High body mass index is not a contraindication for an arthroscopic ligament repair with biological augmentation in case of chronic ankle instability

Purpose Obesity remains frequently mentioned as a contraindication for lateral ankle ligament repair. The aim of the study was to compare the clinical results of an arthroscopic lateral ligament repair with biological augmentation between patients with a body mass index (BMI) of more than 30 and less than 30. Methods Sixty-nine patients with an isolated lateral ankle instability were treated with an arthroscopic anterior talofibular ligament (ATFL) repair with biological augmentation using the inferior extensor retinaculum (IER). Patients were divided into two groups according to their BMI: ≥ 30 (Group A; n = 26) and < 30 (Group B; n = 43). Patients were pre-and post-operatively evaluated, with a minimum of 2 years follow-up, and using the Karlsson Score. Characteristics of the patients, complications, ankle instability symptoms recurrence, and satisfaction score were recorded. Results In group A, the median Karlsson Score increased from 43.5 (Range 22–72) to 85 (Range 37–100) at follow-up. Complications were observed in seven patients (27%). Nineteen patients (73%) reported that they were “very satisfied”. One patient (4%) described persistent ankle instability symptoms. In group B, the median Karlsson Score increased from 65 (Range 42–80) to 95 (Range 50–100) at follow-up. Complications were observed in four patients (9%). Thirty-three patients (77%) reported that they were “very satisfied”. Two patients (5%) described persistent ankle instability symptoms. Pre-operative and at last follow-up Karlsson Score, results were significantly different between the two groups. There was no significant statistical difference in favour of satisfaction score, complications and recurrence of ankle instability between the two groups. Conclusion ATFL repair with biological augmentation using IER gives excellent results for patients with BMI ≥ 30. Compared to patients with BMI < 30, they present a slightly lower preoperative and postoperative Karlsson score, however, with a similar satisfaction rate, but are at higher risk of transient superficial peroneal nerve dysesthesia. Level of evidence Level III.