Injury to the Scapholunate Complex: Shouldn't We Look at the Problem the Other Way Round?

Dear Editor,

Lesions of the scapholunate complex represent a varied spectrum of lesions due to the different ligament structures involved and the subtle biomechanics of the carpus.[1] As a result of this biomechanical instability, the scaphoid and lunate will cause joint conflicts, leading to carpal osteoarthritis in the long term. Garcia-Elias, by answering five questions, has provided a classification of Scapholunate (SL) instability that can guide a decision-making algorithm based on the known evolution of scapholunate instability[2]:

• Is it a partial or total lesion?

• Is the SL ligament repairable?

• Are the radiological angles normal?

• Is scaphoid subluxation reducible?

• Is the cartilage intact?

This classification takes a step back from the lesion itself and considers instability as a whole, as well as its consequences. It will thus enable us to propose therapeutic solutions based on repair, reconstruction, or palliative treatment, depending on the lesions found. In 2013, members of the European Wrist Arthroscopy Society (EWAS)/International Wrist Arthroscopy Society (IWAS) detailed “predynamic” lesions, visible only under arthroscopy. This classification seems to detail the scapholunate lesion rather than simply observing SL instability.[3] This study will add further detail to the classification originally published, describing for the first time the so-called predynamic lesions.[4] However, recent studies show that, contrary to what the two previous studies suggest, the appearance of radiological instability does not seem to correlate with a linear evolution of the lesion stage. To date, no study has proven that one stage of SLI precedes the other, or vice versa. In a cohort of around 100 patients considered to be at EWAS stage 3 or 4, almost 72% of patients had radiographically visible instability.[5] These findings do not respect the linearity established by the two previous classifications. In addition, certain situations are not included in the Garcia-Elias et al algorithm, such as the management of radiologically visible deformities without osteoarthritis or pain. Scapholunate instability can therefore appear in a multitude of configurations, without necessarily following an evolutionary linearity.[6] At present, there are no studies to confirm that radiological scapholunate instability will necessarily lead to degenerative wrist pain.

Our view is that treatment should not be based solely on the type of lesion, but rather on looking at the problem “the other way round.” To this end, the anagram SAWI (inverse of IWAS) provides a clear therapeutic proposal and helps the reader to decide on a surgical indication. “S” for the presence of symptoms seems to be the basis of any management, “A” with the appearance of altered radiological angles and thus of the deformity, “W” for the status of the wrist (arthritic? reducible?) and, lastly, I for the scapholunate lesion. As each stage progresses, we offer different therapeutic suggestions, based on our experience. This approach is the opposite of lesion-specific treatment but focuses on the patient, his or her complaints, and his or her instability. This letter is simply a thought and an invitation to take a step back from scapholunate instabilities and that each scapholunate lesion is different from the others, depending on the overall situation. Because radiological angles may be altered in so-called predynamic cases, it seems difficult to attribute a linearity of therapeutic strategy.[5] Further studies on the evolution of scapholunate instability need to be undertaken to better understand it. The wrist surgeon will have to take all these elements into account, to take his vision away from the microscope (the lesion) and look further through a telescope (the whole situation).

Publication History

Received: 05 August 2023

Accepted: 05 September 2023

Article published online:
13 October 2023

• References

• 1 Tham SK, Ek ET. The scapholunate dilemma. J Wrist Surg 2021; 10 (06) 465-466
• 2 Garcia-Elias M, Lluch AL, Stanley JK. Three-ligament tenodesis for the treatment of scapholunate dissociation: indications and surgical technique. J Hand Surg Am 2006; 31 (01) 125-134
• 3 Messina JC, Van Overstraeten L, Luchetti R, Fairplay T, Mathoulin CL. The EWAS classification of scapholunate tears: an anatomical arthroscopic study. J Wrist Surg 2013; 2 (02) 105-109
• 4 Dautel G, Goudot B, Merle M. Arthroscopic diagnosis of scapho-lunate instability in the absence of X-ray abnormalities. J Hand Surg [Br] 1993; 18 (02) 213-218
• 5 de Villeneuve Bargemon JB, Mathoulin C, Levadoux M, Dubian R, Jaloux C, Merlini L. Are we correctly assessing scapholunate injuries under arthroscopy?. J Plast Reconstr Aesthet Surg 2022; 75 (10) 3877-3903
• 6 Chim H, Moran SL. Wrist essentials: the diagnosis and management of scapholunate ligament injuries. Plast Reconstr Surg 2014; 134 (02) 312e-322e