Radial Wrist Extensors as a Dynamic Stabilizers of Scapholunate Complex
Wrist stabilization is ensured by the complex of stabilizers, both static (intrinsic and extrinsic ligaments) and dynamic ones (flexor and extensor sinews of the wrist). Extrinsic carpal ligaments link both carpal rows with forearm, while the intrinsic ones connect individual carpal bones. From among intrinsic ligaments, the most significant from clinical point of view is scapholunate ligament (scapholunate lig. - SL). Instability of the SL resulting from SL ligament tear is the most frequent type of carpal instability. If untreated or undiagnosed, it may lead to destabilization of the carpal rows, and in the final stage to massive degenerative changes with SLAC (scapholunate advanced collapse). The aim of the study was to present a hypothesis of a possible influence of radial extensors of the wrist as dynamic stabilizers for SL complex, based on which it is possible to discern the partial ligament tear with accompanying damage of static stabilizers of the complex. Material and methods. This hypothesis was based on radiological tests carried out on 5 patients, with acute partial SL ligament tear, which was confirmed during wrist arthroscopy. The outcome was presented as well, with its visualization in radiological tests. Results. The picture of rotary subluxation of the scaphoid -signet ring sign in PA view and strengthening in stress position (clenched fist) was demonstrated in all 5 patients. In 2 patients who had wrist arthroscopy performed it was observed that the palmar and proximal part of SL ligament were injured, yet no damage of dorsal part was reported. In MRI tests of these patients, an additional injury of dorsal intercarpal ligament was revealed. Conclusions. Correction of the scaphoid reduction in position of clenched fist may result from influence of radial extensors of the wrist (both short and long) as dynamic stabilizers of SL complex. This imagining is a completion of the radiological symptoms so far occurring in this SL instability. In case of acute, partial scapholunate ligament tear, reduction of scapholunate subluxation and its internal fixation with the lunate and capitate for a 6-week period may be an optional procedure
- 1. Anatomy and Biomechanics Committee of the IFSSH. Position Statement: Definition of Carpal Instability. J Hand Surg 1999; 24A: 866-67.
- 2. Short WH , Werner FW , Green JK, Masaoka S: Biomechanical evaluation of the ligamentous stabilizers of the scaphoid and lunate: Part II. J HandSurg 2005; 30A: 24-34.[PubMed][WoS]
- 3. Trail IA, Stanley JK, Hayton MJ: Twenty Questions on carpal instability. J Hand Surg Eur 2007; 32: 240.[Crossref]
- 4. Żyluk A, Piotuch B: The management of scapholunate wrist instability: A review. Polish Orthopedicsand Traumatology 2012; 77: 83-89.
- 5. Żyluk A., Piotuch B., Mazur A: Niestabilność łódeczkowo-księżycowata nadgarstka - przegląd piśmiennictwa. Chir Narządów Ruchu i O rtop Pol 2011; 76(3): 175-81.
- 6. Garcia-Elias M: Carpal instability w: Green’s Operative Hand Surgery. VI wyd. Philadelphia: Elsevier 2010; 481-94.
- 7. Garcia-Elias M: Understanding wrist mechanics: a long and winding road. J Wrist Surg 2013; 2: 5-12.
- 8. Ozçelik A, Günal I, Köse N: Stress views in the radiography of scapholunate instability. Eur JRadiol 2005; 56(3): 358-61. Epub 2005 Jul 19.
- 9. Darlis NA, Kaufmann RA, Giannoulis F et al.: Arthroscopic debridement and closed pinning for chronic dynamic scapholunate instability. J HandSurg 2006; 31A: 418-24.[PubMed]
- 10. Linsceid RL , Dobyns JH, Beabout JW et al.: Traumatic instability of the wrist. Diagnosis, classification and pathomechanics. J Bone Joint SurgAm 1972; 54(8): 1612-32.
- 11. Talesinik J: The ligaments of the wrist. J HandSurg Am 1976; 1(2): 110-18.
- 12. Mayfield JK, Johnson RP, Kilcoyne RK : Carpal dislocations: pathomechanics and progressive perilunate instability. J Hand Surg Am 180; 5(3): 226-41.
- 13. Berger RA, Blair WF , Crowninshield RD et al.: The scapholunate ligament. J Hand Surg Am 1982; 7(1): 87-91[PubMed][Crossref]
- 14. Blatt G: Capsulodesis in reconstructive hand surgery. Dorsla capsulodesis for the unstable scaphoid and volar capsulodesis following excision of the distal ulna. Hand Clin 1987; 3(1): 81-102.
- 15. Cooney WP, Garcia-Elias M, Dobyns JH et al.: Anatomy and mechanics of carpal instability. SurgRounds Orthoped 1989; 10: 15-24.
- 16. Horii E, Garcia-Elias M, An KN et al.: A kinematic study of lunotriquetral dissociations. J HandSurg Am 1991; 16(2): 355-62.
- 17. Cooney WP, Linsceid RL , Dobyns JH: Carpal instability: treatment of ligament injuries of the wrist. Instr Course Lect 1992; 41: 33-44.[PubMed]
- 18. Brunelli GA, Brunelli GR: A new technique to correct carpal instability with scaphoid rotary subluxation: a preliminary report. J Hand SurgAm 1995; 20(3 Pt 2): S82-85.
- 19. Van Den Abbeele KL , Loh YC , Stanley JK et al.: Early results of a modified Brunelli procedure for scapholunate instability. J Hand Surg Br 1998; 23(2): 258-61.
- 20. Garcia-Elias M: Treatment of scapho-lunate instability. Ortop Traumatol Rehabil 2006 28; 8(2): 160-68.
- 21. Garcia-Elias M, Lluch AL, Stanley JK: Threeligament tenodesis for the treatment of scapholunate dissociation: indications and surgical technique. J Hand Surg Am 2006; 31(1): 125-34.[Crossref]
- 22. Harvey EJ, Berger RA, Osterman AL et al.: Bone-tissue-bone repairs for scapholunate dissociation. J Hand Surg 2007; 32A: 256-64.[WoS]
- 23. Szabo RM , Slater RR , Palumbo CF , Gerlach T: Dorsal intercarpal ligament capsulodesis for chronic, static scapholunate dissociation: clinical results. J Hand Surg 2002; 27: 978-84.
- 24. Janeta CL , An KN , Linsceid RL et al.: The role of the scapho-trapezial-trapezoidal ligament complex on scaphoid kinematics. W edycji: Schuind F, An KN, Cooney WP III i wsp. Advances in the Biomechanics of the Hand and Wrist. New York, NY: Plenum Pres; 1994: 345-61.
- 25. Salva-Coll G, Garcia-Elias M, Llusa-Perez M et al.: A The role of flexor carpi radialis muscle in scapholunate instability. J Hand Surg Am 2011; 36(1): 31-36.[Crossref]
- 26. Salva-Coll G, Garcia-Elias M, Leon-Lopez MT et al.: Effect of forarm muscles on carpal stability. J Hand Surg Eur Vol 2011; 36(7): 553-59.[Crossref]