Predicting clinical outcomes after total knee arthroplasty from preoperative radiographic factors of the knee osteoarthritis

Abstract

Background: Total knee arthroplasty (TKA) is the major surgical treatment for end-stage osteoarthritis (OA). Despite its effectiveness, there are about 20% of patients who are dissatisfied with the outcome. Predicting the surgical outcome preoperatively could be beneficial in order to guide clinical decisions. Methods: One-hundred and ten knees of 110 consecutive patients who underwent TKAs for varus knees resulting from OA were included in this study. Preoperative varus deformities were evaluated by femorotibial angle (FTA), medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA), and classified as a severe varus (SV) or a mild varus (MV) group. The osteophyte score (OS), which we developed originally, was also calculated based on the size of the osteophytes and classified as groups with more or less osteophytes. We compared preoperative and 1year postoperative range of motion, the Knee Society Score, and Japanese Knee injury Osteoarthritis Outcome Score (KOOS) between SV and MV groups (varus defined by FTA, MPTA, or LDFA), in each group with more or less osteophytes. Results: When varus deformities were defined by FTA, regardless of OS, postoperative KOOS subscales and/or the improvement rates were significantly higher in the SV group than in the MV group. When varus defined by MPTA, regardless of OS, there were no significant differences in postoperative KOOS subscales between groups. However, when varus defined by LDFA, scores for pain, activities of daily living (ADL), and quality of life (QOL) on postoperative KOOS and/or the improvement rates were significantly higher in the SV group than in the MV group only in patients with less osteophytes. No significant differences were found between groups in patients with more osteophytes. Conclusions: We classified OA types by radiographic measurements of femur and tibia in combination with OS. Postoperative patient-reported outcomes were better in patients with SV knees but were poor in patients with knees with MV deformity and less osteophytes.

The impact of postoperative inclination of the joint line on clinical outcomes in total knee arthroplasty using a prosthesis with anatomical geometry

“…These observations show physiological inclination of the joint line in normal knees and its racial or gender differences. Regarding the joint line inclination in OA knees, we have shown that the mean medial proximal tibial angle (MPTA) for elderly Japanese patients was 83.9° 37 , which corresponds to 6.1 degrees of inclination in the present study.…”

Seven phenotypes of varus osteoarthritic knees can be identified in the coronal plane

“…Preoperative application of this classification may facilitate decision‐making in terms of bony location (distal femur vs proximal tibia) and type of corrective osteotomy (closed vs open), as well as optimal resection angles, modification of or special techniques that may be required for knee arthroplasty. A recent report suggests that severity of varus may impact results [32]. It seems reasonable to speculate that, for example, type 1 knees requiring standardized resections and little or no soft tissue releases may differ substantially in outcomes and satisfaction from, say, type 3 knees requiring an extraarticular corrective osteotomy or a constrained implant.…”

Medial Opening Wedge Proximal Tibial Osteotomy: Lessons Learned from a Series of 175 Consecutive Cases

“…However, pain and symptoms subsections are a little lower in our study, by an average of about 10 points each, than what is found in the literature following TKA. 35,36 Matsumoto et al . 35 described the same differences of the KOOS score when comparing HTO and TKA outcomes.…”