The authors conducted this study in order to determine the feasibility and effectiveness of an outpatient rehabilitation protocol that included movement symmetry biofeedback on functional and biomechanical outcomes after total knee arthroplasty (TKA). While TKA reduces pain and improves functional ability, many patients experience strength deficits and movement abnormalities in the operated limb, despite outpatient rehabilitation. These asymmetries add to the load on the non-operated limb and greater asymmetry is related to worse functional outcomes. Biomechanical and functional metrics were assessed 2-3 weeks prior to TKA, at discharge from outpatient physical therapy, and 6 months following TKA in 11 patients (9 males and 2 females, mean ± SD age 61.4 ± 5.8 years, and body mass index [BMI] 33.1 ± 5.4 kg/m2) who received 6-8 weeks of outpatient physical therapy that included specialized symmetry training. Six month outcomes were compared to an age-, BMI- and sex-matched control group (9 males and 2 females, age 61.8 ± 5y, BMI 34.3 ± 5.1) that did not receive specialized symmetry retraining. Nine of 11 patients they studied showed clinically significant improvements that exceeded the minimal detectable change for all performance-based functional tests compared to the initial pre-TKA physical therapy evaluation. Six months after TKA, when walking, patients who underwent symmetry retraining had greater knee extension during midstance and had mean sagittal knee moments that were more symmetrical, bi-phasic, and more representative of normal knee kinetics compared to patients who did not undergo symmetry training. No patients experienced adverse events as the result of the protocol.
They concluded that administering symmetry retraining in addition to post-operative protocols is clinically viable, safe, and may have additional benefits lacking in rehabilitation protocols that focus on range of motion, strength and return to independence.