Comment on “Long-Term Survival Rate and Outcomes for Amandys Implant: A 10-Year Minimum Follow-up of 84 Cases”

Dear Editor,

We read with great interest the study by Berry et al, which provides valuable long-term data on the Amandys pyrocarbon wrist implant, a device positioned as an alternative to total wrist arthroplasty (TWA) and total wrist fusion (TWF) in managing advanced wrist destruction.[1] The reported 10-year survival rate of 86.4% and high patient satisfaction reinforce the potential durability of interposition arthroplasty. However, several methodological and conceptual concerns warrant discussion.

First, the survival analysis defines surgical revision as the sole endpoint, without stratifying major versus minor revisions. Notably, 9 of the 10 revisions were due to instability within the first 15 months, and only 1 involved ulnocarpal conflict. The absence of conversions to TWA or TWF is cited to imply stable implant performance, yet this endpoint overlooks the clinical burden of repeated repositioning and the learning curve effect, which may not be generalizable to lower-volume centers or early-career surgeons.[2]

Second, the study reports no statistically significant differences in radiological indices over time. However, measures such as the McMurtry carpal height index and radial epiphyseal subsidence showed numerical declines. Without bone density stratification or a biomechanical analysis of implant–bone interactions, it remains unclear whether these radiological stabilities translate into biomechanical integrity,[3] particularly given the absence of osteointegration in pyrocarbon implants.[4]

Third, nearly 49% of the original cohort was lost to follow-up, with minimal information on mortality or baseline comparability. This raises concerns about survivor bias, particularly since long-term failures may remain undocumented among unreachable patients.[5]

In summary, while the Amandys implant demonstrates promise in preserving motion and function, its early revision rate, absence of bone integration, and attrition bias warrant caution before extrapolating these findings to broader clinical practice. Further multicenter, controlled studies are needed to validate its long-term utility against established reconstructive strategies.

Declaration of GenAI Use

Generative artificial intelligence tools, including Paperpal and ChatGPT-4o, were utilized solely for language, grammar, and stylistic refinement. These tools had no role in the conceptualization, data analysis, interpretation of results, or substantive content development of this manuscript. All intellectual contributions, data analysis, and scientific interpretations remain the sole work of the authors. The final content was critically reviewed and edited to ensure accuracy and originality. The authors take full responsibility for the accuracy, originality, and integrity of the work presented.

Authors' Contributions

R.M.: Writing—original draft, writing—review and editing. R.S.: Conceptualization, methodology, validation, supervision, project administration, writing—original draft, writing—review and editing.

Publication History

Received: 29 June 2025

Accepted: 10 September 2025

Article published online:
22 September 2025

• References

• 1 Berry C, Kerjean Y, Loubersac T, Gaisne E, Bellemère P. Long-term survival rate and outcomes for Amandys implant: a 10-year minimum follow-up of 84 cases. J Wrist Surg 2025;
• 2 Nugent M, Young SW, Frampton CM, Hooper GJ. The lifetime risk of revision following total hip arthroplasty. Bone Joint J 2021; 103-B [phone]
• 3 Gao X, Fraulob M, Haïat G. Biomechanical behaviours of the bone-implant interface: a review. J R Soc Interface 2019; 16 (156) 20190259
• 4 Schramm M, Maestro M, Decroocq L. Metatarsophalangeal HAPY spherical pyrocarbon implant: technical note. Orthop Traumatol Surg Res 2021; 107 (05) 102926
• 5 Patel S, Kumar V, Khan S, Salaria A. Loss to follow-up: a deceptive enigma. Ann Natl Acad Med Sci 2021; 57 (02) 120-122