Minimally invasive unicompartmental knee replacement with a nonimage-based navigation system

Abstract

In a prospective study, two groups of 20 unicompartmental knee replacements (UKR) each were operated either using a CT-free navigation system or the conventional minimal invasive technique. Radiographic assessment of postoperative alignment was performed by long-leg coronal and lateral radiographs. The results revealed a significant difference between the two groups in favor of navigation. In the computer-assisted group, 95% of UKRs were in a range of 4-0 varus (mechanical axis) compared with 70% in the conventional group. The only inconvenience was a prolonged operation time (+19 min). Due to the limited exposure, the navigation system is helpful in achieving a more precise component orientation. The danger of overcorrection is diminished by real-time information about the leg axis at each step during the operation.RØsumØ Dans une Øtude prospective, deux groupes de 20 proth ses unicompartimentales de genou ont ØtØ opØrØs soit en utilisant un syst me de navigation sans scanner, soit par une technique mini-invasive habituelle. L'estimation de l'alignement postopØratoire a ØtØ faite avec des grandes radiographies frontales et sagittales coronales. Les rØsultats ont rØvØlØ une diffØrence notable entre les deux groupes en faveur de la navigation. Dans le groupe aidØ par ordinateur, 95% des cas Øtaient dans une gamme de 0 à 4 de varus comparØ à 70% dans le groupe conventionnel. Le seul inconvØnient Øtait un temps d'opØration prolongØ (+19 min). En raison de l'exposition limitØe, le syst me de navigation est utile pour donner une orientation plus prØcise aux implants. Le danger d'hypercorrection est diminuØ par l'information en temps rØel sur l'axe du membre à chaque temps de l'opØration. IntroductionIn several studies, excellent 10-year survivorships of unicompartmental knee replacement (UKR) have been reported [3,4,6]. A major advantage of UKR is that it can be performed through a small incision that need not be extended into the quadriceps tendon [1,16]. Despite the favor of preserving undamaged soft tissue, the surgeon has a reduced overview and is in risk of component malpositioning [8].Recently, navigation systems have been developed to improve the accuracy of component alignment in total knee arthroplasty (TKA), and the first follow-up results of computer-assisted TKA are promising [10,15]. To our knowledge, for computer-assisted UKR, only one study is available in the literature. Jenny et al. [12] reported superior results when using a navigation system in UKR compared with the standard procedure. There are only a few previous papers focussing on postoperative alignment after conventional UKR [11], especially when using a minimally invasive technique [8]. Fisher et al. reported significant differences of the postoperative leg alignment when comparing the results of minimally invasive versus open UKR [8].The aim of this prospective study was to analyze the accuracy of postoperative leg alignment and component orientation in minimally invasive, computer-assisted UKR when using a nonimage-based navigatio...

Navigation of the tibial plateau alone appears to be sufficient in computer-assisted unicompartmental knee arthroplasty

“…Navigation has been used to improve the reproducibility of the surgical technique, and it has been extensively demonstrated to be efficient [14,16]. Since then, several studies have confirmed the effectiveness of navigation improving UKA implantation [15,17,22], whereas one article did not show any improvement [23].…”

“…Computerassisted navigation systems have since been used in the positioning of UKA and the initial results were very encouraging [12][13][14][15][16][17][18]. UKA navigation can be done in two ways: either by navigating only the tibial cut while the femoral cuts are performed using conventional instrumentation based on the tibial cut or by navigating both the tibial and the femoral cuts.…”

Computer-assisted unicompartmental knee arthroplasty using dedicated software versus a conventional technique

“…However, a limitation of the original UKA studies was the use of a software application intended for TKA navigation. Subsequently, Perlick et al, in 2004, reported that in navigated UKA, the danger of overcorrection is diminished by real-time information about the leg axis at each step during the operation [16].…”

“…However, despite improved component alignment in TKA using navigation, no clear clinical advantages are demonstrated [11,12]. More obvious clinical advantages may be expected in a more demanding surgery, such as the UKA, where traditional techniques can lead to poor alignment accuracy [13][14][15][16]. In fact, results of a recent meta-analysis suggest that despite longer surgical time, the use of a navigation system in UKA results in more accurate component positioning compared with the conventional implantation method [17].…”

Navigated lateral unicompartmental knee arthroplasty — Technique and case report

“…Computer-assisted navigation has been shown to improve postoperative leg alignment compared to conventional techniques [11]. Navigation generally has been shown to increase the congruency of the planned-versus-achieved leg alignment in corrective lower-limb osteotomies and component positioning in TKA [12][13][14][15].…”