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Comparative Study
. 2025 Aug;46(8):887-894.
doi: 10.1177/10711007251341890. Epub 2025 Jun 26.

The Effect of Preoperative X/Y Ratio on Clinical Outcomes following Percutaneous Zadek Osteotomy for Insertional Achilles Tendinopathy

Sarah Hall Kiriluk  1 , Anne Holly Johnson  2 , Jonathan R M Kaplan  3 , Ettore Vulcano  4 , Thomas Lewis  5 , Peter Lam  6 , Oliver Schipper  7 , J Benjamin Jackson 3rd  1   8 , Tyler A Gonzalez  1   8
Affiliations
Comparative Study

The Effect of Preoperative X/Y Ratio on Clinical Outcomes following Percutaneous Zadek Osteotomy for Insertional Achilles Tendinopathy

Sarah Hall Kiriluk et al. Foot Ankle Int. 2025 Aug.

Abstract

Background: The percutaneous dorsal closing wedge calcaneal Zadek osteotomy (ZO) is an effective treatment for patients with insertional Achilles tendinopathy (IAT), although consensus is lacking on ideal patient selection. Tourné et al proposed that a preoperative calcaneal X/Y ratio <2.5 defines surgical candidacy, but this criterion remains controversial. This study evaluated whether patients with IAT benefit from percutaneous ZO regardless of preoperative X/Y ratio.

Methods: A retrospective comparative study of 27 patients undergoing percutaneous ZO was performed. Patients were stratified into 2 cohorts based on preoperative X/Y ratio (<2.5 vs ≥2.5). Primary outcomes were PROMIS scores for pain, function, and mobility at 3, 6, and 12 months. Secondary outcomes included complication rates and radiographic parameters. Minimal clinically important differences were used to assess clinical significance.

Results: Between May 2022 and May 2024, 27 cases were included in the current analyses. Seventeen cases had an X/Y <2.5; 10 had an X/Y ≥2.5. Both cohorts demonstrated significant improvement in PROMIS pain, function, mobility scores (P < .05). Patients with X/Y ≥2.5 demonstrated statistically greater improvement in pain scores than patients with X/Y <2.5 (P = .049) at 1-year follow-up. Ninety-eight percent of patients were satisfied following ZO intervention.

Conclusion: Percutaneous ZO demonstrated meaningful improvement in patients' function, pain, and mobility regardless of preoperative X/Y ratio. These findings challenge the use of the <2.5 X/Y threshold as a strict selection criterion. Percutaneous ZO may be a viable option for a broader population of IAT patients than previously considered.

Keywords: Achilles insertional tendinosis; Haglund deformity; Zadek osteotomy; insertional Achilles tendinopathy; minimally invasive surgery; percutaneous Zadek osteotomy; percutaneous osteotomy.

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Conflict of interest statement

Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Anne Holly Johnson, MD, reports disclosures relevant to article from royalties: Novastep, Treace Medical Concepts; stock: Carbon22, Altior Traima, BICMD. Jonathan R. M. Kaplan, MD, reports disclosures relevant to article as consultant for Artelon, Edge Surgical, Enovis / Novastep, Exactech, Surgical Fusion Technologies, Treace Medical Concepts, Vilex, Surgebright; royalties: Surgical Fusion Technologies, Treace Medical Concepts, Vilex. Ettore Vulcano, MD, reports disclosures relevant to article as consultant for Novastep, Treace, Vilex, Surgebright; royalties: Surgical Fusion Technologies, Treace Medical Concepts, Vilex. Thomas Lewis, MBChB(Hons), BSc(Hons), MRCS, MFSTEd, reports disclosures relevant to article of royalties and consulting from Vilex beyond the scope of this study and general disclosures from PhD tuition fees supported by MIFAS. Peter Lam, MBBS(Hons), FRACS, reports disclosures relevant to article as consultant for Enovis. Oliver Schipper, MD, reports disclosures relevant to article as consultant for Treace Medical Concepts Inc, SFI, Enovis, Exactech; royalties: Treace Medical Concepts Inc, SFI, Enovis. J. Benjamin Jackson III, MD, MBA, reports disclosures relevant to article as consultant for Synthes. Tyler A. Gonzalez, MD, MBA, reports disclosures relevant to article as consultant for Treace Medical Concepts Inc, Surgical Fusion Technologies, Stryker, Enovis, Exactech, Surgebright; royalties: Surgical Fusion Technologies, Treace Medical Concepts, Vilex. Disclosure forms for all authors are available online.

Figures

Graphical Abstract
Graphical Abstract
This is a visual representation of the abstract.
Figure 1.
Figure 1.
(A) X/Y ratio as described by Tourné et al,: X = total calcaneus length; Y = total greater tuberosity length. X represents the length from the posterior-most aspect of the calcaneus to the anterior-most aspect of the anterior process; Y represents the length from the posterosuperior prominence to the posterior-most aspect of the posterior subtalar joint facet. Measurements were taken on lateral, weightbearing radiographs, from preoperative (pre-ZO) and final (post-ZO) follow-up. (B) Calcaneal pitch angle in patient before (pre-ZO) and after (post-ZO) intervention with percutaneous Zadek osteotomy. All radiographs were weightbearing.
Figure 2.
Figure 2.
PROMIS (A) function, (B) pain, and (C) mobility scores at 3, 6, and 12 months following intervention with percutaneous Zadek osteotomy. Data are separated by cohort. Patients who had a preoperative X/Y <2.5 are represented in blue; patients who had a preoperative X/Y ≥2.5 are represented in red. *Statistically significant change (P < .05) from the respective preoperative PROMIS score on paired t test. [See online article for color figure.]
See this image and copyright information in PMC

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References

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