nondissociative carpal instability (CIND) in the context of nondisplaced scaphoid fractures.

METHODS

Eight patients from 3 centers developed abnormal volar intercalated segment instability (VISI) or dorsal intercalated segment instability (DISI) following the diagnosis of a nondisplaced scaphoid fracture. An operative inspection in each patient confirmed intact scapholunate and lunotriquetral interosseous ligaments. We outline the demographic characteristics of our patient cohort, radiologic and operative findings of CIND-DISI and CIND-VISI, and the outcomes of acute and delayed treatment.

RESULTS

Two patients were diagnosed with CIND-DISI and 6 with CIND-VISI associated with ipsilateral nondisplaced scaphoid fractures. The average time from injury to diagnosis of CIND was 11 weeks, and the mean clinical and radiographic follow-up was 18 months. Rapid healing of the scaphoid fractures was achieved in all patients (4 open reduction internal fixation, 4 cast). All patients underwent surgery to improve proximal carpal row alignment: in 3 of the 4 patients who were diagnosed and treated surgically within 12 weeks of injury, the radiolunate angle (RLA) was successfully restored. A contracture release and ligament repair or reconstruction with tendon graft 12 or more weeks following injury was unsuccessful in restoring proximal row alignment in all 4 patients. Two patients in the delayed treatment group required secondary surgery for partial fusion.

CONCLUSIONS

Based on the arthroscopic, imaging, and operative findings, we propose that the ligamentous restraints to CIND-VISI are dorsal at the radiocarpal joint and volar at the midcarpal joint. Conversely, the ligamentous restraints to CIND-DISI are dorsal at the midcarpal joint and volar at both the radiocarpal and midcarpal joints. In our series, a delayed diagnosis and late reconstructive surgery were associated with no improvement in RLA. We recommend early recognition of traumatic CIND and prompt treatment of injured ligaments prior to the development of a fixed deformity.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Wrist Trauma: More Than Bones

Acute and subacute wrist trauma predominantly consist of fractures of the distal radius in elderly patients and most frequently carpal fractures (scaphoid, followed by triquetrum and hamatum) and avulsion fractures of the ulnar styloid in younger patients, especially in sports-related injuries but also in work activities. The initial radiographs may miss the fractures and result when untreated in complications as nonunion, osteonecrosis, and degenerative osteoarthritis.

Fractures of the distal radius and of the scaphoid may be associated with ligament injuries, most frequently the scapholunate complex, which are often overlooked at the emergency department. Patients without osseous injuries may present intrinsic and extrinsic ligament tears that may lead to carpal instability when they are clinically and/or radiologically missed.

Therefore, in acute and subacute setting, computed tomography may be helpful for the detection of subtle fractures, and magnetic resonance imaging, for the early diagnosis of occult fractures and ligament injuries.

Carpal Instability: II. Imaging

Beyond clinical examination, the various forms of carpal instability are assessed with radiologic methods and arthroscopy. For this purpose, the imaging demand for spatial and contrast resolution is particularly high because of the small ligamentous structures involved. The entities of carpal instability are classified into degrees of severity. Early (dynamic) forms of instability can either be indirectly detected with X-ray stress views and cineradiography or by direct visualization of ruptured ligaments in high-resolution magnetic resonance (MR) imaging and MR or computed tomography (CT) arthrography, with the latter the standard of reference in imaging. Advanced (static) forms of carpal instability are sufficiently well detected on radiographs; visualization of early carpal osteoarthritis is superior on CT. To prevent disability of the hand, the radiologist has to provide an early and precise diagnosis. This case-based review highlights the imaging procedures suitable for detection and classification of carpal instability.

Extrinsic and Intrinsic Ligaments of the Wrist

Carpal stability depends on the integrity of both intra-articular and intracapsular carpal ligaments. In this review, the role of the radial-sided and ulnar-sided extrinsic and intrinsic ligaments is described, as well as their advanced imaging using magnetic resonance arthrography (MRA) and contrast-enhanced magnetic resonance imaging (MRI) with three-dimensional (3D) scapholunate complex sequences and thin slices. In the last decade, the new concept of a so-called "scapholunate complex" has emerged among hand surgeons, just as the triangular ligament became known as the triangular fibrocartilage complex (TFCC).The scapholunate ligament complex comprises the intrinsic scapholunate (SL), the extrinsic palmar radiocarpal: radioscaphocapitate (RSC), long radiolunate (LRL), short radiolunate (SRL) ligaments, the extrinsic dorsal radiocarpal (DRC) ligament, the dorsal intercarpal (DIC) ligament, as well as the dorsal capsular scapholunate septum (DCSS), a more recently described anatomical structure, and the intrinsic palmar midcarpal scaphotrapeziotrapezoid (STT) ligament complex. The scapholunate (SL) ligament complex is one of the most involved in wrist injuries. Its stability depends on primary (SL ligament) and secondary (RSC, DRC, DIC, STT ligaments) stabilizers.The gold standard for carpal ligament assessment is still diagnostic arthroscopy for many hand surgeons. To avoid surgery as a diagnostic procedure, advanced MRI is needed to detect associated lesions (sprains, midsubstance tears, avulsions and chronic fibrous infiltrations) of the extrinsic, midcarpal and intrinsic wrist ligaments, which are demonstrated in this article using 3D and two-dimensional sequences with thin slices (0.4 and 2 mm thick, respectively).

ATHLETE TEARING AND REHABILITATION CHARACTERISTICS

ABSTRACT Introduction: The speed and quality of functional recovery after knee cruciate ligament reconstruction directly affect the training effect and competition results of athletes. Objective: To evaluate the effect of early systematic rehabilitation after reconstruction of ligament tears in outdoor sports athletes. Methods: In this study, Liu Mou, an outstanding player of the national men's rugby team, was selected as the experimental object. A rehabilitation training program was adopted, and rehabilitation began from 2 to 5 weeks after reconstruction. Results: After the recovery of the first stage for 4 weeks, the knee extension Angle of the injured limb in Liu's sitting position reached 180 degrees. In the second stage of rehabilitation physical training, the body composition test showed that body fat decreased from 20.8% before rehabilitation to 16.3%. At the end of the third stage of physical training, he could complete the high flip. Conclusions: Through different stages of postoperative rehabilitation physical training, Liu's physical condition fully recovered to a higher level. He could then participate in normal football training and return to the game, indicating that Liu's rehabilitation training after anterior cruciate ligament reconstruction is effective. Level of evidence II; Therapeutic studies - investigation of treatment results.

Interdisciplinary consensus statements on imaging of scapholunate joint instability

Objectives

The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique.

Methods

Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors’ clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of ‘0’, ‘5’ and ‘10’ reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of ‘8’ or higher for 80% or more of the panellists.

Results

Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available.

Conclusions

Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability.

Key Points

• Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability.

• Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability.

• Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

Carpal Instability: I. Pathoanatomy

The pathoanatomy of carpal instability is multifactorial and usually complex. A thorough medical history and clinical examination are essential, as well as profound knowledge of the specific instability patterns. The stability of the wrist is ensured by the carpal joint surfaces, by intact intra-articular (particularly the scapholunate interosseous ligament) and intracapsular ligaments, and by crossing extensor and flexor tendons, the latter making the proximal carpal row an "intercalated segment." An important classification feature is the distinction between dissociative and nondissociative forms of carpal instability. Among others, scapholunate dissociation, lunotriquetral dissociation, midcarpal instability, and ulnar translocation are the most common entities. Early forms of instability are considered dynamic. In the natural course, static instability of the wrist and osteoarthritis will develop. This review focuses on the pathoanatomical fundamentals of the various forms of carpal instability.