Varus or valgus positioning of the tibial component of a unicompartmental fixed-bearing knee arthroplasty does not incre
- PDF / 696,233 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 97 Downloads / 191 Views
KNEE
Varus or valgus positioning of the tibial component of a unicompartmental fixed‑bearing knee arthroplasty does not increase wear Matthias Woiczinski1 · Christian Schröder1 · Alexander Paulus1 · Manuel Kistler1 · Volkmar Jansson1 · Peter E. Müller1 · Patrick Weber1,2 Received: 13 June 2019 / Accepted: 15 October 2019 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2019
Abstract Purpose Higher revision rates were shown in varus- or valgus-positioned tibias in unicompartmental knee arthroplasty (UKA), but more than 15% of UKA prostheses are implanted with more than 5° of varus or valgus. This study aimed to analyze the wear rate in UKA when implanting the tibial component in either varus or valgus position versus a neutral placement at 90° to the tibial anatomical axis. The study hypothesized that a 5° varus or valgus positioning of the tibial plateau will generate less wear compared to a neutral alignment. Methods Wear was experimentally analyzed on a medial anatomical fixed-bearing unicompartmental knee prosthesis (Univation, Aesculap, Germany) in vitro with a customized, four-station, servohydraulic knee wear simulator, reproducing the walking cycle. The forces, loading and range of motion were applied as specified in the ISO 14243–1:2002, 5 million cycles were analyzed. The tibial components of the medial prostheses were inserted in a neutral position, with 5° varus, and 5° valgus (n = 3, each group). Results The wear rate decreased significantly with a 5° varus positioning (6.30 ± 1.38 mg/million cycles) and a 5° valgus positioning (4.96 ± 2.47 mg/million cycles) compared to the neutral position (12.16 ± 1.26 mg/million cycles) (p
Data Loading...
