New precontoured long locking plate for proximal metadiaphyseal fractures of the humerus: a cadaveric study for its use with the minimally invasive technique

Abstract

Background The purpose of this study was to identify nerves at risk when using a minimally invasive plate osteosynthesis precontoured long proximal humerus locking plate and to evaluate the risk of injury to deltoid insertion and brachialis muscle. Methods Ten cadaveric upper limb specimens were used. A transdeltoid anterolateral approach was performed proximally and a second anterior approach was performed distally. A 14-hole “low” long precountored ALPS locking plate (Biomet Trauma; Zimmer Biomet, Warsaw, IN, USA) was used. Subsequently, anatomic dissection to measure the anatomic relationship of the plate with the deltoid insertion, with the brachialis muscle, and with the axillary, radial, and musculocutaneous nerves was performed. Results The mean humeral length was 302 mm (standard deviation 52.3, 99% confidence interval: 259.3-344.6). In 6 specimens, the axillary nerve was located at the level of the third row of holes of the plate; in 3 specimens, at the level of the fourth row; and in one specimen, at the level of the second row. The distance between the plate and the musculocutaneous nerve was on average 10.2 mm (standard deviation 4, 99% confidence interval: 6.9-13.5) and between the plate and the radial nerve was on average 7.9 mm (standard deviation 4.7, 99% confidence interval: 4-11.8). The plate pierced the anterior distal fibers of the deltoid in all specimens. In 8 specimens, no brachialis muscle fibers were located under the plate. Conclusions The use of the long precontoured 14-hole ALPS locking plate with the minimally invasive plate osteosynthesis technique, previously identifying the axillary and musculocutaneous nerves, is feasible; however, the distances between the plate and the nerves remain low, so caution should be maintained. Despite the curved design of the plate, the deltoid insertion is partially compromised in all cases.

Helical Plating Compared with Straight Plating and Nailing for Treatment of Proximal Third Humeral Shaft Fractures—A Biomechanical Study

“…The twisted plate winds around a single point in two distinct planes, whereas a helical plate follows a three-dimensional curve that lies on a cylinder while its angle progression remains constant in a plane perpendicular to the axis. The capability of the ALPS to avoid the axillary and musculocutaneous nerves has already been demonstrated in a cadaveric study with 10 specimens [32]. Furthermore, equitable healing rates and clinical outcomes-as compared with straight plates-were reported by Argyropoulos et al [33].…”

Arthroplasty as Primary Treatment for Metadiaphyseal Proximal Humerus Fractures: A Viable Alternative to Osteosynthesis for the Elderly

“…Although this is theorized to have the benefit of avoiding the deltoid insertion and neurovascular structures, the minimally invasive surgical technique can be technically challenging. 14 , 15 On the other hand, RTSA for surgical treatment of these fractures has its unique set of challenges due to compromised bony fixation in the metaphyseal region, requiring longer prosthesis or cementation for increased stability. 16 Garofalo et al previously reported satisfactory results using cemented long-stem RTSA with cerclage wire for the treatment of these complex fractures with metaphyseal extension.…”