Clinical Relevance

Elsaidi and colleagues¹⁴ showed the importance of the DRCL on scaphoid kinematics through a series of sectioning studies. They sequentially divided the radioscaphocapitate, long radiolunate, radioscapholunate, and short radiolunate ligaments. They next divided the central and proximal scapholunate interosseous ligament (SLIL), then the dorsal SLIL, and finally the dorsal capsule insertion on the scaphoid. There was no appreciable change in the radiographic appearance of this wrist. When the DRCL was divided, a dorsal intercalated segmental instability deformity occurred.

In another series of biomechanical studies on ligament sectioning using 24 cadaver arms, Short and coworkers¹⁵ determined that the SLIL is the primary stabilizer of the scapholunate articulation, and that the DRCL, the dorsal intercarpal ligament, the scaphotrapezial ligament, and the radioscaphocapitate ligament are secondary stabilizers. They found that dividing the dorsal intercarpal or scaphotrapezial ligament alone followed by 1000 cycles of wrist flexion-extension and radial-ulnar deviation had no effect on scaphoid and lunate kinematics. Dividing the DRCL alone did cause increased lunate radial deviation when the wrist was in maximum flexion. Dividing the SLIL after any of the ligaments tested produced increased scaphoid flexion and ulnar deviation while the lunate extended. Short and coworkers¹⁵ also hypothesized that cyclic motion seems to cause further deterioration in carpal kinematics owing to plastic deformation in the remaining structures that stabilize the scapholunate.

These data provide a rationale for repairing the DRCL. The data also suggest that consideration should be given to augmenting the stability of the scaphotrapezial ligaments concomitant with treatment of the SLIL instability. Similar studies have established that the triangular fibrocartilage complex (TFCC) and the dorsal and volar radioulnar ligaments are primary stabilizers of the ulnocarpal joint.¹⁶ DRCL tears that are found during the arthroscopic treatment of ulnar-sided lesions are handled in a similar fashion.

Indications

Geissler and colleagues¹⁷ proposed an arthroscopic grading scale of interosseous ligament instability that has gained wide acceptance. In Geissler grade 1 and 2 lesions, there is no to minimal instability owing to ligament attenuation, but no tearing; these are synonymous with a dynamic instability. Grade 3 and 4 lesions represent partial and complete tears with greater degrees of carpal instability. This classification quantifies the resultant instability, and not the actual size of the tear. Based on this grading scale, an arthroscopic classification of DRCL tears is proposed in Table 51-1.

TABLE 51-1 Classification of Dorsal Radiocarpal Ligament Tears*

DRCL, dorsal radiocarpal ligament; LTIL, lunotriquetral interosseous ligament; SLIL, scapholunate interosseous ligament; TFCC, triangular fibrocartilage complex.

* The ligament with the highest Geissler grade determines the stage.

The treatment of DRCL tears is summarized in Table 51-2. An arthroscopic repair is indicated for isolated DRCL tears, which often leads to resolution of the wrist pain.^8,10 DRCL tears are commonly associated with SLIL tears or instability or both. Geissler grade 1 and 2 SLIL injuries are still amenable to arthroscopic treatment. In these situations, an arthroscopic repair of any associated DRCL tears is indicated because it may augment the coronal stability of the SLIL repair.^8–10 In open SLIL repairs, sagittal plane stability is often supplemented by adding a dorsal capsulodesis or using a tendon weave, such as the modified Brunelli procedure. Arthroscopic thermal shrinkage of the scaphotrapezial ligaments also theoretically may enhance the sagittal plane stability of the scapholunate joint. This is currently under investigation, but no data are available to recommend this procedure as yet.

TABLE 51-2 Treatment of Dorsal Radiocarpal Ligament Tears