The Knee, ISSN: 1873-5800, Vol: 24, Issue: 6, Page: 1462-1468

Preoperative knee deformity and kinematics impact postoperative knee kinematics in total knee arthroplasty

Seito, Naoki; Onodera, Tomohiro; Kasahara, Yasuhiko; Kondo, Eiji; Iwasaki, Norimasa; Majima, Tokifumi
Knee

Background

The purpose of this study was to evaluate the relationship between the preoperative knee deformity/kinematic pattern and the postoperative knee kinematic pattern in posterior cruciate ligament substituting (PS)-total knee arthroplasty (TKA).

Methods

This study involved 39 patients with medial osteoarthritis who underwent a primary PS-TKA using a computed-tomography-based navigation system. All the operations were performed by a single surgeon using a subvastus approach, modified gap technique and the same PS type of prosthesis (Genesis II™ total knee system, Smith & Nephew, Memphis, TN, USA). Knee deformity, kinematic pattern after capsule incision (preoperative knee kinematics), and kinematic pattern after implantation (postoperative knee kinematics) in PS-TKA were measured. Kinematic patterns were divided into two groups: a medial pivot group and a non-medial pivot group.

Results

Preoperative varus knee deformity was significantly larger in the non-medial pivot group than in the medial pivot group (femorotibial angle: 184.7 ± 6.4° vs. 180.8 ± 3.9°, P < 0.05). In addition, preoperative knee kinematics were conserved postoperatively, at a rate of 82% (P < 0.01).

Conclusions

The severity of varus knee deformity and the preoperative knee kinematic pattern might have affected the postoperative knee kinematics in PS-TKA. This must be confirmed with a randomized controlled trial on a large population study. Level of evidence: case control study, Level III.


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