Open AccessCT‐based patient‐specific instrumentation for total knee arthroplasty in over 700 cases: single‐use instruments are as accurate as standard instruments
Author(s) -
Gaukel Stefan,
VuilleditBille Raphael N.,
Schläppi Michel,
Koch Peter P.
Publication year - 2022
Publication title -
knee surgery, sports traumatology, arthroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.806
H-Index - 125
eISSN - 1433-7347
pISSN - 0942-2056
DOI - 10.1007/s00167-020-06150-x
Subject(s) - medicine , total knee arthroplasty , nuclear medicine , radiological weapon , arthroplasty , instrumentation (computer programming) , orthodontics , surgery , computer science , operating system
Purpose Efforts in total knee arthroplasty are made to improve accuracy for a correct leg axis and reduce component malpositioning using patient‐specific instruments. It was hypothesized that use of patient‐specific instruments (vs. computer‐navigated and conventional techniques) will reduce the number of outliers. Our second hypothesis was that single‐use instrumentation will lead to the same accuracy compared to patient‐specific instruments made of metal. Methods 708 primary total knee arthroplasties between 2014 and 2018 using computer tomography (CT)‐based patient‐specific cutting block technique and a preoperative planning protocol were retrospectively reviewed. Preoperative data [hip–knee–angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), tibial slope, femoral component flexion] was compared to postoperative performed standard radiological follow‐up X‐rays. Differences of > 3° between measurements were defined as outliers. Results Overall 500 prostheses using standard instrumentation and 208 prostheses using single‐use instruments were implanted. Preoperative HKA axes (− 1.2°; p < 0.001), femoral component flexion (Δ 0.8°, p < 0.001), LDFA (Δ − 1.5°, p < 0.001), MPTA (Δ − 0.5°, p < 0.001) and tibial posterior slopes (Δ 0.5°, p < 0.001), respectively, were different from postoperative axes. More outliers occurred using standard (vs. single‐use) instruments ( p < 0.001) regarding postoperative HKA (ranges of standard‐ vs. single‐use: instruments: HKA 178.0°–180.5° vs. 178.0°–180.5°, femoral component flexion 0.0°–6.0° vs. 0.0°–4.5°, LDFA 90.0°–91.0° vs. 90.0°–90.0°, MPTA 90.0°–90.0° vs. 90.0°–90.0°, tibial posterior slope − 10° to 10° vs. − 1° to 10°). No differences were seen for other angles measured. Comparing both systems, total number of outliers was higher using standard (8%) vs. single‐use instruments (4.3%). Conclusion This study shows a high accuracy of CT‐based patient‐specific instrumentation concerning postoperative achieved knee angles and mechanical leg axes. Single‐use instruments showed a similar accuracy. Level of evidence III.