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J Knee Surg 2019; 32(09): 860-865
DOI: 10.1055/s-0038-1669448
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Early Failure in Medial Unicondylar Arthroplasty: Radiographic Analysis on the Importance of Joint Line Restoration

Mirco Lo Presti
1   2nd Orthopaedic and Traumatology Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy
,
Giovanni Francesco Raspugli
2   Department of Biomedical Sciences, Humanitas University, Humanitas Clinical and Research Center, Milan, Italy
,
Davide Reale
1   2nd Orthopaedic and Traumatology Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy
3   NABI Laboratory, IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
,
Francesco Iacono
2   Department of Biomedical Sciences, Humanitas University, Humanitas Clinical and Research Center, Milan, Italy
,
Stefano Zaffagnini
1   2nd Orthopaedic and Traumatology Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy
4   DIBINEM, Bologna University, Bologna, Italy
,
Giuseppe Filardo
3   NABI Laboratory, IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
,
Maurilio Marcacci
2   Department of Biomedical Sciences, Humanitas University, Humanitas Clinical and Research Center, Milan, Italy
› Author Affiliations
Further Information

Publication History

02 December 2017

23 July 2018

Publication Date:
13 September 2018 (online)

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Abstract

Survivorship of unicondylar knee arthroplasty (UKA) remains a drawback, especially compared with the outcome of total knee arthroplasty. This could be improved by identifying and correcting failure mechanisms. To this purpose, this study aimed at exploring failure modalities of UKA, with particular focus on the role of joint line (JL) position and alignment as variable to be optimized for a successful outcome. This study explored modes of failure in 266 medial UKAs. Radiological comparison was performed between 24 failures and 24 matched controls, to determine the importance of UKA positioning in terms of femorotibial angle (FTA), tibial plateau angle, and posterior tibial slope (PTS). Radiographic comparative analysis showed statistically significant differences in the failure group compared with the control group in terms of variation in FTA (p = 0.0222), PTS (p = 0.0025), and JL height (p = 0.0022). Variations not only in FTA but also PTS and JL height were correlated with failures observed in this series. Thus, based on the results of this study, it emerges that JL position should be carefully controlled in all planes while implanting a UKA. This is a Level III, case–control study.

Keywords

unicondylar knee arthroplasty - knee - joint line - alignment - failure mechanism