Excision of the Distal Pole of the Scaphoid and the Midcarpal Joint

Abstract

Background Excision of the distal pole of the scaphoid is used to treat arthritis of the scaphotrapezial trapezoid (STT), radioscaphoid joint, and arthritis following scaphoid nonunion. Some patients develop midcarpal instability limiting utilization of this technique. Why some wrists develop postoperative instability while others do not, remains unclear.

Questions/Purposes To identify the wrists prone to developing midcarpal joint instability we evaluated the effect of midcarpal joint structure on force transfer through the wrist, we hypothesized that the force transfer will be further altered when a distal pole excision is performed and that midcarpal joint structure will affect force transfer.

Patients and Methods We used finite element analysis based on 19 computer tomography wrist scans. Nine type 1 (lunate has a facet with the capitate alone) and 10 type 2 (lunate has facets with both the capitate and hamate) models were prepared. A 200 N force was evenly split and applied to the dorsal crests of the trapezoid and capitate (100 N along each crest) to replicate the performance of a knuckle push-up. Displacement of the trapezoid, trapezium, scaphoid, capitate, and hamate was measured along each axis after the applied load. The simulation model was used to predict motion at the capitate and STT joint with excision of the distal pole.

Results Excision of the distal pole of the scaphoid affected the transfer of forces significantly (∼200% all bones in all directions) in all wrists. There are significant differences in force transfer between type 1 and type 2 wrists in the amount of force transferred (type 1 > type 2), in the percent difference from an intact wrist (type 1 > type 2) and in the direction of displacement (type 1 the bones moved in different directions while type 2 wrists moved as one block).

Conclusion This study suggests that midcarpal joint structure affects force transfer through the wrist and may predict wrist behavior following excision of the distal pole of the scaphoid. Specifically, type 1 wrists may be more prone to midcarpal joint collapse after excision.

Level of evidence: 1.

Keywords

instability - lunate type - midcarpal joint - scaphoid - scaphoidectomy - wrist

Publication History

Received: 02 January 2024

Accepted: 22 February 2024

Article published online:
14 March 2024

• References

• 1 Garcia-Elias M, Lluch A. Partial excision of scaphoid: is it ever indicated?. Hand Clin 2001; 17 (04) 687-695x
• 2 Corbin C, Warwick D. Midcarpal instability after excision arthroplasty for scapho-trapezial-trapezoid (STT) arthritis. J Hand Surg Eur Vol 2009; 34 (04) 537-538
• 3 Malerich MM, Catalano III LW, Weidner ZD, Vance MC, Eden CM, Eaton RG. Distal scaphoid resection for degenerative arthritis secondary to scaphoid nonunion: a 20-year experience. J Hand Surg Am 2014; 39 (09) 1669-1676
• 4 Malerich MM, Clifford J, Eaton B, Eaton R, Littler JW. Distal scaphoid resection arthroplasty for the treatment of degenerative arthritis secondary to scaphoid nonunion. J Hand Surg Am 1999; 24 (06) 1196-1205
• 5 McCombe D, Ireland DC, McNab I. Distal scaphoid excision after radioscaphoid arthrodesis. J Hand Surg Am 2001; 26 (05) 877-882
• 6 Viegas SF. Limited arthrodesis for scaphoid nonunion. J Hand Surg Am 1994; 19 (01) 127-133
• 7 Garcia-Elias M, Lluch A, Saffar P. Distal scaphoid excision in scaphoid-trapezium-trapezoid arthritis. Tech Hand Up Extrem Surg 1999; 3 (03) 169-173
• 8 Catalano III LW, Ryan DJ, Barron OA, Glickel SZ. Surgical management of scaphotrapeziotrapezoid arthritis. J Am Acad Orthop Surg 2020; 28 (06) 221-228
• 9 Pendola M, Petchprapa C, Wollstein R. A preliminary model of the wrist midcarpal joint. J Wrist Surg 2021; 10 (06) 523-527
• 10 Wollstein R, Kramer A, Friedlander S, Werner F. Midcarpal structure effect on force distribution through the radiocarpal joint. J Wrist Surg 2019; 8 (06) 477-481
• 11 Viegas SF. The lunatohamate articulation of the midcarpal joint. Arthroscopy 1990; 6 (01) 5-10
• 12 Viegas SF, Patterson RM, Hokanson JA, Davis J. Wrist anatomy: incidence, distribution, and correlation of anatomic variations, tears, and arthrosis. J Hand Surg Am 1993; 18 (03) 463-475
• 13 Marques R, Melchor J, Sanchez-Montesinos I, Roda O, Rus G, Hernandez-Cortes P. Biomechanical finite element method model of the proximal carpal row and experimental validation. Front Physiol 2021; 12: 749372
• 14 Spatz HC, O'Leary EJ, Vincent JF. Young's moduli and shear moduli in cortical bone. Proc Biol Sci 1996; 263 (1368): 287-294
• 15 Rhee PC, Moran SL, Shin AY. Association between lunate morphology and carpal collapse in cases of scapholunate dissociation. J Hand Surg Am 2009; 34 (09) 1633-1639
• 16 Rhee PC, Moran SL. The effect of lunate morphology in carpal disorders: review of the literature. Curr Rheumatol Rev 2020; 16 (03) 184-188
• 17 Nguyen AP, Herman B, Mahaudens P, Everard G, Libert T, Detrembleur C. Effect of age and body size on the wrist's viscoelasticity in healthy participants from 3 to 90 years old and reliability assessment. Front Sports Act Living 2020; 2: 23