A high rate of tibial plateau fractures after early experience with patient-specific instrumentation for unicompartmental knee arthroplasties

A. M. Leenders, M. G. M. Schotanus*, R. J. P. Wind, R. A. P. Borghans, N. P. Kort

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


PurposePatient-specific instrumentation (PSI) for unicompartmental knee arthroplasty (UKA) has been available for a few years. However, limited literature is available on this subject. Hence, the aim of this cohort study is to evaluate the 2years' results of our first experiences with the use of PSI in UKA. It is hypothesised that there is no advantage in rate of adverse events and in radiological and functional outcomes in comparison to literature on the conventional method.MethodsThis cohort included 129 knees of 122 patients, operated by one surgeon. Outcome measures were the rate of adverse events (AEs); implant position as determined on radiographs; the accuracy of the default and approved planning of the implant sizes and the patient-reported outcome measures (PROMs) preoperatively, and at 3, 12 and 24months, postoperatively.ResultsA total of 6 (4.9%) AEs were observed in this study, with 4 (3.3%) tibial fractures being the main complication. The mean postoperative biomechanical axis was 176.4 degrees and in the majority of cases, the radiographic criteria, as determined by the manufacturer, were met. The tibial component showed 20 (16.4%) outliers in the sagittal and 3 (2.5%) outliers in the frontal plane. There were no outliers of the femoral component. For the femoral and tibial components, respectively, in 125 (96.9%) and 79 (61.7%) cases, there was an agreement between approved planning and implanted component size. All PROMs improved significantly after surgery.ConclusionTibial fracture was the most common AE, probably related to the transition from cemented to uncemented UKA. Perioperative modifications to the surgical technique were made in order to prevent this AE. Improvements should be made to the operation technique of the uncemented tibial plateau to obtain an adequate placement and at the same time reduce the risk for tibial fracture. The PSI technique was a reliable tool for the placement of the femoral component. Functional outcome was in line with literature on the conventional method. It is strongly recommended that the surgeon approves every preoperative plan, in order to optimise the accuracy during the PSI surgery.Level of evidenceIII.
Original languageEnglish
Pages (from-to)3491-3498
Number of pages8
JournalKnee Surgery Sports Traumatology Arthroscopy
Issue number11
Publication statusPublished - 1 Nov 2018


  • Patient-specific matched instruments
  • Patient-specific guides
  • Patient specific
  • Instruments
  • Templating
  • Custom fit
  • Unicompartmental knee arthroplasty
  • Unicondylar knee arthroplasty
  • UKA
  • PSI
  • PSG

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