Preliminary biomechanical cadaver study investigating a new load-sharing knee implant

Mehdi Saeidi,Piaras A Kelly,Thomas Neitzert,Pranesh Kumar,Christian Netzel,Miriam Scadeng,Deborah Prendergast,Maziar Ramezani

doi:10.1186/s40634-021-00379-2

Abstract

PurposeOne of the major contributors to the progression of knee osteoarthritis (OA) is the condition of loading in the knee joint. Innovatively designed load-sharing implants may be effective in terms of reducing joint load. The effects of these implants on contact joint mechanics can be evaluated through cadaver experiments. In this work, a case study is carried out with cadaver knee specimens to carry out a preliminary investigation into a novel load-sharing knee implant, in particular to study the surgical procedures required for attachment, and to determine the contact pressures in the joint with and without the implant.MethodsContact pressure in the tibiofemoral joint was measured using pressure mapping sensors, with and without the implant, and radiographs were conducted to investigate the influence of the implant on joint space. The implant was designed from a 3D model of the specimen reconstructed by segmenting MR images of the knee, and it was manufactured by CNC machining.ResultsIt was observed that attachment of the implant does not affect the geometry of the hard/soft tissues. Radiographs showed that the implant led to an increase in the joint space on the medial side. Contact pressure measurements showed that the implant reduced the load on the medial side by approximately 18% under all tested loading conditions. By increasing the load from 800 to 1600 N, the percentage of load reduction in the lateral side was decreased by 8%. After applying 800, 1200, and 1600 N load it was observed that the peak contact pressures were 3.7, 4.6, and 5.5 MPa, respectively.ConclusionsThis new knee implant shows some promise as a treatment for OA, through its creation of a conducive loading environment in the knee joint, without sacrificing or damaging any of the hard or soft tissues. This device could be as effective as, for example, the Atlas® system, but without some complications seen with other devices; this would need to be validated through similar results being observed in an appropriate in vivo study.

Highlights

Knee osteoarthritis (OA) is one of the major causes of musculoskeletal impairment in adults
This new knee implant shows some promise as a treatment for OA, through its creation of a conducive loading environment in the knee joint, without sacrificing or damaging any of the hard or soft tissues
Surgical procedure After making an incision (Fig. 10a), exposing the Medial Collateral Ligament (MCL) (Fig. 10b) and attachment of the implant, the knee joint was examined at different flexion angles as shown in Fig. 10c – e

Summary

Introduction

Knee osteoarthritis (OA) is one of the major causes of musculoskeletal impairment in adults. Initiation and progression of the OA pathology are largely associated with excessive and aberrant knee loading; other factors, such as trauma and genetics would be influential as well. This disease is mainly characterised by progressive degeneration of the articular cartilage and, to date, there is no known cure for knee osteoarthritis [10, 11, 15, 18]. The occurrence of those injuries in younger adults may lead to osteoarthritis when they are in their 30s or 40s [19]

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