Functional outcome and alignment in computer-assisted and conventionally operated total knee replacements

Abstract

We performed a randomised controlled trial comparing computer-assisted surgery (CAS) with conventional surgery (CONV) in total knee replacement (TKR). Between 2009 and 2011 a total of 192 patients with a mean age of 68 years (55 to 85) with osteoarthritis or arthritic disease of the knee were recruited from four Norwegian hospitals. At three months follow-up, functional results were marginally better for the CAS group. Mean differences (MD) in favour of CAS were found for the Knee Society function score (MD: 5.9, 95% confidence interval (CI) 0.3 to 11.4, p = 0.039), the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales for 'pain' (MD: 7.7, 95% CI 1.7 to 13.6, p = 0.012), 'sports' (MD: 13.5, 95% CI 5.6 to 21.4, p = 0.001) and 'quality of life' (MD: 7.2, 95% CI 0.1 to 14.3, p = 0.046). At one-year follow-up, differences favouring CAS were found for KOOS 'sports' (MD: 11.0, 95% CI 3.0 to 19.0, p = 0.007) and KOOS 'symptoms' (MD: 6.7, 95% CI 0.5 to 13.0, p = 0.035). The use of CAS resulted in fewer outliers in frontal alignment (> 3° malalignment), both for the entire TKR (37.9% vs. 17.9%, p = 0.042) and for the tibial component separately (28.4% vs 6.3%, p = 0.002). Tibial slope was better achieved with CAS (58.9% vs. 26.3%, p < 0.001). Operation time was 20 minutes longer with CAS. In conclusion, functional results were, statistically, marginally in favour of CAS. Also, CAS was more predictable than CONV for mechanical alignment and positioning of the prosthesis. However, the long-term outcomes must be further investigated.

A randomized controlled trial to compare component placement in navigated total knee arthroplasty using original and streamlined registration processes

“…Our times were recorded from first-skin incision to completion of closure of the wound (skin-to-skin) to give a measure of the actual time the operation takes. The mean “skin-to-skin” time of 72 minutes seen in this study is virtually identical to recent studies comparing conventional and patient specific jigs, which are claimed to have shorter operating times [7] and much shorter than times quoted for other recent navigation series [3], [7], [17]. In our institution, with the use of navigation routinely, operation times appear to still be within the range that would be expected for non-navigated surgery.…”

“…Although it has been shown that image-free computer-navigated total knee arthroplasty (TKA) improves component positioning and overall lower limb alignment [1], [2], [3], [4], it has not been widely adopted. This is due to a number of criticisms including that it increases operation times and the risks of problems with the tracker bone screw insertion sites [1], [5], [6], [7], [8], [9], [10], [11].…”

Radiographic assessment and clinical outcomes after total knee arthroplasty using an accelerometer-based portable navigation device

“…reported that varus lower limb alignment after TKA resulted in poor self-reported clinical outcomes using the New KSS. Gothesen et al [24]. reported that TKA using CAS achieved better alignment and clinical alignment than conventional technique.…”

(i) Computer assisted surgical navigation (CASN) in total knee replacement. Soft tissue balancing and the role of dynamic assessment

“…31 More recent studies have begun to show some evidence of functional efficacy including KOOS (Knee Injury and Osteoarthritis Outcome Score) scores at one year over conventional techniques, as well as a consistent demonstration of improved component and limb alignments known to be important in long term component survival. 32 Thus it is hoped that computer navigation, by leading to higher proportions of accurately aligned knee prostheses, including sizing and rotations, will lead to increased longevity and improved function, but this will remain unproven until long term clinical outcomes of CASN assisted TKR's can be correlated with detailed analysis of intra-operative events.…”