Impact of keel saw blade design and thickness on the incidence of tibial plateau fracture and tibial implant-loosening in cementless medial UKR

Lena Keppler; Steffen Klingbeil; Alexander Martin Keppler; Johannes Becker; Christian Fulghum; Björn Michel; Kilian Voigts; Wolfgang Reng

doi:10.1186/s12891-022-05500-9

Impact of keel saw blade design and thickness on the incidence of tibial plateau fracture and tibial implant-loosening in cementless medial UKR

BMC Musculoskelet Disord. 2022 Jun 21;23(1):597. doi: 10.1186/s12891-022-05500-9.

Authors

Lena Keppler¹, Steffen Klingbeil², Alexander Martin Keppler³, Johannes Becker², Christian Fulghum², Björn Michel², Kilian Voigts², Wolfgang Reng⁴

Affiliations

¹ BG Trauma Center Murnau, Trauma Surgery, Prof. Kuentscher Straße 8, 82418, Murnau, Germany.
² Klinikum Garmisch-Partenkirchen, Endogap, Joint Replacement Institute, Auenstraße 6, 82467, Garmisch-Partenkirchen, Germany.
³ Department of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, 81377, Munich, Germany.
⁴ Klinikum Garmisch-Partenkirchen, Endogap, Joint Replacement Institute, Auenstraße 6, 82467, Garmisch-Partenkirchen, Germany. wolfgang.reng@klinikum-gap.de.

Abstract

Background: Tibial plateau fractures and tibial implant- loosening are severe complications in cementless unicompartmental knee replacement (UKR). The tibial keel preparation is particularly demanding and different saw blades can be used. It was hypothesized that different blade designs and thickness have an influence on the frequency of tibial plateau fractures and implant-loosening in cementless medial UKR.

Methods: 1258 patients with cementless medial UKR were included in this retrospective study between 2013 and 2020. The tibial keel cut was performed either with a double keel saw blade (DKS; 2.8 mm) and added hand guided pick or a mono reciprocating saw blade (RKB) of different thickness (2.5 mm; 2.65 mm; 2.75 mm). Tibial plateau fracture and loosening were demonstrated by standard two-plane radiographs. Tibial implant-loosening was defined as complete radiolucency and implant migration. Fracture and loosening were combined with pain and loss of function.

Results: In 126 patients (10%) the tibial keel was prepared with DKS, in 407 patients (32.4%) with RKB 2.5 mm, in 330 patients (26.2%) with RKB 2.65 mm and in 395 patients (31.4%) with 2.75 mm. In 4 patients (3.17%) with DKS tibial plateau fracture occurred, in 4 patients (0.99%) with 2.5 mm RKB, in 3 patients (0.92%) with 2.65 mm RKB and in 1 patient (0.25%) with 2.75 mm RKB. Significantly fewer fractures occurred with a RKB design (p = 0.007). A negative correlation between fracture incidence and RKB saw blade thickness was found (Spearman-r = - 0.93). No difference for tibial implant-loosening was shown (p = 0.51).

Conclusion: Different blade designs and thickness have a significant influence on the incidence of tibial plateau fractures and aseptic tibial implant-loosening. The incidence of tibial plateau fractures in cementless medial UKR can be reduced by changing the design and thickness of the tibial keel saw blade. Greater thickness of RKB leads to significantly fewer tibial plateau fractures while the incidence of implant-loosening is not increasing.

Trial registration: This study was retrospectively registered and ethical approval was waived by the local ethical committee (No. 2020-1174).

Keywords: Fracture incidence; Influence; Outcome; Revision surgery; Saw blade.

MeSH terms

Arthroplasty, Replacement, Knee* / adverse effects
Humans
Incidence
Knee Prosthesis* / adverse effects
Prosthesis Design
Retrospective Studies
Tibial Fractures* / diagnostic imaging
Tibial Fractures* / epidemiology
Tibial Fractures* / surgery