No implant migration and good subjective outcome of a novel customized femoral resurfacing metal implant for focal chondral lesions

Abstract

PurposeManaging focal cartilage injuries in the middle-aged patient poses a challenge. Focal prosthetic inlay resurfacing has been proposed to be a bridge between biologics and conventional joint arthroplasty. Patient selection and accurate implant positioning is crucial to avoid increased contact pressure to the opposite cartilage surface. A customized femoral condyle implant for focal cartilage injuries was designed to precisely fit each patient’s individual size and location of damage. The primary objective was to assess implant safety profile, surgical usability of the implant and instruments, and implant migration with radiostereometric analysis (RSA).MethodsTen patients 36–56 years with focal chondral defects, ICRS 3–4 of the femoral cartilage and failed earlier conservative or surgical interventions with VAS pain > 40. The patients were followed for 2 years with subjective outcome measures (VAS, EQ5D, KOOS) and RSA. The customized implant and guide instruments were manufactured by computer-aided design/computer-aided manufacturing (CAD/CAM) techniques using MRI data.ResultsVAS, EQ5D and KOOS showed improvements that reached significance for VAS (p ≤ 0.001), Tegner (p = 0.034) and the KOOS subscores ADL (p = 0.0048), sport and recreation (p = 0.034) and quality of life (p = 0.037). VAS and KOOS scores improved gradually at 3, 6 and 12 months. The improvements in EQ5D, KOOS pain and KOOS symptoms did not reach statistical significance. No infections, deep venous thrombosis or other complications occured in the postoperative period. No radiographic signs of damage to the opposing tibial cartilage was noted. The surgical usability of implants and instruments were good. RSA did not show any implant migration.ConclusionThis is the first clinical report of a new customized, focal knee resurfacing system. The short-term implant safety and patient-related outcome measures showed good-to-excellent results.Level of evidenceProspective case series, Level 4.

In vitro and in vivo study on the osseointegration of BCP‐coated versus uncoated nondegradable thermoplastic polyurethane focal knee resurfacing implants

“…However, both auto‐ and allografting are hampered by drawbacks such as donor‐site morbidity (Andrade et al, 2016) and limited availability (Gobbi, Scotti, Lane, & Peretti, 2015). FKRIs are an emerging group of implants typically intended for the treatment of cartilage defects in middle‐aged patients, which may fill the treatment gap (Fuchs et al, 2018; Nathwani, McNicholas, Hart, Miles, & Bobic, 2017; Stalman et al, 2018).…”

“…Most FKRIs approved for clinical use are metal‐based, comprising a highly polished cobalt‐chromium articulating top to substitute cartilage and a titanium bone‐substituting base (Fuchs et al, 2018; Pascual‐Garrido, Daley, Verma, & Cole, 2017; Skoldenberg et al, 2014; Stalman et al, 2018). A primary prerequisite for FKRIs is adequate fixation in the subchondral bone, in order to maintain congruency to the articular surface (Martinez‐Carranza et al, 2016; Stalman et al, 2018). Multiple studies have proven excellent osseointegration of titanium‐based FKRIs (Custers et al, 2010; Martinez‐Carranza et al, 2014; Stalman et al, 2018).…”

“…A primary prerequisite for FKRIs is adequate fixation in the subchondral bone, in order to maintain congruency to the articular surface (Martinez‐Carranza et al, 2016; Stalman et al, 2018). Multiple studies have proven excellent osseointegration of titanium‐based FKRIs (Custers et al, 2010; Martinez‐Carranza et al, 2014; Stalman et al, 2018). However, there are concerns regarding the articulation of native cartilage with metal implants.…”

Correlation Between Conditional Approval and Customized Bone Implant Devices

“…Recent study on custom‐designed bone implants has mainly focuses on dentures or teeth, maxillary or mandible, and femurs. Other notable implant types include those for the humerus, the cranium/skull, and the tibia …”

The cost-effectiveness of osteochondral allograft transplantation in the knee

“…Data on a more recent device, the second version of the Episealer, are as yet sparse, with two published accounts with ten [ 61 ] and two [ 6 ] patients. However, such patches may be an option in future once more data are available.…”