Tibiofemoral subluxation in the coronal plane does not affect WOMAC and KOOS after total knee arthroplasty

Abstract

PurposeTo investigate the effect of preoperative coronal tibiofemoral subluxation (CTFS) on functional outcome, prosthesis type, insert thickness and revision rates in patients who underwent total knee arthroplasty (TKA). MethodsA total of 224 knees of 186 patients were included. Patients were divided into two groups as either with (Group 1, 114 knees of 86 patients) or without (Group 2, 124 knees of 100 patients) coronal lateral tibiofemoral subluxation. The mean follow‐up period was 71.3 ± 7.3 (range 60–84) months in group 1 and 69.4 ± 6.6 (range 61–79) months in group 2 (n.s.). Coronal tibiofemoral subluxation degree was measured in degrees on standing anteroposterior knee radiographs. Group 1 was divided into three subgroups according to amount of subluxation (< 5 mm, 6–10 mm and > 10 mm). Functional outcome was evaluated using the Western Ontario and McMaster Osteoarthritis Index (WOMAC) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at the last follow‐up visit. Prosthesis type, insert thickness and revision rates were compared between the two groups. ResultsThere were no significant differences between the two groups regarding patient demographics, prosthesis type, and revision rates (n.s.). The insert thickness was found significantly higher in group 1 (p < 0.001). The preoperative and postoperative WOMAC and KOOS scores were found no significantly different between the two groups (n.s.). Among subluxation (+) subgroups, there was no significant difference in functional outcome scores and revision rates (n.s.). However, prosthesis type and insert thickness were significantly associated with the amount of subluxation (p = 0.009 and p = 0.001, respectively). There was no significant correlation between the degree of lower extremity deformity and coronal tibiofemoral amount of subluxation (n.s.). ConclusionPreoperative CTFS does not adversely affect the WOMAC score, KOOS and revision rates after TKA. In the clinical practice, surgeons should be aware of the need for a posterior cruciate stabilizing prosthesis and a thicker insert in the presence of CTFS, especially with subluxation greater than 10 mm and to consider a spared bony resection on the tibia in patients suffering from CTFS. Level of evidenceIV.

Decision-making factors and their thresholds for total knee arthroplasty in lateral tibiofemoral osteoarthritis patients: a retrospective cohort study

“…In addition, TF subluxation, which refers to abnormal displacement of the femur with respect to the tibia, caused impingement of the tibial eminence on the femoral condyle [23]. By contrast, other previous studies have shown that preoperative coronal TF subluxation did not worsen functional outcomes [15] and was not an independent factor for TKA [24]. In the present study, only patients with lateral TF OA were included, and the degree of subluxation was investigated in both the lateral and central aspects of the knee joint.…”

“…To determine the knee joint radiographic parameters related to the lateral TF OA, we measured the hip–knee–ankle (HKA) angle from full-length standing views [ 14 ], the joint line convergence angle (JLCA), the TF subluxation measured in the lateral cortex [ 15 ], and the TF subluxation measured at the center (Fig. 2 ) [ 16 ].…”

Coronal tibiofemoral subluxation in patients with osteoarthritis was corrected after total knee arthroplasty

“…Although studies have evaluated the effect of CTFS on high tibial osteotomy and unicompartmental knee arthroplasty (UKA), [ 7 , 8 ] and the effect of CTFS on polyethylene thickness and knee pain after TKA, [ 9 ] there is no study to describe whether the existence of CTFS will affect the postoperative mechanical alignment and whether the TKA can correct CTFS.…”

“…[5] At the same time, some studies have confirmed that coronal tibiofemoral subluxation (CTFS) can lead to knee pain and poor knee function. [6] Although studies have evaluated the effect of CTFS on high tibial osteotomy and unicompartmental knee arthroplasty (UKA), [7,8] and the effect of CTFS on polyethylene thickness and knee pain after TKA, [9] there is no study to describe whether the existence of CTFS will affect the postoperative mechanical alignment and whether the TKA can correct CTFS. This is the first study to evaluate the effect of preoperative CTFS on postoperative mechanical alignment in patients with Li and Fu • Medicine (2022) Medicine…”