Reliability of Metacarpal Subsidence Measurements after Thumb Carpometacarpal Joint Arthroplasty

Abstract

Background Thumb metacarpal subsidence after trapeziectomy can affect clinical function over time. Methods for measuring subsidence after trapeziectomy have been described, and they rely on an intact thumb metacarpal or proximal phalanx for measurement. The authors evaluated the reliability and reproducibility of measuring the trapezial space ratio, using previously described methods. In addition, the authors evaluated a new method that measures trapezial space on a posteroanterior (PA) hand/wrist radiograph that does not rely on an intact thumb metacarpal or proximal phalanx for measurement, which can often be altered by degenerative changes or in cases in which metacarpophalangeal arthrodesis is performed during carpometacarpal (CMC) joint arthroplasty to correct excessive hyperextension. The authors hypothesized that a new method of calculating trapezial space would have comparable reliability and reproducibility to previously proposed methods.

Methods Thirty-seven PA hand/wrist radiographs from patients who had trapeziectomy with ligament reconstruction and tendon interposition were evaluated. Trapezial space was measured using PACS (Picture Archiving and Communication System) digital tools as the distance perpendicular to the tangents of the scaphoid and first metacarpal joint surfaces. All X-rays were evaluated individually by five fellowship-trained hand surgeons, twice, 4 weeks apart. The reviewers calculated trapezial space ratios, using three different methods, two previously described and a novel one: (1) trapezial space relative to first metacarpal length (classic 1); (2) trapezial space relative to proximal phalanx length (classic 2); and (3) trapezial space relative to capitate height (novel). Inter- and intraobserver reliabilities were measured using intraclass correlation coefficients (ICC) and limits of agreement for each method.

Results The authors identified excellent agreement between the classic 1, classic 2, and novel methods with an ICC greater than 0.8, indicating excellent agreement. The average trapezial space ratios for the thumb proximal phalanx, thumb metacarpal, and capitate methods were measured as 0.19, 0.12, and 0.24, respectively. The upper and lower limits of the 95% confidence intervals for both the inter- and intraobserver agreements of the aforementioned trapezial space ratios were (0.17–0.26), (0.11–0.17), and (0.21–0.34) for the interobserver rates and (0.11–0.25), (0.06–0.16), and (0.12–0.33) for the intraobserver rates, respectively.

Conclusion Measuring trapezial space is an important diagnostic tool to assess postoperative changes in thumb length. The trapezial space indexed to the capitate height method (novel) provides a simple and similarly reliable method for calculating the trapezial space ratio on a PA radiograph of the hand/wrist when other measurement techniques are unavailable and when the thumb metacarpal or proximal phalanx is not intact. The authors found a high degree of reproducibility and inter- and intraobserver reliability as measured by the ICC and the 95% limits of agreement that compare with previous agreements in the literature.

Keywords

carpometacarpal joint - intraclass correlation coefficient - trapezial space ratio

• References

• 1 Barron OA, Glickel SZ, Eaton RG. Basal joint arthritis of the thumb. J Am Acad Orthop Surg 2000; 8 (05) 314-323
• 2 Shuler MS, Luria S, Trumble TE. Basal joint arthritis of the thumb. J Am Acad Orthop Surg 2008; 16 (07) 418-423
• 3 Lins RE, Gelberman RH, McKeown L, Katz JN, Kadiyala RK. Basal joint arthritis: trapeziectomy with ligament reconstruction and tendon interposition arthroplasty. J Hand Surg Am 1996; 21 (02) 202-209
• 4 Davis TR, Brady O, Dias JJ. Excision of the trapezium for osteoarthritis of the trapeziometacarpal joint: a study of the benefit of ligament reconstruction or tendon interposition. J Hand Surg Am 2004; 29 (06) 1069-1077
• 5 Burton RI, Pellegrini Jr VD. Surgical management of basal joint arthritis of the thumb. Part II. Ligament reconstruction with tendon interposition arthroplasty. J Hand Surg Am 1986; 11 (03) 324-332
• 6 Pellegrini Jr VD, Burton RI. Surgical management of basal joint arthritis of the thumb. Part I. Long-term results of silicone implant arthroplasty. J Hand Surg Am 1986; 11 (03) 309-324
• 7 Putnam MD, Rattay R, Wentorf F. Biomechanical test of three methods to treat thumb CMC arthritis. J Wrist Surg 2014; 3 (02) 107-113
• 8 Yang SS, Weiland AJ. First metacarpal subsidence during pinch after ligament reconstruction and tendon interposition basal joint arthroplasty of the thumb. J Hand Surg Am 1998; 23 (05) 879-883
• 9 Downing ND, Davis TR. Trapezial space height after trapeziectomy: mechanism of formation and benefits. J Hand Surg Am 2001; 26 (05) 862-868
• 10 Kadiyala RK, Gelberman RH, Kwon B. Radiographic assessment of the trapezial space before and after ligament reconstruction and tendon interposition arthroplasty. J Hand Surg [Br] 1996; 21 (02) 177-181
• 11 Poulter RJ, Davis TR. Management of hyperextension of the metacarpophalangeal joint in association with trapeziometacarpal joint osteoarthritis. J Hand Surg Eur Vol 2011; 36 (04) 280-284
• 12 Klinefelter R. Metacarpophalangeal hyperextension deformity associated with trapezial-metacarpal arthritis. J Hand Surg Am 2011; 36 (12) 2041-2042
• 13 Bhat M, Davis TR, Bannerjee A. Trapezial space height measurement after trapeziectomy: a comparison of the use of standard and stress radiographs. J Hand Surg Am 2003; 28 (03) 390-396
• 14 De Smet L, Sioen W, Spaepen D, van Ransbeeck H. Treatment of basal joint arthritis of the thumb: trapeziectomy with or without tendon interposition/ligament reconstruction. Hand Surg 2004; 9 (01) 5-9
• 15 Iyer KM. The results of excision of the trapezium. Hand 1981; 13 (03) 246-250
• 16 Varley GW, Calvey J, Hunter JB, Barton NJ, Davis TR. Excision of the trapezium for osteoarthritis at the base of the thumb. J Bone Joint Surg Br 1994; 76 (06) 964-968
• 17 Murley AHG. Excision of the trapezium in osteoarthritis of the first carpometacarpal joint. J Bone Joint Surg 1960; 42B: 502-507