Prediction of post-operative range of motion using intra-operative soft tissue balance in total knee arthroplasty with navigation

Abstract

This study evaluated the influence of intra-operative soft tissue balance on post-operative range of motion in patients undergoing posterior-stabilized total knee arthroplasty with navigation. After implantation of all components in 31 consecutive patients, the joint component gap was measured manually with the knee at 0 , 90 , and 120 as guided by a navigation system. We designated soft tissue balance as the absolute difference between varus stress and valgus stress (medio-lateral laxity). Changes in medio-lateral laxity were calculated from 120 to 90 , 120 to 0 , and 90 to 0 . Correlations among post-operative flexion angles and pre-operative flexion angles, intra-operative flexion angle after implantation, soft tissue balance, and the changes were analyzed. The mean preand post-operative knee flexion angles were 114 ± 20 and 127 ± 9 , respectively. The mean intraoperative flexion angle was 137 ± 6. The post-operative flexion angle was positively correlated with the pre-operative flexion angle and intra-operative flexion angle after implantation. The change in soft tissue balance between 120 and 90 showed a positive correlation with the postoperative flexion angle. In conclusion, Assessment of intra-operative soft tissue balance could predict post-operative flexion angle. ARTICLE HISTORY

Patient-specific and intra-operatively modifiable factors assessed by computer navigation predict maximal knee flexion one year after TKA

“…In another study by Gatha et al [9], the only variable that was significantly correlated with the post-operative ROM was the preoperative ROM. The same was reported by et al [15]. The present results are in accordance with these findings.…”

High range of motion in the first ten postoperative days after TKA does not predict superior outcome in the long run

“…Other researchers investigated the effect of pre operative ROM instead early-postoperative ROM on long-term ROM outcome. The preoperative maximum knee flexion angle was found positively correlated with the flexion angles at 6 months [ 3 , 5 , 21 , 22 ] and 12 months [ 9 , 17 , 22 – 24 ]. Beside the influence of many other variables on the postoperative range of flexion, greater preoperative flexion angle was considered to have the most positive effect on the long-term flexion achieved after surgery and therefore the preoperative flexion was considered to be the primary determining variable of the long-term flexion outcome after TKA [ 22 , 24 ].…”

Factors Contributing to Patient Satisfaction and Expectations following Computer-Assisted Total Knee Arthroplasty

“…B. Braun; Aesculap, Tuttlingen, Germany) was used to ensure the accuracy of implantations and accurately measure the flexion angle of the knee during the joint component gap measurement with a tensor. 8 The study included 16 men (16 knees) and 93 women (114 knees), with a mean age of 73 years (range, 53-89 years) and a mean body mass index of 26.2 kg/m 2 (range, 17.3-44.3 kg/m 2 ). The diagnosis was osteoarthritis in all patients.…”

“…Intraoperative mediolateral laxity was defined as the difference between varus stress and valgus stress. 8 Various changes in mediolateral laxity were calculated, including from 0 to 30, 0 to 60, 0 to 90, 30 to 60, 60 to 90, and 90 to 120 degrees. Anatomic alignment was measured on the full leg-length standing radiograph, and ROM of the knee was measured.…”