Novel metallic implantation technique for osteochondral defects of the medial talar dome

Abstract

Background and purposeA metallic inlay implant (HemiCAP) with 15 offset sizes has been developed for the treatment of localized osteochondral defects of the medial talar dome. The aim of this study was to test the following hypotheses: (1) a matching offset size is available for each talus, (2) the prosthetic device can be reproducibly implanted slightly recessed in relation to the talar cartilage level, and (3) with this implantation level, excessive contact pressures on the opposite tibial cartilage are avoided.MethodsThe prosthetic device was implanted in 11 intact fresh-frozen human cadaver ankles, aiming its surface 0.5 mm below cartilage level. The implantation level was measured at 4 margins of each implant. Intraarticular contact pressures were measured before and after implantation, with compressive forces of 1,000–2,000 N and the ankle joint in plantigrade position, 10° dorsiflexion, and 14° plantar flexion.ResultsThere was a matching offset size available for each specimen. The mean implantation level was 0.45 (SD 0.18) mm below the cartilage surface. The defect area accounted for a median of 3% (0.02–18) of the total ankle contact pressure before implantation. This was reduced to 0.1% (0.02–13) after prosthetic implantation.InterpretationThese results suggest that the implant can be applied clinically in a safe way, with appropriate offset sizes for various talar domes and without excessive pressure on the opposite cartilage.

Anterior ankle arthroscopy: state of the art

“…Partial resurfacing for treatment of large OCDs or secondary defects will gain acceptance. Since the approach to these defects remains a challenge, there is a need for patient-specific guided implants and instruments 95 96. For combined ankle and subtalar OA, one-stage combined arthroscopic ankle and subtalar fusion will be performed.…”

Novel Metal Implantation Technique for Osteochondral Defects of the Medial Talar Dome

“…10 In case of failure of the primary treatment, current secondary treatment options include osteochondral autograft transfer system, autogenous cancellous bone graft, and autologous chondrocyte implantation. 18 Its goals are to offer relief from pain, return to activity, and prevent degeneration/further cyst formation. 10 However, these techniques are associated with donor-site morbidity or involve 2-stage surgery.…”

Treatment of osteochondral defects of the talus with a metal resurfacing inlay implant after failed previous surgery

“…[4][5][6][7] In order to treat OCDs of the medial talar dome after failed primary treatment, a metal resurfacing inlay implant (HemiCAP; Arthrosurface Inc., Franklin, Massachusetts) has been developed. 8,9 The implant comprises two components: a cobalt-chromium modular articular component (diameter 15 mm) and a titanium cannulated screw, which are connected together via a taper interlock. The articular component is available in 15 incremental offset sizes, based on the surface geometry of the medial talar dome.…”

“…The articular component is available in 15 incremental offset sizes, based on the surface geometry of the medial talar dome. 8 Promising short-term clinical results have been reported with designs of similar implants used in various human joints. [10][11][12][13][14] Two mechanical cadaver studies provided a base line for the use of the talar implant in the ankle joint.…”

“…[10][11][12][13][14] Two mechanical cadaver studies provided a base line for the use of the talar implant in the ankle joint. 8,9 These studies showed that recessing the implant slightly relative to the level of the adjacent cartilage leads to acceptable contact stresses in the talocrural joint and is beneficial compared with leaving it proud. 8,9 The aim of this study was to evaluate the clinical effectiveness of the metal implant for OCDs of the medial talar dome after failed previous surgery.…”