Spontaneous popliteal vascular injury in the morbidly obese

Purpose: Morbidly obese patients who sustained popliteal vascular injury after spontaneous knee dislocation (KD) were studied. Methods: Seven morbidly obese patients (body mass index [BMI] >35 kg/m² and >100 lb over ideal body weight) who sustained spontaneous KD while upright were reviewed. Results: Severe popliteal arterial injury accompanied all spontaneous KD. The mean age of patients was 34.1 ± 6.7 years; the mean weight was 354 ± 150 lb (range, 220-702 lb); and mean BMI was 55 ± 21 kg/m² (range, 37-98.4). All had arterial avulsion and thrombosis. Three had concomitant venous injury. All underwent operative repair. Morbid obesity presented unique challenges to surgical management. Limited positioning, specialized operative tables, large incisions, deep exposure, special retraction, long operative times (mean, 537 ± 134 minutes), and major blood loss (mean, 2.5 ± 3 L) were standard. Five arterial injuries were repaired with interposition vein grafts, and 2 required tibial bypass. Venous repairs included thrombectomy and primary repair (n = 2) and interposition grafting (n = 1). Many complications were related to morbid obesity, including deep wound infection (n = 3), diabetic ketoacidosis (n = 2), and cor pulmonale from sleep apnea (n = 1). Despite patent grafts in all patients, 2 above-knee amputations were required for extensive neuromuscular loss. Conclusion: Morbid obesity is a specific risk factor for spontaneous KD and vascular injury. In addition, morbid obesity presents unique challenges to operative repair and predisposes patients to unusual major postoperative complications.