Cementless and locked prosthesis for the treatment of 3-part and 4-part proximal humerus fractures: prospective clinical evaluation of hemi- and reverse arthroplasty.

INTRODUCTION: Cemented stem remains the gold standard for prosthesis in trauma. The purpose of this study was to evaluate the functional and radiological outcomes of a cementless, trauma-specific locked stem (hemi and reverse) for 3- and 4-part proximal humeral fractures.

MATERIALS AND METHODS: One hundred and thirty-four 3- and 4-part fractures have been treated by locked stem, 69 with hemiarthroplasty [mean age 68 years (50-90)] and 65 with reversed [mean age 78 years (66-91)]. The length of the stem was 15 cm with a proximal coating of HA automatic locking system (two screws) and four different diameters. Preliminary cadaver study allowed us to validate the system (22 shoulders, no injuries of nerves, locking system efficient).

RESULTS: In the group of hemi, Constant score with ponderation reached 72 (11-120) and QDash 31.2 (4.5-77.27) with a mean FU of 25 months (6-96). In the group of reversed, Constant score with ponderation reached 77.6 (28.8-119) and QDash 36.2 (2-84) with a mean FU of 15 months (6-41). Specific complications due to locking system reached 3% but without reoperation. Other complications were capsulitis and infection.

DISCUSSION: In this population of elderly patient, new fall with periprosthetic fracture or infection led the surgeon to remove the stem. At shoulder level, the removal of a cemented stem remains a highly demanding procedure with sometimes bad functional results and elevated level of complications. This series is the first one of locked stem without significant complications. Locked stem remains a new but logical tool in trauma.