Radiographic progression to dorsal intercalated segment instability

Review of surgical treatment for chronic scapholunate ligament reconstruction: a long-term study

PURPOSE

Scapholunate dissociation (SLD) is a common entity encountered by hand surgeons. While multiple methods for surgical treatment exist, there is little agreement on the best surgical techniques to treat chronic, static SLD. Our study's goal was to assess the long-term (greater than five years), clinical and radiologic outcomes of the currently recommended treatment options for chronic, static SLD.

METHODS

We performed a review of the literature to assess outcomes after surgical treatment of chronic, static SLD with long-term follow-up of greater than five years.

RESULTS

We found only six studies that encompassed the modified Brunelli tenodesis, capsulodesis, scapholunate arthrodesis, and bone-ligament-bone graft using the modified Cuenod procedure. All were level of evidence IV. Many patients went back to some form of work. Tenodesis showed less development of arthritis and greater improvement in scapholunate gap, while capsulodesis showed greater postoperative flexion and extension. Of note, study size varied with 67 combined patients in the capsulodesis studies and 30 patients in the tenodesis studies.

CONCLUSION

There was no clear superiority of one procedure over the others. More long-term data are needed to identify the best surgical treatment of chronic, static SLD.

Scapholunate Interosseous Ligament Anatomy and Biomechanics

Injury to the scapholunate interosseous ligament is one of the most common causes of carpal instability and can impart considerable compromise to the patient's hand function. However, the management of scapholunate ligament injuries remains a dynamic concept, especially with regard to the multitude of options and techniques that exist for its surgical treatment. We present a thorough review of scapholunate anatomy and morphology, and the role of the scapholunate articulations in the kinetics and pathomechanics of wrist instability. We also review the current literature on the biomechanical properties of the scapholunate ligament and its subcomponents. A sound understanding of the anatomy and biomechanics of the scapholunate ligament can clarify its instability and may better orient current reconstructive procedures or pioneer better future techniques.

Radiographic evaluation of a novel horizontal dorsal intercarpal capsulodesis as a treatment of pre-arthritic scapholunate dissociation: a cadaver study

Dorsal capsulodesis is an important part of the treatment of pre-arthritic scapholunate instability. We designed an experimental study using 14 fresh-frozen cadaver wrists to demonstrate the efficacy of a new horizontal dorsal intercarpal capsulodesis. We sectioned the scapholunate ligament to create a scapholunate dislocation. Several radiographic views, static and 'in stress', were recorded and we statistically compared the scapholunate interval before and after the section of the scapholunate ligament, and after the creation of the capsulodesis. The results showed a significant decrease of the scapholunate interval after the creation of the capsulodesis, especially in neutral and maximal ulnar deviation of the wrist. They also proved that our cadaveric model is reliable. This study demonstrated that this novel capsulodesis reduces the scapholunate interval in a cadaveric model.

Scapholunate instability: current concepts in diagnosis and management

Injuries to the scapholunate joint are the most frequent cause of carpal instability and account for a considerable degree of wrist dysfunction, lost time from work, and interference with activities. Although it is insufficient to cause abnormal carpal posture or collapse on static radiographs, an isolated injury to the scapholunate interosseous ligament may be the harbinger of a relentless progression to abnormal joint mechanics, cartilage wear, and degenerative changes. Intervention for scapholunate instability is aimed at arresting the degenerative process by restoring ligament continuity and normalizing carpal kinematics. In this review, we discuss the anatomy, kinematics, and biomechanical properties of the scapholunate articulation and provide a foundation for understanding the spectrum of scapholunate ligament instability. We propose an algorithm for treatment based on the stage of injury and the degree of secondary ligamentous damage and arthritic change.

Carpal bone postures and motions are abnormal in both wrists of patients with unilateral scapholunate interosseous ligament tears

PURPOSE

The recent ability to measure 3-dimensional in vivo carpal kinematics has facilitated the noninvasive study of complex carpal bone motion.

METHODS

In this study we examined the flexion/extension carpal kinematics of both wrists in 8 patients with unilateral scapholunate interosseous ligament (SLIL) tears by using computed tomographic (CT) imaging and a markerless bone registration technique. Carpal bone neutral posture and flexion/extension motion of both wrists of the injured patients were compared with the same parameters in wrists of 10 uninjured male and female volunteers (normals).

RESULTS

The neutral posture of the injured scaphoid and lunate were significantly more extended than those of normals. In these patients, however, the postures of the scaphoid and lunate in the contralateral uninjured wrists also were abnormal and were similar to those of the injured wrist. In addition, extension of the lunate and flexion of the scaphoid in both the injured and uninjured wrist were significantly different from normal but not different from each other.

CONCLUSIONS

This study was unable to attribute altered carpal posture and motion to SLIL tears because abnormalities were found in both wrists of patients with unilateral injury. The etiology of abnormal wrist kinematics in the asymptomatic wrist of patients with unilateral tears of the scapholunate ligament is not known.

Current status of scapholunate interosseous ligament injuries

Injuries to the scapholunate complex present the surgeon with both diagnostic and treatment dilemmas. The anatomic features, biomechanical properties, radiographic appearance, and surgical treatment algorithms of this small but structurally and kinematically important joint continue to be refined. A thorough history and physical examination, combined with a radiographic evaluation that can include plain radiographs, tomography, motion studies, arthrography, or MRI, usually will define the nature of the ligament injury. Arthroscopy is considered the gold standard for complete evaluation of scapholunate interosseous ligament injury and often is performed as a first step before repair or reconstruction. Procedures such as carpal fusions or capsulodesis can limit excessive scaphoid motion, promote wrist stability, and potentially prevent arthritis, but advances continue to be made in direct scapholunate interosseous ligament reconstruction. Challenges for the future involve improving noninvasive evaluation, defining the degree of extrinsic ligament injury, and improving direct repair and reconstruction.