Lunotriquetral Ligament
Description
The lunotriquetral joint is stabilized by the lunotriquetral ligament (LTL), a C-shaped ligament with three components - dorsal, volar and proximal.[1][2][3] The LTL together with the scapholunate ligament, are the most important wrist interosseous ligaments because they join the proximal carpal row's surfaces, the volar and dorsal portions are considered true ligaments where the proximal portions are fibrocartilaginous membranes[2]. These proximal portions play no mechanical role, while the volar portion is the strongest and most important compared to scapholunate instability, lunotriquetral instability is less common.[2] The triquetrum and its ligaments are important for proprioception for neuromuscular wrist stabilization.[3]
Attachments
Proximal attachment: distal lunate and triangular fibrocartilage.
Distal attachment: medial margin for the triquetrum.
Function
Dorsal portion: limits dorsiflexion between the lunate and triquetrum.
Volar portion: largely contributes to carpal stability and also limits triquetral extension.
Mechanism of Injury / Pathological Process
Isolated LTL injuries can occur when a person falls onto an outstretched arm, while the wrist is in radial deviation and extension[1]. Repetitive stress can also lead to a LTL injury.[1][2] For more information regarding LTL injury and lunotriquetral dissociation, please see the lunotriquetral dissociation page.
Assessment
Following holistic history taking and physical examination of the LTL, the following clinical test should be considered.
- The Lunotriquetral Ballottement Test.
- The Kleinman’s shear test.
- The ulnar snuffbox test.
- The Click provocation test.
Treatment
Choosing the best treatment for LTL involves multiple factors of consideration, like the timing, stability, and the presence of associated injury.[4]First-line management of partly isolated LTL without dissociation should be non-operative, either with casting or immobilization with splint above the elbow.[5]Prescribed non-steroidal anti-inflammatory medications and corticosteroid injections may also be helpful.
For injuries that present with instability and tear unresponsive to conservative treatment, operative treatment and arthroscopic intervention are best used.[4]
Physiotherapy Management
Immobilization is the initial management of LTL injury, a careful splint molding with a pad under the pisiform bone will obtain an optimal alignment as the healing progresses.[4]After immobilization for 6 weeks with no positive outcome, the arthroscopic treatment will be considered.
Post Operative Management
Active and passive ROM commences immediately, edema control measures to prevent swelling also start. Once the operative sutures are removed, a long arm cast is done in the anatomical forearm rotation for 6 to 8 weeks. After 8 to 10 weeks once the pins are removed, the wrist can be supported with a splint, and strengthening exercises commence once the full ROM is restored.[4]
References
- ↑ 1.0 1.1 1.2 Beutel BG. Rehman UH. Konstanty J. Beeker RW. Carpal Ligament Instability. Treasure Island: Florida StatPearls. (2022).
- ↑ 2.0 2.1 2.2 2.3 Moser T, Khoury V, Harris PG, Bureau NJ, Cardinal E, Dosch JC. MDCT arthrography or MR arthrography for imaging the wrist joint? Seminar Musculoskeletal Radiology. 2009 Mar;13(1):39-54.
- ↑ 3.0 3.1 Van de Grift TC, Ritt MJ. Management of lunotriquetral instability: a review of the literature. Journal of Hand Surgery (European Volume). 2016 Jan;41(1):72-85.
- ↑ 4.0 4.1 4.2 4.3 Nicoson MC, Moran SL. Diagnosis and treatment of acute lunotriquetral ligament injuries. Hand Clinics. 2015 Aug 1;31(3):467-76.
- ↑ Reagan DS, Linscheid RL, Dobyns JH. Lunotriquetral sprains. The Journal of hand surgery. 1984 Jul 1;9(4):502-14.