Minimally Invasive Percutaneous Plate Osteosynthesis via a Deltoid-splitting Approach with Strut Allograft for the Treatment of Displaced 3- or 4-part Proximal Humeral Fractures

Abstract

Background: This study introduces a surgical technique with good clinical outcome useful in the treatment of osteoporotic displaced 3- or 4-part proximal humeral fractures. Methods: From May 2014 to February 2016, 16 patients with displaced 3- or 4-part proximal humeral fractures were treated by application of a locking plate with an endosteal strut allograft via a deltoid splitting approach with a minimum follow-up of 12 months. The allograft was inserted through a fractured gap of the greater tuberosity to support the humeral head and then fixed by a locking plate with meticulous soft tissue dissection to protect the axillary nerve. Surgical outcomes were evaluated by the American Shoulder and Elbow Surgeons (ASES) and visual analogue scale (VAS) scores, radiological imaging, and clinical examination. Fixation failure on radiographs was defined as a >$5^{\circ}$ loss of neck shaft angle (NSA) compared to that on an immediate postoperative radiograph. Avascular necrosis (AVN) of the humeral head was also evaluated. Results: In all cases, complete union was achieved. The ASES and VAS scores were improved to $85.4{\pm}2.1$ and $3.2{\pm}1.3$, respectively. Twelve patients (75.0%) had greater than a $5^{\circ}$ change in NSA; the average NSA change was $3.8^{\circ}$. Five patients (31.3%) had unsatisfactory ranges of motion exhibiting a <$100^{\circ}$ active forward flexion. No axillary nerve injuries or AVN were observed at the last follow-up. One patient was converted to reverse total arthroplasty due to severe pain and functional deficit. Conclusions: Minimally invasive fixation via a locking compression plate and an endosteal fibula strut allograft in Neer classification 3-or 4-part fractures with severe osteoporosis in elderly patients can achieve good clinical results.

Fig. 1. Deltoid splitting approach using a minimally invasive percutaneous plate osteosynthesis technique. (A) A photograph at a distance from the anterolateral border of the acromion to prevent axillary nerve injury. (B) Image of the initial deltoid splitting incision. (C) Image of the two separated incisions after internal fixation was completed. (D) A photograph after the skin suturing was finished.

Fig. 2. The sequence of surgical techniques we used. Use of the deltoid-splitting approach (two separate incisions). (A) Fibula strut allograft was inserted through the fracture gap of the greater tuberosity. (B) After allograft insertion, the remnant bone was cut off at its proximal aspect. (C, D) Fracture site was reduced and the locking plate was positioned with temporary K-wire fixation. (E) Ethibond suturing was used to anchor the rotator cuff muscles to the locking plate. (F) Postoperative anteroposterior plain radiograph of the right shoulder.

Fig. 4. A case of using our surgical technique. A 79-year-old woman whose bone mineral density score was -4.0 was injured in a pedestrian accident. (A) A plain radiograph shows a Neer classification 3-part proximal humeral fracture. (B, C) Three-dimensional computed tomography images show the same fracture. Using deltoid splitting incisions, a fibula strut allograft was inserted through the greater tuberosity fracture gap. (D, E) The locking plate was positioned with temporary K-wire fixation. (F) Definite fixation was accomplished. (G) The deltoid splitting incision and the fixated locking plate. (H) An anteroposterior view of the neck shaft angle (NSA) (132°).

Fig. 3. Paavolainen method. Using an anteroposterior radiograph, the humeral neck shaft angle was determined by examining the intersection of a line drawn on the central axis of the humeral shaft (line A) with line C drawn perpendicular to the anatomical neck (line B) of the humerus (normal range: 120°–140°).

Fig. 5. A case of the role of mechanical support of the strut allograft. A 68-year-old male patient underwent surgery using our minimally invasive percutaneous plate osteosynthesis method. (A, B) Surgical outcome was radiologically satisfactory immediately after surgery. (C, D) Radiographs showing implant failure at the patient’s 3-month follow-up. However, bone union was finally obtained due to the mechanical supporting role of the fibula strut allograft buttress. (E, F) Images are radiographs after metal removal operation at the 12-month follow-up.

Table 1. Summary of Patient Characteristics