Dose Severity of Achilles Tendinopathy on Preoperative MRI Predict Functional Outcomes after Minimally Invasive Zadek Osteotomy?
Authors: Hall Sarah , Kaplan Jonathan , Schipper Oliver , Johnson A. Holly , Vulcano Ettore , Jackson J. Benjamin , Gonzalez Tyler 
Published: December 2024

Category: Hindfoot; Ankle Introduction/Purpose: Minimally Invasive Zadek osteotomy (MIS ZO) has been demonstrated to be a safe and effective surgical intervention for patients with Insertional Achilles Tendinopathy (IAT) and Haglund’s deformity. However, there is limited literature to guide surgeons one which patients may be the best candidates for MIS ZO. Severity of IAT on preoperative MRI may correlate with post operative functional outcomes and help guide patient selection for treatment with MIS ZO. The current study evaluated the postoperative outcomes of MIS ZO in patients with various grades of Achilles tendinopathy on preoperative MRI, to determine if severity of disease on preoperative MRI could be predictive of improved functional outcomes after MIS ZO. Methods: Patients who underwent MIS ZO for IAT and Haglund’s deformity were identified and retrospectively analyzed at a mean of 15.59 months follow-up. Achilles pathology was graded as previously described by Nicholson et al. on preoperative MRI. Grade 1 describes anteroposterior diameter of 6-8 mm and nonuniform degeneration; grade 2 describes diameter >8 mm and < 50% uniform tendon degeneration; grade 3 describes tendon diameter >8 mm and uniform degeneration of >50% tendon width. Fourteen patients met our inclusion criteria. Four patients exhibited grade 1 pathology preoperatively, 3 patients exhibited grade 2 pathology preoperatively, and 7 patients exhibited grade 3 pathology preoperatively. Preoperative and postoperative Patient Reported Outcome Measurement Information System (PROMIS) scores, complications, and revisions were recorded for each patient. PROMIS scores were compared using a paired t-test. All other continuous data was compared by Analysis of Variance (ANOVA); all categorical data was compared using Chi-squared analysis. P< 0.05 were considered significant. Results: PROMIS pain score improved postoperatively in patients with grade 1 66.75±5.50 to 59.00±7.75, p=0.036) and grade 3 (69.86±6.17 to 55.71±10.44, p=0.011) Achilles tendinopathy on preoperative MRI. Meanwhile, in patients with grade 2 pathology, PROMIS physical function (38.33±8.50 to 43.67±9.07, p=0.02) improved postoperatively. In the grade three group, 1/7 (14.29%) patients experienced transient neuritis that resolved at 3 months without further treatment and 1/7 (14.29%) patients required revision surgery to an open midline splitting Haglund’s resection. Meanwhile no patients in either the grade one or grade two groups required reoperation, rehospitalization, or complications. 13/14 (93%) patients were very satisfied with their procedure and wound undergo it again. Conclusion: These early data suggest that patients with IAT, regardless of severity, improve after MIS ZO. Therefore, ZO may be a reasonable first line option for all patients presenting with IAT. In our small retrospective study, we were able to demonstrate significant improvement in pain and/or function following ZO in all grades of IAT tendinous pathology on preoperative MRI. This study may help guide surgeons when deciding between MIS ZO and other surgical options for IAT and Haglund’s deformity. Further, large prospective studies are warranted to further investigate outcomes and indications of MIS ZO in patients with IAT and Haglund’s deformity