Reconstruction of the anatomic defect following extra-articular shoulder resection is a challenging problem, particularly in cases when function of the deltoid muscle and rotator cuff are compromised. Standard reconstruction techniques often result in either instability or rigidity. Constrained implants have been used to overcome these problems; however, they have been associated with a high rate of aseptic loosening. Recently, a novel double-constrained implant has been introduced, yielding promising functional results. Nonetheless, this implant exhibited a cosmetic defect related to protrusion of the humeral component that becomes apparent with time as result of surrounding muscle atrophy. An updated improved design of the implant has been developed to counteract this.We report the case of a 15-year-old patient who underwent an extra-articular (Malawer type V) shoulder resection due to osteosarcoma and received an innovated custom-made double-constrained implant. Moreover, we describe a new modification of the Malawer utilitarian approach to the shoulder girdle that enhances tumor visibility and allows safer dissection. The patient recovered well with satisfactory outcomes at 18 months follow-up, highlighting the potential benefits of this implant design and surgical approach.

1st Department of Orthopaedics 1st Faculty of Medicine Charles University and Motol University Hospital Prague Czech Republic

Department of Orthopaedic Surgery University of Missouri 1100 Virgina Dr Columbia MO 65201 USA

Department of Orthopaedics 1st Faculty of Medicine Charles University and University Hospital Na Bulovce Kateřinská 1660 32 121 08 Nové Město Prague Czech Republic

Faculty of Mechanical Engineering Czech Technical University Prague Czech Republic

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