The 45-year evolution of the Mathys RM monoblock cups: have the paradigm shifts been worthwhile?

Autor:	Foxall-Smith M; Trauma and Orthopaedics Department, Southmead Hospital, Bristol, UK., Wyatt MC; Department of Trauma and Orthopaedic Surgery, Palmerston North Hospital, Massey University, Manawatu, New Zealand., Frampton C; Department of Surgery and Musculoskeletal Medicine, University of Otago, New Zealand., Kieser D; Department of Surgery and Musculoskeletal Medicine, University of Otago, New Zealand., Hooper G; Department of Surgery and Musculoskeletal Medicine, University of Otago, New Zealand.
Jazyk:	angličtina
Zdroj:	Hip international : the journal of clinical and experimental research on hip pathology and therapy [Hip Int] 2023 Mar; Vol. 33 (2), pp. 193-202. Date of Electronic Publication: 2022 Apr 19.
DOI:	10.1177/11207000211067507
Abstrakt:	Introduction: The Robert Mathys (RM) monoblock uncemented cup is a design less commonly used in primary total hip replacement. It's purported advantages over modular cemented cups are: (1) its modulus of elasticity approximating bone, thus mimicking load transmission and the biomechanical behaviour of the cup to better match stresses on the acetabulum, leading to bone-preservation; and (2) as a 1-piece cup there is absence of a mobile interface between a liner and shell, preventing backside wear. Since its inception in 1983 there have been 3 major design changes: the RM Classic, the RM Pressfit, and the RM Vitamys with the most modern polyethylene (vitamin E). Methods: In a retrospective cohort study of the New Zealand Joint Registry, all designs of RM acetabular cup were reviewed. Data were included from1998 to 2018. All-cause revision rates, reasons for revision and the Oxford Hip Score (OHS) were assessed. Results: In total 13,272 acetabular cups were included. The all-cause revision rates did not differ between the designs. Revision rates for aseptic loosening in the RM Vitamys were lower, but the follow-up was shorter and more larger heads were used. There was no difference in the OHS. Conclusion: All implant designs were safe. The use of larger heads led to a decrease in revisions due to dislocation. It has to be waited out whether the RM Vitamys performs superior in the long-term due to the highly cross-linked polyethylene.
Databáze:	MEDLINE
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