Isokinetic knee muscle strength comparison after enhanced recovery after surgery (ERAS) versus conventional setup in total knee arthroplasty (TKA): a single blinded prospective randomized study

Purpose Total knee arthroplasty (TKA) combined with the concept of enhanced recovery is of continued worldwide interest, as it is reported to improve early functional outcome and treatment quality without increasing complications. The aim of the study was to investigate isokinetic knee muscle strength after cemented TKA in combination with an enhanced recovery after surgery (ERAS) compared to a conventional setup. Methods In the single blinded prospective randomized study, 52 patients underwent navigated primary cemented TKA within an ERAS (n = 30) or a conventional setup (n = 22). Preoperatively, five days and four weeks after surgery isokinetic knee muscle strength with BIODEX-type measuring device (peak torque in Nm, work in Joules and power in Watt) and subjective patient-related outcome measures (PROMs) were investigated. Results The ERAS group showed significantly better outcomes in knee flexion at 180°/s (peak torque (Nm) p = 0.047, work (J) p = 0.040 and power (W) p = 0.016) 5 days postoperatively. The isokinetic measuring at knee extension 60°/s and 180°/s demonstrated no significant difference. The PROMs showed that patients were satisfied with the postoperative results in both groups. After 4 weeks, there was no longer a significant difference in isokinetic measuring at knee extension and flexion between the ERAS and conventional group. Conclusions TKA with the concept of ERAS improves excellent isokinetic outcome and patient satisfaction. The isokinetic muscle strength measurement can help patients and surgeons to modify expectations and improve patient satisfaction