, Volume 5, Issue 2, pp 143-148

Varus Gonarthrosis Predisposes to Varus Malalignment in TKA

Purchase on Springer.com

$39.95 / €34.95 / £29.95*

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip–knee–ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >±3° from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4° compared with 1.0° of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.

Level of Evidence: Level IV: Retrospective Case Series
Richard Laskin, MD worked for Smith & Nephew as a consultant. Thomas Heyse, MD and Ralf Decking, MD received scientific funding from Smith & Nephew.
Each author certifies that his or her institution has approved the reporting of these cases and that all investigations were conducted in conformity with ethical principles of research.