The risk of manipulation under anesthesia due to unsatisfactory knee flexion after fast-track total knee arthroplasty

- Reduced length of stay in fast-track TKA could theoretically compromise satisfactory ROM after surgery.
- The prevalence of manipulation is statistically significant lower with increasing knee flexion at discharge.
- A knee ROM of ≥ 70° of flexion and an extension deficit of ≤ 10° at discharge defines an optimal-zone with low risk of MUA.
- Fast-track TKA with reduced length of stay may be considered safe based on the acceptable manipulation rate after TKA.

BackgroundFast-track TKA has significantly shortened the time available for physiotherapists to optimize knee ROM before discharge. Safety aspects concerning knee stiffness and the need for manipulation in a fast-track setting need to be illuminated. The study aims were to analyze if fast-track TKA can be considered safe considering rates of knee manipulation and if there is an association between knee ROM at time of discharge and the need for later manipulation.MethodsPrimary TKAs operated in 2011 at our institution were eligible for inclusion. The study group consisted of 359 TKAs.ResultsManipulation of the knee was performed in 21 of 359 TKAs (5.8%). Seventy-one percent were discharged with a flexion ≥ 70° combined with an extension deficit of ≤ 10°. The occurrence of MUA for these patients was 4.3%. The prevalence of knee manipulation showed a statistically significant association with the achieved knee flexion at discharge (p = 0.02). Median length of stay was two days.ConclusionCompared with literature findings fast-track TKA surgery may be considered safe based on the acceptable rate of knee manipulations after TKA (5.8%). We suggest ROM of ≥ 70° flexion combined with an extension deficit of ≤ 10° as an “optimal-zone” for ROM at discharge. The reason for this is the low occurrence of MUA (4.3%) in relation to the large amount of TKAs it represents (71%). The indication for MUA is multifactorial and ROM at discharge serves only as an indicator of later MUA risk.