Scapholunate Ligament Communicating Defects in Symptomatic and Asymptomatic Wrists

Abstract & Commentary

Synopsis: Communicating defects are seen in the scapholunate ligament of both symptomatic and asymptomatic patients. This study finds that a complete ligamentous disruption or involvement of the dorsal portion of the ligament may indicate a traumatic cause rather than a degenerative change.

Source: Linkous MD, et al. Radiology 2000;216:846-850.

Tears of the scapholunate ligament are a cause of radial-sided wrist pain. It is important to identify this lesion since it can be repaired. Many of these patients are referred for arthrography. It has already been shown that some communicating defects seen by arthrography can be asymptomatic and related to degeneration of the ligament with age.1,2 Because of this asymptomatic communication that can exist, some studies have deduced that wrist arthrography is poorly predictive of symptoms.1,3-5 Linkous and colleagues sought to determine whether the sizes and locations of scapholunate ligamentous communicating defects (SLLCDs) differed between symptomatic and asymptomatic groups, therefore helping to identify the more important and surgically correctable lesion.

Linkous et al reviewed the arthrographic data sheets, reports, and arthrograms of 213 consecutive patients who underwent bilateral wrist arthrography over a 15-month period at the Mallincrodt Institute of Radiology. Of these, 30 patients met the criteria of having wrist trauma and unilateral wrist pain, and they demonstrated at least one SLLCD. As is customary in this institution, a triple compartment arthrogram was also performed on the asymptomatic wrist when a communicating defect was found in the symptomatic wrist, resulting in 60 arthrograms. The location and size of each ligamentous defect was recorded. Differences between symptomatic and asymptomatic wrists were analyzed with the c2 or Fisher exact test.

Most communicating defects in both groups were incomplete and ranged from pinhole size to large. There was a higher frequency of complete disruption in the symptomatic wrists (9 [32%] of 28 wrists) than in the asymptomatic wrists (2 [10%] of 20 wrists; P = 0.092). Communicating defects involved the dorsal portion in 18 (64%) of the 29 symptomatic cases and in five (25%) of the 20 asymptomatic cases (P = 0.007). Only one patient in the whole series had an isolated communicating defect in the volar portion of the ligament.

Linkous et al concluded that a complete ligament disruption or involvement of the dorsal portion of the SLL may favor a traumatic etiology rather than degenerative change. There is some question as to whether defects at the lunate attachment are also related to trauma.

Comment by Lynne S. Steinbach, MD

This well-written paper looks at the characteristics of (SLLCDs) in symptomatic and asymptomatic individuals using multi-compartment arthrography. The goal of determining a difference in size and location of these defects between the two groups was met. The significantly greater percentage of communicating defects in the dorsal segment of the SLL in the symptomatic group may have been related to the fact that the tears were larger in that group or that symptoms would be more forthcoming in this heavily innervated region of the ligament. The lack of involvement of the volar portion of the ligament may be related to the reinforcing extrinsic ligaments in this area. Linkous et al raise the question about whether degenerative perforation can be symptomatic. This requires further investigation. Also, as Linkous et al point out, it may be that some of the defects that are asymptomatic in the population were the result of prior ligamentous trauma.

Linkous et al routinely perform bilateral triple compartment wrist arthrograms in patients with communicating ligament defects. This rigorous approach is not widely practiced in the radiology community, but it does add additional information about the significance of these defects if they are seen bilaterally in patients with unilateral wrist pain. This technique can provide valuable information for investigational studies such as this one.

I would suggest that magnetic resonance arthrography would be an excellent technique to further evaluate the hypothesis put forth in this paper. The multiplanar tomographic technique would allow one to precisely localize the defects. We would have to see how many patients would be willing to have both wrists evaluated in this manner!

References

1. Yin Y, et al. AJR Am J Roentgenol 1996; 166:
1067-1073.

2. Brown JA, et al. Can Assoc Radiol J 1994;45:292-296.

3. Herbert TJ, et al. J Hand Surg [Br] 1990;15:233-235.

4. Kirschenbaum D, et al. J Bone Joint Surg Am 1995; 77:1207-1209.

5. Manaster BJ, et al. J Hand Surg [Am] 1989;14: 466-473.