Abstract
Patients who have undergone Total Knee Replacement (TKR) improve their knee functions with time dependent recovery. However, the speed and degree of recovery widely varies from person to person. Practitioners generally find that postoperative satisfaction after TKR is closely related to the degree of preoperative severity in deformity. We focused on preoperative FTA to determine how the degree of deformity affects postoperative improvements after TKR.
Methods:
44 consecutive knees of 44 patients with medial osteoarthritis underwent TKR for nomination in this study. All operations were conducted by a single surgeon using a mid vastus approach with cemented posterior stabilized (PS) implant and patellar resurfacing. Patients were targeted for full weight bearing the next day.
Patients were divided into 3 groups of preoperative FTA: 174–180 degrees (11 knees), 181–189 degrees (17 knees), and more than 190 degrees (16 knees). Walking ability was assessed by gait speed and width of step. Balance was measured by a “Functional Reach Test (FR),” which is the difference between arm's length and maximal forward reach (Duncan PW et al. 1990), a “Timed Up and Go Test (TUG),” the time interval for a patient rise from an arm chair, walk 3 meters, and return (Podsiadlo and Richardson 1991), and the capacity to stand on one leg (one leg standing time trial). Every measurement was performed prior to the operation (pre-op), and 4 weeks after operation (post-op 4w). The recovery rate (%) was defined as post-op 4w/pre-op ×100. Data were analyzed by one-way ANOVA, and then differences among means were analyzed using Bonferroni procedures. P-values lower than 5% are regarded as significant.
Result:
The recovery rate of walking speed and TUG showed significant improvement in the FTA more than >190 degree group than that of 174–180 degree group. Every other result showed a higher recovery rate for the >190 degree group, although results were not statistically significant.
Discussion:
Both walking speed and TUG represent the patients' ability for walking and dynamic balancing, while FR and one leg standing depend more on the ability for static balancing. This study demonstrates that patients with severely deformed knees could show better postoperative recovery in walking and dynamic balancing than those with less severely deformed knees. Moreover, this study could suggest it is always not too late for patients with severely deformed knees to undergo TKR.
