The Contemporary "Ertl": A Functional Below-Knee Amputation for Nontraumatic Comorbid Populations.

Background: The osteomyoplastic (Ertl) approach to below-knee amputation (BKA) is an alternative to the "gold standard" Burgess technique. This study investigates Ertl's functional outcomes and perioperative considerations performed in a highly comorbid patient population.

Methods: Medical records of BKA (Ertl and non-Ertl) performed by a single surgeon between January 2017 and October 2021 were retrospectively reviewed.

Results: Our cohort comprised 294 BKAs performed via Ertl (n = 51/294, 17.3%) and non-Ertl (n = 243/294, 83%). Ertl patients were younger (50.1 vs 60.6 years, P < 0.001) and had fewer comorbidities (Charlson Comorbidity Index: 2.7 vs 5.5, P < 0.001). Ertl was associated with higher rates of targeted muscle reinnervation than non-Ertl (n = 48/51, 94.1% vs n = 162/239, 67.8%, P < 0.001). There were no significant differences in short-term complications (n = 52/294, 17.7%) or reoperation (n = 57/294, 19.4%) rates. Bony union was demonstrated at a median of 6.1 months without evidence of nonunion beyond 6 months postoperatively. Ertl conferred a shorter time to ambulation (2.3 vs 3.7 months, P < 0.001) and prosthesis use (2.5 vs 3.5 months, P = 0.008). By a median of 15.6 months, a greater percentage of Ertls were ambulatory (n = 46/51, 90.2% vs n = 162/232, 69.4%, P = 0.002). Postoperative pain was minimal without between-group differences. Mortality occurred less often in the Ertl versus non-Ertl group (Ertl n = 1/51, 2.0% vs non-Ertl 50/236, 20.6%, P = 0.001).

Conclusions: This study reinforces the current literature on Ertl's functional advantages in appropriate, carefully selected patients and extends our previous work demonstrating the utility in nontraumatic lower extremity amputation for multimorbid patients.