Severe and morbid obesity (BMI ≥ 35 kg/m2) does not increase surgical time and length of hospital stay in total knee arthroplasty surgery

Purpose

Certain aspects of total knee arthroplasty (TKA) in severely and morbidly obese (SMO) patients (BMI ≥ 35 kg/m²) remain controversial. This study aimed to assess the duration of TKA surgery and hospital stay in relation to patients’ BMI.

Methods

Three operative times during TKA surgery were recorded: tourniquet time, to determine surgical difficulty, total surgical time, to assess the difficulty of achieving anaesthesia, and time in the surgical area, to assess patient management in the surgical area. Length of hospital stay was also calculated. Data were collected prospectively from consecutive patients and were recorded in a database for retrospective analysis.

Results

Data were obtained from 922 consecutive patients undergoing TKA. The non-obese group comprised 418 patients (45.3 %), obese group Class I 331 (36 %), and the SMO group (Class II–III) 173 (18.7 %). Mean tourniquet time was 53 min, mean total surgical time was 84 min, and mean time in the surgical area was 132 min. There were no differences according to BMI group. Median length hospital stay (LHS) was 6 days in all patients regardless of BMI. Factors that significantly prolonged LHS were ASA III–IV and pre-operative haemoglobin between 12 and 13 g/dl.

Conclusion

Severely and morbidly obese (SMO) patients (BMI ≥ 35 kg/m²) undergoing TKA surgery do not require longer operative time or hospital stay than non-obese or obese Class I patients. The fact that surgical time was not significantly different could be due to greater specialisation in the treatment of these patients, which may favour a lower incidence of post-operative complications.

Level of evidence

Retrospective comparative study, Level IV.