The Effect of Joint Line Elevation on In Vivo Knee Kinematics in Bicruciate Retaining Total Knee Arthroplasty

Abstract

Prior studies have reported a negative effect on both clinical outcomes and patient-reported outcome measures (PROMS) following joint line elevation (JLE) in cruciate-retaining (CR) total knee arthroplasty (TKA) and posterior stabilized (PS) TKA designs. This experimental study was aimed to quantify the effect of JLE on in vivo knee kinematics in patients with bicruciate retaining (BCR) TKA during strenuous activities. Thirty unilateral BCR TKA patients were evaluated during single-leg deep lunge and sit-to-stand using a validated combined computer tomography and dual fluoroscopic imaging system. Correlation analysis was performed to quantify any correlations between JLE and in vivo kinematics, as well as PROMS. There was a significant negative correlation between JLE and maximum flexion angle during single-leg deep lunge (ρ = −0.34, p = 0.02), maximum varus joint angles during single-leg deep lunge (ρ = −0.37, p = 0.04), and sit-to-stand (ρ = −0.29, p = 0.05). There was a significant negative correlation between JLE and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (ρ = −0.39, p = 0.01) and knee disability and osteoarthritis outcome score physical function (KOOS-PS; ρ = −0.33, p = 0.03). The JLE that yields a significant loss in PROMS and maximum flexion angles were 2.6 and 2.3 mm, respectively. There was a linear negative correlation of JLE with both in vivo knee kinematics and PROMS, with changes in JLE of greater than 2.6 and 2.3 mm, leading to a clinically significant loss in PROMS and maximum flexion angles, respectively, suggesting an increased need to improve surgical precision to optimize patient outcomes following BCR TKA.

The Effect of Tibiotalar Joint Line Level Alterations on Tibiotalar Range of Motion Following Total Ankle Arthroplasty

“…Although the apparent overall joint line changes are small, this is consistent with knee arthroplasty literature noting knee joint line elevation as small as 2.6 and 2.3 mm resulting in a clinically significant loss in PROMs and maximum flexion angles, respectively. 25 This suggests an increased need to improve surgical precision to optimize patient outcomes following TAA.…”

“…Although not yet studied in the ankle, femoral joint line restoration has been identified as a major determinant of postoperative ROM following total knee arthroplasty with elevation of the joint line resulting in patella baja and decreased ROM. 3,18,34 A recent study by Klemt et al 25 reported a linear negative correlation between joint line elevation in both in vivo knee kinematics and PROMs. Specifically, knee joint line elevation of greater than 2.6 and 2.3 mm resulted in a clinically significant loss in PROMs and maximum flexion angles, respectively.…”

“…A critical threshold of anywhere from 2 to 8 mm, most commonly 4-5 mm, of joint alteration has been described for maintenance of optimal outcomes. 7,8,13,25,30,31,36 In regard to the TTJL and ankle arthroplasty, Harnroongroj et al 19 described the first method for measuring the TTJL before and after TAA termed "joint line height ratio." The authors reported excellent inter-and intrarater reliability of their radiographic measurements (r > 0.9).…”

“…A critical threshold of anywhere from 2 to 8 mm, most commonly 4-5 mm, of joint alteration has been described for maintenance of optimal outcomes. 7,8,13,25,30,31,36…”

Evaluation of the flexion gap with a distal femoral trial component in posterior-stabilized total knee arthroplasty

“…Joint line changes after TKA have an influence on range of motion (ROM), patella height, and mid-flexion laxity [7][8][9], and thereby TKA has generally been performed by cutting the distal femur, under consideration of the implant thickness, without changing the joint line and patella height. Bone gap was measured after conventional cutting of distal femur and proximal tibia, revealing an increase in flexion gap as compared with that after setting the implant.…”