Efficacy of post-operative partial weight-bearing after total knee arthroplasty - a prospective observational trial.

PURPOSE: There is little evidence proving the concept of partial weight-bearing to be efficient and feasible. Using insole pressure measurement systems, this study aimed to explore the compliance to prescribed weight-bearing restrictions after total knee arthroplasty (TKA).

METHODS: 50 patients after TKA were recruited in a prospective manner. They were advised to limit weight-bearing of the affected limb to 200 N. True load was measured via insole force-sensors on day one after surgery (M1) and before discharge (M2). Compliance to the rehabilitation protocol was the primary outcome parameter.

RESULTS: At M1 and M2 compliance to the rehabilitation protocol was 0% und 2%, respectively. 84% (M1) and 90% (M2) of patients overloaded the affected limb during every step. The affected limb was loaded with 50% ± 14% (M1) and 57% ± 17% (M2) of body weight. Patients older than 65 loaded the affected limb on average 17% (M1) and 34% (M2) more than their younger counterparts did. This difference was even more pronounced when walking stairs up (49% increase on average) and down (53% increase on average).

CONCLUSION: Surgeons must take into consideration that the ability to maintain partial weight-bearing after TKA is highly dependent on the age of the patient and the achievable load reduction is determined by the patient's body weight.