Patient-specific instruments do not show advantage over conventional instruments in unicompartmental knee arthroplasty at 2 year follow-up: a prospective, two-centre, randomised, double-blind, controlled trial

Abstract

Purpose The aim of this two-centre RCT was to compare pre-and post-operative radiological, clinical and functional outcomes between patient-speciic instrumentation (PSI) and conventional instrumented (CI) unicompartmental knee arthroplasty (UKA). It was hypothesised that both alignment methods would have comparable post-operative radiological, clinical and functional outcomes. Methods One hundred and twenty patients were included, and randomly allocated to the PSI or the CI group. Outcome measures were peri-operative outcomes (operation time, length of hospital stay and intra-operative changes of implant size) and post-operative radiological outcomes including the alignment of the tibial and femoral component in the sagittal and frontal plane and the hip-knee-ankle-axis (HKA-axis), rate of adverse events (AEs) and patient-reported outcome measures (PROMs) pre-operatively and at 3, 12 and 24 months post-operatively. Results There was a statistically signiicant diference (p < 0.05) in alignment of the femoral component in the frontal plane in favour of the CI method. No statistically signiicant diferences were found for the peri-operative data or in the functional outcome at 2-year follow-up. In the PSI group, the approved implant size of the femoral component was correct in 98.2% of the cases and the tibial component was correct in 60.7% of the cases. There was a comparable rate of AEs: 5.1% in the CI and 5.4% in the PSI group. ConclusionThe PSI method did not show an advantage over CI in regard of positioning of the components, nor did it show an improvement in clinical or functional outcome. We conclude that the possible advantages of PSI do not outweigh the costs of the MRI scan and the manufacturing of the PSI. Level of evidence Randomised controlled trial, level I.

Patient Specific Instruments and Patient Individual Implants—A Narrative Review

“…There are conflicting results regarding unicondylar arthroplasty, with each of three papers showing advantages in implantation accuracy [ 20 , 21 , 22 ] and no advantages in accuracy nor outcome [ 23 , 24 , 25 ], respectively.…”

The efficacy and safety of patient-specific instrumentation versus conventional instrumentation for unicompartmental knee arthroplasty: Evidence from a meta-analysis

“…After removing 196 duplicate articles, screening of titles, abstracts, and full texts was conducted according to the inclusion criteria. Ultimately, 9 studies [19][20][21][22][23][24][25][26][27] met the quality assessment and were included for data extraction. The process of study selection and inclusion is shown in Figure 1B.…”

“…Four studies [19,20,22,25] reported postoperative complications, with 5 cases in the PSI group and 10 cases in the CI group. A fixed-effects model was used for the meta-analysis and the results showed no statistically significant difference between the 2 groups (RR = 0.41, 95% CI: 0.16-1.05, P = .06) (Fig.…”

“…4A). A total of 7 studies [19,[21][22][23][24][25][26] reported the surgical duration for the 2 groups, with 200 cases in the PSI group and 183 cases in the CI group. The results of the heterogeneity test indicated high heterogeneity among the studies (I² = 97%) and random-effects model was used.…”

“…4C). A total of 4 studies [19,[25][26][27] reported the postoperative knee joint function assessed by the 12-item Short-Form, the Knee Society Score, the Knee Injury and Osteoarthritis Outcome Score, and the Oxford Knee Score.…”